The Mesozoic leucocratic granite in the northeastern margin of the Taebaeksan Basin was transformed to protomylonite and mylonite. Mylonitic foliations generally strike to NWWNW and dip to NE with the development of a sinistral strike-slip (top-to-the-northwest) shear sense. Grain-size reduction of feldspar in the mylonitized leucocratic granite occurred due to fracturing, myrmekite formation and neocrystallization of albitic plagioclase along the shear fractures of K-feldspar porphyroclasts. As the deformation proceeded, compositional layering consisting of feldspar-, quartz- and/or muscovite-rich layers developed in the mylonite. In the feldspar-rich layer, fine-grained albitic plagioclase and interstitial K-feldspar were deformed dominantly by granular flow. On the other hand, quartz-rich layers containing core-mantle and quartz ribbons structures were deformed by dislocation creep. Based on calculations from conventional two-feldspar and ternary feldspar geothermometers, mylonitization temperatures of the leucocratic granite range from 360 to 450˚C. It thus indicates that the mylonitization has occurred under greenschist-facies conditions. Based on the geochemical features and previous chronological data, the leucocratic granite was emplaced during the Middle Jurassic at volcanic arc setting associated with crustal thickening. And then the mylonitization of the granite occurred during the late Middle to Late Jurassic (150-165 Ma). Therefore, the mylonitization of the Jurassic granitoids in the Taebaeksan Basin was closely related to the development of the Honam shear zone.

현재 에메랄드의 중요한 산지로 자리 잡아가고 있는 Itabira 지역 에메랄드의 분광학적 특성을 연구하기 위하여 에메랄드를 C-축에 수직, 수평인 방향으로 각각 절단하였으며, H2O 관련 범위의 좀더 세부적인 피크 관찰을 위하여 KBr로 압축한 pellet시료를 만들어 적외선 분광분석(FTIR) 실험을 수행하였다. H2O 관련 범위에서 5,271 cm-1, 1,638 cm-1 피크가 나타나는 것으로 보아 본 시료는 Type-II에 해당함을 관찰할 수 있었으며, H2O-Na-H2O 배열 형태를 가지는 Type-IIa에 해당하는 피크가 아주 강하게 나타나고 있다. H2O 관련 범위를 제외한 특정 범위에서는 CO2, Cl 피크 등이 관찰되었으며, 적외선 분광분석 법을 이용하여 타입의 분류뿐만 아니라 상대적인 피크 강도 비교를 통하여 Na2O 함량 또한 예측 가능한 것으로 사료된다.