Influence of Quaternary glaciations on subsurface temperatures and pressures in NE onshore Netherlands

Several glacial ice advances shaped the present-day morphology of central Europe during the Quaternary. Two Pleistocene glaciations, the Elsterian and the Saalian stages, advanced as far as the north-eastern part of the onshore Netherlands. Remains of these glacial advances and retreats are deep erosional glacial valleys of the Elsterian glaciation and till sheets, glacio-tectonic ridges and glacial basins assigned to the Saalian complex. In this study, we present the effects of sequential loading and unloading of ice sheets on the temperature distribution and rock properties of the subsurface using 3D basin and petroleum systems modelling in the northeast Netherlands. A 3D basin and petroleum systems model was set up, incorporating the Neogene to Quaternary Upper North Sea Group down to the Carboniferous Limestone Group, was used and extended to incorporate sequential loading and unloading of ice sheets in the Pleistocene. Subsurface temperatures are decreased due to low ground and ice sheet base temperatures, with minimum temperatures observed at the beginning of a glacial stage. During an ice sheet coverage, the subsidence caused by loading leads to an increase in temperatures, therefore counteracting a low ice sheet base temperatures. Generally, a lower geothermal gradient is observed in the upper layers of the 3D model. Pore pressures build up during glacials caused by extra loading and then retreat to a pre-loading state with time, depending on the strength of ice loading, the depth of the layer, as well as the rock properties of the overburden. (Poster)