Elementary modeling of ridge and graben formation in a thin viscous sheet

PERAZZO, CARLOS ALBERTO; GRATTON, JULIO

Mar del Plata

Otro; Pan-American Advanced Studies Institute (PASI) on Interfacial Fluid Dynamics: From Theory to Applications; 2007

Patrocinado por NSF y DOE

Several years ago one of us (J. Gratton, J. Geophys. Res., 94, 15627-15634, 1989) deduced scaling laws for the growth of mountain belts by means of dimensional analysis, and based on simple physical hypotheses that involve a viscous flow in a thin layer, originated by the shortening of the Earth´s crust. With the purpose to achieve a deeper understanding of these (and related) scalings we are investigating a simple model consisting of two initially uniform layers on plane horizontal substrates, that for t > 0 are pushed together (or apart) by the converging (or diverging) motion of the substrates, thus producing a ridge (or a graben). We study numerically the evolution of the flow and show that various selfsimilar regimes are achieved in different space-time domains. These selfsimilar regimes and their corresponding scaling laws can be derived analytically, including as a special case the Gratton´s scalings for mountain belts.