And Sichuan Ganluo, Board Ditch Causes Of Pb-zn Deposits And Prospecting Direction

The Zebangou Lead-Zinc deposit is situated in the north sect of Ganluo ore-forming subzone, Ganluo-Xiaojiang fracture zone in the western margin of the Yangtze platform.The deposit is hosted in ashen-atrament dolomitic powdery siltstone and sandy dolostone of Dengying Formation of Upper Sinian, the interbedded fracture zone is the structure of the deposit, Malaha large faultage pass by field east. Emeishan Basalt emerge in southwest and southeast of the ore-forming subzone.There are high content of Pb, Zn and organic matter in the wall rack of the deposit and the upper Paleozic stratum, which would provide substance for ore-forming by the movement of later rainwater and mixed themic water.Through the study on the race earth and trace elements, the isotopes of sulfur, lead, hydrogen, oxygen and carbon, and fluid inclusions, the author concludes that the metallogenic material drived from the Dengying Formation and Palaeozoic Erathem; the main metallogenic fluid came from the meteoric water. The most ore-forming thermal solution is characterized by the middle salinity:9.9¹5.6wt.NaCl%,T=84 253°C, P=10⁶5.5MPa; Lead and Zinc were migrated in the form of PbCl₄^2- ZnCl₄^2- or organic-complex in the solution. The change of temperature lead to the thermochemical sulphat reduction(TSR) and the decompounding of organic-complexs which offer added S^2- ,Pb²⁺ and Zn²⁺, and promoting the sedimentation of PbS, ZnS from the ore-forming thermal solution.By the cognition above, and combined with the deposits ' feature and their distribution on the ore-forming zone, a ore-forming for the deposit established and the ore-prospecting direction near by this area are suggested.