Post-garnet high-pressure transition: Effect of heterogeneous laser heating and introduction of some new techniques
Yagi, Takehiko; O'neill, Bridget; Kondo, Tadashi; Miyajima, Nοbuyοshi; Fujino, Kiyοshi
European Journal of Mineralogy Volume 9 Number 2 (1997), p. 301 - 310
published: Jun 26, 1997
manuscript accepted: Nov 26, 1996
manuscript received: May 31, 1996
ArtNo. ESP147050902007, Price: 29.00 €
Abstract The post-garnet high-pressure transition has been studied above 25 GPa using several high-pressure apparatus. Recovered samples were characterized using SEM and TEM coupled with energy-dispersive electronmicroprobe analysis, and powder X-ray diffraction. Combined with the results of previous work, it became clear that, in the case of garnet, the resulting high-pressure phases differ considerably depending on the details of the high-pressure experiments. The current study shows that heterogeneous heating by YAG laser in the diamond anvil cell may be responsible for some of the complexity of previous results. Much more uniform heating of the sample is now possible using a resistance furnace in a Drickamer-type apparatus or CO2-laser heating in a diamond-anvil cell. The results of the current experiments indicate that end-member pyrope garnet transforms into a mixture of perovskite and corundum phases in the pressure range of about 30 GPa.