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PALEOCEANOGRAPHY, VOL. 21, PA1017, doi:10.1029/2004PA001075, 2006

Sub-Milankovitch cycles in periplatform carbonates from the early Pliocene Great Bahama Bank

Lars Reuning

Leibniz-Institut für Meereswissenschaften, IFM-GEOMAR, Kiel, Germany


John J. G. Reijmer

Leibniz-Institut für Meereswissenschaften, IFM-GEOMAR, Kiel, Germany


Christian Betzler

Department of Earth Sciences, University of Hamburg, Hamburg, Germany


Axel Timmermann

Leibniz-Institut für Meereswissenschaften, IFM-GEOMAR, Kiel, Germany


Silke Steph

Leibniz-Institut für Meereswissenschaften, IFM-GEOMAR, Kiel, Germany


Abstract

High-resolution bulk sediment (magnetic susceptibility and aragonite content) and δ18O records from two different planktonic foraminifera species were analyzed in an early Pliocene core interval from the Straits of Florida (Ocean Drilling Program site 1006). The δ18O record of the shallow-dwelling foraminifera G. sacculifer and the aragonite content are dominated by sub-Milankovitch variability. In contrast, magnetic susceptibility and the δ18O record of the deeper-dwelling foraminifera G. menardii show precession cycles. The relationship between the aragonite and the paleoproxy data suggests that the export of sediment from the adjacent Great Bahama Bank was triggered directly by atmospheric processes rather than by sea level change. We propose a climate mechanism that bears similarities with the semiannual cycle component of eastern equatorial Pacific sea surface temperatures under present-day conditions.

Received 23 July 2004; accepted 30 November 2005; published 30 March 2006.

Keywords: sub-Milankovitch cycles; teleconnections; Bahamas; aragonite cycles; El Niño–like state; precession.

Index Terms: 3022 Marine Geology and Geophysics: Marine sediments: processes and transport; 3339 Atmospheric Processes: Ocean/atmosphere interactions (0312, 4504); 3344 Atmospheric Processes: Paleoclimatology (0473, 4900); 4934 Paleoceanography: Insolation forcing; 4946 Paleoceanography: Milankovitch theory.

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Citation: Reuning, L., J. J. G. Reijmer, C. Betzler, A. Timmermann, and S. Steph (2006), Sub-Milankovitch cycles in periplatform carbonates from the early Pliocene Great Bahama Bank, Paleoceanography, 21, PA1017, doi:10.1029/2004PA001075.