Sphenopteris asturica nueva especie

Se describe un ejemplar (holotipo) de la Cuenca de Tineo (Asturias) que se atribuye a una nueva especie del género Sphenopteris caracterizada por sus raquis acanalados que portan pínulas de contorno triangular alargado de bordes lobulados, con nervio central neto y sinuoso decurrente sobre el raquis que emite nervios secundarios de forma pecopterideana. Presenta esta especie semejanzas con Sph. burgkensis Sterzel (= Sph. leptophylla Bunb.) y con Sph. goniopteroides Lesqu.Se figura también un ejemplar de Commentry (Francia) así como dos pequeños fragmentos de Puerto Ventana. Todos los ejemplares figurados así como otro citado procedente de Surroca (Gerona) proceden de niveles estefanienses

Contribution a la connaissance de la flore carbonifère des pyrénñees basques (Larroun et Ibantelly)

In this work we descrive fossil plants collected in Piri- neos mountains. Here are classified 33 species of which thirteen lias been stated in the coaldfield for first time. The coaldfield is dated as the upper Stephanian B or as the low Stepha- nian C

Les cuticules dispersées du crétacé et du tertiaire de colombie

With the inventory of the scattered cuticles of the Cerrejón Basin (State of Guajira), the writers take up the comparison of the various cretaceous and tertiary deposits in Colombia. This first study deals with specimens gathered in the carbonaceous deposits located on the limits of the Hato Nuevo y Cerrejón formations (Upper Paleocene-Lower Eocene). The taxonomic value of the epidermical characteristics preserved due to the fossilization has led the writers to make some reserves as to the nomenclature and the systematic of the scattered cuticles.Con el inventario de las cutículas dispersas de la cuenca de Cerrejón (Departamento de Guajira), los autores comienzan la comparación de los diferentes yacimientoscretácicos y terciarios de Colombia. Esta primera publicación se refiere a los ejemplares tomados en los niveles carbonosos situados al límite de las Formaciones Hato Nuevo y Cerrejón (Paleoceno superior-Eoceno inferior).La importancia taxonómica de los caracteres epidérmicos conservados por la fosilización lleva a los autores a hacer algunas reservas sobre la nomenclatura y la sistemática de las cutículas dispersas.Avec l'inventaire des cuticules dispersées du Bassin de Cerrejón (Département de Guajira), les auteurs abordent la comparaison -des diffetents gisements crétacés ettertiaires de Ia Colombie. Cette première note concerne des échantillons prélevés dans les niveaux charbonneux situés à la limite des formations Hato Nuevo et Cerrejón (Paléocène -supérieur- Eocène inférieur). La valeur taxinomique des caractères épidermiques conservés par la fossilisation conduit les auteurs à faire quelques réserves sur la nomenclature et la systématique des cuticules dispersées. / Resumen. Con el inventario de las cutículas dispersas de la cuenca de Cerrejón (Departamentode Guajira), los autores comienzan la comparación de los diferentes yacimientos cretácicos y terciarios de Colombia. Esta primera publicación se refiere a los ejemplares tomados en los niveles carbonosos situados al límite de las Formaciones Hato Nuevo y Cerrejón (Paleoceno superior-Eoceno inferior).La importancia taxonómica de los caracteres epidérmicos conservados por la fosilización lleva a los autores a hacer algunas reservas sobre la nomenclatura y la sistemática de las cutículas dispersas. /  Abstract. With the inventory of the scattered cuticles of the Cerrejón Basin (State of Guajira), the writers take up the comparison of the various cretaceous and tertiary deposits in Colombia. This first study deals with specimens gathered in the carbonaceous deposits located on the limits of the Hato Nuevo y Cerrejón formations (Upper Paleocene-Lower Eocene). The taxonomic value of the epidermical characteristics preserved due to the fossilization has led the writers to make some reserves as to the nomenclature and the systematic of the scattered cuticles

El Pérmico y el Triásico de la región de Molina de Aragón (Cordillera Ibérica): día II

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

El Pérmico y el Triásico del borde sur-este del Sistema Central: día IV

Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

SÉDIMENTOLOGIE ET BIOSTRATIGRAPHIE DE LA FORMATION TRIASIQUE MUFARA (SICILE OCCIDENTALE): FORAMINIFÈRES, CONODONTES, PALYNOMORPHES

Nella parte nord-occidentale della Sicilia, la Formazione Mufara costituisce la base comune delle successioni appartenenti ai domini paleogeografici Panormide e Imerese. Questa formazione, costiruita da un'alternanza di marne gialle e di calcari marnosi, calcareniti e calciruditi, affiora in modo discontinuo in tutta la regione presa in esame. Inclusi nelle marne si osservano anche blocchi esotici di calcari grigi recifali d'affinità Panormide. Lo studio micropaleontologico (Conodonti, Palinomorfi) dei calcari marnosi e marne ha permesso di attribuire a questa successione un'età carnica (Tuvaliano, con esclusione del Tuvaliano terminale). L'analisi sedimentologica dei livelli calcarenitici e calciruditici, che contengono una microfauna a Foraminiferi d'età ladino-carnica e d'affinità Panormide, induce a ritenere un'origine torbiditica per le intercalazioni calcaree della Formazione Mufara ed anche ad attribuire un'età ante-norica all'individuazione della piattaforma Panormide

Sudden changes in fluvial style across the Permian / Triassic boundary in the eastern Iberian Ranges, Spain: Analysis of possible causes

The sedimentary record of the Late Permian and Early Triassic of the eastern Iberian Ranges shows four major, sudden, or very rapid, vertical changes in fluvial style. The Late Permian sedimentary cycle starts with the Boniches Formation, of alluvial fan-braided fluvial origin, which grades vertically over within a few metres into the Alcotas Formation, deposited by low to high sinuosity, avulsion-prone rivers with extensive floodplains. The Alcotas Formation contains calcimorphic soils, plant remains and pollen and spore assemblages. However, the upper third of the unit is devoid of all organic remains and soils and is characterized by a dominant red colour, the sandstone levels were deposited by high-sinuosity, meandering rivers. This major change took place during the Late Permian and is probably coeval with the emplacement of the Emeishan basaltic Large Igneous Province (LIP) in SE China. Rocks of the Boniches and Alcotas Formations are separated by an angular unconformity from the overlying strata, which consist of the Late Permian conglomeratic Hoz del Gallo Formation, of alluvial fan–gravel braided fluvial origin and the sandy Cañizar Formation, of low-sinuosity sandy river origin. The Permian– Triassic boundary lies, probably between the upper part of the Hoz del Gallo Formation and the first metres of the Cañizar Formation. Late Permian pollen and spore assemblages have been found in the Hoz del Gallo Formation but the Cañizar Formation is barren, with the exception of an Anisian (Middle Triassic) assemblage at the top. Tectonic extensional pulses in the Iberian Basin caused the changes observed between the lower and upper parts of the Boniches Formation, at the base of the Hoz del Gallo Formation and between the lower and upper part of this Formation. The changes observed in the uppermost part of the Alcotas Formation are not easily explained by tectonic causes, nor those in the passage from the Hoz del Gallo Formation to the Cañizar Formation. Similar sedimentary characteristics of the sandy Cañizar Formation such as amalgamated sandstone bodies, erosion and reactivation surfaces, dominant trough cross-stratification, tabular geometry, absence of plant remains and pollen and spores, and absence of silts and clays to those of coeval formations in places as far away as Australia, South Africa and Brazil suggest a global rather than local cause for these abrupt changes in fluvial style. This global cause was probably die-off of plant cover over extensive areas of the catchment, related to the end of the Permian mass extinction and possibly related to the emplacement of the West Siberian basaltic Large Igneous Province (LIP), responsible for drastic atmospheric and marine changes