Analogue Modelling Of Fold-and-Thrust Belts Controlled By Multiple Detachment Layers: An Example From The Eastern Sichuan Basin

Sichuan basin is one of the major basins in China that has characterized with an old history of hydrocarbon exploration industry development,the fold and thrust belt in the study area is located in the middle part of the Yangtze plate,this study comprises and analyzes detailed structural characterization of fold-and-thrust belts,structural deformational and quantitative evolution,characterization of experimental models results,quantitative evolution of structural deformation,and the controlling key factors of the multiple detachment layers in the eastern Sichuan basin.This thesis,demonstrated the characteristics of fold-and-thrust belts in the study area through geologic map data,seismic data,and reconstruction balanced cross-sections compiled and applied into the Midland Valley Move? software suite,structural restoration is carried out through the analysis and reconstruct of two large regional seismic sections(A-A’),(B-B’),which crossed the fold-and-thrust belts in the study area along with the NW-SE directions,furthermore,balanced restoration shows that the shortening rate is about～26.13 km on cross-section(A-A’)while on the cross-section(B-B’)reached ～20.34%km.Comprehensive analyses of kinematics and balanced restoration reveals tectonic evolution of the detachment folds and faulted detachment folds.Five groups of experimental models carried out to investigate the development and kinematics of the fold and thrust belt,associated with different impact factors,which are layers’ thickness,detachment layers,and shortening amount,based on the experiments’ results the deformation evolution and kinematical analysis was identified,with the presence of three detachment layers which are the lower Cambrian salt layer as major and main impact detachment on the deformation evolution,the Silurian shale layer and the lower Triassic gypsum salt layer,respectively,both are representing as secondary impact detachments on the deformation evolution of the fold and thrust belt in the eastern Sichuan basin.