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

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doi: 10.5194/cp-11-1313-2015
Author(s): Lauretano, V.; Littler, K.; Polling, M.; Zachos, J. C.; Lourens, L. J.
Author Affiliation(s): Primary:
Utrecht University, Department of Earth Sciences, Utrecht, Netherlands
Other:
University of California Santa Cruz, United States
Volume Title: Climate of the Past
Source: Climate of the Past, 11(10), p.1313-1324. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. 53 refs.; illus., incl. 2 tables, sketch map
Summary: 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 and 1263 (Walvis Ridge, SE Atlantic) between ∼ 54 and ∼ 52 million years ago, tightly constraining the character, timing, and magnitude of six prominent hyperthermal events. These events, which include Eocene Thermal Maximum (ETM) 2 and 3, are studied in relation to orbital forcing and long-term trends. Our findings reveal an almost linear relationship between δ13C and δ18O for all these hyperthermals, indicating that the eccentricity-paced covariance between deep-sea temperature changes and extreme perturbations in the exogenic carbon pool persisted during these events towards the onset of the EECO, in accordance with previous observations for the Paleocene Eocene Thermal Maximum (PETM) and ETM2. The covariance of δ13C and δ18O during H2 and I2, which are the second pulses of the "paired" hyperthermal events ETM2-H2 and I1-I2, deviates with respect to the other events. We hypothesize that this could relate to a relatively higher contribution of an isotopically heavier source of carbon, such as peat or permafrost, and/or to climate feedbacks/local changes in circulation. Finally, the δ18O records of the two sites show a systematic offset with on average 0.2 per mil heavier values for the shallower Site 1263, which we link to a slightly heavier isotopic composition of the intermediate water mass reaching the northeastern flank of the Walvis Ridge compared to that of the deeper northwestern water mass at Site 1262.
Year of Publication: 2015
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Blake Nose; Blake Plateau; C-13/C-12; Carbon; Cenozoic; Chronology; Climate change; Climate forcing; Covariance analysis; Cycles; DSDP Site 550; DSDP Site 577; Deep Sea Drilling Project; Deep-sea environment; Early Eocene Climatic Optimum; Eccentricity; Eocene; IPOD; Isotope ratios; Isotopes; Leg 113; Leg 171B; Leg 208; Leg 80; Leg 86; Lower Eocene; Marine environment; North Atlantic; O-18/O-16; ODP Site 1051; ODP Site 1262; ODP Site 1263; ODP Site 690; Ocean Drilling Program; Orbital forcing; Oxygen; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleogene; Paleotemperature; Reconstruction; Relative age; South Atlantic; Stable isotopes; Statistical analysis; Tertiary; Transient phenomena; Walvis Ridge
Coordinates: S290000 S270000 E0030000 E0013000
Record ID: 2016034233
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Copernicus Gesellschaft, Katlenburg-Lindau, Germany