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 post‐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 late post‐rift sediments: these basins were possibly uplifted along the shoulder of the main graben during its mainphase 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.