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Soil Table 2: (English) Themal Properties of Rocks at 77 deg F(1-4)
Rock Type
% Occurence
in Earth's 
Crust*
k - All**
Thermal 
Conductivity
k - 80%***
Thermal 
Conductivity
c p
Specific Heat

Density

Thermal
Diffusivity
Dense Rock
--
2.00
--
0.20
200
1.20
Average Rock
--
1.40
--
0.20
175
0.96
Dense Concrete
--
1.00
--
0.20
150
0.79
Heavy Soil, Saturated
--
1.40
--
0.20
200
0.84
Solid masonry
--
0.75
--
0.21
143
0.60
Heavy Soil, Damp
--
0.75
--
0.23
131
0.60
Heavy Soil, Dry
--
0.50
--
0.20
125
0.48
Light Soil, Damp
--
0.50
--
0.25
100
0.48
Light Soil, Dry
--
0.20
--
0.20
90
0.26
Igneous Rocks
Granite 
(10% Quartz)
10.4
1.1-3.0
1.3-1.9
0.21
165
0.9-1.3
Granite 
(25% Quartz)
10.4
1.1-3.0
1.5-2.1
0.21
165
1.0-1.4
Amphibolite
42.8
1.1-2.7
1.5-2.2
 
175-195
 
Andesite
42.8
0.8-2.8
0.9-1.4
0.12
160
1.1-1.7
Basalt
42.8
1.2-1.4
 
0.17-0.21
180
0.7-0.9
Gabbro
(US Cen. Plains)
42.8
0.9-1.6
 
0.18
185
0.65-1.15
Gabbro 
(US Rocky Mtns)
42.8
1.2-2.1
 
0.18
185
0.85-1.5
Diorites
11.2
1.2-1.9
1.2-1.7
0.22
180
0.7-1.0
Grandiorites
11.2
1.2-2.0
 
0.21
170
0.8-1.3
Seditmentary Rocks
Claystone  
1.1-1.7
       
Dolomite  
0.9-3.6
1.6-3.6
0.21
170-175
1.1-2.3
Limestone  
0.8-3.6
1.4-2.2
0.22
150-175
1.0-1.4
Rock Salt  
3.7
 
0.20
130-135
 
Sandstone
1.7
1.2-2.0
 
0.24
160-170
0.7-1.2
Siltstone   0.8-1.4        
Wet Shale
(25% Quartz)
4.2
0.6-2.3
1.0-1.8
0.21
130-165
0.9-1.2
Wet Shale
(No Quartz)
4.2
0.6-2.3
0.6-0.9
0.21
130-165
0.5-0.6
Dry Shale 
(25% Quartz)
4.2
0.6-2.3
0.8-1.4
0.21
130-165
0.7-1.0
Dry Shale 
(No Quartz)
4.2
0.6-2.3
0.5-0.8
0.21
130-165
0.45-0.55
Metamorphic Rocks
Gneiss
21.4
1.0-3.3
1.3-2.0
0.22
160-175
0.9-1.2
Marble
0.9
1.2-3.2
1.2-1.9
0.22
170
0.8-1.2
Quartzite  
3.0-4.0
 
0.20
160
2.2-3.0
Schist
5.1
1.2-2.6
1.4-2.2
 
170-200
 
Slate  
0.9-1.5
 
0.22
170-175
0.6-0.9
    *     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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