• 자원환경지질
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• 제27권3호
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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.

• 자원환경지질
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• 제32권6호
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• pp.669-688
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• 1999

The Yeongju granitoid batholith is a plutonic complex of huge area (1180km2) intruding the metamorphic rocks of the Yeongnam massif. The batholith, which is divided into fivelithofacies, consists of three separate plutons. The oldest Buseok pluton comprises four lithofacies: hornblende biotite tonalite, porphyrotoc biotite granodiorite, equigranular biotite grandiorite and biotite granite. The middle Chunyang pluton has been called as Chunyang granite that ranges in compostion from granodiorite to granite. The youngest Jangsu pluton is intrusions that has lithofacies of two mica granite. The contact between Buseok pluton and the rest two plutons shows obvious intrusive relations, but relation between the Chunyang and the Jangsu pluton is far away, so gives no indication of relative ages. Changes in nextures and micristructures, as well as in the mineral contents, take place between rock types og the plutons. only the Buseok pluton shows faliations of two type: magmatic foliation and regional mylonal foliation. K-Ar age deteminations fall into 171.7$\pm$3.2~162.3$\pm$3.1 Ma in the Buseok pluton, 153.9$\pm$2.9 Ma in the Chunyang pluton and 145.3$\pm$2.7 Ma in the jangsu Pluton. The batholith presents three separate intrusive phases which range in composition from tonalite to granite to granite. Each intrusive phase apperars to have been intruded in a pulse from an underlying, differentiating magma. The petrochemical data showthat three plutons are within the diagnostic range for continental arc orogenic tectonic setting, whereas Jangsu pluton approaches postorogenic setting. The data suggest that three plutons are calc-aclkalline series, and that temporal compositional variations change progerssively from tonalite through grandiorite to granite between the intrusive phases. so we consider that the magmas for all the phases were probably derived from a differentiation by fractional crystallization of a parental magma. The tonalite magma of the Buseok phase was tapped was tapped from a chamber deep in the crust, and then would have to rise at a rapid rate to its final level of emplacement. The tonalite magma in the chamber was gradually enolved through granodiorite magma into granite magma by fractional crystallization. The magmas of the younger phases were respectively tapped with temporal interval from a evolved magma of the chamber that rose into a shallower lever in the crust, and rose to their present level of emplacement.

• 자원환경지질
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• 제26권1호
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• pp.83-96
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• 1993

Kwangju granite body located in vicinity of Kwangju city consist of three rock bodies-Kwangju rock body, Jangsung rock body and Youngkwang rock body. Petrochemistry of Kwangju granite is as follows: Kwangju granite body is igneous complex which compose of a series of differential products of a magma. Kwangju granites are divided into four rock facies based on the geologic age, mineralogical and chemical constituents and texture: Triassic hornblende-biotite granodiorite and biotite granite, and Jurassic porphyritic granite and two mica granite. Harker and other variation diagrams of Kwangju granites plot on trend of calc-alkali rock series and range of peraluminous granite. Parental magma type of Kwangju granites correspond to I-type, Syn-Collision type in compressive stress field by collision movement between both rock block. In chondrite normalized REE patterns of Kwangju grnites, LREE enriched than HREE in REE amount and have more steep negative slope with slightly (-) Eu anormaly.

• 자원환경지질
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• 제28권5호
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• pp.445-454
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• 1995

The petrochemical data of the porphyritic granites of Cretaceous age in the Yonghwa-Seolcheon area show the trend of subalkaline magma, calc-alkaline magma, I-type granitoid and magnetite series. This granite is the relevant igneous rock of gold-silver mineralization in this mining district Fluid inclusions have been studied in phenocryst quartz from the Cretaceous porphyritic granite. Three main types of fluid inclusion were found : liquid-rich inclusion(I type), gas-rich inclusion(II type) and solid-bearing inclusions(III-A, III-B). The solid-bearing inclusions(III-A,B) represent the earliest trapped fluids. They have salinities between 41.0 and 67.5 wt% equivalent to NaCl. These are high saline inclusions containing NaCl and KCl daughter crystals. Homogenization temperature inferred from the fluid inclusion study ranges from 650 to $75^{\circ}C$ Type I and II inclusions were observed within the same fracture. This cause for these differences in degree of filling is evidence of boiling. Salinities of type I and II inclusions range from 9.87 wt% to 15.29 wt%, from 8.40 wt% to 14.64 wt% NaCl equivalent, respectively.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2000년도 춘계 공동학술발표회
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• pp.110-110
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• 2000

Temporal and spatial distribution patterns of the magmatic rocks and associated ore deposits in the Mesozoic magmatic - metallogenic belt along the Yangtz River, Anhui Province are used to determine and discuss the crust - mantle interaction processes. The magmatic rocks are Cu - Au mineralized high - K calc - alkalic intermediate ¬acidic (CAK) and Fe - Cu mineralized high - Na alkalic - calc intermediate - basic intrusive rocks (FCN) in the central part of the belt and grade to Cu - Mo - Pb - Zn - Ag mineralized calc - alkalic granitoids (CMG) and A - type granites (AG) in the southern and northern parts of the belt. Samples from the CAK and CMG yield Rb - Sr isochron ages of 137 - 140Ma with $(^{87}Sr/^{86}Sr)_{o}$ = 0.7060 - 0.7101, while those from the FCN and AG yield the ages of 120 - 129Ma with $(^{87}Sr/^{86}Sr)_{o}$ = 0.7047 - 0.7077. The Sr isotope ratios, CriTh ratios 0.4 - 3.1), Eu/Eu* ratios < 0.79 - 1.05) and initial epsilon (Nd) values (-16.6 - -6.3) for the CAK and CMG are consistent with magma derivation from old metamorphic basement rocks rich in metallogenic elements through a two - stage process of mantle - derived magma underplating caused by primary lithosphere extension and subsequent partial melting. On the basis of Sr isotope data, CriTh ratios (3.4 - 13.8), Eu/Eu* ratios (0.86 - 1.13) and initial epsilon (Nd) values (-7.7 - +1.4), the FCN and AG are considered to be formed through syntexis with material input from the mantle that resulted from further lithosphere extension followed by mantle - derived magma underplating on a large scale.

• 자원환경지질
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• 제25권4호
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• pp.447-461
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• 1992

본 역의 쥬라기화강암류는 "편마상화강암"과 "대보화강암"으로 분류 (1 : 250,000 전주도폭, 1973) 되어져 있으나, "대보화강섬록암"은 본 연구에서의 거창화강섬록암에 해당된다. 이들 화강섬록암류에 대한 조암광물의 경하기재, 암석화학, 및 저어콘의 형태적 연구를 하였다. 모드조성상 이들은 주로 화강성록암에 해당되지만 편마상화강섬록암은 Trondhjemitic trend를, 거창화강섬록암은 granodioritic trend를 각각 따른다. 이들 두 암체는 모두 칼크-알칼라인 계열이며 I-type (자철석계열)에 속하나, 편마상화강섬록암은 분화말기에 La, Ce, Yb의 enrichment를 겪은 반면, 거창화강섬록암은 분화초기에 Yb의 depletion을 겪은 것으로 생각된다. 사장석은 대체로 올리고클레이스에 해당한다. 흑운모는 (Mg, Fe) 고용체간의 성분변화보다 (Si, Al) 고용체간의 변화가 더 뚜렷하다. 각섬석은 거창화강섬록암에서만 제한적으로 산출되며 tschermakite에 해당한다. 저어콘 주면의 상대적 발달을 보면, 편마상화강섬록암은 대부분 {100}={110}형에 가까운 것들이 많으나, 거창화강섬록암은 {110} 탁월형 (저온형)에서 {100} 탁월형 (고온형)에 이르는 다양한 변화를 보인다. 그러나 이들은 대부분 저온형 마그마 용체내에서 결정화되었다. PPEF (Prism-Pyramid-Elongation-Flatness) 도에서, 편마상화강섬록암은 닫힌 가위형 (closed scissors type), 거창화강섬록암은 열린 가위행 (open scissors type)을 보인다. 이는 거창화강섬록암의 저어콘들이 지각물질 또는 편마상화강섬록암을 형성시킨 잔류마그마와 혼화된 마그마로부터 정출되었음을 암시해 주는 것으로 생각된다.

• 암석학회지
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• 제1권2호
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• pp.91-103
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• 1992

Eruptive mechanisms and processes at Udo tuff cone can be inferred from indicative characters of products, bedforms and lithofacies, and ring faults. In terms of bedforms and lithofa-cies in particular, massive lapilli tuff beds and chaotic lapilli tuff beds are derived from subaerial falls of aggregated tephra of wet tephra finger jets, occurring dominantly at the lower sequences of proximal part at the tuff cone. Crudely stratified lapilli tuff are derived from subaerial falls of slightly aggregated tephra of less wet tephra finger jets, whereas reversely graded lapilli tuff beds are from slightly disaggregated subaerial falls of continuous uprush. Both beds frequently occur in the middle sequences at proximal and near medial part of the tuff cone. Block and lapilli tephra lenses, ash-coated lapilli tephra beds(lenses) and thin-bedded tuff beds are derived from extremely disaggregated subaerial falls of dry tephra in the continuous uprush, frequently occurring at the upper sequences of medial part at the tuff cone. Udo tuff cone is a basaltic volcano emergent through the sea water surface while water could flood across or into the vent area. Emergence of the tuff cone was from the type-Surtseyan eruption characterized by earlier tephra finger jets and later continuous uprush columns of tephra with copious volumes of steam. Explosions began when boiling of wter produced a bubble column reducing the hydrostatic pres-sure, allowing exsolution of gases from the magma. This expansion of magma into a vesiculating froth fragmented the magma and permitted mixing of magma and water so that a more vigorous generation of steam could proceed. Tephra finger jetting explosions continued to build the crater rims, then remove water from the vent that their deposits flowed like slsurries until the continuous uprush explosion ensued. Continuous uprush explosions were associated with most rapid accumula-tion of tephra. The increasing volume rate led to partial removal of water from the vent area by the newly tephra ring so that more vigorous activity could be attended by a reducing water supply. This might restrain surplus of cold water entering the vent and thus enhance the vigour of the eruption by allowing optimal heat exchange. Eventually the crater became so deep and unsuported that piecemeal sliding, or massive subsidence on indipping ring faults, filled and closed the vent, and the cycle of explosions and collapse began anew.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권2호
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• pp.25-37
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• 2014

The volcanic type of geothermal water is linked intimately to active or potentially active volcanoes and takes place near the plate boundaries. In contrast to the volcanic type, the geothermal water in Korea has a non-volcanic origin. Korea's geothermal water is classified into the residual magma (RM) type and deep groundwater (DG) type according to the criterion of $35^{\circ}C$. This study reviewed the relationship between the physical and chemical features of the 281 geothermal water sources in South Korea in terms of the specific capacity, water temperature, and chemical compositions of two different basements (igneous rock and metamorphic rock) as well as the geological structures. According to the spatial relationship between the geothermal holes and geological faults, the length of the major fault is considered a key parameter determining the movement to a deeper place and the temperature of geothermal water. A negligible relationship between the specific capacity (Q/s) and temperature was found for both the RM type and DG type with the greater specific capacities of the RM- and DG-igneous types than the RM- and DG-metamorphic types. No relationship was observed between Q/s and the chemical constituents ($K^+$, $Na^+$, $Ca^{2+}$, $Mg^{2+}$, $Zn^{2+}$, $Cl^-$, $SO_4{^{2-}}$, $HCO_3{^-}$, and $SiO_2$) in the DG-igneous and DG-metamorphic types. Furthermore, weak relationship between temperature and chemical constituents was found for both the RM type and DG type.

• 한국지구과학회:학술대회논문집
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• 한국지구과학회 2005년도 추계학술발표회 논문집
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• pp.136-141
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• 2005

The K Ar ages, whole rock geochemistry and Sr Nd Pb isotopes have been determined for the submarine basalts dredged from the P2 and P3 segments of the Antarctic-Phoenix Ridge (APR), Drake Passage, Antarctica, for better understanding on temporal variation of magma chemistry in association with extinction of seafloor spreading. The fossilized APR is distant from the known hot spots, and consists of older N-MORB prior to extinction of spreading and younger E-MORB after extinction. The older N-MORB (3.5-6.4 Ma) occur in the southeast flank of the P3 segment (PR3) and the younger E-MORB (1.4-3.1 Ma) comprise a huge seamount at the P3 segment (SPR) and a big volcanic edifice at the P2 segment (PR2). The N-type PR3 basalts have higher Mg#, K/Ba, and CaO/Al2O3 and lower Zr/Y, Sr, and Na8.0 with slight enrichment in incompatible elements and almost flat REE patterns. The E-type SPR and PR2 basalts are highly enriched in incompatible elements and LREE. The extinction of spreading occurring at 3.3 Ma seems to have led to a temporal magma oversupply with E-MORB signatures. Geochemical signatures such as Ba/TiO2, Ba/La, and Sm/La suggest heterogeneity of upper mantle and formation of E-MORB by higher contribution of enriched materials to mantle melting, compared to N-MORB environment. E-MORB magmas beneath the APR seem to have been produced by low melting degree (up to 1% or more) at deeper low-temperature regime, where metasomatized veins consisting of pyroxenites have preferentially participated in the melting. The occurrence of E-MORB at the APR is a good example to better understand what kinds of magmatism would occur in association with extinction of spreading.

• 자원환경지질
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• 제31권4호
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• pp.349-360
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• 1998

The alkali granite occurred as small stock and dyke is distributed in the Kyeomyeongsan Formation in the vicinity of the Chungju city. Geochemical characteristics in major and trace element of alkali granite in the Kyeomyeongsan Formation indicate that the alkali granites are peralkaline and have similar geochemical features to the A-type alkali granite. The rock enriched in HFSE such as Zr, Nb, Y, REE etc. According to the discrimination diagram the alkali granites mostly belong to the within-plate granite field, and to the $A_1$ group of A-type granite. This suggests that they might be emplaced in a extentional rift environment. The alkali granites are characterized by remarkably high total REE content, and enriched, relatively flat to somewhat HREE-depleted patterns with large negative Eu anomaly. The Sm-Nd age of the alkali granite is $338{\pm}30Ma$ with ${\varepsilon}_{Nd(t)}$ beings -7.3 to -8.5. On the basis of the geochemical studies the source magma was derived from a enriched mantle-like source and had a few or clearly interaction with sialic continental crust. In conclusion, the alkali granitic rock of the Kyeomyeongsan Formation might be formed from the high F peralkaline magma that was emplaced in continental rift environment, and generated at the early Carboniferous.