Estrutura dos Depósitos Sedimentares Quaternários da Bacia Hidrográfica do Rio Santana, Miguel Pereira, Estado do Rio de Janeiro

Abstract

The present work deals with stratigraphy, sedimentology and geomorphology of Quater-nary sedimentary deposits of Santana river hydrographic basin. through facies and arquitecturalelements descriptions. Based on five arquitectural elements characterized by ten lithofacies thefollowing structural and depositional evolutions were scheduled: 1) formation of thick soil horizons over the basement; 2) deposition of several alluvial fans on the soils (lithofacies Gm andFm, element E); 3) above an unconformity we can recognize a fluvial system, characterized by anon well drainage floodplain. This floodplain is overlaid by high-sinuosity channels (lithofaciesSp and St, element C) genetically related to other floodplain (lithofacies Fl and Fsc, element A)where the interfigering with crevasse splay deposits (lithofacies Sh, Sl, and Sp, element B) isususal; 4) an erosional phase suceed by a new depositional phase characterized by low-sinuositychannels (lithofacies Gp, Gt, Sp, St, and Sh, element D). Nowadays anthropogenic action pro-duces a new erosional phase. The geomorphological features recognized were scheduled: 1) thepresent floodplain 1.5m above the river bed; 2) the low terrace ( named T2) 5m above the riverbed and its deposits is related to element D; 3) the high terrace ( named T1) 11m above the riverbed and its deposits is related to elements A, B, C and E.

Keywords

• Quaternary deposits
• Santana river
• lithofacies