Host: Japan Association of Mineralogical Sciences
We studied about alteration textures of K-feldspar, petalite, Li-tourmaline and montebrasite-amblygonite, and discussed the alteration processes. K-feldspar was altered to cookeite, muscovite and quartz, or tosudite and beidellite-montmorillonite. Petalite was altered to cookeite and montmorillonite-beidellite. Li-tourmaline was altered to cookeite and muscovite. Montebrasite-amblygonite was altered to various phosphates and muscovite. With decreasing temperature, Li-chroritization, sericitization and smectitization had occured. In acidic condition, K-feldspar and petalite had breakdown, and cookeite formed with releasing K+. In acidic to neutral condition, Li-tourmaline had breakdown, and suffered sericitization. It is estimated that Li, B, P and F escape from pegmatite rock with reaction fluids.