Chemical analysis, XRD and SEM carried out in bauxites, Fe-rich and siliceous Fe-Al duricrusts of southeast of Amazonas state, associated to relief study, aimed to discuss the process that led to the formation and preservation of crusts through the geologic time. The crusts are massive, pisolitic, fragmental and vermiform textures, and support plateaus and hills with elevation between 200 to 320 m and 140 to 200 m, and developed from igneous and sedimentary rocks of Colíder and Alto Tapajós Group's and Supergroup Sumaúma. The correlation among lateritization products and rocks were defined for three main geochemistry associations: (1) that includes sandstones, volcanics and siltstones due to the association SiO2-Ba-Rb; (2) gathers bauxites and soils related to Al2O3-TiO2-PF-Y-Ta-Nb-U-Th-Ga-Hf-Zr-ETR; (3) brings together the pisolitic bauxite, Fe-rich and siliceous Fe-Al duricrusts assigned to Fe2O3- Ag-As-Ni-Pb-V. Geochemistry aspects and absence of quartz pebbles were used to recognize the protolith of bauxites and lateritic duricrusts, therefore massive bauxite and the overlapped soil belong to volcanics rocks. Sandstones of Supergroup Sumaúma are correlated with pisolitic bauxites and vermiform siliceous Fe-Al duricrust, however Alto Tapajós Group is related to the other crusts. The erosion was facilitated by the incision of Aripuanã, Acari and Sucunduri rivers; by the conditioning of grabens and horsts; and by dry seasons in Quaternary Amazonian that promoted the formation of truncated profiles with stone line exposures, dissected relief and thin soil.
Bauxite; Lateritic duriscrust; Geochemistry; Geomorphology
