Close
About
FAQ
Home
Collections
Login
USC Login
Register
0
Selected
Invert selection
Deselect all
Deselect all
Click here to refresh results
Click here to refresh results
USC
/
Digital Library
/
University of Southern California Dissertations and Theses
/
Paleoecology and paleoenvironments of early Triassic mass extinction biotic recovery faunas, Sinbad Limestone Member, Moenkopi Formation, south-central Utah
(USC Thesis Other)
Paleoecology and paleoenvironments of early Triassic mass extinction biotic recovery faunas, Sinbad Limestone Member, Moenkopi Formation, south-central Utah
PDF
Download
Share
Open document
Flip pages
Contact Us
Contact Us
Copy asset link
Request this asset
Transcript (if available)
Content
NOTE TO USERS
This reproduction is the best copy available.
_ ®
UMI
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
PALEOECOLOGY AND PALEOENVIRONMENTS OF EARLY TRIASSIC
MASS EXTINCTION BIOTIC RECOVERY FAUNAS,
SINBAD LIMESTONE MEMBER, MOENKOPI FORMATION,
SOUTH-CENTRAL UTAH
by
Margaret Lee Fraiser
A Thesis Presented to the
FACULTY OF THE GRADUATE SCHOOL
UNIVERSITY OF SOUTHERN CALIFORNIA
In Partial Fulfillment of the
Requirements for the Degree
MASTER OF SCIENCE
(GEOLOGICAL SCIENCES)
December 2000
Copyright 2000 Margaret Lee Fraiser
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
UMI Number: 1 4 0 7 9 0 9
Copyright 2000 by
Fraiser, Margaret Lee
All rights reserved.
___ ®
UMI
UMI Microform 1407909
Copyright 2002 by ProQuest Information and Learning Company.
All rights reserved. This microform edition is protected against
unauthorized copying under Title 17, United States Code.
ProQuest Information and Learning Company
300 North Zeeb Road
P.O. Box 1346
Ann Arbor, Ml 48106-1346
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
UNIVERSITY OF SOUTHERN CALIFORNIA
The G raduate School
U niversity Park
LOS ANGELES, CALIFORNIA 900894695
This thesis, w ritten b y
Margaret Lee Fraiser
Under th e direction o f hS T.... Thesis
Com m ittee, and approved b y a ll its members,
has been p resen ted to and accepted b y The
Graduate School, in p a rtia l fulfillm ent o f
requirem ents fo r th e degree o f
Master of Science
Dean o f Graduate Studies
D a t e May 11. 2001
THESIS COMMITTEE
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
ACKNOWLEDGMENTS
ii
I would like to acknowledge the organizations that generously funded the field and
laboratory portions of this research. I thank the Geological Society of America, the
Paleontological Society, the American Museum of Natural History, the Wrigley Institute
for Environmental Studies, and the USC Department of Earth Sciences.
I extend my gratitude to the USC Department of Earth Sciences for aiding me
during my graduate school career here. Two of my committee members, Bob Douglas
and Dorm Gorsline, have been especially generous with their time and expertise in the
development of my research and me as a scientist.
To all of my PaleoLab officemates and labmates, Steve Dombos, Nicole Fraser,
Gerald Grellet-Tinner, Karina Hankins, Tran Huynh, Pedro Marenco, Sara Pruss, Dave
Rodland, Stephen Shellenberg, Rich Twitchett and Kate Woods, thank you for your
invaluable advice, both personal and professional. I treasure the time we spent and the
memories we made during classes and field trips and hanging out in the lab. Special
thanks to Pedro Marenco for being such a hard-working field assistant. Heartfelt thanks
to Steve for his unfaltering support, as well as his pacifying nature. I couldn’t have done
this without him.
I am forever indebted to my advisor Dave Bottjer for his patience and
understanding while this research was being conducted. I am grateful for the many hours
he spent teaching me in the field and in the office. He has been instrumental in my
development as a teacher, as a scientist, and as a person.
Thank you to my parents for showing me the world’s endless opportunities and for
giving me the courage to chase my dreams.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
TABLE OF CONTENTS
Page
Acknowledgments ii
List of Figures v
Abstract xi
Introduction 1
Permian Paleoecology 2
Life in Permian Seas 2
Permian Gastropods 3
The end-Permian Mass Extinction 6
Patterns of Extinction, Timing and Length of Occurrence 6
Proposed Causes 1 1
What went extinct 15
The Biotic Recovery Interval from the end-Permian Mass Extinction 18
Lengths and Phases of the Post-extinction Recovery 18
Early Triassic (Scythian) Paleoecology 21
Life After the Extinction 22
Early Triassic Gastropods, Microgastropods, and Bivalves 23
Modem Population Strategies 24
Opportunism (/--selection) and equilibrium situations (K-selections) 24
Biotic Recovery Opportunists 35
Definition of Biotic Recovery Opportunists 35
Purpose 36
Geologic Setting and Paleogeography 36
Global Paleogeography 36
Paleogeography of the Western United States 42
Moenkopi Formation 42
Sinbad Limestone Member 45
Methods 53
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
iv
Results 56
Stratigraphic Columns 56
Petrology and Taphonomy 186
Paleoenvironmental Analyses 238
Faunal Abundance Data 254
Ranking Results 266
Size Analysis 273
Ichnology 278
Discussion 278
Other Lower Triassic Localities (western USA) 278
Other Lower Triassic Localities (worldwide) 282
Sinbad Limestone Member - this study 282
Conclusions 284
References 287
Appendices 294
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
LIST OF FIGURES
Figure
1. Gastropod generic diversity.
2. Series and stages for the mid-Permian to Middle Triassic.
3. Relative fortunes of the marine biota during the Permian-Triassic crisis.
4. Diversity of marine animal families through the Phanerozoic.
5. Division of the post-extinction recovery phase.
6. Characteristics ofK-selected and r-selected organisms and populations.
7. S-shaped curve of the logistic model of population growth.
8. Characteristics ofK-selected and r-selected individuals.
9. J-shaped curve of the exponential model of population growth.
10. Relative temporal and abundance patterns for an opportunistic species.
11. Global paleogeography of Pangea.
12. Generalized paleogeography during the Early Triassic in Utah.
13. Exposures of the Moenkopi Formation of the Colorado Plateau and Utah.
14. Relationships of the Sinbad Limestone Member and the Thaynes Formation.
15. Map of Utah showing the San Rafael Swell and the Teasdale Uplift.
16. Photograph of the outcrop at the Roadcut Locality.
17. Stratigraphic column of the Sinbad Limestone Member, Roadcut Locality.
18. Photograph of the resistant skeletal packstone of Interval 10, Roadcut.
19. Photograph of a mudstone of the skeletal calcarenite, Roadcut.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
vi
20. Photograph of the micritic intervals of the silty pelloidal calcilutite, Roadcut. 66
21. Photograph of the intraclasts of the silty pelloidal calcilutite, Roadcut. 68
22. Photograph of the dolomitized caicarenite, Roadcut. 70
23. Stratigraphic column of the Batten and Stokes Locality. 72
24. Photograph of the lower peloidal wackestone, Batten and Stokes. 75
25. Photo of microgastropods of the peloidal wackestone, Batten and Stokes. 77
26. Photo of microgastropods in float, Batten and Stokes. 79
27. Photo of intervals 4, 5, and 6, skeletal caicarenite, Batten and Stokes. 81
28. Photo of mudstones of the skeletal caicarenite, Batten and Stokes. 83
29. Photo of micritic intervals of the silty peloidal calcilutite, Batten and Stokes. 85
30. Photo of alternation of non-resistant and resistant intervals, silty peloidal
calcilutite, Batten and Stokes. 87
31. Photo of the dolomitized caicarenite facies, Batten and Stokes. 89
32. Photo of Jackass Benches Locality. 91
33. Photo of outcrop at the Jackass Benches Locality. 93
34. Stratigraphic column of the Jackass Benches. 96
35. Photo of lower peloidal wackestone interval, Jackass Benches. 98
36. Photo of microgastropods in the lower peloidal wackestone, Jackass Benches. 100
37. Photo of bivalve-dominated skeletal packstone, Jackass Benches. 102
38. Photo of a typical skeletal packstone interval, Jackass Benches. 104
39. Photo of an ammonoid from float, skeletal packstone, Jackass Benches. 106
40. Photo of silty peloidal calcilutite, Jackass Benches. 108
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
vii
41. Photo of the dolomitized caicarenite facies, Jackass Benches. 110
42. Photo of the contact of the oolitic wackestone and the dolomitized caicarenite,
Jackass Benches. 112
43. Photo of the outcrop at the Black Box Locality. 115
44. Stratigraphic column of the Black Box Locality. 117
45. Photo of the basal peloidal wackestone at the Black Box. 119
46. Photo of the microgastropods of the basal peloidal wackestone, Black Box. 121
47. Photo of the skeletal caicarenite, Black Box. 123
48. Photo of an ammonoid in float, skeletal caicarenite, Black Box. 125
49. Photo of the convoluted bedding, silty peloidal calcilutite, Black Box. 127
50. Photo of the cross-bedding of the silty peloidal calcilutite, Black Box. 129
51. Photo of intervals 19-25 of the silty peloidal calcilutite, Black Box. 131
52. Photo of horizontal trace fossils of the silty peloidal calcilutite, Black Box. 133
53. Photo of a microgastropod, silty peloidal calcilutite, Black Box. 135
54. Photo of cross-bedding, dolomitized caicarenite, Black Box. 137
55. Photo of the outcrop of the Junction Locality. 140
56. Stratigraphic column of the Junction Locality. 142
57. Photo of cross-bedding, basal peloidal wackestone, Junction. 144
58. Photo of alternation of non-resistant and resistant intervals of the skeletal
caicarenite, Junction. 146
59. Photo of the cross-bedding, silty peloidal calcilutite, Junction. 148
60. Photo of the dolomitized caicarenite, Junction. 150
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
61. Photo of the outcrop at the Fish Creek Locality.
62. Stratigraphic Column of the Fish Creek Locality.
63. Photo of the cryptalgal bedding, Lithofacies A, Fish Creek.
64. Photo of microgastropods, Lithofacies A, Fish Creek.
65. Photo of abundant bivalves, Lithofacies A, Fish Creek.
66. Photo of trace fossils, Lithofacies A, Fish Creek.
67. Photo of trace fossils, Lithofacies A, Fish Creek.
68. Photo of trace fossils and microgastropods, Lithofacies B, Fish Creek.
69. Photo ofbioturbated interval, Lithofacies B, Fish Creek.
70. Photo of Lithofacies C, Fish Creek.
71. Photo of trace fossils, Lithofacies D, Fish Creek.
72. Photo of the dolomitized grainstone, Lithofacies E, Fish Creek.
73. Stratigraphic column of the Miners Mountain Locality.
73. continued.
74. Photo of the cryptalgal bedding, Lithofacies A, Miners Mountain.
75. Photo of the oolite-peloid packstone, Lithofacies A, Miners Mountain.
76. Photo of trace fossils, Lithofacies D, Miners Mountain.
77. Thin section photo of the peloidal packstone, skeletal caicarenite, Roadcut.
78. Thin section photo of skeletal packstone, skeletal caicarenite, Roadcut.
79. Thin section photo of peloidal wackestone, skeletal caicarenite, Batten and
Stokes.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
80. Thin section photo of skeletal packstone, skeletal caicarenite, Batten and
Stokes.
81. Thin section photo of peloidal packstone, skeletal caicarenite, Jackass
Benches.
82. Thin section photo of a skeletal packstone, skeletal caicarenite, Jackass
Benches.
83. Thin section photo of a skeletal packstone, skeletal caicarenite, Jackass
Benches.
84. Thin section photo of the oolitic wackestone, Jackass Benches.
85. Thin section photo of peloidal packstone, skeletal caicarenite, Black Box.
86. Thin section photo of skeletal wackestone, skeletal caicarenite, Black Box.
87. Thin section photo of a skeletal packstone, skeletal caicarenite, Junction.
88. Thin section photo of a skeletal packstone, skeletal caicarenite, Junction.
89. Thin section photo of a skeletal packstone, skeletal caicarenite, Junction.
90. Thin section photo of a skeletal wackestone, Lithofacies A, Fish Creek.
91. Thin section photo of a skeletal wackestone, Lithofacies A, Fish Creek.
92. Thin section photo of a skeletal packstone, Lithofacies B, Fish Creek.
93. Thin section photo of a skeletal packstone, Lithofacies B, Fish Creek.
94. Thin section photo of a skeletal packstone, Lithofacies B, Fish Creek.
95. Thin section photo of a skeletal packstone, Lithofacies B, Fish Creek.
96. Thin section photo of a skeletal wackestone, Lithofacies D, Fish Creek.
97. Thin section photo of a skeletal wackestone, Lithofacies D, Fish Creek.
98. Thin section photo of a skeletal packstone, Lithofacies D, Fish Creek.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
99. Thin section photo of a peloidal packstone, Lithofacies A, Miners Mountain. 236
100. Thin section photo of a skeletal packstone, Lithofacies B, Miners Mountain. 239
101. Thin section photo of a skeletal packstone, Lithofacies B, Miners Mountain. 241
102. Thin section photo of a skeletal packstone, Lithofacies D, Miners Mountain. 243
103. Thin section photo of a skeletal packstone, Lithofacies D, Miners Mountain. 245
104. Thin section photo of a skeletal packstone, Lithofacies D, Miners Mountain. 247
105. Diagram of Sinbad Sea depositional environments. 252
106. Faunal abundance data for Roadcut, Batten and Stokes, Jackass Benches, and
Black Box Locality intervals. 255
107. Faunal abundance data for Junction, Fish Creek, Miners Mountain Locality intervals.
257
108. Faunal abundance data for Roadcut, Batten and Stokes, Jackass Benches, and
Black Box Locality facies. 260
109. Faunal abundance data for Junction, Fish Creek, and Miners Mountain Locality
facies. 262
110. Faunal abundance data for combined San Rafael Swell and Teasdale Uplift facies.
264
111. Interval rankings for all facies of the Sinbad in the San Rafael Swell. 267
112. Interval rankings for Lithofacies A, B, and C of the Sinbad in the Teasdale Uplift.
269
113. Interval rankings for Lithofacies D and E of the Sinbad in the Teasdale Uplift.
271
114. Histograms of microgastropod size for skeletal caicarenite and dolomitized
caicarenite, San Rafael Swell. 274
115. Histograms of microgastropod size for Lithofacies A and B, Teasdale Uplift. 276
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
116. Histograms of microgastropod size for all facies of the Sinbad.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
ABSTRACT
xii
The height of the end-Permian mass extinction may have been the closest life has
ever come to complete annihilation since its origin (Erwin, 1993). It has been estimated
that 96% of species (Raup, 1979) and 57% of marine species (Sepkoski, 1986) became
extinct as a result of the Permian-Triassic crisis. The Early Triassic marine biota has an
interesting paleoecological story to tell because it is comprised of the hardy survivors of
the greatest biotic crisis in the history of life.
Biotic recoveries from mass extinctions are probably ideal settings for the
proliferation of organisms that exhibit opportunistic behavior. The eurytopy and
r-selection of opportunists makes them capable of prolific population expansion and rapid
biogeographical dispersal into stressed environments, including those characterizing mass
extinctions (Harries et ah, 1996). Therefore, it is proposed that a variety of survivors
during the biotic recovery from the End-Permian mass extinction exhibited opportunistic
behavior. The paleoecology and paleoenvironments of the Lower Triassic (Nammalian)
Sinbad Limestone Member were analyzed in detail in order to test this hypothesis.
It was determined that every Sinbad paieocommunity and every Sinbad
depositional environment is dominated by only two groups of taxa: bivalves and
microgastropods. Bivalves are a strong background signal in the Sinbad; they are found
in great abundances in every disaggregated interval and in every depositional facies of the
Sinbad Limestone Member. Microgastropods are a strong second only to bivalves
because they numerically dominate many Sinbad paleocommunities and are found
throughout every depositional environment recorded in the Sinbad. The combination of
their occurrence as ecological dominants in a variety of nearshore carbonate environments
in the Lower Triassic Sinbad Limestone Member, along with their abundant distribution
throughout Lower Triassic strata around the world (e.g., Hallam and Wignall, 1997),
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
demonstrates that microgastropods acted as biotic recovery opportunists during the
recovery from the end-Permian mass extinction.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
INTRODUCTION
Lower Triassic rocks are often described as being dead or boring, referring to their
absence of evidence for past life or, when fossils are present, the impoverished diversity of
the fauna and the very small size of the organisms (e.g., Erwin, 1993; Wignall, 2001).
Perhaps it is these reasons that have made the Early Triassic fauna seemingly less
amenable or less interesting to investigate. However, The Early Triassic marine biota
appears to have an interesting paleoecological story to tell. The Early Triassic fauna are
the hardy survivors of the greatest extinction in the history of life, the end-Permian mass
extinction. The height of the end-Permian mass extinction may have been the closest life
has ever come to complete annihilation since its origin (Erwin, 1993). It has been
estimated that 96% of species (Raup, 1979) and 57% of marine species (Sepkoski, 1986)
went extinct as a result of the Permian-Triassic crisis. The end-Permian crisis eliminated
the diverse epifaunal communities characteristic of the late Paleozoic, leaving seafloors
dominated by a few, globally-distributed, abundant survivors during the Early Triassic
(Wignall, 2001). Radiation did not begin until the Middle Triassic.
Most work performed on intervals following mass extinctions, including the
end-Permian mass extinction, has been taxonomic, quantifying the size of the mass
extinction by the loss in number of taxa or by the number of types of taxa remaining
(Droser et al, 1997; Bottjer, 2001). Relatively little has been studied on paleoecological
patterns and processes during the aftermath of the end-Permian mass extinction.
However, recent paleoecological studies indicate that the relative magnitudes of changes
measured by taxonomic diversity are not the same as the relative magnitudes of associated
ecological changes, indicating a decoupling of taxonomic and ecologic changes (Droser et
al., 1997). Collection and analysis of paleoecological data is necessary to understand a
mass extinction event’s effects upon ecological structure.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
2
As a result of the end-Permian mass extinction, the diverse epifaunal communities
characteristic of late Paleozoic seafloors were replaced by a few, globally distributed,
abundant survivors, namely bivalves and microgastropods, during the Early Triassic
(Wignall, 2001). Schubert and Bottjer (1995) determined that many of the Early Triassic
invertebrate genera are morphologically simple, unspecialized, cosmopolitan, and
opportunistic. This study was aimed at testing the hypothesis that opportunism was a
strategy used by a variety of survivors during the aftermath of the end-Permian mass
extinction. To achieve this goal, the paleoecology, diversity, abundances, and
environmental distributions of the Early Triassic (Nammalian) Sinbad Limestone Member
biota were determined, with special attention to bivalves and microgastropods. This
paleoecological study will aid in understanding the characteristics of genera and
paleocommunities during the aftermath of the end-Permian mass extinction.
PERMIAN PALEOECOLOGY
Life in Permian Seas
Permian ecosystems were fairly simple. Large, sessile, epifaunal taxa dominated
Permian seafloor communities (Erwin, 1993; Wignall, 2001). Active predators comprised
only a small part of Permian communities; most organisms were filter-feeders or passive
carnivores (Erwin, 1993). Reels composed of abundant, baffling calcareous sponges
bound by lamellar and blue-green algae are well-known throughout the Permian (Fan et
al, 1990; Hallam and Wignall, 1997). Rugosan and tabulate corals thrived until the end
of the Permian (Hallam and Wignall, 1997). Stenolaemate bryozoans are prominent
members of the Permian fauna, as were crinoid and blastoid echinoderms (Erwin, 1993).
The foraminifera are common throughout the Permian-Triassic boundary interval and
provide one of the best fossil records during this crisis (Hallam and Wignall, 1997).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
3
Ostracodes are common in many Late Penman sections and brachiopods were abundant
and diverse in all late Paleozoic marine environments. Gastropods and bivalves are
diverse and rare in Late Permian fossil assemblages. Late Palaeozoic bivalves are only
common in offshore, deep-water and/or low-oxygen settings (Jablonski, et al, 1983).
Ammonoids and nautiloids are other prominent groups during the Paleozoic (Hallam and
Wignall, 1997). Radiolarian cherts are common in deep marine sections of South China,
Japan, and Canada (Hallam and Wignall, 1997).
Permian Gastropods
Paleozoic gastropods tend to be bipectinate, slow-moving suspension-feeders or
herbivores, and frequently have little ornamentation. The dominant groups of the Upper
Paleozoic gastropod assemblages include the Eotomariidae and Phymatopleuridae (Order
Archaeogastropoda, Family Pleurotomaridae), the Pseudozygopleuridae, and the
Euomphalidae (Erwin, 1990). There was a progressive expansion in several gastropod
clades during the late Paleozoic (Erwin, 1990). Gastropod diversity doubled during the
Toumasian-Namurian, due to expanding pleurotomarid diversity (Erwin, 1990). It
increased again in the Moscovian due to an expansion of pleurotomariids and
pseudozygopleurids, then remained roughly constant until the Leonardian (Erwin, 1990)
(Figure 1). The Leonardian-Guadalupian expansion includes the Bellerophontina,
Euomphalina, Pleurotomariina, Neritopsina, Murchisonoidea, Cerithioidea, Subulitoidea,
and Heterostropha (Erwin, 1990). Gastropod genera experienced a decline during the
end-Permian mass extinction (Erwin, 1990). Most Upper Permian gastropod genera are
long-ranging with broad environmental tolerances (Batten, 1973; Erwin, 1989).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
4
Figure 1: Gastropod generic diversity from the latest Devonian to the Late Triassic.
Note the drastic decline in gastropod diversity at the end of the Permian
(modified from Erwin, 1990).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
5
J O 160-1
0 >
§ 1 4 0 -
o
E 1 2 0 ‘
100-
Q .
O
w-
C O
C O
0
80
60
! 4 C
(0
g 20'
D
Z 0
Q.
* 2 Q
Carboniferous Triassic Permian
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
N o rian
THE END-PERMIAN MASS EXTINCTION
6
Patterns of Extinction, Timing and Length of Occurrence
The marine record indicates that the end-Permian biotic crisis was induced by two
distinct extinction events separated by a period of recovery (Hallam and Wignall, 1997)
(Figures 2 and 3). The earlier extinction is dated as Late Maokouan for many groups,
including corals, bryozoans, honeycomb fusilinids, brachiopods, pectinaeean bivalves, and
ammonoids. The Phylum Blastoidea was the only higher taxonomic group to have gone
extinct; extinction during the Late Maokouan crisis is mainly at the family and genus
levels. Mostly Tethyan faunas were lost, while Boreal faunas appear to have been
oblivious to this event (Jin et al., 1994). It is evident that several major groups, including
sphinctozoans, foraminifera, bryozoans, gastropods, ammonoids, brachiopods, and
pectinaeean bivalves, radiated during the Lopingian, providing evidence that the entire
Late Paleozoic was not an era of prolonged crisis (Hallam and Wignall, 1997). The
second and greater extinction event of the Late Permian occurred during the Late
Changxingian and was a rapid, but not instantaneous, event (Hallam and Wignall, 1997).
Bowring et al. (1998) determined from biostratigraphic data from marine boundary
sections exposed in south China that the final Changxingian pulse of extinction lasted less
than 500,000 years. Many of the world’s biotic groups were diversifying almost to the
last moment of the end-Permian catastrophe (Hallam and Wignall, 1997). Uranium/lead
zircon data and statistical analysis of fossil occurrences from the Late Permian and Early
Triassic rocks from south China place the Permian-Triassic boundary at 251.4 ± 0.3
million years ago (Bowring et al., 1998; Jin et al, 2000).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
7
Figure 2: Series and stages for the mid-Permian to Middle Triassic (modified from Hallam
and Wignall, 1997).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
c
m
m
m
m
ft- 1 <0
e
«
a
XI
c
c
. to
OS ■=
C «
Jco
|h*
c
C O
m
C l
\ c
as
Ic
I e o
« l l
CD
m
m
c
< 0
'I
15
Anisian
Spathian
Smithian
Dieneriart
Griesbachian
c
(0
o
€
O
c
CO
Q.
3
«
3
C O
c
o
©
I Periods I Smrtms — 1
Changxingian
|( Dorashamian)
Wujiapingian
(Dzulfian)
Maokouan
Chihsian
STAGES
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
9
Figure 3: Figure depicting the relative fortunes of the marine biota during the
Permian-Triassic crisis. The width of each group’s column denotes the
relative change in diversity within each group and does not convey changes
in diversity between groups. Note that the nektonic and planktonic
organisms fared better than benthic organisms (modified from Hallam and
Wignall, 1997).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
b en th o s I nekton/ plankton
10
i i radiolarians
fishes/conodonts
ammonoids
■ ". ' 4 ■ i-rl i't A
ifgp- , * » ;» • • • • • • • • rr-’-'r^
I- |‘ I- J. .I- • • I I ■ . » J y . . . . . . . .
rugose corals
calcisponges
bryozoans
complex
foraminiferans
small
foraminiferans
articulate
brachiopods
echinoderms
gastropods
bivalves
V 7- V T i f t T T T I T S / T T T . T X V
i V * V tV * V i% V * |3 ,*/«*******»****%%
marine
reptiles
sc eractinians
m r m
Maokouan
Changxingian Scythian Wujtapingian
Anisian
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
11
Proposed Causes
One of the greatest ironies encompassing the End-Permian mass extinction is that,
though this extinction marked the most severe blow to life in the Phanerozoic, the exact
cause (or causes) of this event remains unknown. The old age of the rocks that record this
event contributes to the mystery: millions of years of erosion and tectonic activity have
obscured much of the geologic record of the Upper Permian and potential “smoking guns”
that could reveal definitive evidence as the cause of the end-Permian mass extinction have
been erased. Many mechanisms have been hypothesized to have caused the End-Permian
mass extinction. It might have actually been a combination of large-scale environmental
perturbations that produced the sufficient long-term global environmental stresses that
triggered the greatest extinction in the history of life (Erwin, 1993).
Before our present knowledge of plate tectonics, it was the formation of Pangea
and the coincident regression and increased seasonality that was thought to have caused
the end-Permian mass extinction (Erwin, 1993). The aggregation of continents into a
supercontinent was thought to have decreased the number of marine provinces, thereby
reducing endemism and decreasing diversity (Valentine and Moores, 1970). However,
during the Early Permian and the Late Triassic when Pangea was formed and then
reassembled, respectively, there actually was no effect on provinciality or global diversity
(Erwin, 1993). Valentine and Moores (1972, 1973) also argued that the higher
seasonality along the marine shelves characteristic of supercontinents like Pangea increases
the instability of nutrients, primary productivity, and other trophic resources. According
to this model, environmental specialists would be at a disadvantage and species diversity
should be reduced. Unfortunately, the relationship between species diversity and
environmental stability is far more complex than is accounted for in this model (Erwin,
1993).
Three not-so-popular hypothesized extinction mechanisms involve cosmic
radiation, brackish oceans, and bolide impact. The bombardment of the earth by cosmic
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
12
radiation from a nearby supernova was hypothesized by Schindewolf (1954) to have
caused the end-Permian extinction by destroying photosynthesizers. This hypothesis has
received little favor because of the lack of data and its failure to explain geochemical data
(Hallam and Wignall, 1997). The brackish oceans hypothesis postulated that the
extinction was caused by the development of low salinity oceans in the Late Permian,
based on the observation that stenohaline taxa were more heavily affected than euryhaline
groups (Beurlen, 1956). But this model also possesses several problems: the known
values of Permian salt are inadequate to produce such an effect and ammonoids, a
stenohaline group, thrived immediately after the extinction (Fischer, 1964; Benson, 1984;
Boucot and Gray, 1978). A bolide impact as the kill mechanism for the end-Permian mass
extinction seems just as unlikely. Shocked quartz has not been detected and geochemical
evidence is tenuous (Erwin, 1993; Hallam and Wignall, 1997).
The hypotheses of regression and global refrigeration are better candidates for
explaining the Late Maokouan extinctions than the cause of the terminal end-Permian
mass extinction (Hallam and Wignall, 1997). As mentioned above, the lack of
confirmation of characteristic features of major sequence boundaries and erroneous fossil
data reject the regression hypothesis as the cause of the Changxinginan extinction (Hallam
and Wignall, 1997). However, a major regression in the Late Maokouan terminated reef
formation and destroyed vast areas of shallow-marine, tropical carbonate habitats in
present-day Texas (Ross and Ross, 1995). The three lines of evidence for global
refrigeration as the cause of the end-Permian mass extinction, as championed by Stanley
(1984, 1988), were the preferential loss of tropical taxa, the gradual nature of the
extinction, and the lack of limestone formation in the post-extinction interval. Though the
Early Triassic does not seem to be characterized by these criteria, the Late Maokouan
extinction event possesses many of these attributes (Hallam and Wignall, 1997).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Knoll et a/.’s (1996) end-Permian extinction mechanism involving death by CO2
poisoning (hypercapnia) seemed at first to be a reasonable model. Knoll et al. (1996)
suggested that Late Permian oceans were anoxic and sites of organic matter burial.
Atmospheric CO2 levels would have thus been decreased and deep ocean waters would
have been enriched in by-products of organic matter mineralization, CO2 and H^S. The
CC^-rich deep waters would have been spilled onto shelf environments by the flushing of
cold water when the atmospheric concentrations of greenhouse gases decreased.
However, no available evidence indicates a cooling trend in the Late Permian (Hallam and
Wignall, 1997).
One of the most popular extinction mechanisms is the concept of a volcanic winter
(Hallam and Wignall, 1997). The Siberian Traps of western Siberia erupted an estimated
(s 1
1.5-2.5 x 10° kmr of tholeiitic flood basalts and coincided exactly with the end-Permian
mass extinction (Renne and Basu, 1991; Renne et ah, 1995). Campbell et al. (1992)
argued that the global food chain would have collapsed after vast amounts of dust and
sulfate aerosols were injected into the atmosphere and shutdown photosynthesis.
However, the nonsynehroneity between the timing of global isotopic trends and the onset
of the eruptions, the lack of evidence for a cooling event, the complete Scythian
succession of plant fossils trapped in inter-trap sediments, and the unlikelihood that the
eruptions responsible for the basalt flows were explosive enough to inject dust and
aerosols into the stratosphere all indicate that the volcanic winter hypothesis is an unlikely
one (Hallam and Wignall, 1997).
A plethora of evidence indicates warming at the end of the Permian, including a
negative oxygen isotope excursion, the replacement of cold-adapted floras by warm,
temperate floras, and the complete lack of evidence of any ice (Hallam and Wignall,
1997). The sources of CO2 required to elevate atmospheric temperatures were the
voluminous emissions of the Siberian Traps, the uplift and oxidation of glossopterid coals
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
14
of southern Gondwana during the Late Permian, and the exsolvation of methane gas
hydrates (Hallam and Wignall, 1997; Faure, et al., 1995; Erwin, 1993). However, global
warming only explains the terrestrial extinction at the end of the Permian (Hallam and
Wignall, 1997). Ocean water temperatures probably never achieved lethal temperatures.
The global warming created by the flux of CO2 into the atmosphere by coal
oxidation and Siberian Traps eruptions was the catalyst for global marine anoxia during
the latest Permian and Early Triassic, the most evidence-supported mechanism for the
end-Permian extinction (Hallam and Wignall, 1997). Evidence for anoxia in
Permian-Triassic boundary oceans includes the preferential survival of dysaerobic benthic
groups and nektic taxa and finely laminated anaerobic strata with framboidal pyrite within
boundary sections (Hallam and Wignall, 1997). Global warming would have decreased
oxygen concentrations in marine waters (because oxygen becomes less soluble in
increasing water temperatures) and the circulation of the world's oceans would have
decreased. According to Wignall and Twitchett (1996), these stagnant waters produced a
globally stratified, euxinic ocean condition in which nutrients could not circulate,
ultimately causing a crash in primary productivity. A few tens of thousands of years
would have passed before phosphorus, a limiting nutrient, would have been regenerated
from organic matter in anoxic bottom waters, causing primary productivity to bounce
back. The productivity collapse occurred at the Permian-Triassic boundary (Hallam and
Wignall, 1997). So, it was the development of oxygen-poor conditions that caused the
demise of many organisms, while the productivity collapse completely finished-off already
depauperate Permian ecosystems at the P/T boundary.
What Went Extinct
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
15
The end-Permian mass extinction was the most devastating of any mass extinction
that occurred during the Phanerozoic. The height of this extinction may have been the
closest life has come to complete extermination since its origin (Erwin, 1993). It is
estimated that as many as 96% of species (Raup, 1979) and 57% of marine families
(Sepkoski, 1986) (Figure 4) went extinct during the crisis at the end of the Permian.
More recent research on the magnitude of the end-Permian cataclysm supports
Raup’s (1979) and Sepkoski’s (1986) high estimates of biological destruction (Hallam and
Wignall, 1997). Permian reefc were terminated abruptly in the late Changxingian (Hallam
and Wignall, 1997). Twenty-one of the 30 sphinctozoan genera found in the reefs went
extinct (Wignall and Hallam, 1996); the long-ranging, conservative forms were the only
survivors (Rigby and Senowbari-Daryan, 1995). Rugosan and tabulate corals went extinct
at the end of the Permian (Hallam and Wignall, 1997). Stenolaemates, the dominant order
of bryozoans of the Paleozoic, suffered major generic-level extinctions at the end of
the Permian and the fenestrates became extinct (Taylor and Larwood, 1988). Within the
echinoderms, two crinoid subclasses and the Class Blastoidea became extinct. One genus
of cladids and one echinoid genus, Miocidaris, survived the extinction. The end-Permian
mass extinction was the worst crisis in history for the forams: the Suborder Fusilinina went
extinct, the Suborder Miliolina lost 50 % of its genera, and the Suborder Textulariina lost
33 % of its genera (Tappan and Loeblich, 1988). While deep-water, long-ranging,
cosmopolitan ostracods were unaffected by the end-Permian mass extinction (Kozur,
1991), shallow-water taxa appear to have undergone a turnover (Teichert, 1990). Ninety
percent of families and 95% of genera of articulate brachiopods became extinct in the late
Changxingian, the worst crisis in their history (Hallam and Wignall, 1997). Inarticulate
brachiopods weathered the end-Permian mass extinction unaffected (Erwin, 1993). The
end-Changxingian mass extinction wiped out 90% of gastropod genera, but only 3 of 16
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
16
Figure 4: Diversity of marine animal families through the Phanerozoic. The arrows in
the figure denote the five major mass extinctions: 1) end-Ordovician, 2)
Late Devonian, 3) end-Triassic, 4) end-Cretaceous, and P) end-Permian
(modified from Sepkoski, 1986).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
17
900
m
0)
o
u.
0
J : 300
3
2
Mesozoic Paleozoic
400 600 200
Geologic Time (10® yr)
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
18
families. A modest toll was taken on bivalves: only three families went extinct (Yin,
1985) and many familial and generic names just simply changed for many bivalves at the
boundary (Nakazawa and Runnegar, 1973). To ammonoids, the end-Permian event was
not as severe as their end-Triassic crisis or their end-Cretaceous demise (Hallam and
Wignall, 1997). No extinction has been detected in the nautiloids during the
Permian-Triassic interval (Teichert, 1990) but, on the whole, cephalopods suffered a 50%
decrease in diversity (Erwin, 1993). Radiolarian cherts abruptly disappear at the end of
the Permian (Hallam and Wignall, 1997). Trilobites had been declining since the beginning
of the Permian and finally disappeared at the end of the Permian (Erwin, 1993).
Conodonts survived the mass extinction untouched (Erwin, 1993).
THE BIOTIC RECOVERY INTERVAL
FROM THE END-PERMIAN MASS EXTINCTION
Lengths and Phases of the Post-extinction Recovery
Erwin (1993) recognizes three phases of recovery after the end-Permian mass
extinction (Figure 5). The first phase, the lag phase, was a low-diversity interval during
the Scythian when communities exhibit lower diversity and a much simpler structure than
Permian or later Triassic communities. The lag phase following the end-Permian mass
extinction, an interval of perhaps 7-8 million years (Hallam, 1991), is longer than any lag
following any other mass extinction (Erwin, 1993). The second phase of recovery, the
rebound phase, marks the end of the lag phase with the return of normal marine faunas in
the Middle Triassic. The expansion phase, the third and longest phase of the recovery
began in the Camian as diversification accelerated.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
19
Figure 5: Division of the post-extinction recovery phase into a lag phase, a rebound
phase, and an expansion phase. The rebound phase is characterized by the
return of Lazarus taxa and the expansion phase is characterized by a variety
of new groups (modified from Erwin, 1993).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Guad. T aL Seyft. W M sM | Upper
Permian Triassic Jurassic
Geologic Time
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
21
Early Triassic (Scythian) Paleoecology
Early Triassic communities exhibit low diversity and a very simple structure in
comparison to Permian or later Triassic communities (Erwin, 1993). According to Hallam
and Wignall (1997), the Scythian world was characterized by the following features: 1)
low-diversity assemblages composed of distinct Scythian lineages which included four
bivalve genera and some poorly known microgastropods and echinoderms, 2) a
cosmopolitanism of the aforementioned fauna, and 3) an absence from the fossil record of
numerous Lazarus taxa of gastropods, bivalves, brachiopods, bryozoans, calcisponges,
and calcareous algae. Of the end-Permian mass extinction, Wignall (2000) remarked that
“the crisis removed the diverse epifaunal communities characteristic of late Paleozoic
seafloors and left one dominated by a few species ofbivalve and microgastropods”. In a
pilot study inquiring about the paleoecology during the aftermath of the end-Permian mass
extinction, Schubert and Bottjer (1995) determined that many of the Early Triassic
invertebrate genera examined from three successive Early Triassic seaways, including only
a few genera of bivalves, gastropods, brachiopods, and echinoderms, were determined to
be morphologically simple, opportunistic, unspecialized and cosmopolitan.
The bivalve Claraia has been determined to be a progenitor taxon, a taxon that
appeared during the lag or rebound phase after a mass extinction (Hallam and Wignall,
1997). Rodland (1999) determined that the inarticulate brachiopod Lingula behaved as a
disaster taxon during the recovery interval after the end-Permian mass extinction, a special
type of opportunist that is geologically long-ranging and becomes unusually abundant after
mass extinctions and then returns to more restricted settings as ecological complexity
increases during the recovery interval. Marine stromatolites have been called a disaster
form after the end-Permian mass extinction (Schubert and Bottjer, 1992). The Anisian
finally marks the return of normal benthic conditions with the reappearance of most
Lazarus lineages (Hallam and Wignall, 1997).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
22
Life After the Extinction
So different are the faunas before and after the end-Permian mass extinction that
the designation of two separate eras, the Paleozoic and the Mesozoic, is warranted. The
end-Permian mass extinction triggered an explosion in marine diversity and a
reorganization in marine communities that mushroomed through the Mesozoic (Erwin,
1993). Mesozoic communities exhibit a greater number of trophic roles and more
extensive ecosystems that Paleozoic ones (Erwin, 1993). Predators are more common and
mobile, infaunal and epifaunal organisms replaced the attached, epifaunal filter-feeders of
the Paleozoic. After the demise of reefs at the end of the Permian, there was a 7-8 million
year reef gap (Fagerstrom, 1987). Reefs didn’t reappear until the mid-Anisian and are
composed of Elvis taxa that superficially resembled the Late-Permian sponge-algal reefs
(Flugel, 1994). Bryozoans began radiating during the Anisian, but the dominant Paleozoic
orders never recovered from the end-Permian crisis (Hallam and Wignall, 1997).
Echinoderms, mainly remains of crinoids and ophiuroids, are common in the Early
Triassic and consist of low-diversity Paleozoic survivors (Schubert et al, 1992). Early
Triassic radiation of forams was restricted to dysaerobic groups, like nodosariids and
textulariids (Tosk and Anderson, 1988), and it wasn’t until the Spathian and Anisian, with
the appearance of the Suborder Robertinina, when they made a major radiation (Tappan
and Loeblich, 1988). Articulate brachiopods suffered an irreversible decline in diversity
and in abundance (Erwin, 1993). Terebratulid and rhynchonellid brachiopods became
common in the Spathian (Perry and Chatterton, 1979), but bracbiopod radiation did not
take place really until the Jurassic (Dagys, 1993). Proliferation of the inarticulate
brachiopod Lingula in the Early Triassic appears to be a global pattern and has been
previously recognized as a “brachiopod macroevolutionary event” (Xu and Grant, 1992).
Ammonoids radiated rapidly in the Scythian, but were subsequently decimated by a
Spathian extinction (Yang, 1993). Radiolaria cherts reappear in the Middle Triassic after
R eproduced with perm ission o f the copyright owner. Further reproduction prohibited without perm ission.
23
7-8 million years of being absent; this absence is associated with the total extinction of all
genera and species of radiolarians (Isozaki, 1994). Conodonts experienced a rapid
diversification in the earliest Triassic (Erwin, 1993).
Early Triassic Gastropods, Microgastropods, and Bivalves
Because this study focused on the bivalves and microgastropods of the Sinbad,
they are discussed here in more detail.
In the Early Triassic, gastropods became less diverse than they are in the Late
Permian, but they are prolific and tiny (Hallam and Wignall, 1997). Gastropods
experienced less extinction during the end-Permian mass extinction than any other group
except the bivalves (Erwin, 1993). Those that survived the end-Permian mass extinction
exhibited a statistically greater geographic distribution, environmental breadth, age, and
species richness than did genera that became extinct (Erwin, 1989). Early to Middle
Triassic gastropod faunas are characterized by more Paleozoic aspects than many Late
Permian assemblages due to the new gastropod genera that appeared in the
Leonardian-Guadalupian, which gave the Guadalupian faunas a different aspect than
earlier faunas (Batten, 1973; Erwin, 1990). Many of the new Guadalupian genera were
eliminated in the extinction, hence the predominance of Paleozoic-affinity groups of
gastropods during the Induan-Anisian (Erwin, 1990). Of the Lazarus taxa that survived
the end-Permian mass extinction, gastropods are one of the best examples. Batten (1973)
noted that 32 genera and 16 families of Guadalupian affinities are found in the Ladinian
but have never been discovered in the Dzulfian or Scythian. Gastropods became rare and
attained larger sizes again in the Anisian. The Ladinian radiation of Triassic gastropod
groups finally imparted a Triassic aspect to gastropod diversity (Erwin, 1990). Triassic
assemblages were dominated by the Trochiina, Amberleyacea, and new groups of
Loxonematoidea and Pleurotomariina (Erwin, 1990). A radiation in the Camian-Norian
Reproduced with perm ission o f the copyright owner. Further reproduction prohibited without perm ission.
24
and the end-Triassic extinction finally eliminated Paleozoic gastropods and imparted a
modem look to the gastropod faunas (Erwin, 1990).
Throughout all equatorial sections, grainstones composed of millimeter-sized
microgastropod species are found (Hallam and Wignall, 1997). Batten and Stokes (1986)
have determined that these microgastropods are actually small-size species. The average
height of these microgastropods is less than 0.75 cm (Batten and Stokes, 1986). For the
purposes of this study, we define microgastropods as gastropods being one centimeter or
less in height.
In the Scythian, bivalves are abundant fossils and dominate nearly all assemblages
(Hallam and Wignall, 1997). These bivalves consist of neither Paleozoic survivors nor
groups that radiated in the Mesozoic. The genera Claraia, Eumorphotis, Unionites, and
Promyalina are found in Early Triassic marine sections around the globe and constitute
one of the most cosmopolitan faunas of all time (Hallam and Wignall, 1997). By the
Anisian, Claraia, Eumorphotis and Promyalina all went extinct and only Unionites has a
few questionable post-Scythian records.
MODERN POPULATION STRATEGIES
Opportunism (r-selection) and equilibrium situations (K-selection)
In modem ecosystems, the rate and growth of populations is determined by several
selection pressures, such as the amount of trophic resources, stresses, and competition for
food and space in the environment (Campbell, 1996). These pressures determine an
environment's carrying capacity, or, the maximum stable population size that a particular
environment can support over a relatively long period of time. Individuals and
populations use different population strategies in response to different selection pressures
(Smith, 1992).
R eproduced with perm ission o f the copyright owner. Further reproduction prohibited without perm ission.
25
There are two models of population growth (Campbell, 1996). The first model of
population growth is the logistic model. This model assumes that there is a maximum
population size that an environment can support. The rate of population growth slows as
the population approaches its carrying capacity. The second model, the exponential
model, predicts unlimited population increase under conditions of unlimited resources
(Campbell, 1996). However, these conditions are uncommon and unusual in environments.
Within the logistic model of population growth, there are two types of population
strategies (Campbell, 1996). The first of these is K-selection, also called an equilibrium
situation. K-selected organisms and populations live in stable environments, have narrow
environmental tolerances, require abundant resources, are specialized feeders, are able to
survive with prevalent competition in the environments which they inhabit, and have
population growth characterized by S-shaped curves of the logistic model of population
growth due to abundant selection pressures (Smith, 1992; Campbell, 1996) (Figures 6 and
7). K-selection favors genotypes that confer slow development, later, multiple
reproductive efforts producing few offspring each time, long lifespans, and extensive
parental care for offspring (Smith, 1992; Campbell, 1996; Stiling, 1999) (Figure 8).
K-strategists live in stable or more predictable environments in which mortality results
from density-related factors and competition is keen (Stiling, 1999). They allocate more
energy to nonreproductive activities.
The second type of population strategy within the logistic model is /--selection,
known as opportunistic behavior (Campbell, 1996). Characteristics of /--selected
organisms and populations include: the ability to colonize disturbed habitats, broad
environmental tolerances, minimal requirement for competition for food and space,
generalized feeding habits, ability to thrive in low-resource environments, and population
growth
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Figure 6: Characteristics of K-selected and r-selected organisms and populations.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
K-stratiaiste
live in stable environments
possess narrow environmental tolerances
survive prevalent competition
require abundant resources
specialized feeding habits
population growth characterized by S-shaped curve
/•-strategists
colonize temporary or disturbed habitats
possess broad environmental tolerances
require minimal competition
thrive in low-resource environments
generalized feeding habits
population growth characterized by the J-shaped curve
to
- j
28
Figure 7: Diagram of the S-sfaaped curve o f the logistic model of population growth. The
rate of population growth slows as the population approaches the carrying
capacity of the environment (modified from Campbell, 1996).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
29
number of generations
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Figure 8: Characteristics ofK -selected and r-selected individuals.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
K-stratiaists
slow development
delayed reproduction
large body size
repeated reproduction
long lifespan
extensive parental care
few offspring
/•-strategists
rapid development
earty reproduction
small body size
single reproduction
short lifespan
no parental care
many offspring
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
32
characterized by the J-shaped curve, similar to that of exponential growth, due to few
restrictions on abilities of individuals to harvest energy, grow and reproduce (Smith, 1992;
Campbell, 1996) (Figures 6 and 9). Individuals that exhibit r-selected population
strategies posses genotypes that enable them to develop rapidly, reproduce many offspring
once at an early age, usually have small body size, have a short lifespan, and provide no
parental care for their offspring (Smith, 1992; Campbell, 1996; Stiling, 1999) (Figure 8).
As a result of these qualities, r-strategists have the ability to colonize temporary or
disturbed habitats where competition is minimal (Stiling, 1999). They are able to disperse
widely and respond quickly to disturbance to the population.
K-selection and r-selection can be considered poles of a continuum from r to K
(Smith, 1992; Stiling, 1999). Under certain conditions, individuals or populations will
exhibit r-selected traits or K-selected traits. After abrupt environmental changes, like
storms or forest fires, opportunists, or r-strategists, rapidly colonize the affected area and
thrive in the high-stress and low-resource environment (Pianka, 1970). Over time, the
environment stabilizes and an equilibrium population ofK-strategists replaces the
opportunists. A weed that quickly colonizes barren land, passes through several
generations and then disappears or is completely excluded by K-selected individuals, like
trees in a mature forest, is one example of the continuum of population strategies that can
exist in environments (Stiling, 1999).
Instances of opportunistic faunas and cases of faunas consisting of equilibrium
organisms can be viewed in the modem as well as in the fossil record (Levinton, 1970).
Modem r-selected communities are characterized by low diversity and a high number of
individuals and modem K-selected communities have high diversity with low numbers of
individuals (Pianka, 1970). Opportunistic organisms and species can be identified in the
fossil record by the use of distributional and facies relations and relative abundance data
(Levinton, 1970; Bottjer, 2001). The following criteria indicate opportunistic behavior in
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
33
Figure 9: Diagram of the J-shaped curve of the exponential model of population growth.
The exponential growth model predicts unlimited population increase under
conditions of unlimited resources (modified from Campbell, 1996).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
34
— — -------->
Number of generations
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
35
the fossil record: 1) random orientation and lack of size sorting of specimens in individual
beds, but tendency for dominant species to occur in size-group aggregations (Waage,
1968), 2) distribution over a limited area, beyond which the stratigraphic horizon is
unfossiliferous (Waage, 1968), 3) aggregation of individual species in clusters, especially
if the species is sessile or stationary (Levinton, 1970), 4) presence of species in thin but
widespread isochronous horizons, indicating brief invasions (Levinton, 1970), 5) abundant
presence of a species in several otherwise distinct faunal assemblages, due to the
euiytopism typical of opportunists (Levinton, 1970), 6) great abundance of a species in a
facies with which it is not usually associated (Levinton, 1970), and 7) numerical
dominance by a species of a fossil assemblage by 85-100 % (Levinton, 1970). The
distinction between the r-selection and K-selection population strategies indicates the
stability, maturity, and degree of environmental stress in modem and fossil marine benthic
communities (Levinton, 1970).
BIOTIC RECOVERY OPPORTUNISTS
Definition of Biotic Recovery Opportunists
The characteristics of opportunists were defined from study during ecologically
stable large-scale units in the Phanerozoic history of life, or “Ecological Evolutionary
Units” (EEUs), as defined by Boucot (1983). These studies are analogous to study of
modem environments when only patches of the global environment are under high stress
or have reduced biotic complexity. However, following mass extinction events, much of
the entire world has experienced high stress, and an aftermath of reduced biological
diversity and ecological complexity follows due to prolonged stressful environmental
conditions or slow biological diversification and ecological restabilization (Schubert and
Bottjer, 1995). Therefore, the concept of “biotic recovery opportunists” is necessary.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
36
The characteristics used to detect opportunistic behavior after a mass extinction event
would be the same as those used to detect opportunism during stressful times during
EEU’s, except, in order to be called a biotic recovery opportunist, the characteristics,
patterns, and occurrences of the suspected body fossil and trace fossil assemblages must
be seen globally.
Purpose
Opportunists are persistent, common members in pre-extinction environments,
suppressed by competition from equilibrium species (Harries et al., 1996) (Figure 10).
The eurytopy and r-selection of opportunists makes them capable of prolific population
expansion and rapid biogeographical dispersal into stressed environments, including those
characterizing mass extinctions (Harries et al, 1996). Biotic recoveries from mass
extinctions are probably ideal settings for the proliferation of organisms that exhibit
opportunistic behavior. Therefore, it is proposed that a variety of survivors during the
biotic recovery from the End-Permian mass extinction exhibited opportunistic behavior.
The paleoecology, diversity, abundances, and environmental distributions of the Early
Triassic (Nammalian) Sinbad Limestone Member biota was analyzed in order to determine
the population strategies and paleoecology of one seaway during the aftermath of the
greatest extinction in the history of life.
GEOLOGIC SETTING AND PALEOGEOGRAPHY
Global Paleogeography
Late Paleozoic tectonic processes created paramount changes in the configuration
of earth’s geography. The culmination of the movement and collision of continents
destroyed several interior oceans and created widespread mountain building and
transformed a geography of dispersed continents to a geography of one gigantic landmass
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
37
Figure 10: Figure showing the relative temporal and abundance patterns for an
opportunistic species. Background environmental perturbations are
indicated by the slight population blooms above and below the hypothetical
mass extinction boundaiy. The larger peak in the interval after the mass
extinction implies more volatility in the ecological structure during the
post-extinction interval (modified from Harries et al, 1996).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Time
38
<
hypothetical
m ass extinction boundary
j ' S
Abundance
of opportunistic species
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
39
called Pangea which stretched across all latitudes, from late-Carboniferous times to the
Late Triassic (Nance and Murphy, 1994) (Figure 11). Southern Pangea consisted of
present-day South America, Africa, Arabia, India, Australia, and Antarctica and northern
Pangea comprised present-day North America, Greenland, northern Europe, and Siberia
(Francis, 1994). The Tethys Ocean cut an embayment into the eastern coastline of the
mega-continent and several small terranes in the eastern part of Pangea later assembled to
form Asia.
The formation of one supercontinent and its changing latitudinal position were
major influences on global climate from the Late Carboniferous to the Late Triassic. In
the Late Carboniferous, the majority of Pangea was situated unevenly across the equator,
with most land present in high latitudes of the Southern Hemisphere (Parrish, 1993). This
marked the onset of Gondwanan glaciation which began in western South America and
Australia and later merged with ice in South Africa and Antarctica when conditions at high
elevations at mid-high latitudes became suitable for the development of ice caps (Francis,
1994). At the same time, low latitudes in the Northern Hemisphere of Pangea were
characterized by warm, humid climates, evidenced by large coal accumulations found
during this time. Then, throughout the Permian and Triassic periods, Pangea moved north
to become equally distributed across the equator, positioning large areas of land in mid
latitudes (Francis, 1994). Mountain uplift caused by continental collision created rainfall
barriers on the eastern sides of continents. The result was a climate that became
progressively more arid with strong seasonality. Continental interiors were very arid and
rainfall was concentrated along the Tethys coastline and western coasts. Permian
evaporitic and desert environments replaced the Late Carboniferous low latitude peat
swamps (Francis, 1994). Hot, arid conditions that developed in the Permian continued
into the Triassic, when large volumes of evaporites were formed (Gordon, 1975). During
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
40
Figure 11: Global paleogeography of Pangea 250 million years ago, at the close of the
Permian (modified from Erwin, 1993).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
41
0
1
S '
IB
S. I
© <
« J
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
42
the Middle and Late Triassic Pangean climate seems to have become slightly more humid
(Francis, 1994).
Paleogeography of the Western United States
Shallow marine carbonate rocks located in the Colorado Plateau of southeastern
Utah served as the focus for this paieoecological research on microgastropods. The
Colorado Plateau is a broad, high tableland composed of many smaller plateaus and basins
that were uplifted to great elevations by mountain building forces, but remain in the
horizontal positions in which they were formed (Chronic, 1988). Its borders stretch
across Utah, Arizona, Colorado and New Mexico. Erosion of the ancestral Rocky
Mountains composes much of the Triassic sediment of the eastern portion of the Colorado
Plateau (Stokes, 1986.). To the west, the shore of the Early Triassic Pacific Ocean curved
into central Utah along a lowland that rose gently toward the Ancestral Rockies to the
east (Figure 12). Occasionally, shallow seas spread eastward across wide, marginal mud
flats, reaching far eastward from Zion National Park across the Circle Cliffs, Green River
Desert, and Uinta Basin to the central Uinta Mountains.
Moenkopi Formation
The Moenkopi Formation is composed of the Triassic reddish-brown continental
sediments eroded from the ancestral Rocky Mountains deposited on a broad flat coastal
plain (Blakey, 1974; Stokes, 1986; Hintze, 1988). This formation also contains the
Timpoweap, Sinbad, Virgin, and Shnabkaib Members, thin tongues of marine limestone
that indicate times when Early Triassic seas spread out ofNevada across the Moenkopi
terrestrial redbeds (Hintze, 1988). The Moenkopi Formation is exposed in the San Rafael
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
43
Figure 12: Generalized paleogeography during the Early Triassic in Utah. The darkest
pattern indicates areas of thicker Early Triassic sections and lighter patterns
indicate thinner Early Triassic sections. Areas denoted by the horizontal
dashed pattern are marginal marine mud flats. Remnants of the
Uncompahgre Uplift are visible in west-central Colorado (modified from
Stokes, 1986).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
44
m m
n n
mm
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
45
Swell, Teasdale Uplift, Circle Cliffs Uplift, and Monument Uplift of Utah (Blakey, 1974)
(Figure 13).
Sinbad Limestone Member
The Sinbad Limestone Member of the Moenkopi Formation represents the
easternmost extension of extensive shallow marine carbonate during the Early Triassic
(Blakey, 1974). To the west of the clastic erosion and deposition that created the
Moenkopi Formation in Utah is the Thaynes Formation, representing where carbonates
were deposited on a shallow marine shelf. The Sinbad is an eastward tongue of the
Thaynes Formation into the Moenkopi Formation (Figure 14). The Sinbad Sea is often
compared to the modern-day Trucial Coast of the Persian Gulf (Dean, 1981). The
geometry of the
Sinbad is a carbonate wedge thickening to the northwest. The Sinbad was deposited in a
variety of carbonate environments and is composed of the most diverse Early Triassic
gastropod fauna known, with 16 genera and 26 species (Batten and Stokes, 1986).
According to Batten and Stokes (1986), this microgastropod fauna is decidedly Paleozoic
rather than Mesozoic in appearance. For these reasons, five sections in the San Rafael
Swell and two sections in the Teasdale Uplift were measured and sampled in this
paleoecological study of microgastropods (Figure 15).
Three of Blakey’s (1974) facies of the Sinbad Limestone Member distinguished
upon field and petrographic studies served as the backbone for measuring and sampling
sections in the San Rafael Swell in this study. The skeletal calcarenite facies ranges from
1 1 to 24 feet thick and weathers blocky to massive (Blakey, 1974). Fossil material both
whole and abraded, including bivalves, gastropods, and echinoderms, dominate grains in
the skeletal calcarenite while scaphopods, encrusting foraminifera, pellets, ooids, and
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
46
Figure 13: Map showing the exposures o f the Moenkopi Formation in the San Rafael
Swell, Teasdale Uplift, Circle Cliffs Uplift, and Monument Uplift of the
Colorado Plateau and Utah (modified from Chronic, 1988).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
ARIZONA
PROVINCE
NEW M EX IC O
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
48
Figure 14: Figure showing the relationships of the Sinbad Limestone Member and the
Thaynes Formation from Salt Lake City to the Utah-Colorado border.
Note that the Thaynes Formation consists mainly of carbonate rocks and
the Moenkopi Formation consists mainly of red sandstones. The Sinbad
Limestone Member is a tongue of the Thaynes Formation into the
Moenkopi Formation (modified from Blakey, 1974).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Salt Lake
City, Utah
San Rafael Green River,
Swell, Utah Utah Colorado
Sinbad Limestone Member|>s j t k
M o e n k o p i
F o r m a tio n
Thaynes
Formation
carbonate
S ill redbeds
■ t * .
50
Figure 15: Map of Utah showing the San Rafael Swell and the Teasdale Uplift where
sections o f the Sinbad Limestone Member were measured for this study
(modified from Stokes, 1986).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
42 N
q .114°w 113i w idah o1 1 2 i w
< i
Q
<
2 3
o
■ 4 2 N
!1 1 1 ° W 110 °W
1 ■■nil'-i
UTAH
0
San Rafael Swell
{
Teasdale Uplift
•41 N
•4 0 ° N
8
■39 °N
38°N
ARIZONA
■37 °N
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
52
phosphate grains are also common. Terrigenous clastic grains constitute only 5 to 10
percent of the grain fraction. The skeletal calcarenite facies was probably deposited in
normal open marine conditions (Blakey, 1974). The silty peloidal calcilutite facies overlies
the skeletal calcarenite, ranges in thickness from 10 to 30 feet, and weathers platy (Blakey,
1974). Ooids, pellets, and intraclasts are the dominant nonterrigenous grain types.
Skeletal grains of poorly-preserved molluscan fragments were much less common.
Terrigenous grains constitute 5 to 40 percent of the grain fraction of this facies. The silty
peloidal calcilutite was deposited closer to shore than the skeletal calcarenite but farther
offshore than the overlying dolomitized calcarenite facies (Blakey, 1974). The
well-indurated dolomitized calcarenite is generally less than 8 feet thick and is nearly
entirely dolomite (Blakey, 1974). Grains include a skeletal fraction of less than 5 percent,
consisting of mollusk fragments, nonskeletal types including pellets, and terrigenous
material constituting 5 to 20 percent of the grain fraction. This facies was deposited in
intertidal and supratidal conditions (Blakey, 1974).
As a template for the sections measured and sampled in the Teasdale Uplift, five
of Dean’s (1981) lithofacies, distinguished by field and thin-section analyses, were used.
Lithofacies A contains five genetically related subfacies, including a stromatolitic
boundstone subfacies, an oolite-peloid packstone subfacies, a dolomicritic subfacies, a
channel conglomerate subfacies, and an evaporite subfacies, that were deposited in
intertidal and supratidal marine environments (Dean, 1981). Dean (1981) reports that
Skolithos and Arenicolites burrows are common. The skeletal packstone and pelletal
wackestone subfacies o f Lithofacies B are interpreted to represent deposition in lagoons
which lay shoreward of Lithofacies A deposition (Dean, 1981). The skeletal packstone
subfacies is characterized by skeletal material dominated by disarticulated bivalves and
gastropods that are unsorted. Lithofacies B is characterized by intense, often cyclical
bioturbation. A typical cycle reported by Dean (1981) consists o f a basal storm-surge
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
53
grainstone, overlain by an increasingly pellet-rich packstone with Skolithos burrows,
capped with up to a meter of severely bioturbated packstone or wackstone. The
homogeneous dolomitization that characterizes Lithofacies C suggests a return to
deposition in tidal-flat conditions (Demi, 1981). Lithofacies C reveals the most diverse
ichnofossils for the Sinbad Limestone Member in this area, dominated by several types of
vertical burrows and horizontal feeding trails including Planolites. The oohte-mollusk
packstone subfacies and the peloidal mudstone-wackstone subfacies of Lithofacies D
document deposition in nearly open marine conditions (Dean, 1981). The majority of
allochems in the oolite-mollusk packstone subfacies are bivalves and gastropods. Most
beds are poorly sorted with broken and abraded fragments. Dean (1981) reports that
bioturbation in Lithofacies D is concentrated in Skolithos piperock units o f about 10-20
centimeters in thickness. The well-sorted, cross-stratified grainstones of Lithofacies E
were deposited on barrier bars or shoals along the Sinbad Sea shoreline at the high-energy
interface between the lagoon and open marine shelf. Unidentified vertical burrows and
horizontal trails have been noted in Lithofacies E. Upon close examination, I believe that
the Skolithos occurrences that Dean (1981) reports are actually one limb of Arenicolites
burrows (Fraiser and Bottjer, 2001).
METHODS
To test the hypothesis that many survivors of the end-Permian mass extinction
behaved as opportunists during the biotic recovery from the end-Permian mass extinction,
all the observations and analyses performed in this study were aimed at determining if
organisms within the Sinbad dominate the paleocommunities numerically and occur in a
variety of depositional environments. The abundances and environmental distributions of
Sinbad fossils must be primary signals in order to support this hypothesis.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
54
Within the Sinbad Limestone Member of southeastern Utah, a total of seven
localities served as the basis for the field observations and laboratory work on Early
Triassic microgastropods in this study. Five localities, called Roadcut, Batten and Stokes,
Jackass Benches, Black Box, and Junction, are within the San Rafael Swell and two
localities, Fish Creek and Miners Mountain, are within the Teasdale Uplift (Figure 17).
Care was taken to ensure that each locality was at least 1 to 2 kilometers away from every
other locality to collect a broad geographical set of data.
In the field, a section was measured at each locality, from the contact at the base of
the Sinbad Limestone Member with the underlying Black Dragon Member to its contact
with the base of the overlying Torrey Member. Blakey’s (1974) and Dean’s (1980)
depositional lithofacies were recognized in the field and used as a template for these
measured sections. Intervals within the predetermined lithofacies were delineated
according to lithology and paleontology. Very fossiliferous intervals were ranked as
being: 1) microgastropod dominated (composing 60% or more of the fossil assemblage),
2) bivalve dominated (composing 60% or more of the fossil assemblage, or 3) mixed
microgastropod/bivalve assemblage (containing 40% to 60% of microgastropods and 40%
to 60% of bivalves) to obtain field observation data on the abundances o f microgastropods
in different depositional environments. Microgastropods and bivalves were the only fossils
examined for the purposes of the ranking because these fossils were by far the most
abundant skeletal remains in the Sinbad Limestone Member at these localities. Five 17.8
cm X 32 cm bags of bulk samples were removed from the top 15 centimeters o f each
ranked interval. This volume of rock was modeled after a similar study performed by
Schubert and Bottjer (1995) on the Sinbad who determined that the diversity curve
showing increase in species richness with increasing volume o f rock studied leveled off
before fossils from this sample size were fully counted. The interval of 15 centimeters
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
55
represents an attempt to collect fossils that lived as nearly at the same time as possible,
under the same environmental conditions (Schubert and Bottjer, 1995).
In the laboratory, 20 5-bag bulk samples were broken into 2 to 3 cnr pieces with
rock hammers. The fossils of the Sinbad Limestone Member are mineralogically the same
as their matrix and disaggregating the samples mechanically was the best method of
exposing as much surface area of the rock as possible for further examination of fossil
occurrences and abundances. At least two intervals from each locality, one from near the
bottom and one from near the top of the measured section, were disaggregated. Every
type of fossil in each piece of disaggregated material was recorded, counted, and its
taphonomy noted with the aid of a dissecting microscope. The percent abundances of
microgastropods and bivalves were calculated a second time for each disaggregated
interval. Trace fossils were obliterated during the disaggregation process.
Micro gastropods were regarded as “whole” if the mold or cast of the fossil was > 2/3 of
the entire shell and bivalves were regarded as “whole” if the mold or cast was > 1/2 of the
entire shell. Microgastropods < 2/3 of the entire shell and bivalves < 1/2 of the entire shell
were regarded as fragments. The bivalve count was translated into number of individuals
by dividing the number of whole valves by two. The length of each whole microgastropod
was measured with a caliper to the nearest tenth of a millimeter to determine the ratio of
“micro’ ’ gastropods versus “normal”-sized gastropods. This data was plotted in a series of
histograms and bivariate graphs that will be described and explained in the Results section.
Thin section analyses provided the best evidence as to whether or not the numbers
and environmental occurrences of fossils in the Sinbad reflect a primary signal. One thin
section was examined for each of the 20 disaggregated intervals. To eliminate bias toward
fossiliferous areas of the thin sections, each thin section was placed randomly under the
microscope three times. For each o f the three views o f the thin sections under the
microscope, the following was noted: 1) orientation and sorting of fossils, 2) aggregation
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
56
o f fossils, 3) abundance of each fossil relative to other fossils, 4) abundance of fossils in
facies with which they are usually not associated, 5) dominant fossil for each interval, 6)
mode of preservation of fossils, and 7) how the matrix that filled fossils differed from the
matrix that surrounded the fossils.
RESULTS
Stratigraphic Columns
Stratigraphic columns for each of the Sinbad Limestone Member localities were
created using both lithological and paleontological observations noted in the field and in
petrographic analyses.
San Rgfm l.Swdl. localities;
All three of the depositional facies observed by Blakey (1974), skeletal calcarenite,
silty peloidal calcilutite, and dolomitized calcarenite, are clearly observable in all San
Rafael Swell localities. The Sinbad Limestone Member's yellowish color and strong
resistance to weathering create prominent ledges throughout the San Rafael Swell.
Roadcut Locality
The Sinbad Limestone is 14.8 m thick at the Roadcut Locality and completely
exposed (Figure 16).
The skeletal calcarenite facies at the Roadcut Locality is 8.0 meters thick and was
divided into 17 intervals based on lithological characteristics and fossil content (Figure
17). The veiy basal interval at this locality is a yellowish, non-resistant, cross-bedded
peloidal packstone. Microgastropods are visible in outcrop as thin, isolated
accumulations, probably in the troughs of cross-beds. The remainder of the skeletal
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Figure 16-Photograph of the outcrop at the Roadcut Locality, Sinbad Limestone
Member. Field assistant Pedro Marenco for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
58
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
59
Figure 17-Stratigraphic column o f the Sinbad Limestone Member, Roadcut Locality. The
entire section exhibited 100% exposure. Intervals 1 - 17 are part of the
skeletal calcarenite facies, intervals 18 - 28 are part of the silty peloidal
calcilutite facies, and interval 29 represents the dolomitized calcarenite
facies. The weathering profile, rock type, fossils, and ranking that
characterize each interval are noted on the stratigraphic column. The
intervals with a circledranking indicate that a sample from that interval was
disaggregated and analyzed in the laboratory. The rankings are a
combination of field observations and laboratory analyses.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
60
1 0 m
5 m
0 m
Roadcut Locality of the Sinbad Limestone Member,
San Rafael Swell, southern Utah
• * . * /.• * v • •
yyy^yfy-y^yfy;
• v « * . *
•V * .* *v * . /
•.* , < * v .•
. • *i • •. »*. .■ ■ > •
m m m f
> .*»• .* • •. ,* « * i
■/. ' ■ J
14.8 m
rcscfta
m m m m s
^ petoidal packstone aW ty P®«oidal calcilutne
§ x | skeletal paetaton® d o to w te td eatearenita
mierite
fan iis ami aasts
t - O m ud m traciaets
Q bivalves
Qt» m ieregastropoas
OosQ m m d miefBgastteptxIfoivatw assemblage
essa> horizontal tree® fossils
U vertical trace ism ils
1 mieragastropod-deminatad interval
2 bivalve-riominttecl interval
3 mixed mierogsstfepral/bivaSv* assemblage
M ? ? ? ?
* *. • ’ » • *. • *. •* •• ♦ \ •* v ,
T
2
R eproduced with perm ission o f th e copyright ow ner. Further reproduction prohibited without perm ission
61
calcarenite consists mainly of two very different, alternating intervals. One type of interval
is characterized as being blocky, ranging from 0.26 m to 0.63 m thick, and being very
resistant to weathering (Figure 18). These intervals are skeletal packstones and are gray
in color and contain varied abundances of ooids, peloids, microgastropods, bivalves, mud
intraclasts, vertical trace fossils, and horizontal trace fossils. The other type of interval is
characteristically tan in color, micritic, cross-bedded, and contains mud intraclasts,
abundant trace fossils, and no body fossils (Figure 19). This type of interval ranges from
0.6 m to 2.18 m thick and weathers deeply between the harder skeletal packstone
intervals.
The silty peloidal calcilutite facies was differentiated from the skeletal calcarenite
facies in the field because of its decreased fossil content, increased terrigenous material
content, and its non-resistance to weathering. This facies is 2.9 m thick and alternates
between intervals of non-resistant, micrite with a high percentage of terrigenous material
and secondary gypsum to more resistant intervals with peloids, intraclasts, and very few
bivalves (Figures 20 and 21).
The dolomitized calcarenite is yellowish in color, 3.9 m thick, and very
non-resistant to weathering (Figure 22). Peloids and dolomite rhombs are visible in
outcrop and there are no apparent fossils. According to Blakey (1974), this facies is
nearly entirely dolomite.
Batten and Stokes Locality
The Sinbad Limestone is 12.5 m thick at the Batten and Stokes Locality and fairly
well exposed. Because the microgastropods that Batten and Stokes (1986) collected and
examined were from this locality, the locality was named after them.
At the Batten and Stokes locality, the skeletal calcarenite is approximately 4.5 m
thick and was divided into eight Mthological and paleontological intervals (Figure 23). The
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
62
Figure 18-Photograph of the resistant skeletal packstone of interval 10, Sinbad
Limestone Member, Roadcut Locality. Note the mud intraclasts in this
photo. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
63
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
64
Figure 19-Photograph of a typical, non-resistant mudstone found in the skeletal calcarenite
facies, Sinbad Limestone Member, Roadcut Locality. Note the vertical
bioturbation. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
65
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission
66
Figure 20-Photograph of non-resistant, micritic intervals with secondary gypsum typical
of the silty peloidal calcilutite facies, Sinbad Limestone Member, Roadcut
Locality. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
67
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
68
Figure 21-Photograph of typical mud intraciasts found in the more resistant intervals of
the silty peloidal calcilutite facies, Sinbad Limestone Member,
Roadcut Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
70
Figure 22-Photograph of the massive dolomitized calcarenite facies, Sinbad
Limestone Member, Roadcut Locality. Note the tabular cross-bedding.
Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
72
Figure 23-Stratigraphic column of the Sinbad Limestone Member, Batten and Stokes
Locality. Intervals 1 - 8 are part of the skeletal calcarenite facies, intervals
9 -15 are part of the silty peloidal calcilutite facies, and Interval 16
represents the dolomitized calcarenite facies. The weathering profile, rock
type, fossils, and ranking that characterize each interval are noted on the
stratigraphic column. The intervals with a circled ranking indicate a sample
from that interval was disaggregated and analyzed in the laboratory. The
rankings are a combination of field observations and laboratory analyses.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
73
5 m
0 m
Batten and Stokes Locality of the Sinbad Limestone Member,
San Rafael Swell, southern Utah
©
O
©
S3
> Q
!Qooo
l i t h n l o a i a s
peloidal packstone silty pelkwlsl eatciiutita
skeletal packstone dolomitized calcarenite
fossils and plssfs
wad intradasts
Q bivalve®
009 microgastropods
OwS mixed miaogaswojBodtetvalv® assemblage
y vertical trace fossils
• ammonoids
rankino
1 microgastropod*dominatsd interval
2 bivalve-dominated interval
3 mixed microgastropod/hivatvs assemblage
12.5 m
m s s m
r n - 1
g g g g g g g i
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
74
skeletal calcarenite consists of a lower peloidal wackestone interval and alternating
intervals of skeletal packstones and mudstones. The lower peloidal wackestone is 0.84 m
thick, yellowish in color, and very non-resistant. Microgastropods and mud intraclasts are
concentrated in the troughs of cross-beds (Figures 24 and 25). Many microgastropods are
visible in talus along the slopes of the outcrop (Figure 26). The skeletal packstone
intervals range from 0.39 to 0.92 m thick and weather into blocky ledges (Figure 27).
Skeletal material consists mainly of bivalves aligned horizontally or packed nearly
vertically into fen-like displays. A few gastropods were visible in outcrop and some
ammonoids were found in talus. Less resistant mudstone intervals range from 0.27 to
0.87 m thick and alternate with the skeletal packstone intervals (Figure 28). This type of
interval is very finely laminated and is mainly absent o f fossils, although interval 3 does
contain bivalve fragments (Figure 29).
The silty peloidal calcilutite fecies is a 4.2 m thick slope-former and a great deal is
covered by talus. This fecies consists of alternating intervals of very non-resistant,
unfossiliferous mudstone with slightly more resistant, peloidal layers with rare fragments
of bivalves, like those seen in the silty peloidal calcilutite at the Roadcut Locality (Figures
29 and 30).
The dolomitized calcarenite is 3.8 m thick at this locality and weathers into a
massive, blocky ledge. Cross-bedding is obvious in the field and there appear to be no
fossils (Figure 31).
Jackass Benches Locality
Numerous donkeys seen grazing a grassy area surrounded by Sinbad Limestone
Member ledges in this area give this locality its name (Figure 32). Most o f the 13.5 m
thick Sinbad is exposed at this locality, but some intervals are nearly completely covered
by talus (Figure 33).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
75
Figure 24-Photograph of the lower peloidal wackstone of the skeletal calcarenite facies,
Sinbad Limestone Member, Batten and Stokes Locality. Microgastropods
appear in this photo as somewhat round cavities that follow the
cross-bedding. Note the abundance of microgastropods concentrated in
the cross-bedding. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
77
Figure 25-Close-up photograph of the microgastropods concentrated in the cross-bedding
of the lower peloidal wackestone of the skeletal calcarenite fecies, Sinbad
Limestone Member, Batten and Stokes Locality. Arrows point to two
accumulations of microgastropods.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
79
Figure 26-Photograph of several microgastropods in float from the lower peloidal
wackestone o f the skeletal calcarenite fecies, Sinbad Limestone Member,
Batten and Stokes Locality. Note the high-spired microgastropod in the
upper right comer of the photograph. U. S. dime for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
8 1
Figure 27-Photograph of intervals 4, 5, and 6 of the skeletal calcarenite fecies,
Sinbad Limestone Member, Batten and Stokes Locality. Intervals 4 and 6 are
resistant skeletal packstones and Interval 5 is a non-resistant mudstone that
weathers between the skeletal packstones. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
82
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
83
Figure 28-Close-up photograph of the fine laminations typical of the mudstones of the
skeletal calcarenite fecies, Sinbad Limestone Member, Batten and Stokes
Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
85
Figure 29-Photograph o f typical non-resistant, more micritic intervals of the silty peloidal
calcilutite facies, Sinbad Limestone Member, Batten and Stokes Locality.
Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
87
Figure 30-Photograph showing the typical alternation of non-resistant, more micritic
intervals overlain by more resistant, peloidal intervals characteristic of the
silty peloidal calcilutite, Sinbad Limestone Member, Batten and Stokes
Locality. Arrow points to resistant layer. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
89
Figure 31-Photograph of the dolomitized calcarenite facies, Sinbad Limestone
Member, Batten and Stokes Locality. Note the massiveness of this facies
and the cross-bedding.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Figure 32-Photograph of a donkey at the Jackass Benches Locality, Sinbad
Limestone Member. The Sinbad Limestone Benches (top of ridge
background) and the jackasses give this locality its name.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
93
Figure 33-Photograph of the outcrop at the Jackass Benches Locality, Sinbad
Limestone Member. Most of the Sinbad is exposed here, but there are
some covered intervals.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
95
The characteristics of the skeletal calcarenite at Jackass Benches are very similar to
those at the Roadcut and Batten and Stokes Localities (Figure 34). The lower, resistant,
yellow peloidal wackestone is 0.57 m thick and contains discrete horizontal accumulations
of microgastropods throughout the entire interval that seem to follow cross-bedding
(Figures 35 and 36). A 0.19 m thick interval containing mud intraclasts ranging from 1
mm to 3.5 cm in length occurs above interval 2. Like the other previously mentioned San
Rafael Swell localities, the remainder of the skeletal calcarenite consists of alternating
intervals ofblocky skeletal packstones and non-resistant mudstones. Bivalves are the
most abundant fossil in the skeletal packstone intervals and are aligned horizontally and
parallel to each other. In some bivalve-dominated intervals (Figure 34), all of the bivalves
are aligned convex side up (Figure 37). Microgastropods and ammonoids were also found
in the skeletal packstone intervals (Figures 38 and 39). The mudstone intervals found
between the skeletal packstone intervals are very non-resistant and rarely contain body
fossils.
The silty peloidal calcilutite is 5.2 m thick at the Jackass Benches Locality. This
facies was recognized in the field by the abundant peloids visible in outcrop, the lack of
fossils, and its slope-forming nature. So much of this facies is covered by talus that it was
lumped into one interval. In small areas of the outcrop that were not covered by talus,
cross-bedding was observed (Figure 40).
The lower 1.6 m portion of the dolomitized calcarenite facies at this locality
contains no fossils, is very non-resistant, and contains herringbone cross-stratification
(Figure 41). Above this interval is a 0.21 m thick oolitic wackestone that contains
bivalves and microgastropods. The contact between the oolitic wackestone and the
dolomitized calcarenite is very clear (Figure 42).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
96
Figure 34-Stratigraphic column o f the Sinbad Limestone Member, Jackass Benches
Locality. Intervals 1 - 8 are part of the skeletal calcarenite facies, Interval
9 represents the silty peloidal calcilutite fecies, and Intervals 10-11
represent the dolomitized calcarenite fecies. The weathering profile, rock
type, fossils, and ranking that characterize each interval are noted on the
stratigraphic column. The intervals with a circled ranking indicate a sample
from that interval was disaggregated and analyzed in the laboratory. The
rankings are a combination of field observations and laboratory analyses.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
97
10 m ■
m m .
* * . • ’.* * .* * . *
■ > ; y ; y ; y ; y ; y ; y ; -
wy&y&yy
• . • » i * . « . * « • • ■ •
...... •’ . * - ' . • • * . • * * . . *
•
Xy&y&Xyy
V A v V A ^ A 'A V
• . * * . • * . • • . > ' * V *
/:v«v.*v:v:v:v*.
• .••• .*,• .*. * .* ,■
* . • •. • * . • • •, • •. • * . i
w m m
c * v -
• • .* *.• • * . * < * .
♦ •• • . ■ .* • .■ • .* • . • . • i
• • .* • . * < •* .* • > • . * •* .*
V-'V/VA vV A v\v'
V V - A V c V - .v V V .- V
r n r n m
5 m •
Jackass Benches Locality of the
Sinbad Limestone Member,
San Rafael Swei, southern Utah
I peloidal w a ck esto n ej^ ^ silty pelioidai calcilutite
J j skeletal packstone R < 3 dolomitaed calcarenite
! mierite
oolitic wackestone
fassMajmS dusts
r-^1 mud intradasts
Q bivalves
Oo» microgastropods
OodS mams mierogastropod/bivahm assemblage
# ammonoNSs
1 mtcrogastropod-dominatsd interval
2 bivalve-dominated interval
3 mixed moogastropedfoivafve assemblage
0 m
©
13.5 m
r o l o io lo i o !
i
1 2 3
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
98
Figure 35-Photograph of the microgastropod-containing lower peloidal wackestone
interval of the skeletal calcarenite fecies, Sinbad Limestone Member,
Jackass Benches Locality. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
1 0 0
Figure 36-Close-up photograph of a discrete horizontal accumulation of microgastropods
in the lower peloidal wackestone of the skeletal calcarenite facies Sinbad
Limestone Member, Jackass Benches Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
1 0 2
Figure 37-Photograph of a typical bivalve-dominated skeletal packstone of the skeletal
calcarenite facies, Sinbad Limestone Member, Jackass Benches Locality.
Note the bivalves are nearly all aligned parallel to each other, convex-side
up. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
104
Figure 38-Photograph of a typical skeletal packstone interval of the skeletal calcarenite
facies, Sinbad Limestone Member, Jackass Benches Locality. This interval
contains abundant microgastropods and bivalves. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
106
Figure 39-Photograph of an ammonoid from the float of a skeletal packstone interval of
the skeletal calcarenite fecies, Sinbad Limestone Member, Jackass Benches
Locality.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission
108
Figure 40-Photograph of the exposed portion of the silty peloidal calcilutite facies, Sinbad
Limestone Member, Jackass Benches Locality. Note the cross-bedding.
Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
110
Figure 41-Photograph of the doloimtized calcarenite facies, Sinbad Limestone Member,
Jackass Benches Locality. Note the cross-bedding and the massiveness of
this interval. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
112
Figure 42-Photograph of the contact of the oolitic wackestone interval and the underlying
dolomitized calcarenite facies, Sinbad Limestone Member, Jackass Benches
Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
113
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
114
Black Box Locality
The Sinbad Limestone Member is very well exposed along both sides of a wash at
the Black Box Locality (Figure 43). All three of Blakey's (1974) depositional facies are
obvious in outcrop.
The basal peloidal wackestone o f the skeletal calcarenite is very similar to the basal
skeletal calcarenite intervals at the other San Rafael Swell exposures of Sinbad Limestone
(Figure 44). This interval is 1.0 m thick and contains microgastropods and mud
intraclasts that are concentrated in the troughs of cross-bedding (Figures 45 and 46). Also
like the other San Rafael Swell localities, the skeletal calcarenite at the Black Box locality
alternates between hard, fossiliferous wackestones and packstones and soft,
non-fossiliferous mudstones. One difference between the skeletal calcarenite of this
locality from the other localities is that here there are fewer mudstone intervals and a
greater diversity and abundance of fossils in the packstones and wackestones (Figures 44
and 47). The skeletal wackestones and skeletal packstones contain numerous
microgastropods, bivalves stacked horizontally on top of each other, mud intraclasts,
ammonoids, scaphopods, and horizontal and vertical trace fossils (Figure 48).
The first interval in the silty peloidal calcilutite is a fossil-lacking mudstone with
convoluted bedding (Figure 49). The interval above this interval contains tabular and
hummocky cross-bedding (Figure 50). The next nine intervals are only a few centimeters
thick each and alternate between very non-resistant intervals and more resistant intervals
that contain bivalves, microgastropods, and horizontal trace fossils (Figures 44, 51, 52 and
53).
The dolomitized calcarenite caps the Sinbad at the Black Box Locality and is no
different here than from the other San Rafael Swell localities. It contains no fossils and
reveals a variety of cross-bedding structures (Figure 54).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Figure 43-Photograph of the outcrop at the Black Box Locality, Sinbad Limestone
Member.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
117
Figure 44-Stratigraphic column of the Sinbad Limestone Member, Black Box Locality.
Intervals 1 - 17 are part of the skeletal calcarenite facies, intervals 18 - 27
are part o f the silty peloidal calcilutite facies, and Interval 28 represents the
dolomitized calcarenite facies. The weathering profile, rock type, fossils,
and ranking that characterize each interval are noted on the stratigraphic
column. The intervals with a circled ranking indicate a sample from that
interval was disaggregated and analyzed in the laboratory. The rankings
are a combination of field observations and laboratory analyses.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
118
T O m
5 m
0 m
&
Black Box Locality o f the Sinbad Limestone Member,
San R a f a e l Swell, southern Utah
13.5 m
mist«s
JUsH pdoidai wackmton* | j | | | *i«y peikxctal catcituwe
m sim dotomtated cstcarente
j g g atotetat BtectatBSanaa and gactetone
tente aretan iw
mud immdam
Q txm lvm
Oo° micragasMpods
OsG nnM m sm gm rspsm m & m asaem btas®
«sj aeapheptxls
ttsas hotteonlai t
bbM m
1 moogastropod-dominated interest
2 tetrahte-dommated interest
3 mixed irocrogastrapod/bivalws assemblage
“T "
2
I
3
R eproduced with perm ission of th e copyright ow ner. Further reproduction prohibited without perm ission.
119
Figure 45-Photograph of the basal peloidal wackestone of the skeletal calcarenite facies,
Sinbad Limestone Member, Black Box Locality. Note the
microgastropods that follow the cross-bedding. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
121
Figure 46-Close-up photograph of microgastropods and mud intraclasts of the basal
peloidal wackestone of the skeletal calcarenite facies, Sinbad Limestone
Member, Black Box Locality. Note how the microgastropods and mud
intraclasts follow cross-bedding. Field of view is approximately 15 cm
from top to bottom of the photograph.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
123
Figure 47-Photograph of the numerous skeletal packstones and skeletal wackestones that
characterize the skeletal calcarenite facies o f the basal peloidal wackestone
of the skeletal calcarenite facies, Sinbad Limestone Member, Black Box
Locality. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
125
Figure 48-Photograph o f the cross-section of a partially dissolved away ammonoid found
in a skeletal packstone interval of the skeletal calcarenite facies, Sinbad
Limestone Member, Black Box Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
127
Figure 49-Photograph of the convoluted bedding found in the first interval of the silty
peloidal calcilutite facies, Sinbad Limestone Member, Black Box Locality.
Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
129
Figure 50-Photograph of the tabular and hummocky cross-bedding found in Interval 19 of
the silty peloidal calcilutite facies, Sinbad Limestone Member, Black Box
locality. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
131
Figure 51-Photograph of Intervals 19-25 of the silty peloidal calcilutite facies, Sinbad
Limestone Member, Black Box locality. Rock hammer for scale. This
photograph shows the alternation between very non-resistant intervals and
more resistant intervals. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
133
Figure 52-Photograph of horizontal trace fossils found in Interval 26 o f the silty peloidal
calcilutite facies, Sinbad Limestone Member, Black Box locality. Rock
hammer for scale. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
135
Figure 53-Photograph of a high-spired microgastropod found in Interval 28 of the silty
peloidal calcilutite facies, Sinbad Limestone Member, Black Box locality.
Rock hammer for scale. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
137
Figure 54-Photograph depicting the cross-bedding and the massiveness of the dolomitized
calcarenite facies, Sinbad Limestone Member, Black Box locality. Rock
hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
139
Junction Locality
Of the seven Sinbad Limestone Member localities examined in this research
endeavor, the Junction Locality is the most poorly exposed (Figure 55 ).
Though much of the outcrop at the Junction Locality is covered by talus, it is
apparent that the skeletal calcarenite here closely resembles the skeletal calcarenite at the
other San Rafael Swell localities (Figure 56). In the 1.5 m thick basal peloidal wackestone,
microgastropods, bivalves, intraclasts, and cross-stratification were visible in outcrop
(Figure 57). The next seven intervals alternate between the already familiar fossiliferous
packstone and non-fossiliferous mudstone intervals (Figure 58). The skeletal packstone
intervals range from 0.22 to 3.0 m thick, are very resistant to weathering, and contain
varying abundances of bivalves, microgastropods, and scaphopods. The 0.95 to 0.21 m
mudstone intervals are fossil-free and weather bulbously in between the more resistant
skeletal packstone intervals. In addition, interval 3 is a 1.9 m thick interval that looks
much like the intraclast-bearing interval at the Jackass Benches Locality in that it contains
mainly intraclasts that range from 0.5 mm to 1.3 cm.
The silty peloidal calcihrtite is a slope-forming, unfossiliferous, 5.0 m thick interval
at the Junction Locality. Cross-bedding is visible in outcrop (Figure 59).
At the Junction Locality, the dolomitized calcarenite facies is 1.2 m thick and very
non-resistant to weathering. No fossils are evident in outcrop, but cross-stratification is
obvious in outcrop (Figure 60).
Teasdale Uplift Localities
Dean's (1980) five depositional lithofacies A, B, C, D, and E were used as a
framework for measuring sections at the Teasdale Uplift localities. The contrast of the
Sinbad Limestone’ s resistant yellow ledges with the redbeds characteristic o f southern
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
140
Figure 55-Photograph of the outcrop at the Junction Locality of the Sinbad Limestone
Member, located in the San Rafael Swell, southern Utah.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
142
Figure 56-Stratigraphic column of the Sinbad Limestone Member, Junction Locality.
Intervals 1 - 8 are part of the skeletal calcarenite facies, Interval 9
represents the silty peloidal calcilutite facies, and Interval 10 represents the
dolomitized calcarenite facies. The weathering profile, rock type, fossils,
and ranking that characterize each interval are noted on the stratigraphic
column. The intervals with a circled ranking indicate a sample from that
interval was disaggregated and analyzed in the laboratory. The rankings
are a combination of field observations and laboratory analyses.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
143
Junction Locality of the Sinbad Limestone Member,
San Rafael Swell, southern Utah
10 m -
• • * • * * . • • * . * • * . ' • * . *
* . * • * . « * . • * . • » . • * . * . • .
■ . •'/. * . • * . * • . * \
• • * . * • ' . * • . * • . *
* . • • . * * . * * . • ■ . • • • • •.»
fc« . * .
« . * . •/. * .
• • * . ’ . * . • .* .*
* . • • V • . \ • * . • • »
• . • * * . • • • » % • * • *
•. * * . • •, • \ • * •. • •. • \ i
V; .V;
* • \ * • . * « • • <
. * • - ■ • / • .• • .• • . * • .• ■
• * . * * * . ■ -v . * . * .*.• .* ,•
• • ’ . * • * . * • * * • •
5 m
• V * • • • . * * * . * • V V
^ * V - s v * V -
• • • • « • * . * • , * * . ■ * . • * . • 1
• . * , * • .* . ♦ .*;•.»n
* . • • * . ■ • - • * . > •,» % »
* ,* . * . * ♦ *.’ • * . * . •
* • * . » * * . * * . * • ’. *
'.’ - v
V = V = V / V . \ V . : V . - , V . :
* .* • : • .* * .* • .♦«.• • .*'
• • . « . * * .• ■ » ;
■ » * . * • • * ■ * * . * « * .
,• * .• * . « * .; • * . .• ■
• * • . * • . * ' / • / • . * • . *
•
0 m
tohotnowts
p aM iat waekssson® B iK y p sitaS al catcihitite
micrts® ao!om ’ ,i2w3 estearenn®
sto te tg i pactesoiw
m>sS im rscStsts
Q b iv a lm
Ooe m ieroesstfop od s
O aQ m ixed micmgM Sropod/bwalv* essem M age
-=» scaph op od s
ranktnn
1 m icrogasSropod-dom m atse! m tereai
2 bivalve-dominated interval
3 m ixed m icrogastropod/bivalve assem b lage
12.3 m
(to)
5
3
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
144
Figure 57-Photograph depicting the cross-stratification visible in the exposure of the basal
peloidal wackestone of the skeletal calcarenite facies Sinbad Limestone
Member, Junction Locality located. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
146
Figure 58-Photograph depicting the alternating resistant skeletal packstone intervals with
non-resistant, non-fossiliferous mudstone intervals that characterize the
skeletal calcarenite facies, Sinbad Limestone Member, Junction Locality.
Arrow points to non-resistant layer. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
148
Figure 59-Photograph of the cross-bedding visible in the outcrop of the silty peloidal
calcilutite facies, Sinbad Limestone Member, Junction Locality. Rock
hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
150
Figure 60-Photograph of the cross-bedding visible in the outcrop of the dolomitized
calcarenite facies, Sinbad Limestone Member, Junction Locality. Rock
hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
152
Utah and the Teasdale Uplift made it easy to trace the Sinbad for miles and to find
well-exposed localities.
Fish Creek Locality
The outcrop of the Fish Creek Locality is very well-exposed (Figure 61).
Twenty-four intervals were delineated from Dean's (1980) five lithofacies (Figure 62).
The first interval of Lithofacies A is believed to be part of the dolomicrite
subfacies, as defined by Dean (1981). This interval is 1.7 m thick, massive, ledgy, and is
described as having a cryptalgal bedding style (Figure 63). High-spired gastropods, up to
3 cm in length are found only at the very top of this interval (Figure 64). Abundant
bivalves are also present (Figure 65). Intervals 2 - 5 are part of the oolite-peloid
packstone subfacies. These intervals contain common horizontal and vertical trace fossils
(Figures 66 and 67). Microgastropod and bivalve fragments are also abundant in these
intervals.
The skeletal packstone and pelletal wackestone subfacies o f Lithofacies B were
both found at the Fish Creek Locality (Figure 62). The fossil material in the skeletal
packstone intervals includes various quantities of microgastropods, bivalves, ammonoids,
and vertical bioturbation (Figure 68). The pelletal wackestones contain some vertical
bioturbation (Figure 62). Intervals 12 and 14 are very intensely bioturbated and contain
bivalves and ammonoids (Figure 69).
Lithofacies C, nearly completely dolomite, is 2.8 m thick and forms a deep recess
between Lithofacies B and D (Figures 62 and 70). Abundant, distinct vertical and
horizontal trace fossils are observed in the field.
Dean's (1980) oolite-mollusk packstone and peloidal mudstone-wackestone
subfacies were observed in Lithofacies D. The fossils of the oolite-mollusk packstone
intervals include microgastropods, bivalves, and vertical and horizontal trace fossils
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Figure 61-Photograph of the outcrop at the Fish Creek Locality of the Sinbad Limestone
Member, Teasdale Uplift, southern Utah.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
154
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
155
Figure 62-Stratigraphic column of the Sinbad Limestone Member, Fish Creek
Locality, Teasdale Uplift, southern Utah. Intervals 1 - 5 are part of
Lithofacies A, Intervals 6 -1 4 are part of Lithofacies B, Interval 15
represents Lithofacies C, Intervals 16 - 21 are part o f Lithofacies D, and
Intervals 22 - 24 represent Lithofacies E. The weathering profile, rock
type, fossils, and ranking that characterize each interval are noted on the
stratigraphic column. The intervals with a circled ranking indicate a sample
from that interval was disaggregated and analyzed in the laboratory. The
rankings are a combination o f field observations and laboratory analyses.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
156
Fish Creek Locality of the Sinbad Limestone Member,
Teasdale Uplift, southern Utah
10 m
5 m
0 m
UOO0 a o o
timotooies
□ tM sm e tm with oyptsieai MMng
j oofcw-pelokl pactttone
■
al paeMon«iwaeiiestoM
19.6 m ■
(22]
15 m
' / S S S S S S ,
< < < < < < < «
g M
« « « « <
SSC j£<<<
£>>v£>v
ptH U I wachaicne|-.y
eoBte-mellusfc packstone
pataMai mtspstonehaachestone
E3 M oniitm tt psanistone
t^£ ) mud M a d a m
Q fcswSws
Ow m iaopsarapods
OwO misad tnteogasmspoatoiwh® assemblage
• anmeneitSs
ite=s horizontal ra c e te siis
U vertical epos M k
mate
1 moogastrepod-clofninated (Mental
2 bhmve-dominMed interval
3 mixed mtcieeastiepetSfoivaive assemblage
R eproduced with perm ission of the copyright ow ner. Further reproduction prohibited without perm ission
157
Figure 63-Photograph of the cryptalgal bedding style characteristic of Interval 1 of
Lithofacies A, Sinbad Limestone Member, Fish Creek Locality. Rock
hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
158
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
159
Figure 64-Photograph o f large, high-spired gastropods found on a bedding plane at the
very top of Interval 1 of Lithofacies A, Sinbad Limestone Member,
Fish Creek Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
160
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
161
Figure 65-Photograph showing the abundance of bivalves in Interval 1 of Lithofacies A
Sinbad Limestone Member, Fish Creek Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
163
Figure 66-Photograph of a bedding plane showing abundant horizontal trace fossils and
the openings o f vertical trace fossils characteristic of the oolite-peloid
packstone subfacies of Lithofacies A, Sinbad Limestone Member,
Fish Creek Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
164
f
V ' „ ' - f ^ * J T * * * *
- . - * « * « -
m m
'■iiip
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Figure 67-Photograph of vertical trace fossils found in the oolite-peloid packstone
subfacies of Lithofacies A, Sinbad Limestone Member, Fish Creek
Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
166
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
167
Figure 68-Photograph of vertical trace fossils and mircrogastropods occurring together in
the skeletal packstone subfacies of Lithofacies B, Sinbad Limestone
Member, Fish Creek Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
169
Figure 69-Photograph of Interval 12 of Lithofacies B, Sinbad Limestone Member, Fish
Creek Locality. This interval has been so intensely bioturbated that it
weathers crumbly. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Figure 70-Photograph of Lithofacies C, Sinbad Limestone Member, Fish Creek Locality.
Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
173
(Figure 71). No body fossils were observed in the peloidal mudstone interval, but it is
well-bioturbated.
Intervals 22 - 24 make up the dolomitized grainstones Lithofacies E (Figure 72).
Interval 22 is a 1.0 m thick slope-former of ripple-bedded oolite grainstones that lack
fossils. Interval 23 is different from Interval 22 only in that no ooids are visible in
outcrop. Interval 24 forms a 0.80 m thick ledge containing ooids and no fossils.
Dean's (1980) Lithofacies F of greenish gray dolomitic claystones is completely
covered at the Fish Creek Locality.
Miners Mountain Locality
The Sinbad Limestone Member is exposed at the Miners Mountain Locality in a
rain-washed gully. Many of the non-resistant intervals are nearly completely covered or
eroded away.
Much of Lithofacies A is covered at the Miners Mountain Locality. Interval 1
belongs to Dean's (1980) dolomicrite subfacies (Figures 73 and 74). This interval exhibits
a cryptalgal bedding style, has no apparent fossils, and forms a prominent ledge. Interval
2 is mostly covered by talus but is thought to belong to the oolite-peloid packstone
subfacies (Figure 75). Intervals 3 -10 are also parts of the oolite-peloid packstone
subfacies, but they each contain variable amounts of microgastropods and bivalves.
Intervals 11-17 represent Lithofacies B (Figure 73). Intervals 11,13,15, and 17
are non-resistant, contain abundant microgastropods and bivalves, and make up the
skeletal packstone subfacies. Intervals 14 and 16 contain bivalves and are crumbly due to
intense bioturbation.
Lithofacies C is 2.2 m thick and contains large amounts of horizontal and vertical
trace fossils (Figure 73).
Both the oolite-mollusk packstone and peloidal mudstone-wackestone subfacies
were observed in Lithofacies D at the miners Mountain locality (Figure 73). The
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
174
Figure 71-Photograph of vertical trace fossils found in the oolite-mollusk packstone
subfacies of Lithofacies D, Sinbad Limestone Member, Fish Creek
Locality. Lens cap for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
176
Figure 72-Photograph of the dolomitized grainstones of Lithofacies E, Sinbad Limestone
Member, Fish Creek Locality. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
178
Figure 73-Stratigraphic column of the Sinbad Limestone Member, Miners Mountain
Locality, Teasdale Uplift. Intervals 1 - 10 are part of Lithofacies A,
Intervals 11 -17 are part of Lithofacies B, Interval 18 represents
Lithofacies C, intervals 19 - 27 are part of Lithofacies D, and Interval 28
represents Lithofacies E. The weathering profile, rock type, fossils, and
ranking that characterize each interval are noted on the stratigraphic
column. The intervals with a circled ranking indicates that a sample from
that interval was disaggregated and analyzed in the laboratory. The
rankings are a combination of field observations and laboratory analyses.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
Figure 73 (continued)-
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Miners Mountain Locality of the Sinbad Limestone Member,
Teasdate Uplift, southern Utah (continued)
181
i M f i i i i i s s
□
d o t o m i e r a t ® with cryptalgal
E l o o i $ i @ ^ 3 ® io i d packstone
t ig pefieta) wacfcstor*
oeStta-moltek pgeksttme
E 3 pateidal mudstonatovacfcaston®
E 3 «totomftiz«J granistoft©
mufl mtradasts
Q Iwalv®*
Ooo merogastropDCla
O o£} noses mtemgaatrepwltowalv® assemblage
-ea> scapiiopeiSs
# ammenotd®
o tss honzonial trass fossils
y vertical trace
t mierogastropotf-tJraranaied intsnral
2 twelve • dominated intaival
3 miasrf mietogastfepoMvaive asMfttbiags
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
^
182
Figure 74-Photograph of the cryptalgal bedding style characteristic of Interval 1 of
Lithofacies A, Sinbad Limestone Member, Miners Mountain Locality.
Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
184
Figure 75-Photograph of the oolite-peloid packstone subfacies of Lithofecies A, Sinbad
Limestone Member, Miners Mountain Locality. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
185
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
186
oolite-mollusk packstone subfacies contains abundant xnicrogastropods and bivalves. The
peloidal mudstone-wackestone subfacies contains very abundant and distinct vertical trace
fossils (Figure 76).
Lithofecies E is represented by a 1.8 m thick ledge that contains peloids and rare
bivalves and gastropods (Figure 73).
Lithofacies F, as recorded by Dean (1981), was not noted at this locality.
Petrology and Taphonomy
Rock identification and percentage abundances of skeletal and non-skeletal
fragments for each thin section are available in Appendix A.
San Rqfael Swell Localities
Two thin sections, one each from Intervals 1 and 8, were examined from the
Roadcut Locality. Interval 1 is a peloidal packstone. The allochems include 0.25 mm
wide peloids and ooids encircled with equant sparry cement (Figure 77). The
intergranular matrix is equant sparry cement. Hematite occurs as stains on the allochems
and the intergranular matrix. Interval 8 isa skeletal packstone. Skeletal allochems
include: 1) abundant fragments of bivalves and some whole bivalves 1-4 mm long, and
2) broken and whole microgastropods about 1 mm in length (Figure 78). All the skeletal
allochems have been neomorphosed to equant spany calcite. The voids within the
microgastropods have been filled with micrite. Peloids are the non-skeletal allochems
present and are encircled by equant sparry cement and have hematite stains. Intergranular
matrix consists of micrite and microgranular calcite.
Thin sections from Intervals 1 and 6 were examined from the Batten and Stokes
Locality. Interval 1 is a peloidal wackestone whose allochems are mainly peloids and
ooids 0.2 - 5 mm wide. Clots, or ghosts of peloids, 1 mm wide filled with dolomite
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
187
Figure 76-Photograph of abundant and distinct vertical trace fossils that characterize the
peloidal mudstone-wackestone subfacies of Lithofacies D, Sinbad
Limestone Member, Miners Mountain Locality. Rock hammer for scale.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
189
Figure 77-Photograph of the peloidal packstone in thin section from Interval 1 of the
skeletal calcarenite facies, Sinbad Limestone Member, Roadcut Locality.
Note the circumgranular equant sparry cement encircling the peloids. Field
of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
191
Figure 78-Photograph of the skeletal packstone in thin section from Interval 1 of the
skeletal calcarenite facies, Sinbad Limestone Member, Roadcut Locality.
Note the microgastropods and bivalves. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
193
cement are present, too. Very rare bivalves occur as voids with micritic envelopes (Figure
79). The intergranular matrix is micritic and dolomitic cement. Interval 6 is a skeletal
packstone containing very abundant whole and broken bivalves (Figure 80). The bivalve
fragments range from 0.25 - 3 mm in length and have been neomorphosed to
microcrystalline sparry calcite. Echinoderm material is rare. Non-skeletal allochems are
composed of rare peloids occurring as clots filled with sparry calcite and quartz grains
coated with hematite. The intergranular matrix is microcrystalline sparry cement and
secondary dolomite.
Three thin sections from the Jackass Benches Locality were examined. Interval 1
is a peloidal wackestone whose allochems consist of 0.2 -1 mm wide peloids encircled
with equant sparry cement (Figure 81). Some peloids occur as clots filled with sparry
calcite cement. Microcrystalline sparry calcite and dolomite cement fill the intergranular
porosity. Interval 6 is a skeletal packstone. Skeletal allochems include: 1) whole and
broken bivalves 0.2 - 5 mm long, neomorphosed to equant sparry calcite, and 2) whole
and broken microgastropods 1 mm long, neomorphosed to equant sparry calcite whose
voids are filled with micrite and equant sparry cement (Figures 82 and 83). Micrite,
microcrystalline spar, and dolomite cement fill the intergranular porosity and hematite
occurs as stains. Interval 13 is an oolitic wackestone consisting mostly of 0.25 mm wide
ooids encircled by equant sparry cement (Figure 84). Also occurring in this interval are:
1) rare, 2 mm long fragments of bivalves exhibiting moldic porosity or neomorphism to
microcrystalline cement that are encircled by equant sparry cement, and 2) rare
microgastropods neomorphosed to microcrystalline sparry cement that are filled with
ooids and microgranular sparry cement. The intergranular porosity contains
microcrystalline sparry calcite and primary porosity.
Two thin sections were examined from the Black Box Locality. Interval 1 is a
peloidal wackestone containing mostly 0.25 - 0.5 mm peloids encircled by equant sparry
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
194
Figure 79-Photograph of the peloidal wackstone in thin section from the skeletal
calcarenite facies, Sinbad Limestone Member, Batten and Stokes Locality.
Note the void in the shape o f a bivalve. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
196
Figure 80-Photograph o f a skeletal packstone in thin section from the skeletal calcarenite
facies, Sinbad Limestone Member, Batten and Stokes Locality. Note the
abundant mollusk fragments. Field of view is 7 mm. Magnification is 25
X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
197
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
198
Figure 81-Photograph of peloidal packstone in thin section from Interval 1 of the skeletal
calcarenite facies, Sinbad Limestone Member, Jackass Benches Locality.
Note the circumgranular equant sparry cement encircling the peloids. Field
o f view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
200
Figure 82-Photograph of a skeletal packstone in thin section from the skeletal calcarenite
facies, Sinbad Limestone Member, Jackass Benches Locality. Note the
abundant mollusk and echinoderm fragments. Field o f view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
201
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
202
Figure 83-Photograph o f a skeletal packstone in thin section from the skeletal calcarenite
facies, Sinbad Limestone Member, Jackass Benches Locality. Note the
abundant microgastropod and bivalve fragments. Field of view is 7 mm.
Magnification is 25X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
204
Figure 84-Photograph of the oolitic wackestone in thin section from the Sinbad Limestone
Member, Jackass Benches Locality. Note the ooids, microgastropods, and
possible scaphopod and benthic forams. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
206
cement (Figure 85). Rare skeletal fragments include bivalves exhibiting moldic porosity
and microgastropods filled with microcrystalline spar. Intergranular porosity consists of
microcrystalline sparry cement, primary porosity, and hematite staining. Interval 13 is a
skeletal wackestone whose skeletal allochems appear to consist solely o f 1 -3 mm long
whole and broken bivalves neomorphosed to equant sparry calcite (Figure 86). Hematite
staining is present and microcrystalline spar in small patches fills in as intergranular matrix.
Two thin sections from the Junction Locality were examined. Interval 4 is a
skeletal packstone consisting of: 1) 1 - 4 mm long, whole and broken bivalves
neomorphosed to equant sparry calcite, 2) 2 mm long, whole and broken
microgastropods neomorphosed to equant sparry calcite and filled with micrite and
microcrystalline spar, and 3) 0.5 mm echinoderm fragments (Figure 87). The
intergranular matrix is composed o f microcrystalline spar. Interval 8 is also a skeletal
packstone and it contains: 1) abundant 0.2 - 8 mm long, whole and broken bivalves
neomorphosed to equant sparry calcite, 2) 2 mm long, whole and broken
microgastropods neomorphosed to equant sparry calcite and filled with micrite and equant
sparry calcite (Figure 88), and 3) echinoderm fragments encircled by equant sparry calcite
cement (Figure 89). Microcrystalline calcite and micrite compose the intergranular matrix.
Tmsdak U pliJiJjimlitm
Five thin sections were examined from the Fish Creek Locality. Interval 1 was
determined to be a skeletal wackestone in thin section. Bivalves 1 mm long and
microgastropods 2.5 mm long have been badly recrystallized (Figures 90 and 91).
Microgastropod voids are filled with micrite and appear to be whole. Rare non-skeletal
allochems include peloids and ooids that have been badly recrystallized and encircled by
cement. The intergranular matrix consists of microcrystalline sparry calcite, dolomite
rhombs, and chalcedony. Interval 9 is a skeletal packstone containing: 1) abundant 1 -2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
207
Figure 85-Photograph of peloidal packstone in thin section from Interval 1 of the skeletal
calcarenite fecies, Sinbad Limestone Member, Black Box Locality. Note
the circumgranular equant sparry cement encircling the peloids. Field of
view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
209
Figure 86-Photograph of skeletal wackestone in thin section from the skeletal
calcarenite facies, Sinbad Limestone Member, Black Box Locality. Note
the thin bivalve fragments and fracture. Arrow points to bivalves. Field of
view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
211
Figure 87-Photograph of skeletal packstone in thin section from the skeletal calcarenite
facies, Sinbad Limestone Member, Junction Locality. Note the abundant
bivalve and microgastropod fragments. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
213
Figure 88-Photograph of skeletal packstone in thin section from the skeletal calcarenite
facies, Sinbad Limestone Member, Junction Locality. Note the abundant
bivalve fragments and the whole microgastropod. Field o f view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
214
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
215
Figure 89-Photograph of skeletal packstone in thin section from the skeletal calcarenite
facies, Sinbad Limestone Member, Junction Locality. Note the echinoderm
fragment. Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
216
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
217
Figure 90-Photograph of skeletal wackestone in thin section from Lithofacies A,
Sinbad Limestone Member, Fish Creek Locality. Note the abundant
bivalve fragments. Field of view is 7 mm. Magnification is 25 X with
crossed polars.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
218
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
219
Figure 91-Photograph of skeletal wackestone in thin section from Lithofacies A,
Sinbad Limestone Member, Fish Creek Locality. Note the abundant
bivalve fragments and what appears to be a microgastropod. Field of view
is 7 mm Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
221
mm long whole and broken bivalves neomorphosed to equant sparry calcite and 2) 1 mm
long whole and broken microgastropods neomorphosed to equant sparry calcite and filled
with micrite, quartz grains, dolomite rhombs, and microciystalline spar (Figures 92 and
93). Non-skeletal allochems include 0.25 to 1.5 mm wide peloids. Microcrystalline sparry
calcite composes the intergranular matrix, which also contains hematite staining and
dolomite rhombs. Interval 13 is a skeletal packstone containing: 1) 0.5 - 3 mm broken
bivalves that have been dolomitized or neomorphosed to sparry calcite and created shelter
porosity (Figure 94), 2) echinoderm fragments, and 3) 2 mm long fragments o f broken
microgastropods that have been dolomitized or neomorphosed to sparry calcite (Figure
95). Voids in the microgastropods are filled with dolomite rhombs and micrite. Interval
16 is a skeletal wackestone containing 1) abundant echinoderm fragments (Figure 96), 2)
broken bivalves neomorphosed to sparry calcite, and 3) 3 mm long whole and broken
microgastropods neomorphosed to sparry calcite, filled with micrite. Some of the
microgastropods have been nearly completely leached away (Figure 97). Peloids are rare
and micrite makes up the intergranular matrix. Interval 21 is also a skeletal packstone
including: 1) abundant bivalve fragments and a few whole specimens, all dolomitized and
2) rare whole and broken microgastropods neomorphosed to sparry cement and filled
with dolomite rhombs and skeletal material (Figure 98). Peloids occur 0.5 - 3 mm wide,
filled with dolomite rhombs and ooids occur as 0.1 mm wide ghosts. Microgranular spar
and dolomicrite constitute the intergranular matrix.
Four thin sections were examined from the Miners Mountain Locality. Interval 3
was determined to be a mudstone and, in thin section, contained absolutely no allochems,
skeletal or non-skeletal. Interval 9 is a peloidal packstone composed mainly of 0.25 -1.5
mm wide peloids and clots and fewer relict ooids, 0.1 mm wide, filled with dolomite. Rare
bivalves occur as either voids with micrite envelopes or neomorphosed to dolomicrite
(Figure 99). Microgastropods are very rare and broken. Micrite and microgranular spar
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
222
Figure 92-Photograph of skeletal packstone in thin section from Lithofacies B, Sinbad
Limestone Member, Fish Creek Locality. Note the abundant bivalves and
microgastropods. Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
224
Figure 93-Photograph of skeletal packstone in thin section from Lithofacies B, Sinbad
Limestone Member, Fish Creek Locality. Note the abundant bivalves,
microgastropods, and dolomite rhombs. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
225
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
226
Figure 94-Photograph of skeletal packstone in thin section from Lithofecies B, Sinbad
Limestone Member, Fish Creek Locality. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
228
Figure 95-Photograph of skeletal packstone in thin section from Lithofacies B, Sinbad
Limestone Member, Fish Creek Locality. Note the abundant bivalve fragments
and microgastropods. Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
230
Figure 96-Photograph of skeletal wackestone in thin section from Lithofacies D, Sinbad
Limestone Member, Fish Creek Locality. Note the echinoid spines. Field
of view is 7 mm. Magnification is 25 X with crossed polars.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
232
Figure 97-Photograph of skeletal wackestone in thin section from Lithofacies D, Sinbad
Limestone Member, Fish Creek Locality. Note the microgastropod that
has been almost completely dissolved away. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
234
Figure 98-Photograph of skeletal packstone in thin section from Lithofacies D, Sinbad
Limestone Member, Fish Creek Locality. Note the bivalve fragments,
microgastropods, and peloids. Field of view is 7 mm. Magnification is 25
X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
236
Figure 99-Photograph of peloidal packstone in thin section from Lithofacies A, Sinbad
Limestone Member, Miners Mountain Locality. Note the relict peloids and
ooids. Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
238
compose the intergranular matrix. Interval 17 is a skeletal packstone containing: 1) 1 -3
mm long broken bivalve fragments neomorphosed to spar and dolomite and 2) 1 mm long
broken and whole microgastropods neomorphosed to sparry calcite and filled with micrite
and dolomite rhombs (Figures 100 and 101). The intergranular matrix is dolomite cement.
Interval 21 is also a skeletal packstone. It contains: 1) 1 mm long, whole
microgastropods neomorphosed to sparry calcite and dolomite, filled with micrite, spar,
and dolomite (Figure 102), 2) whole bivalves neomorphosed to sparry calcite (Figure
103), and 3) echinoderm fragments (Figure 104). Micrite, sparry cement, and dolomite
compose the intergranular matrix.
Paleoenvironmental Analyses
Results from this study were combined with Blakey’s (1974) and Dean’s (1980) to
interpret the depositional environments in which all the Sinbad Limestone Member
lithofacies were formed.
San Rafael Swell
The diverse suite oflithologies and sedimentary structures found in the Sinbad in
the San Rafael Swell indicate that it was deposited in a variety of depositional
environments (Blakey, 1974).
The above-mentioned field and petrographic observations support Blakey’ s (1974)
earlier findings that the skeletal calcarenite facies contains the most diverse and abundant
fauna in the Sinbad Limestone Member. Because of this, the skeletal calcarenite was the
most intensively studied facies in this study in the San Rafael Swell. Sedimentary
structures noted in the skeletal calcarenite from this study and by Blakey (1974) include
large-scale cross-stratification, ooids, flat-pebble conglomerates, and herringbone
structures, indicative of environments of turbulent water. The horizontal laminations and
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
239
Figure 100-Photograph of skeletal packstone in thin section from Lithofacies B, Sinbad
Limestone Member, Miners Mountain Locality. Note the whole and
broken bivalves and the whole microgastropods. Field of view is 7 mm.
Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
240
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
241
Figure 101-Photograph of skeletal packstone in thin section from Lithofacies B, Sinbad
Limestone Member, Miners Mountain Locality. Note the broken bivalves
and microgastropods. Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
243
Figure 102-Photograph of skeletal packstone in thin section from Lithofacies D, Sinbad
Limestone Member, Miners Mountain Locality. Note the whole
microgastropod with two smaller microgastropods in its biggest chamber.
Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
245
Figure 103-Photograph of skeletal packstone in thin section from Lithofecies D, Sinbad
Limestone Member, Miners Mountain Locality. Note the bivalves and
microgastropods. Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.
247
Figure 104-Photograph of skeletal packstone in thin section from Lithofacies D, Sinbad
Limestone Member, Miners Mountain Locality. Note the echinoderm
fragment. Field of view is 7 mm. Magnification is 25 X.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
248
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
249
abundant trace fossils of the mudstones indicate deposition in relatively calm
environments. Therefore, the alternating skeletal packstones and skeletal wackestones
with mudstones in the skeletal calcarenite can be attributed to large storms followed by
relatively calmer periods. Blakey (1974) suggested two subenvironments of deposition for
the skeletal calcarenite based on the nature of the skeletal material he recognized. The
well-sorted ooids with skeletal fragments as nuclei found in many of the skeletal
packstones suggest deposition in turbulent water on offshore lime-sand bars (Blakey,
1974). The co-occurrence of whole microgastropods, bivalves, and scaphopods with
broken skeletal fragments indicates that the whole shells did not suffer the same turbulent
history as did the broken skeletal fragments and ooids. Recall that thin section analyses in
this study revealed that there is commonly micrite between the skeletal grains in the
skeletal packstones and skeletal wackestones and that voids within microgastropods are
commonly filled with micrite. Recall also that field observations revealed that most of the
skeletal grains in this lithofacies are closely packed. So, the whole shells were preserved
in troughs between bars or in quiet environments on the lee side ofbars where mud
accumulated in and around the shells (Blakey, 1974). The broken shells and ooids were
periodically washed in between the bars (Blakey, 1974).
The silty peloidal calcilutite facies is characterized by an abundance ofpeloids and
a low diversity fauna, consisting only of very few microgastropods and bivalves. These
characteristics can be indicative of shallow, low-energy, restricted marine conditions
(Tucker and Wright, 1990). This facies was probably deposited in a poorly circulated
carbonate lagoon between the shoreline and the offshore calcarenite bars. Blakey (1974)
believes that this lagoon was subject to varying energy conditions; the energy of waves
and greater turbulence occurred during storms or shifts in positions of the offshore
skeletal calcarenite bars while most of the time it was protected by them. The varying
degrees of turbulence could explain the occurrence o f non-resistant, micritic intervals as
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
250
well as more resistant intervals with skeletal material and intraclasts in the silty peloidal
calcilutite.
The abundance of pellets and the restricted fauna of the dolomitized calcarenite
probably indicate deposition in lagoons or is shallow-water restricted embayments in the
San Rafael Swell (Blakey, 1974). According to Blakey (1974), the dolomite in the Sinbad
is of early diagenetic or penecontemporaneous origin.
The skeletal calcarenite thickens to the west and north away from the thin eastern
edge of the Sinbad, suggesting offshore deposition (Blakey, 1974). The silty peloidal
calcilutite is found between the skeletal calcarenite and the dolomitized calcarenite,
indicating an intermediate position of deposition farther offshore than the dolomitized
calcarenite but closer to shore than the skeletal calcarenite. The dolomitized calcarenite
makes up most or all of the thin Sinbad at its southern and eastern margins, while to the
west it forms the top of the Member, topping the silty peloidal calcilutite and skeletal
calcarenite. These patterns suggest that deposition prograded westwardly over offshore
facies (Blakey, 1974).
Teasdale Uplift
The dolomicrite subfacies and the oolite-peloid packstone subfacies of Lithofacies
A seen at the Fish Creek and Miners Mountain were deposited in supratidal and intertidal
environments that marked the first phase of the advance of the Sinbad Sea (Dean, 1981).
The dolomicrite subfacies has been interpreted by Dean (1981) to have been deposited in
tidal ponds between tidal channels in the intertidal zone or in supratidal flats (Figure 105).
The accumulations of microgastropods at the top of this interval at the Fish Creek locality
probably represent storm lags. The peloids and ooids of the oolite-peloid packstone
subfacies probably originated in subtidal lagoons and then were transported onto the tidal
flat or accumulated as bars in tidal channels during normal tides and storms (Dean, 1981).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
251
Since pelletal muds with varying amounts of skeletal material characterize modem
carbonate lagoons (Sellwood, 1973), the skeletal packstone and pelletal wackestone
subfacies of Lithofacies B are interpreted to represent deposition in lagoons (Dean, 1981).
The decrease in faunal diversity (compared with Lithofacies D) may represent salinity
increases common in restricted lagoons (Dean, 1981). Dean (1981) relates the influx of
skeletal material and the bioturbation in the following way: tides or storms bring skeletal
debris into the lagoon that are overlain by pelletal sediments that become thicker and more
and more bioturbated until the surge of another storm. Deposition o f Lithofacies B marks
the second phase of Sinbad deposition and the advance of the subtidal zone over the
shoreline (Dean, 1981) (Figure 105).
Lithofacies C represents a temporary regression of the Sinbad Sea because these
unfossiliferous, tidal-flat rocks are sandwiched between rocks that are subtidal in origin
(Dean, 1981). The extensive bioturbation found in these rocks is characteristic of channel
sediments in modem intertidal zones (Shinn et at, 1969).
Lithofacies D documents the return of marine conditions (Dean, 1981). Evidence
suggests that deposition o f this facies took place under less restricted, more nearly open
marine conditions than Lithofacies B. For example, ooids, echinoderms and ammonoids
are abundant in the oolite-mollusk packstone subfacies, all indicating deposition on the
seaward, rather than the restricted lagoonal side of ooid shoals. The peloidal
mudstone-wackestone subfacies represents the maximum transgression of the Sinbad sea
(Dean, 1981).
Because Lithofacies E is characterized by oolite granistones, this facies in the
Teasdale Uplift was probably deposited on shoals and bars that formed at the high-energy
interface between the lagoon and the open marine shelf (Dean, 1981). These grainstones
were deposited in the final regressive phase o f the Sinbad Limestone.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Figure 105- Diagram showing the relationships of depositional environments along the
Sinbad Sea shoreline (modified from Dean, 1981).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
253
SupfotkSol - Sobko Zone
Intertidal Zone
Logoonal Subtidal
Oolite - Peitotd Shools
Open Marine Subtidal
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
open marine subtidal
254
Dean’s (1981) lithofacies B and D of the Sinbad Limestone Member in the
Teasdale Uplift are most similar to Blakey’s (1974) basal skeletal calcarenite of the Sinbad
in the San Rafael Swell. Lithofacies C recognized in the Teasdale Uplift went unnoticed
by Blakey (1974) in the San Rafael Swell. Blakey’s (1974) silty calcilutite probably
represents a lateral facies change of Dean’s (1981) lithofacies E. Dolomite in the upper
portion of lithofacies E in the Teasdale Uplift (Dean, 1981) almost certainly correlates
with the dolomitized skeletal calcarenite in the San Rafael Swell (Blakey, 1974).
Faunal Abundance Data
In Appendix B, all raw fauna! abundance data for the seven Sinbad Limestone
Member localities in southern Utah is given. In Appendix C, all raw data for the
preservation and abundance of only microgastropods and bivalves for the seven Sinbad
Limestone Member localities is given.
Figures 106 and 107 reveal the percentage abundances of fossils found for each of
the twenty disaggregated intervals from the seven Sinbad Limestone Member localities.
Microgastropods and bivalves compose 37% to 100 % of the total fauna from all
localities. Bivalves are present in all twenty intervals, sometimes composing up to nearly
100% of the fauna, such as in Interval 13 of the Jackass Benches Locality, Interval 13 of
the Black Box Locality, Interval 8 of the Junction Locality, all five Intervals of the Fish
Creek Locality, and Interval 21 of the Miners Mountain Locality. Microgastropods are
present in all but one interval and they also have a dominant presence in many intervals,
composing over 50 % of the fauna in Interval 1 of the Roadcut Locality, Interval 1 o f the
Batten and Stokes Locality, Interval 1 of the Jackass Benches Locality, Interval 1 of the
Black Box Locality, and Intervals 1 and 17 of the Miners Mountain Locality. Only in
Interval 8 from the Roadcut Locality are neither bivalves nor microgastropods the
dominant taxa.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
255
Figure 106: Faunal abundance data for disaggregated intervals sampled from the Roadcut,
Batten and Stokes, Jackass Benches, and Black Box Localities o f the
Sinbad Limestone Member. See Appendix A for raw data. The percentage
abundance of each fossil organism has been plotted for each of the twenty
intervals that were disaggregated in the laboratory. Interval 6 of the Black
Box Locality is not included because the fossil material was too numerous
to count.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Roadcut Locality,
Sinbad Limestone Member
skeletal
calcarenite
facies
Jack ass B enches Locality, Sinbad
Limestone Member
60% -
40%
© 20%
Q.
dolomitized
calcarenite calcarenite
■ L i n g u l a
B s c a p h o p o d s
H b i v a l v e s
B m i c r o g a s t r o p o d s
facies
Batten and Stokes Locality,
Sinbad Limestone Member
B b iv a v le s
1 0 m i c r o g a s t r o p o d s
skeletal
calcarenite
facies
Black Box Locality,
Sinbad Limestone Member
100%
20% -
skeletal
calcarenite
facies
■ U n g u i a
B s c a p h o p o d s
B b iv a v le s
B m ic r o g a s t r o p o d s
ro
Ur
o\
257
Figure 107: Faunal abundance data for disaggregated intervals sampled from the Junction,
Fish Creek and Miners Mountain Localities, Sinbad Limestone Member.
See Appendix A for raw data. The percentage abundance of each fossil
organism has been plotted for each of the twenty intervals that were
disaggregated in the laboratory.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Junction Locality, Sinbad
Limestone Member
Fish Creek Locality,
Sinbad Limestone Member
100%
80%
60%
40%
20% +
0%
skeletal
cacarenne
B s c a p h o p o d s
B b i v a l v e s
0 m i c r o g a s t r o p o d s
to
0
»
H
c
©
£
100%
80%
60%
40%
20%
0%
■ e c h i n o d e r m s
■ L i n g u l a
B s c a p h o p o d s
H b i v a l v e s
B m i c r o g a s t r o p o d s
facies
8
facies
Miners Mountain Locality, Sinbad
Limestone Member
cn
0
H
&
facies
B b iv a lv e s
B m i c r o g a s t r o p o d s
258
259
Figures 108 and 109 reveal the percentage abundances of fossils found in each
facies of the seven Sinbad Limestone Member localities. Like the data in Figures 106 and
107, this chart shows that bivalves and microgastropods are the dominant taxa in all facies
except the Roadcut Locality of the San Rafael Swell.
In Figure 110, the data from the twenty disaggregated intervals from the seven
Sinbad localities was combined to show the percentage abundance of each fossil organism
for each facies in the two geographic regions of this study. By looking at these graphs, it
is clear that bivalves and microgastropods are the dominant fauna in both the San Rafael
Swell and the Teasdale Uplift. Combining the faunal abundance data from the
disaggregated intervals indicates that microgastropods make up 42% of the fauna in the
skeletal calcarenite and 24% of the dolomitized calcarenite of the San Rafael Swell.
Bivalves make up 39% o f the fauna associated with the skeletal calcarenite and 76% of the
dolomitized calcarenite fauna. In the Teasdale Uplift, microgastropods make up 29%,
41%, and 2% of the faunas from Lithofacies A, B, and D, respectively. Bivalves dominate
with abundances of 71%, 58%, and 97% of the faunas of Lithofacies A, B, and D,
respectively.
Figures 106 -110 reveal that every Sinbad paleocommunity and every Sinbad
depositional environment is dominated by only two groups of taxa: bivalves and
microgastropods. Bivalves are a strong background signal in the Sinbad; they are found
in great abundances in every disaggregated interval and in every depositional facies o f the
Sinbad Limestone Member. Microgastropods are a strong second only to bivalves
because they numerically dominate the faunas of many of the disaggregated intervals and
are found throughout every depositional environment recorded in the Sinbad.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
260
Figure 108-Faunal abundance data for facies sampled from the Roadcut, Batten and
Stokes, Jackass Benches, and Black Box Localities, Sinbad Limestone
Member. See Appendix A for raw data. The data from the twenty
intervals from the seven Sinbad localities that were disaggregated and
analyzed was combined for each locality to show the percentage abundance
of each fossil organism plotted against each facies. Interval 6 of the Black
Box Locality is not included because the fossil material was too numerous
to count.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Roadcut Locality,
Sinbad Limestone Member
«
t
c
»
&
&
100% 1
80%
60%
40%
20%
0%
S L - R C 1 S L - R C 8
interval
■ L i n g u l a
0 s c a p h o p o d s
S b i v a v l e s
1 1 m ic r o g a s t r o p o d s
Batten and Stokes Locality, Sinbad
Limestone Member
&
i
S I b i v a v l e s
■ m i c r o g a s t r o p o d s
interval
Jack ass B enches Locality,
Sinbad Limestone Member
O )
«
&
o >
100%
80%
60%
40%
20%
0%
in
S L - J B 1 S L - J B 6
interval
S L - J B 1 3
■ L i n g u l a
■ s c a p h o p o d s
§ 9 b i v a v l e s
■ m ic r o g a s t r o p o d s
Black Box Locality,
Sinbad Limestone Member
100%
4 0 % -
20%
S L - B B S L - B B 1
interval
■ L i n g u l a
■ s c a p h o p o d s
■ b i v a l v e s
B m ic r o g a s t r o p o d s
262
Figure 109-Faunal abundance data for facies sampled from the Junction, Fish Creek and
Miners Mountain Localities. See Appendix A for raw data. The data from
the twenty intervals from the seven Sinbad localities that were
disaggregated and analyzed was combined for each locality to show the
percentage abundance of each fossil organism plotted against each facies.
Interval 6 of the Black Box Locality is not included because the fossil
material was too numerous to count.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Junction Locality,
Sinbad Limestone Member
100%
a 20%
3 s c a p h o p o d s
3 b i v a l v e s
3 m ic r o g a s t r o p o d s
S L - J 4 S L - J 8
interval
Fish Creek Locality,
Sinbad Limestone Member
100%
8 0 %
6 0 %
4 0 %
20%
0%
B e c h ln o d e r m s
■ L i n g u l a
B s c a p h o p o d s
B b i v a l v e s
B m i c r o g a s t r o p o d s
S L -
F C
1
S L -
F C
9
S L -
F C
1 3
interval
S L -
F C
S L -
F C
21
Miners Mountain Locality, Sinbad
Limestone Member
©
a >
100%
8 0 %
S 6 0 %
g 4 0 %
© 20%
a
o %
■ s H s H s I l!
B b i v a l v e s
B m i c r o g a s t r o p o d s
S L -
M M
3
S L -
MM
S L -
1 7
S L -
M M
21
interval
to
ON
O J
264
Figure 110-Faunal abundance data for facies from the San Rafael Swell and the Teasdale
Uplift, Sinbad Limestone Member. The data from the twenty
disaggregated and analyzed intervals from the seven Sinbad localities was
combined here to show the percentage abundance of each fossil organism
plotted for each facies in the two geographic regions of this study. Interval
6 of the Black Box Locality is not included because the fossil material was
too numerous to count.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
San Rafael Swell,
Sinbad Limestone Member
s k e le t a l d o l o m i t i z e d
c a l c a r e n it e c a l c a r e n it e
facies
■ L i n g u l a
B s c a p h o p o d s
B b i v a l v e s
B m ic r o g a s t r o p o d s
Teasdale Uplift,
Sinbad Lim estone Member
A B D
facies
■ e c h i n o d e r m s
B s c a p h o p o d s
1 ! b i v a v l e s
B m i c r o g a s t r o p o d s
to
ON
266
Ranking Results
Figure 111 is a chart showing the number of intervals counted per ranking for each
facies of the Sinbad Limestone Member of the San Rafael Swell. These results combine
field observations and laboratory data. Intervals that did not contain abundant fossils were
not ranked, such as many of the intervals within the silty peloidal calcilutite facies and the
dolomitized facies. Bivalve-dominated assemblages are the most common type of
assemblage for all facies in the San Rafael Swell. Of 38 ranked intervals of the skeletal
calcarenite facies, 26 of them are ranked as 2, or bivalve-dominated. Six intervals are
ranked as 1, microgastropod-dominated and six intervals are ranked as 3, having a mixed
microgastropod/bivalve assemblage. In the silty peloidal calcilutite facies, 4 of 5 ranked
intervals are bivalve-dominated and 1 interval is microgastropod-dominated. The only
interval containing enough fossils to be ranked in the dolomitized calcarenite facies is
bivalve-dominated.
Figures 112 and 113 show the number of intervals counted per ranking for each
facies of the Sinbad Limestone Member of the Teasdale Uplift. These results combine
field observations and laboratory data. Intervals that did not contain abundant fossils were
not ranked. Like the San Rafael Swell, most of the ranked assemblages in the Teasdale
Uplift are bivalve-dominated assemblages. However, in Lithofacies A, 4 o f 7 ranked
intervals are microgastropod-dominated assemblages and the remaining 3 intervals are
bivalve-dominated intervals. In Lithofacies B, 8 of 12 ranked intervals are
bivalve-dominated assemblages and 3 of the 12 ranked intervals are
microgastropod-dominated. All of the intervals ranked in Lithofacies C, D, and E are
bivalve-dominated assemblages. Only 2 of the intervals ranked in the Teasdale Uplift have
a mixed microgastropod/bivalve assemblage.
The results of scoring and ranking bulk samples reiterate the results from the
faunal abundance data. Bivalves and microgastropods dominate Sinbad
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
267
Figure 111-Interval rankings for the skeletal calcarenite, silty peloidal calcilutite, and
dolomitized calcarenite facies of the Sinbad Limestone Member, San Rafael
Swell, southern Utah. The number of intervals for each ranking has been
plotted. The rankings are: 1) microgastropod dominated (composing 60%
or more of the fossil assemblage), 2) bivalve dominated (composing 60%
or more of the fossil assemblage, or 3) mixed microgastropod/bivalve
assemblage (containing 40% to 60% of microgastropods and 40% to 60%
o f bivalves).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Skeletal Calcarenite Facies,
San Rafael Swell, Sinbad Limestone Member
16
1 (gastropod-dominated) 2 (bivalve-dominated) 3 (mixed assemblage)
ranking
Silty Pelloidal Calcilutite Facies,
San Rafael Swell, Sinbad Limestone Member
1 (gastropod-dominated) 2 (bivalve-dominated) 3 (mixed assemblage)
ranking
Dolomitized Calcarenite Facies,
San Rafael Swell, Sinbad Limestone Member
1 (gastropod-dominated) 2 (bivalve-dominated)
ranking
3 (mixed assemblage)
268
269
Figure 112-Interval rankings for Lithofacies A, B, and C of the Sinbad Limestone
Member, Teasdale Uplift, southern Utah. The number of intervals for each
ranking has been plotted. The rankings are: 1) microgastropod dominated
(composing 60% or more of the fossil assemblage), 2) bivalve dominated
(composing 60% or more of the fossil assemblage, or 3) mixed
microgastropod/bivalve assemblage (containing 40% to 60% of
microgastropods and 40% to 60% of bivalves).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Lithofacies A,
Teasdale Uplift, Sinbad Limestone Member
1 (gastropod- 2 (bivalve-dominated) 3 (mixed assemblage)
dominated)
ranking
Lithofacies B,
Teasdale Uplift, Sinbad Limestone Member
1 (gastropod- 2 (bivalve-dominated) 3 (mixed
dominated) assemblage)
ranking
Lithofacies C,
Teasdale Uplift, Sinbad Limestone Member
10
9
8
7 +
6
5
4
3
2
1 (gastropod-
dominated)
2 (bivalve-dominated)
ranking
3 (mixed assemblage)
270
271
Figure 113-Interval rankings for Lithofacies D and E of the Sinbad Limestone
Member, Teasdale Uplift, southern Utah. The number of intervals for each
ranking has been plotted. The rankings are: 1) microgastropod dominated
(composing 60% or more of the fossil assemblage), 2) bivalve dominated
(composing 60% or more of the fossil assemblage, or 3) mixed
microgastropod/bivalve assemblage (containing 40% to 60% of
microgastropods and 40% to 60% o f bivalves).
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Lithofacies D,
Teasdale Uplift, Sinbad Limestone Member
1 (gastropod- 2 (bivalve-dominated) 3 (mixed
dominated) gastropods/bivalves)
ranking
Lithofacies E,
Teasdale Uplift, Sinbad Limestone Member
1 (gastropod- 2 (bivalve-dominated) 3 (mixed
dominated) gastropods/bivalves)
ranking
t o
-j
to
273
paleocommunkies. Bivalve-dominated intervals prevail over most of the Sinbad, but
microgastropod-dominated intervals are competing for attention.
Size Analysis
Figure 114 shows the data collected from the height measurements of
microgastropods from the skeletal calcarenite and dolomitized calcarenite facies of the
Sinbad in the San Rafael Swell. Intervals and facies not included in the counts either
contained no microgastropods or the microgastropods were too difficult to measure.
According to the histograms, all but one microgastropod measured from the skeletal
calcarenite was measured to be under one centimeter in height. Of the 290
microgastropods that were measured, 74 were between 0 and 0.9 mm in height and 106
were between 1 and 1.9 mm in height. Sixty-two percent of the microgastropods
measured from the skeletal calcarenite facies were under 2 mm in height. The dolomitized
calcarenite contained significantly fewer microgastropods, but all of the microgastropods
measured for this facies were under 4.9 mm in height.
Figure 115 shows the data collected from the height measurements of
microgastropods from Lithofacies A and B of the Sinbad in the Teasdale Uplift. Intervals
and facies not included in the counts either contained no microgastropods or the
microgastropods were too difficult to measure. Only 19 microgastropods were measured
from Lithofacies A. All but 2 microgastropods measured were under 1 cm in height.
Seventy-nine percent of the microgastropods measured were under 5 mm in height.
Lithofacies B contained more microgastropods than Lithofacies A, but they do not exhibit
the same range in height as the microgastropods from Lithofacies A. Of the 56
microgastropods that were measured, 40 are less than 1 mm in height. All of the
microgastropods measured from Lithofacies B are less than 4 mm in height.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
274
Figure 114-Histograms showing size in millimeters versus the number of microgastropods
for the skeletal calcarenite and the dolomitized calcarenite facies of the
Sinbad Limestone Member, San Rafael Swell.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Skeletal Calcarenite Facies,
Sinbad Limestone Member, San Rafael Swell
B 40
I
2-2.9 3-3.9 4-4.9 5-5.9 6-6.9 7-7.9 8-0.9 9-9.9 10-10.9
size in millimeters
10 •
9 -
8
7 -
6 -
5
4 -
3
2
1 -
0 -
Dolomitized Calcarenite Facies,
Sinbad Limestone Member, San Rafael Swell
I
0-0.9 1-1.9 2-2.9
size in millimeters
3-3.9 4-4.9
275
276
Figure 115-Histograms showing size in millimeters versus the number o f mierogastropods
for the Lithofacies A and B of the Sinbad Limestone Member, Teasdale
Uplift.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Lithofacies A,
Sinbad Lim estone M em ber, Teasdale Uplift
1 0 — ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
size in millimeters
Lithofacies B,
Sinbad Lim estone M em ber, S an R afael S w ell
0 -0.9 1-1.9 2 -2 .9 3-3.9
size in millimeters
277
278
Figure 116 shows the data collected from the height measurements of
microgastropods from all facies of the Sinbad at the San Rafael Swell and Teasdale Uplift
localities. The total number of microgastropods measured from all facies and localities in
this study is 376. Sixty-six percent of the total number of microgastropods measured were
under 2 mm in height. Of all the microgastropods measured, only 3 were taller than 1 cm
in height.
Post-extinction Early Triassic fauna are typified by very small size, or, the
“Lilliput Effect” (Twitchett, 1998). The data about microgastropod size obtained from
this research should provide additional understanding o f the “Lilliput Effect” phenomenon.
Ichnology
A very low-diversity trace fossil assemblage was documented from all measured
sections of the Sinbad Limestone Member; only Planolites, Rhizocorallium,
Diplocraterion, m d Arenicolites were found (Fraiser and Bottjer, 2001). Arenicolites is
the most abundant and widespread of the trace fossils found in the Sinbad and occurs in
nearly every lithology and every depositional environment.
DISCUSSION
Other Lower Triassic Localities
Western USA Localities
The Sinbad Limestone Member of the Moenkopi Formation recorded the second
Early Triassic transgression in western North America. In this section of this report, the
fauna of the Nammalian Sinbad Limestone Member is compared to the faunas present in
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
279
Figure 116-Histogram showing size in millimeters versus the number o f microgastropods
for the all facies of the Sinbad Limestone Member, San Rafael Swell and
Teasdale Uplift.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Sinbad Limestone Member,
Ail Facies of the San Rafael Swell and T easdale Uplift
size in millimeters
281
Griesbachian (Dinwoody Formation) and Spathian (Thanynes Formation and Virgin
Limestone Member) strata of western North America.
The Griesbachian Dinwoody Formation in southwestern Montana, eastern Idaho,
western Wyoming and northern Utah records the earliest Triassic marine transgression in
western North America (Pauli and Pauli, 1994). Rodland (1999) found a variety of taxa in
the fossil assemblage of the Dinwoody Formation, including: the inarticulate brachiopod
Lingula, the bivalves Claraia, Unionites, and Eumorphotis, the articulate brachiopod
Crurithyris, and unidentified gastropods, echinoids, and fish. Lingula was identified in all
lithologies and is the most abundant taxon in the Dinwoody, making up nearly 50% of the
fossil assemblages, followed closely by the bivalve genera Claraia, Eumorphotis,
Unionites. Microgastropods, echinoid spines, and fish scales are relatively rare compared
to the bivalves and inarticulate brachiopods. Ecological dominance by Lingula in a broad
variety of Dinwoody Formation oxygenated marine shelf environments supported
Rodland’s (1999) hypothesis that Lingula acted as an opportunist during the biotic
recovery from the end-Pemhan mass extinction
The third transgression is recorded in Spathian strata of western North America
and consists of the upper Thaynes Formation and the Virgin Limestone Member of the
Moenkopi Formation. The Early Triassic Thaynes Formation of western and north-central
Utah, Idaho, Montana, and Wyoming is divided into a scheme of four facies belts,
consisting of a basinal facies, an outer shelf facies, an inner shelf facies, and a red bed
facies (Carr, 1981; Carr and Pauli, 1983). The Virgin Member contains limestone units
deposited under normal marine conditions, intercalated with fine-grained siliciclastics and
sandstones, representing marginal and subtidal environments (Rief and Slatt, 1979).
Schubert and Bottjer (1995) conducted a paleoecologic study of the invertebrate faunas
from this seaways to determine what kind o f invertebrate communities persisted on the sea
floor at different times during the Early Triassic in the western USA. A more diverse
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
282
assemblage of higher taxa was found from the Spathian, when compared to the
Griesbachian Dinwoody Formation and the Mammalian Sinbad Limestone Member
(Schubert and Bottjer, 1995). The Spathian paleocommunities were dominated by
bivalves and brachiopods and are characterized by the first appearance of representatives
of important Mesozoic clades, Holocrinus smithi and Miocidaris utahensis. Gastropods
are neither abundant nor diverse in faunas of the Thaynes and Virgin.
Global Localities with faunas similar to the Sinbad Limestone Member
In Japan, the Triassic Kamura Formation was deposited as shallow-marine
carbonates built-up on a seamount in Panthalassa (Sano and Nakashima, 1997). The
Kamura is comprised of various carbonate types and is lithologically divided into the basal
(Griesbachian), lower (Dienerian, Smithian, Spathian), middle (Upper Ladinian), and
upper (Upper Camian, Norian) rock units (Sano and Nakashima, 1997). The basal
(Griesbachian) rock unit consists largely of microgastropod-dominated grainstones (Sano
and Nakashima, 1997). The lower (Dienerian, Smithian, Spathian) rock unit is composed
of bivalve and microgastropod packstones (Sano and Nakashima, 1997).
Within the Lower Triassic clayey sediments o f the Servino Formation in Italy are
red oolite and gastropod grainstones deposited on shoals in an ancient shallow
epicontinental sea, known as "oolite a gasteropodi" (Assereto and Rizzini, 1975). The
Siusi Member (Griesbachian and Dienerian) of the Werfen Formation, also in Italy,
possesses numerous microgastropod grainstones (Wignall and Twitchett, 1996).
Sinbad Limestone Member - this study
Schubert and Bottjer (1995) determined that the Mammalian Sinbad Limestone
paleocommunities exhibit a greater diversity at higher and lower taxonomic levels than the
Griesbachian Dinwoody Formation. A larger variety of bivalves and several species of
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
283
microgastropod absent in the Dinwoody are typically present in the Sinbad. Sinbad
Limestone paleocommunities can be very high in dominance, with one or two species of
microgastropod or bivalve being extremely numerous. The results obtained from this
detailed look at the paleoenvironments and paleoecology of the Sinbad are in accordance
with Schubert and Bottjer’s (1995) results. The Sinbad Limestone is characterized by
extraordinarily abundant bivalves and microgastropods, fewer scaphopods, and rare
Lingula and echinoderm debris. Though seemingly uninteresting, the dominance of
Sinbad Limestone paleocommunities by bivalves and microgastropods actually imparts
intriguing information about the ecological structure during the aftermath o f the greatest
extinction in the history of life.
It has previously been determined that bivalves are persistent, abundant, and
typical members of Lower Triassic strata in the western USA, including the Griesbachian
Dinwoody Formation and the Spathian Thaynes Formation and Virgin Limestone Member
of the Moenkopi Formation (e.g., Schubert and Bottjer, 1995). The bivalve genus
Claraia, and possibly all other bivalve genera found worldwide during the Early Triassic,
has potential as disaster taxa because of their great abundance and extensive geographic
range in the Early Triassic (Yin, 1985).
Results from this research reveal convincing indications that microgastropods, as
an ecological entity, behaved as biotic recovery opportunists during the aftermath o f the
end-Permian mass extinction. The combination o f being ecological dominants in a variety
of nearshore carbonate environments in the Lower Triassic Sinbad Limestone Member
with their occurrence throughout Lower Triassic strata around the world (e.g., Hallam and
Wignall, 1997) make microgastropods perfectly fit the definition of a biotic recovery
opportunist. It appears as though several taxa did exist as opportunists during the biotic
recovery from the end-Permian mass extinction.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
284
CONCLUSIONS
1) The fossil fauna of the Sinbad Limestone Member in southern Utah is
characterized by an impoverished diversity. Fossils include: a large abundance of
microgastropods and bivalves and smaller occurrences of scaphopods, ammonoids,
echinoderm fragments, and the inarticulate brachiopod Lingula.
2) The Sinbad Limestone Member in southern Utah was deposited in a variety of
environments along the coast of the Earty Triassic Sinbad Sea. These environments
include: subtidal, open marine conditions, offshore bars, restricted lagoons, and supratidal
flats.
3) The skeletal calcarenite facies of the Sinbad Limestone Member in the San
Rafael Swell and Lithofacies A, B and D of the Sinbad in the Teasdale Uplift contain
a greater abundance and diversity of fossils than any other facies. Most o f the
intervals ranked in the field and disaggregated in the laboratory come from the skeletal
calcarenite, Lithofacies A, Lithofacies B, or Lithofacies D.
4) In thin sections of the skeletal calcarenite from the San Rafael Swell, it was revealed
that 1) whole microgastropods, bivalves, and scaphopods co-occur with broken skeletal
fragments in the skeletal calcarenite of the Sinbad Limestone, 2) there is commonly
micrite between the skeletal grains in the skeletal packstones and skeletal wackestones of
this facies, and that voids within microgastropods are often filled with micrite, and 3)
most o f the skeletal grains in this lithofacies are closely packed. It is interpreted that the
whole shells were preserved in troughs between bars or in quiet environments on the lee
side of bars where mud accumulated in and around the shells the broken shells and ooids
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
285
were periodically washed in between the bars. So, the abundance and distribution of
microgastropods and other fossils in the skeletal calcarenite of the Sinbad Limestone
in the San Rafael Swell is a primary signal
5) The accumulations of microgastropods at the top of Interval 1 in Lithofacies A at
the Fish Creek locality probably represent stonn lags that are not a primary signal
of microgastropod abundance and environmental distribution.
6) The skeletal material in Lithofacies B was determined to be of limited diversity and,
therefore, deposited in a restricted lagoon. The fossil abundances and presences in
Lithofacies B are probably a primary signal
7) Whole and broken microgastropods were found in Lithofacies D, along with whole and
broken bivalves and echinoderm material. Voids within the microgastropods were filled
with the same material as the surrounding matrix. Because much of the skeletal
material was non-abraded and filled with the same micrite as the intergranular
m atrix, the abundances and occurrences of the fossils found in Lithofacies D are
thought to be a primary signal
8) Bivalves and microgastropods are the dominant taxa in all depositional
environments of the Sinbad Limestone Member in southern Utah. Bivalves are
found in great abundances in every disaggregated interval and in every depositional facies
of the San Rafael Swell and the Teasdale Uplift. Microgastropods also numerically
dominate the faunas of many of the disaggregated intervals and are found throughout
every depositional environment recorded in the Sinbad.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
286
9) Bivalve-dominated assemblages are the most common type of assemblage for all
facies in the San Rafael Swell Most of the ranked assemblages in the Teasdale
Uplift are bivalve-dominated assemblages. However, microgastropods make up a
significant portion of Sinbad Limestone Member fossils assemblages in all facies
found at all localities.
10) Ninety-nine percent of the total number of microgastropods measured in this
study were determined to be 1 cm or less in height.
11) Because microgastropods dominate a variety of depositional environments
numerically in the Sinbad Limestone Member in southern Utah and these
abundances and occurrences reflect a primaiy signal, microgastropods appear to
have behaved as biotic recoveiy opportunists during the biotic recovery from the
end-Permian mass extinction.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
REFERENCES
287
Assereto, R. L., and Rizzini, A., 1975, Reworked Ferroan Dolomite Grains in the Triassic
'oolite a gasteropodi" of Camoniche Alps (Italy) as indicators of early diagenesis.
Neues Jahrbuch for Geologie und Palaontologie Abhandlungen, v. 148 (2), p.
215-232.
Batten, R. L., 1973, The vicissitudes of the gastropods during the interval of
Guadalupian-Ladinian time. In: Logan, A., and Hills, L. V., (eds.), The Permian
and Triassic Systems and Their Mutual Boundary, Canadian Society of Petroleum
Geologists Memoir 2, p. 596-607.
Batten, R. L., and Stokes, W.L., 1986, Early Triassic gastropods from the Sinbad Member
of the Moenkopi Formation, San Rafael Swell, Utah. American Museum
Novitates, v. 2864, p. 1-33.
Blakey, R. C., 1974, Stratigraphic and depositional analysis of the Moenkopi
Formation, southeastern Utah. Utah Geological and Mineral Survey Bulletin, v.
104.
Benson, R. H., 1984, The Phanerozoic ‘crisis’ as viewed from the Miocene. In: W. A.
and van Couvering, J. A.,( eds.), The Proterozoic Biosphere, p. 437-446.
Beurlen, K., 1956, Der Faunenschnitt an der Perm-Trias Grenze. Zeitschrift der
Deutschen Geologischen Gesellschaft, v. 108, p. 88-99.
Bottjer, D.J., 2001, Biotic recovery from mass extinctions. In: Briggs, D.E.G. and
Crowther, P.R., (eds.), Paleobiology II, Blackwell Scientific Publications, Boston.
Boucot, A. J., 1983, Does evolution take place in an ecological vacuum? II. Journal of
Paleontology, v. 57, p. 1-30.
Boucot, A. J. and Gray, J., 1978, Comment on: ‘Catastrophe theory: application to the
Permian mass extinction’. Geology, v. 6., 646-647.
Bo wring, S. A., Erwin, D. H., Jin, Y. G., Martin, M. W., Davidek, K., and Wang, W.,
1998, U/Pb zircon geochronology and tempo of the end-Permian mass extinction.
Science, v. 280, p. 1039-1045.
Campbell, N. A., 1996, Biology, The Benjamin/Cummings Publishing Company, Inc.,
1206 p.
Campbell, I. H., Czamanske, G. K., Fedorenko, V. A., Hill, R. I., and Stepanov, V., 1992,
Synchronism of the Siberian Traps and the Permian-Triassic boundary. Science, v.
258, p. 1760-1763.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
288
Carr, T. R , 1981, Paleogeography, depositional history and conodont paleoecology of the
lower Triassic Thaynes Formation in the Cordilleran miogeocyncline. [Master’s
Thesis]: University of Wisconsin, Madison.
Carr, T. R. and Pauli, R. K., 1983, Early Triassic stratigraphy and paleogeography of the
Cordillera miogeocline. In: Dolly, E. D., Reynolds, M. W., and Spearing, D. R.
(eds.), Mesozoic Paleogeography of the West-central United States, Rocky
Mountain Paleogeography Symposium, 2, SEPM Rocky Mountain Section.
Chronic, H., 1988, Of Earth and Time, p. 1-28, In: Pages of Stone, The Mountaineers,
Seattle, WA, 158 p.
Dagys, A. S., 1993, Geographic differentiation ofTriassic brachiopods.
Palaeogeography, Palaeoclimatology, Palaeoecology, v. 100, p.79-87.
Dean, J. S., 1981, Carbonate petrology and depositional environments of the Sinbad
Limestone Member of the Moenkopi Formation in the Teasdale Dome area,
Wayne and Garfield Counties, Utah. Brigham Young University Geology Series,
v. 28, p. 19-51.
Droser, M. L., Bottjer, D. J., and Sheehan, P. M., 1997, Evaluating the ecological
architecture of major events in the Phanerozoic history of marine invertebrate life.
Geology, v. 25 (2), p. 167 - 170.
Erwin, D. H., 1989, Regional paleoecology o f Permian gastropod genera, southwestern
United States and the end-Permian mass extinction. Palaios, v. 4, p. 424-438.
Erwin, D. H., 1990, Carboniferous-Triassic gastropod diversity patterns and the
Permo-Triassic mass extinction. Paleobiology, v. 16 (2), p. 187-203.
Erwin, D. H., 1993, The great Paleozoic crisis, Columbia University Press, New York,
327 p.
Fagerstrom, J. A., 1987, The evolution of reef communities, John Wiley and Sons, New
York.
Fan, J., Rigby, J. K., Q., J., 1990, The Permian reels o f South China and comparisons
with the Permian reef complex of the Guadalupe Mountains, west Texas and New
Mexico. Brigham Young University, Geology Studies, v. 36, 15-56.
Faure, K., de Wit, M. J., and Willis, J. P., 1995, Late Permian global coal hiatus linked to
13 C-depleted C02 flux into the atmosphere during the final consolidation of
Pangaea. Geology, v. 23, p. 507-510.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
289
Fischer, A. G., 1964, Brackish oceans as the cause o f the Permo-Triassic faunal crisis. In:
Naim, A. E. M., (ed.), Problems in palaeoclimatology, p. 566-574.
Flugel, E., 1994, Pangean shelf carbonates: controls on paleoclimatic significance of
Permian and Triassic reefs. Geological Society of America Special Papers, v.
288,247-266.
Fraiser, M. L., and Bottjer, D.J., 1999, Microgastropods as opportunists during the biotic
recovery from the end-Permian mass extinction: Geological Society o f America,
Abstracts with Programs, v. 31 (7), p. 472.
Fraiser, M. L., and Bottjer, D. J., 2000, The U-shaped trace fossil Arenicolites: burrow of
an opportunist during the biotic recovery from the end-Permian mass extinction:
Geological Society of America, Abstracts with Programs, v. 32 (7), p. 368.
Francis, J. E., 1994, Palaeoclimates of Pangea - geological evidence, In: Embry, A. F.,
Beauchamp, B., and Glass, D. (eds.), Pangea: global environments and resources,
Canadian Society of Petroleum Geologists, Memoir 17, p. 265-274.
Gordon, W. A., 1975, Distribution by latitude ofPhanerozoic evaporite deposits. Journal
of Geology, v. 83, p. 671-684.
Hallam, A., 1991, Why was there a delayed radiation after the end-Palaeozoic extinction?
Historical Biology, v. 5, p. 257-262.
Hallam, A., and Wignall, P.B., 1997, Mass extinctions and their aftermath, Oxford
University Press, New York, 320 p.
Harries, P. J., Kauffman, E. G., and Hansen, T. A., 1996, Models for biotic survival
following mass extinction. In: Hart, M. B., (ed.), Biotic Recovery from Mass
Extinction Events, Geological Society Special Publication, No. 102, p. 41-60
Hintze, L. F., 1988, Triassic (Phase IV), In: Kowallis, B. J. (ed.), Geologic History of
Utah, Brigham Young University Geology Studies Special Publication 7.
Isozaki, Y., 1994, Superanoxia across the Permo/Triassic boundary: recorded in accreted
deep-sea pelagic chert in Japan. Canadian Society o f Petroleum Geologists,
Memoir, v. 17, p. 805-812.
Jablonski, D., Sepkoski, J. J., Jr., Bottjer, D. J., and Sheehan, P. M., 1983,
Onshore-offshore patterns in the evolution ofPhanerozoic shelf communities.
Science, v. 222, p. 1123-1125.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
290
Jin, Y., Wang, Y., Wang, W., Shang, Q., Cao, C., and Erwin, D., 2000, Pattern of marine
mass extinction near the Permian-Triassic boundary in South China. Science, v.
289, p. 432-436.
Jin, Y., Zhang, J., and Shang, Q., 1994, Two phases of the end-Permian mass extinction.
Canadian Society of Petroleum Geologists, Memoir, v. 17, p. 813-822.
Knoll, A. H., Bambach, R. K., Canfield, D. E., and Grotzinger, J. P., 1996, Comparative
earth history and Late Permian mass extinction. Science, v. 273, p. 452-457.
Kozur, H., 1991, Permian deep-water ostracods from Sicily (Italy) Part 2: Biofacial
evaluation and remarks to the Silurian to Triassic paleopsychrospheric ostracods.
Geologisch-Palaontologische Mitteilungen Innsbruck, v. 3, 25-38.
Levinton, J. S., 1970, The paleoecologicai significance of opportunistic species. Lethaia,
v. 3 (1), p. 69-78.
Nakazawa, K., and Runnegar, B., 1973, The Permian-Triassic boundary: a crisis for
bivalves?, In: Logan, A., and Hills, L. V., (eds.), The Permian and Triassic
systems and their mutual boundary, Canadian Society o f Petroleum Geologists,
Memoir 2, p. 608-621.
Nance, R. D. and Murphy, J. Brendan, 1994, Orogenic style and the configuration of
supercontinents, In: Embry, A. F., Beauchamp, B., and Glass, D. (eds.), Pangea:
global environments and resources, Canadian Society o f Petroleum Geologists,
Memoir 17, p. 49-65.
Parrish, J. T., 1993, Climate of the Supercontinent Pangea. Journal of Geology, v. 101,
215-233.
Pauli, R. K. and Pauli, R. A., 1994, Shallow marine sedimentary facies in the earliest
Triassic (Griesbachian) Cordilleran miogeocline, USA. Sedimentary Geology, v.
93, p. 181-191.
Perry, D. G., and Chatterton, B. D., 1979, Late Early Triassic brachiopod and conodont
fauna, Thaynes Formation, southeastern Idaho. Journal of Paleontology, v. 53,
307-319.
Pianka, E. R , 1970, On r- and K-selection. American Naturalist, v. 104, p. 592-597.
Raup, D. M., 1979, Size of the Permo-Triassic bottleneck and its evolutionary
implications. Science, v. 206, 217-218.
Renne, P.R. and Basu, A. R., 1991, Rapid eruption of the Siberian Traps flood basalts at
the Permo-Triassic boundary. Science, v. 253, p. 176-179.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
291
Renne, P. R., Zhang, Z„, Richardson, M.A., Black, M. T., and Basu, A. R., 1995,
Synchrony and causal relations between Permo-Triassic boundary crises and
Siberian flood volcanism. Science, v. 269, 1413-1416.
Riefl D. M. and Slatt, R. M., 1979, Red bed members of the Lower Triassic Moenkopi
Formation, southern Nevada, sedimentology and paleogeography of muddy tidal
deposits. Journal o f Sedimentary Petrology, v. 49, p. 869-889.
Rigby, J. K., and Senowbari-Daryan, B., 1995, Permian sponge biogeography and
biostratigraphy, In: Scholle, P.A., Peryt, T.M., and Ulmer-Scholle, D. S., (eds.),
The Permian of northern Pangea 1, p. 153-166.
Rodland, D. L ., 1999, Paleoenvironments and paleoecology o f the disaster taxon Lingula
in the aftermath of the end-Permian mass extinction, [Master’s thesis], University
of Southern California, 113 p.
Ross, C. A. and Ross, J. R. P., 1995, Permian sequence stratigraphy. In: Scholle, P.A.,
Peryt, T.M., and Ulmer-Scholle, D. S., (eds.), The Permian of northern Pangea 1
p. 98-123.
Sano, H., and Nakashima, K., 1997, Lowermost Triassic (Griesbachian) microbial
bindstone-cementstone facies, southwest Japan. Facies, v. 36, p. 1-24.
Schindewolf, O. H., 1954, Uber die moglichen Ursachen der grossen erdgeschichtlichen
Faunenschnitte. Neues Jahrbuch fiir Geologie und Palaontologie Monatshefte, v.
1954, p. 457-465.
Schubert, J. K. and Bottjer, D. J., 1992, Early Triassic stromatolites as post-mass
extinction disaster forms. Geology, v. 20, p. 883-886.
Schubert, J. K. and Bottjer, D. J., 1995, Aftermath of the Permian-Triassic mass extinction
event: Paleoecology of Lower Triassic carbonates in the western USA:
Palaeogeography, Palaeoclimatology, Palaeoecology, v. 116, p. 1-39.
Schubert, J. K., Bottjer, D. J., and Simms, M. J., 1992, Paleobiology of the oldest
articulate crinoid. Lethaia, v. 25, p. 97-110.
Selhvood, B. W., 1973, Carbonate coastal accretion in an area of longshore transport, NE
Qatar, Persian Gulf. In: Purser, B. H., (ed.), The Persian Gulf, Holocene
carbonate sedimentation and diagenesis in a shallow epicontinental sea, p.
179-192.
Sepkoski, J. J., Jr., 1986, Phanerozoic overview of mass extinctions, In: Raup, D. M.,
and Jablonski, D., (eds.), Patterns and processes in the history of life, p. 277-295.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
292
Shinn, E. A., Lloyd, R. M., and Ginsburg, R. N., 1969, Anatomy of a modem carbonate
tidal flat. Journal of Sedimentary Petrology, v. 39 (3), p. 1202 - 1228.
Smith, R. L., 1992, r-selection and K-selection,p.209-210, In: Elements of Ecology,
Harper Collins Publishers.
Stanley, S. M., 1984, Temperature and biotic crises in the marine realm. Geology, v. 12,
p. 205-208.
Stanley, S. M., 1988, Paleozoic mass extinctions: shared patterns suggest global cooling
as a common cause. American Journal o f Science, v. 288, p. 334-352.
Stiling, P., 1999, Life History Variation. In: Ecology Theories and Applications, p.
141-146.
Stokes, W. L., 1986, The Triassic Period, In: Geology of Utah, Occasional Paper
Number 6, Utah Museum ofNatural History and Utah Geological and
Mineral Survey, p. 105-114,.
Tappan, H., and Loeblich, A. R., 1988, Foraminiferal evolution, diversification, and
extinction Journal o f Paleontology, v. 62, p. 695-714.
Taylor, P. D., and Larwood, G. P., 1988, Mass extinctions and the pattern ofbryozoan
evolution, In: Larwood, G. P., (ed.), Extinction and survival in the fossil record,
Systematics Association Special Volume, 34, p. 99-119.
Teichert, C., 1990, The Permian-Triassic boundary revisited, In: Kauffman, E. G., and
Walliser, O. H., (eds.), Extinction events in Earth history, p. 199-238.
Tosk, T. A., and Anderson, K. A., 1988, Late Early Triassic foraminifers from possible
dysaerobic to anaerobic paleoenvironments of the Thaynes Formation, southeast
Idaho. Journal ofForaminiferal Research, v. 18, p. 286-301.
Tucker, M. E. and Wright, V. P., 1990, Carbonate depositional systems I: marine
shallow-water and lacustrine carbonates. In: Carbonate Sedimentology, p. 101 -
227.
Twitchett, R., 1998, ‘And the small shall inherit the Earth...’, The Palaeontological
Association 42nd Annual Meeting, University of Portsmouth: Abstracts and
Programs, p. 25.
Valentine, J. W., and Moores, E. M., 1970, Plate-tectonic regulation o f faunal diversity
and sea level: a model. Nature, v. 228, p. 657-659.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
293
Valentine, J. W., and Moores, E. M., 1972, Global tectonics and the fossil record. Journal
of Geology, v. 80, p. 167-184.
Valentine, J. W., and Moores, E. M., 1973, Provinciality and diversity across the
Permian-Triassic boundary. In: Logan, A., and Hills, L. V., (eds.), The Permian
and Triassic systems and their mutual boundary, Memoir 2, Canadian Society of
Petroleum Geologists, p. 759-766.
Waage, K. M., 1968, The type Fox Hills Formation, Cretaceous (Maestrichtian), South
Dakota. In: Part 1. Stratigraphy and Paleoenvironments, 171 p., Peabody
Museum Bulletin ofYale University, Bulletin 27.
Wignall, P. B., 2001, End Permian Extinction. In: Briggs, D.E.G. and Crowther, P.R.,
(eds.).Paleobiology II, Blackwell Scientific Publishers, Boston.
Wignall, P.B., and Hallam, A., 1996, Facies change and the end-Permian mass extinction
in S. E. Sichuan, China. Palaios, v. 11, p. 587-596.
Wignall, P. B. and Twitchett, R. J., 1996, Oceanic anoxia and the end Permian mass
extinction. Science, v. 272, p. 1155-1158.
Xu, G., and Grant, R. E., 1992, Permo-Triassic brachiopod succession and events in
South China, p.98-108 In: Sweet, W., C., Yang, Z., Dickins, J. M., and Yin, H.,
(eds.), Permo-Triassic boundary events in the eastern Tethys, Cambridge
University Press.
Yang, F., 1993, Biotic mass extinction and biotic alteration at the Permo-Triassic
boundary. Ammonoids., In: Yang, Z., Wu, S., Yin, FL, Xu, G., Zhang, K., and
Bi, X, (eds.), Permo-Triassic events of South China, Geological Publishing House,
Beijing, p. 102 8,
Yin, H., 1985, Bivalves near the Permian-Triassic boundary in South China. Journal of
Paleontology, v. 59, p. 572-600.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
294
APPENDIX A: Results from thin section analyses for the twenty intervals from the seven
Sinbad Limestone Member localities that were disaggregated. Information
in the table includes: locality, interval within the stratigraphic column each
interval was located, facies, and the ranges in % microgastropod material,
bivalve material, echinoderm material, peloids, ooids, and porosity and
matrix, and rock type. Abbreviations are: SL-RC - Sinbad Limestone
Member, Roadcut Locality; SL-BS - Sinbad Limestone Member, Batten
and Stokes Locality; SL-JB - Sinbad Limestone Member, Jackass Benches
Locality; SL-BB - Sinbad Limestone Member, Black Box Locality; SL-J -
Sinbad Limestone Member, Junction Locality; SL-FC - Sinbad Limestone
Member, Fish Creek Locality; SL-MM - Sinbad Limestone Member,
Miners Mountain Locality; SC - skeletal calcarenite; DC - dolomitized
calcarenite; A - Lithofacies A; B - Lithofacies B; D - Lithofacies D.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission
Thin Section Analyses fo r Sinbad Lim estone M em ber Localities
range In % range in % range In % range In range In range In rock
microgastropod bivalve echlnoderm % % % Identification
locality Interval facies material material material pelolds ootds matrix and porosity
SL-RC 1 SC 0 0 0 59 1 40 peloidal packstone
SL-RC 8 SC 1 to 10 40 to 49 0 0 to 5 0 50 skeletal packstone
SL-BS 1 SC 0 0 0 97 3 0 peloidal wackeslone
SL-BS 6 SC 0 40 to 50 1 0 0 15 to 21 skeletal packstone
SI-JB 1 SC 0 0 0 70 10 20 peloidal wackestone
SL-JB 0 SC 15 to 25 25 to 40 0 5 to 10 0 30 to 50 skeletal packstone
SL-JB 13 DC 5 1 to 15 0 5 40 to 49 35 to 55 oolitic wackstone
SL-BB 1 SC 0 5 0 59 to 60 0 30 to 40 peloidal wackestone
SL-BB 13 SC 0 20 0 0 0 80 skeletal wackestone
SL-J 4 SC 1 to 5 45 to 50 10 0 0 40 to 50 skeletal packstone
SL-J 8 SC 10 to 20 40 to 49 1 to 20 0 0 40 skeletal packstone
SL-FC 1 A 0 10 0 0 0 90 skeletal wackstone
SL-FC 9 B 5 to 10 20 to 35 0 15 to 20 0 45 to 50 skeletal packstone
SL-FC 13 B 25 19 to 50 1 5 to 10 0 39 to 50 skeletal packstone
SL-FC 16 D 25 to 30 25 to 30 3 0 0 47 to 70 skeletal packstone
SL-FC 21 D 10 20 to 40 0 1 20 to 30 35 to 60 skeletal packstone
SL-MM 3 A 0 0 0 0 0 100 mudstone
SL-MM 9 A 0 0 0 45 to 60 5 to 10 30 to 50 peloidal packstone
SL-MM 17 B 20 to 35 35 to 50 0 0 0 30 to 35 skeletal packstone
SL-MM 21 D 15 to 40 30 to 40 5 0 0 20 to 50 skeletal packstone
296
APPENDIX B: Faunal abundance data from all Sinbad Limestone Member localities in
southern Utah. The following is indicated in the table: locality, interval of
the stratigraphic column examined, distance each interval is from the base
of the Sinbad Limestone Member at that locality, facies within which each
interval is located, ranking, number of gastropods > 2/3 whole, number of
gastropods < 2/3 whole, number of bivalves > 1/2 whole, number of
bivalves < 1/2 whole, number o f bivalve individuals, number of
scaphopods, number of Lingula individuals, and number of crinoids
(though many crinoid ossicles were noted, the ossicles were counted as one
crinoid individual because 1, 500 visible ossicles represents one individual
(Schubert et al, 1992)). Abbreviations are: SL-RC - Sinbad Limestone
Member, Roadcut Locality; SL-BS - Sinbad Limestone Member, Batten
and Stokes Locality; SL-JB - Sinbad Limestone Member, Jackass Benches
Locality; SL-BB - Sinbad Limestone Member, Black Box Locality; SL-J -
Sinbad Limestone Member, Junction Locality; SL-FC - Sinbad Limestone
Member, Fish Creek Locality; SL-MM - Sinbad Limestone Member,
Miners Mountain Locality; SC - skeletal calcarenite; DC - dolomitized
calcarenite; A - Lithofacies A; B - Lithofacies B; D - Lithofacies D,
TNTC - too numerous to count. The data comes from five-bag samples
from twenty intervals from seven localities that were disaggregated in the
laboratory. See the Methods section for a description o f the analysis.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
B u lk S a m p le A n a ly s e s for S in b a d L im e s to n e M e m b e r Localities
locality Interval
distance from
base of Sinbad facies ranking
#of
gastropods
> 2/3 whole
#of
gastropods
< 2/3 whole
#of
bivalves
> 1/2 whole
#of
bivalves
< 1/2 whole
#of
bivalve
Individuals
scapho
pods
Unguis
individuals
echino-
derms
SL-RC 1 0.5 m SC 3 33 41 46 87 23
SL-RC 8 2.8 m SC 1 104 13 45 131 23 213 2
SL-BS 1 0.3 m SC 1 196 321 171 274 86
SL-BS 6 2.8 m SC 3 TNTC TNTC TNTC TNTC TNTC
SI-JB 1 1.9 m SC 3 24 16 52 61 26
SL-JB 6 2.8 m SC 3 81 4 131 114 66 29 5
SL-JB 13 13.25 m DC 2 28 17 173 111 87
SL-BB 1 0.94 m SC 1 99 86 20 12 10
SL-BB 13 2.8 m SC 2 1 0 268 125 134 1 1
SL-J 4 1.9 m SC 2 90 11 409 TNTC 205 33
SL-J 8 4.4 m SC 2 9 6 66 60 33
SL-FC 1 1.5 m A 2 8 48 70 51 35
SL-FC 9 4.8 m B 2 24 13 142 TNTC 71 1
SL-FC 13 6.9 m B 2 9 8 84 19 42 1 1
SL-FC 16 11.5 m D 2 0 1 44 13 22 1
SL-FC 21 14.8 m D 2 1 0 189 11 95
SL-MM 3 2.6 m A 1 3 4 0 0 0
SL-MM 9 4.8 m A 2 13 5 45 9 23
SL-MM 17 12 m B 1 83 59 106 169 53 1
SL-MM 21 14.8 m D 2 2 2 69 3 35
297
298
APPENDIX C: Preservation and abundance of microgastropods and bivalves for all
seven Sinbad Limestone Member Localities. The data comes from five-bag
samples from twenty intervals at seven localities that were disaggregated
in the laboratory. See the Methods section for a description of the analysis.
Information given in the tables includes: locality name, interval examined,
and focies in which the interval is located. For microgastropods, the
number of internal molds, external molds and casts >2/3 whole, the number
of internal molds, external molds and casts <2/3 whole, and the total
number of microgastropods is given for each interval. For bivalves, the
number o f internal molds, external molds and casts >1/2 whole, the number
of internal molds, external molds and casts <1/2 whole, and the total
number of bivalves is given for each interval. Each interval’s ranking based
on the relative abundances of microgastropods and bivalves is given, too.
Abbreviations include: TNTC - too numerous to count.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
299
S in b ad L im esto n e Member - R o ad cu t Locality
INTERVAL 1 (skeletal calcarenite)
bivalves
microgastropods > 1/2 whole < 1/2 whole
internal molds 14 6
> 2/3 whole < 2/3 whole external mold: 12 55
internal molds 7 22 casts 20 26
external mold! 10 8
casts 16 11 total number of
whole bivalve valves: 46
total number of
whole miarogastropods: 33 total number of
bivalve individuals: 23
ran king: 3
IN T E R V A L 8 (skeletal calcarenite)
bivalves
microgastropods > 1/2 whole < 1/2 whole
internal molds 10 2
> 2/3 whole< 2/3 whole external mold! 0 0
internal molds 12 3 casts 35 129
external m olds 2 3
casts 90 7 total number of
whole bivalve valves: 45
total number of
whole microgastropods: 104 total number of
bivalve individuals: 23
ran king: 1
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
300
S in b ad L im estone M em ber - B atten an d SIcokes Locality
IN T E R V A L 1 (skeletal calcarenite)
bivalves
microgastropods > 1/2 whole < 1/2 whole
internal molds 99 67
> 2/3 whole < 2/3 whole external molds 29 82
internal molds 142 90 casts 43 125
external molds 11 19
casts 43 212 total number of
whole bivalve valves: 171
tots! number of
whole microgastropods: 196 total number of
bivalve individuate: 86
ran king: 1
IN T E R V A L 6 (skeletal calcarenite)
bivalves
microgastropods > 1/2 whole < 1/2 whole
internal molds TNTC TNTC
> 2/3 whole < 2/3 whole external molds TNTC TNTC
internal molds TNTC TNTC casts TNTC TNTC
external molds TNTC TNTC
casts TNTC TNTC tota! number of
whole bivalve valves: TNTC
total number of
whole microgastropods: TNTC total number of
bivalve individuate: TNTC
ranking: 3
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
301
S in b ad L im esto n e Member - J a c k a s s B e n c h e s Locali
INTERVAL 1 (skeletal calcarenite)
bivalves
microgastropods > 1/2 whole < 1/2 whole
internal molds
> 2/3 whole < 2/3 whole external molds
internal molds casts
external molds
casts total number of
whole bivalve valves:
total number of
whole microgastropods: total number of
bivalve individuate:
ranking: 3
INTERVAL 6 (skeletal calcarenite)
> 1/2 whole < 1/2 whole
internal molds
> 2/3 whole < 2/3 whole external mold;
internal molds 120 casts 114
external molds
casts total number of
whole bivalve valves: 131
total number of
whole microgastropods: total number of
bivalve individuals:
ranking:
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
302
S in b ad L im esto n e Member - Jackass B e n c h e s Locality
INTERVAL 13 (dotomitized calcarenite)
bivalves
m icrogastropods > 1/2 whole < 1/2 whole
internal molds 10 1 0
> 2/3 whole < 2/3 whole external mold: 0 1
internal molds 21 4 casts 163 1 0 0
external molds 3 4
casts 4 9 total number of
whole bivalve valves: 173
total number of
whole microgastropods: 28 total number of
bivalve individuals: 87
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
303
S in b ad Lim estone M em ber - B lack B ox Locality
INTERVAL 1 (skeletal calcarenite)
bivalves
m icrogastropods > 1/2 whole < 1 1 2 whole
internal molds 5 1
> 2/3 whole < 2/3 whole external molds 4 1
internal molds 27 3 casts 11 10
external mold: 12 8
casts 60 75 total number of
whole bivalve valves: 20
total number of
whole microgastropods: 9 9 total number of
bivalve individuals: 10
ranking: 1
INTERVAL 13 (skeletal calcarenite)
bivalves
m icrogastropods > 1/2 whole < 1/2 whole
internal molds 73 30
> 2/3 whole < 2/3 whole external molds 25 0
internal molds 0 0 casts 170 95
external mold: 0 0
casts 1 0 total number of
whole bivalve valves: 268
total number of
whole microgastropods: 1 total number of
bivalve individuals: 134
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
304
S in b ad L im esto n e M em ber - Ju n c tio n Locality
INTERVAL 4 (skeletal calcarenite)
bivalves
m icrogastropods > 1/2 whole < 1/2 whole
internal molds 3 0
> 2/3 whole < 2/3 whole external molds 0 0
internal molds 6 5 casts 406 TN TC
external molds 2 0
casts 85 6 total number of
whole bivalve valves; 409
total number of
whole microgastropods: 90 total number of
bivalve individuals: 205
ranking: 2
INTERVAL 8 (skeletal calcarenite)
bivalves
m icrogastropods > 1/2 whole < 1/2 whole
internal molds 1 0
> 2/3 whole < 2/3 whole external molds 0 2
internal molds 8 0 casts 6 5 58
external m olds 0 3
casts 1 3 total number of
whole bivalve valves: 66
t o ta l number o f
whole microgastropods: 9 total number of
bivalve individuals: 33
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
305
S in b ad L im esto n e Member - Fish C reek Locality
INTERVAL 1 (lithofacies A)
bivalves
m icrogastropods > 1/2 whole < 1/2 whole
internal molds 33 13
> 2/3 whole < 2/3 whole external molds 11 13
interna! molds 8 32 casts 26 25
external molds 0 10
casts 0 6 total number of
whole bivalve valves: 70
total number of
whole microgastropods: 8 total number of
bivalve individuals: 35
ranking: 2
INTERVAL 9 (lithofacies B)
bivalves
m icrogastropods > 1/2 whole < 1/2 whole
internal molds 20 0
> 2/3 whole < 2/3 whole external molds 0 0
internal molds 1 2 casts 122 TNTC
external molds 6 1
casts 17 1 0 total number of
whole bivalve valves: 142
total number of
whole microgastropods: 24 total number o f
bivalve individuals: 71
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
306
S in b ad L im esto n e M em ber - F ish C reek Locali
INTERVAL 13 (lithofacies B)
bivalves
< 1/2 whole > 1/2 whole
internal molds
> 2/3 whole < 2/3 whole external molds
internal molds casts
external mold:
casts total number © f
whole Wvalve valves:
total number of
whole microgastropods: total number of
bivalve individuals:
ranking
INTERVAL 16 (lithofacies D)
bivalves
> 1/2 whole < 1/2 whole
internal molds
> 2/3 whole < 2/3 whole external molds
internal molds casts
external mold:
casts
total number of
whole bivalve valves: 44
total number of
whoie microgastropods: total number of
bivalve individuals:
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
307
S in b ad L im esto n e Member - F ish C reek Locality
INTERVAL 21 (lithofacies D)
microgastropods
> 2/3 whole < 2/3 whole
internal molds 1 0
external mold! 0 0
casts 0 0
total number of
whole microgastropods:_____ 1
bivalves
> 1/2 whole < 1/2 w hole
internal molds 141 4
external molds 4 4 4
casts 4 3
total number of
whole bivalve valves: 189
total number of
bivalve individuals: 95
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
308
S in b ad Limestone M em ber - M iners M ountain Locali
INTERVAL 3 (lithofacies A)
bivalves
> 1/2 whole < 1/2 whole
internal molds
> 2/3 whole < 2/3 whole external molds
internal molds casts
external mold:
casts iota! number ® f
whole bivalve valves:
total number of
whole microgastropods: total number of
bivalve individuals:
ranking: 1
INTERVAL 9 (lithofacies A)
bivalves
> 1/2 whole < 1/2 whole
internal molds
> 2/3 whole < 2/3 whole external molds
internal molds casts
external molds
casts total number of
whole bivalve valves: 45
total number of
whole microgastropods: total number of
bivalve individuals:
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
309
S in b ad L im estone Member - Miners M ountain Locality
INTERVAL 17 (lithofacies B)
bivalves
microgastropods > 1/2 whole < 1/2 whole
internal molds 9 0
> 2/3 whole < 2/3 whole external molds 2 7
internal molds 29 30 casts 95 162
external molds 0 10
casts 54 19 total number of
whole bivalve valves: 106
total number of
whole microgastropods: 83 total number of
bivalve individuals: 53
ranking: 1
INTERVAL 21 (lithofacies D)
bivalves
m icrogastropods > 1/2 whole < 1/2 whole
internal molds 3 0
> 2/3 whole < 2/3 whole external molds 0 0
internal molds 0 0 casts 66 3
external molds 0 0
casts 2 2 total number of
whole bivalve valves: 69
total number of
whole microgastropods: 2 total number of
bivalve individuals: 35
ranking: 2
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
310
APPENDIX D: Size data for microgastropods from all Sinbad Limestone Member
localities. Included in the chart are: locality names, intervals examined,
facies, ranking, and sizes of whole microgastropods in millimeters.
Intervals not included in the table either contained no microgastropods or
the microgastropods were too difficult to measure.
R eproduced with perm ission of the copyright owner. Further reproduction prohibited without perm ission.
Reproduced w ith permission o f th e copyright owner. Further reproduction prohibited without permission.
Size Data for M icrogastropods from Sinbad L im e sto n e Member Localities
Data from Disaggregation
l.._...-. -................
sizes of gastropods In millimeters J
locality Interval facies ranking 0-0.9 1-1.9 2-2.9 3-3.9 4-4.9 9-5.9 6-5.9 7-7.9 8-8.9 9-9.9 10 -10.9 11-11.8 12 -12.9 13-13.9 14-14.9 15 - 15.9 16 -16.9 17 -17.9
SL-RC 1 SC 3 0 3 5 4 1 5 1
SL-RC 8 SC 1 43 9 1 1
SL-BS 1 s c 1 1 31 28 16 6 2 3 1
SI-JB 1 s c 3 1 4 2 3 3 2
SL-JB 6 s c 3 17 6
SL-JB 13 DC 2 1 1 4 2 3
SL-BB 1 SC 1 2 18 13 4 1 1
SL-J 4 SC 2 9 32 2 1 1 1
SL-J 8 s c 2 1 3 2
SL-FC 1 A 2 1 3 3 1 2
SL-FC 13 B 2 3 1
3 A 1 2 1
9 A 2 3 2 1
17 B 1 37 11 3 1
Linked assets
University of Southern California Dissertations and Theses
Conceptually similar
PDF
Marine paleoecology during the aftermath of the end-Permian mass extinction
PDF
Biotic recovery from the end-Permian mass extinction: Analysis of biofabric trends in the Lower Triassic Virgin Limestone, southern Nevada
PDF
Paleoenvironments and paleoecology of the disaster taxon Lingula in the aftermath of the end-Permian mass extinction: Evidence from the Dinwoody Formation (Griesbachian) of southwestern Montana...
PDF
Paleoecology and depositional paleoenvironments of Pleistocene nearshore deposits, Las Animas, Baja California Sur, Mexico
PDF
The Triassic organic-rich flat clam biotope: A synthesis of paleoecological and climate modeling analyses
PDF
Barnacles as mudstickers? The paleobiology, paleoecology, and stratigraphic significance of Tamiosoma gregaria in the Pancho Rico Formation, Salinas Valley, California
PDF
Helicoplacoid echinoderms: Paleoecology of Cambrian soft substrate immobile suspension feeders
PDF
The origin of enigmatic sedimentary structures in the Neoproterozoic Noonday dolomite, Death Valley, California: A paleoenvironmental, petrographic, and geochemical investigation
PDF
Evolutionary paleoecology and taphonomy of the earliest animals: Evidence from the Neoproterozoic and Cambrian of southwest China
PDF
The structure and development of Middle and Late Triassic benthic assemblages
PDF
The unusual sedimentary rock record of the Early Triassic: Anachronistic facies in the western United States and southern Turkey
PDF
Lower Cambrian trace fossils of the White-Inyo Mountains, eastern California: Engineering an ecological revolution
PDF
Structure and origin of echinoid beds, unique biogenic deposits in the stratigraphic record
PDF
Seafloor precipitates and carbon-isotope stratigraphy from the neoproterozoic Scout Mountain member of the Pocatello Formation, Southeast Idaho: Implications for neoproterozoic Earth history
PDF
Oxygen-related biofacies in slope sediment from the Western Gulf of California, Mexico
PDF
Large epifaunal bivalves from Mesozoic buildups of western North America
PDF
Paleoecology of the Lower Triassic virgin member (Moenkopi Formation), southeastern Nevada and southwestern Utah
PDF
Reinterpreting the tectono-metamorphic evolution of the Tonga Formation, North Cascades: A new perspective from multiple episodes of folding and metamorphism
PDF
Rebound from the Permian-Triassic mass extinction event: Paleoecology of Lower Triassic carbonates in the western U.S.
PDF
Morphologic trends in Permo-Triassic gastropods: A theoretical morphology approach
Asset Metadata
Creator
Fraiser, Margaret Lee
(author)
Core Title
Paleoecology and paleoenvironments of early Triassic mass extinction biotic recovery faunas, Sinbad Limestone Member, Moenkopi Formation, south-central Utah
Degree
Master of Science
Degree Program
Geological Sciences
Publisher
University of Southern California
(original),
University of Southern California. Libraries
(digital)
Tag
Geology,OAI-PMH Harvest,paleoecology,paleontology
Language
English
Contributor
Digitized by ProQuest
(provenance)
Permanent Link (DOI)
https://doi.org/10.25549/usctheses-c16-39342
Unique identifier
UC11336627
Identifier
1407909.pdf (filename),usctheses-c16-39342 (legacy record id)
Legacy Identifier
1407909.pdf
Dmrecord
39342
Document Type
Thesis
Rights
Fraiser, Margaret Lee
Type
texts
Source
University of Southern California
(contributing entity),
University of Southern California Dissertations and Theses
(collection)
Access Conditions
The author retains rights to his/her dissertation, thesis or other graduate work according to U.S. copyright law. Electronic access is being provided by the USC Libraries in agreement with the au...
Repository Name
University of Southern California Digital Library
Repository Location
USC Digital Library, University of Southern California, University Park Campus, Los Angeles, California 90089, USA
Tags
paleoecology
paleontology