Remobilization of crustal carbon may dominate volcanic arc emissions

Abstract

The flux of carbon into and out of Earth's surface environment has implications for Earth's climate and habitability. We compiled a global data set for carbon and helium isotopes from volcanic arcs and demonstrated that the carbon isotope composition of mean global volcanic gas is considerably heavier, at -3.8 to -4.6 per mil (‰), than the canonical mid-ocean ridge basalt value of -6.0‰. The largest volcanic emitters outgas carbon with higher δC and are located in mature continental arcs that have accreted carbonate platforms, indicating that reworking of crustal limestone is an important source of volcanic carbon. The fractional burial of organic carbon is lower than traditionally determined from a global carbon isotope mass balance and may have varied over geological time, modulated by supercontinent formation and breakup.

Noble Gas and Carbon Isotope Systematics at the Seemingly Inactive Ciomadul Volcano (Eastern‐Central Europe, Romania): Evidence for Volcanic Degassing

“…Allard et al (1991), and Edmonds (2008) pointed out that stronger degassing around the volcanic edifice is not uncommon in volcanic regions. Data on individual volcanoes worldwide are based on the compilation of Mason et al (2017), by Allard (1983), Marty and Giggenbach (1990), Poorter et al (1991), Varekamp et al (1992), Sturchio et al (1993), Sano et al (1994), Sano and Marty (1995), Tedesco et al (1995), Hilton (1996), Sano and Williams (1996), Allard et al (1997), Fischer et al (1998), van Soest et al (1998), Pedroni et al (1999, Lewicki et al (2000), Parello et al (2000), Favara et al (2001), Snyder et al (2001), Shaw et al (2003), Symonds et al (2003) Indeed, the occurrence of high-Mg minerals, such as olivine, clinopyroxene, and orthopyroxene in the dacites (Kiss et al, 2014;Vinkler et al, 2007) suggests that mafic magma also played an important role in the magma evolution.…”

“…This high magmatic He content of the gases is not unique and resembles what Trasatti et al (2018) proposed for Colli Albani volcanic complex, another long-dormant volcanic field, where they assumed more than 80% mantle-derived component in the emitted CO 2 gases. Data on individual volcanoes worldwide are based on the compilation of Mason et al (2017) from the data presented by Allard (1983), Marty and Giggenbach (1990), Poorter et al (1991), Varekamp et al (1992), Sturchio et al (1993), Sano et al (1994), Sano and Marty (1995), Tedesco et al (1995), Hilton (1996), Sano and Williams (1996), Allard et al (1997), Fischer et al (1998), van Soest et al (1998, Pedroni et al (1999), Lewicki et al (2000), Parello et al (2000), (Ciotoli et al, 2013) plotting He isotopic ratios (R/R a ) versus 13 C CO2 (VPDB) of Ciomadul gas emissions.…”

Implementation of electrochemical, optical and denuder-based sensors and sampling techniques on UAV for volcanic gas measurements: examples from Masaya, Turrialba and Stromboli volcanoes

“…Changes in the magma degassing behavior and/or the hydrothermal systems beneath volcanoes generally influence the gas composition and gas fluxes. Measuring the emitted gas composition can provide crucial information on understanding subsurface processes related to activity changes (e.g., Allard et al, 1991;Aiuppa et al, 2007;Bobrowski and Giuffrida, 2012;de Moor et al, 2016a;Liotta et al, 2017) and help to estimate fluxes of the geological carbon cycle (e.g., Burton et al, 2013;Mason et al, 2017) and tectonic processes controlling volcanic degassing (e.g., Aiuppa et al, 2017;de Moor et al 2017). In the field of volcanic monitoring, the observation of gas composition changes has become an important tool for detecting precursory processes for volcanic eruptions.…”

Evolution of the Global Carbon Cycle and Climate Regulation on Earth

“…However, there is work suggesting that arc magmas may be more CO 2 rich than previously hought, and that the arc volcanic CO 2 flux may be correspondingly higher (Blundy et al, ). A large portion of the carbon emitted by these volcanoes may be derived from reworking of crustal carbonate rocks in the upper plate (Mason et al, ). Further, metamorphism in contact aureoles around magmatic intrusions also drives decarbonation reactions (D'Errico et al, ; Lee et al, ).…”