Palynofacies as indicators of paleoenvironmental changes in a Cretaceous succession from the Larsen Basin, James Ross Island, Antarctica

• We examine the stratigraphic distribution of palynofacies of the Larsen Basin.
• The four revealed palynofacies shows a long-term regression trend.
• From base to top, the sequence is a slope-apron, a fan delta and a marine-shelf.

In order to reconstruct the paleoenvironment of one of the most extensive marine Cretaceous successions in the Southern Hemisphere, palynofacies analyses were conducted on 83 samples from the Whisky Bay (Albian–Turonian), Hidden Lake (Coniacian) and Santa Marta (Santonian–Campanian) formations in the Larsen Basin, James Ross Island, Antarctica. Categories of particulate organic matter were counted and investigated by cluster analysis. The trends and parameters of palynofacies constituents were used to reconstruction paleoenvironments based on the existing sedimentological interpretation. The stratigraphic distribution of the four identified palynofacies associations (A–D) reflects a continuous terrestrial influx throughout the succession. From base to top, a conspicuous increase in woody elements, especially non-opaque particles, is observed. This increase in continental elements occurs despite the presence of marine elements. This finding corroborates the sedimentological interpretation of a deeper water paleoenvironment during deposition of the Whisky Bay Formation and initiation of a shallowing-upward trend in the Hidden Lake Formation, culminating with shallow marine shelf environment of the Santa Marta Formation.