Would Alaska’s Mount Denali – the highest peak in the US – be as tall if it was situated on the equator instead? Might the Himalayas be even taller if an ice age took hold? Every mountain range is sculpted by rain and wind, but some mountain belts are also sliced by glaciers, producing the classic horn-shaped peaks, knife-edge ridges and amphitheatre-like valleys, known as “cirques”. A new study shows that by lightening the load, glacial erosion helps to create higher mountains than might otherwise be expected.
Jörg Robl, from the University of Salzburg in Austria, and colleagues analysed 16,000 of the world’s highest mountains, comparing their overall height, their steepness and the thickness of the underlying crust supporting them. They found that some of the steepest mountains are found at the highest latitudes, where glacial sculpting predominates. And because glaciers create such “skinny” mountains, they show that the underlying crust (like icebergs, mountains have extensive crustal roots) does not need to be as thick as it would for a non-glacial peak.
Which suggests that all things being equal, Denali wouldn’t be as tall if it had popped up in Mexico instead of Alaska. Meanwhile, the Himalayas might have a few 9,000-metre peaks in an ice-house world …
