Document Type
Article
Department or Administrative Unit
Geological Sciences
Publication Date
12-30-2011
Abstract
Differences in the timing of glacial advances, which are commonly attributed to climatic changes, can be due to variations in valley topography. Cosmogenic 10Be dates from 24 glacial moraine boulders in 5 valleys define two age populations, late-glacial and early Holocene. Moraine ages correlate with paleoglacier valley hypsometries. Moraines in valleys with lower maximum altitudes date to the lateglacial, whereas those in valleys with higher maximum altitudes are early Holocene. Two valleys with similar equilibrium-line altitudes (ELAs), but contrasting ages, are < 5 km apart and share the same aspect, such that spatial differences in climate can be excluded. A glacial mass-balance cellular automata model of these two neighboring valleys predicts that change from a cooler-drier to warmer-wetter climate (as at the Holocene onset) would lead to the glacier in the higher altitude catchment advancing, while the lower one retreats or disappears, even though the ELA only shifted by ~120 m.
Recommended Citation
Pratt-Sitaula, B., D. W. Burbank, A. M. Heimsath, N. F. Humphrey, M. Oskin, and J. Putkonen (2011), Topographic control of asynchronous glacial advances: A case study from Annapurna, Nepal, Geophys. Res. Lett., 38, L24502, doi:10.1029/2011GL049940.
Journal
Geophysical Research Letters
Rights
Copyright 2011 by the American Geophysical Union.
Comments
This article was originally published in Geophysical Research Letters. The full-text article from the publisher can be found here.