Fluid flow, heat transport and solute migration in relation to young processes
Final Report Abstract
In the Schleswig-Holstein area, salty groundwaters are not always spatially related to the presence of shallow sat structures. Furthermore, hydrochemical data point to instable salinity profiles and to the occurrences of deep brines close to the surface. The salinity profiles highlighted the presence of brine lenses and inverted salinity profiles throughout the basin. Furthermore, deep formation brines observed at the surface of the Hemmelsdorf basin point toward strong interaction between deep fluid flow and shallower aquifer systems. Therefore, complex interaction between shallow and deep solute migration must occur. Numerical simulation of fluid flow, mass and heat transport have been carried out in order to understand the role of shallow salt dissolution and young geological features on groundwater flow as well as to investigate the interrelationships between shallow and deep aquifersystems. For these purposes, a shallow (-500 m) and a deep profile model (- 5 km) have been constructed in order to study: (1) the role of shallow salt dissolution and young geological units on groundwater flow, (2) the interrelationships between shallow brine migration and deep fluid flow and (3) the impact of the geothermal gradient on the whole groundwater system, (4) the impact of anthropogenic activities. These investigations provided possible explanations for these unsolved issues and allowed to gain insights on transport processes within geothermal basin. The results indicate that different flow regimes coexist within the study area. Shallow brine migration is strongly controlled by the geological features of the basin such as faults, glacial channels and sand layers. Furthermore, shallow salt dissolution is the major cause for gravitational convection in the deeper aquifers. This source of salinization from above leads to the formation of instable salinity profiles at 2 km depth. Further interactions between shallow and deep fluid flow exist in the eastern part of the basin where brine upconing is due to both topography-driven flow and thermohaline convection. The simulations also showed that the hydraulic conductivity of the stratigraphic units influences the brine regime on a regional-scale. Gravitational convection is likely to occur in permeable units located near shallow salt structures, while thermohaiine convection persists within thick permeable areas in which salt dissolution is not the dominant process. Beside topography-driven flow, the different convective regimes are a mechanism for extensive solute exchange between shallow and deep aquifers.
Publications
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2006. Deep fluid migration combining numerical modelling and hydrochemical data. Geophysical Research Abstracts, Vol. 8, Abstract No: EGU06-A-00856, 02-07/04/2006, Wien, Austria
Bayer, U., Magri, F., Pekdeger, A., Tesmer M.
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2006. Modelling of large-scale density driven flow by example of the North East German Basin. International FEFLOW User Conference. Conference Proceedings, 197-207
Magri, F., Bayer, U.
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Brine migration in the NE German Basin: results combining numerical modelling and hydrochemical data. Schriftenreihe der Deutschen Gesellschaft für Geowissenschaften Heft 50, 01-03/10/06, Berlin
Magri, F., Bayer, U., Pekdeger, A.
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Hydrochemical and numerical modelling of geogenic groundwater salinzation in the North German Basin. Geophysical Research Abstracts, Vol. 8, Abstract No: EGU06-A-00928, 02-07/04/2006, Wien, Austria
Tesmer, M., Magri F., Moller P., Pekdeger, A., Bayer, U.
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Mechanisms driving saline waters in the North East German Basin: results from thermohaline simulations. Geophysical Research Abstracts, Vol. 8, Abstract No: EGU06-A-01486. 02-07/04/2006, Wien, Austria
Magri, F., Bayer, U.
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Numerical Modelling of Thermohaline Convection in the North-East German Basin: Results of Finite Volume Simulations. Geophysical Research Abstracts, Vol. 8, Abstract No: EGU06-A-09538, 02-07/04/2006, Wien, Austria
Enchery, G., Fuhrmann, J., Magri, F., Bayer, U.
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Brine migration in relation to young processes: the Schleswig-Holstein example. Geophysical Research Abstracts, Vol. 9, Abstract No: EGU2007-A-01091, 15.- 21/04/2007,Wien, Austria
Magri, F., Bayer, U.
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Deep-fluid flow in the North East German basin: possible transport processes. 67. Jahrestagung der Deutschen Geophysikalischen Gesellschaft. Aachen, 26. bis 29. März 2007
Magri, F., Bayer, U.
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Numerical simulations of shallow and deep brine migration in the S-H Region, Germany. Rendiconti della Società Geologica Italiana. Drt 2007 16th Conference on Deformation mechanisms, Rehology and Tectonics, Volume V, Nuova Serie, p 143. 26/09/07 - 30/09/07, Milan, Italy
Magri, F., Bayer, U.
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2008. Salinization of groundwater in the North German Basin: results from conjoint investigation of major, trace element and multi-isotope distribution. Int J Earth Sci (Geol Rundsch) 97:1057- 1073
Möller, P., Weise S.M., Tesmer M., Dulski P., Pekdeger A., Bayer U., Magri F.
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2008. Salinization problems in the NEGB: results from thermohaline simulations. Int J Earth Sci (Geol Rundsch) 97:1075-1085
Magri, F., Bayer, U., Jahnke, C., Tesmer, M., Möller, P., Pekdeger, A., Voigt, H.J.
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2008. Salty groundwater flow in the shallow and deep aquifer systems of the Schleswig-Holstein area (North German Basin). Tectonophysics
Magri F., Bayer U., Pekdeger A., Otto R., Thomsen C., Maiwald U.
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2008. Temperature fields, petroleum maturation and fluid flow in the vicinity of salt domes. In: Littke, R, Bayer, U, Gajewski, D, and Nelskamp, S (eds.) Dynamics of Complex Sedimentary Basins. The Example of the Central European Basin System. Springer-Verlag, Berlin-Heidelberg-New York
Magri F., Littke R., Rodon S., Bayer U., Urai J.L.
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2008. Viscosity effects and anthropogenic impact on thermohaline flow in the Schleswig-Holstein region. DGMK/ÖGEW-Frühjahrstagung 2008, Fachbereich Aufsuchung und Gewinnung, Celle, 305-313
Magri, F., Bayer, U.
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Coupled groundwater transport processes in a shallow salt dome environment. The 33rd International Geological Congress, SES-05 Dynamics of complex intracontinental basins, 6-14/08/08 Oslo, Norway
Magri, F., Bayer, U.
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Deep fluid transport processes in sedimentary basins. 160th annual meeting of the Deutsche Gesellschaft für Geowissenschaften and 98th annual meeting of the Geologische Vereinigung e.V., Aachen, 29. September - 2. Oktober 2008
Magri, F., Bayer, U., Plotnikova I.
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Hydrogeochemische und geothermische Indikatoren zur Charakterisierung der Wechselwirkungen zwischen oberflächennahem und tiefem Grundwasser am Beispiel des Oldesloer Trogs. Tagung der FH-DGG in Göttingen. Göttingen, 21 bis 26 Mai 2008
Maiwald, U., Kohfahl, O., Otto, R., Tesmer M., Lorenz, G., Magri, F., Pekdeger, A.
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Impact of anthropogenic activities on brine and heat transport processes in the Schleswig-Holstein region (Germany). Geophysical Research Abstracts, Vol. 10., Abstract No: EGU2008-A-00149, 13.-19/04/2008, Wien, Austria
Magri, F., Bayer, U.
