Relations between natural gamma radiation, mineralogical and chemical properties of clays and muds from the Aveiro region - Portugal

The Aveiro region (Fig. I) corresponds to the northern sector of the Portuguese Occidental Meso-Cenozoic sedimeritary basin. At the Aveiro region the upper Cretaceous is represented by the "Argilas de Aveiro" formation (Campanian-Maastrichtian), which are composed of greenish clays and marls intercalated with thin dolomitic layers. In the region, the outcrops of this formation are relatively extensive, with a maximum length (oriented N-S) of about 20 Km and a maximum width of about 5 Km, partially covered by quaternary old beach and alluvial deposits.