The Tarim basin experienced a complex tectonic evolutionary history from Sinian to Cenozoic.Eight large-scale and more than 20 subordinate unconformities defining tectonosequences of different protobasins formed in various tectonic settings have been identified within the Phanerozoic in the Tarim basin,their distribution determining the general characteristics of sequence stratigraphic framework of the basin.Tectonostratigraphic unit I(magasequence) consists mainly of the Sinian System,which formed in a rift or aulacogen setting and can been subdivided into two subordinate stratigraphic units(supersequences).Unconformity(T g9) between Sinian and Cambrian with surface karstification is regarded as a post-rift unconformity.Tectonostratigraphic unit II comprises the Cambrian and the Ordovician and can be divided into six subordinate tectonostratigraphic units,recording the tectonogeographic evolution of the prototype basins from Cambrian to Early Ordovician passive carbonate continental margin or cratonic depression and the Late Ordovician submarine to neritic retroarc foreland and cratonic depressions.The tectonic uplift related to the formation of the unconformity T g5-2 resulted in the remarkable change in basin tectonic setting from a passive divergent to an active convergent,with the development of the Tazhong(塔中) uplift,the Tangguzibasi(塘古孜巴斯),and the northern depression at the end of the Middle to the early Late Ordovician.The widespread angular unconformity T g5 formed by a relatively strong compressive deformation,which caused an abrupt tectonogeographic change of the basin from abyssal to a neritic setting in response to the collision and associated tectonic deformation of the North Kunlun(昆仑) orogenesis during the Late Ordovician to the Early Silurian.Tectonostratigraphic unit III is composed of the Silurian and the Lower to Middle Devonian and characterized by the development of fluvial or deltaic and clastic littoral and neritic deposits.Large-scale terrigenous clastic depositional wed
