O'Leary Peak is an extinct

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

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 ...

volcano A volcano is commonly defined as a vent or fissure 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 oft ...

within 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 rangi ...

, north of

Flagstaff, Arizona Flagstaff ( ), known locally as Flag, is the county seat of Coconino County, Arizona, in the southwestern United States. As of the 2020 United States census, the city's population was 76,831. Flagstaff is the principal city of the Coconino Cou ...

, and to the northwest of Sunset Crater National Monument. A fire lookout tower was built on a subsidiary eastern peak. It has an elevation of .

Gallery

File:The Peaks from OLeary Lookout.jpg, View of the

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

from O'Leary Lookout, 2009 File:olearyandesite.jpg, Sample of

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

porphyry from summit of O'Leary peak

References

External links

*
"O'Leary Peak Trail"

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, with elevations ranging from 2,600 feet to the highest point in Arizona at 12,633 feet (H ...

. * {{Mountains of Arizona Volcanoes of Arizona Mountains of Arizona Landforms of Coconino County, Arizona Extinct volcanoes of the United States Mountains of Coconino County, Arizona Lava domes of the United States Pleistocene lava domes