• Title/Summary/Keyword: 스카른

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Major Molybdenum Mineralization and Igneous Activity, South Korea (남한의 주요 몰리브덴 광화작용과 화성활동)

  • Choi, Seon-Gyu;Koo, Min-Ho;Kang, Heung-Suk;Ahn, Yong-Hwan
    • 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.

Occurence of Zn-Pb Deposits in Danjang-Myeon, Milyang Area (밀양 단장면 일대에 발달하는 아연-연 광화대의 산출특성)

  • Kwak, Ji Young;Kang, Chang Won;Joo, Soo Young;Jeong, Jae Han;Choi, Jin Beom
    • Journal of the Mineralogical Society of Korea
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    • v.28 no.3
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    • pp.279-292
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    • 2015
  • New occurrences of large-scaled Zn-Pb deposits are recently found in the Danjang-myeon, Milyang. They are skarn-type deposits which replaced the intercalated limestone beds in the Jeonggaksan Formation. This study aims at characterizing occurrences, mineralogy, and chemistry of Zn-Pb ores and skarn minerals. Skarn orebodies are mainly found in 3 areas, named Gukjeon-ri, Gorye-ri, and Gucheon-ri orebodies, where sphalerite found as main ore mineral in 200-300 m in height and amount of galena increases as altitude does. Ores are dark grey to dark green in color and closely related with clinopyroxene zone. They occur with hedenbergite, grossular, actinolite, epidote, and small amounts of axinite, calcite, and quartz. Main ore mineral is sphalerite which includes tiny spotted grains of galena and chalcopyrite and becomes rich in grade in association with clinopyroxene and epidote. FeS contents in sphalerite show relatively wide range between 1.53 and 23.07 mole%, whose contents intend to increase towards biotite granite known as ore-related igneous rocks. CdS contents are in the range of 0.22-0.93 mole%, showing decrease tendency from southwest (Gukjeon-ri) to northeast (Gucheon-ri). Zn-Pb deposits developed in Danjang-myeon reveal decrease in temperature with increase of altitude, leading to gradual changes in compositions of ore and skarn minerals.

Mineralization and Genetic Environments of the Central and Main Orebodies in the Manjang Deposit, Goesan (만장광상 중앙광체와 본광체의 광화작용과 생성환경)

  • Yu, Hyunmin;Shin, Dongbok
    • Journal of the Mineralogical Society of Korea
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    • v.31 no.2
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    • pp.87-101
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    • 2018
  • The Manjang deposit developed in the Hwajeonri formation of the Okcheon metamorphic belt consists of the Central and Main orebodies of Cu-bearing hydrothermal vein type and the Western orebody of Fe-skarn type. This study focuses on the Cu mineralization of the Central and Main orebodies to compare with the genetic environments of the Western orebody previously studied. The Central orebody produced pyrrhotite and chalcopyrite as major ore minerals with vein texture, while the Main orebody contains pyrite, arsenopyrite, and chalcopyrite as major ore minerals with vein, massive, and brecciated texture. Sphalerite, galena, magnetite, ilmenite, rutile, cassiterite, wolframite, and stannite are also accompanied. Local occurrence of skarn is dominated by grossular and hedenbergite, reflecting the reduced condition of the skarnization. Geothermometries of sphalerite-stannite in the Central orebody and arsenopyrite-pyrite in the Main orebody indicate the formation temperature of $204-263^{\circ}C$ and $383-415^{\circ}C$, respectively. Sulfur fugacity of $10^{-6}-10^{-7}atm$. in the Main orebody decreased toward the Central orebody. Sulfur isotope compositions of sulfide minerals from the Central and Main orebodies are 4.6-7.9‰ and 4.3-7.0‰, respectively, reflecting magmatic origin with slight influence by host rock. Considering ore mineralogy, texture as well as physicochemical conditions, the Main and Central orebodies of hydrothermal Cu mineralization reflect the characteristics of proximal and distal type ore mineralization, respectively, related to hidden igneous rocks, and they were generated under different hydrothermal systems from the Fe-skarn Western orebody.

Occurrence of the Pb-Zn Skarn Deposits in Gukjeon Mine, Korea (국전 Pb-Zn 스카른 광상의 산출상태)

  • Yang, Chang-Moon;Choi, Jin-Beom
    • Journal of the Mineralogical Society of Korea
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    • v.23 no.4
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    • pp.413-428
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    • 2010
  • The Gukjeon Pb-Zn mine was recognized as skarn deposits which replaced the limestone layer of the Jeongkansan Formation by intrusion of biotite granite in late Cretaceous. The Jeongkansan Formation is mainly composed of tuffaceous shale, and interlayers of sandstone, andesitic tuff, limestone, and conglomerate. The limestone layer is located in the lower part of the Jeongkansan Formation with 6~8 m in thickness and about 500 m in length. The Gukjeon deposits are divided into the Jukgang ore bodies once mined underground and the eastern ore bodies. Main ores are sphalerite and galena, in association with small amounts of chalcopyrite, arsenopyrite, pyrite, and pyrrhotite, etc. Skarns mainly consist of clinopyroxenes and Ca-garnets, associated with actinolite, chlorite, axinite, and calcite, etc. The Jukgang ore bodies show symmetrical distribution of zoning outward, representing clinopyroxene (hedenbergite) zone, clinopyroxene-garnet (grossular) zone, garnet (andradite) zone, and alteration zone of hornfels. $Fe^{2+}$ contents in clinopyroxenes increase with decreasing sphalerite grade. Sphalerite ores are found in all zones and $Fe^{2+}$ contents in sphalerite increase in the same way as those in clinopyroxenes, implying that clinopyroxene and sphalerite are closely related each other. It is concluded that the Gukjeon ores occurred in the ore rich zone of high grade sphalerite with less pyrite in assoication with clinopyroxene.

한국에서 일하는 외국인 과학기술자 - 새 금속광상탐사 체계적 이론 도입, 부경대 로렌스 P.제임스박사

  • Korean Federation of Science and Technology Societies
    • The Science & Technology
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    • v.33 no.12 s.379
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    • pp.82-83
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    • 2000
  • 최근 새로운 금속광상 발견으로 체계적인 이론의 도입과 탐사의 필요성에 따라 초청된 제임스박사. 그는 세계적으로 그 산출특성이 잘 알려진 칼린형 및 스카른 금광화작용의 모델을 적용하여 한국내 금광상의 잠재력과 광상의 발견에 유용한 재료를 제시할 계획이다.

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Studies on the Skarn-type Ore Deposits and Skarn Minerals in Gyeongnam Province (경남지구(慶南地區)의 스카른형(型) 광상(鑛床)의 성인(成因)과 스카른광물(鑛物)에 관(關)한 연구(硏究))

  • Woo, Young Kyun;Lee, Min Sung;Park, Hee-In
    • Economic and Environmental Geology
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    • v.15 no.1
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    • pp.1-16
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    • 1982
  • Many skarn type iron ore deposits are distributed in Kimhae-Mulgeum area of Gyeongnam Province. Integrated field, mineralogic, geochemical and fluid inclusion studies were undertaken to illustrate the character and origin of the ores in this area. The iron ore deposits in this area are NS or NNE trending fracture filling magnetite veins which are developed in andesitic rocks near the contact with late Cretaceous micrographic granite bodies. Symmetrically zoned skarns are commonly developed in the magnetite veins of this area. Zoning of skarn from center to margin of the vein are as follows; garnet quartz skarn-epidote skarn-epidote orthoclase skarn-altered andesitic rocks. Major ore mineral is magnetite and small amount of hematite, pyrite, pyrrhotite, chalcopyrite and sphalerite are associated. Vein paragenesis reveals four depositional stages; 1) skarn stage, 2) iron sulfide and oxide stage, 3) skarn stage, 4) sulfide stage Minute halite-bearing polyphase inclusions and liquid inclusions are contained in quartz. Filling temperatures range from $257^{\circ}$ to $370^{\circ}C$.

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W-Sn-Bi-Mo Mineralization of Shizhuyuan deposit, Hunan Province, China (중국 호남성 시죽원 광상의 W-Sn-Bi-Mo광화작용)

  • 윤경무;김상중;이현구;이찬희
    • Economic and Environmental Geology
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    • v.35 no.3
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    • pp.179-189
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    • 2002
  • The Geology of the Shizhuyuan W-Sn-Bi-Mo deposits, situated 16 Ian southeast of Chengzhou City, Hunan Province, China, consist of Proterozoic metasedimentary rocks, Devonian carbonate rocks, Jurassic granitic rocks, Cretaceous granite porphyry and ultramafic dykes. The Shizhuyuan polymetallic deposits were associated with medium- to coarse-grained biotite granite of stage I. According to occurrences of ore body, ore minerals and assemblages, they might be classified into three stages such as skarn, greisen and hydrothernlal stages. The skarn is mainly calcic skarn, which develops around the Qianlishan granite, and consists of garnet, pyroxene, vesuvianite, wollastonite, amphibolite, fluorite, epidote, calcite, scheelite, wolframite, bismuthinite, molybdenite, cassiterite, native bismuth, unidetified Bi- Te-S system mineral, magnetite, and hematite. The greisen was related to residual fluid of medium- to coarse-grained biotite granite, and is classified into planar and vein types. It is composed of quartz, feldspar, muscovite, chlorite, tourmaline, topaz, apatite, beryl, scheelite, wolframite, bismuthinite, molybdenite, cassiterite, native bismuth, unknown uranium mineral, unknown REE mineral, pyrite, magnetite, and chalcopyrite with minor hematite. The hydrothermal stage was related to Cretaceous porphyry, and consist of quartz, pyrite and chalcopyrite. Scheelite shows a zonal texture, and higher MoO) content as 9.17% in central part. Wolframite is WO); 71.20 to 77.37 wt.%, FeO; 9.37 to 18.40 wt.%, MnO; 8.17 to 15.31 wt.% and CaO; 0.01 to 4.82 wt.%. FeO contents of cassiterite are 0.49 to 4.75 wt.%, and show higher contents (4.]7 to 4.75 wt.%) in skarn stage (Stage I). Te and Se contents of native bismuth range from 0.00 to 1.06 wt.% and from 0.00 to 0.57 wt.%, respectively. Unidentified Bi-Te-S system mineral is Bi; 78.62 to 80.75 wt.%, Te; 12.26 to 14.76 wt.%, Cu; 0.00 to 0.42 wt.%, S; 5.68 to 6.84 wt.%, Se; 0.44 to 0.78 wt.%.

Data Fusion of Mineral Exploration Data Sets and Its Application Using Fuzzy Set Theory (광물자원탐사 자료에 대한 데이터 통합과 그 응용사례)

  • Sungwon Choi
    • Economic and Environmental Geology
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    • v.32 no.5
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    • pp.537-544
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    • 1999
  • In mineral exploration, there are many data sets which need to be created, processed and analyzed in order to discover a favorable mineralized zone. Recently, with Geographic Information System (GIS), such exploration data sets have been able to be systematically stored and effectively processed using computer technologies. In this study, most exploration data sets were first digitized and then rasterized. Furthermore, they were integrated together by using fuzzy set theory to provide a possibility map toward a target hypothesis. Our target hypothesis is "there is a skarn magnetite deposit in this study" and all fuzzy membership functions were made with respect to the target hypothesis. Test area is extended from 37:00N/l28:30E to 37:20N/I28:45E, approximately 20 km by 40 km. This area is a part of Taebaeksan mineralized areas, where the Sinyemi mine, a skarn magnetite deposit, is located. In final resultant map, high potential or possibility area coincides with the location of the Shinyemi mine. In this regard, we conclude the fuzzy set theory can be effectively applied to this study and provides an excellent example to define potential area for further mineral exploration.

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Gravity Exploration Inferring the Source Granite of the NMC Moland Mine, Jecheon, Chungbuk (충북 제천 NMC 몰랜드 광산의 관계 화성암에 대한 중력탐사)

  • Shin, Young Hong;Yoo, Bong Chul;Lim, Mutaek;Park, Yeong-Sue;Ko, In Se
    • Economic and Environmental Geology
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    • v.47 no.2
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    • pp.107-119
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    • 2014
  • NMC Moland mine, which is classified as a contact replacement or skarn deposit, has been interpreted to have been formed by Daebo igneous activity which intruded into the Joseon Supergroup, because it is quite closely located to Jecheon granite. However, an alternative interpretation was recently suggested that the mine could be related with the hydrothermal fluid originated from Cretaceous granitic rocks, bringing about skarnization and Mo mineralization. Here we present an interpretation on the source granite of the mine based on the gravity exploration: the gravity anomaly, unlike the surface geology, shows that the Muamsa granite could be the related granite of the mine, because its hidden subsurface structure is expected to be more widely extended to surrounding area of the mine and deeper than the Jecheon granite.