• Economic and Environmental Geology
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• v.41 no.1
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• pp.15-32
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• 2008

The hydrochemical and isotopic (stable isotopes and noble gas isotopes) analyses for hot spring waters, cold groundwaters and surface water samples from the Seokmodo hot spring area of the Ganghwa province were carried out to characterize the hydrogeochemical characteristics of thermal waters and to interpret the source of thermal water and noble gases and the geochemical evolution of hot spring waters in the Seokmodo geothermal system. The hot spring waters and groundwaters show a weakly acidic condition with the pH values ranging from 6.42 to 6.77 and 6.01 to 7.71 respectively. The outflow temperature of the Seokmodo hot spring waters ranges from $43.3^{\circ}C\;to\;68.6^{\circ}C$. Relatively high values of the electrical conductivities which fall between 60,200 and $84,300{\mu}S/cm$ indicate that the hot spring waters were mixed with seawater in the subsurface geothermal system. The chemical compositions of the Seokmodo hot spring waters are characterized by Na-Ca-Cl water type. On the other hand, cold groundwaters and surface waters can be grouped into three types such as the Na(Ca)-$HCO_3$, Na(Ca)-$SO_4$ and Ca-$HCO_3$ types. The ${\delta}^{18}O\;and\;{\delta}D$ values of hot spring waters vary from -4.41 to -4.47%o and -32.0 to -33.5%o, respectively. Cold groundwaters range from -7.07 to -8.55%o in ${\delta}^{18}O$ and from -50.24 to -59.6%o in ${\delta}D$. The oxygen and hydrogen isotopic data indicate that the hot spring waters were originated from the local meteoric water source. The enrichments of heavy isotopes ($^{18}O\;and\;^2H$) in the Seokmodo hot spring waters imply that the thermal water was derived from the diffusion Bone between fresh and salt waters. The ${\delta}^{34}S$ values ranging from 23.1 to 23.5%o of dissolved sulfate are very close to the value of sea water sulfate of ${\delta}^{34}$S=20.2%o in this area, indicating the origin of sulfate in hot springs from sea water. The $^3H/^4He$ ratio of hot spring waters varies from $1.243{\times}10^{-6}\;to\;1.299{\times}10^{-6}cm^3STP/g$, which suggests that He gas in hot spring waters was partly originated from a mantle source. Argon isotopic ratio $(^{40}Ar/^{36}Ar=298{\times}10^{-6}cm^3STP/g)$ in hot spring waters corresponds to the atmospheric value.

• Economic and Environmental Geology
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• v.43 no.2
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• pp.163-176
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• 2010

We report twenty data for early lavas erupted during the initial period of formation of Jeju Island on the basis of review on 539 data of whole-rock greochemistry and $^{40}Ar/^{39}Ar$ age dating out of mainly core samples from 69 boreholes drilled in the lower land since 2001 and 66 outcrop sites. Out of 69 boreholes, the early lava flow units are identified from samples collected from Beophocheon (EL 235 m, 210 m deep), Donnaeko (EL 240 m, 230 deep), Donghong-S (EL 187 m, 340 m deep), 05Donghong (EL. 187.6 m, 340 m deep), Dosoon (EL 305 m, 287 m deep), Sangye (EL 230 m, 260 m deep), Mureung-1 (EL 10.2 m, 160 m deep), and Gapa (EL 17.5 m, 92 m deep), which are located in the southern and southwestern portion of Jeju Island. While, the well-known outcrops from Sanbangsan, Wolrabong, Wonmansa, and Kagsubawi are also reconfirmed. $^{40}Ar/^{39}Ar$ age dating results of these lavas range from 1 Ma to 0.7 Ma, indicating that the data can be useful to constrain on age and geochemical characteristics of early lava effusion period in the formation of Jeju Island. Especially, samples with trachybasalt in composition collected from 143 m to 137 m, and from 135 m to 123 m below ground surface at 05Donghong hole have the oldest ages, $992\pm21$ Ka and $988\pm38$ Ka, respectively. This study suggests that in Jeju Island the first lava with trachybasalt in composition may have effused around 1 Ma ago, and the effusion style and chemical compositions of lavas must have changed to the formation of lava domes with trachyte-trachyandesite-basaltic trachyandesite and the eruption of lavas with alkali basalt and trachybasalt intermittently during the period from 0.9 Ma to 0.7 Ma ago. It also indicates that the initial lava flows below the ground are intercalated with or underlain by the Seoguipo Formation except for several exposed domal structure areas such as Sanbangsan and Kagsubawi, implying that the early lava effusion may have intermittently and sporadically occurred with nearby hydrovolcanism and sedimentation.

• Applied Biological Chemistry
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• v.32 no.1
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• pp.14-22
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• 1989

Chemical composition of the oyster mushroom(Pleurotus spp.) at different cropping stage were analyzed. The contents of crude protein, soluble protein, reducing sugar, total sugar and crude fat in Pleurotus ostreatus 201 were a little higher than those of Pleurotus sajorcaju. The Component contents were not different from the first to the second flush, while the contents were slightly decreased from the third flush. A11 component contents were highest in $3{\sim}5cm$ pileus size, the contents were slightly decreased as pileus size increase to over $3{\sim}5cm$, except for reducing sugar. Crude fiber content in Pleurotus sajor-caju were a little more than Pleurotus ostreatus 201, and in course of increasing cropping time, ash contens of two strains were simmilar, and were decreased after the second flush. These component contents mere increased by the growth of the pileus. The sugars were identified as xylose, glucose, mannitol and trehalose in Pleurotus sajor-caju, and xylose, fructose, glucose, mannitol and trehalose in Pleurotus ostreatus 201, respectively. Mannitol and trehalose contents in Pleurotus sajor-caju were a little more than that in Pleurotus ostreatus 201. Glucose content of Pleurotus sajor-caju and Pleurotus ostreatus 201 was highest in $1{\sim}3cm$ pileus size, while other sugars in $3{\sim}5cm$ pileus size, and the sugar contents were decreased at over the above size of the pileus.

• The Journal of the Petrological Society of Korea
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• v.4 no.1
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• pp.61-87
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• 1995

On the basis of lithology, the Precambrian Hongjesa Granitic Gneiss can be locally zoned into granoblastic granitic gneiss, porphyroblastic granitic gneiss, migmatitic gneiss from its center to the marginal part. There are no distinct differences in mineral assemblages by lithologic zoning, but it partly shows the change of mineral assemblage in the adjacent with migmatitic gneiss, thus mineral assemblage can be subdivided into Zone I and Zone II. In terms of mineral compositions, the characteristics of Zone I are coexisting K-feldspar+muscovite+sillimanite. The characteristics of Zone II are (1) breakdown of muscovite, (2) coexisting garnetScordierite, (3) coexisting garnet+cordierite + orthoamphibole. The Buncheon Granitic Gneiss is mainly composed of augen gneiss. In the adjacent area with Honjesa Granitic Gneisses, Buncheon Granitic Gneiss has the mineral assemblage of sillimanite+biotite+K-feldspar+(kyanite). Kyanite occurs as relict grains in the Buncheon and Hongjesa Granitic Gneissess. Kyanite shows anhedral to subhedral form and coexists with sillimanite in only one of these samples. Garnet from a migmatitic gneiss (Zone 11) has relatively high $X_{Fe}$ value in core and rim. Garnet from a porphyroblastic granitic gneiss(Zone I) has relatively homogemeous core but compositionally-zoned rim. Biotites show various colour from greenish-brown, brown to reddish brown at maximum adsorption. Also, the Ti, and Mg content in biotites increases from Zone I to Zone II. The plagioclases shows the chemical composition of $Ab_{84}An_{16}$ -$Ab_{70}An_{30}$ (oligoclase) in Zone I and $Ab_{70}An_{30}$ -$Ab_{50}An_{50}$(andesine) in Zone 11. These variations indicate that the gneisses in the study area experienced a upperamphibolite facies. The presence of kyanite as relict grains indicates that the metamorphic rocks in this area exprienced a high-temperature/medium-pressure type metamorphism, followed by high-temperaturellow-pressure metamorphism. Metamorphic P-T conditions for each gneiss estimated from various geothermobarometers and phase equilibria are 698-$729^{\circ}C$/6.3-11.3 kbar in augen gneiss, 621-$667^{\circ}C$/1.0-5.4 kbar in migmatitic gneiss, and 602-$624^{\circ}C$/1.9-3.4 kbar in porphyroblastic granitic gneiss. These data suggest that the study area was subjected to a clockwise P-T path with isothermal decompression (dP/dT=about 60 bar/$^{\circ}C$).

• Journal of the Mineralogical Society of Korea
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• v.24 no.3
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• pp.235-244
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• 2011

A batch experiment of pyrite oxidation was performed and the surfaces of the reacted pyrite were regularly observed with the scanning electron microscope (SEM) together with the chemical compositions of the solution to help understand the oxidation mechanisms of pyrite by Acidithiobacillus ferrooxidans (Af). The dissolved Fe concentrations clearly indicated that Af experiences the lag and then exponential growth phase. An Af cell was observed to be attached to the surface of pyrite during the lag, implying that a direct leaching by the microbe really happens for the period. It is not certain, however, whether the main mechanism of pyrite oxidation during that time was the direct leaching or not, because there were just a few cells confirmed to be attached and most of the dissolved Fe was Fe(III). The dissolved Fe concentration stayed almost constant from the mid-lag phase to just before the onset of the exponential phase, suggesting that AI needs an adaptation time to switch its oxidation mechanism from one to the other whichever it is during that stage of growth. The moment of Af's cell division was observed by SEM on the surface of pyrite during the lag phase. The corrosion outline around the dividing cell was quite similar to the shape of the cell itself, which implies that the rate of the microbial oxidation is very uneven and the rate when the cell metabolizes should be much faster than that calculated from the concentration variation of the dissolved Fe. The number of etch holes by Af is much higher on the inoculated surfaces, indicating the average rate of pyrite oxidation is also much faster than that of abiotic oxidation. The microbial etch holes on pyrite surface are small and deep, which may influence the transition of the growth phases of Af from lag to exponential.

• Economic and Environmental Geology
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• v.42 no.4
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• pp.289-300
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• 2009

The Geodo mine area, had been developed for Fe and Cu ores since 1963 and abandoned in recent decades, is located in the central part of the Taebaeksan mineralized district. This area comprises of the Jangsan, Myobong, Pungchon, Hwajeol, Dongjeom, and Dumugol Formations in ascending stratigraphic order. These Formations were intruded by the Cretaceous Eopyeong granitoids that appears to produce the Geodo skarn. Their compositions are relatively oxidized quartz monzodiorite to granodiorite (magnetite series, $Fe_2O_3/FeO=0.3{\sim}1.1$). Mineralizations related skarn deposit occur in the Myobong, Pungchon, and Hwajeol Formations. The proximal skarn is zoned from andraditic garnet ($Ad_{44-95}Gr_{1-53}$) predominant adjacent to the Eopyeong granitoids to diopsidic pyroxene ($Hd_{10-100}Di_{0-89}$) predominant away from the one. The differential proportion of garnet and pyroxene is generated by water/rock ratio and their source, such as magmatic and meteoric water. This is useful tool for assessment the overall oxidation state of the entire skarn system. Gold occurs in proximal red to brownish garnet skarn, and genetically associated with Bi- and Te-bearing minerals. Skarn deposit developed in the Geodo mine area is considered as oxidized Au skarn category, based on chemical composition of the Eopyeong granitoids, zonation of skarn, and gold occurrences. Garnet-rich skarn zone will be the main target for exploration of gold in the study area. However, it is needed to the detailed survey on vertical zonation of this area as well as lateral zonation. The result of this survey would provide an important basis for the exploration of the skarn Au deposit in the Geodo mine area.

• Journal of The Korean Society of Grassland and Forage Science
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• v.9 no.1
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• pp.34-42
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• 1989

This pot experiments were conducted to find out the optimal fertilization ratios of ${\Sigma}anion$ : ${\Sigma}cation$, ${\Sigma}A$/${\Sigma}C$, and the optimal application rates of total major nutrients in an orchardgrass/ladino clover mixed sward. The optimum ratios and concentrations in equivalent basis were computed by the Homes systematic variations technique. The results were summarized as follows; 1. The optimum fertilization ratios of ${\Sigma}A$ : ${\Sigma}C$ and the optimum application rates of total nutrients for the high yields by forage species in a mixed sward were obtained (Table 6 in detail); ${\Sigma}A$ : ${\Sigma}C$ = 2 : 1 at 80 and 320 meq/pot, and 3 : 2 at 560 and 800 meq for grass and grass plus legume, and ${\Sigma}A$ : ${\Sigma}C$ = 1 : 2 for legume in general. 2. The optimum application rates of total nutrients for the high yields of grass and grass plus kgum were increased by decreasing the ${\Sigma}A$/ ${\Sigma}C$: ratio, whereas these for legume showed a valible. range without significance. 3. The yields 01 grass and grass plus legume were generally increasing by increasing both the ${\Sigma}A$/ ${\Sigma}C$ ratio and total concentration, but they were significantly higher at the ${\Sigma}A$/ ${\Sigma}C$ = 1.273 than at the 2.125 under the high total ion concentration. The legume yields were proportional to ${\Sigma}C$ ratio and increased by increasing the total ion concentration under the condition of high ${\Sigma}C$ ratio. 4. The efficiencies of ${\Sigma}A$ and ${\Sigma}C$ in relation to the grass and grass plus legume yields were highest with the low ratios of each other and the low rates of total nutrients ${\Sigma}A$ efficiency m the legume yield tended to be similar to that of ${\Sigma}A$ in the grass yield noted above. The ${\Sigma}C$ efficiency in the legume yield, however, was generally proportional to the ${\Sigma}C$ ratio except at the low rate of 80 meqlpot. 5. The yields of grass plus legume, yield components and botanical compositions in a mixed sward were greatly influenced by the ${\Sigma}A$/${\Sigma}C$ ratios, the fertilization rates of total nutrients, and the interaction of ratio and rate noted above. These effects were generally different and opposite accading to grass and legume. In addition, the soil chemical properties and mineral contents of forages were partially influenced by these systematic variations.

• Journal of Korean society of Dental Hygiene
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• v.2 no.2
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• pp.175-186
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• 2002

Fluoride has been one of the most widely studied caries-preventive agents. But the effect of prenatal administration had been controversies for many years. The results showed that there were no influence on reproductive rate of rats with administration of fluoride from 0 to 20 ppm during pregnancy(p>0.05). There was a trend towards slightly increased the mean ash weight in the 1, 5 and 20 ppm groups, as compared with the control group. However, there was no significant differences among groups (p>0.05). The contents of calcium, magnesium and phosphorus in the total bone were increased with the administrated fluoride concentration were increased, but there were no statistically significant differences among groups(p>0.05). The mean fluoride level of 1 ppm group was significantly higher than that of control group, but the concentrations of fluoride in total carcass pups of 5 and 20 ppm groups were significantly less than that of 1 ppm group(p>0.05). The results of this study indicate that the amount of fluoride transferred to the offspring, which may produce anticariogenic effects in the primary teeth of their effects in the primary teeth of their offspring.

• Korean Journal of Ecology and Environment
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• v.44 no.2
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• pp.239-251
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• 2011

To compare the different water environments in the Jigsaw stream (st. 1, 2) and Jujin stream (st. 3, 4) crossing over the Byeonsan-Bando and Seonunsan parklands, the physico-chemical factors and the species compositions of epilithic diatoms were analyzed from March 2009 to February 2010. The mean values of conductivity (681.1 ${\mu}S\;cm^{-1}$), suspended solids (27.83 mg $L^{-1}$), biological oxygen demand (3.15 mg $L^{-1}$), total nitrogen (3.24 mg $L^{-1}$), total phosphorus (0.24 mg $L^{-1}$) and chlorophyll-${\alpha}$ (12.99 mg $m^{-3}$ ) in Jujin stream were significantly higher than each element in Jigsaw stream. Eighty taxa were classified into 73 species and seven varieties belonging to 24 genera, eight families, three suborders and two orders in Jigsaw stream. Eighty eight taxa were classified into 81 species and seven varieties belonging to 22 genera, seven families, three suborders and two orders in Jujin stream. Biological water quality assessments revealed that Jigsaw stream was ${\beta}$~${\alpha}$-oligosaprobic and Jujin stream was ${\beta}$-mesosaprobic. Dominant and diversity indices were indicated from 0.25~0.81 and from 1.73~4.14 in Jigsaw stream, respectively, and from 0.29~0.64 and from 2.72~4.02 in Jujin stream, respectively. Jujin stream was more eutrophic than those of Jigsaw stream. The different water environments between the two streams could be due to the different ecosystems of the neighboring basins of each stream crossing over in the mountain. Further studies should investigate the water environments of two streams by continuous and regular monitoring to analyze the different ecosystem mechanisms.

• The Journal of the Petrological Society of Korea
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• v.10 no.1
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• pp.27-35
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• 2001

The charnockite of Jirisan area occurs within the Precambrian high grade metamorphic terrane associated with anorthosite body as many foreign examples. Sm-Nd ages were determined from whole rock-garnet pairs, which turned out $1827\pm$32($2\sigma$) Ma for the massive charnockite and $1820\pm$22(2$\sigma$) Ma for the foliated charnockite with $$\varepsilon$_{Nd}(T)$ of $-5.5\pm$0.2 and $-6.0\pm$0.5 respectively. $^{87}Sr/^{86}Sr$ initial ratios calculated with the these ages are 0.71319 and 0.71532 respectively. The fact that massive and foliated charnockites show identical age, identical Nd isotopic initial ratio, and similar Sr isotopic initial ratios suggest that they were generated at the same time from the same material even through their present textures are different. Initial ratios of Nd and Sr of the charnockites are quite distinct from the mantle values indicating the influence of continental crust. Sm-Nd age determined from the titanium bearing anorthositic rocks intruding the anorthosite body, using mineral separates of garnet, plagioclase, and mafic fraction, is $1792\pm$90(2$\sigma$) Ma with $$\varepsilon$_{Nd}(T)=-3.9$\pm$0.2$. The ^${87}Sr/^{86}Sr$ initial ratios calculated with this age are 0.70616~0.70619. The charnockites and the anorthositic rocks occurring in contact each other also reveal the same age within the error, which suggest a genetic relationship between them. However, chemical compositions of the charnockites and Hadong-Sancheong anorthosites cannot be explained by igneous differentiation. Their differences in Nd and Sr initial isotopic ratios indicate different source materials. Therefore, temporal association between them suggests the possibility of the anorthosite acting as a thermal source for the generation of the charnockite as other studies.