The occurrence of Mesozoic oceanic floor and ancient continental crust on South Georgia

The Larsen Harbour Formation of southern South Georgia is part of an ophiolite sequence of submarine lavas and sheeted dykes emplaced into metasedimentary country rocks. The metasediments are remnants of a pre-Cretaceous continental crust which had been subject to regional metamorphism and polyphase deformation prior to intrusion by a variety of acid and basic igneous rocks (roots of the ophiolitic sequence). It is proposed that the segment of continental crust and the Larsen Harbour Formation formed the floor of a back-arc basin which was infilled during Early Cretaceous time by a thick sequence of volcaniclastic sediments (Cumberland Bay Formation).