High-resolution deep-sea carbon and oxygen isotope records of Eocene Thermal Maximum 2 and H2

Abstract

Eocene Thermal Maximum 2 (ETM2) and H2 were two short-lived global warming events that occurred ~2 m.y. after the Paleocene-Eocene thermal maximum (PETM, ca. 56 Ma). We have generated benthic foraminiferal stable carbon and oxygen isotope records of four sites along a depth transect on Walvis Ridge (~3.5-1.5 km paleodepth, southeast Atlantic Ocean) and one site on Maud Rise (Weddell Sea) to constrain the pattern and magnitude of their carbon isotope excursions (CIEs) and deep-sea warming. At all sites, ETM2 is characterized by ~3 °C warming and a -1.4‰ CIE. The H2 event that occurred ~100 k.y. later is associated with ~2 °C warming and a -0.8‰ CIE. The magnitudes of the δ 13 C and δ 18 O excursions of both events are signifi cantly smaller than those during the PETM, but their coherent relation indicates that the δ 13 C change of the exogenic carbon pool was similarly related to warming during these events, despite the much more gradual and transitioned onset of ETM2 and H2.