Abstract: Paleogene Geological Evolution of Eastern Onshore Maracaibo Basin

Sabrina Sarzalejo, Bruno De Toni, Freddy Leon, Alonso Navarro, Ivan Rodriguez

A regional study was undertaken to establish the geological evolution of the Eastern Onshore Maracaibo Basin, specifically in the area called Zulia Oriental. The dataset used for this propose included 710 km of seismic data, 25 well bores, biostratigraphic reports and high resolution analysis of palynomorphs, forams and nannofossils. This regional study was performed in an area that suffered during the Paleogene the effects of oblique convergence and A-type subduction to produce a large foredeep basin. The thickest foredeep sedimentation occurred in the study area where more than ten thousand feet of Eocene deposits have been reported from seismic data.

Sequence stratigraphic principles were applied to establish the stratigraphic framework throughout the area. An intensive tectonic deformation together with very high sedimentation rates have made the understanding of this geological evolution a difficult task. Biostratigraphic dating was done, where possible, in these rapidly deposited predominantly continental units, to unravel the history of the area. The lack of wells with representative Paleogene units translates into poor stratigraphical control, especially in the northern region. Second order transgressive and regressive cycles prove to be very useful in establishing a general correlation of wells throughout the area. Seismic profiles have imaged changes in the geometry of the synkinematic Cenozoic sedimentation that are closel related to a complex multiphase basement tectonics.

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