The RISeR cores: unexpected and extensive Middle Pleistocene terrestrial stratigraphy in the southern North Sea

Abstract. The Rates of Interglacial Sea-level Change and Responses (RISeR) project, funded by the European Research Council, seeks to interrogate Earth system responses to Quaternary climate variability using sedimentary archives preserved in the southern North Sea. Fundamental to the project is the retrieval of five new marine cores, sited to intersect sediments associated with Middle and Late Pleistocene formations identified through earlier regional stratigraphic research and detailed seismic information acquired at the Hollandse Kust Zuid (HKZ) offshore wind farm in the Dutch North Sea (Southern Bight). Drilling of the five cores was carried out in July 2020 using Fugro's geotechnical drilling vessel, MV Normand Flower. The new cores total ca. 62 m of retrieved sediment, reaching a maximum drill depth of 54.3 m below the lowest astronomical tide. Here, we present the lithostratigraphy of the RISeR cores and combine this new sedimentary dataset with high-resolution seismic reflection data. This reveals the preserved Middle and Late Pleistocene stratigraphy of the HKZ wind farm to be predominantly terrestrial and partly coastal and shallow marine.