• The Journal of the Petrological Society of Korea
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• v.22 no.2
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• pp.137-151
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• 2013

This study is focused on element behaviors and mineral compositions of the fault rock developed in Yongdang-ri, Yangbuk-myeon, Gyeongju City, Korea, using XRF, ICP, XRD, and EPMA/BSE in order to better understand the chemical variations in fault rocks during the fault activity, with emphasis on dependence of chemical mobility on mineralogy across the fault zone. As one of the main components of the fault rocks, $SiO_2$ shows the highest content which ranges from 61.6 to 71.0%, and $Al_2O_3$ is also high as having the 10.8~15.8% range. Alkali elements such as $Na_2O$ and $K_2O$ are in the range of 0.22~4.63% and 2.02~4.89%, respectively, and $Fe_2O_3$ is 3.80~12.5%, indicating that there are significant variations within the fault rock. Based on the chemical characteristics in the fault rocks, it is evident that the fault gouge zone is depleted in $Na_2O$, $Al_2O_3$, $K_2O$, $SiO_2$, CaO, Ba and Sr, whereas enriched in $Fe_2O_3$, MgO, MnO, Zr, Hf and Rb relative to the fault breccia zone. Such chemical behaviors are closely related to the difference in the mineral compositions between breccia and gouge zones because the breccia zone consists of the rock-forming minerals including quartz and feldspar, whereas the gouge zone consists of abundant clay minerals such as illite and chlorite. The alteration of the primary minerals leading to the formation of the clay minerals in the fault zone was affected by the hydrothermal fluids involved in fault activity. Taking into account the fact that major, trace and rare earth elements were leached out from the precursor minerals, it is assumed that the element mobility was high during the first stage of the fault activity because the fracture zone is interpreted to have acted as a path of hydrothermal fluids. Moving toward the later stage of fault activity, the center of the fracture zone was transformed into the gouge zone during which the permeability in the fault zone gradually decreased with the formation of clay minerals. Consequently, elements were effectively constrained in the gouge zone mostly filled with authigenic minerals including clay minerals, characterized by the low element mobility.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.304-304
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• 2007

고주파 모률에서 사용되는 기판소재는 저유전율과 낮은 loss 특성을 요구함으로 지속적인 연구를 필요로 한다. 지금까지의 ceramic/glass composite 에서 주로 사용된 ceramic filler는 Al2O3로 낮은 유전률을 구현에 한계가 있었다. Cordierite는 낮은 유전율 (${\varepsilon}_r$ < 4)을 나타내는 filler로서 그 가능성이 높지만 아직까지 보고된 결과들이 미흡한 실정이다. 따라서 본 연구에서는 cordierite filler와 SiO2-B2O3-Al2O3-RO (R : Zn, Sr, Ba, Ca)계의 glass를 혼합하여 LTCC용 기판소재로서의 가능성을 확인하고자 저온 동시소성이 가능한 소결온도인 $850^{\circ}C{\sim}1.000^{\circ}C$ 사이에서 소재의 소결실험을 진행하였다. 소결온도에 따른 상변화, 유전특성을 확인한 결과 filler로 사용된 cordierite상만이 관찰 되었으며 소결조건에 따라 5.0~5.5의 낮은 유전율과 1.000~1,500의 Q를 나타내는 것을 확인 하였다.

• Journal of the Korean institute of surface engineering
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• v.56 no.2
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• pp.152-159
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• 2023

The night visibility of pavement is being considered as a global issue in the field of traffic safety. Although the spreading glass beads on the lane paints has been mainly used to secure night-visibility by utilizing the effect of retroreflection, obvious shortcoming of this method is that retroflection does not occur in the range where the headlights do not reach the glass beads. The use of functional paints including phosphorescent constituents could be a solution for overcoming fore-mentioned problem. SrAl₂O₄ based chemicals have not only good phosphorescent property, but also are chemically stable compared to existing ZnS based materials. However, this chemicals also need the improvement due to slightly reduced luminous effect in time. Herein, we developed novel paints showing enhanced phosphorescent properties by putting rare earth elements such as Eu, Dy and Y into SrAl₂O₄. These prepared phosphorescent pigments have displayed improved properties in terms of durability and long afterglow. For instance, the property of afterglow has been persisted after 5 hours with luminace of 20.6 mcd/m².

• Korean Journal of Mineralogy and Petrology
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• v.35 no.3
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• pp.345-353
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• 2022

This study aimed to fundamentally understand changes of cell parameters of cation-exchanged mordenites using high resolution X-ray powder diffraction for studies that immobilization of various heavy metal cation using synthesis mordenite (Na_6.6Al_6.6Si_41.4O₉₆·20.4H₂O, Na-MOR). As a results of measurement by Thermogravimetric analysis (TGA), it was confirmed that 19.4, 20.4 water molecules per unit cell were present in monovalent-cation substituted MOR (Cs-MOR, Na-MOR), and 21, 23.1, 23.2 water molecules per unit cell were present in divalent-cation substituted MOR (Pb-MOR, Sr-MOR, Cd-MOR). The space group of all the samples were identified as Cmcm belonging to the orthorhombic crystal system. Compared to Na-MOR, starting material, relative peak intensity of (110) and (200) is significantly changed after cation substitution whereas peak position is almost similar. Also, (220) peak that was not found in Na-MOR was clearly observed in Pb-, Cd- and Sr-exchanged MOR. Thus, it was estimated that changes of atomic distribution usually occurred on ab-plane while changes of cell parameters were little. Detailed changes in the cell parameters of cation-exchanged mordenites were derived from whole profile fitting method using the GSAS suite program. Changes in the axial lengths and unit cell volume of cation substitution showed different relationship depending on ionic radius and charge number. In case of monovalent-cation substituted MOR, the length of a-axis increases whereas the length of b- and c-axis decrease by absorbed cation radius. In the case of divalent-cation exchanged MOR, the length of a-axis usually decreases while the length of b- and c-axis increases by cation radius. It was confirmed that unit cell volume of monovalent and divalent cation substituted MORs had an independent tendency by cation radius.

• 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.

• Ocean and Polar Research
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• v.26 no.2
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• pp.231-243
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• 2004

Sequential extraction was carried out on twenty two subsamples of three ferromanganese crusts from three seamounts (Lemkein, Lomilik, and Litakpooki) near the Marshall Islands in the western Pacific. The extraction was designed to fractionate Fe-Mn crust forming elements into low defined groups: (1) exchangeable and carbornate, (2) Mn-oxide, (3) Fe-oxyhyd.oxide, and (4) residual fraction. X-ray diffraction result shows that target material were well removed by each extraction step except for CFA in phosphatized crusts generation. According to chemical analysis of each leachate, most of elements in the Fe-Mn crusts are bound with two major phases. Mn, Ba, Co, Ni, Zn, (Fe, Sr, Cu, and V) are strongly bounded with Mn-oxide $({\delta}-MnO_2)$ phase, whereas Fe, Ti, Zr, Mo, Pb, Al, Cu,(V, P, and Zn) show chemical affinity with Fe-oxyhydroxide phase. This result indicates that significant amount of Al, Ti, and Zr can not be explained by detrital origin. Ca, Mg, K, and Sr mainly occur as exchangeable elements and/or carbonate phase. Outermost layer 1 and inner layer 2 which are both young crusts generations are similar in chemical speciations of elements. However, some of Fe-oxyhydroxide bounded elements (Pb, Y, Mo, Ba, Al, and V) in phosphatized innermost layer 3 are released during phosphatization and incorporated into phosphate (Pb, Y, Mo, and Ba) or Mn-oxide phase (Al and V). Our sequential extraction results reveal that chemical speciations of elements in the hydrogenetic crusts are more or less different from interelemental relationship calculated by statistical method based on bulk chemistry.

• Journal of Fisheries and Marine Sciences Education
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• v.19 no.1
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• pp.1-7
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• 2007

The purpose of this study was to investigate geochemical characteristics of surface sediments in the Keum river estuary adjacent to coastal area. For this study we collected the 21 surface sediments samples. Mean size of surface samples was $3.24{\sim}6.65{\phi}$ on inner estuary and was $2.15{\sim}3.42{\phi}$ on outside estuary. Surface samples were composed of silt on inner estuary and were composed of sand which was more larger than $4{\phi}$ on outside estuary. Most major elements except CaO, $Na_2O$ showed good relationships between variation of contents and grain size. Contents of $Al_2O_3$, $Fe_2O_3$, MgO, $K_2O$, $TiO_2$, $P_2O_5$ and $M_nO$ were increased predominately owing to the variation of mean size of surface samples. Contents of Co, Cr, Cu, Li, Sr, Zn, La, Ce, Pb, Rb, Nd have a good relationships with grain size but Ba, Th, Sm have not. All of major and minor elements contents except $K_2O$ and Ba were less than world mean contents of shallow surface sediments but apprehend a high pollution possibility on silt sediments in the estuaries.

• Economic and Environmental Geology
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• v.39 no.3 s.178
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• pp.329-342
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• 2006

The purpose of this study is to determine the geochemical characteristics for the stream sediments in the Konyang area. So we can estimate the environment contamination and understand geochemical disaster. We collect the stream sediments samples by wet sieving along the primary channels and slowly dry the collected samples in the laboratory and grind to pass a 200mesh using an alumina mortar and pestle for chemical analysis. Mineralogy, major, trace and rare earth elements are determined by XRD, XRE, ICP-AES and NAA analysis methods. For geochemical characteristics on the geological groups of stream sediments, the studied area was grouped into quartz porphyry area, sedimentary rock area, anorthosite area and gneiss area. Contents of major elements for the stream sediments in the Konyang area were $SiO_2\;41.86{\sim}76.74\;wt.%,\;Al_{2}O_{3}\;9.92{\sim}30.00\;wt.%,\;Fe_{2}O_{3}\;2.74{\sim}12.68\;wt.%,\;CaO\;0.22{\sim}3.31\;wt.%,\;MgO\;0.34{\sim}3.97\;wt.%,\;K_{2}O\;0.75{\sim}0.93\;wt.%,\;Na_{2}O\;0.25{\sim}1.92\;wt.%,\;TiO_{2}\;0.40{\sim}3.00\;wt.%,\;MnO\;0.03{\sim}0.21\;wt.%,\;P_{2}O_{5}\;0.05{\sim}0.38\;wt.%$. The contents of trace and rare earth elements for the stream sediments were $Cu\;7{\sim}102\;ppm,\;Pb\;15{\sim}47\;ppm,\;Sr\;48{\sim}513\;ppm,\;V\;29{\sim}129\;ppm,\;Zr\;31{\sim}217\;ppm,\;Li\;14{\sim}94\;ppm,\;Co\;5.6{\sim}32.1\;ppm,\;Cr\;23{\sim}259\;ppm,\;Cs\;1.7{\sim}8.7\;ppm,\;Hf\;2.1{\sim}109.0\;ppm,\;Rb\;34{\sim}247\;ppm,\;Sc\;4.5{\sim}21.9\;ppm,\;Zn\;24{\sim}609\;ppm,\;Sb\;0.8{\sim}2.6\;ppm,\;Th\;3{\sim}213\;ppm,\;Ce\;22{\sim}1000\;ppm,\;Eu\;0.7{\sim}5.3\;ppm,\;Yb\;0.6{\sim}6.4\;ppm$. Generally, the contents of $Al_{2}O_{3}\;and\;SiO_2$ had a good relationships with each other in rocks but it had a bad relationships in stream sediments for this study area. The contents of $Fe_{2}O_3$, CaO, MnO and $P_{2}O_{5}$ had a good relationships with major and minor elements in stream sediments of this study area. The contents of Co and V in the stream sediments had a good relationships with other toxic elements.

• Economic and Environmental Geology
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• v.26 no.3
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• pp.337-347
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• 1993

Mineralogical and geochemical studies on some pyrophyllite deposits in Milyang area, Kyeongnam Province (Milyang and Sungjin mine) were carried out in order to investigate dispersion patterns of chemical elements in altered volcanic wallrocks, and to interpret genetic environments of the pyrophyllite deposits. Cretaceous andesitic and tuffaceous rocks, and pyrophyllite ore specimens were collected from the dumps and drilling cores. Andesitic wallrocks were grouped as unaltered and altered rocks in the order of pyrophyllitization. Vertical dispersion patterns and relative mobilities of chemical elements in volcanic wallrocks were discussed. Geochemical environment in the Milyang area is characterized by the occurrence of boron minerals such as dumortierite coexisting with pyrophyllite ores, and tourmaline in granitic rocks. Unaltered andesitic rocks are mainly composed of plagioclase, pyroxene and hornblende, and were propylitized and saussuritized. Altered andesitic rocks are bleached and consist of quartz, sericite, pyrophyllite, kaolinite, chlorite and disseminated pyrite. Pyrophyllite ores are mainly composed of quartz, pyrophyllite, dumortierite, dissemianted pyrite and some diaspore. Enrichment of $SiO_2$, $Al_2O_3$, LOI (loss on ignition), As and Cr, and depletion of $K_2O$, $Na_2O$, CaO, MgO and total Fe are characteristic during alteration process. The REE patterns show that the pyrophyllite deposits could be originated from the continental margin volcanics. The $(La/Lu)_{cn}$ ratios of the pyrophyllite ores increase from 4.2~23.2 to 2.67~128.8 owing to strong acidic hydrothermal alteration. Vertical dispersion patterns of $Al_2O_3$, $K_2O$, $Na_2O$, CaO, MgO, $Fe_2O_3$ (total Fe), As, Au, Sb, Cr and Sr in the wallrocks show the location of orebodies. Particularly dispersion patterns of $Al_2O_3$ and Cr indicate the extension of orebodies. Anomalous distribution of Au, As and Sb in wallrocks shows potential for gold occurrence below the pyrophyllite deposits. Judging from the relative mobilities of elements in wallrocks, $Al_2O_3$ could be added from hydrothermal solution, and the silicified rone be formed from the excess of $SiO_2$.

• Journal of the Korean Ceramic Society
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• v.46 no.4
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• pp.413-418
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• 2009

Glass systems based on Ca, Sr, Ba, and Zn modified alumino-boro silicates were investigated in order to improve the dielectric and mechanical properties of a typical LTCC (low temperature co-fired ceramic) which was developed for high frequency highly-integrated modules. The glass was prepared by a typical melting procedure and then mixed with cordierite fillers to fabricate glass/ceramic composite-type LTCC materials. The amount of cordierite filler was fixed at 50 volumetric%. For an optimal glass composition of 7.5% CaO, 7.5% BaO, 5% ZnO, 10% $Al_2O_3$, 30% $B_2O_3$, and 40% $SiO_2$ in mole ratio, the resultant LTCC composite showed a dielectric constant of 5.8 and a dielectric loss ($tan{\delta}$) of 0.0009 after firing at $900^{\circ}C$. An average bending strength of 160MPa was obtained for the optimal composition.