Ore-forming time of the Erlihe Pb-Zn deposit in the Fengxian-Taibai ore concentration area, Shaanxi Province: Evidence from the Rb-Sr isotopic dating of sphalerites
陕西省凤太矿集区二里河铅锌矿床的成矿时代: 来自闪锌矿Rb-Sr同位素年龄的证据

The Bafangshan-Erlihe Pb-Zn deposit is located on the northwest of the Fengxian-Taibai (abbreviated Fengtai) ore concentration area, and the orebodies mainly occur at the contact zone between the Gudaoling Formation of Middle Devonian and the Xinghongpu Formation of Upper Devonian, controlled by NWW-trending Bafangshan-Erlihe anticline. In this paper, the Rb-Sr isotopic dating is carried out on the sphalerite from the main mineralization stage of the Erlihe Pb-Zn deposit, yielding an isochron age of 220.7±7.3Ma, showing that the deposit formed in Late Triassic, and the age data is also a constraint on the Pb-Zn ore-forming time of the whole Fengtai ore concentration area. The 87Sr/86Sri value of the sphalerite is 0.714145±0.000031, indicating that the ore-forming materials are mainly derived from the continental crust. In the context of regional geology, we suggest that the Erlihe Pb-Zn deposit is the product of the regional intensive tectono-magmatic-mineralization processes developed in the Fengxian-Taibai ore concentration area in Triassic .