Willow Tank Formation Explained

Willow Tank Formation
Type:	Geological formation
Age:	Late Cretaceous,
Period:	Cenomanian
Prilithology:	Claystone, conglomerate, sandstone
Region:	Nevada
Country:	United States
Coordinates:	36.4561°N -114.5331°W
Paleocoordinates:	20.8°N -53.4°W
Underlies:	Baseline Sandstone
Overlies:	Aztec Sandstone^[1]
Thickness:	unknown
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, later studies have concluded that it was more likely to be of Late Cretaceous (Cenomanian) age,^{[2] [3] [4]} making it equivalent to the Cloverly and Cedar Mountain Formations. It was deposited in an anastomosed fluvial system.

Paleofauna

All paleofauna listed are taken from a list compiled by Bonde (2008a)^[5] 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
• Nevadadromeus schmitti^[6]
• Ornithopoda indet.^[7]
• Theropoda indet.
• Titanosauriformes indet.
• Thyreophora indet.
• Tyrannosauroidea indet.

Notes and References

1. Longwell, C.R..
2. Web site: 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 .
3. Web site: 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 .
4. Web site: Muddy Mountains G-E-M resources area (GRA no. NV-34) : Technical report (WSA NV 050-0229) : Final report .
5. Book: William., Bonde, Joshua . Paleoecology and taphonomy of the Willow Tank Formation (Albian), Southern Nevada . 2008a . 302295902.
6. 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 . 10.2181/036.050.0101 . 252931645 . 0193-8509.
7. Humphrey . Rebecca . Late Cretaceous Ornithopod Dinosaur Fossil Assmblege from the Willow Tank Formation of Southeastern Nevada . 2017 . Geological Society of America Abstracts with Programs . Geological Society of America . 10.1130/abs/2017cd-293081.