Frequency, magnitude and character of hyperthermal events at the onset of the Early Eocene Climatic Optimum

• DOI: 10.5194/cp-11-1313-2015
• Publication Date: 2015-10-07T11:27:52Z
• Authors: V. Lauretano; K. Littler; M. Polling; J. C. Zachos; L. J. Lourens
• Keywords: δ18O; Orbital forcing

Abstract. Recent studies have shown that the Early Eocene Climatic Optimum (EECO) was preceded by a series of short-lived global warming events, known as hyperthermals. Here we present high-resolution benthic stable carbon and oxygen isotope records from ODP Sites 1262 1263 (Walvis Ridge, SE Atlantic) between ~ 54 52 million years ago, tightly constraining character, timing, magnitude six prominent hyperthermal events. These which include Thermal Maximum (ETM) 2 3, are studied in relation to orbital forcing long-term trends. Our findings reveal an almost linear relationship δ13C δ18O for all these hyperthermals, indicating eccentricity-paced covariance deep-sea temperature changes extreme perturbations exogenic pool persisted during events towards onset EECO, accordance with previous observations Paleocene (PETM) ETM2. The H2 I2, second pulses "paired" ETM2-H2 I1-I2, deviates respect other We hypothesize this could relate relatively higher contribution isotopically heavier source carbon, such peat or permafrost, and/or climate feedbacks/local circulation. Finally, two sites show systematic offset on average 0.2 ‰ values shallower Site 1263, link slightly isotopic composition intermediate water mass reaching northeastern flank Walvis Ridge compared deeper northwestern at 1262.