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

verfasst von

Jörg Lippold, Stefan Mulitza, Gesine Mollenhauer, Stefan Weyer, David Heslop, Marcus Christl

Abstract

The ²³¹Pa/ 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 ²³¹Pa and ²³⁰Th in ocean water. Here we present ²³¹Pa/ ²³⁰Th down-core profiles from high particle flux areas off Namibia and Senegal covering the past ~35ka. The ²³¹Pa/ 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 ²³¹Pa/ 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 ~30ka the high productivity Eastern margin was not capable of importing and storing significant amounts of ²³¹Pa from the open Ocean. Consequently, the applicability of the ²³¹Pa/ ²³⁰Th proxy to reconstruct past ocean circulation is not hampered by this potentially additional ²³¹Pa sink.

Organisationseinheit(en)

Institut für Mineralogie
AG Geochemie

Externe Organisation(en)

Ruprecht-Karls-Universität Heidelberg
Universität Bremen
Goethe-Universität Frankfurt am Main
Australian National University
ETH Zürich

Typ

Artikel

Journal

Earth and Planetary Science Letters

Band

333-334

Seiten

317-331

Anzahl der Seiten

15

ISSN

0012-821X

Publikationsdatum

01.06.2012

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Geophysik, Geochemie und Petrologie, Erdkunde und Planetologie (sonstige), Astronomie und Planetologie

Ziele für nachhaltige Entwicklung

SDG 14 – Lebensraum Wasser

Elektronische Version(en)

https://doi.org/10.1016/j.epsl.2012.04.005 (Zugang: Unbekannt)