Different scenarios influencing plate thickness
a) Hot and cold geotherms; b) corresponding effective lithospheric plate thickness as a function of frequency c) apparent plate thickness for North America for different kinds of geophysical observations/loading mechanisms. Credit: Lau, Holtzman, & Havlin, 2020, Figure 3
Source: AGU Advances

Rocks deform as elastic solids or viscous fluids depending on pressure and temperature. If viscous and elastic mechanisms act together, the frequency of loading relative to an internal resonance can determine if the rock feels elastically weak or strong. Lau, Holtzman, & Havlin [2020] recently worked to expand such classical descriptions to a frequency-dependent viscosity, taking into account a range of microphysical mechanisms. In this perspective, the authors further explore how this framework can be used to understand contrasting estimates of lithospheric plate thickness. In particular, long-term convective loading estimates associated with thinner plates can be reconciled with shorter frequency estimates of thicker plates. The new approach sets out a blueprint how to unify the representation of a range of field and laboratory constraints for the thermo-mechanical character of the lithosphere, including how plates transition from supporting mountains to squishy folding into the mantle at subduction zones.

Citation: Lau, H., Holtzman, B., & Havlin, C. [2020]. Towards a Self-consistent Characterization of Lithospheric Plates Using Full-spectrum Viscoelasticity. AGU Advances, 1, e2020AV000205. https://doi.org/10.1029/2020AV000205

—Thorsten Becker, Editor, AGU Advances