SERRA DO ESPINHAÇO MERIDIONAL: UM ORÓGENO DE COLISÃO DO MESOPROTEROZÓICO

Abstract

The Serra do Espinhaço Meridional (SdEM) is built mostly by Paleo- and Mesoproterozoic rocks of the homonymous supergroup. This supergroup includes sedimentary and volcanic rocks of the Guinda Group deposited between 1750 and 1700 Ma in a continental environment. The rift breakup generated a passive continental margin recorded by sedimentary and volcanic rocks (including banded iron formations) of the Serro Group.Tec tonic inversion occurred between 1.5 and 1.3 Ga. Syntectonic crustal stacking resulted in the formation of sedimentary throughs in fr ont of the orogenic belt, initially as a foredeep basin which is represented by deposits of the Conselheiro Mata Group, and later as foreland basins along the margins of the belt. During Late Mesoproterozoic times (about 1050 Ma) this orogenic belt underwent a mountain glaciation, recorded by the glaciogenic deposits of the Macaúbas Group along the borders of the SdEM. After an episode of intracontinental magmatism (Pedro Lessa Suite) the SdEM together with a large region of the adjoining São Francisco craton, was covered by an epicontinental sea and, by that time, carbonate and pelitic rocks of the Bambuí Group were deposited. The SdEM underwent uplift during the Late Neoproterozoic, causing local gravitional collapse of units of the Bambuí Group at the western border of this orogenic belt.