沃川帶 우라늄鑛層의 構造規制 및 地球化學的 特性硏究

• 영문명: Lithologic and structural controls and geochemistry of uranium deposition in the Ogcheon black-slate formation
• 발행기관: 대한자원환경지질학회
• 저자명: Dai Sung Lee(李大聲) Suckew Yun(尹碩奎) Jong Hyeog Lee(李鍾革) Jeong Taeg Kim(金正澤)
• 간행물 정보: 『자원환경지질』19권 5호, 19~41쪽, 전체 23쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1986.10.30

영문 초록

Structural, radioactive, petrological, petrochemical, mineralogical and stable isotopic study as well as the review of previous studies of the uranium-bearing slates in the Ogcheon sequence were carried out to examine the lithological and structural controls, and geochemical environment in the uranium deposition in the sequence. And the study was extended to the coal-bearing formation (Jangseong Series-Permian) to compare the geochemical and sedimentologic aspects of uranium chemistry between Ogcheon and Hambaegsan areas. The results obtained are as follows: 1. The uranium mineralization occurs in the carbonaceous black slates of the middle to lower Guryongsan formation and its equivalents in the Ogcheon sequence. In general, two or three uranium-bearing carbonaceous beds are found with about 1 to 1.5km stratigraphic interval and they extend from Chungju to Jinsan for 90km in distance, with intermittent igneous intrusions and structural disturbances. Average thickness of the beds ranges from 20 to 1,500m. 2. These carbonaceous slate beds were folded by a strong F₁-fold and were refolded by subsequent F₁-fold, nearly co-axial with the F₁, resulting in a repeated occurrence of similar slate. The carbonaceous beds were swelled in hing zones and were shrinked or thined out in limb by the these foldings. Minor faulting and brecciation of the carbonaceous beds were followed causing metamorphism of these beds and secondary migration and alteration of uranium minerals and their close associations. 3. Uranium-rich zones with high radioactive anomalies are found in Chungju, Deogpyong-Yongyuri, Miwon-Boun, Daejeon-Geumsan areas in the range of 500~3,700 cps(corresponds to 0.017~0.087%U). These zones continue along strike of the beds for several tens to a few hundred meters but also discontinue with swelling and pinches at places that should be analogously developed toward underground in their vertical extentions. The drilling surveyings in those area, more than 120 holes, indicate that the depth-frequency to uranium rich bed ranging 40~160 meter is greater. 4. The features that higher radioactive anomalies occur particularly from the carbonaceous beds among the argillaceous lithologic units, are well demonstrated on the cross sections of the lithology and radioactive values of the major uranium deposits in the Ogcheon zone. However, one anomalous radioactive zone is found in a hornfels bed in Samgoe, near Daejeon city. This is interpreted as a thermal metamorphic effect by which original uranium contents in the underlying black slate were migrated into the hornfels bed. 5. Principal minerals of the uranium-bearing black slates are quartz, serieite, biotite and chlorite, and as to chemical composition of the black slates, Al₂O₃ contents appear to be much lower than the average values by its clarke suggesting that the Changri basin has rather proximal to its source area. 6. The uranium-bearing carbonaceous beds contain minor amounts of phosphorite minerals, pyrite, pyrrhotite and other sulfides but not contain iron oxides, Vanadium. Molybdenum, Barium, Nickel, Zirconium, Lead, Cromium and fixed Carbon, and some other heavy metals appear to be positive by correlative with uranium in their concentrations, suggesting a possibility of their genetic relationships. The estimated pH and Eh of the slate suggests an euxenic marine to organic-rich saline water environment during uranium was deposited in the middle part of Ogcheon zone. 7. The Carboniferous shale of Jangseong Series(Sadong Series) of Permian in Hambaegsan area having low radioactivity and in fluvial to beach deposits is entirely different in geochemical property and depositional environment from the middle part of Ogcheon zone, so-called “Pibanryong-Type Ogcheon Zone”. 8. Synthesizing various data obtained by several aspects of research on uranium mineralization in the studied sequence, it is concluded that the processes of uranium deposition were incorporated with r

목차

Abstract

서론

함우라늄 암층의 일반지질

지질구조

방사능 이상대

옥천대 함우라늄 암층의 화학성분

함백산 지구 탄질 흑색셰일

피반령대와 함백산대의 비교

결론

參考文獻