Crystalline clay minerals of the soils derived from recent volcanic ashes in Hokkaido, Japan

Abstract

In the previous study on clay minerals in the soils derived from recent volcanic ashes, it has been shown that expanding layer silicates with more or less interlayer-Al are found in large amounts among crystalline clay minerals, and that chlorite, illite and possibly kaolin minerals are found in small amounts (1). Montmori11onite shows a tendency to be dominant in the soils of the younger group and to be less Alinterlayered, However, vermiculite tends to increase, and both montmorillonite and vermiculite become more Al-interlayered in the soils of the older group. The purpose of the present report is to investigate 2: 1 type clay minerals, chiefly expanding layer silicates.