Major fault traces (white lines) and suture zones (black dash lines) are obtained from the HimaTibetMap-1.1 data set69. Yellow and magenta filled circles mark two different episodes of magmatism distributions46,53. White arrows indicate motions of different tectonic units relative to stable Eurasia2,70. The thick red dashed line delineates the −4% contour of shear wave speed anomalies (δlnVS) at a depth of 80 km beneath Northern Tibet, the thick blue line denotes the 2% contour of δlnVS at a depth of 175 km and the thick blue dashed line represents the 2% contour of δlnVS at a depth of 350 km. All the contour lines are extracted from Fig. 2a–c. The abbreviations of suture zones, IYS, BNS, JS and AKMS are defined in Fig. 4.