Publications by authors named "J L Michelot"

Hydrochemical and isotopic characteristics of fluids from major geothermal fields of middle/low temperature in N/NE Greece are examined [basins: Strymon River (SR), Nestos River Delta (ND), Xanthi-Komotini (XK), Loutros-Feres-Soufli (LFS) and Rhodope Massif]. The geodynamic context is reflected to isotopic/chemical composition of fluids, heat flow values and elevated CO concentrations in emitted fluids. B and Li are derived from leaching of the geothermal systems hosting rocks.

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Speleothem-like deposits that develop underground in urban areas are an archive of the environmental impact of anthropic activities that has been little studied so far. In this paper, the sulfate content in shallow groundwater from northern Paris (France) is compared with the sulfur content in two 300-year-old urban carbonate deposits that grew in a historical underground aqueduct. The present-day waters of the aqueduct have very high sulfur and calcium contents, suggesting pollution from gypsum dissolution.

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A comparative study of selenium oxyanion sorption was carried out by means of batch sorption experiments on three argillaceous rocks that differ in their mineralogical compositions and textural properties. The results show no selenate (Se(VI)) sorption onto the argillaceous rocks after 60 days, but clear sorption of selenite (Se(IV)), the extent being closely related to the initial Se(IV) concentration. At the lowest concentration ([Se(IV)]eq < 10(-8) mol L(-1)), the ranking of rock affinity for Se(IV) is Black Shales > Opalinus Clay (OPA) > Upper Toarcian, with Rd values of 910 ± 70, 600 ± 65 and 470 ± 70 mL g(-1) respectively.

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Argillaceous formations are thought to be suitable natural barriers to the release of radionuclides from a radioactive waste repository. However, the safety assessment of a waste repository hosted by an argillaceous rock requires knowledge of several properties of the host rock such as the hydraulic conductivity, diffusion properties and the pore water composition. This paper presents an experimental design that allows the determination of these three types of parameters on the same cylindrical rock sample.

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A geochemical and isotopic (water and dissolved sulphate) study was performed on groundwater in the region of Marrakech, Morocco, with the aim of better understanding the regional hydrogeological system in order to improve water resources management. Significant differences in stable isotope contents and chemical compositions were observed between groundwater collected in the northern part of the region (Jbilets massif), where the basement schists outcrop, and that sampled in the southern part (Haouz basin), where the basement schists are overlaid by Plio-Quaternary deposits. The stable isotope composition of the groundwater showed that in the southern part the aquifer is mainly recharged from high-altitude precipitation over the High-Atlas Mountains, which may reach 600 mm per year or more, whereas, in the northern part, it is only recharged by lower-altitude local precipitation, which does not exceed 240 mm per year.

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