Numerical 3D basin modeling is used to reconstruct the burial and temperature histories in onshore northeastern Netherlands, incorporating the four main geological structural elements Groningen Platform, Lauwerszee Trough, Friesland Platform, and Lower Saxony Basin. The structural framework is based on recently published open access depth surface data; public temperature and vitrinite reflectance data from 28 wells are used to evaluate burial and temperature histories. Four modeled burial histories and the maturity evolution of the structural elements are presented. The hydrocarbon generation in major source rock intervals in the Carboniferous, Jurassic, and Cretaceous is simulated using recently published kinetic and literature data. Modeling results indicate highest present-day temperatures and maturities of the Paleozoic sedimentary succession in the Lauwerszee Trough and the Lower Saxony Basin, where the deepest burial occurred. Two major phases of deep burial and subsequent uplift occurred in Carboniferous to Permian times and from the Triassic to the Jurassic. Both intervals strongly influenced the maturation and transformation of kerogen from Paleozoic source rocks. The highest modeled maturities of the Mesozoic groups are observed in depressions between salt diapirs in the Lower Saxony Basin. Out of the two major source rock intervals within the Mesozoic, the Cretaceous Wealden Shale generated hydrocarbons from Late Cretaceous times.

Pleistocene glacial stages were implemented into a 3D basin and petroleum systems model of the northeastern Netherlands to address the influence of low surface temperatures and the mechanical loading of ice sheets on the subsurface. Two ice sheet thickness scenarios were used based on published data. Overall, Quaternary glacial stages have a substantial impact on the temperature and pressure distribution in the subsurface. Subsurface temperatures are significantly reduced during glacial stages, leading to lowered present-day temperatures and a low geothermal gradient in the shallow subsurface. In deeply buried sedimentary formations, pressures build up with every glacial advance resulting in overpressures at the present day. Glacial stages do not directly influence the petroleum generation of petroleum source rocks in the area, but high pressures during loading might have impacted petroleum expulsion of the early mature Coevorden Formation. Hydrocarbon accumulations in the Lower Saxony Basin were simulated to investigate the possible effects of mechanical ice loading and unloading on hydrocarbon migration. A loss of Coevorden Formation-sourced hydrocarbons to the surface was calculated in the Lower Saxony Basin during the glacial stages, indicating an influence of glacial loading on the Mesozoic petroleum system.

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Abstract. Archimedes' principle states that the upward buoyant force exerted on a solid immersed in a fluid is equal to the weight of the fluid that the solid displaces. In this 3D salt-reconstruction study we treat Zechstein evaporites in the Netherlands as a pseudo-fluid with a density of 2.2 g cm−3, overlain by a lighter and solid overburden. Three-dimensional sequential removal (backstripping) of a differential sediment load above the Zechstein evaporites is used to incrementally restore the top Zechstein surface. Assumption of a constant subsurface evaporite volume enables the stepwise reconstruction of base Zechstein and the approximation of 3D salt-thickness change and lateral salt redistribution over time. The salt restoration presented is sensitive to any overburden thickness change caused by tectonics, basin tilt, erosion or sedimentary process. Sequential analysis of lateral subsurface salt loss and gain through time based on Zechstein isopach difference maps provides new basin-scale insights into 3D subsurface salt flow and redistribution, supra-salt depocentre development, the rise and fall of salt structures, and external forces' impact on subsurface salt movement. The 3D reconstruction procedure is radically different from classic backstripping in limiting palinspastic restoration to the salt overburden, followed by volume-constant balancing of the salt substratum. The unloading approach can serve as a template for analysing other salt basins worldwide and provides a stepping stone to physically sound fluid-dynamic models of salt tectonic provinces.

Abstract. Archimedes' principle states that the upward buoyant force exerted on a solid immersed in a fluid is equal to the weight of the fluid that the solid displaces. In this 3D salt-reconstruction study we treat Zechstein evaporites in the subsurface of the Netherlands, Central Europe, as a pseudo-fluid with a density of 2.2 g/cm3, overlain by a lighter and solid overburden. 3D sequential removal (backstripping) of a differential sediment load above the Zechstein evaporites is used to incrementally restore the top Zechstein surface. Assumption of a constant subsurface evaporite volume enables the stepwise reconstruction of base Zechstein and the approximation of 3D salt-thickness change and lateral salt re-distribution over time. The salt restoration presented is sensitive to any overburden thickness change irrespective if caused by tectonics, basin tilt or sedimentary process. Sequential analysis of lateral subsurface salt loss and gain through time based on Zechstein isopach difference maps provides new basin-scale insights into 3D subsurface salt flow and redistribution, supra-salt depocentre development, the rise and fall of salt structures, and external forces' impact on subsurface salt movement. The 3D reconstruction procedure described can serve as a template for analyzing other salt basins worldwide and provides a stepping stone to physically sound fluid-dynamic models of salt tectonic provinces.