The dataset consists of elemental compositions determined for olivine and spinel from 13 ocean islands, including Azores, Balleny, Cook-Austral, Crozet, Cape Verde, Fernando de Noronha, Galapagos, Juan Fernandez, Marquesas, Society, Tristan-Gough, Tahiti, and Trindade). These samples were loaned from Sedgwick Museum, University of Cambridge and National History Museum, London, except the Galapagos samples provided by D. Geist. Elemental compositions determined for three secondary standards (San Carlos olivine, MongOl olivine, and NHNM164905 augite) are also included in the dataset. The data were acquired using a Cameca SX100 electron microscope at the Department of Earth Sciences, University of Cambridge, in June, July, August and November 2021. The elements analysed include Mg, Si, Fe, Al, Ca, P, Cr, Mn, and Ni in olivine, and Mg, Si, Fe, Al, Ca, Cr, Mn, and Ti in spinel. Data acquired from each analysis were saved in four txt files, which are for oxide concentrations, elemental concentrations, standard deviation, and detection limit, respectively. The data for ocean island samples were used to calculate olivine crystallisation temperature and mantle potential temperature based on an aluminium-in-olivine thermometer and modelling of mantle melting. All data collected within the project duration are in this dataset.
