Eolian origin of the micaceous minerals in an ando soil from Kitakami, Japan

A fin-grained Ando soil rich in micaceous minerals and quartz developed on volcanic ashes in Kitakami, Iwate has been analysed for the K-Ar age parameter to determine" hether the micaceous minerals had an eolian. volcanic or pedogenic origin. K-Ar age is approximately 2,000 times greater than the age of the deposition of parent volcanic ashts. The measurement, coupled with the determination of the quartz oxygen isotopic abundance reported elsewhere enabled to demonstrate that the finegrained mica- and quartz-bearing phase of an Ando soil is not derived from local volcanic matenals and does not have an authigenic origin along with confirming the importance of eolian transport from Asian land masses. The eolian sediment influence on soil and sediment development is significant particularly in the highlands located along the Japanese central backbone range where heavy snowfall occurs.