上東 重石鑛床의 流體包有物 硏究

Fluid inclusion study of Sangdong tungsten deposits

Sangdong scheelite deposit is confirmed to have been formed by replacement of limestone beds by metasomatic mineralization. Mineralogical zonal distribution and filling temperatures are related with order of its formation and tungsten mineralization. The first formed garnet-pyroxene zone, left in the margins of the ore body, shows the highest filling temperature of fluid inclusions in pyroxene, averaging 420℃. The central part of the ore body, mainly composed of quartz-mica-scheelite, shows higher filling temperatures of fluid inclusions in quartz, than hornblende-quartz-scheelite zone surrounding the quartz-mica-scheelite zone, averaging 240℃. The distribution of highter filling temperatures above average temperature is applicable to the richest part of scheelite distribution. Generally scheelite shows higher filling temperature by about 20 to 100℃ than quartz in a given sample. The crystallization temperature of the main phase of scheelite deposition is 311℃ at the pressure of 230 to 500 bars at Sangdong area. Gas-rich inclusions in the pyroxene are homogenized into either gas or liquid phase or into both phases in a given crystal of the pyroxene, which suggests boiling at the formation of skarn.