• Journal of The Geomorphological Association of Korea
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• v.26 no.3
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• pp.1-17
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• 2019

Naeseongcheon is Korea's representative sand stream, and it is one of the regions where the dynamic changes of various river topography developed in the sand bed can be observed. Most of drainage area near of the river channel are formed with Daebo granite, and the granite weathering zone is developed at the surface of hill. Due to the massive input of sediment flux, braided channel reaches are found some of the area. However, the results of the study shows that the alluvial layer is very thin in some reaches. In addition, bedrock or weathered materials, including the Tors are exposed at the channel beds. On the other hand, during the flood, a considerable amount of sediment was introduced, causing the massive sediment to be close to 1m thick. In addition, despite the short distance, large changes in the particle size and sorting of the sediment were observed. Vegetation, on the other hand, has been shown to have a significant effect on the development of the overall channel bed topography, as reported in previous studies. In small floods or low water levels, vegetation's protection role of the surface is predominates, but in large flood conditions, herbaceous loss at the surface of the point bars, accelerating the erosion of surface.

• The Journal of the Petrological Society of Korea
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• v.21 no.2
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• pp.129-150
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• 2012

The tectonic evolution of the Central Ogcheon Belt has been newly analyzed in this paper from the detailed geological maps by lithofacies classification, the development processes of geological structures, microstructures, and the time-relationship between deformation and metamorphism in the Ogcheon, Cheongsan, Mungyeong Buunnyeong, Busan areas, Korea and the fossil and radiometric age data of the Ogcheon Supergroup(OSG). The 1st tectonic phase($D^*$) is marked by the rifting of the original Gyeonggi Massif into North Gyeonggi Massif(present Gyeonggi Massif) and South Gyeonggi Massif (Bakdallyeong and Busan gneiss complexes). The Joseon Supergroup(JSG) and the lower unit(quartzose psammitic, pelitic, calcareous and basic rocks) of OSG were deposited in the Ogcheon rift basin during Early Paleozoic time, and the Pyeongan Supergroup(PSG) and its upper unit(conglomerate and pelitic rocks and acidic rocks) appeared in Late Paleozoic time. The 2nd tectonic phase(Ogcheon-Cheongsan phase/Songnim orogeny: D1), which occurred during Late Permian-Middle Triassic age, is characterized by the closing of Ogcheon rift basin(= the coupling of the North and South Gyeonggi Massifs) in the earlier phase(Ogcheon subphase: D1a), and by the coupling of South China block(Gyeonggi Massif and Ogcheon Zone) and North China block(Yeongnam Massif and Taebaksan Zone) in the later phase(Cheongsan subphase: D1b). At the earlier stage of D1a occurred the M1 medium-pressure type metamorphism of OSG related to the growth of coarse biotites, garnets, staurolites. At its later stage, the medium-pressure type metamorphic rocks were exhumed as some nappes with SE-vergence, and the giant-scale sheath fold, regional foliation, stretching lineation were formed in the OSG. At the D1b subphase which occurs under (N)NE-(S)SW compression, the thrusts with NNE- or/and SSW-vergence were formed in the front and rear parts of couple, and the NNE-trending Cheongsan shear zone of dextral strike-slip and the NNE-trending upright folds of the JSG and PSG were also formed in its flank part, and Daedong basin was built in Korean Peninsula. After that, Daedong Group(DG) of the Late Triassic-Early Jurassic was deposited. The 3rd tectonic phase(Honam phase/Daebo orogeny: D2) occurred by the transpression tectonics of NNE-trending Honam dextral strike-slip shearing in Early~Late Jurassic time, and formed the asymmetric crenulated fold in the OSG and the NNE-trending recumbent folds in the JSG and PSG and the thrust faults with ESE-vergence in which pre-Late Triassic Supergroups override DG. The M2 contact metamorphism of andalusite-sillimanite type by the intrusion of Daebo granitoids occurred at the D2 intertectonic phase of Middle Jurassic age. The 4th tectonic phase(Cheongmari phase: D3) occurred under the N-S compression at Early Cretaceous time, and formed the pull-apart Cretaceous sedimentary basins accompanying the NNE-trending sinistral strike-slip shearing. The M3 retrograde metamorphism of OSG associated with the crystallization of chlorite porphyroblasts mainly occurred after the D2. After the D3, the sinistral displacement(Geumgang phase: D4) occurred along the Geumgang fault accompanied with the giant-scale Geumgang drag fold with its parasitic kink folds in the Ogcheon area. These folds are intruded by acidic dykes of Late Cretaceous age.

• The Journal of Engineering Geology
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• v.24 no.3
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• pp.311-322
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• 2014

Limestone bodies under the tectonic environment have experienced various tectonic processes, and also changed the stress state. In this study, calcite twins found in limestones of the Joseon Supergroup and Pyeongan Supergroup in the northeastern part of the Ogcheon Belt, South Korea were measured, then the paleostress (i.e., the maximum shortening axis) was reconstructed using the new calcite strain gauge (NCSG) technique. The average twin thickness and average twin intensity increase as the total twin strain increases. We utilize the appearance of twins, the average twin thickness and average twin intensity, and the total twin strain to estimate that the observed calcite twins were produced at temperatures of < $200^{\circ}C$ in the Joseon Supergroup and $170^{\circ}C$ in the Pyeongan Supergroup. In the Joseon Supergroup, the dominant direction of the maximum shortening axis WNW-ESE to NW-SE; NE-SW shortening is also observed. The maximum shortening axes in the Pyeongan Supergroup are oriented NW-SE and NE-SW. The NE-SW direction of maximum shortening is associated with the occurrence of the Songrim orogeny of the Paleozoic to Early Jurassic, and the NW-SE direction of maximum shortening correlates to the Daebo orogeny of the Early Jurassic to Late Jurassic. It is thus concluded that the paleostress across the study area changed from NE-SW to NW-SE during the Mesozoic.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.119-122
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• 1998

Chemical analysis, measurement of pumping rates of 60 production wells and depth to water tables of 57 monitoring wells were carried to protect depletion of water resources and deterioration of water quality for the commercial portable ground-water. Borehole depth of production well averages 149m(31 boreholes), casing depth is 28m(29 boreholes), production rate is 70 $m^3$/day and depth to water table of monitoring well is 23.26m, respectively. The geology of 60 wells can be divided into Daebo granite(20), Okchun metarmorphic complex(18), Precambrian granitic gneiss(15), Bulguksa granite(4), Cheju volcanics(2), Cretaceous sedimentary rock(1). Average electrical conductivity and pH are 152$\mu$S/cm, and 7.35, respectively. The contents of major cation and anion predominantly $Ca^{2+}$>N $a^{+}$>M $g^{2+}$> $K^{+}$ and HC $O_{3}$$^{－}$ >S $O_{4}$$^{2-}$>Cl￣>F￣. Water type is predominantly $Ca^{2+}$-HC $O_{3}$$^{－}$(81.7%). It's possible that water chemistry of some wells were affected not only by the geology of boreholes penetrated but by inflows of surface water or shallow ground-water. Therefore, it is strongly necessary to steadily monitor the water quality and hydrogeologic conditins of production wells.ells.ls.ells.

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.760-765
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• 2018

In order to observe physical properties of rice depending on reheating, the study cooked rice developed for high quality cooked rice and analyzed physical properties of rice depending on reheating following 24 hr refrigeration. As a result of palatability of cooked rice, Samgkwang had the lowest hardness, while Daebo and Haiami had the highest one. With respect to adhesiveness, toughness and stickiness, Sindongjin exhibited lowest properties. After cooking each rice by cultivars, the study observed their color, texture properties, and microstructure immediately after cooking, after 24 hr of refrigeration and further on. Lightness of cooked rice tended to drop because of refrigeration and reheating. Analysis of texture properties after cooking revealed that Haiami marked the highest points in all categories. When stored for 24 hr after cooking, hardness, viscosity and chewiness increased in cooked rice followed by a decrease after reheating. Observation of the microstructure of cooked rice using a scanning electron microscope revealed that Haiami had its particles in the center as closely condensed. It was apparent that all the cultivars formed stoma in an obvious manner because of refrigeration and reheating. The results of the present study show that physical properties of cooked rice varied according to reheating after cooking and storage depending on the inherent characteristics of rice cultivars.

• Economic and Environmental Geology
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• v.47 no.2
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• pp.107-119
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• 2014

NMC Moland mine, which is classified as a contact replacement or skarn deposit, has been interpreted to have been formed by Daebo igneous activity which intruded into the Joseon Supergroup, because it is quite closely located to Jecheon granite. However, an alternative interpretation was recently suggested that the mine could be related with the hydrothermal fluid originated from Cretaceous granitic rocks, bringing about skarnization and Mo mineralization. Here we present an interpretation on the source granite of the mine based on the gravity exploration: the gravity anomaly, unlike the surface geology, shows that the Muamsa granite could be the related granite of the mine, because its hidden subsurface structure is expected to be more widely extended to surrounding area of the mine and deeper than the Jecheon granite.

• Economic and Environmental Geology
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• v.18 no.4
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• pp.381-397
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• 1985

A petrological study has been done in the pyeongchang-Jaecheon area which is a northwestern part of the basement of Ogcheon zone for the purpose of comparison of the area to the Nogjeon-Yeongchun area which is the antipodal basement of the zone in the petrological and geotectonical view points. The major units of the area are Precambrian granitic gneissic complex, banded gneiss, linea ted leucocratic gneiss and pegmatitic leucogranitic gneiss in the west, elongated exposure of quartz schist (or partly quartzite) and phyllite, named as Jungdaegal-bong Group correlated to the lower sequence of Joseon Group, in the middle, and limestone and calcic dolomite, Iptanri Formation, correlated to the middle of Joseon Group in the east. Igneous plutons are distributed in the areas of gneissic complex and limestone formation as well as in the Eosangcheon and Daedaeri areas in the southeastern out of the area. Present study reveals that the gneissic complex are the products of granitization to metamorphism of amphibolite facies in the order of above mentioned from the metasediments of schists and calcareous rocks. A notable characteristics of the phyllite of Jungdaegal-bong Group is the presence of syntectonically segregated quartz rods in the forms of lens, swirl or boudinage in evenly distributed in the phyllitic to chloritic matrix. Igneous rocks range in composition from gabbro through diorite, granodiorite, to schistosed and porphyritic granites in stock and dike. The orogenic movement of the Ogcheon zone initiated in the middle Proterozoic time, pre-sedimentation of Ogcheon Group and superposed the granitization in Permian, Jurassic Daebo orogeny with granitic batholiths and stocks, and Cretaceous plutonic intrusion.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.455-470
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• 1996

Mesozoic granitic rocks in the Korean peninsula contain $H_2$, $CH_4$, CO and rare $C_2H_6$. The Jurassic Daebo granites mostly belonging to the ilmenite series are predominated in $CH_4$. Meanwhile, the magnetite series Bulguksa granites of Cretaceous age in the Kyongsang basin and Okchon zone are relatively enriched in $CO_2$. The older granites have a wide variation of $CH_4/CO_2$ ratios (0.1~1.0) compared to those of the younger ones (0.1~0.5). This characteristics of gas compositions suggest that the Jurassic granites are principally derived from the partial melting of metasedimentary rocks with much reducing materials in the lower continental crust. On the other hand, the mantle source granitic magmas might be responsible for the Cretaceous granites characterized by dominant and homogeneous $CO_2$ gas compositions. Liquid-vapor homogenization temperatures of quartz in the Jurassic and Cretaceous granites range from 108 to $539^{\circ}C$ (av. $324^{\circ}C$) and 160 to $556^{\circ}C$ (av. $358^{\circ}C$), respectively. Their salinities are between 0.2 and 16.3 wt.% NaCl for the Jurassic granites and 0.4, and 15.6 wt.% NaCl for the Cretaceous ones. Fluid inclusions with solid daughter minerals lying on or near the halite equilibrium curve represent inclusion fluids from the magmatic stage. The type I and II fluid inclusions which are plotted apart from the equilibrium curve are considered to trap in late hydrothermal alteration stage with a increasing influx of metedric water.

• Economic and Environmental Geology
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• v.23 no.4
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• pp.453-463
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• 1990

The Yechon shear zone developed by strike-slip movement was formed in a relatively high temperature condition just after the Jurassic syntectonic granites had been emplaced during Daebo Orogeny. Post-emplacement formation of the shear zone is favored by continuity of foliations and lineations within and without the granites, development of mylonitic structures in the wallrocks, deformation of pegmatite and felsite dikes, and pretectonic growth of porphyroblasts in the wallrocks. A variety of shear sense indicators in the shear zone are predominantly observed in the intensely to extremely deformed rocks. They show that bulk non-coaxial detormation has occurred, and that the sense of shear is consistently dextral with S-C fabrics, grain shape fabrics, asymmetric porphyroclast systems, mica fish, asymmetric extension structures and quartz C-axis fabrics.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.01a
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• pp.283-286
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• 2014

본 논문에서는 카메라형 OCR (Optical Character Reader) 기술을 이용해 오프라인 중고서점의 효율적 장서관리 시스템을 구축하기 위한 디지털 데이터화 관리시스템 방안을 제안한다. OCR은 광학적으로 인식할 수 있는 문자를 컴퓨터가 읽을 수 있도록 하는 기술이다. 원리적으로 문자 한 개를 수십 개의 모눈으로 분할해 특정한 모눈의 흑백 또는 자획형상 특징에 의해 문자를 판독한다. 이 논문에서는 OCR 기술을 활용함으로써 디지털 데이터화의 효과는 물론 적용 환경의 개선효과를 기대해 볼 수 있는 오프라인 중고서점 시장을 목표로 했다. 오프라인 중고서점에서 보유하고 있는 장서의 디지털 데이터화는 기업형 중고서점과의 경쟁에 있어서도 생존을 위해 필요한 요소이다. 카메라형 OCR 기술을 활용한 장서 디지털 데이터화는 오프라인 중고서점 판매자가 도서재고 검색 및 판매 관리 효율을 높이도록 도와줄 뿐 아니라, 도서판매 유형, 소비자 분석과 수요 예측을 가능하게 한다. 또한 소비자에게 오프라인 중고서점에서 보유하고 있는 희귀 장서와 중고서적들을 검색해 구입할 수 있는 편의를 제공할 것이다. 오프라인 중고서점 판매를 촉진하고 활성화시킨다면 출판의 선순환적 구조를 만드는 데 기여할 것으로 예상된다.