Thermal diffusivity and thermal conductivity of granitoids at 283–988 K and 0.3–1.5 GPa

Abstract

The thermal diffusivity and thermal conductivity of four natural granitoid samples were simultaneously measured at high pressures (up to 1.5 GPa) and temperatures (up to 988 K) in a multi-anvil apparatus using the transient plane–source method. Experimental results show that thermal diffusivity and thermal conductivity decreased with increasing temperature (<600 K) and remain constant or slightly increase at a temperature range from 700 to 988 K. Thermal conductivity decreases 23–46% between room temperature and 988 K, suggesting typical manifestations of phonon conductivity. At higher temperatures, an additional radiative contribution is observed in four natural granitoids. Pressure exerts a weak but clear and positive influence on thermal transport properties. The thermal diffusivity and thermal conductivity of all granitoid samples exhibit a positive linear dependence on quartz content, whereas a negative linear dependence on plagioclase content appears. Combining these results with the measured densities, thermal diffusivity, and thermal conductivity, and specific heat capacities of end-member minerals, the thermal diffusivity and thermal conductivity and bulk heat capacities for granitoids predicted from several mixing models are found to be consistent with the present experimental data. Furthermore, by combining the measured thermal properties and surface heat flows, calculated geotherms suggest that the presence of partial melting induced by muscovite or biotite dehydration likely occurs in the upper-middle crust of southern Tibet. This finding provides new insights into the origin of low-velocity and high-conductivity anomaly zones revealed by geophysical observations in this region.

Thermal Conductivity and Thermal Diffusivity of Talc at High Temperature and Pressure With Implications for the Thermal Structure of Subduction Zones

“…Therefore, at a given pressure, the dependence of the thermal conductivity and thermal diffusivity on the of 373, 573, 773, 1,073, and 1,373 K. GUO ET AL. 10.1029/2021JB023425 7 of 14 temperature can be expressed using the following empirical equations (Fu et al, 2019;Hofmeister et al, 2014;Ray et al, 2006):…”

Effect of Water on the Thermal Properties of Olivine With Implications for Lunar Internal Temperature

“…Transient plane-source method was adopted (Dzhavadov, 1975;Osako et al, 2004). The cell assembly is shown in Figure 3, which is essentially the same as Fu et al (2019). Three thin disks with nearly identical double-polished specimens were piled face to face in the center of sample chamber.…”

Effect of Structural Ordering, Temperature, and Pressure on Processes of Heat Transfer in Minerals and Alloys

“…The results from measurements presented in Table 1 and our analysis of the available literature data [11][12][13][14][15][16] show that under pressure, the efficient thermal conductivity of rocks and alloys with complex, blocky, and disordered (amorphous and crystalline) structure grows rapidly up to a pressure of 100 MPa, after which there is weak growth. According to Table 1 and the literature data [12,17], pressure also affects patterns of the temperature dependence of efficient thermal conductivity and exponent n in Eq.…”

“…Numerous data of our own [8][9][10] and from the literature [12][13][14][15][16][17][18][19][20][21] show that n = −1 for ordered minerals and alloys; n = −0.5 for partially ordered minerals and alloys; n = 0 when the degree of disorder in minerals and alloys is ε = 36.4% [18]; and n = 0.5 for when the structure of minerals and rocks is amorphous (with no long-range translational bonds between atoms). The temperature dependence of the efficient thermal conductivity of minerals and rocks thus lies within the narrow domain of to and provides an estimate of their degree of disorder ε.…”