Journal of Petroleum Geology, Vol.16,
No.4, pp. 451-464, 1993
©Copyright 2000 Scientific Press,
Ltd.
BASIN EVOLUTION AND
PROSPECTIVITY OF THE ARGENTINE CONTINENTAL MARGIN
M. L. Keeley* and M. P. R. Light*
* Intera Information Technologies,
Highlands Farm, Greys Road, Henley-on-Thames, Oxfordshire RG9
4PS.
Abstract
Nine Mesozoic-Tertiary basins of different
orientations lie along the Argentine continental margin, over a
distance exceeding 2,000 km: these are the Salado, Colorado,
Valdes Rawson, San Jorge offshore, North Malvinas (San Julian),
West Malvinas and Magallanes (Austral) Basins on the Continental
Shelf: together with the Continental Slope. These basins formed
following the latest Jurassic-Early Cretaceous extension that
accompanied the onset of South Atlantic rifting. Strain was
modified by earlier basement fabrics with consequent
transtension. The Cape Fold Belt (Permo-Triassic) provided a
NW-SE grain to pre-Mesozoic cover off NE Argentina. In the
central-southern sector, several phases of oblique NEwards
Pacific subduction and terrane accretion during the
Permo-Triassic, formed back-arc basins and volcanic belts
producing a more variable fabric orientated close to NNW-SSE.
Atlantic basin fill, of Lower Cretaceous-Tertiary clastics, was
deposited as a result of rift-shoulder erosion and Atlantic
flooding, following eastward tilting. Basin fill thickness is
typically 2-4 km, but locally exceeds 6km. The hydrocarbon
potential of these basins hinges as much upon the preservation of
source rocks within the pre-rift succession as it does on that of
those within the base-rift succession, and sub sequent Atlantic
anoxic events.
