Mount Elden or Elden Mountain (

Hopi The Hopi are a Native American ethnic group who primarily live on the Hopi Reservation in northeastern Arizona, United States. As of the 2010 census, there are 19,338 Hopi in the country. The Hopi Tribe is a sovereign nation within the Unite ...

: Hovi'itstuyqa) is located in central

Coconino County Coconino County is a county in the north-central part of the U.S. state of Arizona. Its population was 145,101 at the 2020 census. The county seat is Flagstaff. The county takes its name from ''Cohonino'', a name applied to the Havasupai p ...

northeast of Flagstaff,

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

. It takes its name from one of the region's earliest

Anglo Anglo is a prefix indicating a relation to, or descent from, the Angles, England, English culture, the English people or the English language, such as in the term '' Anglosphere''. It is often used alone, somewhat loosely, to refer to people ...

settlers, John Elden, who, along with his family, established a homestead on the mountain's lower slopes and grazed sheep on the open grasslands below during the late 19th century. The mountain's exposed, rocky slopes are a dominant feature from almost any part of the city of Flagstaff, rising steeply nearly to an elevation of . Much of the vegetation on the southern and southeastern slopes of the mountain was destroyed by the human-caused Radio Fire in 1977 which burned . Despite its rugged appearance, steep

relief Relief is a sculptural method in which the sculpted pieces are bonded to a solid background of the same material. The term ''relief'' is from the Latin verb ''relevo'', to raise. To create a sculpture in relief is to give the impression that the ...

, and nearly of surface area, Mount Elden is easily accessible via an extensive, well-developed road and non-motorized

trail A trail, also known as a path or track, is an unpaved lane or small road usually passing through a natural area. In the United Kingdom and the Republic of Ireland, a path or footpath is the preferred term for a pedestrian or hiking trail. Th ...

system that is part of the

Coconino National Forest The Coconino National Forest is a 1.856-million acre (751,000 ha) United States National Forest located in northern Arizona in the vicinity of Flagstaff. Originally established in 1898 as the "San Francisco Mountains National Forest Reserve", th ...

Geology

Mount Elden is one of five large peripheral

silicic Silicic is an adjective to describe magma or igneous rock rich in silica. The amount of silica that constitutes a silicic rock is usually defined as at least 63 percent. Granite and rhyolite are the most common silicic rocks. Silicic is the group ...

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

features within the greater

San Francisco Peaks The San Francisco Peaks (Navajo: , es, Sierra de San Francisco, Hopi: ''Nuva'tukya'ovi'', Western Apache: ''Dził Tso'', Keres: ''Tsii Bina'', Southern Paiute: ''Nuvaxatuh'', Havasupai-Hualapai: ''Hvehasahpatch''/''Huassapatch''/''Wik'hanbaja'', ...

volcanic system (part of the

San Francisco volcanic field The San Francisco volcanic field is an area of volcanoes in northern Arizona, north of Flagstaff, US. The field covers 1,800 square miles (4,700 km²) of the southern boundary of the Colorado Plateau. The field contains 600 volcanoes rang ...

) which include the nearby

Dry Lake Hills Dry or dryness most often refers to: * Lack of rainfall, which may refer to **Arid regions **Drought * Dry or dry area, relating to legal prohibition of selling, serving, or imbibing alcoholic beverages * Dry humor, deadpan * Dryness (medical) * ...

, the Hochderffer and White Horse Hills to the northwest, and

O'Leary Peak O'Leary Peak is an extinct Pleistocene lava dome volcano within the San Francisco volcanic field, north of Flagstaff, Arizona, and to the northwest of Sunset Crater National Monument. A fire lookout tower was built on a subsidiary eastern peak. ...

to the northeast. Because these features developed within close proximity of the San Francisco Mountain

strato-volcano A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and pe ...

there is a strong likelihood that each is a geologic subsidiary of the larger mountain. Geologically, Mount Elden is a

lava dome In volcanology, a lava dome is a circular mound-shaped protrusion resulting from the slow extrusion of viscous lava from a volcano. Dome-building eruptions are common, particularly in convergent plate boundary settings. Around 6% of eruptions on ...

composed almost entirely of

dacitic Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite ...

lava flows which emerged from several vents. These features emerged as intrusive emplacements within sedimentary blocks or as

viscous The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the inter ...

extrusive Extrusive rock refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. In contras ...

flows in which the younger flows partially covered the older, lower flows. Geologic evidence suggests that the eruption of the mountain, which occurred at linear vents along regional faults, was a non-explosive event that took place during several

flow sequence Flow may refer to: Science and technology * Fluid flow, the motion of a gas or liquid * Flow (geomorphology), a type of mass wasting or slope movement in geomorphology * Flow (mathematics), a group action of the real numbers on a set * Flow (psych ...

s. Likewise, because of the high viscosity of the dacite, it is likely that the mountain formed in the short period of a few months' time. The mountain's overlapping flows commonly take lobe-like shapes which display a variety of flow characteristics and features including concentric benches,

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...

s, ramping shear

fractures Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...

, longitudinal tension fractures, and conjugate shear fractures. Positioned within the central part of Mount Elden, on the mountain's eastern and northwestern flanks, are two

sedimentary Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...

blocks. Both of these blocks display characteristics of

uplift Uplift may refer to: Science * Geologic uplift, a geological process ** Tectonic uplift, a geological process * Stellar uplift, the theoretical prospect of moving a stellar mass * Uplift mountains * Llano Uplift * Nemaha Uplift Business * Uplif ...

that most likely occurred as dacitic

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

intruded into the sedimentary

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

at a shallow depth and uplifted the layers, causing them to dip away from the mountain. These blocks of sedimentary material are unique to the mountain, which otherwise is uniformly composed of silicic dacite.

Geology

See also