Western Prince of Wales Island, Section 8, Unit 4, GSC loc. C26880 (Devonian of Canada)

Also known as Plicogypa-Atrypa Community

Where: Nunavut, Canada (73.5° N, 100.0° W: paleocoordinates 2.2° S, 30.2° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Lochkovian (419.2 - 410.8 Ma)

• Unnamed formation. "The age of this section is in part, at least, late Lochkovian." Brachipods correlative with Quadrithyris Zone. Conodont fauna 3 of Klapper.

• bed-level stratigraphic resolution

Environment/lithology: lagoonal or restricted shallow subtidal; gray, argillaceous, silty lime mudstone

• Deposits in this region are of two general kinds: shallow-water stable carbonate platform (generally in the NW part of Arctic Archipelago) and deeper basinal facies (generally to the SE). This collection is in the former. This is in Smith's Plicogypa-Atrypa Community. "Common notable additional memebers of the fauna are fish, gastropods, and pelecypods. Rare constituents are ostracodes and solitary corals...Notable here is the absence of echinoderm fragments, colonial corals, calcareous algae, or bryozoa which are generally associated with brachiopods of this type. The community is found in very highly argillaceous silty, thin-bedded lime-mudstone. It thrived in a quiet, possibly pretected-water environment as shown by the lack of organisms commonly associated with the normal marine fauans. Most of the brachiopod taxa are of the type that did not possess a functional pedicle and presumably lived unattached on the soft muds of the sea bottom." "This complex section represents a broad shallowing-trend with minor reversals from its basal beds which were deposited in a quiet-water, subtidal environemnt. The topmost beds were deposited in a high energy, shallow environment, as indicated by the presence of fragments of colonial corals and stromatoporoids."

•SEP environmental call based on given info and regional context

• Section in general: "Section 8 contains varied and complex lithologies. The basal beds are highly argillaceous, thin bedded, fossiliferous lime mudstone. These exhibit channeling within thin to med. bedded, well cemmented calcareous siltstones which contain angular quartz. The siltstones are devoid of megafauna except for a few beds that contain fare diarticulated brachiopods and poorly preserved fish remains. These channels may have been formed on shallow-subtidal areas. Higher upsection, these two units are interbedded in places, and in others the argillaceous lime-mudstone units are channel infillings within the...siltstone...etc. etc." This unit: "Lime mudstone: thin to med. bedded, fairly lenticular; med. grey...well indurated, quite silty, rare brachiopods, few argillaceous seams, rare poorly preserved fish at base"

Reposited in the GSC

• Smith gives specimen counts.

Primary reference: R. E. Smith. 1980. Lower Devonian (Lochkovian) biostratigraphy and brachiopod faunas, Canadian arctic islands. Geological Survey of Canada Bulletin 308:1-155 [M. Foote/M. Foote/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 26491: authorized by Michael Foote, entered by Michael Foote on 16.10.2002

Creative Commons license: CC BY (attribution)

Taxonomic list

• Focus of the entire monograph is on brachiopods. Other taxa mentioned but not necessarily listed in detail.
Rhynchonellata
 Rhynchonellida - Machaerariidae
Machaeraria obesa n. sp. Smith 1980
 Pentamerida - Gypidulidae
 Orthida - Schizophoriidae
Schizophoria sp. King 1850
 Atrypida - Atrypidae
Atrypa sp. Dalman 1828