New palynological and isotopic data for the Triassic of the western Cantabrian Mountains (Spain)

Triassic carbonate rocks of the western Cantabrian Mountains, northern Spain, have long been attributed to the Muschelkalk facies, and as such have been correlated with other Middle Triassic carbonate units of the Iberian Peninsula. Data on palynological assemblages here presented, point to a Ladinian-lower Carnian age of the upper part of the Buntsandstein facies in this area. In addition, the 87Sr/86Sr ratio of the limestones formerly attributed to the Muschelkalk facies indicates a Norian or Norian-Rhaetian boundary age. These findings also imply that the position of the marine coast during the Middle Triassic Tethys transgression should be moved to a more easterly position, in the Basque Country.Las rocas carbonatadas triásicas que afloran en la zona occidental de la Cordillera Cantábrica en el norte de España, han sido tradicionalmente atribuidas al Muschelkalk por correlación con las unidades carbonatadas del Triásico Medio de otras áreas de la Península Ibérica. Las asociaciones palinológicas encontradas en la parte superior de las facies Buntsandstein que afloran en esta área, indican una edad Ladiniense-Carniense inferior. La relación 87Sr/86Sr de los niveles de calizas atribuidos anteriormente al Muschelkalk, son propios de los carbonatos de edad Noriense o Noriense-Rhetiense. Estos datos implican, además, que la posición de la línea de máximo avance del mar del Tethys hacia occidente durante el Triásico Medio se situó en una posición más oriental y dentro del País Vasco

Nuevos datos palinológicos e isotópicos del Triásico de la Cordillera Cantábrica occidental (España)

Triassic carbonate rocks of the western Cantabrian Mountains, northern Spain, have long been attributed to the Muschelkalk faciès, and as such have been correlated with other Middle Triassic carbonate units of the Iberian Peninsula. Data on palynological assemblages here presented, point to a Ladinian-lower Carnian age of the upper part of the Buntsandstein faciès in this area. In addition, the 87Sr/86Sr ratio of the limestones formerly attributed to the Muschelkalk faciès indicates a Norian or Norian-Rhaetian boundary age. These findings also imply that the position of the marine coast during the Middle Triassic Tethys transgression should be moved to a more easterly position, in the Basque Country.Las rocas carbonatadas triásicas que afloran en la zona occidental de la Cordillera Cantábrica en el norte de España, han sido tradicionalmente atribuidas al Muschelkalk por correlación con las unidades carbonatadas del Triásico Medio de otras áreas de la Península Ibérica. Las asociaciones palinológicas encontradas en la parte superior de las facies Buntsandstein que afloran en esta área, indican una edad Ladiniense-Carniense inferior. La relación 87Sr/86Sr de los niveles de calizas atribuidos anteriormente al Muschelkalk, son propios de los carbonatos de edad Noriense o Noriense-Rhetiense. Estos datos implican, además, que la posición de la línea de máximo avance del mar del Tethys hacia occidente durante el Triásico Medio se situó en una posición más oriental y dentro del País Vasco.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEMinisterio de Educación y Cienciapu

Palinología del Cretácico Inferior de la sección de Montoria-La Mina (Cuenca Vasco-Cantábrica, España): polen de angiospermas primitivas

La sección del Cretácico Inferior de Montoria-La Mina se encuentra en el margen sur de la Cuenca Vasco-Cantábrica (España). Sus materiales están integrados por una sucesión de lutitas y arcillas con niveles de lignitos y areniscas que se depositaron en un cinturón deltáico, pudiéndose atribuir a la Formación Escucha. Se han obtenido asociaciones palinológicas bien conservadas con un número significativo de palinomorfos que ha permitido realizar estudios de tipo cuantitativo en ocho de los doce niveles analizados. Se ha puesto de manifiesto la existencia de una flora diversa, integrada por cuarenta y cuatro tipos diferentes de criptógamas vasculares y veintiocho de fanerógamas de las divisiones Bryophyta, Lycophyta, Pteridophyta, Pteridospermophyta, Coniferophyta, Cycadophyta/Ginkgophyta, Gnetophyta y Magnoliophyta. Las asociaciones palinológicas se encuentran dominadas por granos de polen anemófilo de Corollina obidosensis e Inaperturopollenites dubius y por esporas psiladas de Cyathidites australis, que indican la existencia de climas cálidos y secos. Es relevante el registro de polen de angiospermas primitivas en las asociaciones estudiadas, correspondiendo a formas de tamaño pequeño, reticuladas y, por lo general, columeladas. Se describen formas inaperturadas, operculadas, monosulcadas y tricotomosulcadas que se han atribuido a los grupos Pre-Afropollis, Clavatipollenites, Liliacidites, Retimonocolpites y Retimonoporites. La aparición de estos grupos polínicos permite relacionar las asociaciones registradas con las de la parte inferior de la Zona I del Grupo Potomac (Maryland, USA) y con las del Cretácico Inferior de Israel. [ABSTRACT] The Lower Cretaceous Montoria-La Mina section is located in the extreme southern part of the Basque–Cantabrian Basin (Spain). The succession might be included into the Escucha Formation and contains siltstones and clays with interbedded deltaic lignite and sandstone rocks. The palynological analysis of these rocks shows well preserved miospore assemblages with significant numbers of specimens in eight of the twelve analysed horizons. A diverse flora composed of forty four vascular cryptogams and twenty eight fanerogams are identified, included in the divisions Bryophyta, Lycophyta, Pteridophyta, Pteridospermophyta, Coniferophyta, Cycadophyta/Ginkgophyta, Gnetophyta and Magnoliophyta. The palynological assemblages are dominated by anemophilous pollen grains of Corollina obidosensis and Inaperturopollenites dubius, as well as psilate spores of Cyathidites australis, which suggest warm and dry climatic conditions. The occurrence of pollen grains of ancient angiosperms is significant in the studied assemblages. They were identified as small-sized, reticulate and generally collumelate miospores. Inaperturate, operculate, monosulcate and trichotomosulcate forms attributed to the Pre-Afropollis, Clavatipollenites, Liliacidites, Retimonocolpites and Retimonoporites pollen groups are described. The appearance of these palynological groups are compared to those in the lower part of Zone I of Potomac Group (Maryland, USA) and in the Lower Cretaceous of Israel

Multiresidue determination of quinolones regulated by the European Union in bovine and porcine plasma. Application of chromatographic and capillary electrophoretic methodologies

This paper presents the multiresidue determination of the series of quinolones regulated by the European Union (marbofloxacin, ciprofloxacin, danofloxacin, enrofloxacin, sarafloxacin, difloxacin, oxolinic acid and flumequine) in bovine and porcine plasma using capillary electrophoresis and liquid chromatography with ultraviolet detection (CE-UV, LC-UV), liquid chromatography-mass spectrometry and -tandem mass spectrometry (LC-MS, LC-MS/MS) methods. These procedures involve a sample preparation by solid-phase extraction for clean-up and preconcentration of the analytes before their injection into the separation system. All methods give satisfactory results in terms of linearity, precision, accuracy and limits of quantification. The suitability of the methods to determine quinolones was evaluated by determining the concentration of enrofloxacin and ciprofloxacin in real samples from pig plasma and cow plasm

Neutron Beam Effects on Spin Exchange Polarized He-3

We have observed depolarization effects when high intensity cold neutron beams are incident on alkali-metal-spin-exchange polarized He-3 cells used as neutron spin filters. This was first observed as a reduction of the maximum attainable He-3 polarization and was attributed to a decrease of alkali-metal polarization, which led us to directly measure alkali-metal polarization and spin relaxation over a range of neutron fluxes at LANSCE and ILL. The data reveal a new alkali-metal spin-relaxation mechanism that approximately scales as the square root of the neutron capture-flux density incident on the cell. This is consistent with an effect proportional to the recombination-limited ion concentration, but is much larger than expected from earlier work.Comment: submitted to Physical Review Letter

New Tetrahedral Global Minimum for the 98-atom Lennard-Jones Cluster

A new atomic cluster structure corresponding to the global minimum of the 98-atom Lennard-Jones cluster has been found using a variant of the basin-hopping global optimization algorithm. The new structure has an unusual tetrahedral symmetry with an energy of -543.665361, which is 0.022404 lower than the previous putative global minimum. The new LJ_98 structure is of particular interest because its tetrahedral symmetry establishes it as one of only three types of exceptions to the general pattern of icosahedral structural motifs for optimal LJ microclusters. Similar to the other exceptions the global minimum is difficult to find because it is at the bottom of a narrow funnel which only becomes thermodynamically most stable at low temperature.Comment: 3 pages, 2 figures, revte

Unbiased Global Optimization of Lennard-Jones Clusters for N <= 201 by Conformational Space Annealing Method

We apply the conformational space annealing (CSA) method to the Lennard-Jones clusters and find all known lowest energy configurations up to 201 atoms, without using extra information of the problem such as the structures of the known global energy minima. In addition, the robustness of the algorithm with respect to the randomness of initial conditions of the problem is demonstrated by ten successful independent runs up to 183 atoms. Our results indicate that the CSA method is a general and yet efficient global optimization algorithm applicable to many systems.Comment: revtex, 4 pages, 2 figures. Physical Review Letters, in pres