Abstract

The Santa Luz chromite-rich peridotite complex crops out in the Serrinha Block (NE São Francisco craton), approximately between grey gneisses of the Archaean basement and supracrustal rocks of the Palaeoproterozoic Rio Itapicuru greenstone belt. It comprises serpentinite, serpentinised harzburgite, massive chromitites, gabbroic pockets and amphibolite dykes/veins with epidote-rich margins, all intruded by pegmatite and aplite dykes. The mafic-ultramafic rock association is interpreted as basaltic melt percolation through mantle peridotites. Massive chromitites show major element chemistry and platinum group elements signature similar to ophiolite chromitites. The complex is older than 2085 ± 12 Ma and younger than 2983 ± 8 Ma based on U-Pb ages obtained respectively on aplite dyke and host banded gneiss. The Santa Luz peridotite complex and associated mafic dykes may be related to rifting of a magma-poor continental margin that later evolved into an ocean, the closing of which eventually formed the Palaeoproterozoic Rio Itapicuru greenstone belt.

Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call