Zircon U-Pb geochronology and Hf isotopes of the Luís Alves Terrane: Archean to Paleoproterozoic evolution and Neoproterozoic overprint

The Luís Alves Terrane in southern Brazil is one of the largest expositions Archean to Paleoproterozoic units that acted as basement for development Neoproterozoic Pan-African/Brasiliano orogenic belts Mantiqueira Province, South America. Combined field observations, petrography, Hf and U-Pb LA-ICP-MS zircon titanite isotopic data are presented this terrane. dataset spans a large time range with concordant ages from 3.2-1.8 Ga. Several magmatic metamorphic events recorded by reflecting complex evolution crustal block. oldest inherited grains have Mesoarchean (3.2–3.1 Ga), while two other populations yield 2683 ± 70 Ma 2498 11 Ma. Most crystallized during high-grade at 2352 23 2183 17 Titanite samples 2.02–1.99 Ga, probably retrograde trajectory re-equilibrated studied amphibolite-facies conditions. A late pegmatite dyke was emplaced between ca. 1.96 1.79 Cathodoluminescence images show analyzed samples, including those pegmatite, had their internal structure modified hydrothermal processes. localization outcrop close rim Campo Alegre Basin affected an important event well normal reverse discordant our indicate took place Brasiliano cycle end Neoproterozoic. isotope predominantly signatures ?Hf(t) values ranging 1.3 ?16.8. TDM model cluster groups (4.32–3.48 3.38–2.27 Ga) indicating pulses magma differentiation mantle subsequent mixing material high grade events.