• Proceedings of the Petrological Society of Korea Conference
• /
• 2009.05a
• /
• pp.66-68
• /
• 2009

• Geotechnical Engineering
• /
• v.9 no.3
• /
• pp.5-22
• /
• 1993

A series of laboratory tests (physical and mechanical index and engineering design) were conducted on undisturbed granite soils of CW and RS weathering grades in Korea. From these testes it can be concluded that most of physical and mechanical index values are very sensitive to change in weathering grade from CW to RS. Engineering design tests indicate that the unconfined compressive strength and the shear strength parameters are significantly reduced and that the soil becomes ductile and plastic with increasing weathering and saturation. It was found that weathered granite soils have the special characteristics when water saturated: (i) they significantly lose their shear strength(especially cohesion) and unconfined compressive strength, (ii) they are fragile and their grains break down in water as observed in grain size analysis.

• Economic and Environmental Geology
• /
• v.45 no.5
• /
• pp.535-549
• /
• 2012

Main aspect of this study are to clarify mineral compositions on granites in Youngkwang-Naju area. These granites are is divided into four rock facies based on the geologic ages, mineralogical composition and chemical constituents, and texture : hornblende-biotite granodiorite, biotite granite, porphyritic granite and two mica granite. These granites constitude an igneous complex formed by a series of differentiation from cogenetic magma. In compressive stress field between the Ogcheon folded belt and the Youngnam massif, the foliated and undeformed granites had formed owing to heterogeneous distribution of stress. The geochemical data of study area indicate magma of these rocks would had been generated by melting in lower and middle crust. The major minerals of granitic rocks in study area are plagioclase, biotite, muscovite and hornblende. Plagioclase range in composition from oligoclase ($An_{19.3-27.7}$) to andesine ($An_{28.4-31}$), and shows normal zoning patterns, This uniformed composition indicated slow crystallization, and it is obvious that the growth of these crystal occurred before final consolidation of the magma. The Mg content of biotite are increases with increasing of $f_{O2}$ and grade of differentiation, changing from phlogopite to siderophyllite. Its $Al^{iv}$/$Al^{total}$ ratios are propertional to bulk rock alumina content. Muscovite is primary in origin with high content of $TiO_2$, and Its composition correspond to celadonitic muscovite. Hornblende indicated calc amphibole group ($(Ca+Na)_{M4}{\geq}1.43$, $Na_{M4}<0.67$). and consolidation pressure of granitic body by geobarometer of Hammerstrume and Zen show 11.3~17.2 Km.

• Economic and Environmental Geology
• /
• v.41 no.3
• /
• pp.299-314
• /
• 2008

The NE-trending Honam shear zone is a broad, dextral strike-slip fault zone between the southern margin of the Okcheon Belt and the Precambrian Yeongnam Massif in South Korea and is parallel to the trend of Sinian deformation that is conspicuous in Far East Asia. In this paper, we report geochemical and isotopic(Sr and Nd) data of mylonitic quartz-muscovite Precambrian gneisses and surrounding foliated hornblende-biotite granitoids near the Myeongho area in the Yecheon Shear Zone, a representative segment of the Honam Shear Zone. Foliated hornblende-biotite granitoids commonly plot in the granodiorite field($SiO_2=61.9-67.1\;wt%$ and $Na_2O+K_2O=5.21-6.99\;wt%$) on $SiO_2$ vs. $Na_2O+K_2O$ discrimination diagram, whereas quartz-muscovite Precambrian orthogneisses plot in the granite field. The foliated hornblende-biotite granitoids are mostly calcic and calc-alkalic and are dominantly magnesian in a modified alkali-lime index(MALI) and Fe# [$=FeO_{total}(FeO_{total}+MgO)$] versus $SiO_2$ diagrams, which correspond with geochemical characteristics of Cordilleran Mesozoic batholiths. The foliated hornblende-biotite granitoids have molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 0.89 to 1.10 and are metaluminous to weakly peraluminous, indicating I type. In contrast, Paleoproterozoic orthogneisses have peraluminous compositions, with molar ratios of $Al_2O_3/(CaO+Na_2O+K_2O)$ ranging from 1.11 to 1.22. On trace element spider diagrams normalized to the primitive mantle, the large ion lithophile element(LILE) enrichments(Rb, Ba, Th and U) and negative Ta-Nb-P-Ti anomalies of foliated hornblende-biotite granitoids and mylonitized quartz-muscovite gneisses in the Yecheon Shear Zone are features common to subduction-related granitoids and are also found in granitoids from a crustal source derived from the arc crust of active continental margin. ${\varepsilon}_{Nd}(T)$ and initial Sr-ratio ratios of foliated hornblende-biotite granitoids with suggest the involvement of upper crust-derived melts in granitoid petrogenesis. Foliated hornblende-biotite granitoids in the study area, together with the Yeongju Batholith, show not changing contents of specific elements(Ti, P, Zr, V and Y) from shear zone to the area near the shear zone. These results suggest that no volume changes and geochemical alterations in fluid-rich foliated hornblende-biotite granitoids may occur during deformation, which mass transfer by fluid flow into the shear zone is equal to the mass transfer out of the shear zone.

• Economic and Environmental Geology
• /
• v.34 no.1
• /
• pp.55-70
• /
• 2001

Granitoids in the Younggwang-Kimje area can be divided into two types of granite. One is foliated granite (Cheongup and Kochang foliated granites) developed along the NE-SW direction kwangju fault system and the other is undeformed granite (Kimje and Younggwang granites) developed in the western part of the area. $SiO_2$ content of study area, Younggwang granite is 62.8-74.0%, Kochang foliated granite is 64.5-74.4%, Cheongup foliated granite is 64.5-70.2%, Kimje granite is 63.4-72.0%. The result indicated that these granitoids belong to the intermediate and acidic rock. In Harker's diagram, as $SiO_2$ increases, $Al_2O_3$, $Fe_2O_3$, MgO, CaO, $TiO_2$> $P_2O_{5}$s and MnO decrease, but $K_2O$ increases. In AFM diagram, Younggwang granite, Kochang foliated granite, Cheongup foliated granite and Kimje granite belong to calk-alkaline rock series. And in triangular diagrams of normative Qz-Or-Pl and An-Ab-Or, they are located in granodiorite and granite region. On the co-variation diagrams of trace elements with silica, Ba, Co, Li, Nb, An, Rb elements show increasing patterns. The diagrams of ACF and $Na_2O$ vs. $K_2O$ ratios indicate that granitoids of the study area belong to I-type.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.5
• /
• pp.1754-1759
• /
• 2010

Because the stone cultural properties located outdoors, they have been altered and deteriorated in external appearance due to environmental factors such as acid rain, extreme change in temperature, and salts. Damage to stone cultural properties is accelerated particularly due to recent industrial development and environmental pollution. An experimental study was conducted to evaluate the effect of environmental contaminants(sea water and air pollutants such as, $SO_2$, NO, $CO_2$) on the weathering of granite. And as part of the developing of conservation method, $TiO_2$ catalyst was prepared and tested. After expose a granite to sea water and air pollutants, the mineral compositions of the tested granite surface were lower then that of the fresh granite. And absorption capacity of the weathered granite was steadily increased. From these results, it was expected that granite could be weathered by sea water and air pollutants. For the $TiO_2$ coated granite, absorption capacity was slightly enhanced compared to the $TiO_2$ non-coated granite. Therefore, the $TiO_2$ coating method tested in this study considered to be a viable method to assist in the conservation of granite from environmental contaminants.

• Tunnel and Underground Space
• /
• v.20 no.5
• /
• pp.390-398
• /
• 2010

The time-dependent behaviour of rock is very important characteristics which can be utilized as basic input data for underground mine design or in predicting a long-term stability of underground rock mass structures. In this study, creep tests under uniaxial compression were carried out for the granite specimens sampled in Gagok Mine. Burgers model, Griggs and Singh creep laws were used to simulate the measured creep strain. Through comparing the measured creep behaviour with the approximated creep behaviors from Burgers model, Griggs and Singh creep laws, it is shown that Griggs creep law results in the best approximation of granite in Gagok Mine.

• The Journal of Engineering Geology
• /
• v.22 no.2
• /
• pp.173-183
• /
• 2012

The nature of surface deformation of Tono granite was investigated using a confocal laser scanning microscope (CLSM) under water-saturated stress relaxation conditions. A new apparatus was developed for this experiment, enabling continuous measurements of stress-strain and simultaneous observations of surface deformation by CLSM. The amounts of grain contact deformation and intra-granular surface deformation were calculated using a finite element method. The results reveal that intense grain contact deformation and intra-granular surface deformation occurred during the period of stress relaxation, and that the intensity of this deformation increased with increasing applied stress. Finite element method (FEM) results show that the strain of grain boundary was greater than strain of inter-granular surface. Contour maps of these local strains were compiled for individual grains and their boundaries, revealing intense deformation at the boundaries between biotite and quartz under compressional stress. This result was a consequence of the mechano-chemical effect of biotite and quartz minerals. Biotite in granite has a layered structure of iron-magnesium-aluminum silicate sheets that are weakly bonded together by layers of potassium ions. In contrast, quartz occurs as stable spherical grains.

• The Journal of the Petrological Society of Korea
• /
• v.22 no.2
• /
• pp.197-208
• /
• 2013

The Namwon and Sunchang granites are neighbouring plutons intruding the Yeongnam massif and the Okcheon metamorphic belt, respectively in the southwestern part of the Korean peninsula. In this study, SHRIMP zircon U-Pb ages are determined from these plutons. The results show that the emplacement age of the Namwon granite is $185.8{\pm}0.9(2{\sigma})$ Ma. We obtained $175.0{\pm}2.0(2{\sigma})$ Ma from the northern part and $179.8{\pm}0.9(2{\sigma})$ Ma from the central part of the Sunchang granite, yielding $177.4{\pm}1.3(2{\sigma})$ Ma as the average age of the pluton. Such age results confirm that the Honam shear zone, which cause marked deformation of the Sunchang granite, was active after ca. 175 Ma.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.8
• /
• pp.2026-2031
• /
• 2009

Because the stone cultural properties located outdoors, they have been altered and deteriorated in external appearance due to environmental factors. Damage to stone cultural properties is accelerated particularly due to recent industrial development and environmental pollution. When fresh granite was dipped into the seawater, the mineral compositions(Ca, K) of the granite surface were lower then those of the fresh granite and density of the weathered granite was steadily decreased from $2.600 g/cm^3$ to $2.580-2.582 g/cm^3$. Also, absorption capacity of the weathered granite was steadily increased from 0.392% to $0.526{\sim}0.616%$. In the case of $TiO_2$ was coated to the granite, the change of density and absorption ratio of $TiO_2$ coated granite were decreased. Therefore, the $TiO_2$ coating considered to be a viable method to assist in the conservation of stone cultural properties from environmental contaminants.