Origin of Cenozoic 'reverse faults' in northeastern China-an example from the Rongxintun fault in the Liaohe basin, China

In northeastern China, Cenozoic 'reverse faults' can be found in most basins. It was proposed that these faults were the products of inversion tectonics during a Cenozoic regional compressional event. This explanation is inconsistent with regional structures that are dominated by normal faults on seismic profile. As a typical example, the Rongxintun fault in northeastern Liaohe basin is systemically analyzed on the basis of deformation style, sedimentary character, and systemic mapping using seismic data. We conclude that the Rongxintun fault was related to right-lateral strike slipping of the Yannan main fault during the late Paleogene when the Dongying deposition occurred, and it was a secondary right-lateral/reverse fault (P Plane Fault) of the Yannan strike-slip fault system. The fold was a fault related fold formed as a result of movement along the Rongxintun fault. According to this analysis of the Rongxintun fault, we conclude that the Cenozoic 'reverse fault' in northeastern China was a secondary right-lateral/reverse fault of a strike-slip fault system and did not represent a compressional event. This kind of mechanism of 'reverse faulting' is consistent with the fact that there was large-scale strike-slip faulting in northeastern China during the Cenozoic.