• Title/Summary/Keyword: Foliated granite

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Geochronology and Petrochemistry of Foliated Granites between Damyang and Jinan (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))

  • Kim, Cheong Bin;Kim, Yong Jun
    • Economic and Environmental Geology
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    • v.23 no.2
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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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Geochemical Study on Foliated Granites in the Damyang-Jinan area (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))

  • Kim, Cheong-Bin;Kim, Yong-Jun;Hong, Sei-Sun
    • Economic and Environmental Geology
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    • v.23 no.1
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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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Petrochemistry of Granitoids in the Younggwang-Kimje area, Korea (영광-김제 지역 화강암류의 암석화학적 연구)

  • Park, Young-Seog;Kim, Jong-Kyun;Kim, Jin
    • Economic and Environmental Geology
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    • v.34 no.1
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    • pp.55-70
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    • 2001
  • Granitoids in the Younggwang-Kimje area can be divided into two types of granite. One is foliated granite (Cheongup and Kochang foliated granites) developed along the NE-SW direction kwangju fault system and the other is undeformed granite (Kimje and Younggwang granites) developed in the western part of the area. $SiO_2$ content of study area, Younggwang granite is 62.8-74.0%, Kochang foliated granite is 64.5-74.4%, Cheongup foliated granite is 64.5-70.2%, Kimje granite is 63.4-72.0%. The result indicated that these granitoids belong to the intermediate and acidic rock. In Harker's diagram, as $SiO_2$ increases, $Al_2O_3$, $Fe_2O_3$, MgO, CaO, $TiO_2$> $P_2O_{5}$s and MnO decrease, but $K_2O$ increases. In AFM diagram, Younggwang granite, Kochang foliated granite, Cheongup foliated granite and Kimje granite belong to calk-alkaline rock series. And in triangular diagrams of normative Qz-Or-Pl and An-Ab-Or, they are located in granodiorite and granite region. On the co-variation diagrams of trace elements with silica, Ba, Co, Li, Nb, An, Rb elements show increasing patterns. The diagrams of ACF and $Na_2O$ vs. $K_2O$ ratios indicate that granitoids of the study area belong to I-type.

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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 (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)

  • Kim, Yong Jun;Park, Yong Seog;Choo, Seung Hwan;Oh, Mihn Soo
    • Economic and Environmental Geology
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    • v.22 no.4
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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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The Study on Geochronology and Petrogenesis of Foliated Granites in the Honam Shear Zone, South Korea (호남 전단대내에 분포하는 엽리상화강암류의 지질시대와 생성과정에 관한 연구)

  • Kim, Yong-Jun;Park, Young-Seog;Kang, Sang-Won
    • Economic and Environmental Geology
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    • v.27 no.3
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    • pp.247-261
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    • 1994
  • Honam Shear Zone is a mylonite zone approximately parallel to the NE-SW trend located southern part of Korea peninsula. Geologic ages and petrogenesis of foliated granites in this zone are as follows: Igneous rocks of this zone are composed of granite gneiss, Paleozoic granites, Songrim granites, Jurassic granites and Cretaceous granites. Foliated granites show deformed phase of Paleozoic and Songrim granites during Daebo Orogeny. And isotopic ages obtained from foliated granites are early Permian to late Triassic period (276~200 Ma). Most of foliated granite masses are igneous complex consisting of a series of differential product of cogenetic magma. The individual rock mass of foliated granites plotted on Harker diagram shows mostly similar trend of calc-alkali series. REE diagram indicates that LREE amount of foliated granites are more enriched than HREE and negative Eu anomalies of them are weaker than those of the other granites. From these data, we suggest the rocks are generated from continental margin under syntectonic environment. Original magma type of foliated granites correspond to I-type, syn-collision type and Hercyano type. In compressive stress field between Ogcheon folded belt and Youngnam massif, foliated granites had formed due to mylonitic deformation. Those facts indicate that magma of foliated granites would had been generated by melting in lower crust or contamination in upper mantle.

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Nature of contact between the Ogcheon belt and Yeongnam massif and the Pb-Pb age of granitic gneiss in Cheondong-ri, Danyang (단양 천동리 지역 옥천대/영남육괴의접촌관계와 소위 화강암질 편마암의 Pb-Pb 연대)

  • 권성택;이진한;박계헌;전은영
    • The Journal of the Petrological Society of Korea
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    • v.4 no.2
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    • pp.144-152
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    • 1995
  • The Jangsan Quartzite of the Joseon Supergroup and the foliated granite (so-called granitlc gneiss of presumed Precambrian age) of the Yeongnam massif are in direct contact at Cheondong-ri area, 6 km @SE of Danyang. sllthough it has been thought traditionally that the Jangsan Quartzite overlies unconformably the f&ted granite, it is difficult to interpret the contact as an unconformity smce the basal conglomerate in- the lower part of the Jangsan Quartzite does not have any clast of the foliated granite, Rather, recent structural studies of this area indlcate that the contact is a ductile shear zone. However, the sense and age of the shear movement are still problematic. Our mesoscopic and microscopic studies of &tre Cheondong-11 semi-brittle shear zone involving foliated cataclasite and phyllonite, which is a pa& of the Ogdong fault, indlcate a top-to-the northeast shearing, i.e., dextral strike slip. We also performed Pb-Pb dating for the age-unknown foliated granite, since the age of deformed granite ccarr emtrain the maximum age of deformation. The whole rock and feldspar Pb isotape data for the foliated granite and a micaceous xenolith define an isoc chron age of $2.16{\pm}0.15$ Ga ($2{\sigma}$;MSWD=4.4) which is interpreted as the emplacement age of the granite. This early Proterozoic age agrees with those of Precambrian igneous activity In the Yeongnam massif reported previously. The obtaiPrfid gge confirms the traditional idea about the age of the foliated granite and indicates that other methd(s) should be employed to constrain the age of the shear movement.

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Petrochemistry and Sr ${\cdot}$ Nd Isotopic Composition of foliated Granite in the Jeoniu Area, Korea (전주지역 엽리상화강암의 암석화학 및 Sr ${\cdot}$ Nd 동위원소 조성)

  • Shin, In-Hyun;Park, Cheon-Young;Jeong, Youn-Joong
    • Journal of the Korean earth science society
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    • v.22 no.1
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    • pp.1-9
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    • 2001
  • Composition of the major and trace elements, Rb-Sr isochron age Sr-Nd isotope composition were determined for foliated in the Jeonju area, in the middle part of the Ogcheon Fold Bet, Korea. The geochemical characteristics of the Jeonju foliated granite indicate that the granite had been crystallized from a calc-alkaline series, and formed in a volcanic are environment. The isotopic compositions of the Jeonju foliated granite give Rb-Sr whole rock errorchron age of 168.2${\pm}$8 Ma(2${\sigma}$), corresponding to the middle Jurassic period, with the Sr initial ratio of 0.71354${\pm}$0.00031. $^{143}$Nd/$^{144}$Nd ratios, ${\varepsilon}$Nd and ${\varepsilon}$Sr values range from 0.511477 to 0.511744, -15.4${\sim}$-21.2, and +108.8${\sim}$+l42.6, respectively. Model ages were caculated to be 1.82${\sim}$2.89Ga. The isotopic data of Jeonju foliated granite indicate that the source material may have been derived from partial melting of continental crust materials.

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CHIME Monazite Ages of Jurassic Foliated Granites in the Vicinity of the Gangjin Area, Korea (강진 인근 쥬라기 엽리상 화강암류의 CHIME 모나자이트 연대측정)

  • Cho, Deung-Lyong;Kee, Weon-Seo;Suzuki, Kazuhiro
    • The Journal of the Petrological Society of Korea
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    • v.16 no.3
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    • pp.101-115
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    • 2007
  • The CHIME (chemical Th-U-total Pb isochron method) dating on monazite was carried out for two foliated granites from a dextral ductile shear zone in the vicinity of Gangjin area, which is considered to be a southern extension of Sunchang shear zone. The result gives emplacement age of the medium-grained biotite granite and the coarse-grained biotite granite as $183.6{\pm}2.2Ma$(MSWD=0.21) and $171.7{\pm}4.0Ma$(MSWD=0.57), respectively. Microtextures of quartz and feldspar observed in the foliated granite are almost identical with those reported in Jurassic (ca 180 Ma) foliated granites from the Imsil-Namwon area of the Sunchang shear zone, and they constraint that the ductile deformation took place at temperature condition of $300{\sim}550^{\circ}C$. Assuming cooling curves of the foliated granites in this study are similar with those of Jurassic foliated granites from Imsil-Namwon area, dextral ductile shear in the Gangjin area would take place between 172 Ma and 150 Ma, about 10 Ma later than the previous estimation based on CHIME monazite ages.

Petrochemical Study on Igneous Rocks in the Hamyang area, Kyongnam, Korea (경남(慶南) 함양지역(咸陽地域)에 분포(分布)하는 화성암류(化成岩類)에 대(對)한 암석화학적(巖石化學的) 연구(硏究))

  • Park, Jay-Bong;Kim, Yong-Jun;Kim, Cheong-Bin
    • Economic and Environmental Geology
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    • v.23 no.1
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    • pp.105-123
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    • 1990
  • Igneolls rocks of the Hamyang area consist of Hamyang foliated granites and hornblende diorite. Hamyang foliated granites are classified into four rock types in terms of mineral composition and texture. The four rock types are foliated hornblende biotite granodiorite, foliated porphrytic granodiorite, foliated fine biotite granodiorite and foliated leuco granite. Petrochemical data of these rocks suggest that Hamyang foliated granites is calc-alkali rock series of differentiated products of cogenetic magma by fractional crystallization. Igneous rocks of studied area correspond to I-type, peraluminous and calc alkali rock series. Rb-Sr age and $Sr^{87}/Sr^{86}$ initial ratio for foliated prophrytic granodiorite is $200{\pm}Ma$and $0.711{\pm}0.0037$, respectively. K-Ar(hornblende) age of hornblende diorite is $179{\pm}9Ma$. These data come to an coincidence with Igneous activity of South Korea which were proposed by O.J. Kim(1975), that is, they correspond to Hamyang foliated granites of products of Songrim Disturbance, and to hornblende diorite of Daebo Orogeny.

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Petrogenetic Study on the Foliated Granitoids in the Chonju and the Sunchang Area(I) -In the Light of Petrochemical Properties- (전주 및 순창지역에 분포하는 엽리상화강암류의 성인에 대한 연구(I) - 암석지화학적 특성을 중심으로 -)

  • Na, Choon-Ki;Lee, In-Sung;Chung, Jae-Il
    • Journal of the Korean earth science society
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    • v.18 no.6
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    • pp.480-492
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    • 1997
  • In order to understand the processes involved in the petrogenesis and the differentiation of the primary magma spectrum, a petrological and geochemical properties were investigated for the Chonju and the Sunchang foliated granites, which are located in the southwestern part of the Okchon zone and extends up to the northwestern boundary of the Ryongnam massif as two subparallel batholiths. Major element analyses show that the Chonju and Sunchang foliated granites are classified petrologically into a weakly to strongly peraluminous or calc-alkaline, but do not fit neatly into either of the I/S-type or magnetite/ilmenite-series classification schemes for granites, although the I-type and magnetite-series characteristics seem to be predominant based on the major element chemistry. In normative compositions, the Chonju granite is petrographically evolved from granodiorite to granite, whereas the Sunchang granite is from granodiorite to quartz monzodiorite. It seems to suggest a difference of the magmatic evolution processes such as crustal assimilation and/or fractional crystallization in magma. The REE patterns of both batholiths show high similarity and strongly fractionated REE distributions which show high $(Ce/Yb)_N$ ratios and little or no Eu anomalies. These REE patterns correspond broadly to those seen in the pre-Cretaceous granitoids of Korea. Apparently, the evidences obtained from the bulk compositions strongly suggest that the two foliated granitoids were formed by partial meltings of a relatively restricted and similar, may be common, source material which contains a continental crust component having an igneous composition, and have undergone a similar magmatic differentiation processes.

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