Tushar Mountains - Geology and Landforms

Geology and Landforms

The spectacular peaks of the Tushars were formed between 22 and 32 million years ago by volcanic activity that included a calamitous explosion that blew off the top of a massive peak. At the cusp of the Great Basin, the range also shares characteristics of the Colorado Plateau Province to the east. Geologist and explorer Clarence Dutton called the high peaks of the Tushars: "noble cones ending in sharp cusps stand pre-eminent, while behind them numerous dome-like masses rise to nearly the same altitude. The resultant sculptural forms are correspondingly bold and craggy."

Geologically complex, this area dominated by past volcanism, is composed of lava flows, ash flow tuffs from calderas, volcanic domes, cinder cones, rhyolite, basalt-like rocks, conglomerate, and metals such as gold, molybdenum and uranium. The area contains developed and undeveloped geothermal activity, fluorite, and the hydrothermally-altered rocks of Big Rock Candy Mountain.

In a survey of Natural Landmark Areas of the North Portion of the Colorado Plateau, Biotic and Geologic Themes, conducted by Brigham Young University scientists, the Big Rock Candy Mountain Altered Zone was described as "unexcelled in the Colorado Plateau." The same study recognized a grouping of volcanic rocks known as the Skinner Canyon Ignimbrite, calling the exposure of low-grade volcanic glass in Clear Creek Canyon "one of the most spectacular displays of strongly jointed ignimbrites in the Colorado Plateau."