Structural characteristics and genetic analysis of Tongcheng fault in Jinhu sag

Key words:  Jinhu sag  Tongcheng fault  Cenozoic  strike-slip fault  fault genesis

Abstract:

Using the high-precision 3D seismic data, and based on the previous results of structural analysis of Jinhu sag and Subei Basin, this paper analyzed the structural features and discussed the genesis of the Tongcheng fault. The results show that the Tongcheng fault strikes SN, and its fault-plane has the feature of "Ribbon Effect ". The scale, activity and section structure pattern of the faults in the west side are different from the east side. The Tongcheng fault has no genetic relationship with the faults on its both sides, but it may have played a role in structural dividing. The regional stress and pre-structure has important influence on the fault 's evolution. During Paleocene to early Eocene, the Tongcheng fault formed and was controlled by NW-SE extension. The fault was a transfer fault which played a role in the structural accommodating, but wasn 't affected by the strike-slip Tan-lu fault in this stage. In Eocene the Tongcheng fault grew and owned property of active strike-slip, controlled by the near SN extension. During Oligocene to early Miocene, the south plane of the fault reversed and the fault became a reverse fault caused with near EW compression. The Tongcheng fault began to form in extensional environment, and experienced local modification in compressional environment. In summary the fault is featured as strike-slip, multi-periodic activities and varying fault nature at different structural stage.