DEPÓSITOS QUATERNÁRIOS DA REGIÃO ENTRE MARÍLIA E PRESIDENTE PRUDENTE SP

Abstract (English)

Quaternary deposits occur extensively between Marília and Presidente Prudente (São Paulo State, Brazil), unconformably (with basal concentration of ferricretes and/or stonelines) or transitionally superimposed to Bauru Group and Serra Geral Formation cretaceous rocks. They are irregularly distributed throughout the study area, and have been grouped into colluvio-eluvial and alluvial deposits, according to sedimentological, morphological and genetical criteria. The colluvio-eluvial deposits are characterized by dominance of sands and clayey sands, with high mineralogical maturity. The thickest deposits are characterized by dominance of ?ne sands. Luminescence datings indicated Pleistocene age for colluvio-eluvial (9,000±1,000 to 980,000±100,000 B.P.) and alluvial (14,000±2,000 to 240,000±30,000 B.P.) deposits. These deposits have been installed on four peneplained surfaces shaped during the Quaternary: I (1,000,000 to 400,000 B.P.), II (400,000 to 120,000 B.P.), III (120,000 to 10,000 B.P.) and IV (10,000 B.P. until today). During the Quaternary erosion and sedimentation pulses of colluvial, colluvio-eluvial and alluvial deposits occurred, which were intercalated with soil development phases on cretaceous rocks. These events could be related to paleoclimatic changes and/or neotectonic activities, which caused baselevel changes with consequent relief transformations.