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

authored by

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.

Organisation(s)

Institute of Mineralogy
Geochemistry

External Organisation(s)

Heidelberg University
University of Bremen
Goethe University Frankfurt
Australian National University
ETH Zurich

Type

Article

Journal

Earth and Planetary Science Letters

Volume

333-334

Pages

317-331

No. of pages

15

ISSN

0012-821X

Publication date

01.06.2012

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Geophysics, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Space and Planetary Science

Sustainable Development Goals

SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.1016/j.epsl.2012.04.005 (Access: Unknown)