聞慶 南部一帶에 分布하는 白惡紀 花崗岩類의 岩石學 및 岩石化學

Petrology and Petrochemistry of the Cretaceous Granites in the Southern Mungyeong Area

The Cretaceous granites are widely distributed in the studied area, Mungyeong-Sangju, which belongs to the southwestern part of the Ogcheon Folded Belt. The granites are characterized by medium-coarse grained, spotted miaroles, partly flow textures of biotite, aplitic dykes and pegmatitic pockets with druse. From the major compositions, the granites indicate peraluminous, calc-alkaline, salic and late stage products of differentiation. In the view of normative compositions of Qz-Ab-Or and perthitic alkali feldspar, they were formed under 1-4kb and 426°-456℃ in acqueous conditions. The K/ Ar biotite age shows 72±1 Ma for this grante, corresponding to the igneous activity of the Bulgugsa Disturbance periods in the area. The above results represent that these granite bodies are differentiated from a single magma.