@article{KaiserCacaceScheckWenderothetal.2011, author = {Kaiser, Bjoern Onno and Cacace, Mauro and Scheck-Wenderoth, Magdalena and Lewerenz, Bjoern}, title = {Characterization of main heat transport processes in the Northeast German Basin constraints from 3-D numerical models}, series = {Geochemistry, geophysics, geosystems}, volume = {12}, journal = {Geochemistry, geophysics, geosystems}, number = {13}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1029/2011GC003535}, pages = {17}, year = {2011}, abstract = {To investigate and quantify main physical heat driving processes affecting the present-day subsurface thermal field, we study a complex geological setting, the Northeast German Basin (NEGB). The internal geological structure of the NEGB is characterized by the presence of a relatively thick layer of Permian Zechstein salt (up to 5000 m), which forms many salt diapirs and pillows locally reaching nearly the surface. By means of three-dimensional numerical simulations we explore the role of heat conduction, pressure, and density driven groundwater flow as well as fluid viscosity related effects. Our results suggest that the regional temperature distribution within the basin results from interactions between regional pressure forces as driven by topographic gradients and thermal diffusion locally enhanced by thermal conductivity contrasts between the different sedimentary rocks with the highly conductive salt playing a prominent role. In contrast, buoyancy forces triggered by temperature-dependent fluid density variations are demonstrated to affect only locally the internal thermal configuration. Locations, geometry, and wavelengths of convective thermal anomalies are mainly controlled by the permeability field and thickness values of the respective geological layers.}, language = {en} } @article{NoackScheckWenderothCacace2012, author = {Noack, Vera and Scheck-Wenderoth, Magdalena and Cacace, Mauro}, title = {Sensitivity of 3D thermal models to the choice of boundary conditions and thermal properties: a case study for the area of Brandenburg (NE German Basin)}, series = {Environmental earth sciences}, volume = {67}, journal = {Environmental earth sciences}, number = {6}, publisher = {Springer}, address = {New York}, issn = {1866-6280}, doi = {10.1007/s12665-012-1614-2}, pages = {1695 -- 1711}, year = {2012}, abstract = {Based on newly available data of both, the structural setting and thermal properties, we compare 3D thermal models for the area of Brandenburg, located in the Northeast German Basin, to assess the sensitivity of our model results. The structural complexity of the basin fill is given by the configuration of the Zechstein salt with salt diapirs and salt pillows. This special configuration is very relevant for the thermal calculations because salt has a distinctly higher thermal conductivity than other sediments. We calculate the temperature using a FEMethod to solve the steady state heat conduction equation in 3D. Based on this approach, we evaluate the sensitivity of the steady-state conductive thermal field with respect to different lithospheric configurations and to the assigned thermal properties. We compare three different thermal models: (a) a crustal-scale model including a homogeneous crust, (b) a new lithosphere-scale model including a differentiated crust and (c) a crustal-scale model with a stepwise variation of measured thermal properties. The comparison with measured temperatures from different structural locations of the basin shows a good fit to the temperature predictions for the first two models, whereas the third model is distinctly colder. This indicates that effective thermal conductivities may be different from values determined by measurements on rock samples. The results suggest that conduction is the main heat transport mechanism in the Brandenburg area.}, language = {en} } @article{KaiserCacaceScheckWenderoth2013, author = {Kaiser, Bj{\"o}rn Onno and Cacace, Mauro and Scheck-Wenderoth, Magdalena}, title = {Quaternary channels within the Northeast German Basin and their relevance on double diffusive convective transport processes - constraints from 3-D thermohaline numerical simulations}, series = {Geochemistry, geophysics, geosystems}, volume = {14}, journal = {Geochemistry, geophysics, geosystems}, number = {8}, publisher = {American Geophysical Union}, address = {Washington}, issn = {1525-2027}, doi = {10.1002/ggge.20192}, pages = {3156 -- 3175}, year = {2013}, abstract = {The internal geological structure of the Northeast German Basin (NEGB) is affected by intense salt diapirism and by the presence of several stratified aquifer complexes of regional relevance. The shallow Quaternary to late Tertiary freshwater aquifer is separated from the underlying Mesozoic saline aquifers by an embedded Tertiary clay enriched aquitard (Rupelian Aquitard). An important feature of this aquitard is that hydraulic connections between the upper and lower aquifers do exist in areas where the Rupelian Aquitard is missing (hydrogeological windows). Three-dimensional thermohaline numerical simulations are carried out to investigate the effects of such hydrogeological windows in the Rupelian Aquitard on the resulting groundwater, temperature, and salinity distributions. Numerical results suggest that hydrogeological windows act as preferential domains of hydraulic interconnectivity between the different aquifers at depth and enable vigorous heat and mass transport which causes a mixing of warm and saline groundwater with cold and less saline groundwater within both aquifers. In areas where the Rupelian Aquitard confines the Mesozoic aquifer, dissolved solutes from major salt structures are transported laterally giving rise to plumes of variable salinity content ranging from few hundreds of meters to several tens of kilometers. Furthermore, destabilizing thermal buoyancy forces may overwhelm counteracting stabilizing salinity induced forces offside of salt domes. This may result in buoyant upward groundwater flow transporting heat and mass to shallower levels within the same Mesozoic Aquifer.}, language = {en} } @article{KaiserCacaceScheckWenderoth2013, author = {Kaiser, Bj{\"o}rn Onno and Cacace, Mauro and Scheck-Wenderoth, Magdalena}, title = {3D coupled fluid and heat transport simulations of the Northeast German Basin and their sensitivity to the spatial discretization - different sensitivities for different mechanisms of heat transport}, series = {Environmental earth sciences}, volume = {70}, journal = {Environmental earth sciences}, number = {8}, publisher = {Springer}, address = {New York}, issn = {1866-6280}, doi = {10.1007/s12665-013-2249-7}, pages = {3643 -- 3659}, year = {2013}, abstract = {Based on a numerical model of the Northeast German Basin (NEGB), we investigate the sensitivity of the calculated thermal field as resulting from heat conduction, forced and free convection in response to consecutive horizontal and vertical mesh refinements. Our results suggest that computational findings are more sensitive to consecutive horizontal mesh refinements than to changes in the vertical resolution. In addition, the degree of mesh sensitivity depends strongly on the type of the process being investigated, whether heat conduction, forced convection or free thermal convection represents the active heat driver. In this regard, heat conduction exhibits to be relative robust to imposed changes in the spatial discretization. A systematic mesh sensitivity is observed in areas where forced convection promotes an effective role in shorten the background conductive thermal field. In contrast, free thermal convection is to be regarded as the most sensitive heat transport process as demonstrated by non-systematic changes in the temperature field with respect to imposed changes in the model resolution.}, language = {en} }