Mineralogy, geochemistry and parent rock of Décio bauxite-bearing lateritic profile (Rondon do Pará, Eastern Amazon)

Mineralogy, geochemistry and parent rock of Décio bauxite-bearing lateritic profile (Rondon do Pará, Eastern Amazon)

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Abstract Cenozoic world-class bauxite deposits developed on sedimentary sequences of the Parnaíba and Amazon Basins.The Décio pilot mine, excavated in the Rondon do Pará bauxite deposit, exposes a 3 m thick bauxite-bearing lateritic profile on the top of a 350 m high plateau.From the base to the top, this profile is composed of clayey bauxite; porous opheliasmuse.com microcrystalline bauxite; spherulitic ferro-aluminous duricrust, fragmentary on the top; as well as loose ferro-aluminous spherulites and nodules, embedded in clay.The lower horizons represent a tourettebrewing.com classic lateritic succession, while the top of the profile was produced through post-lateritic reworking.During this process, Ga, Cr, Mo, As, Pb, Hg, Sb, Zn, V and Sc were captured by the iron oxi-hydroxides; and REE, Hf, Nb, Ta, Y remained carried by relict zircon.

Isocon diagram and mass balance demonstrate the affinity of the bauxite with claystone from Itapecuru Formation.