Back to Search
Start Over
New High‐Pressure Forms of Al2SiO5.
- Source :
- Geophysical Research Letters; 8/28/2018, Vol. 45 Issue 16, p8167-8172, 6p
- Publication Year :
- 2018
-
Abstract
- Abstract: Phase relations of Al<subscript>2</subscript>SiO<subscript>5</subscript> have been studied by multianvil experiments at pressures of 13–23 GPa and temperatures of 2000–2900 K. Al<subscript>2</subscript>SiO<subscript>5</subscript> kyanite was found to transform into two new high‐pressure forms of Al<subscript>2</subscript>SiO<subscript>5</subscript> (kyanite II and III) at temperatures exceeding 2300–2500 K and pressures of 14–23 GPa: The first phase transition occurs near 14 GPa, and the second occurs near 17 GPa. The new Al<subscript>2</subscript>SiO<subscript>5</subscript> phases have triclinic and monoclinic crystal symmetries with zero‐pressure densities of 3.876(2) and 3.982(1) g/cm<superscript>3</superscript>, respectively, which are significantly denser than kyanite (ρ<subscript>0</subscript> = 3.666 g/cm<superscript>3</superscript>) but less dense than the isochemical mixture of Al<subscript>2</subscript>O<subscript>3</subscript> corundum and SiO<subscript>2</subscript> stishovite (ρ<subscript>0</subscript> = 4.036 g/cm<superscript>3</superscript>). The exceptionally high stability temperatures of the new Al<subscript>2</subscript>SiO<subscript>5</subscript> phases suggest that they are unlikely to form in the present mantle but may be found in some impact craters and shocked meteorites and act as important indicators of pressure and temperature for the shock events. [ABSTRACT FROM AUTHOR]
- Subjects :
- PHASE transitions
CYANITE
SILICON
HIGH pressure (Science)
HIGH temperatures
Subjects
Details
- Language :
- English
- ISSN :
- 00948276
- Volume :
- 45
- Issue :
- 16
- Database :
- Complementary Index
- Journal :
- Geophysical Research Letters
- Publication Type :
- Academic Journal
- Accession number :
- 131976375
- Full Text :
- https://doi.org/10.1029/2018GL078960