FOREGS | Soils summary information


As its contribution to the IUGS/IAGC Global Geochemical Baselines Programme, the Forum of European Geological Surveys (FOREGS, now EuroGeoSurveys), through its component surveys, collected various environmental materials (including three types of soil — organic top layer, minerogenic top and sub soils) to create geochemical baseline maps for Europe.

For the drainage samples and soils this was done at a scale that averages out to about one sample per 4700 km2.

A two part geochemical atlas of Europe has been published (Salminen et al., 2005; De Vos et al., 2006) and databases, maps and atlases are readily and freely available from web pages hosted by the Geological Survey of Finland (GTK).

Sample site selection was based on the Global Reference Network (GRN) grid cells developed for the purpose of Global Geochemical Baseline Mapping (Darnley et al., 1995), each cell being 160 x 160 km.

The soil sampling procedure is described in detail in Salminen et al. (1998) and summarised below. The target was to collect from five 'random' sites within each cell.

The British Geological Survey collected the FOREGS samples for the UK in August–October 1998. Sixty top and sub soil samples were collected and 28 humus samples.

Soil sampling and analytical methodology

A large variety of sampling media were used in this project including:

  • Residual soil, upper horizon (topsoil) 0–25 cm without the top organic layer (<2 mm)
  • Residual soil, lower (C) horizon (subsoil); a 25 cm layer within a depth range of 50–200 cm (<2 mm)
  • Humus where present

Samples in the UK were collected with a stainless steel trowel and stored in Kraft paper bags. Suitable sampling sites were selected in an area where 3–5 pits could be dug to observe and sample the soil profile.

Each sample was a composite of 3–5 samples, the minimum distance between any two subsamples being 5 m. Living surface vegetation, fresh litter, big roots and rock fragments (stones) were removed. Samples were dried at a temperature not higher than 40ºC, disaggregated in a porcelain bowl, sieved through a 2 mm nylon screen and subsequently pulverised to <0.063 mm in an agate disc mill.

Top and sub soils were analysed at various laboratories across Europe by XRFS-WD, ICP-MS (following mixed acid extraction), ICP-AES (following aqua regia extraction), Hg analyser and a granulometric method for total organic carbon (TOC).

Data availability

Geochemical results and maps are available from FOREGS Geochemical Atlas of Europe hosted by the Finnish Geological Survey (GTK).

Data files take the form of a collection of zipped MS Excel files from which individual country subsets can be extracted using the country code field.

Excess sample powders were transferred in 2009 to the National Geoscience Data Centre (NGDC), British Geological Survey, Keyworth, Nottingham, UK.

References and links

Darnley, A G, Bjorklund, A, Bolviken, B. et al.  1995.  A Global Geochemical Database for Environmental and Resource Management. Earth Science Series No. 19, UNESCO Publishing, Paris, 122 pp.

De Vos, W, and Tarvainen, T. (ed.) et al.  2006.   Geochemical Atlas of Europe. Part 2 — Interpretation of Geochemical Maps, Additional tables, Figures, Maps, and Related Publications.  Geological Survey of Finland, Otamedia Oy, Espoo, 692 pp.

Salminen, R, Tarvainen, T, Demetriades, A. et al.  1998.  FOREGS Geochemical Mapping Field Manual.  Geological Survey of Finland, Guide 47.

Salminen, R. (chief ed.) et al.  2005.  Geochemical Atlas of Europe. Part 1 - Background Information, Methodology and Maps.  Geological Survey of Finland, Otamedia Oy, Espoo, 525 pp.