This paper presents depth maps for eight key horizons and seven thickness maps covering the onshore and offshore areas for the Late Permian to recent sedimentary section of the Netherlands. These maps, prepared in the context of a TNO regional mapping project, are supported by nine regional structural cross sections and a table summarizing the timing of tectonic activity from Carboniferous to recent. These new regional maps enable the delineation of various structural elements but also reveal the development of these elements through time with improved detail. Since the latest Carboniferous the tectonic setting of the Netherlands changed repeatedly. During successive tectonic phases several pre-existing structural elements were reactivated and new elements appeared. The various identified regional structural elements are grouped into six tectonically active periods: Late Carboniferous, Permian, Triassic, Late Jurassic, Late Cretaceous and Cenozoic. This study demonstrates that many structural elements and fault systems were repeatedly reactivated and that a clear distinction exists between long-lived elements, such as the Roer Valley Graben, and short-lived structural elements, such as the Terschelling Basin.

A seismic velocity model is necessary to map depth and thickness of subsurface layers interpreted from seismic reflection images. We have built a seismic velocity model (VELMOD-1) for the entire Netherlands area, both onshore and offshore, using non-confidential data (sonic logs, time-depth pairs, lithostratigraphic marker depths and downhole position data) of 720 boreholes in DINO - National Geoscientific Portal, and a preliminary isochore map (in seismic traveltime representation) of the layer of the Zechstein Group. The model is based on the Vint-zmid method applied to the following lithostratigraphic layers: Lower, Middle and Upper North Sea groups; Chalk Group; Rijnland Group; Schieland, Scruff and Niedersachsen groups; Altena Group; Lower and Upper Germanic Trias groups; Upper Rotliegend Group; and Limburg Group. Per layer, the linear least squares approximation, applied to Vint as a function of zmid, provides parameters V0 and K for a linear velocity function V(z) = V0 + K · z. In VELMOD-1, K is constant, at least at the scale of structural elements, whereas V0 varies with location. At borehole locations, V0 is calibrated such that traveltime through the layer according to the linear velocity model equals the traveltime according to the borehole data. A kriging procedure is applied to the calibrated V0(x, y)-values resulting in an estimated V0-value at any other location. The model V0-values were determined on an areal grid with cells of 1 km × 1 km. On the same grid, kriged interval velocities constitute the model for the Zechstein Group. These interval velocities stem directly from interval velocities at borehole locations; at other positions they are also dependent on the thickness (in terms of seismic traveltime isochores) of the layer of the Zechstein Group. Maps are presented of the distributions of both V0 and its standard deviation for two layers: that of the Chalk Group and that of the Lower and Upper Germanic Trias groups.

In the ‘Winterswijksche Steen- en Kalkgroeve’, situated in the eastern Netherlands, Lower Muschelkalk limestones are quarried. A ca. 30 m wide area in the quarry face showing fragmented rock material in chaotic accumulation in between stratified Muschelkalk sediments was interpreted until now to be the result of karstification or tectonic fragmentation. The present investigation indicates that it originated as a subrosion pipe fill that formed by continuous upsection collapse which commenced in the Röt gypsum and anhydrite beds more than 200 m below. The pipe fill is dated probably to one of the Quarternary interstadials when these rocks were dissolved by groundwater at even greater depths.