The Yinshan poly metallic deposit is a hydrothermal deposit which closely related to the acidic intermediate volcanic subvolcanic rocks in age of Late Jurassic. The clay minerals formed in the hydrothernal alteration mainly consist of illite, which was a result of illitiztion of feldspar during the fluid rock interaction. The crystallinity of illite was closely associated with ore-forming fluid flow action. The nature, composition, fluid/rock ratios and fluid flow of ore-forming fluid restrict the forming of illite. In first episode of Pb-Zn-Ag mineralization, the fluid/rock ratios was relatively lower, fluid flow was mainly by pore osmosis, and the solute transported slowly, the illite presenting a little swelling layers. In the second episode of Cu-Au mineralization fluid/rock ratio was relatively higher, and fluid flow was mainly through fractures or channel. The solute transported quickly, the illite presenting no swelling layers. The paper suggested that illitization was closely related to Pb, Zn and Ag mineralization, whereas chloritization related to Cu and Au mineralization. The assemblages of clay minerals, the distribution and structural features of illite are indicators of temperature variation, and the type and intensity of hydrothermal alteration are clues to explore Cu, Au or Pb, Zn, Ag mineralizations in the district.
Li Xiaofeng,Hua Renmin,Ji Junfeng et al. ORIGIN OF ILLITE AND ITS RELATION WITH ORE-FORMING FLUIDS IN YINSHAN POLYMETALLIC DEPOSIT, DEXING,JIANGXI PROVINCE[J]. Chinese Journal of Geology, 2002, (1): 86-95.