Abstract Comprehension of the ophiolitic mélange plays a key role in the tectonic reconstruction of an ancient orogenic belt in terms of plate tectonics. The tectonic nature of the NNW‐trending southern Jinshajiang ophiolitic mélange is still controversial. This study reports the results of a field study and new geochronological and geochemical data that enable the identification of the Zhongdian continental back‐arc basin. The basin was filled with a flysch succession and at least two horizons of pillow basalt from 267 to 254 Ma. The inversion of the back‐arc basin was completed in a short period of one million years (254‒253 Ma), which has led to the development of overturned folds of the flysch succession and a latest Permian to Early Triassic back‐arc foreland basin in front of the folded belt. The formation and inversion of the Zhongdian back‐arc basin is suggested to have been caused by rollback and subsequent break‐off of the subducted oceanic slab. During the inversion, the crust shortening occurred predominantly in the back‐arc basin, while the weakly deformed southwestern shoulder of the back‐arc basin has been shifted north‐eastward for ∼30 km. The formation process of the Zhongdian back‐arc basin is comparable to that of a typical continental rift system, the asymmetric architecture of which has mostly been inherited by the structures formed during the basin inversion. The short‐lived Zhongdian back‐arc basin likely marks the southernmost, immature termination of the southern Jinshajiang Ocean.
Xin et al. (Wed,) studied this question.