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The geochemical record of the last 17,000 years in the Guaymas Basin, Gulf of California

Chemical Geology

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DOI: 10.1016/j.chemgeo.2006.02.017

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Abstract

Sediments deposited on the western slope of the Guaymas Basin in the central Gulf of California are composed predominantly of detrital clastic material and biogenic silica (biopal), with minor organic material (average of 2.8% organic carbon) and calcium carbonate. The CaCO3 is derived from calcareous plankton and is highly variable ranging from 0% to 16%. In general, the CaCO3 content of the sediments varies inversely with the biopal content, reflecting the relative abundance of calcareous and siliceous plankton in the photic zone. Siliceous plankton dominate when winds are predominantly out of the northwest producing strong upwelling. Calcareous plankton indicates weak southeasterly winds that bring warm, tropical Pacific surface water into the Gulf. Based mainly on relative abundances of biopal and CaCO3, the sediments deposited over the last 17,000 years in the western Guaymas Basin can be divided into five intervals. In general, the sediments in the intervals with high biopal and low CaCO3 are laminated, but this is not always true. Unlike most other continental margins of the world with well-developed oxygen minimum zones where highest concentrations of organic carbon and redox-sensitive trace metals occur in laminated sediments, the laminated sediments on the anoxic slope of the western Guaymas Basin do not always have the highest concentrations of organic carbon and trace metals such as Mo and Cd.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
The geochemical record of the last 17,000 years in the Guaymas Basin, Gulf of California
Series title:
Chemical Geology
DOI:
10.1016/j.chemgeo.2006.02.017
Volume
232
Issue:
3-4
Year Published:
2006
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Chemical Geology
First page:
87
Last page:
98
Number of Pages:
12