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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Mineralogical Society of Korea
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Journal DOI :
The Mineralogical Society of Korea
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Volume & Issues
Volume 5, Issue 2 - Dec 1992
Volume 5, Issue 1 - Jun 1992
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Mechanisms of Formation of Manganese Oxide Minerals in the Manganese Deposits of the Taebaeg Mt. Region, Korea
Kim, Soo-Jin ; Cho, Hyen-Goo ; Choi, Hun-Soo ;
Journal of the Mineralogical Society of Korea, volume 5, issue 1, 1992, Pages 1~5
The manganese oxide ores in the Taebaeg Mt. region have been formed by supergene weathering of the primary hydrothermal or sedimentary manganese ores. The supergenesis is controlled by the physical chemistry of the descending groundwater in the supergene zone. It includes the fundamental geological processes, such as dissolution, oxidation, transportation, precipitation, and crystallization and recrystallization. However, the fundamental mechanisms for the formation of various manganese oxide minerals are 1) replacement, 2) precipitation from solution, and 3) solid state crystallization and recrystallization. Various textures and structures of ores have been formed by these processes. Detailed paragenetic sequence of manganese oxide minerals in each ore deposit is summerized.
Formation of Illite in the Natural
System in the Hydrothermal Clay Deposit of the Bobae Mine, Korea
Choo, Chang-Oh ; Kim, Soo-Jin ;
Journal of the Mineralogical Society of Korea, volume 5, issue 1, 1992, Pages 6~13
Thermodynamic data of mineral reactions were used to construct a phase diagram for the formation of illite from andalusite at one bar and 325
in the hydrothermal alteration. Based on chemical compositions, the free energy of formation of illite coexisting with andalusite was calculated by assuming the ideal mixing ina bunary system consisting of muscovite and pyrophyllite components. For illite with structural formula
, its free energy of formation is -1147.727 kcal/mole at the condition under consideration. The stability area of illite is more narrow than that of end-member muscovite and prefers lower activity of silica. Illite was formed by hydration of andalusite while pyrophyllite decomposed. Illitization took place preferentially at margin and/or along fractures of andalusite.
Rare Metal Occurrences within the Anorthosite in the Hadong-Sanchong area, Kyungnam Province, Korea
Kim, Won-Sa ; Jeong, Ji-Gon ; Lee, Gang-Ho ; Watkinson, D.H. ;
Journal of the Mineralogical Society of Korea, volume 5, issue 1, 1992, Pages 14~21
Allanite crystals rich in rare-earth elements(REE) occur in soil developed on top of anorthositic rocks in the Jungsu-ri area of Okjong-myun, Hadong-run, where large Ti orebodies are embedded in the bed rock. In this study allanite is investigated mainly by transmitted light microscopy, electron microprobe analysis, atomic absoption spectrophotometry, X-ray diffraction, infrared spectrocopy. In addition, its specific gravity and micro=indentation hardness value are measured. Allanite occurs with max. dimension of
and coexists with quartz, epidote, zircon, biotite and muscovite. It shows nearly nonmetamict crystallinity, although
-particles bombardment from the disintegration of the radioactive element Th is detected by an autoradiography. The allanite is particularly enriched in REE(19.88-23.99 wt.%), but is deficient in CaO(8.35-10.29wt.%). Genesis of the allanite in this area is not understood yet. It is, however, assumed to have been formed from magmatic fluid rich in REE and Ti, based on the facts that it ocexists with zircon and that it has high
(0.89-1.13 wt.%) whose concentration is significant in the country rocks.
Mineralogy of Size Fractions in Sancheong Kaolin and Its Origin
Jeong, Gi-Young ; Kim, Soo-Jin ;
Journal of the Mineralogical Society of Korea, volume 5, issue 1, 1992, Pages 22~31
The Sancheong kaolin was fractionated into 9 size fractions by wet sieving, sedimentation, and centrifugation. The systematic X-ray diffraction combined with electron microscopy shows that the clay mineral composition of each size fraction is related to the original fabric of kaolin. Minerals such as halloysite (10
), kaolinite, illite, and goethite which were formed by procipitation from solution are generally concentrated in the finer fractions, whereas verniculite which was formed by pseudomorphic transformation from other primary minerals are concentrated in the coarser factions. Kaolinits of various types which were formed by precipitation or transformation show a wide size range but they are generally concentrated in the coarser fractions. Halloysite or halloysite-kaolinite clusters in coarse fractions are the fragmentation products of the walls of original boxwork clusters in coarse fractions are the fragmentation products of the walls of original boxwork kaolin which escaped the complete dispersion even through the grinding, ultrasonic agitation, and chemical treatment. Separation of fully hydrated halloysite and kaolinite was possible by systematic wet size fractionation. The coarse-grained minerals such as vermiculite and kaolinite are usually removed during the preparation of clay fraction smaller than 2
, whereas the fine-grained minerals such as illite and goethite are overlooked in X-ray diffraction of the bulk samples because of their minor contents. The systematic wet size fractionation is needed for understanding of the exact mineralogy of kaolin of weathering origin.
Application of an XRD-Pattern Calculation Method to Quantitative Analysis of Clay Minerals
Ahn, Jung-Ho ;
Journal of the Mineralogical Society of Korea, volume 5, issue 1, 1992, Pages 32~41
An XRD quantitative analytical method using calculated XRD patterns was discussed in this study, Deep-seabed sediments commonly contain smectite, illite, chlorite, and kaolinite, and XRD pattern of each clay mineral of appropriate chemical composition was simulated by using an XRD pattern calculation method. Theoretical peak intensities of specific reflections of four clay minerals (the 001 reflections of smectite and illite, the 004 reflection of chlorite, and the 002 reflection of kaolinite) were measured from calculated patterns, and MIF(mineral intensity factor)value of each phase was determined from the intensities of calculated patterns. The peak intensities obtaine from experimental XRD patterns of sediments were corrected using the MIF values so that the calibrated intensity values for the specimens are linearly proportional to the weight fraction of each phase, which is normalized to 100 wt%. The MIF method can provide accurate quantitaive results without the necessity of correcting the factors by the mass absorption coefficient of each phase. This method excludes the necessity of standard specimens having compositions that are similar to those of clay minerals in the sediment samples. Therefore, quantitaive analysis using XRD calculation method can be utilized for the specimens, for which the standard specimens are very difficult or impossible to obtain. this quantitative method can provide rapid, routine analysis results for a large number of samples which occur in similar geological environments.
Oscillatory Zoning in Alunite from the Sungsan Mine, Korea
Cho, Hyen-Goo ; Kim, Soo-Jin ;
Journal of the Mineralogical Society of Korea, volume 5, issue 1, 1992, Pages 42~47
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.
Solid Solutions in Mineral Nomenclature
Nickel, Ernest H. ;
Journal of the Mineralogical Society of Korea, volume 5, issue 1, 1992, Pages 48~51