DISTRIBUTION OF DEEP CARBON-DIOXIDE IN RELATION TO THE STRUCTURE AND TECTONIC EVOLUTION OF SOUTH-EAST FRANCE

Throughout SE France, C-13-values of CO2 releases suggest that a varia ble part of the CO2 emission derives from mantle and/or lower crust. C arbon dioxide emission takes place in various geological settings. Geo dynamical analyses lead to the identification of five provinces: the S ub-Alpine Ranges, the French Massif Central, the Mediterranean part of the Languedoc, the western Pyrenees and the Alps at the West of the P enninic front. Possible correlations are suggested between CO2 flux an d tectonic history of the structural provinces. Possible processes by which CO2 is extracted from the mantle, stored and transferred to the surface are investigated for each of these provinces. Major crustal sc ale gas movements may have taken place during the Carboniferous (Varis can and Late Variscan tectogenesis), the Lias and Dogger (rifting), th e Upper Cretaceous and the Cenozoic (Alpine tectogenesis), A model of successive circulations of fluids on the scale of the whole Southeaste rn France CO2-belt is proposed. This integrated isotopic and geodynami c approach contributes to a better understanding of the regional CO2 f lux.