The shallow subsurface geology of the southern North Sea (UK) : an updated assessment using data from offshore wind farms

Offshore wind development across the UK Continental Shelf (UKCS) has undergone rapid expansion since the early 2000s, becoming a cornerstone of the UK’s energy strategy. As of the time of writing, offshore wind has generated 52.9 TWh of electricity in the past 12 months (The Crown Estate, 2025), enough to supply approximately 14.6 million homes with power for a year. The growth of this sector is underpinned by an increasing volume of high-resolution geophysical, geotechnical and geological data acquired from the marine environment. This increase in data and reporting across the southern North Sea (SNS) encourages a renewed assessment of the shallow subsurface geology of the area. For this reason, BGS has instigated a compilation of recent observations of the region’s shallow geology, based on data and reporting from multiple offshore wind farm (OWF) sites. This report introduces the first integrated chronostratigraphic framework for the region, synthesising open-source geological and palaeo-environmental data from OWF sites. This framework is presented with reference to the existing stratigraphic model as well as recent research advances. The aim is to establish a baseline stratigraphic correlation across OWF developments in the SNS, providing a foundation for future refinement and collaborative research. This study provides an important first step by delivering an updated assessment of the Quaternary, Pliocene and bedrock sequences of the SNS. We hope this report and dataset will enable a full revision of the regional stratigraphy in the future. However, it is important to acknowledge that the framework relies on limited absolute dating of multiple geological formations for the deeper stratigraphy of many sites and there is a general absence of open access biostratigraphic data available. This report identifies the following recommendations: • update and improve the stratigraphic model of the SNS by harmonising and unitising offshore stratigraphy across OWFs • improve offshore mapping and prediction of detailed lithofacies associations by formation, underpinned by detailed classification codes such as geological setting • integrate geotechnical data that categorises the subsurface by geological formation and geological setting linked to facies type to create an adaptive geological-geotechnical reference database capable of returning formation-conditioned CPT parameter ranges and probabilistic soil type predictions • develop an age dating and unified biostratigraphic database to enhance and support a more robust understanding of the subsurface Together, these improvements would create high-quality datasets that support numerous future offshore applications for future studies across the UKCS. These include the siting and construction of offshore energy infrastructure, sustainable management of marine resources and continued applied research advancement.