Abstract Cretaceous rocks crop out extensively in the three main Alpine orogenic belts of Spain: the Betic Cordillera, the Pyrenees and the Iberian Ranges. These rocks, deformed during Cenozoic Alpine convergence, are almost entirely sedimentary (with the exception of rare volcanic and meta-morphic rocks) and were deposited in an enormous variety of environments ranging from alluvial fans to pelagic seas. There were four main basins – Betic, Pyrenean, Basque-Cantabrian and Iberian (Fig. 12.1 ) – each of which originated in Triassic and Jurassic times in response to continental break-up at the start of the Alpine cycle. They subsequently underwent a polyphase evolution in the Cretaceous period when palaeo-geography and sedimentation in Iberia were strongly influenced by the relative movements of the contiguous Eurasian and African plates. Initiation of the North Atlantic spreading in earliest Cretaceous time led to a decrease in relative sinistral motion between Iberia and Africa (e.g. Ziegler 1988 a ). This was followed by a phase of rapid counterclockwise rotation of Iberia relative to Europe and the progressive opening of the Bay of Biscay, which lasted from late Aptian to early Campanian times (e.g. Olivet 1996 ). Finally, a third phase of basin evolution was heralded by the onset of Late Cretaceous oblique convergence between Africa and Europe (e.g. Savostin et al . 1986 ; Reicherter & Pletsch 2000 ). In addition to this changing tectonic setting, other factors, such as climate and eustasy, were also important controlling influences. The Cretaceous climate of Iberia