The Atacama Desert may be the oldest desert on earth, and has experienced extreme hyperaridity for at least 3 million years, making it the oldest continuously arid region on earth. The long history of aridity raises the possibility that supergene mineralisation, under the appropriate conditions, can form in arid environments, instead of requiring humid conditions.
Geological research suggests that in some sections of the Atacama Desert, such as in today’s Chile, hyperaridity has persisted for the last 200 million years (since the Triassic)..Some parts of Atacama Desert, especially, surroundings of the abandoned Yungay town in Antofagasta Region, Chile are arguably the driest places on Earth,and are virtually sterile because they are blocked from moisture on both sides by the Andes mountains and by the Chilean Coast Range. A coastal inversion layer created by the cold Humboldt Current and the anticyclone of the Pacific is essential to keeping the climate of the Atacama dry.
If you visit Peru, you will likely hear someone say: “It never rains in Lima”—the nation’s capital. Shivering in the chilly, damp air, you may well wonder if that is so.
LIMA is located in the great desert that runs along the Pacific Coast of South America—a region having one of the world’s most unusual climates. This arid strip of land stretches from the Sechura Desert in Peru’s far north all the way to the Atacama Desert of northern Chile.
The coastal desert lies between the rugged Andes and the azure Pacific Ocean. From a distance, there appears to be nothing along the coast but stark, rugged hills of stone and sand in every imaginable shade of beige and brown. Erosion has draped many of the hillsides with cascades of brown rocks. These gradually make their way down the slope toward the sea, occasionally nudged along by the frequent earth tremors that occur here.
Once the rocks reach the shore, the pounding waves of the Pacific slowly grind them into sand, which the wind forms into crescent-shaped dunes. In parts of this vast desert, no rain has been recorded in 20 years, making it one of the driest spots on earth.