Integration of geological, hydrochemical and geophysical methods for prospecting thermal water resources: The case of the Hmeïma region (Central–Western Tunisia)

Inoubli, N.; Gouasmia, Mouez; Gasmi, Mohamed; Mhamdi, Abdelkader; Dhia, Hamed Ben

doi:10.1016/j.jafrearsci.2006.04.009

Cited by 20 publications

(7 citation statements)

References 4 publications

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“…10d. This confirms that Na and Cl concentrations are primarily controlled by dissolution of the saliferous Triassic formations rich in halite (Iundt, 1971;Kamel et al, 2005;Guendouz and Michelot, 2006;Inoubli et al, 2006;Trabelsi et al, 2009), which buffers the Na/Cl ratio of most samples at~1. This process is active over the three Tunisian domains.…”

Section: Geochemical Processes : Sources Of Salts and Link With Geologysupporting

confidence: 59%

Regional variations in the chemical and helium–carbon isotope composition of geothermal fluids across Tunisia

et al. 2011

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Tunisia has numerous thermo-mineral springs. Previous studies have shown that their chemical composition and occurrence are strongly influenced by the regional geology. However little work has been done so far to study the isotopic composition of volatiles associated with these geothermal manifestations. Here, we report on the results of an extensive survey of both natural hot springs and production wells across Tunisia, aimed at investigating the spatial distribution of thermal fluids' geochemical characteristics and He-C isotopic composition. The chemistry of the analyzed samples highlights the heterogeneity of the water mineralization processes in Tunisia, as a consequence of the complex geological and tectonic setting of the country. In terms of chemical composition, we are able to conclude, however, that dissolution of halite and gypsum plays a key control on groundwater chemistry. Helium and carbon isotope systematics confirm the prevalently crustal origin of the volatiles interacting with the aquifer systems, consistent with the absence of any recent magmatism. Most samples are characterized by crustal-type helium ( He ratio reaches 2.4 Ra (corresponding to 30% of mantle-derived helium) at the Ain Garci site, a CO 2 rich mineral spring located some 30 km south of the city of Zaghouan. This mantle signature is consistent with the fact that the Pelagian Block, to which Eastern Tunisia belongs, has been deeply affected by extensional and transtensional tectonics since the opening of the Tethys, a process which is still ongoing in the Sicily channel (Pantelleria Rift). As a whole however, our results show that the Italian mantle gas anomaly only marginally extends to Northwestern Africa.

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Section: Geochemical Processes : Sources Of Salts and Link With Geologysupporting

confidence: 59%

Regional variations in the chemical and helium–carbon isotope composition of geothermal fluids across Tunisia

et al. 2011

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“…Many caves and related phenomena can be observed in the "Buda Karst" (Dublyansky 1995;Erőss et al 2008b). Europe's second-largest occurrence of mineral and thermal springs, in Stuttgart, Germany, is also associated with a karst aquifer (Ufrecht 2006a), as are many other thermal springs and spas in Germany (Käss and Käss 2008), Switzerland (Muralt et al 1997), France (Levet et al 2002), Italy (Minissale et al 2002), the UK (Brassington 2007;Gallois 2007), Turkey (Gemici and Filiz 2001), Jordan (Bajjali et al 1997), Tunisia (Inoubli et al 2006), Algeria (Djidi et al 2008), Canada (Allen et al 2006;Van Everdingen 1991), China (Ma et al 2009;Zhou et al 2008) and many other regions of the world.…”

Section: Introductionmentioning

confidence: 99%

Review: Thermal water resources in carbonate rock aquifers

et al. 2010

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The current knowledge on thermal water resources in carbonate rock aquifers is presented in this review, which also discusses geochemical processes that create reservoir porosity and different types of utilisations of these resources such as thermal baths, geothermal energy and carbon dioxide (CO 2 ) sequestration. Carbonate aquifers probably constitute the most important thermal water resources outside of volcanic areas. Several processes contribute to the creation of porosity, summarised under the term hypogenic (or hypogene) speleogenesis, including retrograde calcite solubility, mixing corrosion induced by cross-formational flow, and dissolution by geogenic acids from deep sources. Thermal and mineral waters from karst aquifers supply spas all over the world such as the famous bath in Budapest, Hungary. Geothermal installations use these resources for electricity production, district heating or other purposes, with low CO 2 emissions and land consumption, e.g. Germany's largest geothermal power plant at Unterhaching near Munich. Regional fault and fracture zones are often the most productive zones, but are sometimes difficult to locate, resulting in a relatively high exploration uncertainty. Geothermal installations in deep carbonate rocks could also be used for CO 2 sequestration (carbonate dissolution would partly neutralise this gas and increase reservoir porosity). The use of geothermal installations to this end should be further investigated.

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“…During the progressive uplift and the deformation of Triassic rocks, a new diagenetic setting, with a major shift in pore fluid chemistry, prevails in the pore space so that the lowered alkalinity could readily yield the maturity of quartz crystals especially when the pore fluids became progressively oxygenated. The role of halokinetic movements, by the intrusion along preexisting faults in the hydrogeological basins in central Tunisia is implied by Chaibi et al (2013), Tanfous et al (2005) and Inoubli et al (2006). In this complex mechanism, the main acting factors of silica diagenesis are summarised in (i) the immediate availability of abundant silica-rich and oxygenated flushing meteoric waters from aquifer-bearing formations, (ii) the steady pace of halokinetic uplift of salt diapir and (iii) the subsequent increase of the overall temperature of surrounding sedimentary rocks and overburdens.…”

Section: Growth Model For the Quartzmentioning

confidence: 99%

Large euhedral quartz crystals in the Triassic dolomites and evaporites of central Tunisia: implications for silica diagenesis in sulphate-rich and high-Mg environments

Henchiri

Abidi²,

Jemmali

2015

Arab J Geosci

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The Triassic salt diapirs in central Tunisia show splendid large multicoloured crystals of quartz. The study of these crystals and their host rocks sheds light on their origin and, more specifically, the relationships between silica authigenesis and its host rocks. Petrographic analyses of quartz crystals show strongly undulose euhedral to subeuhedral crystals (generally rhombohedral crystals) with concentration of many solid inclusions including sulphates and dolomite. Voids, shelter pores and negative crystals of gypsum, anhydrite and dolomite rhombs are found near the central parts of the crystals. Preserved anhydrite inclusions and dissolved evaporite are also found in these crystals. XRD analyses of white and black quartz crystals show crystalline alpha-quartz as the only silica phase present in most samples with a crystallinity index of 5. Accessory minerals include small relict patches of unreplaced calcite, gypsum, dolomite and anhydrite that escaped replacement. Fourier transform infrared (FTIR) spectra reveal the presence of abundant sulphate and organic compound included in the silica masses. The quartz crystals occurring in the allochthonous Triassic salt bodies are typically authigenic owing to the euhedral shape, the absence of any siliciclastic grains in the host rocks of quartz crystals, and also, to the absence of any sedimentary, wind or water-induced controls on the crystal distribution in their hosting rocks. Quartz growth in Triassic salt diapirs is a complex multistage and possibly continuous mechanism. During the progressive uplift of Triassic evaporites and dolomites, the dissolution of evaporites is enhanced and creates pores for the precipitation of the silica with development of larger quartz crystals. The colour variability in the quartz is ascribed to different ambient materials or fluids during crystallization. Remnant organic matter, before being altered and oxidised, could likely be included in the silica masses of the quartz and may serve not only to catalyse the precipitation and the growth but also to darken the quartz as well. Silica necessary for the formation of the quartz is mainly derived from two potential sources: (1) the presence of green and red clays in the Triassic salts and (2) silica-rich diagenetic fluids percolating from adjacent Lower Cretaceous sandy aquifers.

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Integration of geological, hydrochemical and geophysical methods for prospecting thermal water resources: The case of the Hmeïma region (Central–Western Tunisia)

Cited by 20 publications

References 4 publications

Regional variations in the chemical and helium–carbon isotope composition of geothermal fluids across Tunisia

Regional variations in the chemical and helium–carbon isotope composition of geothermal fluids across Tunisia

Review: Thermal water resources in carbonate rock aquifers

Large euhedral quartz crystals in the Triassic dolomites and evaporites of central Tunisia: implications for silica diagenesis in sulphate-rich and high-Mg environments

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