• Journal of the Mineralogical Society of Korea
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• v.27 no.4
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• pp.197-205
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• 2014

Study area (Jikjeon-ri) is located in south end of the Hadong anorthositic rocks. And along the south-western boundary, diorite intruded the Hadong anorthosite. Ilmenite ore bodies are extended in both anorthosite and diorite. And their occurrence in the diorite are not studied yet. While no particular textures are found in the ilmenite within the anorthosite, the ilmenite within the diorite shows characteristic exsolution texture, that is, ilmenite phases are separated into rutile and Fe-oxide and the ilmenite and Fe-oxide. MnO composition in ilmenite ratios are 2.14~3.74wt%, it has higher composition in diorite than that in anorthosite. The plagioclase composition display andesine ($An_{28.7-42.9}$) in the diorite and labradorite ($An_{57.1-72.8}$) in the anorthosite in composition. The exsolution of ilmenite has been developed during the cooling of partly melted ilmenite into rutile and Fe-oxides which is related to the intrusion of the diorite.

• Economic and Environmental Geology
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• v.35 no.1
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• pp.13-23
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• 2002

The chemical compositions of groundwaters from the granite areas mainly belong to Ca-HC0$_{3}$ and Na-HC0$_{3}$type, and some of these belong to Ca-(CI+S0$_{4}$) and Na-(CI+S0$_{4}$) type. Spring waters and groundwaters from anorthosite areas belong to Ca-HC03 and Na-HC03 type, respectively. The result of reaction path modeling shows that the chemical compositions of aqueous solution reacted with granite evolve from initial Ca-CI type, via CaHC0$_{3}$ type, to Na-HC0$_{3}$ type. The result of rain water-anorthosite interaction is similar to evolution path of granite reaction and both of these results agree well with the field data. In the reaction path modeling of rain watergranite/anorthosite reaction, as a reaction is progressing, the activity of hydrogen ion decreases (pH increases). The concentrations of cations are controlled by the dissolution of rock-forming minerals and precipitation and re-dissolution of secondary minerals according to the pH. The continuous addition of granite causes the formation of secondary minerals in the following sequence; gibbsite plus hematite, Mn-oxide, kaolinite, silica, chlorite, muscovite (a proxy for illite here), calcite, laumontite, prehnite, and finally analcime. In the anorthosite reaction, the order of precipitation of secondary minerals is the same as with granite reaction except that there is no silica precipitation and paragonite precipitates instead of analcime. The silica and kaolinite are predominant minerals in the granite and anorthosite reactions, respectively. Total quantities of secondary minerals in the anorthosite reaction are more abundant than those in the granite reaction.

• Journal of the Mineralogical Society of Korea
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• v.6 no.2
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• pp.145-155
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• 1993

Mineralogical, textural, and chemical changes of chlorite by weathering in anorthosite in the Sancheong district were stucdied using X-ray diffraction, scanning electron microscopy, and electron microprobe analysis. Chlorite in anorthosite corresponds to ferroan clinochlore with IIb structural type. It weatheres firstly to regularly mixed-layered chlorite/vermiculite(C/V) and then, to halloysite without the intermediate stage of vermiculite. Clinochlore packet cleaves and transforms to several thin packets of C/V, which subsequently change to halloysite developint fan-sharped structures by large volume increase. Direct halloysitization of C/V is attributed to the rapid weathering of anorthosite.

• Journal of the Korean earth science society
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• v.27 no.5
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• pp.528-538
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• 2006

Main aspect of this study is to clarify the petrochemistry and petrogenesis of intermediated-basic plutons located in the southwestern part of the Korean peninsula. These Intermediated-basic plutons consist of Pre-Cambrian anorthosite-gabbro, Triassic hornblende gabbro (Jirisan area), Jurassic diorite-syente (Jirisan and north area) and Cretaceous gabbro-diorite (south area). The Massif type anorthosite has multi intrusions, where each one intruded by gabbroic rocks, composed of gabbro, norite, troctolite and leucogabbro. In the variation diagram of the major-minor composition, AMF and Pl-Px-Ol diagrams, we suggest that intermediated-basic plutons in the southwestern part of the Korea show a trend consistent to Daly's value and calc-alkaline rock series. Accoding to REE (La/Yb)cw and Eu/Sm, these plutons are enriched with LREE than HREE, and emplaced by the tectonic setting in continent and/or continental margin.

• The Journal of the Petrological Society of Korea
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• v.20 no.2
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• pp.115-135
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• 2011

Fe-Ti ore bodies and mafic granulite occur in the Sancheong anorthosites, south Korea. In order to determine their petrogenetic relationship and to classify the Fe-Ti ore bodies, we have synthetically analyzed characteristics in the field, such as distribution and occurrence, and petrologic features through detailed outcrop sketches. The ore bodies are divided into the regular vein dike- and irregular veinlet swarm types, according to their characteristics of contact with the anorthosites and internal structures. The former shows the tabularly intrusive contact and the pervasively ductile-sheared interior, while the latter, the irregularly tortuous contact and the almost intact interior. Most of the ore bodies are cross-cutting the foliation of the anorthosites and possess abundant anorthositic xenoliths, indicating their intrusion after the formation of foliation in the anorthosites. The mafic granulite, also bearing abundant anorthositic xenoliths, shows interior foliations nearly parallel to intrusion contact, and has abundant ilmenites approximately the same as those of the Fe-Ti ore bodies in chemical composition. And its intrusion into adjacent anorthosites is observed and the intrusion is finally changed into an irregular veinlet swarm type ore body. It is, thus, interpreted that the granulite in the study area was the host material of Fe-Ti ore bodies.

• Proceedings of the Petrological Society of Korea Conference
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• 2000.05a
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• pp.85-85
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• 2000

• Proceedings of the Petrological Society of Korea Conference
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• 2006.05a
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• pp.58-58
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• 2006

• The Journal of the Petrological Society of Korea
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• v.12 no.4
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• pp.207-209
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• 2003

The Honam Shear Zone, an important feature in the Phanerozoic geologic history of Korea, has attracted much attention due to its potential tectonic significance. However, little has been known about the displacement amount of the shear zone. Here, we propose a possible displacement marker for the shear zone. The geographic position and peculiar lithology of the Sancheong and Gaya anorthosite bodies in the south-central part of Korea suggest a NE-trending dextral strike slip shear zone that has a displacement of ca. 50 km. This hypothetical shear zone is considered as a part of the Honam Shear Zone since the former has the same trend and shear sense as the latter.

• The Journal of the Petrological Society of Korea
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• v.25 no.4
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• pp.389-400
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• 2016

The study area, which is located in the southeastern part of the Jirisan province of the Yeongnam massif, Korea, consists mainly of the Precambrian Sancheong anorthosite complex and the Jirisan metamorphic rock complex, the Mesozoic granitoids which intruded them. Several fracture sets with various geometric indicators, which determine their relative timing and shear sense, are well observed in the Sancheong anorthosite complex. The aim of this study is to determine the development sequence of extension fractures, the movement sense and development sequence of shear fractures in the Sancheong anorthosite complex on the basis of detailed analysis of their geometric indicators. This study suggests fracture system of the Sancheong anorthosite complex was formed at least through five different fracturing events, named as Dn to Post-Dn+3 phases. (1) Dn phase: extension fracturing event of NNW trend. The fracture set experienced the reactivations of dextral ${\rightarrow}$ sinistral shearing with the change of stress field afterward. (2) Dn+1 phase: extension fracturing event of (N)NE trend. The fracture set experienced the reactivations of sinistral ${\rightarrow}$ sinistral ${\rightarrow}$ dextral. (3) Dn+2 phase: extension fracturing event of NW trend. The fracture set experienced the activated of dextral shearing. (4) Dn+3 phase: extension fracturing event of N-S trend. (5) Post-Dn+3 phase: extension fracturing event of (E)NE trend. Dn deformation formed during the early Songnim orogeny. Dn+1 deformation formed during the late Songnim orogeny. Dn+2 deformation formed during the Daebo orogeny. Dn+3 deformation formed during the Bulguksa orogeny.

• Economic and Environmental Geology
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• v.48 no.6
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• pp.431-449
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• 2015

The study area is located in the western part of the Precambrian stock type of Sancheong anorthosite complex, the Jirisan province of the Yeongnam massif, in the southern part of the Korean Peninsula. We perform a detailed field geological investigation on the Sancheong anorthosite complex, and report the characteristics of lithofacies, occurrences, foliations, and research formation process and its mechanism of the Sancheong anorthosite complex. The Sancheong anorthosite complex is classified into massive and foliation types of Sancheong anorthosite (SA), Fe-Ti ore body (FTO), and mafic granulite (MG). Foliations are developed in the Sancheong anorthosite complex except the massif type of SA. The foliation type of SA, FTO, MG foliations are magmatic foliations which were formed in a not fully congealed state of SA from a result of the flow of FTO and MG melts and the kinematic interaction of SA blocks, and were continuously produced in the comagmatic differentiation. The Sancheong anorthosite complex is formed as the following sequence: the massive type of SA (a primary fractional crystallization of parental magmas under high pressure)${\rightarrow}$ the foliation type of SA [a secondary fractional crystallization of the plagioclase-rich crystal mushes (anorthositic magmas) primarily differentiated from parental magmas under low pressure]${\rightarrow}$the FTO (an injection by filter pressing of the residual mafic magmas in the last differentiation stage of anorthositic magmas into the not fully congealed SA)${\rightarrow}$the MG (a solidification of the finally residual mafic magmas). It indicates that the massive and foliation types of SA, the FTO, and the MG were not formed from the intrusion and differentiation of magmas which were different from each other in genesis and age but from the multiple fractionation and polybaric crystallization of the coeval and cogenetic magma.