Skip to content

Geothermal systems and carbon storage in Tunisia

Badiaa CHELLI

Abstract

In Tunisia, subsurface Cretaceous magmatism is regularly present as lava flows, intrusions and pyroclastic materials which were recorded at different Cretaceous lithostratigraphic intervals. The spatiotemporal distribution of magmatic events indicates their close association to major faults corridors which were reactivated by regional field constraints. For that, magmatism is found alongside deeply rooted faults where crustal melting was activated (Laridhi Ouazaa 1994; Matoussi Kort 2008). In this area, magmatic activity is understood to be associated to increasing heat flow and fluid migration (Matoussi Kort et al. 2008, 2009). In addition, several boreholes, drilled in the area, have frequently shown different gas occurrences associated to different Cretaceous intervals. For that, the present study will try to shed some light to the possible linkage between Cretaceous magmatism, hydrothermalism and such gas expressions in Eastern Tunisia. This paper, using subsurface data from seismic reflection (Geophysic, Bedir 1990), Geothermal data  and studying selected samples collected from drilled boreholes in Tunisia, discusses: (i) structural and petrological evidence for fluid infiltration during cooling of Cretaceous magmatism in Eastern Tunisia; (ii) the impact of both heat and chemical elements income (associated to the magmatic rocks genesis) on the neoformation of new mineral phases within the enclosing sedimentary beds; (iii) the different CO2, H2S, CH4 and N2 gas expressions in the area and tries to identify their origin using carbon stable isotope data.