Journal of the Mineralogical Society of Korea (한국광물학회지)

The Mineralogical Society of Korea (한국광물학회)
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Mineralogical Change of Acid Sulfate Weathering of Hydrothermally Altered Pyritic Andesite

열수변질 안산암 기원의 함황광물과 특이산성토적 풍화에 따른 광물학적 변화

  • Kim, Jae-Gon (Department of Earth System Science, Yonsei University) ;
  • Jung, Pil-Kyun (National Institute of Agricultural Science and Technology, RDA) ;
  • Yun, Eul-Soo (NationalYongnam Agri.Expt. Stn., Plant Envron., Division) ;
  • Jung, Yeun-Tae (National Institute of Agricultural Science and Technology, RDA) ;
  • Hyon, Geun-Soo (National Institute of Agricultural Science and Technology, RDA) ;
  • Zhang, Yongsun (National Institute of Agricultural Science and Technology, RDA)
  • Published : 2000.09.01
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Abstract

Oxidation of pyrite has caused a serious environmental problem such as the acidification of soil and surface water. The mineralogical change of acid sulfate weathering of hydrothermally altered andesite which contained 11.8% of pyrite and was exposed in atmosphere by lay out works for a residential area and a golf course was studied using X-ray diffraction (XRD) and electronmicroscopes. Ferrihydrite, jarosite, and an unidentified water soluble phase were observed as weathering products of the andesite. Under electronmicroscopes, showed aggregate of platy microcrystals; jarosite was platy morphology: water soluble Phase was columnar. Morphology of fresh Pyrite in the andesite changed from pyritrohedron to cubic in its frequency with increasing its particle size. The drainage water was acidic (pH 3.5) and in an equilibrium state with both ferrihydrite and jarosite.

황철석의 산화에 의한 토양 및 지표수의 산성화는 심각한 환경문제를 야기하여 왔다. 특이산 성토의 이차광물과 화학적 특징은 풍화과정을 반영하고 있다. 택지 및 골프장 조성과정에서 지표에 노출된 11.8% 황철석을 함유한 열수변질 안산암의 풍화에 따른 광물학적 변화를 X-선 회절, 전자현미경 (SEM, TEM), 배수의 화학분석을 통하여 연구하였다 수용성 염, ferrihydrite, jarosite가 풍화과정의 이차 광물로서 관찰되었다. 전자현미경하에서, ferrihydrite는 미세입자들의 입단, jarosite는 판상, 수용성 염은 기둥모양을 나타내었다. 안산암 내에 존재하는 황철석은 입자의 크기가 증가할수록 정육면체 형태/육각기둥 형태의 비가 증가하였다. 배수는 강산성 (pH 3.5) 이었으며 ferrihydrite, jarosite와 화학적 평형을 이루고 있었다.

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