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Title Transcription
タイセキブツ ノ ゲンソ ソセイ カラミタ サンイン チイキ ジンザイコ ノ カンキョウ ヘンカ
Title Alternative (English)
Changes of sedimentary environments from geochemical compositions of sediments from Lake Jinzai, San’in district, Japan
File
language
jpn
Author
Yokoi, Emi
Description
 Changes in the sedimentary environment of Lake Jinzai were examined using the geochemical compositions of sediments. The lake has an area of 1.35 km2 and has become shallower with time. It now has a depth of about 1.5 m on average. After construction of the Sashimi River canal connecting Lake Jinzai with the Japan Sea, the lake waters have changed from fresh water to a brackish environment. The canal is a drainage system built for protection against flooding in this plain area. The lake has a varied and unique fishery, and is especially known for production of scallops(Corbicula japonica) that are renowned for their excellent taste. Geochemical examination of cored samples revealed historical changes of the environment. Total sulfur contents show a significant negative spike about 50 years before present. This change was related to large-scale flooding on the Izumo plains. Above this horizon, concentrations of P2O5 and heavy metals gradually increase upwards(e.g. P2O5, from 0.12 to 0.17 wt%: Zn, from 109 to 209 ppm). This change may be associated with increasing land use for agriculture. Th/Sc ratios and U concentrations show provenance change in accordance with this deterioration of the water environment. This change may have resulted from dominant inflow of local material of intermediate composition.
Journal Title
島根大学地球資源環境学研究報告
Volume
27
Start Page
35
End Page
41
ISSN
13439774
Published Date
2008-12-25
NCID
AA11455176
Publisher
島根大学総合理工学部地球資源環境学教室
Publisher Aalternative
Department of Geoscience, Interdisciplinary Faculty of Science and Engineering, Shimane University
NII Type
Departmental Bulletin Paper
OAI-PMH Set
Interdisciplinary Graduate School of Science and Engineering
Remark
12-14,16+ / 1993+
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