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Chang-Qing Zheng, Jilin University (China)
Wei Jin, Jilin University (China)
Xing-Zhou Zhang, Jilin University (China)
Zhi-Hong Ma, Jilin University (China)
Jian-Bo Zhou, Jilin University (China)
Hu Wang, Jilin University (China)
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The Songliao Basin, a famous Chinese Mesozoic-Cenozoic continental petroliferous Basins in the NE China, was multiple belt of the eastern segments of the Central Asian Orogenic Belt (CAOB) and west pacific tectonic belt. The Songliao Basin is in meddle of the NE China. The Jinxing ductile shear zone is a large-scale ductile shear zone along the western boundary of the Songliao Basin. Its kinematics and the ages of the movement have not been studied, which limits the study of the tectonic evolution of the Songliao Basin, especially the Oil and Gas exploration and development of the western Songliao Basin.
Jinxing area is a typical outcropped of the Jinxing ductile shear zone, and it consists of banded granitic mylonite, mega-augen granitic mylonite, and granitic-schist. There are two sets of mylonitic foliations and stretching lineations. The first foliation is ca. N60W; 50NW with a lineation of ca. S45W, 10SW, the others is S60W, 65SW with a lineation of N25E, 10NE. The motion indicators within the shear zone indicate that the Jinxing ductile shear zone is left-lateral strike-slip fault. In this study, we used the SHRIMP zircon U-Pb and biotite laser Ar-Ar dating method to get the ages of the tectonic events of the Jinxing ductile shear zone. The SHRIMP zircon U-Pb dating from a granitic mylonite gives a 295Ma age and biotite laser Ar-Ar dating of the same sample yields an age of 113Ma.
The ages indicate that the protolith of the granitic mylonite is Early Permian (295Ma) in age and deformation age for the same sample is Early Cretaceous (113Ma). These data also show that the Songliao Basin experienced transgression evolution stage, and western boundary was controlled by the Jinxing shear zone during Early Cretaceous. Consideration of the regional tectonic setting of NE China, we suggest that the formation of this large-scale ductile shear zone with NNE trending might be related to the subduction of the Pacific Plate under to the Eurasian Plate.
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