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  • 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases  (10)
  • Elsevier Ltd.  (9)
  • Copernicus  (1)
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  • 1
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    Terrestrial methane seeps and mud volcanoes: A global perspective of gas origin (2009)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: A global database of gas composition and methane stable isotopes of 143 terrestrial mud volcanoes from 12 countries and 60 seeps independent from mud volcanism from eight countries, was compiled and examined in order to provide the first worldwide statistics on the origin of methane seeping at the earth’s surface. Sixteen seep data were coupled with their associated subsurface reservoirs. The surface seepage data indicate that at least 76% of the mud volcanoes release thermogenic gas, with only 4% biogenic and 20% with mixed character. The average (201 data) of methane concentration and methane carbon isotope ratios (δ to the power of 13 C1) of mud volcanoes are 90% v/v and -46.4‰, respectively. The other types of seeps, which are independent from mud volcanism, have an average δ to the power of 13 C1 value that is slightly higher (-42.9‰). Gases from mud volcanoes are generally lighter (more methane, less ethane and propane) than their associated reservoir gases, suggesting a molecular fractionation during advective fluid migration. Other types of seeps, especially "dry" seeps, maintain the reservoir C1/(C2 + C3) "Bernard" ratio. Mud volcanoes behave like a "natural refinery" and the origin of gas more isotopically enriched than -50% and with C1/(C2 + C3) 〉500 should be attributed to a thermogenic source, rather than partial oxidation of biogenic gas. Some data that appear biogenic in the "Bernard diagram" can be explained by molecular fractionation of mixed gas. Consequently, the "Bernard" parameter may be misleading when applied to mud volcanoes since it does not always reflect the original gas composition. The mechanisms of the molecular advective segregation should be studied quantitatively by specific models and experiments.
    Description: Published
    Description: 333-344
    Description: 3.8. Geofisica per l'ambiente
    Description: JCR Journal
    Description: reserved
    Keywords: Mud volcanoes ; Seeps ; Methane ; Isotopes ; Organic geochemistry ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    Shallow seep-related seafloor features along the Malta plateau (Sicily channel – Mediterranean Sea): Morphologies and geo-environmental control of their distribution (2009)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: Between 140 and 170 m water depth, more than 100 small-scale domes and peculiar ridges were mapped a few miles offshore of south-eastern Sicily along the Malta plateau (eastern Mediterranean Sea), Swath bathymetric data along with a dense grid of side scan sonar and seismic profiles were acquired in an area extending over 100 km2. Gravity cores, water samples and video observations were also collected at selected sites. Mapped domes were found from 50 to 200 m wide and no more than 5 m high occurring on the seafloor, isolated or arranged in clusters. Ridges consisted of large tabular sub-elongated structures, elevated from 5 to 10 m from the surrounding seafloor, and had flat tops on which numerous closeset, small cones occurred, appearing in video observation as carbonate buildings strongly colonized by gorgonians. Characteristic acoustic signatures (i.e. blank areas and/or turbidity zones and enhanced reflections in seismic records), measured gas anomalies in seawater samples and detected plumes on echosounder profiles suggest that both the domes and ridges are influenced by active seeps. In addition, their spatial distribution reflected patterns of tectonic lineaments produced by the late Miocene to present-day geo-dynamic evolution of the Malta plateau, which is also an important hydrocarbon province. Results from gravity cores suggest that mud extrusion seems to be the main process responsible for the origin of the domes, which are formed by gray mud with only a few centimeters of biogenic sand at the top, indicating that recent bioclastic material is not a major contributor to mound building. However, at present, active degassing appears to be the main process that controls the morphological and sedimentological expression of both the domes and ridges. Therefore, a quiescent or intermittent active stage for mud extrusion is considered.
    Description: Published
    Description: 1831-1848
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Methane seeps ; Mud extrusion ; Seismic ; Backscattering ; Seafloor morphology ; Malta plateau ; Sicily channel ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
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    Estimation of the magmatic gas and heat flux through the Etnean volcanic aquifer (2010)
    Copernicus
    Details
    Publication Date: 2017-04-04
    Description: Etna volcano, Italy, hosts one of the major groundwater systems of the island of Sicily. Waters circulate within highly permeable fractured, mainly hawaiitic, volcanic rocks. Aquifers are limited downwards by the underlying impermeable sedimentary terrains. Thickness of the volcanic rocks generally does not exceed some 300 m, preventing the waters to reach great depths. This is faced by short travel times (years to tens of years) and low thermalisation of the Etnean groundwaters. Measured temperatures are, in fact, generally lower than 25 °C. But the huge annual meteoric recharge (about 0.97 kmˆ3) with a high actual infiltration coefficient (0.75) implies a great underground circulation. During their travel from the summit area to the periphery of the volcano, waters acquire magmatic heat together with volcanic gases and solutes through water-rock interaction processes. In the last 20 years the Etnean aquifers has been extensively studied. Their waters were analysed for dissolved major, minor and trace element, O, H, C, S, B, Sr and He isotopes, and dissolved gas composition. These data have been published in several articles. Here, after a summary of the obtained results, the estimation of the magmatic heat flux through the aquifer will be discussed. To calculate heat uptake during subsurface circulation, for each sampling point (spring, well or drainage gallery) the following data have been considered: flow rate, water temperature, and oxygen isotopic composition. The latter was used to calculate the mean recharge altitude through the measured local isotopic lapse rate. Mean recharge temperatures, weighted for rain amount throughout the year, were obtained from the local weather station network. Calculations were made for a representative number of sampling points (216) including all major issues and corresponding to a total water flow of about 0.315 kmˆ3/a, which is 40% of the effective meteoric recharge. Results gave a total energy output of about 140 MW/a the half of which is ascribable to only 13 sampling points. These correspond to the highest flow drainage galleries with fluxes ranging from 50 to 1000 l/s and wells with pumping rates from 70 to 250 l/s. Geographical distribution indicates that, like magmatic gas leakage, heat flow is influenced by structural features of the volcanic edifice. The major heat discharge through groundwater are all tightly connected either to the major regional tectonic systems or to the major volcanic rift zones along which the most important flank eruptions take place. But rift zones are much more important for heat upraise due to the frequent dikes injection than for gas escape because generally when dikes have been emplaced the structure is no more permeable to gases because it becomes sealed by the cooling magma.
    Description: Published
    Description: Vienna, Austria
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: open
    Keywords: groundwaters ; volcanic surveillance ; water chemistry ; dissolved gases ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 03. Hydrosphere::03.04. Chemical and biological::03.04.03. Chemistry of waters ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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  • 4
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    ‘‘Pieve Santo Stefano’’ is not a mud volcano: Comment on ‘‘Structural controls on a carbon dioxide-driven mud volcano field in the Northern Apennines’’ (by Bonini, 2009) (2009)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: Bonini (2009) has recently written an interesting paper dealing with the structural setting and relationships to seismicity of a CO2(carbon dioxide)-driven mud volcano, called Pieve S. Stefano (PSS), located in the Northern Apennines of Italy.We outline here that PSS is not a mud volcano at all. The author erroneously attributes the term ‘‘mud volcano’’ (also featured in the title of the article) to a CO2-dominant gas manifestation, which should be considered as a ‘‘mofette’’ or more generally a dry CO2-vent (or ‘‘gas pool’’; Minissale et al., 2000; Heinicke et al., 2006). Our comment does not dispute Bonini’s data interpretations and conclusions (for which a first comment has already been made by Collettini, in press), but discusses why misuse of the term ‘‘mud volcano’’ may lead to misquotations in future mud volcano literature.
    Description: Published
    Description: 1270-1271
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Mud volcano ; Mofette ; Carbon dioxide ; Gas manifestation ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
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    Comparison between different methodologies for detecting Radon in soil along an active fault: the case of the Pernicana fault system, Mt. Etna (Italy) (2009)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: Three different methodologies were used to measure Radon (222Rn) in soil, based on both passive and active detection system. The first technique consisted of Solid State Nuclear Track Detectors (SSNTD), CR-39 type, and allowed integrated measurements. The second one consisted of a portable device for short time measurements. The last consisted of a continuous measurement device for extended monitoring, placed in selected sites. Soil 222Rn activity was measured together with soil Thoron (220Rn) and soil carbon dioxide (CO2) efflux, and it was compared with the content of radionuclides in the rocks. Two different soil gas horizontal transects were investigated across the Pernicana fault system (NE flank of Mount Etna), from November 2006 to April 2007. The results obtained with the three methodologies are in a general agreement with each other and reflect the tectonic settings of the investigated study area. The lowest 222Rn values were recorded just on the fault plane, and relatively higher values were recorded a few tens of meters from the fault axis on both of its sides. This pattern could be explained as a dilution effect resulting from high rates of soil CO2 efflux. Time variations of 222Rn activity were mostly linked to atmospheric influences, whereas no significant correlation with the volcanic activity was observed. In order to further investigate regional radon distributions, spot measurements were made to identify sites having high Rn emissions that could subsequently be monitored for temporal radon variations.. SSNTD measurements allow for extended-duration monitoring of a relatively large number of sites, although with some loss of temporal resolution due to their long integration time. Continuous monitoring probes are optimal for detailed time monitoring, but because of their expense, they can best be used to complement the information acquired with SSNTD in a network of monitored sites..
    Description: Work founded by Istututo Nazionale di Geofisica e Vulcanologia and Dipartimento Protezione Civile, Italy
    Description: Published
    Description: 178-185
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: JCR Journal
    Description: reserved
    Keywords: Soil Radon and Thoron activity ; soil CO2 efflux ; Pernicana fault system ; volcano-tectonic monitoring ; Mount Etna ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.07. Radioactivity and isotopes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.06. Rheology, friction, and structure of fault zones ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 05. General::05.09. Miscellaneous::05.09.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 6
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    Natural emissions of methane from geological seepage in Europe (2009)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: Recent studies have shown that geological emissions of methane are an important greenhouse-gas source. Remarkable amounts of methane, estimated in the order of 40-60 Tg yr-1, are naturally released into the atmosphere from the Earth’s crust through faults and fractured rocks. The main source is natural gas, both microbial and thermogenic, produced in hydrocarbon-prone sedimentary basins and injected into the atmosphere through macro-seeps (onshore and offshore mud volcanoes and other seeps) and microseepage, an invisible but pervasive flux from the soil. This source is now evaluated for Europe on the basis of a literature survey, new field measurements and derived emission factors. The up-scaling criteria recommended by the EMEP/CORINAIR guidelines are applied to the local point and area source data. In Europe, 25 countries host oil and/or natural gas reservoirs and potentially, or actually, emit geological methane. Flux data, however, are available only from 10 countries: the onshore or offshore petroliferous sectors of Denmark, Italy, Greece, Romania, Spain, Switzerland, United Kingdom and Black Sea countries (Bulgaria, Ukraine, Georgia). Azerbaijan, whose emissions due to mud volcanism are known to be relevant, is included in the estimate. The sum of emissions, regional estimates and local measurements, related to macro-seeps leads to a conservative total value of about 2.2 Tg yr-1. Together with the potential microseepage fluxes from the petroliferous basins, estimated on the basis of the Total Petroleum System concept (around 0.8 Tg yr-1), the total European seepage is projected to 3 Tg yr-1. This preliminary figure would represent, in terms of magnitude, the second natural methane source for Europe after wetlands. The estimate will have to be refined by increasing the number of seepage measurements both on lands, where there is high potential for microseepage (e.g., Germany, Hungary, Romania, Ukraine, Belarus, Russia, Georgia) and in coastal marine areas (the North Sea, the Black Sea, offshore Greece and Italy) where emission factors and the extent of the underwater seeping area are not completely known.
    Description: Published
    Description: 1430-1443
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Methane ; Natural emissions ; Geological sources ; Seepage ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 7
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    Deep-sea survey for the detection of methane at the ‘‘Santa Maria di Leuca’’ cold-water coral mounds ( Ionian Sea, South Italy) (2010)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: The ‘‘Santa Maria di Leuca" Cold-Water Coral (CWC) province (northern Ionian Sea) was investigated for the first time to detect eventual occurrence of methane anomalies as a possible indication of hydrocarbon seepage stimulating the coral growth. Most coral mounds have developed in correspondence with tectonic scarps and faults, orthogonal to the southern margin and trending NW-SE, which could be potential sites of gas escape. A visual and instrumental inspection was performed by using a new deep-sea probe equipped with video-cameras, sonar, CTD, methane sensors, and a water sampler. Eight areas were explored by 10 surveys, depths ranging from 380 to 1100 m, for a total of more than 26h of continuous video and instrumental recording. Sediments were also sampled by gravity corers and analysed in laboratory. The images allowed to assess distribution, abundance and geometry of the colonies, most of which are developed on morphological highs often characterised by tectonic scarps. All data indicate however the lack of a significant occurrence of methane, both in seawater and sediments. No direct or indirect expressions of gas seepage were recognised on the seabed. Weak methane anomalies were detected only in seawater at the base of some fault-linked scarps, where more reducing conditions and bacterial methanogenesis are possibly enhanced by less water circulation. The faults are not fluid-bearing as previously suggested by high-resolution geophysical signatures. The development of the coral colonies thus cannot be attributed to seeping fluids, but to a favourable physiographic position with exposure to nutrient-rich currents.
    Description: In press
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Methane ; Corals ; Seepage ; Marine geology ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 8
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    Benthic habitat characterization and distribution from two representative sites of the deep-water SML Coral Province (Mediterranean) (2010)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: Two sites (MS04 and MS06) from the Santa Maria di Leuca (SML) Coral Province were analyzed by a video and acoustic survey during the National Italian Project Apulian Plateau Bank Ecosystem Study (APLABES). Site MS04 (Atlantis Mound) is characterized by a sub-conical mound, 500 m wide and 25 m high, located at a water depth of about 650 m. Site MS06 (Yellow Chain)comprises several elongated reliefs (NNW–SSE-oriented), up to 25 m high and 500 m in maximum lateral extent, located at a depth of between 490 and 540 m. At both sites, two main mesohabitats (mound and intermound) containing several coral-bearing and-barren macrohabitats were observed in recorded videos and detected in side- scan sonographs. The coral-rich macrohabitats, characterized by densely packed colonies of the scleractinians Madrepora oculata and, secondarily, Lophelia pertusa (M/L), are typically restricted to the mound areas. The mud-dominated ones, almost devoid of M/L colonies, are more common within the intermound mesohabitat. However, on the most extensive mounds, both macrohabitat typologies exist. They are heterogeneously distributed on the mound surface, often showing a clear differentiation along two opposite flanks of the same topographic feature. M/L-rich macrohabitats are preferentially located on top and along the mound northeastern flank, showing a typical step-like distribution, probably reflecting the arrangement of hard substrate outcrops. Along this flank, fan-shaped Madrepora colonies and sponges are often oriented NNW–SSE, implying, together with other evidence, a primary southwestern current flow. The hard-bottom macrohabitats of the southwestern mound flank are generally restricted to sparse exposed, subvertical to overhanging scarps as well as to heterometric boulders located at the scarp base. Their fauna is mainly characterized by small-sized organisms (such as sponges and solitary scleractinians although m-sized boulders may locally host very large antipatharian colonies (Leiopathes glaberrima). The heterogeneous distribution of the observed benthic macrohabitats seems to be strictly related to the local topography, the main current flow (and consequently larvae/food supply per unit of time), and the substrate typology (hard-vs. soft-bottom).
    Description: In press
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Deep-water coral mound ; Habitat ; Mediterranean ; Madrepora ; Lophelia ; Visual survey ; Acoustic survey ; 03. Hydrosphere::03.04. Chemical and biological::03.04.02. Carbon cycling ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 9
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    Spatial distribution of soil radon as a tool to recognize active faulting on an active volcano: the example of Mt. Etna (Italy) (2011)
    Elsevier Ltd.
    Details
    Publication Date: 2017-04-04
    Description: This study concerns measurements of radon and thoron emissions from soil carried out in 2004 on the eastern flank of Mt. Etna, in a zone characterized by the presence of numerous seismogenic and aseismic faults. The statistical treatment of the geochemical data allowed recognizing anomaly thresholds for both parameters and producing distribution maps that highlighted a significant spatial correlation between soil gas anomalies and tectonic lineaments. The seismic activity occurring in and around the study area during 2004 was analyzed, producing maps of hypocentral depth and released seismic energy. Both radon and thoron anomalies were located in areas affected by relatively deep (5e10 km depth) seismic activity, while less evident correlation was found between soil gas anomalies and the released seismic energy. This study confirms that mapping the distribution of radon and thoron in soil gas can reveal hidden faults buried by recent soil cover or faults that are not clearly visible at the surface. The correlation between soil gas data and earthquakes depth and intensity can give some hints on the source of gas and/or on fault dynamics.
    Description: Published
    Description: 863-870
    Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 3.1. Fisica dei terremoti
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: radon ; fault ; seismic hazard ; Etna ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.07. Radioactivity and isotopes ; 03. Hydrosphere::03.04. Chemical and biological::03.04.08. Instruments and techniques ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 10
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    Evidence of subsurface anaerobic biodegradation of hydrocarbons and potential secondary methanogenesis in terrestrial mud volcanoes (2009)
    Elsevier Ltd.
    Details
    Publication Date: 2022-02-16
    Description: The assessment of gas origin in mud volcanoes and related petroleum systems must consider postgenetic processes which may alter the original molecular and isotopic composition of reservoir gas. Beyond eventual molecular and isotopic fractionation due to gas migration and microbial oxidation, investigated in previous studies, we now demonstrate that mud volcanoes can show signals of anaerobic biodegradation of natural gas and oil in the subsurface. A large set of gas geochemical data from more than 150 terrestrial mud volcanoes worldwide has been examined. Due to the very low amount of C2+ in mud volcanoes, isotopic ratios of ethane, propane and butane (generally the best tracers of anaerobic biodegradation) are only available in a few cases. However, it is observed that 13C-enriched propane is always associated with positive б13 CCO2 values, which are known indicators of secondary methanogenesis following anaerobic biodegradation of petroleum. Data from carbon isotopic ratio of CO2 are available for 134 onshore mud volcanoes from 9 countries (Azerbaijan, Georgia, Ukraine, Russia, Turkmenistan, Trinidad, Italy, Japan and Taiwan). Exactly 50% of mud volcanoes, all releasing thermogenic or mixed methane, show at least one sample with б13 CCO2〉+5‰ (PDB). Thermogenic CH4 associated with positive carbon isotopic ratio of CO2 generally maintains its б13C-enriched signature, which is therefore not perturbed by the lighter secondary microbial gas. There is, however, high variability in the б13 CCO2 values within the same mud volcanoes, so that positive б13 CCO2 values can be found in some vents and not in others, or not continuously in the same vent. This can be due to high sensitivity of б13 CCO2 to gas–water–rock interactions or to the presence of differently biodegraded seepage systems in the same mud volcano. However, finding a positive б13 CCO2 value should be considered highly indicative of anaerobic biodegradation and further analyses should be made, especially if mud volcanoes are to be used as pathfinders of the conditions indicative of subsurface hydrocarbon accumulations in unexplored areas.
    Description: Published
    Description: 1692-1703
    Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi
    Description: JCR Journal
    Description: reserved
    Keywords: Mud volcanoes ; Methane ; Secondary methanogenesis ; Anaerobic biodegradation ; Isotopically enriched CO2 ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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