Abstract: Basement Uplifts, Basin Structuration and Fluid Dynamics, Oriente Basin, Ecuador

Michael P. Coward, Alison C. Ries, Camille Spencer, Richard Spencer

The Cordillera Orientale, the Napo-Cutucu Uplifts and the low amplitude anticlines of the Oriente Basin of Ecuador show evidence of growth during the Late Cretaceous-Eocene and the Miocene-Recent. The Oriente Basin is essentially a hinterland basin in that the main Andean sutures and crustal scale thrusts dip to the E beneath the Cordillera and the western edge of the basin. Hence there was relatively little migration of the basin margin throughout the Tertiary. Many of the block bounding faults are reworked basement structures, either as steep basement fabrics or Mesozoic extensional systems. Steep faults in the basement pass up into broad hangingwall anticlines. The basement faults develop footwall and/or hangingwall collapse structures and local backthrust systems. Hydrocarbons mig ated into the Oriente Basin during the Paleogene from kitchens in the deeper parts of the Putumayo-Llanos Basin in Colombia and the Maranon Basin in Peru. Fresh water flowed through the basin from the main Cordillera in the W. The fluid dynamics were modified during Neogene block reactivation, modifying and locally destroying the reservoirs and redistributing hydrocarbons.

AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994