福島県大越町付近における石灰岩土壌中の粘土鉱物について(第1報) : 土壌の母材並びにその風化

抄録

1. The materials were collected from the hilly mountain, composed of saccharoidal limestone which sometimes intercalates thin layers of biotite schist. 2. The minerals observed in the sand fractions were quartz, oligoclase, andesine, hydrobiotite, hornblende, hypersthene, black opaque minerals, pumice and volcanic glass. 3. The fact that large amounts of pumice were found in all layers indicated that a great part of the parent material was composed of volcanic ash. 4. From the mineralogical composition it was considered that the weathering products of the limestone, intercalating thin layers of biotite schist were covered by dacitic volcanic ash, and further these mixed by subsequent, transportation. Since then the materials were mixed materials were covered by andestic volcanic ash. 5. Though large amounts of the soil were derived from the volcanic materials, the soil condition was considered to have been controlled by the weathering of limestone. 6. From X-ray and thermal experiments it was distinct that hydrated halloysite and montmorillonite were formed in the pumice. Hydrated holloysite was much more abundant in the upper layers. Montmorillonite was an essential component in every pumice of all layers except in that of the upper.