Late Carboniferous Tropical Dryland Vegetation in an Alluvial-plain Setting, Joggins, Nova Scotia, Canada

Abstract

Abstract The composition and ecology of Late Carboniferous tropical, dryland plant communities are described for the first time. The study focuses on a 700-m-thick succession through the Langsettian Joggins Formation. Red bed units (5–110 m thick) bearing isolated pedogenic carbonate nodules occur at fourteen intervals and are interpreted as originating in a seasonally dry, well-drained, alluvial-plain setting characterized, in places, by an anastomosing fluvial geometry. A quantitative quadrat analysis of red bed floral assemblages preserved as compressions, impressions, calcareous permineralizations, and charcoal was undertaken. Cordaites, represented by woody trunks, branches, pith casts, leaves, and seeds, comprise 74% of the red bed floral thanatomass, together with minor pteridosperms and sphenopsids, and rare sigillarian lycopsids. Taphonomic data demonstrate that while fire-prone cordaite-pteridosperm vegetation dominated nearly all seasonally dry floodplain niches, hydrophilic lycopsids and sphen...