Megathrust Heterogeneity, Crustal Accretion, and a Topographic Embayment in the Western Nepal Himalaya: Insights From the Inversion of Thermochronological Data

Between 81°30ʹE and 83°E, the Himalayan range's “perfect” arcuate shape is interrupted by an embayment. We hypothesize that thrust geometry duplexing along megathrust at midlower-crustal depths play a leading role in growth of embayment as well southern margin Tibetan plateau. To test this hypothesis, we conducted thermokinematic modeling published thermochronologic data from topographic structural western Nepal Himalaya to investigate three-dimensional kinematics depths. Models can best reproduce observed cooling ages suggest described two ramps connected long flat extends further north than segments east west. These models high-slope zone lies above foreland limb antiformal crustal accretion on with lateral oblique The may have initiated ca. 10 Ma. This process controlled along-strike variation Himalayan-plateau therefore development Finally, analyze geological morphologic features propose evolution model which landscape drainage systems across central-western evolve response depth megathrust. Our work highlights importance different orogenic-wedge midlower determines location plateau edge.