Fig. 3

Below-arc temperatures and melting potential in the Alaska subduction zone. The dry solidus for peridotite indicated by “H” (Hirschmann 2000) requires minor shifting in temperature to produce a source for primary magmas. “H-30” and “H-80” indicate shifts by 30 and 80\(^\circ\)C, respectively. This is the range between which magmas are created that generate on average 4 wt% H\(_2\)O which is the global average (Plank et al. 2013). a Thermal model for Alaska (similar to that in Syracuse et al. 2010) with regions that would experience melt if the dry solidus would be shifted by 30 and 80\(^\circ\)C. The triangle marks the location of the volcanic front at this cross-section. b Temperature below the arc and intersection with the shifted dry peridotite solidus