EXTREME WARMING OF THE MID-LATITUDE COASTAL OCEAN DURING THE PALEOCENE-EOCENE THERMAL MAXIMUM: INFERENCES FROM TEX86 AND ISOTOPE DATA

Changes in sea surface temperature (SST) during the Paleocene-Eocene Thermal Maximum (PETM) have been estimated primarily from oxygen isotope and Mg/Ca records generated from analyses of deep-sea cores. These records indicate warming of as much as 5 to 10°C between the tropics and poles. Here we present a record of sea surface temperature and salinity change across the P-E boundary for a near-shore, shallow marine section recovered in a core located near Wilson Lake, NJ. Carbon isotope and calcareous nannofossil records provide the primary chronostratigraphic constraints. The SST record is derived primarily from a new proxy of temperature TEX86, a measure of the concentration of cyclopentane rings in sedimentary membrane lipids derived from marine crenarchaeota. The TEX86 data indicate 8 to 9°C of warming, with peak temperatures in excess of 37°C, estimates which are consistent with constraints provided by oxygen isotope ratios of planktonic foraminifera. The rise in SST was accompanied by a significant increase in clay accumulation rates, and in the abundances of dinoflagellate Apectodinium indicating locally increased precipitation and runoff. Estimates of normal to higher salinity based on the oxygen isotopes, and the lack of evidence for strongly brackish conditions, however, suggests transition into a local climate regime characterized by a prolonged dry season and a short, but intense wet season.