干旱区生态环境知识资源中心

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. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.