| The study of the subduction-collision orogeny timescale of the Jinshajiang orogenic belt is crucial for understanding the evolution of the eastern Paleo-Tethys orogen. It provides an accurate geotectonic background and insights into the Indosinian porphyry-skarn metallogenic system (such as the Yungla copper deposit) in the Jinshajiang orogenic belt. This study selects the ductile shear zone of the Yangla Xualong Hydropower Station in the middle section of the Jinsha River suture zone to carry out field investigation and microstructural kinematic analysis and geometric analysis. In addition, study utilizes LA-ICP MS U-Pb dating of zircon from granite and granodiorite and as well as 40Ar/39Ar isotopic thermochronology on biotite methods to determine the magmatic emplacement and metamorphic deformation in this ductile shear zone. The results show that the ductile shear zone of the Yangla Xualong Hydropower Station trends NE-SW, with right-lateral strike-slip characteristics indicated by field rotating ellipsoids and microscopic S-C fabrics. Granitic gneiss and undeformed Jiaren Granodiorite yielded zircon 206Pb/238Uwith crystallization ages 285Ma and 226.4Ma,respectively. In addition, biotite 40Ar/39Arisotopic metamorphic deformation plateau age of 223.75 ± 2.18Ma was obtained. It is concluded that the middle section of the Jinsha River orogenic belt has experienced the evolution process of rift basin (D), ocean basin expansion (C1-P1), oceanic crust expansion-subduction (283-279 Ma), collisional orogeny (269-259 Ma), late collisional extensional orogeny (223-231 Ma) and post-collision (215-200 Ma). Among them, the metamorphic-deformation age of the Xulong ductile shear zone is the Late Triassic, which is the product of the late collisional extrusion-extensional tectonic transition stage of the land-land collisional orogenic belt. |