... hydrous aluminosilicate minerals like phase π [Al 2 Si 2 O 7 (OH) 3 ] and topaz-OH can retain water up to ~8 GPa ( Wunder et al. 1993a , 1993b ; Schreyer 1995 ). Later, high-pressure experiments on synthetic oceanic sediment revealed that topaz-OH is stable at pressures from 8 to 12 GPa and transforms...

...Mainak Mookherjee; Wendy R. Panero; Bernd Wunder; Sandro Jahn Abstract Phase egg, [AlSiO 3 (OH)], is an aluminosilicate hydrous mineral that is thermodynamically stable in lithological compositions represented by Al 2 O 3 -SiO 2 -H 2 O (ASH) ternary, i.e., a simplified ternary for the mineralogy...

...Earl F. O'Bannon, III; Quentin Williams Abstract Topaz [Al 2 SiO 4 (F,OH) 2 ] is a subduction-related mineral that is found in metasediments and has a large pressure and temperature stability field. Here, we use luminescence spectroscopy of Cr 3+ to probe the Al site in topaz at pressures up to ~60...

... estimated the storage capacities of the various mineral reservoirs in the mantle. The 10 Å phase, Mg 3 Si 4 O 10 (OH)·H 2 O, is a mica-like dense hydrous magnesium silicate phase that occurs at 3–5 GPa as a breakdown product of serpentine and chlorite ( Yamamoto and Akimoto 1977 ). It is structurally...

... AlSi 3 OH = δ-AlOOH + SiO 2 (stishovite) and the evolution in the elastic moduli and sound velocities of hydrous minerals as a function of density. where λ 0 is the laser wavelength of 532 nm, θ is the external scattering angle of 48.3(1)° calibrated using water as a standard. * E...

... in the Al 2 O 3 -SiO 2 -H 2 O system. They designated this pure hydroxyl end-member as “topaz-OH” (synthetic OH analogue of topaz, hereafter referred to as topaz-OH without the quotation marks). Northrup et al. (1994) determined the structure of topaz-OH from single-crystal X-ray diffraction data...

... 2 O 7 (OH) 3 ] are stable to pressures of 6 GPa, and these phases react with SiO 2 to form hydrous topaz [Al 2 SiO 4 (OH) 2 ; Wunder et al. 1993a , b ], which is stable up to 11 GPa at 1000°C. At higher pressures, topaz-OH reacts with SiO 2 to form phase Egg [AlSiO 3 OH; Eggelton et al. 1979...

... observed in metamorphic rocks, (2) high-pressure hydrous phases such as DHMS (Fig. 1 ), K-richterite, topaz-OH, and phase Egg, and (3) middle-pressure hydrous minerals such as phlogopite, antigorite, Mg-sursassite and 10 Å phase in peridotite, lawsonite in basalt, and phengite in sediment. The last group...

...\ talc\ (Mg_{3}Si_{4}O_{10}(OH)_{2})\ +\ chlorite\ (Mg_{5}Al_{2}Si_{3}O_{10}(OH)_{8})\\&&+4\ Mg-chloritoid\ (MgAl_{2}SiO_{5}(OH)_{2})\\&&=\ 5\ pyrope\ +\ 10\ H_{2}O\end{eqnarray*} \end{document} (4) \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb...

... the calibrated model for the fully oxidized Al and Si parameters. Some species were expected to give good results: Al(OH) 3 (bayerite), AlOOH (boehmite), Al 4 Si 4 O 10 (OH) 8 (kaolinite), and SiO 2 (tridymite, moganite, and seifertite). However, we had no expectations about how the model would perform...

... on LDA (α LDA ) is in very good agreement with the recent synchrotron XRD study on pargasite amphibole, which shows 2.7 × 10 -5 K -1 at 300 K and 0 GPa ( Comboni et al. 2017 ) ( Fig. 3 ). It should be noted that pargasite [NaCa 2 (Mg 4 Al)(Si 6 Al 2 )O 22 (OH) 2 ] and tremolite are both calcic...

...Stefano Poli; Max W. Schmidt Figure 1. Chemography of the CaO-Al 2 O 3 -SiO 2 -H 2 O system projected from vapor. an: anorthite; cor: corundum; cs: coesite; dia: diaspore; gr: grossular; ky: kyanite; law: lawsonite; ma: margarite; pi: phase Pi; qz: quartz; pre: prehnite; top-OH: topaz-OH; v...