The stratigraphic position and the age of the Ordovician organic-rich intervals in the northern Hudson Bay, Hudson Strait and Foxe basins – evidence from graptolites.

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Zhang, Shunxin, Riva, John F. V.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Ordovician organic-rich intervals; graptolites; northern Hudson Bay Basin; Foxe Basin; Hudson Strait Basin; Hudson Bay; Baffin Island; Hudson; Hudson Strait; Southampton Island; Akpatok Island; Amadjuak; Red Head Rapids; Boas River; Baffin; Foster Bay
• Online Access: https://espace.inrs.ca/id/eprint/6897/; https://espace.inrs.ca/id/eprint/6897/1/P3309.pdf; https://doi.org/10.1139/cjes-2017-0266

Graptolites recovered from the organic-rich intervals, previously named the Boas River Formation in the Upper Ordovician succession on Southampton, Akpatok and southern Baffin islands provide a reliable age assessment for the Upper Ordovician petroleum source rocks in the northern Hudson Bay, Hudson Strait and Foxe basins. They are characterised by Anticostia lata and An. hudsoni in the lower Red Head Rapids Formation on Southampton Island; An. decipiens and Rectograptus socialis in the lower Foster Bay Formation on Akpatok Island; and Diplacanthograptus spiniferus and Amplexograptus praetypicalis in the lower Amadjuak Formation on southern Baffin Island. These data suggest that the organic-rich intervals in the northern Hudson Bay and Hudson Strait basins can be correlated to the Dicellograptus anceps and Paraorthograptus pacificus zones of the upper Katian, and the horizon in the Foxe Basin to the Diplacanthograptus spiniferus Zone of the lower Katian. The Boas River Formation is not deemed appropriate to use as it occurs as an organic-rich interbed in different stratigraphic units in different basins; therefore, it is suggested to abandon it as a stratigraphic term.