Zuni Sandstone
The Zuni Sandstone is a geologic formation in west-central New Mexico. It marks the southernmost limit of Jurassic fluvial and lacustrine sedimentary formations, which pinch out to become a single sandstone body.
| Zuni Sandstone Stratigraphic range: middle Jurassic | |
|---|---|
 Outcrop of Zuni Sandstone at El Malpais National Monument, New Mexico | |
| Type | Formation |
| Sub-units | San Rafael Group |
| Underlies | Dakota Formation |
| Overlies | Chinle Group. Wingate Sandstone |
| Thickness | 150 m (490 ft) |
| Lithology | |
| Primary | Sandstone |
| Location | |
| Coordinates | 35.0525°N 108.7957°W |
| Region | New Mexico |
| Country | United States |
| Type section | |
| Named for | Zuni Plateau |
| Named by | Clarence Dutton |
| Year defined | 1885 |
  Zuni Sandstone (the United States)  Zuni Sandstone (New Mexico) | |
Description
The Zuni Sandstone is found south of the I-40 corridor in west-central New Mexico. At about this latitude, the Todilto, Morrison, and Summerville Formations pinch out to leave a Jurassic section that is almost entirely composed of eolian sandstone. This is designated as the Zuni Sandstone, which is thus the lateral equivalent of the combined Entrada and Bluff Formations.[1]
At the type section at Dowa Yalaane (Taaiyalone Mesa), the formation consists of about 80 meters (260 ft) of eolian sandstone corresponding to the Entrada Formation. A break corresponds to the pinched-out Todilto and Summerville Formations. Above this is about 60 meters (200 ft) of sandstone corresponding to the Bluff Formation. Then comes a break corresponding to the pinchout of the Recapture Member of the Morrison Formation, another sandstone interval corresponding to the Acoma Tongue of the Zuni Sandstone, and a final break corresponding to the pinchout of the remaining Morrison Formation. The Zuni Formation unconformably rests on the Wingate Sandstone or Chinle Group and is unconformably overlain by the Dakota Formation.[2][1]
History of investigation
The unit was first described by Clarence Dutton in 1885.[3] However, A.A. Baker, C.H. Dane, and J.B. Reeside regarded it as identical to the Morrison Formation.[4] R.J. Hackman and A.B. Olson renamed the beds as the Cow Springs Sandstone in 1977[5] O.J. Anderson proposed the modern definition of the formation in 1983.[2]
References
- Lucas, Spencer G. (2020). "Jurassic stratigraphy of the southeastern Colorado Plateau, west-central New Mexico: 2020 synthesis" (PDF). New Mexico Geological Society Special Publication. 14: 135–144. Retrieved 30 October 2020.
- Anderson, O.J. (1983). "Preliminary report on redefinition of Zuni Sandstone, west-central New Mexico" (PDF). New Mexico Geology. 5 (3): 56–60. Retrieved 29 October 2020.
- Dutton, C.E. (1885). "Mount Taylor and the Zuni plateau". U.S. Geological Survey Annual Report. 6: 113–198. Retrieved 29 October 2020.
- Baker, A.A.; Dane, C.H.; Reeside, J.B., Jr. (1936). "Correlation of the Jurassic formations of parts of Utah, Arizona, New Mexico, and Colorado". U.S. Geologic Survey Professional Paper. 183. doi:10.3133/pp183.
- Hackman, R.J.; Olson, A.B. (1977). "Geology, structure, and uranium deposits of the Gallup 1 degree x 2 degrees quadrangle, New Mexico and Arizona". U.S. Geological Survey Miscellaneous Investigations Series Map. I-981. Retrieved 29 October 2020.