Summer Coon - Del Norte, CO
The Summer Coon volcanic complex is a highly eroded volcano near Del Norte, Colorado in the San Juan volcanic field. Below are two views, the first is a satellite view which shows just how eroded it is (it's easy to miss). The second is a trails view (less busy than a topo for this area), which reveals more classic volcanic features.
As the lower picture reveals, a central intrusive conduit resides in the center. Further, radial dikes surround and extend from the feature. The volcano is part of the Conejos Formation, which took place 31.1 to 34.7 mya. This is a mafic formation, with rhyolite, andestite and pyroclastic members.
There's an asymmetrical depression spanning north-northeast indicating a tilting of Summer Coon. Research suggests this happened after volcanic activity had stopped since original flows were probably symmetrical. Also, the dike patterns would have been more complex.
This has proved to be a valuable tool for dating the Rio Grande depression. Meaning the tilting must've taken place after the extinction of Summer Coon. The Rio Grande depression is an important event since it's responsible for much of the extreme volcanic activity in the area.
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