Geochemical composition, isotopic measurements and X-ray diffraction (XRD) results of Fe-oxyhydroxide and massive sulphide samples from Semenov Hydrothermal Field of the Mid-Atlantic Ridge during the RRS James Cook cruise JC224 (March-April 2022)

Discrete samples of Fe-oxyhydroxide and seafloor massive sulphide were collected on the RRS James Cook cruise JC224 (March - April 2022) to the Semenov Hydrothermal Field, a seafloor massive sulphide (SMS) system located within the Mid-Atlantic Ridge. Samples were collected using the ROV HyBIS (Murton et al., 2012) and a rock dredge. The samples were analysed onshore at the National Oceanography Centre and the University of Southampton for: (1) geochemical composition through Inductively Couple Plasma-Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), (2) mineralogical composition by X-ray diffraction (XRD), and (3) isotopic measurements through Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS). The datasets aim to improve understanding regarding the formation of Fe-oxyhydroxide samples at SMS systems and to determine the potential of Fe-oxyhydroxide as an additional resource at SMS systems. The data were collected as part of a PhD project funded under NERC's Ultramafic-hosted mineral Resource Assessment (ULTRA) project, grant reference NE/S004068/1, and the samples are stored at the National Oceanography Centre and Cardiff University.