The Tarim basin experienced a complex tectonic evolutionary history from Sinian to Ceno zoic. Eight largescale and more than 20 subordinate unconformities defining tectonosequences of dif ferent 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 Sys tem, which formed in a rift or aulacogen setting and can been subdivided into two subordinate strati graphic units （supersequences）. Unconformity （Tgg） between Sinian and Cambrian with surface karsti fication is regarded as a postrift 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 car bonate continental margin or cratonic depression and the Late Ordovician submarine to neritic ret roarc foreland and cratonic depressions. The tectonic uplift related to the formation of the unconformity Tg5-2 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 Tg5 formed by a relatively strong compressive deformation, which caused an abrupt tec tonogeographic change of the basin from abyssal to a neritic setting in response to the collision andassociated tectonic deformation of the North Kunlun （昆仑） orogenesis during the Late Ordovician to the Early Silurian. Tectono stratigraphic unit III is composed of the Silurian and the Lower to Middle Devonian and character ized by the development of fluvial or deltaic and clastic littoral and neritic deposits.
