한반도 남서부 남원 일대에 분포하는 A형 대강 화강암의 암석학,지화학 및 지구조적 의미

Daegang granite is located around the Namwon-gun, Cheolabuk-do, and is an elongate stock (80㎢) in the NNE-SSW direction. Daegang granite has the very same mineralogical and geochemical characteristics as those of the typical A-type granites; (1) it is a one feldspar hypersolves granite, and is classified as an alkali feldspar granite in the IUGS scheme , (2) has small amounts of Fe-rich biotite (annite) and alkali amphibole (ribeckite) that are late in the crystallization sequence of the granitic magma, (3) always contains opaque oxides, fluorite and zircon, (4) shows high and quite homogeneous SiO₂content (mostly 72∼77 wt.%) and (Na₂O+K₂O)/Al₂O₃ratio (0.90∼0.98), (5) contains high Ga, 10000*Ga/Al, K₂O+Na₂O, (K₂O+Ma₂O)/CaO, K₂O/MgO, FeO/MgO, agpaitic index, Zr, Nb, Ce, Y, Zn value or ratio that resemble to those of the Australian A-type granites (Whalen et al., 1987), and (6) has enriched LREE and HREE that show flat variation pattern with slightly depleted in HREE and profround Eu anomalies (Eu/Eu=0.04∼0.14). In the tectonic discrimination diagrams of Pearce et al. (1984) and Eby (1992), Eaegang granite is classified as a within plate granite and A₂-type.