• 광물과 암석
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• 제36권4호
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• pp.323-336
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• 2023

핵심 광물인 니켈의 국내 확보를 위해 충남 유구지역 초염기성암에 대한 니켈 잠재성 및 성인 연구를 수행하였다. 경기육괴의 남서쪽에 위치한 유구 초염기성암은 첨정석 감람암으로, 경계부를 따라 사문석화가 강하게 진행되어 있다. 사문석화작용으로 감람석은 안티고라이트 및 크리소타일로, 니켈 황화광물인 펜틀란다이트는 밀러라이트 및 어웨루이트로 변질되었다. 사문석은 일부 강한 엽리를보이며, 초염기성암 경계 및 유구편마암 면구조와 주로 평행하게 발달한다. 이는 초염기성암의 융기 과정 동안 편마암의 변성작용으로부터 공급받은 열수가 단층 경계를 따라 침투하여 사문석화된 것으로 해석된다. 유구 초염기성암의 기원은 심해저 페리도타이트이며 약 5~18% 정도의 부분 용융을 겪은 잔여물로 해석된다. 부화된 경희토류원소 및 Eu는 맨틀이 2차적인 교대변성작용을 겪었음을 암시한다. 이러한 지화학 결과는유구 감람암의 형성이 중생대 초기 북중국판과 남중국판의 대륙 충돌과 관련 있음을 시사한다. 유구 초염기성암 내 니켈은 0.17~0.21%로, 상당량이 감람석 및 사문석에 포함된다. 따라서 마그마 기원인 유구 초염기성암의 니켈 회수율을 높이기 위해 황화광물의 선광연구와 더불어 산화광물을 대상으로 하는 침출 연구가 요구된다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1230-1232
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• 2003

This study aims to extract maximum geological information using the ASTER (Advanced Spaceborne Thermal Emission and Reflection radiometer) images of a part of south India. The area chosen for this study is characterized by rock types such as Migmatite, Magnetite Quartzite, Charnockite, Granite, dykes, Granitoid gneiss and Ultramafic rocks, and minerals such as Bauxite, Magnesite, Iron ores, Calcite etc. Advantage was taken of the characteristic reflectance and absorption phenomenon in the VNIR, SWIR and TIR bands for these rocks and minerals, and they were mapped in detail. Image processing methods such as contrast stretching, PC analysis, band ratios and fusion were used in this study. The results of the processing matched with the field details and showed additional details, thus demonstrating the usefulness of ASTER (especially the SWIR bands) data for better geological mapping.

• 한국광물학회지
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• 제2권1호
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• pp.11-17
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• 1989

The kaolin deposits in Hadong-Sancheong area, have been formed by supergene weathering of anorthositic rocks including anorthosite, leucogabbro, and gabbro. Kaolin consists chiefly of halloysite(10$\AA$) and kaolinite with other minerals such as illite, vermiculite, plagioclase, hornblende, quartz amorphous materials(allophane and siica), goethite, and hematite. Goethite and hematite are the major coloring agents of the reddish brown and other colored kaolins. Other common accessory minerals are magnetite, ilmentite, anatase, gibbsite, I/S, C/V, chlorite, lithiophorite, and birnessite. Paragonite, dravite, laumontite, clinozoisite, muscovite, scolecite, stellerite are locally found. Al substitution of Fe in goethite and hematite decreases from the surface zone toward the deeper zone. The kaolin deposits show three horizontal zoning; the upper reddish brown, middle pink, and lower white zones. All the zones are characterized by somewhat different mineralogy. The factors for the formation of kaolin deposits in Hadong-Sancheong area are 1) the presence of anorthositic rocks, 2) the low flat or gentle topography, 3) the favorable climate, and 4) the long-continued preservation of kaolins with-out erosion.

• 자원환경지질
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• 제27권2호
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• pp.131-145
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• 1994

The Daehung and Pyeongan talc mines are located in the Yoogoo area, Chungcheongnam-Do. These deposits occur as the complex vein type in the ultramafic rocks which intruded Precambrian gneiss. The talc ore formed from sepentinitt: originated from ultramafic rocks but some of those from hornblende gneiss. The talcification processes were considered here on the basis of the mineral assemblages, paragenesis, and geochemistry. It appears that there are five processes in talcification ; serpentine$\rightarrow$talc, phlogopite$\rightarrow$chlorite$\rightarrow$talc, phlogopite$\rightarrow$talc, hornblende$\rightarrow$chlorite$\rightarrow$talc, and hornblende$\rightarrow$talc. Among them, the most dominant alteration path is serpentine to talc in these deposits. EPMA data suggest that there might be interstratified minerals were in between parent mineral and talc such as serpentine and talc, and phlogopite and talc. It can be found that tremolite exists in between the inner and outer most part of talcified serpentinite blocks coated with phlogopite. Some of tremolites has been altered to talc. The quartz veins and carbonate minerals were found in the talc ore zone. It indicates that the hydrothermal solution played an important role in talcification. The hydrothermal alteration occured after sepentinization. Ore zones can be divided into two zones; talc-serpentine zone preserving a pseudormorph of olivine (mesh texture) and talc-phlogopite zone showing talcification from phlogopite directly or through chlorite. It can be concluded that the formation of major talc ore body was due to talcification of serpentinite and phlogopite by hydrothermal solution. A nature of hydrothermal solution was relatively pure water at the beginning of serpentinization, and was getting richer in silica composition. There was a large amount influx of K and AI with hydrothermal solution in the later stage, and increased $P_{CO_{2}}$ also. It suggests that phlogopite formed in later stages as a secondary mineral. So, the major part of the talc ore body was formed from one parents rocks, serpentinite originated from ultramafic rocks, by hydrothermal solutions at several times.

• Geosciences Journal
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• 제22권6호
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• pp.1001-1013
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• 2018

A new type of uranium occurrence in Korea was identified in pegmatitic and hydrothermally altered granite in the Daejeon area. The U-bearing parts typically include muscovite, pink-feldspar and sericite as alteration minerals. In this study, the geochemical characteristics and alteration age of the granitic rocks were examined to provide evidence for hydrothermally-enriched uranium. The K-Ar ages of muscovite coexisting with U-bearing minerals were determined as 123 and 128 Ma. The U-bearing rocks have relatively low ($CaO+Na_2O$), high $K_2O$ contents, and high alteration index values by major element geochemistry. The trace element geochemistry shows that the uraniferous rocks have significantly low Th/U ratios and strongly differentiated features. The rare earth element patterns indicate that the uraniferous rocks have a low total REE and LREE contents with depletion of Eu. Considering the geochemical variation of the granitic rock major, trace and rare earth elements, it can be concluded that uranium enrichment in pegmatites and altered granite should be genetically related to post-magmatic hydrothermal alteration of K-metasomatism after emplacement of the two-mica granite. This is the first report for geochemical characteristics of Mesozoic granite-related U-occurrences in South Korea. This study will help further research for uranium deposits with similarities in geological setting, mineralogy and age data between South China and Korea, and can also be expected to help solve the source problems related to high uranium concentrations in some groundwater occurring in the granitic terrane.

• 자원환경지질
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• 제32권5호
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• pp.455-468
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• 1999

Carbonated mineral waters fo $Ca(Mg)-HCO_3$ type spring out fissure of Jurassic granite in the valley floor of the Chungsong area. The water has been long as a Dalki medicinal water because of its unique therapeutic effect against clacium deficit, stomach and skin troubles, ect. The water has a high $CO_2$ concentration ($P_{CO_2}$=0.51~1.12atm) and exhibits strong pH buffering (5.9~6.26) by $H_2CO_3/HCO_3$ couple. Electrical conductivity ranges from 1,900 to 3100 $\mu$S/cm. Environmental isotopic data $(^{2}H/^{1}H, ^{18}O/^{16}O \;and \;^3H)$ indicates that the water is of meteoric origin recharged in the Cretaceous sedimetary strata distributed in upper part of the catchment area at least before 1950s, The high $P_{co_2}$ and carbon isotope data (${\delta}^{13}C=-3\sim-0.2\textperthousand$) suggest that the potential source of carbonated mineral water was originated in deep-seated $CO_2$ as wel as aboundant carbonate minerals of sedimentary desimetary rocks. The major source minerals of the dissoved species in the carbonated mineral water appear to be carbonate minerals, albite and K-feld-spar in sedimentrary rocks.

• 대한화학회지
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• 제5권1호
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• pp.26-28
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• 1961

Microgram quantities of thallirum in meteorites, rocks, minerals, alloys and biological samples have been analyzed by rapid neutron activation analysis. A l0-minute radiochemical separation procedure coupled with a gas-flow proportional detector for 4.2-minute half life measurement and a gamma or beta scintillation detector placed in close proximity to the sample permitted detection of the 4.2-min Tl206. Samples were irradiated for 10-minutes at a thermal neutron flux of approximately $0.95{\times}10^{11}$ neutron-$cm^{-2}-sec^{-1}.$ The low limits of detection was about $10^{-7}$ gm of thallium.

• 지질공학
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• 제4권3호
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• pp.269-281
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• 1994

경상북도 경주군 추령터널 축조공사장 암석의 물성과 풍화특성을 밝히기 위한 연구가 수행되었다. 암석의 종류, 구성성분 및 조직의 특성을 알기 위하여 현미경 관찰 및 X선 회절분석을 실시 하였으며, 또한 현장탄성파속도 측정, 시험편에 대한 실험실내에서의 탄성파 전파속도 및 일축압축강도 시험을 실시하였다. 연구지역의 암석은 화산쇄설암인 응회암으로서, 점토광물을 바탕으로 하여 석영, 장석 등의 결정들과 화산암편, 셰일편 등의 암편들로 구성되어 있다. 풍호를 받지 않은 응회암은 평균 압축강도가 약 $443kg/\textrm{cm}^2$, 평균 탄성파속도가 약 3680m/sec인 연암이며, 자갈모양으로 박혀 있는 안산암은 평균 압축강도가 약 $2500kg/\textrm{cm}^2$, 평균 탄성파속도가 약 4340m/sec인 경암으로 판명되었다. 실험실 시편과 현지의 암반에 대한 탄성파 전파속도는 압축강도와 비교적 높은 상관성을 보이면서 비례하는 양상을 보인다. 한편, 실험실 시편에서의 탄성파 속도는 현지 암반보다 약 1.5km/sec 높은 현상을 보이는데, 이는 현지암반에서의 절리, 파쇄대 및 수분으 존재 등에 의하여 탄성파 전파속도가 저하된 현상으로 해석된다. 응회암은 바탄물질과 셰일편에 50% 이상의 점토광물을 함유하고 있어 자연환경에 노출시 쉽게 수분을 흡수하는 특성을 갖는다. 따라서 연구지역의 암석은 풍화되기 전에는 보통암 이상의 강도를 보이나 대기중에 노출되면 다른 암석에 비하여 쉽게 풍화를 받는 특성을 갖는다.

• 한국문화재보존과학회:학술대회논문집
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• 한국문화재보존과학회 2004년도 제20회 발표논문집
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• pp.92-100
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• 2004

The host rocks of brick-shaped stone pagoda in the Bunhwangsa temple are lots of kinds andesitic rocks, which has gone through mechanical and chemical weathering. As the overall observation, the pagoda is serious damages by air pollutants, and the northeast parts show the much advanced state of turning white, while the southeast parts are heavily cracked in the materials. The rocks of brick-shaped pagoda body are in a relatively stable condition of weathering and damage except for the abrasion and cracks of the corners. The rocks of the pagoda roof suffer from more symptoms including multiple peel-offs, exfoliation, cracks forming round lines, and falling off stone pieces. The pagoda roof rocks are dominated by the thriving leafy lichens and mosses, especially, there are higher plants (selaginella involvens, dandelions) taking root actively between the brick stones and content mortar. There are even light gray precipitates like stalactites between the rocks of the body, In particular, the 1st and 2nd floor in the east side and the body parts in the north side are the most serious. Their major minerals are calcite, gypsum and clay minerals. The rocks of the stylobate and the tabernacle in all the four directions are composed mainly of granitic rocks. The materials consisting of the tabernacles show the severe splits and distortion, which causes the structural instability. The stylobate rocks are heavily contaminated by some weeds with the often marks of inorganic contamination by secondary hydroxides. The central part of the east stylobate has been sinking, while that of the 1st floor west stylobate is protruded nesting a line of cracks. Accordingly, the inside of the tabernacle is always humid with the constant introduction of rainwater. The stone lion standing in the southeast and northeast side are alkali granite, while that in the southwest and northwest lithic tuff. Each of the stone lion also coated with various colored lichens, mosses, algae, bacteria and bryophyte. The external materials of the pagoda have deteriorated the functions of the rocks and made the loss, falling off, and biological contamination even worse due to the surface weathering. Thus it's urgent to come up with scientific restoration and conservation measures through clinical tests.

• 한국토양비료학회지
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• 제6권4호
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• pp.253-255
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• 1973

Microscopic method was compared with X-ray diflraction analysis for the identification of rockforming minerals using 11 main rock samples in Korea. 1. There was no difference between X-ray diffraction analysis and microscopic one in major minerals, but some accessary minerals. 2. The rock-forming minerals of main rocks presented in this study occured almost in crystalline state so that they could be easily identified by X-ray analysis alone.