The Monte Guardia rhyolitic eruption (~22 ka, Lipari, Aeolian Islands, Italy) produced a sequence... more The Monte Guardia rhyolitic eruption (~22 ka, Lipari, Aeolian Islands, Italy) produced a sequence of pyroclastic deposits followed by the emplacement of lava domes. The total volume of dense magma erupted was nearly 0.5 km 3. The juvenile clasts in the pyroclastic deposits display a variety of magma mixing evidence (mafic magmatic enclaves, streaky pumices, mineral disequilibria and heterogeneous glass composition). Petrographic, mineralogical and geochemical investigations and melt inclusion studies were carried out on the juvenile clasts in order to reconstruct the mixing process and to assess the pre-eruptive chemico-physical magmatic conditions. The results suggest that the different mingling and mixing textures were generated during a single mixing event between a latitic and a rhyolitic end member. A denser, mixed magma was first erupted, followed by a larger volume of an unmixed, lighter rhyolitic one. This compositional sequence is the reverse of what would be expected from the tapping of a zoned magma chamber. The Monte Guardia rhyolitic magma, stored below 200 MPa, was volatile-rich and fluid-saturated, or very close to this, despite its relatively low explosivity. In contrast to previous interpretations, there exists the possibility that the rhyolite could rise and erupt without the trigger of a mafic input. The entire data collected are compatible with two possible mechanisms that would generate a reversely zoned sequence: (1) the occurrence of thermal instabilities in a density stratified, salic to mafic magma chamber and (2) the intrusion of rising rhyolite into a shallower mafic sill/dike.
Magmatism accompanies rifting along divergent plate boundaries, although its role before continen... more Magmatism accompanies rifting along divergent plate boundaries, although its role before continental breakup remains poorly understood. For example, the magma-assisted Northern Main Ethiopian Rift (NMER) lacks current volcanism and clear tectono-magmatic relationships with its contiguous rift portions. Here we define its magmatic behaviour, identifying the most recent eruptive fissures (EF) whose aphyric basalts have a higher Ti content than those of older monogenetic scoria cones (MSC), which are porphyritic and plagioclase-dominated. Despite the similar parental melt, EF and MSC magmas underwent different evolutionary processes. While MSC magmas were stored at intermediate crustal levels, EF magmas rose directly from the Moho without contamination, even below older polygenetic volcanoes, suggesting rapid propagation of transcrustal dikes across solidified magma chambers. Whether this recent condition in the NMER is stable or transient, it highlights a transition from central polygenetic to linear fissure volcanism, indicative of increased tensile conditions and volcanism directly fed from the Moho, suggesting transition towards mature rifting.
Magmatism accompanies rifting along divergent plate boundaries, although its role before continen... more Magmatism accompanies rifting along divergent plate boundaries, although its role before continental breakup remains poorly understood. For example, the magma-assisted Northern Main Ethiopian Rift (NMER) lacks current volcanism and clear tectono-magmatic relationships with its contiguous rift portions. Here we define its magmatic behaviour, identifying the most recent eruptive fissures (EF) whose aphyric basalts have a higher Ti content than those of older monogenetic scoria cones (MSC), which are porphyritic and plagioclase-dominated. Despite these differences, calculations highlight a similar parental melt for EF and MSC products, suggesting only a different evolutionary history after melt generation. While MSC magmas underwent a further step of storage at intermediate crustal levels, EF magmas rose directly from the base of the crust without contamination, even below older polygenetic volcanoes, suggesting rapid propagation of transcrustal dikes across solidified magma chambers. ...
Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine ... more Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine the effects of multiple source lithology, climate, weathering, transport and depositional environment on epiclastic sand composition. Volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the Gazzi–Dickinson method, and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using GIS. Several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized, and divided into two categories of provenance lithotypes: lavas and pyroclastic rocks ranging in composition from basaltic andesitic, to andesitic, to rhyolitic. Volcanic lithic fragments from Lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork, felsitic, vitric and microlitic textures. Moreover, high amounts of detrital less durable mi...
Archives of Environmental Contamination and Toxicology, 2015
Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months at 32 sites located i... more Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months at 32 sites located in and around an industrial area of S Italy whose main anthropogenic sources of atmospheric trace elements are a biomass power plant and vehicular emissions. Meteorological stations were deployed at four sites for finer detection of local wind patterns. The station near the biomass power plant showed a significant S-SE wind component not detectable by measurements made at the regional scale or by the other local meteorological stations. Sb, Sn, and Mo showed a very high degree of covariance and a statistically significant correlation with traffic rate. No element concentrations in the exposed thalli were correlated with distance from the biomass power plant, although Ti and Co
This study was carried out in a river catchment in southern Italy to determine some possible rela... more This study was carried out in a river catchment in southern Italy to determine some possible relationships between the distribution of chemical elements and size fractions in stream sediments. Through the presence of variations in concentration of some elements in each size fraction, it was possible to examine the influence of particle-size on geochemical distribution of stream sediments. From this point of view, it is very useful to study the Lese river catchment because it is representative of the whole Mediterranean area given its characteristics, which are common to other similar areas. Sediment samples were collected from 13 stations in the catchment area. The chemical compositions of bulk samples coupled with those of some selected particle size fractions were analyzed for 25 elements by using X-ray fluorescence spectrometry and for their sedimentological characteristics. Particle-size analysis was focused on trying to understand how samples from the same site showed different geochemical distribution in the different size fractions. Stream sediments in the study area consist mostly of sand particles. Chemical analyses were performed to determine to what extent the stream sediments retain the geochemical signature of their parent rocks. Some size fractions, and not only the recommended < 150 µm, allowed testing of the validity of FOREGS procedures, which considers the < 150 µm to be the optimum fraction for chemical analysis. The elemental values were analyzed according to the various thresholds imposed by Italian legislative Decree No. 152/2006. This study suggests that the geochemistry of stream sediments also needs to be characterized in order to evaluate the potential chemical pollution of an area.
In this work are shown preliminary results about a tephrostratigraphic study carried out in marin... more In this work are shown preliminary results about a tephrostratigraphic study carried out in marine cores sampled in Ionian and Tyrrhenian seas. Twelve gravity cores were collected offshore the eastern margin of southern Tyrrhenian coast and the Taranto Gulf in the Ionian Sea during a cruise of the R/V Urania (sponsored by CNR of Italy). The cores were drilled at water depths between 76m (CD02) and 995m (GT2) and are between 0,80 to 5,30 m long. The sampled hemipelagic deposits contains several cryptotephras and, at present, five cores were sampled for tephra layers: GT2 and GT4 (Taranto Gulf), D1 and P1 (Policastro Gulf) and GS1 (Salerno Bay). EDS analyses were carried out on fresh volcanic glasses and mineral phases at Dipartimento di Scienze della Terra of University of Pisa and at Dipartimento di Biologia, Ecologia e Scienze della Terra of University of Calabria. Chemical compositions of deposits were compared with those of the main Holocene eruptions of Campanian volcanoes and M...
Journal of Volcanology and Geothermal Research, 2011
The Lami succession piled up during the explosive activity of the Monte Pilato on Lipari Island (... more The Lami succession piled up during the explosive activity of the Monte Pilato on Lipari Island (Central Aeolian Arc, Italy). It comprises a repetitive alternation of fall and pyroclastic density current beds, which define 13 Units separated by fine ash beds. Despite the homogeneous rhyolitic composition the juveniles fragments show strong textural heterogeneities from highly vesicular pumice to dense black obsidians. The pumice types are termed: i) "tube", which shows elongated tubular vesicles, ii) "frothy", highly vesicular with large, sub-rounded vesicles, and iii) agglomerated and welded. Two types of obsidian pyroclasts are recognized: i) aphyric black obsidian, and ii) grey obsidian showing spherulitic texture. All these pyroclastic types occur throughout the stratigraphic succession, and mixed in the same bed. They account for changing physical conditions along the conduit, which is hypothesised to be filled by a melt plug during the eruption of 12 out of 13 Units. The strong textural heterogeneities of the juvenile fragments testify for the existence of differential shear rates, which can be explained though two shear mechanism: i) simple shear, producing horizontal zonation of texture in the conduit with black obsidians along the conduit walls passing to tube and frothy pumice to the centre, and ii) pure shear, producing a vertical zonation in the conduit, with black obsidians at the top overlying frothy pumice. Agglomerated and welded pumice of Unit 13 is thought to represent the portion of magma heated by a batch of hotter melt that entered the magma chamber and triggered the eruption. The deposits of Unit 13 represent a unique case of spatter accretion due to accumulation of hot, low-viscous rhyolitic pumice fragments, emplaced from pyroclastic fountaining.
Journal of Mineralogical and Petrological Sciences, 2013
Viscosity changes during the crystallization of a shoshonitic lava from the Vulcanello peninsula ... more Viscosity changes during the crystallization of a shoshonitic lava from the Vulcanello peninsula (Aeolian Islands, southern Tyrrhenian Sea, Italy) were measured by use of a electromagnetic rotational viscometer under Ni-NiO buffered conditions at temperatures ranging from 1539 K to 1381 K. Results showed an increase in effective viscosity from 131 Pa s to 15320 Pa s as the crystal content increased from 0 vol% to ~ 14 vol%. The crystallization processes in the nominally dry shoshonite began at 1420 K with the formation of clinopyroxene, which was followed by the formation of plagioclase and olivine at 1401 K. Experimental observations differed from predictions derived from the use of the Einstein-Roscoe equation with the Marsh (E-R-M) parameter at crystal contents higher than 8 vol%. The relative viscosity of samples was larger than that calculated by E-R-M by a factor of up to 9.5 as the temperature decreased to 1381 K. The large departure of the experimental results from the E-R-M equation predictions was likely caused by the interaction of elongated pyroxene crystals. The measured viscosity data were used to estimate the potential for emplacement of shoshonitic lavas.
Soils can exhibit a complex range of physical, mineralogical, and chemical features depending on ... more Soils can exhibit a complex range of physical, mineralogical, and chemical features depending on many interrelated factors such as parental rock composition and mineralogy, climate, topography, vegetation amounts and types, water infiltration versus runoff, soil moisture, organic matter, presence and types of anthropogenic contaminants, and many others. Radioactivity as measured on these complex systems is consequently perturbed by several mixed effects. In order to find out a possible (potential) relationship among soil properties and experimental data attributable to radioactivities of K, Th, U and Rn a detailed investigation has been performed in the Cecita Lake basin (Sila Grande, Calabria, Southern Italy). Most of the soil types outcropping in the Cecita Lake surroundings belong to the Entisol and Inceptisol orders [USDA (United States Department of Agriculture), 2006. Keys to Soil Taxonomy. 10th edit., USDA, Soil Survey Staff, Natural Resources Conservation Service, Washington D.C., 333 pp.], representing relatively young, poorly to moderately differentiated soils, showing features strongly dependent on the nature of the parent rock and the climatic conditions. Disintegrations contributed by K, Th, U and Rn measured respectively in % (K), ppm (U and Th) and kBq/m 3 (Rn), have been related to 13 a priori known soil unit groups with well-defined general features and spatial position. The data have been analysed by using graphical and numerical statistical procedures able to manage compositional data in a correct sample space. The paper summarises the results of this research and highlights the conclusions drawn from these investigations, particularly concerning i) the modelling of the high U variability, a behaviour that tends to homogenise the differences potentially attributable to soil features, with the exception of situations where uranium could be enriched due to adsorption onto iron oxi-hydroxides and/or clay minerals or concentrated in argillic horizons due to illuviation; ii) the discovering of the discriminative effect of the K/Th ratio values, particularly for soil groups where Th behaviour, as other tetravalent actinides, is strongly affected by the presence of mineral colloids or where the presence of clays affects the trapping of K; iii) the clustering of the a priori known soil groups in four new sets characterised by internal similarities for Rn values for which the morphology appears to be the most important discriminative effect.
Journal of Volcanology and Geothermal Research, 2008
This paper focuses on the main morphological, physical, chemical and mineralogical features of an... more This paper focuses on the main morphological, physical, chemical and mineralogical features of an andic-like soil, widely outcropping in the Sila upland plateau of Calabria (southern Italy), and its potential role in tephrostratigraphy. A multidisciplinary and multiscale ...
Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine ... more Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine the effects of multiple source lithology, climate, weathering, transport and depositional environment on epiclastic sand composition. Volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the Gazzi–Dickinson method, and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using GIS. Several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized, and divided into two categories of provenance lithotypes: lavas and pyroclastic rocks ranging in composition from basaltic andesitic, to andesitic, to rhyolitic. Volcanic lithic fragments from Lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork, felsitic, vitric and microlitic textures. Moreover, high amounts of detrital less durable mi...
&lt;p&gt;Geogenic Cr(VI) contamination is a worldwide environmental issue which mainly oc... more &lt;p&gt;Geogenic Cr(VI) contamination is a worldwide environmental issue which mainly occurs in areas where ophiolitic rocks crop out. In these areas Cr (VI) can reach high concentrations into groundwaters becoming highly dangerous for human health. Indeed Cr(VI) is recognized as highly toxic element with high mobility and bioavailability [1]. Due to these features, starting from July 2017, Italian government has lowered the Cr(VI) limit value for drinking water to 10 &amp;#181;g/L. To improve the living standards in contaminated areas, it is needed (i) to understand the release and fate of contaminant during the water-rock interaction and (ii) to develop efficient remediation systems for natural polluted waters. In this regard, a complementary study on genesis and treatment of a Cr-rich groundwater coming from Italian ophiolitic aquifers was conducted. Reaction path modelling is a proven geochemical tool to understand the release of Cr and its oxidation from Cr(III) to Cr(VI) during the water-rock interaction. The generally accepted hypothesis of scientific community is that geogenic Cr(III) oxidation&amp;#160; is driven by the reduction of trivalent and tetravalent manganese (Mn(III); Mn (IV)) [2] whereas in this work the role of trivalent Fe hosted in serpentine minerals was re-evaluated. Unlike Mn, Fe is the main oxidant present in suitable amount in these rocks. Literature data confirmed the presence of Fe(III) into serpentine minerals hence reaction path modelling was performed varying the Fe (III)/Fe(tot) ratio ranging&amp;#160; from 0.60 to 1.00. The theoretical paths, reproduce the analytical concentrations of relevant solutes, including Cr(VI), in the Mg-HCO&lt;sub&gt;3&lt;/sub&gt; water type hosted in the ophiolitic aquifers of Italy [3]. With increasing of Fe(III)/Fe(tot) ratio in serpentine minerals, high Cr(VI) concentration hold into solution until high alkalinity values. In addition, the spring with the highest Cr(VI) content (75 &amp;#181;g/L) was treated to lower its concentration below the threshold values. &amp;#160;In this work membrane technologies were used as&amp;#160; innovative method considering their many benefits, like the improvement of product quality without using chemicals [4]. A laboratory-scale set-up was used to carry out both Nanofiltration (NF) and Reverse Osmosis (RO) experiments. The experiments were conducted on different commercial membranes: one NF membrane module named DK (polyamide) and two RO membrane modules named AD (polyamide) and CD (cellulose).Tests were performed varying the operating pressures, and high Cr(VI) rejections (around 95%) were reached for all tested membranes, leading to a water containing Cr(VI) in concentrations below the threshold limits. The high flux, obtained already at lower operating pressures (27 L/m&lt;sup&gt;2&lt;/sup&gt;h-10bar), combined with high selectivity towards Cr(VI) makes NF a favorable remediation option. The results obtained in this work are in line with the few data available in the literature for natural contaminated waters and there are quite promising for future scientific developments and application.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;References&lt;/p&gt; &lt;p&gt;[1]Marinho B. A. et al., 2019. Environ Sci Pollut Res,&amp;#160;26(3), 2203-2227&lt;/p&gt; &lt;p&gt;[2]Oze C. et al., 2007. Proc. Natl. Acad. Sci. 104, 6544&amp;#8211;6549&lt;/p&gt; &lt;p&gt;[3]Apollaro C. et al., 2019. Sci. Total Environ. 660, 1459-1471&lt;/p&gt; &lt;p&gt;[4]Figoli &amp;#160;A. &amp; Criscuoli &amp;#160;A., 2017. Springer (Singapore); ISBN:9789811056215&lt;/p&gt;
An innovative methodological approach is proposed in this study, based on the chemical analysis o... more An innovative methodological approach is proposed in this study, based on the chemical analysis of different portions of soil horizons (illuvial pedofeatures, pedogenic matrix and skeletal parent rock fragments) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-...
The Monte Guardia rhyolitic eruption (~22 ka, Lipari, Aeolian Islands, Italy) produced a sequence... more The Monte Guardia rhyolitic eruption (~22 ka, Lipari, Aeolian Islands, Italy) produced a sequence of pyroclastic deposits followed by the emplacement of lava domes. The total volume of dense magma erupted was nearly 0.5 km 3. The juvenile clasts in the pyroclastic deposits display a variety of magma mixing evidence (mafic magmatic enclaves, streaky pumices, mineral disequilibria and heterogeneous glass composition). Petrographic, mineralogical and geochemical investigations and melt inclusion studies were carried out on the juvenile clasts in order to reconstruct the mixing process and to assess the pre-eruptive chemico-physical magmatic conditions. The results suggest that the different mingling and mixing textures were generated during a single mixing event between a latitic and a rhyolitic end member. A denser, mixed magma was first erupted, followed by a larger volume of an unmixed, lighter rhyolitic one. This compositional sequence is the reverse of what would be expected from the tapping of a zoned magma chamber. The Monte Guardia rhyolitic magma, stored below 200 MPa, was volatile-rich and fluid-saturated, or very close to this, despite its relatively low explosivity. In contrast to previous interpretations, there exists the possibility that the rhyolite could rise and erupt without the trigger of a mafic input. The entire data collected are compatible with two possible mechanisms that would generate a reversely zoned sequence: (1) the occurrence of thermal instabilities in a density stratified, salic to mafic magma chamber and (2) the intrusion of rising rhyolite into a shallower mafic sill/dike.
Magmatism accompanies rifting along divergent plate boundaries, although its role before continen... more Magmatism accompanies rifting along divergent plate boundaries, although its role before continental breakup remains poorly understood. For example, the magma-assisted Northern Main Ethiopian Rift (NMER) lacks current volcanism and clear tectono-magmatic relationships with its contiguous rift portions. Here we define its magmatic behaviour, identifying the most recent eruptive fissures (EF) whose aphyric basalts have a higher Ti content than those of older monogenetic scoria cones (MSC), which are porphyritic and plagioclase-dominated. Despite the similar parental melt, EF and MSC magmas underwent different evolutionary processes. While MSC magmas were stored at intermediate crustal levels, EF magmas rose directly from the Moho without contamination, even below older polygenetic volcanoes, suggesting rapid propagation of transcrustal dikes across solidified magma chambers. Whether this recent condition in the NMER is stable or transient, it highlights a transition from central polygenetic to linear fissure volcanism, indicative of increased tensile conditions and volcanism directly fed from the Moho, suggesting transition towards mature rifting.
Magmatism accompanies rifting along divergent plate boundaries, although its role before continen... more Magmatism accompanies rifting along divergent plate boundaries, although its role before continental breakup remains poorly understood. For example, the magma-assisted Northern Main Ethiopian Rift (NMER) lacks current volcanism and clear tectono-magmatic relationships with its contiguous rift portions. Here we define its magmatic behaviour, identifying the most recent eruptive fissures (EF) whose aphyric basalts have a higher Ti content than those of older monogenetic scoria cones (MSC), which are porphyritic and plagioclase-dominated. Despite these differences, calculations highlight a similar parental melt for EF and MSC products, suggesting only a different evolutionary history after melt generation. While MSC magmas underwent a further step of storage at intermediate crustal levels, EF magmas rose directly from the base of the crust without contamination, even below older polygenetic volcanoes, suggesting rapid propagation of transcrustal dikes across solidified magma chambers. ...
Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine ... more Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine the effects of multiple source lithology, climate, weathering, transport and depositional environment on epiclastic sand composition. Volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the Gazzi–Dickinson method, and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using GIS. Several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized, and divided into two categories of provenance lithotypes: lavas and pyroclastic rocks ranging in composition from basaltic andesitic, to andesitic, to rhyolitic. Volcanic lithic fragments from Lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork, felsitic, vitric and microlitic textures. Moreover, high amounts of detrital less durable mi...
Archives of Environmental Contamination and Toxicology, 2015
Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months at 32 sites located i... more Thalli of the lichen Pseudevernia furfuracea were transplanted for 3 months at 32 sites located in and around an industrial area of S Italy whose main anthropogenic sources of atmospheric trace elements are a biomass power plant and vehicular emissions. Meteorological stations were deployed at four sites for finer detection of local wind patterns. The station near the biomass power plant showed a significant S-SE wind component not detectable by measurements made at the regional scale or by the other local meteorological stations. Sb, Sn, and Mo showed a very high degree of covariance and a statistically significant correlation with traffic rate. No element concentrations in the exposed thalli were correlated with distance from the biomass power plant, although Ti and Co
This study was carried out in a river catchment in southern Italy to determine some possible rela... more This study was carried out in a river catchment in southern Italy to determine some possible relationships between the distribution of chemical elements and size fractions in stream sediments. Through the presence of variations in concentration of some elements in each size fraction, it was possible to examine the influence of particle-size on geochemical distribution of stream sediments. From this point of view, it is very useful to study the Lese river catchment because it is representative of the whole Mediterranean area given its characteristics, which are common to other similar areas. Sediment samples were collected from 13 stations in the catchment area. The chemical compositions of bulk samples coupled with those of some selected particle size fractions were analyzed for 25 elements by using X-ray fluorescence spectrometry and for their sedimentological characteristics. Particle-size analysis was focused on trying to understand how samples from the same site showed different geochemical distribution in the different size fractions. Stream sediments in the study area consist mostly of sand particles. Chemical analyses were performed to determine to what extent the stream sediments retain the geochemical signature of their parent rocks. Some size fractions, and not only the recommended < 150 µm, allowed testing of the validity of FOREGS procedures, which considers the < 150 µm to be the optimum fraction for chemical analysis. The elemental values were analyzed according to the various thresholds imposed by Italian legislative Decree No. 152/2006. This study suggests that the geochemistry of stream sediments also needs to be characterized in order to evaluate the potential chemical pollution of an area.
In this work are shown preliminary results about a tephrostratigraphic study carried out in marin... more In this work are shown preliminary results about a tephrostratigraphic study carried out in marine cores sampled in Ionian and Tyrrhenian seas. Twelve gravity cores were collected offshore the eastern margin of southern Tyrrhenian coast and the Taranto Gulf in the Ionian Sea during a cruise of the R/V Urania (sponsored by CNR of Italy). The cores were drilled at water depths between 76m (CD02) and 995m (GT2) and are between 0,80 to 5,30 m long. The sampled hemipelagic deposits contains several cryptotephras and, at present, five cores were sampled for tephra layers: GT2 and GT4 (Taranto Gulf), D1 and P1 (Policastro Gulf) and GS1 (Salerno Bay). EDS analyses were carried out on fresh volcanic glasses and mineral phases at Dipartimento di Scienze della Terra of University of Pisa and at Dipartimento di Biologia, Ecologia e Scienze della Terra of University of Calabria. Chemical compositions of deposits were compared with those of the main Holocene eruptions of Campanian volcanoes and M...
Journal of Volcanology and Geothermal Research, 2011
The Lami succession piled up during the explosive activity of the Monte Pilato on Lipari Island (... more The Lami succession piled up during the explosive activity of the Monte Pilato on Lipari Island (Central Aeolian Arc, Italy). It comprises a repetitive alternation of fall and pyroclastic density current beds, which define 13 Units separated by fine ash beds. Despite the homogeneous rhyolitic composition the juveniles fragments show strong textural heterogeneities from highly vesicular pumice to dense black obsidians. The pumice types are termed: i) "tube", which shows elongated tubular vesicles, ii) "frothy", highly vesicular with large, sub-rounded vesicles, and iii) agglomerated and welded. Two types of obsidian pyroclasts are recognized: i) aphyric black obsidian, and ii) grey obsidian showing spherulitic texture. All these pyroclastic types occur throughout the stratigraphic succession, and mixed in the same bed. They account for changing physical conditions along the conduit, which is hypothesised to be filled by a melt plug during the eruption of 12 out of 13 Units. The strong textural heterogeneities of the juvenile fragments testify for the existence of differential shear rates, which can be explained though two shear mechanism: i) simple shear, producing horizontal zonation of texture in the conduit with black obsidians along the conduit walls passing to tube and frothy pumice to the centre, and ii) pure shear, producing a vertical zonation in the conduit, with black obsidians at the top overlying frothy pumice. Agglomerated and welded pumice of Unit 13 is thought to represent the portion of magma heated by a batch of hotter melt that entered the magma chamber and triggered the eruption. The deposits of Unit 13 represent a unique case of spatter accretion due to accumulation of hot, low-viscous rhyolitic pumice fragments, emplaced from pyroclastic fountaining.
Journal of Mineralogical and Petrological Sciences, 2013
Viscosity changes during the crystallization of a shoshonitic lava from the Vulcanello peninsula ... more Viscosity changes during the crystallization of a shoshonitic lava from the Vulcanello peninsula (Aeolian Islands, southern Tyrrhenian Sea, Italy) were measured by use of a electromagnetic rotational viscometer under Ni-NiO buffered conditions at temperatures ranging from 1539 K to 1381 K. Results showed an increase in effective viscosity from 131 Pa s to 15320 Pa s as the crystal content increased from 0 vol% to ~ 14 vol%. The crystallization processes in the nominally dry shoshonite began at 1420 K with the formation of clinopyroxene, which was followed by the formation of plagioclase and olivine at 1401 K. Experimental observations differed from predictions derived from the use of the Einstein-Roscoe equation with the Marsh (E-R-M) parameter at crystal contents higher than 8 vol%. The relative viscosity of samples was larger than that calculated by E-R-M by a factor of up to 9.5 as the temperature decreased to 1381 K. The large departure of the experimental results from the E-R-M equation predictions was likely caused by the interaction of elongated pyroxene crystals. The measured viscosity data were used to estimate the potential for emplacement of shoshonitic lavas.
Soils can exhibit a complex range of physical, mineralogical, and chemical features depending on ... more Soils can exhibit a complex range of physical, mineralogical, and chemical features depending on many interrelated factors such as parental rock composition and mineralogy, climate, topography, vegetation amounts and types, water infiltration versus runoff, soil moisture, organic matter, presence and types of anthropogenic contaminants, and many others. Radioactivity as measured on these complex systems is consequently perturbed by several mixed effects. In order to find out a possible (potential) relationship among soil properties and experimental data attributable to radioactivities of K, Th, U and Rn a detailed investigation has been performed in the Cecita Lake basin (Sila Grande, Calabria, Southern Italy). Most of the soil types outcropping in the Cecita Lake surroundings belong to the Entisol and Inceptisol orders [USDA (United States Department of Agriculture), 2006. Keys to Soil Taxonomy. 10th edit., USDA, Soil Survey Staff, Natural Resources Conservation Service, Washington D.C., 333 pp.], representing relatively young, poorly to moderately differentiated soils, showing features strongly dependent on the nature of the parent rock and the climatic conditions. Disintegrations contributed by K, Th, U and Rn measured respectively in % (K), ppm (U and Th) and kBq/m 3 (Rn), have been related to 13 a priori known soil unit groups with well-defined general features and spatial position. The data have been analysed by using graphical and numerical statistical procedures able to manage compositional data in a correct sample space. The paper summarises the results of this research and highlights the conclusions drawn from these investigations, particularly concerning i) the modelling of the high U variability, a behaviour that tends to homogenise the differences potentially attributable to soil features, with the exception of situations where uranium could be enriched due to adsorption onto iron oxi-hydroxides and/or clay minerals or concentrated in argillic horizons due to illuviation; ii) the discovering of the discriminative effect of the K/Th ratio values, particularly for soil groups where Th behaviour, as other tetravalent actinides, is strongly affected by the presence of mineral colloids or where the presence of clays affects the trapping of K; iii) the clustering of the a priori known soil groups in four new sets characterised by internal similarities for Rn values for which the morphology appears to be the most important discriminative effect.
Journal of Volcanology and Geothermal Research, 2008
This paper focuses on the main morphological, physical, chemical and mineralogical features of an... more This paper focuses on the main morphological, physical, chemical and mineralogical features of an andic-like soil, widely outcropping in the Sila upland plateau of Calabria (southern Italy), and its potential role in tephrostratigraphy. A multidisciplinary and multiscale ...
Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine ... more Lipari, an active volcanic island in the Aeolian magmatic arc, is an excellent area to determine the effects of multiple source lithology, climate, weathering, transport and depositional environment on epiclastic sand composition. Volcaniclastic sand samples from 12 modern beaches were petrographically characterized using the Gazzi–Dickinson method, and the proportions of source rocks in combination with topography in associated coastal drainage basins were quantified using GIS. Several types of bedrock in the 12 drainage basins that are the likely prominent sources for sand at each sampled beach were recognized, and divided into two categories of provenance lithotypes: lavas and pyroclastic rocks ranging in composition from basaltic andesitic, to andesitic, to rhyolitic. Volcanic lithic fragments from Lipari beach sand consist of colourless and black glassy volcanic fragments with lathwork, felsitic, vitric and microlitic textures. Moreover, high amounts of detrital less durable mi...
&lt;p&gt;Geogenic Cr(VI) contamination is a worldwide environmental issue which mainly oc... more &lt;p&gt;Geogenic Cr(VI) contamination is a worldwide environmental issue which mainly occurs in areas where ophiolitic rocks crop out. In these areas Cr (VI) can reach high concentrations into groundwaters becoming highly dangerous for human health. Indeed Cr(VI) is recognized as highly toxic element with high mobility and bioavailability [1]. Due to these features, starting from July 2017, Italian government has lowered the Cr(VI) limit value for drinking water to 10 &amp;#181;g/L. To improve the living standards in contaminated areas, it is needed (i) to understand the release and fate of contaminant during the water-rock interaction and (ii) to develop efficient remediation systems for natural polluted waters. In this regard, a complementary study on genesis and treatment of a Cr-rich groundwater coming from Italian ophiolitic aquifers was conducted. Reaction path modelling is a proven geochemical tool to understand the release of Cr and its oxidation from Cr(III) to Cr(VI) during the water-rock interaction. The generally accepted hypothesis of scientific community is that geogenic Cr(III) oxidation&amp;#160; is driven by the reduction of trivalent and tetravalent manganese (Mn(III); Mn (IV)) [2] whereas in this work the role of trivalent Fe hosted in serpentine minerals was re-evaluated. Unlike Mn, Fe is the main oxidant present in suitable amount in these rocks. Literature data confirmed the presence of Fe(III) into serpentine minerals hence reaction path modelling was performed varying the Fe (III)/Fe(tot) ratio ranging&amp;#160; from 0.60 to 1.00. The theoretical paths, reproduce the analytical concentrations of relevant solutes, including Cr(VI), in the Mg-HCO&lt;sub&gt;3&lt;/sub&gt; water type hosted in the ophiolitic aquifers of Italy [3]. With increasing of Fe(III)/Fe(tot) ratio in serpentine minerals, high Cr(VI) concentration hold into solution until high alkalinity values. In addition, the spring with the highest Cr(VI) content (75 &amp;#181;g/L) was treated to lower its concentration below the threshold values. &amp;#160;In this work membrane technologies were used as&amp;#160; innovative method considering their many benefits, like the improvement of product quality without using chemicals [4]. A laboratory-scale set-up was used to carry out both Nanofiltration (NF) and Reverse Osmosis (RO) experiments. The experiments were conducted on different commercial membranes: one NF membrane module named DK (polyamide) and two RO membrane modules named AD (polyamide) and CD (cellulose).Tests were performed varying the operating pressures, and high Cr(VI) rejections (around 95%) were reached for all tested membranes, leading to a water containing Cr(VI) in concentrations below the threshold limits. The high flux, obtained already at lower operating pressures (27 L/m&lt;sup&gt;2&lt;/sup&gt;h-10bar), combined with high selectivity towards Cr(VI) makes NF a favorable remediation option. The results obtained in this work are in line with the few data available in the literature for natural contaminated waters and there are quite promising for future scientific developments and application.&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;&amp;#160;&lt;/p&gt; &lt;p&gt;References&lt;/p&gt; &lt;p&gt;[1]Marinho B. A. et al., 2019. Environ Sci Pollut Res,&amp;#160;26(3), 2203-2227&lt;/p&gt; &lt;p&gt;[2]Oze C. et al., 2007. Proc. Natl. Acad. Sci. 104, 6544&amp;#8211;6549&lt;/p&gt; &lt;p&gt;[3]Apollaro C. et al., 2019. Sci. Total Environ. 660, 1459-1471&lt;/p&gt; &lt;p&gt;[4]Figoli &amp;#160;A. &amp; Criscuoli &amp;#160;A., 2017. Springer (Singapore); ISBN:9789811056215&lt;/p&gt;
An innovative methodological approach is proposed in this study, based on the chemical analysis o... more An innovative methodological approach is proposed in this study, based on the chemical analysis of different portions of soil horizons (illuvial pedofeatures, pedogenic matrix and skeletal parent rock fragments) by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-...
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