Section AV1 077.5 m, Whittaker Fm., Avalanche Lake Area, Mackenzie Mts. (Ordovician of Canada)

Where: Northwest Territories, Canada (62.4° N, 127.0° W: paleocoordinates 9.1° N, 55.4° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Normalograptus persculptus zone, Whittaker Formation, Hirnantian (445.2 - 443.4 Ma)

• bed-level stratigraphic resolution

Environment/lithology: open shallow subtidal; argillaceous limestone and calcareous shale

• For entire Whittaker/Road River/Delorme suite: "The sediments were deposited in an area adjacent to the boundary between the Paleozoic continental shelf (Mackenzie shelf/platform) and the slope into the marginal Selwyn Basin."

•

•SEP environmental call based primarily on PBDB ref. 7215. IF age assignment is correct, then this unit is consistent with the last portion of the HST in the upper-most Ord. and immediately prior to TST of lowermost-Sil. and latest Ord. Shallow assignment based on Bathyurus in ref. 7215.

• For entire Whittaker/Road River/Delorme suite: "The sediments are predominantly carbonates with varying amounts of argillaceous material, ranging from fairly pure limestones, through argillaceous limestones and calcareous shales, to almost pure siliciclastic shales with some intervals containing minor to major amounts of chert."

Size classes: macrofossils, mesofossils

Preservation: replaced with silica

Primary reference: J. Jin and B. D. E. Chatterton. 1997. Latest Ordovician-Silurian articulate brachiopods and biostratigraphy of the Avalanche Lake area, southwestern District of Mackenzie, Canada. Palaeontographica Canadiana 13:1-62 [M. Foote/M. Foote/M. Foote]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 26070: authorized by Michael Foote, entered by Michael Foote on 02.10.2002, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

• Articulate brachiopods only.
Show authors, comments, and common names
Strophomenata
 Strophomenida - Furcitellidae
Katastrophomena mackenzii
Katastrophomena mackenzii Jin and Harper 2024
31 vv, 41 dv
Rhynchonellata
 Pentamerida - Virgianidae
Brevilamnulella laevis
Brevilamnulella laevis Sapelnikov and Rukavishnikova 1975
1 sh, 2 vv, 1 dv
 Atrypida - Atrypinidae
Eospirigerina putilla, Eospirigerina putilla
Eospirigerina putilla Hall and Clarke 1894
9 sh
Eospirigerina putilla Hall and Clarke 1894
3 sh
 Orthida - Dicoelosiidae
Epitomyonia sekwiensis
Epitomyonia sekwiensis Lenz 1977
4 sh, 10 vv
 Orthida - Dalmanellidae
Dalmanella edgewoodensis
Dalmanella edgewoodensis Savage 1913
16 vv, 11 dv
 Orthida - Platystrophiidae
Gnamptorhynchos orbiculoidea
Gnamptorhynchos orbiculoidea Jin and Chatterton 1997
5 sh, 27 vv/dv
 Protorthida - Skenidiidae
Skenidioides sp.
Skenidioides sp. Schuchert and Cooper 1931
2 vv