GSC 84342, Lac des Bois (1968 collection) (Cretaceous of Canada)

Where: Northwest Territories, Canada (66.9° N, 125.4° W: paleocoordinates 71.1° N, 69.1° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Early/Lower Turonian (93.5 - 89.3 Ma)

• By tracing the dipping slope of the sediments, the field party was able to determine the relative position of the cliff outcrop and the beach shales; the two form a continuous unit, with the shoreline shales being only a few centimeters below the concretion layer. Based on the macroinvertebrate fauna, primarily ammonites and inoceramid pelecypods, the shales and concretions are early Turonian in age (Jeletzky, 1969, report in Cook and Aitken, 1971; Yorath and Cook, 1981; Cumbaa and Murray, 2008), and were deposited in an open marine environment during a transgressive sequence that was initiated in the Albian (Yorath and Cook, 1981; Cumbaa and Murray, 2008).

• group of beds-level stratigraphic resolution

Environment/lithology: offshore; lithified sandstone and siltstone

• The environment at Lac des Bois during the early Turonian was open marine (Yorath and Cook, 1981), with the probability of widespread and persistent bottom layer anoxia (Schroder-Adams et al., 1996). Sea level at the time was near highstand, with waters at maximum depth in the Western Interior Seaway, and depth at the locality was likely in the tens of meters or greater (Cumbaa and Murray, 2008).
• Dr. C. J. Yorath (personal communication to Dr. D. A. Russell, 1968) stated: "The specimen was found within concretionary sand-stones of what we have been calling the 'Basal Cretaceous sandstone'. This unit covers a wide area and unconformably overlies beds of Devonian and OrdovicianSilurian age. The sand-stones are normally clean, well-sorted, rather poorly consolidated and frequently cross-bedded. Minor conglomerates occur locally. These sandstones are probably equivalent at least in part to the thick sandstones and coal sequence on the Horton River. Associated with the specimen were a number of internal casts of large pelecypods and other material of marine affinity."

Size class: macrofossils

Collected by A geologist working for V. Zay Smith Associates of Calgary in 1968

Primary reference: M. Waldman. 1969. Ichthyodectes and Holcolepis from the Cretaceous of Lac des Bois, Northwest Territories, Canada. Canadian Journal of Earth Sciences 6:1316-1319 [M. Clapham/J. Mordaunt]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 220897: authorized by Matthew Clapham, entered by Josh Mordaunt on 24.06.2021

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Actinopteri
 Elopiformes - Osmeroididae
"Holcolepis sp." = Osmeroides
"Holcolepis sp." = Osmeroides Agassiz 1835
 Ichthyodectiformes - Ichthyodectidae
Ichthyodectes ctenodon