396 research outputs found
Soil CO2 emissions at Furnas volcano (São Miguel Island, Azores archipelago) - volcano monitoring perspectives, geomorphologic studies and land-use planning application
Carbon dioxide (CO2) diffuse degassing structures (DDS) at Furnas Volcano (São
Miguel Island, Azores) are mostly associated with the main fumarolic fields, evidence
that CO2 soil degassing is the surface expression of rising steam from the hydrothermal
system. Locations with anomalous CO2 flux are mainly controlled by tectonic structures
oriented WNW-ESE and NW-SE and by the geomorphology of the volcano, as
evidenced by several DDS located in depressed areas associated with crater margins.
Hydrothermal soil CO2 emissions in Furnas volcano are estimated to be ~ 968 t d-1.
Discrimination between biogenic and hydrothermal CO2 was determined using a
1
statistical approach and the carbon isotope composition of the CO2 efflux. Different
sampling densities were used to evaluate uncertainty in the estimation of the total CO2
flux, and showed that a low density of points may not be adequate to quantify soil
emanations from a relatively small DDS. Thermal energy release associated to diffuse
degassing at Furnas caldera is about 118 MW (from an area of ~ 4.8 km2) based on the
H2O/CO2 ratio in fumarolic gas. The DDS affect also Furnas and Ribeira Quente
villages, which are located inside the caldera and in the south flank of the volcano,
respectively. At these sites, 58% and 98% of the houses are built over hydrothermal
CO2 emanations, and the populations are at risk due to potential high concentrations of
CO2 accumulating inside the dwellings.
Keywords: Soil diffuse degassing; soil CO2 flux; emission rates; Azores archipelago
Carbon dixide emission in Italy: Shallow crustal sources or subduction related fluid recycling?
Anomalous non-volcanic CO2 release in central and
southern Italy has been highlighted by ten years of detailed
investigations on Earth degassing processes. Two regional
degassing structures are located in the Tyrrhenian sector
where more then 200 emissions of CO2 are located and has
been recently included in the first web based catalogue of
degassing sites (http://googas.ov.ingv.it). The total amount of
CO2 released by the two structures were evaluated to be >
2×1011 mol a-1 ( >10% of the estimated global volcanic CO2
emission). The anomalous flux of CO2 suddenly disappears in
the Apennine in correspondence of a narrow band where most
of the Italian seismicity concentrates. Here, at depth, the gas
accumulates in crustal traps generating CO2 overpressurised
reservoirs. These overpressured structures are, in our opinion,
one of the main cause of Apennine earthquake activation
processes. The results of these investigations suggested that
Earth degassing in Italy may have an active primary role in the
geodynamics of the region. What is the origin of gas? The
large extension of the degassing structures and petrologic data
suggested that the main source of gas is a mantle
metasomatised by the fluids produced in the subdacted slabs.
However, has been also hypothesised the presence of localised
crustal source of the gas. This matter will be discussed on the
base of unpublished isotopic data of the main gas emissions
Carbon Dioxide degassing at Latera caldera (Italy): evidence of geothermal reservoir and evaluation of its potential energy
In order to test the potentiality of soil CO2 diffuse degassing measurements for the study of underground mass and heat transfer in geothermal systems detailed surveys were performed at Latera Caldera which is an excellent test site, due to the abundant available subsurface data. Over 2500 measurements of soil CO2 flux revealed that endogenous CO2 at Latera Caldera concentrates on a NE-SW band coinciding with a structural high of fractured Mesozoic limestones hosting a water-dominated high-enthalpy geothermal reservoir. The total hydrothermal CO2 degassing from the structural high has been evaluated at 350 t d-1 from an area of 3.1 km2. It has been estimated that such a CO2 release would imply a geothermal liquid flux of 263 kg s-1, with a heat release of 239 MW. The chemical and isotopic composition of the gas indicates a provenance from the geothermal reservoir and that CO2 is partly originated by thermal metamorphic decarbonation in the hottest deepest parts of the system and partly has a likely mantle origin. The ratios of CO2, H2, CH2 and CO to Ar, were used to estimate the T-P conditions of the reservoir. Results cluster at T ~ 200-300°C and PCO2 ~ 100-200 bars, close to the actual well measurements. Finally the approach proved to be an excellent tool to investigate the presence of an active geothermal reservoir at depth and that the H2-CO2-CH4-CO-Ar gas composition is a useful T-P geochemical indicator for such CO2 rich geothermal systems
One year of geochemical monitoring of groundwater in the Abruzzi region after the 2009 earthquakes.
The presence of a deep and inorganic source of CO2 has been recently recognized in Italy on the basis of the
deeply derived carbon dissolved in the groundwater. In particular, the regional map of CO2 Earth degassing
shows that two large degassing structures (Tuscan Roman degassing structure, TRDS, and Campanian degassing
structure, CDS) affect the Tyrrhenian side of the Italian peninsula. The comparison between the map of CO2
Earth degassing and of the location of the Italian earthquakes highlights that the anomalous CO2 flux suddenly
disappears in the Apennine in correspondence of a narrow band where most of the seismicity concentrates. A
previous conceptual model proposed that in this area, at the eastern borders of TRDS and CDS, the CO2 from the
mantle wedge intrudes the crust and accumulate in structural traps generating over-pressurized reservoirs. These
CO2 over-pressurized levels can play a major role in triggering the Apennine earthquakes.
The 2009 Abruzzo earthquakes, like previous seismic crises in the Northern Apennine, occurred at the border of
the TRDS, suggesting also in this case a possible role played by deeply derived fluids in the earthquake generation.
Detailed hydro-geochemical campaigns, with a monthly frequency, started immediately after the main shock of
the 6th of April 2009. The new campaigns include the main springs of the area which were previously studied in
detail, during a campaign performed ten years ago, constituting a pre-crisis reference case. Almost one year of
geochemical data of the main dissolved ions, of dissolved gases (CO2, CH4, N2, Ar, He) and of the stable isotopes
of the water (H, O), CO2 (13C) and He (3He/4He), highlight both that the epicentral area of L’Aquila earthquakes
is affected by an important process of CO2 Earth degassing and that that the gases dissolved in the groundwater
reflects the input in to the aquifers of a deep gas phase, CO2- rich, with an high He content and with low 3He/4He
ratios, similar to the gases emitted by natural manifestations located in the northern Apennines which are fed by
deep pressurized reservoirs. Furthermore a systematic increase in the content of the deeply derived CO2 dissolved
in the aquifers occurred respect to the July 1997 samples. This increase, followed by a gentle decline of the
anomaly, can be compatible with the occurrence of an episode of deep CO2 degassing concurrently with the earthquakes.
The origin of this regional variation is under investigation and, at the present moment, an unambiguous
interpretation of the data is not possible because the lack of a systematic monitoring of the springs before the
seismic events and because eventual seasonal effects on observed variation in CO2 flux are still under investigatio
First observations of the fumarolic gas output from a restless caldera: implications for the current period of unrest (2005–2013) at Campi Flegrei
The fumarolic gas output has not been quantified for any of the currently deforming calderas
worldwide, due to the lack of suitable gas flux sensing techniques. In view of resumption of ground uplift
(since 2005) and the associated variations in gas chemistry, Campi Flegrei, in southern Italy, is one of the
restless calderas where gas flux observations are especially necessary. Here we report the first ever
obtained estimate of the Campi Flegrei fumarolic gas output, based on a set of MultiGAS surveys
(performed in 2012 and 2013) with an ad-hoc-designed measurement setup. We estimate that the current
Campi Flegrei fumarolic sulphur (S) flux is low, on the order of 1.5–2.2 tons/day, suggesting substantial
scrubbing of magmatic S by the hydrothermal system. However, the fumarolic carbon dioxide (CO2)
output is 4606160 tons/day (mean6SD), which is surprisingly high for a dormant volcano in the
hydrothermal stage of activity, and results in a combined (fumarolesþsoil) CO2 output of 1560 tons/
day. Assuming magma to be the predominant source, we propose that the current CO2 output can be
supplied by either (i) a large (0.6–4.6 km3), deeply stored (>7 km) magmatic source with low CO2
contents (0.05–0.1 wt%) or (ii) by a small to medium-sized ( 0.01–0.1 km3) but CO2-rich (2 wt%)
magma, possibly stored at pressures of 100 to 120 MPa. Independent geophysical evidence (e.g.,
inferred from geodetic and gravity data) is needed to distinguish between these two possibilities
Hellenic karst waters: geogenic and anthropogenic processes affecting their geochemistry and quality
Karst hydrosystems represent one of the largest global drinking water resources, but they are
extremely vulnerable to pollution. Climate change, high population density, intensive industrial, and
agricultural activities are the principal causes of deterioration, both in terms of quality and quantity,
of these resources. Samples from 172 natural karst springs were collected in the whole territory of
Greece. To identify any geogenic contamination and/or anthropogenic pollution, analyses of their
chemical compositions, in terms of major ions and trace elements, were performed and compared to
the EU limits for drinking water. Based on chloride content, the collected karst springs were divided
into two groups: low-chloride (< 100 mg L−
1) and high-chloride content (> 100 mg L−
1). An additional
group of springs with calcium-sulfate composition was recognised. Nitrate concentrations were
always below the EU limit (50 mg L−
1), although some springs presented elevated concentrations.
High contents in terms of trace elements, such as B, Sr, As, and Pb, sometimes exceeding the limits,
were rarely found. The Greek karst waters can still be considered a good quality resource both for
human consumption and for agriculture. The main issues derive from seawater intrusion in the
aquifers along the coasts. Moreover, the main anthropogenic pollutant is nitrate, found in higher
concentrations mostly in the same coastal areas where human activities are concentrated. Finally,
high levels of potentially harmful trace elements (e.g. As, Se) are very limited and of natural origin
(geothermal activity, ore deposits, etc.)
Fault weakening due to CO2 degassing in the Northern Apennines: short- and long-term processes
The influx of fluids into fault zones can trigger two main types of weakening
processes that operate over different timescales and facilitate fault movement and
earthquake nucleation.
Short-term and long-term weakening mechanisms along faults require a
continuous fluid supply near the base of the brittle crust, a condition satisfied in the
extended/extending area of the Northern Apennines of Italy. Here carbon mass
balance calculations, coupling aquifer geochemistry to isotopic and hydrological data, define the presence of a large flux (∼12,160 t d-1) of deep-seated CO2 centred in the
extended sector of the area. In the currently active extending area, CO2 fluid
overpressures at ∼85% of the lithostatic load have been documented in two deep (4-5
km) boreholes.
In the long-term, field studies on an exhumed regional low-angle normal fault
show that during the entire fault history, fluids reacted with fine-grained cataclasites
in the fault core to produce aggregates of weak, phyllosilicate-rich fault rocks that
deform by fluid assisted frictional-viscous creep at sub-Byerlee friction values (μ <
0.3). In the short-term, fluids can be stored in structural traps, such as beneath mature
faults, and stratigraphical traps such as Triassic evaporites. Both examples preserve
evidence for multiple episodes of hydrofracturing induced by short-term cycles of
fluid pressure build-up and release.
Geochemical data on the regional-scale CO2 degassing process can therefore be
related to field observations on fluid rock interactions to provide new insights into the
deformation processes responsible for active seismicity in the Northern Apennines
Acute kidney injury and acute kidney disease in high-dose cisplatin-treated head and neck cancer
Background: In locally advanced head and neck squamous cell carcinoma (LA-SCCHN) at least 200mg/m2 (standard dose 300 mg/m2) of cisplatin concomitant with radiotherapy represents the standard of care, both in postoperative and conservative settings. Nevertheless, high dose administration every 3 weeks is often replaced with low dose weekly cisplatin to avoid toxicities like kidney injury, though often failing to reach the therapeutic dose. Our aim was to investigate the incidence of renal impairment in the real-life setting, integrating high dose cisplatin with adequate supportive therapy, and to explore both Acute Kidney Injury (AKI) and Acute Kidney Disease (AKD), a recently described clinical renal syndrome that encompasses functional alterations of the kidney lasting fewer than 3 months. Methods: One hundred and nine consecutive patients affected by LA-SCCHN and treated with at least a cumulative dosage of 200 mg/m2 of cisplatin concomitant with radiotherapy were enrolled in this prospective observational study. Results: AKI was reported in 12.8% of patients, 50% of whom were stage 1 (KDIGO criteria), while 25.7% of the cohort developed AKD. Patients with baseline estimated Glomerular Filtration Rate (eGFR) < 90 ml/min showed a higher incidence of AKD (36.2% vs 17.7%). Hypertension, baseline eGFR, and therapy with Renin-angiotensin-aldosterone system inhibitors proved to be significant factors associated with both AKI and AKD. Conclusion: AKI and AKD are not rare complications of high-dose cisplatin, but an appropriate prevention strategy and accurate monitoring of patients during treatment could lead to a reduction of the burden of these conditions
A score including ADAM17 substrates correlates to recurring cardiovascular event in subjects with atherosclerosis
Atherosclerosis disease is a leading cause for mortality and morbidity. The narrowing/rupture of a vulnerable atherosclerotic plaque is accountable for acute cardiovascular events. However, despite of an intensive research, a reliable clinical method which may disclose a vulnerable patient is still unavailable
- …