IRIDIUM IN ARCHEAN VOLCANICS OF THE BALTIC SHIELD

Abstract

The authors determined the concentrations not only of iridium and palladium, but also of nickel in basalt and komatiite samples from Late Archean greenstone belts of the Baltic shield. Most information on iridium was obtained by radiochemical neutron-activation analysis, with a precision of ±10 percent. To check the results, the iridium content of two samples was determined by the kinetic method on larger batches with a FKN-57 photocolorimeter. Iridium was determined from the reaction in which monovalent mercury is oxidized by tetravalent cerium. The palladium content of the same samples was also determined, from the reaction whereby the chloride ion is oxidized by trivalent magnesium. Study results are discussed.