Time scale controversy; accurate orbital calibration of the early Paleogene

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doi: 10.1029/2012GC004096
Author(s): Westerhold, Thomas; Röhl, Ursula; Laskar, Jacques
Author Affiliation(s): Primary:
University of Bremen, Center for Marine Environmental Sciences, Bremen, Germany
Other:
Observatoire de Paris, France
Volume Title: Geochemistry, Geophysics, Geosystems - G<sup>3</sup>
Source: Geochemistry, Geophysics, Geosystems - G>3`, 13(6). Publisher: American Geophysical Union and The Geochemical Society, United States. ISSN: 1525-2027
Note: In English. 97 refs.; illus., incl. 3 tables
Summary: Timing is crucial to understanding the causes and consequences of events in Earth history. The calibration of geological time relies heavily on the accuracy of radioisotopic and astronomical dating. Uncertainties in the computations of Earth's orbital parameters and in radioisotopic dating have hampered the construction of a reliable astronomically calibrated time scale beyond 40 Ma. Attempts to construct a robust astronomically tuned time scale for the early Paleogene by integrating radioisotopic and astronomical dating are only partially consistent. Here, using the new La2010 and La2011 orbital solutions, we present the first accurate astronomically calibrated time scale for the early Paleogene (47-65 Ma) uniquely based on astronomical tuning and thus independent of the radioisotopic determination of the Fish Canyon standard. Comparison with geological data confirms the stability of the new La2011 solution back to ∼54 Ma. Subsequent anchoring of floating chronologies to the La2011 solution using the very long eccentricity nodes provides an absolute age of 55.530 ± 0.05 Ma for the onset of the Paleocene/Eocene Thermal Maximum (PETM), 54.850 ± 0.05 Ma for the early Eocene ash -17, and 65.250 ± 0.06 Ma for the K/Pg boundary. The new astrochronology presented here indicates that the intercalibration and synchronization of U/Pb and 40Ar/39Ar radioisotopic geochronology is much more challenging than previously thought.
Year of Publication: 2012
Research Program: ODP Ocean Drilling Program
Key Words: 03 Geochronology; 12 Stratigraphy, Historical Geology and Paleoecology; Absolute age; Ar/Ar; Atlantic Ocean; C-13/C-12; Calibration; Carbon; Cenozoic; Climate forcing; Colorado; Dates; Demerara Rise; Equatorial Atlantic; Fish Canyon; Isotope ratios; Isotopes; Leg 207; Leg 208; Lower Paleogene; Marine sediments; North Atlantic; Northwest Atlantic; O-18/O-16; ODP Site 1258; ODP Site 1262; Ocean Drilling Program; Orbital forcing; Oxygen; Paleocene-Eocene Thermal Maximum; Paleogene; Sediments; South Atlantic; Stable isotopes; Tertiary; Time scales; U/Pb; United States; Walvis Ridge; West Atlantic
Coordinates: S271100 S271100 E0013500 E0013400
N092600 N092600 W0544400 W0544400
Record ID: 2013084864
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