The Phoenix Mountains are a

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have aris ...

located in central

Phoenix, Arizona Phoenix ( ) is the List of capitals in the United States, capital and List of cities and towns in Arizona#List of cities and towns, most populous city of the U.S. state of Arizona. With over 1.6 million residents at the 2020 census, it is the ...

. With the exception of Mummy Mountain, they are part of the Phoenix Mountain Preserve. They serve as a municipal park and offer

hiking A hike is a long, vigorous walk, usually on trails or footpaths in the countryside. Walking for pleasure developed in Europe during the eighteenth century. Long hikes as part of a religious pilgrimage have existed for a much longer time. "Hi ...

mountain biking Mountain biking (MTB) is a sport of riding bicycles off-road, often over rough terrain, usually using specially designed mountain bikes. Mountain bikes share similarities with other bikes but incorporate features designed to enhance durability ...

and

equestrian The word equestrian is a reference to equestrianism, or horseback riding, derived from Latin ' and ', "horse". Horseback riding (or riding in British English) Examples of this are: *Equestrian sports *Equestrian order, one of the upper classes in ...

trails at a variety of different access points.

Peaks

The major peaks of the Phoenix Mountain complex are: * Moon Mountain * Lookout Mountain * Shadow Mountain * Shaw Butte * North Mountain * Echo Mountain * Stoney Mountain * South Mountain *

Piestewa Peak Piestewa Peak ( ; , formerly Squaw Peak), at is the second highest point in the Phoenix Mountains, after Camelback Mountain, and the third highest in the city of Phoenix, Arizona. It is located in the Piestewa Peak Recreation Area within the ...

(formerly named ''Squaw Peak'') * Mummy Mountain *

Camelback Mountain Camelback Mountain () is a mountain in Phoenix, Arizona, United States. The English name is derived from its shape, which resembles the hump and head of a kneeling camel. The mountain, a prominent landmark of the Phoenix metropolitan area, is l ...

Sunnyslope Mountain Sunnyslope Mountain also known as "S" Mountain''The Arizona Republic'', November 2, 2001 is a large, rocky, nearly symmetric hill in the Sunnyslope section of Phoenix, Arizona. It is located near Central Avenue and Hatcher Road. The southern slop ...

Geology

The nearly 1.7 billion year (1.7 Gya) history of the formation of the Phoenix Mountains is defined by distinctive episodes intensive submarine volcanism and

orogeny Orogeny () is a mountain-mountain formation, building process that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An or develops as the compressed plate crumples and is tectonic uplift, u ...

in the

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

, erosion in the Mesozoic, and lastly, Basin and Range development. Generally speaking, the entire Phoenix Mountain structure is an exposed remnant of northeast-striking Proterozoic low-grade metamorphic rock that is thought to be nearly 12-km thick. The first deposits from 1.7 Gya were in an oceanic volcanic arc setting which gradually changed to sub-aerial volcanic and near-shore deposits. This large section of crust was subjected to long scale crustal shortening during the

Mazatzal orogeny The Mazatzal orogeny was an orogenic event in what is now the Southwestern United States from 1650 to 1600 Mya in the Statherian Period of the Paleoproterozoic. Preserved in the rocks of New Mexico and Arizona, it is interpreted as the coll ...

which formed isoclinal folds and shear zones. North Mountain and Shaw Butte, which are composed of fine to medium grained greenstone and intruded

granodiorite Granodiorite ( ) is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from gra ...

respectively, are the oldest mountain exposures in the area. Moving southeast the mountains become increasingly younger in geologic age. Stoney Mountain is also composed of similar greenstone. The

Arizona State Route 51 Arizona State Route 51 (SR 51), also known as the Piestewa Freeway, is a numbered state highway in Phoenix, Arizona. It connects Interstate 10 in Arizona, Interstate 10 and Arizona State Route 202, Loop 202 just outside downtown Phoenix w ...

, near Dreamy Draw, exposes rock that has distinctly slaty cleavage or schistosity which is characteristic of gray metasedimentary

phyllite Phyllite ( ) is a type of foliation (geology), foliated metamorphic rock formed from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. I ...

is part of a larger synclinal fold of conglomeratic and cross-bedded

quartzite Quartzite is a hard, non- foliated metamorphic rock that was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tecton ...

and volcaniclastic rocks that extend toward Quartzite Ridge. No geologic record is retained in the Phoenix area regarding what happened between the Proterozoic until the Late Tertiary sedimentary deposits that exist such as the upper portion of Camelback Mountain (which is an

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

aged red sandstone). This contact is known as an angular unconformity. The mountains of Lookout Mountain and the Moon Hill areas are formed from thick sequences of basaltic lava and conglomerate. This period of wide-scale volcanism and tectonic activity evidences how active Basin and Range development was roughly 20 million years ago. The Basin and Range extension which pulled the crust in the ancient Phoenix area helped to form the parallel mountain ranges seen throughout the Southwest.

Other features

The mountains contain the Phoenix Mountain Preserve, which includes the Dreamy Draw Recreation Area, Lookout Mountain Preserve, North Mountain Preserve and Piestewa Mountain Park. The Dreamy Draw Recreation Area is located in the pass between the Stoney/Echo mountain ridge and Piestewa Peak known as ''Dreamy Draw''. The name originated from the neurological effects suffered by miners who worked the area's

cinnabar Cinnabar (; ), or cinnabarite (), also known as ''mercurblende'' is the bright scarlet to brick-red form of Mercury sulfide, mercury(II) sulfide (HgS). It is the most common source ore for refining mercury (element), elemental mercury and is t ...

(mercury sulfide) mine.Richard Nilsen
"Lore of Dreamy Draw: Mad Men, Green Men and Lots of Great Hikes"
''Arizona Republic'', December 19, 2008 There is a flood prevention dam in the ''Dreamy Draw'' area.

Trails

Charles M. Christiansen Memorial Trail

The trail was dedicated in 1986 to Charles Milo Christiansen, the former director of Phoenix Parks and Recreation who led efforts to preserve the Phoenix Mountains. There is a memorial plaque at the western trailhead at Mountain View Park. The trail is long and has a total elevation gain of 200', though the elevations at both trailheads are the same. It connects North Mountain Park with Stony Mountain and Piestewa Peak Park.John Stanley

''Arizona Republic'', June 13, 2006

References

External links

{{authority control Geography of Phoenix, Arizona Mountain ranges of Arizona Mountain ranges of Maricopa County, Arizona Mountain ranges of the Sonoran Desert