Batista, M.J.

Bel-lan, A.

Bidovec, M.

Birke, M.

Breward, Neil

De Vivo, B.

De Vos, W. De

Demetriades, A.

Duris, M.

Halamic, J.

Jordan, G.

Klein, P.

Lax, K.

Lima, A.

Locutura, J.

Mazreku, A.

O'Connor, P.J.

Ottesen, R.T.

Pasieczna, A.

Petersell, V.

Pirc, S.

Reeder, Shaun

Salpeteur, I.

Siewers, U.

Slaninka, I.

Tarvainen, T.

English

NERC Open Research Archive

DISTRIBUTION OF ELEMENTS IN FLOODPLAIN SEDIMENTA. Demetriades1, S. Pirc2, W. De Vos3, R.T. Ottesen4, S. Reeder5,P.J. O’Connor6, M. Bidovec7, B. De Vivo8with contributions byT. Tarvainen9,  M.J. Batista10,K. Lax11, J. Halamic12, A. Pasieczna13, I. Slaninka14, M. Birke15, U. Siewers14, N. Breward5, A. Lima8, M. Duris16, J. Locutura17,A. Bel-lan17, I. Salpeteur18, P. Klein19, G. Jordan20,A. Mazreku21, V. Petersell221Institute of Geology and Mineral Exploration, Athens, Greece;2Geology Department, University of Ljubljana, Ljubljana, Slovenia;3Geological Survey of Belgium, Brussels, Belgium;4Geological Survey of Norway, Norway;5British Geological Survey, Keyworth, Nottingham, United Kingdom;6Geological Survey of Ireland, Dublin, Ireland;7Geological Survey of Slovenia, 1001 Ljubljana, Slovenia8Dipartimento di Scienze della Terra, Universita' di Napoli "Federico II", Naples, Italy;9Geological Survey of Finland, Espoo, Finland;10Geological Survey of Portugal, Alfragide, Portugal; 11Geological Survey of Sweden, Uppsala, Sweden;12Institute of Geology, Zagreb, Croatia;13Polish Geological Institute, Warsaw, Poland;14Geological Survey of Slovak Republic, Bratislava, Slovak Republic;15Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover, Germany;16Czech Geological Survey, Prague, Czech Republic;17Geological Survey of Spain, Madrid, Spain;18Geological Survey of France, Orléans Cedex, France;19Geological Survey of Austria, Wien, Austria;20Hungarian Geological Institute, Budapest, Hungary;21Centre of Civil Geology, Tirana Albania;22Geological Survey of Estonia, Tallinn, Estonia. The term “floodplain sediment” is synonymouswith “overbank sediment”, “levee sediment”,“vertical accretion deposit” or “alluvial soil”.An arbitrary distinction between overbank andfloodplain sediments was made, however, by Darnley et al. (1995), with respect to the size of the drainage basin, i.e., <100 km2 for overbank sediment and 1000-6000 km2 for floodplainsediment, which in practice was reduced to 500-6000 km2. This classification was subsequentlyfollowed in the FOREGS Geochemical MappingField Manual (Salminen, Tarvainen et al. 1998).The term ‘overbank sediment’ is used for alluvium (clay and silt) accumulated adjacent tolow-order streams (where stream sediment andwater samples were collected in this survey), and ‘floodplain sediment’ to alluvium adjoining high-order drainage channels of typically larger rivers; they are both alluvial sediments, deposited, in low energy environments, from suspension on a floodplain by flood water that cannot be containedwithin the stream channel.From the point of view of geochemicalmapping, overbank sediment samples representsmall drainage basins, which can be used in national geochemical mapping programmes for comparatively detailed regional surveys (Ottesen et al. 2000).  Whereas, floodplain sedimentsamples represent much larger basins, and are a significant sampling medium for continental orglobal scale geochemical mapping, since they arerepresentative of a large area (Xie and Yin 1993, Cheng et al. 1997, Xie and Cheng 1997, 2001,Salminen et al. 2005, Xueqiu 2005).41Floodplain or overbank sediments can be used in the search for new mineral resources, in monitoring environmental change, and also in the prediction of potential environmental hazards. Their effectiveness and suitability in national and continental scale geochemical mapping hasalready been demonstrated by studies firstly in Norway (Ottesen et al. 1989, 2000), andsubsequently in other European countries, during the research work carried out by the Working Group on “Regional Geochemical Mapping” of the Western European Geological Surveys(WEGS) and subsequently FOREGS (Bølviken etal. 1990, 1993, 1996, Demetriades et al. 1990,1993, 1994, Edén and Björklund 1996, De Vos etal. 1996, Hindel et al. 1996, Demetriades and Volden 1997, Pulkkinen and Rissanen 1997, Van der Sluys et al. 1997, Swennen et al. 2000);similar work was carried out in China (Xie andYin 1993, Cheng et al. 1997, Xie and Cheng1997, 2001, Xueqiu 2005).  According to these applied research studies, floodplain or overbanksediment reflects the geochemistry of overburden in the entire upstream river basin, because fine-grained alluvium (silt and clay) is carried insuspension from eroded source materials oververy  long  distances,  and  is  finally  depositedon  the floodplain  in  low   energyenvironments.Interpretation of floodplain sediment results, presented in Part 1 of the Geochemical Atlas of Europe (Salminen et al. 2005), requiredinformation about the geology and mineralisationof the upstream drainage basin, as well asindustrial and urban contaminating activities.  For the geology, regional geological maps of Europe and information were used (Fullard and Darby1962, Kirkaldy 1967, Bederke and Wunderlich1968, Ager 1975, Ziegler 1990, Asch 2003, 2005),and simplified national maps in papers and geochemical atlases (Odehnal 1966, Dunham 1969, Dimitrijevic et al. 1971, Beck-Mannagetta and Matura 1980, Schönenberg and Neugebauer 1987, Koljonen 1992, Slowanska 1997, Reimannet al. 1998, 2003, Jackson 2004, Salminen et al.2004, Dill et al. 2005), and for mineralisation the digital version of the 1:10 000 000 scale map ofthe International Metallogenic Map of Europe(NGU, 2003), the Metallogenetic map of Europe(Laffitte 1968-1970), the Atlas of EconomicMineral Deposits (Dixon 1979), as well as thevolumes of the Mineral deposits of Europe (Bowie et al. 1979,  Dunning et al. 1982, 1989,Dunning and Evans 1986), and relevant nationalinformation on mineralisation (Ribeiro 1979,1990, Béziat and Coulomb 1990, Stolojan and Viland 1991, Faure et al. 2004, Béziat andBornuat 1995, Vozar and Kacer 1996, Bouchot etal. 2005). Some important mineral deposits are shown on Map 15.  A lithological map is beingprepared and can be downloaded from website.An attempt has been made to give the fullest possible interpretation of floodplain sedimentpatterns, using experience from mineralexploration, and that gained from the pilot andresearch projects of the former WEGS and FOREGS Working Group on ‘RegionalGeochemical Mapping’ (Bølviken et al. 1990,1993, 1996, Demetriades et al. 1990).  The reason lies in the fact that floodplain or overbanksediment is one of the most promising samplemedia, which can be used in a cost-effectivemanner to map the geochemistry of the terrestrial surface of our planet under the auspices of the IUGS/IAGC “Global Geochemical Baselines”project.  Also, it can be used to monitorenvironmental change in Europe by setting uppermanent monitoring stations in selected, if not all, large drainage basins. In the description of element distribution in floodplain sediment, as for soil and stream sediment, the following definitions were adopted with reference to the coloured maps andhistograms in Part 1 of the Geochemical Atlas of Europe (Salminen et al. 2005):x Low values group the three lowest shadesof blue in the colour scale, corresponding to values ranging from the minimum up tothe 25th percentile, defined as “very low”and “low background” concentrations in Part 1 (refer to Part 1, Tarvainen et al.2005, p.97).x High values group the three highest shades of red in the colour scale, corresponding to values from the 75th percentile up to themaximum, defined as “high”, “very high”and “highly anomalous” concentrations in Part 1 (Tarvainen et al. 2005, p.97).Correlation coefficients were calculated with Pearson’s product-moment linear correlationmethod (Table available in electronic format onwebsite), after elimination of outliers, andsubsequent pairwise deletion of absent  data. Outliers were defined as values exceeding by a factor of 1.5 other nearby results for a given42element, when all analytical results are ranked. They are generally visible on the histogram accompanying each map in Part 1 of theGeochemical Atlas.  Sometimes outliers differ by a factor of <1.5 among themselves, but a gap of >1.5 on the histogram may appear after a fewvalues (when data are ranked).  A decision was, therefore, taken to remove a maximum of four outliers for the calculation of linear correlation coefficients.  A list of outliers for floodplain sediments is given in Table 6. Throughout the text, the following notation isused for the correlation coefficients: x Very strong correlation:  >0.8x Strong correlation:  between 0.6 and 0.8x Good correlation: between 0.4 and 0.6x Weak correlation: between 0.3 and 0.4AcknowledgementsThe use of overbank or floodplain sediments incontinental scale geochemical mapping would have not been possible if their potential was not foreseen by Professor Bjorn Bølviken, who wasthe Chairman from 1986 to 1993 of the first Working Group on Regional GeochemicalMapping of the Western European GeologicalSurveys (WEGS), and subsequently the Forum of European Geological Surveys (FOREGS).  During the last meeting of the Working Group inHannover, the participating members (Otmar Schermann from Austria, Erwin Decoene from Belgium, Reijo Salminen from Finland, Roland Hindel from Germany, Alecos Demetriades fromGreece, Jim Bogen and Rolf Tore Ottesen fromNorway) signed on the 1st of July 1993 a card, given to Professor Bølviken, with the following dedication:“Bølviken’s Regional Geochemical Mappingof Western Europe towards the Year 2000:  A veryimportant project ahead of its time.  Conceived by a person with extreme foresight and supported by Europeans with different cultures, proving that European unity could be realised as long as people meet and discuss matters openly and with integrity. Thank you for bringing us together and hope that we meet again to complete the ‘dream’”.This 1993 ‘dream’ has now become a reality,and this section is, therefore, dedicated toProfessor Bjørn Bølviken as an acknowledgementof his pioneering role. In the far east, in China, there is anotherpioneer with foresight, Professor Xuejing Xie, who has proven, on the continental scale, thesuitability of floodplain sediment as the most cost-effective sampling medium for globalgeochemical mapping.  We are certain that Professor Bjørn Bølviken would not mind sharing this dedication and acknowledgement withProfessor Xuejing Xie, since floodplain oroverbank sediment may one day be the samplingmedium that will be used for the geochemicalmapping of the globe, our home planet. Finally Dr Clemens Reimann from the Geological Survey of Norway gave valuable comments on this chapter. 43Table 6. Outliers of the floodplain sediment data. Criterion: an outlier has a value exceeding by factor of 1.5 othernearby results, when all analytical results are ranked.  A maximum of four outliers were removed for the calculation oflinear correlation coefficients.Sample Country Element Unit Value Next value FactorN26E14F4 Greece As mg kg-1 390 197 1.98N28W05F1 Portugal Be mg kg-1 47.5N29W05F2 Spain Be mg kg-1 21.81N29W05F3 Spain Be mg kg-1 15.3 10.1 1.51N26E14F4 Greece Cd mg kg-1 23.6 15.2 1.55N26W03F3 Spain Cu mg kg-1 495N33E11F2 Slovakia Cu mg kg-1 495N26W05F1 Portugal Cu mg kg-1 435 267 1.63N44E07F5 Sweden Dy mg kg-1 19.6 12.9 1.52N44E07F5 Sweden Er mg kg-1 12.2 7.29 1.67N36E04F2 Germany Fe2O3 % 35.8N44E07F5 Sweden Fe2O3 % 32.9 10.4 3.17N34W03F2 UK Ga mg kg-1 52.0 29.0 1.79N44E07F5 Sweden Gd mg kg-1 22.6 14.8 1.53N29E07F5 Italy Hg mg kg-1 4.39N33E09F4 Slovakia Hg mg kg-1 3.56 2.19 1.63N44E07F5 Sweden Ho mg kg-1 4.47 2.74 1.63N44E07F5 Sweden Lu mg kg-1 2.21 1.15 1.92N44E07F5 Sweden MnO mg kg-1 6.61 0.99 6.68N40E03F4 Norway Mo mg kg-1 191N44E07F5 Sweden Mo mg kg-1 53.2 6.59 8.08N19W10F1 Spain Nb mg kg-1 125 43.0 2.91N26E14F2 Greece Ni mg kg-1 1 080 N28E11F1 Albania Ni mg kg-1 947 555 1.71N36E04F2 Germany P2O5 % 2.61N36E07F2 Germany P2O5 % 1.63 1.06 1.54N26E14F4 Greece Pb mg kg-1 7 084 N34E03F1 Belgium Pb mg kg-1 3 614N37W01F1 UK Pb mg kg-1 2 075 1 190 1.74N33E11F3 Slovakia Sb mg kg-1 99.4 54.5 1.82N34W02F3 UK Sn mg kg-1 649N28W04F2 Portugal Sn mg kg-1 260N28W05F1 Portugal Sn mg kg-1 238N28W05F4 Portugal Sn mg kg-1 181 118 1.53N27W02F2 Spain Sr mg kg-1 1 661 1 063 1.56N28W05F1 Portugal Ta mg kg-1 38.1N34W03F2 UK Ta mg kg-1 15.1 5.78 2.62N44E07F5 Sweden Tm mg kg-1 1.89 1.08 1.75N44E07F5 Sweden U mg kg-1 89.0 18.0 4.94N28W05F4 Portugal W mg kg-1 123N29W05F3 Spain W mg kg-1 103.8N28W04F2 Portugal W mg kg-1 84.2N35W01F2 UK W mg kg-1 82.2 42.3 1.94N44E07F5 Sweden Y mg kg-1 130.5 56.4 2.31N44E07F5 Sweden Yb mg kg-1 13.0 7.92 1.64N26E14F4 Greece Zn mg kg-1 4 91N34E03F1 Belgium Zn mg kg-1 3 643 1 764 2.0744

Distribution of elements in floodplain sediment

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Distribution of elements in floodplain sediment

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