At the Crestone Brewery!
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7 months 5 days ago
Crestone is off to the left!
View of Great Sand Dunes from International Space Station
#ScienceSaturday - Many visitors wonder: Why is there so much sand only here, but not at other locations along the mountains?
In this view from space, part of the answer becomes clear. The Sangre de Cristo Mountains are curved here, and at the same location are low passes to funnel wind and sand from the valley floor into this pocket.
Then why doesn't sand accumulate, for instance, at the base of La Veta Pass to the south? The mountains also curve there below a low pass.. The answer is that this northeast part of the San Luis Valley is a closed basin. Streams carrying sand into this basin don't exit, so all the sand they carry is deposited here. In the past, these streams fed into huge lakes; when these lakes disappeared through natural climate change, vast quantities of sand blew and accumulated here below Mosca, Medano, and Music Passes. In other parts of the valley, and in most places in the Rocky Mountains, sands are continually washed away and carried downstream into larger and larger rivers.
There are some other locations in the Rocky Mountains where sand accumulates in a basin, then blows into a pocket of the mountains. In North Park, Colorado, near the town of Walden, are two dunefields tucked into mountain pockets. Throughout the western U.S., many dunefields are formed the same way. But the San Luis Valley is the size of the state of Connecticut, with huge quantities of sand, a low curve in the mountains, and streams to recycle the sand into the tallest dunes in North America!
Visit the park's geology pages for more:
#greatsanddunes #geology #NASA #InternationalSpaceStation #sand
8 months 2 weeks ago