Abstract:There are many high-steep anticlines with Northeast-striking to East-northeast-striking in the Eastern Sichuan Basin.There is uncertainty in the interpretation of the structural styles owing to most of the wells drilled in the area with the hydrocarbon accumulation of Carboniferous layers located in the high structural position,in which are relatively shallower and unrevealed deeper strata,and the quality of 2D seismic data is poor in the core and steep limb in the high-steep anticlines.Many researchers conclude that the high-steep anticlines are interpreted as the typical Jura-type folds,i.e,detachment folds.This paper has given a different idea in the Mingyuexia high-steep anticline Methods: In this study,we reanalyze the geometry of the Mingyuexia anticline based on the seismic data with the new wide-line two-dimensional seismic-reflection data.The horizons are calibrated by wells data and a 1: 20000 regional geological map,and our geometric models are built under fault-related fold theories and conservation of layer thickness.The deformation times are determined by previous apatite fission-track (AFT) and (U-Th)/He thermochronology studies.Results: Three major detachments are recognized regionally within the anticline: ① a lower gypsum-bearing detachment mainly developed in the lower to middle Cambrian Longwangmiao Formation,the Gaotai Formation,and the Qiongzhusi Formation and ② a dark-gray shale and mudstone layers of the middle detachment in the lower Silurian Longmaxi Formation,③ an upper gypsum-bearing detachment mainly developed in the Lower Triassic Jialingjiang Formation and the Middle Triassic Leikoupou Formation.The a deep westward-thrusting lower wedged-shaped structure and a shallower westward- thrusting upper wedge structures have been identified based on the level of the wedge points with respect to layered Paleozoic-Mesozoic sedimentary rocks.The high-steep Mingyuexia anticline is interpreted to be the lower wedged-shaped structure superimposed with upper wedged-shaped structure.The upper wedge structure, which is commonly observed where thrust developed from the middle detachment of the Sinian mudstones and shale into an upper gypsum-bearing detachment of Lower Triassic Jialingjiang Formation.The lower wedge structure is commonly interpreted as thrusts developed from the gypsum-bearing detachment of Lower to middle Cambrian Longwangmiao and Gaotai Formations into the middle detachment of the Sinian mudstones and shale.We have proposed geometrical models for the development of two-stage vertical superimposed double wedging with multiple detachments.Previous apatite fission-track (AFT) and (U-Th)/He thermochronology studies by many researchers in the eastern Sichuan Basin areas have provided that the tectonic rapid uplift and denudation of the eastern Sichuan high-steep anticline’s belt suggest two age ranges: the Early Cretaceous and Neogene.Conclusions: We speculate that the upper wedged-shaped structure in the Silurian mudstone and shale developed in the early time,i.e,the Early Cretaceous and the lower wedge-shaped structure in the Sinian mudstones and shale, or Cambrian salt developed in the late time,i.e,the Neogene.The Mingyuexia anticline provides an excellent example of the lower wedge structure superposed vertically with the upper wedge structure in the Eastern Sichuan high-steep anticline’s belt.