• The Journal of the Petrological Society of Korea
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• v.24 no.4
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• pp.307-321
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• 2015

The study area, Bophi Vum, Myanmar, is composed of the harzburgite, serpentinite and dunite, those are covered by Quaternary alluvium. The chromite ore bodies are developed within dunite and harzburgite bodies, mainly within dunite bodies. To identify the extension of the chromite ore bodies, we carried out trench surveys in the 5 different sites. The chromite ore bodies have 0.3-1.5 m wide, and several meters of extension, and deformed strongly as a sigmoid and a boudin shapes with dunite and harzburgite bodies by ductile deformation. The ductile deformation have a top-to-the-west shear sense, indicating the existence of a westward thrusting. The NW-SE trending distribution of ore bodies is related to the dextral ductile shearing and/or to the block rotation as a book-shelf structure by dextral strike-slip movement.

• The Journal of Engineering Geology
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• v.14 no.4 s.41
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• pp.451-460
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• 2004

The strength of sliding plane is usually assigned on the whole sliding plane with same value in 2D limit equilibrium slope stability method. However, the potential sliding plane is divided into two or three parts which have different sliding resistances. According to the calculation results of 3D slope stability analyses using 4 types of slope cutting models, marginal sliding resistance could affect the safety of slope significantly. In this calculation two kinds of the sliding plane strengths were applied differently to the parts of bottom and margin of the model slope. The effect of marginal resistance was calculated quantitatively. In case of lower sliding resistance of the bottom, the safety factor becomes low in a margin cutting model. However, in case of higher sliding resistance of the bottom, the safety factor decreased slightly in a lower part cutting model and increased in a upper margin cutting model.

• Journal of Conservation Science
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• v.29 no.3
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• pp.231-241
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• 2013

Analysis of the bronze bodhisattva from Pangyo-dong sites in Seongnam by computed tomography, ICP-AES, metallurgical microscope and SEM-EDS had to know manufacturing technique. And the origin of the raw material, was investigated using TIMS. Results with computed tomography, two bronze bodhisattva produced by lost-wax casting technique with hollow inside and could see the core of the inside. Result of component analysis and microstructure observation, material is alloy of copper-tin-lead and made by casting without artificial treatment. According to lead isotope ratio analysis result of bronze bodhisattva could be made into galena of the Gyeonggi massif in Korea South.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.3
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• pp.403-407
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• 2005

A study was conducted to evaluate the effect of substitution of the flour with Lycium chinense powder on the characteristics of yellow layer cake. Physical properties including specific gravity, specific volume, cake index and color were measured. Also, the hardness change during 6 storage days at 22℃ were measured. Even though the specific gravity of batter decreased significantly with respective addition of 12%, 16% and 20% Lycium chinense powder, the specific volume of cakes did not show difference except the case of 20% addition. The addition of Lycium chinense powder did not influence on cakes' appearance negatively except that of 20% cake. The crust became darker as the level of Lycium chinense powder increased. The crumb color turned into dark orange with addition of Lycium chinense powder, and the intensity became stronger as the level of Lycium chinense powder increased. Both 4% and 8% Lycium chinense powder cakes were scored as same as control in moistness and softness. And they were favored as much as control.

• The Journal of the Petrological Society of Korea
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• v.15 no.3 s.45
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• pp.119-127
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• 2006

Detrital zircons in iron-bearing quartzite of the Seosan Croup from southeastern part of the Cyeonggi Hassif were analysed for SHRIHP U-Pb ages. Among 42 analyses, 38 data yield concordant ages (less tan 10 % discordancy), and they concentrated at 1781~1898 Ma (n=19), $1781{\sim}1898\;Ma(n=19),\;1935{\sim}1941\;Ma(n=4),\;1996\;Ma,\;2120\;Ma\;2403{\sim}2459\;Ma(n=5)$, 2661 Ma and 3198 Ma. The data indicate that sedimentation of iron-bearing quartzite should be after ca 1.78 Ga (the youngest detrital zircon age), and argue against some of conventional idea that iron-bearing quartzite of the Seosan Group might be correlated with the Archean iron-bearing quartzite in the North China Craton.

• Economic and Environmental Geology
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• v.54 no.3
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• pp.389-397
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• 2021

Moryang Fault is geomorphologically observed as a linear fault valley from Angang through Moryang, Duckhyun and Wondong to Gimhae, and contacts with Yangsan Fault, being obliquely away to the east, at Angang disrict. The fault valley appears a V-shape feature with a width from 100 to 300 m, and has fragmental zones of the fault along the valley on a small scale. Nine fault-outcrop localities were found along the nine-kilometers valley between Daehyun-ri, Gyeongju, and Baenaemi-gogae, Yangdong-ri, Ulsan. The fault strikes the North-North-East to the Northeast and dips to the Northwest with high angles, and reveals it had been undergone predominantly sinistral reverse fault movement sense, left-lateral and right-lateral strike-slip sense in bedrocks. However, after unconsolidated sediments, there was the top-up-to-the-east dextral reverse fault movement.

• The Journal of Engineering Geology
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• v.26 no.1
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• pp.33-49
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• 2016

The study area, located in Sinam-ri, Ulsan, in the southeastern part of the Korean Peninsula, is mainly composed of hornblende granite (ca. 65 Ma). Fracturing and reactivation of a fault striking ENE-WSW was strongly controlled by the intrusion of a mafic dyke (ca. 44 Ma), which behaves as a discontinuity in the mechanically homogeneous pluton, increasing the instability of the basement in this area. A geometric and kinematic study undertaken to interpret the faults and fractures was performed in a trench excavated almost perpendicular to the orientation of the dyke. The analysis of structural elements, such as dykes, veins, and faults, is used to infer the deformation history and to determine the paleostress orientations at the time of formation of the structures. The deformation history established based on this analysis is as follows: (1) NNE-SSW, E-W, ENE-WSW, and NE-SW trending fractures had already developed in the pluton before dyke intrusion; (2) felsic dykes intruded under conditions of σ_Hmax oriented N-S and σ_Hmin oriented E-W; (3) mafic dykes intruded under conditions of σ_Hmax oriented E-W and σ_Hmin oriented N-S; (4) dextral reactivation of the main fault associated with the development of hydrothermal quartz veins under conditions of σ_Hmax oriented E-W and σ_Hmin oriented N-S; (5) sinistral reactivation of the main fault and high-angle normal faults under conditions of σ_Hmax oriented NE-SW and σ_Hmin oriented NW-SE; and (6) dextral reactivation of the main fault and NE-SW low-angle reverse faults under conditions of σ_Hmax oriented NW-SE and σ_Hmin oriented NE-SW. These results are consistent with the tectonic history of the Pohang-Ulsan block in the southeastern part of the Korean Peninsula, and indicates the tectonic deformation of the southern area of the Ulsan fault bounded by Yangsan fault was analogous to that of the Pohang-Ulsan area from the Cenozoic. This work greatly aids the selection of sites for critical facilities to prevent potential earthquake hazards in this area.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.277-290
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• 2016

Deep geological cross-sectional data is generally not common nor easy to construct, because it is expensive and requires a great deal of time. As a result, geological interpretations at depth are limited. Many scientists attempt to construct geological cross-sections at depth using geological surface data and geophysical data. In this paper, we suggest a method for constructing cross-sections from limited geological surface data in a target area. The reason for this study is to construct and interpret geological cros-sections at depth to evaluate heat flow anomaly along the Yangsan fault. The Yangsan Fault passes through the south-eastern part of the Korean Peninsula. The cross-section is constructed from Sangbukmyeon to Unchonmyeon passing perpendicularly through the Yangsan Fault System trending NW-SE direction. The geological cross-section is constructed using the following data: (1) Lithologic distributions and main structural elements. (2) Extensity of sedimentary rock and igneous rock, from field mapping. (3) Fault dimension calculated based on geometry of exposed surface rupture, and (4) Seismic and core logging data. The Yangsan Fault System is composed of the Jain fault, Milyang fault, Moryang fault, Yangsan fault, Dongnae fault, and Ingwang fault which strike NNE-SSW. According to field observation, the western section of the Yangsan fault bounded by igneous rocks and in the eastern section sedimentary rocks are dominant. Using surface fault length we infer that the Yangsan Fault System has developed to a depth of kilometers beneath the surface. According to seismic data, sedimentary rocks that are adjacent to the Yangsan fault are thin and getting thicker towards the east of the section. In this study we also suggest a new method to recognize faults using core loggings. This analysis could be used to estimate fault locations at different scales.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.485-505
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• 2022

On November 15, 2017, a Mw 5.4 Pohang Earthquake occurred at about 4 km hypocenter in the Heunghae area, and caused great damage to Pohang city, Korea. In the Heunghae area, which is the central part of the Pohang Basin, the Cretaceous Gyeongsang Supergroup and the Late Cretaceous to Early Paleogene Bulguksa igneous rocks as basement rocks and the Neogene Yeonil Group as the fillings of the Pohang Basin, are distributed. In this paper, structural and geological researches on the crustal deformations (folds, faults, joints) in the Pohang Basin and the coseismic ground deformations (sand volcanoes, ground cracks, pup-up structures) of Pohang Earthquake were carried out, and the deformation history of the Pohang Basin and characteristics of the coseismic ground deformations were considered. The crustal deformations were formed through at least five deformation stages before the Quaternary faulting: forming stages of the normal-slip (Gokgang fault) faults which strike (N)NE and dip at high angles, and the high-angle joints of E-W trend regionally recognized in Yeonil Group and the faults (sub)parallel to them, and the conjugate normal-slip faults (Heunghae fault and Hyeongsan fault) which strike E-W and dip at middle or low angles and the accompanying E-W folds, and the conjugate strike-slip faults dipped at high angles in which the (N)NW and E-W (NE) striking fault sets show the (reverse) sinistral and dextral strike-slips, respectively, and the conjugate reverse-slip faults in which the NNE and NNW striking fault sets dip at middle angles and the accompanying N-S folds. Sand volcanoes often exhibit linear arrangements (sub)parallel to ground cracks in the coseismic ground deformations. The N-S or (N)NE trending pop-up structures and ground cracks and E-W or (W)NW trending ground were formed by the reverse-slip movement of the earthquake source fault and the accompanying buckling folding of its hanging wall due to the maximum horizontal stress of the Pohang Earthquake source. These structural activities occurred extensively in the Heunghae area, which is at the hanging wall of the earthquake source fault, and caused enormous property damages here.

• Economic and Environmental Geology
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• v.45 no.3
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• pp.317-333
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• 2012

The Yeongweol Group is a Lower Paleozoic mixed carbonate-siliciclastic sequence in the Taebaeksan Basin of Korea, and consists of five lithologic formations: Sambangsan, Machari, Wagok, Mungok, and Yeongheung in ascending order. Sequence stratigraphic interpretation of the group indicates that initial flooding in the Yeongweol area of the Taebaeksan Basin resulted in basal siliciclastic-dominated sequences of the Sambangsan Formation during the Middle Cambrian. The accelerated sea-level rise in the late Middle to early Late Cambrian generated a mixed carbonate-siliciclastic slope or deep ramp sequence of shale, grainstone and breccia intercalations, representing the lower part of the Machari Formation. The continued rise of sea level in the Late Cambrian made substantial accommodation space and activated subtidal carbonate factory, forming carbonate-dominated subtidal platform sequence in the middle and upper parts of the Machari Formation. The overlying Wagok Formation might originally be a ramp carbonate sequence of subtidal ribbon carbonates and marls with conglomerates, deposited during the normal rise of relative sea level in the late Late Cambrian. The formation was affected by unstable dolomitization shortly after the deposition during the relative sea-level fall in the latest Cambrian or earliest Ordovician. Subsequently, it was extensively dolomitized under the deep burial diagenetic condition. During the Early Ordovician (Tremadocian), global transgression (viz. Sauk) was continued, and subtidal ramp deposition was sustained in the Yeongweol platform, forming the Mungok Formation. The formation is overlain by the peritidal carbonates of the Yeongheung Formation, and is stacked by cyclic sedimentation during the Early to Middle Ordovician (Arenigian to Caradocian). The lithologic change from subtidal ramp to peritidal facies is preserved at the uppermost part of the Mungok Formation. The transition between Sauk and Tippecanoe sequences is recognized within the middle part of the Yeongheung Formation as a minimum accommodation zone. The global eustatic fall in the earliest Middle Ordovician and the ensuing rise of relative sea level during the Darrwillian to Caradocian produced broadly-prograding peritidal carbonates of shallowing-upward cyclic successions within the Yeongheung Formation. The reconstructed relative sea-level curve of the Yeongweol platform is very similar to that of the Taebaek platform. This reveals that the Yeongweol platform experienced same tectonic movements with the Taebaek platform, and consequently that both platform sequences might be located in a body or somewhere separately in the margin of the North China platform. The significant differences in lithologic and stratigraphic successions imply that the Yeongweol platform was much far from the Taebaek platform and not associated with the Taebaek platform as a single depositional system. The Yeongweol platform was probably located in relatively open shallow marine environments, whereas the Taebaek platform was a part of the restricted embayments. During the late Paleozoic to early Mesozoic amalgamations of the Korean massifs, the Yeongweol platform was probably pushed against the Taebaek platform by the complex movement, forming fragmented platform sequences of the Taebaeksan Basin.