Chapter 7: The Antarctic Continent in Gondwanaland: A Tectonic Review and Potential Research Targets for Future Investigations

The geological record of the Antarctic continent has, for a long time, had a key role in supercontinent reconstructions. More recently, because of the well-documented relevance of the polar regions' processes in influencing the global changes of both ocean circulation and climate patterns, Antarctica has increasingly been of similar importance in the context of palaeoenvironmental and palaeoclimatic investigations, particularly those focused on the Cenozoic glacial evolution. After a description of the present-day geotectonic setting and of the main geological units before Gondwana amalgamation, the chapter focuses on the tectonic evolution of the Antarctic continent from its inclusion as part of the Gondwana supercontinent to the break-up of this landmass and the repositioning of Antarctica at southern polar latitudes since the Early Cretaceous. The geological evolution of the Antarctic continent is reviewed considering two main time periods: (i) c. 600-450 Ma, covering the processes which were active immediately before and during the amalgamation of Gondwana; and (ii) c. 450-180 Ma, including all the major events that occurred after the final stage of Gondwana amalgamation to the time immediately before the break-up phase. A subsequent section addresses the last 180 Ma during which present-day Antarctica and the other southern continents and surrounding oceanic basins formed as a consequence of the fragmentation of Gondwana. After a general overview of the most significant plate tectonic stages and coeval magmatic products, the attention is then devoted to one of the most investigated regions in Antarctica; the Transantarctic Mountains and the Ross Sea sector of the Western Antarctic Rift System. Some of the main persisting problems and potential research themes for on- and off-shore activities are discussed in the conclusions, which also include some of the most interesting palaeoclimatic issues that are essential to improving our understanding of the polar climate, ice ages and their influences on Earth's climate system in the Cenozoic to present time.