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Extension of 239+240Pu sediment geochronology to coarse-grained marine sediments

Continental Shelf Research

By:
, ,
DOI: 10.1016/j.csr.2012.01.016

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Abstract

Sediment geochronology of coastal sedimentary environments dominated by sand has been extremely limited because concentrations of natural and bomb-fallout radionuclides are often below the limit of measurement using standard techniques. ICP-MS analyses of 239+240Pu from two sites representative of traditionally challenging (i.e., low concentration) environments provide a "proof of concept" and demonstrate a new application for bomb-fallout radiotracers in the study of sandy shelf-seabed dynamics. A kasten core from the New Zealand shelf in the Southern Hemisphere (low fallout), and a vibracore from the sandy nearshore of North Carolina (low particle surface area) both reveal measurable 239+240Pu activities at depth. In the case of the New Zealand site, independently verified steady-state sedimentation results in a 239+240Pu profile that mimics the expected atmospheric fallout. The depth profile of 239+240Pu in the North Carolina core is more uniform, indicating significant sediment resuspension, which would be expected in this energetic nearshore environment. This study, for the first time, demonstrates the utility of 239+240Pu in the study of sandy environments, significantly extending the application of bomb-fallout isotopes to coarse-grained sediments, which compose the majority of nearshore regions.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Extension of 239+240Pu sediment geochronology to coarse-grained marine sediments
Series title:
Continental Shelf Research
DOI:
10.1016/j.csr.2012.01.016
Volume
36
Issue:
15
Year Published:
2012
Language:
English
Publisher:
Elsevier
Publisher location:
Amsterdam, Netherlands
Contributing office(s):
St. Petersburg Coastal and Marine Science Center
Description:
6 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Continental Shelf Research
First page:
83
Last page:
88