The Wilson cycle of the Sumdo Paleo-Tethys Ocean and linkages to the spatial-temporal evolution of the Lhasa terrane

The Tethyan tectonic domain preserves crucial records of repeated ocean-basin opening and closure, as well as continental accretion, thereby offering a fundamental window into the evolution of global plate tectonics. The Sumdo Paleo-Tethys Ocean (SPTO) is widely recognized as a significant component of the Paleo-Tethys system, and its evolution provides essential constraints on the rifting, drifting, and subsequent convergence history of the Lhasa Terrane. Despite significant advances in petrological, geochronological, geochemical, and structural investigations, fundamental uncertainties and controversies remain regarding the oceanic nature, evolutionary history, and geodynamic mechanisms of the SPTO. In this study, we synthesize Late Paleozoic–Early Mesozoic tectonic, magmatic, sedimentary, and metamorphic records from the Tangjia–Sumdo suture zone, together with available paleomagnetic and paleontological data, to reconstruct the evolution of the SPTO from its initial opening to final closure. Our integrated dataset indicates that the SPTO was a restricted oceanic basin within the eastern Lhasa Terrane. It opened during the Late Devonian–Early Carboniferous, underwent sustained seafloor spreading and progressive maturation during the Late Carboniferous–Permian, and developed an oceanic plateau in response to Middle–Late Permian mantle-plume activity. Subsequently, the SPTO subducted northward beneath the North Lhasa subterrane from the Early Permian to the early Late Triassic and ultimately closed during the Late Triassic–Early Jurassic, marking the transition from oceanic subduction to syn - and post-collisional tectonics. This was followed by a major tectonic reorganization in the Early Jurassic, when the eastern Lhasa Terrane shifted from a Paleo-Tethyan collisional regime to a Neo-Tethyan subduction-dominated active continental margin, thereby terminating the Wilson-cycle evolution of the SPTO. We further link SPTO evolution to the rifting and subsequent drifting of the Lhasa Terrane from Gondwana, identifying two major rifting episodes: (1) opening of the SPTO, which drove rifting of the eastern North Lhasa subterrane, and (2) opening of the Neo-Tethys Ocean, which drove rifting of the South Lhasa subterrane. Collectively, these results refine the tectono-magmatic evolution of the SPTO and the Lhasa Terrane. By integrating our results with previous studies of the Paleo-, Meso-, and Neo-Tethys oceans, we establish a linked Wilson-cycle framework that elucidates the cascade-style transfer of tectonic forcing and the progressive northward propagation of one-way microcontinental convergence from Gondwana to Asia.