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The height of mountain ranges reflects the balance between tectonic rock uplift, crustal strength and surface denudation. Tectonic deformation and surface denudation are interdependent, however, and feedback mechanisms-in particular, the potential link to climate-are subjects of intense debate1,2. Spatial variations in fluvial denudation rate caused by precipitation gradients are known to provide first-order controls on mountain range width, crustal deformation rates and rock uplift3,4. Moreover, limits to crustal strength5 are thought to constrain the maximum elevation of large continental plateaus, such as those in Tibet and the central Andes. There are indications that the general height of mountain ranges is also directly influenced by the extent of glaciation through an efficient denudation mechanism known as the glacial buzzsaw6-9. Here we use a global analysis of topography and show that variations in maximum mountain height correlate closely with climate-controlled gradients in snowline altitude for many high mountain ranges across orogenic ages and tectonic styles. With the aid of a numerical model, we further demonstrate how a combination of erosional destruction of topography above the snowline by glacier-sliding and commensurate isostatic landscape uplift caused by erosional unloading can explain observations of maximum mountain height by driving elevations towards an altitude window just below the snowline. The model thereby self-consistently produces the hypsometric signature of the glacial buzzsaw, and suggests that differences in the height of mountain ranges mainly reflect variations in local climate rather than tectonic forces.
Distinctive alpine landforms, such as broad 'U'-shaped, flat-floored valleys, hanging valleys, cirques, horns and knife-edged ridges (are?tes), are considered the fingerprints of glacial erosion. These glacial landforms exist in most of Earth's mountain chains, produced by present and past glaciers. A majority of these landforms are associated with pronounced topographic relief consisting of over-steepened valley sides, headwalls and near-orthogonal tributary junctions often occupied by spectacular waterfalls. Perhaps not surprisingly, glaciations have accordingly been assumed to increase average relief mainly by incising valley systems, leaving high elevation peaks and hillslopes almost unaffected, and producing significant isostatically driven peak uplift10.
However, it has recently been discovered that glaciated orogens in the Himalayas6, the Andes7, the Sierra Nevada (USA)11 and the Cascade Range8 hold a striking coincidence of snowline altitudes, glacier equilibrium line altitudes (ELA) and elevations with a high proportion of...