Connaissances stratigraphiques sur la base du Mésozoique portugais

In Portugal, the Mesozoic lower part is principally composed of conglomeratic, arenitic and pelitic deposits, which are here and there associated with carbonates rocks and evaporites. The Germanic Triassic succession is not observed. The Muschelkalk facies do not exist. Carbonates formation, and some thick evaporites deposits (Keuper facies) are of early Jurassic in age. The thick red beds accumulations deposited in a continental environment are Triassic. In Coimbra area the oldest palynomorphs found are Camian-Norian. In South Portugal (Algarve), the triassic serie must be more complete with a lower Triassic rich in Stegocephales bone-beds.

Miocene sediments from Foz da Fonte and Penedo sections (Lower Tagus basin): clay minerals and isotopic data

Eight depositional sequences (DS) delimited by regional disconformities had been recognized in the Miocene of Lisbon and Setúbal Peninsula areas. In the case of the western coast of the Setúbal Peninsula, outcrops consisting of Lower Burdigalian to Lower Tortonian sediments were studied. The stratigraphic zonography and the environmental considerations are mainly supported on data concerning to foraminifera, ostracoda, vertebrates and palynomorphs. The first mineralogical and geochemical data determined for Foz da Fonte, Penedo Sul and Penedo Norte sedimentary sequences are presented. These analytical data mainly correspond to the sediments' fine fractions. Mineralogical data are based on X-ray diffraction (XRD), carried out on both the less than 38 nm and 2 nm fractions. Qualitative and semi-quantitative determinations of clay and non-clay minerals were obtained for both fractions. The clay minerals assemblages complete the lithostratigraphic and paleoenvironmental data obtained by stratigraphic and palaeontological studies. Some palaeomagnetic and isotopic data are discussed and correlated with the mineralogical data. Multivariate data analysis (Principal Components Analysis) of the mineralogical data was carried out using both R-mode and Q-mode factor analysis.