[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.
H2020 - 731166 - GeoERA - Establishing the European Geological Surveys Research Area to deliver a Geological Service for Europe
Name of the research project :
ROSEAU - Doctorat en entreprise
Funders :
DGTRE - Région wallonne. Direction générale des Technologies, de la Recherche et de l'Énergie EGU - European Geosciences Union EC - European Commission
Aeschbach-Hertig, W., Kipfer, R., Hofer, M., Imboden, D.M., Wieler, R., Signer, P., 1996. Quantification of gas fluxes from the subcontinental mantle: the example of Laacher See, a maar lake in Germany. Geochimica et Cosmochimica Acta, 60, 31–41. https://doi.org/10.1016/0016-7037(95)00370-3
Asselberghs, E., 1946. L'Eodévonien de l'Ardenne et des régions voisines. Mémoire de l'Institut géologique de l'Université de Louvain, 14, 1–598.
Babuska, V. & Plomerova, J., 1992. The lithosphere in central Europe-seismological and petrological aspects. Tectonophysics, 207, 141– 164. https://doi.org/10.1016/0040-1951(92)90475-L
Belanger, I., Delaby, S., Delcambre, B., Ghysel, P., Hennebert, M., Laloux, M., Marion, J.-M., Mottequin, B. & Pingot, J.-L., 2012. Redéfinition des unités structurales du front varisque utilisées dans le cadre de la nouvelle Carte géologique de Wallonie (Belgique). Geologica Belgica, 15, 169–175.
Bickle, M. & Kampman, N., 2013. Lessons in carbon storage from geological analogues. Geology, 41, 525–526. https://doi.org/10.1130/focus0420132.1
Bräuer, K., Kämpf, H., Niedermann, S., Strauch, G. & Weise, S.M., 2004. Evidence for a nitrogen flux directly derived from the European subcontinental mantle in the western Eger Rift, central Europe. Geochimica et Cosmochimica Acta, 68, 4935–4947. https://doi.org/10.1016/j.gca.2004.05.032
Bräuer, K., Kämpf, H., Niedermann, S. & Strauch, G., 2013. Indications for the existence of different magmatic reservoirs beneath the Eifel area (Germany): a multi-isotope (C, N, He, Ne, Ar) approach. Chemical Geology, 356, 193–208. https://doi.org/10.1016/j.chemgeo.2013.08.013
Bräuer, K., Kämpf, H., Niedermann, S. & Wetzel, H.-U., 2017. Regional distribution pattern of carbon and helium isotopes from different volcanic fields in the French Massif Central: Evidence for active mantle degassing and water transport. Chemical Geology, 469, 4–18. https://doi.org/10.1016/j.chemgeo.2017.04.004
Bultynck, P. & Dejonghe, L., 2001. Devonian lithostratigraphic units (Belgium). Geologica Belgica, 4, 39–69. https://doi.org/10.20341/gb.2014.043
Bultynck, P., Coen-Aubert, M. & Godefroid, J., 2000. Summary of the state of correlation in the Devonian of the Ardennes (Belgium-NE France) resulting from the decisions of the SDS. Courier Forschungsinstitut Senckenberg, 225, 91–114.
Burnside, N.M., Shipton, Z.K., Dockrill, B. & Ellam, R.M, 2013. Man-made versus natural CO2 leakage: a 400 k.y. history of an analogue for engineered geological storage of CO2 . Geology, 41, 471–474. https://doi.org/10.1130/G33738.1
Cartigny, P., Harris, J.W., Phillips, D., Girard, M. & Javoy, M., 1998. Subduction-related diamonds?-The evidence for a mantle-derived origin from coupled δ13 C–δ15 N determinations. Chemical Geology, 147, 147–159. https://doi.org/10.1016/S0009-2541(97)00178-2
Cartwright, I., Weaver, T., Tweed, S., Ahearne, D., Cooper, M., Czapnik, K. & Tranter, J., 2002. Stable isotope geochemistry of cold CO2-bearing mineral spring waters, Daylesford, Victoria, Australia: sources of gas and water and links with waning volcanism. Chemical Geology, 185, 71–91. https://doi.org/10.1016/S0009-2541(01)00397-7
Clark, I.D. & Fritz, P., 1997. Environmental Isotopes in Hydrogeology. Lewis Publishers, New York, 328 p.
Corin, F., 1965. Atlas des roches éruptives de Belgique. Mémoires du Service Géologique de Belgique, 4, 190 p.
Dassargues, A., 2018. Hydrogeology: groundwater science and engineering. Taylor & Francis CRC press, Boca Raton, 472 p. https://doi.org/10.1201/9780429470660
de Béthune, P., 1954. Carte géologique de Belgique (échelle 1/500.000). Atlas de Belgique, planche 8. Académie royale de Belgique, Bruxelles.
Debbaut, V., Cajot, O., Ruthy, I., Dassargues, A., Hanson, A. & M. Bouezmarni, 2014. Aquifères de l'Ardenne. In Dassargues, A. & Walraevens, K. (eds), Watervoerende lagen & grondwater in Belgïe – Aquifères & eaux souterraines en Belgique. Academia Press, Gent, 299–314.
Declercq, P.Y. & Dejonghe, L., 2010. OneGeology-Europe, 1:250,000. Internal database of the Geological Survey of Belgium.
Defosse, C. & Wery, A., 1975. Recherche sur les pouhons des Ardennes Liégeoises. Centre belge d’Etude et de Documentation des Eaux, 375, 1–7.
Deines, P., 1970. The carbon and oxygen isotopic composition of carbonates from the Oka carbonatite complex, Quebec, Canada. Geochimica et Cosmochimica Acta, 34, 1199–1225. https://doi.org/10.1016/0016-7037(70)90058-X
Fielitz, W., 1992. Variscan transpressive inversion in the northwestern central Rhenohercynian belt of western Germany. Journal of Structural Geology, 14, 547–563. https://doi.org/10.1016/0191-8141(92)90156-Q
Fielitz, W. & Mansy, J.L., 1999. Pre-and synorogenic burial metamorphism in the Ardenne and neighbouring areas (Rhenohercynian zone, central European Variscides). Tectonophysics, 309, 227–256. https://doi.org/10.1016/S0040-1951 (99)00141-9
Fourmarier, P., 1931. Les plissements calédoniens et les plissements hercyniens en Belgique. Annales de la Société géologique de Belgique, 54, B364–B384.
Geukens, F., 1957. Les failles bordières du Graben de Malmedy. Bulletin de la Société belge de Géologie, de Paléontologie et d’Hydrologie, 66, 71–81.
Geukens, F., 1989. Observations structurales entre La Reid et Surister (Massif de Theux). Annales de la Société géologique de Belgique, 112, 191–196.
Geukens F., 1995. “Strike slip deformation” des deux côtés du graben de Malmédy. Annales de la Société géologique de Belgique, 118, 139–146.
Geukens, F., 1999. Notes accompagnant une révision de la carte structurale du Massif de Stavelot. Aardkundige Mededelingen, 9, 183–190.
Geukens, F., 2007. Les sources de Spa et la Fenêtre de Theux. Geologica Belgica, 10, 127–130.
Geukens, F., 2008. Carte géologique de Wallonie: Notice explicative de la carte géologique Bra – Lierneux 55/3-4. Service Public de Wallonie, Direction générale opérationnelle Agriculture, Ressources naturelles et Environnement, Namur, 38 p.
Goemaere, E., Demarque, S., Dreesen, R. & Declercq, P.-Y., 2016. The geological and cultural heritage of the Caledonian Stavelot-Venn Massif, Belgium. Geoheritage, 8, 211–233. https://doi.org/10.1007/s12371-015-0155-y
Goes, S., Spakman, W. & Bijwaard, H., 1999. A lower mantle source for Central European volcanism. Science, 286, 1928–1931. https://doi.org/10.1126/science.286.5446.1928
Granet, M., Wilson, M. & Achauer, U., 1995. Imaging a mantle plume beneath the French Massif Central. Earth and Planetary Science Letters, 136, 281–296. https://doi.org/10.1016/0012-821X(95) 00174-B
Graulich, J.-M., 1969. Eaux minérales et thermales de Belgique. In Kačura, G. (ed.), XXIII International Geological Congress, Proceedings of Symposium II: Mineral and Thermal Waters of the World, A-Europe. Academia, Prague, Vol. 18, 9–15.
Griesshaber, E., O’Nions, R.K. & Oxburgh, E.R., 1992. Helium and carbon isotope systematics in crustal fluids from the Eifel, the Rhine Graben and Black Forest, F.R.G. Chemical Geology, 99, 213–235. https://doi.org/10.1016/0009-2541(92)90178-8
Hance, L., Dejonghe, L., Ghysel, P., Laloux, M. & Mansy, J.-L., 1999. Influence of heterogeneous lithostructural layering on orogenic deformation in the Variscan Front Zone (eastern Belgium). Tectonophysics, 309, 161–177. https://doi.org/10.1016/S0040-1951 (99)00137-7
Harris, C., Stock, W.D. & Lanham, J. 1997. Stable isotope constraints on the origin of CO2 gas exhalations at Bongwan, Natal. South African Journal of Geology, 100, 261–266.
Hensch, M., Dahm, T., Ritter, J., Heimann, S., Schmidt, B., Stange, S. & Lehmann, K., 2019. Deep low-frequency earthquakes reveal ongoing magmatic recharge beneath Laacher See Volcano (Eifel, Germany). Geophysical Journal International, 216, 2025–2036. https://doi.org/10.1093/gji/ggy532
Herbosch, A., Liégeois, J.P., Gärtner, A., Hofmann, M. & Linnemann, U., 2020. The Stavelot-Venn Massif (Ardenne, Belgium), a rift shoulder basin ripped off the West African craton: Cartography, stratigraphy, sedimentology, new U-Pb on zircon ages, geochemistry and Nd isotopes evidence. Earth-Science Reviews, 203, 103142. https://doi.org/10.1016/j.earscirev.2020.103142 Hoefs, J., 2009. Stable Isotope Geochemistry, 6th ed. Springer, Heidelberg, 285 p. https://doi.org/10.1007/978-3-540-70708-0
Hollmann, G. & Walter, R., 1995. The Variscan deformation front between Stavelot-Venn Anticline and Brabant Massif – a balanced geological cross section along the Liège-Theux traverse. Neues Jahrbuch für Geologie und Paläontologie Monatshefte, 1995/2, 92– 104. https://doi.org/10.1127/njgpm/1995/1995/92
IAEA/WMO, 2019. Global Network of Isotopes in Precipitation. The GNIP Database. https://www.iaea.org/services/networks/gnip, accessed 03/12/2019.
IPCC, 2005. Carbon Dioxide Capture and Storage. Cambridge University Press, Cambridge, 442 p.
IPCC, 2014. Climate Change 2014, Mitigation of climate change – Summary for policymakers and technical summary. In Edenhofer, O., Pichs-Madruga, R., Sokona, Y., Farahani, E., Kadner, S., Seyboth, K., Adler, A., Baum, I., Brunner, S., Eickemeier, P., Kriemann, B., Savolainen, J., Schlömer, S., von Stechow, C., Zwickel, T. & Minx, J.C. (eds), Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge, 1–107.
Karol, P.J., 2019. The Legacy of Carbon Dioxide: Past and Present Impacts. CRC Press, Boca Raton, 253 p. https://doi.org/10.1201/9780429200649
Karolytė, R., Johnson, G., Serno, S. & Gilfillan, S.M.V., 2017. The influence of water-rock reactions and O isotope exchange with CO2 on water stable isotope composition of CO2 springs in SE Australia. Energy Procedia, 114, 3832–3839. https://doi.org/10.1016/j.egypro.2017.03.1515
Kreemer, C., Blewitt, G. & Davis, P.M., 2020. Geodetic evidence for a buoyant mantle plume beneath the Eifel volcanic area, NW Europe. Geophysical Journal International, 222, 1316–1332. https://doi.org/10.1093/gji/ggaa227
Lamberty, P., Geukens, F., Marion, J.-M. & Mottequin, B., 2016. [Carte géologique de Wallonie:] Notice explicative de la carte géologique Harzé – La Gleize 49/7-8. ULG/Géologie/Eddy Lab & IRSNB, Liège, 86 p.
Lamberty, P., Geukens, F. & Marion, J.-M., 2017. [Carte géologique de Wallonie:] Notice explicative de la carte géologique Stavelot – Malmédy 50/5-6. ULG/Géologie/Eddy Lab, Liège, 86 p.
Langguth, H.R. & Plum, H., 1984. Untersuchung der Mineral-und Thermalquellen der Eifel auf geothermische Indikationen. Technologische Forschung und Entwicklung-Nichtnukleare Energietechnik, Lehr-und Forschungsgebiet für Hydrogeologie der RWTH Aachen, Bundesministerium für Forschung und Technologie, Bonn, Forschungsbericht, BMFT-FBT 84-019, 196 p.
Laurent, E., 1987. Contributions à l’étude de la genèse et de la protection des eaux minérales du Massif de Stavelot. Unpublished Ph.D. Thesis, Université Libre de Bruxelles, Faculté des Sciences Appliquées, Bruxelles, 365 p.
Le Gall, B., 1992. The deep structure of the Ardennes Variscan thrust belt from structural and ECORS seismic data. Journal of Structural Geology, 14, 531–546. https://doi.org/10.1016/0191-8141(92)90155-P
Liégeois, P.G., 1929. Les sources minérales gazeuses et ferrugineuses de l’Ardenne belge. Annales de l’Institut d’Hydrologie et de Climatologie, 6, 34 p.
Liégeois, P.G., 1931. L’anhydride carbonique naturel, les failles et les sondages. Bulletin de la Société belge de Géologie, de Paléontologie et d’Hydrologie, 41, 36–41.
May, F., 2002. Säuerlinge der Vulkaneifel und der Südeifel. Mainzer geowissenschaftliche Mitteilungen, 31, 7–57.
May, F., 2005. Alteration of wall rocks by CO2-rich water ascending in fault zones: natural analogues for reactions induced by CO2 migrating along faults in siliciclastic reservoir and cap rocks. Oil & Gas Science and Technology, 60, 19–32. https://doi.org/10.2516/ogst:2005003
May, F., Hoernes, S. & Neugebauer, H.J., 1996. Genesis and distribution of mineral waters as a consequence of recent lithospheric dynamics: the Rhenish Massif, Central Europe. Geologische Rundschau, 85, 782–799. https://doi.org/10.1007/s005310050112
McClay, K.R., 1991. Glossary of thrust tectonics terms. In McClay, K.R. (ed.), Thrust Tectonics. Chapman & Hall, London, 419–433.
Meier, T., Soomro, R.A., Viereck, L., Lebedev, S., Behrmann, J.H., Weidle, C., Cristiano, L. & Hanemann, R., 2016. Mesozoic and Cenozoic evolution of the Central European lithosphere. Tectonophysics, 692, 58–73. https://doi.org/10.1016/j.tecto.2016.09.016
Meschede, M., 2018. Deutschland im späten Paläozoikum. In Geologie Deutschlands. 2nd ed. Springer Spektrum, Berlin, 61–101. https://doi.org/10.1007/978-3-662-45298-1_10
Michot, P., 1980. Le segment tectogénique calédonien belge. Mémoires de l’Académie Royale de Belgique, classe des Sciences, Collection in 8°, 2ème série, 43, 61 p.
Monjoie, A., 1992. Les eaux souterraines de la région de Spa. Unpublished internal Spadel report, Laboratoire de Géologie de l’Ingénieur, d’Hydrogéologie et de Prospection Géophysique, Université de Liège.
Monjoie, A., 1995. Les eaux carbo-gazeuses et minéralisées du sud-est de la Belgique. La Houille Blanche 2/3, 100–105. https://doi.org/10.1051/lhb/1995022
Monjoie, A., 1997. Etude des eaux carbogazeuses du sud-est de la Belgique. Grant Spadel internal report 971, 51 p.
Papier, S., Baele, J.-M., Debouge, W., De Jong, J., Mattielli, N. & Gillan, D., 2016. Iron isotope fractionation in a Modern iron-oxidizing bacterial mat. In Proceedings of the 5th International Geologica Belgica Congress. University of Mons, Mons, p. 162. https://doi.org/10.20341/gbcp.vol2
Piper, A.M., 1944. A graphic procedure in the geochemical interpretation of water-analyses. Eos, Transactions American Geophysical Union, 25, 914–928. https://doi.org/10.1029/TR025i006p00914
Pirson, S., Spagna, P., Baele, J.-M., Damblon, F., Gerrienne, P., Vanbrabant, Y. & Yans, J., 2008. An overview of the geology of Belgium. Memoirs of the Geological Survey of Belgium, 55, 5–25.
Plum, H., 1989. Genetische Klassifikation und geochemische Interpretation der Mineral-und Thermalwässer der Eifel und Ardennen. Mitteilungen zur Ingenieurgeologie und Hydrogeologie, 34, 1–170.
Ritter, J.R.R., Jordan, M., Christensen, U.R. & Achauer, U., 2001. A mantle plume below the Eifel volcanic fields, Germany. Earth and Planetary Science Letters, 186, 7–14. https://doi.org/10.1016/S0012-821X(01)00226-6
Rozanski, K., Araguás-Araguás, L. & Gonfiantini, R., 1993. Isotopic patterns in modern global precipitation. In Swart, P.K., Lohmann, K.C., McKenzie, J. & Savin, S. (eds), Climate Change in Continental Isotopic Records. American Geophysical Union, Washington, Geophysical Monograph, 78, 1–37.
Schmincke, H.U., 2007. The Quaternary volcanic fields of the East and West Eifel (Germany). In Ritter, J.R.R. & Christensen, U.R. (eds), Mantle Plumes. Springer, Berlin, 241–322. https://doi.org/10.1007/978-3-540-68046-8_8
Schreyer, W., Bernhardt, H.-J. & Medenbach, O., 1992. Petrologic evidence for a rhodochrosite precursor of spessartine in coticules of the Venn-Stavelot Massif, Belgium. Mineralogical Magazine, 56, 527–532. https://doi.org/10.1180/minmag.1992.056.385.08
Schroyen, K. & Muchez, P., 2000. Evolution of metamorphic fluids at the Variscan fold-and-thrust belt in eastern Belgium. Sedimentary Geology, 131, 163–180. https://doi.org/10.1016/S0037-0738(99)00133-5
Schumacher, M.E., 2002. Upper Rhine Graben: the role of pre-existing structures during rift evolution. Tectonics, 21, 6–17. https://doi.org/10.1029/2001TC900022
Smets, S. & Wollast, R., 1988. Contribution à l'étude de la genèse des eaux carbogazeuses de Stoumont. Unpublished Master Thesis, Université libre de Bruxelles, Bruxelles, 68 p.
Theye, T., Schreyer, W. & Fransolet, A.-M., 1996. Low-temperature, low-pressure metamorphism of Mn-rich rocks in the Lienne Syncline, Venn-Stavelot Massif (Belgian Ardennes), and the role of carpholite. Journal of Petrology, 37, 767–783. https://doi.org/10.1093/petrology/37.4.767
Van Beneden, G., 1947. Recherche sur l’origine et la genèse des eaux minérales de Spa et des Ardennes. Journal de Pharmacie de Belgique, 2, 1–28.
Vanbrabant, Y, 2001. Evolution géodynamique de la partie orientale de l’allochtone de l’Ardenne. Observations structurales et modélisations numériques. Unpublished Ph.D. Thesis, Université de Liège, Faculté des Sciences, Liège, 350 p.
Vanbrabant, Y. Jongmans, D., Hassani, R. & Bellino, D., 1999. An application of two-dimensional finite-element modelling for studying the deformation of the Variscan fold-and-thrust belt (Belgium). Tectonophysics, 309, 141–159. https://doi.org/10.1016/S0040-1951(99)00136-5
Vanbrabant, Y., Braun, J. & Jongmans, D., 2002. Models of passive margin inversion: Implications for the Rhenohercynian fold-and-thrust belt, Belgium and Germany. Earth and Planetary Science Letters, 202, 15–29. https://doi.org/10.1016/S0012-821X(02)00751-3
Van den Broeck, E. 1888. Les eaux minérales de Spa: observations préliminaires sur la thèse d’une origine non interne. Bulletin de la Société belge de Géologie, de Paléontologie et d’Hydrologie, 2, 235–260.
Veizer, J., 2009. Carbon isotope variations over geologic time. In Gornitz, V. (ed.), Encyclopedia of Paleoclimatology and Ancient Environments. Springer, Dordrecht, Encyclopedia of Earth Sciences Series, 128–133. https://doi.org/10.1007/978-1-4020-4411-3_31
Verniers, J., Herbosch, A., Vanguestaine, M., Geukens, F., Delcambre, B., Pingot, J.-L., Belanger, I., Hennebert, M., Debacker, T., Sintubin, M. & De Vos, W., 2001. Cambrian-Ordovician-Silurian lithostratigraphic units (Belgium). Geologica Belgica, 4, 5–38. https://doi.org/10.20341/gb.2014.042
von Winterfeld, C.H., 1994. Variszische Deckentektonik und devonische Beckengeometrie der Nordeifel – Ein quantitatives Model. Profilbilanzierung und Strain-Analyse im Linksrheinischen Schiefergebirge). Aachener Geowissenschaftliche Beiträge, 2, 320 p.
White, W.M., 2015. Isotope Geochemistry. John Wiley & Sons, Chichester, 496 p.
Wollast R., 1985. Etude du périmètre de protection de la zone de Stoumont et environs, Rapport final. Ministère de la Région Wallonne pour l'eau, l'environnement et la vie rurale, Namur, 156 p.
Wollast, R. & Wollast, A., 1987. Etude géochimique des eaux carbo-gazeuses de la région de Stoumont. In Colloque sur « Les eaux souterraines en Wallonie », Ministère de la Région Wallonne, Bilan et Perspectives Eso'87, 152–167.