Metallogenic chronology and ore-controlling factors of the Xialonggang Pb-Zn-Sb polymetallic deposit in the Himalayan belt: Implications for post-collision extension mineralization

The Xialonggang Pb-Zn-Sb polymetallic deposit is located in the Zhaxikang ore concentration area on the eastern margin of the Himalayan metallogenic belt, which has recently achieved a major breakthrough in prospecting. However, the metallogenic chronology and key ore-controlling factors of the deposit remain unclear, restricting prospecting and exploration. In this paper, the sericite Ar-Ar dating method is used to determine the metallogenic age of the deposit. The results show that the sericite plateau age is (14.91±0.21) Ma and the corresponding isochron age is (14.66±0.47) Ma in the temperature range of 800–900℃. This age can represent the hydrothermal mineralization age of the Xialonggang Pb-Zn-Sb polymetallic deposit, indicating that the Xialonggang Pb-Zn-Sb polymetallic deposit formed in the Miocene. Based on systematic sorting of prospecting information, we suggest that the NE-SW-trending extensional fault structures, high-intensity Pb-Zn-Sb-Ag combined geochemical anomalies, medium-to-low resistance and medium-to-high polarizability geophysical anomalies are the key prospecting indicators. Comprehensive studies show that the Xialonggang Pb-Zn-Sb polymetallic deposit is similar to other Pb-Zn-Sb polymetallic deposits in the Zhaxikang ore concentration area, all of which are the products of remote mid-to-low temperature mineralization related to the Miocene leucogranite magmatism in Cuonadong. It is a typical representative of the mineralization during the post-collision extension stage in the Himalayan metallogenic belt. In addition, the key ore-controlling factors summarized in this paper will provide a demonstration case for the exploration of Pb-Zn-Sb polymetallic mineralization in the post-collision stage of the Himalayan belt.