摘要
Shuicheng-Ziyun-Nandan deep fault is a well-known belt expanding across two provinces(Guizhou and Guangxi),along both sides distributing a series of diverse deposit types,and the large Devonian barite deposit is an important ore deposit in Zhenning County,Guizhou.The large barite deposit,located in the northwest margin of Shuicheng-Ziyun-Nandan deep fault was studied on the basis of the sedimentation characteristics,geochemistry and metallogenic background.The results revealed coexistence of a variety of hydrothermal water sedimentary structures characteristics such as laminar structures,barite-banded structure,brecciated structure,barite-fragmental structure,massive structure,and so on.Macroelement study indicated that the deposit was formed probably by synsedimentation of SiO2 and ore-bearing sulfate fluid.Besides,geochemistry of the large barite deposits of the Devonian shows the enrichment of Sr,Zn and W,strongly suggesting that the barite depo-sits is hydrothermal sedimentation in origin.The diagrams of lgU-lgTh and Cr-Zr in the barite deposit also present the features of hydrothermal sedimentation.According to the REE distribution pattern,LREE were enriched and Eu was positive while Ce was negative,which also shows a hydrothermal feature.As a result,we believed that the large barite deposits located in Zhenning formed by hydrothermal exhalative mineralization.