Paleomagnetic constraints on Paleogene-Neogene rotation and paleo-stress in the northern Qaidam Basin

Knowing the rotation and paleo-stress history in Qaidam Basin is a fundamental parameter to quantify mechanism of intracontinental deformation Tibetan Plateau. However, few studies have been conducted on tectonic stress evolution over long timescales Basin. Here, we report new magnetic declination anisotropy susceptibility (AMS) from ∼52–7 Ma sequence fluvial lacustrine sediments Dahonggou (DHG) section northern The revealed that underwent clockwise 25.1° ±8.6° during ∼33–17 Ma, followed by counterclockwise 16.9°±6.8° ∼17–13.5 Ma. AMS results showed “earliest deformation” fabrics were interrupted “pencil structure” intervals ∼52–45 ∼21–15 interruption, synchronous with marked deceleration India-Asia convergence rate, indicates pulse strong compressive stress. In addition, documented transition direction S-N SW-NE at ∼15 suggesting kinematic shift northeastern TP. Our constraints support two-stage Altyn Tagh Fault (ATF). fast-rate slip motion ATF early Oligocene caused Basin; second stage enhanced thrusting since middle Miocene extensive crustal shortening dispersive NW-trending folds faults