Effect of Pressure and Temperature on the Thermal Conductivity of Rocks

Abstract

Effective thermal conductivity (ETC) of five dry rocks (sandstone, limestone, amphibolite, granulite, and pyroxenegranulite) have been measured over a temperature range from (273 to 423) K and at pressures up to 350 MPa with a steady-state parallel-plate apparatus. It is an absolute, steady-state measurement device with an operational temperature range of (273 to 1273) K and hydrostatic pressures up to 1500 MPa. The estimated uncertainty of the method is 2 %. The porosity of the samples (sandstone, limestone, amphibolite, granulite, and pyroxene-granulite) was 5 %, 5 %, 1.0 %, 1.0 %, and 1.2 %, respectively. A sharp increase of ETC was found for rocks at low pressures between (0.1 and 100) MPa along various isotherms between (273 and 423) K. At high pressures (P > 100 MPa), a weak linear dependence of the ETC with pressure was observed. The measured values of ETC of rocks were used to test and confirm of applicability of the various theoretical and semiempirical models. The effect of structure (size, shape, and distribution of the pores), porosity, and mineralogical composition on temperature and pressure dependences of the ETC of various rocks types is discussed.

Lithosphere thermal structure at the eastern margin of the Bohemian Massif: a case petrological and geophysical study of the Niedźwiedź amphibolite massif (SW Poland)

“…Moreover, they indicate that j strongly decreases from 1.5 to 2.5 mm 2 s -1 at ambient conditions to 0.5 mm 2 s -1 at midcrustal temperatures. Their results as well as the results of Abdulagatov et al (2006) suggest that the average k of the crust is *2 W m -1 K -1 .…”

“…Note that this isotherm is used often as the lithosphere-asthenosphere boundary. The same Table 2 Constants: E, B, k 0 ,U 0 , p 0 used in formulas (7) and (9) Rock no (see Table 1 After Clauser and Huenges (1995), Zoth and Hänel (1988) and Abdulagatov et al (2006) Two models of the crust are assumed (cf. Fig.…”

“…The effect of temperature and pressure on the crustal rock conductivity is included in the model. According to Abdulagatov et al (2006), a sharp increase in the conductivity is found for Depth (km) c d Fig. 9 Geotherms for the simple model of the lithosphere (see text).…”

“…Most of the results (e.g. Clauser and Huenges 1995;Seipold 1998;Tommasi et al 2001;Abdulagatov et al 2006;Katsur 2007;Whittington et al 2009) indicate that thermal conductivity and thermal diffusivity stabilize for the p-T range of upper lithospheric mantle (i.e. for: 1-4 GPa, and 700-1,500°C).…”

An Extensive Phase Space for the Potential Martian Biosphere

“…Pore space deforms at high temperatures of *400°C (Hyndman and Shearer, 1989, and references therein); hence, rocks that have experienced depths of *200 km on Mars would be expected to have no pore space (however, overburden pressure in combination with the low yield strength of rocks due to high temperature may effectively close pore space before these temperatures are reached). The closure depth of pore space for any particular rock type is poorly known; however, pore space in martian plutonic rocks would be expected to fall below 1% volume at depths greater than 40 km (less deep for basalts), which corresponds to *350 MPa (Abdulagatov et al, 2006). Appendix D provides a more detailed discussion of the dependence of pore space on depth.…”