Fig. 3: Temporal changes in geochemistry of Fagradalsfjall whole-rocks.
a TAS diagram after ref. 49 with comparative literature data for Reykjanes Peninsula (RP) basalts. Fagradalsfjall whole-rock lava samples are tholeiitic basalts. b–f Timeline plots of MgO (b), K2O/TiO2 (c), Nb/Zr (d), Zr/Y (e), and Th/Yb (f). In b, the mean MgO wt.% for RP basalts is shown as a black horizontal line and the height of the grey box corresponds ±1 SD; for all other plots the full range of literature data is shown. In panel d, enriched samples are defined as having a Nb/Zr ratio >0.08 (after ref. 28). In panel f, mantle end-members are indicated after ref. 50. Note that there are relatively few Th/Yb ratios available for RP basalts in the literature. The dashed vertical lines in all panels indicate the timing of additional vent openings; the second vent (#2) and the last new vent (#6) as labelled in panel b. Abbreviations: EMORB enriched mid-ocean ridge basalt, NMORB normal mid-ocean ridge basalt, OIB ocean island basalt, RP Reykjanes Peninsula. Uncertainty on major and trace element data is estimated at better than 5% and 10%, respectively (shown as error bars). Where no error bars are visible, uncertainty is smaller than symbol size. Literature data are taken from refs. 25,28,51,52,53,54,55,56.
