Earth Sciences

Study: Mountain Ranges Rise Faster Than Expected

DATA MINDING: Garzione pioneered a new method for measuring ancient mountain elevations.

Scientists will have to re-evaluate their understanding of the tectonic process behind the world’s highest mountain ranges, thanks to work by Carmala Garzione, an assistant professor of earth and environmental science. In two separate papers last spring—one in Science and one in Earth and Planetary Science Letters—Garzione reported evidence that mountain ranges rise to their height in as little as 2 million years—several times faster than geologists have always thought.

For her research, Garzione pioneered a new method of evaluating the minerals in sediment that’s carried down slopes and that collects at the bases of mountains as they form. Her recent work concentrated on the Bolivian Altiplano, a high-elevation basin in the Andes Mountains in South America, where she took samples of sedimentary rock that had accumulated between 12 million and 5 million years ago.

“These results really change the paradigm of understanding of how mountain belts grow,” she says. “We’ve always assumed that the folding and faulting in the upper crust produced high-elevation mountains. Now we have data on ancient mountain elevation that shows something else is responsible for the mountains’ uplift.”