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Two ductile shear zones trending EW and NNE respectively not only controlled the tectonic framework of the northern North China, but also constrained the geody-namic background for gold mineralization in this region. Field observations and microstructural analyses reveal that the EW trending ductile shear zones are mainly contributed to dextral compressional deformation resulting from top-to-the-southeast oblique thrust shearing, whereas the NNE trending ones are genetically related to sinistral strike-slip and extensional faulting. One sample from the former yielded an 40Ar-39Ar plateau age of (219±4) Ma (Bi) and two samples from the latter gave 40Ar-39Ar plateau ages of (116± 2) Ma (Bi) and (127±3) Ma (Bi). These ages provide constraints on the top-to-the-southeast oblique thrusting event occurring in Late Triassic and the sinistral extensional and strike-slip faulting event which occurred in Early Cretaceous.
Two ductile shear zones trending EW and NNE respectively not only controlled the tectonic framework of the northern North China, but also constrained the geody-namic background for gold mineralization in this region. Field observations and microstructural analyzes reveal that the EW trending ductile shear zones are mainly contributed to dextral compressional deformation caused from top-to-the-southeast oblique thrust shearing, while the NNE trending ones are genetically related to sinistral strike-slip and extensional faulting. One sample from the former 219 ± 4) Ma (Bi) and two samples from the latter gave 40Ar-39Ar plateau ages (116 ± 2) Ma (Bi) and (127 ± 3) Ma -the-southeast oblique thrusting event occurring in Late Triassic and the sinistral extensional and strike-slip faulting event occurred in Early Cretaceous.