Geology of the North Falkland Basin

The North Falkland Basin comprises two main structural elements: a north-south trending graben, termed the North Falkland Graben; and a set of subsidiary basins to the west of this graben, also controlled by north-south trending extensional faults, but which have been constrained by NW-SE oriented, reactivated Palaeozoic thrust faults. The North Falkland Graben can be divided, in its northern part, into western and eastern depocentres, which are separated by a north-south trending intra-graben high. Early syn-rift, late syn-rift, early post-rift and late past-rift successions have been identified within the North Falkland Graben. The subsidiary grabens to the west probably contain only early syn-rift deposits overlain by bate post-rift sediments: these basins were possibly uplifted along the shoulder of the main graben during its main phase of extension in the Late Jurassic to Early Cretaceous. Although predictions of sediment-infill type have only been made by regional correlations and seismic facies analysis in these undrilled basins, two major deltaic units of early post-rift age are confidently inferred to be present in the North Falkland Graben, and to pass laterally into possible anaerobic mudstones of source-rock quality. This petroleum system will soon be tested by a number of oil companies sharing production licences for the entire axial area of the North Falkland Graben.