A reconstruction of the early Palaeocene palaeovegetation of Turtle Mountain, south-western Manitoba, Canada

Abstract

The lower Goodlands Member of the Turtle Mountain Formation is exposed in a streambank outcrop on the western flank of Turtle Mountain, south-western Manitoba, Canada (49°0′2″N, 100°14′51″W). This outcrop was sampled for a 1.5 m section of microfossil-rich non-marine clay and coal-rich sediments deposited in a coastal plain environment during the early Palaeocene. These sediments were deposited 65.4–65 Ma and thus offer an opportunity to reconstruct terrestrial palaeoecology 0.6 to 1 Ma after the Cretaceous–Paleogene boundary (K–Pg) extinction event. We use quantitative palynology to reconstruct terrestrial plant ecology and explore ecological patterns of recovery and succession of these communities on a millennial time scale. Quantitative palynological analyses shows that at the time of deposition of the Goodlands Member the landscape on the coastal plain of the Western Interior Seaway – in what is now south-western Manitoba – was covered in a forested canopied swamp with tall standing swamp cypress and other conifers, Juglandaceae (walnut family), birch, alder, elms and other angiosperms, with an understory of ferns and ground cover of Sphagnum moss. Notably, palms were present but scarce, indicating a relatively warm climate. No successional pattern of diversity and community composition is evident in the samples; all samples showed high plant diversity (33–54 taxa/sample, H′ 2–3). Vegetation in Manitoba recovered within 0.6 to 1 Ma following the K–Pg extinction event or was predominantly influenced by local environmental patterns independent of time.

Keywords:

• Palaeocene
• Canada
• coal
• palaeoecology
• K–Pg
• Turtle Mountain Formation

Acknowledgements

This research arose out of undergraduate theses by Nidhi Patel and Mackenzie Desautels, at Brandon University. We thank Jim Bamburak (formerly of the Manitoba Geological Survey) and the late Arthur Sweet (formerly of the Geological Survey of Canada, Calgary) for their advice. We acknowledge the contributions towards sampling of the short section by the 2007 palaeobotany undergraduate class at Brandon University. We also thank K. Dewing (GSC Calgary) for editorial suggestions. This article represents NRCan contribution number/Numéro de contribution de RNCan: 20210401.

Data availability statement

The data that support the findings of this study are provided in a supplementary file.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

David R. Greenwood thanks the Natural Sciences and Engineering Research Council of Canada (NSERC) for funding from a Discovery Grant (RGPIN 2016-04337) and the Brandon University Research Committee (for grant 2005-2724).