Physical explanation of the formation and evolution of inversion zones and marginal troughs

Inversion zones are elongate structures, some tens of kilometers wide and up to hundreds of kilometers long, that have deformed in response to compression and produced topography. Inversion zones in the Alpine foreland are mainly associated with Mesozoic grabens and troughs, and although very important in the geologic picture, the conditions of their formation and evolution and their regional geologic significance are not entirely understood. The internal structure of inversion zones is variable and depends on details in the pre-inversion setting, the inversion-inducing stress held, and the sedimentary fill. However, on a larger scale, most inversion zones share certain principal observational features, which sample the physical structure and the theologic properties of the lithosphere and thereby provide an opportunity to test hypotheses of lithospheric rheology and dynamics. The quantitative model presented in this paper explains how inversion zones and the associated marginal troughs are related to Lithospheric zones of differential shortening and regional isostatic compensation of the induced topography.