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Enhanced Mediterranean water cycle explains increased humidity during MIS 3 in North Africa

Rogerson, Mike; Dublyansky, Yuri; Hoffman, Dirk L.; Luetscher, Marc; Töchterle, Paul; Spötl, Christoph

Authors

Yuri Dublyansky

Dirk L. Hoffman

Marc Luetscher

Paul Töchterle

Christoph Spötl

Abstract

We report a new fluid inclusion dataset from Northeast Libyan speleothem SC-06-01, which is the largest speleothem fluid inclusion dataset for North Africa to date. The stalagmite was sampled in Susah cave, a low altitude coastal site, in Cyrenaica, on the northern slope of the Jebel Al-Akhdar. Speleothem fluid inclusions from latest Marine Isotope Stage (MIS) 4 and throughout MIS 3 (~67 to ~30 ka BP) confirm the hypothesis that past humid periods in this region reflect westerly rainfall advected through the Atlantic storm track. However, most of this moisture was sourced from the Western Mediterranean, with little direct admixture of water evaporated from the Atlantic. Moreover, we identify a second moisture source likely associated with enhanced convective rainfall within the Eastern Mediterranean. The relative importance of the western and eastern moisture sources seems to differ between the humid phases recorded in SC-06-01. During humid phases forced by precession, fluid inclusions record compositions consistent with both sources, but the 52.5 – 50.5 ka interval forced by obliquity reveals only a western source. This is a key result, showing that although the amount of atmospheric moisture advections changes, the structure of the atmospheric circulation over the Mediterranean does not fundamentally change during orbital cycles. Consequently, an arid belt must have been retained between the Intertropical Convergence Zone and the mid-latitude winter storm corridor during MIS 3 pluvials.

Journal Article Type Article
Publication Date Sep 16, 2019
Print ISSN 1814-9324
Publisher European Geosciences Union
Peer Reviewed Peer Reviewed
Volume 15
Pages 1757–1769
Institution Citation Rogerson, M., Dublyansky, Y., Hoffman, D. L., Luetscher, M., Töchterle, P., & Spötl, C. (2019). Enhanced Mediterranean water cycle explains increased humidity during MIS 3 in North Africa. Climate of the Past, 15, 1757–1769. https://doi.org/10.5194/cp-2018-134
DOI https://doi.org/10.5194/cp-2018-134
Publisher URL https://www.clim-past.net/15/1757/2019/cp-15-1757-2019-discussion.html

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Copyright Statement
© Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.




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