• Title/Summary/Keyword: geological origin

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FEM Electrical Resistivity Modeling in Cylindrical Coordinates (원통 좌표계에서의 전기비저항 유한요소 모델링)

  • Choi Wonseok;Kim Jung-Ho;Park KwonGyu;Kim Hak-Soo;Suh Jung-Hee
    • Geophysics and Geophysical Exploration
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    • v.5 no.3
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    • pp.206-216
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    • 2002
  • The finite element method (FEM), a powerful numerical modeling tool for solving various engineering problems, is frequently applied to three-dimensional (3-D) modeling thanks to its capability of discretizing and simulating the shape of model with finite number of elements. Considering the accuracy of the solution and computing time in modeling of engineering problems, it is preferable to construct physical continuity and simplify mesh system. Although there exist systematic mesh generation systems for arbitrary shaped model, it is hard to model a simple cylinder in terms of 3-D coordinate system especially in the vicinity of the central axis. In this study I adopt cylindrical coordinate system for modeling the 3-D model space and define the origin of the coordinates with mathematically clear coordinate transformation. Since we can simulate the whole space with hexahedral elements, the cylindrical coordinate system is effective in handling the 3-D model structure. The 3-D do resistivity modeling scheme developed in this study provides basie principle for borehole-to-surface resistivity survey, which can be a useful tool for the application to environmental problem.

Comparative Study on Material Characteristics of Joseon White Wares Excavated from Gangwon Wonju Province (강원 원주지역 조선백자의 재료학적 특성 비교연구)

  • Lee, Byeong Hoon;So, Myoung-Gi
    • Journal of Conservation Science
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    • v.33 no.4
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    • pp.225-239
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    • 2017
  • This study aimed to investigate the chemical properties and production techniques for white wares from the Gwirae-1ri 3rd, Songok-3ri 2nd kiln sites in Kangwon Wonju regions. Further, another aim was to determine the correlation among the materials used to produce the white wares. The analysis of white wares in Kangwon Wonju regions produced the following results. The excavated white wares were analyzed using the Seger formula, and all the samples showed similar clay sources ($RO_2:4.33-5.82$, $RO+R_2O:0.32-0.43$) and glaze sources. Moreover, the white wares were made of host rocks of the same geological origin, according to the results of the rare earth elements analysis. When the crystalline phases of the white wares were investigated via the XRD analysis, quartz and mullite were found in all the samples, and their proportions were similar to each other. Although the firing temperatures for the samples were different, most were fired at a temperature below $1,200^{\circ}C$, with some being fired at temperatures as low as $1,000{\pm}20^{\circ}C$.

Geological Environments and Deterioration Causes of the Buddhist Triad Cave in Gunwi, Korea (군위 삼존석굴의 지질환경과 훼손원인)

  • 황상구;김수정;이현우
    • Economic and Environmental Geology
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    • v.35 no.5
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    • pp.407-420
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    • 2002
  • The Buddhist Triad Cave in Gunwi (National treasure No. 109) consists of porphyritic biotite granite, and it has been deteriorated into microorganic smears, white films, brown rusts, granular decay, color changes, and joints by the same weathering factors as rain, moisture, temperature variation and microorganic living. Main origin is probably the rain that leaks into the cave along joints in Palgongsan granite, and then its moisture grows many microorganism and is frozen over during winter. The granites around the cave regularly develop two NEE and NWW joint sets that are conjugate to be a joint system. The NEE set extends far away with narrow joint spacings and affects the leakage of the rains, and is divided into 4 joint zones, among which J$_{m}$ and J$_{3}$ immediately affect the leaking water into the cave. An extensional Joint, in northern wall of the cave, was formed by toppling of the block between J$_{m}$and J$_{3}$joint zones from widening the Jm aperture by roots of a big pine tree, and passes through the J$_{m}$joint zone. This bypass allows no circulation of small rain, but a good circulation of heavy rain from influx to the cave for a long pathway. Many Joints and cracks, in the ceiling near the cave entrance, immediately get through the J$_3$ joint zone, and have a good circulation of small rain 10 mm. Both J$_{m}$and J$_{3}$ joint zones are, therefore, chief influxes that cause leakage of the rains.

Assessment of River Water Quality Contaminated by Abandoned Mine and Hot-Spring using Principal Component Analysis (주성분분석기법을 적용한 온천 및 폐광산 오염원에 대한 하천수질평가)

  • Lee Jae-Young;Sato Yuko;Kang Meea;Jeong Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.15 no.4 s.42
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    • pp.381-390
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    • 2005
  • S City depends on the T River as source water for water supply. Arsenic and boron from the hot-spring waste-water discharged from the hot-spring spa resort and emerging from the fractures of bedrock of the river have been prevalent contaminant of the T River water. This research was conducted to propose the simple and quick surrogate parameter for water quality management easily. And through making hexa-diagram of principal ions in the water samples, existing state of the water and influence of the human activity or geological origin can be figured out. As a results of characteristics of the T River water quality using principal component analysis, the contributory percentages of the 1st, 2nd and 3rd principal components were $40.80\%,\;21.40\%\;and\;11.31\%$, respectively. Therefore it was clarified that the quality of the T River water could be explained by these three principal components. Concentration of the chloride ion, which is one of the characteristics of the hot-spring water, was well correlated to both arsenic and boron concentrations. Hence concentrations of the arsenic and boron in the raw water of the water reatment plant can be predicted by the measurement of concentration of the chloride ion.

A Study on Chemical Composition and Firing Temperature of White Wares from the Guyre-2ri Kiln Sites, Wonju (원주 귀래2리 가마터 출토 백자의 화학조성과 소성온도 연구)

  • Lee, Byeong Hoon;So, Myoung-Gi
    • Journal of Conservation Science
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    • v.30 no.3
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    • pp.249-261
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    • 2014
  • This study aims to examine production technique of white wares from the Guyre-2ri 1st and 2nd kiln sites, Wonju, Gangwon Province and characteristics of the used materials, and to find a correlation among materials of the excavated white wares. X-ray fluorescence sequential spectroscopy(XRF), X-ray diffraction(XRD), Dilatometer and Inductively coupled plasma mass spectrometry(ICP-MS), Inductively coupled plasma automic emission spectrometer(ICP-AES) were applied to determine the chemical composition, crystalline phase of samples, firing temperatures, trace elements and rare earth elements. White wares from the Guyre-2ri kiln sites contained high contents of coloring oxides and fluxes. Though firing temperature of each sample was different, they were mostly fired at a temperature below $1200^{\circ}C$ and some of them experienced a low temperature of $1000^{\circ}C{\pm}20^{\circ}C$ and a high temperature above $1200^{\circ}C$. When analyzing body crystalline phases of the white wares using the XRD method, quartz and mullite were extracted from all the samples, and the proportions were similar to each other. When analyzing the excavated white wares using the Seger formula, also, all the samples showed similar clay sources and production techniques. Moreover, the white wares were made of host rocks of the same geological origin, according to the result of rare earth elements analysis.

The Geometric Characteristics of Landslides and Joint Characteristics in Gangneung Area (강릉지역 산사태의 기하학적 특성과 절리특성에 관한 연구)

  • Cho, Yong-Chan;Chang, Tae-Woo
    • The Journal of Engineering Geology
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    • v.16 no.4 s.50
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    • pp.437-453
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    • 2006
  • More than 3,000 landslides were occurred by torrential rains in Gangneung area due to the typhoon Rusa in 2002. In order to analyze the landslide origin and its geometric characteristics, 1,365 landslide data were collected from the field survey of Sacheon, Jumunjin, and Yeongok areas in which the intensive landslides took place. The average landslide size in the study area was composed of 10m width, 30m length, and $21^{\circ}{\sim}35^{\circ}$ slope angle, and the plane view of landslides A-type (i.e. wide shape of lower part) that contains approximately 50.5% of the landslides commonly occurred. In particular the area of Sacheon heavily damaged by mountain fires had more occurrence of landslides than other areas. The landslides of uniform tendency of slope direction were examined resulted from the contribution of topographic characteristics due to the weathering and wind direction during heavy rainfalls. In order to analyze the direction of joint, 249 orientation data were collected from the study area. The window method was employed to determine the characteristics of joint density in 51 locations of the study area. The results showed that many landslides occurred in the areas of joint density with the range of $0.05{\sim}0.1$.

Significance of Modern Analog Studies for Exploration and Development of Oil Sand (오일샌드 탐사 및 개발을 위한 현생유사퇴적환경 연구의 중요성)

  • Choi, Kyung-Sik
    • The Korean Journal of Petroleum Geology
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    • v.14 no.1
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    • pp.12-20
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    • 2008
  • Oil sands in Canada are representative example of unconventional resources whose reserve estimates are as large as those in Saudi Arabia. Typical reservoir rocks of oil sands consist of channel-related deposits formed in a tide-dominated depositional setting. The tidal deposits are commonly characterized by spatially complicated and heterogeneous properties. Successful engineering methods to develop oil sands require in-depth understanding in the spatial distribution of reservoir properties. Geological model for oil sand reservoir characterization can be built on the basis of comparative studies of ancient and modem analogues. In particular, modern analogue studies become increasingly indispensable, since they provide better understanding in the reservoir-rock forming process and more importantly in the external mechanism responsible for the reservoir heterogeneity. Tide-dominated environment along the west coast of Korea is considered as one of the most excellent modem analogues of oil-sand forming depositional environment. Korean tidal environment provides insights on the origin of mud breccia, facies and stratigraphic architecture which are key issues to the characterization of oil sand reservoirs.

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SHRIMP U-Pb Zircon Geochronology of the Guryong Group in Odesan Area, East Gyeonggi Massif, Korea: A new identification of Late Paleozoic Strata and Its Tectonic Implication (경기육괴 동부 오대산 지역의 구룡층군에 대한 SHRIMP U-Pb 저어콘 연대측정: 새로운 후기 고생대층의 인지와 지체구조적 의의)

  • Cho, Deung-Lyong
    • The Journal of the Petrological Society of Korea
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    • v.23 no.3
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    • pp.197-208
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    • 2014
  • Zircon separated from a biotite schist of the Guryong Group in Odesan area, eastern part of the Gyeonggi Massif in Korea were analysed for SHRIMP U-Pb ages. CL images display composite core-rim structures of the zircon, indicating an in-situ overgrowth of zircon through a high-grade metamorphism. The metamorphic zircon rims give a weighted mean age of $247{\pm}6Ma$. While the detrital zircon cores have zoning patterns and Th/U ratios indicative of a magmatic origin. Among 53 analyses from the cores, 46 data yield near concordant ages which are concentrated at $378{\pm}10Ma$ (n=9), $420{\pm}4Ma$ (n=6) and $1845{\pm}9Ma$ (n=18) with sporadic Neoproterozoic ($687{\pm}9Ma$) to late Archean ($2519{\pm}20Ma$) ages. The age data constraint sedimentation age of protolith of the Guryong Group, so far unknown, as late Paleozoic. The Guryong Group of this study is the first late Paleozoic strata reported from eastern Gyeonggi Massif, and its maximum depositional age (ca 378 Ma) is identical with those of the late Paleozoic strata in the southwestern Ogcheon Belt. The Triassic metamorphic age and abundant middle Paleozoic provenance (361~425 Ma) of the Guryong Group are similar with those reported from the Triassic collisional belt in central China. Thus this study indicates that the Odesan area would be an possible eastward extension of the Triassic collisional belt in central China.

Basic Lunar Topography and Geology for Space Scientists (우주과학자에게 필요한 달의 지형과 지질)

  • Kim, Yong Ha;Choi, Sung Hi;Yu, Yongjae;Kim, Kyeong Ja
    • Journal of Space Technology and Applications
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    • v.1 no.2
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    • pp.217-240
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    • 2021
  • Upon the human exploration era of the Moon, this paper introduces lunar topography and geologic fundamentals to space scientists. The origin of scientific terminology for the lunar topography was briefly summarized, and the extension of the current Korean terminology is suggested. Specifically, we suggest the most representative lunar topography that are useful to laymen as 1 ocean (Oceanus Procellarum), 10 maria (Mare Imbrium, Mare Serenitatis, Mare Tranuillitatis, Mare Nectaris, Mare Fecundatis, Mare Crisium, Mare Vaporium, Mare Cognitum, Mare Humorum, Mare Nubium), 6 great craters (Tyco, Copernicus, Kepler, Aristachus, Stebinus, Langrenus). We also suggest Korean terms for highland, maria, mountains, crater, rille, rima, graben, dome, lava tube, wrinkle ridge, trench, rupes, and regolith. In addition, we introduce the standard model for the lunar interior and typical rocks. According to the standard model on the basis of historical impact events, the lunar geological eras are classified as Pre-Nectarian, Nectarian, Imbrian, Erathostenesian, and Copernican in chronologic order. Finally, we summarize the latest discovery records on the water on the Moon, and introduce the concept of water extraction from the lunar soil, which is to be developed by the Korea Institute of Geoscience and Mineral Resources (KIGAM).

Scientific Examination of Quarries of the Stone Remains Excavated from the First Burial Site of King Jeongjo (전(傳) 정조대왕 초장지 출토 석물의 채석지에 대한 과학적 검토)

  • LEE Myeongseong;AHN Yubin;KIM Jiyoung
    • Korean Journal of Heritage: History & Science
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    • v.56 no.3
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    • pp.196-212
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    • 2023
  • This study identifies the origin of stone remains (pavement and banister stones) excavated from the first burial site of King Jeongjo through petro-mineralogical analysis in a quarry and examines the relationship with the stone remains from Geolleung (King Jeongjo's Tomb). The excavated stones from the first burial site of King Jeongjo are all light gray fine-grained biotite granite, and mainly contain quartz, feldspar, and biotite. The magnetic susceptibility of the stones ranges from 5.55 to 12.10 (average 7.00) (SI unit). According to old documents, the quarrying sites of the stones were Mts. Aengbong and Yeogisan (Godeung-dong District, Suwon), and we found a fine-grained biotite granite outcrop behind Mr. Aengbong (currently the site of Yeonggwang Apartment) with a geological survey, and it was petrologically similar to the stone remains from the first burial site. The magnetic susceptibility of the outcrop rocks was 5.15 to 7.24 (SI unit), and their petro-mineral and geochemical characteristics were found to be the same as those of the first buried site and Geolleung Tomb. It was confirmed that most of the stone elements in the first burial site were reused to build Geolleung Tomb while moving the grave. Only the pavement and banister stones seem to have been discarded in the first grave site without being transferred. This is because the size of the new burial mound became larger than the first grave during construction because Queen Hyoui (the consort of King Jeongjo) died and was buried together with the king in the same tomb, and the stone blocks did not fit a grave that size. With these research results, it was possible to compare and examine the old records and scientific analysis data, and they are expected to be used as basic source material in related research.