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Figure 7.16. Models of
temperature profiles in
the Earth. (a) Solid black
line, mantle adiabat with a
thermal boundary layer at
the surface and at the
core-mantle boundary.
Dashed black line, mantle
adiabat for a thermal
boundary layer both at
the top and at the bottom
of the lower mantle. The
dashed-line adiabat
indicates that there is a
chemical and dynamic
boundary between the
upper and lower mantle,
which are assumed to be
separate systems. Grey
lines, location of
boundary layers. The
temperature at the
core-mantle boundary is
assumed to be in the
range 2900-3200 C.
(b) An estimate of
temperatures in the Earth
based on high-pressure
(over 1000 GPa) and
high-temperature (up to
6700 C) experiments on
iron and on theoretical
calculations. The shading
reflects the uncertainty in
temperatures at depth.
The 'old estimate' is
typical of temperature
profiles proposed prior to
1987. The dashed line is a
theoretical superadiabatic
gradient in the deep lower
mantle. (Based on Jeanloz
and Richter (1979),
Jeanloz (1988),
Bukowinski (1999) and da
Silva (2000).)
(a)
4000
3000
2000
1000
LOWER
MANTLE
UPPER
MANTLE
CORE
0
0
1000
2000
3000
Depth (km)
(b)
8000
6000
4000
2000
OUTER
CORE
I NNER
CORE
MANTLE
(solid)
(liquid)
(solid)
0
0
2000
4000
6000
Depth (km)
 
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