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
Tibesti Mountains highest peak in the Tibesti Mountains, as well as the highest point in Chad and the Sahara Desert, is the Emi Koussi, located at the southern end of the range. Other prominent peaks include Pic Toussidé at and the Ehi Timi on its western side, the Tarso Yega, the Tarso Tieroko, the Ehi Mousgou, the Tarso Voon, the Ehi Sunni, and the Ehi Yéy near the center of the range. The Mouskorbe and the Kegueur Terbi are two peaks notable for their height in the northeastern part of the mountain range. The Bikku Bitti, the highest point in Libya, is