• Economic and Environmental Geology
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• v.50 no.6
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• pp.435-443
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• 2017

The Hanae deposit is located within the Cretaceous Gyeongsang Basin. The Cu-bearing hydrothermal quartz vein formed by narrow open-space filling along fracture in the sedimentary rocks as Jindong Formation. The Hanae Cu-bearing hydrothermal deposit shows a paragenetic sequence of pyrrhotite-pyrite $\rightarrow$ pyrite-chalcopyrite-sphalerite(${\pm}$Bi-bearing tellurides) $\rightarrow$ Ag-bearing telluride mineralization $\rightarrow$ secondary mineralization. Fluid inclusion data indicate that the Hanae Cu-bearing hydrothermal mineralization occurred from dominantly aqueous fluids at temperatures of $400^{\circ}C-200^{\circ}C$. Equilibrium thermodynamic interpretation of the mineral paragenesis and assemblages combined with fluid inclusion data indicate that early main Cu-bearing ore mineralization in the vein starts at about $350^{\circ}C$ which corresponds to sulfur fugacity from about $10^{-9.2}$ to $10^{-8.7}bar$ with oxygen fugacity of about $10^{-32.1}$ to $10^{-29.8}bar$. Late main Cu-bearing ore mineralization in the vein occurs at about $250^{\circ}C$ which corresponds to sulfur fugacity from about $10^{-13.5}$ to $10^{-11.7}bar$ with oxygen fugacity of about $10^{-38.4}$ to $10^{-35.2}bar$. The late Ag-bearing telluride mineralization in the Hanae hydrothermal system occurs at about $200^{\circ}C$ which corresponds to minium Tellirium fugacity value of about $10^{-18}bar$ with sulfur fugacity of about $10^{-14.0}$ to $10^{-10.9}bar$.

• Economic and Environmental Geology
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• v.46 no.1
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• pp.11-19
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• 2013

The Daehwa Mo-W deposit is located within the Gyeonggi massif. Quartz and calcite vein mineralization occurred in the Precambrian gneiss and Jurassic granites. Three main types (Type I: liquid-rich $H_2O$ type, Type II: vapor-rich $H_2O$ type, Type III: $CO_2-H_2O$ type) of fluid inclusions were observed and are classified herein based on their phase relations at room temperature. Within ore shoots, type III fluid inclusions have been classified into four subtypes (type IIIa, IIIb, IIIc and IIId) based on their volume percent of aqueous and carbonaceous ($CO_2$) phase at room temperatures combined with their total homogenization behavior and homogenization behavior of $CO_2$ phase. Homogenization temperatures of primary type I fluid inclusions in the quartz range from $374^{\circ}C$ to $161^{\circ}C$ with salinities between 13.6 and 0.5 equiv. wt.% NaCl. Homogenization temperatures of primary type III fluid inclusions in quartz of main generation, are in the range of $303^{\circ}C$ to $251^{\circ}C$. Clathrate melting temperatures of the type III fluid inclusions were 7.3 to $9.5^{\circ}C$, corresponding to salinities of 5.2 to 1.0 equiv. wt. % NaCl. Melting and homogenization temperatures of $CO_2$ phase of type III fluid inclusions were -57.4 to $-56.6^{\circ}C$ and 29.0 to $30.8^{\circ}C$, respectively. Fluid inclusion data indicate a complex geochemical evolution of hydrothermal fluids. The Daehwa early hydrothermal system is characterized by $H_2O-CO_2$-NaCl fluid at about $400^{\circ}C$. The main mineralization occurred by $CO_2$ immiscibility at temperatures of about 300 to $250^{\circ}C$. At the late base-metal mineralization aqueous fluid formed by mixing with cooler and less saline meteoric groundwater.

• Economic and Environmental Geology
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• v.49 no.6
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• pp.491-504
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• 2016

Jinwon Au-Ag deposit is located in the Uijin gun which is southeast 300 km from Seoul. The deposit area consists of mainly Precambrian Hongjesa granite, which occurs as porphyroblastic texture, medium grain and composed of quartz, feldspar and mica. This deposit consists of four parallel hydrothermal quartz veins that fill NE oriented fractures in Precambrian Hongjesa granite. The grade of quartz veins contain from 3.0 to 21.4 g/t (average 6.4 g/t) gold and from 5.0 to 252.0 g/t (average 117.9 g/t) silver, respectively. They vary from 0.2 m to 0.6 m (average 0.3 m) in thickness and extend to about 200 m in strike length. Quartz veins occur as massive, network, cavity, breccia, crustiform, comb and zonal textures. Wallrock alteration has silicification, sericitization, pyritization and argillitization. The mineralogy of the quartz veins consists of quartz, arsenopyrite, cassiterite, pyrite, sphalerite, chalcopyrite, galena, electrum, tetrahedrite, canfieldite, argentite, Ag-Sb-S mineral, Mn-Fe-O mineral, Pb-O mineral and Pb-P-Cl-O mineral(chloro-pyromorphite). Chemical compositions of minerals from this deposit are as followed; Fe/Fe+Mg of sericite is from 0.32 to 0.71, As content of arsenopyrite ranges from 27.91 to 30.33 atomic %, FeS content of sphalerite range from 9.77 to 16.76 mole %, Ag content of electrum is from 29.42 to 37.41 atomic % and Ag content of tetrahedrite range from 32.17 to 36.53 wt.%, respectively. Baased on mineralogy and chemical compositions of minerals from Jinwon Au-Ag deposit, deposition of minerals was caused by a change in temperature, oxygen fugacity($fO_2$) and sulfur fugacity($fS_2$) from the near neutral hydrothermal fluid evolved by reaction with wallrock.

• Economic and Environmental Geology
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• v.43 no.3
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• pp.235-248
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• 2010

To construct the standard methods for evaluation of physicochemical characteristics of tailings in Korea, specific gravity, paste pH, grain size, mineral compositions and heavy metal concentrations of total 26 tailings from 21 metallic mines were analyzed. Specific gravity of tailings ranged from 2.61 to 4.31 (avg. 3.04), and sand and silt grain were dominant in the tailings. Ranges of paste pH were 2.1-9.5 in tailings (7.1-9.2 at magmatic, skarn and hydrothermal replacement deposits and 2.1-9.5 at hydrothermal vein deposits). Additionally, hydrothermal vein deposits could be reclassified into three categories: (1) paste pH>7.0, (2) 4.0

• Journal of the Mineralogical Society of Korea
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• v.31 no.1
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• pp.57-65
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• 2018

The geology of Hidalgo state in Mexico is formed by a Precambrian metamorphic rock base which discordantly supports a strong Paleozoic sedimentary rock sequence. Triassic-Jurassic and Cretaceous sedimentary rocks overlie the above-mentioned rocks at a discordant angle. These Mesozoic rocks are in turn covered by a Cenozoic structure which is marine at its base. At the top, the structure changes to andesitic and basaltic composition volcanic rocks. And, a great variety of mineral deposits, both metallic and nonmetallic, is present in Hidalgo state. The host rocks of these deposits are also very varied in age from Mesozoic to Tertiary. Mineralization age corresponds to Tertiary in 90% of the area. Hidalgo state occupies as an important place in national silver and manganese production. Main mineral deposits correspond to argentiferous veins hosted in sedimentary rocks. Following in order of importance are lead and zinc, as well as some small iron deposits. There is evidence of tin and molybdenum mineralization, but these deposits have not been exploited because of their low grade and volume. And, Hidalgo state has different types of nonmetallic mineral deposits such as sedimentary, hydrothermal, metamorphic and volcanic origins.

• Geophysics and Geophysical Exploration
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• v.24 no.4
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• pp.202-208
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• 2021

Induced polarization (IP) was first published in a Korean academic journal in 1973, and it was soon applied to coal and metal ore exploration. Then, in universities and research institutes, IP modeling studies using the finite element approach and experimental studies on IP responses for artificial samples were conducted. In the mid-1980s, the spectral IP (SIP) measurement module was introduced to Korea, and physical scale modeling and inversion approaches were developed. Due to the decline of the mineral resource industry, this method was not actively applied. However, the SIP method was not applied In the 1990s, IP exploration was applied in the investigation of hydrothermal deposits of sulfide minerals and bentonite mineralization zones, as well as to areas where the groundwater was contaminated by intruding seawater. In the 2000s, three-dimensional inversion of the IP approach was developed, and high-precision geophysical exploration was required to secure domestic and overseas mineral resources, so SIP experiments on rock samples and approaches for field exploration were developed. The SIP approach was proven useful for the exploration of metal deposits containing sulfide minerals by applying it to explore the mineralization zone of gold-silver deposits in the Haenam region. The IP method is considered to be effective in exploring critical minerals (lithium, cobalt, and nickel) in high-tech industries. It also is expected to be useful for environmental and geotechnical investigations.

• Economic and Environmental Geology
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• v.14 no.1
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• pp.1-25
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• 1981

This paper is a literature review on the following subjects: 1) relationships between porphyry molybdenum and copper systems; 2) hydrothermal environments of molybdenite depositions; 3) genetic significance of molybdenite polyforms; and 4) trace element patterns in molybdenite useful as an exploration guide. The geologic similarities between porphyry molybdenum (e. g. Climax) and porphyry copper (e. g. Bingham) systems exist, and similar techniques can be applied for exploring deposits of either type. Several features suggest that tungsten and tin may form porphyry-like systems (i. e. lowgrade, large tonnage). The clustering of porphyry-like systems in geophysically distinctive batholithic provinces is well documented and provides larger targets for reconnaissance exploration. Geochemical studies suggest that uranium should often occur in close proximity to molybdenum ores in igneous as well as sedimentary environments.

• Economic and Environmental Geology
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• v.46 no.3
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• pp.267-278
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• 2013

The East African Rift System(EARS) is known to be hosted epithermal Au-Ag deposits, and the best-known example is Main Ethiopian Rift Valley(MER) related to Quaternary bimodal volcanism. Large horst-graben system during rifting provides open space for emplacement of bimodal magmas and flow channel of geothermal fluids. In recent, large hydrothermally altered zones(Shala, Langano, and Allalobeda) and hot spring related to deeply circulating geothermal water have been increasing their importance due to new discoveries in MER and Danakil depression. The hot springs in Shala and Allalobeda occur as boiling pool and geyser on the surface, whereas some areas didn't observe them due to decreasing ground water table. The host rocks are altered to quartz, kaolinite, illite, smectite, and chlorite due to interaction with rising geothermal water. The hot springs in MER are neutral to slightly alkaline pH(7.88~8.83) and mostly classified into $HCO_3{^-}$ type geothermal water. They are strongly depleted in Au, and Ag, but show a higher Se concentration of up to 26.7 ppm. In contrast, siliceous altered rocks around hot springs are strongly enriched in Pb(up to 33 ppm, Shala), Zn(up to 313 ppm, Shala), Cu(up to 53.1 ppm, Demaegona), and Mn(up to 0.18 wt%t, Shala). In conclusion, anomalous Se in hot spring water, Pb, Zn, Cu, and Mn in siliceous altered rocks, and new discoveries in MER have been increasing potential for epithermal gold mineralization.

• Economic and Environmental Geology
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• v.3 no.2
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• pp.123-133
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• 1970

위에서 상논(詳論)한것을 요약(要約)하면, 1) 본(本) 지성(地城)을 구성(構成)하는 지질(地質)은 신나통(新羅統)의 퇴적암류(堆積岩類), 이를 관입(貫入)하는 불국사순(佛國寺純)의 화강록암(花崗綠岩) 및 암맥(岩脈)으로 되어 있다. 2) 광구일대(鑛區一帶)의 퇴적암류(堆積岩類)는 원내(原來)의 퇴적상(堆積相)과 화강섬록암(花崗閃綠岩)의 관입등(貫入等)으로 규화(珪化)되 어 규암(珪岩) 또는 규화(珪化)된 혼펠스로 변(變)하여 있다. 3) 지질구조(地質構造)는 단순(單純)한 배사(背斜)를 나타내 며 퇴적암(堆積岩) 및 화강섬록암중(花崗閃綠岩中)에 수(數) sets의 절이(節理)가 발달(發達)하여 이들에 따라 광화작용(鑛化作用)이 이루어졌다. 4) 광상(鑛床)은 퇴적암(堆積岩) 및 화강섬록암중(花崗閃綠岩中)의 열하에 연(沿)하여 배태(胚胎)하며 연(軟)망간광(鑛) 광맥(鑛脈)과 금은광맥(金銀鑛脈)의 2종(種)이 발달(發達)된다. 5) 금은광맥(金銀鑛脈)은 맥폭(脈幅)이 좁고 주향방향(走向方向)의 연장(延長)이 단속(斷續)되 며 분석결과(分析結果) 금(金)은 없고 은(銀)은 23.3g/t 내지(乃至) 913.3g/t 이여서 가행가치(稼行價直)가 없다. 6) 망강광맥(鑛脈)은 수조(數條)있으나 주목(注目)만한 것은 제(第)4갱맥(坑脈)과 제(第)5갱맥(坑脈)으로서, 전자(前者)는 연장(延長) 120m, 평균맥폭(平均脈幅) 0.5m 추정(推定)되며, 평균품위(平均品位)는 Mn 약(約) 17.5%이다. 후자(後者)도 연장(延長) 120m, 평균맥폭(平均脈幅) 0.6m 추정(推定)되며, 평균품위(平均品位)는 15.7%이다. 7) 광맥(鑛脈)은 후화강섬록암시기(後花崗閃綠岩時期)의 열하의 방위(方位)에 지배(支配)받으며, 주향(走向) 및 경사방향(傾斜方向)으로 전변(轉變)한다. 그러나 규암질모암(珪岩質母岩)의 성질(性質)로 보아 광상(鑛床)이 팽대(膨大)하여질 가능성(可能性)은 없다. 8) 망간 및 금은광맥(金銀鑛脈)은 열수광상(熱水鑛床)에 속(屬)한다.

• Economic and Environmental Geology
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• v.12 no.2
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• pp.79-93
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• 1979

Twenty five samples of the scheelite-powellite series from twelve Korean tungsten deposits of various geologic settings were studied mineralogically and geochemically. Variations in the trace-element contents of the scheelite minerals are considered in relation to geologic settings and mineralogic properties. Scheelites from ore deposits developed in similar geologic settings and under similar physicochemical conditions are characterized by specific combinations of trace elements.