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Petrini, Riccardo
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- PublicationRestrictedWater speciation and Sr isotopic exchange during water-melt interaction: a combined NMR-TIMS study on the Cretaio Tephra (Ischia Island,south Italy)(2004)
; ; ; ; ; ;Slejko, F. F.; Dipartimento di Scienze della Terra, Trieste ;Petrini, R.; Dipartimento di Scienze della Terra, Trieste ;Orsi, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Forte, C.; ICQEM-CNR, Pisa; ; ; ; In order to improve the microscopic understanding of the water-magma interaction process during explosive volcanism,volcanic glasses representative of deposits with sedimentological characteristics suggesting different water/melt ratios were studied by a combination of the nuclear magnetic resonance (NMR) and TIMS methods. The glasses were separated from pumices of two surge layers and one fallout bed of the Cretaio Tephra (Ischia Island,Italy), which is the product of an explosive eruption that occurred at Ischia in the second century BC. The 29Si CP^MAS NMR experiments indicate the occurrence of 1H^29Si dipolar couplings in glasses from the phreatomagmatic activity, suggesting the presence of hydrogen atoms in proximity of silicon atoms. This feature is not detected in the glass from the deposit of the magmatic explosion. 1H MAS NMR spectra reveal different peaks attributed to different hydrous species characterized by different motional properties. These include ‘rigid’ H2O groups isolated in the glass structure, more mobile water species and possibly structural hydroxyl groups. 1H MAS NMR spectra recorded after deuteration experiments of the glass at a temperature up to 300‡C revealed that the exchange reactions of the D2O vapor with hydrogen were limited to the most mobile water species,possibly on vesicle surfaces or in channels. The hydrogen concentration linearly correlates with the 87Sr/86Sr isotope ratio in glasses,suggesting isotopic tracer exchanges between the Sr dissolved in the water vapor and the Sr in the silicon-oxygen network during hydration. It is proposed that the uprising melt interacted with a hydrothermal system of seawater-derived fluids,characterized by relatively high Sr isotopic composition.164 81 - PublicationRestrictedHighly radiogenic Sr-isotopic signature and trace element content of grape musts from northern Piedmont vineyards (Italy)(2018)
; ; ; ; ; ; ; ; ; The analysis of trace metals and metalloids, and the Sr-isotopic systematics were applied to 16 must samples from vines growing in the Sesia Val Grande Supervolcano UNESCO Global Geopark in the northern Piedmont Region (Italy), a land worldwide famous for the production of quality Nebbiolo-based red wines. Twenty-four elements were measured in each sample with inductively coupled plasma-mass spectrometry (ICP-MS). The results indicate a wide variability in trace element concentration in musts from the different vineyards. In particular, Rb and Sr reach their maximum at 5110 and 694 µg L−1, respectively, reflecting the geological nature of the magmatic bedrocks. Fe, Cu, Pb and Ba concentrations reach 3118, 1200, 130 and 720 µg L−1, respectively, suggesting a source from iron oxide, Pb–Zn and Ba ores associated to the volcanic activity. The 87Sr/86Sr ratio is in the range 0.711608–0.718160, showing a highly radiogenic signature which is uncommon in must/wine. This is consistent with the high 87Sr/86Sr isotopic ratio of the old rhyolitic bedrocks. Furthermore, the 87Sr/86Sr ratio in musts linearly correlates with the corresponding 87Rb/86Sr ratio, reflecting the Rb and 87Sr release from primary minerals during pedogenesis and matching the initial 87Sr/86Sr ratio of the parent bedrocks magmatic reservoir, thus assuming importance for authenticity assessment.78 1 - PublicationRestrictedCoupling geochemical and geophysical signatures to constrain strain changes along thrust faults(2012-03)
; ; ; ; ; ; ; ; ;Petrini, R.; Dipartimento di Geoscienze, Università di Trieste ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Riggio, A.; Ist. Naz. Oceanografia e Geofisica Sperimentale, Trieste ;Slejko, F.F.; Dipartimento di Geoscienze, Università di Trieste ;Santulin, M.; Ist. Naz. Oceanografia e Geofisica Sperimentale, Trieste ;Buccianti, A.; Dipartimento di Scienze della Terra, Università di Firenze ;Bonfanti, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Slejko, D.; Ist. Naz. Oceanografia e Geofisica Sperimentale, Trieste; ; ; ; ; ; ; Anomalous geochemical signals inferred from elemental and isotopic analyses on spring waters and soil degassing are often detected in response to tectonic loading along faults. Recent results highlighted how the geochemical anomalies are closely related to episodes of crustal deformation. In the present study, the carbon dioxide and radon from soil degassing and the geochemical features of springs spatially related to fault zones in the Friuli-Venezia Giulia region (north-eastern Italy), a seismic-prone area, have been coupled with crustal deformation analyses to better define the possible correlations between fluctuations of geochemical parameters and seismicity, with the aim of gaining new information about local geodynamic processes. The natural CO2 and Rn degassing was evaluated by a soil gas survey carried out by a grid of about 100 measuring sites located over the area that had been hit by strong earthquakes, in the past (Gemona – Idrija 1511, Raveo 1700, Tolmezzo 1788 and 1928, Gemona 1976). The results obtained show a significant amount of crustal-originated gases, especially CO2, possibly related to decarbonation reactions and stress accumulation occurring in deep-seated structures. The spring waters show, in some cases, anomalous geochemical transients, in particular concerning the chloride and Rn concentration, that are not related to seasonal changes and interpreted to reflect distinct fluid pressure regimes within the fault zone, yielding the leakage of pore fluids into the country-rock aquifers. In particular, the changes in the chloride content have been tentatively modeled in terms of pore-fluid expulsion from compacting clays during pressure gradients at shallow crustal levels. The flow regimes and chemical evolution have been related to the strain computed at the outlet sites through the Gutenberg–Richter relation parameters and the regional value of the strain rate. The information provided here may be used to start up a long-term geochemical monitoring of this seismically active area able to detect the modifications occurring in the circulating fluids to gain a better insight on the relationships between the geochemistry of the fluids and the activity of the local seismogenic faults.941 24 - PublicationRestrictedEvidence for Multi-stage Magmatic Evolution during the past 60 kyr at Campi Flegrei (Italy) Deduced from Sr, Nd and Pb Isotope Data(2002)
; ; ; ; ; ; ; ; ; The Campi Flegrei caldera, an active volcanic field in the Campanian province, Italy, is a nested structure generated by the Campanian Ignimbrite (37 ka BP) and the Neapolitan Yellow Tuff (12 ka BP) eruptions. Since at least 60 ka BP Campi Flegrei has produced magmas with variable chemical and Sr isotopic compositions. 87Sr/86Sr ratios increase through time from 0·7068 to 0·7086, with the highest ratios detected in the least-evolved shoshonitic products. The origin of this progressive Sr isotopic variability has been investigated using new Sr, Nd and Pb isotopic data for volcanic rocks and entrained xenoliths. The data obtained are combined and discussed with previous geochemical and Sr isotope data and used to suggest a multi-stage evolution for the magmatic system, mainly involving deeper and shallower crustal magma storage reservoirs. The deeper reservoir is proposed to be a magma chamber periodically refilled by primitive mafic magmas which subsequently undergo contamination by crustal material. The assimilated crustal material is represented by xenoliths recovered in the shoshonitic pyroclastic products. Magma batches originating from the deeper reservoir migrated towards the surface and fed a shallower complex magmatic system. The deeper chamber was tapped during the eruption of least evolved magmas by regional fault systems. In addition to crystal–liquid fractionation, open-system processes occurred in the shallower system.81 3 - PublicationRestrictedNatural arsenic contamination in waters from the Pesariis village, NE Italy(2011)
; ; ; ; ; ; ; ; ;Petrini, R. ;Slejko, F. ;Lutman, A. ;Pison, S. ;Franceschini, G. ;Zini, L. ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Galic, A. ; ; ; ; ; ;; High arsenic (As) concentrations, [900 lg/L, were measured in Ca–Mg–SO4 waters from springs and drainages in the village of Pesariis in the Carnic Alps (NE Italy). Oxidation of the outcropping arsenian marcasite ore deposits of the area is proposed as the mechanism for As release into oxygenated waters during runoff. Nevertheless, the limited extension of the ore deposit and the relatively low As content of the mineralization suggest that sulfide weathering might not be the only process responsible for the highest As concentration in groundwaters. An additional mechanism involves As adsorption onto ferric iron particulate during oxidation, the drawdown in reducing environment at depth during water infiltration, and the release of ferrous iron and sorbed arsenic to the water columns by reductive dissolution of hydrous ferric oxides (HFO). This yields the observed Fe–As correlation. Newly formed HFO precipitates when groundwaters discharge to aerated conditions, leading to the removal of As, which strongly partitions into the iron-rich sediments, adsorbed onto the surface of amorphous Fe2O3 xH2O. The calculated and measured As concentration in sediments exceeds 10% by weight. Furthermore, geochemical and isotopic data indicate that the As-rich reservoir partly mixes with shallower aquifers, commonly tapped for drinking supply, representing a natural hazard for inhabitants.312 76 - PublicationRestrictedPreliminary geochemical and isotopic data on springs along the Fella-Sava fault zone (NE Italy)(2007-12)
; ; ; ; ; ;Slejko, F.; OGS - Trieste ;Petrini, R.; UNI-TS ;Carulli, G. B.; UNI-TS ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Ditta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; ; ; ; During 2006, a geochemical survey was carried out on three perennial springs discharging along a segment of the Fella-Sava line, a transpressive lineament running in the eastern Southern Alps (Friuli, NE Italy). Waters have both a Ca-bicarbonate and a CaMg(Na)-HCO3SO4 sulfureous character. Oxygen and hydrogen isotopic data indicate a meteoric origin from catchments with different mean topographic elevation. The Sr isotopic composition of the Ca-bicarbonate water is consistent with circulation in Middle Triassic limestones; sulfureous waters have 87Sr/86Sr isotopic ratios which indicate interactions with the Upper Permian dolomite-evaporite layers, the latter representing the preferential decollement horizons during the compressive Alpine cycle. The isotopic data, the negative redox potential and the tritium activity for sulfureous springs suggest a long-lasting flow through different fracture systems. Limited effects of mixing between the deeper and superficial, low-salinity waters are observed. Speciation calculations indicate that sulfureous waters are oversaturated in calcite and silicate minerals, suggesting that cement deposition is an active process along the flowpaths. The formations of diagenetic seals in a compressive regime would contribute to fluid overpressuring in pores at a relatively shallow depth, where part of the seismic activity is concentrated. The SO4, Ca and Mg concentrations, in one of the sulfureous springs, show a marked increase which seems to be related to the seismic events in the area, and is attributed to the expulsion of pore fluids with high concentration of sulphate due to strain changes347 27 - PublicationRestrictedHelium and carbon isotopes in the dissolved gases of Friuli Region (NE Italy): Geochemical evidence of CO2 production and degassing over a seismically active area(2009-08)
; ; ; ; ; ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Bonfanti, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Ditta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Petrini, R.; Dipartimento di Scienze della Terra, University of Trieste ;Slejko, F.; Dipartimento di Scienze della Terra, University of Trieste; ; ; ; The first geochemical data showing the existence of an active degassing activity over a large seismically active sector of the Southern Alps (Friuli Region, NE Italy) are presented. The dissolved gases, helium and carbon isotopic systematics of 46 water samples taken from 13 sites running along E–W and NE–SW faults besides the natural degassing of a 5000 km2 wide area are investigated. The chemical composition of the dissolved gases revealed that a CO2-rich gas phase feeds the local groundwaters. 3He/4He ratios (R) normalized to the atmospheric 3He/4He ratio (Ra=1.39×10−6) and corrected for the atmospheric contamination (R/Rac), range from 0.29 to 1 as a result of a two component (radiogenic and atmospheric) mixing. The δ13C values of total dissolved inorganic carbon (TDIC) ranging from −15.28 to −0.75‰ vs. PDB, show the occurrence of multiple gas–water interactions. The mixing between the atmospheric air and a crustal source and the gas–water interactions occurring at various extents appears to be the main control on the observed He–C systematics. The natural CO2 degassing was evaluated by a soil gas survey carried out by a grid of about 100 measuring sites located over the area that generated destructive seismic sequences (e.g. the Gemona sequence of 1976; main shocks M6.4 of 6th May and M6.1 of 11th and 15th September). The results obtained show that a significant amount of crustal-originated gases are released over the continental area of Eastern Southern Alps. The evidence that carbon dioxide is associated with radiogenic-type helium denotes the lack of the mantle as primary energy and degassing source, highlighting the possibility that CO2 is produced by thermo-mechanical processes occurring at seismogenic depth. The information provided here may be used to start up a long-term geochemical monitoring of this seismically active area and could be able to detect the modifications occurring to the circulating fluids to gain a better insight on the relationships between the fluids' geochemistry and the activity of the local seismogenic faults.745 21 - PublicationRestrictedGeochemical monitoring of the 2012 Po Valley seismic sequence: A review and update(2017)
; ; ; ; ; ; ; ; ; A seismic swarm characterized by a Ml= 5.9 mainshock occurred in the Po Valley, northern Italy, in 2012. The area has been studied for active compressional tectonics since the beginning of the twentieth century. A variety of geophysical and geochemical parameters have been utilized with the purpose of identifying possible precursory signals. This paper considers groundwater level data and geochemical data both in groundwaters and in gases. All considered parameters have led to the conclusion that possible long and medium precursory trends have been identified in geofluids. No short-term precursors have been clearly identified. Hydrogeological and geochemical monitoring could be more effectively utilized in a different geological context, and seismic hazard reduction procedures could benefit from geofluid monitoring.401 3 - PublicationOpen AccessGeochemical features and effects on deep-seated fluids during the May-June 2012 southern Po Valley seismic sequence(2012-10)
; ; ; ; ; ; ; ; ; ;Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Liotta, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Martelli, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Martinelli, G.; ARPA Emilia ;Petrini, R.; Univ. Trieste ;Riggio, A.; OGS Trieste ;Rizzo, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia ;Slejko, F.; Univ. Trieste ;Stenni, B.; ARPA Emilia; ; ; ; ; ; ; ; A periodic sampling of the groundwaters and dissolved and free gases in selected deep wells located in the area affected by the May-June 2012 southern Po Valley seismic sequence has provided insight into seismogenic-induced changes of the local aquifer systems. The results obtained show progressive changes in the fluid geochemistry, allowing it to be established that deep-seated fluids were mobilized during the seismic sequence and reached surface layers along faults and fractures, which generated significant geochemical anomalies. The May-June 2012 seismic swarm (mainshock on May 29, 2012, M 5.8; 7 shocks M >5, about 200 events 3 > M > 5) induced several modifications in the circulating fluids. This study reports the preliminary results obtained for the geochemical features of the waters and gases collected over the epicentral area from boreholes drilled at different depths, thus intercepting water and gases with different origins and circulation. The aim of the investigations was to improve our knowledge of the fluids circulating over the seismic area (e.g. origin, provenance, interactions, mixing of different components, temporal changes). This was achieved by collecting samples from both shallow and deep-drilled boreholes, and then, after the selection of the relevant sites, we looked for temporal changes with mid-to-long-term monitoring activity following a constant sampling rate. This allowed us to gain better insight into the relationships between the fluid circulation and the faulting activity. The sampling sites are listed in Table 1, along with the analytical results of the gas phase.193 161