• 한국지구과학회:학술대회논문집
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• 2005.09a
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• pp.32-39
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• 2005

최근 들어 북한 서해안 일대의 원유매장 가능성에 대한 보도가 국내외 언론에 자주 오르내리고 있다. 실제 북한의 서한만 분지는 일일 생산량 450 배럴의 원유가 생산되고 있어 석유부존 가능성이 확인되었고, 중국에서 큰 유전중 하나인 발해만 유전지대와 지리적으로 근접해 있어 대규모 매장 가능성도 있다. 지금까지 밝혀진 북한 서한만의 지질은 중국의 발해만과 유사하다. 후기 원생대와 초기 고생대에 생성된 기반암 위에는 최대 6 ${\sim}$ 10 km 두께의 탄산염암 및 중생대 퇴적암과 4 ${\sim}$ 5 km 두께의 퇴적암이 집적되어 있다. 근원암은 3 km 이상 되는 쥐라기 흑색 셰일과 1 ${\sim}$ 2 km 두께의 백악기 흑색 셰일 그리고 수 km 두께의 중생대 이전의 탄산염암으로 구성되어 있다. 저류층은 높은 공극률을 가진 중생대부터 신생대에 퇴적된 사암과 중생대전에 균열된 탄산염암이다. 원유 트랩은 배사구조, 단층구조, 파묻혀 있는 언덕 그리고 층서형 트랩 형태다. 따라서 서한만에서의 퇴적층들은 다양한 형태의 근원암을 가지며 또한 공극률과 투수율이 높고, 많은 단층에 의한 이동경로를 가지게 되므로, 사암으로 이루어진 석유 저장지만 발견하면 석유를 생산할 수 있을 것으로 추정된다.

• Geophysics and Geophysical Exploration
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• v.16 no.1
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• pp.36-44
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• 2013

We conducted the airborne magnetic and radiometric survey for the characterization of the black shale related and pyrometamorphic uranium deposits distributed in Geumsan area. For the successful characterization of the uranium deposits, the general geological and structural geological features were investigated based on the lithological and linear feature analysis to individual magnetic and radiometric data as the first step. Lithological analysis from the magnetic reduction to the pole and downward continuation map revealed that prominent positive anomalies caused by black and dark gray slate member were clearly recognized as magnetic sources. These results indicate that magnetic survey, even though it is not a direct method for the detection of uranium, can be a useful tool in uranium detection. By the linear feature analysis based on 2nd vertical derivative and curvature map, two linearments corresponded the gray hornfels and black slate member were extracted and in succession, the additional uranium potential zone was inferred. Final discrimination whether uranium-rich or not was confirmed by radiometric and uranium anomaly map. From these analysis, we finally concluded that uranium deposit originated by pyrometamorphic process was confined near the intrusive area only. On the contrary, it was found that black shale related uranium deposit is distributed and extended through out the entire survey area with south-west to north-east direction. In addition, from the linear feature analysis based on radiometric total anomaly map, the typical discontinuous characteristics were recognized in areas where uranium-contained linearments cross the faults. From the above discussion, we concluded that airborne magnetic and radiometric survey are complementary to each other. So it is preferable to carry out simultaneously for the efficient data processing and fruitful interpretation.

• Journal of the Korean earth science society
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• v.21 no.6
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• pp.683-694
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• 2000

Abstrace: The palaeodepositional environment and age of the Cretaceous Hampyeong Basin (southwestern Korea) are reassessed based on new geochemical, lithological, sedimentological, and palaeobotanical data. Results indicate that the Hampyeong Basin was a tectonically active basin comprising predominantly fluvial and lacustrine sediments. Four distinctive facies types have been identified (acidic tuff, black shales/sandstones, red beds, intermediate tuff with tuffaceous conglomerate) and these reflect periods of significant environmental change within the basin and its neighbouring terrains. Volcanism driven by tectonic events provides a source for much of the sediment. The sedimentary sequences compare well with those in the neighbouring Haenam Basin. Sediments of volcanic origin are similar to those of the Neungju Formation of the Yuchon Group. The widespread occurrence of black shales is indicative of extended periods of deposition under anoxic conditions. Measurements of total organic carbon show that the values for the black shales (0.81% to 1.75%) are the average for petroleum source shales. Fossil plants occurred in the black shales and sandstones. The occurrence of platanoid leaves places these sediments in Oishi's angiosperm series, which is consistent with an Aptian/Albian or younger age.

• Geophysics and Geophysical Exploration
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• v.17 no.2
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• pp.49-57
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• 2014

3D magnetic inversion, based on the assemblage of 2D forward modeling and inversion as a practical technique to reflect the a priori information, was conducted to investigate the spatial distribution features of black-shale related and pyrometamorphic uranium deposit and several lithological units of Ogcheon Super Group in an area of Geumsan. By using the 3D visualization technique with suitable susceptibility interval and horizontal slice map, the spatial distribution of magnetic susceptibility corresponded to the black shale related uranium bearing lithological units, Black Slate member was well coincided with a information of uranium deposit. Also, even though it is indirect indicator for the detetction of uranium deposits interbedded in Gray Hornfels member, spatial susceptibility distribution which shows the south-east magnetic linearment corresponding to the Majeon-ri formation and Dark Gray Slate were matched well. From this investigation, we inferred that maximum depth extension which Black Slate member can be separately recognized with respect to adjacent Dark Gray Slate with strong magnetic susceptibility anomaly is about 150m with reference elevation level of 306m. In addition, Majeon-ri formation located south of Black Slate member revels relatively high magnetic susceptibility range but shows high spatial susceptibility fluctation. And, as an intrusive rocks, Jurassic Biotite Granite shows relatively low magnetic susceptibility characteristics. On the contrary, Cretaceous granite distributed in soutthern part of the study area shows the relatively high susceptibility distribution.

• Journal of the Mineralogical Society of Korea
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• v.8 no.2
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• pp.108-117
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• 1995

옥천층군의 상부 이질암에 속하는 구룡산층내의 함흑연질셰일층준에서 흑연단괴가 산출된다. 이들 중 덕평과 조곡지역에서 산출되는 흑연질단괴는 두 지역 모두 장경 2cm 이하의 타원체가 주이며, 조곡지역의 단괴가 덕평지역의 단괴에 비하여 더욱 신장되어 있다. 덕평지역에서는 단괴가 초기 속성기간 중에 생성된 것임을 지시해 주는 조직이 단괴와 모암의 접촉부에서 관찰되는 반면 조곡지역에서는 이러한 조직이 관찰되지 않는다. 덕평지역 단괴의 주구성 광물은흑연, 인회석, 석영, 운모이고 조곡지역 단괴의 구성광물은 흑연, 석영, 운모이다. 덕평 및 조곡지역에서 산출되는 단괴내의 총탄소함량은 각각 40%, 5% 내외의 값을 갖는다. 덕평 및 조곡지역의 탄질물의 d002는 동인한 3.356~3.360$\AA$의 범위의 값을 가진다. 이는 고진화된 흑연의 저면간격에 해당되는 것으로, 두 지역의 변성상이 동일함을 의미한다.

• Journal of Korean Society of Forest Science
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• v.108 no.2
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• pp.216-223
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• 2019

This study was conducted to measure the changes in the geological and soil properties following slow-moving landslide events in Yangbuk-myun and Gyungju-si, Gyeongsangbuk-do, South Korea. The geological characteristics of the study site comprised black shale in the Gyeongsang nodal group formed in the Cretaceous period and quartz feldspar carcinoma in the east side with conglomerate in the Yeonil group formed in the Quaternary period. The study site exhibited the geologic characteristics of a slow-moving landslide with severely weathered rocks. The maximum collapsing depth of the slow-moving landslide was 12.0 m with colluvial deposits. The strike and joint aspects in the slope areas of the slow-moving landslides were $N46^{\circ}E$ in lower slope and $N62^{\circ}E$ in upper slope, respectively. Soil hardness of ${\leq}20cm$ deep was not measured because of the completely disturbed soil resulting from soil creeping. Soil from 25 to 90 cm deep was 1.4-4.7 times softer in the slow-moving landslide areas than in the undisturbed or natural forests. Soil bulk density was $1.24-1.29g/cm^3$ in land creep areas. Soil bulk in both areas was 1.6 times denser than that in the natural forest. The soil pore space was 51.5-53.3% in the land creep areas. The values are 1.3-1.4 times lower than those within the natural forest. Black shale areas showed the lowest coefficient of permeability (8.75 E-06 cm/s) and mesopore ratio (pF 2.7: 9.8%) compared with those resulting from other study areas.

• Economic and Environmental Geology
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• v.30 no.6
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• pp.587-601
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• 1997

This study had three purposes: (1) to investigate the enrichment levels and dispersion patterns of potentially toxic elements in the rock-soil-plant system; (2) to evaluate the uptake ratios of heavy metals from soils into plants and (3) to assess the chemical speciation of heavy metals in soils. Rock, surface soil and plant samples were collected in the Boeun area underlain by black shales of the Okchon Zone. These samples were analyzed for multi-elements using INAA, ICP-AES and AAS. The maximum abundance of U in black shales is 16 mg/kg and radioactivity counts up to 300 cpm. In particular, Mo, V, Ba, Cd, Pb and U are enriched in black shales. Most of soils derived from black shales show high concentrations of U, As, Mo, Ba, Cu, Cd, Pb, Zn and mean concentrations of As and Mo in soils (20 mg/kg of As and 6.6 mg/kg of Mo) are higher than the permissible level suggested by Kloke (1979). Enrichment index values of soils are calculated and higher than 1.0 in the black shale area with the highest value of 6.4. Mean concentration of Cd in plants is higher than those of Cu, Pb and Zn. The concentration of Cd in plant species decreases in the order of Chinese cabbage > red pepper > soybean=sesame > rice stalk > com > rice grain. The biological absorption coefficients (BAC) in plants are in the order of Cd > Zn=Cu > Pb, which suggests that Cd is more bioavailable to plants than Cu, Pb and Zn. From the results of sequential extraction analysis of soils, relatively high proportion of Cu, Pb and Zn are present as residual fractions whereas that of Cd as non-residual fractions. Cadmuim occurs predominantly as exchangeable/water-acid soluble phase in soils, and Cd is more mobile and bioavailable than Cu, Pb and Zn.

• Economic and Environmental Geology
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• v.30 no.2
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• pp.89-103
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• 1997

The purpose of this research is to investigate the enrichment and distribution patterns of naturally occurring potentially toxic elements in soils derived from black shales and slates. Soil samples were collected from the Chubu area covered with uranium-enriched black shales and slates of the Changri Formation of the Okchon Super Group, and analysed for multiple-elements using INAA, ICP-AES and AAS. Soil pH and loss-an-ignition were also measured. Trace element contents in black shale and slate of the Chubu area are relatively lower than those in black shales, and higher than those in black slates reported elsewhere (Chon, Jung, 1991; Chon et al., 1996). Soil pH values range from 3.5 to 6.5, and loss-an-ignition values are in the range from 3 to 10%. Potentially toxic elements including As, Ba, Cr, Cu, Mo and U are highly enriched in residual soils with maximum content of $540{\mu}g/g$, $35,000{\mu}g/g$, $280{\mu}g/g$, $300{\mu}g/g$, $240{\mu}g/g$ and $860{\mu}g/g$, respectively. Significant concentrations of those elements were found in soils taken from the Tojangkol, the Chubu tunnel and the Meokti areas. Soils derived from black shales and slates, calcareous and phyllitic rocks, and intrusions were discriminated in terms of As, Ba, Co, Cr, Cu, Mo, Sc and U contents. Enrichment index was calculated using the concentrations of As, Ba, Cr and Mo, and enrichment index map shows very similar trend with U distribution in soils.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.495-508
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• 1996

This study had three purposes: (1) to investigate dispersion and enrichment level of potentially toxic elements; (2) to identify uranium-bearing minerals in black shales; and (3) to assess the chemical speciation of heavy metals in soils and sediments. Rock, surface soil and stream sediment samples were collected in the Chungjoo area covered with black shales in Korea. These samples were analyzed for multi-elements using INAA and ICP-AES. The maximum abundance of U in black shales is 56 ppm and radioactivity counts up to 240CPM. Molybdenum, V, Ba, Cu, and Pb are enriched in black shales and most of soils show high concentrations of U, Mo, Ba, Cu, Pb and Zn. Concentrations of potentially toxic elements decrease in the order of mountain soil > farmland soil > paddy soil. Enrichment index of soils and sediments are calculated and higher than 1.0 in the black shale area with the highest value of 6.1. In order to identify U-bearing minerals, electron probe micro analysis was applied, and uraninite and brannerite in black shale were found. Uraninite grains are closely associated with monazite or pyrite with the size of $2{\mu}m$ to $10{\mu}m$ in diameter whereas brannerite occurs as $50{\mu}m$ euhedral grains. With the results of sequential extraction scheme, residual fractions of Cu, Pb and Zn in soils are mainly derived from weathering of black shale but Cu, Pb and Zn in sediments are present as non-residual fractions. Lead is predominantly present as oxidizable phase in soils whereas Zn is in exchageable/water-acid soluble phase in sediments.

• The Korean Journal of Petroleum Geology
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• v.12 no.1
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• pp.1-8
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• 2006

Jiaolai Basin is the Cretaceous continental sedimentary basin developed in Shandong Province of China. It is interpreted as a pull-apart basin which is filled with fluvio-lacustrine sediments and volcanic rocks. The sedimentary strata are divided into three formations: Laiyang Formation, Qingshan Formation and Wangshi Formation in ascending order. Laiyang Formation of the early Cretaceous consists of conglomerate, sandstone and shale, which are grey, black or red in color, respectively. Qingshan Formation of early Cretaceous includes various kinds of volcanic rocks. Late Cretaceous Wangshi Formation consists of red conglomerate, sandstone and shale. Various types of oil shows are observed on many outcrops in the basin such as asphalt filing fissures, oil smelling, rocks wetted with oil. However, commercial oil discovery was not made. Laiyang Formation is the richest in terms of organic matter contents. Some grey or black shales of Laiyang Formation contain more than 1% of organic matter. Kerogens of some layers mainly consist of amorphous organic matter or pollen. Thermal maturity of the organic matter reached main oil generation zone and hydrocarbon genetic potential is fairly good. According to such geochemical data, some layers of Laiyang Formation can act as hydrocarbon source rocks.