Abstract:

Abstract:  Fluid veins widely developed in the Daqingshan thrustnappe, and can be divided into filled veins and edged veins according to their occurrences. According to their age,the formation of the fluid veins can be classified into three phases: the first phase quartz veins, the second phase quartz veins and the late phase calcite veins. The types of fluid inclusions in the first phase quartz veins is relatively complex, which contain twophase aqueous, threephase CO2bearing, pure CO2 and single phase aqueous fluid inclusions, respectively; analytical data revealed that their forming solutions came from lower crust or upper mantle. The second phase quartz veins contain only twophase aqueous and single phase aqueous fluid inclusions; fluids came from meteoric water which interfused with magmatic water. The late calcite veins contain twophase aqueous and a few single phase aqueous fluid inclusions; fluids came from interlayer solutions. The evolution history of Daqingshan thrustnappe system is determined according to the deformation phases, time and the depth data of those different kinds of veins. The thrusting of IndoChinese occurred at 78 km in the crust, the  thrusting of middle Yanshanian occurred at 36 km in the crust and the  thrusting of late Yanshanian within 2 km in the crust.

Key words:

Key words: Daqingshan; thrust; fluid inclusion; hydrothermal veins