Tectonic evolution of Tianshan-Bogda-Kelameili mountains, clastic wedge basin infill and chronostratigraphic divisions in the source-to-sink systems of Permian-Jurassic, southern Junggar Basin

Abstract

Continuous Paleozoic-Mesozoic sediment records within Junggar Basin, Northwestern China, provide details on tectonic evolution of the surrounding Tianshan, Bogda, and Kelameili orogenic belts. We compiled 5250 zircon U-Pb ages from 58 samples (602 new and 4648 published ages) and integrated with published paleo-current directions, paleo-geography, and well core data to reconstruct the uplift timing and provenance for source-to-sink systems of southern Junggar Basin from Permian to Jurassic. This reconstruction strongly suggests that the Kelameili area, middle Southern Tianshan, and western Northern Tianshan had been uplifted before the Permian. However, the uplift of southern Central Tianshan, eastern Bogda, and western Bogda initiated in middle Permian, late Permian, and early Jurassic, respectively. In addition, maximum depositional age calculated from youngest zircon U-Pb ages modes provides new constrains on the chronostratigraphy of southern Junggar Basin, including the Jingjingzigou Fm., Karamay Fm., Haojiagou Fm., Shirenzigou Fm., Lucaogou Fm., Toutunhe Fm., and Qigu Fm. This study provides a basis for a larger reconstruction of the stratigraphic and tectono-sedimentary evolution in response to the tectonic interactions between southern Junggar Basin and surrounding ranges during Permian through Jurassic times.