Boundary scavenging at the East Atlantic margin does not negate use of 231Pa/230Th to trace Atlantic overturning
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.
AWI Organizations > Geosciences > Marine Geochemistry
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 3: Lessons from the Past > WP 3.3: Proxy Development and Innovation: the Baseline for Progress in Paleoclimate Research