S2: Water Rock Interaction (Special Session)

[S2-02] Weathering and alteration experiments of volcanic ash and pumice in an oxidative environment

*Nagisa Okabe², Hiroshi Isobe¹ (1. Kumamoto Univ., 2. Kumamoto Univ., Grad. Sch. Sci. Tech)

Keywords:clay mineral, volcanic ash, pumice, landslide

Oxidative hydrothermal alteration experiments were carried out on volcanic ash and pumice to represent initial weathering process on terrestrial surface. Oxidative condition is controlled by MnO2-Mn2O3 buffer in pressure vessels. Hydrous smectite occur in the run product from the volcanic ash on 200C, 120days. Volcanic ash may be more vulnerable than pumice in low pH conditions.