Fig. 1: Experimental P-T conditions and in-situ X-ray diffraction patterns of pyrophyllite and its breakdown products along water-rich cold subduction geotherms.
From: A role for subducting clays in the water transportation into the Earth’s lower mantle
a The stability of pyrophyllite and its decomposition products at P-T conditions of cold slab surface geotherms (blue and green bands denote the regions of P-T conditions along the coldest and moderately cold slab surface geotherms, respectively, from W1300 model by Syracuse et al. (2010)). The error bars represent pressure and temperature uncertainty (see Supplementary Table 1). Continuous and dashed curves (upper panel) denote the geotherms of the subducting slab surfaces and corresponding slab Moho, respectively35. The geotherm models within the mantle transition zone (lower panel) have been extrapolated from the data by refs. 93,94. Straight black lines represent previously established phase boundaries of the aluminous phases and SiO2 polymorphs27,29,37,95,96,97,98,99. The horizontal dotted lines define the upper and lower boundaries of the mantle transition zone. b Representative X-ray powder diffraction (XRD) pattern of pyrophyllite and its products. The backgrounds of the XRD patterns have been subtracted prior to present (see Supplementary Figs. 1–7). Sequential formations of gibbsite, diaspore, topaz, kyanite, phase Egg, and δ-AlOOH are observed along the hydrous cold subduction geotherm, together with SiO2 polymorph (coesite or stishovite). *Phase abbreviations: pyrophyllite (prl), gibbsite (gbs), diaspore (dsp), coesite (coe), topaz (toz), kyanite (ky), stishovite (stv), phase Egg (egg), δ-AlOOH (del).
