PERSPECTIVES ON LITHOSPHERE RHEOLOGY THROUGH THE INTEGRATION OF EXPERIMENTAL ROCK MECHANICS WITH GEOLOGICAL AND GEOPHYSICAL OBSERVATIONS

Decades of structural and microstructural work on deformed rocks has provided invaluable insight into the rheological properties of the crust and mantle in a wide range of tectonic environments. More recently, improvements in analytical techniques for constraining the timing and temperature of deformation provide new opportunities for using geologic observations to investigate the efficacy of applying lab-derived flow laws to geologic conditions – which often require large extrapolation in either stress or temperature. This approach is bolstered by correlation of relatively unique deformation microstructures between lab and natural samples – which can thus be used to infer that the same deformation processes are active. Through these techniques, the uncertainties in the extrapolation of the flow laws can be reduced, validating their application over a broader range of conditions where geologic data may be more limited. Looking to future, the integration of these techniques can be further leveraged to constrain transient deformation processes associated with the seismic cycle – as observed using new geodetic observations - and the evolution of stress state near the brittle-plastic transition. In this presentation, I will provide some new examples of these types of studies and provide a brief outline of newer experimental advancements that can be employed to provide improved constraints on the rheological behavior of the lithosphere.