Wind has big impact in shaping arid South American canyons

The beauty of a canyon is principally the artful work of that masterful sculptor, the river. Rivers wouldn’t exist, obviously, without gravity, which also brings material down from the canyon walls. Various types of weathering—reducing rock to loose sediment—also do their part to make the river’s work easier. But there’s another force typically left off the acknowledgements list at the canyon awards that might deserve to be there—wind.

In arid places, wind erosion plays an important role, but its effectiveness is limited. When you come across a feature as dramatic as a canyon, you can be sure water put it there. Wind’s contribution has generally been considered minor. Jonathan Perkins and Noah Finnegan of the University of California Santa Cruz, and Oregon State’s Shanaka de Silva found a way to put that notion to the test.

Where you find water, you can generally find wind, too, so it’s a challenge to tease apart their effects. Constructing an experiment and waiting a million years for clear results isn’t a proposal likely to garner funding. But on the dry western slope of the Andes in northern Chile, the researchers found a natural experiment that conveniently started four million years ago.