Geological exploration of South Atlantic islands and its contributions to the continental drift debate of the early 20th century

The geological character of the South Atlantic islands was only slowly established during the first half of the 20th century. That same period was marked by a generally dismissive view of continental drift but, as the continental nature of the islands became apparent, their ‘oceanic’ setting was utilised by both sides of the ‘drift’ debate to support their respective positions. So islands such as the Falklands archipelago and South Georgia were cited either as fragments detached from larger continental bodies during drift, or as the last surviving vestiges of a huge continental landmass that had subsided beneath the water of the South Atlantic. The appreciation of the Scotia Arc as a dynamic geological construct arising from lateral tectonics, and the Falkland Islands as representative of an itinerant continental fragment, were features of some early accounts of the region, but such ideas were generally discounted by the geological establishment of the day. This paper reviews the early, pioneering contributions to the geological understanding of the Falkland Islands, South Georgia and the Scotia Arc region, assessing their contemporary reception and tracing their influence on the developing continental drift controversy. Though commonly dismissed or ignored at the time, many of the ‘pro-drift’ ideas expressed were subsequently rediscovered by proponents of plate tectonics as that revolution swept through geology in the late 1960s.