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TAS classification diagram

Le Bas et al. (1986) Total Alkali–Silica volcanic classification. Sample-data preview for now — data input arrives when this folds into the workbench.

TAS — Le Bas et al. (1986) 40 45 50 55 60 65 70 75 0 2 4 6 8 10 12 14 16 SiO₂ (wt%) Na₂O + K₂O (wt%) Picro-basalt Basalt Basalticandesite Andesite Dacite Rhyolite Trachy-basalt Basaltictrachy-andesite Trachy-andesite Tephrite Basanite Phono-tephrite Tephri-phonolite Foidite Phonolite Trachyte Trachydacite ULTRABASIC BASIC INTERMEDIATE ACID series A series B

Field boundaries/vertices are the published Le Bas et al. (1986) Table 2 values. Cite the scheme when you use it.