Caribbean Basin Framework, 4: Maracaibo Basin, Northwestern Venezuela

LUGO, JAIRO, University of Texas at Austin, Austin, TX

The Maracaibo basin is presently located in a topographic depression on the Maracaibo block, a a triangular, fault-bounded block within the Caribbean-South America plate boundary of northwestern Venezuela. Intense oil exploration over the last 50 years has produced a large amount of seismic and well data that can be used to constrain four Jurassic to Recent tectonic and depositional events that affected the region:1. Late Jurassic rift phase and subsidence along normal faults striking north-northeast across the floor of the basin; subsidence is attributed to separation of northwestern South America from southern North America.2. Cretaceous to early Eocene subsidence recorded by shallow to deep marine carbonate and clastic rocks that thicken from south to north and completely cover Per ian rocks of the Merida arch; subsidence is attributed to thermal subsidence of the South American rifted margin.3. Eocene folding, thrusting, and initial reactivation of Jurassic normal faults as convergent strike-slip and reverse faults. Eocene clastic sediments are thickest in a narrow northwest-trending foredeep on the northeastern margin of the basin; clinoforms document southwestward progradation into the foredeep; formation of the

foredeep and southwestward progradation of sediments is attributed to accretion of island arc terranes to the rifted margin of northern South America.4. Late Miocene to Recent northwest-southeast convergence is marked by continued reactivation of Jurassic normal faults as reverse and left-lateral strike-slip faults, uplift of mountain ranges bordering the basin, and deposition of up to 10 km of clastic sediment.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)