Climate‐Driven Topographic Asymmetry Enhanced by Glaciers: Implications for Drainage Reorganization in Glacial Landscapes.

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 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. Plain Language Summary: In mountainous regions, the amount of rain, snow, and ice that falls and builds up often varies from one side of a mountain to the other. Over thousands to millions of years, these variations can make the length and steepness of the mountain sides differ, too. When glaciers form during ice ages, they can make this asymmetry in the topography even more pronounced. Our study looks at how glaciers affect the landscape and how glaciers and landscapes change in different climate conditions. Using a computer model, we discovered that the landscape becomes even more asymmetric when it is shaped by glaciers compared to when it is shaped by rivers. Our findings suggest that glaciers can cause landscapes to constantly change between ice ages. Key Points: We quantify topographic asymmetry caused by asymmetric glaciationGlacial erosion causes greater topographic asymmetry than fluvial erosion all else equalGlacial‐interglacial cycles can cause divide migration [ABSTRACT FROM AUTHOR]