The Ainsa quarry outcrop revisited via orientation models built from LIDAR data

The Ainsa quarry outcrop is located 1.5 km south of Ainsa town, in southern Pyrenees, Spain. The strata in the exposure are Eocene, and deposited in a submarine slope setting undergoing synchronous thrusting and related folding. They have tectonic dips of about 22º to the WSW. The succession comprises a 20 m thick turbidite sandstone body (Figure 1) sandwiched between mudstone-dominated mass-transport deposits, together representing the Ainsa-1 turbidite channel-complex. The outcrop has been the subject of numerous studies that have contributed to the global understanding of turbidite systems (Mutti and Normark, 1987; Schuppers, 1995; Clark and Pickering 1996). This succession is also important in that it has been regarded as an analogue for reservoirs in the offshore West Africa. The outcrop section is about 400 m long, and its map view shows as a very open angle, limiting the validity of 3-D reconstructions away from the outcrop face to mere extrusion. However, the quarry face is clean and allows for the observation of multiple bedding surfaces, specially the sharp soles of turbidite sandstones on top of mudstone beds (Figure 1). These surfaces were studied from their LIDAR point cloud expression. The results, a local 3-D reconstruction, will be used to revisit an existing depositional and architectural interpretation of the outcrop (Arbués et al. 2008) that had been built on the basis of conventional outcrop characterization techniques.<br>