Sea-level and salinity fluctuations during the Paleocene-Eocene thermal maximum in Arctic Spitsbergen

Abstract

Palaeoenvironmental manifestations of the Paleocene-Eocene thermal maximum (PETM; ~56Ma) are relatively well documented in low- to mid-latitude settings and at high southern latitudes, but no documented high northern latitude sites record the entire hyperthermal event. We present high-resolution multi-proxy records from a PETM succession on Spitsbergen in the high Arctic (palaeolatitude ~75°N). By comparing our results with those from Integrated Ocean Drilling Program Site 302-4A, we document regional palaeoenvironmental variations in the expression of the PETM, with evidence for major differences in basin-margin vegetation and water column oxygen depletion. Sedimentological, palynological and geochemical data demonstrate a pre-PETM sea level rise in Spitsbergen before the -4‰ δ13CTOC excursion, which culminated in maximum flooding during the peak of the event. The appearance of the dinoflagellate cyst Apectodinium before the onset of the carbon isotope excursion (CIE) corroborates that environmental change in the Arctic had begun prior to the CIE. Sedimentological and palynological evidence indicate that elevated terrestrial runoff resulted in water column stratification, providing further evidence for an intensification of the hydrological cycle during the PETM.