Cenozoic paleomagnetic rotations along the West Kunlun Mountains (Central Asia) and tectonic implications for the evolution of the Pamir salient

The Pamir salient in the western Himalayan syntaxis of Central Asia represents a key region for understanding intracontinental deformation during the Indian−Asian collision. However, its kinematic processes remain poorly understood, particularly along its eastern flank. Here, we present a detailed paleomagnetic rotation study on the Paleogene to Neogene sediments at Sanju in the eastern segment of the Western Kunlun thrust belt, aiming to provide new insights into the deformation of the Pamir salient. Detailed thermal demagnetizations successfully isolated 400 characteristic remanent magnetizations (ChRMs) from 45 sites. These ChRMs pass fold, reversal, and conglomerate tests, indicating that these magnetizations are of primary origin. Paleomagnetic results reveal a significant (∼35.6° ± 12.3°) clockwise rotation during ca. 39−33 Ma at Sanju, with negligible rotation thereafter. Together with other paleomagnetic results along the Western Kunlun thrust belt, the obvious clockwise rotations are interpreted as local rotations that are likely associated with the far-field effects of the Indian−Asian collision. Notably, the Western Kunlun thrust belt experienced an additional obvious (10°−15°) clockwise rotation, with the pivot centered around Sanju after ca. 3 Ma, suggesting at least ∼24.7−37.5 km of crustal shortening at the western tip of the Western Kunlun thrust belt or the northward indentation of the Pamir salient. Integrating these findings with other geological evidence around the Pamir salient, we propose that asymmetric radial thrusting or oroclinal bending with conjugate rotations along the two flanks of the Pamir salient served as the primary mechanism for accommodating the continuous northward indentation of the Indian plate since the late Neogene. This asymmetry is predominantly attributed to the heterogeneity of the upper crust or the lithosphere of the Tajik and Tarim basins.