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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of the Petrological Society of Korea
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Journal DOI :
Petrological Society of Korea
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Volume & Issues
Volume 13, Issue 4 - Dec 2004
Volume 13, Issue 3 - Sep 2004
Volume 13, Issue 2 - Jun 2004
Volume 13, Issue 1 - Mar 2004
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Deformation History of Precambrian Metamorphic Rocks in the Yeongyang-Uljin Area, Korea
Kang Ji-Hoon ; Kim Nam Hoon ; Park Kye-Hun ; Song Yong Sun ; Ock Soo-Seok ;
The Journal of the Petrological Society of Korea, volume 13, issue 4, 2004, Pages 179~190
Precambrian metamorphic rocks of Yeongyang-Uljin area, which is located in the eastern part of Sobaegsan Massif, Korea, are composed of Pyeonghae, Giseong, Wonnam Formations and Hada leuco granite gneisses. These show a zonal distribution of WNW-ESE trend, and are intruded by Mesozoic igneous rocks and are unconformably overlain by Mesozoic sedimentary rocks. This study clarifies the deformation history of Precambrian metamorphic rocks after the formation of gneissosity or schistosity on the basis of the geometric and kinematic features and the forming sequence of multi-deformed rock structures, and suggests that the geological structures of this area experienced at least four phases of deformation i.e. ductile shear deformation, one deformation before that, at least two deformations after that. (1) The first phase of deformation formed regional foliations and WNW-trending isoclinal folds with subhorizontal axes and steep axial planes dipping to the north. (2) The second phase of deformation occurred by dextral ductile shear deformation of top-to-the east movement, forming stretching lineations of E-W trend, S-C mylonitic structure foliations, and Z-shaped asymmetric folds. (3) The third phase deformation formed I-W trending open- or kink-type recumbent folds with subhorizontal axes and gently dipping axial planes. (4) The fourth phase deformation took place under compression of NNW-SSE direction, forming ENE-WSW trending symmetric open upright folds and asymmetric conjugate kink folds with subhorizontal axes, and conjugate faults thrusting to the both NNW and SSE with drag folds related to it. These four phases of deformation are closely connected with the orientation of regional foliation in the Yeongyang-Uljin area. 1st deformation produced regional foliation striking WNW and steeply dipping to the north, 2nd deformation locally change the strike of regional foliation into N-S direction, and 3rd and 4th deformations locally change dip-angle and dip-direction of regional foliation.
Geochemical Approach to Define the Fracture Bone Affected by the Ubo Fault at the Northern Part of the Hwabuk Dam
Kwon Yong Wan ;
The Journal of the Petrological Society of Korea, volume 13, issue 4, 2004, Pages 191~200
The Ubo fault Bone, which cross over the northwestern to southeastern direction at the Hwabuk damsite in Hakseongri, Gunwigun, Gyeongsangbukdo Province, has length about 20km. The Ubo fault zone in this area is segmented to several small faults and makes a gentle slope and hill along the right side of the drainage in the Hwabuk dam. In the storage area of Hwabuk dam, 2 pairs of faults occur and the width of fracture zones are about 2m. To define the fracture Bone using the geochemical data, the samples were collected at 0.5m, 1m, 2m, 4m, 8m, 16m and 32m apart from the center of the main fracture Bone toward north and south, respectively, and analyzed for major elements and mineral content Approaching the fracture Bone, Fe
, MgO, K
O, quartz, muscovite and chlorite are increasing and Na
O, CaO, plagioclase and biotite are decreasing, respectively. Based on the rock chemistry and mineral content, the range of the main fracture zone affected by the Ubo fault at Hakseongri is 2m width in total, the secondary deformed zone is 8m width in total. Finally the maximum affected range by the Ubo fault is inferred to 16m width in total.
Geochemical Comparison Study on the Amphibolite in the Central Gyeonggi massif and Southeastern Okcheon metamorphic belt
Na Ki Chang ; Cheong Won Seok ;
The Journal of the Petrological Society of Korea, volume 13, issue 4, 2004, Pages 201~213
The Precambrian amphibolites in the central Gyeonggi massif, Yangsuri, Gyeonggido and southeastern Okcheon metamophic belt, Mungyeonggun, Gyeongsangbukdo, Korea, were studied on the geochemical characteristics of major and trace elements, and discussed petrogenetically and geotectonically. The characteristics of major elements of the amphibolites in these study areas are igeous origin such as tholeiitic-, subalkaline and alkaline basalt. Geotectonic distinction diagrams of trace elements such as Ti-Zr-Y and Zr-Nb-Y show basaltic igneous activity of island arc and mid ocean ridge environment at central Gyunggi massif, and within plate environment at southeastern Okcheon metamorphic belt. This result shows that genetic environments of study areas are different. Especially, origin of amphibolites in central Gyeonggi massif is similar with that of western Gyeonggi massif but different with the amphibolites of Chuncheon area. Genetic environment estimated of fractional crystallization of plagioclase has no particular effect on the origin of magma because value of LREE is higher than that of HREE and Eu anomaly definitely don't be exposed.
Oxygen and Hydrogen Isotopic Compositions of the Hwacheon Granite
Park Young-Rok ; Ko Bokyun ;
The Journal of the Petrological Society of Korea, volume 13, issue 4, 2004, Pages 214~223
Oxygen and hydrogen isotopic compositions of the Jurassic peraluminous Hwacheon granite were measured, and compared with those of other Jurassic peraluminous Daebo granite in Korea.
18/O values for quartz and feldspar of the Hwacheon granite range from 8.2 to 10.6 and 5.8 to 9.0
, respectively. Whole rock
18/O values for banded biotite gneiss country rocks surrounding the Hwacheon granites range from 8.1 to 9.4
. Whole rock and biotite
D Values for Hwacheon granite range from -84 to -113 and -107 to -113
, respectively. Whole rock
D values for banded biotite gneiss country rocks range from -76 to -100
D values of the Hwacheon granite are characterized by low values compared to the 'normal' values for the fresh peraluminous granitic rocks. Low
18/O values of the Hwacheon granite resulted from fluid-rock interaction for a long period. Isotopic modelling result renders that a relatively low-
18/O fluid below -1
was involved in subsolidus isotopic exchange under a relatively high fluid/rock ratio (<-6). The fluid of meteoric origin has experienced a modification of oxygen isotopic composition as a result of fluid-rock interaction with the Hwacheon granite and surrounding metapelitic country rocks.
Oxygen and Hydrogen Isotope Studies of Fluid-Rock Interaction of the Radons-Sancheong Anorthositic Rocks
Park Young-Rok ; Ko Bokyun ; Lee Kwang-Sik ;
The Journal of the Petrological Society of Korea, volume 13, issue 4, 2004, Pages 224~237
The anorthositic rocks of the study area are divided into the northern Sancheong and southern Hadong anorthositic rocks depending on the different distribution patterns and lithologies. In order to evaluate the characteristics of the hydrothermal systems developed in the study area, oxygen and hydrogen isotopic compositions of the anorthositic rocks were measured. Oxygen isotopic values of the plagioclase exhibit an interesting spatial distribution. Plagioclase collected from the Sancheong anorthositic rocks in the northern part tends to have a relatively restricted range of
values between 7.3 and 8.8
, which are heavier than 'normal'
) typical for plagioclase of the fresh mantle-derived anorthosite, whereas plagioclase from the southern part is characterized by a wide range of
values between -4.4 and 8.2
and much lighter values than 'normal' value for plagioclase of the fresh mantle-derived anorthosite. Plagioclase from the middle part has
values heavier than the plagioclase from the southern part, but lighter than that from the northern part. The spatial distribution of
values suggests that the decoupled hydrothermal flow systems might have been developed in the study area. Meteoric water dominated in the hydrothermal flow systems developed in the southern area, whereas magmatic fluid dominated in the northern area. The relationship between water content and hydrogen isotopic composition of anorthosites shows a positive correlation. The positive correlation indicates that fluids exsolved from magma during magmatic differentiation caused deuteric alteration of anorthositic rocks involving replacement of pyroxenes to amphiboles. After the deuteric alteration, hydrothermal system developed by meteoric water dominated the southern area, and erased record of the hydrothermal system developed by magmatic fluid at earlier stage. However, the development of meteoric hydrothermal system has been limited in the southern area only, and could not affect the Sancheong anorthositic rocks in the northern area. The abundant occurrences of secondary alteration minerals such as sericite, calcite, and chlorite in the southern Hadong anorthosite relative to the northern Sancheong anorthositc seem to be related to the overlapping of two distinct hydrothermal systems in the southern area.
Abundane of Rare Earth Element in Duwon Meteorite and Its Geochchemical Significance
Lee Seung-Gu ; Kim Kun-Han ; Choi Byeon-Gak ;
The Journal of the Petrological Society of Korea, volume 13, issue 4, 2004, Pages 238~243
Duwon meteorite was fallen on 23 November 1943 in Duwonmyeon, Goheung, Jeolanam-Do. We measured rare earth element abundance of Duwon meteorite by isotope dilution thermal ion mass spectrometry (ID-TIMS) and ICP-MS. As a result, except La and Ce, abundance of other rare earth element show a correspondence within 10％ of error range. However, La and Ce show more than 70％ in abundance, which is considered due to 1) experimental procedure or 2) inhomogeneity of sample. Leedey meteorite was fallen on 25 November 1943 in Dewey County, Oklahoma, USA. which suggested that fallen difference between Leedey and Duwon meteorites is only 2 days. Leedey and Duwon meteorites are classified as ordinary chondrite of L6 type. In Leedey chondrite-normalized REE pattern, Duwon meteorite shows nearly flattened, which suggests close relationship between Leedey and Duwon meteorites meteoritically or cosmochemically.
The Problem of Archean Age from a Metaigneous Recks in the Gyemyeongsan Formation, Northwestern Okcheon Metamorphic Belt and Its Reinterpretation
Park Jong Gil ; Kim Sung Won ; Oh Chang Whan ;
The Journal of the Petrological Society of Korea, volume 13, issue 4, 2004, Pages 244~246