Jurassic source-to-sink evolution in the South Tian Shan, NW China: Response to the Middle–Late Jurassic tectonic inversion

Jurassic strata along the South Tian Shan piedmont of the southwestern Tarim Basin record Mesozoic intracontinental deformation and its influence on basin evolution. Although Middle–Late Jurassic deformation is widely documented across the Tian Shan, its effects on provenance and source-to-sink systems along the southern piedmont remain poorly constrained. We integrate sedimentological observations, sandstone petrography, heavy-mineral assemblages, and detrital zircon U–Pb geochronology from the Kuzigongsu Basin to reconstruct Jurassic sediment routing and evaluate its tectonic response. Two principal provenance systems supplied the basin: Ordovician–Silurian arc volcanic rocks along the northern Tarim margin, with minor input from Permian granitoids and recycled South Tian Shan successions; and metasedimentary rocks of the Wulagen uplift to the south. During the Early–Middle Jurassic, rapid subsidence in a strike-slip-related transtensional basin accommodated alluvial-fan and fluvial deposits followed by lacustrine expansion. At the Middle–Late Jurassic transition, stratigraphic omission, local angular unconformities, and renewed coarse-grained alluvial-fan deposition record localized basin inversion. Petrographic, heavy-mineral, and detrital zircon data nevertheless indicate broadly persistent source regions. Deformation therefore modified basin architecture and accommodation without exposing a new first-order source terrane or fundamentally reorganizing drainage. We tentatively relate the Late Jurassic inversion to far-field intracontinental stresses associated with Karakoram–Lhasa convergence along the southern Eurasian margin, although the local record does not uniquely identify this driver. The Kuzigongsu record shows that inherited intracontinental basins may undergo marked structural reorganization while retaining long-lived source-to-sink systems.