Construcción de modelos estructurales 3D: ejemplo de la Cuenca de Ainsa (Pirineo meridional central)

In this paper a methodology is presented which optimizes the use of field geological data, subsurface structural data, and geological knowledge in the generation of 3-D geological reconstructions. Structural reconstructions are solved in a purely 3-D approach, avoiding the use of cross-sections and other intermediate steps which can be the source of unexpected errors and can mask the real 3-D geometry of geological structures. This is done through the use o f a 3-D dip-domain method for surface construction which is combined with the implementation o f 3-D restoration techniques as a fundamental step in reconstruction. This methodology is aimed at resolving 3-D geometries in folded areas, and regions with variable thickness stratigraphy. This methodology is applied to data from the early to middle Eocene turbidite succession of the Ainsa basin whose sedimentary evolution was affected by the development of thrust-related and detachment folds. The external and internal geometry of four turbidite systems outcropping around the Bui I syncline (Ainsa basin, Spanish Pyrenees) have been reconstructed with reservoir-scale resolution in three dimensions. The 3- D reconstruction o f the BuiI syncline reveals the synsedimentary growth of an intrabasinal anticline and the foreland lithospheric flexure associated to tectonic loading north of the Ainsa basin.