Carajas area

Deposits of Precambrian BIF, the rich iron ores of Cerro Bolivar in Venezuela (Ruckmick, 1963) and in the states of Para and Minas Gerais in Brazil (Dorr, 1969 Tolbert et al., 1973), are known. In the Sierra das Carajas area in Para, iron cherts were found not long ago in the rather inaccessible forests of the Amazon basin, and are not well known. 

In spite of the lessons from Jari, other large scale plantation development plans continue in the Brazilian Amazon. If developed, the Grande Carajas Program would consume large areas of tropical forest in the eastern Amazon in order to obtain charcoal for the smelting of pig-iron from the Carajas mines. The area of Eucalyptus plantation to produce the required amount of charcoal would be over 700,000 ha-more than 10 times the area of E. deglupta already cultivated in the Jari Project (Feamside 1989). 

Figure 1. The major geochemical provinces of the Amazon Basin, after Fittkau et al. (27). Location of the study areas in Manaus and Carajas are shown (25).

Cu-mineralized area of the Carajas region two weathering profiles that developed in contrasting rock types were investigated. One profile, developed in silicate rocks, contained complex clay minerals at the base, an intermediate kaolinitic zone and an upper iron-rich zone. The second profile developed in iron-rich silicate and... 

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