Climate change carved canyons in Andes

Erosion came thanks to cooling and more rain, not tectonic activity

CARVING CANYONS  Climate change that brought more rain to the northeastern Andean Plateau triggered the erosion that carved the  area’s canyons (Peru’s Rio San Gaban canyon shown), geologists report.

R.  Lease

The onset of a cooler climate 4 million years ago — rather than tectonics — helped carve deep canyons in the Andes, geologists report in the Aug.