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Upper Toarcian ostracod assemblages from Boca da Mata, Alvaiázere, Central Portugal, are described to complement earlier work on the ostracods of the Toarcian GSSP at Peniche, western Portugal. A total of 44 species are recorded and the following new taxa described: Cytheropterina ainsworthi sp. nov., Eucytherura alvaiazerensis sp. nov., Otocythere iberobritannica sp. nov., Ophektycythere gen. nov. with O. herrrigi sp. nov., O. mataensis sp. nov. and O.? sicoensis sp. nov. The assemblages reflect oxygenated fully marine, sublittoral shallow water conditions in a proximal margin of the Lusitanian Basin. The species spectrum has most in common with material described from Western Europe especially the Fastnet Basin, offshore Ireland. Lowermost Aalenian assemblages contain some Toarcian species but also new taxa not studied in detail. [ABSTRACT FROM AUTHOR]

The stratigraphical occurrence of ostracod assemblages of the uppermost Pliensbachian (emaciatum Biozone) and Lower-Middle Toarcian (polymorphum, levisoni and bifrons biozones) at Peniche, western Portugal, is reported, an interval that encompasses the Toarcian Global Boundary Stratotype Section and Point (GSSP) and the Toarcian Oceanic Anoxic Event as represented by a Carbon Isotope Excursion (CIE). The broad pattern of ostracod faunal turnover and replacement in the Peniche GSSP section before, during and after the CIE, including "survivor" and "Lazarus" species, and the stepwise extinction of metacopine ostracods is similar to that described from elsewhere in Western Europe. Assemblage composition is closest to material described from the Fastnet Basin, offshore SW Ireland, and the Mochras Farm Borehole, Wales, Great Britain. The d13C record at Peniche and Mochras Farm facilitates a very refined comparison of ranges of species in common between the two sites. The species Bairdia paramolesta sp. nov. and Kinkelinella ventrocarinata sp. nov. are described. [ABSTRACT FROM AUTHOR]

Here, we present an integrated stratigraphical study across the Sinemurian-Pliensbachian interval cropping out into the Portuguese reference section of S. Pedro de Moel (Lusitanian Basin). Characterized by marl-limestone alternations of the Água de Madeiros Formation (subdivided into Polvoeira and Praia da Pedra Lisa members), this succession is particularly dominated by organic-rich facies (black shales) and contains a diverse fauna of benthic and nektonic macro fossils. This stratigraphic and sedimentary setting is the basis for a high-resolution carbon isotope study, constrained by new ammonite biochronostratigraphic determinations and other palaeontological data. The new ammonite collections characterize the Oxynotum and Raricostatum chronozones and the Raricostatum, Macdonnelli and Aplanatum subchronozones, and accurately identify the Sinemurian-Pliensbachian boundary in this western Iberian margin setting. Carbon isotope measurements were made from bulk carbonate (δ13Ccarb) from 351 samples, representing the Oxynotum to earliest Jamesoni (early Taylori) Chronozone intervals. The carbon isotope values exhibited a large range, varying between +2.85‰ in the Oxynotum Subchronozone to very negative values observed in some limestone beds from the Raricostatum Subchronozone (lowest reaching -6.7‰), a variation clearly controlled by lithological and facies changes. Despite these strong anomalous isotopically light values (below -2‰), which are clearly associated with organic matter degradation and early diagenesis, the δ13Ccarb curve shows a long-term negative trend across the Oxynotum to the early Taylori Subchronozone interval. This tendency is reversed around 5 m above the Sinemurian-Pliensbachian boundary, and the δ13Ccarb values become positive correlative with an absence of organic matter and argillaceous sediments in the limestone beds of Praia da Pedra Lisa Member. Although the δ13C data recorded across the Sinemurian-Pliensbachian of the Lusitanian Basin had been controlled by internal depositional conditions, the general evolution of carbon isotopes agrees with the trend recognized in other basins. [ABSTRACT FROM AUTHOR]

Data on lipids, carbohydrates and proteins of the most expressive black shale (s.l.) intervals of the Early--Late Pliensbachian (Early Jurassic, ˜187 Ma) organic-rich hemipelagic series of the Lusitanian Basin (Portugal) were determined using a method that has been successfully applied over the last two decades in the characterization of biomass and very immature sediments. The goal of this paper is to test the applicability of these techniques to the ancient geological record. To our knowledge, this is the first time that this type of biogeochemical data from sedimentary series older than Oligocene is reported and tentatively used for palaeoenvironmental/diagenetic inferences. Carbohydrates and proteins are present in low concentrations, reaching up to 385.13 and 451.13 µg/g rock, respectively. The main variations are observed in the lipid contents, ranging from 197.67 to 8446.36 µg/g rock. The samples with the highest amounts of lipids seem to correlate with low [O2] time intervals determined by independent data, such as organic petrography, micropalaeontology and sedimentology. This was probably related with selective lipid preservation under oxygen and hydrogen sulfide-rich depleted environments. The good overall match between the determined lipid contents and specific depositional/early diagenetical conditions seem to favor the idea that the easy to perform and inexpensive method applied here has the potential to add useful information to the study of ancient organic-rich carbonate sedimentary series. [ABSTRACT FROM AUTHOR]