Bhumichula plateau: A remnant high-elevation low-relief surface in the Himalayan thrust belt of western Nepal

The Himalaya is known for dramatically rugged landscapes including the highest mountains in world. However, there a limited understanding of timing attainment high elevation and relief formation, especially Nepalese Himalaya. Anomalous high-elevation low-relief (HELR) surfaces, which exhibit geomorphic antiquity are possibly remnants formerly widespread paleosurfaces, provide unique opportunity to assess regional Bhumichula plateau one such HELR surface (4300−4800 m) western Himalayan fold-thrust belt. situated Dadeldhura klippe (also called Karnali klippe), an outlier Greater Sequence high-grade metasedimentary/igneous rocks surrounded by structurally underlying Lesser low-grade metasedimentary rocks. We origin combining geological relationships zircon apatite (U-Th-Sm)/He fission track thermochronologic ages. truncates pervasive west-southwestward dipping foliations, indicating that it post-dates tilting hanging wall Main Central thrust above duplex. This suggests originated at erosional beveling thickened, uplifted crust. Exhumation through ∼180−60 °C thermal window occurred during middle Miocene samples on between late along Tila River, bounds north flank plateau. Cooling ages River consistent with exhumation generated early emplacement (Dadeldhura) sheet, Ramgarh emplacement, growth most recent middle-late took place as its northward flowing tributaries incised upstream, remnant more extensive paleolandscape. Alpine glaciation lowered surface, preservation may owe relatively durable lithology, gentle structural relief, range rainier