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

作者：Bingshuai Li, Maodu Yan, Weilin Zhang, Jinbo Zan, Tao Zhang, Xiaomin Fang · 发表于：Geological Society of America Bulletin · 年份：2025 · DOI：10.1130/b38587.1 · 研究领域：Geological and Geochemical Analysis、Geomagnetism and Paleomagnetism Studies、High-pressure geophysics and materials

Abstract 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 e...