• 한국해양학회지
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• v.30 no.3
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• pp.216-226
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• 1995

Stable isotopic and elemental compositions were analyzed for well- preserved calcareous skeletons (gastropods, pectenids, brachiopods, a scaphopod, and other bivalves) of the Pleistocene Seoguipo Formation from Cheju Island, Korea. Mineralogically and texturally, aragonitic and calcitic fossils still retain their original mineralogy and microstructure. High $\delta$$\^$18/O and $\delta$$\^$13/C contents indicate that the shells have not been altered by the post-burial diagenesis. Also, this is supported by high Na and Sr contents as well as low Mn and Fe compositions of the shells. Oxygen isotopic compositions of the well preserved fossils show that the organisms had lived under the lower paleotemperature or within the isotopically enriched paleo-seawater during the deposition of the Seoguipo Formation. This result strongly implies that the Seoguipo Formation was deposited during a glacial period. The paleotemperature variation throughout the sequence during the deposition of the Sewguipo Formation was negligible.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.56-62
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• 2001

울릉분지 남서부 해역에서 채취한 두 개의 피스톤 코어 (piston core) 시료를 이용하여 퇴적학 및 지화학적 특성을 연구하였다. 코어는 제4기말의 이질 퇴적물로 대부분 구성되어 있고, 테프라 (tephra layer)와 사질 퇴적물이 일부 협재되어 나타난다. 기존 확인된 울릉분지의 테프라를 이용하여 층서 대비를 한 결과, 두 코어는 대양보다는 높은 퇴적률 (10-12cm/kyr)을 갖는다. 이는 코어가 약 4만 4천년 전의 기록부터 시작하고 있음을 의미한다. 동위원소 층서 2 (마지막 빙기) 중에 형성된 구간에서는 저탁류의 영향을 많이 받은 여러 종류의 퇴적상들이 교호하여 나타난다. 코어의 하부 구간에서는 가스의 방출에 의하여 형성된 것으로 사료되는 수평균열이 다수 관찰된다. 두 코어에서 측정된 유기탄소 (organic carbon) 함량은 평균 $1.8\% $(0.1-4.5\%)$으로 열린 바다 (open sea) 퇴적물의 유기탄소 함량보다 높다. 이는 Termination I 시기 때 해수면 상승으로 인해 산소가 다소 결핍된 환경으로 전이되면서 유기탄소의 양이 증가하였음을 보여주는 것으로 해석된다.

• Economic and Environmental Geology
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• v.34 no.1
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• pp.71-88
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• 2001

The Geochemica] and isotope studies on the $CO_2$-rich water from the Shinchon area were carried out. The Shinchon $CO_2$-rich water belongs to Ca(Na)-$HCO_3$ type showing very high $P_{CO_{2}}$ ( $10^{-0.35}$ ~ $10^{0.29}$ atm) and TDS (835-3,144 mg/L). The results of geochemical and isotope analysis indicate that $CO_2$ gas is originated from the deep seated source such as mantle or magmatic gases. The $CO_2$-rich water was evolved by interaction with deep-seated granite and major water-rock interaction was dissolution of p]agioclase resulting high Na content of $CO_2$-rich water. Precipitation and dissolution of secondary calcite might be accompanied with the dissolution of plagioclase maintaining Na/Ca ratio. High contents of K and $SO_4$ indicate that the geochemical characteristics of $CO_2$-rich water were partially affected by interaction with upper sedimentary rock during uprising to surface. N03 and tritium contents suggest that the $CO_2$-rich water was mixed with low $CO_2$ groundwater at some locations. The oxygen-hydrogen isotopes show that all water samples were derived from meteoric waters and the $CO_2$-rich water was isotopically re-equilibrated with lighter $CO_2$ gas. Although some carbon isotope data show isotopically heavy values, carbon isotope data indicate that the $CO_2$ gas was possib]y derived by deep source.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.222-232
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• 2001

Secondary ion mass spectrometry (SIMS) uses focused high-speed primary ions to produce secondary ions from sample surface that are analyzed through a mass filter. SIMS is often called as ion microprobe, since it offers a micrometer-scale spatial resolution. Although the precision and accuracy of SIMS are not as good as many conventional mass spectrometers, it has several advantages such as small sample-size requirement, high spatial resolution and capability of in-situ analysis. In the field of geochemistry/cosmochemistry, SIMS is widely used for (1) stable isotope geochemistry of H, C, O, S, etc., (2) geochronology of U/Th-bearing minerals, (3) lateral distribution of trace elements in a mineral, and (4) discovery of presolar grains and investigation of their isotopic compositions.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.3 no.3
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• pp.124-141
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• 1998

The objectives of this study are to investigate the trace (minor) elemental and isotopic compositions of calcitic skeletons, such as barnacle, echinoid, branching and encrusting calcareous algae and oyster, from the eastern coast of Korean peninsula and Cheju Island, and to compare their variations with latitude, that is, the temperature of ambient seawater at which the skeletons grew. Articulated and encrusting red algae are composed of high-Mg calcite (7-21 mol% $MgCO_3$). Echinoids are also composed of high-Mg calcite (7-15 mol% $MgCO_3$). Whereas barnacles are composed of low-Mg calcite (1-5 mol% $MgCO_3$). The Mg compositions of articulated red algae, barnacle and oyster tend to increase with increasing water temperature, whereas those of encrusting red algae and echinoid do not show any trend. Sr compositions of articulated red algae, echinoid and barnacle tend to decrease with increasing water temperature, whereas those of encrusting red algae and oyster do not show any trend. Mn compositions of articulated red algae and encrusting red algae decrease with an increase of water temperature, whereas those of echinoid and barnacle do not show any trend. Fe compositions of articulated red algae tend to decrease with increasing water temperature, whereas those of encrusting red algae and oyster increase. Fe compositions of echinoid and barnacle do not show any trend with water temperature variations. Ba compositions of echinoid and low-magnesium calcitic skeletons do not show any trend with water temperature variations. Ba compositions of articulated red algae tend to decrease with increasing water temperature, whereas those of encrusting red algae increase. Cd and Pb compositions of all the skeletons tend to increase with increasing water temperature. Cu compositions of encrusting red algae increase with increasing water temperature, whereas articulated red algae, echinoid, barnacle and oyster do not show any trend. Zn compositions of high-magnesium calcitic skeletons and low-magnesium calcitic skeletons do not show any trend. Estimated water temperatures from oxygen isotopic data of all the skeletons except for the barnacle arc higher than the range of temperature of the shallow seawater of the East Sea and around Cheju Island. The oxygen isotopic compositions of oyster and echinoid are well clustered, and they do not show any trend with increasing water temperature. Therefore, this could reflect that the organisms have not secreted their shells in oxygen isotopic equilibrium with ambient seawater due to vital effect. Thus, the oxygen isotopic composition of barnacle can potentially be utilized for paleotemperature estimate whereas those of other organisms in this study may not be useful.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.3
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• pp.116-124
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• 2000

Geochemical and isotopic analyses were carried out to investigate hydrochemical characteristics, source of carbon species in the carbonated waters in South Korea. Most Korean carbonated waters from different geologic settings are characterized by a Ca-HCO$_3$type with a relatively low pH range from 5.3 to 6.3 (avg. 6.0). The concentrations of cations and anions in the carbonate waters are in the order of Ca$^{2＋}$>Na$^{＋}$>Mg$^{2＋}$>Si$^{4＋}$>Fe$^{2＋}$>K$^{＋}$ and HCO$_3$$^{－}$>SO$_4$$^{2－}$>Cl$^{－}$, respectively. The HCO$_3$$^{－}$ ion is more enriched in the carbonated water from the sedimentary rock and granitic rock of Mesozoic age in the Gyungsang basin(GII) and the Precambrian metamorphic rock and Jurassic granitic rocks of the Gyunggj massif in the Gangwon province(GⅠ) than those of the meta-sedimentary rock and granite in the Ogcheon zone(GⅢ). Based on the oxygen and hydrogen isotopic data, the carbonated waters are derived from the meteoric water, showing apparent latitude and altitude effects. The $delta$$^{13}$C values of carbon species in the carbonated water are in between -6.23 and 0.0 $textperthousand$, suggesting inorganic source of carbon originated from the carbonate mineral and carbonate rock in the aquifer.

• Korean Journal of Heritage: History & Science
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• v.39
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• pp.39-58
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• 2006

This study reviews recent shell midden studies in Korea. With more interest in biological materials, recent shell midden studies have attempted to reconstruct palaeoenvironment, and understand subsistence economy, the formation processes and function of sites and past culture. Especially, one of the major topics in prehistoric Korean shell midden studies is the transitional process from hunter-gatherer to farmer. To solve these questions related with shell middens, new sampling strategies and excavation techniques have been adopted. Analytical methods combined with scientifical technologies also have been introduced to shell middle studies. These methods indude stable isotope analyses(Oxygen isotope and Carbon and Nitrogen isotope analyses) and growth-line analysis, etc.

• 한국해양학회지
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• v.24 no.2
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• pp.69-78
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• 1989

Cultivated pearls, composed of aragonite crystals, show two distinctive layers: nacreous and conchiolin organic layers. Each aragonite crystal is surrounded by organic matrix, which probably consists of amino acids. Nucleus, surrounded by pearl layer, also consists of nacreous crystals, suggesting that there is a close mineralogical and ultrasturctural relationship between pearl and nucleus. Carbon isotopic values of cultivated pearls are within the range of marine carbonate carbon. Oxygen isotopic composition indicates that the temperature for the growth of pearl and pearl oyster ranges from 16.4 to $21.4^{\circ}C$ and from 15.5 to $24.8^{\circ}C$, corresponding to the summer temperature range of the cultivating area. Elemental composition of pearl, pearl oyster, and nucleus shows that there is a difference in chemical composition depending upon the original mineralogy and the chemical composition of water in which shells grow. Especially, a strong relationship exists between pearl and the inner layer of pearl oyster because both are composed of nacreous aragonite and formed in a shallow marine environment.

• Economic and Environmental Geology
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• v.38 no.6 s.175
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• pp.707-716
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• 2005

Organic geochemical analyses including Rock-Eval pyrolysis, elemental analysis and stable carbon isotope analysis were performed to evaluate the characteristics of organic matter in the ODP Leg 127 Site 794A sediments and to understand paleoceanographic changes. Based on the TOC contents, C/N ratio, HI vs. OI, $\delta^{13}C_{org}$ and C/S ratio, results imply that dark layers containing a large amount of terrigenous organic matter were deposited under the suboxic/anoxic conditions, whereas the light layers containing largely marine organic matter were deposited under the oxic conditions. These results indicate that increasing surface-productivity by the input of a large amount of terrigenous organic matter from adjacent continent led to the deposition of dark layers during the interglacial highstands, whereas marine primary production and dilution caused by Kosa from the China desert area led to the deposition of light layers with the decreased to terrigenous organic matter during the glacial lowstands.

• The Journal of the Petrological Society of Korea
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• v.12 no.3
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• pp.135-153
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• 2003

In order to understand its origin and petrogenesis, petrochemical studies of major, trace elements, REE, and stable isotopes of oxygen and carbon from the Hongcheon Fe-REE deposits have been investigated. The Hongcheon Fe-REE deposit intruding into Precambrian metasedimentary rocks consists of magnetite, various carbonates such as ankerite, siderite, magnesite and strontianite, monazite, aegirine-augite, Na-amphibole, and sulfides. Compared with major elements abundances of typical ferro-carbonatites, the Hongcheon Fe-REE deposit is enriched in FeO and depleted in CaO with increasing of $SiO_2$, where $TiO_2$and $A1_2O_3$increased and CaO, FeO, MgO and $P_2O_5$ are slightly decreased, but those are rather scattered and their trends are somewhat ambiguous. V Ni, U and Rb slightly increasing with of $SiO_2$increase and scattering or no trends of other detected elements. Nb, Zr and Zn are depleted then the abundances of typical ferro-carbonatites (Woolley and Kempe, 1989). In rare earth elements a large enrichment of total REE (maximum 14.8 wt%) and LREE relative to chondrites and HREE depleted more then the values of ferro-carbontites therefore La/Lu ratios shows large abundances (max. 16,197). The results of stable isotopes of O and C from minerals of ankerite and strontianite and whole rocks represent studied rocks are from igneous carbonatitic melts. Although petrochemical characteristics of the Hongcheon Fe-REE deposits are somewhat different from normal ferro-carbonatites from the world, this discrepancy suggests another conclusion that petrochemical characteristic of the studied Fe-REE mineralized rocks are similar to those of phoscorites from Kovdor, Russia and Sokli, Finland showing the same petrochemical compositions described above.