0000000000464722
AUTHOR
M. Raso
Geochemistry of Zr, Hf, and REE in a wide spectrum of Eh and water composition: The case of Dead Sea Fault system (Israel)
International audience; Along the Jordan Valley-Dead Sea Fault area several natural waters in springs, wells, and catchments occur. The chemical-physical characters of the studied waters allowed for the first time the investigation of the Zr and Hf geochemical behavior, apart from REE, extended to a wide range of Eh, temperature, salinity, and pH conditions. The results of this study indicate that the dissolved Zr and Hf distribution in natural waters is strongly influenced by redox conditions since these in turn drive the deposition of Fe-oxyhydroxides or pyrite. In oxidizing waters saturated or oversaturated in Fe-oxyhydroxides (Group 1), superchondritic Zr/Hf values are measured. On the …
Authigenic phases and biomass contents drive Zr, Hf and REE distributions in anoxic lake sediments.
Abstract. REE, Zr and Hf distributions in seafloor sediments collected from the hypersaline, anoxic Thetis, Kryos, Medee and Tyro deep-sea basins from the Eastern Mediterranean were determined in light of their mineralogical composition, and biomass contents. Mineralogical investigations demonstrate that all the studied sediments show a similar mineralogy. Detritic assemblages mainly consist of quartz, gypsum and calcite with Mg contents ranging from 0 to about 7%, often of a bioclastic nature. On the contrary, authigenic parageneses are formed by halite, bischofite, dolomite and calcite, with Mg contents up to 22%. Textural evidences of biological activity were also identified. In sediment…
Lo stato dell’ambiente marino nell’area del Canale di Sicilia in prossimità del SIN di Gela.
Viene illustrata in questa nota l’attuale condizione in cui si trova lo stato dell’ambiente marino nell’area del Canale di Sicilia immediatamente a ridosso della costa merdionale delle Sicilia dal Golfo di Gela alla costa iblea. Lo stato dell’ambiente in oggetto viene valutato in base alla distribuzione di alcuni metalli in tracce normalmente ritenuti fra i più significativi per gli scopi prefissati, esaminati lungo la colonna d’acqua e nei sedimenti superficiali di fondale. I risultati ottenuti, illustrati anche attraverso un’indagine statistica multivariata, indicano un arricchimento superficiale della colonna d’acqua in lantanio che può essere ascritto tanto ad un’origine litogenica, qua…