• Journal of the Mineralogical Society of Korea
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• v.23 no.1
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• pp.93-98
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• 2010

• Economic and Environmental Geology
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• v.25 no.3
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• pp.283-296
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• 1992

The Keumryeong deposits is a low grade copper deposits in which copper minerals form disseminated grains and thin veinlets in felsic volcanics seem to be dacite. Alteration of the volcanics consists mainly pervasive propylitization and silicification. Potassic alteration characterized by biotite developed locally adjacent to southwestern contact of granodiorite body. Principal sulfide minerals in altered zone are mainly pyrite and lesser chalcopyrite. Chalcopyrite content in potassic zone is relatively higher than that of surrounding propylitized zone. Pyrite and chalcopyrite accompanies magnetite, molybdenite, sphalerite, pyrrhotite, arsenopyrite, pentlandite, marcasite, hematite, ilmenite, rutile, bismuthinite and native Bi as disseminations, veinlets and knots. Granodiorite body is propylitized and contains veinlets of pyrite, chalcopyrite and molybdenite. Fluid inclusions in sulfide-bearing quartz veinlets and quartz grains of felsic volcanics and granodiorite in altered zone consist of liquid-rich, vapor-rich, $CO_2-bearing$ and halite-bearing inclusions. These four types of inclusion intimately associated on a microscopic scale and indicate condensing or boiling of ore fluid during mineralization. Homogenization temperature of coexisting fluid inclusions are mostly in the range of 350 to $450^{\circ}C$. High salinity fluid contains 28.6 to 48.4 weight percent NaCI equivalent and moderate salinity fluid cotains 0.5 to 12.5 weight percent NaCl equivalent. Pressure estimated from $CO_2$ mole fraction of $CO_2-bearing$ inclusion range 160 to 375 bars. The Kigu copper deposits is a fissure filling copper vein developed 500 m south from the Keumryong deposits. Mineralogy and fluid inclusion data of the Kigu deposits are similar to that of the Keumryeong deposits. Homogenization temperature of fluid inclusions from the Kigu deposits are reasonable agreement with temperature estimated from sulfidation curve of cubanite-chalcopyrite-pyrite-pyrrhotite and pyrite-pyrrhotite mineral assemblages. Not only mineral occurrence and wall rock alteration in the Keumryeong deposits but also fluid inclusion data such as temperature, salinity, pressure and boiling evidences are similar to those of porphyry copper deposits.

• Economic and Environmental Geology
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• v.32 no.3
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• pp.217-225
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• 1999

Nine cauldrons have been recognized in the PVD (Pusan- Taegu Volcano-tectonic Depression) zone covering an area of nearly 7,000 $km^{2}$. They form characteristic landscape features with various mountains in the southeastern Kyongsang basin. Economically important ore deposits are also developed either in the ring fracture zone or the central pluton within the resurgent cauldrons or in the marginal area of the PVD, suggesting that these cauldrons played a major role in the distribution of ore deposits in the southeastern Kyongsang basin. Furthermore, the cauldron subsidences were more frequent with the more felsic volcano-plutonic complex, possibly indicating that the amounts of water and volatile components also acted as a controlling factor to cause the caldera subsidence and to concentrate the ore-forming elements in economic concentrations. The review of the relationship and variations of ore mineralization and cauldron subsidence is rather sketchy, but it provides a skeleton to carry out more detailed and quantitative studies related to temporal and spatial relationships between each cauldron subsidence accompanying its own ore mineralization. In the southeastern Kyongsang basin, additional calderas and associated ore deposits undoubtedly can be discovered through future detailed studies. The concept that cauldron subsidence are an important control for the formation of ore deposits will appear to be vindicated.

• 한국정보컨버전스학회:학술대회논문집
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• 2008.06a
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• pp.99-102
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• 2008

Mineralogical studies of ore and alteration minerals have been conducted for the Hugo Dummett porphyry copper deposit. The Hugo Dummett porphyry copper gold deposit is located in the South Gobi region, Mongolia and currently being explored. This deposit divided into the Cu-rich Hugo Dummett South and the Cu-Au-rich Hugo Dummett North deposits. The Hugo Dummett deposits contain 1.08% copper(1.16 billion tonnes in total) and 0.23 g/t gold(Oyunchimeg et al., 2006). Copper-gold mineralization at these deposit are centered on a high-grade copper(typically>2.5%) and gold(0.5-2 g/t) zone of intense quartz stockwork veining. The high grade copper and gold zone is mainly within the Late Devonian quartz monzodiorite intrusions and augite basalt, also locally occurs in dacitic rocks. Intense quartz veining forms a lens up to 100 m wide hosted by augite basalt and partly by quartz monzodiorite. Although many explorations have been carried out, only a few scientific works were done in the Oyu Tolgoi mining area. Therefore the nature of copper-gold mineralization and orgin of the deposit is not fully understood. Copper-gold mineralization in the Hugo Dummett deposits occurs in dominantly quartz monzodiorite and minor augite basalt, dacitic rocks and locally biotite granodiorite. Chalcopyrite, pyrite, bornite, molybdenite, tennantite, tetrahedrite, enargite, sphalerite, chalcocite, covellite, eugenite, galena and gold occur as main ore minerals in the Hugo Dummett North and South deposits. These sulfides occur as: (1) a vague vein-like trail 1-3cm long and 2-3 mm wide, (2) minute, discontinuous cracks within quartz(micron scales), and (3) irregular blebs/spots(micron scales)and (4) disseminated within the sericite and plagioclase, commonly concentrated in the quartz. Sulfide minerals commonly display as a replacement, intergrown and minor exsolution texture in the both of the Hugo Dummet deposits.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.231-236
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• 2007

Electrical resistivity, self-potential and time-domain induced polarization methods were conducted for study of electrical responses on vein-type sulfides ore, which is intruding limestone and dolomite of Ordovician, of Geumpung mine located in Dojeon-ri, Susan-myeon, Jecheon-si, Chungbuk. Sulfides bearing chalcopyrite, pyrrhotite and galena etc. are deposited in disseminated or vein-type. Good result that resistivity and self-potential surveys detect high grade-estimated mineralized zone located in upper part of existing low grade ore zone is acquisited and is to some extent consistent with induced polarization. Furthmore, a new mineralization zone directing EW is detected.

• Journal of the Mineralogical Society of Korea
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• v.29 no.1
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• pp.23-34
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• 2016

Tsogttsetsii area, an intrusive complex associated with Cu porphyry mineralization, is located in the Gurvansaikhan island arc terrane of the Central Asian Orogenic belt, Southern Mongolia. We performed a reconnaissance survey in Tsogttsetsii area. Cu mineralization in Tsogttsetsii area is porphyry Cu type related with alkali granite intruded in Permian. Mineralogical and textural properties of the ores and associated minerals were analyzed using X-ray diffraction, thin section petrography, and Scanning electron microscopy-Energy dispersive spectroscopy (SEM-EDS). Ore minerals identified in polarizing microscope are magnetite, pyrite and bornite. Propylitic alteration zone occurs broadly in the area where malachite occurrences are shown to be spread intensively in alkali granite area. Quartz, sericite, chlorite and epidote were observed in the alteration zone samples. As results of XRD and SEM-EDS analysis, samples of copper oxides were composed mainly of malachite, cuprite and small amounts of quartz. Average and maximum Cu contents of samples collected from malachite occurrences area are 759 ppm and 6190 ppm, respectively. The characteristics of mineralization in Tsogttsetsii area is similar to Oyu Tolgoi Cu-Au (Mo) deposit and Tsagaan Suvarga Cu-Mo deposit which are 56 km south and 120 km northeast from Tsogttsetsii area, respectively. Characteristics of the study area, such as the geology, tectonic environment, lithology, mineralization, and alterations of the rocks within the survey area, resemble the characteristics of other porphyry deposits. Therefore further exploration including Induced Polarization (IP) survey for identifying subsurface orebody is required.

• Journal of the Mineralogical Society of Korea
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• v.16 no.3
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• pp.265-280
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• 2003

The Mugeuk mineralized area that associated with the pull-apart type Cretaceous Eumseong basin is composed of several gold-silver vein deposits that are emplaced in late Cretaceous biotite granite. The gold-silver deposits in the area show various hydrothermal alteration zones as well as Au/Ag ratios and ore mineralogy. The Geumbong mine showing relatively high gold fineness is composed of multiple veins and show alteration pattern; vein \longrightarrow phyllic \longrightarrow subphyllic \longrightarrow propylitic \longrightarrow subpropylitic zone. In contrast, The Taegeuk mines show the low fineness values, in far southern part are characterized by increasing tendency of simple and/or stockwork veins. The deposit displays alteration pattern; vein \longrightarrow propylitic \longrightarrow subpropylitic zone. Variations of alteration zone with depth show that phyllic zone are dominant in deeper level and propylitic zone sporadically overlapped by argillic zone are dominant in shallow level. The differences of alteration pattern between the gold-silver deposits are reflect the evolution of the hydrothermal fluids; the ore-forming fluids of the Geumbong mine are at relatively high temperature and salinity and highly-evolved meteoric water, developing phyllic zone, the Taegeuk mine containing greater amounts of less-evolved meteoric waters shows relatively low temperature and salinity in ore-forming fluids, developing propylitic zone. The various physicochemical environment for gold-silver mineralization in the Mugeuk mineralized area is due to proximity from heat source area (Mugeuk mine) to marginal area (Taegeuk mine) in a geothermal field. Therefore, it is suggested that the criteria for project exploration in the area are to focus on the area proximal to heat source and phyllic zone.

• Economic and Environmental Geology
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• v.44 no.2
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• pp.109-122
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• 2011

The major Mo deposits in South Korea were formed during the Jurassic Daebo orogeny, the Late Cretaceous and the Tertiary post-orogenic igneous activities, and are characterized by a variety of genetic types such as pegmatite, greisen, skarn, porphyry and vein types. The Jangsu mine is a pegmatite-style deposit which is genetically related to the Jurassic ilmenite-series two-mica granite with the Mo mineralization age of $159.6{\pm}4.5$ Ma. The Geumseong mine occurs as a skarn/porphyry-style deposit associated with highly fractionated granite. Its age of Mo mineralization within aplitic cupola is about 96.5~l07.5 Ma. The Yeonil mine is a porphyry-style deposit, and the Geumeum mine is a veinlet-style deposit along the fracture zone with their mineralization ages of $58.4{\pm}1.6$ and $54.4{\pm}1.2$ Ma, respectively. The contrasts in the style of Mo mineralization in Korea reflect the different environment of the related magmatism. The Jurassic mineralization, being related to deep-seated granitoids, occurs as a pegmatite-style deposit, whereas the Cretaceous one, being related to subvolcanic granitoids, occurs as skarn/porphyry/vein-type ore deposits. The Tertiary Mo mineralization has a close relationship with the igneous activities associated with the Tertiary basin formation along the east coast, Korean peninsular.

• Economic and Environmental Geology
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• v.11 no.4
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• pp.143-167
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• 1978

The Sangdong tungsten (mostly scheelite) mine is located on the southern limb of a major syncline, the Hambaeg syncline, in a thick sequence of lower Paleozoic sedimentary rocks in the mideastern part of south Korea. Productive scheelite mineralization in Sangdong area is confined to one single formation, the Myobong Slate. Four major ore beds, which have an lateral extension over than 1 km and were not heavily subjected to spatial disturbance, are developed in the Myobong Formation. The original materials of the ore-comprising horizones were probably of either calcareous or silceous sediments. The four ore beds, especially in the case of Main ore bed, display both lateral and vertical zoning. Association quartz-mica-scheelite is predominant in the central, while association hornblende-quartz-diopside-scheelite, diopside-garnet and wollastonite-garnet are developed in this order towards the periphery of the ore beds. Petrologically, two phases of thermometamorphism are recognized. The first phase is represented by the association wollastonite-garnet and diopside-garnet, while the second phase by the association hornblende-quartz-diopside-scheelite and quartz-mica-scheelite. The associations of the second phase do constitute prodctive ore. The high background value of tungsten in the area surrounding the Sangdong mine reveals that the area can be considered a geochemical zone enriched in tungsten. Studies on the trace element patterns were carried out to draw useful criteria for the purpose of future geochemical exploration in the area. The increasing trend of the ratio Rb $({\times}1000)/K_2O$ of the Myobong Slate towards the known mineralization area proved to be indicative for the presence of tungsten mineralization.

• Economic and Environmental Geology
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• v.31 no.5
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• pp.375-388
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• 1998

The purpose of this study is to investigate the ore genesis and occurrence of the Wondong polymetallic mineral deposits. The Pb-Zn, Fe and W-Mo mineralizations are found in skarn zones which formed mainly in or along the fault shear zones with the $N25-40^{\circ}W$ and $N10-50^{\circ}E$ directions, whereas the Cu-Mo mineralization is appeared hydrothermal replacement zone. The skarn minerals consist mainly of garnet and epidote, which were the last alteration phases between pneumatolytic and hydrothermal stages. The mineral paragenesis toward the late stage are as follows: arsenopyrite, scheelite, magnetite, pyrite, pyrrhotite, sphalerite, galena, chalcopyrite and molybdenite. Average ore grades are 0.33 g/t Au, 46.29 g/t Ag, 0.06% Cu, 4.4% Pb, 2.61% Zn and 29.39% Fe in tunnels, and 0.31 % Cu, 0.52% Pb, 6.29% Zn, 29.29% Fe, 0.03% Mo and 0.12% $WO_3$ in drill cores. Fluid inclusion data shows that Type I (liquid-rich), Type II (vapor-rich) and Type III (halite-bearing) inclusions are coexisted and their homogenization temperatures are quite similar. This indicates that boiling conditions have been reached during the mineralization. It is also likely that the ore solutions were evolved through the mixing between magmatic and meteoric waters. Rhyolite and quartz porphyry far the mineralization probably are not responsible of the Wondong polymetallic mineral deposits.