• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.108-109
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• 2010

IMPACT Silver 주식회사는 Zacualpan 프로젝트의 Royal Mines(이하 로얄 광산)을 인수했다. $124.5\;km^2$에 해당하는 지역의 소유권은 두 개의 멕시코 사기업으로부터 가행중인 광산의 채굴권 구입과 운영 중인 기반시설의 임대를 조건으로 한다. 프로젝트 지역은 멕시코시티로부터 남서방향으로 100 km와 Taxco Silver 광산으로부터 북서방향으로 25 km 떨어진 지점에 위치한다. 기반시설은 비포장 도로, 충분한 전력과 물의 공급 및 숙련공들을 갖추어 우수한 평가를 받고 있다. 소유권은 멕시코인의 개인소유 하에서 무한한 매장량 혹은 자원량을 갖고 운영된 채광과 가공시설을 인수하는 것이다. 소유권 지역을 대상으로 한 IMPACT Silver사의 주 탐사목적은 이미 알려진 광화대의 확장을 위한 잠재성 평가와 다른 지역에서 신규 광상의 유망지역을 발견하는 것이다. Zacualpan 프로젝트의 로얄 광산은 남동 Guerrero terrane의 북부에 위치한다. Teloloapan subterrane은 주로 저변성 녹색편암상으로 구성된 쥬라기 후기에서 백악기 초기의 화산성 퇴적층으로 구성된다. 대부분의 유망지역은 Lower Villa de Ayala층의 중성 내지 염기성 화산성 쇄설암을 모암으로 한다. 다상의 변성작용은 지역 전반에 걸쳐 나타나고, Zacualpan 광산지역에서 수반되는 광화작용을 규제한다. Zacualpan 광산지역은 Sierra Madre del Sur로 알려진 유망 광화대에 해당한다. 이 지역은 화산성 괴상 황화광상과 천열수 맥상광상이 우세하다. 대부분의 천열수 광화작용은 3.2-3.8억 년 전 마그마의 생성이 활발한 판구조 체제 동안 발생하였다. 역사적으로 가장 주요한 지역은 Lipton Vein이다. 현재 Zacualpan 지구에서 채광량은 은 200-500 g/t 정도로 보고되고 있다. 일부 지역은 고품위 은 광화작용(은 1,000 g/t 이상)을 수반하고 있으며, 이는 탐사의 주 타겟이 되고 있다. Zacualpan에서 은 광화작용은 은이 부화된 중유황 천열수 맥상광상으로 상당히 유명하다. Fresnillo, Pachuca 및 Taxco 광산을 포함한 멕시코 소유의 대규모의 잘 알려진 광산들이 이에 해당한다. 이러한 광산들은 부산물로서 금, 아연, 연이 생산된다. 이러한 광상들은 맥상과 각력상 및 산점상 또는 망상세맥의 형태로 산출된다. 광화작용은 석영과 탄산염 맥 내에 주로 황철석과 다양한 섬아연석, 방연석, 은 혹은 금 광물들을 수반한다. 경제성을 갖는 광화작용의 수직적인 연장은 평균적으로 대략 300 m이고, 멕시코 중부에 위치한 Fresnillo의 광화작용은 100 m에서 960 m의 연장을 갖는 것으로 알려져 있다. 아주 오랫동안 Zacualpan에서 광산관계자의 관측과 IMPACT Silver에서 최근 작업의 결과를 토대로, Zacualpan 광산지역의 탐사모델은 새로운 광상의 탐사를 위한 가이드로서 개발되었다. Zacualpan 광산지역에서 가장 높은 경제성을 갖는 광화작용은 북서와 남북방향의 맥 구조를 따라 수반된다. 이러한 맥 구조들은 종종 이 지역을 가로질러 수 km까지 추적되지만, 경제성을 갖는 광화작용은 맥 구조를 따라서 구조적으로 유리한 지역에서 부광대를 형성한다. 부광대를 형성하기 위한 가장 유리한 구조적 지역은 북서와 남북방향으로 발달한 맥 구조들이 교차하는 지역이다. 지난 30년간 채광된 주요 부광대는 폭이 2-6 m 이고 수평연장은 30-150 m 그리고 수직연장은 230-300 m에 이른다. 가장 높은 생산량을 보이는 부광대는 남북방향의 이차 맥들이 Guadalupe 광산의 Lipton 맥을 가로지르는 지역에서 발달한다. 남동쪽으로 현재 Compadres 광산의 Silver Shoot No. 1으로부터 고품위 은을 생산하는 지역은 북서방향의 San Agustin 맥이 북향의 Cometa Navideno 맥에 의해 절단되는 지역에서 산출한다. 모암은 광화작용을 규제하는 또 다른 중요한 요소이다. 광산지역에서 경제성을 갖는 모든 광화작용은 중성 내지 염기성 화산암 특히 안산암과 관련 모암에 배태된다. 부광대가 셰일 혹은 편암으로 전이되는 지역에서, 맥들은 소규모의 세맥으로 나뉘어 진다. Zacualpan의 전형적인 천열수 광상에서 부광대는 상부로 가면서 은의 함량이 증가하고, 하부로 가면서 연 아연의 함량이 증가하는 수직적 대상을 보인다. 금의 함량 변화는 보다 예측이 어려우나 상당히 중요하다. Zacualpan 광산지역의 탐사모델에 사용된 토양 채취, 정밀지도제작, 트렌치 및 시추탐광은 현재 IMPACT Silver사가 이 지역을 대상으로 한 가장 효율적인 탐사방법으로 입증되었다. Zacualpan 프로젝트의 로얄 광산은 하루 500 톤을 제련하는 기반시설과 수반된 채굴권을 갖는 가행 광산들을 포함한다. 현재 IMPACT Silver사는 두 곳의 타겟 지역에서 정밀지도제작, 토양 및 암석 채취, 12공 총 1866 m의 시추탐광에 의한 사전조사로 구성된 4 단계 탐사를 수행했다. 암석 1,953개, 토양 1,631 개, 389 개의 시추코어 시료가 채집되고 분석되었다. 이러한 작업은 추가탐사를 요구하는 수많은 유망 광화대를 규명했다. Compadres 광산에서 현재 가행중인 지하갱 시료는 레벨 1에서 0.9 m의 폭을 갖는 광체에서 은 680 g/t과 금 0.3 g/t, 레벨 3에서 1.67 m의 폭을 갖는 광체에서 은 12,591 g/t과 금 12.07 g/t의 품위를 갖는 것으로 나타났다. 레벨 1에서 3까지 2-3 m의 폭과 30-40 m 연장으로 채광되었다. 시추탐광은 고품위를 갖는 몇몇의 중첩된 맥을 발견했다. Compadres 광산에서 남동방향으로 200 m지점에 위치한 Soledad 지역에서 5 개의 시추공으로부터 동일 맥 시스템이 발견되었고, 고품위 부광대의 상부로 간주되는 몇몇 중요 지점이 발견되었다. 초기 단계의 탐사는 유망 시추탐광 지역인 중간정도 내지 고품위 유망 광화대를 규명했다.

• Journal of the Korean Geographical Society
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• v.30 no.1
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• pp.1-13
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• 1995

One of the oldest fossil of conifers and taxads in the Korean peninsula includes Elatocladus, Ullmannia, Walchia and dates back to the Permian period of the Palaeozoic era. The only conifer which successfully survived since the Cretaceous period is Pinus and still thrives in Korea. The extinction of Miocene conifers, such as Sciadopitys, Taxodiaceae, Metasequoia and Cryptomeria may due to the climatic deteriorations during the late Pleistocene period. However, the cryophilous conifers and taxads, e.g..Pinus, Juniperus, Abies, Picea, Cupressaceae, Larix and Taxus continued to exist from the Miocene to the late Pleistocene and became major vegetational elements in the mountainous areas of Korea. As the temperature ameliorates in the late Holocene period, thermophilous Pinus (Diploxylon) gradually had increased in numbers and became a dominant vegetation in the lowland and montane areas since 2,000 years B.P. in korea. Out of various Korean conifers and taxads, Pinus which surviving since the Cretaceous period of Mesozoic era, ranges spatially from southern coastal area to northern alpine belt of the Korean peninsula. Pinus which contains largest species number in conifers is one of the most well-adapted genus to the Korean environment. The next important conifer Juniperus dates back to the Miocene period of Cenozoic era and continuously maintains speciation and expansion of distributional range. Other major conifers and taxads of Korea include Picea, Abies, Lorix and Taxus. The restriction of distributional range of Cephralotaxus and Tsuga may due to the climatic deterioration during the Pleistocene period of Cenozoic era. The patterns of the temporal and spatial distribution of Korean conifers and taxads may provide invaluable informations for the better understanding of present-day distributional range and ecology.

• Economic and Environmental Geology
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• v.22 no.4
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• pp.303-314
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• 1989

The electrum-silver-sulfide mineralization of the Geojae island area was deposited in three stages (I, II, and carbonate) of quartz and calcite veins that crosscut Late Cretaceous volcanic rocks and granodiorite(83 m.y.). Stages I and II were terminated by the onset of fractunng and breCCIation events. Fluid inclusion data suggest that the gold-sulfide-bearing stages I and II each evolved from an initial high temperature( near $370^{\circ}C$) to a later low temperature(near $200^{\circ}C$). Each of those stages represented a separate mineralizing system which cooled prior to the onset of the next stage. The relationship between homogenization temperature and salinity in stages I and II suggests a complex history of boiling, cooling and dilution. Evidence of boiling indicates a pressure of < 100 bars, corresponding to a depth of 500 to 1,250m assummg hthostatlc and hydrostatic pressure regimes, respectively. Fluid inclusion and mineralogical evidence suggest that the electrum-silver mineralization was deposited at a temperature of $220-260^{\circ}C$ from ore fluids with salinities between 1.9 and 8.1 equivalent wt.% NaCl. Total sulfur concentration is estimated to be $10^{-3}$ to $10^{-4}$ molal. The estimated $fs_2$ and $fo_2$ range from $10^{-11.8}$ to $10^{-14}$ atm and $10^{-35}$ to $10^{-36}$ atm, respectively. The chemical conditions indicate that the dominant sulfur species in the ore forming fluids was a reduced form($H_2S$). Rapid cooling and dilution of ore-forming fluids by mixing with less-evolved meteoric waters led to gold-silver deposition through the breakdown of the bisulfide complex($Au(HS)_2$) as the activity of $H_2S$ decreased.

• Economic and Environmental Geology
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• v.43 no.5
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• pp.467-475
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• 2010

The Landsat and ASTER data have been used in mineralogical and lithological studies, and they have also proved to be useful tool in the initial steps for mineral exploration throughout Nevada mining district, US. Huge pyrophyllite quarry mines, including Jungang, Samsung, Kyeongju, and Naenam located in the southeastern part of Gyeongsang Basin. The geology of study area consists mainly of Cretaceous volcanic rocks, which belong into Cretaceous Hayang and Jindong Group. They were intruded by Bulgugsa granites, so called Sannae-Eonyang granites. To extraction of Ratio model for pyrophyllite deposits, tuffaceous rock and pyrophyllite ores from the Jungang mine used in reflectance spectral analysis and these results were re-sampled to Landsat and ASTER bandpass. As a result of these processes, the pyrophyllite ores spectral features show strong reflectance at band 5, whereas strong absorption at band 7 in Landsat data. In the ASTER data, the pyrophyllite ores spectral features show strong absorption at band 5 and 8, whereas strong reflectance at band 4 and 7. Based on these spectral features, as a result of application of $Py_{Landsat}$ model to hydrothermal alteration zone and other exposed sites, the DN values of two different areas are 1.94 and 1.19 to 1.49, respectively. The differences values between pyrophyllite deposits and concrete-barren area are 0.472 and 0.399 for $Py_{ASTER}$ model, 0.452 and 0.371 for OHIb model, 0.365 and 0.311 for PAK model, respectively. Thus, $Py_{ASTER}$ and $Py_{Landsat}$ model proposed from this study proved to be more useful tool for the extraction of pyrophyllite deposits relative to previous models.

• The Korean Journal of Petroleum Geology
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• v.12 no.1
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• pp.27-33
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• 2006

The possibility of oil reserve has been conformed because the oil has been produced by 450 barrel per day in the West Korea Bay basin of the North Korea. There is also possibility of giant oil reserve since it is geographically close to one of the biggest oil fields of Bohai Basin, China. Based on the on-going oil exploration and the present condition of investment, the areas of ongoing oil exploration are three: West Korea Bay B&C prospect explored by Swedish Taurus, the north of West Korea Bay and Anju basin explored by Canadian SOCO, and East Korea Bay explored by Australian Beach Petroleum. However, there is little or no possibility of oil reserve in the rest sea areas of three. Even though oil reserves were discovered in the some parts of land areas such as Kilju and Myungcheon, it was presumed to have no economical efficiency. Geology in West Korea Bay off the North Korea is similar to that in Bohai Bay off China. The basement consists of thick carbonate rock of the Late Proterozoic and Early Paleozoic overlain by Mesozoic ($6,000{\sim}10,000\;m$) and Cenozoic ($4,000{\sim}5,000\;m$) units. Source rocks are Jurassic black shale (3,000 m or more), Cretaceous black shale ($1,000{\sim}2,000\;m$), and pre-Mesozoic carbonates (several thousand meters). Reservoir rocks are Mesozoic-Cenozoic sandstone with high porosity and pre-Mesozoic fractured carbonate rocks. Petroleum raps are of the anticline, fault sealed, buried hill, and stratigraphic types. It absolutely needs to take up a positive attitude, the activation of ocean science and technology exchange, and the joint research and development of modern MT (Marine Technology) considering the state of establishing new international ocean order forcing on building up 200 nautical mile EEZ (exclusive economic zone) among coastal nations. Both South and North Koreas should extend the ocean jurisdiction and contiguity, and MT development dealing with the same sea areas. It is more urgent problem to find a way to have the North Korea participated in, and then to develop ocean management and ocean industry individually.

• The Journal of the Petrological Society of Korea
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• v.10 no.2
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• pp.57-81
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• 2001

In the amphibolites of the Hwanggangri area, three metamorphic zones are established like hornblende-actinolite zone (H-AZ), hornblende zone (HZ) and diopside zone (DZ) by the main mineral assemblages. Hornblende zone and hornblende-actinolite zone develope away from the diopside zone that experienced the highest thermal effect. Thus, this pattern identifies the decreasing metamorphic grade of the contact metamorphism with increasing distance from the granitic pluton. The mineral assemblages of this rock are classified into six representative groups such as $\circled1$ actinolite+plagioclase+chlorite, $\circled2$ actinolite+hornblende+plagioclase+chlorite$\pm$epidote$\pm$biotite, $\circled3$ actinolite+hornblende+plagioclass$\pm$biotite$\pm$epidote, $\circled4$ hornblende+plagioclase$\pm$biotite$\pm$chlorite, $\circled5$ hornblende+plagioclase+diopside+actinolite$\pm$epidote$\pm$chlorite, $\circled6$hornblende+plagioclase+diopside$\pm$biotite$\pm$epidote. Two metamorphic events m recognized in the amphibolites of the study area that the first metamorphism is the regional metamorphism dominantly occurred in the whole Ogcheon metamorphic belt and it gave rise to the growth of actinolite at the core or center of the amphibole grains of coarse and medium size. Its metamorphic grade ranges from the greenschist facies to epidote-amphibolite facies. The second metamorphism overlapped is the contact metamorphism caused by the adjacent granitic pluton, and its metamorphic grade is thought to reach to the low pressure part of upper amphibolite facies. According to the calculation by TWEEQU thermobarometry and amphibole-plagioclase thermometry, the metamorphic temperature of initial regional metamorphism is $439-537^{\circ}C$ under pressure of 4.6-7.3 kb and its peak temperature and pressure are considered to reach to the range of 492-537 and 5.2-7.3 kb. And the temperature range of contact metamorphism occurred by intrusion of cretaceous granitic body, is $588-739^{\circ}C$ under pressure of 2.6-5.2 kb and its peak temperature and pressure are estimated as having the range of $697-739^{\circ}C$ and 3.8-5.2 kb that this amphibolites are estimated to pass through the metamorphic evolution of both the rise of temperature and the drop of pressure.

• Economic and Environmental Geology
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• v.48 no.1
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• pp.1-13
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• 2015

The geology of the Seungryung Zn deposit, located in the Muzu basin, consists of Precambrian leucocratic granitic gneiss, Cretaceous clastic rocks, pyroclastic rocks, and intrusive rocks. The deposit shows a weakly skarnized hydrothermal replacement ore developed along limestone bed in the gneiss. The mineralization can be divided into three stages: the early skarnization producing garnet and pyroxene, the main mineralization in the middle stage precipitating most metallic minerals such as magnetite, sphalerite, chalcopyrite, pyrrhotite, Pb-Ag-Bi-S system minerals, and the late stage for altered or low temperature minerals such as chlorite and marcasite. Pb-Ag-Bi-S system minerals include heyrovskite-eskimoite solid solution, lillianite-gustavite solid solution, and vikingite. Chalcopyrite diseases are quite common in sphalerite showing bead chains and dusting textures. The ${\delta}^{34}S$ values of sulfides minerals are concentrated within the narrow range of 3.4~4.1‰ for pyrite, 3.3~4.3‰ for sphalerite, 4.0~4.3‰ for chalcopyrite, and 2.8‰ for galena, suggesting that most sulfur is of igneous origin. Sulfur isotope geothermometry is calculated to be $346{\sim}431^{\circ}C$, implying that the mineralization occurred at relatively high temperature. FeS contents of sphalerite are relatively high in the range of 6.58~20.16 mole% (avg. 16.58 mole%) with the enrichment of Mn compared to Cd, similarly to representative skarn Pb-Zn deposits in South Korea. On the contrary, sphalerite from Au-Ag deposits in the Seolcheon mineralized zone around the Seungryung deposit is enriched in Cd, showing similar feature like representative epithermal Au-Ag deposits. This suggests that around the related igneous rocks, magnetite and sphalerite were produced at high temperature in the Seungryung deposit, and with decreasing temperature and compositional change of mineralizing fluids, Au-Ag mineralization proceeded in the Seolcheon mineralized zone.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.137-148
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• 2010

The Myoungbong mine located in Boseong-gun, Jellanamdo consists of Au-Ag bearing quartz veins which filled the fissures of Bulguksa granitic rocks of Cretaceous. The tailings obtained from the Myungbong mine were used to investigate the effects of various processes, such as oxidation of primary sulfides and formation(alteration) of secondary and/or tertiary minerals, on arsenic immobilization in tailings. This study was conducted via both mineralogical and chemical methods. Mineralogical methods used included gravity and magnetic separation, ultrasonic cleaning, and instrumental analyses(X-ray diffractometry, energy-dispersive spectroscopy, and electron probe microanalyzer) and aqua regia extraction technique for soils was applied to determine the elemental concentrations in the tailings. Iron (oxy)hydroxides formed as a result of oxidation of tailings were identified as three specific forms. The first form filled in rims and fissures of primary pyrites. The second one precipitated and coated the surfaces of gangue minerals and the final form was altered into yukonites. Initially, large amounts of acid-generating minerals, such as pyrite and arsenopyrite, might make the rapid progress of oxidation reactions, and lots of secondary minerals including iron (oxy)hydroxides and scorodite were formed. The rate of pH decrease in tailings diminished, in addition, as the exposure time of tailings to oxidation environments was prolonged and the acid-generating minerals were depleted. Rather, it is speculated that the pH of tailings increased, as the contribution of pH neutralization reactions by calcite contained in surrounding parental rocks became larger. The stability of secondary minerals, such as scorodite, were deteriorated due to the increase in pH, and finally arsenic might be leached out. Subsequently, calcimn and arsenic ions dissociated from calcites and scorodites were locally concentrated, and yukonite could be grown tertiarily. It is confirmed that this tertiary yukonite which is one of arsenate minerals and contains arsenic in high level plays a crucial role in immobilizing arsenic in tailings. In addition to immobilization of arsenic in yukonites, the results indicate that a huge amount of iron (oxy)hydroxides formed by weathering of pyrite which is one of typical primary minerals in tailings can strongly control arsenic behavior as well. Consequently, this study elucidates that through a sequence of various processes, arsenic which was leached out as a result of weathering of primary minerals, such as arsenopyrite, and/or redissolved from secondary minerals, such as scorodite, might be immobilized by various sorption reactions including adsorption, coprecipiation, and absorption.

• Economic and Environmental Geology
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• v.44 no.6
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• pp.463-474
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• 2011

The Haenam epithermal mineralized zone is located in the southwestern part of South Korea, and hosts low sulfidation epithermal Au-Ag deposit (Eunsan-Moisan) and clay quarries (Okmaesan, Seongsan, and Chunsan). Epithermal deposits and accompanying hydrothermal alteration related to Cretaceous volcanism caused large zoned assemblages of hydrothermal alteration minerals. Advanced argillic-altered rocks with mineral assemblages of alunite-quartz, alunite-dickite-quartz, and dickite-kaolinite-quartz exposed on the Okmaesan, Seongsan, and Chunsan area. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), with three visible and near infrared bands, six shortwave infrared bands, and five thermal infrared bands, was used to identify advanced argillic-altered rocks within the Haenam epithermal mineralized zone. The distinct spectral features of hydrothermal minerals allow discrimination of advanced argillic-altered rocks from non-altered rocks within the study area. Because alunite, dickite, and kaolinite, consisting of advanced argillic-altered rocks within the study area are characterized by Al-O-H-bearing minerals, these acid hydrothermal minerals have a strong absorption feature at $2.20{\mu}m$. The band combination and band ratio transformation cause increasing differences of DN values between advanced argillic-altered rock and non-altered rock. The alunite and dickite-kaolinite of advanced argillic-altered rocks from the Okmaesan, Seongsan, and Chunsan have average DN values of 1.523 and 1.737, respectively. These values are much higher than those (1.211 and 1.308, respectively) of non-altered area. ASTER images can remotely provide the distribution of hydrothermal minerals on the surface. In this way good relation between ASTER spectra analysis and field data suggests that ASTER spectral analysis can be useful tool in the initial steps of mineral exploration.

• Journal of the Mineralogical Society of Korea
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• v.23 no.1
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• pp.1-13
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• 2010

The Yugeum deposit in Youngduk in Gyungsangbuk-do is emplaced in the Cretaceous granitoids located in the Northeastem Gyeongsang Basin. Gold-bearing quartz veins filling the fracture with a direction of $N19^{\circ}{\sim}38^{\circ}W$ are most abundantly distributed within the Younghae granodiorite body. The formation of quartz veins can be classified into three main stages: barren quartz stage, auriferous quartz vein stage, and finally the extensive sulfide mineralization stage. Various sulfide minerals such as pyrite, chalcopyrite, galena, sphalerite, and arsenopyrite were precipitated during the hydrothermal gold mineralization process. Gold commonly occurs as fine-grained electrum in sulfides with high Au concentration (up to 93 wt%) compared to Ag. During the early gold mineralization stage, the temperature and pressure of the fluids are in the range of $220{\sim}250^{\circ}C$ and 730~1800 bar, and the oxygen fugacity is between $10^{-27}$ and $10^{-31.7}$ atm. On the other hand, the fluids of the late stage mineralization are characterized by temperature of $290{\sim}350^{\circ}C$ and pressure of 206~472 bar, and the oxygen fugacity is in the range of $10^{-26.3}{\sim}10^{-28.6}$ atm. The sulfur isotope compositions of sulfide minerals are in the range of $0.2{\sim}4.2^{\circ}/_{\circ\circ}$, while the ${\delta}^{34}SH_2S$ values range from 1.0 to $3.7^{\circ}/_{\circ\circ}$. The Ag/Au atomic ratios of electrum ranges from 0.15 to 1.10, and Au content is higher than Ag in most electrum. During the main gold mineralization stage at the relatively high temperature condition and with pH from 4.5 to 5.5, the stability of ${AuCl_2}^-$ increased while the stability of ${Au(HS)_2}^-$ decreased. Considering the pressure estimated in this deposit, the temperature of the ore fluid reached higher than $350^{\circ}C$ and ${AuCl_2}^-$ became an important species for the gold transportation. As mineralization proceeded with decreasing temperature and increasing pH and $f_{o2}$, the precipitation of sulfide minerals and accompanying electrum occurred.