THE VARIATION OF THERMAL TRANSPORT-PROPERTIES IN THE EARTHS CRUST

Thermal conductivity and thermal diffusivity were determined simultane ously on collections of granites and amphibolites by means of a finite pulse length method, The measurements were performed at pressures up to 500 MPa and at temperatures up to 800 degrees C. Results of investi gations of other metamorphic rocks are also presented which were obtai ned by using the Angstrom method, From the pressure and temperature de pendence of the thermal transport parameters their variations within t he crust are calculated, It was found that the thermal behaviour is do minated by the influence of the temperature, In the upper crust we hav e a strong decrease of the thermal diffusivity and a smaller decrease of the conductivity. The effect of pressure becomes increasingly impor tant in the lower crust, Therefore, there is a flat minimum of the the rmal transport parameters near the Moho, The importance of different m echanisms influencing the rock behaviour is discussed.