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DEVLI Project: Stratigraphy and Tectonostratigraphy of the Delfland and Vlieland subgroups, Upper Jurassic and Lower Cretaceous - Broad Fourteens Basin, West Netherlands Basin and neighbouring areas

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This report provides an update on the stratigraphy and tectonostratigraphy of the Upper Jurassic to Lower Cretaceous in southern part of the Dutch Offshore and in the western part of the Dutch onshore. The results provide new insights on the geology of the southern Dutch rift system with application for multiple resource applications.

This DEVLI project establishes a stratigraphic framework based on the integration of revisited legacy and newly acquired palynological information, as well as a new seismic interpretation effort focused on tectonostratigraphic megasequences (TMS-1 to TMS-4, as defined by Verreussel et al., 2018) mapping.

A large dataset consisting of 358 wells, all 2D and 3D seismic surveys available in the study area, core material and palynological data was analysed. The biostratigraphic, stratigraphic and structural results were integrated and presented in the form of three new Wheeler diagrams, five new core descriptions, six regional well/seismic panels and 16 new time structure and thickness maps. These documents include economically significant lithostratigraphic units such as the Alblasserdam, Delft Sandstone, Rodenrijs, Helder, Kotter, Helm, Logger members and the Nieuwerkerk, Breeveertien, Vlieland Sandstone formations.

The geological evolution of the rift was re-interpreted, including a new fault kinematic model anchored on a revised sequence stratigraphic framework. The Broad Fourteen and West Netherlands basins are described as transtensional dextral pull-apart basins with en-echelon basin sidewall faults and intrabasinal sigmoidal horsts and grabens systems, compartmentalizing the rift basins. The new stratigraphic framework clarifies the lithostratigraphic equivalencies across the rift system and its platforms. The integration of the structural results from the seismic mapping, gives the new chronostratigraphic framework a more realistic context, including the presence of unconformities and hiatuses, and clarifies the distribution and preservation of sand-rich intervals such, as the Delft Sandstone, Rijn, Logger and Kotter members.