Structural Modeling and Restoration of a Syn-Tectonic Deep-Water Basin Fill, Ainsa Basin, Northern Spain

Matthew Hoffman
Chevron Center of Research Excellence (CoRE) Department of Geology and Geological Engineering Colorado School of Mines Golden, CO; [email protected]

Actively growing structures influencing coeval deep-water deposition are present in some of the world's largest hydrocarbon producing regions (i.e. Gulf of Mexico, Indonesia, Nigeria and Angola). Ainsa Basin in the Spanish Pyrenees is unique in that it is one of the few locations in the world where the interaction of deep-water deposits and compressional growth structures can be studied in detail and in three-dimensions.

The Middle to Upper Eocene turbidite systems of the Campodarbe Group (Ainsa, Morillo, and Guaso systems) exhibit stratigraphic architectures indicative of syn-growth deposition related to basin-bounding anticlines (Mediano, Boltaña, and Añislco anticlines). This study aims to reconstruct four syn-growth horizons and one pre-growth horizon in a three-dimensional structural model of the basin. The base of each syn-growth turbidite system (condensed section) is mapped and used in the reconstruction to define successive basin paleo-bathymetry during stages of basin-fill. Syn-growth horizon reconstruction is constrained by (1) new surface orientation measurements, (2) balanced cross-sections, and (3) limited sub-surface data. Along strike variation of the bounding anticlines was documented in order to constrain the three-dimensional geometry of the pre-growth surface. Preliminary results show a thickening of the Ainsa system adjacent to the Añislco anticline, which borders Ainsa Basin to the north, that is not reflected within the Morillo system, suggesting the cessation of growth on the anticline. This structural model will be combined with detailed facies and architectural studies of the Morillo system to provide an enhanced understanding of structural control on deep-water sedimentation in a compressional setting.

AAPG Search and Discovery Article #90083 © 2008 AAPG Foundation Grants in Aid