Tuesday, January 22, 2008

The Atacama Desert - World's Driest

After flying half way up the length of the South American continent, we landed in Calama in northern Chile. Chile is the Earth's longest country and if it were transposed latitutinally to the north, it would stretch from Ketchikan, Alaska to Acupulco, Mexico! It goes from glaciated mountains in Patagonia, to the temperate wine growing region near Santiago, to the Atacama Desert, which is the Earth's driest. Some places here do not receive rain for decades!

These are the Andes Mountains as we approach Calama in our jet.

Look at this - 8,000 feet above sea level and not a hint of vegetation anywhere. 8,000 feet and nothing but gravel!

A fantastic angular unconformity. The rocks below were once flat-lying sediments. They were tilted to vertical during the uplift of the Andes. Then they were eroded flat before the upper layers buried them. Scenes like this inspired original geologic thinking in humans.

2020 Update - The lower brown and upturned beds belong to the San Pedro Formation, shale, sandstone, conglomerate, gypsum and salt deposited in a playa environment. It is Late Oligocene to Miocene in age. It is overlain by the Vilama Formation of likely Pliocene age. It is composed of silt, sand, and gravel deposited by streams out of the Andes Mountains.

Submitted by fellow geologist Paul "Geoman" in Texas

Atacama ghosts posing as pillars of salt. This is part of the Salt Range.

I visited the world's highest geyser basin on Tuesday. This is at 13,000 feet and the geysers were spectacular!

This is a boiling mud pot, reminiscent of Yellowstone. There are at least 50 to 60 geysers constantly erupting in this field.

Awesome thermal structures in El Taito geyser field. It started out cloudy but then the sun made its way through the mist.

The high Andes in the background of the geyser field rise to over 19,000 feet. The snow is unexpected however considering it is summer down here.

Just another awesome Andean volcano with summer time snow. This one is called Sarécabur and at 19,500 feet, it forms the international bounday with Bolivia. The Andes and the Atacama have received a lot precipitation recently.

Vicuña's are related to llama's and I saw dozens of them running across the altiplano as we drove home from the geyser field.

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