Fault Characteristics And Formation And Evolution Of Amman Transitional Zone

The Amman transition zone lies in the north of the hinterland of the Tarim Basin,between the Awati Depression and the Mangar Depression,with the northern Tabei uplift and the southeastern Tazhong low uplift as the boundary.It is a special "saddle" structure,showing depression in the north-south and uplift in the East-West.Under the influence of active tectonics,the structural characteristics of this area are complex.In this paper,coherence cube were employed to interpret high-precision three-dimensional seismic data,combined with field exploration,the fault characteristics,fault system and formation and evolution of the Aman area are studied in depth from a new perspective.The Amman transitional zone has undergone multiple tectonic cycles such as Caledonian,Hercynian,Indosinian and Yanshan tectonic cycles with strike-slip faults developing in the deep part and normal faults in the shallow part.Among them,strike-slip faults are mainly network,parallel,echelon,oblique intersection and horsetail in plane,and the strike-slip section in Aman area has obvious sectional characteristics.Flower structure is the main structure in section,which can be divided into three categories: complex flower structure,simple flower structure and simple strike-slip fault.According to the fault scale,cut-through horizon and dynamic mechanism,strike-slip faults can be divided into four stages: Early Caledonian,Middle Caledonian Episode III,Late Caledonian and Late Hercynian.The strike-slip faults developed during in the Middle Caledonian Episode III to the Late Hercynian period are are extremely active and obvious strike-slip faults.The strike-slip faults in the Late Hercynian study area are basically stereotyped.Influenced by multi-stage differential stress in the basin,the formation and evolution of strike-slip faults in Aman area are synchronous with the evolution of the whole Tarim Basin,which can be divided into small-scale echelon fault development stage(Early Caledonian),torsional structure development stage(Middle and Late Caledonian),inherited torsional structure development stage(Late Hercynian),adjustment development stage(Indosinian-Yanshanian).Successive adjustment of development stages(Himalayan period),in which strike-slip faults began to develop in the Early Caledonian period,and basically finalized in the Late Hercynian period.