Após a última glaciação criogeniana (ca. 635 Ma), extensas plataformas carbonáticas desenvolveram-se sobre diversas regiões cratônicas da Terra e, apesar da intensa dolomitização desses depósitos, muitas informações paleoambientais e paleoceanográficas estão preservadas. Um dos exemplos mais importantes deste período no Brasil são os dolomitos da Formação Serra do Quilombo, pertencente à porção superior do Grupo Araras, no segmento norte da Faixa Paraguai, sul do Cráton Amazônico. A reavaliação estratigráfica da seção-tipo da formação e de uma seção de referência na região de Nobres, com base na análise de fácies e estratigráfica, permitiu ampliar as interpretações paleoambientais e elaborar um modelo deposicional. A sucessão estudada, de 140 m de espessura, inclui a Formação Serra do Quilombo em contato basal brusco com os calcários da Formação Guia e a passagem gradual para os dolomitos arenosos da Formação Nobres, no topo. A Formação Serra do Quilombo representa um megaciclo de raseamento ascendente, constituído por duas associações de fácies: 1) plataforma carbonática profunda à moderadamente rasa, composta por um dolomito fino laminado rico em matéria orgânica e outro maciço a laminado; e 2) face litorânea influenciada por tempestades, constituída por dolomito arenoso com estratificação cruzada hummocky/swaley associada com estratificação plano-paralela, dolomito arenoso/oolítico com laminações produzidas por ondas e brecha dolomítica com matriz. A Formação Serra do Quilombo representa o registro progradante de um trato do sistema de mar alto, em um contexto de rampa carbonática homoclinal instalada no sul do Cráton Amazônico durante o Ediacarano. After the last Cryogenian glaciation (ca. 635 Ma), large carbonate platforms were developed in several cratonic regions of the Earth and, despite the intense dolomitization of these deposits, paleoceanographic and paleoenvironmental pieces of information are preserved. One of the most important examples of this period in Brazil are the dolostones of Serra do Quilombo Formation, which belong to the upper portion of the Araras Group, exposed in the northern Paraguay Belt, south of the Amazonian Craton. The stratigraphic revaluation of this formation in its type-section and in a reference section in the Nobres region, based on facies and stratigraphic analyses, allowed to enlarge the paleoenvironmental interpretations and to propose a depositional model. The study succession of 140 m thick includes Serra do Quilombo Formation in sharp basal contact with the limestones of Guia Formation and the gradual contact, to the top, with the sandy dolostones of Nobres Formation, at the top. Serra do Quilombo Formation comprises a shallowing upward succession, which includes two facies associations: 1) deep to moderately shallow carbonate platform, composed of laminated dolostone rich in organic matter and a massive to laminated dolostone; and 2) storm influenced shoreface, consisting of hummocky/swaley to planar stratified sandy dolostone, sandy/oolitic dolostone with wave cross laminations and matrix-supported dolomitic breccias. Serra do Quilombo Formation represents the progradational record of a high-stand system tract, in a homoclinal carbonate ramp, installed on the southern part of the Amazonian Craton during the Ediacaran

On the southern edge of the Amazonian Craton, the Mirassol d’Oeste and Guia formations constitute the cap carbonate of the Araras Group. Petrography, X-ray diffraction, and quantification of terrigenous material allowed the identification of detrital grains (e.g., mica, quartz, and feldspar) in different proportions and diagenetic features. The sequential leaching of carbonates along a section of the upper portion of the Guia Formation yielded ⁸⁷Sr/⁸⁶Sr ratios increasing from 0.7070 to 0.7077, which is considered the primary Sr isotopic signature of seawater. The increasing continental influx of dissolved Sr from freshwater accounts for the increase in ⁸⁷Sr/⁸⁶Sr along the section. Such abrupt change toward more radiogenic values is also observed in carbonate layers soon after the Marinoan glaciation, elsewhere in the world. The same samples provided Nd-T_DM model ages (1.84–2.54 Ga) comparable with those of the continental crust of the Paleoproterozoic provinces of the Amazonian Craton, which forms the basement of the Araras Group. The Ԑ_Nd(635Ma) values between -4.7 and -11.1, probably indicate the presence of Nd from the suspended material transported by continental waters to the ocean where the carbonates precipitated. The random variations of Nd-T_DM ages and Ԑ_Nd values suggest important and rapid variations in the continental contribution to the post-Marinoan oceans.

The Macururé Domain, the largest unit of the Sergipano Orogenic System in NE Brazil, comprises a supracrustal succession intruded by numerous Brasiliano/Pan-African plutons. In this study, we present U–Pb and Lu–Hf isotopic data on detrital zircon from quartzites, integrated with lithological, geochemical and published geochronological results, to constrain provenance and tectonic setting. Detrital zircon U‒Pb spectra show prominent peaks at 2000–1980 and 1000–950 Ma, which correspond to the Paleoproterozoic Orogeny and the Cariris Velhos event. The Paleoproterozoic grains, with ε _Hf ( t ) values ranging from −15.6 to +0.5, and Archean model ages of 3.5–2.5 Ga indicate that crustal reworking dominated during Paleoproterozoic source formation. Tonian grains, with ε _Hf ( t ) values from −24.7 to +8.4 and model ages of 3.2–1.3 Ga, suggest contributions from both juvenile crust and ancient reworked components. These isotopic signatures differ from those of the São Francisco Craton and instead point to sources within the Borborema Province. The youngest grains (808–739 Ma) are contemporaneous with sedimentation and magmatism in the adjacent Canindé Domain, supporting a coeval basin development in an extensional setting, followed by basin inversion and continental collision at the onset of the Ediacaran.

The Arco Verde Complex, exposed in the Serra do Inajá region of the Rio Maria Domain (Carajás Province, Amazonian Craton), represents one of the oldest TTG granitoid association of the province (3.00–2.92 Ga). While TTG magmatism is well constrained in the northern domain, its southern sector lacks precise geochronological data. This study integrates petrographic, geochemical, U–Pb zircon geochronology, and Nd–Hf isotopes to constrain the age, source, and crustal significance of these granitoids. Uranium–Pb zircon dating of two granodiorites yielded ages of 2979 ± 8 and 2979 ± 11 Ma, extending the 2.98 Ga TTG magmatic episode to the southern sector of the Rio Maria Domain. Geochemical data indicate dominant tonalites formed by partial melting of a similar mafic source at different crustal depths, whereas subordinate granodioritic and monzogranitic rocks show transitional TTG affinities. These features indicate coeval mafic and felsic crust rapidly reworked after formation. Hf and Nd model ages of 3.0–3.2 Ga, with positive ε_Hf–Nd at 2.98 Ga, reinforce the Early Mesoarchean as the main crustal growth period in the province. In addition, we propose that the differentiation of the depleted mantle (DM) beneath the Carajás Province may have initiated around 3.8 Ga.