The San Juan Mountains of Southwest Colorado (which give the San Juan Skyway its name) are special. The early Ute Indians believed they were the handiwork of gods. Whoever or whatever sculpted them used a special pallet. Geologists theorize that their formation began over 2 billion years ago during the Precambrian era when intense movement of the tectonic plates created stresses within the earth’s crust which slowly pushed the Rockies skyward. The Colorado Rockies are in fact, according to scientists, continuing to stretch towards the sun at the rate of about an inch a year. Subsequent to their initial formation, periods of calm and upheaval alternated in the area of the Rockies, grinding up and shifting the rocks and producing basins for inland seas. Sedimentary deposits formed which today provide some of the most beautiful red rock cliff vistas in the Animas and Delores River valleys.
Mancos shale, which provided the foundation for Mesa Verde, was also deposited on ancient sea bottoms, along with the aptly named cliffhouse sandstone. About 40 million years ago, great volcanoes erupted in the San Juan Range, adding to the awe-inspiring beauty of this Rocky Mountain range. Red Mountain, which gets its namesake color from oxidized minerals within the rock, was created from lava flows, as were the mountains surrounding Telluride.
To all of this geologic activity, we owe the richness of the mineral wealth of the San Juans. Cracks formed in the bedrock allowed mineral-laced solutions to percolate up from the earth’s hot center and harden into rich veins of ore. Calderas, collapsed volcanic cones, provide miners with exceptionally rich areas in which to find and exploit veins of gold, silver and other metals.
Explorer John Charles Fremont first saw the ragged silhouettes of the San Juan’s in 1848 and described them in a letter to his wife as “one of the highest, most rugged and impracticable of all the Rocky Mountain Ranges, inaccessible to the trappers and hunters even in the summer time.” What will you say when you drive through the rugged peaks, steep valleys, and wildflower-laden meadows of the San Juan Skyway?