Abstract In order to quantify the petroleum potential of the northwest offshore zone of Cuba, the source-rock potential has been estimated as well as the maturation level and the possible migration pathways. An interpretation of new seismic lines acquired by Compagnie Générale de Géophysique (CGG) has been coupled with field work and well data synthesis. To better characterize the source rocks, Institut Français du Pétrole’s (IFP) Rock-Eval 6 apparatus was run on about 300 samples, and the analyses have been added to the existing IFP and Cuba Petroleo’s (CUPET) databases. Specific kinetic parameters have been computed and modeling has been performed using both 1-D and 2-D models of maturation and migration processes. Several source-rock intervals could be defined in the area: (1) synrift clastic Jurassic, (2) deep-basin Upper Jurassic and Lower Cretaceous carbonate formations, and (3) Middle Cretaceous facies, also carbonates. One of the main results of this study is evidence of the potential of a deep petroleum system in the siliciclastic rift sequence. Shales from a Middle Jurassic synrift section initially appear to have good potential, depending on the maturity of the offshore zone, sufficient depth of the initial synrift half grabens, and the postrift carbonates being several kilometers thick. Upper Jurassic/Lower Cretaceous source rocks associated with deep-water carbonates are largely immature in the deep offshore (Northwest Cuba) except near the coast, where maturity level is high mainly because of thrusting and/or thickness of the foreland deposits. The third source rock is middle Cretaceous (Aptian/Cenomanian), recognized in onshore Cuba as well as in an Ocean Drilling Project (ODP) well; it appears to be an excellent source rock. In the offshore zone, these source rocks are mature only when buried under the flexural basin. The migration pathway under Jurassic evaporites and the middle Cretaceous unconformity (MCU) may lead to long northward as well as lateral migration from the kitchens. In the vicinity of the island of Cuba, in the first 100–150 km northward from the coast, various petroleum systems are active, and the high quality of numerous Cretaceous source-rock intervals show promise for hydrocarbon exploration in the area.

Abstract Sandbox experiments analyzed by computerized X-ray tomography provide relevant models of salt-related contractional structures and improve understanding of the relative importance of the many parameters influencing structural style. In front of thin-skinned fold and thrust belts, the salt layers provide decollement surfaces, which allow the horizontal strain to propagate far toward the edge of the foreland. As shortening increases, older structures forming in front of the system can be overtaken by out-of-sequence faulting and folding. The very low friction coefficient of salt layers induces a symmetric stress system. This promotes pop-up structures rather than asymmetric thrust faults. Salt extrusions are related to former salt ridges or salt walls squeezed by compression and dragged along thrust planes or to local low-pressure zones along crestal tear faults during folding. The salt that spreads out from the fault is rapidly dissolved. The resultant surface collapse structures are progressively filled by a mixture of Recent sediments and reprecipitated evaporites. Salt pinch-outs, either depo-sitional or structural in origin, are a major controlling factor of the deformation geometry in fold and thrust belts. They trigger, either locally or regionally, contractional structures, including folds and thrusts, in rapidly pro-grading passive margins deforming by gravity gliding. In this structural context, salt pinch-outs also thicken due to differential loading and gravity spreading. The structural complexity in inverted grabens or in basement-involved orogenic belts where salt is present is the outcome of many factors. The salt thickness, the preexisting extensional structures, the synsalt and postsalt rifting, and the related distribution of older salt structures and sediments all localize folds and thrusts during later contraction. The relative orientation of the former extensional structures to the younger shortening structures largely controls the style of inversion (fault reactivation versus forced folding and short-cuts). Salt is the main detachment level between the folded cover rocks and the underlying faulted basement. However, secondary detachments, which are common in the overburden, add further complexities—triangle zones in the cores of anticlines and fish-tailed periclinal terminations.

Abstract The various Mediterranean basins are similar in that all contain a Pliocene-Pleistocene clastic sequence, a late Miocene evaporite sequence, and a deep-water pre-late Miocene sequence beneath the evaporites. The basins differ, however, in age and genesis. Western, Tyrrhenian, and Aegean Basins are relatively young (Oligocene to Holocene) marginal types, whereas the Eastern Mediterranean is a remnant of an early Mesozoic ocean with its southern continental margins. The Black Sea is thought to be a back-arc basin possibly as old as Late Cretaceous.