Altered dolomite features and petro-geochemical prospecting indicators in the Huize lead-zinc deposit

Dolomite is a host rock in the Huize superlarge lead-zinc deposit. The near-ore dolomite shows zonation in space and can be divided into three types, namely grayish white-white coarse-grained (pinhole) dolomite, beige (local miarolitic cavitiy) coarsegrained dolomite and pale red-red coarse grained crystalline dolomite. The authors analyzed the mineral assemblage zonation and fabric characteristics, and reached the conclusion that there exist significant differences between these types of dolomite in such aspects as the degree of recrystallization in dolomite, microstructure of dolomite, crystalline form of pyrite, vuggy fillings and fissures, and these differences can serve as important indicators for identifying ore- bearing dolomite. The authors also studied element geochemistry of near-ore dolomite and other three types of dolomites in Baizuo Formation (mineralized dolomite, coarsegrained dolomite, and dolomitic limestone). According to the relationships between major element content of dolomites and the distance from the ore body and between major element content of dolomites and CaO content, the authors investigated the alteration of rocks and determined the hydrothermal alteration parameters of the coarse-grained dolomites, which are SiO2, MgO /CaO, K2O / CaO and Al2O3/TFe2O3.