Rhyolite is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite.
The Chiricahua Mountains massif is a large mountain range in southeastern Arizona which is part of the Basin and Range province of the west and southwestern United States and northwest Mexico; the range is part of the Coronado National Forest. The highest point, Chiricahua Peak, rises 9,759 feet (2,975 m) above sea level, approximately 6,000 feet (1,800 m) above the surrounding valleys. The range takes its name from the Chiricahua Apaches native to the region.
The Sierra Blanca is an ultra-prominent range of volcanic mountains in Lincoln and Otero counties in the south-central part of the U.S. state of New Mexico. The range is about 40 miles (64 km) from north to south and 20 miles (32 km) wide.
The Carmel Formation is a geologic formation in the San Rafael Group that is spread across the U.S. states of Wyoming, Utah, Colorado, north east Arizona and New Mexico. Part of the Colorado Plateau, this formation was laid down in the Middle Jurassic during the late Bajocian, through the Bathonian and into the early Callovian stages.
Notch Peak is a distinctive summit located on Sawtooth Mountain in the House Range, west of Delta, Utah, United States. The peak and the surrounding area are part of the Notch Peak Wilderness Study Area (WSA). Bristlecone pines, estimated to be 3,000 to 4,000 years old, are located on the ridges surrounding Notch Peak.
The West Elk Mountains are a high mountain range in the west-central part of the U.S. state of Colorado. They lie primarily within the Gunnison National Forest, and part of the range is protected as the West Elk Wilderness. The range is primarily located in Gunnison County, with small parts in eastern Delta and Montrose counties.
The Mount Pleasant Caldera is a large eroded Late Devonian volcanic caldera complex, located in the northern Appalachian Mountains of southwestern New Brunswick, Canada. It is one of few noticeable pre-Cenozoic calderas, and its formation is associated to a period of crustal thinning that followed the Acadian orogeny in the northern Appalachian Mountains. It sits relatively near to the coastline.
The Tushar Mountains are the third-highest mountain range in Utah after the Uinta Mountains and the La Sal Range. Located in the Fishlake National Forest, Delano Peak, 12,174 ft NAVD 88, is the highest point in both Beaver and Piute counties and has a prominence of 4,689 ft. Delano Peak is named for Columbus Delano (1809–1896), Secretary of the Interior, during the Grant administration. The Tushars receive an ample amount of snow annually even though they are situated within the rainshadow of the Sierra Nevada range in California and the Snake Range located in Nevada.
The Delamar Mountains are a mountain range in Lincoln County, Nevada, named after Captain Joseph Raphael De Lamar. The range extends for approximately 50 miles (80 km) in a NNE–SSW orientation with a width of about 11 miles (18 km). Surrounding ranges include the Burnt Springs Range and the Chief Range to the north, the Clover Mountains and Meadow Valley Mountains to the east and the Sheep Range and South Pahroc Range on the west. The Delamar Valley lies to the west, the Kane Springs Valley to the east and the Coyote Springs Valley lies to the south of the range.
Tule Valley is a valley in Millard County, Utah, United States.
The Mountain Home Range is a north-south trending mountain range in western Beaver County in southwest Utah, United States. It is part of the Basin and Range Province. It is bound by Hamlin Valley to the west, Snake Valley to the north, Pine Valley to the east, and trends into the Indian Peak Range to the south. Collectively, the Mountain Home Range and Indian Peak Range are known as the Needle Mountains due to their jagged nature.
The Burbank Hills are a small northwest-southeast mountain range in western Utah, United States that lie entirely within the Hamlin-Snake Watershed, between the Snake Range and the Ferguson Desert. It is bounded by Snake Valley to the north, west, and south; and trends into the Tunnel Springs Mountains, to the southeast, opposite the Antelope Valley on its southeast border. It was named after the settlement of Burbank, Utah, and Margie Burbank Clay, the wife of local Judge E. W. Clay in the 1870s.
Mahogany Mountain is an ancient caldera volcano on the border of Oregon and Idaho, in Malheur County and Owyhee County, respectively. While its early history is largely unknown, its last eruption was probably 15.5 million years ago. This eruption ejected layers of rhyolite and produced tuff, creating formations of rock in the Leslie Gulch.
The Cricket Mountains are a 35-mile (56 km) long mountain range located in central-south Millard County, Utah, United States, on the east border of Sevier Lake, in the Great Basin Desert.
Topaz Mountain is a summit in the Thomas Range of Utah, east of the Thomas caldera. The summit and surrounding area are known for their abundances of semiprecious minerals including topaz, red beryl and opal.
Tomichi Dome rises north of U.S. Highway 50 west of Hot Springs Creek and south of Waunita Hot Springs Reservoir in the southeast quarter of Gunnison County, Colorado. It is situated within the Gunnison National Forest.
The Crystal Peak Dolomite is a geologic formation in the Wah Wah Mountains of western Utah. It preserves fossils dating to the Middle Ordovician period.
The geology of Utah, in the western United States, includes rocks formed at the edge of the proto-North American continent during the Precambrian. A shallow marine sedimentary environment covered the region for much of the Paleozoic and Mesozoic, followed by dryland conditions, volcanism, and the formation of the basin and range terrain in the Cenozoic.
