Tada, Ryuji; Sato, Sohei; Irino, Tomohisa; Matsui, Hiroyuki; Kennett, James P. (2000): Millennial-scale compositional variations in late Quaternary sediments at Site 1017, Southern California. Texas A & M University, Ocean Drilling Program, College Station, TX, United States, In: Lyle, Mitchell, Koizumi, Itaru, Richter, Carl, Behl, Richard J., Boden, Per, Caulet, Jean-Pierre, Delaney, Margaret L., deMenocal, Peter, Desmet, Marc, Fornaciari, Eliana, Hayashida, Akira, Heider, Franz, Hood, Julie A., Hovan, Steven A., Janecek, Thomas R., Janik, Aleksandra G., Kennett, James P., Lund, David, Machain Castillo, Maria L., Maruyama, Toshiaki, Merrill, Russell B., Mossman, David J., Pike, Jennifer, Ravelo, A. Christina, Rozo Vera, Gloria A., Stax, Rainer, Tada, Ryuji, Thurow, Juergen W., Yamamoto, Masanobu, Nessler, Susan (editor), Miller, Christine M. (editor), Peters, Lorri L. (editor), Proceedings of the Ocean Drilling Program, scientific results, California margin; covering Leg 167 of the cruises of the drilling vessel JOIDES Resolution, Acapulco, Mexico, to San Francisco, California, sites 1010-1022, 20 April-16 June 1996, 167, 277-296, georefid:2000-080041

Abstract:
Intensification of North Pacific Intermediate Water during the Younger Dryas and stadials of the last glacial episode has been advocated by Kennett and his colleagues based on studies of ventilation history in Santa Barbara Basin. Because Santa Barbara Basin is a semi-isolated marginal basin, this hypothesis requires testing in sequences on the upper continental margin facing the open-ocean of the Pacific. Ocean Drilling Program Site 1017 is located on the upper slope of southern California off Point Conception close to the entrance of Santa Barbara Basin, an ideal location to test the hypothesis of late Quaternary switching in intermediate waters. We examined chemical and mineral composition, sedimentary structures, and grain size of hemipelagic sediments representing the last 80 k.y. at this site to detect changes in behavior of intermediate waters. We describe distinct compositional and textual variations that appear to reflect changes in grain size in response to flow velocity fluctuations of bottom waters. Qualitative estimates of changes in degree of pyritization indicate better ventilation of bottom water during intervals of stronger bottom-water flow. Comparison between variations in the sediment parameters and the planktonic delta (super 18) O record indicates intensified bottom-current activity during the Younger Dryas and stadials of marine isotope Stage 3. This result strongly supports the hypothesis of Kennett and his colleagues. Our investigation also suggests strong grain-size control on organic carbon content (and to less extent carbonate carbon content). This, in turn, suggests the possibility that organic carbon content of sediments, which is commonly used as an indicator of surface productivity, can be influenced by bottom currents.
Coverage:
West: -121.0625 East: -121.0625 North: 34.3205 South: 34.3205
Relations:
Expedition: 167
Site: 167-1017
Supplemental Information:
Includes appendices
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.2973/odp.proc.sr.167.222.2000 (c.f. for more detailed metadata)
Data download: application/pdf
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