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A 380 m thick Aptian platform to basin transition has been studied along a 16 km long transect of excellent and continuous outcrops in NE Spain. The series has been dated using biostratigraphy (foraminifera and ammonites) and carbon-isotope stratigraphy, and has been subdivided at four scales of depositional sequences. The Aptian marine succession is subdivided into two-large scale sequences separated by a middle Aptian sub-aerial exposure surface. A characteristic trend of the floral-faunal fossil assemblages is present, which evolves from orbitolinid-ooid dominated ramps in Sequence I-1, to a coral-stromatoporoid-microbialite dominated platform in Sequence I-2, to a rudist-dominated platform top in Sequence II-1, and finally to a second episode of orbitolinid-ooid dominated ramp system in Sequence II-2. There was an influx of siliciclastic sediments at the base and at the top of this succession. The detailed carbon-isotope curve measured along the Miravete section and covering almost the complete Aptian succession, is compared with published Aptian curves recorded in both basinal and carbonate platform settings along the northern and southern NeoTethys margins. It shows that the Galve sub-basin curve represents all the major isotope excursions of the lower and upper Aptian, in a dominantly shallow-water succession.

Facies analysis of the upper Kimmeridgian rocks in the outcrops located near Ricla (Zaragoza province, northeast Spain) and the integration of the resultant data in a broader context (the northern part of the Iberian Basin), has produced two general models showing the facies distribution and the processes that controlled the sedimentation in the Kimmeridgian carbonate ramp. Using these two models the transition from shallow to relatively deep environments of the carbonate ramp is examined in detail. Model 1 corresponds to the development of a mixed carbonate-siliciclastic ramp during a slow rise and stillstand of sea level (Sequence 1-HST), whereas Model 2 represents the growth of a pure carbonate ramp during a rapid rise of sea level (Sequence 2-TST).Carbonate production was higher in the shallow ramp domains (coral reefs and oolitic shoals in Model 1 and reefs in Model 2) than in deeper domains, where there is no indication of signi®cant pelagic or benthic production. The activity of unidirectional return¯ows induced by winter storms and hurricanes, played an important role in the redistribution of the sediment across the ramp, generating different coarse-grained deposits. In the inner and mid-ramp settings dunes, lower scale bedforms and tempestites occur in Model 1, and storm lobes, bars and tempestites in Model 2. Moreover, a signi®cant bulk of the carbonate mud produced in shallow areas would eventually be resedimented in the outer ramp as suspended load in the density currents. Stillstand of sea level in Model 1 involved a rapid progradation of the inner and proximal mid-ramp carbonate and siliciclastic facies. The rapid relative sea level rise of Model 2 is determined by the dominance of the carbonate facies and by the presence of aggradational geometries in the transitional area between shallow and deep-ramp domains. The presence of relatively thick sections in the outer-ramp settings (instead of condensed sections, as observed in Model 1) during times of sea level rise (Model 2) can mainly be explained by the increase of the shallow production in the reef dominated areas. q

No counterparts to epeiric-sea carbonate ramps are known in present-day environments. This hinders the interpretation of the factors controlling the growth and evolution of these depositional settings. In this study we analyse the facies and geometries of two Jurassic examples both from outcrop study and through computer modelling. This analysis is constrained by two important features of these Oxfordian and Kimmeridgian ramps: firstly, they are very well exposed, allowing accurate reconstruction of a 200-km section from proximal to distal ramp environments, and, secondly, a time framework for correlation, section reconstruction and modelling is provided by a well-defined ammonite biostratigraphy. The modelling results in a synthetic stratigraphy which closely matches the reconstructed cross-sections and, when integrated with the field study, constrains and provides additional quantitative data on the following aspects of carbonate ramp systems.Resedimentation by storms is an important process in maintaining the ramp profile through time. Down-ramp transport distances of between 25 and 40 km are indicated from the distribution of storm beds and shallow-water allochems and from model-matching known stratigraphic thicknesses and geometries.biozones indicates that shallow-water carbonate production was 1-2 orders of magnitude less than that predicted for present-day open-marine carbonate platforms. Deeper-water production rates were reduced by lesser amounts. These proportionally higher, outer-ramp production rates also help to maintain ramp geometries through time.The enigmatic slope crest of ramps is shown to result from a combination of higher, shallow-water production and erosion rates, together with loss of accommodation during highstands and high-stillstands in the modelled sea-level curves.The most parsimonious modelling of the two ramp sequences comes from a relative sea-level curve composed of a linear subsidence component superposed by 20-and 100-kyr cycles on a third-order cycle. The third-order cycles and their timing do not correspond to those of the Exxon curve.Modelling sediment production within the time constraints from the ammonite