• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.196.2-196
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• 2003

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.105-110
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• 2008

Process of the hydroxyapatite (HA) formation on bioactive titanium metal prepared by NaOH treatment in a modified-simulated body fluid (mSBF) containing bovine serum albumin (BSA) was investigated by high resolution transmission electron microscope attached with energy dispersive X-ray spectrometer (EDX). The amorphous titanate, which was formed on titanium surface by NaOH treatment, combined with the calcium ions in the liquid to form an amorphous calcium titanite. With increasing of soaking time in the liquid, an amorphous calcium titanite combined with the phosphate ions to form an amorphous calcium phosphate with low Ca/P atomic ratio, and it grows as aggregates of plate (or needle)-like substance on titanium surface. The crystalline apatite layers, which are needle-shaped with the c axis parallel to the long axis, are formed in an amorphous calcium phosphate with further increase in soaking time. The formation of needle-shaped apatite layers can be explained by electrostatic effects and difference of concentration between calcium, phosphate, and albumin ions.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.195-214
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• 2020

The Samgwang Au-Ag deposit has been one of the largest deposits in Korea. The deposit consists of eight lens-shaped quartz veins which filled fractures along fault zones in Precambrian metasedimentary rock, which feature suggest that it is an orogenic-type deposit. The Ti-bearing minerals occur in wallrock (titanite, ilmenite and rutile) and laminated quartz vein (rutile). They occur minerals including biotite, muscovite, chlorite, white mica, monazite, zircon, apatite in wallrock and white mica, chlorite, arsenopyrite in laminated quartz vein. Chemical composition of titanite has maximum vaules of 3.94 wt.% (Al₂O₃), 0.49 wt.% (FeO), 0.52 wt.% (Nb₂O₅), 0.46 wt.% (Y₂O₃) and 0.43 wt.% (V₂O₅). Titanite with 0.06~0.14 (Fe/Al ratio) and 0.06~0.15 (X_Al (=Al/Al+Fe³⁺+Ti)) corresponds with metamorphic origin and low-Al variety. Chemical composition of ilmenite has maximum values of 0.07 wt.% (ZrO₂), 0.12 wt.% (HfO₂), 0.26 wt.% (Nb₂O₅), 0.04 wt.% (Sb₂O₅), 0.13 wt.% (Ta₂O₅), 2.62 wt.% (As₂O₅), 0.29 wt.% (V₂O₅), 0.12 wt.% (Al₂O₃) and 1.59 wt.% (ZnO). Chemical composition of rutile in wallrock and laminated quartz vein has maximum values of 0.35 wt.%, 0.65 wt.% (HfO₂), 2.52 wt.%, 0.19 wt.% (WO₃), 1.28 wt.%, 1.71 wt.% (Nb₂O₃), 0.03 wt.%, 0.07 wt.% (Sb₂O₃), 0.28 wt.%, 0.21 wt.% (As₂O₅), 0.68 wt.%, 0.70 wt.% (V₂O₃), 0.48 wt.%, 0.59 wt.% (Cr₂O₃), 0.70 wt.%, 1.90 wt.% (Al₂O₃) and 4.76 wt.%, 3.17 wt.% (FeO), respectively. Rutile in laminated quartz vein is higher contents (HfO₂, Nb₂O₃, As₂O₅, Cr₂O₃, Al₂O₃ and FeO) and lower content (WO₃) than rutile in wallrock. The substitutions of rutile in wallrock and laminated quatz vein are as followed : rutile in wallrock [(Fe³⁺, Al³⁺, Cr³⁺) + Hf⁴⁺ + (W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶ 2Ti⁴⁺ + V⁴⁺, 2Fe²⁺ + (Al³⁺, Cr³⁺) + Hf⁴⁺ + (W⁵⁺, As⁵⁺, Nb⁵⁺) ⟵⟶ 2Ti⁴⁺ + 2V⁴⁺], rutile in laminated quartz vein [(Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺ + V⁴⁺, (Fe³⁺, Al³⁺) + As⁵⁺ ⟵⟶ Ti⁴⁺ + Hf⁴⁺, 4(Fe³⁺, Al³⁺) ⟵⟶ Ti⁴⁺ + (W⁵⁺, Nb⁵⁺) + Cr³⁺], respectively. Based on these data, titanite, ilmenite and rutile in wallrock were formed by resolution and reconcentration of cations (W⁵⁺, Nb⁵⁺, As⁵⁺, Hf⁴⁺, V⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺) in minerals of wallrock during regional metamorphism. And then rutile in laminated quartz vein was formed by reconcentration of cations (Nb⁵⁺, As⁵⁺, Hf⁴⁺, Cr³⁺, Al³⁺, Fe³⁺, Fe²⁺) in alteration minerals (white mica, chlorite) and Ti-bearing minerals reaction between hydrothermal fluid originated during ductile shear and Ti-bearing minerals (titanite, ilmenite and rutile) in wallrock.

• Economic and Environmental Geology
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• v.50 no.1
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• pp.35-44
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• 2017

The Hadong-Sancheong Proterozoic anorthosite complex occurs in the southwestern region of the Ryongnam massif. The geology of the area mainly consists of metamorphic rocks of the Jirisan metamorphic complex as basement rocks, charnockite, and the Hadong-Sancheong anorthosite, which are intruded by the Mesozoic igneous rocks. Hadong-Sancheong anorthosite complex is divided into the Sancheong anorthosite and the Hadong anorthosite which occur at north-southern and south area of the Jurassic syenite, respectively. The Hadong Fe-Ti-bearing dike-like ore bodies developed intermittently in the Hadong anorthosite with north-south direction and extend about 14 km. The Hadong Fe-Ti-bearing ore bodies consist mainly of magnetite and ilmenite with rutile, titanite, and minor amounts of sulfides(pyrrhotite, pyrite, chalcopyrite and sphalerite). The Hadong Fe-Ti-bearing ore bodies show a paragenetic sequence of magnetite-ilmenite ${\rightarrow}$ magnetite-ilmenite-pyrrhotite ${\rightarrow}$ ilmenite-pyrrhotite-rutile-titanite(and/or pyrite) ${\rightarrow}$ sulfides. Equilibrium thermodynamic interpretation of the mineral paragenesis and assemblages indicate that early Fe-Ti-bearing ore mineralization in the ore bodies occurs at about $700^{\circ}C$ which corresponds to oxygen fugacity of about $10^{-11.8}{\sim}10^{-17.2}$ atm with the decrease tendency of sulfur fugacity to about $10^0$ atm as equilibrium of $Fe_3O_4-FeS$. The change of ore mineral assemblages from Fe-Ti-bearing minerals to sulfides in late ore mineralization of the ore bodies indicates that oxygen fugacity would have slightly decreased to ${\geq}10^{-20.2}$ atm and increased sulfur fugacity to ${\geq}10^0$ atm.

• Journal of the Korean Ceramic Society
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• v.23 no.6
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• pp.33-36
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• 1986

The $PbTiO_3$is well known materials having remarkable ferroelectric piezoelectric and pyro-electric properties. Thin films of the lead titanite has been successfully fabricated by Chemical Vapor Deposition on the borosilicate glass and titanium substrate. The $PbTiO_3$ thin film deposited on the borosilicate glass using the $PbCl_2$, $TiCl_4$ dry oxygen and wet oxygen at different temperatures (50$0^{\circ}C$-$700^{\circ}C$) grows along the (001) preferred orientation. On the other hand the $PbTiO_3$ thin film deposited on the titanium substrate using the PbO grows along the (101) preferred orientation. Growth orientation of deposited $PbTiO_3$ depends on the reaction species irrespective of substrate materials. Maximum dielectic constant and loss tangent of the $PbTiO_3$ thin film deposited on the titanium substrate are about 90 and 0.02 respectively, . Deposition rates of $PbTiO_3$ deposited on the borosilicate glass and titanium substrate are 10-15 ${\mu}{\textrm}{m}$/hr. Titanium dioxide interlayer formed be-tween $PbTiO_3$ film and titanium substrate material, It improved the adhesion of the film.

• Economic and Environmental Geology
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• v.36 no.6
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• pp.407-413
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• 2003

The geology of the Apdong Nb-Ta deposit, is hosted by alkali metasomatites, consist of Upper Proterozoic sedimentary rocks, alkali syenites(Hoamsan intrusive) of Phyonggang Complex(late Paleozoic to early Mesozoic), Jurassic granite and Quaternary basalt. Alkali syenites are distinguished as alkali amphibole-pyroxene syenite, alkali amphibole-biotite syenite, biotite-nepheline syenite, biotite syenite, and quartz-alkali amphibole-pyroxene syenite. Alkali metasomatites are the products of intense post-magnatic metasomatism, and form the Nb-Ta ore bodies as the belt, irregular vein and lenticular types in the southern part of Hoamsan intrusive. The ore mineralization is characterized by the occurrence of pyrochlore, zircon, and small amounts of columbite, fergusonite. magnetite, fluorite, molybdenite, ilmenite, titanite, apatite, and monazite. Pyrochlore is one of the niobium/tantalum oxides and contains substantial amounts of rare earths and radioactive elements. The compositional varieties of pyrochlore can be defined: (1) enriched in tantalum, uranium and cerium, (2) substantially tantalum- and fluorine-poor, and (3) enriched in thorium or barium. The geochemical characteristics, ore textures and mineral occurrences indicate that alkali metasomatism of the mineralizing fluid was the dominant ore-forming process.

• Economic and Environmental Geology
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• v.54 no.6
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• pp.629-647
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• 2021

Located in the eastern part of the Anti-Atlas, the Tafilalet region shows numerous dykes and sills that crosscut the Paleozoic terrains. The magmatic structures (dykes and sills) of the Tadaout-Tizi n'Rsas (TTR) anticline is studied here, it located neighboring the main branch of the Anti-Atlas Major Fault (AAMF), known in this location as the Oumejrane-Taouz Fault (OJTF). The N20° to N60° trending dykes crosscut the Paleozoic formations (Ordovician to Devonian), whereas sills are injected into the Silurian and Devonian ones. The dyke swarms of TTR have been studied using the Anisotropy of Magnetic Susceptibility (AMS), petrographic study and structural analyses. The petrographic study of the TTR doleritic dykes shows a dominance of plagioclase feldspars, alkali feldspars, amphiboles, pyroxenes and biotite. The dykes contain also mesotype (natrolite), sphene (titanite), apatite, actinolite and pegmatitic enclaves of biotite, orthoclase feldspars and pelites. Concerning field works, they show the deformation of TTR dykes by the Variscan tectonics events, it is marked by the presence of displacements (strike-slip faults) and cleavages. The Magnetic Susceptibility (MS) measured on magmatic specimens show the dominance of ferromagnetic and paramagnetic minerals. The high values of MS in the dykes are due to the presence of hematite, amphibole, pyroxene and biotite. In addition their magnetic fabric, determined by our AMS study, allows us to reconstitute the tectonic event which affected the magmatic bodies. This one is characterized by a magnetic foliation and a NNW-trending lineation that reflect the Variscan shortening orientation.

• The Journal of the Petrological Society of Korea
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• v.23 no.3
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• pp.239-247
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• 2014

The (U-Th)/He dating utilizes the production of alpha particles ($^4He$ atoms) during natural radioactive decays of $^{238}U$, $^{235}U$ and $^{232}Th$. (U-Th)/He age can be determined from the abundances of the parent nuclides $^{238}U$, $^{235}U$ and $^{232}Th$ and the radiogenic $^4He$. Because helium is one of the noble gases (non-reactive) with a relatively small radius, it diffuses rapidly in many geological materials, even at low temperatures. Therefore, ingrowth of $^4He$ during radioactive decay competes with diffusive loss at elevated temperatures during the geologic time scale, determining the amount of $^4He$ existing today in natural samples. For example, He diffusion in apatite is known to be very rapid compared to that in most other minerals, causing a significant diffusive loss at ${\sim}80^{\circ}C$ or higher. At ${\sim}40^{\circ}C$, He diffusion in apatite becomes slow enough to preserve most $^4He$ in the sample. Thus, an apatite's (U-Th)/He age represents the timing when the sample passed through the temperature range of $80-40^{\circ}C$. The crustal depth corresponding to this temperature range is called a "partial retention zone." Normal closure temperatures for a typical grain size and cooling rate are ${\sim}60-70^{\circ}C$ for apatite and ${\sim}200^{\circ}C$ for zircon and titanite. Because the apatite He closure temperature is lower than that of most other thermochronometers, it can provide critical constraints on relatively recent or shallow-crustal exhumation histories.

• The Journal of the Petrological Society of Korea
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• v.4 no.1
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• pp.1-19
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• 1995

In order to characterize the petrogenesis of the E-W trending Imjinganag belt, we studied the metamorphic rocks of the Yeoncheon Group near its type locality, Yeoncheon - Cheongok area, belonging to the southern part of this fold-thrust belt. The Samgot Formation of the Yeoncheon Group consists of calc-silicate and metapsammitic rocks together with amphibolite and amphibole gneiss. Layers of these metamorphic rocks concordantly occur in a wide area with its length greater than 15 km along their strike direction. Major mineral assemblages of the amphibolite are hornblende + plagioclase ${\pm}$ garnet ${\pm}$ diopside ${\pm}$ biotite ${\pm}$ quartz. Accessory rutile and ilmenite are characteristically replaced by titanite. Metamorphic temperatures and pressures estimated from the garnet - hornblende - plagioclase - quartz geothermo-barometers are 632-$736^{\circ}C$ and 7.9-11.1 kbar, respectively. Thus, the regional metamorphism of the study area belongs to the upper amphibolite facies. Furthermore, Sm-Nd and Rb-Sr data of garnet, plagioclase, and whole rock of an amphibolite define mineral isochrons of $231{\pm}30$ Ma and $222{\pm}24$ Ma, respectively, suggesting the Triassic metamorphism. These results are consistent with P-T conditions and metamorphic ages reported in the Shandong Peninsula, and support the hypothesis that the Chinese collision belt may extend into the Imjingang belt in the Korean Peninsula.

• The Journal of the Petrological Society of Korea
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• v.11 no.3_4
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• pp.103-120
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• 2002

In the Baekdong-Hongseong area, the southwestern part of the Gyeonggi Massif in Korea, ultramafic rocks occur as lenses within Precambrian granitic gneiss. At Baekdong area, ultramafic lens contains metabasite boudin which had undergone at least three stages of metamorphisms. The mineral assemblage on the first stage, Garnet+Sodic Augite+Hornblende+Plagioclase+Titanite, is recognized from the inclusions in garnet. The second stage is represented by the assemblage in matrix, Garnet+ Augite+Hornblende+Plagioclase, while the third stage is identified by the Hornblende+Plagjoclase $\pm$ Garnet assemblage in the symplectite formed around garnet. The P-T conditions of the first and the third stages are $690-780^{\circ}C$, 11.8-15.9 kb and $490-610^{\circ}C$, 4.0-6.3 kb, respectively. These data indicate that metabasite in Baekdong area had experienced a retrouade P-T path from the eclogite(EG) - high-pressure granulite (HG)-amphibolite (AM) transitional facies to the AM through HG-AM transitional facies. The core and rim of garnet in country granitic gneiss give $605-815^{\circ}C$, 10.7-16.0 kb and $575-680^{\circ}C$, 5.4-7.0 kb, respectively, indicating that the retrograde P-T path of granitic gneiss is similar to that of metabasite. Trace element data reveals that the tectonic setting of metabasite is island uc. The general geology, the metamorphic evolution, the mineral chemistry and the tectonic setting of Baekdong area indicate that the Baekdong-Hongseong area in Korea is a possible extension of the Sulu collision Belt in China. On the other hand, the Sm-Nd whole rock-garnet isochron ages of metabasites are 268.7-297.9 Ma which are older than the ages of UHP metamorphism (208-245 Ma) in the Dabie-Sulu Collision Belt. The older metamorphic ages suggest that collision between Sino-Korea and Yangtz plates may have occurred earlier in Korean Peninsula than China.