Sedimentology and stratigraphy of the Falkland Islands Permian with comparisons to Gondwanan stratigraphy of South Africa and South America
The Falkland Islands, located in the SW of the South Atlantic Ocean form the only emergent part of a large continental shelf area, the Falkland Plateau. It has long been known since the work of Adie (1952a,b) that the predominantly Devonian and Permian aged onshore strata probably form the missing SE quadrant of the Karoo Basin of South Africa. Until recently relatively little work has been implemented to confirm this beyond doubt. This study provides additional evidence for such origins through comprehensive sedimentological analysis of onshore Permian exposure in the Falkland Islands with a view to providing a robust stratigraphical framework based on sedimentological data, ichnofacies and petrography. Extensive Falkland Islands fieldwork was complemented by similar work in the Sierras Australes, Buenos Aires Province, Argentina, and in Ecca Pass in South Africa to enable comparisons of the Permian stratigraphy. The Falkland Islands stratigraphic succession represents a post-glacial basin-filling episode representing a passage from a deep underfilled to a filled basin. Deposition occurred within a foreland basin. The results indicate a close correlation between the sedimentology and stratigraphy of South Africa and the Falkland Islands, between which stratigraphic units may be correlated at a member level. The Falkland Islands and South African successions are closely comparable in terms of petrographic trends implying a similar provenance. Strata of the Sierras Australes are sedimentologically and petrographically distinct and deposition of the basin-filling succession at this location commenced at an earlier date. Palaeocurrent orientations between the Falklands Islands and the Sierras Australes succession do not compare well, whilst Falkland Islands palaeocurrent orientations only compare with South African examples if the Falkland Islands are rotated by approximately 180° relative to their present orientation.