Figure F2. Total alkalis vs. silica (Na2O + K2O vs. SiO2) and alkaline discrimination diagrams for basement rocks from the CRISP-A transect drilled during Expeditions 334 and 344 (Le Maitre, 1989). The line dividing alkalic and tholeiitic series is from Irvine and Baragar (1971). The fields for north, central, and south Cocos Ridge (including seamounts in the north) are from Hoernle et al. (2000).
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