Figure F8. Selected minor and trace element ratios vs. Mg#. Fractionation and alteration processes alone cannot reproduce all of the geochemical variability observed. A. K2O. Alteration and/or differences in partial melting increase alkali variability at given Mg#. B. V/TiO2 is expected to be controlled by original magma composition and proportion of fractionating Fe-Ti and/or clinopyroxene phases. The ratio V/TiOd is approximately constant over a range of Mg# for Subunit 4A but is more scattered for Subunit 4B, tending to increase with increasing Mg#. These relationships suggest that Subunits 4A and 4B were not generated from a common melting event at a single time. Fractionation is not responsible for the bimodal distribution of (C) (La/Sm)N and (D) Hf/Ta ratios. Mg# = [Mg / (Mg + Fe+2)]. Includes data from Kimura, Silver, Blum, et al. (1997). Also shown are data from Leg 206, the fast-spreading East Pacific Rise deep reference site (Wilson, Teagle, Acton, et al., 2003).

Figure F8. Selected minor and trace element ratios vs. Mg#. Fractionation and alteration processes alone cannot reproduce all of the geochemical variability observed. A. K₂O. Alteration and/or differences in partial melting increase alkali variability at given Mg#. B. V/TiO₂ is expected to be controlled by original magma composition and proportion of fractionating Fe-Ti and/or clinopyroxene phases. The ratio V/TiO_d is approximately constant over a range of Mg# for Subunit 4A but is more scattered for Subunit 4B, tending to increase with increasing Mg#. These relationships suggest that Subunits 4A and 4B were not generated from a common melting event at a single time. Fractionation is not responsible for the bimodal distribution of (C) (La/Sm)_N and (D) Hf/Ta ratios. Mg# = [Mg / (Mg + Fe⁺²)]. Includes data from Kimura, Silver, Blum, et al. (1997). Also shown are data from Leg 206, the fast-spreading East Pacific Rise deep reference site (Wilson, Teagle, Acton, et al., 2003).