Earth and Planetary Science Letters, June 1, 2012, Vol.333-334, p.317(15)
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.epsl.2012.04.005 Byline: Jorg Lippold (a), Stefan Mulitza (b), Gesine Mollenhauer (b), Stefan Weyer (c), David Heslop (d), Marcus Christl (e) Keywords: .sup.231Pa/.sup.230Th; AMOC; boundary scavenging; North Atlantic Deep Water; LGM; African margin Abstract: The.sup.231Pa/.sup.230Th method is a promising tool to reconstruct Ocean circulation over the past Glacial-Interglacial cycle. However, marine particle flux may constrain the applicability of this ratio as a direct quantitative proxy for the strength of Atlantic Meridional Overturning Circulation (AMOC) by influencing the fractionation between the in situ produced.sup.231Pa and.sup.230Th in ocean water. Here we present.sup.231Pa/.sup.230Th down-core profiles from high particle flux areas off Namibia and Senegal covering the past [approximately equal to]35ka. The.sup.231Pa/.sup.230Th profiles at these sites show very different responses to temporal variations of particle fluxes and to changes in water masses. Our results show that sedimentary.sup.231Pa/.sup.230Th in the Eastern Atlantic margin is linked to particle flux, but controlled primarily by the mode of the AMOC. Our data suggest that during the past [approximately equal to]30ka the high productivity Eastern margin was not capable of importing and storing significant amounts of.sup.231Pa from the open Ocean. Consequently, the applicability of the.sup.231Pa/.sup.230Th proxy to reconstruct past ocean circulation is not hampered by this potentially additional.sup.231Pa sink. Author Affiliation: (a) University of Heidelberg, Institute of Environmental Physics, 69120 Heidelberg, Germany (b) MARUM, University of Bremen, Institute of Geoscience, 28359 Bremen, Germany (c) University of Frankfurt, Institute of Geoscience, 60438 Frankfurt, Germany (d) Australian National University, Research School of Earth Sciences, Canberra ACT 0200, Australia (e) ETH Zurich, Laboratory of Ion Beam Physics, 8093 Zurich, Switzerland Article History: Received 17 June 2011; Revised 29 March 2012; Accepted 6 April 2012 Article Note: (miscellaneous) Editor: G. Henderson
Ocean Circulation ; Thermohaline Circulation
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