The geological CO2 degassing history of a long-lived caldera

Alessandro Aiuppa, Pappalardo, Stefano Caliro, Aiuppa, Giovanni Chiodini

Risultato della ricerca: Article

10 Citazioni (Scopus)

Abstract

The majority of the ~100 Holocene calderas on Earth host vigorously active hydrothermal systems, the heat and volatile budgets of which are sustained by degassing of deeply stored magma. Calderas may thus contribute a nontrivial, although poorly quantified, fraction of the global budget of magmatic volatiles such as CO2. Here we use original isotopic a d petrological results from Campi Flegrei volcano, Italy, to propose that hydrothermal calcites are natural mineral archives for the magmatic CO2 that reacted with reservoir rocks during the geological history of a caldera. We show that Campi Flegrei calcites, identified in core samples extracted from 3-km-deep geothermal wells, formed at isotopic equilibrium with magmatic fluids having δ18OH2O of +8.7‰ to +12.7‰, and δ13CCO2 of ~ -1.5‰. This inferred fossil fluid composition is virtually identical to that of present-day fumaroles, demonstratinga stable carbon source duringthe caldera's (<40 k.y.) history. We use the mass of calcites stored in the hydrothermal system to estimate that 12 Gt of magmatic CO2 reacted with the Campi Flegrei rocks during the caldera history; this corresponds to a time-averaged CO2 flux of ~ 800 t d-1. This long-term CO2 flux, the first of its kind in the geological literature, is similar to the present-day soil CO2 degassing flux (1100 ± 200 t d-1). We conclude that the actual magmatic CO2 degassing flux from calderas may be severely underestimated if subsurface calcite precipitation is not taken into account.
Lingua originaleEnglish
pagine (da-a)767-770
Numero di pagine4
RivistaGeology
Volume43
Stato di pubblicazionePublished - 2015

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degassing
caldera
calcite
history
hydrothermal system
fumarole
fluid composition
reservoir rock
volcano
magma
Holocene
fossil
well
fluid
carbon
mineral
rock
soil

All Science Journal Classification (ASJC) codes

  • Geology

Cita questo

Aiuppa, A., Pappalardo, Caliro, S., Aiuppa, & Chiodini, G. (2015). The geological CO2 degassing history of a long-lived caldera. Geology, 43, 767-770.

The geological CO2 degassing history of a long-lived caldera. / Aiuppa, Alessandro; Pappalardo; Caliro, Stefano; Aiuppa; Chiodini, Giovanni.

In: Geology, Vol. 43, 2015, pag. 767-770.

Risultato della ricerca: Article

Aiuppa, A, Pappalardo, Caliro, S, Aiuppa & Chiodini, G 2015, 'The geological CO2 degassing history of a long-lived caldera', Geology, vol. 43, pagg. 767-770.
Aiuppa A, Pappalardo, Caliro S, Aiuppa, Chiodini G. The geological CO2 degassing history of a long-lived caldera. Geology. 2015;43:767-770.
Aiuppa, Alessandro ; Pappalardo ; Caliro, Stefano ; Aiuppa ; Chiodini, Giovanni. / The geological CO2 degassing history of a long-lived caldera. In: Geology. 2015 ; Vol. 43. pagg. 767-770.
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