Excess ²¹⁰Pb and ¹³⁷Cs concentrations, mass accumulation rates, and sedimentary processes on the Bering Sea continental shelf

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• 作者：Kazumasa Oguri^a ; ^{ogurik@jamstec.go.jp} ; Naomi Harada^b ; ^{haradan@jamstec.go.jp} ; Osamu Tadai^c ; ^{tadaio@mwj.co.jp}
• 关键词：Bering Sea ; Sediment ; Excess 210Pb concentration ; Mass accumulation rate
• 刊名：Deep Sea Research Part II ; Topical Studies in Oceanography
• 出版年：2012
• 期刊代码：20_09670645
• 类别：ear
• 出版时间：February-March, 2012
• 卷：61-64
• 期：Complete
• 页码：193-204
• 文件大小：1424 K

摘要

We used ²¹⁰Pb and ¹³⁷Cs concentrations in twelve cores from the continental shelf and slope of the Bering Sea to investigate recent mass accumulation rates in sediments and sedimentation processes. No decreases in exogenic ²¹⁰Pb concentrations with depth were observed in sediments from the shallow shelf area, suggesting that there has been considerable mixing of the sediments there. However, we calculated mass accumulation rates from ²¹⁰Pb_ex profiles for several cores collected from the outer shelf and the slope. Mass accumulation rates in the sediments from these cores ranged from 0.11 to 0.44 g cm^鈭? y^鈭?. For the cores with a mixed surface layer, we showed that sediments that accumulated over the last 50-78 years were mixed. The ²¹⁰Pb_ex inventories in the sediment cores suggested deposition of ²¹⁰Pb particles was focused in the slope area. ¹³⁷Cs was observed in the sediments collected from the northern to western shelf areas. The ¹³⁷Cs inventories showed higher values in the shelf area, which suggests that fine-grained particles from the Yukon River have contributed to sedimentation there.