Preliminary 39 Ar/ 40 Ar ages from the Socorro-Guaxupé nappe complex in souheastern Brazil: time-constraints on the final cooling of the southern Tocantins orogenic system and the superposition of the transpressive Rio Paraíba do Sul shear belt - Fetter, Allen Hutcheson; Hackspacher, Peter; Ebert, Hans Dirk; Dantas, Elton Luiz; Teixeira, Wilson (South American Symposium on Isotope Geology, 2003)