Fig. 4: Sequential breakdowns from pyrophyllite (and kaolinite) and its impact on H2O flux along subduction zone.
From: A role for subducting clays in the water transportation into the Earth’s lower mantle
a Depths of sequential breakdowns from pyrophyllite (and kaolinite) are marked in a schematic subduction diagram. Insets are the schematic illustrations of the fluid migration pathways in shallow and intermediate subduction interfaces (modified after Konrad-Schmolke et al. (2011)). The phase assemblages from pyrophyllite are: a (prl), b (gbs + dsp + coe), c (dsp + coe), d (toz + dsp + coe/stv), e (del + Egg + stv), and from kaolinite: a’ (kao), b’ (sh-kao), c’ (pi + coe), d’ (dsp + pi + coe), e’ (toz-II + stv) (Supplementary Table 5). *Phase abbreviations: pyrophyllite (prl), gibbsite (gbs), diaspore (dsp), coesite (coe), topaz (toz), stishovite (stv), phase Egg (egg), δ-AlOOH (del) and kaolinite (kao), super-hydrated kaolinite (sh-kao), phase-pi (pi), topaz-II (toz-II). b Estimated net water contents (wt% H2O) and net crystalline density (g/cm3) of the respective phase assemblages from pyrophyllite. Values in the parenthesis are the estimated H2O flux from pyrophyllite. c H2O flux of a subducting slab composed of sediments (S, pink boxes; filled in pink for ASH system and filled in green for non-ASH system), crust (C, navy boxes), and hydrated mantle (M, gray boxes) layers. Depth ranges for C and M down to <230 km are shown in parenthesis. The summed H2O flux of S, C, and M layers at the surface is set to 100% to show the efficiency of H2O transportation at depths. The pie charts in the right panel show H2O transport capacity of each layer per unit volume.
