Dynamic changes of composition of mineral filling veins in metamorphic rocks

Abstract

Several types of mineral filling veins were observed in metamorphic rocks, which provides valuable information on solution chemistry and transport phenomena of geolfuils. Accreational sediments (Shimanto Belt), metamorphics in subduction zone (Sanbagawa metamorphic rocks) and high grade metamorphic rocks in collision zone (Hidaka metamorphic Belts) were investigated. Based on field occurrence, mineral assemblages, mineral texture, and mineral composition of mineral filling vein, formation mechanism of geofluids, especially velocity of fluid ascent through rock fractures, were revealed. Using activity diagram of fluids, small variation of pressure affected stability of potassium feldspar. Ascending flow velocity was estimated on the basis of texture and grain size distribution of quartz within mineral filling vein.