Did you know that mountains grow at a relatively fast rate (a few mm each year) until the forces that form them are no longer active? Apparently that’s the case with the Andes Mountains which are one of the longest and highest mountain ranges in the world.
For millions of years the Andes grew slowly. Then all of a sudden, 10 – 6 million years ago things changed. Geologists at the University of Rochester in NY, led by professor Carmala Garzione, revealed that in the last 4 million years the Andes grew by as much as 2,500 meters. Furthermore, things are not about to stop.
Formed in the Jurassic period (150-200 milion years ago) as a result of plate tectonics processes which caused a large sheet of crust, the Nazca plate, they slid under the South American plate. What’s more,the Andes are still active.
This new discovery may suggest that the tectonic plates theory, which explains how mountains are formed (two tectonic plates pushing against each other), should be updated. The new “theory” was named delamination, and refers to denser rocks that can detach from the underside of the crust allowing the lighter crust to rise in sudden bursts.
Garzione and her colleagues are now trying to find out what were the effects of such a rapid growth of the Andes (and probably other mountains, too) on climate and the evolution of life on Earth.