The tin-bearing topaz-quartz porphyry, yangbin area, Taishun county, Ahejiang province- a fluid inclusion study

摘要

The tin-bearing topaz-quartz porphyry in the Yanbin area is subvolcanic in origin, derived from granitic residual magma through strong crystallization differentiation. The rock contains various types of inclusion (hydroxyl-melt, vapor-rich, halite-bearing multiphase, and lliquid-rich), which permits us to trace the evolutionary path of the fluid. It is suggested that immiscibility took place in a pulsating manner between melts and fluids during the rock-forming process with the homogeniation temperatures ranging from 580 deg.C to 180 deg.C and the salinities varying from low through high to low (5.1-10.5→6.9-21.4→30-48→16-22→2-10 in wt/100 NaCl). The hydroxyl-melt inclusions are considered as evidence of magma-hydrother- mal transition.