Late Eocene onset of the Proto-Antarctic Circumpolar Current

Type Article
Date 2019-07
Language English
Author(s) Sarkar Sudipta1, Basak Chandranath2, Frank Martin3, Berndt Christian3, Huuse Mads4, Badhani ShrayORCID5, Bialas Joerg3
Affiliation(s) 1 : Department of Earth and Climate Science, Indian Institute of Science Education and Research Pune, Pune, 411008, India
2 : Department of Geological Sciences, California State University, Bakersfield, CA, 93311, USA
3 : GEOMAR Helmholtz Centre for Ocean Research, Kiel, 24148, Germany
4 : School of Earth and Environmental Sciences, University of Manchester, Manchester, M13 9PL, UK
5 : IFREMER, Unité de Recherche Géosciences Marines, Centre de Bretagne, 1625 Route de Sainte-Anne, 29280, Plouzané, France
Source Scientific Reports (2045-2322) (Springer Science and Business Media LLC), 2019-07 , Vol. 9 , N. 1 , P. 10125 (10p.)
DOI 10.1038/s41598-019-46253-1
WOS© Times Cited 7

The formation of the Antarctic Circumpolar Current (ACC) is critical for the evolution of the global climate, but the timing of its onset is not well constrained. Here, we present new seismic evidence of widespread Late Eocene to Oligocene marine diagenetic chert in sedimentary drift deposits east of New Zealand indicating prolonged periods of blooms of siliceous microorganisms starting ~36 million years ago (Ma). These major blooms reflect the initiation of the arrival and upwelling of northern-sourced, nutrient-rich deep equatorial Pacific waters at the high latitudes of the South Pacific. We show that this change in circulation was linked to the initiation of a proto-ACC, which occurred ~6 Ma earlier than the currently estimated onset of the ACC at 30 Ma. We propose that the associated increased primary productivity and carbon burial facilitated atmospheric carbon dioxide reduction contributing to the expansion of Antarctic Ice Sheet at the Eocene-Oligocene Transition.

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