Magnetostratigraphy of sediments from the Yumu Shan, Hexi Corridor and its implications regarding the Late Cenozoic uplift of the NE Tibetan Plateau

The Yumu Shan, located on the northernmost margin of the North Qilian Shan, contributes key information for deciphering the deformation and uplift of the NE Tibetan Plateau. This paper presents magnetostratigraphic results from Late Cenozoic sediments in the Yumu section of the northwestern Yumu Shan. The upper Shulehe Fm., Yumen Conglomerates Fm., and Jiuquan Gravels Fm., were deposited before ∼5.23 Ma, during the periods ∼3.58 to perhaps ∼1.77 Ma, and after ∼0.8 Ma, respectively. Four significant tectonic episodes occurred at ∼5.89 Ma, ∼3.58 Ma, during ∼2.88–2.58 Ma, and ∼0.9–0.8 Ma, based on sedimentation, magnetic susceptibility and angular unconformities. Being synchronous with tectonic activity throughout the NE Tibetan Plateau, these tectonic ages do not support the northward growth model for the NE Tibetan Plateau during the Late Cenozoic.