Search results for "Vulcan"
showing 10 items of 510 documents
Relationship between lanthanide contents in aquatic turtles and environmental exposures
2013
International audience; Trace elements released in the environment during agricultural practices can be incorporated and accumulated in biological fluids and tissues of living organisms. The assessment of these exposures were carried out investigating lanthanide distributions in blood and exoskeleton samples collected from Emys trinacris turtle specimens coming from sites with anthropogenic discharge in western and south Sicily, along migration paths of many bird species from Africa to Europe. The data show a significant (Rxy = 0.72; Rxy > 0.67; α = 0.025) linear relationship between the size of turtle specimens and the lanthanide contents in blood lower than 0.4 μg L−1 whereas this relatio…
Metals and metalloids in hair samples of children living near the abandoned mine sites of Sulcis-Inglesiente (Sardinia, Italy)
2014
International audience; The Sulcis-Iglesiente district (SW Sardinia, Italy) is one of the oldest and most important polymetallic mining areas in Italy. Large outcrops of sulfide and oxide ores, as well as the products of the long-lasting mining activity, are present throughout the district releasing significant quantities of metals and metalloids into the surrounding environment. Here are reported concentrations of 21 elements determined in scalp hair samples from children (aged 11-13 years) living in different geochemical environments of southwestern Sardinia: Iglesias, hosting several abandoned mines, and the island of Sant׳Antioco, not affected by significant base metal mineralization ev…
Nitrate, sulphate and chloride contents in public drinking water supplies in Sicily, Italy.
2012
Water samples collected from public drinking water supplies in Sicily were analysed for electric conductivity and for their chloride, sulphate and nitrate contents. The samples were collected as uniformly as possible from throughout the Sicilian territory, with an average sampling density of about one sample for every 7,600 inhabitants. Chloride contents that ranged from 5.53 to 1,302 mg/l were correlated strongly with electric conductivity, a parameter used as a proxy for water salinity. The highest values are attributable to seawater contamination along the coasts of the island. High chloride and sulphate values attributable to evaporitic rock dissolution were found in the central part of…
Preliminary study on trace metal content in manna extracted from Fraxinus angustifolia cultivars in Madonie (Sicily, Italy)
2019
The manna is a product obtained from the elaborate sap solidification that comes out from the incisions made on the stem of some species of the genus Fraxinus L. In this study, we have analyzed 12 samples of manna to determine the chemical composition. Twenty elements (Al, As, Ba, Cd, Co, Cr, Cu, Fe, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, U, V, Zn) were determined using an Inductively Coupled Plasma Mass Spectrometer. The results show that the most abundant elements are Fe > Rb > Al > Cu > Ba > Zn > Sr with median concentrations in the range of 0.9 – 10mg kg-1. The remaining elements exhibit median concentrations in the range of 0.0003 -0.5 mg kg-1. The manna also can be cons…
Outgassing of Mantle Volatiles in Compressional Tectonic Regime Away From Volcanism: The Role of Continental Delamination
2019
In this study we discuss the occurrence of mantle-derived heat and volatiles (i.e., helium and CO 2 ) feeding hydrothermal systems in a seismically active margin between two convergent plates (African and European) without any signals of volcanism. The helium (He) isotopes clearly indicate a mantle-derived component in the outgassing volatiles. The estimated mantle-derived He fluxes are up to two to three orders of magnitude greater than those in a stable continental area. Such high He fluxes cannot be provided by a long-lasting diffusion, thereby implying a more efficient transport (i.e., advective transport through faults). He data coupled to heat-He relationship suggest the occurrence of…
Compensating isothermal calorimeter to investigate the vulcanization of factice
1990
Abstract Sulphur factice is produced from a mixture of a vegetable oil and sulphur for linkage. To start vulcanization, the mixture is heated to temperatures betueen 130 and 150 °C. Within hours or days the temperature increases to about 160 °C and the product solidifies. To investigate the production process and to optimize the reaction, the temperature development was simulated in laboratory-scale experiments and the heat released was measured. In order to investigate the reaction kinetics of the entire vulcanization process, the calorimeter must a11ow the measurement of the mixture in liquid and solid state. The developed compensating calorimeter consists of a hot plate equipped with thi…
Mount Etna volcano (Italy) as a major “dust” point source in the Mediterranean area
2016
Volcanic emissions represent one of the most relevant natural sources of trace elements to the troposphere. Due to their potential toxicity, they may have important environmental impacts from local to global scale. They can also severely affect the atmospheric and terrestrial environment at timescales ranging from a few to millions of years. Mt. Etna volcano is known as one of the largest global contributors of magmatic gases (CO2, SO2 and halogens) and particulate matter, including some toxic trace elements. The aim of this study is to characterize the chemical composition and the mineralogical features of the volcanogenic aerosol passively emitted from Mt. Etna. Twenty-five samples were c…
Freshening of the Mediterranean Salt Giant: controversies and certainties around the terminal (Upper Gypsum and Lago-Mare) phases of the Messinian Sa…
2021
The late Miocene evolution of the Mediterranean Basin is characterized by major changes in connectivity, climate and tectonic activity resulting in unprecedented environmental and ecological disruptions. During the Messinian Salinity Crisis (MSC, 5.97-5.33 Ma) this culminated in most scenarios first in the precipitation of gypsum around the Mediterranean margins (Stage 1, 5.97-5.60 Ma) and subsequently > 2 km of halite on the basin floor, which formed the so-called Mediterranean Salt Giant (Stage 2, 5.60-5.55 Ma). The final MSC Stage 3, however, was characterized by a "low-salinity crisis", when a second calcium-sulfate unit (Upper Gypsum; substage 3.1, 5.55-5.42 Ma) showing (bio)geochemica…
Surface hydrographic changes at the western flank of the sicily channel associated with the last sapropel
2021
Abstract In the eastern Mediterranean Sea, the early Holocene was characterized by major climatic and oceanographic changes that led to the formation of the last sapropel (S1) between 10.8 and 6.1 kyr cal. BP. These hydrographic changes might have altered the water exchange between the eastern and western Mediterranean sub-basins through the Strait of Sicily, but the existing evidences are inconclusive. In the present study we show new evidence from sediment core NDT-6-2016 located at the western flank of the Sicily channel, a key location to monitor the surface/intermediate water exchange between the two Mediterranean sub-basins. We perform paleo-hydrographic reconstructions based on plank…
Reconstruction of the paleoenvironmental changes around the Miocene-Pliocene boundary along a W-E transect across the Mediterranean
2006
Abstract In order to reconstruct the environmental changes at the end of the Messinian salinity crisis, a multidisciplinary study has been carried out with a high sampling resolution of the late Messinian–early Zanclean (Zone MPl 1) sediments along a West–East Mediterranean transect. The studied examples comprise sections from southern Spain (Vera/Almanzora), Balearic Basin (ODP Site 975), Tyrrhenian Basin (ODP Site 974), Sicily (Eraclea Minoa), Zakynthos (Kalamaki), Corfu (Aghios Stefanos), Crete (Aghios Vlasis). Previously analyzed sections from the Levantine Basin (Cyprus and ODP Sites 968 and 969) are used for comparison. The sections have been correlated using planktonic foraminiferal …