Willow Tank Formation

Willow Tank Formation
Stratigraphic range: Late Cretaceous, Cenomanian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Underlies	Baseline Sandstone[1]
Overlies	Aztec Sandstone[2]
Thickness	unknown
Lithology
Primary	Claystone, conglomerate, sandstone
Location
Coordinates	36°27′22″N 114°31′59″W
Approximate paleocoordinates	20.8°N 53.4°W / 20.8; -53.4
Region	Nevada
Country	United States
Extent	Valley of Fire, Nevada

The Willow Tank Formation is a geologic formation which outcrops in the U.S. state of Nevada. Initially believed to be of Early Cretaceous (Albian) age,^[3] later studies have concluded that it was more likely to be of Late Cretaceous (Cenomanian) age,^[4][5][6][7] making it equivalent to the Cloverly and Cedar Mountain Formations. It was deposited in an anastomosed fluvial system.^[3]

Paleofauna

All paleofauna listed are taken from a list compiled by Bonde (2008a)^[3] unless stated otherwise.

Non-dinosaurs

• cf. Adocus
• Baena sp.
• Ceratodus sp.
• Coprolites (indet.)
• Crocodyliformes indet.
• Gastropoda indet.
• Holostei indet.
• Lepisosteidae indet.
• Naomichelys sp.
• Scoyenia sp.
• Trionychidae (?) indet.

Dinosaurs

• Dromaeosauridae indet.
• Iguanodontia indet.
• Macroelongatoolithus carlylei^[1]
• Nevadadromeus schmitti^[7]
• Ornithopoda indet.^[8]
• Theropoda indet.
• Titanosauriformes indet.
• Thyreophora indet.
• Tyrannosauroidea indet.

References

1. Bonde, Joshua W.; Varricchio, David J.; Jackson, Frankie D.; Loope, David B.; Shirk, Aubrey M. (2008b), "Dinosaurs and dunes! Sedimentology and paleontology of the Mesozoic in the Valley of Fire State Park", GSA Field Guide 11: Field Guide to Plutons, Volcanoes, Faults, Reefs, Dinosaurs, and Possible Glaciation in Selected Areas of Arizona, California, and Nevada, vol. 11, Geological Society of America, pp. 249–262, doi:10.1130/2008.fld011(11), ISBN 978-0-8137-0011-3, retrieved October 22, 2022
2. Longwell, C.R. (1949). "Structure of the Northern Muddy Mountain Area, Nevada". Geological Society of America Bulletin. 60 (5): 923–968. Bibcode:1949GSAB...60..923L. doi:10.1130/0016-7606(1949)60[923:SOTNMM]2.0.CO;2. ISSN 0016-7606. Wikidata Q60182382.
3. William., Bonde, Joshua (2008a). Paleoecology and taphonomy of the Willow Tank Formation (Albian), Southern Nevada. OCLC 302295902.
4. "Lake Mead G-E-M resources area (GRA no. NV-35) : Technical report (WSAs NV 050-0231, 050–0233, 050–0235, 050–0236, and 050-0238) : Final report" (PDF).
5. "Nellis/Quail Spring G-E-M resources area (GRA no. NV-33) : Technical report (WSAs NV 050-0411, 050-04R-15A, B, and C) : Final report" (PDF).
6. "Muddy Mountains G-E-M resources area (GRA no. NV-34) : Technical report (WSA NV 050-0229) : Final report" (PDF).
7. Bonde, Joshua W.; Hall, Rebecca L.; Krumenacker, L. J.; Varricchio, David J. (2022). "Nevadadromeus schmitti (gen. et sp. nov.), a New Basal Neornithischian with Affinities to the Thescelosaurinae, from the Upper Cretaceous (Cenomanian) Willow Tank Formation of Southern Nevada". Journal of the Arizona-Nevada Academy of Science. 50 (1): 1–8. doi:10.2181/036.050.0101. ISSN 0193-8509. S2CID 252931645.
8. Humphrey, Rebecca (2017). "Late Cretaceous Ornithopod Dinosaur Fossil Assmblege from the Willow Tank Formation of Southeastern Nevada". Geological Society of America Abstracts with Programs. Geological Society of America. doi:10.1130/abs/2017cd-293081.