Sedimentology, palynology and structure of Humps Island, northern Antarctic Peninsula

Approximately 200 m of sediments assigned to the Late Creaceous Lopez de Bertodano Formation are exposed on Humps Island, northern Antarctic Peninsula. The facies present represent deposition from density currents, sedimentation from suspension or dilute density currents, followed by post-depositional reworking by bioturbation and sedimentation from suspension of primary air-fall ashes. These represent out shelf deposition below storm wave base. The palynofloras of all samples taken were dominated by dinoflagellate cysts, with smaller proportions of land-derived spores and pollen, indicative of a Late Campanian to Early Maastrichtian age. Localized displacement and tilting on faults has resulted in considerable variation in dip direction. Normal and reverse faults, possibly synsedimentary, are also present. This faulting may be related to strike-slip deformation and basin uplift during the Late Cretaceous. Vitrinite reflectivity data from both James Ross Island and Seymour Island also suggests basin uplift, and can be related to a regression and associated eastward progradation of the coastline during the Late Cretaceous.