It is inserted in the DepressionSertaneja domain, composed of vast planed surfaces, also positioned in modest dimensions and by residual saws and plateaus that stand out about 300 meters above the pediplane floor. These reliefs are supported by the metamorphic igneous basement of the São Francisco Craton and by the Sergipana Folding Range. The flattened surfaces of the Sertaneja Depression consist of vast, flattened surfaces, invariably at low levels, between 100 and 300 meters. They are also inserted in the context of the great interplanaltic depressions of the Brazilian Northeast. This domain is composed of rocks from the Pre-Cambrian igneous-metamorphic basement of the Sergipana Folding Range, constituted by the Canindé, Poço Redondo, Marancó, Mucururé, Vaza-Barris and Estância domains (Santos et al., 1997) . | According to Almeida et al. (2000): This configuration results from a slow epirogenetic process that raised the Brazilian platform 200 meters during the Cenozoic. In this sense, the São Francisco River incised a deep canyon, reaching about 150 meters of relief (Valle Encaixados). The planed surfaces are undone in a frankly dissected low hill relief (Colinas Dissecadas and Morros Baixo). This fact can be attested by the recent fitting of the entire network of channels in adjustment to the general base level (relative sea level). In this sense, the São Francisco River incised a deep canyon. Distant about 200 kilometers from the mouth, the São Francisco river bed is positioned just 30 meters above sea level, showing a clear adjustment in relation to the current general base level. coastal, the chilly surface of the Sergipe Basin and with the Itabaiana Dome; and to the south, with the Palmares plateau. This geomorphological domain, according to the classification of the Brazilian relief, proposed by IBGE (1995), its configuration arises from an erosion surface and comprises a set of relief patterns, quite diversified, with predominance of flattened and smoothly This is the result of a process of widespread destruction of the relief over various types of lithologies, which spread in the southwest, central and western portions of the State of Sergipe and extend to the States of Bahia and Alagoas. |
Within the context of the classification of Ross (1985), this set of relief patterns, with slope 0 bigger than 5 and altimetric elevation between 10 and 30 m, are characterized as degraded planed surfaces. These prominent features were generated by differential erosion in plutons of Neoproterozoic age, very resistant to weathering and erosion, such as leukogranites from the Xingó Intrusive Suite; the granites, diorites, monzogranites and granodiorites of the Suites Intrusivas Cariri, Serra Negra and Itaporanga and the Granitoides Sítios Novos and Curralinho; and quartz-monzonites and quartz-syenites from the Serra do Catu Intrusive Suite. (Santos et al., 1997). The planed and chilly surfaces adjacent to the North of Sergipe, in turn, were modeled on an igneous-metamorphic substrate composed predominantly of amphibolites, migmatites, paragnaisses, metarritmitos, phyllites and marbles and orthogneisses, the Poço Redondo, Marancó and Canindé Migmatitic Complexes, of Mesoproterozoic ages; and the phyllites, metarritmites, metarenites and metagrauvacas of the Macururé Group (Santos et al., 1997).
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