Kinematics and Dynamics of Multi-stage Salt Diapirs in the Dutch-Central Graben, Southern North Sea

Salt structures are of significant economic and societal interest for the energy industry, forming hydrocarbon traps and serving as potential sites for energy storage. The thorough evaluation of multi-stage salt structures and the salt-encasing sedimentary sequences is paramount to mitigate risks and uncertainties in subsurface exploration. Utilizing a recently published methodology applied to a Two-Way-Travel-Time 3D seismic reflection dataset, time-structural, and isochron maps, this tectonostratigraphic study validates regional findings in a local context within the Dutch-Central Graben, Southern North Sea. This study subdivides the Dutch-Central Graben into five structural domains, analyzes the relationship between seismic stratigraphic sequences and sedimentary thickness variations, and provides a deeper understanding of salt diapirism. The study reveals that approximately 53% of salt diapirs in the Dutch-Central Graben were triggered as salt anticlines in the main central graben domain and in the east margin and shoulder domains. Additionally, 36% were triggered as reactive diapirs across the Dutch-Central Graben and 11% as passive diapirs in the west shoulder, east margin, and main rift graben domain. The tallest salt diapirs displayed up to five local stages of salt diapirism across three regional phases of tectonic evolution: rift, contraction/inversion, and post-tectonic. Further, the study evinces that fault communication between nearby salt structures is more common during the salt anticline stage in the rift phase of tectonic evolution in the Southern North Sea, and that radial faults are not characteristic of a particular diapiric stage. These results enhance the understanding of the spatio-temporal variability of salt diapirs on a local scale, the development and evolution of salt-related radial and concentric faulting and provide a useful framework for analyzing salt structures at different scales.