Testing the extraction of past seawater Nd isotopic composition from North Atlantic deep sea sediments and foraminifera

Elmore, A. C. and Piotrowski, A. M. and Wright, J. D. and Scrivner, A. E. (2011) Testing the extraction of past seawater Nd isotopic composition from North Atlantic deep sea sediments and foraminifera. Geochemistry Geophysics Geosystems - GCubed, 12. 13 PP.. DOI 10.1029/2011GC003741

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Abstract

Neodymium isotopes provide a paleoceanographic proxy for past deep water circulation and local weathering changes and have been measured on various authigenic marine sediment components, including fish teeth, ferromanganese oxides extracted by acid‐reductive leaching, cleaned foraminifera, and foraminifera with Fe‐Mn oxide coatings. Here we compare Nd isotopic measurements obtained from ferromanganese oxides leached from bulk sediments and planktonic foraminifera, as well as from oxidatively‐reductively cleaned foraminiferal shells fromsediment cores in the North Atlantic. Sedimentary volcanic ash contributes a significant fraction of the Nd when the ferro‐manganese (Fe‐Mn) oxide coatings are leached from bulk sediments. Reductive leachates of marine sediments from North Atlantic core tops near Iceland, or directly downstream from Iceland‐Scotland Overflow Waters, record "Nd values that are significantly higher than seawater, indicating that volcanic material is easily leached by acid‐reductive methods. The "Nd values from sites more distal to Iceland are similar to modern seawater values, showing little contamination from Iceland‐derived volcanogenic material. In all comparisons, core top planktonic foraminifera "Nd values more closely approximate modern deep seawater than the bulk sediment reductive leached value suggesting that the foraminifera provide a route toward quantifying the Nd isotopic signature of deep North Atlantic water masses.

Item Type: Article
Uncontrolled Keywords: 2011AREP; IA63;
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Geochemistry Geophysics Geosystems - GCubed
Volume: 12
Page Range: 13 PP.
Identification Number: 10.1029/2011GC003741
Depositing User: Sarah Humbert
Date Deposited: 07 Oct 2011 17:04
Last Modified: 23 Jul 2013 10:02
URI: http://eprints.esc.cam.ac.uk/id/eprint/2192

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