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Soil Table 2: Themal Properties of Rocks at 25 deg C(1-4)
Rock Type
% Occurence
in Earth's 
Crust*
k - All**
Thermal 
Conductivity
(W/m*K)
k - 80%***
Thermal 
Conductivity
(W/m*K)
c p
Specific Heat
(J/kg*K)

Density

Thermal
Diffusivity
Dense Rock
--
3.46
--
840
3200
0.111
Average Rock
--
2.42
--
840
2800
0.089
Dense Concrete
--
1.73
--
840
2400
0.073
Heavy Soil, Saturated
--
2.42
--
840
3200
0.078
Solid masonry
--
1.3
--
880
2290
0.056
Heavy Soil, Damp
--
1.3
--
960
2100
0.056
Heavy Soil, Dry
--
0.87
--
840
2000
0.045
Light Soil, Damp
--
0.87
--
1050
1600
0.045
Light Soil, Dry
--
0.35
--
840
1440
0.024
Igneous Rocks
Granite 
(10% Quartz)
10.4
1.9-5.1
2.3-3.3
879
2640
0.084-0.12
Granite 
(25% Quartz)
2.6-3.6
0.093-0.13
Amphibolite
42.8
1.9-4.7
2.6-3.8
 
2800-3120
 
Andesite
1.4-4.8
1.6-2.4
502
2560
0.10-0.16
Basalt
2.1-2.4
 
712-879
2880
0.065-0.084
Gabbro
(US Cen. Plains)
1.6-2.8
 
753
2960
0.060-0.107
Gabbro 
(US Rocky Mtns)
2.1-3.6
 
0.079-0.14
Diorites
11.2
2.1-3.3
2.1-2.9
920
2880
0.065-0.093
Grandiorites
2.1-3.5
 
879
2720
0.074-0.12
Seditmentary Rocks
Claystone  
1.9-2.9
       
Dolomite  
1.6-6.2
2.8-6.2
879
2720-2800
0.10-0.21
Limestone  
1.4-6.2
2.4-3.8
920
2400-2800
0.093-0.13
Rock Salt  
6.4
 
837
2080-2160
 
Sandstone
1.7
2.1-3.5
 
1005
2560-2720
0.065-0.11
Siltstone   1.4-2.4        
Wet Shale
(25% Quartz)
4.2
1.0-4.0
1.7-3.1
879
2080-2640
0.084-0.11
Wet Shale
(No Quartz)
1.0-1.6
0.047-0.056
Dry Shale 
(25% Quartz)
1.4-2.4
0.065-0.093
Dry Shale 
(No Quartz)
0.9-1.4
0.042-0.051
Metamorphic Rocks
Gneiss
21.4
1.7-5.7
2.3-3.5
920
2650-2800
0.084-0.11
Marble
0.9
2.1-5.5
2.1-3.3
920
2720
0.074-0.11
Quartzite  
5.2-6.9
 
837
2560
0.20-0.28
Schist
5.1
2.1-4.5
2.4-3.8
 
2720-3200
 
Slate  
1.6-2.6
 
920
2720-2800
0.056-0.084
    *     Percentage of sedimentary rocks is higher near the surface.
  **    "All" represents the conductivity range of all samples tested.
***   "80%" represents the mid-range for samples of rock.

1. H.S. Carslaw and J.C. Jaeger, Conduction of Heat in Solids.  Oxford: Claremore Press, 1947.
2. L.R. Ingersoll, O.J. Zobel, and A.C. Ingersoll, Heat Conduction: with Engineering and Geological Applications, 2nd ed. McGraw-Hill, New York, 1954.
3. S.P. Kavenaugh, "Simulation of Ground-Coupled Heat Pumps with an Analytical Solution," Proceedings of the ASME International Solar Energy Conference.  New York: American Society of Mechanical Engineers, 1992.
4. Closed-Loop/Ground-Source Heat Pump Systems Installation Guide.  NRECA Research Project 86-1.  Oklahoma State University.  1988

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