• Economic and Environmental Geology
• /
• v.26 no.2
• /
• pp.155-166
• /
• 1993

Gold contents with major and trace elements have been determined in 67 fresh igneous and altered wall rocks in the acid-sulfate alteration zone of the Ogmaesan-Seongsan pyrophyllite deposits in the Haenam area of the south-western part of Korean peninsula. The results are as follows; (1) Li contents have a tendency to show high value in dickite and altered rocks with dickite, while As, Mo and Sb contents have tendencies to show high values in alunite vein and silicified zone. F contents are higher in the altered rocks compared to fresh rocks. (2) Gold contents are enriched in alunite vein and silicified zone of the Seongsan deposit, but depleted in dickite and altered rock with dickite. Gold contents are especially concentrated in fault or conjunction area of two faults. (3) Gold contents are higher values in the mineral assemblages of alunite-quartz-pyrite and alteration zone of the Seongsan deposit among the studied deposits. (4) Gold contents in samples of silicified zones tend to show positive correlations with Ag, As, Co, Hg, Sb and V content, but negative correlations with Y and Zr contents, while on the other gold contents of silicified tuffs tend to show positive correlations with Hg and Sb contents. Therefore it is important to survey alunite vein and silicified zone at the conjunction of faults, and to analyze pathfinder elements such as Ag, As, Hg and Sb for geological and geochemical exploration of gold in the studied deposits.

• Geophysics and Geophysical Exploration
• /
• v.7 no.1
• /
• pp.99-104
• /
• 2004

A combination of drilling, geophysical well logging, and electrical soundings was performed to evaluate seawater intrusion in Baeksu-eup, Youngkwang-gun, Korea. The survey area extends for over 24 $km^2$. To delineate the extent of seawater intrusion, 60 vertical electrical soundings (VES) have been carried out. Twelve wells were also drilled for the collection of hydrogeological, geochemical, and geophysical well logging data, to delineate the degree and vertical extent of seawater intrusion. To map the spatial distribution of seawater in this coastal aquifer, geophysical data and hydrogeochemical results were used, and the relation between the resistivity of groundwater and equivalent NaCl concentration was found. Layer parameters derived from VES data, various in-situ physical properties from geophysical well logging, and the estimated equivalent NaCl concentration were very useful for quantitative evaluation of seawater intrusion. Our approach for evaluating seawater intrusion can be considered a valuable attempt at enhancing the use of geophysical data.

• Spatial Information Research
• /
• v.19 no.4
• /
• pp.81-89
• /
• 2011

This paper presents a multivariate kriging algorithm that integrates categorical data as secondary data for spatial interpolation of sparsely sampled ground survey data. Instead of using constant mean values in each attribute of categorical data, disaggregated local mean values at target grid points are first estimated by area-to-point kriging and then are used as local mean values in simple kriging with local means. This algorithm is illustrated through a case study of spatial interpolation of a geochemical copper element with geological map data. Cross validation results indicates that the presented algorithm leads to significant respective improvement of 15% and 25% in prediction capability, compared with univariate ordinary kriging and conventional simple kriging with constant mean values. It is expected that the multivariate kriging algorithm applied in this study would be effectively applied for spatial interpolation with categorical data.

• Ocean and Polar Research
• /
• v.36 no.2
• /
• pp.179-187
• /
• 2014

Directly searching for undiscovered hydrothermal vent sites is inefficient due to the practical difficulty of comprehensively imaging vent fields. Thus, most searches for hydrothermal vent sites rely on the detection of hydrothermal plumes from water column observation. Detecting and measuring the hydrothermal plumes are the most efficient way to infer the presence and distribution of hydrothermal vents. Both the array of vertical casting and lateral towing are the most common methods to discover hydrothermal plumes. In this study, we compared results of cast and tow-yo operations along the same section of a spreading center with a distance of 20.5 km in the North Fiji Basin for mapping hydrothermal plumes. Operation of CTD tow-yo provides a detailed pattern of plumes which enable us to locate the hydrothermal vents. On the other hand, identification of hydrothermal activity can be determined effectively by CTD cast with additional analysis of geochemical tracers. Reduction in the operating time is another advantage of CTD cast operation, especially for regional-scale survey. Our results show that the combination of CTD cast and tow-yo would improve the efficiency of the hydrothermal plume survey to locate new hydrothermal vent sites.

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

• Journal of Conservation Science
• /
• v.30 no.2
• /
• pp.205-217
• /
• 2014

The stone artifacts in Bronze age from the Sinsongri sites in Seosan, Korea were studied on material characteristics and provenance presumptions. The use and rock names of the artifacts are a stone before processing, two semifinished stone arrowheads and a grinding stone plate by slates. In addition, there is semifinished stone arrowhead by andesitic rocks. The slate could be observed easily around the site, and the andesitic rock could be confirmed typical occurrences of the all kinds of rocks around the Kanwoldo and Hwangdori, Anmyun area above 10km from the site. As a result of analysis which is comparing between stone artifacts and same kinds of raw material rocks, the stone artifacts made by slates have similar lithology and geochemical characteristics however, the stone artifacts made by andesitic rocks are found a some different part of characteristics to the same kind of raw material rocks. Comparing of major, rare earth, compatible and incompatible elements about stones artifacts made by slates and by the same kinds of raw material rocks have same geochemical patterns. However stone artifacts made by andesites and the raw material rocks are confirmed some differences of geochemistry. Therefore the slate stone artifacts in Sinsongri site suggest that these are domestic-type which are made of the rocks around the site, and it was understood that the andesitic stone artifacts are foreign-type which need to get more geological survey and study about different volcanic artifacts of the site around the area.

• Economic and Environmental Geology
• /
• v.50 no.4
• /
• pp.313-324
• /
• 2017

Tsogttsetsii area, an intrusive complex associated with Cu mineralization, is located in the South Gobi, Mongolia. We performed the cross geochemical and extended exploration survey in Tsogttsetsii area. Cu mineralization in Tsogttsetsii area is porphyry Cu type related with alkali granite intruded in Late Carboniferous to Early Permian. In the concentrated occurring to malachite appears extensively prophylitic alteration zone having a chlorite and epidote. As results of the survey, Cu contents of potable XRF and of chemical composition for altered rocks ranges 1.08 to 18.3% in the 30 points and 1.08 to 32.9% in the 13 points, respectively. Ore minerals identified in XRD analysis and polarizing microscope that samples of copper oxides were composed mainly of malachite, azurite, permingeatite and cuprite and the other minerals are pyrite, chalcopyrite, pyrargyrite, dickite, calcite, chlorite and epidote. Mineralization can be considered occurring to selectively some granite of the surrounding aplite and faults in the only upper part coming up the hydrothermal solution of the remaining residual magma after the aplite intrusion.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.46 no.4
• /
• pp.424-436
• /
• 2013

Organic enrichment was investigated in surface sediments from the Yeoja and Gangjin Bays of Korea, which contain dense shellfish farms, in order to evaluate the contamination status and temporal changes in shellfish farming along these coasts. The degree of organic enrichment was determined using geochemical indicators (chemical oxygen demand, ignition loss, acid volatile sulfide, total organic carbon in sediments, and total nitrogen in sediments, ammonium and nitrate in pore water, and bioluminescence inhabitation for sediments). Temporal changes in organic enrichment conditions were detected by comparing our 2012 data to those previously reported from a survey conducted in 1999/2000. Organic enrichment was significantly higher in September than in May and July, in Gangjin Bay than in Yeoja Bay, and significantly higher in shellfish farms than in reference sites not used to culture shellfish. Ammonium concentrations in pore water were two orders of magnitude greater than nitrate concentrations, suggesting that these bays represent nitrogen-reducing environments.

• Economic and Environmental Geology
• /
• v.9 no.1
• /
• pp.45-73
• /
• 1976

This study has been made for the enlargement of a previous work of 1964 which was carried out by an author of this work emphasizing the stratigraphy, micropaleontology, depositional environment, and structural tectonics of the studied area. The stratigraphic sequences of the area are groupped into four units: (1) basement of Pre-Cretaceous, (2) lower sediments of Late Cretaceous, (3) upper sediments of Late Cretaceous and (4) igneous rocks of Late Cretaceous and Tertiary (?). The oldest rocks consisting of schists and gneisses of Pre-Cambrian and schistose granite' of Jurassic age are exposed at the base of this area on which the thick Cretaceous sediments were deposited. These old rocks are unconformably overlain by the lower sedimens of Late Cretaceous composed of three members, an alternation of black shale and tuffaceous sediments, fine tuff and rhyollite flow in ascending order. The oily material was found from the black shales of the alternation m"ember as semi-solid greaselike material, oily order and microscopic granular spherical material and oily stain. The lower sediments are also overlain, in low-angleunconfromity, by the 'upper sediments having three members, an alternation of volcanic conglomerate and andesitic tuff, rhyollitic tuff and andesite flow in the same order. The igneous suit of diabase, diorites, biotite granite, porphyritic granite and porphyries of the latest Cretaceous and small exposure of pitchstone of Tertiary (?) intruded into the pre-existed rocks above mentioned. Considerable amount of ostra- coda microfossils have been chemically extracted from the black shales of the lower sediments and the identification of the fossils suggests that the depositional environment of the sediments were under fresh or brackish water condition. The distribution of the geology and its tectonic data also suggest a combination of dome and basin structures in the area of San-i peninsula and Jin-do as shown in fig. 8. Between these two units an anticlinal structure was constructed. As a result of this study, a seismic survey in a district between U-su-yong and north coast of Jin-do is recommended to determine the underground features.

• Economic and Environmental Geology
• /
• v.33 no.4
• /
• pp.273-282
• /
• 2000

In order to investigate the extent and degree of arsenic and heavy metal contamination and the bioavailability of toxic elements around the abandoned mine in Korea, an environmental geochemical survey was undertaken in the Daduk mine. After appropriate preparation, tailings, soil, stream sediment, crop plant and fingernail samples were analysed for As, Cd, Cu, Pb and Zn by ICP-AES and ICP-MS. Elevated levels of 8,782 mg/kg As, 8.3 mg/kg Cd, 489 mg/kg Cu, 3,638 mg/kg Pb and 919 mg/kg Zn were found in tailings from the Daduk mine. These significant concentrations can impact on soils and sediments around the tailing ponds. Mean concentrations of As, Cd, Pb, Cu and Zn in soils are significantly higher than those in world average soil, especially for As and Pb. Element concentrations in sediments decrease with distance from the tailing ponds due to a dilution effect by the mixing of uncontaminated sediments. Arsenic and Cd are elevated in rice grains and stalks, and Cu and Zn concentrations in chinese cabbage, sesame and bean leaves are higher than the upper limit values for normal plant. Arsenic concentration in fingernails of farmers are higher than the normal level with a maximum value of 1.5 mg/kg. The post-ingestion bioavailability of toxic heavy metals in some paddy and farmland soils has been also investigated using the SBET (simple bioavailability extract test) method. The method utilises synthetic leaching fluids closelyanalogous to those of the human stomach. The quantities of As, Cd, Cu, Pb and Zn extracted from paddy soils after 1 hour indicated 15.9, 65.4, 46.2, 39.4 and 29.4% bioavailability, respectively and for farmland soils, 12.4, 26.0, 31.2, 29.3 and 19.4% bioavailability, respectively. The results of the SBET indicate that regular ingestion of soils by the local population could pose a potential health threat due to long-term toxic element exposure.