Figure 3.
Diverse H2O loss calculated as a function of depth for oceanic lithosphere and sediment subducting into each of Earth’s modern subduction zones (the “Tokyo Subway Map” from van Keken et al., 2011). The warmest subduction zones lose most of their H2O beneath the forearc. All subducting slabs lose significant water when the slab comes into contact with the hot overlying mantle wedge (in these models, at 80 km depth). For many slabs (e.g., Kamchatka, Calabria) further dehydration is minor. Other slabs (e.g., Chile) continue to dehydrate significantly with increasing depth principally due to the dehydration of the uppermost mantle. A few slabs (e.g., Marianas) are very cool, and far less H2O is lost to even 230 km depths.