A geological layer cake
The Aktau Mountains are a 30-kilometer-long range of sedimentary badlands located in Kazakhstan's Altyn-Emel National Park. Their name translates to "White Mountains," but the landscape is famous for its bright stripes of red, yellow, green, and blue. These colors are not random; they are a record of changing environmental conditions during the Paleogene and Neogene periods, roughly 25 to 30 million years ago. At that time, this arid desert was the floor of a large freshwater lake system.
The distinct colors come from different minerals within the clay and sandstone layers. The bright red and pink strata were formed in a hot, humid climate when iron-rich sediments were exposed to atmospheric oxygen, creating hematite. The white, yellow, and greenish layers indicate periods when the lake bed was submerged in an oxygen-poor, or reducing, environment. The entire sedimentary deposit reaches a thickness of up to 1,200 meters, a massive vertical record of climate history. The soft rock erodes easily, and seasonal rains constantly carve new channels and expose different strata, changing the appearance of the canyons from year to year.