Abstract: The Overthrusted Zaza Terrane of Middle Cretaceous Over the North American Continental Carbonate Rocks of Upper Jurassic-Lower Cretaceous Age--Relationships to Oil Generation

Gustavo Echevarria Rodriguez, Jose Alvarez Castro, Silvia Valladares Amaro

The Zaza Terrane is part of the Caribbean plate thrust over the southern edge of the North American basinal and platform carbonate rocks of upper Jurassic-Lower Cretaceous age. Zaza Terrane are volcanic and ophiolitic rocks of Cretaceous age. The ophiolites are mostly serpentines which behave as reservoirs and seals. All Cuban oil fields are either within Zaza Terrane or basinal carbonates underneath, or not far away to the north of the thrust contacts. It appears that the overthrusting of the Zaza Terrane caused the generation of oil in the basinal carbonate source rocks underneath, due to the increase of rock thickness which lowered the oil window to a deeper position and increased the geothermal gradient. Oil generation was after thrusting, during post-orogenic.

API gravity of oil is light toward the south and heavy to very heavy to the north.

Source rocks to the south are probably of terrigenous origin.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela