The bauxite of Porto Trombetas

Abstract

The Porto Trombetas deposits were discovered in 1950, and the open cut began in 1979. As ail the Amazonian deposits, the profile shows five layers that are, from the top to the bottom: a kaolinitic layer, a nodular bauxite layer, a ferruginous nodular layer, a bauxitic layer overlying an another kaolinitic layer. These layers previously described in Porto Trombetas (Aleva, 1981; Grubb, 1979) were the object of a very reœnt detailed study with emphasis on the petrological characteristics and its geochemical and pedogenetic consequences (Lucas, 1989) (see chapter III). The deposit of Porto Trombetas was also studied with more detail (Boulange & Carvalho, 1989) but the objective was mainly concentrated on the geochemical aspect and particularly on the distribution of the Rare Earth Elements (REE).