Geochemical atlas of Finland; till

The Regional Till Geochemical Mapping data set gives information on the concentrations of 37 elements in unaltered basal till. The samples have been taken, in 1983, from an unaltered basal till (C horizon) below the groundwater table at a depth of ca. 70 cm (variation 50-200 cm) with a density of one sample per 300 km2. The data set covers the whole of Finland with a total sample amount of 1056. The samples are composite field samples. The calculated sample point coordinates entered in the data set have been obtained from the centroid coordinates of five subsamples. The subsamples have been collected from a 300 m x 1000 m rectangular-shaped area. In Northern Finland, samples have been obtained by including samples taken previously in the Nordkallot Project. The samples have been sieved for analysis at a grain size grade less than 0.06 mm. The samples have been analysed for total elemental concentrations and aqua regia concentrations. Total concentrations have been determined either by neutron activation analysis (method code 900N) or by total dissolution with strong concentrated mineral acids (method code 312P). The analysis code for aqua regia dissolution is 511P. Gold and palladium have been determined with a analysis method based on flameless atomic absorption (519U). The sulfur concentration has been determined with a LECO analyser (810L). Further, total concentrations (312P) and aqua regia soluble concentrations (511P) were determined from Southern Finland and Mid-Finland samples with a grain size grade less than two millimetres. The original purpose of the Regional Till Geochemical Mapping data set was national geochemical general mapping and ore exploration. Other uses are, for example, estimating the baseline concentration of the soil, the nutrient levels of forest soil, assessing the buffering capacity of base cations in the soil and evaluating the weathering rate.