Figure 1:
Geological map of the São Francisco craton (Modified from Santos et al., 2000Santos R.V., Alvarenga C.J.S., Dardenne M.A., Sial A.N., Ferreira V.P. 2000. Carbon and oxygen isotope profiles across Meso-Neoproterozoic limestones from central Brazil: Bambuí and Paranoá Groups. Precambrian Research, 104:107-122.) and study area with location of stratigraphic sections. Sete Lagoas (SL), Haras Veredas (HV), Linha Verde (LV), Inhaúma (IN) and Funilândia (FN) sections (Modified from Ribeiro et al., 2003Ribeiro J.H., Tuller M.P., Danderfer A. 2003. Mapeamento Geológico região Sete Lagoas, Pedro Leopoldo, Matozinhos, Lagoa Santa, Vespasiano, Capim Branco, Prudente de Morais, Confins e Funilândia. Estado de Minas Gerais. Escala 1:50000 Texto explicativo PROJETO VIDA, Serviço Geológico do Brasil.).
Figure 2:
Stratigraphic column of the Bambuí Group according to Dardenne (1978Dardenne M.A. 1978. Síntese sobre a estratigrafia do Grupo Bambuí no Brasil Central. In: Congresso Brasileiro de Geologia, 30, Recife, Anais, SBG, v. 2, p. 597-610.) showing δ13C isotopic profile of the Sete Lagoas Formation from Vieira et al. (2007Vieira L.C., Trindade R.I.F, Nogueira A.C.R., Ader M. 2007b. Identification of a Sturtian cap carbonate in the Neoproterozoic Sete Lagoas carbonate plataform, Bambuí Group, Brazil. Comptes Rendus Geoscience, 339:240-258.) and ages presented from: (A) Buschwaldt et al. (1999Buchwaldt R., Toulkeridis T., Babinski M., Santos R., Noce C.M., Martins-Neto M.A., Hercos C.M. 1999. Age determination and age-related provenance analysis of the Proterozoic glaciation event in central-eastern Brazil. In: SSAGI, South American Symposium on Isotope Geology, Cordoba, Argentina, Actas, p. 387-390.); (B) Babinski et al. (2007Babinski M., Vieira L.C., Trindade R.I.F. 2007. Direct dating of Sete Lagoas cap carbonate (Bambuí Group, Brazil) and implications for the Neoproterozoic glacial events. Terra Nova, 19:401-406.); (C) Warren et al. (2014Warren L.V., Quaglio F., Riccomini C., Simões M.G., Poiré D.G., Strikis N.M., Anelli L.E., Strikis P.C. 2014. The puzzle assembled: Ediacaran guide fossil Cloudina reveals an old proto-Gondwana seaway. Geology, 42(5):391-394.); (D) Rodrigues (2008Rodrigues J.B. 2008. Proveniência de sedimentos dos grupos Canastra, Ibiá, Vazante e Bambuí - um estudo de zircões detríticos e idades modelo Sm-Nd. PhD. Thesis, Instituto de Geociências, Universidade de Brasília, Brasília, 128 p.); (E) Paula-Santos et al. (2015Paula-Santos G.M., Babinski M., Kuchenbecker M., Caetano-Filho S., Trindade R.I., Pedrosa-Soares A.C. 2015. New evidence of an Ediacaran age for the Bambuí Group in southern São Francisco craton (eastern Brazil) from zircon U-Pb data and isotope chemostratigraphy. Gondwana Research, 28(2):702-720.).
Figure 4:
Petrographic photos of the Sete Lagoas and Carrancas formations. (A) Fine limestones with thin clay layers and flame microstructures from Inhaúma section (sample IN-02). (B) Oligomictic massive diamictites showing angular quartz, feldspars and granitic rock fragments within fine matrix, carbonate cement and oxides from the base of Inhaúma section. (C) Impure limestones with interbedded clay layers, detrital sediments and oxides from Funilândia section (sample FN-15). (D) Recrystallized dolostones and impure limestones with interbedded clay layers, detrital sediments and locally deformed chlorite mica from Linha Verde section (sample LV-01). (E) Pure fine limestones (esparite) with calcite veins from the Sete Lagoas section (sample SL-18). (F) Pure limestones with some recrystallized carbonates and iron oxides cement from Haras Veredas section (sample HV-14). Scale bar 1 mm long.
Figure 8:
Sr isotope evolution curves of Neoproterozoic and Early Cambrian Global Ocean. Dashed blue lines limit the interval of 87Sr/86Sr ratios obtained in this study. Vertical bars represent global glaciations. Modified from Melezhik et al. (2001Melezhik, V.A., Gorokhov, I.M., Kuznetsov, A.B., Fallick, A.E., 2001. Chemostratigraphy of Neoproterozoic carbonates: implications for “blind dating”. Terra Nova, 13:1-11.), Halverson et al. (2010Halverson G.P., Wade B.P., Hurtgen M.T., Barovich K.M. 2010. Neoproterozoic chemostratigraphy. Precambrian Research, 182:337-350.) and Kuznetsov et al. (2013Kuznetsov A.B., Ovchinnikova G.V., Gorokhov I.M., Letnikova E.F., Kaurova O.K., Konstantinova G.V. 2013. Age constraints on the Neoproterozoic Baikal Group from combined Sr isotopes and Pb-Pb dating of carbonates from the Baikal type section, southeastern Siberia. Journal of Asian Earth Sciences, 62:51-66.).
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