HR: 0800h
AN: PP51B-0591    [Abstracts]
TI: Coast-to-Coast Record of the Paleocene-Eocene Thermal Maximum in Shallow Marine Environments
AU: * John, C M
EM: cjohn@pmc.ucsc.edu
AF: Earth Science Department, University of California, 1156 High Street, Santa Cruz, CA 95060 United States
AU: Bohaty, S M
EM: sbohaty@es.ucsc.edu
AF: Earth Science Department, University of California, 1156 High Street, Santa Cruz, CA 95060 United States
AU: Sluijs, A
EM: A.Sluijs@bio.uu.nl
AF: Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
AU: Brinkhuis, H
EM: h.Brinkhuis@bio.uu.nl
AF: Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
AU: Zachos, J C
EM: jzachos@pmc.ucsc.edu
AF: Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
AB: The Paleocene-Eocene Thermal Maximum (PETM) is characterized by rapid global warming, as much as 8° C, and a negative excursion in carbon isotopes (CIE). The magnitude of the CIE indicates rapid transfer of a large mass of carbon to the atmosphere. The rise in temperature associated with the addition of this greenhouse gas appears to have also altered global humidity and precipitation patterns, a feature often best expressed in near shore depositional facies. One goal of this study is to complement the deep-sea climate record with near shore, shallow-water records of regional climate change. We present sedimentologic, fossil, and geochemical data from three shallow-marine sections, one from the U.S. Pacific margin (Lodo formation, now exposed in the mountains of Central California), and two from the U.S. Atlantic Coastal Plain in New Jersey (drill sites at Bass River and Wilson Lake). Stable isotope analyses of foraminifera indicate that the magnitude of the isotopic excursion is globally similar to that in the deep-sea, although detail observations suggest that the excursion in bulk carbonate values in NJ sections is somewhat larger at the base of the CIE (Δδ¹³C=~4-6‰), particularly inshore, than what is typically measured in the deep sea (Δδ¹³C=~3‰). Carbonate dissolution may be truncating the excursion recorded in pelagic records. However, given the discrepancy between bulk and the foraminiferal data, we suspect that either diagenesis and/or vital effects and/or season-dependent intensification of the hydrological cycle and nutrient input may be contributing to more negative values in the bulk δ¹³C in shallow marine sections. We also find that δ¹³C of marine organic matter in each of these sections records the CIE, a particularly useful feature in sections containing few calcareous microfossils (due to dissolution or dilution). The magnitude of the excursion in these records is similar to the bulk carbonate record. Finally, clay mineral analysis indicate that kaolinite fluxes increased on both coasts at the onset of the CIE. Previous works have shown that on the U.S. East Coast this increase lasted for the duration of the CIE, and we document here that for the West Coast the increase was short-lived and corresponded to a single spike in the kaolinite to smectite ratio.
DE: 0428 Carbon cycling (4806)
DE: 0473 Paleoclimatology and paleoceanography (3344, 4900)
DE: 0790 Weathering (1625, 1886)
DE: 1041 Stable isotope geochemistry (0454, 4870)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005