• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.689-696
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• 2008

The purpose of this study was to evaluate the alkali-silica reactivity for aggregates in Korea according to test methods: accelerated mortar bar test (AMBT) by ASTM C 1260; chemical test by KS F 2545 (ASTM C 289). The results are as follows: The AMBT (ASTM C 1260) results showed that two (2) igneous rocks (two mica granite and felsite), three (3) sedimentary rocks (arkose, red sandstone and shale), two (2) metamorphic rock (slate and vitric tuff), one (1) mineral (quartz) showed more expansion than 0.1% at 14 days. But, some sedimentary rocks and metamorphic rocks expanded more than 0.1% at 28 days even though they were less than 0.1% at 14 days. Therefore, it is necessary to extend the experimental dates more than 14 days to evaluate the possibility of alkali-aggregate reactivity. The chemical test (KS F 2545) results showed that five (5) igneous rocks (andesite, diabase, granite porphyry, muscovite granite and diorite) were indicative of potentially deleterious expansion, while two (2) igneous rocks (diorite porphyry and quartz porphyry) were possible indicative of expansion, and three (3) igneous rocks (biotite granite, two mica granite and felsite) were indicative of innocuous reactivity. The above results showed that the results from chemical method (KS F 2545) and AMBT (ASTM C 1260) had little relationship.

• Journal of Conservation Science
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• v.5 no.1 s.5
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• pp.41-68
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• 1996

Stone-cultural-properties, distributed In the area, have been investigated and studied on the characteristics and the rock phases in the geological and conservational point of view. Stone-Buddhas in the area can be subdivided into Maebul-, General -, and Massive rock-types according to their styles. The rocks used in these stone-cultural-properties are mainly massive, coarse grained biotite granite of the Jurassic age, which is widely distributed around the Reckon-gun area. However, quartz-feldspathic banded gneiss, marble, phyllite and hornblendite are also used. These rocks are mainly distributed in the Yongin-gun area. This suggests that the rocks used. These rocks are strongly influenced by chemical weathering so that the rock surface is very irregular with $2\~3mm$ relief. Biotite granite used shows generally weathered surface of brown color due to chemical weathering of feldspars. Moss are pervasive partly on the surface to show black and/or green colors. The strong weathering may induce secondarily to appear the igneous lineation, onion-structure, and/or minor cracks latent in the rocks. The cultural properties In the area are relatively well conserved except Maebuls and one(Duchangri 3-story) pagoda. However, one stone-buddha may be grinded recently by machine to take off the weathered surface resulting in the loss of its age and the original detailed shape. For conservation, they must be scientifically considered on the shape, kind of the rock phase and characteristics of the weathered phenomena.

• Journal of the Korean Geographical Society
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• v.39 no.6 s.105
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• pp.845-862
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• 2004

The aim of this study is to investigate distribution characteristics of incised meander cutoff in Gyeonggi and Gangwon Provinces of Central Korea. The density of meander cutoff is highest in the mountain rivers including Naerin and Dongdae flowing on Jeongseon-gun and Inje-gun of Gangwon Province. Most of meander cutoff process has been occurred repeatedly during the Quaternary period, especially concentrated in the period of climatic change between glacial and interglacial stages. In the aspect of the lithology, the density of cutoff is highest in sedimentary rock, but lowest in igneous rock. As for geological structure, its frequency is high at $11{\sim}20km$ westerly away from the Taebaek Mountains, at subsequent channel, lower part of resequent channel, and channels crossing the fault line. The relation between distance from the Taebaek Mountains and altitude is very obvious at the western side of the Taebaek Mountains. The values of altitude, height from riverbed, and stream order are highest at sedimentary rock and lowest at volcanic rock.

• Computers and Concrete
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• v.17 no.1
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• pp.129-140
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• 2016

Basalt is a type of volcanic rocks, grey to black in colour, contains less than 20% quartz, 10% feldspathoid, and at least 65% of the feldspar of its volume. Basalt is considered an igneous rock with fine grains due to the rapid cooling of lava. Basaltic rocks have been widely used as aggregate for various purposes. The study presented in this paper was carried out on basalts that are widespread in the Madeira Island of Portugal and that comprise the major source of local crushed rock aggregates. This paper discusses an experimental programme that was carried out to study the effects of basaltic aggregate on the compressive strength and modulus of elasticity of concrete. For this purpose, cylinder specimens with $150{\times}300mm$ dimensions and prism specimens with $150{\times}150{\times}375mm$ dimensions were cast. The experimental programme was carried out with several concrete compositions belonging to strength classes C20/25, C25/30, C30/37, C40/50 and C60/75. The Eurocode 2 indicates the modulus of elasticity should be 20% higher when the aggregates are of basaltic origin, however results showed significant differences and a correction is proposed.

• Economic and Environmental Geology
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• v.17 no.2
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• pp.91-100
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• 1984

The Gwangyang gold deposits geologically consist of granitic gneiss, metatectic gneiss and porphyroblastic gneiss which correspond to Jirisan gneiss complex. The formations of Gyeongsang system lies unconformably on these gneisses and are intruded by diorite, porphyritic andesite and Bulgugsa granites. Goheung districts are composed of quartz schist, andesitic rock, tuff and granite. The Gwangyang gold deposits are gold bearing fissure filling veins. The vein thickness varies from 15cm to 40cm and they consist of 7-10 layers in parallel. The Goheung copper deposits are sulphide bearing quartz veln which filled the fracture in andesitic rock and biotite granite. The contact zone of these rocks is partially altered. The mineral paragenesis of the Gwangyang and Goheung districts is pyrite, arsenopyrite, pyrrhotite, chalcopyrite, sphalerite, galena, sericite, quartz and calcite. The variation trends of FMA and A'KF triangular diagrams and the differentiation index (norm, Q + Or + Ab) versus oxides diagrams is similar to the Gyeonsang basin igneous rocks. From the trace element analysis of 10 samples of country rocks, wall rocks and veins, the distribution of copper and lead contents display a correlative distribution pattern in relation to gold and silver. Homogenization temperature of fluid inclusions range from $200^{\circ}C$ to $270^{\circ}C$ in quartz from the Gwangyang gold vein and the size of fluid inclusion range from 0.01mm to 0.04mm. The fluid inclusions are mainly one or two phase and the filling degree of the inclusions varies from 85 to 95.

• Journal of the Korean GEO-environmental Society
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• v.7 no.2
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• pp.33-42
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• 2006

Eighteen biotite granites on Andong area and twenty seven igneous rocks(diorite, granite, andesite, rhyolite) on Yeosu area were tested to evaluate the correlations between the uniaxial compressive strength values, as determined by the standard uniaxial compression test, and the corresponding results of the ultrasonic velocity. The variability of test results for each test was evaluated by calculating the coefficient of determination or variation. Results indicate that strong correlations exist between the results of uniaxial compression vs the point load, Schmidt hammer and ultrasonic velocity test. The correlation equations for predicting compressive strength using different methods are presented along with their confidence limits. Ultrasonic velocity test used provide reliable estimates of compressive strength.

• Economic and Environmental Geology
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• v.21 no.4
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• pp.349-358
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• 1988

K-Ar ages were determined on gangue and wall rock alteration minerals from twenty metallic mineral deposits in the Gyeonggi Massif. Beryl deposits give the age of 185 Ma, whereas tungsten - molybdenum deposits reveal two different age groups such as 172~156 Ma and 91~86Ma. Lead - zinc deposits and gold - silver deposits yield the ages of 160 Ma and 71~197 Ma, respectively. Mineralization ages for each genetic type of deposits in the Gyeonggi Massif can be summarized as follows; pegmatite deposits, 185 Ma; skarn deposits, 156~160 Ma; hydrothermal deposits, 71~197 Ma. Present results together with data previously reported reveal that rare earths, tungsten-molybdenum, base and precious metal deposits in the Gyeonggi Massif were formed in Jurassic and Cretaceous time with a genetic relationship to the Daebo and Bulguksa felsic igneous activity.

• Economic and Environmental Geology
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• v.2 no.2
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• pp.73-75
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• 1969

Ogbang scheelite deposit imbedded in amphibolite of unknown age was believed, by the previous workers, to be of pegmatite vein. The vein material is composed mainly of plagioclase (albite and oligoclase) and minor amount (less than 5 to 10% each) of hornblende, biotite and quartz. Orthoclose and tourmaline are accompanied in few places and scheelite and minor amount of fluorite, are the ore minerals. On the basis of mineralogical constituents of the vein, vein structures, mode of occurrence of the vein and gradational contact between veins and amphibolite, the present writer conclude that the deposit was formed by segregation from the parent basic igneous rock of amphibolite. The main portions of the deposit were formed by intrusion of ore solution into already solidified amphibolite after being segregated in deeper horizone, whereas the minor portion by segregation of ore solution in situ.

• Economic and Environmental Geology
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• v.18 no.1
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• pp.11-22
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• 1985

The Daehwa and Donsan tungsten-molybdenum deposits are composed of numerous fissure-filling veins developed in Precambrian gneiss and Cretaceous granite and quartz porphyry. K-Ar age of biotite in granite and that of muscovite in ore veins are $105{\pm}5\;Ma$ and 88.2~88.6 Ma respectively. Occurrence of ore deposits shows that relevant igneous rock is possibly quartz porphyry rather than above mentioned granite in temporal view point. Vein structure and mineralogy suggest that ore veins were formed by continuous vein filling, not by repeated mineralization. Three distinct depositional stages with decreasing age can be devided on the basis of mineral paragenesis and fluid inclusion studies: Stage I, deposition of oxides and silicates; stage II, deposition of base-metal sulfides and sulfosalts with carbonates; stage III, deposition of barren calcite and fluorite. Tungsten, molybdenum and tin mineralization occurred in stage I.

• Journal of Conservation Science
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• v.1 no.1 s.1
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• pp.40-59
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• 1992

Stone-monuments, distributed in this area, have been investigated and studied in geological and conservational points of view. They are seemed to have been built from the Shilla to Koryeo Kingdoms, although more systematic studies are needed. The used rocks in these monuments are mainly biotite granite of Jurassic age. They are strongly weathered and partly exfoliated along igneous lineation about 1-2 mm(maximum up to 5 mm). They are mainly effected by chemical weathering to be selectively dissolved and by various kind of moss. For conservation, it must be scientifically considered based on characteristics and kind of rock phase, factors on weathering process, situation and protection.