Precambrian Fossil Record (4.6 Ga–541 Ma)
Precambrian Fossil Record (4.6 Ga–541 Ma)
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An Official Wyoming Government Website
Precambrian time scale showing significant geologic events and paleoenvironments in Wyoming as well as characteristic life throughout geologic history (modified from Hager, 1970).
The Precambrian Era began with the formation of the earth and lasted about 3.5 billion years, which accounts for nearly 80 percent of the entire geologic time scale. Evidence of life appears in the early Archean eon, but the fossil record at that time is rare. By the Late Archean, stromatolites (microbial mat-like structures) started to appear in the rock record. Stromatolites are the most common Precambrian fossils.
In Wyoming, stromatolites are found in the Snowy Range (Medicine Bow Mountains) in the Nash Fork Formation of the Libby Creek Group. The stromatolites started out as microbial mats that colonized in a continental shelf environment. They are believed to have formed ~1.7 billion years ago (~1,700 Ma).
Stromatolites of the Medicine Bow Mountains, Wyo.
Distribution of Precambrian rocks across Wyoming.
References
References
Branson, E.B., and Mehl, M.G., 1932, Footprint records from the Paleozoic and Mesozoic of Missouri, Kansas, and Wyoming: Bulletin of the Geological Society of America [Geological Society of America Bulletin] v. 43, 10 pl., p. 383–398.
Lovelace, D.M., and Lovelace, S.D., 2012, Paleoenvironments and paleoecology of a Lower Triassic invertebrate and vertebrate ichnoassemblage from the Red Peak Formation (Chugwater Group), Central Wyoming: Palaios, v. 27, p. 636–657.
Contact:
Colby Schwaderer, colby.schwaderer@wyo.gov
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