Ages constraints in pegmatite province related to charnockitic host rocks in Minas Gerais, Brazil

Fernando Machado de Mello (1) , Essaïd Bilal (2, 3, 4)

1 DeGeo-IA - Departamento de Geociências-Instituto de Agronomia
2 SPIN-ENSMSE - Centre Sciences des Processus Industriels et Naturels
3 GSE-ENSMSE - Département GéoSciences et Environnement
4 EVS - Environnement, Ville, Société

Cambrian-Neoproterozoic granitoids suites in southeastern Brazil are the main host rocks of largest pegmatite field of Brazil, the Eastern Pegmatite Province. The P-Li-Nb pegmatites group represent the richest in precious stones like Beryl, Aquamarine, Topaz and Tourmaline. Two types of pegmatites are characterized by their mineralogical characteristics and tectonic and magmatic relations. The first group formed during compressive event about 582 Ma and the second pegmatite group was formed by cooling of residual melts during the transition to an extensional phase (520-500Ma) of the Brasiliano/Pan-African Orogeny, related to metamorphic rock melts (gneiss migmatite, gneiss) and extensive granite-charnockite emplacement. The new charnokite isotopic data presented here constrain the latest pegmatite genesis at about 500 Ma as its maximum age.

Mots clés: Geochronology Pegmatite Charnockite; Brasiliano/Pan-African; Magmatic and Tectonic Relationships; Minas Gerais-Brazil

Domaines: Génie des procédés; Géochimie; Milieux et Changements globaux

Fernando Machado de Mello, Essaïd Bilal. Ages constraints in pegmatite province related to charnockitic host rocks in Minas Gerais, Brazil. Romanian Journal of Mineral Deposits, 2012, 85 (1), pp.94-98. ⟨hal-00788995⟩