Theoretical and Experimental Modeling of Geodynamiс Processes in the Slopes of Uplifts

Abstract

The flow structure created in a viscous medium at a constant angle of inclination of the free surface of an slope of the uplift is analyzed. The velocity field in a high-viscosity slope of the uplift under conditions of a horizontal pressure gradient is determined. This pressure gradient occurs when the slope height decreases with distance from the main ridge. Under a constant dynamic viscosity of the slope of the uplift, the flow velocity in the latter decreases with a distance from the axis of the main ridge. In this case, the slope of the uplift is under conditions of compressive stresses, a consequence of which is development of thrusts and compression folds. Tensile stresses in the slope of the uplift may exist with an increase in the flow velocity in the layer with distance from the axis of the main ridge. The flow velocity increases with decreasing viscosity of the layer with distance from the main ridge. The viscosity distribution at the base of the slope of the uplift with distance from the axis of the main ridge is determined using the tensile condition in the slope of the uplift. Expressions are presented for the forces causing formation of a rupture between blocks of the slope of the uplift. The magnitudes of these forces are estimated. A relation representing the condition for the formation of a disruption between the blocks is obtained. The formation of ruptures is governed by the change in viscosity along the slope of the uplift and the change in the flow velocity in it. When a rupture between the slope of the uplift forms, free vertical boundaries of the blocks appear. The motion of a high-viscosity liquid during the formation of a free vertical boundary of the block has been studied experimentally when the liquid flows from a rectangular vessel. The experiments have revealed two outflow regimes: (i) a regime of constant thickness of the liquid layer; (ii) a regime of decreasing layer thickness. Based on experimental modeling, the time of the first period after formation of the slope rupture and formation of the free volume between blocks is estimated. During this period the height of the layer (slope) is practically constant and the layer length increases. The filling of the free volume between blocks with high-viscosity slope material is considered. As the modeling shows, the filling rate of the free volume between the divergent blocks of the slope of the uplift is much higher than the formation rate of the free volume between these blocks. The parameters of the blocks of the slope of the uplift are determined. Among these parameters are the block viscosity, slope height, flow velocity, and forces acting on the blocks. The time-varying structure of the surface of the slope of the uplift is presented. There is a qualitative correspondence between the modeling results and the profile of the slope of the uplift for the Northwestern Caucasus.