Abstract:
The Beishan orogenic belt is located in the middle of the southern margin of the Central Asian orogenic belt, and is at the key tectonic position of the east−west tectonic connection. In recent years, the tectonic evolution of Beishan has become a research focus, and important progress has been made in the aspects of orogenic basement, magmatism, ophiolitic mélanges, sedimentation, and deformation. This paper focuses on recent advances and summarizes the basic characteristics of each tectonic unit of Beishan, particularly the spatial−temporal distribution of magmatism and ophiolitic mélanges, and discusses the accretionary processes of Beishan. The Precambrian magmatic records are scattered Mesoproterozoic (Ca. 1.4 Ga) and Neoproterozoic (Ca. 0.9~0.8 Ga) gneissic granitoids, and there is no large−scale Precambrian basement in Beishan. Continuous magmatism developed from Early Paleozoic to Early Mesozoic across Beishan. The ophiolitic mélanges changed from Cambrian–Ordovician in the middle to Carboniferous–Permian in the north and south, and the final suture zone is located in the Liuyuan–Houhongquan area in southern Beishan. The ages of mafic rocks and the youngest sedimentary matrix jointly define the age for terminal accretion as the Middle–Late Triassic. Beishan was located at the margin of supercontinent from the Mesoproterozoic, and then experienced long−term accretion in Neoproterozoic and Paleozoic, and terminated accretionary orogeny and shifted to intracontinental evolution in Triassic. The accretion of mantle−derived arc magmatism and growth of accretionary wedges are of great significance to continental growth during the long−lived accretionary orogenesis.