Geology of Chile the Taitao Peninsula, the Peru–Chile Trench subduction zone is the boundary between the South American and Nazca Plates. At Taitao, the Chile Triple Junction and the Nazca Plate subduct the South American Plate. In Norte Grande the mountains form a series of plateaus, such as Puna de Atacama and the Altiplano. At a south latitude of 27 degrees, Chile's highest mountain (Ojos del Salado) reaches a height of . Below 42 degrees south, the Andes split into a fjord landscape and the highest mountain is Monte San Lorenzo at . As the mountains ebb, the snow line lowers; in the
Volcanic Seven Summits Although Aconcagua, the highest peak in South America and the highest peak in the western hemisphere, does have a volcanic origin, its current high point is due to geological processes rather than being strictly volcanic. Due to this, Aconcagua is not considered to be a volcano on its own, at least not as a member of Volcanic Seven Summits. Topographic maps of the Argentina and Chile border region which contains the highest peaks suffer from poor accuracy, with elevation errors exceeding in many cases. However, the current consensus based on the most recent measurements places Ojos del Salado as the