The temporal and spatial framework and its tectonic evolution of the Jinsha River arc-basin system, Southwest China

As the important part of the Sanjiang archipelagic arc-basin systems in southwest China, the tectonic evolution of the Jinsha River arc-basin system is of great significance to understanding the spatial-temporal pattern of Paleo-Tethys archipelagic arc-basin systems. In the light of the new geological survey data, research results and analysis data, this paper systematically summarizes the material composition and tectonic characteristics of different tectonic units of Jinsha River arc-basin system, and discuss the tectonic evolution process and its effect on controlling volcanogenic massive sulfide (VMS) deposits. Jinsha River Ocean mainly developed during the Late Silurian to Permian, and the ancient oceanic mantle was affected by the early subduction zone which is enriched in material formed in back-arc basin environment. As a complex epicontinental arc, Jomda-Deqen-Weixi continental margin arc has experienced four evolutionary stages, including subduction stage (300-260 Ma), the early collision convergence stage(255-250Ma), syn-collision extension stage (249-237Ma) and late collision orogenesis stage (236-212Ma), resulting in the formation of various types of magmatic activities and basins. High-pressure metamorphic belts such as Gonjo eclogite and Weixi retrograde eclogite have been recently recognized in Jinsha River suture zone, and provided key evidence for restoring the complex evolution of subduction-collision orogeny of Jinsha River Tethys. The new findings combined with the regional geological data, the evolutionary processes of the Jinsha River arc-basin system are constructed, mainly including the Late Silurian to Early Permian back-arc ocean basin expansion stage,the Late Early Permian to the Late Permian oceanic crust subduction stage,the Early Triassic to the Late Triassic arc-continental collision orogeny and basin-mountain conversion stage and the late Late Triassic post-collision intra-continental orogeny to intra-continental convergence-strike-slip transition stage. Each stage has controlled different types of VMS deposits.