The Geo-Assessment Matrix (the Matrix) is a pan-European dataset highlighting the key geological features and associated engineering constraints for Offshore Wind Farm (OWF) development. Such geological features include: lithology; biogenic processes; mass flow processes; fluid flow; morphology and geomorphology associated with glacial, coastal, fluvial and marine settings. There is currently no universally adopted methodology or classification system to assess ground conditions at OWF sites. This lack of standardisation makes it difficult to compare siting conditions across different regions in Europe. The Geo-Assessment Matrix introduces a unified methodology designed to address these challenges. Results provide data attributions that can be used to create pan-European geological maps to better understand the geological constraints of the subsurface for offshore development. The Matrix is useful for stakeholders such as research institutes (Geological Surveys), marine spatial planners, government agencies and OWF developers. A matrix style is adopted providing a structured comparison of geological and engineering constraints for the development of different OWF foundation types (piles, suction caisson, gravity based structures – GBS, and cables). A final qualitative unmitigated geological constraint score is provided for evaluating the suitability of different seabed conditions: ‘Higher’, ‘Moderate’ and ‘Lower’ constraints. As this is a qualitative assessment, they are comparative terms, permitting categories that reflect the relative difference. - Higher constraint: Geological features may present significant challenges to engineering solutions. These are typically (but not limited to) geohazards, such as organic soils, pockmarks, active sedimentary systems, slope instability and soft sediments. - Moderate constraint: Geological features may be suitable for foundations, however, likely need additional engineering design/solutions mitigation measures. These are typically variable sedimentary features, such as heterogeneous sediments, mobile sediments, weak bedrock and gravel. - Lower constraint: Geological features are likely suitable for foundations. These are typically more predictable sediments, such as homogeneous or layered sediments or strong bedrock. Note that some features may still require mitigation measures. Outputs from the Matrix help to inform early decision-making and spatial planning by highlighting areas of relative geological constraint in countries during the early stages of offshore wind development.

We collected major element, trace element and Nd isotopes of cumulate plagioclase and clinopyroxene in lower crustal gabbros from Hess Deep oceanic crust (~2°15'N, 101°30'W) to investigate the Nd isotopic heterogeneity of melts delivered to a complete section of Hess Deep oceanic crust, accreted at the fast-spreading (133 mm/yr) East Pacific Rise (EPR). These data are presented in Cooper et al. (2025) (https://doi.org/10.1130/G52872.1). Elemental maps of 58 samples were initially obtained prior to selecting a subset of 25 samples for in-situ microanalysis. We targeted the Nd isotope record of cumulate plagioclase and clinopyroxene from lower crustal gabbro samples, representing early crystallisation products of melts delivered to the crust. These samples were collected in several expeditions: Ocean Drilling Program (ODP) Leg 147; RSS James Cook cruise JC21; Integrated Ocean Drilling Program (IODP) Expedition 345 (Site U). Combined, these studies provide the most complete composite section of fast-spreading EPR crust to date (stratigraphic depth of 4350 m to 25 m). In our study, we selected 25 samples for in situ Nd isotope microanalysis, covering the range of mineralogy and textural diversity, and over the full stratigraphic depth. For a comparison to local MORB compositions, we selected a set of 13 upper-crustal sheeted dikes collected on the RSS James Cook cruise JC21. Our data reveal that the mantle is heterogeneous at the scale of melt extraction, and the crystal record from the lower crust shows greater 143Nd/144Nd heterogeneity than the overlying MORB. Hence, Pacific MORBs do not reflect the full heterogeneity of their mantle source, and some aggregation of melts occurs within the crust. Data was collected between 2020 and 2023 by George Cooper, Johan Lissenberg and Max Jansen at Cardiff University, UK, as part of NERC Grant NE/T000317/1:HiDe: A Highly Heterogeneous Depleted Upper Mantle? Mineral isotopic analyses were performed on a Thermo Scientific TRITON Plus at the Vrije Universiteit in Amsterdam. The long-term average and reproducibility (2019–2022) for the JNdi-1 standard is 0.512094 ± 0.000011 2 SD (standard deviation; n = 28) with 1011Ω resistors (used for clinopyroxene) and 0.512105 ± 0.000044 2 SD (n = 45) with four 1013Ω resistors (used for plagioclase). Full methodology can be found within the supplemental Material of Cooper et al. (2025) at https://doi.org/10.1130/GEOL.S.28485770 The DOI is a supplement to https://doi.org/10.1130/G52872.1 Methodology: https://gsapubs.figshare.com/articles/journal_contribution/Supplemental_Material_Crustal_versus_mantle-level_aggregation_of_heterogeneous_melts_at_mid-ocean_ridges/28485770?file=52665137

Morphometric data, produced and used, to describe Globigerinoides rublobatus n. sp., a new species of fossil planktonic foraminifera from the Pleistocene Indian Ocean. We used image analysis and morphometry of 860 specimens from International Ocean Discovery Program Site U1483 in the tropical Indian Ocean to document morphological variability in the new species and related taxa.