Abstract: Geology and Petroleum Potential of Central America

A. E. L. Morris

In the landmass and adjacent offshore between 98°W long. and the eastern border of Panama there are five principal tectonic-stratigraphic provinces: (1) the Yucatan platform, an early Paleozoic and Precambrian massif; (2) the Northern Central American orogene, a geosynclinal foldbelt containing rocks that range in age from Proterozoic to late Tertiary; (3) the stable platform or semiplatform area of Nuclear Central America (Central American geanticline); (4) the late Jurassic and younger Southern Central American orogene; and (5) the Cenozoic San Andres-Providencia volcanic "arc" east of the Caribbean Nicaragua shelf.

Twenty sedimentary basins are present within this framework, the most important of which are on the fringe of the Yucatan platform and in the Northern Central American orogene. These basins have an aggregate sedimentary volume of 5.0 million cu km, 75% of which occupies the offshore and onshore basins of southern Mexico and northern Guatemala.

The granite-intruded metamorphic basement of the Yucatan platform is overlain by a thin red-bed sequence followed by up to 4,000 m of Cretaceous and Tertiary predominantly evaporites and carbonate rocks. Metamorphosed sediments of the Northern Central American orogene are late Proterozoic and early Paleozoic in age. Unmetamorphosed strata, ranging from Pennsylvanian to Tertiary, are more than 12 km thick in the deepest basins. Predominantly carbonate sequences of late Paleozoic and Late Jurassic-Cretaceous ages are separated by a continental section of early-middle Mesozoic age; Tertiary sediments are clastic. Sediments of the Central American platform are generally exposed and markedly deformed; those of the Southern Central American orogene, which are Cretaceous and younger in age, re largely clastic and commonly volcanogenic.

Southern Mexico has produced oil since 1904 and recent discoveries have established it as having the largest concentration of proved reserves in the Western Hemisphere. This same area has the greatest potential for additional discoveries. In order of decreasing importance, other regions with petroleum potential are the Chapayal basin of north-central Guatemala, offshore basins of the Nicaragua Rise, the Limon-Bocas del Toro which straddles the north coast of Costa Rica and Panama, and the Darien basin in eastern Panama.

AAPG Search and Discovery Article #90962©1978 AAPG 2nd Circum-Pacific Energy and Minerals Resource Conference, Honolulu, Hawaii