[Na2O + K2O]/SiO2 - classification

Please note: Samples are classified only according to their alkali and silica content, irrespective of the rock name given in the original paper. Rock mode or other criteria are not regarded!

    TAS diagram foidite tephrite picrobasalt basalt trachybasalt b_trachyandesite phonotephrite tephriphonolite trachyandesite basaltic andesite andesite dacite trachyte rhyolite phonolite

after LE BAS et al. [1985]