ABSTRACT
In 1984-85 the Geological Survey of Finland carried out countrywide geochemical mapping of till at 1:2.000,000 to establish the regional contents and behaviour of major and trace elements and to provide material for the first Geochemical Atlas of Finland. This chapter suggests that the methods used can be applied in most parts of the world where sediments are of local origin, and even in tropical areas, where laterite can serve as the sampling material. It proposes that low density geochemical mapping should be done wherever possible, to establish the balance of the key nutritional elements on the earth's surface. The fine fraction of till was analyzed by multi-element techniques, i.e. plasma emission spectrometry (ICP-AES) and epithermal neutron activation analysis (ENAA). A good correspondence can be seen between the elemental concentrations in till and the bedrock type, e.g. the Ca/K ratio is high in northern Finland where basaltic lavas prevail and low in southern Finland where granitoid rocks prevail.
