Related Content
Search Google Scholar for:
|
|
Science 19 February 1988:
Vol. 239. no. 4842, pp. 902 - 905
DOI: 10.1126/science.239.4842.902
|
|
Articles
Spectroscopic Evidence for Pressure-Induced Coordination Changes in Silicate Glasses and Melts
QUENTIN WILLIAMS 1 and
RAYMOND JEANLOZ 1
1 Department of Geology and Geophysics, University of California, Berkeley, CA 94720.
Infrared spectra demonstrate that at pressures above 20 gigapascals and room temperature the regular tetrahedral coordination of oxygen around both silicon and aluminum ions is severely disrupted in SiO2, CaMgSi2O6, and CaAlSi2O8 composition glasses. The spectra are consistent with gradual, pressure-induced increases in the coordination numbers of silicon and aluminum. A variety of coordination environments, from sixfold to fourfold, appears to be present at pressures as high as about 40 gigapascals. This apparent change in coordination is not quenchable at room temperature: on decompression, the glasses return to tetrahedral coordination. This continuous and reversible coordination change in amorphous silicates explains the lack of observation of coordination changes in silicate glasses quenched from high pressure, the shallow melting slopes observed for mantle silicates at high pressures, and the possible presence of neutrally buoyant magmas deep within the terrestrial planets.
Submitted on November 17, 1987
Accepted on January 20, 1988
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
- Anomalous high-pressure behavior of amorphous selenium from synchrotron x-ray diffraction and microtomography.
- H. Liu, L. Wang, X. Xiao, F. De Carlo, J. Feng, H.-k. Mao, and R. J. Hemley (2008)
PNAS
105, 13229-13234
| Abstract »
| Full Text »
| PDF »
- Thermal infrared spectroscopy and modeling of experimentally shocked basalts.
- J. R. Johnson, M. I. Staid, and M. D. Kraft (2007)
American Mineralogist
92, 1148-1157
| Abstract »
| Full Text »
| PDF »
- Structure and Freezing of MgSiO3 Liquid in Earth's Lower Mantle.
- L. Stixrude and B. Karki (2005)
Science
310, 297-299
| Abstract »
| Full Text »
| PDF »
- A new dense silica polymorph: A possible link between tetrahedrally and octahedrally coordinated silica.
- S.-N. Luo, S.-N. Luo, O. Tschauner, P. D. Asimow, and T. J. Ahrens (2004)
American Mineralogist
89, 455-461
| Abstract »
| Full Text »
| PDF »
- Thermal infrared spectroscopy and modeling of experimentally shocked plagioclase feldspars.
- J. R. Johnson, J. R. Johnson, F. Horz, and M. I. Staid (2003)
American Mineralogist
88, 1575-1582
| Abstract »
| Full Text »
| PDF »
- Al Coordination Changes in High-Pressure Aluminosilicate Liquids.
- J. L. Yarger, K. H. Smith, R. A. Nieman, J. Diefenbacher, G. H. Wolf, B. T. Poe, and P. F. McMillan (1995)
Science
270, 1964-1967
| Abstract »
| PDF »
- Pressure-Induced Coordination Changes in Alkali-Germanate Melts: An in Situ Spectroscopic Investigation.
- D. L. Farber, D. L. Farber, and Q. Williams (1992)
Science
256, 1427-1430
| Abstract »
| PDF »
- A Novel Topological Compression Mechanism in a Covalent Liquid.
- Lars. Stixrude, L. Stixrude, and M. S. T. Bukowinski (1990)
Science
250, 541-543
| Abstract »
| PDF »
- Memory Glass: An Amorphous Material Formed from AlPO4.
- M. B. Kruger, M. B. Kruger, and R. Jeanloz (1990)
Science
249, 647-649
| Abstract »
| PDF »
- Ultrahigh-Pressure Melting of Lead: A Multidisciplinary Study.
- B. K. Godwal, B. K. Godwal, C. Meade, R. Jeanloz, A. Garcia, A. Y. Liu, and M. L. Cohen (1990)
Science
248, 462-465
| Abstract »
| PDF »
- Silicon Coordination and Speciation Changes in a Silicate Liquid at High Pressures.
- X. Xue, X. XUE, M. KANZAKI, R. G. TRONNES, and J. F. STEBBINS (1989)
Science
245, 962-964
| Abstract »
| PDF »
- Nuclear Magnetic Resonance Spectroscopy in the Earth Sciences: Structure and Dynamics.
- J. F. Stebbins, J. F. STEBBINS, and I. FARNAN (1989)
Science
245, 257-263
| Abstract »
| PDF »
- Effect of a Coordination Change on the Strength of Amorphous SiO2.
- C. Meade, C. MEADE, and R. JEANLOZ (1988)
Science
241, 1072-1074
| Abstract »
| PDF »
|
|
