Description
Predominantly conglomerate with thin persistent sandstone interbeds, exposed on eastern Coronation Island and Matthews Island, deposited as debris flows and braided stream deposits in alluvial fans within terrestrial to marine fault-bounded basins. Boulders lithologically resembling the Scotia Metamorphic Complex (2) are dominant and suggest a local derivation from the west. Age constraints come from calcareous sandstone boulders at Rayner Point which contain a Late Jurassic - Early Cretaceous fauna and also from a poorly preserved Late Jurassic marine fauna on Matthews Island. Basal units in the vicinity of Gibbon Bay, eastern Coronation Island, consist of sparsely fossiliferous (Late Jurassic - Early Cretaceous) dark marine shale, the Gibbon Bay Shale. It rests unconformably on the Scotia Metamorphic Complex (1).
Age
Late Jurassic - Early Cretaceous
Map Reference
Flowerdew, M. J. & Haselwimmer, C. E. Geological Map of the South Orkney Islands (1:150 000 scale). Sheet 2, (British Antarctic Survey, 2011). Available here.