The Xiaojiashan Tungsten deposit in the Barkol district, Xinjiang, China: geological features and ore-forming fluid composition

Abstract

The Xiaojiashan Tungsten deposit is located in Barkol district, Xinjiang. The ore bodies occur in the Hercynian granite intrusions and contact between the intrusion and wallrock which consists of the second lithologic section of the first Sub-Formation in Middle Devonian Dananhu Formation (D2d1 2 ). Quadrupole mass spectrometry reveals that fluid inclusions contain major vapor phase contents of CO2, H2O. Meanwhile, fluid inclusions contain major liquid phase contents of Cl -, Na + . It can be speculated that ore-forming fluid of the Xiaojiashan wolframite deposit is characterized by a CO2-rich, low salinity, and H2O-CO2-NaCl system. During ore-forming process, the magmatic water had separated from magmatic intrusions and ore-bearing complex was taken to a portion where tungsten-bearing ores could be mineralized.