This article gives a mechanical model, in which the layers of lithosphere are assumed to be the creep materials, to study the coupling mechanism of a syn-basin-mountain system quantitatively by using the numerical s...This article gives a mechanical model, in which the layers of lithosphere are assumed to be the creep materials, to study the coupling mechanism of a syn-basin-mountain system quantitatively by using the numerical simulating method. A geological dynamic extensional mode given by some geologists is theoretically discussed and verified. The study shows that lithosphere thickening or thinning is closely related to the thermal activity, or in other words, thermal convection beneath the lithosphere. It is one of the important factors affecting the formation of the basin-mountain coupling system. As an essential condition, only the upward buoyant force and the horizontal dragging force caused by the thermal convection jointly act on the bottom of the lithosphere, the stress and strain states in rock's layers are advantageous to forming the tectonic-landforms of the basin-mountain coupling system. A study on the creep features of the lithosphere shows that the stress and strain in the rock's layers vary with time when the lasting forces act on the boundary. They increase rapidly at initial stage and decrease steadily after reaching the peak value. Phenomena of stress relaxation are significant for studying the tectonic evolution.展开更多
基金ThispaperissupportedbytheNationalNaturalScienceFoundationofChina (No .1 9972 0 64)andtheMinistryofLandandResources (No.991 0 0 5)
文摘This article gives a mechanical model, in which the layers of lithosphere are assumed to be the creep materials, to study the coupling mechanism of a syn-basin-mountain system quantitatively by using the numerical simulating method. A geological dynamic extensional mode given by some geologists is theoretically discussed and verified. The study shows that lithosphere thickening or thinning is closely related to the thermal activity, or in other words, thermal convection beneath the lithosphere. It is one of the important factors affecting the formation of the basin-mountain coupling system. As an essential condition, only the upward buoyant force and the horizontal dragging force caused by the thermal convection jointly act on the bottom of the lithosphere, the stress and strain states in rock's layers are advantageous to forming the tectonic-landforms of the basin-mountain coupling system. A study on the creep features of the lithosphere shows that the stress and strain in the rock's layers vary with time when the lasting forces act on the boundary. They increase rapidly at initial stage and decrease steadily after reaching the peak value. Phenomena of stress relaxation are significant for studying the tectonic evolution.
