Flexural models of continental lithosphere based on

Summary. The most easily observed geophysical characteristic of continents is their surface topography. Topographic power in the spectral range 1000-1 00 km has been computed for North American geological provinces and is found to decrease systematically as the tectonic age of the underlying crust increases. These data have been quantitatively modelled in terms of topographic erosion and stress relaxation within the continental lithosphere through geological time spans. The lithosphere is treated as a thin (Maxwell) viscoelastic plate which deforms flexurally in response to the vertical surface loads of topography and its erosion. Effective rheological model parameters are flexural rigidity D, a measure of the lithosphere’s elastic strength, and viscous relaxation time constant r, a measure of its viscosity. Erosion is assumed to occur at a rate linearly proportional to the height of topography at any given time, the proportionality being determined by the erosion time constant u. The models are constructed in space and time frequency domains using simple linear systems theory