Determination of platinum-group elements and forty two other elements in two candidate Danish Cretaceous-Tertiary boundary clay reference materials by INAA, ENAA and RNAA

Ruthenium, rhodium, palladium, osmium, iridium and platinum (PGEs) and fort y two other elements in two candidate geological Cretaceous-Tertiary bounda ry clay reference materials taken from the "Fish Clay", Stevns Klint, Denma rk, were determined by a combination of neutron activation analysis (NAA) c onsisting of instrumental, epithermal and radiochemical NAA with or without nickel sulfide fire assay preconcentration. The accuracy of the experiment al values was assessed by the comparative analysis of the certified referen ce materials.