Terrestrial Heat FlowPatrick Loury and Alex Turner

Map of preferred global heat flux (mW m-2)Davies and Davies, 2010

Heat Loss from the Oceans

Pollack et al., 1993

Stein et al., 1994

Calculated Heat Loss from Oceanic Crust• Radius of the Earth =

6,378,100 m • Surface Area = 4= 4 (3.14) (6,378,100 m²) =

5.112E14 m²

• Oceanic Crust accounts for ~60% of the Earth’s surface

(5.112E14 m²)(.6) = 3.067E14 m²

• Mean heat flow from oceanic terrains (as calculated from Pollack at al., 1993) =

101 ± 2.2 mW m-2

• Total Heat loss contribution from oceanic crust: (3.067E14 m²) x (101 ± 2.2 mW m-2) = 3.098E16 mW = ~31 TW

Heat Loss from the ContinentsControlling Factors:• Surface area of the material• Age of the last thermo-tectonic

event• Chemical composition

Heat flow measurements*• High: Quaternary units (mean: 82.0

mW m-2) • Low: Cambrian Units (mean: 50.5

mW m-2) • Average Effective Heat Flow for

Continental Crust: 66.3 mW m-2

*(Davies and Davies, 2010)

Calculated Heat Loss from Continental Crust:• Assuming continental crust accounts for ~40% of Earth’s total surface Area:

Continental Heat Loss = (66.3 mW m-2)(0.4 x (5.112 x 1014m)) = 13.5 TW

Global Heat LossEstimates of Global Heat Loss• Davies and Davies (2010): 46.7 ± 2.0 TW• Pollack, et al. (1993): 44.2 TW• This model: 44.5 TW

• Oceanic Contribution: ~70%• Continental Contribution: ~30%

Potential Error Sources:• Limited available areas for heat flow

measurements • Calculation of effective heat flow values• Areas of abnormally high or low heat flow• Surface Area Assumptions:

• CC/OC proportion• Spherical earth