Areas found at plate boundaries are characterized by the presence of seismic, volcanic and geothermal activity. 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. Certainly not limited to plate boundaries, as magma rises from depth, decreasing pressure allows volatile species to partition to the gas phase. Bubbles form, grow, coalesce and gases start to flow through vesiculated magma. Eventually, fluids escape towards the surface using tectonic structures and are released in the atmosphere, in some cases diffused through a soil or bubbling through a water pool, in other cases forming large plumes or explosive eruption columns. Fluids play an important role in earthquake generation.
Geochemical and isotope composition of gases deriving from different settings can trace sources and chemical and physical processes, providing information about deep earth. Moreover, volatiles play a key role in magma transport and have significant impact on the style and timing of volcanic eruptions. In addition, noble gases deriving from the deep earth can provide important information about their crust or mantle origin because these gases hardly react with other materials during migration. While carbon dioxide is one of the major constituents in volcanic/geothermal areas, methane, dominating sedimentary low heat flow areas, is often linked to subsurface hydrocarbon reservoirs that due to tectonic discontinuities are released in the atmosphere. Furthermore, sulfur dioxide emissions that take place in volcanic environments can cause acid rain, influence aerosol formation and, if an eruption column reaches the stratosphere, cause global dimming and a decrease in Earth’s surface temperatures for years. Similarly, halogens can dramatically impact proximal ecosystems, influence the oxidation capacity of the troposphere and alter the stratospheric ozone layer. Gas composition and flux may change with time, reflecting variations in the system. Measuring gases therefore constitutes a powerful tool for monitoring and understanding Earth.
This session aims to merge different geo-disciplines and bring together researchers interested in the comprehension of the degassing processes that take place in various geodynamic regimes. Furthermore, identify the impact that the emissions can have on terrestrial environment, atmospheric composition, climate and human health at various temporal and spatial scales. We invite contributions discussing novel measurement techniques, field measurements, direct and remote ground- and space-based observations and modeling studies of degassing can provide new insights into volcanic, tectonic and atmospheric processes on local and global scales.