Timing of major suture zones in North Xinjiang, China: Constraints from stitching plutons
“钉合岩体”与新疆北部主要缝合带的形成时限

This study introduces the concept of stitching pluton because a stitching pluton can provide an upper-age bound for the timing of an accretionary or a collisional event in orogens, with an emphasis on the geochronological constraints from the stitching plutons crosscutting major suture zones on the timing of accretionary and collisional events in North Xinjiang. A combination of the oldest stitching plutons and the youngest ophiolitic rocks within the major suture zones in North Xinjiang may tightly constrain the timing of these major suture zones. The Irtysh-Zaysan suture zone between the Altai terrane in the north and the Zharma-Saur magmatic arc in the south, the North Tian Shan suture zone between the Junggar terrane in the north and the Kazakhstan-Yili terrane in the south, and the South Tian Shan suture zone between the Kazakhstan-Yili terrane in the north and the Tarim craton in the south were formed during the Late Carboniferous, whereas the other ophiolite zones in East Junggar and West Junggar during the Early Carboniferous or earlier. The western Junggar accretionary complex was commonly crosscut by many Late Carboniferous stitching plutons, but it is unclear that these plutons were generated by either subduction-related or post-collisional magmatism during the Late Carboniferous so that more work needs to be done in the future in order to eliminate the uncertainty. The pre-existing data are in support of Late Paleozoic orogens, without evidence for Triassic collision, in North Xinjiang. Particularly, the stitching plutons within the South Tian Shan provide an upper-age bound for the timing of the South Tian Shan suture zone and strong evidence against the suspected Late Permian radiolarians from the Baleigong ophiolite, and they also help re-interpret the Triassic zircon U-Pb ages from the high and ultrahigh pressure metamorphic rocks within the suture zone.