Abstract: Tectonostratigraphic Evolution and Petroleum Systems of the Barinas-Apure Basin and Surrounding Areas

N. Chigne, D. Loureiro, E. Cabrera, S. Osuna

Nine megasequences have been recognized and related to major basin forming processes: (1) 202-142 m. y.: first rifting event; (2) 128-111 m. y.: second rifting event; (3) 111-75 m. y.: thermal subsidence; (4) 75-65 m.y.: transition from thermal to flexural subsidence; (5) 65-50 m. y.: flexural subsidence in the southwest related to the final accretion of the Western Cordillera of Colombia; (6) 50-39 m. y.: flexural subsidence in the north-northwest associated to the emplacement of the Lara nappes; (7) 39-15 m. y.: two megasequences, separated by a Middle Miocene unconformity, deposited in a flexural setting resulting from thrusting and uplift in the Western and Central Cordilleras of Colombia and the Perija range; (8) 15-0 m. y.: latest phase of foreland development resul ing from inversion and uplift along the Merida Andes. The well known Cenomanan-Turonian source rock is involved in most of the mountain building process.

Thermal modelling suggests at least two major events of oil generation and migration. The first one took place between late Middle Eocene and Oligocene, coeval to the emplacement of the Lara nappes. A second pulse started during the Miocene, as a result of thrusting and uplift of the Merida Andes.

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