Paleomagnetism and Geochronology of the Late Jurassic Volcanic Rocks From the Westernmost Lhasa Terrane: Insights Into the Final Closure of the Meso‐Tethys Ocean

Abstract

The closure of the Meso‐Tethys Ocean is crucial to understanding the global evolution of the Tibetan Plateau prior to the India‐Asia collision and its influence on the environment and climate. Nonetheless, large uncertainties exist regarding the process due to the scarcity of reliable Late Jurassic paleomagnetic results. Here we present a combined paleomagnetic and geochronologic study on the ca. 147 Ma Zenong Group volcanic rocks in the westernmost Lhasa terrane. We obtained a well‐dated high‐quality paleopole at 63.0°N, 304.9°E with N = 20 sites, K = 29.9, and A ₉₅  = 6.1°, yielding a paleolatitude of 11.9 ± 6.1°N for the sampling area. The primary origin of the magnetization is supported by positive fold and reversal tests, with the statistical distribution consistent with the expected geomagnetic paleosecular variation. This new paleomagnetic result permits reconstructing the northward trajectory of the Lhasa terrane from the Southern Hemispherical paleolatitude toward Eurasia. Direct comparison with the pre‐collisional paleolatitude of the Qiangtang terrane demonstrates that the western part of the Meso‐Tethys Ocean remained open at ca. 147 Ma. Furthermore, by integrating our results with other reliable Late Triassic to Early Cretaceous paleomagnetic data sets from the Lhasa and Qiangtang terranes, together with regional geological evidence, the comparative results reveal that the final closure of the Meso‐Tethys Ocean occurred during ca. 140–130 Ma in the western part.