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| Titel |
A preliminary bioavailable strontium isotope soil map of Europe. |
| VerfasserIn |
Jurian Hoogewerff, Clemens Reimann, Henriette Ueckermann, Robert Frei, Karin Frei, Thalita van Aswegen, Claudine Stirling, Malcolm Reid, Aaron Clayton, GEMAS Project Team |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250146298
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| Publikation (Nr.) |
 EGU/EGU2017-10317.pdf |
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| Zusammenfassung |
| The GEMAS project collected samples from grazing land (n=2118, 0-20cm depth) and
agricultural soil (n=2211, 0-10cm depth) at a scale of 1 site/2500km2 in most of Europe1.
Elemental analysis using different extractions (Aqua Regia and MMI), whole soil XRF data
and Q-ICPMS lead isotope data have been published1.
Here we report high-precision 87Sr/86Sr results for the first 1000+ samples. To best
represent Sr in plants and animals an ammonium nitrate soil extraction was chosen2. Samples
were measured in three laboratories and shared QC samples demonstrated the robustness of
the complete extraction and measurement protocol. Observed 87Sr/86Sr values range
from 0.7038 to 0.7597 with the majority of samples centring about the median of
0.7092.
Spatial interpolation of the data shows some major trends over Europe with high
87Sr/86Sr in known old intrusive terrains in Scandinavia, Iberia and the Alps. To improve the
spatial resolution we investigated relations between measured 87Sr/86Sr values and other
parameters for which higher spatial density (interpolated) data exists in geological and
lithological databases like IGME50003 and GLiM4. For each sampling site matching
geological age data and lithology were obtained by overlaying sampling locations
on the IGME5000 and GLiM maps and extracting age and lithology information.
All statistical and geospatial manipulations were performed using the R statistical
package.
Overall the 87Sr/86Sr values show a moderate correlation (Pearson R=0.54) with age but
demonstrate varying homogeneity in different lithological units. Within the GEMAS
dataset the strontium isotope ratios correlate most strongly with the lead isotope
results,206Pb/208Pb (R=0.56) indicating a combined age and “crustalinity” effect. Whole soil
Rb (XRF) is slightly higher correlated (R=0.26) with 87Sr/86Sr than extracted Rb (AR)
at R=0.12 indicating some influence of the long term Rb signal in the soil parent
material.
Sodium is the highest correlated whole soil (XRF) element (R=0.33), which initially
might hint at the influence of seaspray as it is often hypothesized that seaspray is a major
source of 87Sr/86Sr variation in coastal regions. To test this hypothesis the distances to the
coast in the major north-westerly wind direction in Europe and the shortest distance to any
coast were calculated. Neither distance measure provided any significant correlation with
87Sr/86Sr values, indicating that the cause of the Na-Sr correlation is not likely to be seaspray,
which would agree with poor correlation with presumably mobile Na in the Aqua Regia
extracts.
In concordance with observations of other authors5 modeling accuracy is improved by
creating separate models for contrasting lithologies; igneous, marine limestones and other
types. Igneous parent material provided the most convincing model using parameters like
age, Rb/Sr ratio and 206Pb/208Pb. Attempts to model 87Sr/86Sr of soil on marine limestones
with the LOWESS version 36 87Sr/86Sr vs. age curve were not convincing although some
pattern similarity could be observed. Uranium and sodium content combined with pH are
reasonable predictors of 87Sr/86Sr in soils on marine limestone parent material. The 87Sr/86Sr
dataset with coordinates and models will be available from the main author after publication
later in 2017.
Reimann, C., et al., (2014). Geologisches Jahrbuch (Reihe B 102),
Schweizerbarth, Hannover.
Voerkelius S. et al., (2010). Food Chemistry. 118 (4), pp. 933-940.
Asch, K., (2003). Geologisches Jahrbuch, SA 3, Schweizerbarth. Hannover.
Hartmann, J., and N. Moosdorf (2012), Geochem. Geophys. Geosyst., 13,
Q12004.
Bataille, C. P. and G. J. Bowen. 2012. Chemical Geology 304-305:39– 52.
J. M. McArthur, et al., Journal of Geology, 2001, volume 109, p. 155–170 |
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