• The Korean Journal of Quaternary Research
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• v.12 no.1
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• pp.63-76
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• 1998

한반도는 산악지형이 우세하기 때문에 늪지나 호수의 발달이 불량하다. 현재 소규모 의 자연늪지는 낙동가 하류지역에 분포하며 동해안을 따라 일부 해안지역에 발달하여 있을 뿐이다. 고산지역에도 소규모의 늪지가 최근에 발견되었는데 그중에서도 무제치늪이 국내의 가장 남동쪽에 위치하고 있다. 정족산 정상부를 향하여 4개의 늪지가 차례대로 발달하여있 는데 이들의 성인은 온도차이에 의한 기계적풍화와 암석 차이에 의한 화학적 풍화적작용의 결과로 해석된다, 이들의 형성시기는 제 2늪의 습원퇴적이 가장 오래되 지층으로서 100~ 105cm 심도에서 탄소동위원소 연대측정으로 5,960$\pm$110yr BP. 의결과를 보이고 있드며 제 1늪의 습원 퇴적은 지표로부터 64~69cm 심도의 토탄층 최하부 부분에서 1,785$\pm$120yr BP. 의 연대측정 결과를 확인하였다.

• Proceedings of the Speleological Society Conference
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• 1994.11a
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• pp.115-116
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• 1994

1. 서론 2. 동굴의 일반적 특성 1). 우리나라의 자연동굴에는 석회동굴과 화산동굴, 그리고 해식동굴이 주가 되고 있다. 2). 이 자연동굴들은 편재적으로 분포되고 있으며, 석회동굴은 반도부에. 화산동굴은 제주도에 해식동굴은 해안에 분포한다. 3). 대체로 석회동굴은 고기암층에서 형성되어 그 경관이 웅대한 것이 대부분이고 화산동굴은 용암의 유동성과 관계되어 장대한 것이 특징이다. 4). 석회동굴에서는 화려하고 웅대하나 그 규모가 큰 것이 적다고 하겠으나 화산동굴은 세계굴적인 규모인 동굴이 많다. 5). 특히 협재굴, 황금굴, 표선굴 등과 같은 것은 화산동굴이나 2차생성물이 발달되어 있는 특이한 동굴이다. 6). 동굴의 기온은 지표의 기온에 영향을 전혀 받지 않는 것은 아니나 대체로 경도와 해발고도에 관계되고 있다. 7). 하리절의 동굴내 기온의 차는, 높은 위치에 있는 동굴의 기온이 낮은 위치에 있는 동굴보다 그 기온이 높게 나타난다. 8월의 고씨굴은 $16^{\circ}C$ 기온으로 나타났는데 같은 날 용연굴의 기온은 $17^{\circ}C$로 나타났다. 8). 동굴입구에서 깊은 내부의 대기의 기온차는 동벽의 온도와 거의 비슷하게 된다. 즉. 그 지층의 구조암석인 석회암의 기온에 지배되며, 이 온도는 거의 지표의 년간 평균온도와 비슷하다.(중략)

• Geophysics and Geophysical Exploration
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• v.16 no.3
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• pp.180-189
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• 2013

Geophysical exploration is widely used to develop strategic mineral resources in the world because of its efficient method in detecting mineralized zones in the metallic ore deposit. It is important to understand the physical properties of the stratum so that geophysical data can be more accurately interpreted. This paper is to comprehend physical properties of the rock at the Gagok mine, a typical skarn deposit in Korea. Thus, laboratory tests were conducted on specimens of ore and host rocks which were collected from rock outcrops and drill cores at the Gagok mine. Using the measurement system of rock physical property, we investigated the density, magnetic susceptibility, resistivity, and spectral induced polarization. According to the results, all physical properties of specimens had wide differences depending on contents of ore minerals, which are formed by skarnization. Especially, using the chargeability and time constant from the calculated spectral induced polarization data by the Cole-Cole inversion, we could estimate the volume contents as well as the grain size of the sulfide minerals. Therefore, the spectral induced polarization technique may be considered a useful method when exploring metallic ore deposit with sulfide minerals.

• The Journal of the Petrological Society of Korea
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• v.7 no.2
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• pp.132-145
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• 1998

The coal-bearing siliciclastic rocks of the Lower Permian Jangseong Formation, Samcheog coalfield, represent a megacyclothem which shows cyclic repetitions of sandstone, shale, coaly shale, and coals. Petrographic, geochemical, and SEM studies for sandstone samples, and XRD analysis for clay minerals were carried out to understand diagenesis in the sandstones of the Jangseong Formation. The Jangseong sandstones are composed of 60% quartz (mainly monocrystalline quartz) and 36% clay matrix and cement with minor amounts of feldspar, lithic fragments and accessory minerals (less than 4%). Jangseong sandstones are classified mostly as quartzwackes and partly as lithic graywackes according to the scheme of Dott(1964). The textural relationships between authigenic minerals and cements in thin sections and SEM photomicrographs suggest the paragenetic sequence as follows; (1) mechanical compaction, (2) cementation by quartz overgrowth, (3) formation of authigenic clay minerals (illite, kaolinite), (4) dissolution of framework grains and development of secondary porosity, and (5) later-stage pore-filling by pyrophyllite. We propose that these diagenetic processes might be due to organic-inorganic interaction between the dominant framework grains and the formation water. The Al, Si ions and organic acid, derived from dewatering of interbedded organic-rich shale and coals, were transported into the Jangseong sandstones. This caused changes in the chemistry of the formation water of the sandstones, and resulted in overgrowth of quartz and precipitation of authigenic clay minerals of kaolinite and illite. The secondary pores, produced during dissolution of clay and framework grains by organic acid and $CO_2$ gas, were conduit for silica-rich solution into the Jangseong sandstones and the influx of silica-rich solution produced the late-stage pyrophyllite after the expanse of kaolinite. The origin of the solution that formed pyrophyllite is not likely to be the organic-rich formation water based on the observation of fracture-filling pyrophyllite in the Jangseong sandstones, but the process of pyrophyllite pore-filling was indirectly related to organic-inorganic interaction.

• The Journal of the Petrological Society of Korea
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• v.26 no.1
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• pp.73-82
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• 2017

We determined SHRIMP U-Pb ages of the detrital zircons separated from the Bangnim Group of the Pyeongchang area to constrain its depositional age. As the result, the minimum age group yielded $^{206}Pb/^{238}U$ age of $450.3{\pm}4.2Ma$ (n=3), suggesting depositional age younger than Late Ordovician. Therefore, the Bangnim Group cannot be a Precambrian sedimentary formation but is younger than Myobong Formation of the Early Paleozoic Joseon Supergroup of the Taebaeksan basin. Such a depositional age implies that the Bangnim Group and structurally overlying Jangsan Quartzite should be in fault contact, suggesting that the Jangsan Quartzite, Myobong Formation and Pungchon Limestone thrusted over the Bangnim Group. The zircon U-Pb age distribution pattern of the Bangnim Group resembles those of the Early Paleozoic Myobong and Sambangsan Formations of the Taebaeksan basin and seemingly Middle Paleozoic Daehyangsan Quartzite and the Taean Formation. However, detrital zircon U-Pb age patterns of the Late Paleozoic Pyeongan Supergroup are quite distinct from them, suggesting drastic change in provenance of the detrital zircon supply. Therefore, we suggest that the Bangnim Group was deposited before the Pyeongan Supergroup.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.459-470
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• 2008

Types of slope failure related to cut slope stability are interpreted through case analyses, and also factors affecting structurally controlled instability investigated, which are developed by geologic structures along a national road No. 25 across the Cheongwon and Boeun-Guns, Chungbuk. Engineering properties such as orientation, persistence, roughness and uniaxial compressive strength of joints are analyzed by square-inventory method in three areas with well-preserved outcrops. The study area is located in Ogcheon folded bet, and are composed of quartz-schist and quartzite in the Midongsan Formation and phyllite in the Ungyori Formation. Flexural beds by folding, schistosity and cleavage besides joints are developed due to slight metamorphism. Various types of joints developed by folding are formed such as strike-parallel, strike-perpendicular, wedge and wrench joint sets by both initially regional and later superposed folding. Factors of slope instability are created by crossing the orientations of joint, cleavage, bedding and slope one another. In the case that the orientation of a slope is coincident with one of beds, factors causing large-scale failure including plane failure are increased greatly. Also in the region that orientations of the slope and bed are crossed each other at high angle, only local and minor failures are shown in the slope.

• Journal of the Korean Society of Earth Science Education
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• v.6 no.1
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• pp.69-77
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• 2013

The study aims to figure out pre-service elementary teachers' knowledge understanding on 'stratum and rock' as well as teaching-learning types on the same topic. A total of 65 seniors in an advanced science education course at B University of Education joined the research to fulfill the purpose above. With PCK classification framework, the study examined pre-service teachers' knowledge understanding on 'stratum and rock' while it analyzed how the teachers would teach the given topic to students. The results of the study are presented as follows. First, it was observed that the pre-service elementary teachers have a great understanding on 'stratum and rock' that would be taught via a science textbook for elementary fourth graders. However, regarding terms in 'shale and limestone', they appeared to have a relatively short understanding. Second, PCK elements of the pre-service teachers related to 'stratum and rock' were analyzed and according to the results, the teachers would be interested in teaching model selecting in the teaching-learning strategy field while they would be well aware of how important it is for them to perform an experiment in a teaching process. The teachers also appeared to understand that the teacher question can be mutual complementary during class. However, it turned out that the teachers would have a very much low understanding on learners' prior knowledge as they particularly believe that learning could be significantly affected by the learners' perception level as well as their learning interest and motive. Third, the pre-service elementary teachers were told to design teaching plans on 'stratum and rock' so that the study could find out what learning-teaching methods the teachers would adopt to teach the topic. It was learned that the teachers would proceed with the class basically by giving the learners a descriptive explanation on the topic and also by using pictures and drawings to enhance the learners' understanding during the class.

• The Journal of the Petrological Society of Korea
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• v.24 no.2
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• pp.107-124
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• 2015

The 'Imjin System' (or Rimjin System) was established in 1962 as a new stratigraphic unit separated from the Upper Paleozoic Pyeongan System based on the discovery of brachiopods and echinoderms of possible Devonian age. Subsequent discoveries of the Middle Devonian charophytes confirmed the Devonian age of the system. The Imjin System is distributed in the Imjingang Belt between the Pyongnam Basin and the Gyeonggi Massif, spans from the eastern areas including Cholwon-gun of the Gangwon Province, Gumchon-gun, Phanmun-gun, and Tosan-gun of the Hwanghaebuk Province, to the western areas of Gangryong-gun and Ongjin-gun of the Hwanghaenam Province, and includes the Yeoncheon Group (metamorphic complex) to the south. Unlike the lower Paleozoic strata in the Pyongnam Basin which solely produce marine invertebrate fossils, the Imjin System yields diverse non-marine plant and algal fossils. Brachiopods of the system are similar to those from the Devonian of the South China Block and include taxa endemic to the platform, implying a close paleogeographic affinity to the South China Block. The Imjin System is generally considered as of Middle to Late Devonian in age, although there have been suggestions that the system is of the Middle Devonian to Carboniferous in age. North Korean workers postulated that the Imjin System was deposited in the current geographic position, where the "Imjin Sea" (an extension of the South China Platform) was located during the Devonian. The Imjin System displays strong local variations in stratigraphy and its thickness. It has recently been reported that the strata are repeated and overturned by thrust faults in many exposures. The Yeoncheon Group a southward extension of the Imjin System, also experienced intense tight folding and contractional deformation. Northward decrease in metamorphic grade within the system suggests that the northern part of the Gyeonggi Massif and the Imjingang Belt are probably an extension of the Dabie-Sulu Belt between the South China and Sino-Korean blocks, and the Imjin System is an remnant of accretion resulted from the collision between the two blocks. In order to understand tectonic evolution and Paleozoic paleogeography of eastern Asia, further studies on stratigraphic, sedimentologic and tectonic evolution of the Imjin System involving scientists from the two Koreas are urgently needed.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.561-572
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• 2021

Aggregate collection is taking place in many areas in Korea, resulting in large cut slopes or large amounts of cut rocks. If the development site for such aggregate collection is a stratum accompanied by sulfide minerals, Acid Rock Drainage (ARD) may occur, which may cause environmental pollution in the development site and surrounding areas. As a result of the study on forest aggregate samples, most of the samples were classified as acid-forming potential samples, and among them, some samples from Gwangju, Goyang, and Sokcho were classified as potential acid-generating samples. This can be expected to affect the quality of aggregates when a large amount of aggregate is used in the future. Therefore, it is judged that these forest aggregates need to be managed when they are used. By predicting the occurrence of ARD through the acid-generating ability test, it is expected that economic losses that may occur in the future can be reduced, and it is judged that the problem of surrounding environmental pollution can be further alleviated.

• Geophysics and Geophysical Exploration
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• v.22 no.1
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• pp.1-11
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• 2019

Well logging technologies are used to measure the physical properties of reservoirs through boreholes. These technologies have been utilized to understand reservoir characteristics, such as porosity, fluid saturation, etc., using equations based on rock physics models. The analysis of well logs is performed by selecting a reliable rock physics model adequate for reservoir conditions or characteristics, comparing the results using the Archie's equation or simandoux method, and determining the most feasible reservoir properties. In this study, we developed a joint inversion algorithm to estimate physical properties in shaly sandstone reservoirs based on the pre-existing algorithm for sandstone reservoirs. For this purpose, we proposed a rock physics model with respect to shale volume, constructed the Jacobian matrix, and performed the sensitivity analysis for understanding the relationship between well-logging data and rock properties. The joint inversion algorithm was implemented by adopting the least-squares method using probabilistic approach. The developed algorithm was applied to the well-logging data obtained from the Colony gas sandstone reservoir. The results were compared with the simandox method and the joint inversion algorithms of sand stone reservoirs.