Characteristics and Significance of Magmatic-Hydrothermal Transition in Jiama(Gyama) Monzonite Granite-porphyry, Tibet
西藏甲玛铜多金属矿二长花岗斑岩岩浆-热液过渡特征及成矿意义

Based on basic geological data,this paper summed up the characteristics and metallogenesis of the magmatic-hydrothermal transition in the Jiama(Gyama) monzonite granite-porphyry with the help of the electron microprobe analytical data and rock geochemical data in the aspects of petrology,petrography and geochemistry.The characteristics of the magmatic-hydrothermal transition in the Jiama(Gyama) monzonite granite-porphyry is manifested as tourmalinization-sodium/calcium silicate,like pegmatite-aplite shell(pulse),"adularia-habit" K-feldspar crystals,myrmekite,miarolitic cavities,while the geochemical characteristics are expressed as the growth and decrease of Na/K and the fluctuatation of the volatiles with the separation of the ore-forming materials such as Cu,Mo,Au.The development of the magmatic-hydrothermal transition can be divided into liquid immiscibility and volatile-liquid fractionation,the former dominated the mineral fractionation in the later magma,while the latter controlled the formation of ore solution and ore-forming hydrothermal fluids,forming disseminated mineralization and stockwork mineralization respectively.