• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.431-445
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• 2022

A quantitative phase analysis method of X-ray powder diffraction was studied to determine the mineral content of clay-rich rocks practically as well as effectively. For quantitative X-ray powder diffraction analysis of the clay-rich rocks, it is necessary to prepare whole-rock powder samples with a random orientation by side mounting method. In addition, for the identification of the clay minerals in the rock, it is required to prepare an oriented mount specimen with a clay particle size of 2 ㎛ or less, ethylene glycol treatment, and heat treatment. RIR (reference intensity ratio) and Rietveld method were used for the quantitative analysis of the clay-rich rocks. It was possible to obtain the total clay and the non-clay minerals contents from the whole-rock X-ray diffraction profiles using the RIR values. In addition, it was possible to calculate the relative content of each clay mineral from the oriented X-ray diffraction profiles of the clay particle size and assign it to the total clay. In the Rietveld method of whole-rock X-ray diffraction, effective quantitative values were obtained from the Rietveld diffraction patterns excluded the region of less than 10 degrees (2θ). Similar quantitative values were shown in not only the RIR but the Rietveld methods. Therefore, the analysis results indicate a possibility of a routine quantitative analysis of clay-rich rocks in the laboratory. However, quantitative analysis of clay minerals is still a challenge because there are numerous varieties of clay minerals with different chemical and structural characteristics.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.582-590
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• 1995

우리 나라에서 건설될 중저준위폐기물 처분장의 기본설계개념에 따르면, 중준위폐기물 동굴에는 점토질 뒷채움재가 설치될 예정이다. 이 뒷채움재의 후보물질로는 원료 입수의 용이성 및 경제성 측면에서 천연점토와 분쇄암석의 혼합물이 고려되고 있다. 그러나 이 혼합물이 폐기물처분장의 뒷채움재로 사용되기 위해서는 주요특성들이 뒷채움재의 요구사항을 만족시켜야한다. 이 보고서에서는 경상북도 연일지역에서 산출되는 천연점토와 분쇄암석 혼합물에 대해 핵종유출저지 관점에서 가장 중요한 특성인 수리특성과 방사성핵종 확산특성 및 역학적 특성을 측정하여 뒷채움재료로서의 사용 가능성을 평가하였다. 혼합물의 수리전도도는 동일 밀도에서 점토함량이 감소함에 따라 증가되었으나, 점토함량이 적은 경우에도 상당히 낮은 값을 유지하여 뒷채움재를 통한 핵종이동의 주요 메커니즘은 확산이 될 것이라는 것을 보여주었다. 압축점토에 대한 방사성핵종 복산계수 측정결과, 동일밀도의 나트륨벤토나이트에서 측정된 값의 범위 내에 있었으며, 점토-분쇄암석 혼합물의 액소성한계, 다짐특성, 압축강도및 압밀계수등의 역학적 특성도 나트륨벤토나이트-모래 혼합물에서 얻어진 값과 유사하였다. 이러한 결과들로부터 연일산 천연점토-분채암석 혼합물을 고가의 나트륨벤토나이트 대용으로 처분장 뒷채움재로 사용할 수 있다는 것을 알 수 있었다.

• The Journal of the Petrological Society of Korea
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• v.17 no.3
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• pp.133-143
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• 2008

On the basis of chemical composition of granite, gneiss and their weathering products, in this paper, rare earth elements (REEs) was estimated as tracer for clarifying a geochemical variance of earth surface material during weathering process. The chemical composition of clay, clay ware and pottery also were measured for testifying usefulness of REE geochemistry in clarifying the source material of pottery. It was observed that there was no systematic variation of chemical composition among source rock, weathered rock and soil during weathering process. The chemical composition of clay, clay ware and pottery also did not show systematic variation by baking pottery. However, PAAS (Post Archean Australian Shale)-normalized REE patterns of rock-weathered rock-soil and clay-clay ware-pottery are similar regardless of weathering process or ceramic art. Our results confirm that REE geochemistry is powerful tool for clarifying the source materials of surface sediment or archaeological ceramic products.

• Proceedings of the Petrological Society of Korea Conference
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• 2001.06a
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• pp.16-22
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• 2001

• Korean Journal of Crystallography
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• v.1 no.1
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• pp.35-48
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• 1990

본 연구에서는 포항-연일지역 및 감포-하서지 역의 점토광물과 주변모암의 열괭창 특성, 지구화 학적 및 물리적 특성. 그리고 성인에 대하여 고찰하였다. Ca계 몬모릴로나이트영역에 속함을 알 수 있다. 그러나 제올라이트는 뚜렷한 특징을 보이지 않는다. 점토질암석과 그 이외의 벤토나이트 및 제올라이트사이의 Sr. Cu, V. Li과 La의 함량에는 차이가 발견된다.

• The Journal of the Petrological Society of Korea
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• v.1 no.1
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• pp.58-70
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• 1992

From the K-Ar age determinations for the clay deposits and their surrounded rocks in southwest Korea, the ages of the ore formation in all clay deposits fall in very narrow range from 78.1 to 81.4 Ma. K-Ar ages of clay deposits are slightly younger than those of the Cretaceous volcanic rocks (Hwangsan Formation, 81.4 to 86.4 Ma) and are slightly older than those of the Cretaceous granitic rocks (77.1 to 81.5 Ma). These results indicate that clay deposits were formed with genetical relation to late Cretaceous felsic magmatism. Weolgagsan granite, which has been previously considered to be Cretaceous, is proved to be formed its age in Jurassic (140.9 and 144.8 Ma). The close relationships of K-Ar ages between the clay deposits and Cretaceous granitic rocks suggest that the clay deposits were formed during the hydrothermal alterations caused by the thermal effects (hydrothermal circulation) of the granitic intrusions rather than by the hydrothermal activities associated with volcanic activities.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.3
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• pp.153-163
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• 2020

Mineral and geochemical analysis were conducted on two sections (~3.5 m) of red-brown claysilt sediments covering the gneiss and granite weathering zones in Suwon-si for establishing Quaternary paleoenvironmental changes in Korea. The sections were divided into four sedimentary layers (Unit 1-4) by vertical changes in mineral composition and chemical composition. The lowermost unit 1 was a sandy sediment with a high K-feldspar content with a significant contribution of weathered bedrock. Unit 2 was a transition layer showing intermediate characteristics. Unit 3 was a reddish brown clay-silt sediment, with a total clay content of 58% on average, and the main clay minerals were illite-smectite mixed layer minerals and hydroxy-interlayered vermiculite/smectite. Unit 3 contained almost no plagioclase, while the content of kaolin minerals derived by the plagioclase weathering was higher than in the other layers. Unit 4 had similar mineral composition and chemical properties to Unit 3, but had a higher content of plagioclase and chlorite and lower content of kaolin minerals. The chemical compositions of the sections were compared with those in other regions of Korea, suggesting the eolian origin of Units 3 and 4. The paleoenvironmental change in the sedimentary section of this region was interpreted as follows. Weathered products of gneiss and granite, which are bedrocks of this region, were eroded and deposited as sandy sediments in the periphery to form the lower layers (Unit 1, 2), followed by the deposition of the claysilty rich eolian sediments (Unit 3) during the glacial. Unit 3 was chemically weathered during the warm humid climate during the last interglacial, developing a reddish brown color. After that, a eolian sediment layer (Unit 4) was deposited during the last glacial.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.4
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• pp.397-407
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• 2022

Mineralogical analysis of the bedrock of the Gobi Desert in southern Mongolia, the source of Asian dust, was conducted to trace the geological origin of the constituent minerals of Asian dust. The bedrock of the source of Asian dust consists of Paleozoic volcanics and volcaniclastic sedimentary rocks, Paleozoic granitic rocks, and Mesozoic sedimentary rocks. Paleozoic volcanics and volcaniclastic sediments lithified compactly, underwent greenschist metamorphism, and deformed to form mountain ranges. Mesozoic sedimentary rocks fill the basin between the mountain ranges of Paleozoic strata. In comparison to Paleozoic volcanic and sedimentary rocks, Mesozoic sedimentary rocks have lower contents of chlorite and plagioclase, but high contents of clay minerals including interstratified illite-smectite, smectite, and kaolinite. Paleozoic granites characteristically contain amphibole and biotite. Compared with the mineral composition of bedrock in source, Asian dust is a mixture of detrital particles originating from Paleozoic and Mesozoic bedrocks. However, the mineral composition of Mesozoic sedimentary rocks is closer to that of Asian dust. Less lithified Mesozoic sedimentary rocks easily disintegrated to form silty soils which are deflated to form Asian dust.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.10a
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• pp.239-246
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• 2005

slaking 은 굴착에 의해 노출된 암반에서 발생하는 강도저하 및 입자간의 결합력 약화에 의해 암반이 세립화하는 현상이다. 이러한 slaking은 특히 퇴적암으로 구성된 암반사변의 안정성에 영향을 미치는 중요한 인자로 작용한다. slaking에 의한 암반사면의 불안정성은 신생대의 이질암이나 미고결 응회암에서와 같이 암반 자체의 강도 저하 및 결합력 약화에 의해 발생하는 붕괴현상과 차별풍화에 의해 이암 등이 급속도로 쇄굴 및 풍화되어 상부에 놓여 있는 암석이 낙석 등의 형태로 붕괴되는 현상으로 구분할 수 있다. 본 연구에서는 이암의 차별풍화에 의해 사면의 불안정성이 유발되는 연구지역을 대상으로 풍화 및 쇄굴 속도와 slake의 상관관계를 밝히고자하였다. 이를 위하여 slake test와 slake durability test를 수행하였으며 slake durability index를 획득하였다. 실험을 통해 획득된 slake durability index를 연간 쇄굴속도와 비교하여 상관관계를 검토하였으며 기존의 연구결과와 비교하여 slake durability index를 활용하여 쇄굴 정도를 예측할 수 있는 가능성을 제시하였다.

• Economic and Environmental Geology
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• v.53 no.1
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• pp.87-98
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• 2020

The bird track fossil site in Haman Formation is divided into seven sedimental layers by the sedimentary structures, lithofacies and sequences. The bird tracks top on the highest layer, which includes ripple marks and suncracks. The layer has lithofacies with reddish grey siltstone and dark grey mudstone, alternately. As an analysis for the same rocks of the fossil site, physical properties show on mean values for 0.62% of absorption rate, 1.64% of porosity and 2.63 of specific gravity. Rock-forming minerals composed mainly of plagioclase, quartz, calcite, chlorite and mica. Meanwhile, we executed an experiments based on the petrography and weatherings to find a proper consolidants. In the experiments, the OH 100 reagent proved stable aspect and the lowest transition rate in terms of weight and chromaticity. Also, it showed the highest increase in ultrasonic velocity, improving the physical properties of the rocks. In the case of applying the OH 100 with antihygro, an swelling inhibitors on the sedimentary rocks, the chromaticity indicated an stable transition aspect. When it comes to the physical properties, the antihygro also decreases the porosity effectively. Thus, the most proper method for the fossil site of Haman Formation is to apply antihygro and OH 100 reagents since the rocks includes clay minerals that show swelling characteristics. However, this result is deduced from an indoor application experiments, leaving the necessity of verification how these reagents would affect the bird tracks site under the field condition.