Jurassic and Eocene Paleomagnetism in the Western Tethyan Himalaya: Implications for the India‐Asia Collision

Abstract The Tethyan Himalaya (TH) represents the northernmost continental unit of the India Plate that collided with Asia in the Cenozoic, forming the Himalayan‐Tibetan orogen. Paleomagnetic studies on the TH can help to understand the timing, kinematics, and geodynamic evolution of the India‐Asia collision, though remagnetization poses challenges in obtaining reliable data. This study presents a paleomagnetic investigation of the Jurassic Samanasuk and Eocene Shekhan formations in the western TH. The Jurassic limestone exhibits single polarity with a mean characteristic remanent magnetization (ChRM) direction of D g / I g = 136.4°/−68.4° ( k = 6.1, α 95 = 16.9°, N = 15) before and D s / I s = 115.1°/−43.7° ( k = 29.5, α 95 = 7.2°, N = 15) after tilt correction, while the Shekhan Formation shows dual polarity with a mean ChRM direction of D g / I g = 268.2°/63.5° ( k = 9.4, α 95 = 19.1°, N = 8) before and D s / I s = 313.3°/41.4° ( k = 48.5, α 95 = 8.0°, N = 8) after tilt correction. Both formations yielded a positive fold test, showing a pre‐folding origin of the ChRM. Based on ChRM direction analyses, field observations, and previously reported petrographic and geochemical studies, we conclude that the Samanasuk Formation was remagnetized around 40 Ma by chemical remanent magnetization, providing a paleolatitude of 25.9°N ± 8.3°. In contrast, the Shekhan Formation retains its primary remanence, likely insulated from remagnetization by thick shale intercalations, providing a paleolatitude of 24.2°N ± 6.9° at 54–51 Ma. This indicates a paleolatitudinal difference of 12.6° ± 5.5° between the TH and the India Craton around 50 Ma, which likely reflects a multistage India‐Asia collision model.