• Title/Summary/Keyword: Korean granite

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Mineralization of Hydrothermal Ore Deposits in Relation to Chemical Variation of the Cretaceous Granitoids in the Gyeongsang Basin (경상분지내 열수광상의 광화작용과 백악기 화강암류의 화학성분 변화와의 관계)

  • Lee, Jae Yeong;Lee, Jin Kook;Lee, In Ho;Kim, Sang Wook
    • Economic and Environmental Geology
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    • v.27 no.4
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    • pp.363-373
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    • 1994
  • The Cretaceous granitic rocks show differences in rock types and chemical compositions according to metallogenic provinces of copper, lead zinc and molybdenum in the Gyeongsang basin. Jindong granites are of granodiorite~quartz diorite~diorite in Cu-province; Makeunsan/Yucheon-Eonyang granites, granodiorite~granite in Pb Zn-province; Onjeongri-Yeonghae granites, granodiorite~quartz diorite in Mo-province, and there is a trend that productive masses are less differenciated than barren masses in Cu and Pb-Zn provinces whereas productive masses are more differenciated than barren masses in Mo province. Metallogenic provinces are distinguishable by variations of major and trace elements. The Cretaceous granitic rocks are highest in the content of Ca, Mg and other basic major elements and lowest in the content of K and Na in Cu provicne; the variation trends are vice versa in Pb-Zn province. Trace elements such as Rb and Sr show variations related to K and Ca, and metallogenic provinces are also distinguishable by their ratios. The granitic rocks of Mo province have intermediate content of major and trace elements, but are clearly distinguishable from Jindong granites and partly overlapped by Yucheon-Eonyang granites. Chlorine content in biotites is higher in a productive mass than in a barren mass in Cu province. Therefore, the mineralogical and chemical compositions are applicable as geochemical index to distinguish the types of mineralizaion, and productive and barren masses of the Cretaceous granitic rocks in the Gyeongsang basin.

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Geological Interpretation on the Cretaceous Strata in the Haenam Area, Chollanamdo, Korea (전남 해남지역에 분포한 백악기층의 지질해석)

  • Koh, Sang Mo;Chang, Ho Wan
    • Economic and Environmental Geology
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    • v.29 no.3
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    • pp.381-393
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    • 1996
  • Cretaceous volcanics and volcaniclastic sediments are abundantly distributed in the Haenam area located at the tip of the southwestern part of the Yongdong-Kwangju depression zone. The Cretaceous strata correlated with the Yuchon Group of the Kyongsang Supergroup are divided into three formations: Hwawon Formation, Uhangri Formation and Haenam Formation in ascending order. The stratovolcanic Hwawon Formation is mainly composed of andesite and andesitic pyroclastics. The Uhangri Formation is the lacustrine sedimentary deposit. The Haenam Formation is composed of Hwangsan tuff, Haenam tuff, Yongdang tuff, Seoho tuff, and also Acidic lava, both being formed by a cogenetic acidic volcanism. The topographic circular structure of the Cretaceous strata was controlled by the doming of Jurassic Sani granite. Cretaceous volcanism in the study area is characterized by the two stages of intermediate volcanic activity in Cenomanian to Albian, and acidic volcanic activity in Campanian to Coniacian.

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A comparison study on coupled thermal, hydraulic, and mechanical interactions associated with an underground radwaste repository within a faulted granitic rock mass (화강암반내 단층지역에 위한 지하 방사성폐기물 처분장 인접지역에서의 열-수리-역학적 연성거동 비교 연구)

  • 김진웅;배대석;강철형
    • The Journal of Engineering Geology
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    • v.11 no.3
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    • pp.255-267
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    • 2001
  • A comparison study is performed to understand the coupling behavior of the thermal, hydraulic, and mechanical interactions in the vicinity of an underground radwaste repository, assumed to be located at a depth of 500 m, within a granitic rock mass with a 58$^{\circ}$ dipping fault passing through the roof-wall intersection of the repository cavern. The two dimensional universal distinct element code, UDEC is used for the analysis. The model includes a granitic rock meas, a canister with PWR spent fuels surrounded by the compacted bentonite inside a deposition hole, and the mixed bentonite backfilled in the rest of the space within a repository cavern. The coupling behavior of hydromechanical, thermomechanical, and thermohydromechanical interaction has been studied and compared. The effect of the time-dependent decaying heat, from the radioactive materials in PWR spent fuels, on the repository and its surroundings has been studied. A steady state flow algorithm is used for the hydraulic analysis.

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A Study on Load Carrying Capacity of Ancient Stone Arch Bridge (고대 석조아치교량의 내하력에 관한 연구)

  • 정형식;황영철
    • Geotechnical Engineering
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    • v.8 no.4
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    • pp.31-40
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    • 1992
  • The arch of an ancient stone arch bridge consists of blocky stone blocks. For the purpose of estimation of load carrying capacity of a stone bridge, the mechanically frail discontinuities between stone blocks should be taken account of. Since the current way of analysis regards the stone arch as a continuous member, the characteristic of discontinuties is not considered. In this paper, an ancient stone arch bridge is analyzed and load carrying capacity is estimated by Finite Element Method with the discontinuties between blocks being modelled as interface elements. From the result of the study, it is shown that the load carrying capacity of a stone arch bridge is dependent of friction angle and shear stiffness between arch blocks rather than compressive strength of arch block itself and the stone arch bridge of granite is more influenced by shear stiffness than friction angle. The load carrying capacity of HONG bridge of HEUNG GUK temple analyzed in this paper is estimated as that of a third grade bridge.

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Geochronological Study on Gyeonggi Massif in Korea Peninsula by the Rb-Sr Method (경기편마암 복합체의 Rb-Sr 연대측정연구)

  • Seung Hwan Choo;Dong Hak Kim;Won Mok Jae
    • Nuclear Engineering and Technology
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    • v.15 no.1
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    • pp.23-32
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    • 1983
  • In the previous studies on Rb-Sr geochronology, Gyeonggi Massif was known as the oldest rock in Korea Peninsula but the detailed sequence of geochronology was not studied yet. In the present study, some of whole rock isochrons considered here can be geochronologically grouped as follows: The ages of leucocratic gneisses at Yangpyeong, and augen and banded gneisses at Anyang show 2200 to 2300 m.y. which may represent the time of the Massif formation or an igneous intrusion. The age of the granite gneiss distributed in Yangpyeong area shows about 1400 m.y., which apparently represents the intrusion time of the gneiss. The age of the extremely altered metamorphic rock shows about 500 m.y., which may represent the time of a Caledonian orogenic event probably with hydrothermal activities. The other episodic ages of 800 to 900 m.y. which was widely observed through the Massif, may represent the ages of Precambrian igneous activities or regional metamorphism in the Massif. It seems to be reasonable that the ages of 120 to 270 m.y. show the times of Mesozoic and Late Palaeozoic Plutonisms in the Massif.

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Velocity analysis of various granite and its impact on determination of weathering (화강암의 속도 분석과 풍화도 산정에 미치는 영향)

  • Lee, Jae-Sung;Keehm, Young-Seuk
    • 한국지구물리탐사학회:학술대회논문집
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    • 2008.10a
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    • pp.201-206
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    • 2008
  • Determining the coefficient of weathering(CW) for stone heritage plays very important role in investigation and conservation plan. In most case, CW is obtained from the empirical relation, which use the difference between sonic velocities of fresh and weathered rocks. In this paper, we measured sonic velocities for the samples from Iksan, Geochang, Wonju, Goesan and Chungju of which our stone heritages are made. We first investigate the uncertainty of velocity by portable measurement by comparing it to lab measurement. There were small difference, but we conclude that the difference is not major. However, the velocity of fresh rock differs significantly among samples: ranging from 3200 to 4400m/s. This cause a lot of error in CW estimation if we use typical fresh rock velocity as of 5000m/s. Thus accurate measurement of the velocity of fresh rock is crucial to CW estimation.

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A Pole-pole Electrical Survey for Groundwater (2극법 전기비저항 탐사에 의한 지하수탐사)

  • Cho Dong-heng;Jee Sang-keun
    • Geophysics and Geophysical Exploration
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    • v.3 no.3
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    • pp.88-93
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    • 2000
  • The present study may be summarized as follows. By means of a pole-pole electrical survey, major geological features, i.e, fresh rocks, fractured & weak & saturated rocks, fresh water bearing aquifer, were successfully delineated in the surveyed area of a granite region in Korea. The subsequent Schlumberger sounding and drilling confirmed the existence of the acquifer at 60 m depth as expected. But one more minor acquifer which does not show up in the resistivity depth section was met at 100 m depth. A simple forward modelling leads the authors to believe that any other electrode configuration, e.g., Wenner, Schlumberger, dipole-dipole, pole-dipole, would not detect the deeper aquifer. Under these circumstances, further studies remain to be done in connection with the spatial resolution in the vertical direction.

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A Study of the Construction Method for Soft Ground Reinforcement of Baekje Dynasty Based on the Low Swamp Remains in the Buyeo Area (백제시대 부여지역 저습지에 조성된 유적에서 나타나는 연약지반 개량공법 연구)

  • Cho, Weon-Chang
    • Journal of architectural history
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    • v.19 no.6
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    • pp.155-171
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    • 2010
  • King Seong carried out the large-scale construction transferring the capital from Wungjin (Gongju) to Sabi (Buyeo) in 538. But because most of the Buyeo area was the low swamp in the time, it needed above all to form a site before transferring the capital. Until recently, in addition to the scientific excavation, the relief excavations for the construction of new building or the formation of road were conducted on many sites in the Buyeo area. As a result, many remains which were formed on the low swamp including the temple site of Neungsan-ri, Dongna Castle, the remains of Ssangbuk-ri (280-5 Bukpo, Hyeonnaedeul) and the remains of Gua-ri were identified. Also in these remains, the various engineering construction methods irrespective of the nature of remains were used for the purpose of the soft ground reinforcement as follows: mattress method of construction, pile designation, stone alignment, filing of decomposed granite soil, culverts and storage tanks. Especially, the mattress method of construction and the pile designation are thought to be the traditional engineering construction method at least in that they are appeared since the Three Han Sates era. And these soft ground construction methods had an effect on the construction of reservoir in Japan at the time. In the future, the construction method for soft ground reinforcement shall be concerned and studied further in the architecture and the civil engineering as well as the archeology.

A Basic Research for the Development of Cleaning Agent for Stone Made Cultural Property (석조 문화재 보존 처리용 세정제 개발에 관한 기초연구)

  • Cho, Heon-young;Xia, Yong-mei
    • Journal of Conservation Science
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    • v.11 no.1 s.14
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    • pp.28-37
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    • 2002
  • The cleaning in conservation treatment of cultural heritage is very important process. For the best conservation treatment of cultural heritage, except having a good detergency, the cleaning agent must be able to keep the heritage from the secondary deposition and re-soiling, damage and etc. In this paper, the dust (lichen, algae, dust, etc.) on the surface of stone made heritage was treated with some kinds of solvents and analyzed with FT-IR to develop a cleaning agent for stone made cultural heritage. And the cleaning ability to the dust and the corrosion ratio to the granite of the cleaning agent was investigated. Nonionic surfactants were good for treatment of stone-made cultural heritage. The reason is that nonionic surfactants are stable in acidic solution, and possess low reactivity with the compound of stone and low possibility to the second contamination, and build up the reactivities of acids and oxidants. A new cleaning agent composed with $H_2O_2/HF/NP-10$ shows a good cleaning ability for the conservation treatment of stone made cultural heritage.

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An Example of Changed Design through the Face Mapping and Slope Analysis (절토사면 현황도 작성 및 분석에 따른 설계변경 사례연구)

  • Lee, Byung-Joo;Chae, Byung-Gon;Lee, Kyoung-Mi
    • The Journal of Engineering Geology
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    • v.24 no.1
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    • pp.137-146
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    • 2014
  • The geology of the study area which is located in Samkoe-dong, Dong-gu, Daejeon city comprises black slate, limestone, and pebble-bearing phyllitic rock as meta-sedimentary rocks; and biotite granite and quartz porphyry intrusions. Face mapping revealed sliding in three or four sites of contained coaly slate, where the dip of the foliation and other discontinuities is parallel to the surface slope. The cause of the slope sliding is this parallelism as well as the swelling of the coaly slate when wet. In contrast, the slop on the opposite side of the road is relatively stable because the dip of the foliation and other discontinuities are oblique or normal to the surface slope. To ensure slope stability, a cut-and-cover tunnel was designed and constructed for the new road.