• Journal of the Mineralogical Society of Korea
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• v.10 no.2
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• pp.105-113
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• 1997

Mineral description and mineralogical characterization were made for the wellsite, a barrian zeolite, which found as diagenetic alterations in the Miocene pyroclastic rocks in Gampo area. The wellsite occurs together with clinoptilolite, smectite and apatite as euhedral crystallites (0.2~0.4mm) forming interpenetraion twinning in the vesicles of altered pmice fragments. Compared to other reported wellsites, the wellsite is rather silicic (Si/(Al+Fe): 3.12-3.16) and Ca-rich. Unit cell dimensions and chemical formular determined from XRD, EMPA and TGA data are as follows:a=9.883$\AA$, b=14.204$\AA$, c=8.677$\AA$, $\beta$-124.764$^{\circ}$, (Ba0.57K0.36)(Ca1.18Na0.04)Al3.9Si12.1O32.13.9H2O.The cation composition of the Gampo wellsite, which shows an exchange reaction in the form of Ba2++Ca2+=2(K++Na-), is deviated far from the compositional range of a phillipsite-harmotome series. Due to higher abundance of divalent cations (Ca, Ba) and si in the wellsite, cimpared to those of the phillipsite and harmotome reported in other areas, the zeolite seems to be characteristic of higher water content (18.7 wt%) and higher thermal stability. XRD, chemical and thermo-chemical results of the wellsite reflects that wellsite is rather a Ba- and Ca-rich end member of a phillipsite-harmotome-wellsite series than an intermediate phase of phillipsite-harmotome series or a barrian variety of phillipste.

• Journal of the Mineralogical Society of Korea
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• v.28 no.2
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• pp.83-93
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• 2015

This study investigated genetic, mineralogical and spectral characteristics of oil shale and coal samples in Dundgobi area, Mongolia. Based the Rock/Eval and Total organic carbon (TOC) analysis, kerogen type, hydrogen quantity, thermal maturity and depositional environment were confirmed. Moreover, the mineral composition of oil shale and coal samples were analyzed by XRD and spectroscopy. The result of Rock Eval/TOC analysis revealed that the samples of Eedemt deposit are immature to mature source rocks with sufficient hydrocarbon potential, and the kerogen types were classified as Type I, Type II and Type III kerogen. On the other hand, the samples from Shine Us Khudag deposit were mature with good to very good hydrocarbon potential rocks where kengen types are defined as Type I, Type II/III and Type III kerogen. According to the carbon and sulfur contents, the depositional environment of the both sites were defined as a freshwater depositional environment. The XRD analysis revealed that the mineral composition of oil shale and coal samples were quartz, calcite, dolomite, illite, kaolinite, montmorillonite, anorthoclase, albite, microcline, orthoclase and analcime. The absorption features of oil shale samples were at 1412 nm and 1907 nm by clay minerals and water, 2206 nm by clay minerals of kaolinite and montmorillonite and 2306 nm by dolomite. It is considered that spectral characteristics on organic matter content test must be tested for oil shale exploration using remote sensing techniques.

• Journal of the Mineralogical Society of Korea
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• v.12 no.1
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• pp.32-42
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• 1999

Microbial mats, the yellow and reddish brown deposits formed from the mine drainage, occur on the bottom of drain and mine tailing pond of the Ilkwang mine in Pusan, Korea. The constituents of microbial mats and their biomineralization were studied by using XRD, IR, and SEM-EDX. The upper part of the microbial mat is yellow-colored and composed of tube-shaped and small spheroid bacterial materials, which are mainly made up of amorphous and poor-crystalline iron-oxide minerals. The shape and composition of bacterial materials suggest that they are probably belong to iron-oxide mineral aggregates. The iron-oxide minerals of the yellow microbial mats are mainly goethite, but those of the reddish brown microbial mats contain abundant hematite along with goethite. This implies that with the evolution of biomats, goethite may be transformed to hematite.

• Journal of the Mineralogical Society of Korea
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• v.1 no.1
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• pp.32-39
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• 1988

The effect of soil forming factors on the pedogenesis of basaltic volcanic ash soils and the influence of allophane material on soil properties have been investigated on 5 chronosequence soils situated from at the near sea coast up to the foot slope of Mt. Halla in Jeju Island. Time seems to be the important soil forming factor which today differentiates soil of the Island. Songag and Donghong soils developed in lower elevations are older and somewhat less influenced by ash shower. However, soils developed at higher elevations, Pyeongdae and Heugag, are rather younger and strongly influence by the ash. It is also proved that the parent materials are very heterogeneous. They mainly are basaltic with some contamination of acidic volcanic ashes and continental aeolian deposits where a considerable amount of quartz encountered in most soils studied. Many physico-chemical properties of soil, such NaF pH, phosphate sorption power, pH and extractable acidity are parameters to differentiate andepts and non-andeptic soils.

• Journal of the Mineralogical Society of Korea
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• v.1 no.1
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• pp.40-47
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• 1988

Mineralogy of sand, silt and clay fractions from the five chronosequence soils of Jeju Island is studied with the X-ray, TEM and SEM techniques. Soils of Songag and Donghong situated at lower elevations are generally developed on relatively of ash or alluvial deposits and contain mainly ferromagnesian minerals and feldspars, with some quartz, mica and volcanic glass. Crystalline minerals are dominant in the clay fraction; halloysite and vermiculite are abundant but small amounts of allophane are present. Clay migration results in well developed ferrigargillan, Soils of Pyeongdae and Heugag located at higher elevations are developed on relatively young volcanic ash with some contamination of continental aeolian dust probably containing quartz which may be come from acid ash shower. The absence of clay illuivation is due to the dominance of allophane. This clay mineral is associated with some gibbsite, imogolite and halloysite.

• Journal of the Mineralogical Society of Korea
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• v.4 no.2
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• pp.141-146
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• 1991

Minerals of system Ag-Sb have been found in iead-zinc (-silver) ores from the Dongjeom and the Taebaeg ore deposits, which were formed at later stage of the Yeonhwa 1 mine mineralization. The Ag-Sb minerals are intergrown intimately with galena, pyrargyrite and alabandite. Their chemical compositions as determined by electron microprobe analyser show that they are chracterized by relatively high content of S, up to 5.89 atomic percent. Also the composition of the minerals may be separated into two: Ag3.89 Sb1.00-Ag7.19 Sb1.00 and Ag2.96 Sb1.00-Ag4.00 Sb1.00.

• Journal of the Mineralogical Society of Korea
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• v.3 no.2
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• pp.65-71
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• 1990

Compositions and thermal changes of pyrrhotites from Ohtani and Uljin mines were examined by Arnold's method and DTA analysis. The results are as follow: 1) The compositions of hexagonal type pyrrhotite are in some range from 47.23-47.42 atom.% Fe in the Ohtani mine, and 47.40-47.64 atom.% Fe in the Uljin mine. 2) The compositions of hexagonal pyrrhotite with exsoluted lamellae of monoclinic pyrrhotite are in 47.35-47.50 atom.% Fe in the Ohtani mine, and 47.15-47.40 atom.% Fe in the Uljin mine. This fact does not agree with phase diagrams of Fe-S system shown by Nakazawa and Morimoto(1970) and Sugaki and Shima(1977). 3) DTA data show two endothermic peak corresponding to ${\gamma}$ and $\beta$ transformation. Sturctural conversions from order(intermediate) to disorder(high) forms occur at about $300^{\circ}C$ for hexagonal type and further lower temperature with increasing Fe-content.

• Journal of the Mineralogical Society of Korea
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• v.10 no.2
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• pp.114-125
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• 1997

The purpose of this study is to clarify the geological occurrence, mineralogical, physico-chemical and thermal properties of the sericite ore which located in Chungha area, Kyungsangbuk-do. The geology of this area are composed mainly of hornfels and some felsite porphyry. The sericitic ore is classified into sericite, sericite-quartz and quartz-sericite ore according to mineral assemblages. Mineral components in sericite ore are mainly sericite with minor quartz, apatite, sphene, zircon, ilmenite, bismuthinite, iron oxide and etc. Sericite-quartz ore are mainly composed of sericite and quartz. Accessary minerals are muscovite, epidote, zircon, sphene, iron oxide and etc. The chemical compositions of K2O, Al2O3, & Ignition loss in sericite and sericite-quartz ore increase than that of the host rock, while the composition of SiO2, Na2O & Fe2O3 decrease. Sericite and sericite-quartz ore are characterized by the specific gravity of 2.35 and 2.44, the pH of 4.36 cP and 2.36 cP respectively. The result of size analyses of sericite ore is 11.3% in grain volume concentration between 12.9 $\mu\textrm{m}$ and 11.1$\mu\textrm{m}$, and 32.3% between 9.6$\mu\textrm{m}$ and 12.9$\mu\textrm{m}$. The thermal expansivity of sericite and sericite-quartz ore show the similar pattern. The sericite ore shows the thermal expansivity of 0.31% at 50$0^{\circ}C$, 0.39~0.75% at 600~1,00$0^{\circ}C$ and 0.74% at 1,10$0^{\circ}C$. The sericite-quartz ore show the thermal expansivity of 0.29% at 50$0^{\circ}C$, 0.36~0.72% at 600~1,000% and 0.71% at 1,10$0^{\circ}C$.

• Journal of the Mineralogical Society of Korea
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• v.5 no.1
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• pp.42-47
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• 1992

The oscillatory zoning pattern in alunite from the Sungsan mine, Korea was studied by the back-scattered electorn(BSE) imaging and electron microprobe analysis. This zoning is not visible under the polarizing microscope, but is spectacularly illustrated in BSE image. Electron microprobe analysis reveals that the zoning is substantially due to the variation in the content of Na substituting for K in the A site of the alunite structure. With increasing brightess in BSE image, conternt of K increases but that of Na decreases. Delicate fine-scale zoning and sharp boundaries between adjacent zones suggest that the zoning would be ascribed to the variation in the composition of hydrothermal fluid around the growing alunite crystals. The effective factors for such a variation would be 1) the fluctuation in the composition of entering fluid. and/or 2) the rapid change in composition of fluid due to the rapid precipitation of more stable. Na-poor alunite.

• The Journal of the Petrological Society of Korea
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• v.19 no.3
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• pp.181-197
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• 2010

This study is for finding a geoscientific factor for clarifying the source soil of the ancient earthenware finding. The used samples were the earthenware, soil and rocks, which were collected at the Gyeongju, Gyeongsan and Haman area. The chemical and mineralogical study for the samples were carried out for understanding the change of mineralogical and chemical composition among them. The mineralogical compositions of the earthenware are different from those of the soils from the surrounding area, which suggests that the mineralogical approach for clarifying the source soil of the earthenware should be difficult. Major element compositions of the earthenware also are different from those of the surrounding soils, which suggests that the comparison of the chemical composition using the major elements might be difficult for deducing the source soil of the earthenware. However, PAAS-normalized rare earth element (REE) patterns and Nd model ages among the rock, soils and earthenware from the same sampling sites show similar characteristics one another compared to those of the major element compositions. Nd-Sr isotopic systematics among the earthenware, soils and rocks also show a close relationship. Our results suggest that REE and Nd-Sr isotope geochemistry might be more useful than the other geochemical technique in clarifying the source soils of the ancient earthenware.