The Araçuaí Orogen (15°S - 21°S)
corresponds to the northern segment of the
Mantiqueira Province.
It was formed towards the end of the neoproterozoic Brasiliano / Pan - African cycle
(prior to the opening of the South Atlantic) as part of the evolution of
Western Gondwana
(see
geology).
This ancient mountain chain resulted from convergence of the
São Francisco
/ Congo Craton and the closing of an inland sea basin that connected in the north with
two alaucogens (Paramirim and Sangha) and in the south with a large Ocean (Adamastor).
Similar to its southern neighbour, the
Ribeira Orogen, nowadays only
the precambrian basement (partly covered by sediments) and a variety of granitic intrusions (plutons)
have remained.
