• Geophysics and Geophysical Exploration
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• v.10 no.1
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• pp.37-43
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• 2007

The MH21 Research Consortium has conducted a high-resolution 3D seismic survey and a seafloor geochemical survey, to explore methane hydrate reservoirs in the eastern Nankai Trough, offshore Japan. Excellent geological information about shallow formations was obtained from the high-resolution 3D seismic survey, which was designed to image the shallow formations where methane hydrates exist. The information is useful in constructing a geological and geochemical model, and especially to understand the complex geology of seafloor, including geochemical manifestations and the structure of migration conduits for methane gas or methane-bearing fluid. By comparing methane seep sites observed by submersibles with seismic sections, some significant relationships between methane hydrate reservoirs, free gas accumulations below the seafloor, and seafloor manifestations are recognised. Bathymetric charts and seafloor reflection amplitude maps, constructed from seismic reflections from the seafloor, are also useful in understanding the relationships over a vast area. A new geochemical seafloor survey targeted by these maps is required. The relationships between methane hydrate reservoirs and seafloor manifestations are becoming clearer from interpretation of high-resolution 3D seismic data. The MH21 Research Consortium will continue to conduct seafloor geochemical surveys based on the geological and geochemical model constructed from high-resolution 3D seismic data analysis. In this paper, we introduce a basis for exploration of methane hydrate reservoirs in Japan by fusion of 3D seismic exploration and seafloor geochemical surveys.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.173-184
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• 2004

The geochemical exploration was carried out of the soil systems in the survey areas(Mt. Subang area). The chemical values of soil samples for soil in this area are defined such as over values of Ag : 11 ppm(Average ： 1.91 ppm), Au 548 ppb(Average 42.39 ppb), Cu : 89 ppm(Average：51.40 ppm), Pb：190 ppm(Average ： 23.69 ppm), Zn : 157 ppm(Average : 61.78 ppm), respectively. Anomalous areas for each element have been chosen based on the factors such as, geologic settings, geochemical survey, chemical analysis of ore, chemical analysis of soil. statistical processing of the chemical analysis. Therefore, multi-elements anomalies area were recognized in the east-center part of the study area.

• Geophysics and Geophysical Exploration
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• v.8 no.2
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• pp.137-144
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• 2005

In this study, we offered the results of geophysical and geochemical survey on the municipal waste disposal area to delineate the size and extent of leachate contamination. Preliminary to intensive geochemical investigation, we performed two geophysical methods to characterize the survey area. Electromagnetic (EM) and magnetic method were used far site investigation. From the EM method, we can get the information of soil conductivity directly related to the leachate of the contaminations and from magnetic anomalies we can find the boundary of landfill which is not identified on the surface due to soil capping. The results of geophysical survey were well matched to those of geochemical method carried out inside and near the landfill. Electric conductivity (EC) of the groundwater sampled from low resistivity anomaly region of EM result was higher than background value and the border estimated from the magnetic survey showed good agreement with that estimated from the soil gas detection survey.

• Economic and Environmental Geology
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• v.41 no.5
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• pp.563-575
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• 2008

The ore depositional and geochemical exploration on Bougouni area in Mali, central-western Africa covering $2,000\;Km^2$ was conducted for determining the detailed survey area. According to the results of this exploration, the highly potential area for the zinc-tin-gold-silver mineralization was found in Kolani and Riarako areas. The contents of zinc in heavy sand collected in the stream sediments range from 14 to 8,600 ppm, while the mean values of zinc in this area are 543 ppm with threshold($x+2{\sigma}$) of zinc anomalies being 1,000 ppm in Bougouni area. Generally zinc anomalies are associated with the tin and molybdenum anomalies and hence the anomalous area was selected for the detailed survey area for tracing the primary zinc and precious ore deposits related to these anomalies in following project.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.144-148
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• 2001

A geophysical and geochemical study was performed to verify the depth of landfill as well as the horizontal/vertical distribution of leachate at the landfill site located in Gongju. The electrical resistivity, with dipole-dipole array and dipole spacing of 5m, was applied along the nine survey lines and electromagnetic induction survey was conducted along the perimeter traverse surrounding the landfill. Cations, anions and stable isotope ($\delta$D and $\delta$$^{18}$ O) analyses were performed on about 63 water and leachate samples collected in dry and rainy seasons at 31 sites. The result of electromagnetic induction survey make it possible to derive the potential route of leachate in the past or present. The imaging of processed resistivity field data show that the possible route of leachate doesn't exist except the survey line 7. The weak zone traversing the landfill, however, is revealed by the electrical resistivity imaging, which may be the potential route of leachate toward the deep ground. The geochemical data agree well with geophysical data for deducing possible route of leachate of the site.

• Economic and Environmental Geology
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• v.47 no.2
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• pp.147-168
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• 2014

The soil geochemical exploration was carried out targeting around Tri Le area far from about 30 km with northwestern direction from Que Phong within Nghe An province. The interval of sampling are horizontal 200 m interval with 23 line and longitudinal 300 m with 10 line, resulting in 228 soil samples. Based on the result of the soil geochemical exploration, the detailed pitting survey was carried out targeting the grid point with high TREO content, resulting in 75 soil samples within 7 pits. The geology of survey area are consisted of Ban Chieng biotite granite complex and granitic gneiss intruding Ban Khang formation comprising of quartz schist and marble. Main mineralization in the study area have the characteristics of occurrence with tin, ruby and REE-bearing monazite and xenotime to be thought as occurring at the alteration zone of granite complex. In order to elucidate the source rock of monazite and xenotime confirmed from heavy sand, soil geochemical exploration was carried out. As a analysis result with ICP-MS on the soil samples from the soil geochemical exploration, total REE oxide content of background amount to about 2 times of crustal abundance, enriching the heavy rare earth(about 2 times) and light rare earth(about 1.5 times). As a analysis result with ICP-MS on the soil samples from the soil detailed pit survey, we only identified outcrop considering as economic weathered granite body at the grid point 1-10 pit among 7 pits. As a synthetic consideration on the soil geochemical exploration and detailed pit survey, we tentatively designated Tri Le area as no promising target for REE. In 2014, we have the plan to carry out the soil geochemical exploration targeting the extended economic REE ore body in Quy Chau as project area from 2011 to 2012.

• The Journal of Engineering Geology
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• v.28 no.2
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• pp.247-258
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• 2018

In the demonstration-scale offshore $CO_2$ storage project, the monitoring team studies geophysical and geochemical monitoring of $CO_2$ injections in the Yeongil Bay, in which a $CO_2$ test injection (about 100t) was performed in January, 2017 and further injections in larger scales are planned for 2018 and 2019. In this study, the development status of the Korea-type Hydro-Geophone OBS (Ocean Bottom Sensor) and the geochemical baseline survey (focused on some anions of sediment pore water) are suggested as the preliminary results of the pre-injection test.

• Economic and Environmental Geology
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• v.45 no.6
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• pp.599-622
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• 2012

The phase I soil geochemical exploration was carried out targeting around Chau Binh area far from about 14 km with southeastern direction from Quy Chau within Nghe An province. The interval of sampling are horizontal 300 m with 14 line and longitudinal 500 m with 15 line, resulting in 194 soil samples. Based on the result of the phase I soil geochemical exploration, the phase II detailed pitting survey was carried out targeting the grid point with high TREO content, resulting in 56 soil samples within 7 pits. The geology of survey area are consisted of Ban Chieng biotite granite complex and Dai Loc gneissic granite complex intruding Bu Khang formation comprising of schist, gneiss and limestone. Main mineralization in the study area have the characteristics of occurrence with tin, ruby and REE-bearing monazite(about 300 g/t) and xenotime(about 10 g/t) to be thought as occurring at the alteration zone of granite complex. In order to elucidate the source rock of monazite and xenotime confirmed from heavy sand, soil geochemical exploration was carried out. As a analysis result with ICP-MS on the soil samples from the phase I soil geochemical exploration, total REE oxide content of background amount to about 2 times of crustal abundance, enriching the heavy rare earth(about 2 times) and light rare earth(about 1.84 times). As a analysis result with ICP-MS on the soil samples from the phase II soil detailed pit survey, we identified outcrop considering as economic ore body at the grid point 4-7 pit with N40W attitude. As a synthetic consideration on the phase I soil geochemical exploration and phase II detailed pit survey, we tentatively designated areas considering as the extension of economic ore body with REE anomaly. In the near future, we have the plan to carry out the geophysical exploration and test drilling targeting the interval anticipated to the economic ore body.

• Journal of Environmental Impact Assessment
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• v.9 no.1
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• pp.1-11
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• 2000

An environmental geochemical survey of heavy metal distribution in marine surface sediments around the ocean of Samcheonpo coal-fired power plant was conducted to investigate the possibility of coal-ash leakage from ash pond and the associated heavy metal pollution in sedimental deposits due to the operation of the coal-fired power plant. The X-Ray Diffractometry (XRD) analysis showed that the main leakage point of coal-ash was limited to a single site of the first ash pond. It also appeared that the amounts of organic carbon and metal elements were positively correlated to the grain size distribution, and that Co, Cr, Cu, Fe, Ni, and Zn were bounded to organic ligands. However, the distributions of Cd, Hg, and Mn did not have any significant correlation with the sediment grain size and organic matters. In particular, the distribution of Cd appeared to be affected by the concentration of the carbonate materials in the study area.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.1-10
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• 2011

The geology of the Pacitan district which occupies Southern mountain zone in the southwestern margin of East Java, Indonesia, consists of a pile of clastics and pyroclastics grading upwards into a series of sediments of Middle Miocene age which are intruded by a number of quartz porphyries and subvolcanic dacitic to andesitic bodies in after that time. The geochemical exploration in the Pacitan district to find out anomalous areas related with metallic mineral dispersion from the concealed ore deposits had been carried out using traditional exploration techniques of geological mapping, stream sediment, panned concentrate and outcrop sampling. The anomalous zones of each element were detected in the following areas: Gempol for Cu; Jompong for Au; Kasihan for Cu-Pb-Zn. The strongest Cu-Pb-Zn anomalous values are overlapped at the Kasihan area. The geochemical survey of soil was conducted with the geological survey at the Kasihan area. The statistical values were calculated by the statistical analysis method. The patterns for Cu, Pb and Zn are similar to the normal distribution. The anomalous values of copper-lead-zinc and/or copper and zinc are overlapped at five zones surrounding quartz porphyry at the central part of the Kasihan area. The area was interpreted and chosen as an anomalous zone related with stockwork and skam mineralization, extending to approximately NNW-SSE direction.