The Eurogeosurveys Geochemical Mapping of Agricultural and Grazing Land Soil Project (GEMAS) - Evaluation of Quality Control Results of Aqua Regia Extraction Analysis

Hafnium ( Hf ) and zirconium ( Zr ) concentrations measured in over 4100 agricultural soil samples from E urope were assessed with the focus on their relationship to the distribution of aeolian deposits, such as loess and coversands. Comparison of extractable ( aqua regia ; ICP‐MS ) and total ( XRFS ) concentrations shows that only 1.0 to 1.7% of the total Hf and Zr is chemically extractable because of the resistant nature of their host minerals. Resistate minerals, such as zircon, are commonly found in the predominantly silty fraction of loess deposits. In this study a statistical analysis of total Hf and Zr soil data from areas with and without loess was carried out to derive threshold values of 10 mg kg −1 ( Hf ) and 318 mg kg −1 ( Zr ). These values were subsequently applied across the project area in an attempt to indicate the presence of aeolian deposits. The spatial distribution of above‐threshold concentrations suggests a more extensive and coherent loess belt across central and eastern E urope, providing additional evidence of loess across B rittany, A quitaine and near the V osges mountains in F rance as well as in the basins of central and northern S pain. Above‐threshold concentrations were also detected in loess regardless of its thickness, emphasising the importance of the abundance of zircon in the upper part of the soil profile rather than the actual thickness of the deposit. Soil data however, failed to indicate various loess facies within most of the P annonian B asin, suggesting that this approach only works where deposits contain a sufficient amount of zircon. This may also explain why the extensive coversands across northern G ermany and P oland were largely undetected. This study demonstrates that continental‐scale soil geochemical data can help identify and map the distribution of zircon‐rich loess and coversand, and subsequently enhance and improve current knowledge of the extent of these deposits.

Mollisol

10.1111/bor.12029

Cite

Citations (49)

The geochemistry of niobium and its distribution and relative mobility in agricultural soils of Europe

Geochemistry Exploration Environment Analysis (2012)

Andreas Scheib Dee Flight Manfred Birke Timo Tarvainen J. Locutura

The Geochemical Mapping of Agricultural and Grazing Land Soil (GEMAS) project provides soil geochemical data for over 50 elements at a density of 1 sample per 2500 km 2 across the European continent. Median baseline total concentrations of niobium (Nb) determined by X-ray fluorescence spectrometry in the <2 mm fraction of 2108 ploughed agricultural soil (0–20 cm) and 2024 grazing land (0–10 cm) samples are 13 and 12 mg/kg, respectively. These concentration levels are more than 23 times higher than the median extractable concentration of Nb obtained by aqua regia digestion. Thus >95% of Nb in soils can be considered ‘immobile’. All anomalous soil concentrations can be related to geogenic processes. Many of the elevated Nb concentrations are underlain by Hercynian granitic intrusions and alkaline volcanic rocks. High Nb levels also correspond to the occurrence of residual soils over karst areas of southeast Europe and, to some extent, loess deposits of central and Eastern Europe. Lowest Nb concentrations are found in soils developed on most recent glacial sediments of northern Europe. Comparison of the aqua regia extractable concentrations of Nb in both sample types collected within <450 m of each other show that concentrations are on average 0.12 mg/kg (15.4%) higher in grazing land soils, suggesting an influence of different land-use practises.

10.1144/geochem2011-096

Cite

Citations (29)

Comparing results from two continental geochemical surveys to world soil composition and deriving Predicted Empirical Global Soil (PEGS2) reference values

Earth and Planetary Science Letters (2012)

Patrice de Caritat Clemens Reimann

Analytical data for 10 major oxides (Al2O3, CaO, Fe2O3, K2O, MgO, MnO, Na2O, P2O5, SiO2 and TiO2), 16 total trace elements (As, Ba, Ce, Co, Cr, Ga, Nb, Ni, Pb, Rb, Sr, Th, V, Y, Zn and Zr), 14 aqua regia extracted elements (Ag, As, Bi, Cd, Ce, Co, Cs, Cu, Fe, La, Li, Mn, Mo and Pb), Loss On Ignition (LOI) and pH from 3526 soil samples from two continents (Australia and Europe) are presented and compared to (1) the composition of the upper continental crust, (2) published world soil average values, and (3) data from other continental-scale soil surveys. It can be demonstrated that average upper continental crust values do not provide reliable estimates for natural concentrations of elements in soils. For many elements there exist substantial differences between published world soil averages and the median concentrations observed on two continents. Direct comparison with other continental datasets is hampered by the fact that often mean, instead of the statistically more robust median, is reported. Using a database of the worldwide distribution of lithological units, it can be demonstrated that lithology is a poor predictor of soil chemistry. Climate-related processes such as glaciation and weathering are strong modifiers of the geochemical signature inherited from bedrock during pedogenesis. To overcome existing shortcomings of predicted global or world soil geochemical reference values, we propose Preliminary Empirical Global Soil reference values based on analytical results of a representative number of soil samples from two continents (PEGS2).

Bedrock

Lithology

Aqua regia

10.1016/j.epsl.2011.12.033

Cite

Citations (73)

Arsenic in agricultural and grazing land soils of Europe

Applied Geochemistry (2012)

Timo Tarvainen Stefano Albanese Manfred Birke Michal Poňavič Clemens Reimann

Aqua regia

Agricultural land

Soil test