ABSTRACT
Geochemical mapping includes sampling of natural material, chemical analysis of the samples, and illustration of the analytical results on maps. A high standard is required in the reproducibility of geochemical patterns for geomedicine. In geomedicine an easily extractable part is generally of more interest than the total contents because it would normally be a closer approximation of the fraction available for organisms than are the total contents. A combination of physical, chemical, and biological processes controls the dispersion from the sources to the sampling site. In Norway, nation-wide geochemical maps have also been prepared based on chemical analysis of soil and water. In geochemistry computers are used extensively in the preparation of maps. Usually the limits of a restricted number of concentration intervals are determined by some statistical method; these intervals are represented on maps by a restricted number of symbols, colors or isoconcentration curves.
