Diverse and multistage Mo, Au, Ag–Pb–Zn and Cu deposits in the Xiong'er Terrane, East Qinling: From Triassic Cu mineralization

The Xiong'er Terrane is one of the representative regions in East Qinling Orogenic Belt. Various polymetallic deposits have been discovered in the Xiong'er Terrane, such as porphyry Mo, carbonatite-hosted type Mo, quartz-vein type Mo, breccia-pipes type Au and orogenic-type Au, Ag–Pb–Zn deposits, indicating that diverse significant mineralization occurred in the Xiong'er Terrane. Recently, numerous Cu deposits have been observed in the Xiong'er Terrane. Xianglugou is a quartz vein-type copper mineralization which was discovered in Xiayu district, southern of the Xiong'er Terrane. Four chalcopyrite samples from Xianglugou yield Re–Os isochron age of 230 ± 31 Ma (2σ, MSWD = 0.8). This is the first evidence for Triassic Cu mineralization in the Xiong'er Terrane. This not only shows the Xiong'er Terrane contains considerable Mo, Au and Ag–Pb–Zn reserve, but also indicates that there is a great potential of Cu mineralization. The discoverable Cu mineralization can further emphasize the significance of the widespread Triassic mineralization and widened exploration ideas and goals in the future in the Xiong'er Terrane. The Xiong'er Terrane experienced three polymetallic mineralization events including Paleoproterozoic, Triassic and Late Jurassic to Early Cretaceous deposits during the Qinling Orogen evolution. These metallogenic events may be related to multiple tectonic events. The Paleoproterozoic mineralization was associated with the continental outgrowth occurred along the southern margin of the North China Craton before 1760 Ma. The Triassic Cu mineralization may be associated with the northward subduction of the North Qinling Orogen beneath the Huaxiong Block during the collision between North China Craton and Yangtze Craton. Late Jurassic to Early Cretaceous mineralization perhaps caused by decompressional extension of the Qinling Orogenic belts and the North China Craton intense destruction and lithospheric thinning, which is now generally related to the westward subduction of paleo-Pacific plate.