Once home to the powerful Inca Empire, the spectacular vistas and
canyons of the South American Andes are now a favorite to mountain
bikers, climbers and other tourists looking for an adventure. This true
color image of the Central Andes and surrounding landscape was acquired
by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying
aboard NASAs Terra spacecraft. The dark green area to the right of the
brown mountains are the Gran Chaco planes, which consist mostly of
alluvial fans and wetlands. To the west is the Pacific Ocean.
In the upper half of this image, the Andes are formed by two distinct
mountain ranges that appear as darker reddish-brown bands running
northwest to southeast. Between the two ranges, shown in a lighter
brown, sits the Altiplano plateau, which spans southern Peru and
northern Bolivia. The plateau sits at 3660 meters (12,000 feet) and is covered in
mazelike canyons, marshlands and lakes. The largest of the lakesLake
Titticacacan be seen as the dark blue patch in southern Peru. The two
mountain ranges supporting the plateau eventually come together along
the border of Argentina and Chile to form one continuous range.
The Andes have been forming over the past 170 million years as the Nazca
Plate lying under the Pacific Ocean has forced its way under the South
American Plate and pushed up its western edge. The subduction of one
plate under the other has given rise to a number of volcanoes that dot
the western edge of the mountain range. Earthquakes are also very common
in this region.