The Garita Creek Formation is a geologic formation in New Mexico that contains vertebrate fossils characteristic of the Carnian Age of the late Triassic .

The formation may be synonymous with the Tecovas Formation in Texas.

Description

The formation consists mostly of gray red to red or mottled gray green mudstone containing limestone nodules. About 25% of the formation is massive fine-grained laminar gray red sandstone. It rests conformably on the Santa Rosa Formation, and is overlain disconformably by the Trujillo Formation. The total thickness of the formation is 122–152 meters (400–499 ft). It is exposed throughout the drainage of the Conchas River and its tributaries west to the Sangre de Cristo Mountains.

Fossils

The formation contains vertebrate fossils of Desmatosuchus, Typothorax, Paratypothorax, Postosuchus, rauisuchians, metoposaurids, Ceratodus, and indeterminate phytosaurs. Drepanosaurids, including Unguinychus and at least one other unnamed species, have been described from the formation's Homestead Site.

History of investigation

The formation was first named by Lucas and Hunt in 1989 for beds formerly assigned to the informal lower shale member of the Chinle Formation in the Tucumcari Basin. The formation definition has been criticized as a junior synonym for the Tecovas Formation across the border in Texas.

See also

Footnotes

  • Lehman, T.M. (1994). (PDF). New Mexico Bureau of Mines & Mineral Resources Bulletin. 150: 37–51.
  • Lucas, S.G.; Hunt, A.P. (1989). . In Lucas, S.G.; Hunt, A.P. (eds.). Dawn of the age of dinosaurs in the American southwest. New Mexico Museum of Natural History and Science. pp. 150–170.
  • Lucas, S.G.; Hunt, A.P.; Huber, P. (1990). (PDF). New Mexico Geological Society Field Conference Guidebook. 41: 305–318.