Implications of excess 210Pb and 137Cs in sediment cores fromMikawa Bay, Japan
LU Xueqiang , MATSUMOTO Eiji
DOI:
Received April 29, 2008,Revised September 09, 2008, Accepted , Available online
Volume 21,2009,Pages 707-712
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Four sediment cores were collected from Mikawa Bay, Japan, and excess 210Pb and 137Cs were measured by gamma spectrometry.
Sedimentation rates for the four cores were determined by 210Pb method. The sedimentation rate range is 0.10–0.70 g/(cm2 year). The
bio-mixing depth for each core is less than 7.0 cm, and was determined by the excess 210Pb profiles as well. Therefore, the bioturbation
is slight. The 210Pb-derived dates coincided with the results from 137Cs geochronology. Acceleration in sedimentation rate due to
environmental alteration has been found in cores A2.5 and 05AS8, representing two depocenters due to their topography. Evidence of
the Tokai Flood in 2000 was found in core 05AS8 according to the profiles of both radioisotopes and trace metals.
