creation, the extra heat loss at the swells of ~3 TW raises
the nonconductive heat loss to 27.5 TW. This is approximately 85 % of the heat loss through the oceans. On the
continents, they estimate that about half of the surface heat
flow is due to radioactive decay in the upper continental
lithosphere. This leaves a conductive flow from the upper
mantle under the continents of ~6 TW, with much of this
coming from sedimentary basins and shelves as a result
of stretching of the continental crust (Jaupart et al.,
2007). Thus, almost all the surface heat flow of the Earth,
except that due to radioactivity on the continents, has as its
origin convection in the upper mantle. The heat flow from
the upper mantle through the cratons and platforms is very
low, and these areas act like an isotherm (Jaupart et al.,
2007). Thus, the heat loss from the upper mantle shows
a huge difference between that occurring beneath the
oldest continental lithosphere and that created by plate
creation at the mid-ocean ridges. This must have a major
effect on convection in the upper mantle.
Conclusions
Many fundamental advances in our understanding of the
Earth have come from the study of marine heat flow:
1. The early heat flow values were the same as, if not
higher than, the values on continents. Because of the
low radioactivity, they implied an additional source of
heat to that given by radioactivity to explain them.
2. High values observed at the crest of mid-ocean ridges
were a key observation in the development of the theory of seafloor spreading by Hess (1962).
3. Attempts to understand the high scatter in heat
flow measurements near the crest of the mid-ocean
ridges led Lister (1972) to propose widespread
hydrothermal circulation at the crest of mid-ocean
ridges.
4. There is general agreement that thermal models requiring input of heat from below best match the relations
between the heat flow and subsidence with age.
5. Removing the effect of dynamic topography in determining the relation between depth ages allows the construction of two self-consistent models that match both
the heat flow and subsidence on old ocean floor without requiring significant radioactivity in the oceanic
crust.
6. A remarkable discovery associated with plate tectonics
is that one simple thermal model can explain the general dependence of both marine heat flow and bathymetry on age.
7. Creation of oceanic plate is the major way in which the
Earth loses heat. From a global loss of 45–47 TW, three
quarters comes through the oceans with one fifth
occurring by the advection of seawater at the crest of
the mid-ocean ridges. Creation of oceanic plate
accounts for ~60 % of the heat loss of the Earth.
8. There is a large difference between the heat loss from
plate creation and that occurring under the oldest
continents.
Acknowledgments
We thank Paul Morgan for a helpful review.
Bibliography
Birch, F., 1954. The present state of geothermal investigations. Geophysics, 19, 645–659.
Bullard, E. C., 1939. Heat flow in South Africa. Proceedings of the
Royal Society of London Series A, 173, 474–502.
Bullard, E. C., 1945. Thermal history of the earth. Nature, 156, 35.
Bullard, E. C., 1952. Heat flow through the floor of the eastern
North Pacific Ocean. Nature, 170, 200.
Bullard, E. C., 1954. The flow of heat through the floor of the Atlantic Ocean. Proceedings of the Royal Society of London Series A,
222, 408–429.
Bullard, E. C., Maxwell, A. E., and Revelle, R., 1956. Heat flow
through the deep sea floor. Advances in Geophysics, 3, 153–181.
Carlson, R. L., and Johnson, H. P., 1994. On modeling the thermal
evolution of the oceanic upper mantle: an assessment of the
cooling plate model. Journal of Geophysical Research, 99,
3201–3214.
Chapman, D., and Pollack, H., 1980. Global heat flow: spherical
harmonic representation (abstract). Eos, Transactions American
Geophysical Union, 61, 383.
Chapman, D., and Pollack, H., 1987. Global heat flow: spherical
harmonic representation. In 19th General Assembly of the
IUGG, Abstracts Volume, 1, Vancouver, Canada, p. 50.
Chapman, D., and Pollock, H., 1975. Global heat flow: a new look.
Earth and Planetary Science Letters, 28, 23–32.
Chapman, D., and Rybach, L., 1985. Heat flow anomalies and their
interpretation. Journal of Geodynamics, 4, 3–37.
Crosby, A., and McKenzie, D., 2009. An analysis of young ocean
depth, gravity and global residual topography. Geophysical
Journal International, 178, 1198–1219.
Crosby, A., McKenzie, D., and Sclater, J., 2006. The relations
between depth, age and gravity in the oceans. Geophysical Journal International, 166, 553–573.
Crough, S., 1975. Thermal model of oceanic lithosphere. Nature,
256, 388–390.
Davies, G., 1980. Review of oceanic and global heat flow estimates.
Reviews of Geophysics, 18, 718–722.
Davies, J., and Davies, D., 2010. Earth’s surface heat flux. Solid
Earth, 1(1), 5–24.
Davies, J., 2013. Global map of solid earth surface heat flow. Geochemistry, Geophysics, Geosystems, 14, 4608–4622.
Davis, E., and Becker, K., 2004. Observations of temperature and
pressure: constraints on oceanic crustal hydrologic state, properties and flow. In Davis, E., and Elderfield, H. (eds.), Hydrogeology of the Oceanic Lithosphere. Cambridge: Cambridge
University Press, pp. 225–227.
Davis, E. E., Wang, K., Becker, K., Thomson, R. E. and Yashayaev,
I., 2003. Deep-ocean temperature variations and implications for
errors in seafloor heat flow determinations. Journal of Geophysical Research 108(B1), 2034, doi:10.1029/2001JB001695.
Davis, E., and Elderfield, H., 2004. Hydrology of the Oceanic Lithosphere. Cambridge: Cambridge University Press.
Davis, E., and Lister, C., 1974. Fundamentals of ridge crest topography. Earth and Planetary Science Letters, 21, 405–413.
458
MARINE HEAT FLOW
the nonconductive heat loss to 27.5 TW. This is approximately 85 % of the heat loss through the oceans. On the
continents, they estimate that about half of the surface heat
flow is due to radioactive decay in the upper continental
lithosphere. This leaves a conductive flow from the upper
mantle under the continents of ~6 TW, with much of this
coming from sedimentary basins and shelves as a result
of stretching of the continental crust (Jaupart et al.,
2007). Thus, almost all the surface heat flow of the Earth,
except that due to radioactivity on the continents, has as its
origin convection in the upper mantle. The heat flow from
the upper mantle through the cratons and platforms is very
low, and these areas act like an isotherm (Jaupart et al.,
2007). Thus, the heat loss from the upper mantle shows
a huge difference between that occurring beneath the
oldest continental lithosphere and that created by plate
creation at the mid-ocean ridges. This must have a major
effect on convection in the upper mantle.
Conclusions
Many fundamental advances in our understanding of the
Earth have come from the study of marine heat flow:
1. The early heat flow values were the same as, if not
higher than, the values on continents. Because of the
low radioactivity, they implied an additional source of
heat to that given by radioactivity to explain them.
2. High values observed at the crest of mid-ocean ridges
were a key observation in the development of the theory of seafloor spreading by Hess (1962).
3. Attempts to understand the high scatter in heat
flow measurements near the crest of the mid-ocean
ridges led Lister (1972) to propose widespread
hydrothermal circulation at the crest of mid-ocean
ridges.
4. There is general agreement that thermal models requiring input of heat from below best match the relations
between the heat flow and subsidence with age.
5. Removing the effect of dynamic topography in determining the relation between depth ages allows the construction of two self-consistent models that match both
the heat flow and subsidence on old ocean floor without requiring significant radioactivity in the oceanic
crust.
6. A remarkable discovery associated with plate tectonics
is that one simple thermal model can explain the general dependence of both marine heat flow and bathymetry on age.
7. Creation of oceanic plate is the major way in which the
Earth loses heat. From a global loss of 45–47 TW, three
quarters comes through the oceans with one fifth
occurring by the advection of seawater at the crest of
the mid-ocean ridges. Creation of oceanic plate
accounts for ~60 % of the heat loss of the Earth.
8. There is a large difference between the heat loss from
plate creation and that occurring under the oldest
continents.
Acknowledgments
We thank Paul Morgan for a helpful review.
Bibliography
Birch, F., 1954. The present state of geothermal investigations. Geophysics, 19, 645–659.
Bullard, E. C., 1939. Heat flow in South Africa. Proceedings of the
Royal Society of London Series A, 173, 474–502.
Bullard, E. C., 1945. Thermal history of the earth. Nature, 156, 35.
Bullard, E. C., 1952. Heat flow through the floor of the eastern
North Pacific Ocean. Nature, 170, 200.
Bullard, E. C., 1954. The flow of heat through the floor of the Atlantic Ocean. Proceedings of the Royal Society of London Series A,
222, 408–429.
Bullard, E. C., Maxwell, A. E., and Revelle, R., 1956. Heat flow
through the deep sea floor. Advances in Geophysics, 3, 153–181.
Carlson, R. L., and Johnson, H. P., 1994. On modeling the thermal
evolution of the oceanic upper mantle: an assessment of the
cooling plate model. Journal of Geophysical Research, 99,
3201–3214.
Chapman, D., and Pollack, H., 1980. Global heat flow: spherical
harmonic representation (abstract). Eos, Transactions American
Geophysical Union, 61, 383.
Chapman, D., and Pollack, H., 1987. Global heat flow: spherical
harmonic representation. In 19th General Assembly of the
IUGG, Abstracts Volume, 1, Vancouver, Canada, p. 50.
Chapman, D., and Pollock, H., 1975. Global heat flow: a new look.
Earth and Planetary Science Letters, 28, 23–32.
Chapman, D., and Rybach, L., 1985. Heat flow anomalies and their
interpretation. Journal of Geodynamics, 4, 3–37.
Crosby, A., and McKenzie, D., 2009. An analysis of young ocean
depth, gravity and global residual topography. Geophysical
Journal International, 178, 1198–1219.
Crosby, A., McKenzie, D., and Sclater, J., 2006. The relations
between depth, age and gravity in the oceans. Geophysical Journal International, 166, 553–573.
Crough, S., 1975. Thermal model of oceanic lithosphere. Nature,
256, 388–390.
Davies, G., 1980. Review of oceanic and global heat flow estimates.
Reviews of Geophysics, 18, 718–722.
Davies, J., and Davies, D., 2010. Earth’s surface heat flux. Solid
Earth, 1(1), 5–24.
Davies, J., 2013. Global map of solid earth surface heat flow. Geochemistry, Geophysics, Geosystems, 14, 4608–4622.
Davis, E., and Becker, K., 2004. Observations of temperature and
pressure: constraints on oceanic crustal hydrologic state, properties and flow. In Davis, E., and Elderfield, H. (eds.), Hydrogeology of the Oceanic Lithosphere. Cambridge: Cambridge
University Press, pp. 225–227.
Davis, E. E., Wang, K., Becker, K., Thomson, R. E. and Yashayaev,
I., 2003. Deep-ocean temperature variations and implications for
errors in seafloor heat flow determinations. Journal of Geophysical Research 108(B1), 2034, doi:10.1029/2001JB001695.
Davis, E., and Elderfield, H., 2004. Hydrology of the Oceanic Lithosphere. Cambridge: Cambridge University Press.
Davis, E., and Lister, C., 1974. Fundamentals of ridge crest topography. Earth and Planetary Science Letters, 21, 405–413.
458
MARINE HEAT FLOW