鄂尔多斯超级盆地形成演化OA

As a super basin,the Ordos Basin currently lacks a unified understanding of its Paleozoic-early Mesozoic tectono-sedimentary evolutionary stages and key basin prototypes.This study systematically examines the tectono-sedimentary evolution of the Hinggan-Mongolian and Qin-Qi orogenic belts,regional unconformities and distribution of Paleozoic formations within the basin,stratigraphic genesis and distribution of volcanic tuff events,and sedimentary filling characteristics from the Paleozoic to Middle Triassic.The tectono-sedimentary evolution of the Ordos Basin is divided into eight stages in this periods.During the Cambrian and Early-Middle Ordovician periods,three types of basin prototypes coexisted:passive continental margin subsidence along the southwestern margin,northwest margin graben,and intra-cratonic subsidence in the central-eastern region.The Late Ordovician had coexistence of two basin prototypes:post-arc rift along the southwestern margin and northwest margin graben.The Late Carboniferous-Early Permian witnessed coexistence of two basin prototypes:intra-cratonic subsidence and post-arc rift along the northwest margin.Following mid-Permian land-building movements,intra-cratonic subsidence and Baotou foreland basin developed during the Late Permian-Middle Triassic.Based on the development and distribution of basin prototypes from the Cambrian to Middle Triassic,their superimposed relationships,and the oil and gas geological conditions they control,combined with recent exploration progress,this study proposes that the Lower Paleozoic formations along the southern margin,sub-salt formations in the central-eastern region,Upper Ordovician shale oil and gas along the western margin,and multi-type natural gas in the Upper Paleozoic constitute the oil and gas succession zones of the Ordos super basin.