• Economic and Environmental Geology
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• v.20 no.4
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• pp.289-303
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• 1987

당(當) 광산(鑛山)은 1936년(年) 금(金), 은(銀) 광종(鑛種)으로 출원(出願)하였다가 1940년(年) 망간을 추가(追加)하여 망간 광산(鑛山)으로 1975년(年)까지 Mn(30~35%) 110,000여(餘)톤을 생산(生産), 국내생산량(國內生産量)의 70%를 점(占)하였고 1976년(年) Mn광상(鑛床) 하부(下部)에 연(鉛), 아연(亞鉛) 유화광(硫化鑛)을 발견(發見), 현재(現在)까지 Pb十Zn=10% 이상(以上) 원광석(原鑛石) 500,000여(餘)톤을 처리(處理), 연정광(鉛精鑛)(Pb : 62%) 37,000여(餘)톤, 아연정광(亞鉛精鑛)(Zn : 46.5%) 37,000여(餘)톤, 유비광정광(硫砒鑛精鑛)(As : 30%) 5,000여(餘)톤을 생산(生産)하였다. 현재(現在) 일처리(日處理) 220톤 선광장(選鑛場)을 일처리(日處理) 400톤 규모(規模)로 증설계획중(增設計劃中)이다. 당(當) 광산(鑛山)에서 현재(現在)까지 시행(施行)한 갱외시추(坑外試錐)는 75개공(個孔) 18,500여(餘)m, 갱내시추(坑內試錐) 750개공(個孔) 40,000여(餘)m 갱도(坑道) 총연장(總延長) 13,000m에 달(達)하며 지표(地表)(623ML)로 부터 수직(垂直) 300m 하부(下部)까지 갱도(坑道)가 개착(開鑿)되어 있다. 당(當) 광산(鑛山)의 지질(地質)은 여러 조사서(調査書)에 의(依)하여 견해(見解) 차이(差異)를 보여주고 있으나 대체(大體)로 다음과 같은 쪽으로 인정되고 있다. 즉(卽) 본지역(本地域) 루층군(累層群)의 층순(層順)을 하위(下位)로 부터 상위(上位)로 향(向)하여 원남층(遠南層)${\rightarrow}$율리통(栗里統)${\rightarrow}$장산규암층(壯山珪岩層)${\rightarrow}$두음리층(斗音里層)${\rightarrow}$장군석회암층(將軍石灰岩層)${\rightarrow}$동수곡층(東水谷層)${\rightarrow}$재산층(才山層)의 순위(順位)로 보며 장산규암층(壯山珪岩層)과 두음리층(斗音里層)을 조선계(朝鮮系)의 양덕통(陽德統)으로, 장군석회암층(將軍石灰岩層)을 대석회암통(大石灰岩統)으로, 동수곡층(東水谷層)과 함탄층(含炭層)인 재산층(才山層)을 평안계(平安系) 지층(地層)으로 대비(對比)한다. 이들은 본지역(本地域) 북(北)쪽에서는 선(先)캠브리아기(紀)의 원남층(遠南層)과 율리통(栗里統)을 불정합(不整合)으로 덮고 남측(南側)에서는 재산층(才山層)과 원남층(遠南層)이 단층접촉(斷層接觸)하고 있다. 이들 지층(地層)의 주향(走向)은 $N60^{\circ}{\sim}80^{\circ}W$, $N60^{\circ}{\sim}80^{\circ}E$이며 경사(傾斜)는 대체(大體)로 $50^{\circ}{\sim}80^{\circ}N$이며 전체적(全體的)으로 역전(逆轉)된 층서(層序)를 보여주는 바 지질구조(地質構造)에 있어서 단사구조(單斜構造)인지 등사(等斜)습곡의 향사(向斜), 또는 등사(等斜)습곡이 배사구조(背斜構造)인지 아직 밝혀지지 않고 있다. 화성암체(火成岩體)는 본지역(本地域) 서측(西側)에 쥬라기(紀) 춘양화강암(春陽花崗岩)이 불규칙(不規則)한 실입(實入) 접촉면(接觸面)을 보여주며 시대미상(時代未詳)(백악기(白堊紀)?)의 거정화강암(巨晶花崗岩), 반화강암(半花崗岩)이 소암주상(小岩株狀)으로 몇 곳 실입(實入)하고 산성(酸性)~중성(中性)의 맥암(脈岩)과 염기성(鹽基性) 안산암질암(安山岩質岩)이 실입(實入)해 있다. 광상(鑛床)은 장군석회암층(將軍石灰岩層)에 배태(胚胎)되어 있는 열수교대(熱水交代) 연(鉛), 아연(亞鉛), 은등(銀等)의 혼합(混合) 유화광상(硫化鑛床)으로 다량(多量)의 Mn분(分)을 수반(隨伴)하며 지표부(地表部)에 Mn광상(鑛床)을 형성(形成)하고 있다. 광상(鑛床)의 형태(形態)는 괴상(塊狀), 각력(角礫)pipe상(狀), 맥상(脈狀)으로 나타난다. 광상(鑛床)의 성인(成因)과 생성시기(生成時期)에 대(對)하여 많은 논란(論難)이 있다. 즉(卽) 열수교대(熱水交代)냐, 접촉교대(接觸交代)냐, 동시퇴적기원(同時堆積起源)이냐, 또는 생성시기(生成時期)가 쥬라기(紀)인지 백악기(白堊紀)인지에 대해 이론(異論)이 있다. 본지역(本地域) 광상(鑛床)은 남본(南本), 100우(右), 북(北), 유비철(硫砒鐵), 동(東), 서(西), 재남(才南), 재동(才東), 110호(號) 등(等)이 지표(地表) Mn로두광화대(露頭鑛化帶)와 관련(關聯) 명명(命名)된 바 전(前)4자(者)는 하부(下部)에서 유화광상(硫化鑛床)이 확인(確認)되었으나 나머지 후자(後者)에서는 아직 하부(下部)에 유화광상(硫化鑛床)이 확인(確認)되지 않고 있으며 남본광상(南本鑛床)으로 부터 남동(南東) 300여(餘)m 지점에 장군석회암층(將軍石灰岩層)과 동수곡층(東水谷層) 경계부(境界部)에 Fe 55~60% 자철광상(磁鐵鑛床)이 확인(確認)된 바 신례미(新禮美) 자철광상(磁鐵鑛床)과 유사성(類似性)이 있는 것 같아 흥미(興味)롭다. 당(當) 광산(鑛山)의 현재(現在)까지의 탐광(探鑛)은 남본광상(南本鑛床) 지표로두(地表露頭)(Mn) 하부(下部)에서 확인(確認)된 연(鉛), 아연(亞鉛), 은(銀) 유화광체(硫化鑛體) 하부(下部)와 전탐(電探)에 의(依)해 확인(確認)된 북광체(北鑛體), 갱도접근중(坑道接近中)에 확인(確認)된 100우광체(右鑛體), 유비철광체(硫砒鐵鑛體) 등(等)의 하부(下部) 탐광(探鑛)을 주(主)로 하고 지표(地表) Mn로두(露頭) 하부(下部)에 대(對)한 시추탐광(試錐探鑛0을 병행(竝行)하고 있으며 시추(試錐)에 의(依)해서 지표(地表)로 부터 790m 하부(下部)(해발(海拔) 200ML)까지 광화대(鑛化帶)가 확인(確認)되었다. 향후(向後) 탐광방침(探鑛方針)을 확고(確固)히 수립(樹立)하기 위(爲)하여는 광상(鑛床)의 성인구명(成因究明)은 물론(勿論) 광상(鑛床)의 배태조건(胚胎條件)에 있어 지질구조규제(地質構造規制)와 화강암(花崗岩)의 실입상(實入狀)과의 관계(關係), 광액(鑛液)의 통로(通路)에 대(對)한 지질구조(地質構造), 모암(母岩)의 화학(化學) 물리적(物理的) 특성(特性)에 대(對)한 연구(硏究) 검토(檢討)가 었어야 하겠다.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.259-273
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• 1992

The Seongsan mine is one of the largest dickite deposits in the southwestern part of the Korean Peninsula. The main constithent minerals of the ore are dickite and quartz with accessory alunite, kaolinite and sericite. The geology around the Seongsan mine consists mainly of the late Cretaceous felsic volcanic rocks. In the studied area, these rocks make a synclinal structure with an axis of E-W direction plunging to the east. Most of the felsic volcanic rocks have undergone extensive hydrothermal alteration. The hydrothermally altered rocks can be classified into the following zones: Dickite, Dickite-Quartz, Quartz, Sericite, Albite and Chlorite zones, from the center to the margin of the alteration mass. Such zonal arrangement of altered rocks suggests that the country rocks, most of which are upper part of the rhyolite and welded tuff, were altered by strongly acid hydrothermal solutions. It is reasonable to consider that initial gas and solution containing $H_2S$ and other compounds were oxidized near the surface, and formed hydrothermal sulfuric acid solutions. The mineralogical and chemical changes of the altered rocks were investigated using various methods, and chemical composition of fifty-six samples of the altered rocks were obtained by wet chemical analysis and X.R.F. methods. On the basis of these analyses, it was found that some components such as $SiO_2$, $Al_2O_3$, $Fe_2O_3$, CaO, MgO, $K_2O$, $Na_2O$ and $TiO_2$ were mobilized considerably from the original rocks. The formation temperature of the deposits was estimated as higher than $200^{\circ}C$ from fluid inclusion study of samples taken from the Quartz zone. On the basis of the chemical composition data on rocks and minerals and estimated temperatures, the hydrothermal solutions responsible for the formation of the Seongsan dickite deposits were estimated to have the composition: $m_{K^+}=0.003$, $m_{Na^+}=0.097$, $m_{SiO_2(aq.)}=0.008$ and pH=5.0, here "m" represents the molality (mole/kg $H_2O$).

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.337-346
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• 2006

The Jinwon Pb-Zn deposit is located within the Precambrian Youngnam Massif. Ore mineralization at the Jinwon deposit occurred in quartz veins that filled fractures in the Hongjesa granite. Mineral paragenesis can be divided into two stages(stage I and II). Stage I, at which the precipitation of major ore minerals occurred, is further divided into two substages with paragenetic time based on minor fractures and discernible mineral assemblages: substage la is characterized by pyrite, arsenopyrite ($28.4{\sim}30.3$ atomic % As), pyrrhotite, magnetite, chalcopyrite, sphalerite ($13.1{\sim}16.0$ mole % FeS) assemblages; substage $I_a$ is represented by main precipitation of Zn, Pb minerals and is characterized by sphalerite ($15.1{\sim}19.0$ mole % FeS), galena, miargyrite, argentile assemblages. Stage II is economically barren quartz veins. Thermodynamics study is used to estimate changes in chemical conditions of the hydrothermal fluids during stage I mineralization, the main ore deposition period at the Jinwon hydrothermal system. The range of estimated sulfur fugacity ($fs_2$) was from $10^{-7}\;to\;10^{-16}$ atm and oxygen fugacity ($fo_2$) was in the range of $10^{-32.8}{\sim}10^{-38.5} atm$. Carbon dioxide fugacity ($fco_2$) was $<10^{-0.6} atm$.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.287-295
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• 2007

A mineral potential map showing the distributions of potential areas for exploration of undiscovered mineral deposits is a kind of predictive thematic maps. For any predictive thematic maps to show reasonably significant prediction results, validation information on prediction capability should be provided in addition to spatial locations of high potential areas. The objective of this paper is to apply prediction rate curves to the estimation of prediction probability of future discovery. A case study for Au-Ag mineral potential mapping using geochemical data sets is carried out to illustrate procedures for estimating prediction probability and for an interpretation. Through the case study, quantitative information including prediction rates and probability obtained by prediction rate curves was found to be very important for the interpretation of prediction results. It is expected that such quantitative validation information would be effectively used as basic information for cost analysis of exploration and environmental impact assessment.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.347-353
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• 2005

The geology of the Tumbang Lapan area consists of Permian to Carboniferous metamorphic rocks, Cretaceous granitic rocks, and Permian to Tertiary sedimentary and volcanic rocks. Three faults are developed in surveyed area, and are functioned as channels of the hydrothermal solution which farmed quartz veins within tuff3. In the mineralized area, argillic and propylitic alterations are dominant. Argillic altered rocks show the alteration mineral assemblages of kaolinte+sericite+quartz+chlorite+pyrite. Mineral association in propylitic alteration is chlorite+epidote+feldspar+quartz+pyrite+ magnetite. Vein type, fracture filling, stockwork are observed in survey area. As a result of analysis of samples from quartz veins and altered rocks, some mineralized rocks showed $0.01\~4.6g/t$ of gold.

• Economic and Environmental Geology
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• v.22 no.1
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• pp.1-16
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• 1989

Electrum-galena-sphalerite mineralization of the Yangpyeong-Weonju Au-Ag area was deposited in three stages of quartz and calcite veins which fill fault breccia zones. Fluid inclusion and stable isotope data show that ore mineralization was deposited at temperatures between $260^{\circ}C$ and $180^{\circ}C$ from fluids with salinities between 8.9 and 2.9 equivalent weight percent NaCl. Evidence of boiling indicates pressures of <50 bars, corresponding to depths of 220 to 550 m, respectively, assuming lithostatic and hydrostatic loads. Au-Ag deposition was likely a result of bolling coupled with cooling. Within stages I and II there is an apparent increase in ${\delta}^{34}S$ values of $H_2S$ with paragenetic time ; early -1.4~2.7‰ to later 6.6-9.2‰. The progressively heavier $H_2S$ values can be generated through isotopic re-equilibration in the ore fluid following removal of $H_2S$ by boiling or precipitation of sulfides. Measured and calculated hydrogen and oxygen isotope values of ore-forming fluids suggest meteoric water dominance, approaching unexchanged meteoric water values. Comparison of these values with those of other Korean Au-Ag deposits reveals a relationship between depth and degree of water-rock interaction. All investigated Korean Jurassic and Cretaceous gold-silver-bearing deposits have fluids which are dominantly evolved, meteoric water, but on1y deeper systems (${\geq}1.25km$) are exclusively gold-rich.

• Economic and Environmental Geology
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• v.28 no.6
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• pp.587-597
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• 1995

Two distinct precious-metal mineralizations actively occur at central and southeastern Korea which display consistent relationships among geologic, geochemical and genetic environments. A large number of preciousmetal vein deposits in the central Korea occur in or near Mesozoic granite batholiths elongated in a NE-SW direction. Whereas, gold and/or silver deposits in the southeastern Korea occur within Cretaceous volcanic and sedimentary rocks. However, most of the precious-metal deposits in the southeastern Korea show characteristics of the silver-rich deposits than the gold-rich deposits in the central Korea. Two epochs of main igneous activities are recognized: a) Jurassic Daebo igneous activity between 121 and 183 Ma, and b) Cretaceous Bulgugsa igneous activity between 60 and 110 Ma. Precious-metal mineralization took place between 158 and 71 Ma, coinciding with portions of the two magmatic activities. Contrasts in the style of mineralization, together with radiometric age data and differences in geologic settings reflect the genetically variable natures of hydrothermal activities from middle Jurassic to late Cretaceous time. The compilation and re-evaluation of these data suggest that the genetic types of hydrothermal precious-metal vein deposits in the central and southeastern Korea varied with time. The Jurassic and early Cretaceous mineralizations are characterized by the Au-dominant type, but tend to change to the Au-Ag and/or Ag-dominant types at late Cretaceous. The Jurassic Au-dominant deposits commonly show several characteristics; prominent associations with pegmatites, simple massive vein morphologies, high fmeness values in ore-concentrating parts, and a distinctively simple ore mineralogy such as Fe-rich sphalerite, galena, chalcopyrite, Au-rich electrum, pyrrhotite and/or pyrite. The Cretaceous precious-metal deposits are generally characterized by some- features such as complex vein morphologies, low to medium fmeness values in the ore concentrates, and abundance of ore minerals including Ag sulfosalts, Ag sulfides, Ag tellurides and native silver. Mineralogical and fluid inclusion studies indicate that the Jurassic Au-dominant deposits in the central area were formed at the high temperature (about $300^{\circ}$ to $500^{\circ}C$) and pressure (about 4 to 5 kbars), whereas mineralizations of the Cretaceous Au-Ag and Ag-dominant deposits were occurred at the low temperature (about $200^{\circ}$ to $350^{\circ}C$) and pressure (<0.5 kbars) from the ore fluids containing more amounts of less-evolved meteoric waters.

• Economic and Environmental Geology
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• v.24 no.1
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• pp.9-20
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• 1991

Gusi pyrophyllite deposit is located in the Haenam volcanic field in the southwestern part of the Korea Peninsula. This area is known for the occurrences of pyrophyllite, alunite and dickite. This volcanic field is composed of andesite, rhyolite and pyroclastic rocks of late Cretaceous age The pyroclastic rocks are hydrothermally altered to pyrophyllite and kaolin minerals forming the Gusi deposits. The hydrothermally altered rock can be classified into the following zones on the basis of their mineral assemblages: quartz, pyrophyllite, dickite and illite-smectite zones, from the centre to the margins of the alteration mass. Such mineral assemblages indicate that the country rocks, most of which are the lower Jagguri Tuff, were altered by strongly acidic hydrothermal solutions with high aqueous silica and potassium activity and that the formation temperature of pyrophyllite is higher than $265^{\circ}C$. The mechanism of the hydrothermal alteration is considered to be related to felsic magmatism.

• Journal of the Mineralogical Society of Korea
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• v.18 no.3 s.45
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• pp.227-236
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• 2005

Hydrothermal tourmaline occurs as aggregates or dissemination in the diaspore nodule from an aluminum-rich clay deposit, Milyang, southeastern Korea. Most crystals of tourmaline show complex textures that are finely zoned. The fine-scale chemical zonation of hydrothermal tourmaline reflects the fluctuation conditions that would be expected from fluid mixing in open systems. Oscillatory chemical zoning in tourmaline formed and showed similar patterns, regardless of its crystallographic directions. Mg was enriched in the early stage of crystal growth while Fe was enriched in the later stage, with fluctuations of the ratio of Fe to Mg. Chemical analysis, BSE images, and X-ray compositional maps confirm that the oscillatory Boning in tourmaline is exclusively controlled by the variations of Fe and Mg contents, but the contribution of boron to the zonation is insignificant. The fact that tourmaline altered to diaspore and dickite indicates that tourmaline was unstable with respect to these aluminous minerals as the B, Fe, and Mg activities decreased. Therefore, the aluminum activity may control the stability of tourmaline in the hydrothermal system.

• Journal of the Korean earth science society
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• v.29 no.7
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• pp.551-558
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• 2008

The Soowang deposits occur in the quartz veins that were filled fissures in the middle Cretaceous porphyritic granite and/or the Precambrian Sobaegsan gneiss complex. Paragenetic studies suggest that the vein filling can be divided into four identifiable stages. Sphalerites were deposited by the cooling fluids at stages I, II, and III. The results of microscopic observation and EPMA analysis suggest that the chalcopyrite dots and disease in sphalerite are replacement products by later hydrothermal solution at the early stage III. The inferred processes of chalcopyrite disease are as follows: (1) Fe enrichment to the margins and along the cracks of the Fe-poor sphalerite by Fe-rich solution, (2) Formation of chalcopyrite dots in the Fe-enriched sphalerite formed at the stage II, and Fe reduction of sphalerite near the chalcopyrite dots by Cu-bearing solution, (3) Formation of "chalcopyrite disease" penetrating the compositional zoning of sphalerite at the early stage III.