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Benedetto De Vivo, Università degli Studi di Napoli "Federico II" (Italy)
Annamaria Lima, Università degli Studi di Napoli "Federico II" (Italy)
Maria Anna Bove, Università degli Studi di Napoli "Federico II" (Italy)
Giuseppe Sabatini, Università degli Studi di Siena (Italy)
Pietro Frizzo, Università degli Studi di Padova (Italy)
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Other contributors: S. Albanese, D. Cicchella, L.A. Di Lella, G. Protano, L. Raccagli.
In 1994 the FOREGS (Forum of the European Geological Surveys) became the European subcommittee of the IGCP 360 (Global Geochemical Baselines project) (1) an international project which aimed to realize the recommendations of IGCP 259 (2). The 26 nations of the FOREGS project contributed to the Geochemical Atlas of Europe, collecting national geochemical data.
The Italian Geochemical Atlas addresses the need for a large scale geochemical mapping based on FOREGS standards. In the framework of the GTN (Global Terrestrial Network), Italy has been divided in eight 160 x 160 Km square cells. However to improve sampling homogeneity, the sampling grid has been extended to 28 cells.
Stream water (W), stream sediments (S), floodplain sediments (F), topsoils (T) and subsoils (C) samples have been collected in 58 locations, homogeneously distributed along Italy. For FOREGS purposes, we sampled 50 sites all over Italian territory; these data have been used for the first edition of the Geochemical Atlas of Europe (3, 4). Between April and September 2005, further samples have been collected in eight new sites, to improve sampling homogeneity for the Italian territory. The new sampling sites are located in sub-cells of southern Italy. In both phases FOREGS sampling and sample handling procedures have been implemented (5). Every sample site has been documented by two photographs. Soil and sediment samples have been dried at 40°C with infrared lamps, crushed in agate mortar, and sieved (< 0.063 mm fraction), before being sent for analysis.
The geochemical data used for the FOREGS project and the new data from sub-cells of southern Italy have been processed using ArcView GIS®, and a new Multifractal IDW method available in the software GeoDAS® (6). Interpolated map have been overlayed by dots, showing real concentration of elements site by site. Radius of dots is function of element concentrations and they have been classified by mean of a cumulative frequency graph. A total of 360 maps, showing elemental distributions for the whole Italian territory, have been produced.
Data show that, even, at large scale, some elements distributions are function of the lithologies following the major geo-lithological structures and lineaments. In particular, the Roman-Neapolitan alkaline volcanic province is very well individuated along the Tyrrhenian sea. Maps also highlight mineralized areas in southern Sardinia.
(1) Plant J.A. et al., 1996. J. Geoch. Expl. 59, 123-146
(2) Darnley A.G. et al., 1995. Final report of IGCP Project 259. 2nd rev. ed., Paris, UNESCO, 122
(3) Salminen R. (Ed.) et al., 2005. Geological suvey of Finland, Espoo
(4) De Vos W., Tarvainen T. (Eds.) et al., 2006. Geological suvey of Finland, Espoo
(5) Salminen R. et al., 1998. Geological Survey of Finland, Espoo 1998, 16-29
(6) Cheng Q. et al., 2001. The 20th Intern. Geochem. Explor. Symposium (IGES). Santiago de Chile, 42-43
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