A model of thermal conductivity for planetary soils: 2. Theory for cemented soils

S. Piqueux, Philip Christensen

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

A numerical model of heat conduction through particulate media made of spherical grains cemented by various bonding agents is presented. The pore-filling gas conductivity, volume fraction, and thermal conductivity of the cementing phase are tunable parameters. Cement fractions <0.001-0.01% in volume have small effects on the soil bulk thermal conductivity. A significant conductivity increase (factor 3-8) is observed for bond fractions of 0.01 to 1% in volume. In the 1 to 15% bond fraction domain, the conductivity increases continuously but less intensely (25-100% conductivity increase compared to a 1% bond system). Beyond 15% of cements, the conductivity increases vigorously and the bulk conductivity rapidly approaches that of bedrock. The composition of the cements (i.e. conductivity) has little influence on the bulk thermal inertia of the soil, especially if the volume of bond <10%. These results indicate that temperature measurements are sufficient to detect cemented soils and quantify the amount of cementing phase, but the mineralogical nature of the bonds and the typical grain size are unlikely to be determined from orbit. On Mars, a widespread surface unit characterized by a medium albedo (0.19-0.26) and medium/high thermal inertia (200-600 J s-0.5 m-2 K -1) has long been hypothesized to be associated with a duricrust. The fraction of cement required to fit the thermal data is less than ∼1-5% by volume. This small amount of material is consistent with orbital observations, confirming that soil cementation is an important factor controlling the thermal inertia of the Martian surface.

Original languageEnglish (US)
Article numberE09006
JournalJournal of Geophysical Research E: Planets
Volume114
Issue number9
DOIs
StatePublished - Sep 2009

Fingerprint

thermal conductivity
Thermal conductivity
soils
Cements
conductivity
Soils
cements
cement
inertia
soil
Cementing (shafts)
Heat conduction
Temperature measurement
Numerical models
Volume fraction
Orbits
duricrust
Gases
cementation
bedrock

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

A model of thermal conductivity for planetary soils : 2. Theory for cemented soils. / Piqueux, S.; Christensen, Philip.

In: Journal of Geophysical Research E: Planets, Vol. 114, No. 9, E09006, 09.2009.

Research output: Contribution to journalArticle

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