대유 페그마타이트광상의 광물조성과 K-Ar 연대

• 발행기관: 대한자원환경지질학회
• 저자명: 신홍자
• 간행물 정보: 『자원환경지질』32권 3호, 227~236쪽, 전체 10쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1999.06.30

영문 초록

The Daeyou pegmatite is located at the central westerm part of the peninsula. Geology of the mine area consists mainy of pre-Combrian granite gneiss and leucoratic gneiss which are intruded by Mesozoic granites. The pegmatite deposits occur within granite gneiss. Most of pegmatites contain quartz, perthite, microcline-perthite, microcline, sodic plagioclase and tourmaline as dominant minerals with accessory minerals of mica (muscovite, biotite, sericite)and pyrite. Tourmaline occurs as four types: 1) unaltered single crystals, 2) patially sericitized grains bordered by sericite assemblage, 3) tourmaline intergrown with feldspar and qurtz grains, and 4) tourmaline introduced veinlet/ On the basic of optical, X-ray diffraction and chemical analysis, the composition of tourmaline mostly falls on the schorl-elbaite join, in the composition of tourmaline mostly falls on the schorl-elbraite join, in the composition of schorl end member from 0 to about 50%. In spite of the different occurrences, chemical composition of tourmaline shows the limited ranges as follows: SiO2 (34.53∼35.01 wt.%), Al2O3(33.58∼34.26wt.%), FeO (13.73∼14.17wt.%), Na2O (1.60∼1.72wt.%), MgO (0.56∼0.72wt.%), MnO (0.12∼0.18wt.%), CaO (0.02∼0.06wt.%), K2O(0.02∼0.05wt.%) and Cr2O3(0.02∼0.03wt.%). K-Ar ages of the muscovite and sericite fall between 1010±15 and 1074±16Ma and between 161.56±3.09 and 161.67±Ma, respectivrly. This means that hydrothrmal alteration occurred during middle Jurassic, whereas the pegmatite was initally formed during the late proterozoic age.

키워드

페그마타이트광상 K-Ar 연대, 대유광산 공생관계