• Economic and Environmental Geology
• /
• v.46 no.4
• /
• pp.329-338
• /
• 2013

The objective of this study is to investigate the contents and seasonal variation of arsenic in soils and crop plant(rice) in paddy fields around the abandoned metal mines in Korea. The soils were extracted by various methods including aqua regia, 1 M $MgCl_2$, 0.01 M $CaCl_2$ and 0.05 M EDTA to evaluate the relationships between soils and crop plants(rice). According to correlation analysis, statistically significant correlation with the four methods(p<0.01) were found in soils extracted by various chemical solutions and arsenic contents in soils were decreased in the order of 1M $MgCl_2$ > 0.01M $CaCl_2$ > 0.05 M EDTA. Biological accumulation coefficients(BACs) of rice stalks were higher than those of rice grain, and the coefficients under reducing(August) environment were higher than those under oxidizing conditions(October). Assuming the rice consumption of 315 g/day by farm households in Korea, the amount of daily intake of arsenic were estimated to be 77.8 ${\mu}g/day$. The daily intake of arsenic from the rice estimates up to 65% of ADI(acceptable daily intake) that the FAO/WHO Joint Food Additive and Contaminants Committee has set to evaluate their safeties.

• Economic and Environmental Geology
• /
• v.48 no.4
• /
• pp.313-324
• /
• 2015

This study constructed a 3D geological model for Uggi Nuur Fe-Mn mineralization zone in Mongolia, and the 3D geological distribution is cross-analyzed with magnetic anomaly distribution to figure out relationship between ore zone and subsurface geology. As a result of 4 step 3D modeling procedures including geological cross section, surface modeling, foliation modeling and solid modeling, the geology of the both study area is bordered by faults in NW direction with Munguntessj formation being located in the west side of the fault while Yashill formation is located on the other side of the fault. Moreover, the strike direction of foliation in the both formation shows same directional pattern with the NW faults. The magnetic anomaly distribution reveals that higher anomaly values are concentrated to near the ground surface. The analyses of 3 dimensional distribution between subsurface geology and magnetic anomaly indicates that higher anomaly is mainly distributed over the Munguntessj formation as a elongated lens bodies whereas the magnetic anomaly is evenly found in the both of Munguntessj formation and Yashill formation in the study area 2. It infers that volcanic activities associated mineralization occurred during silurian period, and the mineralized zone is thought to be realigned along the geological structures caused by later stage tectonic activities.

• Economic and Environmental Geology
• /
• v.47 no.5
• /
• pp.517-532
• /
• 2014

The Munamdong Formation is a small scale sedimentary deposit which is located in Yuljeonri, Naemyeon, Hongcheon Gangwon-do. In order to understand the depositional environment and its sequential change in the formation, sedimentary facies analysis was conducted. The result indicates that the Munamdong Formation began to be deposited in alluvial fan system accompanying volcanic activity and gradually deposited in lake system. As well, U-Pb, K-Ar and $^{40}Ar/^{39}Ar$ ages are determined from the Munamdong Formation. The SHRIMP U-Pb Phanerozoic Eon age of the detrital zircons in the middle part of the Munamdong formation yields $229.8{\pm}2.5Ma$. The K-Ar and $^{40}Ar/^{39}Ar$ ages of the volcanic rock in the lowermost part of the Munamdong formation are $203.7{\pm}3.9Ma$ and $227.4{\pm}8.4Ma$ respectively. These results confirm that the Munamdong Formation was deposited during the Late Triassic, indicating that the basin might be formed due to post-collisional rifting or collapsing.

• Economic and Environmental Geology
• /
• v.47 no.5
• /
• pp.533-540
• /
• 2014

The Wangdol-cho area, in the Hupo Bank, plays a very important role in main fishing grounds, leisure tourism and marine environmental researches of the East Sea. We analyzed the detailed bathymetry and classified the seabed characteristics of the Wangdol-cho area, based on seafloor backscattering images and sediment grain size. The Hupo Bank is developed in parallel with the eastern coastal line of Korean peninsula, and the shallowest area (Wangdol-cho) of the Hupo Bank is located along the eastern part of Hupo Port. The Wangdol-cho comprises three summits; north summit, middle summit, and south summit. The middle summit area among the three summits has the most shallow water depth with minimum about 6 m. The north summit shows about 8 m minimum depth and the south summit about 9 m. The bathymetry data around three summits represent undulating seabeds with many scattered underwater reefs and shallow water depth. The area between the underwater reefs, the flat seafloor in the northeastern part of the survey site, and the western steep slope area have relatively coarse sediments such as sandy gravel and gravelly sand. The bathymetry in the western side of the Wangdol-cho shows steep slope seabed, extending to the Hupo Basin. Fine sediments including mud and silty sand occur in the Hupo Basin area of the survey site. The submarine detailed topography and the analysis of the seafloor characteristics of the survey area are expected to contribute to management for marine environmental researches and sustainable use of ecosystems in the Wangdol-cho.

• Economic and Environmental Geology
• /
• v.44 no.1
• /
• pp.49-57
• /
• 2011

Water budget analysis in the groundwater system was conducted in order to understand water budget distributions in the ground water system in Geum-gang watershed. The annual amounts of precipitation, runoff, evapotranspiration, dam storage change and water supply over the sub-watershed in Geum-gang watershed were evaluated the residual groundwater from 2002 to 2006, based on the water budget considering inflow and outflow. Then we are able to expect residual groundwater of each sub-basin. According to the result of study, the year 2003 and 2006 were recorded the highest and the lowest precipitation value, respectively. Average run-off percentage against precipitation was 60.44%. Annual evapotranspiration in each of years didn't show the remarkable variations but the values were high in the lower reaches of the basin. The residual waters in Geum-gang basin were determined to be 133.36 in 2002, 77.64 in 2003, -19.40 in 2004, -82.25 in 2005 and -128.07 mm in 2006. The residual water in Geum-gang basin was high in the main and up stream such as Maepo. Also the residual water showed low distributions in Nonsan and Seokhwa.

• Economic and Environmental Geology
• /
• v.45 no.2
• /
• pp.157-167
• /
• 2012

This study aimed to interpret the provenance and firing temperature of pottery from Chipyeongdong site in Gwangju, Korea though mineralogical and geochemical methods and also investigated the post-depositional alteration of pottery in burial environments. It is also presumed that they were made of soils near the site because they have similar mineralogical composition and same geochemical evolution path. Based on the results of mineralogical analysis, the pottery samples are largely divided into 2 groups; $700^{\circ}C$ to $1,000^{\circ}C$ and 1,000 to $1,100^{\circ}C$. At some pottery fired at over $1,000^{\circ}C$, it is thought that the refinement of raw materials were processed to remove macrocrystalline fragments. However, it was found that phosphate in soil environments formed amorphous aggregates with Al and Fe within the pores and voids on pottery fired at the low temperature. It indicates the contamination of pottery after burial.

• Economic and Environmental Geology
• /
• v.45 no.5
• /
• pp.565-578
• /
• 2012

Sedimentary facies of the Middle to Upper Cambrian Sesong Formation, Taebacksan Basin, are analyzed using detailed field mapping and stratigraphic section measuring. As a result, five sedimentary facies are recognized in the formation, which include lime nodule bearing shale facies, anastomosing wackestone-packstone facies, well-laminated siltstone facies, fine to medium sandstone facies and lime pebble conglomerate facies. Together with sedimentary facies analysis, study on vertical facies variation indicates that the Sesong Formation was deposited in an outer to inner shelf during relative sea-level fall. Especially, shallow marine aspects of the upper part of the Sesong Formation including 10-m-thick, fine to medium-grained sandstones appear to be very similar with the shallow marine strata accumulated during the Steptoean Stage (Dunderbergia) in Laurentia. These lithofacies comparisons of coeval strata between two continents suggest that sedimentation in the Sesong Formation reflects the influence of global sea-level fall occurred during the late Middle Cambrian to early Late Cambrian. As well, a stratigraphic discontinuity surface that may have sequence stratigraphic significance is recognized within the shallow marine sandstone beds of the uppermost Sesong Formation. This stratigraphic discontinuity surface may correspond to the Sauk II-III sequence boundary in Laurentia. Therefore, results delineated in this study will use a new stratigraphic paradigm for regional correlation of the Middle to Late Cambrian strata (e.g., the Sesong Formation) in the Taebacksan Basin, and will provide very useful information on intercontinental stratigraphic correlation in the future.

• Economic and Environmental Geology
• /
• v.45 no.5
• /
• pp.551-564
• /
• 2012

This study carried out palynological analysis and seismic interpretation to establish a stratigraphic and environmental reconstruction mainly based on fossil palynomorphs and seismic reflection data correlated with the oil exploation well (BP-1) located in the Sora Sub-basin. There were frequent environmental and floral changes due to sea level change in the Sora Sub-basin. The palynomorph assemblages found in the well sediments enabled paleoecological zonation of the well sediment sequence resulting in 4 zones: Ecozone III, Ecozone IV, Ecozone V, Ecozone VI. Index fossils among palynomorphs indicate geological ages of the units within the well ranging from Eocene to Pleistocene, and paleoenvironment varies from freshwater to inner neritic marine. Previous studies suggest that the marine deposits were slightly different in stratigraphic range from well to well. It is considered the difference is credited to geomorphological setting. This study also shows stratigraphic correlation between existing wells and BP-1 well to establishes a standard stratigraphy of the Domi Basin.

• Economic and Environmental Geology
• /
• v.45 no.2
• /
• pp.79-88
• /
• 2012

The increased brightness and focused X-ray beams now available from laboratory X-ray sources facilitates a variety of powder diffraction experiments not practical using conventional in-house sources. Furthermore, the increased availability of 2-dimensional area detectors, along with implementation of improved software and customized sample environmental cells, makes possible new classes of in-situ and time-resolved diffraction experiments. These include phase transitions under variable pressure- and temperature conditions and ion-exchange reactions. Examples of in-situ and time-resolved studies which are presented here include: (1) time-resolved data to evaluate the kinetics and mechanism of ion exchange in mineral natrolite; (2) in-situ dehydration and thermal expansion behaviors of ion-exchanged natrolite; and (3) observations of the phases forming under controlled hydrostatic pressure conditions in ion-exchanged natrolite. Both the quantity and quality of the in-situ diffraction data are such to allow evaluation of the reaction pathway and Rietveld analysis on selected dataset. These laboratory-based in-situ studies will increase the predictability of the follow-up experiments at more specialized beamlines at the synchrotron.

• Economic and Environmental Geology
• /
• v.46 no.5
• /
• pp.411-424
• /
• 2013

Assessment and damage reduction strategy of acidic rock drainage were conducted in a section of ${\bigcirc}{\bigcirc}$ highway construction site. The geology of the studied section consists of Icheonri sandstone and intermediate to acidic volcanic rocks. Sulfides occur as a disseminated type in sandstone and volcanics which were altered by the hydrothermal solution of granite intrusion. Volcanics and sandstone with a high content of sulfide were classified as a potentially acid rock drainage(ARD) forming rock. The drainage originated from those rocks may acidify and contaminate the surrounding area during the highway construction. Therefore, the drainage should be treated before it is discharged. A slope landslide hazard due to the ARD was also expected and the coating technology was recommended for the reduction of ARD generation as a preemptive measure before reinforcement work for enhancing slope stability such as shotcrete and anchor. According to the ARD risk analysis, those rocks should not be used as cement aggregate, but only to be used as a bank fill material of a filling-up system that allows minimal contact with rainfall and groundwater.