Orbital pacing of Eocene climate during the middle Eocene climate optimum and the chron C19r event; missing link found in the tropical western Atlantic

Online Access: Get full text
doi: 10.1002/ggge.20293
Author(s): Westerhold, Thomas; Röhl, Ursula
Author Affiliation(s): Primary:
University of Bremen, MARUM-Center for Marine Environmental Sciences, Bremen, Germany
Volume Title: Geochemistry, Geophysics, Geosystems - G<sup>3</sup>
Source: Geochemistry, Geophysics, Geosystems - G>3`, 14(11), p.4811-4825. Publisher: American Geophysical Union and The Geochemical Society, United States. ISSN: 1525-2027
Note: In English. 84 refs.; illus., incl. 2 tables
Summary: A high-resolution stratigraphy is essential toward deciphering climate variability in detail and understanding causality arguments of events in earth history. Because the middle to late Eocene provides a perfect testing ground for carbon cycle models to reconstruct the transition from a hothouse to an icehouse world, an accurate time scale is needed to decode climate-driving mechanisms. Here we present new results from ODP Site 1260 (Leg 207) which covers a unique expanded middle Eocene section (magnetochrons C18r to C20r, late Lutetian to early Bartonian) of the tropical western Atlantic including the chron C19r transient hyperthermal event and the Middle Eocene Climate Optimum (MECO). To establish a detailed cyclostratigraphy we acquired iron intensity records by XRF scanning Site 1260 cores. We revise the shipboard composite section, establish a cyclostratigraphy and use the exceptional eccentricity modulated precession cycles for orbital tuning. The new astrochronology revises the age of magnetic polarity chrons C19n to C20n, validates the position of very long eccentricity minima at 40.2 and 43.0 Ma in the orbital solutions and extends the Astronomically Tuned Geological Timescale back to 44 Ma. For the first time the new data provide clear evidence for an orbital pacing of the chron C19r event and a likely involvement of the very long (2.4 myr) eccentricity cycle contributing to the evolution of the MECO. Abstract Copyright (2013). American Geophysical Union. All Rights Reserved.
Year of Publication: 2013
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Bartonian; Cenozoic; Climate change; Climate forcing; Cyclostratigraphy; Demerara Rise; Eocene; Equatorial Atlantic; Icehouse effect; Leg 207; Lutetian; Magnetostratigraphy; Middle Eocene; North Atlantic; Northwest Atlantic; ODP Site 1260; Ocean Drilling Program; Orbital forcing; Paleo-oceanography; Paleogene; Statistical analysis; Stratigraphy; Tertiary; Time series analysis; Variations; West Atlantic; X-ray analysis; X-ray fluorescence
Coordinates: N091600 N091600 W0543300 W0543300
Record ID: 2014034971
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom, Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union