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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 66 (1982)

Issue: 5. (May)

First Page: 585

Last Page: 585

Title: Development and Hydrocarbon Potential, Carbonate Platforms Offshore Northeastern America: ABSTRACT

Author(s): Lubomir F. Jansa

Article Type: Meeting abstract

Abstract:

The Jurassic-Lower Cretaceous carbonate platforms and banks form a discontinuous belt extending from the Grand Banks to the Bahamas (over 6,000 km). The thickness of the carbonate buildups progressively increases southward along the margin, attaining a thickness of more than 5 km on the Bahamas. The platforms also become younger southward, which has been interpreted as an indication of a northward motion of the North American plate. Six types of carbonate buildups recognized document variability of depositional, paleo-oceanographic, and tectonic processes along the margin. The composition of the buildups closely resembles the recent deposits of the western Great Bahama Bank, since oolitic shoals were present near the shelf edge and skeletal, peloid wackestones and biomicr tes were deposited in the inner part of the platform. Coral-hydrozoan, sponge and algal stromatolite bioherms and reefs are important constituents of the Late Jurassic-Early Cretaceous shelf edge. The hydrocarbon prospectivity of the carbonate front differs for the individual carbonate platform types which prevents construction of a single model for evaluation of their hydrocarbon potential. Porosity has locally developed as a result of secondary dolomitization in a mixing zone. Hydrocarbons were at least locally generated and migrated through the porous carbonate rocks. The major critical factor is presence of a rich source rock. The latest deep sea drilling on the northwestern African and eastern North American margins, together with the interpretation of the Mesozoic paleogeography of the shelf, allows the elucidation of this important factor in a time and space framework of margin development.

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Copyright 1997 American Association of Petroleum Geologists