Drury, AJ;
Westerhold, T;
Frederichs, T;
Tian, J;
Wilkens, R;
Channell, JET;
Evans, H;
... Roehl, U; + view all
(2017)
Late Miocene climate and time scale reconciliation: Accurate orbital calibration from a deep-sea perspective.
Earth and Planetary Science Letters
, 475
pp. 254-266.
10.1016/j.epsl.2017.07.038.
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Abstract
Accurate age control of the late Tortonian to early Messinian (8.3–6.0 Ma) is essential to ascertain the origin of benthic foraminiferal δ18 trends and the late Miocene carbon isotope shift (LMCIS), and to examine temporal relationships between the deep-sea, terrasphere and cryosphere. The current Tortonian–Messinian Geological Time Scale (GTS2012) is based on astronomically calibrated Mediterranean sections; however, no comparable non-Mediterranean stratigraphies exist for 8–6 Ma suitable for testing the GTS2012. Here, we present the first high-resolution, astronomically tuned benthic stable isotope stratigraphy (1.5 kyr resolution) and magnetostratigraphy from a single deep-sea location (IODP Site U1337, equatorial Pacific Ocean), which provides unprecedented insight into climate evolution from 8.3–6.0 Ma. The astronomically calibrated magnetostratigraphy provides robust ages, which differ by 2–50 kyr relative to the GTS2012 for polarity Chrons C3An.1n to C4r.1r, and eliminates the exceptionally high South Atlantic spreading rates based on the GTS2012 during Chron C3Bn. We show that the LMCIS was globally synchronous within 2 kyr, and provide astronomically calibrated ages anchored to the GPTS for its onset (7.537 Ma; 50% from base Chron C4n.1n) and termination (6.727 Ma; 11% from base Chron C3An.2n), confirming that the terrestrial C3:C4 shift could not have driven the LMCIS. The benthic records show that the transition into the 41-kyr world, when obliquity strongly influenced climate variability, already occurred at 7.7 Ma and further strengthened at 6.4 Ma. Previously unseen, distinctive, asymmetric saw-tooth patterns in benthic δ18 imply that high-latitude forcing played an important role in late Miocene climate dynamics from 7.7–6.9 Ma. This new integrated deep-sea stratigraphy from Site U1337 can act as a new stable isotope and magnetic polarity reference section for the 8.3–6.0 Ma interval.
| Type: | Article |
|---|---|
| Title: | Late Miocene climate and time scale reconciliation: Accurate orbital calibration from a deep-sea perspective |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.epsl.2017.07.038 |
| Publisher version: | https://doi.org/10.1016/j.epsl.2017.07.038 |
| Language: | English |
| Additional information: | This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
| Keywords: | late Miocene, palaeoclimate, stable isotope stratigraphy, astrochronology, magnetostratigraphy, geological time scale |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10076972 |
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