| NB: Report due next wednesday. Exercise 1 to 4 into an individual report, exercise 5 (Ellipsis experiment) group of 2. | |||||||||
| The continental geotherm and surface heat flow... | You can download a PDF version of this Pract: | ||||||||
| In this practical we explore the continental geotherm, how it is derived and we can used its 1D equation to derive a simple relationship between the surface heat and other thermal parameters. | |||||||||
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| Exercise 1: The steady stade geotherm derives from the 1D conduction-advection heat transfert equation (see Slide 05) and knowledge of two boundary conditions. In Slide 04 we have seen that with T=T0 at z=0, and with a surface heat flow Q0 at z=0 the crustal geotherm is: | |||||||||
| Determine the crustal geotherm for the following boundary conditions: first boundary condition: T=T0 at z=0; second boundary condition: the heat flow entering the crust is Qm at z=zc. Where zc is the thickness of the continental crust.
Exercise 2: Demonstrate that the surface heat flow Q0 is a simple function of Qm, A, and zc. Exercise 3: A continental crust is zc=35 km thick, it has a depth-independent radiogenic heat production A=0.7.10-6 W.m-3, a basal heat flow Qm= 20 10-3 W.m-2, a thermal conductivity k=2.5 W.m-1.C-1 and a temperature at the surface T0=20ºC? |
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| a/ What is the temperature at the Moho b/ What is the surface heat flow Q0? c/ Assuming that the base of the lithosphere corresponds to the isotherm 1300ºC what is thickness of the lithosphere? |
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