QUANTIFYING THE GLACIAL BUZZSAW WITHIN AN ARID MOUNTAIN RANGE: LADAKH, NORTHWESTERN HIMALAYA

Cosmogenic ¹⁰Be measurements of both bedrock and basin denudation reveal strong topographic-climatic control on erosion within the Ladakh Range of northwestern India. Bedrock weathering rates, extremely slow below the contemporary equilibrium line altitude, increase by an order of magnitude at the high-elevation range divide. Along the southern slope of the Range south of the range divide, rates of ridge crest summit lowering vary from 0.02±0.03 m/Myr to 0.7±0.09 m/Myr, whereas rates of range divide summit lowering vary from 4.97±0.45 m/Myr to 13.13±1.17 m/Myr. Long-term denudation rates of nonglaciated basins are the lowest yet reported. Accelerated glacial and periglacial erosion near the range divide drives a glacial- or frost-buzzsaw mechanism in this region that works to selectively destroy high topography. The actively-eroding glacial landscape stands in stark contrast to hillslopes at lower elevations, which have achieved long-term, near equilibrium conditions and may represent extant Pliocene or older landscapes.