우리나라 南部地域에 分布하는 生産性 深成岩體에 대한 岩石地化學的 硏究 : 光陽, 突山, 南海 地域을 中心으로

다국어 초록 (Multilingual Abstract)

The Cretaceous granitoids related to base metal mineralization in the studied area consist of hornblende - biotite granite, leucocratic granite and micrographic granite. The major - and trace element data from granitoids, when plotted on the Hacker diagram, average contents of Al₂O₃, CaO, Mg0 and Fe₂O₃ decrease while SiO₂ increases in granitoids from Dolsan toward Namhae and Kwangyang areas. Average content of Rb is higher in Kwangyang area while Ba and Sr decrease in granitoids from Dolsan toward Namhae and Kwangyang, and as shown in triangular diagram of RbBa-Sr, which indicates gradual differentiation of granitic magma from Dolsan toward Namhae and Kwangyang. And, studies of major element variation, calc-alkaline index(61.5) and AFM diagram of granitoids indicates that granitoids have been crystallized from a calc-alkaline magma generated by partial melting of the subducted Pacific Oceanic Crust(or Kula plate) at the compressional plate margin, that is, the volcanic arc. Na₂O/K₂O ratio and magnetic susceptibility of granitoids indicate that they belong to I-type and magnetite series. As shown in atoms against pressure diagram, variation to the number of cations Al^(4+) Al^(6+), (Al+Fe^(3+)^(6+), Si, (Mg+Fe^(2+)), and A-site (Na+K) in amphiboles are shown as functions of estimated crystallization pressure, which the amphibole in granitoids crystallized in the pressure range of 1.8 - 3.0 kbar. According to the two-feldspar geothermometry on granitoids of Kwangyang, Dolsan and Namhae areas, the temperature of cessation of exsolution in perthitic alkali feldspars are 476 - 607℃, 489 - 640℃ and 465 - 629℃, respectively, at assumed pressure of 3 kbar, which may be the result of rapid crystallization in the shallow crustal level(5 - 7.5 ㎞).