Denudation of Small Alpine Basins, Nanga Parbat Himalaya, Pakistan

Abstract

Thirty-three debris fans and five small alpine basins on the south side of the rapidly uplifting Nanga Parbat Himalaya of northern Pakistan were assessed to determine how much alpine processes contribute to the overall denudation of the massif. A high-resolution digital elevation model was used to measure the volume of the small alpine fans and a few basins in the Rupal valley. These volumetric estimates, coupled with time-constraining dates from cosmogenic-nuclides of glacially exposed rocks and infrared-stimulated luminescence of sediments, indicate that estimated average denudation rates in these systems have been ~2 mm yr⁻¹ over the past 4600 to 6000 yr since the last major deglaciation. This is similar to other estimates of rates of denudation in the Himalaya.