HR: 0800h
AN: PP51D-0636    [Abstracts]
TI: Extending the High-Resolution Global Climate Record in Santa Barbara Basin: Developing a More Continuous Composite Section from Overlapping Cores
AU: * Behl, R J
EM: behl@csulb.edu
AF: California State University, Long Beach, Department of Geological Sciences, Long Beach, CA 90840 United States
AU: Kennett, J P
EM: kennett@geol.ucsb.edu
AF: University of California, Santa Barbara, Marine Science Institute and Department of Geological Sciences, Santa Barbara, CA 93106 United States
AU: Hill, T M
EM: tmhill @ucdavis.edu
AF: University of California, Davis, Department of Geology, Davis, CA 95616 United States
AU: Pak, D
EM: pak@geol.ucsb.edu
AF: University of California, Santa Barbara, Marine Science Institute and Department of Geological Sciences, Santa Barbara, CA 93106 United States
AU: Schimmelmann, A
EM: aschimme@indiana.edu
AF: Indiana University, Department of Geological Sciences, Bloomington, IN 47405 United States
AU: Cannariato, K G
EM: cannaria@usc.edu
AF: University of Southern California, Earth Science, Los Angeles, CA 90089 United States
AU: Nicholson, C
EM: nicholson@msi.ucsb.edu
AF: University of California, Santa Barbara, Marine Science Institute and Department of Geological Sciences, Santa Barbara, CA 93106 United States
AU: Sorlien, C C
EM: chris@crustal.ucsb.edu
AF: University of California, Santa Barbara, Marine Science Institute and Department of Geological Sciences, Santa Barbara, CA 93106 United States
AU: Hopkins, S E
EM: shopkins@umail.ucsb.edu
AF: University of California, Santa Barbara, Marine Science Institute and Department of Geological Sciences, Santa Barbara, CA 93106 United States
AU: Team, S
EM: nicholson@msi.ucsb.edu
AF: University of California, Santa Barbara, Marine Science Institute and Department of Geological Sciences, Santa Barbara, CA 93106 United States
AB: More than thirty ~2 to 5m-long piston cores were recovered from an eroded, breached anticline on the Mid-Channel Trend of the Santa Barbara Basin (SBB). Precision placement of cores enabled us to build several composite stratigraphic sections of overlapping cores. This was accomplished by continuous shipboard evaluation and feedback between pre-existing and concurrently acquired high-resolution seismic data and immediate sedimentologic core analysis to determine subsequent core locations. Overlap was confirmed by correlated stratigraphic patterns of alternating laminated vs. massive intervals, gray flood layers, spectrophotometric and MST density/porosity data. These cores were acquired to provide a semi-continuous, composite paleoceanographic record of the Quaternary SBB and the California Margin that extends beyond the fertile ODP Site 893 core, to possibly as old as 450 to 600 ka, an age previously unreachable by conventional methods. Most cores were mantled by glauconitic sand or a thin carbonate hardground encrusted with sessile organisms, including solitary corals. Underlying the condensed Holocene sand or hardground deposits are alternating layers of Pleistocene laminated and massive/bioturbated sediment with minor sand and sandy clay layers. The style, continuity, and variability of laminated fabric and the nature of bedding contacts are similar to that observed at ODP Site 893 where glacial episodes were associated with oxygenated, bioturbated sediment and interglacial and interstadial sediment were associated with dysoxic, laminated sediment. Laminated sediment comprises 38% of the hemipelagic deposits which is nearly identical with the ratio of laminated to massive sediment over the past 160 ky at Site 893. By extrapolation, despite accumulating in a mobile, deforming, active margin basin, the earlier Pleistocene deposits seem to record similar behavior to the last 160 ky recorded at ODP Site 893. In some intervals, gray layers are thicker and more abundant than at Site 893, perhaps suggesting more intense El Nino flood events. These initial data suggest that SBB will extend its usefulness as an ultra-high-resolution paleoceanographic record further into the past.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 1635 Oceans (1616, 3305, 4215, 4513)
DE: 3022 Marine sediments: processes and transport
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4901 Abrupt/rapid climate change (1605)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005