• Economic and Environmental Geology
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• v.47 no.4
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• pp.363-379
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• 2014

The Haenam Pb-Zn skarn deposit is located at the Hwawon peninsula in the southwestern part of the Ogcheon Metamorphic Belt. The deposit is developed along the contact between limestone of the Ogcheon group and Cretaceous quartz porphyry. Petrography of ore samples, chemical composition of skarn and ore minerals, and geochemistry of the related igneous rocks were investigated to understand the characteristics of the skarn mineralization. Skarn zonation consists of garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone, pyroxene+garnet+quartz${\pm}$calcite zone, calcite+pyroxene${\pm}$garnet zone, quartz+calcite${\pm}$pyroxene zone, and calcite${\pm}$chlorite zone in succession toward carbonate rock. Garnet commonly shows zonal texture comprised of andradite and grossular. Pyroxene varies from Mn-hedenbergite to diopside as away from the intrusive rock. Chalcopyrite occurs as major ore mineral near the intrusive rock, and sphalerite and galena tend to increase as going away. Electron probe microanalyses revealed that FeS contents of sphalerite become decreased from 5.17 mole % for garnet${\pm}$pyroxene${\pm}$calcite${\pm}$quartz zone to 2.93 mole %, and to 0.40 mole % for calcite+pyroxene${\pm}$garnet zone, gradually. Ag and Bi contents also decreased from 0.72 wt.% and 1.62 wt.% to <0.01 wt.% and 0.11 wt.%, respectively. Thus, the Haenam deposit shows systematic variation of species and chemical compositions of ore minerals with skarn zoned texture. The related intrusive rock, quartz porphyry, expresses more differentiated characteristics than Zn-skarn deposit of Meinert(1995), and has relatively high$SiO_2$ concentration of 72.76~75.38 wt.% and shows geochemical features classified as calc-alkaline, peraluminous igneous rock and volcanic arc tectonic setting.

• The Journal of the Petrological Society of Korea
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• v.7 no.2
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• pp.111-131
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• 1998

The migmatitic gneiss in the Odesan Gneiss Complex has small amount of quartzite, amphibolite and marble and the Kuryong Group which contact with migmatitic gneiss unconformitly, also contains some amphibolite. Preview studies of this area had regarded that the amphibolites contact with marble had been produced by metasomatism from the pelitic and calcareous sediments mixtures, but the amphibolite is reinterpreted as igneous origin. $SiO_2$ content of the amphibolite is 45.9~52.7 wt%, which corresponds to basaltic composition. MgO content has narrow range (4.6~6.87 wt%) and major and trace element are plotted against MgO,$TiO_2, P_2O_5$, Hf, Zr are reduced and Cr and Ni are increased their content with increasing MgO. This phenomenon indicates that the basaltic magma as the protolith of the amphibolite had frationated with the crystallization of the pyroxene and/or olivine. REE pattern has smoothly decrease from LREE to HREE. Eu/Eu(0.83~1.19) show the flat Eu anomaly, which indicate small fractional crystallization of plagioclase. HREE is enriched in the garnet-bearing amphibolites. Several discrimination diagram for the basaltic magma show that the amphibolite of the study area is originated tholeiitic basaltic magma indicating continental rift environment. Due to determine the metamorphic condition garnet-hornblende geothermometry and hornblende-plagioclase geobarometry are used. Peak metamorphic temperature range of the amphibolite $788~870^{\circ}C$ and is deduced toward the northeastern part. The calculated temperature from the amphibolite has slightly higher than the temperature of the metapelites but the trend of metamorphic grade which decrease from western to eastern part progradly is similar to each other. The metamorphic pressure calculated by garnet- hornblede-plagioclase geobarometry is 4~5kb. But ilmenite-plagioclase pair enclosed in garnet show 8 kb at $700^{\circ}C$ by garnet-ilmenite-rutile-plagioclase geobarometery. The zonal profile of garnet in sample 84 shows the bell-shape profile, which grossular content decreases whereas pyrope content increases progressively. This means that the amphibolite has undergone the clockwise P-T-t path which is shown in the migmatitic gneiss of the Odesan Gneiss Complex.

• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.1-15
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• 2020

This study was conducted to determine whether invasive muskrats settle in the natural ecosystem of Korea. The study also aimed to provide information on the selection of target areas, basic behavioral characteristics, and habitat use-related data, all of which are essential for effective management strategy establishment and site management. To this end, a trend in international muskrat management was identified to examine the management direction according to the settlement stage. We also secured the location of 72 domestic farmers and classified five regions in Gyeonggi-do, Chungcheongnam-do, Gyeongsangbuk-do, and Sejong Special Self-governing City into regions with high potential for natural leakage to raise the need for a quick survey. We determined that muskrats successfully settled in the natural ecosystem of Korea, based on the fact that we consistently identified a muskrat habitat at the same point for three years, from 2016 to 2018, the age of the captured population was estimated to be 1.2 years, and there had been no additional make-up factors near the habitat since 2012. The muskrats that settled in Korea showed a small home range of 0.0027 ㎢ (MCP 95%) and were estimated to show regular mobility before Spring and Autumn. Also, the areas where the muskrat habitat was observed had a high level of habitat environment disturbance and their ecological and food intake characteristics reflected that disturbance. Muskrat traces were high in hydrophyte vegetation, which can be used as a hideout in open waters and where the growth of both floating leaved plants and floating plants are prevalent. Since international invasive muskrats have already settled in the domestic ecosystem and there is concern about their proliferation in the future, the government must consider a preemptive response and scientific management.

• Economic and Environmental Geology
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• v.35 no.3
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• pp.203-210
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• 2002

In order to elucidate the growth mechanism of sulfide chimney formed as a result of seafloor hydrothermal mineralization, we carried out the mineralogical and fluid inclusion studies on the inactive, sulfide- and silica-rich chimney which has been recovered from a hydrothermal field in the Cleft segment of the Juan de Fuca Ridge. According to previous studies, many active and inactive vents are present in the Cleft segment. The sulfide- and silica-rich chimney is composed of amorphous silica, pyrite, sphalerite and wurtzite with minor amounts of chalcopyrite and marcasite. The interior part of the chimney is highly porous and represents a flow channel. Open spaces within chimneys are typically coated with colloform layers of amorphous silica. The FeS content of Zn-sulfides varies widely from 13.9 to 34.3 mole% with Fe-rich core and Fe-poor rims. This variation possibly reflects the change of physicochemical characteristics of hydrothermal fluids. Chemical and mineralogical compositions of the each growth zone are also varied, possibly due to a thermal gradient. Based on the microthermometric measurements of liquid-rich, two-phase inclusions in amorphous silica that was precipitated in the late stage of mineralization, minimum trapping temperatures are estimated to be about 1140 to 145$^{\circ}$C with the salinities between 3.2 and 4.8 wt.% NaCI equiv. Although the actual fluid temperatures of the vent are not available, this study suggests that the lowtemperature conditions were predominant during the mineralization in the hydrothermal field at Cleft segment. Comparing with the previously reported chimney types, the morphology, colloform texture, bulk chemistry, and a characteristic mineral assemblage (pyrite + marcasite + wurtzite + amorphous silica) of this chimney indicate that the chimney have been formed from a relatively low-temperature (<250$^{\circ}$C) hydrothermal fluid that was changed by sluggish fluid flow and conductive cooling.

• The Journal of Engineering Geology
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• v.23 no.2
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• pp.171-186
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• 2013

A drilling project was undertaken to characterize the geochemical relationship and the occurrence of radioactive materials at a test site among public-use groundwaters previously known to have high occurrence of uranium and radon-222 in the Daejeon area. A borehole (121 m deep) was drilled and core rocks mainly consist of two-mica granite, and associated with pegmatite and dykes of intermediate composition. The groundwater samples collected at six different depths in the borehole by a double-packed system showed the pH values ranging from neutral to alkaline (7.10-9.3), and electrical conductivity ranging from 263 to 443 ${\mu}S/cm$. The chemical composition of the borehole groundwaters was of the $Ca-HCO_3(SO_4+Cl)$ type. The uranium and Rn-222 contents in the groundwater were 109-1,020 ppb and 9,190-32,800 pCi/L, respectively. These levels exceed the regulation guidelines of US EPA. The zone of the highest groundwater uranium content occurred at depths of 45 to 55m. The groundwater chemistry in this zone (alkaline, oxidated, and high in bicarbonate) is favorable for the dissolution of uranium into groundwater. The dominant uranium complex in groundwater is likely to be $(UO_2CO_3)^0$ or $(UO_2HCO_3)^+$. Radon-222 content in groundwater shows an increasing trend with depth. The uranium and thorium contents in the core were 0.372-47.42 ppm and 0.388-11.22 ppm, respectively. These levels are higher values than those previously been reported in Korea. Microscopic observations and electron microprobe analysis(EPMA) revealed that the minerals containing U and Th are monazite, apatite, epidote, and feldspar. U and Th in these minerals are likely to substitute for major elements in crystal lattice.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.962-969
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• 2016

This study assessed the ecological and behavioral characteristics of the sika deer from April 2012 to August 2016. To obtain basic information on the behavioral patterns of the sika deer (Cervus nippon) including their annual home range, sika deer wearing GPS tracking collars were released into 1,385 locations at a different altitude around where they had been captured in Songnisan. The released individuals were studied through home range analysis. According to our observations, annual home ranges of the sika deer (n=6) is seen to be $2.24{\pm}1.50km^2$ (t=3.648, p<0.05) of MCP 95% for the entire area of home range and $0.46{\pm}0.31km^2$ (t=3.666, p<0.05)$km^2$ of FK 50% for the home range core area respectively. The annual home ranges of the sika deers by sex were $2.94km^2$ for female and $1.53km^2$ for male. This study is expected to provide basic data for habitat management and ecological study of sika deer and to contribute to the management of wild animals.

• Korean Journal of Environment and Ecology
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• v.32 no.5
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• pp.478-485
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• 2018

With the total population of 3,356 worldwide as of 2016, the black-faced spoonbill (Platalea minor) is designated as "endangered (EN)" species by IUCN. About 70% of population breeds on the uninhabited islands near the west coast of Korea and wintering area is Taiwan, China, Hong Kong, etc. However, there is few detail research in Korea and East Asia on black-faced spoonbill's long range migration and its habitat when migrating southward. We studied black-faced spoonbill's migration route, distribution, stopover, wintering sites, and timing of migration movements using a wild-tracker (WT-200, GPS-Mobile phone based telemetry, KoEco). We caught the black-faced spoonbills in the breeding sites (Gugi island, Bi island, Sangyeobawi, Chilsan island) in Korea in late June 2014. We attached the wild-tracker to 10 juvenile black-faced spoonbills. The tracking showed that the black-faced spoonbills started southward migration between late October and early November. The traveling distance to wintering site was maximum at 1,820 km, minimum at 746 km, the average at 1,201km. The maximum daily traveling distance was 1,479 km with an average of 782 km. The average days it took from breeding site to wintering site was 10 days (SD=10.7). The shortest duration was 2 days, and the longest duration was 34 days. Most individuals used 2-3 stopover sites between the breeding sites to the wintering sites and stayed almost 1-2 days (maximum 31 days). Stopover sites were wetlands such as rivers, streams, reservoir, and mud flat. The wintering sites were coastal areas (five individuals) in China, inland (one individual) in China, Taiwan (three individuals), and Japan (one individual). In conclusion, it is necessary to preserve the stopover sites and wintering site of the black-faced spoonbills through consultation and protection policy between countries and establish the systematic preservation measures and activity plans through continued moniting and additional studies.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.675-687
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• 2005

The rocks of the five storied stone pagoda in the Jeongrimsaji temple site are 149 materials in total with porphyritic biotite granodiorite. They include pegmatite veinlet, basic xenolith and evenly developed plagioclase porphyry. This stone pagoda has comparably small fracture and cracks which are farmed in the times of rock properties, but surface exfoliation and granular decomposition are in process actively since the rocks are generally weakened from the influence of air contaminants and acid rain. Structural instability of constituting rocks in the 4th roof materials are observed to occur from distortion and tilt. Such instability is judged to threat stability of the upper part of the stone pagoda. Also, chemical weathering is operating even more as the contaminants, ferro-manganese hydroxides eluted from water-rock interaction on the rock surface. Most of the rock surface is covered with yellowish brown, dark black and light gray contaminants, and especially occur in the lower part of the roof rocks on each floor. The roof underpinning rocks are severe in surface pigmentation from manganese hydroxides and light gray contaminants. The surface of rocks lives bacteria. algae, lichen, or moss and diverse productions in colors of light gray, dark Bray and dark green. Grayish white crustose lichen grows thick on the surface with darkly discolored by fungi and algae in the first stage on basement rocks, and weeds grows wild on the upper part of each roof rocks. This stone pagoda must closely observe the movements of the upper part rock materials through minute safety diagnosis and long term monitoring for structural stability. Especially since the surface discoloration of rocks and pigmentation of secondary contaminants are severe, establishment of general restoration and scientific conservation treatment are necessary through more detailed study for this stone pagoda.

• Economic and Environmental Geology
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• v.44 no.2
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• pp.123-133
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• 2011

The lab scale experiments to investigate the geochemical reaction among supercritical $CO_2$-mineral-brine which occurs at $CO_2$ sequestration sites were performed. High pressurized cell system (l00 bar and $50^{\circ}C$) was designed to create supercritical $CO_2$ in the cell, simulating the sub-surface $CO_2$ storage site. From the high pressurized cell experiment, the surface changes of Ca-feldspar, amphibole (tremolite) and olivine, resulted from the supercritical $CO_2$-mineral-brine reaction, were observed and the dissolution of minerals into the brine was also investigated. The mineral slabs were polished and three locations on the surface were randomly selected for the image analysis of SPM and the surface roughness value (SRV) of those locations were calculated to quantify the change of mineral surface for 30 days. At a certain time interval, SPM images and SRVs of the same mineral surface were acquired. The secondary minerals precipitated on the mineral surfaces were also analyzed on SEM/EDS after the experiment. From the experiments, the average SRV of Ca-feldspar increased from 2.77 nm to 20.87 nm for 30 days, suggesting that the dissolution of Ca-feldspar occurs in active when the feldspars contact with supercritical $CO_2$ and brine. For the amphibole, the average SRV increased from 2.54 nm to 8.31 nm and for the olivine from 0.77 nm to 11.03 run. For the Ca-feldspar, $Ca^{2+}$, $Na^+$, $Fe^{2+}$, $Si^{4+}$, $K^+$ and $Mg^{2+}$ were dissolved in the highest order and $Si^{4+}$, $Ca^{2+}$, $Fe^{2+}$ and $Mg^{2+}$ for the amphibole. Fe (or Mg) - oxides were precipitated as the secondary minerals on the surfaces of amphibole and olivine after 30 days reaction. Results suggested that $Ca^{2+}$, $Fe^{2+}$ and $Mg^{2+}$ rich minerals would be significantly weathered when it contacts with the supercritical $CO_2$ and brine at $CO_2$ sequestration sites.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.103-120
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• 2002

In the Baekdong-Hongseong area, the southwestern part of the Gyeonggi Massif in Korea, ultramafic rocks occur as lenses within Precambrian granitic gneiss. At Baekdong area, ultramafic lens contains metabasite boudin which had undergone at least three stages of metamorphisms. The mineral assemblage on the first stage, Garnet+Sodic Augite+Hornblende+Plagioclase+Titanite, is recognized from the inclusions in garnet. The second stage is represented by the assemblage in matrix, Garnet+ Augite+Hornblende+Plagioclase, while the third stage is identified by the Hornblende+Plagjoclase $\pm$ Garnet assemblage in the symplectite formed around garnet. The P-T conditions of the first and the third stages are $690-780^{\circ}C$, 11.8-15.9 kb and $490-610^{\circ}C$, 4.0-6.3 kb, respectively. These data indicate that metabasite in Baekdong area had experienced a retrouade P-T path from the eclogite(EG) - high-pressure granulite (HG)-amphibolite (AM) transitional facies to the AM through HG-AM transitional facies. The core and rim of garnet in country granitic gneiss give $605-815^{\circ}C$, 10.7-16.0 kb and $575-680^{\circ}C$, 5.4-7.0 kb, respectively, indicating that the retrograde P-T path of granitic gneiss is similar to that of metabasite. Trace element data reveals that the tectonic setting of metabasite is island uc. The general geology, the metamorphic evolution, the mineral chemistry and the tectonic setting of Baekdong area indicate that the Baekdong-Hongseong area in Korea is a possible extension of the Sulu collision Belt in China. On the other hand, the Sm-Nd whole rock-garnet isochron ages of metabasites are 268.7-297.9 Ma which are older than the ages of UHP metamorphism (208-245 Ma) in the Dabie-Sulu Collision Belt. The older metamorphic ages suggest that collision between Sino-Korea and Yangtz plates may have occurred earlier in Korean Peninsula than China.