• Title/Summary/Keyword: Korean granite

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Petrochemical Study on the Precambrian Granitic Rocks in the Basement Area of Hambaeg Basin (함백익지(咸白益地) 기반지역(基盤地域)에 분포(分布)하는 선(先)캠브리아 화강암질암류(花崗岩質岩類)의 암석화학적(岩石化學的) 연구(硏究))

  • Yun, Hyun Sao;Lee, Dai Sung
    • Economic and Environmental Geology
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    • v.19 no.1
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    • pp.35-55
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    • 1986
  • The area of this study is located in the Sang dong district, Youngwol Gun, Kangwon Do, where the Ogcheon fold belt comes into contact with the Ryongnam massif. The area is covered by the Precambrian metasedimentary rocks of Yulri Group in the south from the line of Ungyosan-Maebongsan-Jansan-Taebaegsan Mountains and by the Cambro-Ordovician sedimentary rocks of Choseon Supergroup in the north. The Choseon Supergroup unconformably overlies the Yulri group. Several granitic intrusives occur in the Precambrian and Cambro-Ordovician terrain. The purpose of this study is to clarify the geochronology, mineralogical composition, geochemical characteristics, petrogenesis and tectonic settings of the Precambrian granitic rocks, and to evaluate the P.T. conditions of granitic intrusions. The K/Ar ages obtained from the muscovite of Nonggeori Granite, Naedeogri granite and pegmatite intruded into the Yulri Group are Early Proterozoic ($1805{\pm}18Ma$ to $1642{\pm}23Ma$), and those from the migmatitic pegmatite are Late Carboniferous ($305{\pm}4Ma$), respectively. The Precambrian granitic rocks are characterized by the presence of muscovite, tourmaline and grey feldspar with faint lineation of mafic minerals. In terms of mineralogical and chemical composition, the granitic rocks are felsic, calc-alkalic, peraluminous and S-type (ilmenite-series). The geochemical characteristics of major and trace elements indicate that the granitic rocks belong to syn-collision setting at the compressional plate margin. They were formed by progressive melting of relatively homogeneous crustal materials under 1~3kb and $670^{\circ}{\sim}720^{\circ}C$ in aqueous fluid conditions, and the Naedeogri granite was more fractionated than the Nonggeori granite. During the Taebaeg disturbance, Nonggeori granite, Naedeogri granite and pegmatite were intruded and emplaced into the Yulri Group. Migmatitic pegmatite occurring in the southwestern area, however, gave much younger muscovite age than the pegmatite intruded into the Yulri Group in rest of the area did, that might be due to the regional metamorphism of the Post-Choseon disturbance. The Geodo granitic mass and the Imog granite were intruded during the Bulgugsa disturbance.

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Dynamic Characteristics of Decomposed Granite Soils by Changing Geoenvironment (지반환경 변화에 따른 화강토의 동적특성)

  • Lee, Jin-Soo;Lee, Kang-Il;Kim, Kyung-Jin
    • Journal of the Korean Geosynthetics Society
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    • v.13 no.1
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    • pp.41-52
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    • 2014
  • Decomposed granite soil is likely to lose its strength when exposed to air or water. Such a geomaterial is weathered by wetting-drying or freezing-melting. In this study, resonant column tests were conducted to figure out the dynamic characteristics of granite soil that has affected by environmental changes like weathering condition. The results show that wetting-drying weathering condition is the most affective parameter on the dynamic characteristics of granite soil. In the meantime, artificial weathering conditions such as freezing-melting has less affection at first and getting increase as the process repeats constantly.

Geochemistry of Groundwater in Limestone and Granite of Hwanggangri Fluorite Mineralized Area (황강리 형석 광화대내 석회암 및 화강암지역 지하수의 지구화학적 특성)

  • Hwang, Jeong
    • Journal of the Korean earth science society
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    • v.23 no.6
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    • pp.486-493
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    • 2002
  • Hydrogeochemical characteristics of groundwater from a limestone and granite area were studied in the Hwanggangri district, where important fluorite ore deposits are distributed. The geochemical properties of groundwater from limestone and granite are commonly characterized as Ca$^{2+}$-HCO$_3\;^-$ and (Ca$^{2+}$+Na$^+$)-HCO$_3\;^-$ type, respectively. Groundwater, contaminated by mine drainage water from the neighboring ore deposits, has not been observed yet. However, fluoride in groundwater exceeding the drinking water permission level is found in the wells located in a Cretaceous granite area. The concentrations of F in the groundwater show a positive relationship with the values of Na, HCO$_3$, Li and pH. This may suggest that the groundwater come from the decomposition of fluoride-bearing silicate minerals within highly differentiated granitic rocks.

Effect of Different Substrate Characteristics on Abundance and Community Structure of Epilithic Diatoms in Two First-Order Streams

  • Ishida, Noriko;Iyoda, Yumi;Mitamura, Osamu;Choi, Jun-Kil
    • Korean Journal of Ecology and Environment
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    • v.41 no.2
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    • pp.137-143
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    • 2008
  • The abundance and community structure of epilithic diatoms grown on different substrata were investigated in two first-order streams located in a limestone and granite area, north of the Suzuka Mountains in Central Japan. Experiments were conducted as follows: limestone and granite without algae were submerged in their own streambed or another stream station and incubated for seven weeks, while limestone and granite with algae were transferred to another stream station and incubated at the same time. The diatom biomass was consistently high in the lime-stone station experiments compared to those at the granite station. In addition, there was more diatom biomass on granite substrata than on the limestone substrata at both stations. The present results suggested that the difference in water chemistry including the major nutrient concentrations was the limiting factor for algal growth in these two streams; however, when the water chemistry was the same in each stream, the difference in substratum characteristics became the important factor affecting the diatom abundance. The diatom community grown on the transferred substrata with and without algae became similar to those grown on the original substrata in each stream during the incubation period. It was suggested that the effect of the substrata characteristics on the diatom community structure was rather small.

Analysis of Influence Factors Related to Failure Characteristics of Excavated Slopes ; A Case of Southern Kyounggi Area along the Nat과l Road (절취 사면의 파괴 특성과 관련된 영향 요인 분석 ; 경기도 남부 국도 사례)

  • 김정환;윤운상;최재원
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.277-284
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    • 1999
  • This study describes the influence factors related to slope failure pattern and dimension in the southern Kyounggi area. Intrusive and metamorphic rocks are distributed in the study area. Geological condition, rainfall property and slope geometry are influence on slope failure characteristics in the study we& Geological factors related to slope failure are rock type, geological structure and weathering condition. Because of deep soil (RS-CW) depth of granite region, circular failure type is major failure pattern in granite region. Almost granite slopes with circular or surface failure pattern are failed during heavy rainfall season. But typical wedge failure type related to geological structure factor is a main failure pattern of metamorphic rock slope. Additionally failure dimension is influenced by geological factors and several factors, i.e. natural slope condition, failure type, rainfall intensity and etc. failure height/width ratio and thickness/length ratio of granite slope are 0.88 and 0.23. But the ratios of metamorphic rock slope are 1.36 and 0.19.

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Application of Triaxial Compression Test for Disturbed Weathered Granite Soil (교란화강암풍화토에 삼축압축시험방법의 적용)

  • Ryu, Je-Soo;Kim, Young-Jin;Jeon, Woo-Jeong
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2002.10a
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    • pp.341-344
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    • 2002
  • This study, soil sampling includes disturbed weathered granite soils from 8 different sites and disturbed weathered non-granite soils from 5 sample sites, put a purpose on finding for a utility possibility and practical use in this study. As a result of this study, internal friction angle & cohesion indicate which are from re-mold of samples by compaction seem to be able to use a compared to an field data. It is considered that strength parameter of disturbed weathered granite soil in the field is a useful reference.

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A Prediction of Behavior of Compacted Granite Soils Based on the Elasto-Plastic Constitutive Model (탄,소성 구성모델을 이용한 다짐화강토의 응력-변형률 거동예측)

  • 이강일
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.40 no.2
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    • pp.148-158
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    • 1998
  • The aims of this study are to evaluate the application on the stress-strain behavior of granite Soil using Lade's double work hardening constitutive model based on the theories of elasticity and plasticity. From two different sites of construction work, two disturbed and compacted weathered granite samples which are different in partical size and degree of weathering respectively were obtained. The specimen employed were sampled at Iksan and Pochon in order to predict the constitutive model. Using the computer program based on the regression analysis, 11 soil parameters for the model were determined from the simple tests such as an isotropic compression-expansion test and a series of drained conventional triaxial tests. In conclusion, it is shown that Lade's double work hardening model gives the good applicability for processing of stress-strain, work-hardening, work-softening and soil dilatancy. Therefore, this model in its present form is applicable to the compacted decomposed granite soil.

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Application of Triaxial Compression Test for Disturbed Weathered Granite Soil (교란화강암풍화토에 대한 삼축압축시험방법의 적용)

  • Kim, Jin-Chul;Ryu, Je-Soo;Kim, Young-Jin;Jeon, Woo-Jeong
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2003.10a
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    • pp.211-214
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    • 2003
  • This study, soil sampling includes disturbed weathered granite soils from 8 different sites and disturbed weathered non-granite soils from 5 sample sites, put a purpose on finding for a utility possibility and practical use in this study. As a result of this study, internal friction angle & cohesion indicate which are from re-mold of samples by compaction seem to be able to use a compared to an field data. It is considered that strength parameter of disturbed weathered granite soil in the field is a useful reference.

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Evaluation of YasufukuYs Constitutive Model for Compacted Weathered Granite Soil (다짐풍화화강토에 대한 Yasufuku 구성모델의 평가)

  • ;;Li Guang Fan
    • Journal of the Korean Geotechnical Society
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    • v.15 no.5
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    • pp.43-55
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    • 1999
  • This study evaluated Yasufuku's constitutive model in terms of its capability to accurately consider the observed behavior of Iksan compacted weathered granite soil for various stress-paths. The strains calculated from the model are in reasonable agreement with those measured, but some discrepancies occur. The largest differences between measured and calculated strains occur for axial strain of proportional loading with increasing stress. Yasufuku's constitutive model can consider the observed behavior of Iksan compacted weathered granite soil with accuracy for conventional triaxial compression and for p'-constant loading with increasing stress ratio.

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A Study on the Characteristic and Reinforcement of Road Cut Slope all over the HanGye Pass (한계령 일대 도로절토사면 특성과 보강방안 연구)

  • Rhee, Jong-Hyun;Kim, Seung-Hyun;Lee, Jung-Yup;Koo, Ho-Bon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.676-680
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    • 2006
  • Many collapse of road cut slope consisted of representative granite of korea peninsula is happened by weathering progress. Chose hangye pass consisted of korea peninsula's representative granite style for this study. Purpose of this study is that consider suitable reinforcement of cut slope consisted of granite by analyzing characteristic of hangye pass vicinity road cut slope.

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