• Journal of The Geomorphological Association of Korea
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• v.19 no.4
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• pp.97-108
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• 2012

There exist plenty of geomorphological resources in Haean Basin, Yonghwasan Mt., and Gandong Basin in Eastern DMZ area in Gangwon Province which can be used as geotourism resources. Meticulous strategies are necessary to improve the geotourism bases in such a mountainous region. Potential geosites including Yongneup and Simjeog wetlands are nearby, so it is necessary to include these geosites when planning geotourism courses. The values of these sites coinciding with the goal of geopark are as follows: this region shows contrasting landforms derived from distinctive rocks such as gneiss and biotite granite, and there are many landforms derived from differential weathering of granite too. They can be used to explain the developmental history of numerous basin structures in entire Korean peninsula.

• Journal of the Korean association of regional geographers
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• v.8 no.4
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• pp.468-479
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• 2002

This study attempts to characterize Taebaek mountainous region as a natural unit, relating to morphoclimatic milieu and landform development patterns of the mountains of each lithologic type. In the case of granitic mountains of Nothern parts of this region, the slopes presents more or less steep or irregular profile because of abundant microforms of exposed bedrocks and blocks. The development of such landscape is essentially due to differential weathering, associated with difference of joint density. In the case of gneissic mountains, the slopes are well regularized straight steep ones, due not only to generalized superficial weathering but also to massmovement of weathered materials. In the Middle parts of this region, especially in Taegwallyong area, with frequent alternations both of freezing-thawing and of snow accumulation-melting, the roles played by cryo-nival processes proved to be important in weathering of granite as well as in morpho-pedogenesis. In this area, weathered mantle, developed by cryogenic activity under humid condition of nival environment, covered almost all over the slopes. Although Southern parts of this region consist of limestone, on the mountainous volume, distribution of Karst forms are limited while predominate none karst forms such as cockpit type peaks, V-shaped type valleys dissecting steep slopes covered with thin deposits in thickness containing rock debris.

• Geophysics and Geophysical Exploration
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• v.2 no.1
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• pp.1-7
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• 1999

We investigated the weathering characteristics of On-Yang gneiss by means of geological survey and Ground Penetrating Radar(GPR). The results of geological survey and boring show the two sets of vertical joint and horizontal joint developed by foliation which is composed of salic and melanic layers. GPR section evidently shows foliation direction and differential weathering due to discontinuity and mineral composition of metamorphic rock. The GPR section for instantaneous phase attribute based on complex trace analysis evidently shows continuity and foliation direction of metamorphic rock. The strong reflection amplitude which is derived from the banded structure of weathered rock can be incorrectly interpreted as a reflection of bedrock. The depth of rock basement should be estimated from the overall exploration result such as boring, seismic method, and electrical resistivity method.

• Economic and Environmental Geology
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• v.15 no.4
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• pp.205-219
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• 1982

The Eosangcheon manganese ore deposits occur as supergene weathering deposits along quartz porphyry dikes developed in the Ordovician Heungweolri dolomite and Samtaesan limestone formations. The manganese ores are composed of manganese oxide minerals and associated other minerals. Rancieite and todorokite are abundantly found, and birnessite, nsutite, pyrolusite and chalcophanite are found in minor quantities. Associated other minerals are calcite, gypsum, goethite, lepidocrosite, quartz, and sericite. Microscopic, chemical, X-ray powder diffraction, infrared absorption spectroscopic and differential thermal analyses have been made for manganese oxide minerals and associated other minerals. The relationship of birnessite and rancieite was studied by means of X-ray powder diffraction and infrared absorption spectroscopic analyses. It is assumed that these minerals are closely related to each other in crystal structure, but separate species. The manganese oxide minerals were formed mainly by replacement, precipitation from solution, and recrystallization in the supergene weathering environment. The trend of formation of manganese oxide minerals is: (Rhodochrosite)-(todorokite)-(birnessite, rancieite)-(nsutite, pyrolusite, chalcophanite).

• Korean Journal of Soil Science and Fertilizer
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• v.6 no.3
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• pp.141-152
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• 1973

The mineralogical studies of the eleven sub-soil samples derived from granite, granodiorite, diorite and arkose sandstone, taken from apple orchards in the province of Kyungsangbukdo, Korea are made to investigate the relationships between the mineral weathering, soil forming processes and mineralogical composition. The fine sand fraction (less than 0.2mm) and the clay fraction (less than 2 micron) are dispersed with the shaker after hydrogen peroxide treatment for the removal of organic matter, and separated from each suspension by gravity sedimentation. The fine sand are observed by mineral microscope and the clay are observed by X-ray diffraction patterns, differential thermal analysis curves and infrared spectrum. The outline of the results are as follows. 1. The primary minerals ; Quartz, changed-feldspar, plagioclase, alkali-feldspar are dominant in almost all samples, and some samples contain an appreciable amount of hornblende, biotite, muscovite and plant opal. There are also those samples which contain very small quantity of pyroxene group, tourmaline, epidote, cyanite, magnetite, volcanic glass and zircon. They are mainly derived from weathering products of granite, granodiorite, diorite, arkose or its mixtures. 2. All samples contain expanding or nonexpanding $14{\AA}$ minerals, illite and kaolin minerals, and some samples contain chlorite, cristobalite, gibbsite, and those primary minerals as quartz and feldspar, but the quantities vary according to the parent matrials. 3. Non-expanding $14{\AA}$ minerals may be dioctahadral vermiculite which sandwiches gibbsite layer or chlorite in between layer lattices. 4. As for clay minerals, montmorillonite was principal component in the samples derived from weathering products of arkose sandstone and tertiary. Minerals which are derived from weathering products of arkose have kaolin minerals and vermiculite as their principal component, and minerals derived from weathering products of acidic rock group are generally classified into two groups, the kaolin mineral group, and the kaolin minerals and vermiculite group.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.652-661
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• 2006

The cut slopes in Jinju area constitute the Cretaceous Sedimentary rock which is one of the most poor ground conditions. The geological rocks of the cut slopes are correlated with Jinju Formation. Most of the rocks consist of Black Shale layer, but the lower parts consist of Alkorsic White Sandstone. So, It is characteristic of the differential weathering due to the difference of rock species. Moreover, vertical joints which concentrate on the released rock and weak rock fragments are accompanied with minor faults. We make out face mapping about each slopes through the detailed field-study and deduce RMR and SMR from the field data. The strength properties of rocks were obtained from references, indoor tests, and Back Analysis method. And, choosing properties were used in the stability analysis as stereographic projection and limit equilibrium analysis and we establish the countermeasures for the cut slopes.

• Journal of Conservation Science
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• v.17 s.17
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• pp.83-94
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• 2005

Host rock or the standing sculptured Buddha in the Yongamsa temple is macular porphyritic biotite granite, which has gone through mechanical and chemical weathering. The rock around the Buddha statue is busily scattered with steep inclinations that are almost vertically discontinuous planes with the strikes of $N8^{\circ}E$. Especially the development of the joints that cross the major joints causes the structural instability of the rock. The rock of the Buddha statue is separated into several rock blocks because of many different discontinuity. Thus it is estimated that the bed rock has not only plane and toppling failure but also wedge failure in all the sides. Since the differential pressure is imposed on the body of the Buddha in the host rock, it is urgent to give a reinforce treatment of geotechnical engineering for the safe of its structural stability. Very contact area of joints have turned into soil, which promotes the growth of weeds and plant roots, then aggravates the mechanical weathering of the rock. Thus conservational treatments should also be considered to get rid of secondary contaminants and vegetation along the discontinuities and to prevent further damages.

• The Journal of Engineering Geology
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• v.33 no.3
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• pp.427-438
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• 2023

We carried out a geological survey to classify the types of mass movement in Danyang Geopark (where various rock types are distributed) and analyzed the mechanical and hydraulic characteristics of landslide materials using a series of laboratory tests. Debris flows occurred in areas of limestone/marble, shale, and porphyroblastic gneiss, and limestone/marble landslides were distinguished from the others through the presence of karren topography. Soil tests showed that soil derived from weathered gneiss, which has a higher proportion of coarse grains, has a higher friction angle, lower cohesion, and larger hydraulic conductivity than soils from areas of limestone/marble, and shale. Rock failure mass movements occurred in areas of phyllite, sandstone, and conglomerate and were subdivided into plane failure, block-fall, and boulder-fall types in areas of phyllite, sandstone, and conglomerate, respectively. The shear strength of phyllite is much lower than that of the other types of rock, which have similar rock quality. The slake durability index of the conglomerate is similar to that of the other rock types, which have similar degrees of weathering, but differential weathering of the matrix and clasts was clearly observed when comparing the samples before and after the test. This study can help establish appropriate reinforcement and disaster prevention measures, which depend on the type of mass movement expected given the geological characteristics of an area.

• The Korean Journal of Quaternary Research
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• v.1 no.1
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• pp.35-45
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• 1987

Several fluvial terraces were developed in the Kajo Basin located in Kochang-gun, Kyongsangnam-do, Korea. The peat layers are formed on a fluvial terrace of them. To clarify the geomorphic development of this basin, a detailed classification of geomorphic surfaces, a soil profile study, grain size analysis, pollen analysis of the peat layers and C-14 dating were made. The main findings are as follows: 1) The Kajo Basin was formed by a differential erosion of granic rocks. The surrounding mountains are contact-metamorphosed gneiss and sedimentary rocks. 2) Seven geomorphic surfaces were recognized. They are named the H1, H2, M1, M2, T, L1 and L2 surfaces, from older to younger. 3) C-14 dating and the pollen analysis indicate that the L1 surface was formed during the Early Wurm Glacial. 4) The formation periods of the L2, M and H surfaces are supposed to be the Late Wurm, Riss and Mindel glacial, respectively, on the basis of the color of soil horizons (with or without the Red Soil) and the weathering degree of gravels. 5) Betula and Pices were dominant in the pollen of the Kajo Basin around 30,000 years B.P.

• Journal of Conservation Science
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• v.11 no.1 s.14
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• pp.1-14
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• 2002

After the construction (1398 year at first, secondarily reconstructed at 1448 year), the Soongryemoon (South Gate) had been preserved to late 19c without large damages. The present shape of the gate have been kept after the repairments of two times (1953, 1963). However, the rocks constituting the walls of the gate have been strongly weathered, exfoliated and cracked due to severe changes in the environment as traffic increase, air pollution and the subway which may seem also to cause the structural unstability. The rocks composed of the walls of the gate are almost of granites. On the rocks such deteriorations as onion structure, surface exfoliation, cracks, and edge breakout are developed. These deteriorations may be caused genetically by strong weathering, differential load due to possibly structural unstability, impact and unknown reasons. For the establishment of conservation plan, the factors of these deterioration phenomena and structural unstability must be quantitatively analyzed and diagnosed in detail.