Figure 6. Variation of Ta/Nd with Th/Nb for the MORB-, OIB-and SSZ-type basaltic lavas from the Tethyan suture zone in western Turkey. The predicted mixing trend between MORB and OIB compositions defines the vertical trend comprising the compositional variations of the MORB- and OIB-type lavas from western Turkey, while the model prediction constituting the subduction influx into the depleted MORB mantle can account for the compositions of the lavas with SSZ geochemical signatures. End-member components shown in the figure are defined by 17 % melting of a depleted mantle source (A), 4 % melting of an enriched mantle source (B) and 20 % melting of a subduction-enriched mantle source (C).