南関東の累積性火山灰土の土壌微細形態学的解析(III) : 薄片中の粒子の解析  [in Japanese] A Micromorphological Study of Some Volcanic Soils (III) : Analysis of Particles with Large Thin Section  [in Japanese]

I aimed to clarify the micromorphological and mesomorphological character of soils of volcanic ash origin. The result of observation of characteristic particles with the large thin section was as follows. In reddish-brown particles, 2mm^2 or less dominated in all layer. Distribution pattern of reddish-brown particles of any layer was scatter and circular pattern. In black particles, 1.5mm^2 or less were majority and 1.0mm^2 or less were majority in gray particles. Distribution pattern of black and gray particles were scatter and circular pattern. Layers could divided roughly into 3 groups by characteristic particles. The first group mainly consists of reddish-brown were IIa, IIb, III and IV (upper). The second group were IV (lower), V, VI, VII and IX. The third group was XIII. In addition, lst group could subdivide to Ha and IIb, III and IV (upper), 2nd group could subdivide to IV (lower), V, VI and VII, IX further with black and gray particle.