Geochronology, geochemistry and tectonic setting of Middle Permian ophiolites in Yaduwula region, Inner Mongolia

The Solonker Suture records the termination of the Central Asian Orogenic Belt (CAOB), but its eastward extension beneath the Songliao Basin has not been clear. The Yaduwula ophiolite is one of the significant fragments within the Solonker Suture. LA–ICP–MS U–Pb dating of zircon grains from metamorphic basalts yield ages of 263±4 Ma and 274±3 Ma, constraining the Yaduwula ophiolite in the late Cisuralian and Guadalupian age. This might indicate that the subduction of Paleo-Asian Ocean continued until at least the Guadalupian (middle Permian). Geochemical analysis of the metamorphic basalts revealed enrichment in large ion lithophile elements (LILEs) and depletion in high field strength elements (HFSEs) and show the characteristics of a supra-subduction zone. The results provide the evidence for the closure time of the Paleo-Asian Ocean after the middle Permian and also suggest that the Yaduwula ophiolite may be considered the eastern extension of Solonker Suture. Our study provides further insights on the evolution of the southeastern Central Asian Orogenic Belt.