Search results for "Degas"

Preliminary study on geogenic degassing through the big karstic aquifers of Greece

2019

Non-volcanic degassing contributes to the C-cycle by providing on a global scale a significant amount of CO2 emitted through diffuse earth degassing processes (Kerrick et al 1995). Due to the elevated solubility of the CO2 in water, in the areas where high CO2 fluxes directly affect regional aquifers, most of it can be dissolved, transported and released by groundwaters. Therefore, quantification of this contribution to the atmosphere has a substantial implication for modeling the global carbon cycle. According to Chiodini et al. (2000), total dissolved inorganic carbon (TDIC) concentrations and δ13CTDIC values of groundwaters are useful tools to both quantify the geogenic degassing and dis…

"Hidden” degassing from streams: estimation of the CO2 release from the thermal springs of Sperchios Basin, Greece

2019

Areas located at plate boundaries are characterized by the presence of seismic, volcanic, and geothermal activity, as well as ore deposition. Such processes are enhanced by the circulation of hydrothermal fluids in the crust transporting volatiles from either the deep crust or the mantle to the surface. Intense geodynamic activity is also taking place in Greece giving rise to: (i) the highest seismicity in Europe, (ii) the presence of an active volcanic arc and numerous areas of anomalously high geothermal gradient, and (iii) a widespread occurrence of thermal springs. Elevated heat flow values are concentrated in Sperchios basin, an area characterised by a system of deeply rooted extension…

Estimation of CO2 release from thermal springs to the atmosphere

2019

Introduction Geodynamically active regions have long been recognized as areas of anomalous Earth degassing [Irwin and Barnes, 1980]. Areas found at plate boundaries are characterized by seismic, volcanic and geothermal activity as well as ore deposition. These processes are enhanced by the circulation of hydrothermal fluids in the crust, which transport volatiles from the deep crust or mantle to the surface [King, 1986]. Kerrick and Caldera, [1998], were the first to indicate the significant contribution of the CO2 degassing by extensional tectonic and hydrothermal activity in metamorphic belts during the Phanerozoic. Moreover, further studies concerning gas emissions from diffuse degassing…

Carbon degassing through karst hydrosystems of Greece

2022

Estimation of CO2 degassing from active tectonic structures and regional hydrothermal systems is essential for the quantification of presentday Earth degassing [Frondini et al., 2019 and references therein]. Due to the high solubility of CO2 in water, great amounts of deep inorganic carbon can be dissolved, transported, and released from regional aquifers. By applying a massbalance approach [Chiodini et al., 2000], different sources of the dissolved CO2 can be discriminated. The main source of degassing in Greece is concentrated in hydrothermal and volcanic areas. However, deep CO2 from active tectonic areas has not yet been quantified. A key point of this research is to investigate the pos…

Steam and gas emission rates from La Soufrière of Guadeloupe (Antilles arc): implications for the magmatic supply degassing during unrest

2015

Since its last magmatic eruption in 1530 AD, La Soufrière andesitic volcano in Guadeloupe has displayed intense hydrothermal activity and six phreatic eruptive crises (the last of which, in 1976-1977, with 73000 evacuees). Here we report on the first direct quantification of gas plume emissions from La Soufrière summit vents, which gradually intensified during the past 20 years. Gas fluxes were determined in 2006 then 2012 [1] by measuring the horizontal and vertical distribution of volcanic gas concentrations in the air-diluted plume, the composition of the hot fumarolic fluid at exit (108°C), and scaling to the speed of plume transport (in situ measurements and FLIR imaging). We first dem…

Active geodynamic in the central Mediterranean: Transfer of mantle fluids across the north-eastern Sicily

2019

Outgassing of mantle fluids across an tectonically active crustal segment in between two volcanic systems (Etna and Aeolian arc): the Nebrodi-Pelorit…

2018

Mantle-degassing occurs primarily through active volcanic systems and young oceanic lithosphere. Mantle-volatiles are also released by tectonically active continental regions, but the magnitude of this phenomenon is far less characterised. Helium (He) is a powerful tracer to track deep volatile degassing, because the mantle contains more 3He than the crust/atmosphere systems, which are dominated by radiogenic 4He produced in the crust. Here, we studied the volatiles in thermal manifestations discharged along the Nebrodi- Peloritani chain in north-eastern Sicily, with the aim of investigating the origin of thermalism and the related fluids. Thisseismically active region connects the African-…

Total (fumarolic + diffuse soil) CO2 output from Furnas volcano

2015

Furnas volcano, in São Miguel island (Azores), being the surface expression of rising hydrothermal steam, is the site of intense carbon dioxide (CO2) release by diffuse degassing and fumaroles. While the diffusive CO2 output has long (since the early 1990s) been characterized by soil CO2 surveys, no information is presently available on the fumarolic CO2 output. Here, we performed (in August 2014) a study in which soil CO2 degassing survey was combined for the first time with the measurement of the fumarolic CO2 flux. The results were achieved by using a GasFinder 2.0 tunable diode laser. Our measurements were performed in two degassing sites at Furnas volcano (Furnas Lake and Furnas Villag…

Volcanic gas emissions and degassing dynamics at Ubinas and Sabancaya volcanoes; implications for the volatile budget of the central volcanic zone

2017

Abstract Emission of volcanic gas is thought to be the dominant process by which volatiles transit from the deep earth to the atmosphere. Volcanic gas emissions, remain poorly constrained, and volcanoes of Peru are entirely absent from the current global dataset. In Peru, Sabancaya and Ubinas volcanoes are by far the largest sources of volcanic gas. Here, we report the first measurements of the compositions and fluxes of volcanic gases emitted from these volcanoes. The measurements were acquired in November 2015. We determined an average SO 2 flux of 15.3 ± 2.3 kg s − 1 (1325-ton day − 1 ) at Sabancaya and of 11.4 ± 3.9 kg s − 1 (988-ton day − 1 ) at Ubinas using scanning ultraviolet spectr…

Hydrogen emissions from Erebus volcano, Antarctica

2012

International audience; The continuous measurement of molecular hydrogen (H2) emissions from passively degassing volcanoes has recently been made possible using a new generation of low-cost electrochemical sensors. We have used such sensors to measure H2, along with SO2, H2O and CO2, in the gas and aerosol plume emitted from the phonolite lava lake at Erebus volcano, Antarctica. The measurements were made at the crater rim between December 2010 and January 2011. Combined with measurements of the long-term SO2 emission rate for Erebus, they indicate a characteristic H2 flux of 0.03 kg s-1 (2.8 Mg day-1). The observed H2 content in the plume is consistent with previous estimates of redox cond…