Study on Fluid Inclusion and Genetic Modelling of Pegmatites at the Maewol Feldspar Mine

매월장석광산(梅月長石鑛山)의 페그마타이트내(內) 유체포유물(流體包有物)과 그 성인(成因)에 관한 모델 연구

Maewol Feldspar Mine produces feldspar ore from pegmatites. K-Rb Age of muscovite is 137.7Ma. Fluid inclusions in quartz crystal of the pegmatite show bimodal distribution of homogenization temperatures. The high homogenization temperatures range from 290 to $302^{\circ}C$ while low homogenization temperatures range from 157 to $195^{\circ}C$. Three phases liquid $CO_2$ bearing inclusions indicate $CO_2$ gases were abundantly mixed with granitic melt until the pegmatic magma melt cooled to $290^{\circ}C$. Low density of the magmatic melt relative to the same volume of granitic magma is due to mixture of volatiles(mainly $CO_2$ gases) with the melt and larger space and slow cooling allowed to grow crystals of the pegmatic magma.