Publication: Reconstrucción paleoambiental del último ciclo glacial-interglacial en la Iberia continental: La secuencia del Cañizar de Villarquemado (Teruel)
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2013
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Univ Rioja, Serv Publicaciones
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Abstract
La secuencia de El Cañizar de Villarquemado (NE Península Ibérica) constituye un registro excepcional que cubre los últimos ca. 130 000 años de historia ambiental. Los análisis multidisciplinares que se han realizado hasta el momento incluyen un análisis palinológico preliminar y otros indicadores sedimentológicos, como susceptibilidad magnética, análisis geoquímicos de fluorescencia de rayos X (XRF), mineralogía y contenido en carbono orgánico e inorgánico (TOC/TIC). El modelo cronológico se ha realizado combinando dataciones AMS 14C en los 20 m superiores de sedimento y OSL (Luminiscencia Óptica Estimulada) en los 54 m restantes. La secuencia sedimentaria está esencialmente formada por la alternancia de fases con mayor desarrollo de humedales y turberas, con otras de depósitos distales de abanicos aluviales y episodios de lago carbonatado. Los resultados obtenidos hasta el momento confirman que el registro del Cañizar de Villarquemado responde a unas condiciones relativamente húmedas durante un probable MIS6-MIS5, con variaciones en la vegetación regional (esencialmente dominada por Juniperus) que aparecen siempre muy determinadas por la continentalidad de la zona, y que resultan atípicas para lo esperable durante un episodio interglacial como el Eemiense. De todos modos, los márgenes de error adscritos al modelo de edad impiden ciertas precisiones y aseveraciones al respecto. Durante el MIS3 se registra el periodo más árido de toda la secuencia, como confirman los resultados sedimentológicos y los polínicos de algunos intervalos ya disponibles. Sin embargo el MIS2 presenta una gran variabilidad tanto a nivel local, como indican las distintas asociaciones de facies y la vegetación acuática, como a nivel regional, como se deduce de la cubierta vegetal general. El comienzo del Holoceno se registra de manera muy abrupta en cuanto a cambios paleohidrológicos, pero mostrando de nuevo cierta resiliencia de la vegetación, dominada esta vez por pinos y no por Juniperus como en la base de la secuencia, y muy adaptada a las condiciones de extrema continentalidad. El posterior desarrollo de quercíneas junto con la presencia de pinos, apunta situaciones climáticas muy diferentes entre un posible MIS5 y el MIS1.
El Cañizar de Villarquemado sequence (North-eastern Iberian Peninsula) stands as an exceptional palaeoenvironmental record for the last 130 000 years. The preliminary multidisciplinary study carried out so far include pollen and sedimentological analyses, comprising geochemical, X ray fluorescence (XRF), mineralogical, organic and inorganic content (TOC/TIC) analyses. The chronological model has been established combining AMS 14C on the first 20 m of sediment and OSL methods on the remaining 54 m to the bottom. The sedimentary sequence is essentially formed by alternating facies of peatbogs and wetlands with those of distal alluvial fan deposits and others of carbonate lake. The results currently obtained support relatively humid conditions at El Cañizar de Villarquemado during a likely MIS6-MIS5 period, as errors linked to the age model prevent us to guarantee precisely the period boundaries. Despite indications of humidity, the regional vegetation variations during the MIS6-MIS5 period, essentially represented by Juniperus, were constrained by the intense continentality of the area, resulting in unexpected pollen assemblages for an interglacial period as the Eemian. The most arid phase of the sequence is registered during the MIS3, as shown by the available sedimentological and palynological results, while the MIS2 presents greater local and regional variability as proved by the sedimentary facies and aquatics and the other pollen spectra, respectively. The Holocene presents an abrupt onset regarding palaeohydrology while terrestrial vegetation, dominated by pine instead than Juniperus as in the sequence's bottom, show a resilient response as these are well adapted communities to extreme continentality. The later development of both, evergreen and marcescent Quercus, together with the presence of pine woodland, indicate very different climatic conditions between the MIS5 and MIS1 interglacial periods. © Universidad de La Rioja.
El Cañizar de Villarquemado sequence (North-eastern Iberian Peninsula) stands as an exceptional palaeoenvironmental record for the last 130 000 years. The preliminary multidisciplinary study carried out so far include pollen and sedimentological analyses, comprising geochemical, X ray fluorescence (XRF), mineralogical, organic and inorganic content (TOC/TIC) analyses. The chronological model has been established combining AMS 14C on the first 20 m of sediment and OSL methods on the remaining 54 m to the bottom. The sedimentary sequence is essentially formed by alternating facies of peatbogs and wetlands with those of distal alluvial fan deposits and others of carbonate lake. The results currently obtained support relatively humid conditions at El Cañizar de Villarquemado during a likely MIS6-MIS5 period, as errors linked to the age model prevent us to guarantee precisely the period boundaries. Despite indications of humidity, the regional vegetation variations during the MIS6-MIS5 period, essentially represented by Juniperus, were constrained by the intense continentality of the area, resulting in unexpected pollen assemblages for an interglacial period as the Eemian. The most arid phase of the sequence is registered during the MIS3, as shown by the available sedimentological and palynological results, while the MIS2 presents greater local and regional variability as proved by the sedimentary facies and aquatics and the other pollen spectra, respectively. The Holocene presents an abrupt onset regarding palaeohydrology while terrestrial vegetation, dominated by pine instead than Juniperus as in the sequence's bottom, show a resilient response as these are well adapted communities to extreme continentality. The later development of both, evergreen and marcescent Quercus, together with the presence of pine woodland, indicate very different climatic conditions between the MIS5 and MIS1 interglacial periods. © Universidad de La Rioja.