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

Abstract

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.