Genetic linkage between coeval high-temperature W and low-temperature Sb-Au-W mineralization in Xiangzhong metallogenic province, South China: Constraints from U-Pb ages and scheelite trace elements

The Xiangzhong metallogenic province in South China comprises both granite-related relatively high-temperature (T) W deposits and sedimentary rocks hosting relatively low-T Sb-Au-W deposits. To address the genetic relationship between these two different types of deposits, in situ U-Pb age and scheelite trace element analyses were conducted for six deposits within this province. Our new age data of the high-T W deposits and low-T Sb-Au-W deposits range from 214.9 ± 4.0 Ma to 207.6 ± 2.7 Ma and from 140.0 ± 8.6 Ma to 133.7 ± 3.6 Ma, respectively. Accordingly, two episodes of mineralization are identified in this province, i.e., 225−200 Ma and 160−120 Ma. The older episode produced both types of deposits, whereas the younger episode produced only the low-T Sb-Au-W deposits. Our new scheelite chemical data show systematic changes from coeval high-T W deposits to low-T Sb-Au-W deposits, that are decreasing rare earth element, Mo, Nb, Mn, and Na contents coupled by increasing Eu anomaly, Sr content, and Sr/Mo ratios. Such variations are consistent with mixing between high-T magmatic-hydrothermal fluids and low-T fluids of circulating meteoric water after interaction with metasedimentary rocks. The comparable scheelite trace element compositions between the two periods of low-T Sb-Au-W deposits imply that this type of deposits may share a similar ore-forming fluid. This implies that there could be hidden high-T W deposits formed during the younger episode in this province. Therefore, we have constructed a genetic model linking the two types of deposits, which can serve as a valuable tool for regional mineral exploration.