• Economic and Environmental Geology
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• v.38 no.4 s.173
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• pp.421-434
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• 2005

Abstract Based onthe characteristics of Carlin-type gold deposit in Nevada district, a potential in Korea is evaluated to the Yemi area where is structurally controlled by folds and trust fault. The fault of high angles are combined with a more permeable rocks such as the Yemi breccia and laminated silty limestone. The pattern of enrichment factors for Tl, Sb, As, Ag, Pb, Zn, Cu, Mo and W of limestones in the southern area are geochemically similar with those reported from the Carlin-type Bold deposit. Moreover, the oxygen and carbon isotopes show a hydrothermal alteration is widely developed in this area. According to the result of geophysical interpretation, stable isotope, alteration mineralogy, geochemical study, and geological structure, this mineralized zone may be extended to the M direction, so a detailed systematic exploration is required to identify this alteration zone.

• Geophysics and Geophysical Exploration
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• v.3 no.1
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• pp.1-6
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• 2000

The 1 $km^2$ area studied is located in Sukchun-ri, Hwasung-koon, the southern part of Kyeonggi-do. Even though this site has been known as a contaminated area caused by seawater intrusions, geophysical and geochemical surveys have never been carried out at the site to determine the extent of the seawater contamination and to investigate whether the seawater intrusion is in progress. The purpose of this study is to determine the extent of seawater contamination and a preferred channel of the seawater intrusion using geophysical methods such as DC resistivity surveys with Schlumberger array and a dipole-dipole array. In order to determine whether the seawater intrusion is in progress in the area, DC resistivity monitoring with Schlumberger array was performed. According to the resistivity map obtained from the inversion of the resistivity data measured with Schlumberger array, the study area is divided into two districts as relatively lowly resistive (less than 30 ohm-m) and highly resistive (more than 30 ohm-m) areas. The distribution of the lowly resistive area is consistent with the distribution of the layer composed of clay minerals, and the resistivity of this layer decreases slowly as approaching to the old seashore. Hydrogeological analysis shows that the clay layer within a distance of about 200 m from the seashore has been already contaminated by sea-water and its electric conductivity is 8 times higher than that of the sand layer covered by the clay layer. According to the results of the 2-dimensional DC resistivity surveys with a dipole-dipole array, there are two preferred channels of the seawater intrusion in the site, and both the channels are in the NW-SE direction from the old seashore. The lowly resistive zone in the southern channel extends to a depth of 80 m. The DC resistivity monitoring with Schlumberger array was carried out along the preferred channel which has the low resistivity Bone (fracture zone) that extended to a depth of 80 m. The time series of apparent resistivity, measured at a distance of 260 m from the old coast line, fluctuates with a period of 12 hours. From these observations, it can be concluded that the seawater intrusion caused by tidal action is still in progress along the fractured zone interpreted by the DC resistivity surveys with a dipole-dipole array.

• Economic and Environmental Geology
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• v.54 no.3
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• pp.353-364
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• 2021

Since the mid-twentieth century, geology has gradually evolved as an interdisciplinary context in South Korea. The journal of Economic and Environmental Geology (EEG) has a long history of over 52 years and published interdisciplinary articles based on geology. In this study, we performed a literature review using topic modeling based on Latent Dirichlet Allocation (LDA), an unsupervised machine learning model, to identify geological topics, historical trends (classic topics and emerging topics), and association by analyzing titles, keywords, and abstracts of 2,571 publications in EEG during 1968-2020. The results showed that 8 topics ('petrology and geochemistry', 'hydrology and hydrogeology', 'economic geology', 'volcanology', 'soil contaminant and remediation', 'general and structural geology', 'geophysics and geophysical exploration', and 'clay mineral') were identified in the EEG. Before 1994, classic topics ('economic geology', 'volcanology', and 'general and structure geology') were dominant research trends. After 1994, emerging topics ('hydrology and hydrogeology', 'soil contaminant and remediation', 'clay mineral') have arisen, and its portion has gradually increased. The result of association analysis showed that EEG tends to be more comprehensive based on 'economic geology'. Our results provide understanding of how geological research topics branch out and merge with other fields using a useful literature review tool for geological research in South Korea.

• Korean Journal of Remote Sensing
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• v.38 no.5_3
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• pp.863-872
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• 2022

Rare earth elements (REEs) have been used as one of power tracers for understanding geological and environmental changes due to their similar physico-chemical properties. In this study, we investigated the characteristics of rare earth elements in atmospheric particulates(PM_2.5) collected in Beijing and Gwangju during January 2018. The total concentrations of REEs in the Beijing samples were about 16X higher than those in Gwangju samples, and both samples are enriched in light REE than heavy REE, up to 8-10 times. The Post Archean Australian Shale (PAAS)-normalized pattern showed that both samples are enriched in Eu, Tb, and Er, and displayed positive Eu but negative Ce anomalies. The elemental correlations indicate that both samples originated from China desert and Loess plateau as well as cities surrounding Beijing. This study suggests that REEs in PM_2.5 can be used as a powerful proxy of revealing the difference between China and Korea, and provide basic information on the source and transport of PM_2.5.

• The Journal of Natural Sciences
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• v.8 no.1
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• pp.87-92
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• 1995

In the Vicinity of the Sindae-dong waste disposal site in Taejon, the average Cu, pb and Zn concentrations in soils are higher than those in other Korean soils but these are not high enough to cause any harmful effect to human and animal through the crop plants. Copper, Pb and Zn are not detected in the groundwater samples and F, Cl, $NO_2$, $NO_3$ and $SO_4$ concentrations in groundwater samples are lower than drinking water standards. However, the pH of groundwater sample in site D is 5.58 which is not suitable for the drinking water. With the electric resistivity method, the water-containg layers are found in contaminated soils and the resistivity values are considerably low because of the dispersion of plume by the leak of leachates. According to the results from the magnetic survey method, the anomalous values of the total geomagnetic fields and their gradients are found in the sampling site of low resistivity and high trace element concentrations.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.142-142
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• 2010

일반적으로 기술융합이라는 용어는 IT, BT, NT 등 성격이 다른 큰 범주에서 기술간의 결합으로 인식되고 있다. 현재까지의 기술융합 연구들은 IT기술을 중심으로 한 융합과 관련 국가 정책에 관한 것이 대부분을 차지하고 있어 큰 기술 범주 위주에 국한되어 있다. 하지만 동일한 목적을 위해 수행하는 유사 기술영영에서의 기술융합 역시 기술혁신의 수단으로 간과할 수 없는 영역이다. 실제로 미국, 유럽 등의 선진국에서는 기술융합 전담기관을 신설하여 프로젝트 내의 기술간 융합에 관심을 갖고 있지만, 국내에서는 프로젝트 범위의 기술융합 가능성 및 실효성에 대한 연구가 부족한 실정이다. 이에 본 연구에서는 지식경제부에서 수행하는 가스하이드레이트 연구개발사업을 실증사례로 하여 프로젝트 범위의 기술 융합에 관하여 기술융합의 필요성, 적용가능성, 실효성에 초점을 맞추어 고찰하였다. 가스하이드레이트 개발 사업은 지식경제부 내 가스하이드레이트 개발사업단 주관으로 2005년에 시작되었으며 2014년까지 I 지역 탐사 및 시추, II 지역 탐사 및 시추, 시험생산의 3단계의 달성목표를 가지고 있다. 가스하이드레이트는 천연가스가 저온 고압 상태에서 물과 결합해 형성된 고체 에너지로 화석연료 고갈에 따라 이를 대체할 가장 유력한 청정에너지원으로 주목받고 있다. 현재 가스하이드레이트 개발사업단에서는 지구물리탐사분야 지질지화학분야 개발생산분야로 세부 기술모듈을 형성하여 목표달성을 위해 노력하고 있지만, 중과제간 교류가 부족한 상황으로 인해 목표달성을 위한 기술력의 확보 및 향후 상업생산에 대한 불확실성이 증가하고 있는 상황이다. 이와 같은 상황을 해결하기 위해서 기술개발 및 혁신의 수단인 기술융합의 필요성이 증가하고 있다. 기술혁신은 기초연구, 응용연구, 개발, 학습, 투자 등의 일련의 과정을 거쳐 경제적 성과와 사회적 영향을 만들어내는 개념으로 정의 할 수 있다. 기술혁신을 이루어내는 가장 중심적인 역할을 담당하는 기술융합은 2개 이상의 요소기술들이 결합하여 기술이 갖지 않는 새로운 기능을 발휘하는 기술혁신의 한 현상으로 정의할 수 있다. 기술융합은 21세기 초에 접어들어 급속하게 변화하는 양상을 보이며 예상보다 경제에 더 큰 영향을 미치고 있다. 가스하이드레이트 각 단계에서의 애로점을 극복하기 위한 기술혁신을 위해 지구물리탐사 지질지화학 개발생산분야간의 융합의 가능성 등을 타진해본 결과, 각 기술융합들을 기술융합 유형에 맞춰 분류할 수 있었으며 유형별 적용가능성과 기대효과 측면에서 비교분석을 수행하였다. 분석의 정밀도를 높이기 위하여 기술융합 유형에 대한 이론과 실제 가스하이드레이트 전문가들과의 설문을 통해 비교분석을 실시하였다. 가스하이드레이트 실증 사례에 대한 분석 결과, 기술융합 이론은 기존의 큰 기술범주뿐만 아니라 작은 범주에도 적용할 수 있으며, 필요성과 적용가능성, 실효성 면에서도 충분한 고찰을 통해 기술융합 이론의 적용 범위를 좁히면 더 많은 연구와 융합기술을 얻을 수 있다는 결론을 얻을 수 있다.

• The Journal of Engineering Geology
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• v.16 no.4 s.50
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• pp.455-463
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• 2006

The electrical resistivity prospecting method with dipole-dipole array was applied to the Mooreung landfill site in order to survey the existence of leachate around the landfill site. Moreover, if there is leachate within Mooreung landfill site, the analysis of potential pathways to exterior environments was tried. Within the landfill site, the over-all characteristics of the electrical resistivity anomalies suggest that the leachate induced from the landfill materials has infiltrated the basement rock and fill the pores of basement rock in some parts of the landfill site. The consistency of the anomaly locations (left part of each survey line), anomaly geometries, and absolute resistivity value of anomaly through the 3 survey lines suggests that the resistivity anomaly be connected from the upstream to the downstream and correspond to the leachate material. Finally, the result from the electrical resistivity survey line near the gateway of the landfill site suggests that some of the leachate induced from landfill material leaks to the exterior groundwater system. It is necessary that more surveys using both geochemical and geophysical methods should be performed to find out potential pathways and depths of the leachate more precisely.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.729-744
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• 2023

The value of lithium has significantly increased due to the rising demand for electric cars and batteries. Lithium is primarily found in pegmatites, hydrothermally altered tuffaceous clays, and continental brines. Globally, groundwater-fed salt lakes and oil field brines are attracting attention as major sources of lithium in continental brines, accounting for about 70% of global lithium production. Recently, deep groundwater, especially geothermal water, is also studied for a potential source of lithium. Lithium concentrations in deep groundwater can increase through substantial water-rock reaction and mixing with brines. For the exploration of lithim in deep groundwater, it is important to understand its origin and behavior. Therefore, based on a nationwide preliminary study on the hydrogeochemical characteristics and evolution of thermal groundwater in South Korea, this study aims to investigate the distribution of lithium in the deep groundwater environment and understand the geochemical factors that affect its concentration. A total of 555 thermal groundwater samples were classified into five hydrochemical types showing distinct hydrogeochemical evolution. To investigate the enrichment mechanism, samples (n = 56) with lithium concentrations exceeding the 90th percentile (0.94 mg/L) were studied in detail. Lithium concentrations varied depending upon the type, with Na(Ca)-Cl type being the highest, followed by Ca(Na)-SO₄ type and low-pH Ca(Na)-HCO₃ type. In the Ca(Na)-Cl type, lithium enrichment is due to reverse cation exchange due to seawater intrusion. The enrichment of dissolved lithium in the Ca(Na)-SO₄ type groundwater occurring in Cretaceous volcanic sedimentary basins is related to the occurrence of hydrothermally altered clay minerals and volcanic activities, while enriched lithium in the low-pH Ca(Na)-HCO₃ type groundwater is due to enhanced weathering of basement rocks by ascending deep CO₂. This reconnaissance geochemical study provides valuable insights into hydrogeochemical evolution and economic lithium exploration in deep geologic environments.

• 한국지구물리탐사학회:학술대회논문집
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• 2001.09a
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• pp.75-89
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• 2001

There are 334 coal mines and about 900 metal mines abandoned. The environmental problems such as acid mine drainage from adits etc. and the subsidence has occurred in the abandoned mines. In addition, soil has been contaminated by tailings. According to analysis of mine drainages, some of them from adits in the abandoned coal and metallic mines were acidic and polluted by heavy metals. Especially, water quality of coal mine drainages were different by areas. Treatment of mine drainage by conventional chemical treatment has the drawback because the operating cost is very expensive. The treatment system used in mine drainage is the natural treatment system such as anoxic limestone drain in adits and the constructed wetland. The method of reclamation for abandoned waste rocks and tailings impoundments are mainly landfilling.

• Geophysics and Geophysical Exploration
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• v.17 no.2
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• pp.58-65
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• 2014

We studied the source mechanisms of very-long-period event recorded at seismic station WIZ near White Island Volcano, New Zealand on August 4, 2012. Since seismic data at only one station were available, we conducted moment tensor inversion using three simplified models (explosion, crack, and pipe models). To constrain the moment tensor solution of seismic event, we computed synthetic data for each model to compare with observed data. Type and orientation for the best model is a crack at a depth of 1600 m with a dip of $80^{\circ}NE$ and a strike of $N80^{\circ}W$. We interpret that a deep explosion may have opened a crack for gases to escape, and the upward gas flow triggered the surface explosions four hours later as confirmed by a webcam. The interpretation based on moment tensor inversion is consistent with previous studies of geochemical data of the volcanic island.