• Journal of the Mineralogical Society of Korea
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• v.17 no.1
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• pp.23-35
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• 2004

The weathering characteristics of periodically submerged sedimentary rocks in the Sayeon dam, Ulsan was examined by field work, electron probe micro-analysis, X-ray diffraction, and X-ray fluorescence spectrometry. Analysis of fracture zone and exfoliation showed the submerged sedimentary rocks have undergone severe mechanical weathering. Mechanical weathering in the water-rock interface accelerated chemical weathering, such as dissolution and alteration of the most of minerals except for quartz in the weathering zone. The dissolution of carbonates specially calcite, is remarkable creating the cavities, whereas formation of minerals including clay minerals is not active. The sedimentary rocks have been periodically submerged for a certain period of time, and have repeated freezing and thawing. This mechanical weathering favored infiltration, which accelerated mineral dissolution. The high content of easily soluble carbonate of the sedimentary rocks is likely the major cause of intense chemical weathering. The dissolved elements within the infiltrated water interrupted the occurrence of clay and weathering minerals, and expend fractures by infiltrated water accelerated weathering process.

• Journal of the Mineralogical Society of Korea
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• v.21 no.4
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• pp.331-339
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• 2008

In the upstream of Nakdong river in Bonghwa-gun, Gyeongsangbuk-do, certain areas of riverside were found to be covered by weathered mine tailings which were assumed to be migrated and deposited by flood. This study was conducted to investigate the formation and characteristics of the secondary minerals from tailings and related leaching behavior of heavy metals in the severely weathered tailing deposits by river waters. Quartz, feldspar, micas, chlorite, hornblende, talc, pyroxene (johannsenite), pyrite, and calcite were identified as primary minerals by XRD. Kaolinite can be formed by the weathering of tailings, but considering the short period of weathering time, kaolinite in the deposits is considered to be from unweathered tailings or moved from soils. The secondary minerals such as goethite, gypsum, basanite, and jarosite were also identified. The formation of the secondary minerals was affected by the species of primary minerals and pH conditions. The weathering of pyrite produced sulfate minerals such as gypsum, basanite, jarosite, and also goethite. Mn oxide was also identified by SEM, coated on the primary minerals such as quartz. This Mn oxide was poorly crystalline and thought to be the weathering product of johannsenite (Mn-pyroxene). The Fe and Mn oxides are the main minerals determining the brown/red and black colors of weathered tailings. EDS results showed that those oxides contain high concentrations of Pb, Zn, and As, indicating that, in the river, the formation of Fe and Mn oxides can control the behavior and leaching of heavy metals by co-precipitation or adsorption.

• Proceedings of the Speleological Society Conference
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• 2005.11a
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• pp.18-32
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• 2005

용신작용에 의한 지형변화에서 지하공간속의 요새화기법을 석회동굴에서 찾아볼 수 있듯이, 여러가지 자연현상 중에서 풍화작용을 같은 원인적 현상에 의한 변형을 통하여 오랜 세월속의 지형지물의 변화에서 나마(gnamma/가마솥바위), 타포니(tafoni/벌집바위) 등의 풍화혈(風化穴/weathering pits)과 같은 기이한 지형물들을 만나볼 수 있다, 특히 우리나라는 대륙에 이어진 반도국가로서 해양성기후권의 해안에서의 해식이나 파식 현상으로 인한 해식애와 파식대 및 해식동굴 등 지형물의 특이한 변화현상이 두드러져 나타나 발견되고 있다. 본 논문은 우리나라 곳곳에 분산되어있는 자연속의 여러 가지 변형지물들을 고찰하기 위하여 먼저 풍화작용과 그 풍화물들에 대한 특이한 지형의 성인과 특징 분석을 통하여 현존 상태의 지형미학적 측면을 비교 관찰하고, 자연의 아름다움과 현경의 중요성을 새롭게 인식하면서 우리의 역할과 가치의 의미를 재조명해보는 현지탐사 활동과 자료조사의 일부이다.

• Journal of The Geomorphological Association of Korea
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• v.19 no.4
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• pp.123-137
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• 2012

Reddish superficial materials in southern area of Korean Peninsula have been defined as lateritic red soil in Korea. In A-CN-K ternary plots, CaO and $Na_2O$ show similar linear distribution along a A-K line to kaolinite profile and laterite in southern Spain and Cameroon, respectively, and it means strong alteration. But $K_2O$ is weak alteration, plotting between muscovite and illite zone. Granitic reddish weathering mantles in study area show bulk distribution in center when plotted in A-CNK-Fm space, in contrast to laterite in Cameroon, plotting linearly in the middle along a A-FM line. Therefore, alteration of reddish saprolites in Southern Korea have not progressed as much as laterite. To define Reddish saprolite in southern Korean Peninsula as a lateritic red soil, more many studies are necessary.

• 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.

• Proceedings of the KGS Conference
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• 2003.05a
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• pp.46-50
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• 2003

하안단구면을 이루는 퇴적층에 포함되어 있는 퇴적물들은 하안단구가 형성된 시기부터 현재까지 풍화를 받게 된다. 즉, 하안단구 퇴적층의 풍화 기간은 바로 하안단구면의 형성시기부터 현재까지가 되는 것이다 외국의 선행 연구들을 통해 볼 때, 암석의 풍화는 초기에 빠르게 진행되지만, 어느 정도 풍화가 진전되면 풍화의 속도가 점차 늦어진다고 제시되고 있으며, 암석과 토양을 구성하고 있는 풍화에 약한 몇 가지 광물들의 존재 유무와 원소 함량의 변화는 풍화 시간과 매우 긍정적인 상관 관계가 있는 것으로 나타난다. (중략)

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.57-60
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• 2003

광업활동이 중지된 후 적절한 조치없이 방치된 폐광석들은 보다 빠르게 풍화될 수 있는 환경에 접하게 된다. 황화광물이 풍화되면 중금속이 용해되어 주변의 지표수나 지하수 및 토양의 오염을 초래한다. 용해된 중금속 이온들은 물리화학적 환경변화가 야기되면 보다 안정한 상태로 침전, 공침 또는 흡착되어지게 될 것이다. 만약 침전된 2차광물들이 불용성 광물이거나, 산성환경에서 비교적 안정한 광물에 흡착되어 제거된 중금속이라면 자연적으로 발생하고 있는 화학반응을 통하여 자연정화가 일어난다고 할 수 있다. (중략)

• Tunnel and Underground Space
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• v.15 no.6 s.59
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• pp.411-424
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• 2005

Weathering is defined as a process by which surface rock, once formed in the deep ground, is broken down and altered to keep the equilibrium with the ambient environment. In this study granitic rock samples of different weathering grades were collected in the field and the microscopic observation, X-ray diffraction analysis, electron microscopic observation, chemical analysis, and rock property tests were carried out. Formation of secondary minerals, especially clay minerals, by weathering was identified and the mechanism for the change of engineering properties such as rock strength degradation was analyzed. Tunnel model test, Failure behaviour, Shallow tunnel, Unsupproted tunnel length.

• Journal of the Mineralogical Society of Korea
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• v.30 no.1
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• pp.11-19
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• 2017

Reddish brown clay-silt sediments covered granitoid weathering crust in the Jangdongri area, Naju, Korea. Mineralogical and geochemical properties of the ~2 m sediment section were investigated. The sediments were composed mainly of quartz (50%) and clay minerals (45%) with minor contents of K-feldspar, goethite, hematite, and gibbsite. The clay minerals were illite, illite-smectite mixed-layers, vermiculite, hydroxy-Al vermiculite, kaolinite, and halloysite. Mineral composition varied little through the section with the minor upward enrichment of plagioclase and chlorite. Abundant illitic clay minerals indicated the remote source of the sediments because clays derived by granite weathering in Korea were dominated by kaolin minerals. A comparison with the mineral composition of Asian dust (Hwangsa) suggested that plagioclase and K-feldspar disappeared by chemical weathering after deposition, resulting in the quartz and clay-rich sediments. Plagioclase and chlorite altered to kaolin and vermiculite, respectively. Goethite and hematite derived by the weathering of iron-bearing minerals stained the sediment to reddish brown color. The mineralogical and geochemical properties of the reddish brown clay-silt sediments were consistent with those of eolian deposits identified in Korea, supporting eolian origin of the Jangdongri sediments, requiring future confirmation including age dating and isotopic analysis.

• 한국문화재보존과학회:학술대회논문집
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• 2004.03a
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• pp.78-91
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• 2004

염(Salts)은 일반적으로 가장 강력한 풍화요인 물질 중 하나이다. 염의 결정화(crystallization) 및 수화(hydration)작용은 석재의 화학적 풍화 뿐만이 아니라 물리적 풍화를 가속화 시킨다. 감은사지 석탑은 오랜 세월 대기 중에 노출되어 대기환경오염으로 인한 화학적 풍화 뿐만이 아니라 지리적으로 바다에 인접해 있어 바다에서 기원한 염화나트륨(NaCl)의 영향으로 다른 석조물에 비해 심한 물리적 풍화현상을 보이고 있다. 편광 현미경 및 SEM, XRD, XRF를 이용하여 석탑의 구성석재 및 염(salts)에 대한분석을 실시하였으며, 용출실험을 통해 얻은 용액에 대해서는 IC와 ICP-AES를 이용하여 분석하였고, 염류와 석재의 반응산물로 만들어진 염에 대해서는 정방위시료와 부정방위시료를 제작하여 분석하였다. 감은사지 석탑을 이루는 암석은 결정응회암으로 주 구성 광물은 사장석 및 정장석이며 소량의 석영 및 흑운모 등이 함유되어 있고 소량의 유리질 석기로 구성되어 있다. 석재의 표면에는 주 구성 광물들의 화학적 풍화로 인해서 생성된 2차 광물로 팽창성 점토광물인 스멕타이트가 존재하며, 대기오염물질과의 결합에 의해 생성된 대표적인 황산염인 석고$(gypsum,\;CaSO_4{\cdot}2H_2O)$, 소금(halite, NaCl), 해양기원 염류인 소금성분과 대기오염물질이 만들어낸 테나다이트$(thenardite,\;Na_2SO_4)$가 존재한다. 이들 염류는 일차적으로 암석의 표면에 백화현상을 초래하기도 하고, 대기 중의 오염물질과 결합하여 일부는 흑화현상을 보이기도 한다. 또한 암석 내 수분이 증가할 경우 이들 염들이 암석의 공극이나 열극을 따라 내부로 이동하여 subflorescence를 발생시켜 박락 및 박탈의 원인이 되었으며, 온도와 수분의 변화에 따른 이들 염(salts)의 수화 및 결정 작용 그리고 새로운 염(salts)의 침전작용을 반복하면서 석재 내부와 외부의 암석 및 결정에 균열과 미세열극 등이 생성되어 석재 자체의 구조적 안정성에 영향을 주고 있다. 따라서 감은사지 석탑은 지리적 환경 차이로 인해 일반적인 환경의 석조물들과는 다른 형태의 풍화양상을 보이고 있어서 풍화양상 및 풍화형태에 대한 정확한 연구와 이해를 바탕으로 보존대책이 마련되어야 한다.