Abstract
The pressure-temperature conditions of the reactions governing the high-pressure stability of talc were investigated in experiments on the bulk composition Mg3Si4O10(OH)2 + H2O at 2.9-6.8 GPa, 650-820°C, using piston-cylinder and multianvil apparatus. The reaction talc = enstatite + coesite + vapor was bracketed between 800 and 820°C at 2.90-2.95 GPa and between 770 and 780°C at 3.77-4.02 GPa. The lower-pressure bracket, which is just above the quartz-coesite phase transition, is consistent with some of the previous brackets on the reaction talc = enstatite + quartz + vapor and with the position of the talc dehydration reaction calculated using THERMOCALC v2.4. This revised version of THERMOCALC incorporates new compressibility and thermal expansivity data for talc. -from Authors
Original language | English |
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Pages (from-to) | 998-1003 |
Number of pages | 6 |
Journal | American Mineralogist |
Volume | 80 |
Issue number | 9-10 |
Publication status | Published - 1995 |