Global-scale control of extensional tectonics on CO2 earth degassing

Abstract

Earth degassing of CO2-rich fluids has been proven to contribute significantly to the global carbon budget. The presence of ubiquitous outgassing reveals some degree of permeability of the crust that often coincides with seismically active zones. In this study, we took advantage of the most recent global geological datasets to better understand earth degassing and how it correlates with tectonic regimes. Here we use an ad hoc point pattern analysis to show that there is a spatial correlation between CO2 discharges and the presence of active fault systems, in particular with those characterized by a normal slip type. Seismic data demonstrate the existence of a positive spatial correlation between gas discharges and extensional tectonic regimes and confirms that such processes would play a key role in creating pathways for the rising gases at micro- and macro-scales, increasing the rock permeability and connecting the deep crust to the earth surface.

Volcanic Gas Emissions Along the Colombian Arc Segment of the Northern Volcanic Zone (CAS‐NVZ): Implications for volcano monitoring and volatile budget of the Andean Volcanic Belt

“…This mismatch between C inputs at trench and C outputs at the Colombian trench is most likely larger if considering other C sources, as discussed above. However, our reports contribute additional information to earlier calculations made for other arc segments (e.g., de Moor et al, ; Hilton et al, ) and implies (i) a limited C recycling efficiency in the slab (due to high slab carbonate stability (see recent discussion by Keleman &Manning, 2013); (ii) that C is primarily recycled by forms of degassing other than plumes/fumaroles at central volcanoes (e.g., soils and/or groundwater; Chiodini et al, ; Tamburello et al, ); or (iii) that significant carbon sequestration occurs in the forearc crust, as suggested by Barry et al ().…”

AGU Centennial Grand Challenge: Volcanoes and Deep Carbon Global CO2 Emissions From Subaerial Volcanism—Recent Progress and Future Challenges

“…One general conclusion is that characterizing the carbon isotope signature of soil CO 2 (Chiodini et al, ) should be prioritized in future soil degassing surveys, as it would be key to better resolving the volcanic versus biogenic contributions. One additional challenge will be to identify techniques to resolve, in large volcanic provinces such as the East African Rift, the fraction of deep CO 2 that is magma sourced from that derived by tectonic degassing (e.g., mantle and metamorphic degassing): the two contributions may spatially overlap at sites (Tamburello et al, ) and may be difficult to resolve isotopically. Ultimately, any future attempt to refine estimates of the global diffuse CO 2 output will have to rely on a more robust and comprehensive data set than available today and on more accurate global quantification of the number of volcanoes that are actively degassing CO 2 in diffuse form.…”

Structural architecture releasing deep-sourced carbon dioxide diffuse degassing at the Caviahue – Copahue Volcanic Complex

“…As explained in the introduction, Tamburello et al (2018) have stated that extensional tectonics and, in particular, normal and strikeslip faults constitute the most suitable scenario for CO 2 to rise to the surface. The findings of this study are in good agreement with this premise, and they also suggest that areas with higher structural damage play a key role on the localization of CO 2 diffuse anomalies.…”

“…It is now well established from a variety of studies that faults and fractures play a key role in the localization and evolution of hydrothermal systems (Sibson, 1996;Curewitz and Karson, 1997;Sibson and Rowland, 2003;Fairley and Hinds, 2004;Faulkner et al, 2010;Dockrill and Shipton, 2010;Rowland and Simmons, 2012;Faulds et al, 2013;Fossen and Rotevatn, 2016;Tardani et al, 2016). Recent studies from Tamburello et al (2018) have carried out a global point pattern analysis and have stated there is a positive spatial correlation between CO 2 -rich gas discharges and extensional tectonic regimes. These authors affirm that extensional scenarios play a key role in creating pathways for deep-sourced CO 2 at micro-and macro-scales.…”