Distance-dependence from volcano for Asian dust inclusions in Andosols: A key to control soil ability to retain radiocesium

Abstract Deposition of Asian dust, i.e. mica-bearing aeolian particles, throughout geological times has contributed greatly to the increased ability of soil to specifically retain radiocesium (137Cs), particularly in soils derived from mica-deficient parent materials. Allophanic Andosols, volcanic mica-deficient soils, in Japan were hypothesized to contain fewer micaceous minerals proximal to volcanoes due to the dilution of Asian dust by thicker volcanic ash depositions. To test this hypothesis, we collected soils from stratified horizons mainly composed of mafic volcanic ash at four sites near the volcanic crater of Mt. Aso, Japan. The profiles were in volcanic ash soil dominated by poorly ordered clay minerals, and classified as Allophanic Andosols. Radiocesium interception potential (RIP) and mineral content were determined on soil particles fractionated to