This article presents data and interpretations on the Espinhaço Supergroup in Minas Gerais, emphasizingstratigraphic and structural data of the Serra do Espinhaço, where arise sequences from Archean (granites/gnaisses/migmatites and units of lower metamorphic degree) to Neoproterozoic. Espinhaço Supergroup hasit’s development in the end of the Paleoproterozoic until the Mesoproterozoic, and in the Meridional Sectionit’s base is represented by the Guinda Group, with quartzites, phylites and metaconglomerates/breccias offluvial to shallow marine origins, presenting intercalations of metavolcanics and real paleosoils (part ofhematitic phylites). Above arise eolian metasediments of the Galho do Miguel Formation and the marine tofluvial metasediments of the Conselheiro Mata Group. At the Setentrional Sector, three big groups, mainlypresenting continental characteristics (compatible with the opening of a rift), can be recognized formingthis super group in the setentrional sector of the mountain rage: Metavulcanossedimentar Unit, InferiorMetassedimentar Unit and Superior Metassedimentar Unit. The region is structured by a system of inversefaults/ ductile shear zones that cause frequent stratigraphic inversions and that spread marked blocks internallyby open folds to closed with West vergence. The analysis of quantity of deformation proves the non-axialcharacter of these mass transportations, and confirms the location of part of the shear zones.

This work present stratigraphic, mineralogical and geochemistry dates about  the “hematitic phyllites” of the Espinhaço Range, specially in its meridional portion. For these rocks, composed essencially by sericite/muscovite and hematite and very poor in quartz, many investigators have suggested an origin from a low grade metamorphism of some unique igneous rocks.Typical of the “Guinda Group”, basal portion of the Espinhaço Supergroup, with Paleo/Mesoproterozoic age (1.7 – 1.75 G.y.), the hematitic phyllites presents an interesting chemistry composition, characterized by 35,4% SiO2, 5,4% TiO2, 23,2% Al2O3; 25,3% FeO, 0,1% MnO, 1,5% MgO, 0,5% CaO, 0,3% Na2O; 7,9% K2O and 0,4% P2O5. These numbers shows, clearly, alteration processes.The evolutive aspects of the Espinhaço Supergroup put constraints that indicate one of the follow processes: modification from fluid percolation in shear zones or superficial alteration processes in atmosphere- lithosphere boundary. The present studies show that the last alternative (superficial processes) is more feasible to explain the characteristics of the hematitic phyllites.Thus, we believe that these rocks are paleoregolith/paleosols ( from Paleo/Mesoproterozoic) specially origined from the basalts of the “Espinhaço Basin” opening. Associated rocks with so much chloritoid (90.0%) are, probably, paleobauxities with variable iron content.

In this paper a brief review is given of master and doctoral thesis as well of articles published duringthe last 16 years, concerning the geology of the Serra do Espinhaço in Minas Gerais, Brazil. The differentproposals of a subdivision of the Archean basement and sedimentary sequences of Pre-Espinhaço age arereviewed. The existing geochronological data are insufficient for a complete understanding of these units.The Espinhaço rift started its evolution about 1800 Ma ago with continental sediments with intercalationof acidic and basic volcanics evolving in the upper part of the sequence to shallow marine sedimentation.Aspects of stratigraphy and sedimentology of the Espinhaço Supergroup as well as those of structuraland economic geology are briefly discussed. Diamonds washed in the Sopa-Brumadinho conglomeratesand in alluvials remains the principal mineral resource as about 160 years ago predicted by L.W. vonEschwege. In recent years exploration work was successful to identify the gold deposit at Riacho dosMachados in the northern extension of the Serra do Espinhaço.A chapter resumes the geodymamic models presented during the considered period. Finally, suggestionsfor future investigations are listed.

In the region of Desembargador Otoni – Planalto de Minas (Northeastern Minas Gerais State, Brazil) two stratigraphics units of Precambrian age were recognized: the Espinhaço Supergroup and the Macaúbas Group. The metapelites of the Macaúbas Group (rhythmites with associated diamictites) represent varvites wuth dropstones which cover with a pronounced angular and erosional unconformity units of the Espinhaço Supergroup. This supergroup is divided in lithostratigraphic units. The Planalto de Minas Formation (at the base) is composed by a thick sequence of greenschists (originates from metabasalts) with variable composition and textures, locally with intercalations of thin quartzites and phyllites. The Tapera and Serra do Atalho formations are built up by laminated, micaceous meta-arenites and pure or micaceous meta-arenites, normally with cross bending. Respectively. Intercalations of phyllites and greenschists occur in both units, in addition the Serra do Atalho Formation contains also hematitic phyllite and a thin intercalation of metarhyolite. This volcanic, volcanoclastic, and clastics units were deposited in a basin related to the initial phase (at about 1750 Ma) of crustal extension of the Espinhaço Rift.

The São Francisco Craton corresponds to an inner and stable portion of one of the plates involved in the assembly of Gondwanaland in late Neoproterozoic. To the east, the São Francisco Craton is limited by the Araçuaí-West Congo Orogen, which is composed, in its outer part, by the metasedimentary units of the Espinhaço Supergroup and Macaúbas Group. The cratonic adjacent area is mostly covered by the marine neoproterozoic units of the Bambuí Group, with few exposures of the Espinhaço Supergroup rocks. This paper aims to discuss the available geochronolgicl data and to present five new SHRIMP U-Pb dating on detrital zircons from rocks of the Bambuí Group and upper Espinhaço Supergroup at the eastern São Francisco Craton. The available dataset indicate that, within the São Francisco Craton, the upper portion of the Espinhaço Supergroup was deposited in the Pirapora Aulacogen through, in a period constrained between 1280 Ma (younger zircon population) and 933 Ma (age of the intrusive Pedro Lessa Mataigneous Suit). The cratonic basement highs (Sete Lagoas and Januária) seem to have been important source areas to the Mesoproterozoic units. The ages of the zircons found in the Serra de Santa Helena Formation suggest that its sediments may have come both from the Brasília Belt or the Araçuaí Orogen. On the other hand, zircons as young as 580 Ma, found in the Três Marias Formation sandstones indicate contribution from the Araçuaí Orogen. An important part of the sediment supply for the Espinhaço and Bambuí basins in the studied area could have come from older sedimentary units, as suggested by the great overlap in their detrital zircon age spectra. It demonstrates the remarkable polycyclic nature of the sedimentary processes who took place in the São Francisco Craton evolution Keywords: Geochronology, São Francisco Craton, Pirapora Aulacogen, Bambuí Group, Espinhaço SupergroupResumo: PROVENIÊNCIA SEDIMENTAR E BALIZADORES DE IDADE DE DEPOSIÇÃO DAS ROCHAS DO SUPERGRUPO ESPINHAÇO E GRUPO BAMBUÍ NA PORÇÃO LESTE DO CRÁTON DO SÃO FRANCISCO. O Cráton do São Francisco corresponde à porção interna e estável de uma das placas envolvidas na aglutinação do supercontinente Gondwana, no fim do Neoproterozoico. Em sua borda leste o cráton é limitado pelo Orógeno Araçuaí-Congo Ocidental, que é composto, em sua porção externa, por rochas metassedimentares do Supergrupo Espinhaço e do Grupo Macaúbas. A área cratônica adjacente é, em grande parte, coberta por rochas do Grupo Bambuí, à exceção de grandes anticinórios, como o da Serra do Cabral, que exibem, em seu núcleo, rochas do Supergrupo Espinhaço. Este trabalho objetiva apresentar cinco novas datações U-Pb SHRIMP em zircões detríticos de rochas do Supergrupo Espinhaço e do Grupo Bambuí aflorantes na região da Serra do Cabral, integrando-as com os dados existentes. Em conjunto, os dados indicam que, na área cratônica, a porção superior do Supergrupo Espinhaço foi depositada entre 1280 Ma (população mais jovem de zircões detríticos) e 933 Ma (idade de rochas intrusivas básicas). Os altos de Sete Lagoas e Januária parecem ter atuado como importantes áreas-fonte para as unidades mesoproterozoicas. Os zircões encontrados em siltitos da Formação Serra de Santa Helena apresentam fontes possíveis na Faixa Brasília e no Orógeno Araçuaí, enquanto zircões com c.580 Ma, encontrados na Formação Três Marias, devem ter fonte exclusiva no Orógeno Araçuaí. Grande parte dos sedimentos que preencheram as bacias Espinhaço e Bambuí parece ter origem em unidades sedimentares mais antigas, como sugerido pela grande interseção entre seus espectros de idades de zircões detríticos, o que demonstra o notável caráter policíclico dos processos sedimentares. Palavras-chave: Geocronologia, Cráton do São Francisco, Aulacógeno de Pirapora, Grupo Bambuí, Supergrupo Espinhaço