Paleoenvironmental Changes Associated with the PETM, Millville (ODP Leg 174AX), New Jersey Coastal Plain
Maria Makarova1, Kenneth G. Miller1, James D. Wright1, Yair Rosenthal2, Tali Babila2, and James V. Browning1
1Department of Earth and Planetary Sciences, Rutgers, The State University of New Jersey, 610 Taylor Road, Piscataway, NJ 08854-8066
2Institute of Marine and Coastal Sciences, Rutgers, The State University of New Jersey, 71 Dudley Road, New Brunswick, NJ 08901-8525
The Paleocene-Eocene Thermal Maximum (PETM) was an abrupt (<10 kyr) warming event, characterized by a global temperature increase of about 5°C. The PETM is recognized by the Carbon Isotope Excursion (CIE), represented by a ~2.5-4 ‰ decrease in δ13C values in open ocean coreholes (Kennett and Stott, 1991; Zachos et al., 2003). The New Jersey coastal plain contains thick (~15 m) sections recording the PETM. Kopp et al. (2009) proposed an enhanced hydrologic cycle to explain the widespread clay deposition on the mid-Atlantic continental shelf during the PETM. An increased flux of fresh water to the shelf would have lowered the salinities substantially. We tested this hypothesis by measuring changes in salinity in the PETM section in the Millville, New Jersey corehole (ODP Leg 174AX). We used two paleothermometers to constrain temperature changes associated with planktonic foraminiferal d18O variations, with the residual attributed to salinity changes. Using TEX86 and the Kim et al. (2010) calibration, we compute a 6°C warming across the CIE from 30 to 36°C; using TEX86 and the Taylor et al. (2013) calibration, we compute more of a warming (7.5°C), but cooler temperatures (22.5-30°C). Mg/Ca shows less of a warming. TEX86 shows a possible precursor warming at Wilson Lake, NJ (Sluijs et al., 2007); we compare TEX86 at Wilson Lake and Millville and conclude that the precursor warming may be spurious. Use of the Taylor et al. (2013) calibration yields salinity estimates and a ~2 psu salinity decrease associated with the CIE.
AAPG Search and Discovery Article #90182©2013 AAPG/SEG Student Expo, Houston, Texas, September 16-17, 2013