C. Arias

Orbitolina episodes in carbonate platform evolution:the early Aptian model from SE Spain

Abstract Among the Orbitolininae, Palorbitolina lenticularis (Blumenbach) is a common facies marker in Upper Barremian-Lower Aptian shallow water Mesogean deposits and was hitherto ascribed to specific, but contrasting paleoenvironments within the carbonate platform facies suites. The Albacete-Prebetic area (SE Spain) illustrates a model in which the Palorbitolina facies spread over the whole platform system. The development of the Palorbitolina sediments coincided with a transgressive trend at the end of an important terrigenous period. This model could also be applied to similar Middle Crotaceous “Orbitolina” facies.

Hauterivian shallow marine calcareous biogenic mounds: S.E.Spain

Abstract Hauterivian biogenic deposits from the Prebetic northern margin near Caudete (Albacete Province, southeastern Spain) are represented by low domed bodies, less than 10 m thick, surrounded by bioclastic sediments and capped by siliciclastics. They consist of a coral, stromatoporoid and microbial framework with cavities filled by mud, rapidly lithified. Intermound bioclastics, derived from the mound organic community, reflect high energy conditions and shallow water settings. Mound growth and architecture were controlled by nutrient fluxes and internal light gradients. Comparisons with closely related structures from the Palaeozoic and the Recent show some similarities but also significant differences; the example documented here also departs from other Cretaceous occurrences.

Integration of subsidence and sequence stratigraphic analyses in the Cretaceous carbonate platforms of the Prebetic (Jumilla–Yecla Region), Spain

Abstract An integrated analysis of subsidence and sequence stratigraphy of the Cretaceous successions of the Jumilla–Yecla Region (Betics, SE Spain) is supported by abundant stratigraphical, sedimentological and palaeontological data, with the aim to document and explain the accommodation changes that controlled the evolution and architecture of the carbonate platforms generated during that time on the southern continental margin of Iberia. The Cretaceous shallow marine carbonates and clastics that extensively crop out in the Jumilla–Yecla Region are divided into 11 sequence sets (major stratigraphic units bounded by tectonically induced unconformities), which can be subdivided into several third order depositional sequences and their constituent system tracts. All these genetic units build up a regional chronostratigraphic framework, which is herein used to support subsidence calculations. From the results of the subsidence analysis, seven intervals with characteristic tectonosedimentary patterns were distinguished for Cretaceous time. From these intervals, the first three (respectively early Tithonian–early late Berriasian, late Berriasian–late Hauterivian, and latest Hauterivian to earliest late Albian) were controlled by extensional tectonics, strong enough to mask, during most part of the time, the long-term thermal subsidence inherent to the continental margin. This tectonism was related to the Iberia–Africa divergence and the opening of the North Atlantic. Later, the fourth interval (late Albian–mid Cenomanian) and the sixth interval (late Coniacian to late Santonian) were characterised regionally by, overall, homogeneous subsidence patterns controlled by thermal subsidence, sediment loading and a relative tectonic quiescence. Finally, the fifth and the seventh intervals (respectively latest Cenomanian–early Coniacian and Campanian–Maastrichtian) were characterised by strong tectonic movements and complex subsidence patterns which were related to changes in intraplate stresses related to the onset of the convergence between Africa and Iberia and with the evolution of the Bay of Biscay.