<Tr> <Td> This box: <Ul> <Li> view </Li> <Li> talk </Li> <Li> edit </Li> </Ul> </Td> </Tr> <Ul> <Li> view </Li> <Li> talk </Li> <Li> edit </Li> </Ul> <P> The Andes are a Mesozoic--Tertiary orogenic belt of mountains along the Pacific Ring of Fire, a zone of volcanic activity that encompasses the Pacific rim of the Americas as well as the Asia - Pacific region . The Andes are the result of plate tectonics processes, caused by the subduction of oceanic crust beneath the South American Plate . The main cause of the rise of the Andes is the compression of the western rim of the South American Plate due to the subduction of the Nazca Plate and the Antarctic Plate . To the east, the Andes range is bounded by several sedimentary basins, such as Orinoco, Amazon Basin, Madre de Dios and Gran Chaco, that separate the Andes from the ancient cratons in eastern South America . In the south, the Andes share a long boundary with the former Patagonia Terrane . To the west, the Andes end at the Pacific Ocean, although the Peru - Chile trench can be considered their ultimate western limit . From a geographical approach, the Andes are considered to have their western boundaries marked by the appearance of coastal lowlands and a less rugged topography . The Andes Mountains also contain large quantities of iron ore located in many mountains within the range . </P> <P> The Andean orogen has a series of bends or oroclines . The Bolivian Orocline is a seaward concave bending in the coast of South America and the Andes Mountains at about 18 ° S. At this point the orientation of the Andes turns from Northwest in Peru to South in Chile and Argentina . The Andean segment north and south of the orocline have been rotated 15 ° to 20 ° counter clockwise and clockwise respectively . The Bolivian Orocline area overlaps with the area of maximum width of the Altiplano Plateau and according to Isacks (1988) the orocline is related to crustal shortening . The specific point at 18 ° S where the coastline bends is known as the "Arica Elbow". Further south lies the Maipo Orocline or Maipo Transition Zone located between 30 ° S and 38 ° S with a break in trend at 33 ° S. Near the southern tip of the Andes lies the Patagonian orocline . </P>

Which geographic feature lies east of the andes mountains