Heat transfer

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Heat transfer
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Basic Idea
Heat flow
Earth
HOT
COLD
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Global heat flux
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Geothermal Map of North America
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Global heat flux
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Sea Floor Spreading

• Ship surveys sea floor age

http//terra.rice.edu/plateboundary/index.html
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Mid-ocean ridge
Older colder thicker lower
heat flux
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Cooling of lithosphere
From Stein Stein, Nature, 1992
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Error function
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Error function
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Solution to 1D diffusion equation
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Solution to 1D diffusion equation
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Solution to 1D diffusion equation
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Solution to 1D diffusion equation
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Solution to 1D diffusion equation
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Solution to 1D diffusion equation
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Cooling of the lithosphere

• From Richardson et al., GRL, 1995

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Temperature profile inside Earth
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Temperature profile inside Earth
Thermal boundary layers
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
Mantle adiabatic gradient
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
Mantle adiabatic gradient
Core adiabatic gradient
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
Mantle adiabatic gradient
Core adiabatic gradient
Melting curve for Fe ?
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
Mantle adiabatic gradient
Core adiabatic gradient
5000 - 5300 oC (mineral physics)
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
2200 - 2500 oC (at top of D)
3300 - 4000 oC (at CMB)
5000 - 5300 oC (mineral physics)
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
dT 800 - 1800 oC
5000 - 5300 oC (mineral physics)
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
Layered convection
dT 800 - 1800 oC
5000 - 5300 oC (mineral physics)
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Post-perovskite
Variation in depth of top of D depends on the
local geotherm, which determines where the phase
transition from perovskite to post-perovskite
occurs.
From Hernlund et al, nature, 2005
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Temperature profile inside Earth
1400 - 1500 oC (cooling of lithosphere)
1600 - 1800 oC (phase transition temp.
from mineral physics)
2400 oC (Pv to pPv)
3700 oC (pPv to Pv)
5000 - 5300 oC (mineral physics)
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Thermal evolution of the Earth
Present Temp. Past Temp. Future Temp. Fe
melting curve
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Thermal evolution of the Earth
Present Temp. Past Temp. Future Temp. Fe
melting curve
Future ICB
No inner core
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Degree 2 heterogeneity
Ritsema and van Heijst, 2001
Slide credit S. Rost
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CMB heat flux signature on magnetic field
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CMB heat flux signature on magnetic field
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CMB heat flux signature on magnetic field
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CMB heat flux signature on magnetic field
Blue high heat flux Red low heat flux
From Bloxham, GRL, 2002