To obtain a global view of climate change, the climatic and evolutionary history of the Southern Hemisphere needs to be integrated into the picture, and an integration of high-latitude change is particularly important. To assist this integration, we applied the methods of palynology and Sr isotope stratigraphy to confirm and refine the numerical ages of the sedimentary succession within the Antarctic Peninsula. We were able to establish a precise chronology using strontium isotope stratigraphy. Various calcitic and aragonitic fossil shells collected from these strata proved to be exceptionally well preserved and strontium isotope ratios obtained from them have provided some of the most accurate ages yet obtained for Cretaceous sedimentary rocks in the Southern Hemisphere. Revision of the age of the succession dramatically changed the accepted ages, by half a Stage, from Barremian-to-Santonian to Aptian-to-Coniacian.

To provide further stratigraphic resolution through the Gustav Group a key section through the Kotick Point, Whisky Bay and Hidden Lake formations, adjacent to Brandy Bay on northern James Ross Island was re-measured and sampled for both Sr isotope stratigraphy and palynostratigraphy. In total, a sedimentary succession about 1600m thick, that encompasses the initial three stages of the Upper Cretaceous period, was measured and a suite of invertebrate macrofossils, palynology samples, palaeobotanical and general lithological samples were collected along the lines of measured samples.