Coconino Sandstone is a geologic

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

named after its exposure in

Coconino County, Arizona 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 ...

. This formation spreads across the Colorado Plateau province of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, including northern

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 ...

, northwest

Colorado Colorado (, other variants) is a state in the Mountain states, Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the wes ...

Nevada Nevada ( ; ) is a state in the Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. Nevada is the 7th-most extensive, ...

, and

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

This rock formation is particularly prominent in the Grand Canyon, where it is visible as a prominent white cliff-forming layer. The thickness of the formation varies due to regional structural features; in the Grand Canyon area it is only thick in the west, thickens to over in the middle and then thins to in the east. Either the

Kaibab Limestone The Kaibab Limestone is a resistant cliff-former, cliff-forming, Permian geologic formation that crops out across the U.S. states of northern Arizona, southern Utah, east central Nevada and southeast California. It is also known as the Kaibab Fo ...

Toroweap Formation The Middle Permian Toroweap Formation is a thin, darker geologic unit, between the brighter colored units of the Kaibab Limestone above, and Coconino Sandstone below. It is a prominent unit in Grand Canyon, Arizona, USA, found through section ...

overlies the Coconino Sandstone. The Coconino Sandstone is typically buff to white in color. It consists primarily of fine well-sorted quartz grains, with minor amounts of potassium feldspar grains deposited by

eolian processes Aeolian processes, also spelled eolian, pertain to wind activity in the study of geology and weather and specifically to the wind's ability to shape the surface of the Earth (or other planets). Winds may erode, transport, and deposit materials ...

(wind-deposited) approximately 275 million years ago. Several structural features such as

ripple marks In geology, ripple marks are sedimentary structures (i.e., bedforms of the lower flow regime) and indicate agitation by water ( current or waves) or wind. Defining ripple cross-laminae and asymmetric ripples * ''Current ripple marks'', ''u ...

, sand dune deposits, rain patches, slump marks, and fossil tracks are not only well preserved within the formation, but also contribute evidence of its eolian origin.McKee, E.D. (1945
''Small-scale structures in the Coconino Sandstone of northern Arizona."''
The Journal of Geology. 53(5):313–325.McKee, E.D. (1979
''A study of global sand seas.''
Professional Paper 1052. U.S. Geological Survey, Reston, Virginia. 429 pp.Middleton, L.T., D.K. Elliott, and M. Morales (2002) ''Coconino Sandstone,'' in S.S. Beus and M. Morales, eds., ''Grand Canyon Geology.'' Oxford University Press, New York.

Lechatelierite Lechatelierite is silica glass, amorphous SiO2, non-crystalline mineraloid. Structure Lechatelierite is a mineraloid as it does not have a crystal structure. Although not a true mineral, it is often classified in the quartz mineral group. Formati ...

(silica glass), as well as

coesite Coesite is a form ( polymorph) of silicon dioxide Si O2 that is formed when very high pressure (2–3 gigapascals), and moderately high temperature (), are applied to quartz. Coesite was first synthesized by Loring Coes Jr., a chemist at the ...

and stishovite (high pressure forms of SiO₂) were formed during the impact of a meteorite into the Coconino Sandstone at Barringer Crater in

.Kieffer, S.W. (1971
''Shock metamorphism of the Coconino sandstone at Meteor Crater.''
Arizona, Journal of Geophysical Research. 76(23):5449-5473.Kieffer, S.W. (1971
''I, Shock Metamorphism of the Coconino Sandstone at Meteor Crater, Arizona; II, The Specific Heat of Solids of Geophysical Interest.''Unpublished PhD. dissertation.
Department of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California. 253 pp.

Geological sequences

Sequence of layers: Coconino Sandstone on Hermit Shale on sloping redbeds of Supai Group.

References

External links

* Anonymous (nd
Coconino Formation
West Coast Regional Carbon Sequestration Partnership (WESTCARB). * U.S. Geological Survey (2011

U.S. Department of the Interior, Denver, Colorado. {{Authority control Sandstone formations of the United States Natural history of the Grand Canyon Geologic formations of Arizona Geologic formations of Colorado Geologic formations of Nevada Geologic formations of Utah Geography of Coconino County, Arizona Permian Arizona Permian Colorado Permian geology of Nevada Permian geology of Utah Permian System of North America

Geological sequences

See also

References

External links