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  • 1
    Publikationsdatum: 2017-04-04
    Beschreibung: Venere Lake, in the Pantelleria Island thermal system (Central Mediterranean Sea) consists of a mix of seawater and hydrothermal volcanic fluids containing high levels of dissolved SiO2. Close to the lake's thermal springs, siliceous stromatolites are deposed under high bacterial activity conditions whereas roughly interlaminated Ca-carbonates and microbial mats are widely scattered in the lake. The dissolved REE speciation in lake waters is dominated by [REE(CO3)2]−, [REE(CO3)]+ and [REE(H3SiO4)]2+ complexes. On the contrary the most abundant Zr and Hf species are hydroxyl- and fluoride-complexes. The behavior of REE Zr and Hf in the Venere lake waters is controlled by precipitation of amorphous silica, carbonates and bacterial activity. Chondritenormalized REE patterns in stromatolites are characterized by positive La anomalies, superchondritic Y/Ho ratios and negative Eu anomalies. The Eu depletion is also found in microbial mats where is associated to a “chondritic” Y/Ho signature. Zr and Hf differently behave in dissolved phase and in newly-formed siliceous and carbonatic material: Hf reacts easily into amorphous silica surfaces whereas Zr is preferentially partitioned onto phosphate binding sites on microbial cell surfaces similar to the observed behavior of heavy REE (HREE).Wesuggest that the Zr-Hf relationship reflect the interface processes between mineral phases and bacterial membranes or compounds produced by bacterial activity.
    Beschreibung: Published
    Beschreibung: 209-215
    Beschreibung: 4V. Vulcani e ambiente
    Beschreibung: JCR Journal
    Beschreibung: restricted
    Schlagwort(e): Rare Earth Elements, Zr/Hf ratio, Silica-stromatolites, Pantelleria Island ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Publikationsdatum: 2017-04-04
    Beschreibung: Hydrothermal lakes are a very common feature in volcanic environments, and among these lake Specchio di Venere (Pantelleria island, Italy) has attracted the interest of several researchers due to its peculiar characteristics. With the aim of improving the knowledge of its mineralogy, our work pointed out the characterisation of the bottom lake sediments. We collected and analysed 5 sediments cores around the shoreline, determining the mineralogical phases, concentration of major, minor, and trace elements, and the isotopic composition of carbon and oxygen in the carbonate phases. Our findings remarked a general compositional homogeneity in both the vertical and horizontal distribution of mineral phases, with the exception of peculiar geological niches connoted by biological and hydrothermal activities.
    Beschreibung: Published
    Beschreibung: ID 8414581
    Beschreibung: 4V. Vulcani e ambiente
    Beschreibung: JCR Journal
    Beschreibung: open
    Schlagwort(e): Pantelleria ; Sediments ; Geochemistry ; 04. Solid Earth::04.04. Geology::04.04.08. Sediments: dating, processes, transport
    Repository-Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Materialart: article
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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