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Petroleum Geology of Falkland Islands Region, Including Malvinas Basin

James W. Clarke, Charles D. Masters

The Falkland Islands are on continental crust that is part of the South American lithospheric plate. Two prospective areas for oil and gas are Malvinas basin south of the Falklands extending onto Burdwood Bank, and Falkland Plateau east and northeast of the Falklands.

To evaluate this area, workers must understand the paleogeography at the time the Atlantic Ocean opened, during the Jurassic and Cretaceous, because this environment controlled deposition of euxinic muds, which are the prime source beds for oil and gas. Thick Upper Jurassic source beds have been penetrated by the drill on the Falkland Plateau and in the Magallanes basin. The seismic profiles across the Malvinas basin, Burdwood Bank, and Falkland Plateau suggest that the Jurassic-Cretaceous source beds may be continuous throughout the entire area. Now the question is, does the euxinic claystone facies extend throughout the same area? This question remains, as do those concerning traps, seals, and structures. We surmise that block faulting will have disturbed the sedimentary pile suffic ently for traps to have formed.

In the eastern part of Malvinas basin, which includes Burdwood Bank, the thick (up to 7,000 m) sedimentary section is favorable for hydrocarbon accumulations. However, the lower part of this section may have generated gas, which in turn may have displaced most of the trapped oil.

AAPG Search and Discovery Article #91043©1986 AAPG Annual Convention, Atlanta, Georgia, June 15-18, 1986.