In the last decades integration between Geomorphology and Pedology has been used for landscape evolution research, resulting in soil-geomorphic models, some of them also considering stratigraphic aspects. However, little emphasis has been given on the application of these models to erosion processes studies, which methods generally take pedologic properties more important than geomorphological characteristics of soil sites, or even than soils space-time relationships. At the present study a methodology integrating pedologic attributes into geomorphologic and stratigraphic knowledge concerning Quaternary landscape evolution in hilly landforms of Southeastern Brazilian Plateau is used for surface water erosion investigation. The approach takes amphitheater-like headwaters as a basic geomorphological and pedological unit, where sedimentary sucessions are identified and mapped, on wich are recognized complete or truncated pedologic profiles.
Five amphitheater-like headwaters were selected, being identified Quaternary allo-units by stratigraphic sections and drilling, mapped considering their morphostratigraphic importance. Based on spatial distribution of surficial deposits and on the relationships with geomorphic components of headwaters, sampling points were selected for texture, flocculation ratio, aggregate stability in water, porosity, bulk density and organic matter analysis of surficial (0-15cm) and subsuperficial layers (15-30cm). The results demonstrated that surficial deposits with same pedologic classification present differences in aggregates size and micropores amount - pedologic properties observed as significant in definition of surface water erosion susceptibility. This susceptibility is also controlled by local topographic characteristics and by geomorphic setting inside amphitheater-like headwaters. In addition, recent deposicional units showed significative variations according to re-working materials (weathered bedrock and/or older Quaternary deposits).
Therefore, the use of Geomorphology and Stratigraphy represents an important approach to erosion studies on hilly domains of Southeastern Brazilian Plateau, suppling more precise data for definition of erosion risk areas.
*Supported by FUJB-UFRJ and CNPq