LATE PLEISTOCENE SEA LEVELS BASED ON SEQUENCES FROM THE NEW JERSEY CONTINENTAL SHELF

Upper Pleistocene sequences, preferentially preserved in the ancestral Hudson River incised valley,indicate two large (30 -50m) and abrupt (5-10ky) sea-level fluctuations between OIS 5 and OIS 2. High resolution seismic stratigraphy reveals two highstand systems tracts at ~-20m and ~-30m and two lowstands systems tracts at ~-60m and ~-75m. The highstands are correlated with OIS 3 at ~55ka and ~35ka, and the lowstands are correlated with OIS 3 at ~45ka and OIS 4 at ~70ka. Radiocarbon and amino acid racemization data and superposition with ties to nannofossil datums on the continental slope constrain these ages. Paleoclimatological indicators in OIS 3 sediments, such as coiling of planktonic foraminifera, low pollen indices, and boreal pelecypods, indicate sub-arctic conditions off New Jersey. Although numerous climatic ("Heinrich") events occurred during OIS 3 and 4, there are only two major sea-level fluctuations on the New Jersey shelf, agreeing with two coeval methane events in Antarctic ice cores. Polar ice sheet dynamics that signifcantly affected sea level were less frequent than the Heinrich events. Sea level during OIS 5a was near present levels on the U.S. Atlantic margin and elsewhere around the world. Calibration of the delta 18 oxygen isotope curve with the OIS 5a sea level gives good agreement with the OIS 3 and 4 sea levels determined on the New Jersey shelf. This calibration implies significant cooling of the world's oceans during the late Pleistocene glacial period. The late Pleistocene temperature effect on the oxygen isotope data could be applied to older isotope records to constrain older ancient sea levels.