Grüneisen parameter of quartz, quartzite, and fluorite at high pressures

Abstract

Temperature changes caused by small rapid pressure changes have been measured for quartzite, single‐crystal quartz, and fluorite to 36 kbar. The Grüneisen parameter was then calculated from the adiabatic pressure derivative of temperature (∂T/∂P)s by use of the thermodynamic relationship γ = Ks/T (∂T/∂P)s where Ks is the adiabatic bulk modulus. The measurements were carried out in a piston cylinder apparatus using alcohol as a pressure transmitter. Parameter γ for quartz and quartzite slightly decreases with pressure, whereas we note a large decrease in γ for fluorite with pressure. We find values for q = −(∂ ℓn γ/∂ ln V)T of 2.0, 1.7, and 4.6 for quartz, quartzite, and fluorite, respectively.

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

“…Experimental values of n = -0 In (OT/OP)s/O In p.theFigures 1, 2, and 3, respectively. The results for quartz at room temperature agree within 1% with previous measurements using hydrostatic fluid cells[Boehler et al, 1979]. Below the low quartz-high quartz transformation at 800 K, the data can be extrapolated to a 1-atm value calculated from (2).…”

Temperature dependence of the first pressure derivative of the isothermal bulk modulus for solid materials at zero pressure: Application to MgO

“… o Calculated on the experimental adiabatic compression data of Boehler et al [1979] and Murnaghan equation of state with K 300K,0 = 82.0 GPa and K ′ 300K,0 = 4.83 [ Speziale and Duffy , 2002]. …”

“…k Calculated on the experimental adiabatic compression data of Ramakrishnan et al [1979] and Murnaghan equation of state with K 300K,0 = 29.69 GPa and K 0 300K,0 = 6.74 [Vaidya and Kennedy, 1970]. l Calculated on the experimental adiabatic compression data of Boehler et al [1979] and Murnaghan equation of state with K 300K,0 = 36.4 GPa and K 0 300K,0 = 6.3 [Knittle, 1995]. m K T and @K T /@T, McSkimin et al [1965]; a, Fei [1995].…”

“…Meanwhile, the m T values tabulated by Chopelas and Boehler [1992] show that although m T is independent of pressure, it is moderately dependent on temperature. As a supplement to the work of Chopelas and Boehler [1992], we reexamined the adiabatic compression results of Bi (I) [ Ramakrishnan et al , 1979], α‐SiO 2 , and CaF 2 [ Boehler et al , 1979] and found the same invariance of m T with pressure for these materials. The m T values for Bi (I), α‐SiO 2 , and CaF 2 , which were not tabulated by Chopelas and Boehler, are 8.4, 8.3, and 9.5, respectively.…”

An equation of state for high pressure-temperature liquids (RTpress) with application to MgSiO 3 melt

“…where the Grüneisen parameter, γ, can be estimated indirectly from measurements of specific heat capacity, C V or C P , density ρ, thermal expansion α, and bulk modulus, K T or K S ; (see e.g., Boehler and Kennedy, 1977;Boehler et al, 1979;Boehler and Ramakrishnan, 1980). Understanding the behavior of the Grüneisen parameter is critical when studying convecting systems, like magma oceans, due to its control over the thermal profile:…”