Williams Fork Formation
| Williams Fork Formation | |
|---|---|
| Stratigraphic range: Campanian (Edmontonian) ~ | |
| Type | Geological formation |
| Unit of | Mesaverde Group |
| Lithology | |
| Primary | Mudstone |
| Other | Sandstone |
| Location | |
| Coordinates | 40°00′N 108°48′W / 40.0°N 108.8°W |
| Approximate paleocoordinates | 47°30′N 80°18′W / 47.5°N 80.3°W |
| Region | Colorado |
| Country | United States |
Williams Fork Formation (the United States) Williams Fork Formation (Colorado) | |
The Williams Fork Formation (WFF) is a geologic formation located in northwestern Colorado that is a member of the Mesaverde group. The formation was located on the eastern coast of Laramidia and was deposited by a fluvio-deltaic environment during the Campanian/Maastrichtian (Edmontonian) boundry.
Geology
The Williams Fork Fomation is located on in Northwestern Colorado. It is a member of the Mesaverde group. The formation compared to similar formations of similar age on the Laramidian continent is understudied.[1] The formations fluvial deposits include isolated and stacked point-bar deposits, crevasse splays and overbank/floodplain mudrock. It contains highly discontinuous fluvial sandstones, associated siltstones, shales and deposits of coal.[2]
The formation is fossiliferous having yielded a diverse assemblage of thousands vertebrate fossils. The formations has an abundance of teeth fossils.
Paleoenvironment
During the Late Cretaceous period (at the boundary of the Campanian and Maastrichtian), North America was divided into two continents, Laramidia and Appalachia, by a seaway called the Western Interior Seaway. The Williams Fork Formation was located on the eastern coast of Laramidia.[2]
Fauna
This formation is very fossiliferous with many different species that have been discovered. It supported a diverse group of vertebrates that included fish, lissamphibians, squamates, turtles, eusuchians, dinosaurs, mammals, insect feeding traces on leaves, freshwater mollusks, etc.[1]
Reptiles
Reptiles in the Williams Forks Formation are abundant. Squamates like the genus Peneteius lived here.[3]
Dinosaurs
Many groups of dinosaurs have been discovered here including tyrannosaurids, dromaeosaurids, troodontids, nodosaurids, ankylosaurids, and hadrosaurids. Pentaceratops sternbergii is one of the most notable dinosaurs found at this formation.[4] Intermediate fossils of Dromeosaurs such as Richardoestesia has been discovered.[3]
Crocodylomorphs
The teeth of Alligatoroids are relatively common and are extremely similar to Brachychampsa which lived at the same time. Though they are considered intermediate in general features.[3]
Mammals
The formation contains several Metathrian mammals like Heleocola and Glasbius. Isolated teeth remains show that Multituberculate mammals existed to with genera like Meniscoessus.[5][6][7]
Fish
The freshwater biota of the Williams Fork formation is dominated by Actinopterygian fishes. These fishes include Holosteans such as Atractosteus, amiids such as Melvius, Cyclurus and Palaeolabrus. Chondrosteans are only represented tentatively by a acipenserid. This formation also has many Teleosteomorphs like Belonostomus, Paralbula casei, Coriops, Estesesox foxi, Acronichthys, hiodontids, and acanthomorphs. There have also been fragmentary remains of what may be a pycnodontiform. The teeth of lungfish have been found.[3][8]
Chondrichthyans in the formation rare but does include hybodontids like Lonchidion and hemiscyllids like Chiloscyllium. Cantioscyllium was also discovered here. Rays like Cristomylus and Psuedomyledaphus have been reported.[8]
Invertebrates
Ammonites such as the genus Lewyites were found in the formation.
See also
References
- ^ a b Hunt-Foster, ReBecca (2025-05-20). "THE UPPER CRETACEOUS WILLIAMS FORK FORMATION (LATE CRETACEOUS: CAMPANIAN–MAASTRICHTIAN), NORTHWESTERN COLORADO, AND ITS PALEOECOLOGICAL IMPLICATIONS FOR LARAMIDIA". GSA.
{{cite journal}}: Cite journal requires|journal=(help) - ^ a b Pranter, Matthew J; Vargas, Marielis F; Davis, Thomas L (2008-02-25). (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36 Citoid/WMF (mailto:noc@wikimedia.org)&ssu=&ssv=&ssw=&ssx=eyJyZCI6ImlvcC5vcmciLCJfX3V6bWYiOiI3ZjkwMDAwOGNjOTczMS1lNDFiLTQ1MDUtOTQxYy00YjYzNGY5YmU1OGUxLTE3NzE0NTE2OTk3MjQwLTAwMjU4NDJiMjkxNjM0YzU2YTQxMCIsInV6bXgiOiI3ZjkwMDA3NmMxOTE3My01NmI2LTQ4ZjgtOWQxOC1jMWI2YTNlOWY5YjQxLTE3NzE0NTE2OTk3MjQwLWYxYjY1OTMwYWEwNzNmNmYxMCJ9 "Characterization and 3D reservoir modelling of fluvial sandstones of the Williams Fork Formation, Rulison Field, Piceance Basin, Colorado, USA". Journal of Geophysics and Engineering. 5 (2): 158–172. doi:10.1088/1742-2132/5/2/003. ISSN 1742-2132.
{{cite journal}}: Check|url=value (help) - ^ a b c d www.semanticscholar.org https://www.semanticscholar.org/paper/New-Upper-Cretaceous-Microvertebrate-Assemblage-the-Brand-Heckert/8ef6c3262c7dfc33aca2df45b9c9e2ebd7e24e42. Retrieved 2026-02-18.
{{cite web}}: Missing or empty|title=(help) - ^ Diem, Steve; Archibald, James D. (2005). "Range extension of southern chasmosaurine Ceratopsian dinosaurs into northwestern Colorado". Journal of Paleontology. 79 (2): 251–258. Bibcode:2005JPal...79..251D. CiteSeerX 10.1.1.538.7263. doi:10.1666/0022-3360(2005)079<0251:REOSCC>2.0.CO;2. S2CID 17715685. Retrieved 21 September 2016.
- ^ Jubb Creek at Fossilworks.org
- ^ Rangely South (SDNHM) at Fossilworks.org
- ^ Eberle, Jaelyn; Cohen, Joshua; Foster, John; Hunt-Foster, ReBecca; Heckert, Andrew (2024). "A new Late Cretaceous metatherian from the Williams Fork Formation, Colorado". PloS One. 19 (10) e0310948. doi:10.1371/journal.pone.0310948. ISSN 1932-6203. PMC 11498682. PMID 39441759.
- ^ a b Crothers, Joel; Eberle, Jaelyn; Brinkman, Donald; Wurtz, Alyssa; Heckert, Andrew B.; Hunt-Foster, ReBecca K.; Foster, John R.; Dirkes, Ida C.; Dunn, Renee (2026-06-01). "An actinopterygian-dominated fish fauna from the Upper Cretaceous Williams Fork Formation, northwestern Colorado, and evidence for provinciality across Laramidia at the Campanian/Maastrichtian boundary". Cretaceous Research. 182 106313. doi:10.1016/j.cretres.2026.106313. ISSN 0195-6671.
Bibliography
- Weishampel, David B.; Dodson, Peter; Osmólska, Halszka, eds. (2004). The Dinosauria (2nd ed.). Berkeley: University of California Press. pp. 1–880. ISBN 0-520-24209-2. Retrieved 2019-02-21.
- Diem, Stephen Daniel. (1999). Vertebrate Faunal Analysis of the Upper Cretaceous Williams Fork Formation, Rio Blanco County, Colorado [Master's Thesis]. San Diego State University.
Further reading
- Archibald, J. D. (1987). Late Cretaceous (Judithian and Edmontonian) Vertebrates and Geology of the Williams Fork Formation. N.W. Colorado. In P. J. Currie, E. H. Koster, & Royal Tyrrell Museum of Palaeontology (Eds.), Fourth Symposium on Mesozoic Terrestrial Ecosystems: Drumheller, August 10–14, 1987: Short Papers (Rev. ed, pp. 7–11). Tyrrell Museum of Palaeontology.
- Brand, N., Heckert, A., Sanchez, I., Foster, J., Hunt-Foster, R., & Eberle, J. (2022). New Upper Cretaceous Microvertebrate Assemblage from the Williams Fork Formation, northwestern Colorado, U.S.A., and its Paleoenvironmental Implications. Acta Palaeontologica Polonica, 67(3), 579–600. https://doi.org/10.4202/app.00934.2021.
- Cifelli, R. L., Eberle, J. J., Lofgren, D. L., Lillegraven, J. A., & Clemens, W. A. (2004). Mammalian Biochronology of the Latest Cretaceous. In M. O. Woodburne (Ed.), Late Cretaceous and Cenozoic Mammals of North America: Biostratigraphy and Geochronology (pp. 21–42). Columbia University Press. https://www.jstor.org/stable/10.7312/wood13040.8.
- Diem, Stephen Daniel. (1999). Vertebrate Faunal Analysis of the Upper Cretaceous Williams Fork Formation, Rio Blanco County, Colorado [Master's Thesis]. San Diego State University.
- Noll, M. D. (1998). Sedimentology of the Upper Cretaceous Williams Fork Formation, Rio Blanco County, Northwestern Colorado [Master's Thesis]. San Diego State University. https://digitallibrary.sdsu.edu/islandora/object/sdsu%3A17
- J. R. Foster and R. K. Hunt-Foster. 2015. First report of a giant neosuchian (Crocodyliformes) in the Williams Fork Formation (Upper Cretaceous: Campanian) of Colorado. Cretaceous Research 55:66-73
- Lockley, M. G., Smith, J. A., & King, M. R. (2018). First reports of turtle tracks from the Williams Fork Formation ('Mesaverde' Group), Upper Cretaceous (Campanian) of western Colorado. Cretaceous Research, 84, 474–482. https://doi.org/10.1016/j.cretres.2017.11.001.
- W. J. Kennedy, W. A. Cobban, and G. R. Scott. 2000. Heteromorph ammonites from the Upper Campanian (Upper Cretaceous) Baculites cuneatus and Baculites reesidei zones of the Pierre Shale in Colorado, USA. Acta Geologica Polonica 50:1-20
- J. A. Lillegraven. 1987. Stratigraphic and evolutionary implications of a new species of Meniscoessus (Multituberculata, Mammalia) from the Upper Cretaceous Williams Fork Formation, Moffat County, Colorado. Dakoterra 3:46-56
- Sullivan, R.M., and Lucas, S.G. 2006. "The Kirtlandian land-vertebrate "age" – faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America." New Mexico Museum of Natural History and Science, Bulletin 35:7-29.