CHARACTERISTICS AND PALEO-FLUID ACTIVITY IMPLICATIONS OF FLUID INCLUSION AND ISOTOPE OF CALCITE VEINS IN SHIZHU SYNCLINORIUM, MID-YANGTZE, CHINA

摘要

Fluid inclusion and isotope analysis were carried out to investigate the paleo-fluid activity of upper assemblage of Shizhu synclinorium. Microthermometric results combined with crystal morphologies and microscopic interpenetration indicate there had been multiphase release and injection of fluids in formational fracture. Two-phase aqueous inclusions in calcite indicate precipitation at 78- 215°C and salinity of 11.81-20.82%. C, O and Sr isotopes of calcite veins suggest diagenetic fluids originated from the dissolved of the host marine carbonates and, less commonly, affected by the degradation of organic matter in the Permian. Integrating Th with burial and thermal history modeling show large scale fluid flow in formational fracture and calcite vines filling mainly occurred at 145~60Ma, which initiated by Yanshanian tectonic compression and uplift.