Journal of Petroleum Geology, Vol.14, No.3, pp. 323-342, 1991
©Copyright 2000 Scientific Press, Ltd.
GEOLOGIC AND HYDROCARBON EVOLUTION OF BARBADOS
R. C. Speed*, L. H. Barker** and P. L. B. Payne +
* Dept. Geological Science, Northwestern University,
Evanston, IL, USA, 60208.
**Energy Unit, Ministry of Finance, Wildey, Barbados
+ Barbados National Oil Co., St. Philip, Barbados.
Abstract
Barbados Island has risen above sea-level in the last one million
years as a pinnacle on the structural high of the extensive Barbados accretionary prism.
The island provides by outcrop and many wells a glimpse of the structural history of the
oldest and thickest realm of the prism, and a model for evolution of oil and gas in an
accretionary terrane rich in quartz sandstones and muddy terrigenous and hemipelagic rocks
that are moderately rich in organic substances. The island contains four major
tectonostratigraphic units: basal complex of Eocene accretionary origin, prism cover; the
Oceanic allochthon, of marly forearc basin strata, that was thrust over the basal complex
and prism cover, and mud-matrix melange diapirs. Oil and gas are sourced chiefly from the
basal complex at depths below 7 km, the minimum maturation depth. Oil reservoirs are in
sandstones of the basal complex in fault-fold structures. Seals are provided by mudstones
of the basal complex and, more regionally, by thick, impermeable successions of prism
cover and the Oceanic allochthon. Current oil reservoirs probably evolved mainly in Late
Neogene time during a late stage of deformations. Oil reservoirs are best known in
southern Barbados, in the Woodbourne Trough, where sealing conditions were optimized
