Abstract: Identification of the best sequence of planktonic foraminiferal events that is reproducible across the Coniacian–Santonian boundary interval is determined by comparison of data from three reference sections: the Cantera de Margas section at Olazagutia in northern Spain (Global Boundary Stratotype Section and Point [GSSP] for the base of the Santonian Stage), the Ten Mile Creek section in southern Texas (candidate GSSP stratotype for the base of the Santonian Stage), and Tanzania Drilling Project (TDP) Site 39 drilled in Tanzania. In the stratotype section, the GSSP is marked by the lowest occurrence of the inoceramid Cladoceramus undulatoplicatus (= Platyceramus undulatoplicatus ), which occurs within the planktonic foraminiferal Dicarinella asymetrica Zone, and by secondary microfossil events and a negative 0.3‰ excursion in δ 13 C. The same bio- and chemostratigraphic records have been identified in the Ten Mile Creek section in Texas. In Tanzania, Globotruncana linneiana , a GSSP secondary planktonic foraminiferal marker event, has been used in the absence of Cl. undulatoplicatus and of correlative chemostratigraphic tie points. The planktonic foraminiferal composition in the three stratigraphic sections is similar, although discrepancies are observed in the reproducibility of some bioevents. Similarities between sections include the same order of appearances of the index species Sigalia carpatica , Costellagerina pilula , and G. linneiana in the Cantera de Margas section and TDP Site 39, and the absence of the single-keeled globotruncanids ( Globotruncanita stuartiformis , Globotruncanita elevata ) in the Cantera de Margas and Ten Mile Creek sections. This apparent diachronism mostly pertains to the paleobiogeographic distributions and ecological preferences of species that developed and diversified under specific paleoenvironmental conditions. Overall, the study of the three sections allows derivation of a more accurate and reproducible sequence of planktonic foraminiferal events across the Coniacian–Santonian boundary interval. It demonstrates the reliability of the surface dweller C. pilula as the best proxy for recognition of the base of the Santonian Stage from epicontinental to open-ocean depositional settings and in a wide range of paleolatitudes.

Abstract The productivity of wells in fractured reservoirs depends, in terms of rate and sustainability, on the heterogeneity and variable connectivity of the open fracture network. Outcrop studies in Cretaceous carbonates from the Catalan Pyrenees illuminate this issue and reveal the degree of uncertainty associated with the interpretation of fracture data from wells and seismic. Three examples are chosen to provide verifiable data, parameters and concepts which can be applied to the workflow of fractured reservoir characterization. We discuss fracture properties and distributions in the subseismic volume, the coupled behaviour between litho-mechanical properties, in situ stress and fracturing, and the permeability properties of fault damage zones. The outcrops also highlight some of the difficulties involved in constructing static reservoir models and evaluating fracture interpretations derived from software-based techniques such as surface curvature.

Abstract Obtaining estimates of the rates of sedimentation and frequency of depositional events at high resolution from pre-Quaternary successions is rarely possible, particularly in coarse-grained clastic successions of continental basin margins. In the Miocene strata of the Ebro Basin, northern Spain, basin-marginal deposits interpreted as the products of alluvial fans are part of the continuous aggradational fill of a basin of internal drainage. A palaeomagnetic reversal stratigraphy has been established in basin-centre sediments and correlation across to the basin margin makes it possible to estimate the rate of aggradation within the fan successions to be 90 mm ka −1 . The deposits of one alluvial fan near the village of Linás de Marcuello have been analysed in the context of these rates to provide estimates of the frequency of depositional events. This analysis suggests that deposition on gravel bars approximately 700 mm thick in stream channel deposits occurred at intervals of 70–200 years over a 2.2 myr time period. This is the first time an estimate of the frequency of depositional events has been obtained at such high resolution from a pre-Quaternary alluvial fan succession.