Article · Wikipedia archive · Last revised Jul 19, 2026

Thaynes Limestone

The Thaynes Formation is a geologic formation in Montana and Idaho, United States. It was recently elevated to group status, as the Thaynes Group.

Last revised
Jul 19, 2026
Read time
≈ 1 min
Length
182 w
Citations
2
Source
Thaynes Formation
Stratigraphic range: Triassic
TypeFormation
UnderliesAnkareh Formation
OverliesWoodside Formation
Lithology
PrimaryLimestone
Location
RegionMontana, Idaho, Wyoming
CountryUnited States
Thaynes Limestone within Green River Basin stratigraphy source ↗

The Thaynes Formation is a geologic formation in Montana and Idaho, United States. It was recently elevated to group status, as the Thaynes Group.1

It preserves fossils dating back to the Triassic period, such as Ammonoidea, Actinopterygii, Actinistia, Conodonta, Gastropoda, Nautiloidea, Ichthyosauria, and others. A diverse fauna known as the Paris biota2 has been described from the Thaynes Formation.

See also

See also

References

References

  1. Lucas, Spencer G.; Krainer, Karl; Milner, Andrew R. C. (2007). "The type section and age of the Timpoweap Member and stratigraphic nomenclature of the Triassic Moenkopi Group in Southwestern Utah". New Mexico Museum of Natural History and Science Bulletin. 40: 109–117.
  2. Brayard et al. (2017): Unexpected Early Triassic marine ecosystem and the rise of the Modern evolutionary fauna. Science Advances 3 (2):e1602159; doi:10.1126/sciadv.1602159 https://www.science.org/doi/10.1126/sciadv.1602159