Stability and structure of MgSiO3 perovskite to 2300-kilometer depth in Earth's mantle

Citation
Sh. Shim et al., Stability and structure of MgSiO3 perovskite to 2300-kilometer depth in Earth's mantle, SCIENCE, 293(5539), 2001, pp. 2437-2440
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Multidisciplinary,Multidisciplinary,Multidisciplinary
Journal title
SCIENCE
ISSN journal
0036-8075 → ACNP
Volume
293
Issue
5539
Year of publication
2001
Pages
2437 - 2440
Database
ISI
SICI code
0036-8075(20010928)293:5539<2437:SASOMP>2.0.ZU;2-Y
Abstract
Unexplained features have been observed seismicaliy near the middle (simila r to 1700-kilometer depth) and bottom of the Earth's tower mantle, and thes e could have important implications for the dynamics and evolution of the p lanet. (Mg,Fe)SiO3 perovskite is expected to be the dominant mineral in the deep mantle, but experimental results are discrepant regarding its stabili ty and structure. Here we report in situ x-ray diffraction observations of (Mg,Fe)SiO3 perovskite at conditions (50 to 106 gigapascals, 1600 to 2400 k elvin) close to a mantle geotherm from three different starting materials, (Mg0.9Fe0.1)SiO enstatite, MgSiO3 glass, and an MgO+SiO2 mixture. Our resul ts confirm the stability of (Mg,Fe)SiO3 perovskite to at least 2300-kitomet er depth in the mantle. However, diffraction patterns above 83 gigapascals and 1700 kelvin (1900-kilometer depth) cannot presently rule out a possible transformation from Pbnm perovskite to one of three other possible perovsk ite structures with space group P2(1)/m, Pmmn, or P4(2)/nmc.