Geochemistry and U-Pb geochronology of apatite from the Jiadi carlin-type gold deposit in the southwestern Guizhou, China

<p indent="0mm">The Jiadi gold deposit is a typical representative of Carlin-type Au deposits with its ores hosted in basaltic rocks. However, the geochronological study of the basalt-hosted Carlin-type gold deposit which are different to the sedimentary rocks-hosted deposits in the Southwestern Guizhou has not been addressed. In this paper, based on the comparative study of mineralized basalt samples in the Jiadi deposit and unaltered basalt samples outside of the deposit by employing the TIMA Integrated Mineral Analyzer, we have carried out the EPMA analysis, in-situ LA-ICP-MS trace element analysis and U-Pb dating of hydrothermal apatites associated with the gold mineralization in the Jiadi deposit. The results indicate that the hydrothermal apatite in the deposit is characterized with the enrichment of middle rare earth elements (MREE), and its U-Pb age is <sc>155.2±9.4 Ma,</sc> which are respectively consistent with geochemical characteristics and metallogenic ages of hydrothermal apatite, hydrothermal calcite, fluorite, and dolomite in the sedimentary rocks-hosted Carlin-type gold deposits in the southwestern Guizhou. These characteristics suggest that both the basalt-hosted and sedimentary rocks-hosted Carlin-type gold deposits in the southwestern Guizhou were formed in the regional metallogenic dynamic background of the southwestern Guizhou which resulted from extensive magmatisms and mineralizations in South China which were led by the lithospheric stretching and thinning and the upwelling of asthenospheric materials due to the subduction of the Pacific plate toward the Eurasia plate during the Yanshanian period.