Astronomical calibration of the geological timescale; closing the middle Eocene gap

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doi: 10.5194/cp-11-1181-2015
Author(s): Westerhold, T.; Röhl, U.; Frederichs, T.; Bohaty, S. M.; Zachos, J. C.
Author Affiliation(s): Primary:
University of Bremen, Center for Marine Environmental Sciences, Bremen, Germany
University of Southampton, United Kingdom
University of California at Santa Cruz, United States
Volume Title: Climate of the Past
Source: Climate of the Past, 11(9), p.1181-1195. Publisher: Copernicus, Katlenburg-Lindau, International. ISSN: 1814-9324
Note: In English. 77 refs.; illus., incl. 3 tables, sketch map
Summary: To explore cause and consequences of past climate change, very accurate age models such as those provided by the astronomical timescale (ATS) are needed. Beyond 40 million years the accuracy of the ATS critically depends on the correctness of orbital models and radioisotopic dating techniques. Discrepancies in the age dating of sedimentary successions and the lack of suitable records spanning the middle Eocene have prevented development of a continuous astronomically calibrated geological timescale for the entire Cenozoic Era. We now solve this problem by constructing an independent astrochronological stratigraphy based on Earth's stable 405 kyr eccentricity cycle between 41 and 48 million years ago (Ma) with new data from deep-sea sedimentary sequences in the South Atlantic Ocean. This new link completes the Paleogene astronomical timescale and confirms the intercalibration of radioisotopic and astronomical dating methods back through the Paleocene-Eocene Thermal Maximum (PETM, 55.930 Ma) and the Cretaceous-Paleogene boundary (66.022 Ma). Coupling of the Paleogene 405 kyr cyclostratigraphic frameworks across the middle Eocene further paves the way for extending the ATS into the Mesozoic.
Year of Publication: 2015
Research Program: ODP Ocean Drilling Program
Key Words: 03 Geochronology; 12 Stratigraphy, Historical Geology and Paleoecology; Absolute age; Accuracy; Atlantic Ocean; C-13/C-12; Calibration; Carbon; Cenozoic; Chronostratigraphy; Cycles; Cyclostratigraphy; Eccentricity; Eocene; Isotope ratios; Isotopes; Leg 114; Leg 207; Leg 208; Magnetostratigraphy; Middle Eocene; ODP Site 1258; ODP Site 1260; ODP Site 1263; ODP Site 702; Ocean Drilling Program; Paleocene-Eocene Thermal Maximum; Paleogene; Paleomagnetism; Reversals; South Atlantic; Stable isotopes; Statistical analysis; Stratigraphic gaps; Tertiary; Time scales; Time series analysis
Coordinates: S515905 S465245 E0075341 W0330558
S290000 S270000 E0030000 E0013000
Record ID: 2016044112
Copyright Information: GeoRef, Copyright 2020 American Geosciences Institute. Reference includes data from Copernicus Gesellschaft, Katlenburg-Lindau, Germany