Crustal structures inferred from Bouguer gravity anomalies in the Altai Orogen, Junggar Basin, Tianshan Orogen, and Tarim Basin

Based on a Bouguer gravity dataset, we investigate the crustal structures in the region across the Chinese Altai Orogen, Junggar Basin, Tianshan Orogen, and Tarim Basin. Combined with magnetic anomalies and crustal thickness data, the Bouguer gravity anomalies are used to identify regional faults and to infer the basement composition in the Junggar Basin. The regional fault distribution shows that multiple tectonic detachment surfaces may exist in the crust and upper mantle of the Chinese Altai Orogen. The mountain roots mentioned in previous studies may not exist in the Tianshan Orogen, where lower-crustal materials have likely been incorporated into the uppermost mantle. The Tarim Basin consists of Archaean-Palaeoproterozoic crystalline basement and Meso-Neoproterozoic metamorphic basement with high Bouguer gravity anomalies. The tectonic sutures can be inferred from the lateral variation of the Bouguer gravity and improve our understanding of the evolution of the southwestern Central Asian Orogenic Belt.