2003 Seattle Annual Meeting (November 2–5, 2003)

Paper No. 4
Presentation Time: 1:30 PM-5:30 PM


WARNKE, Detlef A.1, RICHTER, Carl2, FLORINDO, Fabio3, DAMUTH, John E.4, BALSAM, William L.5, STRAND, Kari6, RUIKKA, Mattina6, JUNTILA, Juho6, THEISSEN, Kevin7 and QUILTY, Patrick8, (1)Geological Sciences, California State Univ, Hayward, CA 94542, (2)Department of Geology, Univ of Louisiana, PO Box 44530, Lafayette, LA 70504, (3)Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna murata 605, Roma, 00143, Italy, (4)Department of Geology, Univ of Texas, 500 Yates Street, Room 107, Rlington, TX 76019, (5)Univ Texas - Arlington, Box 19049, Arlington, TX 76019-0049, (6)Thule Institute, Univ of Oulu, PO Box 7300, Linnanmaa, FIN-90014, Finland, (7)Geology and Environmental Sciences, Stanford Univ, Bldg. 320, Room 118, Stanford, CA 94305, (8)School of Earth Sciences, Univ of Tasmania, GPO Box 252-79, Hobart, 7050, Australia, dwarnke@csuhayward.edu

During ODP Leg 188 to Prydz Bay, East Antarctica, several of the shipboard scientists formed the High-Resolution Integrated Stratigraphy Committee (HiRISC). The committee was established in order to furnish an integrated data set from the Pliocene portion of Site 188-1165 as a contribution to the ongoing debate about Pliocene climate and climate evolution in Antarctica. The proxies that were determined in our various laboratories were the following: magnetostratigraphy and magnetic properties, grain-size distributions (granulometry), near-ultraviolet/visible/near-infrared (NUV/VIS/NIR) spectrophotometry, calcium carbonate content, characteristics of foraminifer, diatom, and radiolarian content, clay mineral composition, and stable isotopes. In addition to the HiRISC samples, other data sets contained in this report are subsets of much larger data sets.

Our data sets demonstrate a very dynamic East-Antarctic continental margin, with rapid depositional episodes alternating with erosional episodes and the formation of hiatuses. We see a pronounced change in most parameters at 34 mbsf, at about 3.4 to 3.5 Ma. For instance, brightness, ARM, IRM and ARM/IRM all change. Smectite decreases upcore whereas kaolinite increases. Maghemite decreases upcore, indicating either a change in source area/depositional mechanism, or a climatic deterioration. In any event, the dynamic behavior of the Antarctic margin, juxtaposed to the 'paralyzed landscapes' of the high-elevation interior, poses a challenge to paleoclimatologists and modelers.