A composição das aluviões do rio Neiva : indicadores do passado

The texture attributes of Neiva sediments were studied and compared to the Alvaraes Formation. There were identified two sedimentary sources for Neiva sediments. The Neiva River is eroding older deposits channel. The actual alluvium is enriched with the quartzite clasts from those deposits that are mixed with the recent materials eroded from the basin rocks. The recent sediments are mainly of granite gravels and sands. They are results of different weathering processes. The quartzite gravels and the Alvaraes Formation are indicators of chemical weathering processes at the source area. The recent material is supplied from the weathering conditions strongly influenced by the temperate climate. The Alvaraes Formation was generated by less competence fluvial streams