• Journal of the Mineralogical Society of Korea
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• v.32 no.2
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• pp.87-102
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• 2019

Pallancata Ag mine is located at the Ayacucho region 520 km southeast of Lima. The geology of mine area consists of mainly Cenozoic volcanic-intrusive rocks, which are composed of tuff, andesitic lava, andesitic tuff, pyroclastic flow, volcano clasts, rhyolite and quartz monzonite. This mine have about 100 quartz veins in tuff filling regional faults orienting NW, NE and EW directions. The Ag grades in quartz veins are from 40 to 1,000 g/t. Quartz veins vary from 0.1 m to 25 m in thickness and extend to about 3,000 m in strike length. Quartz veins show following textures including zonation, cavity, massive, breccia, crustiform, colloform and comb textures. Wallrock alteration features including silicification, sericitization, pyritization, chloritization and argillitization are obvious. The quartz veins contain calcite, chalcedony, adularia, fluorite, rutile, zircon, apatite, Fe oxide, REE mineral, Cr oxide, Al-Si-O mineral, pyrite, sphalerite, chalcopyrite, galena, electrum, proustite-pyrargyrite, pearceite-polybasite and acanthite. The temperature and sulfur fugacity ($f_{s2}$) of the Ag mineralization estimated from the mineral assemblages and mineral compositions are ranging from 118 to $222^{\circ}C$ and from $10^{-20.8}$ to $10^{-13.2}atm$, respectively. The relatively low temperature and sulfur-oxygen fugacities in the hydrothermal fluids during the Ag mineralization in Pallancata might be due to cooling and/or boiling of Ag-bearing fluids by mixing of meteoric water in the relatively shallow hydrothermal environment. The hydrothermal condition may be corresponding to an intermediate sulfidation epithermal mineralization.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.375-376
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• 2010

This study is shown the chemical characteristics by SEM and XRD for the Light-weight Foamed Concrete according to replacement ratio of WCP and the autoclave curing time. From the SEM of the Light-weight Foamed Concrete after hydrothermal raction, regardless of replacement ratio of WCP and the autoclave curing time, forms the crystal hydrates having various shapes such as board and fiber etc is generated. From the XRD, it seems that the tobermorite hydrate is originated from crystalized quartz.

• Economic and Environmental Geology
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• v.13 no.1
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• pp.65-68
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• 1980

Dolomite and quartz, starting materials, were mixed by the mole ratio of dolomite versus quartz with 1 : 0, 1 : 1, and 2 : 1, and of which was heated under saturated water vapor pressure of $20kg/cm^2(211.4^{\circ}C)$, $80kg/cm^2(293.6/C)$ and $120kg/cm^2(323.1^{\circ}C)$, respectively, during 20 hours. The results of the hydrothermal syntheses are as follows: 1) calcite crystals were formed at all cases of the reation 2) brucite crystals were formed when dolomite was heated under the saturated vapor pressure of $80kg/cm^2$ during 20 hours. 3) talc, tremolite, xonotlite, and antigorite were formed under saturated vapor pressure of $80kg/cm^2$ by 20 hours reaction.

• Economic and Environmental Geology
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• v.25 no.3
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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.

• Journal of Sensor Science and Technology
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• v.32 no.3
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• pp.147-153
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• 2023

Metal-organic frameworks (MOFs) of cobalt gallate were synthesized and deposited on gold electrodes using self-assembly monolayers (SAMs) and hydrothermal processing. These MOF films exhibit strong adsorption capabilities for gaseous particulates, and the use of SAMs allows the synthesis and deposition processes to be completed in a single step. When cobalt gallate is mixed with SAMs, a coordination bond is formed between the cobalt ion and the carboxylate or hydroxyl groups of the SAMs, particularly under hydrothermal conditions. Additionally, the quartz crystal microbalance (QCM) gas sensor accurately measures the number of particulates adsorbed on the MOF films in real-time. Thus, the QCM gas sensor is a valuable tool for quantitatively measuring gases, such as SO₂, NO₂, and CO₂. Furthermore, the QCM MOF film gas sensor was more effective for gas adsorption than the MOF particles alone and allowed the accurate modeling of gas adsorption. Moreover, the QCM MOF films accurately detect the adsorption-desorption mechanisms of SO₂ and NO₂, which exist as gaseous particulate matter, at specific gas concentrations.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.225-232
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• 1992

The hydrothermal alteration is evaluated using multicomponent equilibrium calculations with the program CHILLER for the reactions between hydrothermal water and rhyolite at the temperature of $300^{\circ}C$ and pressure of 500 bars. The chemical-reaction model on the depositional processes of the sericitite confirms that the hydrothermal water-rock interaction(hydrothermal alteration) is the main mechanism of the sericitite formation. The principal change in the aqueous phase during the reaction is the pH increase. Overall trends for the major species are the increase in total molalities of K, Ca, $SiO_2$, Al, Mg, Fe, Na, and sulfide in solid phase with hydrothermal water-rhyolite reaction and the decrease of them in aqeous solution by precipitation of hydrothermal products. Quartz and sericite are the first minerals to form. The sequence of minerals to precipitate following them is chlorite, epidote, pyrite and microcline as water/rock ratio decreases. Although calculated results cannot duplicate the complexities of natural hydrothermal alteration, the calculation provides thermodynamic constraints on the natural process. The calculation results resemble those of experimental studies. Sericitite forms where pH decreases and water/rock ratio increases.

• Economic and Environmental Geology
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• v.32 no.3
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• pp.293-306
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• 1999

The lower Permian jungseong Formation, Taebaegsan basin (Baegunsan Syncline), represents a coal-bearing siliciclastic succession which was later modified by the Songrim or Dabo orogeny. Sandstone perography and clay mineralogy were studied to understand the thermal history of the Jangseong Formation during basin evolution. Petrographic study indicates the Jangseong sandstones are composed of quartz, feldspar, lithic fragments (metamorphic and sedimetary), and varying proportions of matrix and cement. The dominance of quartz(<97%) over feldspar (<1%) and lithic fragments (<2%) classifies most Jangseong sandstones as quartz arenotes or quartzwackes, but lithic graywackes and sublithic arenite locally occur. The diagentic features of these sandstones include mechanical compaction, cemenation by quartz and clay minerals indentified in the Jangseong Formation by X-ray diffraction analysis are late-stage clay pore-filling. Clay minerals isdentified in the Jangseong Formation by X-ray diffaction analysis are illite, kaolinte, and pyrophyllite with a minor amount of chlorite and micas. The illite, kaolinite, and pyrophyllite appear to be largely autjigenic based on their well-crystallinity forms. There authigenic clay minerals form clay minerals form clay coats/rims and late-stage pore-filling cements, Illitecrystallinity shows that the Jangseong formation has been in late-diagenetic zone to early-epizone, which ranges in temperature from $200^{\circ}C$ to $300^{\circ}C$. In assition, kaolinite-pyrophyllite transition suggests that paleotemperature of the formation has reached at least $265^{\circ}C$. Such temperatureis likely to be consistent with homogenixation temperatures of fluid inclusions in quartz veins in the formation. Thus, the Jangseong Formation has been subjected to paleotemperature of about $265^{\circ}C$. The major heat source responsible for paleotemperature may be hydrothermal solutions. The passage of hydrothermal solutions was probably assisted by fractures created during the basin-modifying tectonism of the taebaegsan basin.

• Proceedings of the Korean Ceranic Society Conference
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• 2003.04a
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• pp.164.2-164
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• 2003

• Korean Journal of Crystallography
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• v.1 no.2
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• pp.61-65
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• 1990

Smoky quartz was grown hydrothermally. For the establishment of the best growth condition, various growth factors, such as nutrients, seed orientations, minerlizers, colorants and irradiation times were studied. By the UV-visible spectrum analysis synthetic and natural smoky quartz were characterized. As a result, smoky quartz of 120mm L X 35mm W X 14mm T with clear color tone and minimum defect was grown.

• Economic and Environmental Geology
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• v.32 no.5
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• pp.445-454
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• 1999

The Sanjeon Au-Ag deposit consists of three subparallel hydrothermal quartz-calcite veins which filled fault-related fractures (generally $N20^{\circ}$ to 35"W-trending and $70^{\circ}$ to $80^{\circ}$ SW-dipping) within quartz porphyry. The vein mineralization shows an apparent variation of mineral assemblages with paragenetic time: (1) early, white quartz + pyrite + arsenopyrite + brown sphalerite, (2) middle, white (vein) to clear quartz (vug) + base-metal sulfides + electrum + argentite, (3) late, calcite + pyrite + native silver. Mineralogic and fluid inclusion data indicate that gold-silver minerals were deposited at temperatures from 2l $0^{\circ}$ to $250^{\circ}$ with salinities of 4 to 5 wt. % equiv. NaCl and log fS2 values from -14.0 to -12.2 atm. The linear relationship between homogenization temperature and salinity data indicates that gold-silver deposition was a result of meteoric water mixing. Ore mineralization occurred at pressure conditions of about 70 bars, which corresponds to the mineralization depths of about 260 m to 700 m. There is a remarkable decrease of the calculated 1)180 values of water from 1.3 to -9.7%0 in hydrothermal fluid with increasing paragenetic time. This indicates a progressive increase of meteoric water influx in the hydrothermal system at the Sanjeon deposit. Oxygen-hydrogen, sulfur, and carbon isotope values of hydrothermal fluids indicate that the ore mineralization was formed largely from meteoric waters with the contribution of sulfur and carbon from a deep igneous source.