三宅島2000年噴火火山灰試料の化学的および鉱物学的諸性質について

概要

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Several chemical and mineralogical properties of volcanic ash samples erupted from the crater of Miyake island in the year of 2000 is as follows: 1. Clay contents and CEC values were much higher than those of volcanic ash samples from Sakurajima island and Mt. Usu. And smectite is present as observed for the volcanic ash samples from Mt. Usu. Therefore, it is suggested that volcanic ash samples are likely to contain secondary ashes previously weathered in crater as its major origin. 2. Both pH (H_2O) and pH (KCl) showed that the reaction of the ash sample is strongly acidic. It might be caused by the addition of large amounts of SO_2 gas from crater. 3. High amounts of exchangeable Al exist, and Al is assumed to be derived from the primary mineral dissolution with the decrease in pH. Almost all of the Ca^<2+> existed as water-soluble, and is present as gypsum.
日本ペドロジー学会の論文
2002-06-30