Meta-evaporite in the Carajás mineral province, northern Brazil

Abstract

Evidence for connecting evaporite-sourced high-salinity fluids with iron-oxide–copper–gold (IOCG) deposits in the Carajas mineral province has solely been based on boron-isotope compositions of tourmaline. Presence of meta-evaporitic rocks remains unrecognised. Here, we report laminated albitite, tourmalinite and banded albite–phlogopite rock, intercepted by exploratory drilling in a clastic metasedimentary sequence. These rocks represent evaporite precursors. Their location in the copper–gold prospects Acai and Angelica, in the westernmost part of the Carajas mineral province, indicates that (i) evaporite-sourced fluids were regional and (ii) evaporite-bearing metasedimentary sequences may have been an important source of high-salinity fluids and/or sulfur for the IOCG deposits of the Carajas mineral province.