Abstract

The middle Eocene Ainsa turbidite system developed as part of the slope fill of the Ainsa basin in wedge-top and foredeep depozones. It comprises several channel complexes that are separated vertically by fine-grained deposits accounting for episodes of relative abandonment. The external geometry and internal architecture of the Ainsa turbidite system was reconstructed in 3-D. This required the creation of a suitable architectural scheme. Moreover, the analysis of the reconstructions allowed us to draw general conclusions about the relationships between tectonics and sedimentation. Cycles of tectonic activity and quiescence are interpreted as the mechanisms responsible for the general organization of the system in three cycles of channel-complex development and abandonment, as well as for changes in the stacking pattern of channel complexes. Moreover, it is shown that the position of some channel complexes, like the Ainsa-1 quarry, was controlled by growing anticlines. The characterization of the outcrop reported in Chapter 84, this volume, is from the Ainsa-1-quarry channel complex, which is located at the base of the system. This outcrop is one of the best ones in the Ainsa area. It is dominated by channel fills reflecting different sediment transport capacities, but other depositional elements are also present. These are ordered in two sequences of channel forms; the lower one is of the mixed erosional-depositional type, and the upper one represents the reactivation of the system.