Abstract The Ainsa turbidite system is part of the slope fill of the Ainsa basin. It was deposited in foredeep and wedge-top depozones. The base of the system is an angular unconformity; the top is a gradual facies change to a mudstone-dominated unit. Maximum thickness is 305 m (1000 ft) and preserved width and length are 8 km (4.9 mi) and 9 km (5.6 mi), respectively. Mean paleoflow is to the northwest, parallel to the main axis of the basin. The system consists of three cycles of channel complex development and abandonment. In the basal part of these cycles, there are one or two channel complexes that are nearly straight. The dimensions are greater than 1.5 km (0.9 mi wide), greater than 9 km (5.6 mi long), and up to 100 m (328 ft) thick. channel complexes are bounded laterally and above by thin beds that represent overbank and frontal-splay deposits, or by slump deposits with a dominant mudstone composition. Synchronous thrusting and folding caused the angular character of the basal unconformity, the marked thinning of the system towards the basin margins, the progressively rotated cycle boundaries, the frequent multilateral architecture of channel-complexes, and in some cases, channel-complex divergences around growing anticlines. The outcrop corresponds to a partial section of one of the two channel complexes in the lowermost cycle. Mean paleoflow is to the west-northwest (290°) and the outcrop trends 160°–340°. The base of the channel complex is not exposed. It is interpreted to be a few meters (>10 ft) below the stratigraphically lowest beds in the outcrop.

Abstract The Arro turbidites (Eocene San Vicente Formation) were deposited as part of the infill of the Ainsa basin during the foredeep stage of basin development. Their maximum thickness is 180 m (590 ft) with a preserved length of 16 km (10 mi) and width of 4 km (2.5 mi). Net-to-gross is approximately 40%. The Arro turbidites have been interpreted as a canyon-mouth sheet system that was deposited in a base-of-slope setting. The system is elongate with deposition occurring in the axis of the foredeep basin. Flanking the deposits was an active margin slope. The Arro turbidites have been correlated updip to a canyon fill that is incised in shelf deposits. The Los Molinos road outcrop is a partial section of the Arro turbidites. This section is 180 m (590 ft) long, transverse to the northwest-directed paleoflow. It is located approximately 4.2 km (2.6 mi) from the canyon-fill locality. Here, the Arro turbidites rest on top of a mudstone succession and reach their maximum thickness (180 m [590 ft]). Four classes of architectural elements, ranging in thickness from 1–20 m (3–66 ft), are present in the outcrop. These include 1) mudstone-rich, thin-bed elements (TM) with net-to-gross up to 30%, 2) sandstone-rich, thin-bed elements (TS), with variable net- to-gross (30–70%) and common erosive bedding, 3) thick-bed elements (C), mostly channel forms, with net-to-gross up to 90%, and 4) slump-deformed, mudstone-dominated units (SM). The lower interval of the studied succession (lower two-thirds of exposure) contains abundant slumps and thin beds. channel forms are rare, and where present,