Bluewater Creek Formation

Bluewater Creek Formation
Stratigraphic range: Carnian–Norian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Formation
Unit of	Chinle Group
Underlies	Petrified Forest Formation
Overlies	Shinarump Conglomerate
Thickness	100 meters (330 ft)
Lithology
Primary	Sandstone, mudstone
Other	Siltstone
Location
Coordinates	35.316381°N 108.059074°W / 35.316381; -108.059074
Region	New Mexico
Country	United States
Type section
Named for	Bluewater Creek
Named by	Lucas and Hayden
Year defined	1989
Bluewater Creek Formation (the United States) Show map of the United States Bluewater Creek Formation (New Mexico) Show map of New Mexico

The Bluewater Creek Formation is a geologic formation in west-central New Mexico. It preserves fossils dating back to the late Triassic period.^[1]

Description

The formation consists of red sandstones and mudstones and has a total thickness in excess of 100 meters (330 ft). It conformably overlies the Shinarump Conglomerate and conformably underlies the Petrified Forest Formation.^[1]

The formation has been correlated with the Salitral Formation of north-central New Mexico on the basis of its lithology, but it is likely somewhat younger, with an age around 219 million years.^[2]

Fossils

The formation contains some fossil vertebrates and an extensive fossil flora.^[1] Fossil tetrapods from the Bluewater Creek Formation include the theropod dinosaur Camposaurus, phytosaur Rutiodon, the aetosaurs Desmatosuchus and Stagonolepis, and the metoposaurid Anaschisma. These are characteristic of the late Carnian.^[3]

History of investigation

Spencer G. Lucas and S.N. Hayden defined the Bluewater Creek Member of the Chinle Formation in 1989, assigning to it beds formerly assigned either to Division D, lower red member, or Monitor Butte Member of the Chinle Formation.^[1] With their subsequent promotion of the Chinle in northwestern New Mexico to group rank, the Bluewater Creek was promoted to the Bluewater Creek Formation.^[3]

On the basis of high-precision detrital zircon geochronology, Ramezani, Fastovsky, and Bowring concluded in 2014 that the Bluewater Creek beds are correlative with the uppermost Blue Mesa Member to middle Sonsela Member of the Chinle Formation of the Petrified Forest National Park in Arizona, and recommended that the formation be abandoned.^[4]

See also

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

References

1. Lucas, S.G.; Hayden, S.N. (1989). "Triassic stratigraphy of west-central New Mexico" (PDF). New Mexico Geological Society Field Conference Guidebook. 40: 191–211. Retrieved 3 August 2020.
2. Zeigler, Kate E.; Geissman, John W. (June 2011). "Magnetostratigraphy of the Upper Triassic Chinle Group of New Mexico: Implications for regional and global correlations among Upper Triassic sequences". Geosphere. 7 (3): 802–829. doi:10.1130/GES00628.1.
3. Lucas, S.G.; Heckert, Andrew B. (May 1997). "Triassic stratigraphy and paleontology on the Fort Wingate quadrangle, west-central New Mexico". New Mexico Geology. 19 (2). Retrieved 3 August 2020.
4. Ramezani, J.; Fastovsky, D. E.; Bowring, S. A. (1 June 2014). "Revised chronostratigraphy of the Lower Chinle Formation strata in Arizona and New Mexico (USA): High-precision U-Pb geochronological constraints on the Late Triassic evolution of dinosaurs". American Journal of Science. 314 (6): 981–1008. doi:10.2475/06.2014.01.