The Jurassic-Cretaceous closure dynamics of the Bangong-Nujiang Tethyan Ocean provide pivotal constraints on the Tibetan Plateau’s collisional orogeny and crustal thickening. To rigorously constrain the subduction and closure processes of the Bangong-Nujiang Tethyan Ocean during the Jurassic-Cretaceous, this study employs systematic anisotropy of magnetic susceptibility (AMS) analysis. By investigating the relationship between the maximum principal compressive stress direction (inferred from magnetic of susceptibility ellipsoids) and the subduction dynamics of the Bangong-Nujiang Tethyan, we establish new structural deformation insights from the continuous Middle Jurassic-Late Cretaceous sedimentary sequences in the Linzhou Basin of the Lhasa Block. These findings provide critical constraints on the Jurassic-Cretaceous subduction evolution of the Bangong-Nujiang Tethyan Ocean. The Linzhou Basin, spanning from the Middle Jurassic Yeba Fm. to the Late Cretaceous Shexing Fm., experienced dual subduction dynamics: southward subduction of the Bangong-Nujiang Tethyan Ocean and northward subduction of the Yarlung-Zangbo Neo-Tethys Ocean. Crucially, the AMS data reveal that underlying strata preserved their primary deformation signatures without being overprinted by younger tectonic events. This implies that the AMS record faithfully reflects the contemporaneous tectonic stress field during the deposition and early deformation of each stratigraphic horizon. During the Middle-Late Jurassic, the Shiquanhe-Namco Ocean remained an open oceanic domain until its eventual closure in the Early Cretaceous. Consequently, the southward compressional stress regime documented in the Linzhou Basin during this interval likely reflects a composite tectonic signature, originating from the dual south subduction systems of both the Bangong-Nujiang Tethys Ocean and the Shiquanhe-Namco Ocean. Until the Early Cretaceous Takena Fm., the southward compression experienced by the Linzhou Basin was only related to the southward subduction of the Bangong- Nujiang Tethys Ocean. The Bangong-Nujiang Tethyan Ocean did not close during the Late Cretaceous Shexing Fm., but the subduction intensity was significantly reduced compared to the Early Cretaceous Takena Fm., indicating that the Bangong-Nujiang Tethyan Ocean tended to close.
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