• 제목/요약/키워드: Triassic

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담양(潭陽)-진안(鎭安)사이에 분포(分布)하는 엽리상화강암류(葉理狀花崗岩類)에 대(對)한 지질시대(地質時代)와 성인(成因)에 관(關)한 연구(硏究) (Geochronology and Petrochemistry of Foliated Granites between Damyang and Jinan)

  • 김정빈;김용준
    • 자원환경지질
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    • 제23권2호
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    • pp.233-244
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    • 1990
  • Plutons of Damyang-Jinan area consist of gray feldspar granite gneiss, biotite granite gneiss, foliated granites, Namweon granites, gabbro, biotite granite and Ogangri granite in term of mineralogical, texture and field evidence. From Isotope data of study area, chronological order of the Plutons are the Pre-cambrian gray feldspar granite gneiss(Ar39-Ar40, hornblende, $1998.4{\pm}8.3Ma$), middle to late Triassic Daegang foliated granite(Rb/Sr, whole rock, $288{\pm}4Ma$), foliated hornblende biotite granodiorite(K/Ar, hornblende, $198.7{\pm}9.9Ma$), Sunchang foliated granodiorite(Rb/Sr, whole rock, $222{\pm}4Ma$), foliated two mica granite, Samori foliated granite and Namweon granite(Rb/Sr, whole rock, $211{\pm}3Ma$: K/Ar, hornblende, $203{\pm}10.2Ma$), middle Jurassic Gabbro(K/Ar, hornblende, $180.7{\pm}9MA$) and biotite granite, and Cretaceous Ogangri granite. According to variations diagrams of $Al_2O_3$ versus normative PI(100 An)/(Ab+An), Daegang foliated granite is plotted on tholeiitic series, and other foliated granites on calc alkaline rock series which are consider to be formed by magmatism at continental margin and island arc region. And alkalinity versus $SiO_2$ shows that Daegang folited granite and Samori foliated granite are correspond to alkaline region, foliated hornblende biotite granodiorite and Sunchang foliated granodiorite to calc alkaline region, and foliated two mica granite to both regions. According to ACF diagrams, Daegang and Samori foliated granites are plotted on S-type. Foliated hornblende biotite granodiorite and Sunchang foliated granodiorite on I-type, and foliated two mica granite on both type. Foliated granites are a series of differentiated products from cogenetic magma, and effected under ductile sheared zone. Characteristic foliation of foliated granites are considered to be generated by dextral strike slip faulting and ductile shearing.

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옥천지향사대(沃川地向斜帶) 동남대(東南帶)에서의 화성활동(火成活動)(I): 남원(南原)-거창(居昌)-상주(尙州) 지역(地域)을 중심(中心)으로 (The study on the Igneous Activity in the Southeastern Zone of the Ogcheon Geosynclinal Belt, Korea(I) with the Igneous Activity in Namweon-Geochang-Sangju Area)

  • 김용준;박영석;주승환;오민수
    • 자원환경지질
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    • 제22권4호
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    • pp.355-370
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    • 1989
  • Igneous rocks of study area consist of Pre-Cambrian orthogneiss, Devonian granite, Triassic foliated granites and Jurassic granites distributed along the southeast margin of Ogcheon Geosynclinal belt(SE-zone), and irregular shaped granitic stocks in the central part of the belt(C-zone). Anorthosite and gaabbro are also present in southern part of the SE-zone in the belt and intruded into gneiss complex of Ryongnam massif. Distribuition of foliated granites shows three linear arrangements which are composed of hornblende-biotite foliated granodiorite, porphyritic foliated granodiorite, biotite foliated granodiorite, leuco foliated granite and two mica foliated granite. Foliated granites generated by dextral strike slip movement at deep level. Jurassic granites composed of several rock facies are considered to be formed by differentiation of magma during Daebo Orogeny. A general trend of the chemical composition of these igneous rocks in study area suggests that most of them corresponding to calc-alkaline rock series was affected under orogeny and I-type granite except for two mica foliated granite. In chondrite normalised REE pattern of these igneous rocks, LREE shows more variable range and strong (-)Eu anomaly than HREE. Geochronological episodes of igneous activity from early Proterozoic to Cretaceous in SE-zone of Ogcheon Geosynclinal belt are two more Pre-Cambrian Orogeny, Devonian Orogeny(Variscan), Songrim Disturbance, Daebo Orogeny and Bulkuksa Disturbance.

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옥천대 북동부에 분포하는 하부 고생대층에 대한 고지자기 연구 (Paleomagnetic Study of the Lower Ordovician Formations in the North Eastern Okcheon Zone)

  • 민경덕;이윤수;황석연
    • 자원환경지질
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    • 제26권3호
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    • pp.395-401
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    • 1993
  • Lower Ordovician rock samples were collected from 23 sites located at the Okcheon non-metamorphic zone, near Taeback and Yeongweol areas, southern part of the Korean Peninsula. A characteristic magnetic component was obtained from four sites. This stable direction ($Dm=-19.4^{\circ}$, $Im=24.1^{\circ}$) which is carried by hematite of very high temperature $679^{\circ}C$), successfully pass both of reversal test and paleopole reliability test, and is regarded as a primary direction. The remagnetized components can be divided into three on the basis of their characteristic directions and magnetic minerals. The first which is carried by hematite, magnetite and pyrrhotite, is widely found at the whole sites. It shows syn- or post-tectonic remagnetization according to strongly negative fold test and distribution between Mesozoic and present field directions. The second, in situ, is distinguishable from the present field direction. After bedding correction, it is identical to Late Triassic to Early Jurassic direction. Its magnetic carrier is considered to be a single component hematite, which may be acquired by pre-tectonic CRM in the Okcheon orogenic zone. The third, which is carried by magnetite and hematite, is characterized by stable reversed direction. These minerals may be acquired by the thermal or chemical process in unknown period. Paleopole position is $169.2^{\circ}E$ in longitude and $59.9^{\circ}S$ in latitude, which indicates that the study area was located at $12.6^{\circ}S$ in paleo-latitude and belonged to northern end of the Gondwana in Early Ordovician.

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담양(潭陽)-진안(鎭安)사이에 분포(分布)하는 엽리상화강암류(葉理狀花崗岩類)에 대(對)한 암석화학적(岩石化學的) 연구(硏究) (Geochemical Study on Foliated Granites in the Damyang-Jinan area)

  • 김정빈;김용준;홍세선
    • 자원환경지질
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    • 제23권1호
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    • pp.87-104
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    • 1990
  • Foliated granites between Damyang and Jinan are subdivided into Daegang foliated granite, Foliated hornblende biotite granodiorite, Sunchang foliated granodiorite, Foliated two mica granite and Samori foliated granite by mineral and texture. From EPMA data of the foliated granites following results are achieved. Composition of plagioclase are correspond to andesine, oligoclase and albite in Foliated hornblende biotite granodiorite, Sunchang foliated granodiorite and other foliated granites, respectively. And amphiboles are calcic hornblende in Foliated hornblende biotite granodiorite, and riebeckite in Daegang foliated granite. In differentiation index(D. I.) and Larsen index(L. I.), Daegang foliated granite, Foliated two mica granite and Samori foliated granite which belong to granite are 83.12-95.54 and 25.86-29.05 and Foliated hornblende biotite granodiorite and Sunchang foliated granodiorite of diorite to granodiorite are 54.99-78.54(D. I.) and 6.48-21.01(L. I.). Harker and AMF diagrams plotted from foliated granites show that the granites are product of calc alkali rock series orignated from co-magma. Characteristic foliation of foliated granites fromed by ductile deformation at deep zone of dextral strike slip fault. Foliated granites are considered as a series of differentiated product of Triassic Igneous activity of Songrim disturbance. According to REE, (La/Lu) and Eu/Sm, Foliated hornblende biotite granodiorite and Sunchang foliated granodiorite are correspond to granodiorite, and other foliated granites are monzo-and syeno-granite. Foliated granites having 0.20-0.01 of Em/Sm ratio are plutons emplaced by the tectonic setting in continents and continental margin.

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Comparative Study on the Runoff Process of Granite Drainage Basins in Korea and Mongolia

  • Tanaka, Yukiya;Matsukura, Yukinori
    • 한국제4기학회지
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    • 제17권2호
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    • pp.79-84
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    • 2003
  • This study revealed the differences in runoff processes of granite drainage basins in Korea and Mongolia by hydrological measurements in the field. The experimental drainage basins are chosen in Korea (K-basin) and Mongolia (M-basin). Occurrence of intermittent flow in K-basin possibly implies that very quick discharge dominates. The very high runoff coefficient implies that most of effective rainfall quickly discharge by throughflow or pipeflow. The Hortonian overlandflow is thought to almost not occur because of high infiltration capacity originated by coarse grain sized soils of K- basin. Very little baseflow and high runoff coefficient also suggest that rainfall almost does not infiltrate into bedrocks in K-basin. Flood runoff coefficient in M-basin shows less than 1 %. This means that most of rainfall infiltrates or evaporates in M-basin. Runoff characteristics of constant and gradually increasing discharge imply that most of rainfall infiltrates into joint planes of bedrock and flow out from spring very slowly. The hydrograph peaks are sharp and their recession limbs steep. Very short time flood with less than 1-hour lag time in M-basin means that overland flow occurs only associating with rainfall intensity of more than 10 mm/hr. When peak lag time shows less than 1 hour for the size of drainage area of 1 to 10 km2, Hortonian overland flow causes peak discharge (Jones, 1997). The results of electric conductivity suggest that residence time in soils or weathered mantles of M-basin is longer than that of K-basin. Qucik discharge caused by throughflow and pipeflow occurs dominantly in K-basin, whereas baseflow more dominantly occur than quick discharge in M-basin. Quick discharge caused by Hortonian overlandflow only associating with rainfall intensity of more than 10 mm/hr in M-basin.

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한반도 서남부에 분포하는 중성-염기성 심성암류에 대한 암석학적 연구 (Petrological Study on the Intermediate-basic Plutonic Rocks in the Southwestern Part of the Korean Peninsula)

  • 김용준;박재봉;박병규
    • 한국지구과학회지
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    • 제27권5호
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    • pp.528-538
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    • 2006
  • 이 연구의 목적은 한반도 서남부에 분포하는 중성-염기성 심성암류의 지화학적 특성과 성인을 밝히는데 있다. 이들 중성-염기성암류는 주로 선캠브리아기의 회장암-반려암, 트라이아스기의 각섬석반려암(지리산 지역), 쥬라기의 섬록암-섬장암(지리산 지역과 북부 지역) 그리고 백악기 반려암-섬록암(남부 지역)으로 구성되어 있다. 암괴형의 회장암은 많은 관입체로 구성되어 있으며 반려암-노라이트-트록토라이트와 우백질 반려암으로 이루어진 반려암질암에 의해 관입되어 있다. 주 성분-미량 성분의 변화도, AMF 삼각도와 Pl-Px-Ol 삼각도에서, 우리는 한반도 서남부에 분포하는 중성-염기성암류가 Daly의 값과 유사한 경향을 보이며 칼크-알카리질암류에 속함을 보여준다. REE (La/Yb)cw와 Eu/Sm 값에 따르면 이들 암류는 경희토류가 중희토류보다 부화되어 있으며, 이는 대륙 연변부의 지구조에서 정치한 화성암류의 특징이다.

Geochrononlogy and thermal history of the Chuncheon granite in the Gyeonggi massif, South Korea

  • Jin, Myung-Shik;Shin, Seong-Cheon;Kim, Seong-Jae;Choo, Seung-Hwan
    • 암석학회지
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    • 제2권2호
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    • pp.122-129
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    • 1993
  • We report Rb-Sr whole rock, K-Ar and fission track mineral ages for the Chuncheon granite in the Precambrian Gyeonggi massif. The Rb-Sr whole rock define an age of $196{\pm}9$ Ma with an initial ratio of $0.7159{\pm}0.0006$, suggesting that the granitic magma might have been generated from crustal sources (S-type), or probably mixed mantle and crustal materials, and emplaced into the massif in the late Triassic or the early Jurassic. K-Ar mineral ages of hornblende, muscovite and biotite are ~210 Ma, ~180 Ma and 166-170 Ma respectively, and fission track zircon and apatite ages are 65-70 Ma, ~35 Ma respectively. These ages indicate that the granitic magma might have been emplaced at about 7 to 9 km from the paleosurface, and rapidly cooled down up to $300^{\circ}C$ until middle Jurassic (~170 Ma) with a rate of about $10^{\circ}C$/Ma, due to thermal difference between the magma and the wall rock. During middle Jurassic to late Cretaceous (about 170-70 Ma), the granite pluton is assumed to have uplifted to 4 to 6 km level under the paleosurface with a rate of 30 m/Ma and slowly cooled down with a rate of about $1^{\circ}C$/Ma owing to relatively slow denudation of the massif. In late Cretaceous to the present, the pluton might have more rapidly uplifted to the present level with a rate of 85 m/Ma and rapidly cooled down with a rate of about $3^{\circ}C$/Ma compared to those of middle Jurassic to late Cretaceous time because of extensive igneous activities accompanied by tectonism in the Gyeonggi massif.

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충주문경간(忠州聞慶間)의 옥천계(沃川系)의 층서(層序)와 구조(構造) (Stratigraphy and Tectonics of Okcheon System in the Area between Chungju and Munkyeong)

  • 김옥준
    • 자원환경지질
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    • 제1권1호
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    • pp.35-46
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    • 1968
  • Some of geologists in Korea recently postlated that Okchon system previously known to be precambrian age was the metamorphosed sediments of post-Chosen (Ordovician and pre-Kyeongsang (late Jurassic to Cretaceous) periods, or even definitely of Triassic period simply on the basis of the fact that Okcheon system overlies the Great Limestone series of Chosen system of Camber-ordovician age, and of other few assumptions of minor importance. As a result of such correlation, thick series of metasediments and Okcheon system of unknown age were established in this particular region and vaguely correlated to Paleozoic and Mesozoic sediments. Recent study done by the author reveled that: 1) only the upper Okcheon bed of S. Nakamura was true Okcheon system, and the middle and lower Okcheon beds were excluded, because they were correlated to Cambrian and Permian sediments resfectively, 2) Sangnaeri, Seochangri, and rengam formations of unknown age, and Baekhwasan, Jobong, and Ihwaryeong formations of Okcheon system of also unknown age were the metamorphosed Yangdeok system of Cambrian age, all of these formations were differentiated by the previous workers and were equivalent to the middle Okcheon system of S. Nakamure, and. 3) These metamorphosed Yangdeok system overlaid apparently the Great Limestone series in forms of overthrust and klippe which were produced by the orogeny took place during post-Daedong and pre-Kyeongsang period (probably middle to the Jurassic). The Sobaeksan Range, folded mountain Chains was also formed by this orogeny. Thus, Okcheon system newly defined by the author is precambrain age and consists in ascending order of Kemyenogsan, Hyangsan dolomite, and Daehangsan quartzite formation which were previously classified into metasediments of unknown age, and Munjuri, and Hwangkanri, formations which were differentiated into Okcheon system unknown age by the previous workers, but are of reversed sequence. Myeongori and Bukrori formations of Okcheon System are regard by the author as part of Hwangkanri formation. Few other assumption of minor important taken by the previous workers as their positive evidences are carefully explained that they were misinterpreted.

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옥천대(沃川帶)에서의 화성활동(火成活動) -특(特)히 옥천대동북부(沃川帶東北部)에서의 화성활동(火成活動)- (Igneous Activity in Ogcheon Geosynclinal Zone, Korea -with Special Reference to the Igneous Activity in its Northeastern Part-)

  • 이대성;김용준
    • 자원환경지질
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    • 제18권1호
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    • pp.23-39
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    • 1985
  • The northeastern part of Ogcheon zone which consisted mainly of Cambro-Ordovician arenaceous, argillaceous and calcareous formations and Carboni-Triassic arenaceous and argillaceous formations is delineated as the eastern mass of a thrust fault along Choongju-Moongyong-Cheongsan in the middle of the zone. The present study proposes a geotectonic line, Imgye-Samchog fault(see, figure 1) which divides the northeastern part into two blocks, Hambacksan block in the west and East coast block in the east. The igneous rocks in the Hambacksan block ranging from granite to gabbro are distributed in a symmetrical zones parallel to general direction of Ogcheon zone as follows (Fig. 2 and Table 2). Southeast igneous rock zone: it aligns Jurassic granites in its south and Precambrian leucocratic granites in its north. Central igneous rock zone: it aligns Cretaceous granites in its south and Jurassic granites, and some of diorite and gabbro in its north. Northwest igneous rock zone: aligns Jurassic granites in its south and huge batholithic granodiorite in its north. The distribution of the igneous rocks in the East coast block shows an entirely different features from those of Hanbacksan block. In the southern part of the block they assemble in a narrow area ranging in age from Early Proterozoic, through Middle to Late Proterozoic, Devonian, Jurassic, Cretaceous to Tertiary, whereas, the igneous rocks in the northern part of the block gathered to a restricted area, in ages of Middle Proterozoic and Cretaceous. The assemblage of the igneous rocks in the studied area shows a compositionally restricted, mixed S-type and I-type granites, $^{87}Sr/^{86}Sr$ > 0.706, rare volcanics and shortening with upright folding. These lithologic and structural features suggest that the igneous activity in this part related intimately to Hercynotype Orogeny of Pitcher(1979). Chronological episodes of igneous activity from Early Proterozoic to Early Tertiary in the northeastern part are figured.

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경기 편마암복합체 변성암의 CHIME 절대연대측정 (CHIME Ages of Monazites from Metamorphic Rocks from the Precambrian Gyeonggi Gneiss Complex in the Shiheung and Seosan Group of the Gyeonggi Massif, South Korea)

  • 김규한;령목화박;이종익;장현경
    • 자원환경지질
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    • 제41권2호
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    • pp.173-181
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    • 2008
  • 한반도 경기편마암 육괴내 서산층군과 시흥층군의 대표적인 변성암 시료에 대하여 CHIME 절대연령 측정을 실시하였다. 경기편마암복합체 변성암중의 모나자이트 CHIME연령은 234${\sim}$257 Ma로 페름기-트라이아스기 중기에 속하고 있다. 이 연령은 경기육괴내 흥성지역의 변성시기(231 Ma, Kim et al., 2006)와 오대산 지역의 변성시기(245${\sim}$248 Ma, Oh et al., 2006b)와도 조화적이며 남중국지괴와 북중국 지괴의 충돌에 의한 송림 변동으로 일어난 지각변동과 수반된 변성작용의 시대로 해석된다. 한반도의 경기육괴 서산층군과 시흥층군의 변성암의 변성연대는 다비-수루 충돌대의 변성 연대(220${\sim}$242 Ma, Yang et al., 2003; Liu et al., 2003, 2004) 보다 오래되며 이는 남중국과 북중국 지괴의 충돌이 중국대륙에서 보다 한반도 지역에서 선행되었을 가능성을 시사하고 있다.