• Title/Summary/Keyword: tectonic environment

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A study on the effect factor of architectural material expression (재료의 물성 표현에 영향을 주는 요인 연구)

  • Kim, So-Hee
    • Korean Institute of Interior Design Journal
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    • v.15 no.6 s.59
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    • pp.60-67
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    • 2006
  • In modem days when architectural materials have grave impacts on overall design expression, materials for architecture, especially finishing materials have become the most essential elements for the design expression, as architectural space and form have been. When it comes to the architectural materials, they can be conceived by visual and tactile sensory system and perceptional system which based on memory and experience. This study confirms how materials bring into effect on architecture in the sense of its design. The main subject of this analysis is expression method of architectural finishing materials. Also, this study finds out the relationship between finishing materials and the images of materials by analyzing the effect factor of architectural material expression with the perspectives of materials, formal and environments and by examining roles of the architectural materials in design. The material factor, in the expression of materiality, is how to make tectonic space and to vary the surface of building as finishing material design. The formal factor is related to set up the new direction in the architectural form and to create the dynamic and informal space. And the social and cultural environment as the effect factor gives new situation and context to architectural material expression. This principle enables us to use architectural materials as one of the important elements which express the whole characteristics of the area.

Time-series Analysis of Geodetic Reference Frame Aligned to International Terrestrial Reference Frame

  • Bae, Tae-Suk;Hong, Chang-Ki;Lee, Jisun;Altamimi, Zuheir;Sillard, Patrick;Boucher, Claude
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.39 no.5
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    • pp.313-319
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    • 2021
  • The national geodetic reference frame of Korea was adopted in 2003, which is referenced to ITRF (International Terrestrial Reference Frame) 2000 at the epoch of January 1, 2002. For precise positioning based on the satellites, it should be thoroughly maintained to the newest global reference frame. Other than plate tectonic motion, there are significant events or changes such as earthquakes, antenna replacement, PSD (Post-Seismic Deformation), seasonal variation etc. We processed three years of GNSS (Global Navigation Satellite System) data(60 NGII CORS stations, 51 IGS core stations) to produce daily solutions minimally constrained to ITRF. From the time series of daily solutions, the sites with unexpected discontinuity were identified to set up an event(mostly antenna replacement). The combined solution with minimum constraints was estimated along with the velocity, the offsets, and the periodic signals. The residuals show that the surrounding environment also affects the time series to a certain degree, thus it should be improved eventually. The transformation parameters to ITRF2014 were calculated with stability and consistency, which means the national geodetic reference frame is properly aligned to the global reference frame.

On the isostasy and effective elastic thicness of the lithosphere in southern prt of the Korean Peninsula (한반도 남부 지각평형과 암석권의 유효탄성두께)

  • Choi, Kwang-Sun;Kim, Jeong-Hee;Shin, Young-Hong
    • Journal of the Korean Geophysical Society
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    • v.5 no.4
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    • pp.293-303
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    • 2002
  • Applying elastic plate model, we estimated elastic thickness and rigidity of the lithosphere in southern part of the Korean Peninsula($332km{\times}332km$ area of which center is $36.5^{\circ}N$ in latitude and $127.5^{\circ}E$ in longitude) by analysing terrain data and gravity data measured up to 2002. We tried to exclude the East Sea in choosing the study area because it has different tectonic environment. The mean Moho depth was estimated to be 30 km by power spectrum analysis of gravity data in the study area, Assuming one layer crust and applying elastic plate model, the loads with wavelengths of greater than 300 km are locally compensated, loads with wavelengths in the range 80-300km are partially supported by the strength of the lithosphere, and loads with wavelengths of less than 80km are almost completely supported by lithospheric strength. Assuming crustal model and rigidity, we calculated predicted coherence and compared it with observed coherence. As a result, we wert able to estimate the effective elastic thickness to be of 15 km(corresponding flexural rigidity is $3.0{\times}10^{22}Nm$). This indicates that the crust of the study area is relatively weaker than other old and stable continental regions but is similar to continental margins or oceanic area. The low rigidity could be explained by many tectonic and thermal activities such as orogenic activities, magmatic intrusions, volcanic activities, foldings, faultings, etc.

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Petrogenesis and Metamorphism of Charnockite of Eastern Jirisan Area (지리산 동부 지역에 분포하는 차노카이트의 변성작용과 성인에 관한 연구)

  • 김동연;송용선;박계헌
    • The Journal of the Petrological Society of Korea
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    • v.11 no.3_4
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    • pp.138-156
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    • 2002
  • Precambrian metamorphic rocks of southwest Sobaeksan massif consist of mainly granitic gneiss, porphyroblastic gneiss and quartzofeldspathic gneiss. The orthopyroxene-bearing rocks(charnockites) are found in the west of Hadong-Sancheong anorthosite complex. The charnockites are 3km wide, 12km long and divided into massive and foliated types based on their texture. The compositions of charnockites are comparable to granodiorite to adamellite and subalkaline. Variations in major and trace elemental abundances show typical magmatic differentiation trends. The geochemical data plotted on tectonic discrimination diagrams reveal that these charnockites were formed in the active tectonic environment. The massive and folidated charnockites are mainly composed of plagioclase, orthopyroxene, microcline, quartz and disseminated garnet. Camels generally show characteristic zonal textures with decreasing $X_{alm}$(0.74~0.83), $X_{Py}$ (0.07~0.12) and $X_{Mg}$ (0.12~0.08) and increasing $X_{grs}$(0.03~0.15) from core to rim. Metamorphic temperature and pressure of the charnockites estimated from orthopyroxene-garnet-plagioclase-quartz assemblages show wide range of variation of $600~900^{\circ}C$ and 2.5~7.5 kbar respectively. The results of P-T estimates indicate an anticlockwise P-T evolution path.

Cyclic Igneous Activities During the Late Paleozoic to Early Cenozoic Period Over the Korean Peninsula (고생대말-신생대초 기간에 일어난 한반도의 주기적 화성활동)

  • Park, Kye-Hun
    • The Journal of the Petrological Society of Korea
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    • v.21 no.2
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    • pp.193-202
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    • 2012
  • There were three cycles of igneous activities from the late Paleozoic to early Cenozoic; Permian to Triassic, Jurassic, and Cretaceous to Paleogene. After the beginning of each igneous activity cycle, igneous activity became more frequent until its climax. It is noteworthy that A-type magmatisms are reported from near the ends of the all three igneous activity cycles. In addition, adakitic magmatisms occurred at the beginning of both the Permian-Triassic and the Cretaceous-Paleogene cycles. Most of the igneous activities during the late Paleozoic to early Cenozoic period were subduction-related. Therefore, transitions among beginning, proceeding, and closing of the igneous activity cycles would be intimately related with changes in directions of plate movements. In this context, I suggest following hypotheses. The closing of the Permian-Triassic igneous cycle was possibly a consequence of radical adjustment of plate motion occurred due to continental collision between north and south China blocks. Considering that no appreciable tectonic activities were recognized from the east Asian continent at the closing of the Jurassic igneous cycle, it seems that one of the strong events related with Gondwanaland-breakup and subsequent birth of the new oceans, which might cause sudden adjustments of plate motions. The closing of the Cretaceous-Paleogene igneous cycle seems to be caused as a consequence of the collision between India and Asia continents. Meanwhile, adakitic igneous bodies emplaced at the beginnings of the Permian-Triassic and Cretaceous-Paleogene cycles could be products of slab-melting during the early stages of the subduction.

Petrological, Geochemical and Geochronological Studies of Precambrian Basement in Northeast Asia Region: 2. Zircon Ages of Some Metamorphic Rocks from Gyeonggi Massif (동북아시아지역 선캠브리아 지괴에 대한 암석학, 지구화학 및 지구연대학적 연구: 2. 경기육괴 일부 변성암의 저어콘 연대)

  • ;;Cao Lin;Jin Wei;Zhang Xingzhou
    • The Journal of the Petrological Society of Korea
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    • v.10 no.2
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    • pp.95-105
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    • 2001
  • U-Pb age determination was performed on the zircon fractions separated from the metamorphic rocks of three locations of the Gyeonggi Massif. The ages obtained from the upper and lower intersections between concordia curve and discordia lines made of the zircon fractions separated from the rocks of each locality we: $2168\pm$24 Ma and $1227\pm$40 Ma for the Yongduri Gneiss Complex, $1955\pm$22 Ma and $493\pm$32 Ma for the Euiam Group, and $3712\pm$244 Ma and $1613\pm$51 Ma for the Yongmunsan Group (2$\sigma$ errors). The upper intercept ages from the Yongduri Gneiss Complex and the Euiam Group of Gyeonggi massif are very similar to those obtained from the granitic gneisses and the porphyroblastic gneisses of Yeongnam massif respectively. Such similarities suggest that Gyeonggi and Yeongnam massifs might situate under the similar tectonic and geographic environment during ca. 2.2-1.9 Ga. The upper intercept age of Youngmunsan Formation (3.7 Ga) shows large error, because most of the zircon fractions are plotted very close to the lower intersection. It is necessary to investigate further to confirm this age. However, It may suggest the possibility of occurrence of the oldest crust of the northeast Asia similar to the one reported recently from the northeast China. The lower intercept age of the Yongmunsan Group is interpreted to indicate strong metamorphism. Such age postdates the 1.85-1.7 Ga metamorphism and igneous activities occurred in the Yeongnam massif, which might record the late Paleoproterozoic tectonic activities simultaneously occurred in both massifs.

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Geochemical Study of the Cretaceous Granitic Rocks in Yeosu Area (여수 지역에 분포하는 백악기 화강암류에 대한 지화학적 연구)

  • Wee, Soo-Meen;Kim, Eun-Hyo
    • Journal of the Korean earth science society
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    • v.30 no.3
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    • pp.267-281
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    • 2009
  • Cretaceous intrusive and extrusive rocks are widely distributed in the southern part of the Korean peninsula, possibly the result of intensive magmatism which occurred in response to subduction of the Pacific plate beneath the northeastern part of the Eurasian plate. Geochemical and petrological study on the Cretaceous granitic rocks of the Yeosu area were carried out in order to constrain the petrogenesis of the granitic rocks and to establish the paleotectonic environment of the southwestern part of the Korean peninsula. Igneous rocks of the Yeosu area consist of diorite, hornblende biotite pite and micrographic granite. Chondrite normalized REE patterns show generally enriched in LREE ($(La/Lu)^{cN}$=4.2-13.3). Diorites show flat to slight negative Eu anomalies while micrographic granites have strong negative Eu anomalies. The ${\Sigma}REE$ of the granites are 76.2-235 ppm, which corresponds to the range of the continental margin granite. Whole rock chemical data of the granitic rocks from the Yeosu area indicate that the rocks have characteristics of calc-alkaline series in the subalkaline field. On the A/NK vs. A/CNK and tectonic discrimination diagrams, parental magma type of the granites corresponds to I-type and volcanic arc granite (VAG). Interpretations of the chemical characteristics of the granitic rocks favor their emplacement in a compressional tectonic regime at continental margin during the subduction of Pacific plate.

The Physical Region of China Divided by the Characteristics of Drainage Patterns. (하계망패턴의 특색으로 구분한 중국의 자연지역)

  • Hwang, Sang-Ill
    • Journal of the Korean association of regional geographers
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    • v.2 no.1
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    • pp.151-164
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    • 1996
  • The regional division by the characteristics of the drainage patterns is important to understand its physical environment comprehensively, because the drainage network develops in reflecting characteristics of geological, geographical and climatical features in the drainage basin keenly. This study is the attempt to divide physical region in China whose drainage pattern is diverse. Chinese drainage basin is mainly divided into the interior drainage basin and the peripheral drainage basin. The interior drainage basin is divided into (1)the deranged pattern and (2)the centripetal pattern. The peripheral drainage basin is divided into (1)the dendritic pattern, (2)the parallel pattern, (3)the radial pattern and (4)the anastomatic pattern. Drainage patterns of the interior drainage basin are formed by affecting geographical features and climatic conditions mainly. In the peripheral drainage basin, drainage patterns are formed by other factors: the parallel pattern is connected with geological structure lineament by tectonic movement, the radial pattern with changes of the river channel resulted from the Yellow River's overflow, the anastomotic pattern with human's activities. The distributional features of the physical region in China are as follows: The deranged pattern appears in Zangbai Plateau, the centripetal pattern does in arid basin of the northwest China. the parallel pattern does in Hengduan mountains affected strongly by tectonic movement between Yangtze paraplatform and Indian Plate, does in the upper stream of Yangtze River and Ganges River in the south of Qinghai-Xizang Plateau, the radial pattern in Huaihe Haihe River drainage basin appearing in the alluvial fan region of Yellow River's downstream and the anastomotic pattern does in the delta of Yangtze River, in the northern coastal plain of the Jiangsu-Province and in the delta of Zhujiang River. Except these areas in the peripheral drainage basin, the dendritic pattern is usually found in the other areas.

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Petrotectonic Setting and Petrogenesis of Cretaceous Igneous Rocks in the Cheolwon Basin, Korea (철원분지 백악기 화성암류의 암석조구조적 위치와 암석성인)

  • Hwang, Sang-Koo;Kim, Se-Hyeon;Hwang, Jae-Ha;Kee, Won-Seo
    • The Journal of the Petrological Society of Korea
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    • v.19 no.1
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    • pp.67-87
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    • 2010
  • This article deal with petrotectonic setting and petrogenesis from petrography and chemical analyses of the Cretaceous volcanic and intrusive rocks in the Cheolwon basin. The volcanic rocks are composed of basalts in Gungpyeong Formation, Geumhaksan Andesite, and rhyolitic rocks (Dongmakgol Tuff, Rhyolite and Jijangbong Tuff), and intrusive rocks, Bojangsan Andesite, granite porphyry and dikes. According to petrochemistry, these rocks represent medium-K to high-K basalt, andesite and rhyolite series that belong to calc-alkaline series, and generally show linear compositional variations of major and trace elements with increase in $SiO_2$ contents, on many Harker diagrams. The incompatible and rare earth elements are characterized by high enrichments than MORB, and gradually high LREE/HREE fractionation and sharp Eu negative anomaly with late strata, on spider diagram and REE pattern. Some trace elements exhibit a continental arc of various volcanic arcs or orogenic suites among destructive plate margins on tectonic discriminant diagrams. These petrochemical data suggest that the basalts may have originated from basaltic calc-alkaline magma of continental arc that produced from a partial melt of upper mantle by supplying some aqueous fluids from a oceanic crust slab under the subduction environment. The andesites and rhyolites may have been evolved from the basaltic magma with fractional crystallization with contamination of some crustal materials. Each volcanic rock may have been respectively erupted from the chamber that differentiated magmas rose sequentially into shallower levels equivalenced at their densities.

Banded Iron Formations in Congo: A Review

  • Yarse Brodivier Mavoungou;Anthony Temidayo Bolarinwa;Noel Watha-Ndoudy;Georges Muhindo Kasay
    • Economic and Environmental Geology
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    • v.56 no.6
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    • pp.745-764
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    • 2023
  • In the Republic of Congo, Banded iron formations (BIFs) occur in two areas: the Chaillu Massif and the Ivindo Basement Complex, which are segments of the Archean Congo craton outcropping in the northwestern and southwestern parts of the country. They show interesting potential with significant mineral resources reaching 2 Bt and grades up to 60% Fe. BIFs consist mostly of oxide-rich facies (hematite/magnetite), but carbonate-rich facies are also highlighted. They are found across the country within the similar geological sequences composed of amphibolites, gneisses and greenschists. The Post-Archean Australian Shale (PAAS)-normalized patterns of BIFs show enrichment in elements such as SiO2, Fe2O3, CaO, P2O5, Cr, Cu, Zn, Nb, Hf, U and depletion in TiO2, Al2O3, MgO, Na2O, K2O, Sc, Th, Ba, Zr, Rb, Ni, V. REE diagrams show slight light REEs (rare earth elements; LREEs) compared to heavy REEs (HREEs), and positive La and Eu anomalies. The lithological associations, as well as the very high (Eu/Eu*)SN ratios> 1.8 shown by the BIFs, suggest that they are related to Algoma-type BIFs. The positive correlations between Zr and TiO2, Al2O3, Hf suggest that the contamination comes mainly from felsic rocks, while the absence of correlations between MgO and Cr, Ni argues for negligeable contributions from mafic sources. Pr/Pr* vs. Ce/Ce* diagram indicates that the Congolese BIFs were formed in basins with redox heterogeneity, which varies from suboxic to anoxic and from oxic to anoxic conditions. They were formed through hydrothermal vents in the seawater, with relatively low proportions of detrital inputs derived from igneous sources through continental weathering. Some Congolese BIFs show high contents in Cr, Ni and Cu, which suggest that iron (Fe) and silicon (Si) have been leached through hydrothermal processes associated with submarine volcanism. We discussed their tectonic setting and depositional environment and proposed that they were deposited in extensional back-arc basins, which also recorded hydrothermal vent fluids.