Fig. 4: Trace element ratios in whole-rock samples from the 2021 Fagradalsfjall eruption.
a Zr versus Nb/Zr diagram after ref. 25 showing that early erupted samples are less enriched than later erupted ones. Fagradalsfjall samples are notably distinct from Reykjanes Ridge (RR) basalts reported in ref. 57. b Zr/Y versus Nb/Y diagram showing that while Fagradalsfjall samples plot within the Iceland array, they are compositionally distinct from NMORB and Mid-Atlantic Ridge (MAR) south of 60.5°N (reference fields drawn after ref. 58). c Zr/Y versus Nb/Zr diagram showing the Depleted Iceland Plume component (DIP), two depleted mantle components (D1 and D2), the main basaltic component (“E” for Eldgjá), the alkalic component (“S” for Snæfellsnes), and mixing curves after ref. 10. The samples from the 2021 Fagradalsfjall eruption reflect an apparently co-equal mixture of an enriched mantle component and a more depleted mantle endmember in magma genesis. d Nb/Yb versus Th/Yb diagram after ref. 50 showing that Fagradalsfjall samples plot dominantly around E-MORB. e MgO versus Nb/Zr diagram after ref. 59 showing enriched (pyroxenite) and depleted (peridotite) endmember mantle sources after ref. 60. Samples that plot between these end-members reflect melt mixing and concurrent crystallisation. Abbreviations and data uncertainties are given in Fig. 3. Sources of literature data are the same as in Fig. 3 with additional data from ref. 57.
