부산대학교 도서관

1 Introduction The study of past climate variations is important to better understand current climate change and its impact on terrestrial ecosystems, particularly at the mid-latitudes (Tegart et al., 1990, [...]
We provided valuable information about the palaeoenvironmental evolution of Southwestern Europe during the last 800 ka through the palynological study of the longest continuous continental Quaternary record in the Iberian Peninsula and in the Southwestern Mediterranean region. The SPD core studied here constituted the longest sequence recovered at the Padul Basin and we improved the chronological precision with respect to previous research. Furthermore, the high sampling resolution provided interesting insights into the main vegetation changes occurred at long-term timescales in the region and allowed correlating these variations with other long continental records of Europe. Dating using palaeomagnetism, amino acid racemisation, U/Th and [.sup.14]C allowed us to construct a robust Bayesian age-depth function, thereby making it possible to determine the chronological framework for the Padul record. From the palynological content of the samples, which were grouped in 11 clusters, we obtained a large variable number of minor pollen variations totalling 21 palynozones identified along the record. From the statistical analysis of the pollen data, some pollen environmental indexes were defned, allowing the reconstruction of palaeotemperature and palaeohumidity conditions. Five climatic scenarios were established: cold/arid, cold/semi-arid, cold/wet, temperate/wet (Mediterranean-climate), and warm/wet (Mediterranean-climate with higher moisture). Of note, the vegetation in the Padul Basin differed from that of other European basins with long pollen records due to regional characteristics, but main palaeoenvironmental trends were in agreement. Pinus, Steppic, Xerophilous, and Mediterranean taxa in the Padul Basin showed a continuous and dominant presence along the whole record, while only in certain periods did humidity increase, refected by the expansion of Spores, Deciduous and Mediterranean taxa (especially in Pz 2, 7 and 13), but without any large expansion of deciduous forest. Comparison with other European records revealed the singular bioclimatic position of the Padul Basin in the Southwestern Mediterranean realm, and this part of Iberia can be considered a Quaternary vegetation refuge, mainly for mesophillous taxa and sclerophyllous oak. Although the biomes of the Padul basin and other European basins could not be compared directly, the main palaeoenvironmental trends were coincident (interstadials were marked by warmer periods and greater humidity, whereas stadials were cooler and more arid). These observations suggest that environmental changes in the Padul Basin were in tune with variations in global palaeoclimatic conditions. Keywords Palynology * Palaeoclimatology * Padul * Quaternary * Southwestern Mediterranean Evolucion paleoambiental de la region suroccidental de Europa durante los ultimos 800 ka En este trabajo proporcionamos informacion valiosa sobre la evolucion paleoambiental de la zona suroccidental de Europa durante los ultimos ca. 800 ka, a traves del estudio palinologico del registro cuaternario continental mas largo de la Peninsula Iberica y del suroeste del Mediterraneo. El sondeo SPD representa la secuencia mas larga de la cuenca de Padul en el que se realizo una mejora del modelo cronologico publicado anteriormente. Asimismo, el muestreo de alta resolucion proporciono informacion importante sobre los principales cambios de vegetacion ocurridos en la zona y permitio correlacionar estas variaciones con las de otros registros continentales europeos largos. La datacion mediante paleomagnetismo, racemizacion de aminoacidos, U/Th y [.sup.14]C permitio construir un modelo cronologico bayesiano robusto del registro de Padul. A partir del contenido de polen de las muestras, que se agruparon en 11 asociaciones, se interpretaron numerosas variaciones menores, pudiendose identifcar 21 palinozonas. A partir del analisis estadistico de los datos de polen se defnieron diversos indices paleambientales que permitieron la reconstruccion de las condiciones de paleotemperatura y paleohumedad. Se establecieron 5 escenarios climaticos: frio/arido, frio/semiarido, frio/humedo, templado/humedo (clima mediterraneo) y calido/humedo (clima mediterraneo con mayor humedad). Cabe destacar que la vegetacion en la cuenca de Padul differia de la de otras cuencas europeas debido a sus caracteristicas locales y regionales, aunque con una buena correspondencia con las tendencias paleoambientales principales a nivel global. Los taxones de pino, plantas esteparias, xeroflos y mediterraneos mostraron una presencia continua y dominante a lo largo de todo el registro, mientras que solamente en ciertos periodos se produjo un incremento de la humedad, refejada en la expansion de esporas y polen de taxones de arboles caducifolios y mediterraneos (especialmente en [Pz.sub.2], 7 y 13), pero sin ninguna gran expansion del bosque caducifolio. La comparacion con otros registros europeos revelo la posicion bioclimatica singular de la cuenca de Padul en el Mediterraneo suroccidental, pudiendo considerarse esta zona de la Peninsula Iberica como un refugio de vegetacion durante el Cuaternario, principalmente de taxones mesoflos y Quercus escleroflos. Aunque los biomas de la cuenca de Padul y otras cuencas europeas no pudieron compararse directamente, las principales tendencias paleoambientales mostraron una coincidencia clara (los periodos interestadiales estuvieron marcados por condiciones mas calidas y de mayor humedad, mientras que los periodos estadiales fueron mas frios y aridos). Estas observaciones sugieren que los cambios en la cuenca de Padul estaban en sintonia con las variaciones paleoclimaticas a nivel mundial. Plalabras clave Palinologia * Palaeoclimatologia * Padul * Cuaternario * Mediterraneo Suroccidental