Continental lithosphere deformation is a response to its thermodynamically controlled critical crustal thickness

We study the present-day thermo-mechanical state of the Alpine Himalayan Collision Zone to understand the physics controlling the observed crustal differentiation and the underlying continental-wide geodynamics. We found that the stability of the lithosphere is regulated by a thermodynamically controlled critical crustal thickness (C_r), which is close to the average thickness of the continental crust. Regions with thickness higher than C_r, representing orogenic lithosphere, and higher than average potential energy undergo weakening and dissipate the acquired internal energy, compared to their foreland lithospheres that have crustal thickness close to C_r. A weaker orogenic lithosphere deforming in a dissipative mode to release the acquired potential energy manifests as zones of diffused rather than focused deformation. We additionally find that the energy dissipation path that the orogenic lithosphere takes to either attain C_r (cratonization) or to undergo runaway instability (rifting) is modulated by the feedback between the thermal and mechanical relaxation of the lithosphere. The internal energy stored in the crust from heat-producing elements, fastens the dissipation of the acquired potential energy.