Re-Os and Sm-Nd isotopes systematics and contraints on the origin and age of the komatiites of the quadrilátero ferrífero, Minas Gerais, Brazil - Kirk, Jason Donald; Tassinari, Colombo Celso Gaeta; Munhá, Jose Manuel; Petronilho, Liliane Aparecida; Noce, Carlos Machado (South American Symposium on Isotope Geology, 2008)