The sequence is predominatly composed of shallow-water carbonate grains but can be interpreted using the current siliclastic submarine-fan models. Basin-plain to outer-fan, braided-channel midfan, and large channel-fill sequences can be recognized. The source of the carbonate grains was a platform developed on an uplifted Hercynian horst to the west of present mainland Portugal. The fan sequence overlies restricted basin deposits with organic-rich mudstones and shales. This association of restricted basin facies and a thick (over 300 m) carbonate grainstone could be an attractive hydrocarbon play. However, such limestone sequences are easily misinterpreted as in situ shelf carbonates.--Modified journal abstract.