The seawater neodymium and lead isotope record of the final stages of Central American Seaway closure.

Osborne, Anne H. , Newkirk, Derrick R., Groeneveld, Jeroen, Martin, Ellen E., Tiedemann, Ralf and Frank, Martin (2014) The seawater neodymium and lead isotope record of the final stages of Central American Seaway closure. Open Access Paleoceanography, 29 (7). pp. 715-729. DOI 10.1002/2014PA002676.

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Supplementary data:

Abstract

Key Points:
Seawater Nd and Pb isotope records for the Pliocene Caribbean and EEP
Caribbean Nd isotope composition became more UNADW-like during the Pliocene
Short term changes support link between CAS closure and strength of AMOC

The shoaling and final closure of the Central American Seaway (CAS) resulted in a major change of the global ocean circulation and has been suggested as an essential driver for strengthening of Atlantic Meridional Overturning Circulation (AMOC). The exact timing of CAS closure is key to interpreting its importance. Here we present a reconstruction of deep and intermediate water Nd and Pb isotope compositions obtained from fossil fish teeth and the authigenic coatings of planktonic foraminifera in the eastern equatorial Pacific (ODP Site 1241) and the Caribbean (ODP Sites 998, 999 and 1000) covering the final stages of CAS closure between 5.6 and 2.2 Ma. The data for the Pacific site indicate no significant Atlantic/Caribbean influence over this entire period. The Caribbean sites show a continuous trend to less radiogenic Nd isotope compositions during the Pliocene, consistent with an enhancement of Upper North Atlantic Deep Water (UNADW) inflow and a strengthening of the AMOC. Superimposed onto this long-term trend, shorter-term changes of intermediate Caribbean Nd isotope signatures approached more UNADW-like values during intervals when published reconstructions of seawater salinity suggested complete closure of the CAS. The data imply that significant deep water exchange with the Pacific essentially stopped by 7 Ma and that shallow exchange, which still occurred at least periodically until approximately 2.5 Ma, may have been linked to the strength of the AMOC but did not have any direct effect on the intermediate and deep Caribbean Nd isotope signatures through mixing with Pacific waters.

Document Type: Article
Additional Information: WOS:000342506800002
Keywords: Pliocene; Panama; neodymium isotopes; AMOC; lead isotopes
Research affiliation: AWI
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-P-OZ Paleo-Oceanography
Kiel University
Refereed: Yes
Open Access Journal?: No
DOI etc.: 10.1002/2014PA002676
ISSN: 0883-8305
Projects: Laptev Sea System, Transdrift
Date Deposited: 27 Jun 2014 08:11
Last Modified: 10 May 2017 07:01
URI: http://oceanrep.geomar.de/id/eprint/24974

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