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Pre-Bomb Radiocarbon Variability Inferred from a Kenyan Coral Record

Published online by Cambridge University Press:  18 July 2016

Nancy S Grumet ,
Thomas P Guilderson  and
Robert B Dunbar
Nancy S Grumet
Affiliation:
Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 USA. Email: [email protected].
Thomas P Guilderson
Affiliation:
Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California 94551. Also at the Institute of Marine Sciences, University of California at Santa Cruz, Santa Cruz, California 65064 USA.
Robert B Dunbar
Affiliation:
Department of Geological and Environmental Sciences, Stanford University, Stanford, California 94305 USA
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Abstract

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We report results from AMS radiocarbon measurements (δ14C) in corals recovered off the coast of Kenya. Bimonthly samples which span the pre-bomb era average −51 (±3.7; n=43), when age and Suess effect are corrected, and over the time of interest (1946–1954) do not exhibit any discernible seasonality. Relative to regional pre-bomb δ14C values in the western Indian Ocean, our results indicate 14C enrichment off the coast of Kenya. Furthermore, the absence of a distinct subannual δ14C signal suggests that open and coastal upwelling is negligible off the coast of Kenya. Unlike pre-bomb values south of the equator near Seychelles and Madagascar, our pre-bomb value are enriched by more than 10. The enrichment of pre-bomb Kenyan δ14C values relative to sites around Mauritius, northern Madagascar and Seychelles, suggest that the influence of depleted δ14C water transported in the SEC is limited to regions south of 3 to 4°S.

Type
Articles
Information
Radiocarbon , Volume 44 , Issue 2 , 2002 , pp. 581 - 590
Copyright
Copyright © 2002 The Arizona Board of Regents on behalf of the University of Arizona 

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