T-6: T(D) Hidden Pasture Spr. (Triassic of the United States)

Where: Montana (44.7° N, 112.8° W: paleocoordinates 14.3° N, 35.1° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Thaynes Formation, Spathian (251.3 - 247.2 Ma)

• Most recently, the Thaynes formation has been separated into four facies belts, which include a basinal facies, an outer shelf facies, an inner shelf facies, and a red bed facies. the basinal facies consists of dark grey to black very siltly lime mudstones and gray to loive drab siltstones and shales. The outer shelf facies belt is characterized by dark grayish brown whole fossil wackestone, ranging to light gray bioclastic grainstone, with minor interbedded sanstone, siltstone, and mudstone. The inner shelf facies includes a variety of lithologies, mainly fine-grained mudstone and silty limestone, along with less common dolomite, siltstone, and bioturbated mudstone.

• bed-level stratigraphic resolution

Environment/lithology: lithified limestone

• Sparcely fossiliferous limestone with a micritic matrix, which is possibly a more distal environment than setting C.

Size class: macrofossils

Preservation: mold/impression

Primary reference: J. K. Schubert and D. J. Bottjer. 1995. Aftermath of the Permian-Triassic mass extinction event: Paleoecology of Lower Triassic carbonates in the western USA. Palaeogeography, Palaeoclimatology, Palaeoecology 116:1-39 [D. Bottjer/N. Bonuso/N. Bonuso]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 32975: authorized by David Bottjer, entered by Nicole Bonuso on 21.07.2003

Creative Commons license: CC BY (attribution)

Taxonomic list

 Cidaroida - Miocidaridae
Miocidaris sp. Döderlein 1887 pencil urchin
 Holocrinida - Holocrinidae
Holocrinus sp. Wachsmuth and Springer 1886 Sea lily
 Cardiida - Kalenteridae
Permophorus sp. Chavan 1954 clam
 Cardiida - Anthracosiidae
Unionites sp. Wissman 1841 clam
 Trigoniida -
Trigoniacea indet. Lamarck 1819 clam
 Myalinida - Myalinidae
Promyalina sp. Kittl 1903 clam
 Pectinida - Aviculopectinidae
Eumorphotis sp. Bittner 1901 scallop
 Pectinida - Hunanopectinidae
Leptochondria sp. Bittner 1891 scallop