Abiquiu Formation

Abiquiu Formation
Stratigraphic range: Oligocene to Miocene
25–18.9 Ma
PreꞒ
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S
D
C
P
T
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K
Pg
N
Abiquiu Formation; Stratigraphic range: Oligocene to Miocene ; 25–18.9 Ma PreꞒ Ꞓ O S D C P T J K Pg N
	Abiquiu Formation at Plaza Blanca, north of Abiquiu, New Mexico
Type	Formation
Unit of	Santa Fe Group
Sub-units	Pedernal Chert
Underlies	Tesuque Formation
Overlies	El Rito Formation
Thickness	400 m (1,300 ft)
Lithology
Primary	Sandstone, siltstone
Other	conglomerate, mudstone
Location
Coordinates	36°14′24″N106°17′53″W / 36.240°N 106.298°W
Region	New Mexico
Country	United States
Type section
Named for	Abiquiu, New Mexico
Named by	H.T.U. Smith
Year defined	1938
	Abiquiu Formation (the United States) Abiquiu Formation (New Mexico)

Last updated November 14, 2021

From the White Place, painting by Georgia O'Keefe depicting the Abiquiu Formation From the White Place Georgia O'Keeffe.jpg — *From the White Place*, painting by Georgia O'Keefe depicting the Abiquiu Formation

The Abiquiu Formation is a geologic formation found in northern New Mexico. Radiometric dating constrains its age to between 18 million and 27 million years, corresponding to the late Oligocene to Miocene epochs.^[1]

Description

The Abiquiu Formation consists of light-gray to yellowish-gray, locally crossbedded, thin to thick beds of tuffaceous sandstone, pebbly sandstone, and siltstone. There are also a few gravel beds and lenses of mudstone. The clasts are mostly of volcanic rock, including Amalia Tuff and trachyandesite and trachydacite possibly also from the Latir volcanic field. The formation is exposed in a broad belt from the southwest flank of the Tusas Mountains to the Jarosa area in the northwest Jemez Mountains.^[5]^[6] The formation reaches a maximum thickness in excess of 400 meters (1,300 feet) near Cañones. The age of the formation is approximately bracketed by a lava flow near its top dated to 18.9 Ma and a 25 Ma flow near its base.^[1]

Both the lower contact of the formation with the Ritito Conglomerate and the upper contact with the Chama-El Rito Member of the Tesuque Formation are gradational. The transition to the Ritito Conglomerate is characterized by thick chert beds, informally designated the Pedernal chert for outcrops around Cerro Pedernal ( 36°09′47″N106°30′43″W / 36.163°N 106.512°W / 36.163; -106.512 ).^[1]

Individual beds in the formation thicken across the Canones fault zone, which separates the Colorado Plateau from the Rio Grande rift. This indicates that the formation was deposited after rifting began within the Rio Grande rift.^[1]

The formation correlates with the Cordito Member of the Los Pinos Formation.^[6] It can be divided into three intervals based on the source of its sediments. The first interval derives its sediments from basement rock of the Tusas Mountains and from the San Juan volcanic field. The second interval is rich in eroded Amalia Tuff and is interpreted as erosion of the edge of the Amalia outflow sheet. The third interval is entirely composed of debris of the Latir volcanic field. These intervals reflect development of the early Rio Grande rift, with the final interval showing that tilting to the east in the San Luis basin was initially slow enough that debris from the Latir field filled the basin and overflowed to the southwest.^[7]

History of investigation

The Abiquiu Tuff was first named by H.T.U. Smith in 1938 for exposures near the town of Abiquiu, New Mexico. Smith designated only a type area^[8] and no type locality has been defined.^[9] Fermor S. Church and John T. Hack recognized almost at once that the unit consisted of a lower conglomeratic member and an upper tuffaceous member separated by a chert horizon (the Pedernal chert member).^[2] L.A. Woodward and R.S. Timmer first referred to the unit as the Abiquiu Formation in 1979.^[10] In 2009, Florian Maldonado and Shari A. Kelley correlated the lower conglomerate beds with the Ritito Conglomerate and removed them from the formation, retaining Pedernal Chert as an informal name for the chert beds of the transition between the Ritito Conglomerate and Abiquiu Formation.^[3]

Cultural importance

Georgia O'Keeffe painted her landscape "From the White Place" in 1940 based on her study of the Abiquiu Formation at Plaza Blanca, and her studio at Abiquiu commanded a view of the Plaza Blanca outcrops to the north.^[4]

Footnotes

1 2 3 4 Maldonado & Kelley 2009, p. 6.
1 2 Church & Hack 1939.
1 2 Maldonado & Kelley 2009.
1 2 "From the White Place by Georgia O'Keeffe".
↑ Vazzana & Ingersoll 1981, p. 2467.
1 2 Maldonado & Kelley 2009, p. 5.
↑ Smith 1995.
↑ Smith 1938.
↑ GEOLEX: Abiquiu
↑ Woodward & Timmer 1979.

Related Research Articles

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The Sierra Blanca is an ultra-prominent range of volcanic mountains in Lincoln and Otero counties in the south-central part of the U.S. state of New Mexico. The range is about 40 miles (64 km) from north to south and 20 miles (32 km) wide.

Cerro Pedernal, locally known as just "Pedernal", is a narrow mesa in northern New Mexico. The name is Spanish for "flint hill". The mesa lies on the north flank of the Jemez Mountains, south of Abiquiu Lake, in the Coyote Ranger District of the Santa Fe National Forest. Its caprock was produced in the Jemez Volcanic Field. Its highest point is 9,862 feet.

The Caballo Mountains, are a mountain range located in Sierra and Doña Ana Counties, New Mexico, United States. The range is located east of the Rio Grande and Caballo Lake, and west of the Jornada del Muerto; the south of the range extends into northwest Doña Ana County. The nearest towns are Truth or Consequences and Hatch.

The Chamita Formation is a geologic formation in north-central New Mexico. It preserves unique fossils dating back to the Neogene period. The presence of volcanic ash beds in the formation, which can be radiometrically dated, gives the absolute age of the fossils, which is valuable for establishing the geologic time scale of the Neogene.

The Palm Park Formation is a geologic formation in southern New Mexico. It preserves fossils dating back to the Eocene epoch.

The Bandelier Tuff is a geologic formation exposed in and around the Jemez Mountains of northern New Mexico. It has a radiometric age of 1.85 to 1.25 million years, corresponding to the Pleistocene epoch. The tuff was erupted in a series of at least three caldera eruptions in the central Jemez Mountains.

The El Rito Formation is a geologic formation in New Mexico dating to the Eocene epoch. It records a time when sediments were trapped in deep basins in western North America rather than being carried downstream to the Gulf of Mexico, so that sediments of this age in the western Gulf are mostly from the Appalachian Mountains.

The Tanos Formation is a geologic formation in central New Mexico. It is estimated to be about 25 million years in age, corresponding to the Oligocene epoch.

The Ritito Conglomerate is a geologic formation in northern New Mexico dating to the Oligocene epoch.

The Polvadera Group is a group of geologic formations exposed in and around the Jemez Mountains of northern New Mexico. Radiometric dating gives it an age of 13 to 2.2 million years, corresponding to the Miocene through early Quaternary.

The Keres Group is a group of geologic formations exposed in and around the Jemez Mountains of northern New Mexico. Radiometric dating gives it an age of 13 to 6 million years, corresponding to the Miocene epoch.

The Puye Formation is a geologic formation exposed east of the Jemez Mountains of northern New Mexico. Radiometric dating constrains its age to between 5 and 2 million years, corresponding to the Pliocene epoch.

The Gilman Conglomerate is a geologic formation in northern New Mexico dating to the Oligocene epoch.

The Los Pinos Formation is a geologic formation in northern New Mexico. It was deposited from the late Oligocene through the late Miocene epochs, based on radiometric ages of interbedded lava flows and overlying and underlying formations.

The Amalia Tuff is a geologic formation exposed in and around Questa, New Mexico. It has a radiometric age of 25.39 ± 0.04 million years, corresponding to the Oligocene epoch.

The Latir volcanic field is a large volcanic field near Questa, New Mexico, that was active during the late Oligocene to early Miocene, 28 to 22 million years ago (Ma). It includes the Questa caldera, in whose deeply eroded interior is located the Molycorp Questa molybdenum mine.

The Blackshare Formation is a geologic formation exposed in the Hagan Basin west of the Ortiz Mountains of New Mexico. It is estimated be to of Miocene age.

The Picuris Formation is a geologic formation exposed in the eastern flank of the Rio Grande rift in northern New Mexico. It was deposited from the late Eocene to Miocene epochs.

The Bell Top Formation is a geologic formation in southern New Mexico. Radiometric dating of surrounding tuffs indicate that it was deposited in the Oligocene epoch.

References

Church, Fermor S.; Hack, John T. (August 1939). "An Exhumed Erosion Surface in the Jemez Mountains, New Mexico". The Journal of Geology. 47 (6): 613–629. Bibcode:1939JG.....47..613C. doi:10.1086/624816. S2CID 128546688.
Maldonado, Florian; Kelley, Shari A. (February 2009). "Revisions to the stratigraphic nomenclature of the Abiquiu Formation, Abiquiu and contiguous areas, north-central New Mexico" (PDF). New Mexico Geology. 31 (1): 3–8. Retrieved May 12, 2020.
Smith, Gary A. (1995). "Paleogeographic, volcanologic and tectonic significance of the upper Abiquiu Formation at Arroyo del Cobre, New Mexico" (PDF). New Mexico Geological Society Field Conference Series. 46: 261–270. Retrieved September 24, 2020.
Smith, Harold T. U. (October 1938). "Tertiary Geology of the Abiquiu Quadrangle, New Mexico". The Journal of Geology. 46 (7): 933–965. Bibcode:1938JG.....46..933S. doi:10.1086/624710. S2CID 140678910.
Vazzana, M. E.; Ingersoll, R. V. (December 1981). "Stratigraphy, Sedimentology, Petrology, and Basin Evolution of the Abiquiu Formation (Oligo-Miocene), North-Central New Mexico". GSA Bulletin. 92 (12_Part_II): 2401–2483. Bibcode:1981GSAB...92.2401V. doi:10.1130/GSAB-P2-92-2401.
Woodward, L.A.; Timmer, R.S. (1979). "Geology of the Jarosa quadrangle, New Mexico". New Mexico Bureau of Mines and Mineral Resources Geologic Map. 47. Retrieved August 10, 2020.

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[FOOTNOTEMaldonadoKelley20096-1] 1 2 3 4 Maldonado & Kelley 2009, p. 6.

[FOOTNOTEChurchHack1939-2] 1 2 Church & Hack 1939.

[FOOTNOTEMaldonadoKelley2009-3] 1 2 Maldonado & Kelley 2009.

[ftwp-4] 1 2 "From the White Place by Georgia O'Keeffe".

[FOOTNOTEVazzanaIngersoll19812467-5] Vazzana & Ingersoll 1981, p. 2467.

[FOOTNOTEMaldonadoKelley20095-6] 1 2 Maldonado & Kelley 2009, p. 5.

[FOOTNOTESmith1995-7] Smith 1995.

[FOOTNOTESmith1938-8] Smith 1938.

[geolex-abiquiu-9] GEOLEX: Abiquiu

[FOOTNOTEWoodwardTimmer1979-10] Woodward & Timmer 1979.

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