Abstract:

 The activity of previous basement fault has great impact on the deformation of the cover, especially when the stress immediately acts on the basement. The sandbox experiments were employed to simulate the passive deformation of cover fault block in case the deep basement was deformed through strikeslip fault in a uniform stress field. The experiments indicated that a nearly symmetrical strikeslip extension rift formed when extension component exists, whereas a symmetrical bending fold, which is bounded by strikeslip thrusts, was formed when compression component exists. The deformation is characterized by a typical strikeslip structure on the section, and the dimension of deformation region was related to the intensity of extension or compression component. When the stress from basement imposed on cover block, there would be rotation and internal deformation in the previous cover consisting of fault blocks, forming alternative extension and compression. When the basement faults show multiple activations or even reverse movement, some complex structures could be formed on the surface. The ChengdaoKendong buriedhill belt in the middle section of the TanchengLujiang Fault is a typical example of the structure controlled by strikesliding basement. The experiments proved that the reversal and strike sliding of the basement resulted in the rotation and torsion of the fault block, and the incomplete reversal of the cover blocks formed composite flower structure.

Key words:

Key words: basement fault; strikeslip fault; mechanical simulation; sandbox experiment; passive deformation; TanchengLujiang Fault