2011/04/01 by X. Hu, X. Liu, Q. He +5
paper · doi:10.1180/minmag.2011.075.2.363
crossref issued 2011/04/01 · crossref published 2011/04/01 · crossref published-print 2011/04/01 · crossref created 2011/06/28 · crossref published-online 2018/07/05 · crossref deposited 2021/11/27 · crossref indexed 2026/07/29
Abstract The unit-cell parameters of andalusite and sillimanite have been measured by high- T powder X-ray diffraction up to 1000°C at ambient pressure. Within the temperature range investigated, all the unit-cell parameters varied smoothly, indicating no phase transition. The volume-temperature data were fitted with a polynomial expression for the thermal expansion coefficient (α T = a 0 + a 1 T + a 2 T -2 ). yielding a 0 = 2.55(2) × 10 –5 K –1 , a l = 0 and a 2 = 0 for andalusite, and a 0 = 1.40(4) × 10 –5 K –1 a 1 = 7.1(8) × 10 –9 K –2 and a 2 = 0 for sillimanite. Using the new thermal expansion data determined in the present study and compressional data from the literature, the P-T phase relations of the kyanite-andalusite-sillimanite system were calculated thermodynamically, with the invariant point located at ∼523°C and 3.93 kbar.