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32Si Dating of Marine Sediments from Bangladesh

Published online by Cambridge University Press:  18 July 2016

U Morgenstern ,
M A Geyh ,
H R Kudrass ,
R G Ditchburn  and
I J Graham
U Morgenstern*
Affiliation:
Institute of Geological & Nuclear Sciences (GNS), PO Box 30-368, Lower Hutt, New Zealand
M A Geyh
Affiliation:
Institute for Joint Geoscientific Research (GGA); Stilleweg 2; 30655 Hannover, Germany
H R Kudrass
Affiliation:
Federal Institute for Geosciences and Natural Resources (BGR), Germany
R G Ditchburn
Affiliation:
Institute of Geological & Nuclear Sciences (GNS), PO Box 30-368, Lower Hutt, New Zealand
I J Graham
Affiliation:
Institute of Geological & Nuclear Sciences (GNS), PO Box 30-368, Lower Hutt, New Zealand
*
Corresponding author. Email: u.morgenstern@gns.cri.nz.
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Abstract

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Appropriate dating tools are essential for paleoenvironmental studies. Cosmogenic 32Si with a half-life of about 140 years is ideally suited to cover the dating range 30–1000 years. Here we have applied scintillation spectrometry for detection of natural 32Si to date marine shelf sediments. High detection efficiency, combined with stable background, allows for the detection of extremely low 32Si specific activities found in such sediments with counting rates below one count per hour. For a sediment core from the Ganges-Brahmaputra delta 32Si dating yields mean sedimentation rates of 0.7 ± 0.2 cm/yr for 50 to several hundred years BP and 3.1 ± 0.8 cm/yr for the past 50 years. The four-fold increase of the sedimentation rate over the past 50 years may reflect increased sediment loads in the rivers due to increasing human colonization within the rivers' drainage basins.

Type
II. Our ‘Wet’ Environment
Information
Radiocarbon , Volume 43 , Issue 2B: Proceedings of the 17th International Radiocarbon Conference (Part 2 of 3), Conference Editors: Israel Carmi, Elisabetta Boaretto , 2001 , pp. 909 - 916
Copyright
Copyright © 2001 by the Arizona Board of Regents on behalf of the University of Arizona 

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