Late Tonian subduction to collisional tectonics in the southwestern Tarim Craton: Arc volcanism and sedimentary archives of terminal Rodinia amalgamation

The southwestern margin of the Tarim Craton preserves significant geological records related to the assembly and fragmentation of the Rodinia Supercontinent. However, its Neoproterozoic tectonic evolution remains debated, complicating the reconstruction of the Tarim Craton within the Rodinia framework. This study presents a multidisciplinary approach integrating stratigraphic, geochronological, geochemical, and provenance analyses of Tonian successions and tuffaceous interlayers to constrain the timing and mechanisms of contractional events in the southwestern Tarim Craton. The Tonian Silu Group shows a regressive succession from shallow marine to fluvial-deltaic environments, capped by a regional unconformity beneath Cryogenian-Ediacaran strata. Tuffaceous interlayers suggest volcanic eruptions occurred between 802 Ma and 789 Ma, providing age constraints for the Sukuluoke Formation at the top of the Silu Group. These calc-alkaline tuffs exhibit arc-related geochemical signatures, suggesting continental arc magmatism along the southwestern margin of the Tarim Craton. Detrital zircon provenance and sedimentary facies analyses reveal that proximal Tonian magmatic arc clasts contributed significantly to the basins, possibly sharing a common source with the volcanic tuff. These findings, along with regional magmatism, stratigraphic unconformities, and coeval metamorphism, collectively suggest a mid-Neoproterozoic assembly event involving subduction and collision. A plausible tectonic scenario involving subduction, collision, and subsequent rifting is proposed for the Neoproterozoic evolution of the southwestern Tarim Craton. This model serves as a preliminary framework that will require further geological constraints to refine the regional geological history.