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  • 1
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    The Arjuno-Welirang volcanic complex and the connected Lusi system: Geochemical evidences (2018)
    Elsevier
    In:  Marine and Petroleum Geology, 90 . pp. 67-76.
    Details
    Publication Date: 2021-02-08
    Description: For the first time we present the geochemical characterization of fluids emitted from the Arjuno-Welirang volcanic complex and compare the results with those obtained sampling the neighboring spectacular Lusi eruption site (Java Island, Indonesia). The isotopic composition of the hydrothermal and cold waters from the Welirang volcanic complex indicate a meteoric origin for these springs, with values ranging from −65 to −50 and −6 to −1‰ vs V-SMOW respectively for δD and δ18O. The water erupted from the Lusi site showed clustered higher δD and δ18O isotopic values, ranging around −6 and +10 vs V-SMOW respectively. We ascribe these results to mixing between hydrothermal fluids, meteoric water, saline formation fluids, and water released during clay mineral illitization ultimately altered by additional evaporation processes. The chemical and isotopic composition of fluids emitted from fumaroles and hydrothermal springs of the Welirang volcano showed a clear magmatic signature where a CO2-dominated gas reveals δ13CCO2 ranging between −5.9 and −2.4 and helium isotope with R/Ra = 7.3. These values are very close to those measured at Lusi site (R/Ra = 7) that also have high CO2/CH4 ratio (1.7–2.2) supporting the high contribution of magmatic gases. Moreover, a great contribution of andesitic water has been recognized in the water vapour emitted from the summit fumaroles. Converging geochemical data indicate that the plumbing system of the Lusi eruption site is connected at depth with the Arjuno-Welirang volcanic complex. These data support a scenario where hydrothermal fluids from the volcanic system migrated in the sedimentary basin triggering metamorphic reactions in the organic-rich sediments that ultimately resulted in a venting system at the surface. After eleven years of incessant activity this venting system remains constantly fed by the fluids from the volcanic complex and became world known as “Lusi”, the largest ongoing clastic geysering system on Earth.
    Type: Article , PeerReviewed , info:eu-repo/semantics/article
    Format: text
    DOI: 10.1016/j.marpetgeo.2017.10.015
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    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 2
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    Geochemical and geoelectrical characterization of the Terre Calde di Medolla (Emilia-Romagna, northern Italy) and relations with 2012 seismic sequence (2020)
    Elsevier
    Details
    Publication Date: 2021-01-08
    Description: Soil gas and Electrical Resistivity Tomography (ERT) surveys were performed in Medolla (Emilia-Romagna Region, northern Italy) within a farming area characterized by macroseeps, absence of vegetation and anomalous temperatures of soil to investigate the soil gas migration mechanism and verify the presence of a buried fault intersecting the macroseeps. Soil gas (222Rn, 220Rn, He and C2H6) concentrations and flux (φCO2 and φCH4) measurements were carried out from 2008 to 2015, comprising the 2012 Emilia seismic sequence. Moreover, in 2016 a ERT survey, combined with new flux measurements, was performed along four profiles (ranging from 180 to 630 m long) centered on the main macroseep. We found that the seismic sequence sensibly influenced the soil gas distribution in the area. All investigated species, but He, increased their values early after the mainshocks, likely due to crustal deformation which promoted the geogas uprising. In 2015, when the stress has vanished, these concentrations gradually decreased toward pre-seismic values. Helium concentrations showed an opposite behavior as they decreased in May 2012 and then gradually increased over time. This trend may be reasonably due to the enhancement of the strain field which promoted the He dissipation from soil to the atmosphere, due to its high volatility. In all the geochemical surveys conducted from 2008 to 2015, soil gas high values around the main macroseeps were identified, delighting the presence of an alignment in the E-W direction. This trend, identified for several gas species, ultimately supports the theory of a hidden fault which favors the intensification of fluids migration along zones characterized by greater permeability. ERT results highlighted a sub-horizontal layering characterized by different resistivity intervals, roughly matching local stratigraphy. In most profiles we observed a slightly increase of resistivity and a sharp inter-ruption of the electro-layering in correspondence of the main macroseep, both near the surface and at depth. This implies that a fracture zone due to the presence of a buried fault cannot be excluded. The combined use of geochemical and geophysical techniques in this study confirmed the usefulness of such multiparametric approach for mapping out hidden structures in tectonically active areas, allowing to better understanding the fluid migration processes through preferential leakage pathways.
    Description: Published
    Description: 106678
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: JCR Journal
    Keywords: Soil gas survey ; Electrical Resistivity Tomography (ERT) survey ; Migration pathways ; Medolla ; 04.02. Exploration geophysics ; 03.04. Chemical and biological
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    Geological hazard assessment of the coastal area of Rome (Central Italy) from multi-source data integration (2022)
    Elsevier
    Details
    Publication Date: 2022-02-03
    Description: This work presents the first 3D geological model of the Rome coastal area that integrates available subsurface geological, stratigraphic and geophysical data with surface geochemical data obtained both from the literature and new surveys. The model provides new insights into the stratigraphic and tectonic setting of the area and the geological factors controlling both natural and human-induced gas emissions. This sector of the Italian Tyrrhenian margin has been historically affected by natural emissions of deep CO2 and thermogenic CH4, stored in permeable layers but with local migration to the surface along buried normal faults. In addition to natural processes, human activities can also cause leakage and serious health risks, such as the abrupt gas release in August 2013, that was triggered by borehole drillings near the Rome international airport. The presented 3D reconstruction unveils the link between faults, stratigraphy, lithology and the distribution of the soil gas anomalies. It provides information about the depth of the reservoir that can potentially trap endogenous gases, and the location and geometry of the main faults along which the gas migrates towards the surface. Furthermore, reconstruction of the distribution and thickness of important clay layers better constrains the low permeable areas that prevent gas escape. The 3D model, coupled with the geochemical information, can serve as a useful tool for the local administration to perform land-use planning and manage the local geological and degassing hazards that affect this highly urbanized area near Rome. Furthermore, we estimate that the large amount of CO2 broadly released in the area also provides a contribution to the budget of natural greenhouse gases in the atmosphere.
    Description: Published
    Description: 106527
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: 3D geological model ; Soil gas ; Active faults ; Surface degassing ; Geological hazards ; Tiber delta ; 04.04. Geology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
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    Shallow submarine mud volcano in the northern Tyrrhenian sea, Italy (2020)
    Elsevier
    Details
    Publication Date: 2023-11-16
    Description: Submarine methane emissions in the Tuscan Archipelago have been studied since the 1960s, both for economic and research purposes. Offshore gas seepage is mainly concentrated southward and westward of Elba island, along N–S faults related to recent extensional activity in the Tuscan shelf and N–S trending positive magnetic anomalies, which have been interpreted as serpentinites associated with ophiolitic rocks due to their very high magnetic susceptibility. This study focuses on the gas chemistry of a new emission site corresponding to a shallow water mud volcano in the Scoglio d’Affrica area. The Scoglio d’Affrica seep has a gas composition typical of mud volcanoes, with methane as the prevalent component (95 vol%) and minor gases which include carbon dioxide, nitrogen and trace amounts of helium. The combined stable C and H isotope composition of CH4 (δ13C and δ2H) and the enrichment in heavy carbon isotopes of CO2, highlight a prevalent secondary microbial origin for these fluids (δ13C~− 35.8‰ vs VPDB; δ2H~− 166‰ vs VSMOW; δ13CCO2 up to + 21.7‰ vs VPDB). Thus, in spite of the occurrence of positive magnetic anomalies, a possible abiotic origin of methane is excluded. Moreover, the gas from the mud volcano is extremely depleted in 3He and presents typical 3He/4He ratios of a geological setting in which radiogenic crustal helium is strongly predominant. A photo-mosaic of the mud volcano is also reported. A possible connection with other submarine methane emissions in the Tuscan Archipelago is limited to emissions located few kilometers from the Scoglio d’Affrica area. Recent emissions in the area suggest that gases similar in composition from distinct reservoirs, find their way to the surface from Eocene deposits in different time intervals and through different faults and fractures, placed along the Elba-Pianosa ridge.
    Description: Published
    Description: 104722
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Submarine emission ; Mud volcano ; Methane ; Gas geochemistry ; Tyrrhenian sea ; Geochemistry ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
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    Explosive mud volcano eruptions and rafting of mud breccia blocks (2020)
    Elsevier
    Details
    Publication Date: 2023-11-21
    Description: Azerbaijan hosts the highest density of subaerial mud volcanoes on Earth. The morphologies characterizing these structures vary depending on their geological setting, frequency of eruption, and transport processes during the eruptions. Lokbatan is possibly the most active mud volcano on Earth exhibiting impressive bursting events every ∼5 years. These manifest with impressive gas flares that may reach more than 100 meters in height and the bursting of thousands of m3 of mud breccia resulting in spectacular mud flows that extend for more than 1.5 kilometres. Unlike other active mud volcanoes, to our knowledge Lokbatan never featured any visual evidence of enduring diffuse degassing (e.g., active pools and gryphons) at and near the central crater. Only a very small new-born gryphon was intermittently active in 2019 (with negligible flow). Gas flux measurements completed with a closed-chamber technique reveal extremely low values throughout the structure with average CH4 = 1.36 tonnes yr−1 and CO2 = 11.85 tonnes yr−1. We suggest that after eruptive events, the mud breccia is able to seal the structure preventing gas release and thereby promoting overpressure build-up in the subsurface. This self-sealing mechanism allows a fast recharge of Lokbatan resulting in more frequent and powerful explosive episodes. Our field observations reveal the presence of large (up to ∼50,000 m3) stratified blocks that were originally part of a large crater cone. These blocks were rafted 〉1 km from the vent on top of mud breccia flows. We use a model based on lubrication theory to show that it is reasonable to transport blocks this large and this far provided the underlying mud flow was thick enough and the blocks are large enough. The presence of large rafted blocks is not a unique phenomenon observed at Lokbatan mud volcano and is documented at other large-scale structures both onshore and offshore.
    Description: Published
    Description: 116699
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Lokbatan mud volcano Azerbaijan ; rafted mud breccia megablocks ; gas flux ; self-sealing ; explosive eruptions ; lubrication theory ; Solid Earth ; Geochemistry
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
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    Hydrogeochemical investigation of shallow aquifers before and after the 2012 Emilia seismic sequence (northern Italy) (2023)
    Elsevier
    Details
    Publication Date: 2023-03-13
    Description: Soon after the MW = 6.0 main event of May 20, 2012 that struck the central part of the Emilia-Romagna region (Italy), several geochemical surveys were carried out on groundwater within the epicentral area. A total of 20 water samples were periodically collected, from May 2012 to July 2014, from shallow (up to 6 m depth) to deep (down to 175 m depth) wells within both unconfined and confined aquifers and analyzed for major ions, trace elements, dissolved gases and stable isotopes (δ2H–H2O, δ18O–H2O and δ13C-TDIC). Geochemical data were compared with previous data collected and analyzed in 2006 in a phase of absence of significant seismic activity. Monitored waters showed concentration variations in post-earthquake sampling on a large number of geochemical parameters. Many of these variations were recorded during the co-seismic phase and were transient as the geochemical parameters returned towards pre-earthquake values over time. The most significant transient variations involved trace elements, which generally show high sensitivity even to small variations in the surrounding environment due to their usually low concentrations in groundwater. Physical-chemical parameters (water temperature, pH, TDS) and major ions provided less unambiguous indications, whereas among dissolved gases CH4 and CO2 showed a general post-seismic increase within the unconfined aquifer. Increased contents of such gas species in both aquifers (this study) and soils (previous studies) suggest that the seismic-induced overpressure on the ground had enhancing effects on soil permeability and porosity and triggered their co-seismic migration upwards from deeper reservoirs. Water isotopes showed the systematic post-seismic change in δ2H toward heavier compositions with no significant changes in the δ18O, which was interpreted as due to isotopic exchange between water and a H2-bearing gas phase (e.g., H2S, CH4, H2) entering the system. Calculated δ13C data of CO2 suggested a relatively shallow production from both plant-root respiration and microbial-driven degradation of organic matter while the almost pure crustal origin of He (R/Ra values = 0.04–0.16 from the bubbling gas phase emitted by one of the monitored wells) reasonably excludes any evidence of both primary mantle 3He degassing and ascent of heavier CO2 from deep (mantle, decarbonation) inorganic sources. Monitored waters which showed the most significant transient variations are aligned in the same E-W direction along which the seismicity and soil gas anomalies were distributed, at about 5 km S from the epicenter of the May 20th seismic event and along the main direction of the May 29th (MW = 5.8) event. This confirms that the transient variations have been activated by the seismic sequence in a sector of the crust where the presence of a fault/fracture system favors the intensification of processes affecting sediments and groundwater (variations of porosity/permeability of soils, the groundwater level, redox state, etc.) and which are able to explain the observed geochemical variations. Only one sample monitored, the one closest to the epicenter of the May 20th event, showed clear geochemical evidence suggesting the hypothesis of mixing between superimposed water bodies.
    Description: Published
    Description: 105624
    Description: 9T. Geochimica dei fluidi applicata allo studio e al monitoraggio di aree sismiche
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
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    Insights into the dynamics of the Nirano Mud Volcano through seismic characterization of drumbeat signals and V/H analysis (2022)
    Elsevier
    Details
    Publication Date: 2022-09-30
    Description: Mud volcanoes are rapidly-evolving geological phenomena characterized by the surface expulsion of sediments and fluids from over-pressurized underlying reservoirs. We investigate the Nirano Mud Volcano, Northern Italy, with seismic methods to better understand the dynamic evolution of the system and shed light on its subsurface structure. Our study allowed to detect and characterize three different types of high-frequency drumbeat signals that are present in the most active part of the mud volcano plumbing system. With a back-projection method based on the cross-correlation envelope of signals recorded at different station pairs, we can determine the source location of the drumbeats. These coincide with the location of V/H (vertical-to-horizontal) amplitude peaks obtained from an ambient vibration profile and resistivity anomalies identified in a previous study. We observe that the drumbeats are P-wave dominated signals, with characteristics similar to those found in magmatic settings, i.e. LPs (long-period signals). We suggest that such tremors originate from the migration of mud and gas inside the mud volcanic conduits. The source location, waveform and frequency content of the drumbeats evolve over time. We found that drumbeat occurrence is directly linked with morphological changes at surface.
    Description: Published
    Description: 107619
    Description: 7A. Geofisica per il monitoraggio ambientale
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
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    Geodynamics, geophysical and geochemical observations, and the role of CO2 degassing in the Apennines (2022)
    Elsevier
    Details
    Publication Date: 2022-12-01
    Description: An accurate survey of old and new datasets allowed us to probe the nature and role of fluids in the seismogenic processes of the Apennines mountain range in Italy. New datasets include the 1985–2021 instrumented seismicity catalog, the computed seismogenic thickness, and geodetic velocities and strains, whereas data from the literature comprise focal mechanism solutions, CO2 release, Moho depth, tomographic seismic velocities, heat flow and Bouguer gravity anomalies. Most of the inspected datasets highlight differences between the western and eastern domains of the Apennines, while the transition zone is marked by high geodetic strain, prevailing uplift at the surface and high seismic release, and spatially corresponds with the overlapping Tyrrhenian and Adriatic Mohos. Published tomographic models suggest the presence of a large hot asthenospheric mantle wedge which intrudes beneath the western side of the Apennines and disappears at the southern tip of the southern Apennines. This wedge modulates the thermal structure and rheology of the overlying crust as well as the melting of carbonate-rich sediments of the subducting Adriatic lithosphere. As a result, CO2-rich fluids of mantle-origin have been recognized in association with the occurrence of destructive seismic sequences in the Apennines. The stretched western domain of the Apennines is characterized by a broad pattern of emissions from CO2-rich fluids that vanishes beneath the axial belt of the chain, where fluids are instead trapped within crustal overpressurized reservoirs, favoring their involvement in the evolution of destructive seismic sequences in that region. In the Apennines, areas with high mantle He are associated with different degrees of metasomatism of the mantle wedge from north to south. Beneath the chain, the thickness and permeability of the crust control the formation of overpressurized fluid zones at depth and the seismicity is favored by extensional faults that act as high permeability pathways. This multidisciplinary study aims to contribute to our understanding of the fluid-related mechanisms of earthquake preparation, nucleation and evolution encouraging a multiparametric monitoring system of different geophysical and geochemical observables that could lead the creation of a data-constrained and reliable conceptual model of the role of fluids in the preparatory phase of earthquakes in the Apennines.
    Description: The INGV Earthquake Department Strategic Project FURTHER “The role of FlUids in the pReparaTory pHase of EaRthquakes in Southern Apennines”
    Description: Published
    Description: 104236
    Description: 1T. Struttura della Terra
    Description: 2T. Deformazione crostale attiva
    Description: 3T. Fisica dei terremoti e Sorgente Sismica
    Description: 4T. Sismicità dell'Italia
    Description: 9T. Geochimica dei fluidi applicata allo studio e al monitoraggio di aree sismiche
    Description: JCR Journal
    Keywords: CO2 Earth degassing ; Earthquakes ; Mantle wedge ; Subduction ; Apennines ; 04.06. Seismology ; Geochemistry ; 04.03. Geodesy
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 9
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    Deep fluids migration and submarine emersion of the Kalang Anyar mud volcano (Java, Indonesia): A multidisciplinary study (2023)
    Elsevier
    Details
    Publication Date: 2023-02-14
    Description: North-east Java is part of a large sedimentary basin containing hydrocarbon provinces that feature diffuse hydrothermal systems, mud volcanoes, and degassing sites. Seismic profiles acquired to explore the basin reveal a broad distribution of palaeo- and modern piercement structures. The Watukosek fault system links the volcanic arc, to the south, with the Sidoarjo province, to the north. Several piercement structures, including the Kalang Anyar mud volcano, are hosted along this left-lateral strike-slip system that favors the migration of crustal fluids in this part of the basin. Here, we present a multidisciplinary geological, geophysical and geochemical study conducted at Kalang Anyar where dozens of seepage sites are active in the crater area and intermittently emit bursts oil, gas, mud, and water. The emitted gasses are methane-dominated with smaller amounts of heavier hydrocarbons and CO2. Unlike most mud volcanoes, at Kalang Anyar the mixed-thermogenic origin of the methane is coupled with geothermal anomalies, as indicated by helium and CO2 isotopic values (δ13CCO2 as high as −4‰) that suggest the input of mantle-derived gas. Our gas flux measurements reveal that Kalang Anyar emits about 1.62 and 5.75 t yr−1 of CO2 and CH4, respectively. The intense bubbling gives rise to a typical drumbeat seismic signal characterized by dominant frequencies around of 3–4 Hz (and up to 15 Hz). We interpret the drumbeat as fluids rising and resonating through shallow plumbing system of Kalang Anyar. Erupted clasts with different lithologies and shells are scattered across the mud volcano area, while the edges of the crater zone include cubic meter-sized carbonate-cemented blocks and ridges that contain siliciclastic sediments and abundant chemosymbiotic bivalves. Carbon isotope analyses of the carbonate cement (δ13C as low as −48.8‰) identify the latter as methanogenic chemoherms. Radiocarbon (14C) dating of bivalves cemented in the blocks indicates an age of 1890-1488 BP. These results indicate that the activity of Kalang Anyar MV dates from when the area was below sea level and that the microbially-mediated precipitation of carbonates was ongoing during subaqueous methane seepage at the crater site. To the best of our knowledge, Kalang Anyar is the first example of a mud volcano that progressed from subaqueous to subaerial conditions during marine regression, displaying evidence of former marine activity (i.e. methanogenic carbonates) and current subaerial degassing at numerous seepage sites. Potentially eruptive phases represent a clear geohazard for the numerous settlements constructed inside the mud volcano. In light of this, it may be prudent to apply stricter rules for development activities, such as housing construction permits that consider the possibility of potentially catastrophic events, and apply steps to mitigate these hazards.
    Description: Published
    Description: 105970
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: mud volcano ; geochemistry ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 10
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    Antarctic permafrost degassing in Taylor Valley by extensive soil gas investigation (2023)
    Elsevier
    Details
    Publication Date: 2023-02-20
    Description: Ongoing studies conducted in northern polar regions reveal that permafrost stability plays a key role in the modern carbon cycle as it potentially stores considerable quantities of greenhouse gases. Rapid and recent warming of the Arctic permafrost is resulting in significant greenhouse gas emissions, both from physical and microbial processes. The potential impact of greenhouse gas release from the Antarctic region has not, to date, been investigated. In Antarctica, the McMurdo Dry Valleys comprise 10 % of the ice-free soil surface areas in Antarctica and like the northern polar regions are also warming albeit at a slower rate. The work presented herein examines a comprehensive sample suite of soil gas (e.g., CO2, CH4 and He) concentrations and CO2 flux measurements conducted in Taylor Valley during austral summer 2019/2020. Analytical results reveal the presence of significant concentrations of CO2, CH4 and He (up to 3.44 vol%, 18,447 ppmv and 6.49 ppmv, respectively) at the base of the active layer. When compared with the few previously obtained measurements, we observe increased CO2 flux rates (estimated CO2 emissions in the study area of 21.6 km2 ≈ 15 tons day-1). We suggest that the gas source is connected with the deep brines migrating from inland (potentially from beneath the Antarctic Ice Sheet) towards the coast beneath the permafrost layer. These data provide a baseline for future investigations aimed at monitoring the changing rate of greenhouse gas emissions from Antarctic permafrost, and the potential origin of gases, as the southern polar region warms.
    Description: Published
    Description: 161345
    Description: 6A. Geochimica per l'ambiente e geologia medica
    Description: JCR Journal
    Keywords: Antarctica; ; CO(2) output; ; McMurdo Dry Valleys; ; Permafrost; ; Soil gas survey ; 02.01. Permafrost
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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