• Journal of Soil and Groundwater Environment
• /
• v.13 no.1
• /
• pp.1-12
• /
• 2008

The purpose of this study is to characterize the hydrogeochemical characteristics of hot spring waters and to interpret the source of noble gases and the geochemical environment of the hot spring waters distributed along the eastern area of the Korean peninsula. For this purpose, We carried out the chemical, stable isotopic and noble gas isotopic analyses for eleven hot spring water and fourteen hot spring gas samples collected from six hot spring sites. The hot spring waters except the Osaek hot spring water show the pH range of 7.0 to 9.1. However, the Osaek $CO_2$-rich hot spring water shows a weak acid of pH 5.7. The temperature of hot spring waters in the study area ranges from $25.7^{\circ}C$ to $68.3^{\circ}C$. Electrical conductivity of hot spring waters varies widely from 202 to $7,130{\mu}S/cm$. High electrical conductivity (av., $3,890{\mu}S/sm$) by high Na and Cl contents of the Haeundae and the Dongrae hot spring waters indicates that the hot spring waters were mixed with seawater in the subsurface thermal system. The type of hot springs in the viewpoint of dissolved components can be grouped into three types: (1) alkaline Na-$HCO_3$ type including sulfur gas of the Osaek, Baekam, Dukgu and Chuksan hot springs, and (2) saline Na-Cl type of the Haeundae and Dongrae hot springs, and (3) weak acid $CO_2$-rich Na-$HCO_3$ type of Osaek hot spring. Tritium ratios of the Haeundae and the Dongrae hot springs indicate different residence time in their aquifers of older water of $0.0{\sim}0.3$ TU and younger water of $5.9{\sim}8.8$ TU. The ${\delta}^{18}O$ and ${\delta}D$ values of hot spring waters indicate that they originate from the meteoric water, and that the values also reflect a latitude effect according to their locations. $^3He/^4He$ ratios of the hot spring waters except Osaek $CO_2$-rich hot spring water range from $0.1{\times}10^{-6}$ to $1.1{\times}10^{-6}$ which are plotted above the mixing line between air and crustal components. It means that the He gas in hot spring waters was originated mainly from atmosphere and crust sources, and partly from mantle sources. The Osaek $CO_2$-rich hot spring water shows $3.3{\times}10^{-6}$ in $^3He/^4He$ ratio that is 2.4 times higher than those of atmosphere. It provides clearly a helium source from the deep mantle. $^{40}Ar/^{36}Ar$ ratios of hot spring water are in the range of an atmosphere source.

• Economic and Environmental Geology
• /
• v.39 no.4 s.179
• /
• pp.369-384
• /
• 2006

Korean Peninsula, located on the southeastern part of Eurasian plate, belongs to the intraplate region. The characteristics of intraplate earthquake show the low and rare seismicity and the sparse and irregular distribution of epicenters comparing to interplate earthquake. To evaluate the exact seismic activity in intraplate region, long-term seismic data including historical earthquake data should be archived. Fortunately the long-term historical earthquake records about 2,000 years are available in Korea Peninsula. By the analysis of this historical and instrumental earthquake data, seismic activity was very high in 16-18 centuries and is more active at the Yellow sea area than East sea area. Comparing to the high seismic activity of the north-eastern China in 16-18 centuries, it is inferred that seismic activity in two regions shows close relationship. Also general trend of epicenter distribution shows the SE-NW direction. In Korea Peninsula, the first seismic station was installed at Incheon in 1905 and 5 additional seismic stations were installed till 1943. There was no seismic station from 1945 to 1962, but a World Wide Standardized Seismograph was installed at Seoul in 1963. In 1990, Korean Meteorological Adminstration(KMA) had established centralized modem seismic network in real-time, consisted of 12 stations. After that time, many institutes tried to expand their own seismic networks in Korea Peninsula. Now KMA operates 35 velocity-type seismic stations and 75 accelerometers and Korea Institute of Geoscience and Mineral Resources operates 32 and 16 stations, respectively. Korea Institute of Nuclear Safety and Korea Electric Power Research Institute operate 4 and 13 stations, consisted of velocity-type and accelerometer. In and around the Korean Peninsula, 27 intraplate earthquake mechanisms since 1936 were analyzed to understand the regional stress orientation and tectonics. These earthquakes are largest ones in this century and may represent the characteristics of earthquake in this region. Focal mechanism of these earthquakes show predominant strike-slip faulting with small amount of thrust components. The average P-axis is almost horizontal ENE-WSW. In north-eastern China, strike-slip faulting is dominant and nearly horizontal average P-axis in ENE-WSW is very similar with the Korean Peninsula. On the other hand, in the eastern part of East Sea, thrust faulting is dominant and average P-axis is horizontal with ESE-WNW. This indicate that not only the subducting Pacific Plate in east but also the indenting Indian Plate controls earthquake mechanism in the far east of the Eurasian Plate. Crustal velocity model is very important to determine the hypocenters of the local earthquakes. But the crust model in and around Korean Peninsula is not clear till now, because the sufficient seismic data could not accumulated. To solve this problem, reflection and refraction seismic survey and seismic wave analysis method were simultaneously applied to two long cross-section traversing the southern Korean Peninsula since 2002. This survey should be continuously conducted.

• Journal of Korea Soil Environment Society
• /
• v.4 no.2
• /
• pp.113-125
• /
• 1999

Heavy metal elements were analysed to assess degrees of heavy metal contents for the plants, M. sinensis, A. vulgaris and G. oldhamiana, from the Baekdong serpentine area within the western part of Chungnam. The area was divided into two sites ; serpentine area (SP, consisting of serpentinite, SP) and non-serpentine area (NSP, containing amphibole schist, AS and gneiss, GN). Their host rocks(R) and top soils(S) were also collected from the each site. As the results of the study, the plants contain high concentration of Ni Cr, Co in the SP and Fe, Zn in the AS and GN. Plants from the AS of the NSP contain mainly high content in the most of elements. Averages of Ni, Co and Cr for the plants decreased in the order of SP, AS and GN. In the total element contents, M. sinensis and A. vulgaris decreased in the order of Fe > Ni or Cr > Zn > Co > As > Sc within the SP and in the order of Fe > Zn > Cr > Ni, within the GN. Comparing among the parts of plants, root parts were higher in the most of elements than the above grounds. In the relative element ratios of plants collected from the SP and GN (SP/GN) M. sinensis was lower than A. vulgaris in the most of elements, suggesting that the M. sinenis shows low absorption within the infertile serpentine soil and high absorption within the fertile gneiss soil. In the element contents of the top soils and their host rocks, the SP shows higher Ni, Co and Cr contents than the others. Their total contents decreased from SP to AS and GN, suggesting that the soils reflect the composition of their host rocks. Total element contents of the SP decreased in the order of Fe> Cr or Ni> Co> Zn> As> Sc and, for the GN, in the order of Fe> Zn> Cr> Ni> Co or Sc, respectively. In the relative element ratios, R/S of the SP decreased in the order of Cr> As> Fe> Sc> Co> Ni> Zn and for the GN, in the order of Sc> Fe> Ni> Zn> Cr> Co. Comparing with plants within the each site, their top soils were higher than the plants in the most of elements. and their increase and decrease trends for each element are similar. Differences of element contents between the top soils and plants decreased in the order of SP, AS and GN. Plants of the GN were moi-e similar to their soils than those of the others, suggesting that each plant species show different absorptions within the different soils. Comparing with the plants of GN, higher Ni, Co, Cr contents within those of the SP and their survival within the infertile serpentine soil suggest that the M. sinensis, A vulgaris and G. oldhamiana may be the tolerance species in the serpentine soil. Comparisons with the upper crust show that M. sinensis, and A. vulgaris within the SP show high Hi and Cr contents. suggestive of hyperaccumulation. Upper results with the previous studies for the contaminated soils developed as parent materials with the serpentinites suggest additional studies for ecological behaviors for the plant and degrees of accumulations for the elements need to know phytoextraction of the heavy metal elements within the soils.

• Economic and Environmental Geology
• /
• v.46 no.2
• /
• pp.179-198
• /
• 2013

The Boziguoer A-type granitoids in Baicheng County, Xinjiang, belong to the northern margin of the Tarim platform as well as the neighboring EW-oriented alkaline intrusive rocks. The rocks comprise an aegirine or arfvedsonite quartz alkali feldspar syenite, an aegirine or arfvedsonite alkali feldspar granite, and a biotite alkali feldspar syenite. The major rock-forming minerals are albite, K-feldspar, quartz, arfvedsonite, aegirine, and siderophyllite. The accessory minerals are mainly zircon, pyrochlore, thorite, fluorite, monazite, bastnaesite, xenotime, and astrophyllite. The chemical composition of the alkaline granitoids show that $SiO_2$ varies from 64.55% to 72.29% with a mean value of 67.32%, $Na_2O+K_2O$ is high (9.85~11.87%) with a mean of 11.14%, $K_2O$ is 2.39%~5.47% (mean = 4.73%), the $K_2O/Na_2O$ ratios are 0.31~0.96, $Al_2O_3$ ranges from 12.58% to 15.44%, and total $FeO^T$ is between 2.35% and 5.65%. CaO, MgO, MnO, and $TiO_2$ are low. The REE content is high and the total ${\sum}REE$ is $(263{\sim}1219){\times}10^{-6}$ (mean = $776{\times}10^{-6}$), showing LREE enrichment HREE depletion with strong negative Eu anomalies. In addition, the chondrite-normalized REE patterns of the alkaline granitoids belong to the "seagull" pattern of the right-type. The Zr content is $(113{\sim}1246){\times}10^{-6}$ (mean = $594{\times}10^{-6}$), Zr+Nb+Ce+Y is between $(478{\sim}2203){\times}10^{-6}$ with a mean of $1362{\times}10^{-6}$. Furthermore, the alkaline granitoids have high HFSE (Ga, Nb, Ta, Zr, and Hf) content and low LILE (Ba, K, and Sr) content. The Nb/Ta ratio varies from 7.23 to 32.59 (mean = 16.59) and the Zr/Hf ratio is 16.69~58.04 (mean = 36.80). The zircons are depleted in LREE and enriched in HREE. The chondrite-normalized REE patterns of the zircons are of the "seagull" pattern of the left-inclined type with strong negative Eu anomaly and without a Ce anomaly. The Boziguoer A-type granitoids share similar features with A1-type granites. The average temperature of the granitic magma was estimated at $832{\sim}839^{\circ}C$. The Boziguoer A-type granitoids show crust-mantle mixing and may have formed in an anorogenic intraplate tectonic setting under high-temperature, anhydrous, and low oxygen fugacity conditions.