The Primary Structure Controlled Mineralization in Weolseong Diatreme, Southern Korea

월성(月城) 다이아튜림의 층준(層準)에 따른 광화(鑛化) 현상(現狀)

  • Park, Ki-Hwa (Metallic Minerals Division, Korea Institute of Energy and Resources) ;
  • Oh, Mihn-Soo (Metallic Minerals Division, Korea Institute of Energy and Resources)
  • Published : 1987.02.28

Abstract

The Nokdong As-Zn deposit, located 28 km south of Kyeongju City, Southern Korea, has been investigated by a deep drilling programme. The mineralized zone is roughly 290m long and 180m wide at surface and is hosted in a pipe diatreme infilled with poor to well bedded felsic volcaniclastics. The diatreme was formed by explosive volcanic activity, of probably early Tertiary age, subsequent hydrothermal alteration and mineralization took place concurrently within stratigraphic layers in diatreme. Coarse volcaniclastics in the center part of the diatreme, together with complex systems of fracturing, acted as pathways for late hydrothermal fluids which caused alteration of volcanic material to sericite, chlorite and carbonate and precipitated ore minerals, quartz and calcite in the voids. Porosity and permeability were key factors in determining which portions of the layered diatreme were mineralized. The lower part of certain layers retained a relatively high porosity and were extensively mineralized. Metallic mineralization, consisting mostly of pyirte, sphalerite and arsenopyrite, is found as disseminations, tuff-breccia filling and veins.

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