Hydrothermal nontronite formation at Eolo Seamount (Aeolian volcanic arc, Tyrrhenian Sea) (Articolo in rivista)

Type
Label
  • Hydrothermal nontronite formation at Eolo Seamount (Aeolian volcanic arc, Tyrrhenian Sea) (Articolo in rivista) (literal)
Anno
  • 2007-01-01T00:00:00+01:00 (literal)
Alternative label
  • Dekov V.M. (a), Kamenov G.D. (b), Stummeyer J. (c), Thiry M. (d), Savelli C. (e), Shanks W.C. (f), Fortin D. (g), Kuzmann E. (h), Vertes, A. (h) (2007)
    Hydrothermal nontronite formation at Eolo Seamount (Aeolian volcanic arc, Tyrrhenian Sea)
    in Chemical geology
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Dekov V.M. (a), Kamenov G.D. (b), Stummeyer J. (c), Thiry M. (d), Savelli C. (e), Shanks W.C. (f), Fortin D. (g), Kuzmann E. (h), Vertes, A. (h) (literal)
Pagina inizio
  • 103 (literal)
Pagina fine
  • 119 (literal)
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  • DOI 10.1016/j.chemgeo.2007.08.006 (literal)
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  • 245 (literal)
Rivista
Note
  • ISI Web of Science (WOS) (literal)
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  • (a) Department of Geology and Paleontology, University of Sofia, 15 Tzar Osvoboditel Blvd., 1000 Sofia, Bulgaria (b) Department of Geological Sciences, University of Florida, 241 Willamson Hall, Gainesville, FL 32611, USA (c) Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, D-30655 Hannover, Germany (d) Centre d'Informatique Geologique, Ecole des Mines de Paris, 35 rue St. Honore, 77305 Fontainebleau, France (e) Istituto di Geologia Marina, CNR, Via Gobetti 101, 40129 Bologna, Italy (f) U.S. Geological Survey, 973 Denver Federal Center, Denver, CO 80225, USA (g) Department of Earth Sciences, University of Ottawa, 140 Louis Pasteur, Ottawa, Canada K1N 6N5 (h) Laboratory of Nuclear Chemistry, Hungarian Academy of Sciences Chemical Research Center, Eötvös University, 1/A Pázmány P., Budapest H-1117, Hungary (literal)
Titolo
  • Hydrothermal nontronite formation at Eolo Seamount (Aeolian volcanic arc, Tyrrhenian Sea) (literal)
Abstract
  • A sediment core containing a yellowish-green clay bed was recovered from an area of extensive hydrothermal deposition at the SE slope of the Eolo Seamount, Tyrrhenian Sea. The clay bed is composed of pure nontronite (described for the first time in the Tyrrhenian Sea), which appears to be the most aluminous nontronite ever found among the seafloor hydrothermal deposits. The high Al content suggests precipitation from Al-containing hydrothermal solutions. The REE distribution of the Eolo nontronite has a V-shape pattern. The heavy REE enrichment is in part due to their preferential partitioning in the nontronite structure. This enrichment was possibly further enhanced by the HREE preferential sorption on bacterial cell walls. The light REE enrichment is the result of scavenging uptake by one of the nontronite precursors, i.e., poorly-ordered Fe-oxyhydroxides, from the hydrothermal fluids. Oxygen isotopic composition of the nontronite yields a formation temperature of 30 T, consistent with a low-temperature hydrothermal origin. The relatively radiogenic Nd isotopic signature of the nontronite compared to the present-day Mediterranean seawater indicates that approximately half of Nd, and presumably the rest of the LREE, are derived from local volcanic sources. On the other hand, Sr-87/Sr-86 is dominated by present-day seawater Sr. Scanning electron microscopy investigation revealed that the nontronite is composed of aggregates of lepispheres and tube-like filaments, which are indicative of bacteria assisted precipitation. Bacteria inhabiting this hydrothermal site likely acted as reactive geochemical surfaces on which poorly-ordered hydrothermal Fe-oxyhydroxides and silica precipitated. Upon aging, the interactions of these primary hydrothermal precipitates coating bacterial filaments and cell walls likely led to the formation of nontronite. Finally, the well-balanced interlayer and layer charges of the crystal lattice of seafloor hydrothermal nontronite decrease its sorption capacity to zero. Thus the ubiquitous nontronite precipitation along the active plate boundaries and around the hot spots has no significant impact on oceanic trace element chemistry. (literal)
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