Full understanding basin-range system is the inevitable research trend of palaeogeographic reconstruction,in which an analysis of characteristic source-sink systems, both in stable tectonic region and active one,is an key step. Some magmatic and metamorphic records related to the Pan-African orogeny occure in the actively northern Tarim Block,but the characteristic tectonic event is seldom discovered from detrital depositions. For the Devonian-Carboniferous sandstones in the northern Tarim Block,the authors present in situ analysis on geochronology of detrital zircons in the paper. Detrital zircon U-Pb dating of the Lower Carboniferous Yeyungou Formation sandstones dominantly show the middle-late Neoproterozoic ages,corresponding to the duration of the Pan-African orogeny. The depositional records with such zircon ages were firstly and remarkably discovered in the study area. The corresponding εHf(t) values of the detrital zircons are almost negative,reflecting melting origin of the ancient crust. However,there was no obvious information on the Pan-African orogeny revealed by detrital zircons of sandstones from the sedimentary strata underlying or overlying the Yeyungou Formation. In the Devonian,southward subduction of the South Tianshan Ocean led to island arc systems developed in the northern margin of Tarim Block. Up to the early Visean of early Carboniferous,the South Tianshan Ocean gradually closed,which evidently changed tectonic-palaeogeographic framework of the study area due to collage and collision between tectonic blocks. As a result,subsequently magmatic and metamorphic basements related to the Pan-African orogeny rapidly uplifted,which provided primary provenance for the Yeyungou Formation sedimentation. In the Late Carboniferous,the exhumation of the above crystalline basements ceased due to sea level rise and synchronous sedimentary overlap. Based on integrated regional correlation of detrital zircon U-Pb geochronological data,no detrital deposition recording the Pan-African event can be found from the Phanerozoic strata except the Lower Carboniferous mentioned above. In addition, few detrital deposition recording the Pan-African event was also reported from the Upper Ordovician Sangtamu Formation. These evidences probably demonstrate the northern Tarim Block finitely influenced by the Pan-African orogeny and,on the other hand,the associated basement rocks mainly exhumated during the Early Carboniferous and, shortly, the Late Ordovician. The above revealed informations are of important significances to realize the Paleozoic palaeogeomorphology,clastic source-sink system and tectonic paleogeography of the northern Tarim Block.
