東明鑛山의 스카른型 灰重石 鑛床의 成因

On the Genesis of Skarn-type Scheelite Deposits at the Dongmyoung mine

The skarn type tungsten deposits are developed in the contact aureole of Jurassic biotite-hornblende granodiorite and limestone beds. The latter can be divided into the Great Limestone Series of Joseon System and Gabsan Formation which is correlative to the Hongjeom Series of Pyeongahn System. The skarns are impregnated in the limestone, sandstone, schist and granodiorite, and showing zonal distribution. The five skarn zones are from fresh limestone inwards to wollastonite-skarn, clinopyroxene-skarn, clinopyroxene-garnet skarn, garnet skarn and vesuvianite skarn zone. The ore mineral, scheelite, disseminates in the clinopyroxene-garnet and vesuvianite skarn zone, and the size of the scheelite crystals in vesuvianite skarn zone is larger than in clinopyroxene- garnet skarn zone. According to the mineral paragenesis and the composition of skarn minerals, oxygen fugacity (fo₂) is low. Fluid inclusions in quartz comprise much LCO₂ and fluid inclusion studies revealed that the homogenization temperatures range 240-290℃.