Tectono-stratigraphic evolution of salt-influenced normal fault systems: an example from the Coffee-Soil Fault, Danish North Sea

• Published in: Journal of the Geological Society Vol. 180; no. 6; p. 1
• Main Authors: Duffy, Oliver B., Gawthorpe, Rob L., Docherty, Matthew
• Format: Journal Article
• Language: English
• Published: Oxford The Geological Society of London 03-11-2023; Geological Society Publishing House
• Subjects: Coffee; Evolution; Fault lines; Hanging walls; Hydrocarbons; Load distribution; Salts; Soil; Soils; Stratigraphy; Structural geology; Tectonics; North Sea
• ISSN: 0016-7649; 2041-479X
• DOI: 10.1144/jgs2023-016

We explore how the relationships between fault activity, salt movement and sediment loading affect the stratal geometry of the hanging wall throughout the evolution of a salt-influenced normal fault system. We examine a c. 65 km long portion of the Coffee-Soil Fault System in the Danish North Sea, the hanging wall of which has been partially influenced by a pre-rift unit of mobile salt. To constrain the tectono-stratigraphic evolution of this fault system, we combine structural observations with seismic stratigraphic analysis of the hanging wall growth strata. We find that the hanging wall of the Coffee-Soil Fault System shows major depocentre shifts through time, along with marked variability in the along- and across-strike stratal geometries. We explain how the development of these characteristics is influenced by: (1) the segmentation and linkage history of the fault system; (2) the evolution of the salt-cored cover monoclines above blind basement fault segments; and (3) changes in the location and rate of accommodation generated by the load-driven withdrawal of salt up the dip-slope of the hanging wall and by fault-related subsidence. Our findings have implications for structural and stratigraphic studies in salt-influenced rift basins, as well as for understanding the potential distribution of geo-storage and hydrocarbon reservoirs in such settings.