Two tectonostratigraphic concerns on the Late Paleozoic Tianshan tectonic complex were addressed in this study: 1) the stratigraphic succession of the Bayingou ophilite mélange; and 2) the timing of tectonic accretion of the Siberian craton in the Aiweiergou area by integrating the relevant data of stratigraphy, palaeontology, tectonopaleogeography and tectonopaleobiogeography. The authors considered that this unconformity indicates the closure of the