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

Abstract 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.