Geoscience reports of Shimane University

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Geoscience reports of Shimane University 21
2002-12-27 発行

松江市に分布する"川津赤色粘土"について(予察)

“Kawatsu Red Clay”distributed in Matsue City,Southwest Japan(Preliminary Report)
Yamazaki, Chikako
Uno, Atsumi
Douzen, Kaori
Musashino, Makoto
File
Description
Red clay distributed in the northern Matsue City is a peculiar red(9 R 5/3-1 YR 4/3),and is characterized by higher Al_2O_3 contents(over 30 wt%)compared with normal soils.CIA(chemical index of alteration)values given by molar portions of Al/(Al+Na+Ca+K)x 100 are over 90,suggestive of significant weathering for the parent material.Although the color of this clay and CIA values are suggestive of dominant iron oxides or hydro-oxides.A possible parent material is alkaline basalt of the Matsue Formation,but chondrite-normalized REE patterns of the Kawastu red clay are characterized by relatively gentle inclination with negative Ce/Ce* and Eu/Eu* anomalies.The negative Ce* anomalie can result from explained REE alteration under reducing conditions.The Eu/Eu* negative anomalie can be explained by mixing of alkaline basalt and evolved material such as the Tertiary sediments which also occur in this district.
NCID
AA11455176