Finlay Limestone
The Finlay Limestone is a geologic formation in western Texas, southern New Mexico, and northern Chihuahua. It preserves fossils dating back to the early Cretaceous period.[1][2]
| Finlay Limestone | |
|---|---|
| Stratigraphic range: | |
 Limestone mountains of Finlay Limestone in Aquiles Serdán Municipality near Chihuahua City. | |
| Type | Formation |
| Unit of | Fredericksburg Group |
| Underlies | Del Norte Formation |
| Overlies | Cox Sandstone |
| Thickness | 130–426 feet (40–130 m) |
| Lithology | |
| Primary | Limestone |
| Other | Sandstone |
| Location | |
| Coordinates | 31.36°N 105.60°W |
| Region | New Mexico Texas Chihuahua |
| Country | United States Mexico |
| Type section | |
| Named for | Finlay Mountains |
| Named by | G.B Richardson |
| Year defined | 1904 |
  Finlay Limestone (the United States)  Finlay Limestone (Texas) | |
Description
The formation is composed of massive gray limestone with a few thin beds of brown sandstone, with a total thickness of 130–426 feet (40–130 m).[1][2] It is exposed in the Finlay Mountains (31.36°N 105.60°W),[1] the Sierra de Juarez,[3] and the Cerro de Cristo Rey uplift (31.787°N 106.546°W).[2] The formation overlies the Cox Sandstone[1] and is overlain by the Del Norte Formation.[2]
Fossils
The formation is highly fossiliferous, containing fossils characteristic of early Cretaceous Albian and Comanchean age.[2]
Economic resources
The formation includes carbonate replacement deposits of lead, zinc, and silver in northern Mexico, along the Chihuahua CRD belt.[4]
History of investigation
The formation was first defined by G.B. Richardson in 1904 and assigned to the Fredericksburg Group.[1]
Footnotes
- Richardson 1904
- Lovejoy 1976
- Kottlowski 1973
- Robertson, Ken; Megaw, Peter (June 2009). "Cinco de Mayo: A new silver, lead, and zinc discovery in northern Mexico". The Leading Edge. 28 (6): 730–735. doi:10.1190/1.3148416.
References
- Kottlowski, F.E. (1973). "Pre-Pliocene rocks in La Mesa region, southern Dona Ana County, New Mexico". El Paso Geological Society Field Trip Guidebook. 7: 37–46.
- Lovejoy, E.M.P. (1976). "Geology of Cerro de Cristo Rey uplift, Chihuahua and New Mexico" (PDF). New Mexico Bureau of Mines and Mineral Resources Memoir. 31. Retrieved 3 August 2020.
- Richardson, G.B. (1904). "Report of a reconnaissance in Trans-Pecos Texas north of the Texas and Pacific Railway". University of Texas, Mineral Survey Bulletin. 9.