• Economic and Environmental Geology
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• v.56 no.5
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• pp.581-588
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• 2023

This study reports depth-dependent elemental distribution and mineral abundance of the oceanic sediment sample (WP21GPC04) near the Mariana Trench collected during the WP21 expedition in 2021. The elemental distribution determined by μ-XRF shows no significant differences with varying depth, with an average SiO₂ 53.91 wt%, FeO 4.48 wt%, Al₂O₃ 16.56 wt%, MgO 2.56 wt%, CaO 4.79 wt%, Na₂O 3.52 wt%, K₂O 5.48 wt%, similar to the average chemical composition of global subducting sediments (GLOSS). The mineral abundances analyzed using synchrotron XRD, however, vary with depth. While quartz, mica, and plagioclase were identified at all depths, chlorite was found at shallow depths, and zeolite group minerals, phillipsite and heulandite, showed a gradual change in phase fraction with depth. This suggests a change in sedimentation and alteration environments in the region, or the potential for coexistence emerges due to similar sediment stability. Overall, this study will provide a basis for the future investigations on the evolution of sedimentary environment near the Mariana Trench in the western Pacific Ocean and the phase distribution and the behavior of subducting oceanic sediments, which will affect the lithological and geochemical characteristics of the Mariana susduction system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1C
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• pp.7-15
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• 2010

In case that the seepage of contaminants into the subsurface has been generated from the waste impoundment by demage of geomembrane liner, it is necessary to repair the leaks of geomembrane liner for minimizing the environmental contamination by electrophoresis method. However, when electrophoresis method is applied to leachate electrolyte system, the phenomenon of clay particles flocculation would be accelerated by the interaction between clay particles and specific chemicals in leachate. In addition, the gravitational settling behaviour would be induced superior to the electrophoretic migration behaviour. Eventually, the limitations of field applicability for using the electrophoresis method are appeared. Therefore, 1-D enhanced electrophoresis method is conducted to prevent the clay flocculation and accelerate the migration of clay particles separately. After the 1-D enhanced electrophoresis experiment, we can get the results that the deflocculation effect of clay particles is increased by electrical repulsion of polymer, which adsorbed in clay particle edge, in case of using PAA dispersing agent.

• Proceedings of the KSEEG Conference
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• 2001.05b
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• pp.42-63
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• 2001

The detail survey on the Songsanri tomb site including the Muryong royal tomb was carried out during the period from May 1 , 1996 to April 30, 1997. A quantitative analysis was tried to find changes of tomb itself since the excavation. Main subjects of the survey are to find out the cause of infiltration of rain water and groundwater into the tomb and the tomb site, monitoring of the movement of tomb structure and safety, removal method of the algae inside the tomb, and air controlling system to solve high humidity condition and dew inside the tomb. For these purposes, detail survery inside and outside the tombs using a electronic distance meter and small airplane, monitoring of temperature and humidity, geophysical exploration including electrical resistivity, geomagnetic, gravity and georadar methods, drilling, measurement of physical and chemical properties of drill core and measurement of groundwater permeability were conducted. We found that the center of the subsurface tomb and the center of soil mound on ground are different 4.5 meter and 5 meter for the 5th tomb and 7th tomb, respectively. The fact has caused unequal stress on the tomb structure. In the 7th tomb (the Muryong royal tomb), 435 bricks were broken out of 6025 bricks in 1972, but 1072 bricks are broken in 1996. The break rate has been increased about 250% for just 24 years. The break rate increased about 290% in the 6th tomb. The situation in 1996 is the result for just 24 years while the situation in 1972 was the result for about 1450 years. Status of breaking of bircks represents that a severe problem is undergoing. The eastern wall of the Muryong royal tomb is moving toward inside the tomb with the rate of 2.95 mm/myr in rainy season and 1.52 mm/myr in dry season. The frontal wall shows biggest movement in the 7th tomb having a rate of 2.05 mm/myr toward the passage way. The 6th tomb shows biggest movement among the three tombs having the rate of 7.44mm/myr and 3.61mm/myr toward east for the high break rate of bricks in the 6th tomb. Georadar section of the shallow soil layer represents several faults in the top soil layer of the 5th tomb and 7th tomb. Raninwater flew through faults tnto the tomb and nearby ground and high water content in nearby ground resulted in low resistance and high humidity inside tombs. High humidity inside tomb made a good condition for algae living with high temperature and moderate light source. The 6th tomb is most severe situation and the 7th tomb is the second in terms of algae living. Artificial change of the tomb environment since the excavation, infiltration of rain water and groundwater into the tombsite and bad drainage system had resulted in dangerous status for the tomb structure. Main cause for many problems including breaking of bricks, movement of tomb walls and algae living is infiltration of rainwater and groundwater into the tomb site. Therefore, protection of the tomb site from high water content should be carried out at first. Waterproofing method includes a cover system over the tomvsith using geotextile, clay layer and geomembrane and a deep trench which is 2 meter down to the base of the 5th tomb at the north of the tomv site. Decrease and balancing of soil weight above the tomb are also needed for the sfety of tomb structures. For the algae living inside tombs, we recommend to spray K101 which developed in this study on the surface of wall and then, exposure to ultraviolet light sources for 24 hours. Air controlling system should be changed to a constant temperature and humidity system for the 6th tomb and the 7th tomb. It seems to much better to place the system at frontal room and to ciculate cold air inside tombs to solve dew problem. Above mentioned preservation methods are suggested to give least changes to tomb site and to solve the most fundmental problems. Repairing should be planned in order and some special cares are needed for the safety of tombs in reparing work. Finally, a monitoring system measuring tilting of tomb walls, water content, groundwater level, temperature and humidity is required to monitor and to evaluate the repairing work.

• The Journal of Engineering Geology
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• v.18 no.4
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• pp.555-566
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• 2008

Hydrogeochemical study in Samseung area (Boeun, Chungbuk) and waterrock interaction experiment using rock samples from the area were performed to elucidate the fluoride source in groundwater and explaining geochemical behavior of fluoride ion. Fluoride concentration of public water supply mostly using groundwater in Boeun area was significantly higher in South Korea. The maximum fluoride concentration of the study area was 3.9 mg/L, and 23% of samples exceeded the Korean Drinking Water Standard of fluoride (1.5 mg/L). The average concentration of fluoride was 1.0 mg/L and median was 0.5 mg/L. Because of high skewness (1.3), median value is more appropriate to represent fluoride level of this area. The relationships between fluoride ion and geochemical parameters ($Na^+$, $HCO_3$, pH, etc.) indicated that the degree of waterrock interaction was not significant. However, high fluoride samples were observed in $NaHCO_3$ type on Piper's diagram. The negative relationship between fluoride and $NO_3$ ion which might originate from surface contaminants was obvious. These results indicate that fluoride ion in groundwater is geogenic origin. The source of fluoride was proved by waterrock interaction batch test. Fluoride concentration increased up to 1.2 mg/L after 96 hours of reaction between water and biotite granite. However, the relationship between well depth and fluoride ion, and groundwater age and fluoride ion was not clear. This indicates that fluoride ion is not correlated with degree of waterrock interaction in this area but local heterogeneity of fluoriderich minerals in granite terrain. High fluoride concentration in Boeun area seems to be correlated with distribution of permeable structures in hard rocks such as lineaments and faults of this area. This entails that the deep bedrock groundwater discharges through the permeable structures and mixed with shallow groundwater.

• Economic and Environmental Geology
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• v.51 no.1
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• pp.27-38
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• 2018

Groundwaters in different rock types (Mesozoic granite, Precambrian gneiss, and schist) of Ganghwa island, Incheon City were characterized by using naturally occurring radioactive materials (NORM) and hydrogeochemical constituents. For the study, groundwater samples from 69 wells had been collected over eight years. Statistical methods were applied to relate hydrogeochemical components and NORM in the groundwater samples. The groundwater samples belonged to $Ca(Na)-HCO_3$ types. The uranium concentrations in three groundwater samples exceeded 30 ug/L of United States Environmental Protection Agency (US EPA) maximum contaminant level (MCL). The radon concentrations in 28 groundwater samples exceeded 4,000 pCi/L (picocuries per Liter) of US EPA alternative maximum contaminant level (AMCL). Gross-alpha in all the groundwater samples did not exceed 15 pCi/L of US EPA MCL. The average concentrations of uranium and radon in groundwater were the highest in granite area, and then gneiss, schist areas in order. In schist area, the correlation coefficient (R) between radon and $HCO_3$ is -0.40 and R between uranium and $SO_4$ is 0.54. In gneiss area, the R between radon and uranium is 0.55 and the R between uranium and $SO_4$ is 0.41. According to factor analysis, each geological area shows different chemical characteristics. The statistical analysis of whole groundwater resulted in nearly no significant relationship among uranium, radon and chemical constituents. Subsequently, more detailed studies on hydrogeological, geochemical, and geological characteristics related to NORM are required to better understand the behavior and fate of NORM.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.16-16
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• 2018

2017년 겨울, 기록적인 한파로 인해 바다가 얼면서 인천 앞바다로 유빙이 유입되었다. 2013년 해상에서 유빙이 발견된 이후 약 5년만에 다시 유빙이 등장한 것이다. 중부청 소속 항공단 순찰결과에 따르면, 2018년 1월 12일 인천대교 인근 해상에서 최초로 발견된 이후 강화 연안, 영종도 북단 등 해상에서 광범위하고 불규칙한 형태로 유빙이 분포되어 있는 것으로 나타났다. 유빙의 문제점은 해상에서 선박의 안전운항을 저해하고 경비함정의 안전에 지장을 초래하며 기름 유출 시, 유출유의 거동 특성이 달라져 일반적인 방제방법의 적용이 곤란한 점이다. 이에 따라 해상에서의 해양오염사고 대응방안 마련을 위해 저온 및 유빙 유입 해상에서 유출유의 거동 특성을 알아보았다. 구분인자를 극한의 추위(Extreme Cold), 유빙(Pack Ice), 정착빙(Fast Ice) 3가지로 분류하여 기름의 성상변화 및 시사점을 살펴보고, 유출된 기름의 효율적 방제를 크게 3가지로 분류(기계적 봉쇄 및 회수, 화학적 분산제의 사용, 현장소각)하였다. 일반적인 방제장비를 저온 및 얼음분포 해상에서 사용 시 슬러시화 된 얼음으로 인해 유출유 회수가 어렵고, 동결온도에서 장비가 오작동할 우려가 있다. 이미 북유럽 국가에서는 극한의 추위와 얼음분포 해상에 특화된 방제장비를 도입하여 해양오염대비 대응을 하고 있다. 2003년 3월 발틱해에서 불법적으로 유출한 선저폐수를 특화 장비는 brush bucket 유회수기 이용 방제조치한 사례가 있으며, 2006년 5월 같은 장소에서 선박 침몰로 인한 기름 유출이 발생했을때도 brush bucket 유회수기 이용 방제조치를 하였다. 국내에도 이상 기후로 인해 기록적인 한파가 지속되면서 북극에서나 볼 법한 유빙들이 발견되고, 해양오염사고는 언제 어디서나 발생할 수 있으므로, 해양오염방제의 임무를 맡고 있는 국가기관으로써 특수한 환경까지도 고려하여 대응방안을 마련할 필요가 있다. 해양오염이 재난으로 인식되고 있는 상황에서, 그리고 지구온난화로 인한 이상기후변화가 지속되는 상황에서 겨울철 유빙 유입은 점점 더 많아질 수 있다. 본 연구에서는 자료나 방제경험이 부족하므로 일찌감치 북극항로 개발로 앞선 방제기술과 경험을 가지고 있는 북극이사회를 벤치마킹하여 관할 해역 특성에 맞는 대응방안을 고찰해 본다.

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.1
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• pp.41-53
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• 1997

Geochemical data of soil and water samples were presented in order to assess the environmental impart for drinking water sites. Microscopic observation of rock samples and physical and chemical analysis of soil and water samples were undertaken. The geology of study areas are classified into three groups such as granitic rocks, meta-sedimentary rocks and sedimentary rocks. Enrichment of heavy metals derived from those rocks is not found in this study areas. Soils were analyzed for Cu, Pb, Zn, Cd and Cr using AAS extracted by HNO$_3$+HClO$_4$ and 0.1 N HCl. Heavy metal concentrations in soils are within the range of those in uncontaminated soils. In comparison of metal contents extracted by 0.1 N HCl and HNO$_3$+HC1O$_4$, less than 10% of the heavy metals are present in the exchangeable fraction. In particular, an pollution index has been proposed to assess the degree of soil contamination. Pollution index in soils are between 0.03 and 0.47 therefore, soils are not polluted with heavy metals. Deep groundwaters within granitic rocks have been evolved into Na$\^$＋/-HCO$_3$$\^$-/ type, whereas other deep groundwaters evolved into Ca$\^$2＋/-HCO$_3$$\^$-/ type. The predominance of Na$\^$＋/ over Ca$\^$2＋/ in deep groundwaters within granitic rocks is a result of dissolution of plagioclase, but for sedimentary and meta-sedimentary rocks, dissolution of calcite is a dominant factor for their hydrogeochemistry. The pH, conductivity and contents of the most dissolved ions in the water increase with depth. Shallow groundwaters, however, are highly susceptible to pollution owing to agricultural activities, considering the fact that high contents of nitrate, chloride and potassium, and high K/Na ratio are observed in some shallow groundwaters. In a thermodynamic approach, most natural water samples are plotted within the stability fields of kaolinite and smectite. Therefore, microcline and other feldspars will alter to form clay minerals, such as kaolinite and smectite. From the modelling for water-rock interactions based on mass balance equation, models accord well with behavior of the ions and results of thermodynamic studies are derived.

• Journal of Conservation Science
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• v.26 no.3
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• pp.229-245
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• 2010

The pupose of this study was to identify the material characteristics, firing environments and making techniques for the jar coffins from the Oryangdong kiln site and the Ungokdong tomb site in Naju. All jar coffins had very similar physical, mineralogical and geochemical characteristics, although it was excavated from the different sites. The wall thickness of the jar coffins was about 2.3 to 5.3 cm. Under the microscopy, the jar coffins include a large quantity of various quartz with some microcrystalline and showed partly orthoclase and biotite. It is presumed that the mineral sherds added to maintain the thick wall and to control the percentage of contraction during drying and firing of jar coffins and it has contained about 11.4 to 19.8 %. Firing temperature of the jar coffins is estimated as 1,000 to $1,150^{\circ}C$. Also, all jar coffins and soils show similar geochemical behavior of elements and clay-mineralization degree within the site. This indicates making that the soil is probable to be a raw material of the jar coffins. But it shows different characteristics in major elements of soils which is collected at the kiln floor and the trench region of the Oryangdong kiln site because of the lack of quartz and feldspar in the soils. Therefore, it can use of the jar coffins making clay, if it goes through a simple special process such as mixing temper.

• Economic and Environmental Geology
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• v.53 no.3
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• pp.307-320
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• 2020

This study focuses on the raw material characteristics, including firing temperature and the similarity of clay body, and making techniques on the underwater ceramics from offshore of Taean Mado, the Republic of Korea. The ceramic specimens include various types of celadons, Buncheongwares and white porcelains with very similar physical characteristics. All the clay bodies composed of same mineral phases within mullite and quartz, while cristobalite were also found in some white porcelains. Also, the geochemical composition of the clay body shows regular behavior properties for all the elements consisting of the celadons and Buncheongwares. In contrast, the irregular properties of trace and incompatible elements were found in white porcelains. Therefore, it is presumed that the white porcelains were made using the clay body with different source from the celadons and Buncheongwares. Notably, some white porcelains in low Th content are assumed to be made with clay formed in a different environments. Meanwhile, most of the ceramics had gone through the firing of 1,200 to 1,300℃, with some celadons fired from 1,150℃ to 1,200℃. Also, it can be interpreted as some white porcelains were fired on even up to 1,500℃.

• Journal of the Korean Geotechnical Society
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• v.31 no.7
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• pp.53-63
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• 2015

For the success of future missions to the Moon and other similar cosmic environments, understanding and utilization of the lunar regolith has become essential. However, due to the scarcity and unaffordability of real lunar regolith on Earth, a number of lunar regolith simulants (e.g., JSC-1; NASA) have been developed for experimental purposes. However, Korea does not have its own lunar regolith, even though the country is planning to actively pursue lunar and space missions in the 2020s. Thus, this study has been conducted to develop a Korean lunar simulant prototype via basic feasibility attempts (e.g., raw material selection, particle size and chemical composition simulation). Finally, the first prototype of Korea's own lunar simulant has been obtained, and denominated as KLS-1.