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Titolo:
GEOCHEMISTRY AND WATER DYNAMICS II - TRACE-METALS AND PB-SR ISOTOPES AS TRACERS OF WATER MOVEMENTS AND EROSION PROCESSES
Autore:
LUCK JM; BENOTHMAN D;
Indirizzi:
UNIV MONTPELLIER 2,UMR CNRS 5569,CASE 057 F-34095 MONTPELLIER FRANCE
Titolo Testata:
Chemical geology
fascicolo: 3-4, volume: 150, anno: 1998,
pagine: 263 - 282
SICI:
0009-2541(1998)150:3-4<263:GAWDI->2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
STABLE LEAD ISOTOPES; RIVER WATER; SUSPENDED LOADS; NORTH-ATLANTIC; MISSISSIPPI RIVER; STREAM WATER; CONGO BASIN; SEDIMENTS; INFERENCES; EVOLUTION;
Keywords:
GEOCHEMISTRY; WATER DYNAMICS; TRACE METALS; PB-SR ISOTOPES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
54
Recensione:
Indirizzi per estratti:
Citazione:
J.M. Luck e D. Benothman, "GEOCHEMISTRY AND WATER DYNAMICS II - TRACE-METALS AND PB-SR ISOTOPES AS TRACERS OF WATER MOVEMENTS AND EROSION PROCESSES", Chemical geology, 150(3-4), 1998, pp. 263-282

Abstract

A dynamic scheme for water movements over a flood in a small watershed was proposed in a previous paper [Ben Othman, D., Luck, J.M., Tournoud, M.G., 1997. Geochemistry and water dynamics: application to short-time scale flood phenomena in a small Mediterranean catchment: I. Alkalis, alkali-earths and Sr isotopes. Chem. Geol. [140] 9-28] based on major, alkali-alkali earth trace elements and Sr isotopes. In the present paper, metal contents and Pb isotope data are reported for the samesamples, and compared to natural and anthropogenic local sources analysed for this purpose. Water treatment plants have stable Pb-206/Pb-201 but show relatively large :Pb-207/Pb-204 variations, presumably related to yet unidentified (industrial? ) Ph sources. Some Cu-Zn-rich chemicals used extensively on vineyards have unradiogenic Pb-206/Pb-204 around 17.7. Local rains sampled over two years show roughly similar lowvalues. Pb from rocks is variable and more radiogenic (Pb-206/Pb-204 approximate to 18.8-22.8). Except for the first hours, trace element concentrations in the dissolved load are similar to or slightly higher than those observed over the year, and similar to other moderately anthropogenic areas [Shiller, A.M., Boyle, E.A., 1987. Variability of dissolved trace metals in the Mississippi river. Geochim. Cosmochim. Acta[51] 3273-3277] for [Pb] (0.05-0.45 nM), [Zn] (10-75 nM) and [Cd] (0.03-0.18 nM). Dissolved [U] and [Co] show simple variations correlated to carbonate, related to local natural sources. Mosi trace elements inthe particulate load are strongly correlated. Lead isotopes in the dissolved and particulate loads show ranges over the flood, again similar to those observed over the year (Pb-206/Pb-204 approximate to 17.9-18.3), implying the same sources. The very good alignments observed in Pb-207/Pb-204 and Pb-208/Pb-204 vs. Pb-206/Pb-204 diagrams, especiallyfor the particulate, are interpreted as mixing phenomena. Generally Pb isotopic signature of the dissolved load is less radiogenic than theparticulate, indicating differences in sources or proportions and absence of isotopic equilibration with respect to the time of transfer. Pb isotopes shift regularly with time away from the road runoff endmember towards more radiogenic values. The strong negative correlation between Pb isotopes in the particulate load and Sr isotopes in the dissolved load, observed for the first time in a small watershed, probably reflects the local coupling between mechanical and chemical erosion, respectively. (C) 1998 Elsevier Science B.V. All rights reserved.

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Documento generato il 15/07/20 alle ore 08:24:56