The northwest margin of the Sichuan Basin is extensively developed with Neoproterozoic (700-1000 Ma) igneous rock
[37⇓-39]. The South China block may be involved in the assembly and breakup of the Rodinia supercontinent. Recent studies believe that the South China block belongs to the active continental margin
[40⇓⇓⇓-44], which is consistent with the existence of the 730-850 Ma circumferential Rodinia subduction system
[45⇓⇓-48]. According to the NE-striking Nanhua magmatic belt
[37⇓-39] developed in the northwest margin of the Sichuan Basin and the NE-striking high magnetic anomaly zone
[32], it is believed that the northwest margin of the Sichuan Basin underwent NW-SE forward to retreat of subduction from the Proto-Tethys Ocean in the Neoproterozoic period, and the subduction direction was perpendicular to the magmatic belt. The subduction force from the plate margin was transmitted to the plate interior, and the differential contraction deformation may directly induce the formation of NW-striking intraplate strike-slip faults (
Fig. 10a). Subsequently, the plate subduction retreated to form an extensional background in the plate, and the plate began to breakup along the early magma zone, forming a Nanhuanian rift system dominated by NE-striking, NEE-striking and nearly WE-striking faults, or a rift system controlled by normal faults in the NW direction
[37,47 -48]. The normal boundary faults of the rift basin were linked together by perpendicular transfer faults (
Fig. 10b), which may be the original pre-existing structures activated by late strike-slip faults. But the nature and activity of faults in this period are difficult to confirm by data. Deep geophysical data such as gravity anomalies and aeromagnetic anomalies
[46] revealed that more than 10 deep NW-striking and NE-striking deep basement faults developed in the basin
[32], and there were obvious NE-striking magnetic anomaly zones separated by the NW-striking tectonic structures in the central Sichuan Basin
[49]. These deep NE-striking, NEE-striking and NW-striking faults are consistent with the strike-slip fault framework in the Sinian and above strata, which are the basis for the formation and development of late strike-slip faults.