• 한국지구과학회지
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• 제26권7호
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• pp.674-682
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• 2005

충남 청양군 정산면에 위치한 삼성광산은 견운모를 생산하고 있는 광산으로서, 이 광산 및 주변지역에서 산출되는 견운모에 대한 지질학적 및 광물학적 연구를 실시하였다. 이 연구를 위해 야외지질조사 및 편광현미경 관찰, X선회절분석, 전자현미분석, X선형광분석, 시차열분석, K/Ar 동위원소분석 등의 실내연구를 실시하였다. 삼성광산 지역은 선캠브리아기의 화강편마암이 넓게 분포하고 있으며, 같은 시기의 운모편암이 발달하고 있다. 견운모는 화강편마암의 열수변질 작용에 의해 생성된 것으로 사료되며, 원암의 주요 구성광물인 정장석 $\to$사장석$\to$흑운모의 순서로 변질된다. 견운모화가 진행되어 감에 따라 석영의 외곽부분에서 용해작용에 의한 만곡현상이 심화되다가 점차 사라진다. 견운모로의 변질작용이 진행됨에 따라 모암의 화학성분은 $SiO_2\;and\;Na_2O$ 함량은 감소하는 반면, $Al_2O_3\;and\;K_2O$는 증가하는 양상을 나타낸다. 견운모의 생성시기는 중생대 쥬라기이며, 이 시기는 화강편마암을 관입한 흑운모화강암의 관입시기와 잘 일치한다.

• 한국광물학회지
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• 제11권2호
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• pp.69-84
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• 1998

The Daehyun sericite deposit in socheon-myun, Bongwha-gun, Kyungsangbuk-do, Korea, has been formed by the hydrothermal alteration of the Hongjesa granite of Precambrian age, leaving the muscovite granite between ore body and the Hongjesa granite as the wall rock alteration zone. The process of sericitization of granitic rock as well as chemistry and structures of sericites were studied using polarizing microscope, X-ray diffractometer (XRD), electron probe microanalyzer (EPMA) and high resolution transmission electron microscope (HRTEM). There are two genetic types of sericites having different chemistry and structure. The early sericite is of 2M1 polytype and has octahedral composition close to muscovite. It has been formed from the primary muscovite, tourmaline and quartz under a relatively high temperature. The late sericite is of 1M, 2M1 and 3T polytypes and has phengitic composition. It has been formed form feldspar, biotite, muscovite and tourmaline under a relatively low temperature. Chemical analyses show t, the early sericite has less Mg+FeT content and lower Si/AlIV ratio in tetrahedral site than the late sericite.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2003년도 춘계 학술발표회 논문집
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• pp.315-315
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• 2003

Gold mineralization at Kyaukpahto occurs as stockworks/disseminations and locally as breccia zones in silicified sandstones of Lower to Middle Eocene Male Formation of Myanmar. The mineralization is spatially related with NNE -trending fracture zones_probably tensional open fractures caused by the right-lateral Sagaing fault system. Intensive silicification, sericitization, argillic alteration, sulfidation, and decalcification are recognized in the Kyaukpahto mine area. (omitted)

• 한국광물학회지
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• 제22권1호
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• pp.13-22
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• 2009

연구지역은 울산시 울주군의 양산단층대를 통과하는 터널(복안터널) 구간으로서 터널 상부에 경부고속도로와 국도 35호선이 위치한다. 기존의 조사결과 양산단층대 통과 터널 구간은 최대 폭 100 m에 이르는 단층비지와 단층각력암이 넓게 분포한다. 연구결과 양산단층 동측부에는 셰일로 대표되는 퇴적암이 분포하는데 이들은 기계적인 파쇄작용이나 열수변질작용의 영향을 거의 받지 않았다. 양산단층 서측부에는 데사이트질응회암이 분포하며, 양산단층의 영향으로 기계적 파쇄작용과 열수변질작용이 진행되었다. 양산단층 구간은 단층운동과 관련된 기계적 파쇄작용과 녹니석화작용, 견운모화작용, 고령석화작용으로 대표되는 열수변질작용이 복합적으로 작용하여 폭 $50{\sim}130m$에 이르는 단층대가 발달한다. 기계적 파쇄작용과 열수변질작용의 특징에 의해 양산단층대는 지질공학적으로 비변질대, 변질대, 변질.파쇄대, 단층비지대 등 4개의 구간으로 구분된다. 이들 구간은 기계적 파쇄작용과 변질작용의 정도 및 양상을 달리하며, 공학적 특성을 달리한다.

• 자원환경지질
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• 제27권1호
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• pp.11-28
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• 1994

The Anyang Feldspar Mine is located in Seoksu Dong, Anyang City, Kyeonggi Do, Korea and has a long exploitation record that is once produced high grade sodium feldspars, for glaze. Geologically, This area is mainly composed of Mesozoic Jurassic biotite granite (Anyang granite) which intruded Precambrian Kyeonggi Gneiss Complex outcroped near the mining area. The deposit is localized on the southwest hill side of Anyang granite batholith and is confined in hydrothemal alteration zone formed by sodium-rich alkali hydrothermal fluids along the fractures of leucocratic granite showing later differentiation facies in the biotite granite. The hydrothermal alteration is characterized by albitization, sericitization, and desilication. The microscopic observation and EPMA, XRD analysis of the feldspar ores show that major minerals are albite and quartz and accessory minerals are orthoclase and sericite, and they are rarely associated with perthite, fluorite, zircon, kaolinite, molybdenite, microcline and iron-oxide. In the REE pattern, the strong negative Eu anomalies of the feldspar ores indicate the influence of feldspar fractionation and show similiar pattern of the host leucocratic granite. The filling temperature of quartz crystals in ore zone ranges from $276^{\circ}C$ to $342^{\circ}C$, and it is inferred that the alteration occurred by the hypothermal solution.

• 자원환경지질
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• 제32권3호
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• pp.237-245
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• 1999

The Mujeong au-Ag hydrothermal vein type deposits occur within the Teriary igneous rocks of the Janggi basin. Ore minerals consist of pyrite, pyrrhotite, sphalertite, chalcopyrite, galena, cosalite, lillianite, argentite and electrum, and associated with epidotization, sericitization and pyritization. Fluid inclusion studies reveal that ore fluids were low saline with a simple NaCl-$H_{2}O$ system. Fluid inclusion data indicate that homogenization temperatures and salinities of fluid are 150 to $340^{\circ}C$ and 1.0 to 6.5wt.% NaCl equivalent, respectively. Sulfur isotope compositions of sulfied minerals ( ${\delta}^{34}S$=6.2 to 9.6$\textperthousand$) indicate that the ${\delta}^{34}S_{H2S}$ value of ore fluids was about 10.4$\textperthousand$. This ${\delta}^{34}S_{H2S}$ value is likely consistent with and hydrothermal sulfur, whereas the fluids were highly influenced by mixing with meteoric water. Measured and calculated oxygen and hydrogen isotope values (${\delta}^{18}O_{H2O}$=-2.7 to 3.4 $\textperthousand$, ${\delta}D_{H2O}$ = -83.6 to -52.7 $\textperthousand$) of ore forming fluids suggest mixing with hydrothermal and meteoric water. Equilibrium thermodynamic interpretation by mineral assemblages and chemistry indicates that sulfur fugacities (-log $fs_2$) ore forming fluids range from 9.0 to 12.6 atm stage II.

• 자원환경지질
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• 제14권3호
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• pp.123-142
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• 1981

Granitic complex in the Woosanbong area is composed of schistose granite, two-mica granite, biotite granite, porphyritic granite and pink feldspar granite in order of intrusion. In their boundary aspects, the gradational change between porphyritic granite and pink feldspar granite is observed in field relations. All the granites of the complex are classified to quartz monzonite by the modal compositions following Bateman's classification (1961) with the exception of pink feldspar granite which belongs to granite according to the petrographical classification. The first three granites are characterized by highly development of vein and/or lens-like pegmatites in their bodies, and two others contain green hornblende uniquely. These leucocratic two-mica granite shows an unusual character in ratio of muscovite to biotite 1: 0.7 to 1:13, and contains dominantly microcline. The content of muscovite varies in places in the field. Under the polarizing microscope it is revealed that the muscovite flakes occur as the products altered from biotite partly or completely, and it usually associates with chlorite flakes nearby. These features, therefore, suggests that biotite probably has been altered to muscovite and chlorite by hydration during deuteric processes. At the same stage, sericitization of plagioclase by the hydrolytic decomposition, and transformation of orthoclase to microcline may be taken place. Accordingly, it is obviously permissible to consider the two-mica granite as a kind of 'apo-granite' by deuteric alterations during the consolidation of magma.

• 한국광물학회지
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• 제9권1호
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• pp.7-16
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• 1996

Partially sericitized tourmaline from a pegmatite, Black Hills, South Dakota, U.S.A., was investigated using high-resolution transmission electron microscopy (HRTEM). Muscovite occurs as the only alteration product of tourmaline, and it is developed extensively as narrow veinlets along the {110} and {100} cleavage directions of tourmaline, indicating that a cleavage-controlled alteration mechanism was dominant. Muscovite was characterized mainly as two-layer polytypes with minor stacking disorder, but tourmaline is almost free of structural defects. HRTEM images of tourmaline-muscovite interfaces revealed that the interfaces between two minerals are composed of well-defined {110} and {100} boundaries of tourmaline. The (001) of muscovite is in general parallel to the c-axis of tourmaline, but tourmaline and replacing muscovite do not show specific crystallographic orientation relationship; muscovite consists of numerous 100-1000$\AA$ thick subparallel packets, and the angles between the (001) of muscovite and (110) of tourmaline is highly variable. Al/Si ratios of both minerals suggest that tourmaline to muscovite alteration by late magnetic fluids has been facilitated by their similar Al/Si ratio in the incipient alteration stage, in that the hydration reaction with preservation of Al and Si would require only addition of K+ and H2O. Aluminous minerals other than muscovite were not characterized as the alteration products of tourmaline, indicating that tourmaline reacted directly to muscovite; the tourmaline alteration apparently occurred by the presence of residual fluids in which K+ is available and silica was not undersaturated.

• 자원환경지질
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• 제25권3호
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• pp.297-316
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• 1992

The Daebong gold-silver deposits is located in 8 km southwest of Cheongyang, Chungcheongnam-Do, Republic of Korea. The gold-silver-bearing hydrothermal quartz veins was formed within the Precambrian metasediments of Gyeonggi massif. Ore minerals occur as mainly of pyrite, sphalerite (0.78~6.19 wt.% Cd), galena, pyrrhotite and minor amounts of chalcopyrite, arsenopyrite, magnetite, ilmenite, chalcocite, electrum (55.00~89.55 wt.% Au) and argentite. The gangue minerals are quartz, calcite, chlorite, K-feldspar, biotite. Wall-rock alterations such as chloritization, silicification, pyritization, carbonatization and sericitization can be observed near the quartz veins. According to the mineral paragenetic sequence based on vein structure and mineral assemblages, three stage mineralizations can be recognized. Fluid inclusion, sulfur isotope and thermodynamic data show that the ore minerals were dominantly deposited at the between 388 and $204^{\circ}C$ from fluids with salinities of 8.1~0.3 wt.% equivalent NaCl, and sulfur isotope value 4.84 to 6.40 per mil of sulfides indicates igneous sources of sulfur in the hydrothermal system and fluid inclusion salinity data suggest that thermal fluids may have magmatic origin with some degree mixing of meteoric water.

• Ocean and Polar Research
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• 제23권1호
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• pp.11-21
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• 2001

K-Ar ages of the altered rocks from the Barton Peninsula are belows; altered tuffaceous andesite from southwestern part is 42 Ma, altered rocks contacted with quartz vein from southern part are 28 and 33 Ma, and advanced argillic altered andesite from northeastern part are 33 and 35 Ma. Those K-Ar ages are 10 My younger than granitic rocks of the Barton Peninsula. Hydothermal alteration of the Barton Peninsula was originated from mixing of magmatic water from parent magma of granitic rocks with meteoric water. The Al content in the hostrock is relatively constant during hydrothermal alteration, on the contrary the Mg content is in proportion to total alkali. The variation of total alkali and Mg contents in hydrothermal alteration indicates that those elements was washed out during hydrothermal alteration. The sequences of hydrothermal alteration of the Barton Peninsula is chloritization of amphiboles, sericitization of feldspars and kaolitization of sericite.