四川盆地德阳—安岳槽盆东侧台缘断裂特征及其形成演化OA

A large N-S trending Deyang-Anyue Trough Basin developed in the Sinian to Lower Cambrian strata of the Sichuan Basin.Its basin attributes and formation mechanisms remain debated,constraining hydrocarbon exploration.Using 3D seismic data,this study examines faults along the eastern platform margin(Gaomo sec-tion)of the Anyue Trough.By interpreting fault development and structural features,we analyze their nature,evolution,and relationship with trough formation.Results show:(1)Various fault types developed on platform margins of different orientations(N-S,E-W,NW-SE),including minor normal faults,steep through-going double faults with strike-slip features,and flower-structure strike-slip faults,with properties changing over time.(2)Fault activity from Late Sinian to Permian followed a weak-strong-weak pattern,intensifying from Dengying Formation to Early Cambrian Qiongzhusi Formation deposition,evolving from isolated segments to linked systems.During the Permian,faults showed inherited activity with spatial migration.Spatially,activity varied segmentally,weaker in N-S segments and stronger in transitional zones.(3)Platform margin faults evolved through stages:pre-Sinian inherited basement fault formation,isolated fault development during Late Sinian Dengying deposition,growth and maturation in Early Cambrian Qiongzhusi deposition,and multiple weak reactivations from Early Cambrian to Permian.(4)The fault framework was initially controlled by pre-existing basement heterogeneity.Subsequent shifts in regional stress drove multiple episodes of differential reac-tivation,influencing platform margin morphology and fault activity migration.