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Western Equatorial Atlantic Sedimentation: A Study of Magnetic Properties
Emily Mortazavi
University of Southern California
December 2012
Object Description
| Title | Western equatorial Atlantic sedimentation: a study of rock magnetic properties |
| Author | Mortazavi, Emily S. |
| Author email | emily.mortazavi@gmail.com;emortaza@usc.edu |
| Degree | Master of Science |
| Document type | Thesis |
| Degree program | Geological Sciences |
| School | College of Letters, Arts And Sciences |
| Date defended/completed | 2012-10-24 |
| Date submitted | 2012-11-21 |
| Date approved | 2012-11-21 |
| Restricted until | 2012-11-21 |
| Date published | 2012-11-21 |
| Advisor (committee chair) | Lund, Steven P. |
| Advisor (committee member) |
Berelson, William M. Corsetti, Frank A. |
| Abstract | The ANACONDAS Cruises I and II set out to investigate the Amazon plume (the zone of low salinity discharge from the Amazon River) and its effects on the oceanic carbon cycle. To understand sedimentation in the region, 30 multicores and 7 gravity cores were collected from the Amazon Fan, the adjacent Continental Slope and the Demerara Abyssal Plain. The magnetic properties, weight percent carbonate, weight percent organic carbon and δ13C were examined for the purposes of building a regional correlation, understanding the drivers of the regional sedimentation patterns and the magnetic signal. ❧ A regional correlation was established using 24 tie points, including data from anhysteretic remnant magnetization (ARM), saturated isothermal remnant magnetization (SIRM), weight percent CaCO3, δ13C and 8 features in the magnetic susceptibility record. A broad low in magnetic susceptibility during the mid-Holocene was one of the most regionally continuous marker units used for correlation. The primary cause of the low seen in magnetic susceptibility was determined to be dilution by carbonate. ❧ Regional average sedimentation rates for the Holocene were determined using 14C dates and the established correlations. A decrease in sedimentation occurs in the lower portion of the record. ❧ Station 13 has the highest sedimentation rates regionally with the most dramatic decrease in rates and condensed sections in distal stations to the northeast and northwest. Rates of sedimentation to the south of Station 13 while depressed are not as drastic as the northerly sites. ❧ Of particular note, an indurated crust, varying in depth from 33-57cm, was found in many cores throughout the region. The crust seems to have little effect on the overall magnetic record and when compared to other stratigraphic markers, with some observed variation in the hematite fraction. |
| Keyword | rock magnetics; sedimentation; Holocene; Amazon Fan |
| Language | English |
| Part of collection | University of Southern California dissertations and theses |
| Publisher (of the original version) | University of Southern California |
| Place of publication (of the original version) | Los Angeles, California |
| Publisher (of the digital version) | University of Southern California. Libraries |
| Provenance | Electronically uploaded by the author |
| Type | texts |
| Legacy record ID | usctheses-m |
| Contributing entity | University of Southern California |
| Rights | Mortazavi, Emily S. |
| Physical access | 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 author, as the original true and official version of the work, but does not grant the reader permission to use the work if the desired use is covered by copyright. It is the author, as rights holder, who must provide use permission if such use is covered by copyright. The original signature page accompanying the original submission of the work to the USC Libraries is retained by the USC Libraries and a copy of it may be obtained by authorized requesters contacting the repository e-mail address given. |
| Repository name | University of Southern California Digital Library |
| Repository address | USC Digital Library, University of Southern California, University Park Campus MC 7002, 106 University Village, Los Angeles, California 90089-7002, USA |
| Repository email | cisadmin@dots.usc.edu |
| Archival file | uscthesesreloadpub_Volume4/etd-MortazaviE-1323.pdf |
Description
| Title | Page 1 |
| Contributing entity | University of Southern California |
| Repository email | cisadmin@dots.usc.edu |
| Full text | Western Equatorial Atlantic Sedimentation: A Study of Magnetic Properties Emily Mortazavi University of Southern California December 2012 |
