Soil evolution on Coastal Tablelands in northeastern Bahia, Brazil

Soil and landform coevolution seem to develop a significant influence on the Coastal Tablelands landscape of Bahia. This area presents Neogene sediments covering a cratonic region after intense dissection of the inland, forming Coastal Tablelands. Our goal was to understand the contribution of soil evolution to landform development using a multiscalar approach and investigating soil toposequences on both sides of a hillslope. Our results showed a drainage network controlled by regional lineaments. Tablelands are more dissected on litoral (convex tops) than in the inner (flat tops) due to the higher humite that comes from the ocean. Iron crusts sustain flat tops, but they are being transformed into other materials due to pedogenesis, forming a soil sequence of Argissolo (Lixisol) and Espodossolo (Podzol) in closed depressions found on flat tops with a higher water table. Hillslopes are dissymmetrically in deeper valleys with a lower water table, presenting more erosion of sand materials. In these hillslopes, the iron crusts appear in outcrops or deep into the soil with a toposequence of Latossolo (Ferralsol) and Argissolo (Lixisol). Soil transformation observed on the hillslopes shows a relationship between pedologic cover and landforms whose triggers for the changes are the lineaments and the height of the water table. To conclude, soil and landforms characteristics of Coastal Tablelands are influenced by the current processes, also working as a record of preterits times owing to pedogeomorphological evolution.