They are very remote and have never been surveyed on the ground. There is not even aerial photography. Isacks is chair of the Department of Geological Sciences and director of the Institute for the Study of the Continents at Cornell. Much of the Cornell work will focus on the Altiplano, a huge plateau surrounded by higher peaks and spreading through northern Argentina, western Bolivia and southern Peru. Being able to look at the topographic detail along the sides of it may go a long way.
Geologists do know, in a general way, how the Andes got there.
Some 200 million years ago, the eastern edge of the Nazca plate began shoving its way under the western edge of the South American plate, which makes up the continent itself and part of the South Atlantic Ocean floor. The land above was lifted and squeezed. For much of the time, the effects were confined to what are now the coastal regions of Chile and Peru. Then, during the last 20 million years, the effects occurred over a much wider zone. Like a tablecloth shoved by a heavy platter, the crust folded and began thrusting up mountains so sharply that there is a drop of 40,000 feet from the western edge of the Andes to the Peru-Chile trench in the Pacific Ocean over a horizontal distance of only 200 miles.