• 자원환경지질
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• 제1권1호
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• pp.35-46
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• 1968

Some of geologists in Korea recently postlated that Okchon system previously known to be precambrian age was the metamorphosed sediments of post-Chosen (Ordovician and pre-Kyeongsang (late Jurassic to Cretaceous) periods, or even definitely of Triassic period simply on the basis of the fact that Okcheon system overlies the Great Limestone series of Chosen system of Camber-ordovician age, and of other few assumptions of minor importance. As a result of such correlation, thick series of metasediments and Okcheon system of unknown age were established in this particular region and vaguely correlated to Paleozoic and Mesozoic sediments. Recent study done by the author reveled that: 1) only the upper Okcheon bed of S. Nakamura was true Okcheon system, and the middle and lower Okcheon beds were excluded, because they were correlated to Cambrian and Permian sediments resfectively, 2) Sangnaeri, Seochangri, and rengam formations of unknown age, and Baekhwasan, Jobong, and Ihwaryeong formations of Okcheon system of also unknown age were the metamorphosed Yangdeok system of Cambrian age, all of these formations were differentiated by the previous workers and were equivalent to the middle Okcheon system of S. Nakamure, and. 3) These metamorphosed Yangdeok system overlaid apparently the Great Limestone series in forms of overthrust and klippe which were produced by the orogeny took place during post-Daedong and pre-Kyeongsang period (probably middle to the Jurassic). The Sobaeksan Range, folded mountain Chains was also formed by this orogeny. Thus, Okcheon system newly defined by the author is precambrain age and consists in ascending order of Kemyenogsan, Hyangsan dolomite, and Daehangsan quartzite formation which were previously classified into metasediments of unknown age, and Munjuri, and Hwangkanri, formations which were differentiated into Okcheon system unknown age by the previous workers, but are of reversed sequence. Myeongori and Bukrori formations of Okcheon System are regard by the author as part of Hwangkanri formation. Few other assumption of minor important taken by the previous workers as their positive evidences are carefully explained that they were misinterpreted.

• 지질공학
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• 제22권3호
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• pp.293-307
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• 2012

지구물리학적 현상을 이해하고 지반공학 관련 문제를 해결하기 위한 주요 요소로서 전단파속도가 강조되어 왔다. 특히, 내진설계와 내진성능평가를 위한 지반지진공학 분야에서 전단파속도의 중요성이 보편적으로 인지되고 있다. 국내 183개소 부지들에서의 다양한 현장 탄성파시험 수행을 통해 대상 조사 부지들에서의 대표적 지반 동적물성으로서의 깊이별 전단파속도 분포들을 결정하였다. 대상 부지들의 지하 토사와 암반 지층을 지반지진공학적 간편 활용을 위한 매립토, 퇴적토, 풍화토, 풍화암 및 기반암의 5 종류 지반지층으로 재분류하였다. 현장 탄성파시험의 전단파속도 분포들을 종합하여 5 종류 지반지층들의 평균적인 전단파속도 주상들을 도출하였으며, 이를 토대로 지진학 및 지반지진공학에서의 유용을 위한 각 지층별 대표 전단파속도 값을 도출하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.519-519
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• 2003

We performed a hydrochemical study on a total of 89 bedrock groundwaters collected from preexisting wells (30 to 300 m deep) in the Boeun area. Hydrochemical data showed significant variations in the area, due to varying degrees of anthropogenic pollution. The waters were mostly enriched in Ca and HCO$_3$ but locally contained significant concentrations of anthropogenic constituents in the general order of Cl >NO$_3$>SO$_4$. In particular, about 11% of the examined wells exceeded the drinking water standard with respect to nitrate. We consider that aquifers in the area are locally highly susceptible to the contamination related to agricultural activities. Diagrams showing the relationships between the summation of cations (∑cations) and the concentration of several anions with different origin (natural versus anthropogenic) were used to estimate the relative role of anthropogenic contamination. A good correlation was observed for the relationship between ∑cations and bicarbonate, indicating that water-rock interaction (namely, hydrolysis of silicate minerals) is most important to control the water quality. Thus, we made an assumption that the equivalent of dissolved cations for a water should be equal to the alkalinity, if the chemistry were controlled solely by a set of natural weathering reactions. If we excluded the equivalent quantities of cations and bicarbonate (natural origin) from the acquired data for each sample, the remainder therefore could be considered to reflect the degree of anthropogenic contamination. Finally, we performed a multiple regression approach for hydrochemical data using the ∑cations as a dependent variable and the concentration data of each anion (natural or anthropogenic) as an independent variable. Using this approach, we could estimate the relative roles of anthropogenic and natural processes. Rather than the conventional evaluation scheme based on water quality criteria, this approach will be more useful and reasonable for the evaluation of groundwater quality in a specific region and also can be used for planning appropriate protection and remedial actions.

• 한국제4기학회지
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• 제22권1호
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• pp.28-36
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• 2008

The present study has focused on the environmental changes and evidences for sedimentation in the Lake Khuvsgul catchment during the Holocene period, inferred from short core sediment (BO03) from the eastern shore of Borsog Bay, which were analyzed in order to review records of the Holocene climatic evolution and Holocene history in Northern Mongolia. For the purpose of reconstruction of natural phenomenon that occurred in the lake catchment system during the Holocene, physical and chemical properties including HCl-soluble material, biogenic silica, organic matter and grain size distribution of minerals in the core sediments have been analyzed in this study. The vertical variations in composition for these properties show distinctly that five lines of paleoenvironmental evidence occurred in the lake catchment during the Holocene. A modified age model resulting from AMS carbon dating for the BO03 core sediment shows timings of these environmental events at 9.5 Kyr BP, 8.0 Kyr BP, 5.6 Kyr BP and 3.2 Kyr BP, respectively. Paleoenvironmental changes in the Lake Khuvsgul catchment system during the Holocene highlight distinctive features of the hydrological regime and geomorphologic evolution in the lake catchment due to regional landscape and global climatic changes corresponding with the Holocene optimum and thermal optimum. In particular, the change of hydrologic regime based on the sedimentological evidence has been caused by not only overland flow due to melting water, but also base flow due to thick permafrost around Khuvsgul region.

• 자원환경지질
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• 제30권4호
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• pp.353-362
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• 1997

P wave velocities of core samples from the Pocheon granite were measured before and after applications of cyclic loading. Then. distribution of the pre-existing microcracks and microcracks developed due to the cyclic loading was investigated by analyzing P wave velocity anisotropies and microscopic observations from thin sections. Anisotropy constants were calculated with three different ways: (1) $C_A$ between the maximum and the minimum velocities, (2) $C_AI$ between velocities measured along the axial direction and the average of six velocities measured in the planes perpendicular to the loading axis (rift plane) and (3) $C_AII$ between the maximum and the minimum velocities measured in the plane perpendicular to the loading axis. Among anisotropy constants. $C_AI$ was the most effective anisotropy constant to identify the rift plane whose orientation is parallel to the pre-existing microcracks as well as the distribution of stress induced microcracks. $C_AI$ decreased after cyclic loading and the relationship between $C_AI$ and number of cycles shows comparatively coherent negative trends. indicating that stress induced microcracks are aligned perpendicular to the orientation of pre-existing microcracks and that the amounts are proportional to the number of loading cycles. The difference of anisotropy constants before and after cyclic loading was effective in delineating the level of cracks and we called it Induced Crack Index. Velocity measurements and microscopic observations show that anisotropy was caused mainly due to microcracks aligned to a particular direction.

• 자원환경지질
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• 제29권3호
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• pp.305-313
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• 1996

In order to investigate the extent and degree of Cd, Cu, Pb and Zn contamination affected by mining activities of the Dalsung Cu~W mine, sampling of stream sediments and waters has been undertaken up to 1.5 km downstream from the mine at 50~150 meter intervals. Analysis of the samples was carried out using ICP-AES for Cd, Cu, Pb and Zn. Physical and chemical properties of sediments (pH, organic matter contents, cation exchange capacity) and waters (pH, Eh and temperature) were also measured. The properties of the sediment samples were characterized by low pH (3.0~5.5), low organic matter contents (2~5%) and a moderate degree of cation exchange capacity (7~15 meq/100 g) with a high proportion of sand fraction. The pH values of water samples ranged from 3.0 to 5.0 and the Eh levels were in the range of 350~530 mV. Concentrations of Cd, Cu, Pb and Zn in the sediments averaged 3.2 mg/kg, 1,390 mg/kg, 451 mg/kg and 262 mg/kg with the range of 0.6~11.4 mg/kg, 15~3,800 mg/kg, 14~1,330 mg/kg and 63~1,060 mg/kg, respectively. Significant levels of the heavy metals were also found in the water samples with the range of $10{\sim}170{\mu}gCd/l$, $300{\sim}41,600{\mu}gCu/l$, $10{\sim}80{\mu}gPb/l$ and $700{\sim}15,400{\mu}gZn/l$. These elevated concentrations in the sediments and waters may be caused by the weathering of mine waste materials and their high solubilities under acidic and/or oxidizing conditions. Although metal concentrations in the samples decrease with the distance from the mine, heavy metal contamination of sediments and waters were also found at the 1.5 km downstream due to the mobile conditions of the heavy metals, with particular reference to Cd and Zn in stream waters.

• 자원환경지질
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• 제50권6호
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• pp.509-515
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• 2017

일반적으로 석영은 지각을 구성하는 광물 가운데 가장 많은 부분을 차지하고 있으며, 이러한 석영의 용해와 침전에 대한 이해는 암석의 풍화 매커니즘과 열수작용 및 변성환경에서의 암석과 물의 관계를 규명하는데 매우 중요한 역할을 한다. 본 논문에서는 석영의 용해와 침전에 영향을 미치는 다양한 물리화학적 환경을 수식을 이용해 재정리하였으며, 이전의 연구자들이 발표한 연구결과를 바탕으로 물리화학적 조건하에서의 석영 용해에 대해 이론적 접근을 실시하였다. 본 논문을 통해서 석영의 용해 및 침전이 다양한 환경에 영향을 받으며, 특히 이론적 접근을 통해서 석영에 작용된 압력보다는 주변의 pH 및 온도 조건에 더 큰 영향을 받는다는 것을 확인하였다.

• 지질공학
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• 제22권4호
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• pp.449-458
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• 2012

암반의 구조적 특성에 대한 확고한 이해는 지반구조물의 효과적인 설계 및 유지관리에 있어서 매우 중요한 요소이다. 이는 암반의 강도, 변형 및 수리지질학적 특성이 주로 암반에 존재하는 불연속면의 연결구조 특성에 좌우되기 때문이다. 그동안 암반의 구조적 특성에 대한 연구에 있어서 상당한 진전이 있었음에도 불구하고 불연속면 분포의 복잡성으로 인하여 암반의 삼차원적 구현 및 가시화에 기반한 지질공학적 해석은 드문 실정이다. 이 연구는 암반의 불연속면 및 불연속면의 연결구조를 삼차원적으로 구현하고 가시화하는 기법을 제시하였다. 이를 위하여 원판형으로 가정한 불연속면의 비선형 방정식을 유도하고 불연속면 교차선과 등가파이프의 위치를 산정할 수 있는 대수학적 알고리즘이 제시되었으며, 또한 연산과정을 수행하는 전산모듈이 작성되었다. 이 연구에서 개발한 불연속면 연결구조의 삼차원적 구현 및 가시화 기법은 불연속체 기반의 암반강도 및 변형성에 관한 연구 또는 수리지질학적 특성에 관한 연구를 수행함에 있어서 활용도가 높을 것으로 판단된다.

• 자원환경지질
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• 제29권6호
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• pp.665-676
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• 1996

안정적인 천연자원의 공급을 통해 오랫동안 국가산업화에 이바지해온 일본의 광산산업은 산업구조의 개편에 따라 하향추세를 맞아 현재는 세 곳의 주요 광산만이 가행중이다. 최근 경제사정의 변화로 새로운 비금속광상의 개발이 어려워짐에 따라 매장량과 품위에 있어 경제적 가치를 갖는 천열수금광상으로 관심이 옮겨가고 있는 추세이다. 1970년대 후반의 급격한 금가격 상승은 환태평양 지역의 천열수금광상에 대한 지질학적 정보와 이해를 증가시키는 역할을 했으며, 특히 판구조론의 확립과 더불어 지열수계와 화석천열수계의 대비라는 가장 중요한 발전이 이루어졌다. 1988년에는 광산협회에서 천열수금광상의 개발을 목표로 일본내 19개 지역의 탐사를 인가했으며, 1989년부터는 준정부기관인 금속광업국에서 이 지역들의 금탐사를 수행해왔다. 광상성인에 관한 신개념과 새로운 탐사기술로 유망한 금광화대가 발견되어 왔으며 개발이 진척된 곳은 홋카이도 북부의 세타지역과 큐슈 중부의 노야지역이다.

• 자원환경지질
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• 제54권1호
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• pp.137-150
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• 2021

서악동 마애여래삼존입상은 경주 선도산 정상부의 동남향에 조성된 통일신라시대의 거석불로 입지적 중요성과 함께 힘찬 아미타불상과 부드러운 협시보살의 조각수법이 매우 특징적이다. 특히 안산암질 암반에 불신을 새기고 흑운모화강암을 대좌로 장식한 아미타불상과 좌우 병렬식으로 배치된 알칼리 화강암으로 조성된 협시불은 석재의 색상 및 질감을 통해 석불의 위엄을 잘 표현하였다. 아미타불상은 암반에 형성된 절리로 인한 불연속면의 발달과 사면의 불안정성, 최상부에서 발생하는 식물의 근압에 의한 암반의 이완현상이 결부되어 손상이 가속되고 있다. 또한 절리와 균열 및 박리 등 불연속면의 증가로 인해 물성이 크게 저하되었으며 조류 및 지의류의 피복도가 높은 상태이다. 따라서 마애여래삼존입상에 발생한 손상정도는 아미타불상이 마애불로 조성되면서 나타난 물리적 풍화특성과 다양한 생물침해에 의해 손상이 가속화되는 것으로 판단된다.