Middle Jurassic to Lower Cretaceous paleoclimate of Sverdrup Basin, Canadian Arctic Archipelago inferred from the palynostratigraphy

Jurassic to Cretaceous strata of Sverdrup Basin contain both marine and nonmarine fossils that serve to date interlayered sandstone and mudstone units and interpret paleoenvironments and paleoclimates. Applying a multi-variate statistical approach to long-ranging spore and pollen types typical for this time interval, we define four palynoassemblages within an Aalenian to Albian succession preserved in the Hoodoo Dome H-37 oil and gas well located on southern Ellef Ringnes Island near the centre of Sverdrup Basin. We propose an association between palynoassemblages and Middle Jurassic to Early Cretaceous pan-hemispherical climate events. The largest palynoassemblage shift occurs when an assemblage containing Classopollis classoides pollen is replaced by an assemblage dominated by pollen of the Taxodiaceae–Cupressaceae–Taxaceae in the late Valanginian or early Hauterivian. We interpret this vegetation change to a shift from a seasonally arid climate to cooler and more humid conditions in high latitude regions.

► Palynoassemblages (Aalenian–Albian) changes in Arctic are linked to climate.
► The largest palynological shift occurs in the late Valanginian/early Hauterivian.
► Vegetation change occurred at this time due to development of more humid climate.