Natural regions of Chile for reference purposes. These natural regions are ordered from north to south and reduced to five natural regions: Each has its own characteristic vegetation, fauna, climate, and, despite the omnipresence of both the Andes and the Pacific, its own distinct topography. Most of the region is covered by the Atacama Desert and has a dry arid climate. The coast range has peaks over 2000 m and ends in cliffs in the coast. There are large salt flats in the Intermediate depression and the Andes. Norte Grande has Chile's highest mountains including Ojos del Salado (6,891 m) but host also the
Ojos del Salado of the Nazca Plate beneath the South America Plate became increasingly shallower and this caused volcanism to shift from the Maricunga Belt to the Ojos del Salado region. The Paleozoic basement crops out only northwest of Nevado Tres Cruces. Other geologic units in the region are Oligocene sedimentary units and volcanic rocks ranging from Oligocene age to less than 1.5 million years old. The area is part of a tectonic boundary between a volcanically active region north of the boundary and a less volcanically active region south of the boundary, which is also characterized by geographical differences, e.g. the presence