The Algodones Sand Dunes of the Imperial Sand Dunes Recreational Area are the largest sand dunes in California. This dune system extends for more than 45 miles along the eastern edge of the Imperial Valley in a band averaging six miles in width in a northwest-southeast line that correlates to the prevailing northerly and westerly wind directions. The dune system is divided into many different areas. The wilderness area lies divided into two distinct zones: the primary dunes on the west side and the secondary dunes on the east. The former are taller and larger, and composed of noticeably coarse sand. The latter are smaller, made up of finer sands that are periodically shifted even farther east by prevailing winds.
Millions of years ago the earth's crust shifted along the San Andreas Fault, the coastal mountains were pushed up, cutting off the moisture-laden air coming from the ocean. At the same time, the interior plains of Southern California began to drop, forming a basin known as the Salton Sink or Graben; gradually, the region dried.
The area that the Colorado River flowed through in this region was so flat that the course of the river varied, being periodically diverted in one direction or another by flood deposits. At times the river flooded the Salton Sink forming a freshwater lake called Lake Cahuilla.
It’s believed that the dunes formed from windblown beach sands of Lake Cahuilla. The prevailing westerly and northwesterly winds carried the sand eastward from the old lakeshore to their present location. This process continues today. Prevailing winds cause the dunes to migrate southeast at the rate of approximately one foot per year. The primary force shaping the dunes is wind, and by understanding the relationship of wind to sand, you can learn to "read" the dunes. Dunes are generally oriented at right angles to the wind. Since the wind here generally blows west to east, the dune crests generally follow a north-south orientation.
"What a desolate place this is." - C-3PO
DID YOU KNOW?
The dunes were used to film parts of Road to Zanzibar, Stargate, Resident Evil: Extinction and the Tatooine scenes in the Star Wars series.
Types of Dunes Classification Triangle -Interactive
TO LOG THIS CACHE:
1) Classify the dunes you see from this location using the “Types of Dunes Classification Triangle”.
2) When was this area of the park your standing on dedicated?
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