Figure 3. Variations of secondary alteration indexes with distance from the ridge axis. A. Loss on ignition (LOI wt%). B. FeO/FeOt value. C. Modal abundance of secondary minerals (vol%). Solid circles = medium values; bars = variation range.

Figure 3. Variations of secondary alteration indexes with distance from the ridge axis. A. Loss on ignition (LOI wt%). B. FeO/FeO_t value. C. Modal abundance of secondary minerals (vol%). Solid circles = medium values; bars = variation range.