Major element data of carbonates from ultramafic rocks recovered from the southern wall of the Atlantis Massif, IODP Expedition 357

Major element analyses of carbonates (aragonite, calcite, dolomite, magnesite) from seven drill cores recovered during IODP Expedition 357 (October to December 2015) on the Atlantis Massif, Mid-Atlantic Ridge provide information on the genesis of carbonate minerals in the oceanic lithosphere. The samples were examined to understand the mechanism that drives carbonate formation and help find a solution to stabilize atmospheric CO2 and reduce global warming. The measurements were performed at the ETH Zurich, Institute of Geochemistry and Petrology from 2017 to 2020 using a five-spectrometer JEOL JXA-8200 and JEOL JXA-8230 Electron Probe Microanalyser operating in wavelength-dispersion mode. Elements analyzed are Si, Mg, Al, Ba, Ca, Fe, Mn, and Sr, and the concentrations were quantified based on natural and synthetic standards. CO2 was calculated assuming stoichiometric mineral compositions.