• 자원환경지질
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• 제30권6호
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• pp.553-566
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• 1997

Origin, behavior and enrichment of environmental toxic elements from the Deokpyeong area were investigated on the basis of major, trace and rare earth element geochemistry. Coaly metapelites of the Deokpyeong area are subdivided into grey phyllite, dark grey phyllite, coaly slate and black slate, which are interbedded along the Ogcheon Supergroup. The coaly slate had been mined for coal, but mining is closed. The coaly and black slates are lower contents of $SiO_2$ and $Al_2O_3$, and higher contents of LOI, CaO, $Na_2O$ and BaO as compared with the phyllitic rocks. Rare earth elements are highly enriched in the coaly and black slate. Average compositions (ppm) of minor and/or environmental toxic elements in the coaly and black slate are revealed as As=127, Ba=30,163, Cd=18, Cr=740, Cu=84, Mo=378, Pb=43, Sb=12, Se=44, U=144, V=8,147 and Zn=292, which are extremely high concentrations than those in the NASC compositions. Major elements (average enrichment index; 5.34) in the coaly metapelites are mostly depleted, excepting $P_2O_5$ and BaO, normalized by NASC. Rare earth elements (average enrichment index; 1.48) are enriched in the coaly slate. On the basis of NASC, minor and/or environmental toxic elements in the coaly metapelites were strongly enriched of all the elements with the exception of Co, Cs, Ni and Sr. Average enrichment index of trace elements in coaly metapelite is 31.51 (coaly slate; 51.94 and black slate; 15.46). Especially, enrichment index of potentially toxic elements (As, Ba, Cr, Cu, Mo, Ni, Sb, Se, U, V and Zn) of the rock is 46.10 (grey phyllite; 7.15, dark grey phyllite; 4.77, coaly slate; 88.96 and black slate; 22.11). These coal formations were deposited in basin of boundary between terrestrial and marine environments deduced to carbon, sulfur (C/S=2.2 to 275.7), trace and rare earth elements characteristics. Irregular behavior and dispersion between major, minor and rare earth elements of those metapelites indicates a variable source materials, incomplete mixing of differential source and/or reequilibrium of diagenesis and metamorphism.

• 자원환경지질
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• 제18권2호
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• pp.135-138
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• 1985

The radioautographing of U-bearing cloaly slate samples were initiated in order to clarify the uranium distribution patterns in the samples of Ogcheon system. Moreover, x-ray powder diffraction and x-ray single crystal analysis studies were undertaken to identify the uranium mineral which was extracted from U-bearing coaly slate. The handspecimens were collected from the Boseong mine, located in Deokpyeong area, Goesan-gun, Chungcheongbug-do. According to the experimental studies, it has been found the following facts: (1) fixed carbon has close relation with uranium contents, (2) quartz veins developed in U-bearing coaly slate are diveded into two groups based on mode of occurrence, formation stage and uranium distribution pattern; early quartz vein ($QV_1$) with low uranium concentration and late quartz vein ($QV_2$) with high uranium concentration, (3) matrixes around $QV_1$ are displayed homogeneous and high uranium concentration, while matrixes around $QV_2$ are low uranium concentration, (4) uranium mineral is identified as a variety of autunite.

• 지질공학
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• 제24권1호
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• pp.137-146
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• 2014

연구지역의 지질은 흑색천매암, 석회암 및 함역천매암과 중생대 관입안인 흑운모화강암과 석영반암으로 구성되어 있다. 이 중 흑색천매암이 분포하는 구간에서 건설 중인 도로 사면에서 절토사면 현황도(face map)를 4월부터 6월까지 3개월간 작성하였으며 이때 탄질슬레이트 분포지 부근을 포함 사면 내에는 3-4개소에서 사면붕괴와 산 정상부에는 최고 3 m의 변위를 보이며 움직이고 있음이 확인 되었다. 사면 붕괴의 원인은 엽리 및 단층 등의 불연속면의 경사방향이 사면의 경사방향과 일치하는 곳에서 붕괴가 발생하였고 탄질 슬레이트는 빗물을 머금을 때 팽창성을 가짐도 붕괴가 일어나는 원인이다. 반면 본 사면의 도로 맞은편 사면에서는 같은 암상 및 지질구조 조건을 가지고 있으나 엽리 및 불연속면들의 경사 방향이 사면의 경사 방향과 반대방향이므로 안정된 사면을 유지하고 있다. 사면의 붕괴가 일어난 곳에서 안정화를 위해 절개 후 복구(cut and cover) 방법으로 도로의 양쪽 사면 사이 도로 상에 터널 구조물을 설치하여 절개식 터널(cut and cover tunnel)을 시공하였으며 시공 후 사면은 안정화 되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.51-60
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• 2006

At new constructing national road, a cutting slope was surveyed and gotten face mapping for three months. The slope is composed of gray phyllite and coaly slate which is the Chang-ri Formation, Okcheon system. The slope angle is 40 degree and the direction is NNE. The attitude of schistosity is $260^{\circ}/45^{\circ}$. So the slope direction is nearly parallel to the schistosity. This is the reason that the slope is very unstable. On the other hand, the very unstable slope is caused by the direction of the schistosity and the slope. First month the coaly slate was slided through the schistosity plane about 10cm. However, three months late the displacement was 2m maximum.

• 자원환경지질
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• 제44권5호
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• pp.373-386
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• 2011

옥천변성대의 대표적인 우라늄 광화대인 괴산군 덕평리 일대의 흑색점판암과 이에 협재하는 함우라늄 탄질점판암을 상호 구분하여 이들에 대한 지구화학적 연구를 수행함으로써 우라늄 광상의 생성환경에 대해 고찰하였다. 희토류원소 함량은 탄칠점판암이 평균 254 ppm로서 혹색점판암(169 ppm) 보다 높고, 표준시료로 표준화한 결과 탄질시료의 Eu이 현저히 부화되어 나타난다. 산화환원지시원소에 해당하는 원소들의 경우 V, Cr, Co, Ni, Mo, 및 U 등이 흑색점판암에 비해 탄질점판암에서 현저히 부화되어 있는데, 특히, V은 흑색점판암에 비해 24배, Mo은 62배, U은 60배 가량 높게 산출된다. 이 밖에 백금족원소의 경우 Pd와 Pt가 탄질점판암에서 높은 함량을 나타낸다. 정의 Eu 이상을 비롯해 표준 해수기원 셰일에 비해 현저히 부화된 상기 원소들의 산출은 이들이 단순한 해수로부터 침전된 것이 아닌 고온의 환원환경인 해저열수활동과 관련된 퇴적환경에서 생성되었음을 시사한다. 넓은 조성변화를 나타내는 주성분 원소비 ($SiO_2/Al_2O_3$: 3.98~11.88, $Al_2O_3/Na_2O$: 25.6~139.06, $K_2O/Na_2O$: 6.80~46.85)도 퇴적물의 근원암이 퇴적암과 화성암이 혼재되었을 가능성을 나타내며, 또한 황의 함량이 흑색점판암에서 평균 0.6 wt.%인 반면, 탄질점판 암에서는 2.6 wt.%로 높게 나타나는 것은 탄질점판암이 황을 다량 포함하는 열수환경의 영향을 받았음을 보여준다. 이와 같은 지화학적 특징은 옥천변성대와 지구조적으로 대비되며 퇴적분기성 기원으로 알려진 남중국형 백금족광상(Mo-Ni-Zn-PGE)의 생성환경과도 유사한 특징이다. 이상으로 보아 덕평려 일대 우라늄광화작용은 해저열수활동의 영향을 받고 산소가 결핍된 유기물이 풍부한 퇴적분지에서 형성된 것으로 해석된다.

• 자원환경지질
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• 제19권spc호
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• pp.163-173
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• 1986

Black and graphite slates from the Okcheon metamorphic belt contain enriched values of uranium (average 200~250ppm) and molybdenum (average 150~200ppm). Uranium mineralization is closely associated with quartz and sulfide veinlets which are formed diagenetically in graphite slate. The uranium minerals were concentrated in outer part of graphite nodules. The ${\delta}^{13}C$ values of organic carbon from the metasediments including uranium bearing graphite slate range from -15.2 to -26.1‰ with a mean of -23.5‰. Meanwhile, ${\delta}^{13}C$ values of coal and coaly shale from some Paleozoic coal fields of South Korea vary from -19.4 to -23.9‰ with an average of -22.5‰. Isotopic compositions of vein calcite in uranium bearing slate range from -13.4 to -15.4‰ in ${\delta}^{13}C$ and +11.3 to +15.1‰ in ${\delta}^{18}O$ could indicate a reduced organic carbon source isotopically exchanged with a graphite of biogenic origin. Metamorphic temperature determined by a calcite-graphite isotope geothermometer was 383~$433^{\circ}C$ which corresponded to greenschist facies by Miyashiro (1973) and is consistent with metamorphic facies estimated by mineral assemblages (Lee, et al., 1981, and Kim, 1971). The fixation of uranyl species by carbonaceous matter in marine epicontinental environment, and remobilization of organouranium by diagenetic processes have attributed to the enrichment of uranium and heavy metals in the graphite slate of Okcheon metamorphic belt.

• 자원환경지질
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• 제13권4호
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• pp.215-227
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• 1980

The rock units of Goesan area in the Ogcheon metamor phic terrain established on the basis of field criteria should be redefined into following sequence. Based on shear senses in secondary small structures which are usually observable in the investigated area, the stratigraphy can be lithologically divided into the lower pelite, pebbly mudstone, upper pelite, quartzite and psammite unit in ascending order. This conclusion is in discordance with a previous opinion; Munjuri formation and Guryongsan formation may be equivalent to upper pelite unit, Iwonri formation and Hwanggangri formation to pebbly mudstone. From this, it may be inferred that isoclinal overturned folds repeatly occur in the area. The uranium bearing coaly thin layers in upper pelite unit have relatively broad exposures in Deogpyeongri block of Goesan area along culmination zone in the central part of the investigated area. It is believed that structural feature in the block recognized complexly refolded synform plunging to southwest. Mineralogical and radiometric studies were made on 135 representative samples from the Ogcheon Group of Korea. The mineralogy of all black slate samples is qualitatively similar but quantitatively ·different. The uranium distribution in the studied area show approximately log normal. Uranium in the black slates of the Ogcheon Group was deposited together under same physico-chemical environmental conditions. The chemical and geological factors that controlled the abundance of organic carbon and iron oxides also controlled the uranium content. The relationship of the major components to uranium can be expressed by the following regression equation: $Log(U\times10^4+1)$= 1.70999-0.00367(quartz)0.00512(micas)-0.00930 (other silicates)+0.01911 (iron oxides)-0.03389(other opaques)+0.02062(organic carbon).