Abstract:Objectives: The southern margin of the North China Block underwent complex intracontinental deformation during the Paleozoic. A- type folds parallel to the fault and near- horizontal mineral growth lineation developed in large numbers in the boundary faults of the Shirenshan block, which indicates that this block had undergone a tectonic stage dominated by strike- slip shear deformation. Methods: In this study, four cross sections were observed. We used geological mapping, key sections of the profile drawing, structural analysis and other conventional construction methods. We present new geochronological results, and document the emplacement Zircon U- Pb age of the sample. Results: Dynamics study shows that the Luoluan fault is characterized by NE subduction and left- lateral shear deformation, while the Lushan fault is characterized by NW thrust and right- lateral shear deformation, and that the Shirenshan block sandwiched therein displays features of being westward and upward extruding. Using typical rock samples for isotope dating to define the age of the fault activity, zircon U- Pb dating results of the syntectonic granite veins in the Luoluan fault are (413.6±7.4) Ma; and in the Lushan fault, inside the structural lentils with obvious strike- slip shear characteristics, zircon dating results of the veins are (419.3±11.2) Ma. Conclusions: Given that the movement directions of the Luoluan and Lushan faults are different, and that the isotope chronology study has pinpointed the time of the strike- slip deformation of the two faults to the end of the Late Paleozoic Devonian, the structural characteristics of the Shirenshan block being westward extruding is jointly constituted. This finding also suggests that continents after collision soon enter the evolution stage of intracontinental deformation which consists mainly of lateral extrusion and strike- slip displacement of orogenic belts.