366 research outputs found

    Ordovician and Silurian igneous rocks and orthogeneisses in the Catalonian Coastel Ranges

    Get PDF
    These rocks exhibit calc-alkaline affinities and may have originated by partial melting of the crust in a post-collision, anorogenic setting. Orthogneisses derived from biotite-bearing leucogranites occur within aprobably cambrian heterogeneous series. Petrological and geochemical features suggest that they might be genetically related to the ordovician vulcanites. Basic sills and volcanoclastic rocks occur intercalated within a mainly pelitic formation in the lower part of the Silurian sequence. The silurian igneous rocks are alkali basalts and may reflect an extensional regime

    Ordovician and Silurian igneous rocks and orthogeneisses in the Catalonian Coastel Ranges

    Get PDF
    These rocks exhibit calc-alkaline affinities and may have originated by partial melting of the crust in a post-collision, anorogenic setting. Orthogneisses derived from biotite-bearing leucogranites occur within aprobably cambrian heterogeneous series. Petrological and geochemical features suggest that they might be genetically related to the ordovician vulcanites. Basic sills and volcanoclastic rocks occur intercalated within a mainly pelitic formation in the lower part of the Silurian sequence. The silurian igneous rocks are alkali basalts and may reflect an extensional regime

    Geochemistry of A Espenuca two-mica granite: origin and evolution

    Get PDF
    [Abstract] The A Espenuca two-mica granite, situated in the northern sector ofthe Central Iberian Zone, was variably deformed by the Valdoviño Fault. Deformation intensity is observed to increase from W to E, also being more intense in the northern half. Results of the geochemical study of the less deformed granite facies, known in the regionalliterature as the «weakly deformed facies», are presented. Chemical variations are faint (DSi02 z 4%) and reflect a whole composition close to the granite minimum. Analyzed samples correspond to alkali-dch(Na20+K20, x = 8.4 %), CaO-depleted rocks « 0.9 %), showing very low values for the B (=Fe+Mg+Ti) parameter x = 30, and a marked peraluminous character, A/CNK, x =1.16 (range 1.1-1.26), which from the mineralogical point of view is traduced in the occurrence of muscovite (± garnet). The rocks studied are depleted in REE (LREE =75.77-189.83; x = 117.4), notably in the HREE. They exhibit considerably fractionated pattern (La/Lu)n x = 50 as well as important Eu negative anomalies (Eu/Eu*, x = 0.36). These rocks can be linked by fractionated crystallization processes. Massbalance calculations indicate crystallization ratios < 30%, the fractionated minerals being Kfs, Bt, PI. These values to explain the trace element variations observed in the different samples. The chemical-mineralogical composition of analyzed facies suggests an origin by partial melting of crustal rocks (either pelites, schists, meta-greywackes or orthoderived materials) at considerable depths, where garnet constitutes a restite stable phase. Nevertheless, calculated models show that not aH these materials equally adjust as source to the granite magma. The best fits are obtained considering a source similar to 0110 de Sapo gneisses. Key Words: Two-mica granite, fractional crystallization, partia

    The Santa Elena stock (Jaén). An intrusion genetically independent fram the magmatic association of the Los Pedroches Batolith

    Get PDF
    [Abstract] The Santa Elena stock has been classically considered as belonging to the magmatic association ofthe Los Pedroches Batolith. The stock is intrusive into psammo-pelitic materials Ordovician to Carboniferousin age. The Santa Elena stock is composed of biotite granodiorite to tonalite with gabbro-diorite as enclaves ofvariable size outcropping in northern sectors ofthe intrusion. Pelitic xenoliths ofvarious sizes, likely related to magma stopping, are common through the massif. The Santa Elena stock is intruded by a dike complex made of aplite and ore-bearing quartz veins. The two main lithological units exhibit different geochemical features with local evidence ofmagmamixing between acid and basic types. The granodioritetonalite is chemically homogeneous regarding the content of major and trace elements, including REE. These rocks correspond to mildly peraluminous terms ofan alumino-cafemic association ofcalc-alkaline character.The gabbrodiorite enclaves are meta-aluminous and clearly deviate from the geochemical trend defined by granodiorite and tonalite. The rocks from the Santa Elena stock are very different from the common granodiorite types ofthe Los Pedroches Batolith. It appears from the petrological and geochemical data that the Santa Elena stock corresponds to an independent and different magmafrom that at the origin ofthe Los Pedroches to which it had been classically associated

    The Linares granite (Jaén): cartography, petrology and geochemistry

    Get PDF
    [Abstract] Magma emplacement within the Linares granite, a part of the Los Pedroches Batholith, took place in the sequence: biotite granodiorite with microgranular enclaves, biotite monzogranites, and dike swarm complexo Dikes are: WNWESE rhyolite to rhyodacite, aplopegmatite and abundant NE-SW ore-bearing quartz. The Linares intrusion and psamo-pelitic Carboniferous host metasediments (Los Pedroches Culm) are, in part, discordantly covered by Mesozoic (Trias) and Tertiary to Quaternary terrigenous deposits. Bulk rock chemistry of granodiorite shows minor variations in Si02 (64.75... 67 wt %) and REE contents (LREE = 158 -160 ppm), and nearly constant Al CNK (ISA) ratio (1.1 - 1.15). Monzogranites have higher Si02 (66.87 - 68.4 wt %), alkali and REE contents (LREE = 168 - 193 ppm), with A/CNK (ISA) ratio of 1.06 - 1.09. Both granodiorite and monzogranites are peraluminous rocks that may correspond to an aluminous association or to evolved terms of an aluminocafemic association (Debon & Lefort, 1983). Variation diagrams for major and trace elements, including REE, of granodiorite and monzogranites are compatible with magmatic differentiation processes by fractional crystallization starting from a primary granodioritic magma

    Progesterona en leche, 1. Radio inmuno análisis de progesterona en leche.

    Get PDF
    Se desarrolló un método de análisis de progesterona en leche por RIA. En la estandarización de la técnica el tiempo de incubación antígeno-anticuerpo se redujo a 10 minutos. La leche dentro del sistema actuó como ligante no específico de la progesterona. Este efecto fue superado mediante la escogencia de una alicuota (10 ul) adecuada y la correlación introducida en la curva de calibración al adicionarle leche sin hormona detectable. La alícuota de 10 ul mencionada anteriormente contiene cantidades medibles dentro de los límites de máxima resolución del método (6,25 - 400 pg 0.1 ml). El uso de una suspensión de carbón-dextrano para la separación de la fracción libre y ligada no pudo ser sustituido por el de un segundo antisuero. Los valores en la leche se correlacionaron en forma altamente significativa con la existente en la sangre, no obstante, las concentraciones en leche fueron 5,2 veces más altas que en sangre. Estas dos circunstancias han ampliado la aplicabilidad y sensibilidad del método. Mediante análisis estadístico de datos allegados durante dos años, se comprobó la sensibilidad reproductiva y precisiónGanado de leche-Ganadería lech

    Progesterona en leche, 2. Parámetros reproductivos evaluados mediante el análisis de progesterona en leche.

    Get PDF
    Se estudió en un grupo de 44 vacas la correlación de los perfiles típicos y atípicos, anestros e índices de preñez, diagnóstico precoz de preñez, incidencia de inseminaciones y ovulaciones perdidas, mediante la determinación de progesterona en leche por radioinmunoanálisis. Estos análisis se hicieron en el laboratorio de hormonas del Instituto de Asuntos Nucleares. Se estableció un criterio para definir si un perfil progestacional era típico o atípico, encontrando que las vacas con perfil progestacional tienden a presentar menos días abiertos. El promedio de días abiertos para las vacas con perfil progestacional típico fue de 161 y para aquellas con perfil progestacional atípico fue de 310. La duración del período anestro no difirió notablemente entre vacas preñadas y no preñadas. El índice de precisión para el diagnóstico precoz (21 días) de preñez fue positivo del 78 por ciento, mientras que para el negativo (vacas vacias) fue del 99 por ciento. El día post-inseminación más adecuado para la toma de muestra utilizada en este diagnóstico de preñez fue el día 21, aunque la diferencia no fue significativa con referencia a los días 19 y 23. El método permitió medir el número de inseminaciones y ovulaciones perdidasGanado de leche-Ganadería lech

    Petrology and geochemistry of Cardeña-Virgen de La Cabeza pluton (batholith of Los Pedroches)

    Get PDF
    [Resumen] El plutón de Cardeña-Virgen de La Cabeza es uno de los cuerpos intrusivos que integran la unidad granítica del batolito de Los Pedroches. Dentro de este plutón, se ha establecido el emplazamiento sucesivo en el tiempo de: 1) adamellitas biotíticas, 2) granitos biotíticos porfídicos ± cordierita, 3) leucogranitos ± cordierita. Las adamellitas biotíticas muestran localmente paso gradual hacia las facies granodioríticas del batolito. Existe además un importante complejo filoniano que se intruye posteriormente, formado por diques riodacíticos de dirección NO-SE, lamprófidos, aplitas, pegmatitas y filones mineralizados· de cuarzo. Geoquímicamente, la adamellita y el granito biotítico porfídico constituyen una asociación alumino-cafémica de carácter calcoalcalino. Los enclaves anfibólicos (términos cafémicos) poseen carácter metaaluminoso. Los leucogranitos se desvían de la tendencia general definiendo una asociación aluminosa y leucocrática. Los diagramas de variación para elementos mayores, menores, trazas y tierras.raras de adamellitas, granitos biotíticos porfídicos y de granodioritas, rocas, estas últimas, con las que se encuentran íntimamente relacionadas, son compatibles con procesos de diferenciación magmática por cristalización fraccionada a partir de un magma inicial de composición granodiorítica más básico[Abstract] The Cardeña-Virgen de La Cabeza intrusion belongs to the granitic unit of the Los Pedroches batholith. the chronology of the intrusion of the different rocktypes that make up the pluton is as follows: 1) biotitic adamellite, 2) porphyritic, cordierite-bearing, biotitic granite. 3) cordierite bearing leucogranite. The biotitic adamellite locally shows a transition to the granodioritic facies of the batholith. A great amount ofNW-SW oriented dikes with rhyodacitic composition intruded subsequently. Lampophyres, aplites, pegmatites and ore-bearing quartz veins complete the dike complexo Adamellite and biotitic ganite define an aluminous-cafemic association with calcalkaline affinity. The amphibole-bearing enclaves represent the cafemic terms of the series and have a metaaluminous character.The leucogranite deviates from the general trend defining and aluminous, leucocratic association. Variation diagrams for major, minor and trace elements, including REE, of adamallite, porphyritic biotitic granite and granodiorite of the main pluton (which is intimately associated with the Cardeña-Virgen de La Cabeza intrusion) suggest a process of magmatic differentiation through fractional crystallization starting from a slightly more basic granodioritic magma
    corecore