Datación por luminiscencia de depósitos fluviales y eólicos en el margen occidental de Galicia

Abstract

The use and development ofthe technique of absolute dating by luminescence over the last years has alJowed to know the burlal time of sediments along the Holocene and the Upper Pleistocene, within the limits of the technique, up to 150 or 200ka for the OSL signal from quartz grains, and 500 ka or more, for the pIR-IRSL signal from feldspars. Those signals are generated through crystal-Iattice charge redistribution in mineral grains due to their exposure to natural radiation within sediments, until a saturation level that does not alJow reaching older ages than referred above. There exist a number of constraints that must be considered in order to apply the most approprlate dating procedure. For instance, and unlike what happens in aeolian sediments whose luminescence signal is completely-bleached by sunlight during wind transport befare deposition, fluvial sediments can ove reame incomplete bleaching of the luminescence signal due to turbidity conditions of the water transporting them prior to their deposition, which could lead to the presence of an inherited residual charge added to these generated during the burial time and which would result in an age overestimation. In this PhD. Thesis, luminescence techniques were applied in fluvial and aeolian sediments of unknown age until now, developed in the Atlantic margin of the Northwest of the Iberian Península. This allowed to test the technique as wel! as to ¡ncrease the knowledge of the coastal evolution in this region during the last glacial and interglacial Quaternary phases. To this end, some of the coastal-fluvial deposits developed in the lower Mero river basin (A Coruña, Galicia, Spain) and the mouth of the Ulla river at Catoira (Pontevedra, Galicia, Spain) have been selected, as well as so me outcrops corresponding to ancient dunes along the Atlantic coastline of Galicia in the provinces of A Coruña and Pontevedra.