Organic geochemical character of opal-rich sediments in light-dark cycles near the Pliocene-Pleistocene boundary in Deep-Sea Drilling Project Site 532, Walvis Ridge

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doi: 10.1029/PA001i004p00567
Author(s): Meyers, Philip A.; Dunham, Keith W.; Rau, Greg H.
Author Affiliation(s): Primary:
Univ. Mich., Oceanogr. Program, Ann Arbor, MI, United States
Other:
Univ. Calif., Santa Cruz, United States
Volume Title: Special section; Milankovitch cycles through geologic time
Volume Author(s): Arthur, Michael A., editor; Garrison, Robert E.
Source: Paleoceanography, 1(4), p.567-575; Cyclic and periodic events in stratigraphy, evolution and the geologic record, Princeton, NJ, May 1985, edited by Michael A. Arthur and Robert E. Garrison. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 31 refs.; illus. incl. 1 table, chart, sketch map
Summary: Geochemical studies have been done on organic matter from biogenic sediments from Deep-Sea Drilling Project site 532, which is under the seaward edge of the Benguela upwelling system and has light-dark color cycles resulting from variations in sediment properties. Cyclical fluctuations in opal, organic carbon, and calcium carbonate accompany the color changes. Examination of early Pleistocene sediments taken at 10-cm intervals from section 532B-17-2 reveals that high carbonate concentrations coincide with lower organic carbon percentages. Carbon and nitrogen isotope contents of organic matter remain essentially constant through the color cycles. Geolipid contents show somewhat better retention of original character in darker sediments than in lighter portions of this section and reflect variations in the degree of preservation of organic matter. The origin of the light-dark cycles may be fluctuations in the Benguela Current caused by variations in the earth's obliquity.
Year of Publication: 1986
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 07 Marine Geology and Oceanography; 24 Surficial Geology, Quaternary Geology; Africa; Atlantic Ocean; C-13/C-12; Calcium carbonate; Carbon; Cenozoic; Continental margin; Currents; Cycles; Cyclic processes; DSDP Site 532; Deep Sea Drilling Project; Geochemistry; IPOD; Isotopes; Leg 75; Lower Pleistocene; Marine sedimentation; Marine sediments; Milankovitch theory; Namibia; Neogene; O-18/O-16; Ocean circulation; Ocean currents; Oceanography; Organic compounds; Organic materials; Oxygen; Paleo-oceanography; Paleocirculation; Paleoclimatology; Pleistocene; Pliocene; Quaternary; Sedimentation; Sediments; South Atlantic; Southern Africa; Southwest Atlantic; Stable isotopes; Stratigraphic boundary; Stratigraphy; Tertiary; Upper Pliocene; Upwelling; Walvis Ridge
Coordinates: S201500 S194500 E0110000 E0102000
Record ID: 1987037308
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