Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Adiabats of quartz, coesite, olivine, and magnesium oxide to 50 kbar and 1000 K, and the adiabatic gradient in the earth's mantle

Journal Article · · J. Geophys. Res.; (United States)

The adiabats of olivine, magnesium oxide, and quartz were measured up to 50 kbar and 1000 K. An end-loaded piston-cylinder apparatus with an in situ pressure gauge and a very fine thermocouple was used to measure (partialT/partialP)/sub s/, during adiabatic compression. A power law between (partialT/partialP)/sub s/ and compression yields values of the power n = -partial ln(partialT/partialP)/sub s//partial ln rho that agree with previous results from salts, metals, and fluids. Assuming constant values for n, the adiabatic gradient for an olivine upper mantle and a magnesium oxide lower mantle was calculated. The results agree well with some previous theoretical estimates. The volume dependence of the Grueneisen parameter ..gamma.. was calculated from the thermodynamic equation partialln ..gamma../partial ln rho = partialB/partialP-n, where B is the isothermal bulk modulus, ..gamma.. is found to a good approximation to be proportional to volume.

Research Organization:
Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90024
OSTI ID:
6396304
Journal Information:
J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 87:B7; ISSN JGREA
Country of Publication:
United States
Language:
English