A geologic formation in New Mexico
| Diamond Tail Formation | |
|---|---|
| Stratigraphic range: late Paleocene–early Eocene PreꞒ Ꞓ O S D C P T J K Pg N | |
 Exposure of Diamond Tail Formation on Cerro Colorado, near Lamy, New Mexico | |
| Type | Formation |
| Underlies | Galisteo Formation |
| Overlies | Menefee Formation |
| Thickness | 442 m (1,450 ft) |
| Lithology | |
| Primary | Sandstone |
| Other | Mudstone |
| Location | |
| Region | Central New Mexico |
| Country | United States |
| Type section | |
| Named for | Diamond Tail Ranch |
| Named by | Lucas, Cather, Abbott, and Williamson |
| Year defined | 1997 |
  Diamond Tail Formation (the United States)Show map of the United States Diamond Tail Formation (New Mexico)Show map of New Mexico | |
The Diamond Tail Formation is a geologic formation in New Mexico. It contains fossils characteristic of the late Paleocene or early Eocene.
Description
The Diamond Tail Formation consists of a lower member composed of sandstone and conglomeratic sandstone, a middle member of variegated mudstone, and an upper sandstone member. The formation crops out over a limited area between Sandia Crest and the southern Sangre de Cristo Mountains.
The formation is cut by thrust and strike-slip faults consistent with east-northeast to east-trending tectonic compression of the late stages of the Laramide Orogeny.
The formation likely correlates with the lower San Jose Formation of the San Juan Basin.
Fossils
The presence of Hyracotherium teeth dates the formation to the late Paleocene or early Eocene.
History
The beds now designated as the Diamond Tail Formation were originally part of F.V. Hayden's Galisteo sand group. By 1997, it was clear that these beds were separated from the remainder of the Galisteo by a significant regional unconformity, and they were split off into the Diamond Tail Formation, named after exposures near Diamond Tail Ranch.
Footnotes
References
- Erslev, Eric A. (1 January 2001). "Multistage, multidirectional Tertiary shortening and compression in north-central New Mexico". GSA Bulletin. 113 (1): 63–74. doi:10.1130/0016-7606(2001)113<0063:MMTSAC>2.0.CO;2.
- Hayden, F.V. (1869). United States Geologic Survey of New Mexico and Colorado.
- Lucas, Spencer G.; Cather, Steven M.; Abbott, John C.; Williamson, Thomas E. (November 1997). "Stratigraphy and tectonic implications of Paleogene strata in the Laramide Galisteo Basin, north-central New Mexico" (PDF). New Mexico Geology.
