Post‐Gondwana geomorphic evolution of southwestern Africa: Implications for the controls on landscape development from observations and numerical experiments

摘要: The relationship between morphology and surficial geology is used to quantify the denudation that has occurred across southwestern Africa since fragmentation of Gondwana during Early Mesozoic. Two main points emerge. Significant denudation, order kilometers, widespread except in Kalahari region continental interior. systematically distributed so exterior catchment, draining directly Cape basin, denuded a greater depth than interior catchment inland Great Escarpment analysis also implies majority before beginning Cenozoic for both catchments. Existing models landscape development are reviewed, implications chronology incorporated into revised conceptual model. This revision primary effect rifting on subsequent evolution it generates two distinct drainage regimes. A marginal upwarp, or rift flank uplift, separates rejuvenated rivers drain subsiding from deflected but not rejuvenated. catchments evolve independently unless they integrated by breaching upwarp. If this occurs, baselevel communicated accordingly. Denudation rates generally decrease as margin evolves, reinforced exposure substrate resistant and/or change more arid climate. observations do reveal particular style smaller-scale evolution, such escarpment retreat, responsible differential region. It proposed numerical model experiments, which reflect observational insights at large scale, may identify controls if natural systems analogous. Four experiments presented roles antecedent topography, substrate, climate change, lowering investigated an initially high elevation bordered escarpment. results suggest several styles compatible with observations. Escarpments retreat regular manner, degrade destroyed, only reform divide