Figure F11. A. Total alkalis vs. silica, with Le Maitre et al.'s (1989) classification of volcanic rock types. Dashed line = Hawaiian tholeiitic and alkalic lava data division (Macdonald and Katsura, 1964; Macdonald, 1968), black arrow = compositional change caused by seawater alteration. All data are normalized to 100 wt% totals. B. TiO2 vs. Zr. ODP Leg 191 Site 1179 and Leg 198 Site 1213 data from Mahoney et al. (2005). OJP = Ontong Java Plateau (data of Tejada et al., 1996, 2002; Fitton and Godard, 2004), EPR = East Pacific Rise (data of Sinton et al., 1991; Bach et al., 1994; Mahoney et al., 1994), ESC = Easter Seamount Chain (data of Ray et al., submitted). Nazca Ridge and Easter Seamount Chain together form the hotspot trail of the Easter–Salas hotspot.
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