This dataset contains the results of pore water chemistry, sediment composition, and dissolved oxygen content and includes X-ray diffraction (XRD) analysis of mineralogy, particle-size distribution, and clay surface area. The results, provided in a Microsoft Excel spreadsheet, were analysed from seafloor sediment samples collected as part of the Seabed Mining And Resilience To EXperimental impact (SMARTEX) Highlight Topic project funded by the UK Natural Environment Research Council (Whole Grant Reference NE/T003537/1) alongside other partner institutions in the project. Porewaters were extracted to analyse for trace metals (by ICP-MS), nutrients and alkalinity. Sediments were analysed for trace element geochemistry, loss on drying, particle size analysis and bulk and clay mineralogy by XRD. Dissolved oxygen measurements taken offshore immediately following core collection are also included. Separate datasets associated with the same project cover the geochemistry of nodules and physical property analysis of sediment collected to model the physical and temporal responses of deep-sea sediment to the compression caused by a deep-sea mining vessel. The samples were collected as part of Expedition JC241 2023 in the Ocean Minerals Company (OMCO) test mining site in the Clarion-Clipperton Zone of the Central Pacific Ocean. More information, location and the cruise report are available at www.bodc.ac.uk/resources/inventories/cruise_inventory/report/18136/
