Earth and Atmospheric Sciences, Department of

 

Document Type

Article

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.

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