• Journal of the Korean earth science society
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• v.30 no.3
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• pp.267-281
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• 2009

Cretaceous intrusive and extrusive rocks are widely distributed in the southern part of the Korean peninsula, possibly the result of intensive magmatism which occurred in response to subduction of the Pacific plate beneath the northeastern part of the Eurasian plate. Geochemical and petrological study on the Cretaceous granitic rocks of the Yeosu area were carried out in order to constrain the petrogenesis of the granitic rocks and to establish the paleotectonic environment of the southwestern part of the Korean peninsula. Igneous rocks of the Yeosu area consist of diorite, hornblende biotite pite and micrographic granite. Chondrite normalized REE patterns show generally enriched in LREE ($(La/Lu)^{cN}$=4.2-13.3). Diorites show flat to slight negative Eu anomalies while micrographic granites have strong negative Eu anomalies. The ${\Sigma}REE$ of the granites are 76.2-235 ppm, which corresponds to the range of the continental margin granite. Whole rock chemical data of the granitic rocks from the Yeosu area indicate that the rocks have characteristics of calc-alkaline series in the subalkaline field. On the A/NK vs. A/CNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type and volcanic arc granite (VAG). Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at continental margin during the subduction of Pacific plate.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.148-151
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• 2002

To clarify of chemical contents for the Keumsan ginseng, two attempts have been done for two year: 2 year and 4 year-ginsengs coilected from the phyllite(Ph0 and granite area(Gr), and 1 year, 2 year and 3 year-ginsengs collected from the phyllite(Ph), shale(Sh) and granite (Gr), In the first attempt, the soil contents of the Ph are high in most of elements. In the comparisons between ages of the ginseng, regardless the area, most of the elements are high in the 4 year and these trends are distinctive in the granite area. In the comparisons of the areas, 2 year-ginsengs of the Ph show high contents in the most of the elements. Comparisons between upper part(leaf and branch) and root part of the ginsengs show that in the 2 year-ginseng, the Gr is high in the root part and the Ph is high in the upper part, while in the 4 year-ginseng, most of the elements are high in the root part. Comparisons between contents of soil and ginsengs show similar in crease and decrese trends. However, the 2 year-ginsengs show clear differences between two areas while in the 4 year-ginseng, differences between the Gr and Ph is not clear. It suggest that the ginsengs absorb eligible element contents with ages, despite of clear content differences of the different soils. In the second attempt, the Gr shows high W, Pb, Th, U, Sn and B contents wlile Ph and Sh show high Ni, Cr, Co, Sc, V, As, Cu and Zn contents. In the comparisons between ages of the ginseng, regardless the area, most of the elements are high in the 2 year, especially in the Gr and Ph. In the comparisons of the areas, 2 year-ginsengs of the Gr show low contents in the most of the elements, and the S1 show higher Ni, V, Th and U contents than the Ph. 3 year-ginsengs of the Gr show low contents in the most of the elements, while the S1 show high contents in the most of elements. relative to the Ph. Comparisons between upper part and root part of the ginsengs show that in the ginseng, regardless the ages, the upper part is high. Comparisons between contents of soil and ginsengs show similar increase and decrese trends, and soil is low than the ginsengs in the most of the elements

• Geotechnical Engineering
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• v.6 no.1
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• pp.35-42
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• 1990

Over the years, most pavement designs based on soil strength and permanent strain are almost independent of soil elasticity. However, it was found that plasticity and elasticity of soil have both effected on the failure of pavement structures. The elasticity of soil, hence, using the resilient modulus is reflected for recent pavement design. Although the current AASHTO specifications(1986) for pavement design had changed the soil support value to the resilient modulus, triaxial devices conducting the resilient modulus test have not been fully equipped in a great majority of laboratories. Thus, in the present work, such a resilient modulus is usually derived(from CBR, K values, etc.) by estimating equations. The purpose of this study is to evaluate the resilient modulus of weathered granite soils sampled from 4 points of the central region of Korea by means of AASHTO T 274-82. According to this, some empirical equations for predicting that of the weathered granite soil are proposed and then, the relationship to convert CBR into the resilient modulus is developed.

• Journal of Radiation Protection and Research
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• v.16 no.1
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• pp.15-24
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• 1991

Radon-222 exhalation rate from several domestic building materials were experimentally measured by using radon cup method, in which a CR-39 plastic is used as a passive radon detector. The radon detection factor of CR-39 detector determined in a series of calibration experiments was $0.164{\pm}0.005(tracks\;cm^{-2}/Bq\;d\;m^{-3})$, which is consistent with those reported by other investigators. The radon exhalation rates of several building materials (brick, red brick, concrete block, granite plate, concrete floor and wall) ranges from $6.8{\times}10^{-6}\;(granite plate)\;to\;75.0{\times}10^{-6}Bq/m^2-sec(brick)$ with the increasing order of granite plate, red brick, concrete wall, concrete block, concrete floor and brick. It showed that the CR39 radon cup can be efficiently utilized in measuring the radon-222 gas exhalation rate from building materials.

• Economic and Environmental Geology
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• v.37 no.4
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• pp.383-389
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• 2004

Understanding flow pattern of water and solute in subsurface is essential for the reduction and prevention of contamination of soil and groundwater and for the investigation and remediation of contaminated site. The objective of this study is to examine the infiltration pattern in a soil developed from the Jurassic granite using (Brilliant Blue FCF $C_{37}H_{34}N_{2}Na_{2}O_{9}S_{3}$), the nonfluorescent and nontoxic food dye. All image processing was conducted using geographic image processing software, ER Mapper, Version 6.2. The dye coverage was determined by counting the stained pixels in the photographs (80${\times}$80cm, 80TEX>${\times}$5cm) for the vertical and horizontal view. A homogeneous matrix flow occurred in the A horizon with weak, medium granular structure and fingering at the interface of finer-textured A horizon and coarser-textured C horizon. Pegmatitic vein originated from the granite and plant root in C horizon induced preferential flow.

• Economic and Environmental Geology
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• v.26 no.3
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• pp.349-361
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• 1993

The granitic rocks in the study area are divided into the schist and gneiss complex, Yongdok pluton, Yonghae pluton and Onjong pluton by their texture, fabric and relationship to the adjacent rocks in the field, Schist and gneiss complex occurs as xenolith or roof pendant in the Yongdok, Yonghae and Onjong plutons. The Yongdok pluton occurs in association with pegmatite and aplite in many places of its pluton. In the field it is obviously clarified that the Yongdok pluton is unconformably overlay by the Cretaceous sedimentary rocks. The Yonghae and Onjong plutons are gradationally changed each other, and these plutons truncate both the Yongdok pluton and the Cretaceous sedimentary rocks. Petrographically, the Yongdok pluton consists of granodiorite and granite with minor quartz monzonite. The Yonghae pluton is composed of diorite, quartz diorite, tonalite, and granodiorite. The Onjong pluton also ranges granodiorite to granite. Both the Yongdok and Yonghae-Onjong plutons are different in the constituent minerals, such as alkali feld~par, myrmekite, mica, sphene and mafic minerals. This suggests that each pluton might have been different crystallization sequence and characteristically different gological history during the crystallization period. Iron/magnesium ratio in biotite and hornblende from both the Yongdok and Yonghae-Onjong plutons gradually decrease as the differentiation index increasing in the whole rock. The decrease of this ratio strongly depend on the increase of opaque mineral contents. From the results of chemistry in the whole rocks and some mafic minerals, it is suggest that the granite plutons of the two different geological ages would have been suffered the environment of high oxygen fugacity in the process of magmatic emplacement and during the crystallization period.

• The Journal of the Petrological Society of Korea
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• v.18 no.2
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• pp.171-179
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• 2009

LA-ICP-MS U-Pb zircon age was determined from the granite gneiss from Jeungsan-Pyeongwon area located to the west of Pyeongan Basin, North Korea, yielding concordant age of $1,873{\pm}19(2{\sigma})$Ma interpreted as Paleoproterozoic granitic magmatism. Considering relatively precise data reported recently using SHRIMP and LA-ICP-MS, ages around 1,870 Ma have been most frequently reported from Precambrian basement rocks of Korean peninsula, including Yeongnam, Gyeonggi, and Nangnim massifs altogether. Geologic events of this period are interpreted as not only granitic magmatism but also hightemperature regional metamorphism depending on their localities. The magmatic and regional metamorphic events of similar periods have also been reported from neighboring cratons of both North China and South China. Therefore, we need more data and efforts to decipher correlation between Precambrian basements between Korea and China.

• Tunnel and Underground Space
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• v.11 no.4
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• pp.352-361
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• 2001

Mode I fracture toughness ( $K_{IC}$) of the frozen rocks and that of the frozen-thawed rocks were obtained by using BDT and CCNBD specimens. The test temperatures ranged from +$25^{\circ}C$ to -16$0^{\circ}C$. Wet and air-dry specimens of granite and sandstone were used in order to investigate the effect of water and porosity on fracture toughness. The SEM images of the frozen-thawed rocks were also analysed to check the density of thermal cracks. The $K_{IC}$ of the frozen rocks increased as the test temperature went down. The rate of increase was higher in wet condition than in dry condition and the rate of increase for wet granite was higher than that for wet sandstone. The $K_{IC}$ of the frozen-thawed rocks varied within 15% from the $K_{IC}$ of the rocks at room temperature. After one freeze-thaw process, thermal crack occurred in granite but no thermal cracks occurred in sandstone. And the crack density was increased as the temperature went down.n.

• Tunnel and Underground Space
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• v.26 no.4
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• pp.327-337
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• 2016

In this study, laboratory hydraulic fracturing tests are carried out to evaluate the effects of the cleavage anisotropy of Pocheon granite. Breakdown pressure is smaller when cracks are generated to the direction of rift plane in constant pressurization rate condition because of higher microcracks density. Besides not only injection rate changes but also the amount of injection pressure for fracture initiation and crack expansion is detected while testing due to internal deformation. Pressurization rate is higher while hydraulic fracture testing with constant injection rate condition in case of the specimen which has rift plane perpendicular to borehole because there are much flow paths to penetrate compared to the specimen which has hardway plane perpendicular to borehole. Observation by X-ray CT scanning shows that almost all of cracks due to hydraulic fracturing are generated to the direction of plane which has higher microcrack density that is rift plane or grain plane.

• Economic and Environmental Geology
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• v.33 no.2
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• pp.147-163
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• 2000

The Buseok pluton in the Yeongju Batholith is a comagmatic plutonic rocks which haveconcentrically compositional zoning. The lithofacies of the Buseok pluton comprise hornblende biotite tonalite in the southern part of the pluton, porphyritic and equigranular biotite granodiorite in the northern part and biotite granite in the north-central part. The compositional variations change gradually with continuity both within and between the lithofacies. The concentrically zoned pattern is relatively mafic rocks composed of high-temperature mineral assemblages in margin of the southern part, passing inward and northward gradually to more felsic rock in core of the north-central part. Changes in the textures and microstructures, as well as in the mineral content, take place between rock types of the plutons. Darker colored, generally coarse-grained, well foliated tonalite pass inward to light colored, coarse-grained, poorly foliated granodiorite, and finally give way to lighter colored, medium-grained, nearly nonfoliated granite. The foliation are best developed in the marginal part of the tonalite. Here, the regional myolitic foliation in the tonalite is steep northward and parallels to its southeastern contact with the country rock, but the magmatic foliation from disc-shaped mafic microgranitoid enclaves is subvertical and parallels the contacts with the country rock. As the tonalite approaches biotite granite in composition, the foliation is indistinct. Modal and chemical data for the pluton show quantitative compositional variation from the margin of the southern part to the core of the north-central part. Quartz and K-feldspar increase toward the core of the pluton, whereas hornblende, biotite and color index decrease. /Abundances of $SiO_2$and $K_2O$$_2$O increase toward the core according to the variation in quartz and K-feldspar, whereas those of MnO, CaO, $TiO_2$, $Fe_2O_3$, MgO and $P_2O_5$ decrease corresponding to the variation in mafic and accessaries. The compositional zonation resulted from fractional crystallization involving downward settling of earlier crystals, accompanied by upward movement of melt and volatiles, and followed by accessary marginal accretion of crystalline material in the magma to the marginal part. Although a little crustal contamination by the wall rock is recognized from the isotope data, the contamination is not only dominated over but also appropriate for forming the compositional variation in the pluton.