An intracontinental orogen exhumed by basement-slice imbrication in the Longmenshan Thrust Belt of the Eastern Tibetan Plateau

Abstract The Longmenshan Thrust Belt in Eastern Tibet resulted from a Mesozoic orogeny and Cenozoic reworking. It is generally believed that the tectonics along are mostly inherited Mesozoic. Reconstructing of therefore important for understanding its evolutionary history. On basis detailed structural analysis, we recognized Main Central Boundary divides into Southeastern Zone Northwestern Zone. Both zones underwent main D1 event characterized by D1E top-to-the-SE thrusting D1W top-to-the-NW/N In Zone, D2 normal faulting cuts structures developed NW boundary basement complexes. Newly obtained previous geochronological data indicate events occurred synchronously at ca. 224–219 Ma, was episodically activated 166–160 141–120 81–47 27–25 Ma. Episodic top-to-the-NW northwestern southeastern boundaries complexes, respectively, leads us to propose slices were imbricated SE during Late Jurassic–Early Cretaceous Cretaceous–earliest Paleocene. amphibolite facies metamorphic rocks above complexes recorded fast exhumation Cretaceous. We early northwestward underthrusting crustal “weak zone” responsible double-vergent metamorphism. Subsequent basement-slice imbrications reworked exhumed rocks. Our results highlight importance imbrication formation reworking intracontinental Tibet.