O'CONNELL, SUZANNE, Wesleyan University, Middletown, CT; and MARK CHANDLER, Goddard Institute for Space Studies, New York, NY

ABSTRACT: Modeling the Paleocene/Eocene Boundary with the Goddard Institute for Space Studies (GISS), General Circulation Model (GCM)

General Circulaton Models (GCM) allow earth scientists to make quantitative global assessments of climate change. Paleoclimates provide the only testable climate change scenario. We have modeled the late Plaeocene (Thanetian) with the Goddard Institute for Space Studies (GISS) General Circulation Model (GCM). This interval was investigated because it was a warm period of very rapid change in both the climate and the carbon budget and may offer insights into changes taking place on earth today.

The Thanetian was warm, with the largest temperature increases (isotope{18}O), developing in the polar regions and relatively little temperature change in the tropics. During this same period delta{13}C shows one of the largest negative shifts in the Cenozoic (Shackleton et al., 1984). These isotopic changes are recorded in both planktonic and benthic organisms, and for a brief period, suggest warmer bottom than surface water (Kennett and Stott, 1990). Benthic foraminifers underwent the largest Cenozoic extinction (Thomas, 1990), and, like today, the late Paleocene experienced a rapid sea level rise.

The relationships between these changes and climate is unclear, but many hypotheses exist. For example, the lack of veritcal mixing has been attributed to warm, saline deep-water produced at mid-latitudes (Kennett and Stott, 1990). Although we can't model ocean salinity changes directly, we investigated changes in mid-latitude precipitation-evaporation, which are critical if such a change is plausible. These and other results of the model run will be presented.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.