Late Mesozoic intracontinental deformation and magmatism in the Chinese Tianshan and adjacent areas, Central Asia

Abstract

The Tianshan Range−Junggar Basin−Kalamaili Range system represents the southwestern Central Asian Orogenic Belt and is a natural laboratory for studying intracontinental deformation processes. Its current topography is a product of the far-field effects of the Cenozoic India-Asia collision. However, the Mesozoic topographic and tectonic evolution of the Tianshan and Kalamaili Ranges and their impacts on the Junggar Basin remain enigmatic due to the scarcity of data. Here, we present a comprehensive synthesis of sedimentological and geochronological data on these ranges and adjacent basins to reconstruct the intracontinental evolution from the Early Jurassic to the Early Cretaceous. Based on field observations and seismic profile analysis, we identified several unconformities within the late Mesozoic strata in the Tianshan Range and the Junggar Basin. Detrital zircon U-Pb dating results for Lower Jurassic to Lower Cretaceous sandstones of the eastern and southern Junggar Basin, with published paleocurrent data, reveal a complex intracontinental topographic evolution. Moreover, tuffaceous gravels and tuff samples yielded weighted mean zircon 206Pb/238U ages of 156.5 ± 3.2 Ma and 156.3 ± 2.2 Ma, respectively, which indicates the presence of contemporary magmatic activity. The deformation and magmatism mentioned above were possibly related to multi-plate convergence in East Asia during the late Mesozoic. This study provides new insights into the late Mesozoic tectonic-magmatic evolution of the Tianshan Range and its adjacent areas.

Detrital zircon U–Pb geochronology and Hf isotopes of Mesozoic through Cenozoic sandstones from the southern Junggar Basin, NW China: Implications for the provenances and uranium source

“…A new age group component of 140–170 Ma now accounts for 20–40% of the total zircon population (Figure 11f–h), and the source is probably associated with the ongoing Late Jurassic “Yanshanian” magmatic activities. Late Jurassic–Early Cretaceous tectonic activity induced intense uplift of the Tianshan Mountains and magmatic activity (Morin et al, 2018; Wang et al, 2022; Zhu, Wang, Cao, & Wang, 2020; Zhu, Wang, Lu, et al, 2020).…”

“…During the Early Jurassic through early Middle Jurassic, the boundary of the basin was at least near the southern edge of the Houxia area, which is now located in the intermontane region, and there was no obvious geographical separation at this time (Fang et al, 2005) and the source is probably associated with the ongoing Late Jurassic "Yanshanian" magmatic activities. Late Jurassic-Early Cretaceous tectonic activity induced intense uplift of the Tianshan Mountains and magmatic activity (Morin et al, 2018;Wang et al, 2022;Zhu, Wang, Cao, & Wang, 2020;Zhu, Wang, Lu, et al, 2020).…”

A re-evaluation of the Meso-Cenozoic thermo-tectonic evolution of Bogda Shan (Tian Shan, NW China) based on new basement and detrital apatite fission track thermochronology

“…Based on a summary of published detrital zircon U-Pb data and sedimentary analyses, it is suggested that the North Tianshan was the main source terrane for the sediments in the southern Junggar Basin during the Jurassic (e.g. Fang et al 2019;Wang et al 2022). Hence, the Late Triassic-Middle Jurassic AFT cooling ages were not only recorded by the basement rocks in the Bogda Shan (Supplementary Table S3), the neighbouring basins also received coeval thermochronological signals.…”

“…On the other hand, the Chinese Tianshan belt and neighbouring basins experienced varying degrees of deformation during the Cretaceous generally under a contractional setting (e.g. Zhu et al 2004Zhu et al , 2006Yang et al 2017;Wang et al 2022;He et al 2022aHe et al , 2022b. In the eastern and southern Junggar Basin, the Jurassic strata were deformed and folded as revealed by the seismic profile data (e.g.…”

“…Since late Palaeozoic-early Mesozoic thermochronological signals embedded in the basement rocks have been largely eroded by later tectonic events, current interpretations of the exhumation history of Bogda Shan rely heavily on sedimentological evidence (e.g. Fang et al 2019;Wang et al 2022 for recent comprehensive reviews).…”