Climate-driven topographic asymmetry enhanced by glaciers: Implication
for drainage reorganization in glacial landscapes
Abstract
Climate contrasts across drainage divides, such as orographic
precipitation, are ubiquitous in mountain ranges, and as a result,
mountain topography is often asymmetric. During glacial periods, these
climate gradients can generate asymmetric glaciation, which may modify
topographic asymmetry and drive divide migration during
glacial-interglacial cycles. Here, we quantify topographic asymmetry
caused by asymmetric glaciation and its sensitivity to different climate
scenarios. Using an analytical model of a steady-state glacial profile,
we find that the degree of topographic asymmetry is primarily controlled
by differences in the Equilibrium Line Altitude (ELA) across the divide.
Our results show that glacial erosion can respond to the same climate
asymmetry differently than fluvial erosion. When there are precipitation
differences across the divide, glacial erosion produces greater
topographic asymmetry than fluvial erosion, all else equal. These
findings suggest that glaciations may promote drainage reorganization
and landscape transience in intermittently glaciated mountain ranges.