A geologic formation in New Mexico
| Edith Formation | |
|---|---|
| Stratigraphic range: Late Pleistocene–Middle Pleistocene PreꞒ Ꞓ O S D C P T J K Pg N ↓ | |
| 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 / 35.152; -106.658 |
| 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)Show map of the United States Edith Formation (New Mexico)Show map of New Mexico | |
The Edith Formation is a fluvial gravel Pleistocene geologic formation exposed near Albuquerque, New Mexico.
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.
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.
The formation was initially interpreted as a late Pleistocene terrace of the most recent glaciation. More recent work extends its temporal range into the middle Pleistocene.
Formations
The Edith Formation contains fossils characteristic of the Rancholabrean North American land mammal age, including Bison, Mastodon, Camelops, and Equus.
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.
See also
Footnotes
- ^ Connell & Love 2001.
- ^ Lucas, Williamson & Sobus 1988.
- ^ Lambert 1968.
- Connell, Love & Dunbar 2007.
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" (PDF). New Mexico Bureau of Geology and Mineral Resources Open File Reports. 454B: 167–178. Retrieved July 31, 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" (PDF). New Mexico Geology. 29 (1): 13–31. Retrieved February 7, 2022.
- Lambert, P.W. (1968). Quaternary stratigraphy of the Albuquerque area, New Mexico . 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.