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Cosmogenic radionuclides (CRN) such as beryllium-10 (10Be) are important tools for tracking erosion processes at the Earth’s surface. However, they are difficult to employ where sediment remains temporarily stored for millions of years and is later re-eroded. We call this sediment recycling. We quantified sediment recycling in the Mohand Range, at the foothills of the northwestern Himalaya, based on the present-day CRN concentration in fluvial sediments recycled from tectonically uplifted older foreland deposits. We do this by simulating how the CRN concentrations change as sediment is first eroded in the Himalayan source region, deposited in the foreland, and eventually eroded again. By comparing modeled concentrations with the measured values, we show that the erosion rates in the Mohand Range vary from 0.42 ± 0.03 to 4.92 ± 0.34 mm yr-1, corresponding to ca. 2.0 megatons of sediment recycling from this range to the downstream Yamuna foreland. The low 10Be concentration in recycled sediment, compared to the sediment eroded from the high Himalaya, implies that if high Himalayan sediments are admixed with recycled material, the inversion of these mixed sediment 10Be concentrations into erosion rates may lead to higher than the actual erosion rates in the high Himalaya. |