La Sal Mountains

The La Sal Mountains or La Sal Range is a mountain range located in Grand and San Juan counties in the U.S. state of Utah, along the border with Colorado. The range rises above and southeast of Moab and north of the town of La Sal. This range is part of the Manti-La Sal National Forest and the southern Rocky Mountains. The maximum elevation is at Mount Peale, reaching 12,721 feet (3,877 m) above sea level.

La Sal Mountains
La Sal Mountains as seen from Arches National Park
Highest point
PeakMount Peale
Elevation12,721 ft (3,877 m)
Coordinates38°26′19″N 109°13′45″W
Geography
La Sal Mountains is located in Utah
La Sal Mountains
Location of the La Sal Range within Utah
CountryUnited States
StateUtah
Range coordinates38°26′56″N 109°14′28″W
Parent rangeRocky Mountains

The range contains three clusters of peaks separated by passes. The peaks span a distance of about 10 miles (16 km). The name of the range dates to Spanish times, when the Sierra La Sal (meaning the "Salt Mountains") was a prominent landmark on the Old Spanish Trail between Santa Fe and Los Angeles.

Geology
Mountain ranges associated with laccoliths and other igneous intrusions on part of the Colorado Plateau. The red dot marks the Four Corners, the intersection of Utah, Colorado, New Mexico, and Arizona. L, La Sal Mountains; A, Abajo Mountains; S, (Sleeping) Ute Mountain; C, Carrizo Mountains; N, Navajo Mountain; H, Henry Mountains.

The range formed due to intrusion of igneous rocks and subsequent erosion of the surrounding less-resistant sedimentary rocks. The most abundant igneous rocks are porphyritic, with phenocrysts of hornblende and plagioclase: these rocks are called diorite in some accounts, but trachyte in at least one other source. Syenite, some containing the unusual mineral nosean, makes up a few percent of the igneous rocks present. Some igneous intrusions have the shapes of laccoliths. The ages of these igneous rocks fall between 25 and 28 million years. The magmas were emplaced into sedimentary rocks with ages from Permian to Cretaceous.

The La Sal Mountains rise high over the surrounding Colorado Plateau. Two other ranges on the Plateau, the Abajo Mountains and the Henry Mountains, formed around igneous intrusions of about the same age. Yet other nearby ranges, such as the Carrizo Mountains and Ute Mountain, formed about otherwise similar intrusions emplaced about 70 million years ago. The formation of these igneous rocks in two distinct time intervals has attracted the interest of scientists seeking explanations for magma production below relatively stable parts of the Earth's crust.

The La Sals at Sunset from Gemini Bridges Road

Peaks of the La Sal Mountains
Little Tuk (left) and Mt. Tukuhnikivatz (right) of the La Sal Range in summer, seen from the south.
Winter view of Horse Mountain, looking east on the La Sal loop road, at Pinhook Valley, Utah
The significant peaks of the La Sal Mountains are:
peak name feet/meter
Mount Peale 12,721 feet (3,877 m)
Mount Mellenthin 12,645 feet (3,854 m)
Mount Tukuhnikivatz 12,482 feet (3,805 m)
Mount Waas 12,331 feet (3,758 m)
Manns Peak 12,272 feet (3,741 m)
Mount Laurel 12,271 feet (3,740 m)
Mount Tomasaki 12,239 feet (3,730 m)
Pilot Mountain 12,200 feet (3,719 m)
Green Mountain 12,163 feet (3,707 m)
Little Tuk 12,048 feet (3,672 m)
Castle Peak 12,044 feet (3,671 m)
La Sal Peak 12,001 feet (3,658 m)

See also

References

Jules D. Friedman and A. Curtis Huffman Jr., Coordinators, Laccolith Complexes of Southeastern Utah: Time of Emplacement and Tectonic Setting—Workshop Proceedings, United States Geological Survey Bulletin 2158, 292 pages, 1998. http://pubs.usgs.gov/bul/b2158/B2158.pdf

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