• Journal of Conservation Science
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• v.31 no.1
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• pp.47-64
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• 2015

The excavated potteries and raw clays of the Bronze Age from the archaeological sites in the Cheonan-Asan area were studied on material scientific characteristics and homogeneity. Under the microscope, grainsize of the tempers in the potteries were distributed from less than 1mm to 10mm. Microtexture of the potteries showed various shapes and sizes of pores. In addition to the main minerals such as quartz, feldspar, mica, hornblende, chlorite and talc were found from the X-ray diffraction analysis of potteries, while talc was not found in the raw clay. Therefore, it was considered as an artificially added mineral. Firing temperature of the potteries, which did not contain chlorite, are assumed that they were baked below $850^{\circ}C$. On the other hand, the potteries which had mica and talc, are assumed that they were fired below $900^{\circ}C$. The geochemical characteristics of the potteries and raw clays showed very similar patterns, that means the potteries were produced by using the raw clay sources from each site.

• Korean Journal of Heritage: History & Science
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• v.36
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• pp.267-297
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• 2003

The plain coarse pottery from the Unjeonri Bronze Age relic sites in the Cheonan, Korea were studied on the basis of clay mineralogy, geochemistry and archaegeological interpretations. For the research, the potteries are utilized at the analysis for 6 pieces of plain coarse potteries. Color of the these potteries are mainly light brown, partly shows the yellowish brown to reddish brown. The interior, surface and inside of the pottery appear as different colors in any cases. Original source materials making the Unjeonri potteries are used of mainly sandy clay soil with extreme coarse grained irregularly quartz and feldspar. The magnetic susceptibility of the Unjeonri pottery range from 0.20 to 1.20. And the Unjeonri soil's magnetic susceptibility agree almost with 0.20 to 1.30. In the same magnetization of soil and pottery, the results revealed that the Unjeonri soil and low material of pottery are same produced by identical source materials. The Unjeonri potteries and soil are very similar patterns with all characteristics of soil mineralogy, geochemical evolution trend. The result seems to be same relationships between the behavior and enrichment patterns on the basis of a compatible and a incompatible elements. Consequently, the Unjeonri potteries suggest that made the soil to be distributed in the circumstance of the relic sites as the raw material are high in a greater part. In the Unjeonri soil, the kaolinite is common occurred minerals. However, in the Unjeonri pottery, the kaolinite was not detected in all broken pieces. The kaolinite was presumed to destroy crystal structure during the firing processes of over $550^{\circ}C$. The quartz is phase transition from ${\alpha}$-quartz to ${\beta}$-quartz at $573^{\circ}C$, but the Unjeonri pottery did not investigated any phase transition evidences of quartz. The chorite was detected within the mostly potteries and soils. As the results, the Unjeonri potteries can be interpreted by not experiencing a firing temperature over $800^{\circ}C$. The colloidal and cementing materials between the quartz and low materials during the heating did not exist in the internal part of the potteries. An any secondary compounds by heating does not appear within the crack to happen during the dry of the pottery. The hyphae group are kept as it is with the root tissue of an organic matters to live in the swampy land. In the syntheses of all results, the general firing condition to bake and make the Unjeonri pottery is presumed from $550^{\circ}C$ to $800^{\circ}C$. However, the firing condition making the Unjeonri pottery can be different firing temperature partially in one pottery. Even, the some part of the pottery does not take a direct influence on the fire.

• Economic and Environmental Geology
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• v.44 no.6
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• pp.463-474
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• 2011

The Haenam epithermal mineralized zone is located in the southwestern part of South Korea, and hosts low sulfidation epithermal Au-Ag deposit (Eunsan-Moisan) and clay quarries (Okmaesan, Seongsan, and Chunsan). Epithermal deposits and accompanying hydrothermal alteration related to Cretaceous volcanism caused large zoned assemblages of hydrothermal alteration minerals. Advanced argillic-altered rocks with mineral assemblages of alunite-quartz, alunite-dickite-quartz, and dickite-kaolinite-quartz exposed on the Okmaesan, Seongsan, and Chunsan area. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), with three visible and near infrared bands, six shortwave infrared bands, and five thermal infrared bands, was used to identify advanced argillic-altered rocks within the Haenam epithermal mineralized zone. The distinct spectral features of hydrothermal minerals allow discrimination of advanced argillic-altered rocks from non-altered rocks within the study area. Because alunite, dickite, and kaolinite, consisting of advanced argillic-altered rocks within the study area are characterized by Al-O-H-bearing minerals, these acid hydrothermal minerals have a strong absorption feature at $2.20{\mu}m$. The band combination and band ratio transformation cause increasing differences of DN values between advanced argillic-altered rock and non-altered rock. The alunite and dickite-kaolinite of advanced argillic-altered rocks from the Okmaesan, Seongsan, and Chunsan have average DN values of 1.523 and 1.737, respectively. These values are much higher than those (1.211 and 1.308, respectively) of non-altered area. ASTER images can remotely provide the distribution of hydrothermal minerals on the surface. In this way good relation between ASTER spectra analysis and field data suggests that ASTER spectral analysis can be useful tool in the initial steps of mineral exploration.

• Geomechanics and Engineering
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• v.11 no.2
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• pp.197-209
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• 2016

Clayey rock has large clay mineral content. When in contact with water, this expands considerably and may present a significant hazard to the stability of the rock in geotechnical engineering applications. This is particularly important in the present work, which focused on mitigating some unwelcomed properties of clayey rock. Changes in its physical properties were simulated by subjecting the rock to a low voltage direct current (DC) using copper, steel and aluminum electrodes. The modified mechanism of the coupled electrical and chemical fields acting on the clayey rock was analyzed. It was concluded that the essence of clayey rock electrochemical modification is the electrokinetic effect of the DC field, together with the coupled hydraulic and electrical potential gradients in fine-grained clayey rock, including ion migration, electrophoresis and electro-osmosis. The aluminum cathodes were corroded and generated gibbsite at the anode; the steel and copper cathodes showed no obvious change. The electrical resistivity and uniaxial compressive strength (UCS) of the modified specimens from the anode, intermediate and cathode zones tended to decrease. Samples taken from these zones showed a positive correlation between electric resistivity and UCS.

• Journal of the Mineralogical Society of Korea
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• v.10 no.2
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• pp.97-104
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• 1997

Based on the method of determination for relative stability of each phase from the difference among the interaction parameters of the phases consisting the mixed layer, the types of interactions between layers were specified and interaction parameter between layers in ordered domain was analytically derived as a function parameter between layers in ordered domain was analytically derived as a function of not only temperature and mole fraction of layers but also ordering parameter. Interaction parameter between the different layers in ordered phase, L is as follows:{{{{ {L }_{1 } (X,Q,T)= { C} over { Q} -4(1-2Q) { L}^{2 } - { RT} over {2} ln { 1} over {2 } - { 2RT} over { { X}_{ s} } ln { { 4QX}`_{s } ^{2 } } over {(1- { X}_{s }- { QX}_{s })( { X}_{s }- {QX }_{s } ) } }}}}L2 is the interaction parameter between ordered and disordered phase in domain and is the mole fraction of the domain which represent the infinite length of mixed layer mineral and Q and C are the reaction progress parameter and arbitrary constant, respectively. This equation was used for the I/S mixed layer clay minerals to infer the relative stability of R1 type I/S mixed layer in the temperature range from 373K to 450K. The result of calculation suggest that, owing to the decrease in interaction parameter with increasing temperature. The interaction parameter decreases more rapidly with decreasing mole fraction of smectite in domain, which is consistent with the fact that the probability of finding the series smectite layer is lo in the domain with small mole fraction of smectite layers in natural system.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.13-14
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• 2003

It is generally well known that Quaternary is characteristic geologically in terms of glacial and interglacial repeats and their associated unconformity formation. This paper deals with the first finding of the characteristic and significant meaningful unconformity between Holocene and late Pleistocene, which implies submergence and emergence of the tidal sedimentary basin along the western coastal zone of Korea during interglacial stage(IOS-5e) and glacial time(IOS-2). The stratigraphy of intertidal deposits in the Haenam Bay, western coast of Korea shows two depositional sequence units (Unit I of Holocene and Unit II of late Pleistocene) bounded by an erosional surface of disconformity. The disconformity is related to the latest Pleistocene sea-level lowstands (probably during the LGM). The Unit II is interpreted as intertidal deposit showing tidal sedimentary structures and crab burrow ichnology and has two parts (the upper part and the lower part) showing different lithology and character. The upper part of Unit II shows characteristic subaerial exposure features (emergence) and its related lithology. Such subaerially exposed upper part (more or less 4m to 5m in thickness) is characterized by yellow-brownish sediment color, cryoturbat-ed structure, crab burrow ichnofacies and high value of shear strength. Geochemical and clay mineral analyses of the upper part sediments also indicate subaerial exposure and weathering. In particular, very high value of magnetic susceptibility of the upper part in comparison to that of the lower part is interpreted as pedogenetic weathering during the subaerial exposure period.

• Nuclear Engineering and Technology
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• v.8 no.2
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• pp.69-76
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• 1976

This experiment has been carried out for the removal of long-lived radioactive-nuclides (Sr-90, Ru-106, Cs-137 and Ce-144) contained in the low-level radioactive effluents from the spent fuel reprocessing plant and nuclear power plant, in order to determine the decontaminability of various chemical coagulants and domestic clay mineral (montmorillonite). Phosphate process showed prominent efficiency for the removal of Ce-144, and lime-soda process did good removal efficiency for Sr-90. About Cs-137 copper-ferrocyanide process is much desirable. In phosphate or lime-soda process, most favorable removal efficiency was obtained at more than pH 11. The montmorillonite treated with sodium chloride showed a considerable improvement in the removal of the radioactive-nuclides. By a combined chemicals-montmorillionite process, the radioactive-nuclides could be more effectively removed than by the only chemicals process.

• Journal of the Korean Society of Tobacco Science
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• v.5 no.1
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• pp.87-95
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• 1983

This study was conducted to evaluate the affect of soil conditioners and their application rates on the growth, Yield and quality of Flue-cured tobacco. Soil conditioners for this study were Montmorillonite arid Zeolite as clay mineral source and Rice hull and Sawdust as organic source. Their application rates were 500, 1000, 2000kg/10a. The growth of tobacco plants was promoted, compared with that of Non- treated plot (control) by Zeolite, Montmorillonite and Rice hull application but decreased by Sawdust application. During tobacco growing season soil moisture content, compared with control, was increased by Zeolite and Montmorillonite application but decreased by Rice hull and Sawdust application. In contrast to soil moisture content, soil temperature was higher in the Rice hull and Sawdust plot than in the plot of Zeolite and Montmorillonite. The treatment of Sawdust, compared with control, obviously accelerated the maturity of tobacco, increased reducing Sugar but decreased total alkaloids, nicotine and nitrogen content of cured leaves. The Sawdust Plot decreased the Yield (kg/10a) with significant difference by 1 %level but significantly increased leaf quality (Won/kg) and value (Won/10a) by 1%and 5 %level, respectively. The present application , ate of Nitrogen in Korea (12.5kg/10a) seems to be excessive for Flue-cured tobacco production.

• Journal of Plant Biology
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• v.14 no.3
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• pp.1-20
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• 1971

Ecological factors limiting Stipa pulchra have been determined in experimental gardens and at several sites in the hills south and east of Monterey, California. The Stipa pulchrafacies of Valley Grassland communities were found to be dominated by that species, though a total of 36 grasses and forbs were collected and identified. Basal area was not large, but aerial cover by Stipa alone averaged over 50 per cent. Across an ecotone between a Stipa association and the California Annual Type a sudden and dramatic change was recorded. Soil measurements there, and in other nearby areas, showed a much higher clay content with more available water and elemental phosphorus at the Stipa sites. Germination of Stipa seeds was high under all laboratory and field conditions, though growth of seeldings was highly variable. Seedlings grown in Stipa woil with an abundance of water were vigorous and reached anthesis the first year. In other soils they grew less, and when grown in competition with Avena fatua they scarcely grew at all. These findings indicate that when established on desirable soils, Stipa competes well and apparently precludes the dominance of Avena fatua and other large annual grasses. On the other hand, because of a lack of vigor in its seedlings, Stipa cannot reinvade the rich more friable soils on which it was once found, and on which it was shown to grow satisfactorily. This supports the contention that Sipa pulchra was the dominant grass through much of the Valley Grassland and Foothill Woodland, but also indicates that well-drained soils and those poor in mineral nutrients probalby never supported such associations.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.171-178
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• 2020

Mountainous areas cover more than 70% of Korea. With the rapid increase in tunnel construction, tunnel-collapse incidents and excessive deformation are occurring more frequently. In addition, longer tunnel structures are being constructed, and geologically weaker ground conditions are increasingly being encountered during the construction process. Tunnels constructed under weak ground conditions exhibit long-term deformation behavior that leads to tunnel instability. This study analyzes the behavior of the bottom region of tunnels under geological conditions of long-term deformation. Long-term deformation causes various types of damage, such as cracks and ridges in the packing part of tunnels, as well as cracks and upheavals in the pavement of tunnels. We observed rapid tunnel over-displacement due to the squeezing of a fault rupture zone after the inflow of a large amount of groundwater. Excessive increments in the support member strength resulted in damage to the support and tunnel bottom. In addition, upward infiltration pressure on the tunnel road was found to cause severe pavement damage. Furthermore, smectite (a highly expandable mineral), chlorite, illite, and hematite, were also observed. Soil samples and rock samples containing clay minerals were found to have greater expansibility than general soil samples. Considering these findings, countermeasures against the deformation of tunnel bottoms are required.