NB: Individual practical reports are due next week and will be collected at the beginning of the practical class. Should you hand-in your report later do not forget to write the date at which the report was handed in on the front page, without this information I will have to use the date at which we collected the report. This is a report, not an answer sheet, so please give enough details so the assessor can understand your solution. Hand written reports are acceptable, but please write clearly. Non-advanced report: Exercises 1 to 3; Advanced Report: Exercises 1 to 4.
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 how it can be used to derive new knowledge regarding the surface heat flow.
Exercise 1: The steady state geotherm derives from the 1D conduction-advection heat transfer equation (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 (1):
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 depth of the base of the continental crust (we assume the top of the crust is at z=0m).

Exercise 2: Compare your result with equation (1) and demonstrate that the surface heat flow Q0 is a simple function of Qm, A, and zc. Give this function.

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?
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?