• Title/Summary/Keyword: 모암(母巖)

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Element Dispersion by the Wallrock Alteration of Daehyun Gold-silver Deposit (대현 금-은광상의 모암변질에 따른 원소분산)

  • Yoo, Bong Chul
    • Economic and Environmental Geology
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    • v.46 no.2
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    • pp.199-206
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    • 2013
  • The Daehyun gold-silver deposit consists of two hydrothermal quartz veins that fill NE-trending fractures in the Cambro-Ordovician calcitic marble. I have sampled wallrock, hydrothermaly-altered rock and gold-silver ore vein to study the element dispersion and element gain/loss during wallrock alteration. The hydrothermal alteration doesn't remarkably recognized at this deposit and consists of mainly calcite, dolomite, quartz and minor epidote. The ore minerals composed of arsenopyrite, pyrrhotite, pyrite, sphalerite, stannite, chalcopyrite, galena, electrum, native bismuth and silver-bearing mineral. Based on analyzed data, the chemical composition of wallrock consists of mainly $SiO_2$, CaO, $CO_2$ with amounts of $Al_2O_3$, $Fe_2O_3(T)$ and MgO. The contents of $SiO_2$, $Fe_2O_3(T)$, MgO, CaO and $CO_2$ vary significantly with distance from ore vein. The element dispersion doesn't remarkably recognized during wallrock alteration and only occurs near the ore vein margin because of physical and chemical properties of wallrock. Remarkable gain elements during wallrock alteration are $Fe_2O_3(T)$, total S, Ag, As, Bi, Cd, Cu, Ni, Pb, Sb, Sn, W and Zn. Remarkable loss elements are $SiO_2$, MnO, MgO, CaO. $CO_2$ and Sr. Therefore, Our result may be used when geochemical exploration carry out at deposits hosted calcitic marble in the Hwanggangri metallogenic district.

Element Dispersion by the Wallrock Alteration of Janggun Lead-Zinc-Silver Deposit (장군 연-아연-은 광상의 모암변질에 따른 원소분산)

  • Yoo, Bong Chul
    • Economic and Environmental Geology
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    • v.45 no.6
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    • pp.623-641
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    • 2012
  • The Janggun lead-zinc-silver deposit is hydrothermal-metasomatic deposit. We have sampled wallrock, hydrother-maly-altered rock and lead-zinc-silver ore vein to study the element dispersion during wallrock alteration. The hydrothermal alteration that is remarkably recognized at this deposit consists of rhodochrositization and dolomitization. Wallrock is dolomite and limestone that consisit of calcite, dolomite, quartz, phlogopite and biotite. Rhodochrosite zone occurs near lead-zinc-silver ore vein and include mainly rhodochrosite with amounts of calcite, dolomite, kutnahorite, arsenopyrite, pyrite, chalcopyrite, sphalerite, galena and stannite. Dolomite zone occurs far from lead-zinc-silver ore vein and is composed of mainly dolomite and minor calcite, rhodochrosite, pyrite, sphalerite, chalcopyrite, galena and stannite. The correlation coefficients among major, trace and rare earth elements during wallrock alteration show high positive correlations(dolomite and limestone = $Fe_2O_3(T)$/MnO, Ga/MnO and Rb/MnO), high negative correlations(dolomite = MgO/MnO, CaO/MnO, $CO_2$/MnO, Sr/MnO; limestone = CaO/MnO, Sr/MnO). Remarkable gain elements during wallrock alteration are $Fe_2O_3(T)$, MnO, As, Au, Cd, Cu, Ga, Pb, Rb, Sb, Sc, Sn and Zn. Remarkable loss elements are CaO, $CO_2$, MgO and Sr. Therefore, elements(CaO, $CO_2$, $Fe_2O_3(T)$, MgO, MnO, Ga, Pb, Rb, Sb, Sn, Sr and Zn) represent a potential tools for exploration in hydrothermal-metasomatic lead-zinc-silver deposits.

Mathematical Models on Diffusive Loss of Non-Aqueous Phase Organic Solvents from a Disk Source (디스크소스로부터 NAPL의 확산손실에 관한 수학적 모델)

  • Yoon, In-Taek;S.E., Dickson
    • Journal of Soil and Groundwater Environment
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    • v.13 no.6
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    • pp.40-49
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    • 2008
  • Matrix diffusion from planar fractures was studied mathematically and through physical model experiments. Mathematical models were developed to simulate diffusion from 2D and 3D instantaneous disk sources and a 3D continuous disk source. The models were based on analytical solutions previously developed by Carslaw and Jaeger (1959). The mathematical simulations indicated that the 2D scenario produces significantly different results from the 3D scenario, the time for mass disappearance is significantly larger for continuous sources than for instantaneous sources, the normalized concentration generally decreased over time for instantaneous sources while it increased over time for continuous sources, diffusion rates decrease significantly over time and space, and the normalized mass loss from the source zone never reaches 1 for continuous sources due to the semi-infinite integral. The simulations also showed that disappearance times increase exponentially with increasing source radii and matrix porosity, and decrease with increasing aqueous-phase NAPL solubilities.

Characteristics Changes of Weathered Soil by Weathering (풍화에 따른 풍화토의 특성 변화)

  • 권오순;정충기
    • Geotechnical Engineering
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    • v.14 no.5
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    • pp.53-66
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    • 1998
  • Since weathered soils are made by weathering process, the characteristics of weathered soils are strongly related to the originated rock and its forming process. Investigations on the originated rock and the weathering environments that decide the forming process are indispensable for the appropriate analysis on weathered soils. In this study, forming process of weathered soil is investigated by geological viewpoint. Test results show that weathering of rock is closely related to the distribution of rock-forming mineral and forming process. Weathered granite soils have the isotropic in-situ stress state and shearing behavior caused by the non-directional characteristics of originated rock. And weathered gneiss soils have the directional characteristics that mechanical behavior is determined by internal discontinuities. It it proved that the weathering resistance of Quarte is greater than that of feldspar and mica, and it is concluded that the thickness of weathered region is greatly influenced by the distribution of rock-forming mineral.

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부여산 귀사문석옥에 대한 광물학적 연구

  • Yeo Jin-Yeong;Kim Dong-Hwan;An Hui-Jin;Yun Sang-Hwa;Kim Won-Sa
    • 한국지구과학회:학술대회논문집
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    • 2006.02a
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    • pp.245-250
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    • 2006
  • 부여군 지선리에 있는 한국녹옥광산에서는 보석학 가치가 매우 우수한 귀사문석옥 광상이 형성되어 있다. 모암인 사문암은 페리도타이트와 같은 초염기성암이 저급변성작용 또는 열수변질작용을 받아 만들어진 것으로, 그 후 시대미상의 석류석맥의 관입함에 따라 양 접촉부에 귀사문석 광체가 형성되어 있다. 귀사문석옥은 안티고라이트 사문석이며, 그 광물조직이 모암인 사문암과는 크게 차이를 나타낸다. 짙은 녹색을 띠게 하는 발 색소는 주로 Fe이며, $755^{\circ}C$에서 탈수작용이 일어나며, $830^{\circ}C$에서 감람석으로 결정구조가 변한다. 이러한 실험적 사실은 모암인 사문암은 초염기성암이 열수변질작용을 받아 변한 것임을 의미한다.

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Effect of Acid Deposition on the Acidification of Surface Water II : Column and the Field Studies (산성강하물이 지표수의 산성화에 미치는 영향 II: 컬럼연구 및 현장조사)

  • 김영관;우경식
    • Journal of Korea Soil Environment Society
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    • v.2 no.1
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    • pp.35-44
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    • 1997
  • A column study using artificial acid rain was conducted to evaluate the buffering capacities in soil layer and host rock. In an effort to compare the effect of composition of host root two valleys of which compositions of host rock are different were chosen within the study area and the pHs of the water flowing in the valleys were measured from May, 1996 to October, 1996. The pHs of the artificial acid rain prepared by adding appropriate amounts of both sulfuric and nitric acids to distilled water were 3, 4, and 5, and the column effluents were analyzed for major cations and anions. The cation exchange capacities(CECs) of A Horizon and the B Horizon were 9.68 and 6.16 meq/100g, respectively, Compared to the B Horizon, the pH in the column effluent of A Horizon with larger CEC was higher. The sums of $Ca^{2+}$, $Mg^{2+}$, $Na^{+}$in the column effluents gradually decreased, indicating the loss of CEC by acid rain. The field study showed that pHs of the surface water in the valleys increased as the water flows downwards. The magnitude of this buffering capacity was greater for the valley in which smectite in addition to kaolinite and illite was a weathered product of host rocks. This also indicates that host rock as well as soil layer retains the buffering capacity.

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Differences in Morphological Properties and Soil Moisture Characteristics Curve of Cultivated Land Derived from Major Parent Rocks in Yeong-nam Province Areas (영남지역 주요 모암지대별 밭토양 모래입자의 형태적 특성 및 토양수분특성곡선의 차이에 관한 연구)

  • Sonn, Yeon-Kyu;Jung, Yeun-Tae;Son, Il-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.32 no.3
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    • pp.211-214
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    • 1999
  • To acknowledge the differences in soil physical properties of cultivated land derived from major parent rocks in Yeong-nam areas, we investigated Riley's projection sphericity(one of the morphological properties) of sand and made up Soil Moisture Characteristics Curve(SMCC). The averages in Riley s projection sphericity range from 0.63 to 0.67 in soils derived from Sedimentary rocks than 0.56 to 0.61 in soils derived from igneous rocks. In case of soils derived from igneous rocks, the Riley's projection sphericity is lower as the particle size get to be smaller. The differences of SMCC were larger in the fine loamy soils than in coarse loamy soils. The moisture retention was higher in the soils derived from Sedimentary rocks than in the soils derived from Igneous rocks. After we transformed the water retention into dimensionless scale value by available water ratio, the SMCC was nearly unchangeable in the tested soils except for fine loamy soils derived from Sedimentary rock, but was not correlated with soil texture or parent rocks.

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Geology and Polymetallic Mineralization in the Cusco Area, Peru (페루 꾸스코 지역 지질특성과 다금속 광화작용)

  • Ryoo, Chung-Ryul;Heo, Chul-Ho;Munoz, Michael Valencia;Cornejo, Raymond Rivera;Angeldonis, Alexander Santisteban
    • 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.