Earth:Edith Formation
| Edith Formation Stratigraphic range: Late Pleistocene–Middle Pleistocene | |
|---|---|
| Type | Formation |
| Overlies | Arroyo Ojito Formation, Sierra Ladrones Formation |
| Thickness | 10–40 feet (3.0–12.2 m) |
| Lithology | |
| Primary | Gravel |
| Location | |
| Coordinates | [ ⚑ ] 35°09′07″N 106°39′29″W / 35.152°N 106.658°W |
| Region | New Mexico |
| Country | United States |
| Type section | |
| Named for | Edith Boulevard in Albuquerque, New Mexico |
| Named by | P.W. Lambert |
| Year defined | 1968 |
  Edith Formation (the United States)  Edith Formation (New Mexico) | |
The Edith Formation is a fluvial gravel Pleistocene geologic formation exposed near Albuquerque, New Mexico.[1][2]
Description
The Edith Formation consists of a single upward fining sequence, with a gravel base and overlying sandy to muddy floodplain deposits. It is poorly to moderately consolidated and locally cemented brown gravel, sand, and sandy clay. A typical composition for the basal gravel is 30% quartzite and 40% volcanic rock, with smaller amounts of granite and metamorphic and sedimentary rocks. It contains sparse clasts of densely welded Bandelier Tuff.[1]
The formation extends at least from near Algodones to Albuquerque and forms a distinctive regional marker bed, cropping out along the inner valley escarpment of the Rio Grande. Its thickness is 10–40 feet (3.0–12.2 m). Its upper contact is marked by a diatomite bed and it unconformably rests on the Arroyo Ojito and Sierra Ladrones Formations, with a weakly developed paleosol (fossil soil) at the contact. The base of the formation defines a prominent strath (fossil floodplain) some 40–80 feet (12–24 m) above the present Rio Grande floodplain.[1]
The formation was initially interpreted as a late Pleistocene terrace of the most recent glaciation.[3] More recent work extends its temporal range into the middle Pleistocene.[4]
Formations
The Edith Formation contains fossils characteristic of the Rancholabrean North American land mammal age, including Bison, Mastodon, Camelops, and Equus.[2]
History of investigation
The unit was first defined by P.W. Lambert in his dissertation on the Quaternary geology of Albuquerque in 1968, and named for nearby Edith Boulevard.[3]
See also
- List of fossiliferous stratigraphic units in New Mexico
- Paleontology in New Mexico
Footnotes
References
- Connell, Sean D.; Love, David W. (2001). "Stratigraphy of middle and upper Pleistocene fluvial deposits of the Rio Grande (post-Santa Fe Group) and the geomorphic development of the Rio Grande Valley, Northern Albuquerque Basin, Central New Mexico". New Mexico Bureau of Geology and Mineral Resources Open File Reports 454B: 167–178. https://geoinfo.nmt.edu/publications/openfile/downloads/400-499/454/papers/OFR454B_pdf/J-Connell_QuaternaryTerrace.pdf. Retrieved 31 July 2020.
- Connell, S.D.; Love, D.W.; Dunbar, N.W. (February 2007). "Geomorphology and stratigraphy of inset fluvial deposits along the Rio Grande valley in the central Albuquerque Basin, New Mexico". New Mexico Geology 29 (1): 13–31. https://geoinfo.nmt.edu/publications/periodicals/nmg/29/n1/nmg_v29_n1_p13.pdf. Retrieved 7 February 2022.
- Lambert, P.W. (1968). Quaternary stratigraphy of the Albuquerque area, New Mexico [Ph.D. dissertation]. Albuquerque: University of New Mexico.
- Lucas, S.G.; Williamson, T.E.; Sobus, J. (1988). "Late Pleistocene (Rancholabrean) mammals from the Edith Formation, Albuquerque, New Mexico". The New Mexico Journal of Science 28 (1): 51–58.
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