Boundary scavenging at the East Atlantic margin does not negate use of 231Pa/230Th to trace Atlantic overturning


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Gesine.Mollenhauer [ at ] awi.de

Abstract

The 231Pa/230Th methodisapromisingtooltoreconstructOceancirculationoverthepastGlacial– Interglacialcycle.However,marineparticlefluxmayconstraintheapplicabilityofthisratioasadirect quantitativeproxyforthestrengthofAtlanticMeridionalOverturningCirculation(AMOC)by influencingthefractionationbetweentheinsituproduced 231Pa and 230Th inoceanwater.Herewe present 231Pa/230Th down-coreprofilesfromhighparticlefluxareasoffNamibiaandSenegalcovering the past �35 ka.The 231Pa/230Th profilesatthesesitesshowverydifferentresponsestotemporal variationsofparticlefluxesandtochangesinwatermasses.Ourresultsshowthatsedimentary 231Pa/230Th intheEasternAtlanticmarginislinkedtoparticleflux,butcontrolledprimarilybythe mode oftheAMOC.Ourdatasuggestthatduringthepast �30 kathehighproductivityEasternmargin was notcapableofimportingandstoringsignificantamountsof 231Pa fromtheopenOcean. Consequently,theapplicabilityofthe 231Pa/230Th proxytoreconstructpastoceancirculationisnot hamperedbythispotentiallyadditional 231Pa sink.



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ISI/Scopus peer-reviewed
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Published
Eprint ID
32410
DOI 10.1016/j.epsl.2012.04.005

Cite as
Lippold, J. , Mulitza, S. , Mollenhauer, G. , Weyer, S. , Heslop, D. and Christl, M. (2012): Boundary scavenging at the East Atlantic margin does not negate use of 231Pa/230Th to trace Atlantic overturning , Earth and Planetary Science Letters, 333-33 , pp. 317-331 . doi: 10.1016/j.epsl.2012.04.005


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