• Proceedings of the Korean Geotechical Society Conference
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• 2002.11b
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• pp.31-50
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• 2002

The sedimentary rocks deposited in Taegu and Kyongbuk region consist of various rocks such as the shale, mudstone, siltstone and sandstone. The characteristics of the sedimentary rocks are distinguished from those of igneous rocks and metamorphy rocks for the stratum caused by deposit environment. This study investigated engineering characteristics of the anisotropy, weathering rock and filled rock joints in the notable features of sedimentary rocks.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.397-407
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• 2022

Mineralogical analysis of the bedrock of the Gobi Desert in southern Mongolia, the source of Asian dust, was conducted to trace the geological origin of the constituent minerals of Asian dust. The bedrock of the source of Asian dust consists of Paleozoic volcanics and volcaniclastic sedimentary rocks, Paleozoic granitic rocks, and Mesozoic sedimentary rocks. Paleozoic volcanics and volcaniclastic sediments lithified compactly, underwent greenschist metamorphism, and deformed to form mountain ranges. Mesozoic sedimentary rocks fill the basin between the mountain ranges of Paleozoic strata. In comparison to Paleozoic volcanic and sedimentary rocks, Mesozoic sedimentary rocks have lower contents of chlorite and plagioclase, but high contents of clay minerals including interstratified illite-smectite, smectite, and kaolinite. Paleozoic granites characteristically contain amphibole and biotite. Compared with the mineral composition of bedrock in source, Asian dust is a mixture of detrital particles originating from Paleozoic and Mesozoic bedrocks. However, the mineral composition of Mesozoic sedimentary rocks is closer to that of Asian dust. Less lithified Mesozoic sedimentary rocks easily disintegrated to form silty soils which are deflated to form Asian dust.

• Economic and Environmental Geology
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• v.5 no.1
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• pp.1-20
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• 1972

A large anorthositic mass outcropped as mushroom-like body extending up to 46km which occurs in the Hadong kaoline district of southern Korea. The anorthositic mass is in contact with the metamorphic, plutonic and sedimentary rocks. The metamorphic rocks are of granitic gneiss and banded gneiss, etc; the plutonic rocks are of gabbroic and dioritic rocks, schistose granite, syenite, diorite and granite. The sedimentary rocks include siltstone and pebbly sandstone of Lower Gyeongsang System, Cretaceous in age. The anorthositic mass shows a gradational contact with the metamorphic and sedimentary rocks, and is cut by the plutonic rocks except gabbroic and dioritic rocks. The anorthositic mass is leucocratic in the central portion of the mass, and, in turn, grades to rock phases in which ma/ic minerals are irregularly scattered, then to the well-lineated rock and finally to the banded gneiss. Lineation of the anorthositic mass is accordant with that of the surrounding banded gneiss, and the lineation continues toward the gneiss. In some places, the rock phases in which mafics are scattered is gradational with adjacent sedimentary rocks. The anorthositic mass in contact with gabbroic and dioritic rocks shows spotted features. Various replacement features seen under the microscope and paragenetic sequence of the mineral components in the anorthositic rocks cannot be considered as the origin of magmatic crystallization. From the field and microscopic observations, it is concluded that the anorthositic mass was formed from replacement of the metamorphic rocks and plutonic rocks by the anorthositic magma.

• Journal of The Geomorphological Association of Korea
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• v.28 no.1
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• pp.1-12
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• 2021

This study tried to reveal relative surface denudation resistance and ranking by geologic types in the Southern Korean Peninsula using an 1:250,000 digital geologic map and ASTER GDEM. Among rock types such as igneous, sedimentary and metamorphic rocks, metamorphic rock showed the greatest resistance to surface denudation. The most resistant rock to surface denudation by geologic periods (e.g., the Precambrian, Paleozoic, Mesozoic and Cenozoic) was found from the Precambrian. Among the major tectonic settings in the Southern Korean Peninsula such as the Gyeonggi massif, Okcheon belt, Yeongnam massif, Gyeongsang basin and Pohang basin, the Okcheon belt indicated the greatest resistance. The most and least resistant rocks from the representative nine rocks in the Southern Korean Peninsula were Paleozoic limestone, and Cretaceous sedimentary rock and Cenozoic sedimentary rock, respectively. This study suggests that Paleozoic limestone, Cretaceous volcanic rock, Paleozoic sedimentary rock and Precambrian gneiss can be regarded as hard rocks with high elevation, steep slope and complicated relief, while soft rocks with low elevation, gentle slope and simple relief are Jurassic granite, Cretaceous sedimentary rock and Cenozoic sedimentary rock.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.999-1008
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• 2009

A series of sedimentary rocks which are formed in the Tertiary are distributed around Samcheok(Samcheok-Pukpyoung basin), Younghae(Younghae basin), Pohang(Pohang basin), Gyeongju(Yangnam basin), Ulsan(Ulsan basin), Jeju(Seogyuipo formation) in the southern region of the Korean Peninsula. This study concerned with geological, geophysical, geotechnical properties of the unconsolidated rocks in the Pohang area. A consolidated rocks are classified as hard rock - soft rock - weathered rock - residual soil follows in degree of weathering. But unconsolidated rocks has soil properties as well as rock's at the same time. The results of field excursion, boring, borehole-logging, rock testing, geophysical survey, laboratory test are soft rock range, but the durability of the rock until the residual soil from the weathered rock. We accomplished the rock mass classification of the unconsolidated rocks.

• Economic and Environmental Geology
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• v.9 no.1
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• pp.13-26
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• 1976

The basic rocks distributed in the Okchon paleogeosynclinal zone have been previously considered as intrusive in majority, but as sedimentary parensis in few variety. The present study is to find out some clues to conclude otherwise, if any, by clarifying 1) the nature and characteristics of the rocks, 2) type of the associated sedimentary rocks if any, and 3) their occurrence in related to regional geologic structure. The finding are as follows: 1) The basic rocks are identified and classified to hornblende gabbro, amphibolite, basalt and andesite (in part metamorphosed to meta-volcanics), green schist and peridotite(which appears in separate locality from the others). 2) Associated sedimentary rocks which appear to overlie the basic rocks are known as Kunjasan and Baekwhasan formations. The two formations are probably same, but been used differently by different authers at different localities. The rocks is exclusively consisted of cherty looking siliceous quartzite and some localitis it shows very calcarious nature. The formation seems to indicate a sort of pelagic siliceous sediments although it contain some pebbles. 3) The basic rock suites are always underlain by the same continuous, great thrust, which separates the Okchon paleogeosyncline zone from the neogeosynclinal zone in the area studied. The comparison of Okchon basic rocks suite to the ophiolite suites in other parts of the world indicates some similarity with which the writers suggested the probalility of Okchon basic rocks being ophiolites that occur along ancient geosuture line now represented by the great thrust.

• The Journal of the Petrological Society of Korea
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• v.12 no.2
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• pp.70-78
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• 2003

Sado, Chudo, Mokdo, Nangdo, and Jeokgeumdo are the islands which belong to Hwajeong-myeon, Yeosu-si, Jeollanam-do and there are various kinds of volcanic rocks, volcaniclastic sedimentary rocks, and dinosaur-fossil bearing sedimentary rocks on these islands. This study is designed to constrain geologic ages of these volcanic and sedimentary rocks. K-Ar ages of these rocks indicate that the volcanism of this area occurred mainly during the period of 91.8 ${\pm}$ 3.5∼65.5 ${\pm}$ 1.3(l$\sigma$) Ma. Deposition ages of the sedimentary rocks were bracketed based on the ages of the volcanic rocks and observed field relationship between sedimentary and volcanic rocks. The oldest sedimentary deposit of the area is the volcanic pebble bearing conglomerate of the Jeokgeumdo and its deposition age is ca. 81 Ma or less. The deposition age of the Chudo shale, which belongs to stratigraphically upper sequence and bears many dinosaur footprints, is at least ca. 77 Ma. Conglomerate of the Mokdo was deposited at ca. 72∼70 Ma. The deposition age of the dinosaur fossil deposit of the Sado is at least ca. 65 Ma. All the investigated volcanic and sedimentary rocks of the Yeosu islands were formed during the late Cretaceous and dinosaurs lived until the latest Cretaceous in this area.

• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.23-35
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• 2004

The weathering characteristics of periodically submerged sedimentary rocks in the Sayeon dam, Ulsan was examined by field work, electron probe micro-analysis, X-ray diffraction, and X-ray fluorescence spectrometry. Analysis of fracture zone and exfoliation showed the submerged sedimentary rocks have undergone severe mechanical weathering. Mechanical weathering in the water-rock interface accelerated chemical weathering, such as dissolution and alteration of the most of minerals except for quartz in the weathering zone. The dissolution of carbonates specially calcite, is remarkable creating the cavities, whereas formation of minerals including clay minerals is not active. The sedimentary rocks have been periodically submerged for a certain period of time, and have repeated freezing and thawing. This mechanical weathering favored infiltration, which accelerated mineral dissolution. The high content of easily soluble carbonate of the sedimentary rocks is likely the major cause of intense chemical weathering. The dissolved elements within the infiltrated water interrupted the occurrence of clay and weathering minerals, and expend fractures by infiltrated water accelerated weathering process.

• Economic and Environmental Geology
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• v.24 no.4
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• pp.393-398
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• 1991

The Buyeo-Cheongyang area, in the south-western area of Gyeonggi massif, comprises Precambrian and Mesozoic metamorphic and sedimentary rocks. The original rock of metamorphic rocks was studied by geochemical examination and statistical analyses of the trace elements in the gneisses, schists, shale and granitic rocks. Average abundance of Cu,Cr,Pb,Ni,Co,Mn,Li and Zn elements from gneisses have similar to those from shale and schists. However the gneisses have higher Cr,Ni,Co,Mn,Li abundance than those from the granite. Abundance range and frequency distribution of the trace elements in the gneiss show a marked trend sedimentary origin, that is, standard deviation have far the higer than that of igneous origin. Also it is wide dispersion and irregularly distribution. For that reason, this gneiss is regard as sedimentary original rocks with schists.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.211-214
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• 1999

To acknowledge the differences in soil physical properties of cultivated land derived from major parent rocks in Yeong-nam areas, we investigated Riley's projection sphericity(one of the morphological properties) of sand and made up Soil Moisture Characteristics Curve(SMCC). The averages in Riley s projection sphericity range from 0.63 to 0.67 in soils derived from Sedimentary rocks than 0.56 to 0.61 in soils derived from igneous rocks. In case of soils derived from igneous rocks, the Riley's projection sphericity is lower as the particle size get to be smaller. The differences of SMCC were larger in the fine loamy soils than in coarse loamy soils. The moisture retention was higher in the soils derived from Sedimentary rocks than in the soils derived from Igneous rocks. After we transformed the water retention into dimensionless scale value by available water ratio, the SMCC was nearly unchangeable in the tested soils except for fine loamy soils derived from Sedimentary rock, but was not correlated with soil texture or parent rocks.