• Economic and Environmental Geology
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• v.50 no.1
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• pp.73-83
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• 2017

The surveyed mines are located in a polymetallic vein, replacement, and skarn mineral district in the central Andes of Peru. Iscaycruz, which includes underground and open pit mines that produce zinc and lead concentrates, was the largest mineral deposit of an important group of base metal deposits in the Andes of central Peru. The deposits are sub-vertical seams of polymetallic ores(Zn, Cu, and Pb). These seams are hosted by Jurassic and Cretaceous sedimentary rock formation. The intrusion of igneous rocks in these formations originated metallic deposits of metasomatic and skarn types. The Raura mine is composed of polymetallic deposit of veins and replacement orebodies. The main sedimentary unit in the area is Cretaceous Machay Limestone. The Raura depression contains several orebodies each with different mineralization: predominantly Pb-Zn bearing Catuvo orebody; Ag-rich galena-bearing Lake Ninacocha orebody; Cu-Ag bearing Esperanza and Restauradora orebody. Huaron is a hydrothermal polymetallic deposit of silver, lead, zinc, and copper mineralization hosted within structures likely related to the intrusion of monzonite dikes, principally located within the Huaron anticline. Mineralization is encountered in veins parallel to the main fault systems, in replacement bodies known as "mantos" associated with the calcareous sections of the conglomerates and other favourable stratigraphic horizons, and as dissemination in the monzonitic intrusions at vein intersections.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.493-507
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• 2018

The Wooseok deposit in Jecheon belongs to the Hwanggangri Mineralized Distict of the northeastern Ogcheon Metamorphic Belt. Its geology consists mostly of limestone of the Choseon Supergroup and the Cretaceous Muamsa granite intruded at the eastern area of the deposit. The deposit shows vertical occurrence of skarn and hydrothermal vein ores with W-Mo-Fe and Cu-Pb-Zn mineralization and skarn is developed only at lower levels of the deposit. Skarn minerals are replaced or cut by ore minerals in paragenetic sequence of magnetite-hematite, molybdenite-scheelite-wollframite, and higher abundances of pyrrhotite-chalcopyrite-pyrite-sphalerite-galena. Garnet has chemical compositions of $Ad_{65.9-97.8}Gr_{0.3-32.0}Pyr_{0.9-3.0}$, corresponding to andradite series, and pyroxene compositions are $Hd_{4.5-49.7}Di_{42.3-93.9}Jo_{0.5-7.9}$, prevailing in diopside compositions, both of which suggest oxidized conditions of skarnization. On the FeS-MnS-CdS ternary diagram, FeS contents of sphalerite in vein ores decrease with increasing MnS contents from bottom to top levels, possibly relating to W mineralization in deep and Pb-Zn mineralization in shallow level. Sulfur isotope values of sulfide minerals range from 5.1 to 6.8‰, reflecting magmatic sulfur affected by host rocks. W-Mo skarn and Pb-Zn vein mineralization in the Wooseok deposit were established by spatio-temporal variation of decreasing temperature and oxygen fugacity with increasing sulfur fugacity from bottom to top levels.

• Economic and Environmental Geology
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• v.36 no.4
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• pp.257-268
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• 2003

The Cretaceous magmatism in the Gyeongsang Basin, Korea, led to the formation of two contrasting metallogenic provinces: the Haman-Gunbug-Goseong(-Changwon) (HGGC) and the Euiseong (EU). The mineralization in the HGGC metallogenic province represents copper, gold and iron of porphyry-related deposits that display close relationships in time and space with subvolcanic granitoids. Much of copper-gold-forming events in this province are consistently constrained to the period between ca. 89 and 81 Ma. The hydrothermal systems of copper-gold vein deposits in the HGGC province are associated with ore-forming fluids of high to intermediate temperature (300∼50$0^{\circ}C$) with high salinity (20∼55 equiv. wt. % NaCl). The ore-forming fluids become progressively more diluted by the incorporation of decreased quantities of magmatic water further from the nearby intrusion, suggesting significant input and fluid mixing of a meteoric water component to the magmatic fluids during the late stage of geothermal systems. In contrast, the EU metallogenic province is characterized by polymetallic vein deposits that are consistently constrained to a period of 78∼60 Ma. The geothermal systems of polymetallic vein deposits in the EU province are derived from a narrow range of intermediate temperature (200∼40$0^{\circ}C$) with relatively low salinity(1∼7 equiv. wt.% NaCl). It may represent a mixed fluid of magmatic and meteoric waters. The base-metal mineralization in the Gyeongsang Basin shows a close spatial and temporal distinction between the proximal environment derived from shallow-level granitoids in the southwestern HGGC province and the distal condition derived from volcanic environments in the northwestern EU province.

• Economic and Environmental Geology
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• v.44 no.6
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• pp.551-563
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• 2011

• Economic and Environmental Geology
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• v.42 no.1
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• pp.1-8
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• 2009

The Haman mineralized area is located within the Cretaceous Gyeongsang Basin along the southeastern part of the Korean peninsula. Almost all occurrences in the Haman area are representative of copper-bearing polymetallic hydrothermal vein-type mineralization. Within the area are a number of fissure-filling hydrothermal veins which contain tourmaline, quartz and carbonates with Fe-oxide, base-metal sulfide and sulfosalt minerals. The Gunbuk, Jeilgunbuk and Haman mines are each located on such veins. The ore and gangue mineral paragenesis can be divided into three distinct stages: Stage I, tourmaline + quartz + Fe-Cu ore mineralization; Stage II, quartz + sulfides + sulfosalts + carbonates; Stage III, barren calcite. Equilibrium thermodynamic data combined with mineral paragenesis indicate that copper minerals precipitated mainly within a temperature range of $350^{\circ}C$ to $250^{\circ}C$. During early mineralization at $350^{\circ}C$, significant amounts of copper ($10^3$ to $10^2\;ppm$) could be dissolved in weakly acid NaCl solutions. For late mineralization at $250^{\circ}C$, about $10^0$ to $10^{-1}\;ppm$ copper could be dissolved. Equilibrium thermodynamic interpretation indicates that the copper in the Haman-Gunbuk systems could have been transported as a chloride complex and the copper precipitation occurred as a result of cooling accompanied by changes in the geochemical environments ($fs_2$, $fo_2$, pH, etc.) resulting in decrease of solubility of copper chloride complexes.

• Journal of the Mineralogical Society of Korea
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• v.25 no.1
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• pp.41-50
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• 2012

페루 남동부 지역에 위치한 꾸스코 동-금을 포함한 다중금속 광상 지역의 지질은 고생대 페름기-중생대 삼첩기 변성퇴적암인 미투(Mitu)층군과 이를 관입한 동시기 관입암으로 구성되어 있다. 조사지역은 페름기-삼첩기 관입암과 관련된 U-W-Sn-Mo, Au-Cu-Pb-Zn, REE 광화작용과 관련된 금속광화 대로 알려져 있다. 특히 해당 관입암은 대자율 측정 결과 S-type, 티탄철석계열과 관련이 있는 것으로 보인다. 꾸스코 지역은 깔까 북쪽과 시꾸아니 부근에 주요 광화대가 발달하고 있다. 조사대상 광상은 아줄 동, 올미오 동, 빅토리아 금, 빠딴자 동, 나우챠피-초차까나 동, 체카 금광상이다. 아줄 광상의 모암은 안산암질암이며 광석광물로는 반동석 및 황동석이 산출하며, 동은 7.81~15.3%의 범위를 가지고 평균 10.7%이다. 올미오 광상의 모암은 흑색편암이며 엽리를 따라 산화동이 충진되어 있고, 동은 0.61~2.60%의 범위를 가지고 평균 1.74%이다. 빅토리아 광상의 모암은 변성퇴적암이며, 석영맥 충진형 광상으로 금함량은 < 0.1 g/t, 은함량은 < 0.1~< 0.3 g/t이다. 빠딴자 광상에서는 이암 또는 실트암의 층리를 따라 충진하고 있는 산화동이 산출하며, 동은 3.74~9.21%의 범위를 보이며 평균 6.21%이다. 나우챠피-초차까나 광상은 적색사암의 층리를 교대충진하고 있는 산화동 광체이며, 동은 1.62~10.5%의 범위를 가지며 평균 6.39%이다. 체카 광상은 모암인 규암이 각력화작용을 받은 부분에서 금이 산출되고 있는 것으로 보고되어있으나 분석결과 금이 탐지되지는 않았다.

• Journal of the Mineralogical Society of Korea
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• v.20 no.1 s.51
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• pp.35-46
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• 2007

Shinyemi skarn deposits occur as Fe-Mo skarn type and Pb-Zn-Cu hydrothermal replacement type along the contact between Cretaceous Shinyemi granitoids and Cambro-Ordovician mixed limestone and dolostone sequence of the Choseon Supergroup. In the lower part of Western Shinyemi ore body two stages of skarn formation have been observed: the early, stage I (magnesian) skarn with Fe mineralization and the late, stage II(calcic) skarn with Mo mineralization. The stage I skarn spatially is overprinted by stage II skarn. The stage I skarn is predominantly composed of olivine, magnetite and diopside whereas, the stage II skarn is dominated by hedenbergite and garnet. The skarnification process occurred in two stages, both prograde and retrograde for stage I and stage II skarns. In stage I, the prograde skarns, mainly composed of anhydrous silicate minerals, were formed at relatively higher temperatures (about $400\;to\;550^{\circ}C$) under low $CO_{2}$ fugacity ($X_{CO2}<0.1$) conditions. On the other hand, the retrograde skarns that consisted of hydrous minerals were formed at lower temperatures (about $300\;to\;400^{\circ}C$).

• Economic and Environmental Geology
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• v.42 no.4
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• pp.301-314
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• 2009

The Taebaeksan mineralized province, which is the most important one in South Korea, is rich in zinc-lead-tungsten-iron-copper-molybdenum-silver-gold mineral resources and has a diversity of deposit styles. These deposits principally coexist in time and space with porphyry-related epigenetic deposit such as skarn, hydrothermal replacement, mesothermal vein, and Carlin-like deposits. The magmatic-hydrothermal systems in the Taebaek fold belt is genetically characterized by the Bulguksa subvolcanic rocks(ca. $110{\sim}50\;Ma$) related to northwestward subduction of the paleo-Pacific Plate. The most important zinc-lead deposits in the area are the Uljin, Yeonhwa II and Shinyemi skarn, the Janggun hydrothermal replacement, and the Yeonhwa I intermediate-mixed (skarn/hydrothermal replacement) ones. In the present study, we present a compilation of metal production and mineral assemblage of the zinc-lead deposits. The metal difference of deposit styles in the area indicates a cooling path from intermediate-sulfidation to low-sulfidation state in the polymetallic hydrothermal system, reflecting spatial proximity to a magmatic source.

• Economic and Environmental Geology
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• v.26 no.1
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• pp.41-54
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• 1993

The Ulsan Fe-W deposit, which can be classified as a calcareous skarn deposit, is represented by ore pipe consisting principally of magnetite and lesser amounts of scheelite with minor sulphides, sulphosaits, arsenides, sulpharsenides, etc. At Ulsan mine, metasomatic processes of skarn growth may be divided broadly into two stages based on the paragenetic sequence of calc-silicate minerals and their chemical composition; early and late skarn stages. Early stage has started with the formation of highly calcic assemblages of wollastonite, diopsidic clinopyroxene and nearly pure grossular, which are followed by the formation of clinopyroxenes with salite to ferrosalite composition and grandite garnets with intermediate composition. Based on these calc-silicate assemblages, the temperatures of early skarn formations have been in the ranges of $550^{\circ}$ to $450^{\circ}$. The calc-silicate assemblages formed during the earlier half period of late skarn stage show the enrichment of notable iron and slight manganese, and the depletion of magnesium; clinopyroxenes are hedenbergitic, and grandite garnets are andraditic. The formation temperatures during this skarn stage are inferred to have been in the range of $430^{\circ}$ to $470^{\circ}C$ at low $X_{CO_2}$ by data from fluid inclusions of late andraditic garnets. The later half period of late skarn stage is characterized by the hydrous alteration of pre-existing minerals and the formation of hydrous silicates. The main iron-tungsten mineralization representing prominent deposition of magnetite immediately followed by minor scheelite impregnation has taken place at the middle of early skarn stage, while complex polymetallic mineralization has proceeded during and after the late skarn stage. Various metals and semimetals of Fe, Ni, Co, Cu, Zn, As, Mo, Ag, In, Sn, Sb, Te, Pb and Bi have been in various states such as native metal, sulphides, arsenides, sulphosaits, sulpharsenides and tellurides.

• Economic and Environmental Geology
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• v.40 no.5
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• pp.517-535
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• 2007

Two distinctive Mesozoic hydrothermal systems occurred in South Korea: the Jurassic/Early Cretaceous(ca. $200{\sim}130$ Ma) deep-level ones during the Daebo orogeny and the Late Cretaceous/Tertiary(ca. $110{\sim}45$ Ma) shallow hydrothermal ones during the Bulgugsa event. The Mesozoic hydrothermal system and the metallic mineralization in the Korean Peninsula document a close spatial and temporal relationship with syn- to post-tectonic magmatism. The calculated ${\delta}^{18}O_{H2O}$ values of the ore-forming fluids from the Mesozoic metallic mineral deposits show limited range for the Jurassic ones but variable range for the Late Cretaceous ones. The orogenic mineral deposits were formed at relatively high temperatures and deep-crustal levels. The mineralizing fluids that were responsible for the formation of theses deposits are characterized by the reasonably homogeneous and similar ranges of ${\delta}^{18}O_{H2O}$ values. This implies that the ore-forming fluids were principally derived from spatially associated Jurassic granitoids and related pegmatite. On the contrary, the Late Cretaceous ferroalloy, base-metal and precious-metal deposits in the Taebaeksan, Okcheon and Gyeongsang basins occurred as vein, replacement, breccia-pipe, porphyry-style and skarn deposits. Diverse mineralization styles represent a spatial and temporal distinction between the proximal environment of subvolcanic activity and the distal to transitional condition derived from volcanic environments. The Cu(-Au) or Fe-Mo-W deposits are proximal to a magmatic source, whereas the polymetallic or the precious-metal deposits are more distal to transitional. On the basis of the overall ${\delta}^{18}O_{H2O}$ values of various ore deposits in these areas, it can be briefed that the ore fluids show very extensive oxygen isotope exchange with country rocks, though the ${\delta}D_{H2O}$ values are relatively homogeneous and similarly restricted.