The Andes and the American Cordillera

The Andes form the longest continental mountain chain on Earth, running some 7,000 kilometers along the western edge of South America from Venezuela and Colombia in the north to Tierra del Fuego in the south, part of the broader American Cordillera that continues through Central America and North America's Rockies. Unlike the Himalayas, the Andes result from ongoing oceanic-continental subduction: the Nazca Plate, and the Antarctic Plate farther south, are being driven beneath the South American Plate, generating the melting, volcanism, and crustal thickening that built the range across the Mesozoic and Cenozoic eras, with the most rapid uplift concentrated in the last 10 million years. Geologists divide the Andean Volcanic Belt into four segments, Northern, Central, Southern, and Austral, separated by stretches where the subducting slab flattens out and volcanism largely shuts off, a pattern most pronounced beneath central Chile and Argentina.