계명산층 페그마타이트에 수반되는 우라늄,토륨 광상의 지구화학적 특성

• 발행기관: 대한자원환경지질학회
• 저자명: 박맹언 김근수
• 간행물 정보: 『자원환경지질』31권 5호, 365~374쪽, 전체 10쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1998.10.30

영문 초록

Economic U-and Th-bearing pegmatite deposits occur in the Kyemyeongsan Formation, and are spatially closely associated with the Carboniferous alkali granite. The pegmatite is lithochemically alkaline and peralumious, and consists mainly of potassic feldspar and quartz with allanite and U- and Th-bearing minerals. Paragenetic stages of mineralization in the pegmatite are divided as follows: carly silicate mineralization, main rare metal mineralization, and late silicate mineralization. Thorite, euxenite, fergusonite and uranpyrochlore are the predominant U- and Th-bearing minerals. Both the enrichements of Nb, Y, Th, U, and Ta and the depletions of Hf, Ba, and Rb in the pegmatite were resulted form magmatic differentiation. The increases of Na and Ca in uranpyrochlore, of Th and U in fergusonite, of Si, Th, U and Pb in thorite, and of Nb and Y in euxenite were possibly resulted from both later internal fractionation and hydrothermal alteration. The variation of chemical composition in a mineral species reflects the different pysico-chemical conditions during the crystallization.

키워드

우라늄 계명산층 페그마타이트,토륨 산성관입체 변성암 섬장암 충주 고생대 희류원소 U-Th군