Caballero Formation
The Caballero Formation is a geologic formation found in the highlands flanking the southern Rio Grande River valley in New Mexico. It preserves fossils dating back to the Tournasian Age of the Carboniferous period.[1]
| Caballero Formation Stratigraphic range: Tournasian | |
|---|---|
| Type | Formation |
| Underlies | Lake Valley Limestone |
| Overlies | Percha Shale |
| Lithology | |
| Primary | Limestone |
| Other | Shale |
| Location | |
| Coordinates | 32.8592735°N 105.9187398°W |
| Region | New Mexico |
| Country | United States |
| Type section | |
| Named by | L.R. Laudon and A.L. Bowsher |
  Caballero Formation (the United States)  Caballero Formation (New Mexico) | |
Description
The Caballero Formation consists of nodular gray argillaceous limestone, which grades upward into nodular gray marl with shale lenses. It rests conformably on the Percha Shale and is overlain unconformably by the Lake Valley Limestone. The formation likely correlates with the Chouteau Limestone of the upper Mississippi valley.[1]
Fossils
The formation is locally abundant in fossils of Tournasian age.[1] These include the ammonoids Pericyclus blairi, P. Cooperi P. costulatus, and Gattendorfia bransoni as well as Tournasian conodont and brachiopod faunas.[2]
History of investigation
The beds forming this unit were originally included in the Devonian Percha Shale, but were separated into their own formation by Laudon and Bowsher in 1941, when it was recognized that they are Mississippian in age.[1]
References
- Laudon, L.R.; Bowsher, A.L. (1941). "Stratigraphy of the Mississippian formations of the Sacramento Mountains, New Mexico". Tulsa Geological Society Digest. 9: 73–75. Retrieved 29 July 2020.
- Mackenzie, Gordon, Jr. (1986). "Late Kinderhookian (Early Mississippian) ammonoids of the western United States". Paleontological Society Memoir. 19. JSTOR 1315530.
- Laudon and Bowsher 1941
- Mackenzie 1986