Rheological properties of paraffin as an analogue material for viscous crustal deformation

The rheological stratification induced by temperature variations within the crust requires analogue materials with temperature-sensitive viscosity to properly simulate the change of mechanical properties with depth. Rheological calibration experiments on commercial paraffin wax with melting point of 53±1°C show that this material is a nonlinear fluid (1.6≤n≤2.1) for homologous temperatures T/Tm<0.70, and an approximately Newtonian fluid (1.0≤n≤1.3) for T/Tm≥0.70. The decrease in the stress exponent n is probably associated with the α–β phase transition of paraffin. Effective viscosity values are strongly temperature dependent, varying by nine orders of magnitude from 1010 to 10 Pa s in the temperature range between 30 and 52°C. The rheological properties of paraffin make this material useful for modelling crustal rheology and tectonic processes, when linear dimensions and time scale down by a factor of 106 and 1011, respectively.