There used to be an earthcache here but it was archived not too long ago. This spot deserves an EC though as this formation is a must see while traveling along Highway 50
I have passed by here a few times on my way to Montrose or Ouray and stopped and grabbed the original in 2023.
The Coords take you to a pull-out on Highway 50 in Curecanti National Recreation Area. Fully Handicapped accessible. No fees associated with this site.
Across the Blue Mesa Reservoir, you will see the Dillon Pinnacles, which will be the focal point of this Earthcache
During the Cenozoic era, approximately 26 to 35 million years ago, the area that is now Western Colorado was subjected to extensive volcanic activity. None of the volcanoes that existed then are present today, but evidence of there existence is all around. When a volcano erupts to the extent that it empties its chamber and collapses, it forms what is called a “caldera”.
Southwest of the Dillon Pinnacles, the remains of a caldera which was uplifted by the Gunnison Uplift can be observed. The caldera now forms the peaks of the rugged San Juan Mountains, such as Uncompahgre Peak – the sixth highest peak in Colorado.
Volcanic activity in the West Elk Mountains, to the north of Dillon Pinnacles, covered this area with volcanic ash and lava. This lava, along with mud flows, ash, and rock fragments, formed a sedimentary rock called “breccia”.
The West Elk Breccia settled at a depth of over 1,000 feet thick over the harder igneous and metamorphic rock of the Dillon Pinnacles. The breccia is composed of hardened molten rock (magma) “clasts” and an ashy material called “matrix”, formed by the mud flows and ash, that cement the clasts together.
The volcanic activity of the San Juans to the south later covered this area with incandescent ash which retained sufficient heat to fuse together and form a hard “cap rock” over the tops of the mesas in this area. The harder igneous rock clasts and “cap rock” are more resistant to erosion than the ashy matrix of the breccia.
The pinnacles you see were made as a result of what is called flow deposits. The deposits as well as thousands of years of natural elements is what gives the pinacles their unique shapes.
Logging requirements:
To log your visit to this location, message me the answers to the following questions. Logs without submitted answers will be deleted
1. What three elements of nature are responsible for carving away the landscape, creating the pinnacles?
2. Do you see any examples of the harder "cap rock" on the mesa? If so, what do you see?
3. Include a photo of you or your group with the pinnacles in the background
This was placed by a proud
