HR: 13:40h
AN: P53A-01 INVITED     [Abstracts]
TI: H₂O under Extreme Conditions
AU: * Hemley, R J
EM: r.hemley@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015 United States
AU: Lin, J
EM: j.lin@gl.ciw.edu
AF: Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550 United States
AU: Gregoryanz, E
EM: e.gregoryanz@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015 United States
AU: Goncharov, A
EM: a.goncharov@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015 United States
AU: Struzhkin, V
EM: v.struzhkin@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015 United States
AU: Somayazulu, M
EM: zulu@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015 United States
AU: Mao, H
EM: h.mao@gl.ciw.edu
AF: Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road, NW, Washington, DC 20015 United States
AU: Yoshimura, Y
EM: muki@nda.ac.jp
AF: Department of Chemistry, National Defense Academy, Yokosuka, Kanagawa, 239-8686 Japan
AB: Water consists of the first and third most abundant elements in the solar system and is ubiquitous in the cosmos. However, knowledge of its behavior over the broad range of P-T conditions relevant to the entire solar system is only just now becoming available. Advances in high P-T techniques, including spectroscopies, x-ray and neutron scattering, and a variety of computational theory are providing an important baseline for planetary models. This new information includes stable and metastable transitions, phase relations, equations of state, vibrational dynamics, and structures of solid and fluid phases over a broad range of conditions. The P-T phase diagram of H₂O has been the subject of a number of recent studies. Measurements of the melting curve using spectroscopic and x-ray diffraction reveal a steep rise in the melting temperature of above the triple point near 35 GPa and 1040 K. The melting line may intersect the isentropes of Neptune and Uranus, giving rise the stratified layers of solid ice at depth within these planets. The high melting temperature of H₂O may also ihave important implications for the Earth's lower mantle above 60 GPa. The presence of any free H₂O would result in changes in physical properties, such as viscosity, in the mid lower mantle . The low P-T properties of H₂O are particularly important for understanding processes on planetary bodies such as satellites of the outer solar system. Studies below 10 GPa and at variable temperatures (to 10 K) reveal metastable transitions, including both crystalline and high-density amorphous forms, relevant to planetary impacts. There are important effects of solutes on the low P-T properties of these metastable phases. Salt solutions stabilize the amorphous phases and the formation of low-temperature clathrates with gas molecules can form, providing a mechanism for incorporation of gases in growing planetary bodies.
DE: 3616 Hydrothermal systems (0450, 1034, 3017, 4832, 8135, 8424)
DE: 3672 Planetary mineralogy and petrology (5410)
DE: 3924 High-pressure behavior
DE: 3934 Optical, infrared, and Raman spectroscopy
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
SC: Planetary Sciences [P]
MN: Fall Meeting 2005