Thermal memory of sedimentary basins: case study from the Central European Basin System

This study deals with modelling the distribution of the subsurface temperature in space and the respective evolution in time in response to variations in the thermal boundary condition starting from the last glacial maximum (LGM, 26 ka BP). The aim here is to better understand (i) the feedback mechanisms between the atmosphere and solid earth components, and (ii) to which degree this coupling might be relevant for subsurface thermal modelling studies. The study area is the Central European Basin System (CEBS) in northern and Central Europe and state-of-the-art temperature reconstructions from the LGM to present have been used to model the surface thermal boundary conditions. Thereby, investigations on how such transient surface temperature conditions influence the temperature distribution with depth and over time within a heterogeneous sedimentary cover were carried out. The subsurface beneath the CEBS consists of more than 10 km thick sediments, which have been heavily restructured by salt movements during the whole Mesozoic evolution. Our 3D geological model resolves all major sedimentary and crustal domains, and we relied on the Max-Planck-Institute Earth System Model (MPI-ESM) temperature chronology. Starting from steady-state initial conditions, transient simulation runs are performed which cover the time from the LGM to present. Results are discussed in terms of temperature evolution over time and space. The focus will lie on quantifying subsurface conditions favourable to the establishment and maintenance of abnormally low temperature evolution and the related equilibration time within the sedimentary pile and which implications this might have for geothermal projects.