The study by Gale et al. (2013) provides a comprehensive analysis of the mean composition of mid-ocean ridge basalts (MORB). The authors compiled a global dataset of major elements, trace elements, and isotopes from 771 ridge segments, including their mean depth, length, and spreading rate. This dataset allowed for the calculation of average compositions for each segment, which were then weighted by segment length and spreading rate to reduce bias from uneven sampling. The study introduced a revised nomenclature for MORB, defining "ALL MORB" as the total composition of the crust apart from back-arc basins, "N-MORB" as the most likely basalt composition encountered >500 km from hotspots, and "D-MORB" as the depleted end-member. The results show that "ALL MORB" and "N-MORB" are more enriched than previously estimated normal ridge basalts. The average composition of back-arc spreading centers requires higher extents of melting and greater concentrations of fluid-mobile elements, reflecting the influence of water on back-arc petrogenesis. The study also re-evaluated several problems in global geochemistry, such as the K/U ratio and the Sm/Nd and 143Nd/144Nd ratios, providing constraints on the hypothesis that Earth has a non-chondritic primitive mantle. The methodology used in this study, with segment length and spreading rate weighting factors and meaningful confidence estimates, provides the most reliable estimate of average MORB to date.The study by Gale et al. (2013) provides a comprehensive analysis of the mean composition of mid-ocean ridge basalts (MORB). The authors compiled a global dataset of major elements, trace elements, and isotopes from 771 ridge segments, including their mean depth, length, and spreading rate. This dataset allowed for the calculation of average compositions for each segment, which were then weighted by segment length and spreading rate to reduce bias from uneven sampling. The study introduced a revised nomenclature for MORB, defining "ALL MORB" as the total composition of the crust apart from back-arc basins, "N-MORB" as the most likely basalt composition encountered >500 km from hotspots, and "D-MORB" as the depleted end-member. The results show that "ALL MORB" and "N-MORB" are more enriched than previously estimated normal ridge basalts. The average composition of back-arc spreading centers requires higher extents of melting and greater concentrations of fluid-mobile elements, reflecting the influence of water on back-arc petrogenesis. The study also re-evaluated several problems in global geochemistry, such as the K/U ratio and the Sm/Nd and 143Nd/144Nd ratios, providing constraints on the hypothesis that Earth has a non-chondritic primitive mantle. The methodology used in this study, with segment length and spreading rate weighting factors and meaningful confidence estimates, provides the most reliable estimate of average MORB to date.