The earth's thermal profile: Is there a mid-mantle thermal boundary layer?
- Resource Type
- Authors
- S. Spiliopoulos; F.D. Stacey
- Source
- Journal of Geodynamics. 1:61-77
- Subject
- Convection
Boundary layer
Geophysics
Extrapolation
Inner core
Mineralogy
Density contrast
Atomic physics
Adiabatic process
Mantle (geology)
Outer core
Geology
Earth-Surface Processes
- Language
- ISSN
- 0264-3707
Shock observations on melting of iron by Brown and McQueen with the inner core boundary (ICB) density contrast estimated by Masters are used with the assumption that the light ingredient of the outer core is oxygen to calculate the boundary temperature T ICB = (5000 ± 900) K. Adiabatic extrapolation to the core-mantle boundary (CMB) gives T ICB = (3800 ± 800) K. The temperature increment across the D ″ layer is not well constrained, but is estimated to be T D ″ = (800 ± 400) K and a slightly superadiabatic extrapolation to 670 km gives T 670 + = (2300 ± 950) K. This is only about 300 K higher than the extrapolation to the same level from the upper mantle, T 670− = (1970 ± 150) K. The difference is far too small to make a viable mid-mantle boundary layer. Remaining unceertainties are too large to discount such a boundary layer with certainty, but agreement of our new temperature profile with temperatures deduced from equation of state studies on the lower mantle and core encourages the view that we are converging to a well-determined temperature profile for the Earth.