Pleistocene age paleo-groundwater inferred from water-stable isotope values in the central part of the Baltic Artesian Basin |
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| Authors: | Alise Babre Andis Kalvāns Konrāds Popovs Inga Retiķe Aija Dēliņa Rein Vaikmäe |
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| Institution: | 1. Centre of Geological Processes Research and Modelling, Department of Geology, University of Latvia, Riga, Latvia;2. Institute of Ecology and Earth Sciences, Department of Geology, University of Tartu, Tartu, Estonia;3. Institute of Geology, Tallinn University of Technology, Tallinn, Estonia |
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| Abstract: | A new data set of δ2H and δ18O in the groundwater from the central part of the Baltic Artesian Basin is presented. The hydrogeological section is subdivided into stagnation, slow exchange and active exchange zones. Na–Ca–Cl brine found at the deepest part – the stagnation zone – is characterized by δ18O values above ?5?‰ and δ2H values approaching ?40?‰ with respect to Vienna Standard Mean Ocean Water. The slow exchange zone where waters of mostly intermediate salinity reside is characterized by δ18O values around ?11.7?‰ and δ2H values around ?85.3?‰. Mean δ18O and δ2H values of the fresh groundwater in the active water exchange zone are ?11.1 and ?79.9?‰, respectively. Characteristically, the groundwater in the active and slow exchange zone is isotopically more depleted compared with the precipitation values observed, and the depletion increases with depth down to the level where strongly enriched brines are encountered. |
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| Keywords: | Baltic Artesian Basin brines d-excess groundwater development hydrogen-2 isotope hydrology Latvia oxygen-18 palaeohydrogeology |
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