• The Journal of the Petrological Society of Korea
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• v.23 no.4
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• pp.311-324
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• 2014

The Hongjeom formation of the Pyeongan Supergroup in the Munkyeong coalfield mainly consists of metapsammite and metapelites. Metampelites occur as slate preserving chloritoid+chlorite+muscovite and andalusite+biotite+chlorite+muscovite mineral assemblages. Chloritoid and andalusite occur as porphyroblast, and the matrix composed of fine-grained micas. Metamorphic P-T conditions for these mineral assemblages are $510-520^{\circ}C$ and 3.0-3.5kbar based on P-T pseudosection in $MnO-K_2O-FeO-MgO-Al_2O_3-SiO_2-H_2O(MnKFMASH)$ system and isopleth intersections of Fe/(Fe+Mg) ratios in chloritoid and chlorite. The medium temperature and low pressure metamorphism resulted from a higher geothermal gradient ($40-45^{\circ}C/km$) condition than that of burial metamorphism. The youngest (SHRIMP U-Pb age; ca. 327-310 Ma) detrital zircon grains from the Hongjeom formation display oscillatory zoning and relatively high Th/U ratio (0.60-1.12). Based on the previous sedimentary, paleontological, and geochronological studies in the Taebaeksan basin together with results of this study, we suggest that (1) initial deposition of the Hongjeom formation was contemporaneous with a magmatic activity in the provenance, (2) the Pyeongan Supergroup was deposited in an arc-related basin at an active continental margin during the Carboniferous to Permain, and (3) magmatic activities occurred repetitively in relatively short interval in the active continental margin had continuously supplied sediments to the basin.

• Korean Journal of Environment and Ecology
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• v.36 no.6
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• pp.553-565
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• 2022

Awareness of the ecological value and importance of protected areas has increased as climate change accelerates, and there is a need for research on ecosystem services provided by nature. The natural park, which is a representative protected area in Korea, has a system of national parks, provincial parks, and county parks. National parks are managed systematically by the Korea National Park Service, but local governments manage provincial parks and county parks. There may be the same hierarchical differences in naturalness (habitat quality) depending on the hierarchy of the natural parks, but it has not been verified. To identify differences, we examined 22 mountain-type natural parks using habitat quality using the INVEST model developed by Stanford University. The analysis of the habitat quality, regardless of the type and area of the natural park, showed that it was higher in the order of Taebaeksan National Park (0.89), Juwangsan National Park (0.87), Woongseokbong County Park (0.86), and Gayasan National Park (0.85). The larger the area, the higher the value of habitat quality. A comparison of natural parks with similar areas showed that the habitat quality of national parks was higher than that of provincial parks and parks. On the other hand, the average habitat quality of county parks was 0.83±0.02, which was 0.05 higher than that of provincial parks at 0.78±0.03. Furthermore, the higher the proportion of forest areas within the natural park, the higher the habitat quality. The results confirmed that the naturalness of natural parks was independent of their hierarchy and that there are differences in naturalness depending on land use, land coverage, and park management.

• Korean Journal of Environment and Ecology
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• v.36 no.1
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• pp.102-111
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• 2022

Among protected areas, National Parks are rich in biodiversity, and the benefits of ecosystem services provided to human are higher than the others. Ecosystem service evaluation is being used to manage the value of national parks based on objective and scientific data. Ecosystem services are classified into four services: supporting, provisioning, regulating and cultural. The purpose of this study is to evaluate habitat quality among supporting services. Habitat Quality Model of InVEST was used to analyze. The coefficients of sensitivity and habitat initial value were reset by reflecting prior studies and the actual conditions of protected areas. Habitat quality of 21 national parks except Hallasan National Park was analyzed and mapped. The value of habitat quality was evaluated to be between 0 and 1, and the closer it is to 1, the more natural it is. As a result of habitat quality analysis, Seoraksan and Taebaeksan National Parks (0.90), Jirisan and Odaesan National Parks (0.89), and Sobaeksan National Park (0.88) were found to be the highest in the order. As a result of comparing the area and habitat quality of 18 national parks except for coastal-marine national parks, the larger the area, the higher the overall habitat quality. Comparing the value of habitat quality of each zone, the value of habitat quality was high in the order of the park nature preservation zone, the park nature environmental zone, the park cultural heritage zone, and the park village zone. Considering both the analysis of habitat quality and the legal regulations for each zone of use, it is judged that the more artificial acts are restricted, the higher the habitat quality. This study is meaningful in analyzing habitat quality of 21 National Parks by readjusting the parameters according to the situation of protected areas in Korea. It is expected to be easy to intuitively understand through accurate data and mapping, and will be useful in making policy decisions regarding the development and preservation of protected areas in the future.

• Economic and Environmental Geology
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• v.28 no.6
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• pp.635-646
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• 1995

Mineralized zone in the Dongyang talc deposits occurs on the lowest dolomite member of the Hyangsanri Dolomite belonging to the Ogcheon Supergroup. Ore bodies are emplaced as pipe-like body along the axis of minor folds plunging $40^{\circ}$ to the west developed in these dolomite layers. Amphibolite and chlorite schist are found along the upper or lower contact of all ore bodies (Kim et al., 1963; Park and Kim, 1966). Following the recrystallization and silicification of dolomite, tremolite and tabular and leafy talc(I) of the earlier stage formed, and microcrystalline talc(II) formed in the later stage. Talc(l) and tremolite formed by the reaction between dolomite and the fluid. Whereas talc (II) formed by the reaction between dolomite and fluid, or by the reaction between early formed tremolite and fluid. During the early stage of mineralization, the fluid was the $H_2O-CO_2$ system dominant in $CO_2$, In the later stage, the composition of the fluid changed to $H_2O-NaCl-CO_2$system, and finally to the $H_2O-NaCl$ system. The pressure and temperature conditions of the formation of tremolite associated with talc(I) were 1,640~2,530 bar, and $440{\sim}480^{\circ}C$, respectively. The pressure and temperature condition of talc(II) ore formation was 1,400~2,200 bar, and $360{\sim}390^{\circ}C$, respectively. These conditions are much lower than the metamorphic pressure and temperature of the rocks from the Munjuri Formation located about 5 km to the noJ:th of Dongyang talc deposit ${\delta}^{13}C$ and ${\delta}^{18}O$ values of dolomite which is the host rock of the talc ore deposit are 2.9~5.7‰ (PDB), and -7.4~l6.8‰ (PDB), respectively. These values are little higher than those from the Cambro-Ordovician limestones of the Taebaeksan region, but belong to the range of the unaltered sedimentary dolomite. ${\delta}^{18}O$and ${\delta}D$ values of the talc from Dongyang deposit are 8.6~15.8‰ (vs SMOW), and -65~-90‰ (vs SMOW), respectively, belonging to the range of magmatic origin. These values are quite different from those measured in the metamorphic rocks of Munjuri and Kyemyungsan Formation. ${\delta}^{34}S$ value of anhydrite is 22.4‰ (CDT), which is much lower than ${\delta}^{34}S$ (30‰ vs COT) of sulfate of early Paleozoic period, and indicates the possibility of the addition of magmatic sulfur to the system. Talc ores show the textures of weak foliation and well developed crenulation cleavages. Talc ore deposit in the area is concluded as hydrothermal replacement deposit formed before the latest phase of the deformations that Ogcheon Belt has undergone.