Does sedimentary ²³¹Pa/²³⁰Th from the Bermuda Rise monitor past Atlantic Meridional Overturning Circulation?

Authors

Jörg Lippold, University of Heidelberg
Jens Grützner, University of Bremen
Diane Winter, University of Nebraska - Lincoln
Yann Lahaye, University of Frankfurt
Augusto Mangini, University of Heidelberg
Marcus Christl, Institute of Particle Physics

Date of this Version

2009

Citation

Lippold, J., J. Gru¨ tzner, D. Winter, Y. Lahaye, A. Mangini, and M. Christl (2009), Does sedimentary 231Pa/230Th from the Bermuda Rise monitor past Atlantic Meridional Overturning Circulation?, Geophys. Res. Lett., 36, L12601, doi:10.1029/2009GL038068.

Comments

Copyright 2009 by the American Geophysical Union. Used by permission.

Abstract

Ocean circulation may have undergone reductions and reinvigorations in the past closely tied to regional climate changes. Measurements of ²³¹Pa/²³⁰Th ratios in a sediment core from the Bermuda Rise have been interpreted as evidence that the Atlantic Meridional Overturning Circulation (AMOC) was weakened or completely eliminated during a period of catastrophic iceberg discharges (Heinrich-Event 1, H1). Here we present new data from the Bermuda Rise that show further ²³¹Pa/²³⁰Th peaks during Heinrich-2 (H2) and Heinrich-3 (H3). Additionally, a tight correlation between diatom abundances (biogenic silica) and ²³¹Pa/²³⁰Th is discovered in this core. Our results redirect the interpretation of ²³¹Pa/²³⁰Th from the Bermuda Rise as a proxy for ocean circulation towards a proxy that reacts highly sensitive to changes of particle composition and water mass properties.