We refine conventional continental-scale geodynamic models by including
conversion of mechanical work done by deformation into heat. The
intensity of the shear heating is extracted from the Brace-Goetze
strength envelope without any additional model parameters or
assumptions. Incorporation of this, certainly present, heating rate into
a model may result in up to tenfold stress reduction, which is exceeding
the effects of variation of common parameters within their uncertainty
limits. Shear heating with lithospheric thickening at high integrated
strength solves the puzzle of the heretofore-missing heat source
recorded by metamorphism, magmatism, and heat flow in mountain building.
However, the mechanism is self-limiting as the rising temperature
reduces stress and thus the rate of heat production. Thus this is a
self-regulating mechanism maintaining a moderate integrated lithospheric
strength consistent with results of model-independent force-balanced
calculations and with surface heat flow measurements.