Reference : A review of the geology and origin of CO2 in mineral water springs in east Belgium
Scientific journals : Article
Engineering, computing & technology : Geological, petroleum & mining engineering
A review of the geology and origin of CO2 in mineral water springs in east Belgium
Barros, Renatat mailto []
Defourny, Agathe mailto [Université de Liège - ULiège > > UEE >]
Dassargues, Alain mailto [Université de Liège - ULiège > Département ArGEnCo > Hydrogéologie & Géologie de l'environnement >]
Piessens, Kris []
Welkenhuysen, Kris []
Collignon, Arnaud mailto []
Jobé, Patrick mailto []
Geologica Belgica
Geologica Belgica
Yes (verified by ORBi)
[en] CO2-rich waters ; geogenic CO2 ; Stavelot-Venn Massif
[en] Naturally CO2-rich mineral water springs (pouhons) in east Belgium occur in the context of the Rhenohercynian domain of the Variscan fold-and-thrust belt, mostly within the Cambro-Ordovician Stavelot-Venn Massif. The origin of the CO2 is still unclear, although different hypotheses exist. In this review study, we show pouhon waters are of the calcium bicarbonate type (~310 mg/l HCO3- on average), with notable Fe (~15 mg/l) and some Ca (~43 mg/l). Pouhon waters are primarily meteoric waters, as evidenced by H and O isotopic signature. The δ13C of CO2 varies from -7.8 to +0.8‰ and contains up to ~15% He from magmatic origin, reflecting a combination of carbonate rocks and mantle as CO2 sources at depth. Dinantian and Middle Devonian carbonates at 2–6 km depth could be potential sources, with CO2 generated by dissolution. However, carbonates below the Stavelot-Venn Massif are only predicted by structural models that assume in-sequence thrusting, not by the more generally accepted out-of-sequence thrust models. The mantle CO2 might originate from degassing of the Eifel magmatic plume or an unknown shallower magmatic reservoir. Deep rooted faults are thought to act as preferential pathways. Overall low temperatures of pouhons (~10 °C) and short estimated residence times (up to 60 years) suggest magmatic CO2 is transported upwards to meet infiltrating groundwater at shallower depths, with partial to full isotopic exchange with carbonate rocks along its path, resulting in mixed magmatic-carbonate signature. Although the precise role and interaction of the involved subsurface processes remains debatable, this review study provides a baseline for future investigations.
Région wallonne : Direction générale des Technologies, de la Recherche et de l'Energie - DGTRE ; European Geosciences Union - EGU
ROSEAU - Doctorat en entreprise
Researchers ; Students
H2020 ; 731166 - GeoERA - Establishing the European Geological Surveys Research Area to deliver a Geological Service for Europe

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Barros et al. 2020 _ A review of the geology and origin of CO2 in mineral water springs in east Belgium.pdfPublisher postprint14.99 MBView/Open

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