Earth’s widest high plain outside Tibet sits in the Andes
The Altiplano—Quechua and Aymara Qullaw—is west-central South America’s high plain, the most extensive plateau on Earth after Tibet. Averaging about 3,750 metres, it holds Lake Titicaca, glaring salt flats, mining towns, and ruins left by the Chiripa, Tiwanaku, and Inca, all under thin, cold air.
Bolivian highland cities such as El Alto beside Oruro, and Peruvian centres Juliaca with lakeside Puno, punctuate the plain. The northeast is wetter; the arid southwest hosts salares. Unlike Tibet’s drainage, this Andean table is endorheic, spanning northern Chile, western Bolivia, southern Peru, and northwest Argentina.
Pre-Columbian cultures thrived here before sixteenth-century Spanish conquest. Today mining, llama and vicuña herding, urban services, and growing tourism pay the bills on a landscape that still feels closer to the sky than to the sea.
An average height of about 3,750 metres leaves the air thin and hypoxic for the Qulla, Uros, Quechua and Aymara communities who live there. Unlike Tibet, the plateau is dominated on its west by huge active volcanoes of the Central Volcanic Zone, among them Parinacota at 6,348 metres. Geologists offer several explanations for how such flat ground came to sit so high: older weaknesses in the crust, magma rising from the asthenosphere, climate steering erosion, and the loss of dense lower lithosphere that let the region float upward.
During the Pleistocene, vast lakes flooded both ends of the plain. Titicaca, South America's largest lake, on the Bolivia–Peru border, is a survivor; the salt flats of Uyuni and Coipasa are what remained when others evaporated. Lake Poopó had vanished completely by December 2015. Rain ranges from under 200 millimetres a year in the southwest to over 800 near Titicaca, arriving mostly between December and March, and the lake's great thermal mass softens the sharp swings between day and night nearby.
Source: Altiplano
