• Journal of the Korean Magnetic Resonance Society
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• v.6 no.2
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• pp.84-88
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• 2002

Dating and dosimetry using electron spin resonance (ESR) in 20th Century developed at both Yamaguchi University and Osaka University have been reviewed with emphasis on new prospects and strategies in 21th century. Natural radiation have been generating radicals that accumulated in archaeological and geological materials. ESR detects these radicals and the ESR signal intensity is proportional to the radiation dose and therefore the age. The assessment of the total dose of natural radiation and the annual dose rate give their ESR ages. The ESR dating of stalactites and stalagmites ant Akiyoshi cave in Yamaguchi prefecture in 1975 was extended to anthropological dating using bones and tooth enamel excavated in Greek Petralona cave. Fossils of shells and corals gave the ages of marine terraces and sea-level changes. Quartz grains gave the ages of geothermal alteration and fault movements. Future ESR dating of ices at outer planets anf their satellite are also investigated as basic studies for ices od $H_2O,\;CO_2,\;SO_2$ as well as terrestrial hydrates in laboratory. Atomic bomb radiation dosimetry at Hiroshima and Nagasaki using ESR lead to the dosimetry of personnel, Chemobyl and JCO criticality accidents. Monitoring of radiation dose with sensitive materials with tissue equivalence are being developed. finally a new scanning ESR imaging apparatus (a near field microwave microscope) developed in our laboratory gave ESR images of Radicals from fossils to Si-CVD and diamond films as summarized in my book in 2002.

• Economic and Environmental Geology
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• v.50 no.6
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• pp.445-466
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• 2017

Yeongdong area is located in the contact zone between central southeastern Ogcheon belt and Yeongnam massif, in which Cretaceous Yeongdong basin exists. Therefore, the study area has complex geological environment of various geological age and rock types such as Precambrian metamorphic rocks, age-unknown Ogcheon Supergroup, Paleozoic/Mesozoic sedimentary rocks, Mesozoic igneous rocks and Quaternary alluvial deposits. This study focuses on the link between the various geology and water type, and discussed the source of some major ions and their related water-rock interaction. For this study, the field parameters and ion concentrations for twenty alluvial/weathered and eighty bedrock aquifer wells were used. Statistical analysis indicates that there was no significant differences in groundwater quality between wet and dry seasons. Although various types were observed due to complex geology, 80 to 84 % of samples showed $Ca-HCO_3$ water type. Some wells placed in alluvial/weathered aquifers of Precambrian metamorphic and Jurassic granitic terrains showed somewhat elevated $NO_3$ and Cl concentrations. $Mg-HCO_3$ typed waters prevailed in Cretaceous Yeongdong sedimentary rocks. The deeper wells placed in bedrock aquifers showed complicated water types varying from $Ca-HCO_3$ through $Ca-Cl/SO_4/NO_3$ to $Na-HCO_3$ and Na-Cl type. Groundwater samples with $Na-HCO_3$ or Na-Cl types are generally high in F concentrations, indicating more influences of water-rock interaction within mineralized/hydrothermal alteration zone by Cretaceous porphyry or granites. This study revealed that many deep-seated aquifer had been contaminated by $NO_3$, especially prominent in Jurassic granites area. Based on molar ratios of $HCO_3/Ca$, $HCO_3/Na$, Na/Si, it can be inferred that Ca and $HCO_3$ components of most groundwater in alluvial/weathered aquifer wells were definitely related with dissolution of calcite. On the other hand, Ca and $HCO_3$ in bedrock aquifer seem to be due to dissolution of feldspar besides calcite. However, these molar ratios require other mechanism except simple weathering process causing feldspar to be broken into kaolinite. The origin of $HCO_3$ of some groundwater occurring in Cretaceous Yeongdong sedimentary rock area seems to be from dissolution of dolomite($MgCO_3$) or strontianite($SrCO_3$) as well.

• The Journal of the Petrological Society of Korea
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• v.16 no.4
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• pp.208-216
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• 2007

Based on digital geologic and geomorphic maps of 1 : 250,000 scale, distributive ratios of rock types were obtained by ArcGIS 9.0 program in the Gyeonggi, Seoul and Incheon areas of the Gyeonggi province. In the Gyeonggi area, 37 rock types are developed, and their geologic ages can be classified into Precambrian, Age-unknown, Triassic, Jurassic, Cretaceous and Quatemary. Among them, distributive ratios are decreasing in the order of Jurassic Daebo granites, Precambrian banded gneiss of Gyeonggi gneiss complex and Quatemary alluvium, all of which comprise about 83.7% of the rock types in the area. In the Seoul and Incheon areas, 10 and 15 rock types are developed, respectively., with the firmer being classified into Precambrian, Jurassic and Quatemary, and the latter into Precambrian, Jurassic, Cretaceous and Quatemary. In the Seoul area, distributive ratios are decreasing in the order of banded gneiss of Gyeonggi gneiss complex, Daebo granites and alluvium, which consist of 95.5% of the rocks in the area. In the Incheon area, distributive ratios are decreasing in the order of alluvium, Daebo granites, banded gneiss of Gyeonggi gneiss complex, reclaimed land, and schists of Gyeonggi gneiss complex, which occupy about 96.2% of the rocks in the area. The ratio of alluvium in the Incheon area is greater than that of Gyeonggi and Seoul areas, and the ratio of reclaimed land in the Incheon area is greater that of the Seoul, which can be attributed to the recent reclamation of the land for the industrial results such as new town development along the coastline of the Gyeonggi Bay.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.559-564
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• 1997

The New Hebrides Basin is an inactive non back-arc basin located at the convergent boundary of the Pacific and Info-Australian plates. This basin was formed from 46 Ma to 60 Ma. The basin has two spreading episodes with rates of 34 mm/a for 42 to 47 Ma and 17 mm/a for 47 to 60 Ma. The sediments covered in the basin has uniform thickness of 0.65 sec. The age-depth correlation curve of the New Hebrides Basin can be represented by the following equation: $Depth(m)=2689+312\sqrt{Age}(Ma)$ The coefficient of 312 in this equation is close to that for major oceans, 350. This suggests that the cooling processes of the lithospheres in the New Hebrides Basin and major oceans are similar to each other. Free-air gravity anomalies of the basin varying from -22.3 mgal to +59.0 mgal. The mean value is +30.2 mgal higher than those of the normal oceans. Moderately large free-air gravity anomalies in the New Hebrides Basin are presumably owing to its location on a marginal swell along the New Hebrides Trench. It is generally observed that the ocean floor is very gently uplifted in a zone about 200 km oceanward of the trench axis. Positive free-air gravity anomalies amounting to $50{\sim}60$ mgal are usually observed on the crest of the swell. This topography is presumably by bending of the oceanic lithosphere so as to dynamically maintain nonisostatic states for some duration.

• The Journal of the Petrological Society of Korea
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• v.24 no.3
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• pp.273-289
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• 2015

This study used the petrological features and the whole rock susceptibility characteristics suggest ways to determine the domestic dimension stones and Chinese similar dimension stones. In addition, this study compare the intrusive period by measuring the zircon U-Pb age of these stones. Result of comparing the petrological feature, with the exception of Macheon stone and Boryeong stone to show the differences in mineral composition and texture under a microscope, the domestic dimension stones and Chinese similar dimension stones exhibit substantially the same petrological feature. According to the measurement results for the whole rock magnetic susceptibility, Goheong, Iksan, Pocheon stones are the similar as Chinese dimension stones, and other stones are easily distinguished. The zircon U-Pb age results for Geochang, Iksan, and Pocheon stones are equivalent to the Jurassic Daebo granites and G603, G633, G655 are the Cretaceous granites. Therefore, the domestic dimension stones and Chinese similar dimension stones can be clearly determined by the zircon U-Pb age results.

• The Journal of the Petrological Society of Korea
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• v.24 no.4
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• pp.365-371
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• 2015

The rare earth element(REE)s play an important role in understanding of rock formation and evolution because of their similar geochemical behaviors. Sm and Nd are more useful than other REEs because Sm-Nd isotopic system has important applications for geochemical interpretation like age dating and crustal evolution. These studies require a chromatographic technique for Sm and Nd separation from the geological samples. Ln-resin method using 0.25 M HCl as the eluent is widely used for Nd separation. However, this technique has a disadvantage of the poor elemental selectivity that the Nd fraction contains Ce as a tailing of the previous fraction. This technical report is a comparison study on the effect of eluent concentration between 0.25 M HCl and 0.15 M HCl on the separation of Nd with Ln-resin method for improving the technique of Nd separation. The results showed that the separation of Ce and Nd using 0.15M HCl as the eluent was not effective compared to the separation using 0.25 M HCl. In this experiment, we could confirm that the dilution of eluent might not be effective on the high purity separation of Nd with Ln-resin method.

• Economic and Environmental Geology
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• v.44 no.1
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• pp.1-10
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• 2011

The geology of the Pacitan district which occupies Southern mountain zone in the southwestern margin of East Java, Indonesia, consists of a pile of clastics and pyroclastics grading upwards into a series of sediments of Middle Miocene age which are intruded by a number of quartz porphyries and subvolcanic dacitic to andesitic bodies in after that time. The geochemical exploration in the Pacitan district to find out anomalous areas related with metallic mineral dispersion from the concealed ore deposits had been carried out using traditional exploration techniques of geological mapping, stream sediment, panned concentrate and outcrop sampling. The anomalous zones of each element were detected in the following areas: Gempol for Cu; Jompong for Au; Kasihan for Cu-Pb-Zn. The strongest Cu-Pb-Zn anomalous values are overlapped at the Kasihan area. The geochemical survey of soil was conducted with the geological survey at the Kasihan area. The statistical values were calculated by the statistical analysis method. The patterns for Cu, Pb and Zn are similar to the normal distribution. The anomalous values of copper-lead-zinc and/or copper and zinc are overlapped at five zones surrounding quartz porphyry at the central part of the Kasihan area. The area was interpreted and chosen as an anomalous zone related with stockwork and skam mineralization, extending to approximately NNW-SSE direction.

• Spatial Information Research
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• v.8 no.1
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• pp.141-153
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• 2000

The purpose of this study is to develop and apply spatial landslide information system using Geographic information system (GIS) in concerned with spatial data. Landslide locations detected from interpretation of aerial photo and field survey, and topographic , soil , forest , and geological maps of the study area, Yongin were collected and constructed into spatial database using GIS. As landslide occurrence factors, slope, aspect and curvature of topography were calculated from the topographic database. Texture, material, drainage and effective thickness of soil were extracted from the soil database, and type, age, diameter and density of wood were extracted from the forest database. Lithology was extracted from the geological database, and land use was classified from the Landsat TM satellite image. In addition, landslide damageable objects such as building, road, rail and other facility were extracted from the topographic database. Landslide susceptibility was analyzed using the landslide occurrence factors by probability, logistic regression and neural network methods. The spatial landslide information system was developed to retrieve the constructed GIS database and landslide susceptibility . The system was developed using Arc View script language(Avenue), and consisted of pull-down and icon menus for easy use. Also, the constructed database can be retrieved through Internet World Wide Web (WWW) using Internet GIS technology.

• Economic and Environmental Geology
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• v.42 no.1
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• pp.9-25
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• 2009

The Northwestern Okcheon Metamorphic Belt in the Chungju area consists of the Munjuri Formation, the Daehyangsan Quartzite, the Hyangsanri Dolomite, and the Gyemyeongsan Formation, but the stratigraphy is still controversial. For a stratigraphic study, detailed stratigraphic sections were measured in two locations and mapping was carried out in the study area. The Munjuri Formation and the Daehyangsan Quartzite changed gradually in north and south section, but bedding parallel faults have developed in the boundary between two formations. The Daehyangsan Quartzite and the Hyangsanri Dolomite are conformable. Fault have developed in boundary between the Hyangsanri Dolomite and the Gyemyeongsan Formation. As a result of mapping in the study area, folding was recognized with $41^{\circ}/280^{\circ}$ plunging axis in the north part of the study area. Therefore, the bedding-parallel faults in the boundary might have occurred resulting from a layer parallel slip during the folding as well as the thrust. These results from this study and previous studies indicate that bedding-parallel faults in boundary between the Munjuri Formation and the Daehyangsan Quartzite are caused by a layer parallel slip during the folding. The fault between the Hyangsanri Dolomite and the Gyemyeongsan Formation is considered as a thrust fault, thereby the uppermost Gyemyeongsan Formation is placed under the Munjuri Formation. However the Gyemyeongsan Formation and the Munjuri Formation have similar age and rock composition. Hence, the Gyemyeongsan Formation is considered as an equivalent one with the Munjuri Formation. Therefore, the stratigraphy of Northwestern Okcheon Metamorphic Belt consists of the Gyemyeongsan/ Munjuri formations, the Daehyangsan Quartzite, and the Hyangsanri Dolomite in ascending order.

• Journal of the Geological Society of Korea
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• v.54 no.6
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• pp.631-640
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• 2018

To understand the formation and evolution of a sedimentary basin in basin analysis and modelling studies, it is important to analyze the thickness and age range of sedimentary layers infilling a basin. Because the compaction effect reduces the thickness of sedimentary layers during burial, basin modelling studies typically restore the reduced thickness using the relation of porosity and depth (compaction trend). Based on the compilation plots of published compaction trends of representative sedimentary rocks (sandstone, shale and carbonate), this study estimates the compaction trend ranges with exponential curves and equations. Numerical analysis of sedimentary compaction is performed to evaluate the variation of porosity and layer thickness with depth at key curves within the compaction trend ranges. In sandstone, initial porosity lies in a narrow range and decreases steadily with increasing depth, which results in relatively constant thickness variations. For shale, the porosity variation shows two phases which are fast reduction until ~2,000 m in depth and slow reduction at deeper burial, which corresponds to the thickness variation pattern of shale layers. Carbonate compaction is characterized by widely distributed porosity values, which results in highly varying layer thickness with depth. This numerical compaction analysis presents quantitatively the characteristics of porosity and layer thickness variation of each lithology, which influence on layer thickness reconstruction, subsidence and thermal effect analyses to understand the basin formation and evolution. This work demonstrates that the compaction trend is an important factor in basin modelling and underlines the need for appropriate application of porosity data to produce accurate analysis outcomes.