Mineralogical composition of Holocene alluvial deposits from Bardenas Reales of Navarra is studied and compared with the Miocene mudrock substratum. An Early Holocene muddy-silty unit and another Middle-Upper Holocene sandy unit can be differentiated. Mineralogy semiquantitative results are compatible with weak weathering processes affecting the parent materials under humid conditions prior to Holocene. Besides, differences between alluvial units can be explained in terms of bedrock weathering, sedimentary features, recyclingofsediments and pedogenetic processes