The influence of long-wavelength tilting and climatic change on sediment accumulation

摘要: The elevation of continental interiors over time is demonstrably variable. A major part change in within the interior likely driven by density changes upper mantle and global convection. For example, upper-mantle flow has been invoked as cause Neogene uplift Rocky Mountains Colorado Plateau, warping tilting sediment transport slopes that link to widespread deposition gravel units Great Plains. These geomorphic sedimentologic features, however, can also be generated an increase runoff, since erosion will promote due isostatic compensation loading lithosphere sediment. To explore consequences topography climate, we use a general length-dependent diffusive law model both includes concentrative effects river systems. simplicity approach means collapse one dimension couple with plate flexure. We find for landscape gently tilted (slope order 10 –3 ), runoff minor effect on gradient, associated flexural response maintain at similar elevation. However, there significant depositional style when degree tilt altered by, local density. An buoyancy mantle, which increases slopes, leads transient reduction grain sizes deposited fixed location. This behavior temporary retreat zone into catchment accommodation space relative supply. opposite effect, older deposits are eroded, erosion-deposition transition rapidly moves down system. There convincing evidence formation thin laterally extensive conglomeratic Plains was reduced rate subsidence. Based results our model, suggest generally consequence slope, dynamic support regions high reduced.