FIG. 11. ⁸⁷Sr/⁸⁶Sr vs. time diagram showing the isotopic evolution of seawater (Veizer and Compston, 1976), continental crust and mantle (Faure and Powell, 1972) relative to the carbonate minerals from the matrix of mineralized breccias and crosscutting veins of the Igarapé Bahia Fe oxide Cu-Au-(U-REE) deposit. The Igarapé Bahia samples clearly indicate a crustal derivation. ACPS = Acampamento Sul orebody.