Search results for " geochimica"
showing 10 items of 446 documents
Unusually large magmatic CO2 gas emissions prior to a basaltic paroxysm
2010
The low-intensity activity of basaltic volcanoes is occasionally interrupted by short-lived but energetic explosions which, whilst frequently observed, are amongst the most enigmatic volcanic events in Nature. The combination of poorly understood and deep, challenging to measure, source processes make such events currently impossible to forecast. Here we report increases in quiescent degassing CO2 emissions (>10,000 t/day) prior to a powerful explosive event on Stromboli volcano on 15 March 2007. We interpret such large CO2 flux as being sourced by passive gas leakage from a deeply (>4 km) stored magma, whose depressurization, possibly caused by the onset of an effusive eruption on 28 Febru…
Paleoclimatic changes in the Serravallian record of the Mediterranean area
2004
High-spectral-resolution Fabry-Pérot interferometers overcome fundamental limitations of present volcanic gas remote sensing techniques
2023
Remote sensing (RS) of volcanic gases has become a central tool for studying volcanic activity. For instance, ultraviolet (UV) skylight spectroscopy with grating spectrographs (GS) enables SO2 (and, under favourable conditions, BrO) quantification in volcanic plumes from autonomous platforms at safe distances. These measurements can serve volcanic monitoring and they cover all stages of volcanic activity in long measurement time series, which substantially contributes to the refinement of theories on volcanic degassing. Infrared (IR) remote sensing techniques are able to measure further volcanic gases (e.g., HF, HCl, CO2, CO). However, the employed Fourier transform spectrometers (FTSs) are…
Evoluzione di sistemi deposizionali di piattaforma continentale durante il Pleistocene superiore - Olocene: analisi sedimentologica di due carote pre…
2016
E’ stato condotto uno studio sedimentologico di due carote prelevate nell’offshore della Sicilia settentrionale allo scopo di analizzare i cambiamenti di regime deposizionale verificatisi nel Pleistocene superiore - Olocene. Sulle due carote, provenienti dal Golfo di Termini Imerese (2,74 m di lunghezza, profondità -126 m) e dalla Baia di Carini (1,35 m di lunghezza, profondità -194 m), sono state anche eseguite analisi geochimiche e micropaleontologiche. Da un punto di vista granulometrico in entrambe le carote si può notare che la parte inferiore è principalmente costituita da una granulometria grossolana (ghiaia, ghiaia sabbiosa) che passa ad una granulometria di tipo argillo-siltosa nel…
Rainwater-induced leaching of selenium, arsenic and vanadium from Etnean volcanic soils
2009
Active volcanoes emit considerable amounts of contaminants such as As, Se and V. Mount Etna is the biggest volcano of Europe and an excellent geochemical site to study water-soil processes. Due to its volcanic activity, the rainwater has a strong compositional gradient, both in time and space. At present, the behaviour of trace elements in the soils around Mt Etna is poorly understood. To determine the influence of the rainwater pH on the potential mobilization of geogenic pollutants, batch experiments have been performed with synthetic rainwater for 25 soils collected along the flanks of the volcano. Our results show that: i) The maximum concentrations in the leaching solutions are higher …
THE IMPACT OF VOLCANIC EMISSIONS ON ETNA’S SNOW COVER
2011
The CO2 diffusive degassing in Linosa Island (Sicily Channel)
2008
Dis-misure e dis-valori del danno all'ambiente fluviale: un approccio socio-sistemico
2013
Si espone qui la sperimentazione di un metodo di analisi e valutazione del danno ispirato all’approccio sociologico di N. Nuhmann (1990), che definisce l’ambiente per differenza rispetto ai processi comunicativi che informano il sistema sociale e quindi il danno ambientale come difetto della comunicazione tra sub-sistemi. In questa logica la valutazione del risarcimento è stata condotta con riferimento al rapporto verticale tra unità inquinanti e supporto naturale e orizzontale tra i diversi sub-sistemi che comunicano “sull’ambiente”. Il caso studiato riguarda le immissioni di inquinanti in un bacino idrico siciliano da tempo sotto osservazione anche da parte della Comunità Europea a causa …
Gas geochemistry of shallow submarine vents in the Aegean sea (Greece)
2017
The Aegean area, which is geodynamically very active, is characterised by intense seismic activity, presence of active volcanic systems and anomalous geothermal gradients. Like other regions of intense geodynamic activity it is also characterized by extensive geogenic degassing. Gas manifestations are not only widespread on land but are also very frequent underwater. Many of these, as for example those of Milos and Santorini, are known since long time and have been previously studied although the targets were generally the hot waters or the sediments affected by the emissions (Smith and Cronan 1978, Dando et al. 1995, Price et al. 2013, Megalovassilis 2014).The present study aims at produci…
Hydrogeochemical multi-component approach to assess fluids upwelling and mixing in shallow carbonate-evaporitic aquifers (Contursi area, southern Ape…
2023
With the aim of deepening our understanding of deep-seated fluids upwelling and mixing in large regional aquifers, we performed a hydrogeochemical study of twenty-two springs in the Contursi area (upper Sele river valley, southern Apennines) by means of the measurements of chemical-physical parameters, major ions, trace elements, and stable and radioactive isotopes. Besides, we realized two updated geo-structural cross-sections in order to reconstruct the groundwater flowpath in the study area. The hydrogeochemical composition, as well as the water temperature allow to identify-three main groups of groundwater: Cold and Low salinity Groundwater (CLGW), Intermediate Salinity Groundwater (ISG…