Evolução geomorfológica do Distrito Federal

Abstract

This work constitutes a synthesis on the physical aspects of Federal District and a proposal of geomomorphologic evolution is presented, with the following stage: formation of double surface (After-Gondwana Surface, Medium to Superior Cretaceous) - differential physical denudation processes in arid climate associates to the regional uplift; complex lateritic regolit generation (South American surface, Paleocene to Inferior Miocene) - Weathering chemical processes in humid and hot condition. Differentiation of complex lateritic regolit below the initial double surface; Lateritic regolit denudation (Inferior Miocene) - Uplift and change for climatic conditions more droughts. Processes of differential physical weathering. Bellowing of the base level and dissection of the South American surface; formation of new lateritic facies (Pliocene to Medium Miocene) - Processes of chemical weathering in humid and hot climatic conditions. Bellowing of the saprolit. Degratiom of the massive crusts inside plain surface in hydrated conditions and high biological activity; dissection of the residual surfaces and sedimentation (Superior Pliocene) - Uplift and chages for climatic conditions more droughts. Processes of differential physical weathering. Dissection of the residual surfaces; domain alternations between erosive and pedogenetic processes (Quaternaty) - Several short climatic oscillations, among the dry and humid. During the dry cycles, larger erosive activity and increase of the indent pf the slopes of larger steepness. During the humid cycles, larger pedogenetic and chemical activity.