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
Aconcagua The colorful greenish, blueish and grey deposits that can be seen in the Horcones Valley and south of Puente Del Inca, are carbonates, limestones, turbidites and evaporates that filled this basin. The red colored rocks are intrusions, cinder deposits and conglomerates of volcanic origin. In mountaineering terms, Aconcagua is technically an easy mountain if approached from the north, via the normal route. Aconcagua is arguably the highest "non-technical" mountain in the world, since the northern route does not absolutely require ropes, axes, and pins. Although the effects of altitude are severe (atmospheric pressure is 40% of sea-level at the summit),