Analyses of major elements (presented as weight percent oxide) in volcanic rocks from Mt. St. Helens, Washington, USA. The data table includes sample descriptions. More detailed sample descriptions are given in Blundy et al., (2008). Blundy, J., Cashman, K.V. and Berlo, K. (2008) Evolving magma storage conditions beneath Mount St. Helens inferred from chemical variations in melt inclusions from the 1980-1986 and current (2004-2006) eruptions, in: Sherrod, D.R., Scott, W.E., Stauffer, P.H. (Eds.), A volcano rekindled: the renewed eruption of Mount St. Helens, 2004-2006, Reston, VA, pp. 755-790.

Major and trace elemental analysis of sulphide samples from the Beebe Vent Field. Geographical area - Beebe Vent Field, Cayman Trough, 18°32.798N,81°43.092W

Major and trace element data of lava and tephra samples from the 2021 Tajogaite eruption. Major and select trace element collected by XRF, trace elements collected by ICPMS, both at the University of Granada. Data collected as part of NERC Urgency Grant led by K Chamberlain (Liverpool), in collaboration with M Pankhurst (INVOLCAN), J Scarrow (Granada), D Morgan (Leeds), J Hickey (Exeter), D Neave (Manchester), for understanding how eruptions begin, evolve and end. Samples analysed span the entire September - December 2021 eruptive sequence of Tajogaite, and data were collected between December 2021 and August 2022.

This dataset contains geochemical measurements which quantify the major and trace element concentrations of Precambrian (Proterozoic) and Paleozoic (541–251 Mya) mudstones. Sampled mudstones are listed under their formation name, with information on the locations of each outcrop belt and further details on lithological characteristics, including environment of formation, freely available on the British Geological Survey Lexicon of named rock units (https://www.bgs.ac.uk/technologies/the-bgs-lexicon-of-named-rock-units/) and Government of Canada weblex (https://weblex.canada.ca/weblexnet4/weblex_e.aspx), for UK and Canadian samples, respectively. Stratigraphic age is given in accordance to the GSA geological timescale v.5.0. Following sampling, specific methodologies for preparation for major and trace element analysis, conducted on an Agilent 5100, are provided in the Methodology. The data was collected to understand changes in weathering intensity coeval with the Paleozoic expansion of land plants. The major element data was needed to: 1) determine how much sample was required for subsequent Lithium isotope analyses (data from which are separately uploaded to the repository); and 2) to ensure similarity of source between samples compared across our study. The tabulated major element analyses were compared at different temporal stages of plant evolution through the Paleozoic. Samples were collected by the University of Cambridge. Major element data was obtained by William McMahon, and supervised by Edward Tipper and Mohd Tarique and Emily Stevenson.

Major and trace element data for olivine- and plagioclase-hosted silicate melt inclusions, their host minerals, and associated matrix glasses, from Midfell, Snaefellsjokull and Oraefajokull, Iceland. Melt inclusion compositions are provided as measured, and corrected for post-entrapment crystallization. Reflected light images of the melt inclusions.

The dataset consists of a spreadsheet containing whole rock geochemistry (Major and trace elements, Hf isotopes) from 7 samples and zircon U-Pb, O, Hf isotope and trace elements compositions (>200 spots on zircons from 7 samples) analysed by Ion Microprobe (NERC EIMF) and MC-LA-ICP-MS (NIGL). The samples are Eoarchaean amphibolite-facies mafic gneisses and a pegmatite as well as granulite-facies mafic gneiss and migmatite (melano- and leucosome) from the Kapuskasing uplift in Ontario, Canada.

Mineral and glass geochemical analyses (spot analyses) of samples recovered during IODP Expedition 398 (Site U1595). Site U1595 (proposed Site CSK-08B) is located in the southern basin of the Santorini caldera at 291 meters below sea level (mbsl). It was drilled in three holes (U1595A-U1595C) to a maximum recovery depth of 127.0 meters below seafloor. Some data files also contain SEM-BSE images of volcanic ash particles. Abbreviations used: n.d. = not determined; b.d. = below detection. Detection limits for volatiles in glass: Cl = 57 ppm, F = 140 ppm, S = 56 ppm Mineral and glass geochemical compositions were determined by electron probe micro-analysis, using facilities at the Natural History Museum London and at the University of Leeds. SEM-BSE images were generated at Keele University. Data analysis was supported by NERC - UK IODP Phase 4 Moratorium Award, NERC Grant NE/X016374/1, Ralf Gertisser. For sample context, see: https://publications.iodp.org/proceedings/398/398title.html https://doi.org/10.14379/iodp.proc.398.109.2024

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

Major and trace element data for partial melts derived from high pressure-temperature experiments on a basaltic starting composition from the Ontong Java Oceanic Plateau.

The data comprises a multi-proxy dataset of 49 samples spanning approximately the time interval from 1.8-3.9 Ma according to the currently available shipboard age model from offshore the Limpopo River, southwest Indian Ocean. Data includes major and trace element chemistry and K-Ar ages from the clay fraction (<2um), radiogenic isotope geochemistry, stable isotopes of planktonic foraminifera Globigerinoides ruber. The data set is now online with a citable DOI, although with an embargo till September 2019, http://dx.doi.org/10.1594/IEDA/100719