Smeltertown Formation

Smeltertown Formation
Stratigraphic range: Albian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Underlies	Muleros Formation
Overlies	Del Norte Formation
Thickness	193 feet (59 m)
Lithology
Primary	Shale
Other	Siltstone, sandstone
Location
Coordinates	31°47′39″N106°32′35″W / 31.7940792°N 106.5430513°W / 31.7940792; -106.5430513
Region	New Mexico
Country	United States
Type section
Named for	Smeltertown
Named by	W.S. Strain
Year defined	1976
Smeltertown Formation (the United States) Show map of the United States Smeltertown Formation (New Mexico) Show map of New Mexico

The Smeltertown Formation is a geologic formation in New Mexico, which is particularly well exposed at Cerro de Cristo Rey near El Paso, Texas. It preserves fossils dating back to the early Cretaceous period. ^[1]

Description

The formation consists of gray shale with some interbedded siltstone and silty limestone, with some fine grained sandstone towards the top of the formation. The total thickness is 193 feet (59 m). It rests conformably on the Del Norte Formation and is conformably overlain by the Muleros Formation. ^[1]

Fossils

Fossils are uncommon in the formation. ^[1] However, the rare nautiloid Cymatoceras cf. C. Loeblichi Miller and Harris has been recovered from the formation, ^[2] as have fossil ophiuroids (brittle stars). ^[3] The formation is also the type location for the bryozoan Reptomulticava texana. The distribution of foram fossils in the formation (planktonic species more common towards the bottom and benthic species more common towards the top) suggests that the sea in the area was shallowing during deposition of the formation. ^[4]

See also

• Earth sciences portal
• Paleontology portal

• List of fossiliferous stratigraphic units in New Mexico
• Paleontology in New Mexico

Footnotes

1. Strain, W.S. (1976). "New formation names in the Cretaceous at Cerro de Cristo Rey, Dona Ana County, New Mexico; Appendix 2" (PDF). New Mexico Bureau of Mines and Mineral Resources Memoir. 31: 77–82. Retrieved 5 August 2020.
2. Sealey, Paul L.; Lucas, Spencer G.; Durney, Kevin (2018). "The rare early Cretaceous (late Albian) nautiloid Cymatoceras cf. C. Loeblichi Miller and Harris from Cerro de Cristo Rey, Dona Ana County, New Mexico". New Mexico Museum of Natural History and Science Bulletin. 80: 659–666. Retrieved 16 September 2020.
3. Cornell, William C.; Lemone, David V.; Norland, William D. (November 1991). "Albian ophiuroids from Cerro de Cristo Rey, Dona Ana County, New Mexico". Journal of Paleontology. 65 (6): 1009–1013. doi:10.1017/S0022336000033321.
4. Nye, Osborne B.; Lemone, David V. (1978). "Multilaminar Growth in Reptomulticava texana, a New Species of Cyclostome Bryozoa". Journal of Paleontology. 52 (4): 830–845. JSTOR   1303903.