Sedimentary evolution of the Sete Lagoas formation (Bambuí group, northern Minas Gerais State) in the context of the upper Ediacaran sedimentary basins

Abstract

The transition between the Proterozoic and Fanerozoic eons is characterized by at least three major glacial events (Sturtian, Marinoan and Gaskiers), succeeded by a world wide carbonate sedimentation. The Bambuí Group (especially the Sete Lagoas Formation) has been the object of several sedimentological, geochronological and isotopical studies in the last decades, being associated with Sturtian or Marinoan glaciation. The occurrence of the guide fossil Cloudina sp. confirms a late Ediacaran age for the Sete Lagoas Formation and indicates that this unit is certainly younger than the glaciation Gaskiers. In the study area, located in Januária-MG region, there are virtually no studies focused on stratigraphic and sedimentological analysis for this unit. This lack of detailed studies preclude the full correlation of the Sete Lagoas Formation with coeval units in Brazil and South America as the exposures of the unit located in the southern portion of São Francisco craton. This project aims to conduct sedimentological and stratigraphic detailed studies in the Ediacaran successions of the Sete Lagoas Formation (Bambuí Group) in the region of Januária, north of Minas Gerais. In the proposed research will be used concepts of facies analysis, architectural elements, and paleocurrent analysis to compose a depositional and paleogeographic framework to the Sete Lagoas Formation and the analysis of sedimentary cycles for basal succession of the Bambuí Group. The isotopic values of C and O obtained from detailed sections also will support the palaeoenvironmental characterization of the water body in which the unit was deposited. (AU)