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The Aracuai-West Congo orogen (AWCO) is one of the various components of the Brasiliano/Pan-African orogenic network generated during the amalgamation of West Gondwana. In the reconstructions of Gondwana, the AWCO, encompassing the Aracuai orogen of South America and the West Congo belt of Southwestern Africa, appears as a tongue-shaped orogenic zone embraced by the Sao Francisco-Congo craton. Differing from the vast majority of the known orogens owing to its singular confined setting, the AWCO contains a large amount of orogenic igneous rocks emplaced in all stages of its tectonic evolution. We present new and revised information about the oldest Ediacaran granitic assemblage, the G1 Supersuite, which together with the Rio Doce Group defines the Rio Doce magmatic arc, and then we propose a new tectonic setting for the arc. Field relationships and mineralogical compositions of the G1 Supersuite allow us to characterize three lithofacies associations, Opx-bearing rocks, enclave-rich Tonalite–Granodiorite and enclave-poor Granite–Tonalite, suggesting different crustal levels are exposed in the central part of the Aracuai orogen. The region is interpreted to represent a tilted crustal section, with deep arc roots now exposed along its western border. Chemically, these plutonic associations consist mostly of magnesian, metaluminous to slightly peraluminous, calc-alkaline to alkali-calcic and medium- to high-K acidic rocks. The dacitic and rhyolitic rocks of the Rio Doce Group are mainly magnesian, peraluminous, calcic to calc-alkaline, and medium- to high-K acidic rocks. Zircon U–Pb data constrain the crystallization of the granitoids between ca. 625 and 574 Ma, while the age of the metamorphosed volcanic rocks is around ca. 585 Ma. Thus, within errors, these rock associations likely belong to the same magmatic event and might represent the subduction-related, pre-collisional, evolution of the Aracuai orogen. In addition, whole-rock Sm–Nd isotopic compositions show variable negative eNd(t) values between −6.7 and −13.8, and TDM model ages varying from 1.39 to 2.26 Ga, while eHf(t) vary between −5.2 and −11.7, with TDM ages from 1.5 to 2.0 Ga. Thus, predominantly constructed upon Paleoproterozoic (Rhyacian) basement, the Rio Doce arc shows crustal sources largely prevailing over mantle sources, providing a well-studied example to be compared with similar orogenic settings around the world.

In the southern South American platform, 2.5 to 2.0 Ga terranes, probably related to the Atlantica supercontinent, occur mainly as minor reworked inliers within Neoproterozoic, Brasiliano/Pan-African orogenic belts, as the Ribeira Belt in southern Brazil. The dispersion of such fragments has generated uncertainties about their geotectonic reconstruction, and their study has been supported mainly by elemental and isotope geochemistry. The southern Ribeira Belt lies between the Paranapanema and Luiz Alves cratons and contains reworked Neoarquean and Paleoproterozoic terranes which outcrop as basement nuclei in supracrustal sequences, as the Setuva Complex. The Agua Comprida Suite, situated in the northern part of the Setuva Complex, consists of Amphibole-Biotite Syenogranite ( ABS ), Porphyritic Biotite Syenogranite ( PBS ), and Equigranular Biotite Syenogranite ( EBS ). All granites are foliated and intensively deformed. The oldest foliation (S n ) is marked by augen feldspars set in a recrystallized matrix, followed by a crenulation cleavage (S n + 1 ) which evolves to discrete shear zones. ABS is a metaluminous, reduced A-type granite with FeO t / (FeO t + MgO) > 0.9, with high HFSE and REE contents, corresponding to magmas related to continental medium to high-K tholeiitic series. PBS and specially EBS are highly differentiated, metaluminous to peraluminous ( EBS ), oxidized granites. The increase of Al 2 O 3 and Rb, and decrease of HFS and RE elements relative to ABS indicate their evolution from tholeiitic magmas. The Agua Comprida Suite granites are cogenetic rocks evolved from a within-plate mantle source, marked by high Nb, Ta, and Y. The influence of previously metasomatised mantle sources is evidenced by negative Nb, Ti, and P anomalies. The age of ABS is 2187 ± 26 Ma, and that of PBS is between 2180 ± 13 to 2186 ± 22 Ma. The Nd model age of 2.4 Ga, and eNd (2.18 Ga) between − 0.23 and − 0.27 support the interpretation of ABS being formed from juvenile material with a minor crustal component. The deviation of eNd (2.18 Ga) for PBS and EBS (− 0.69 to − 2.65), plus the higher Nd model ages (2.4 to 2.5 Ga) suggest crustal contamination. A post-collisional environment for the interaction of the mafic tholeiitic and felsic crustal magmas is suggested for the formation of the Agua Comprida Suite, based mainly on geochemical features of these magmas. Post-collisional environments are still not described in the Rhyacian orogenies of southern Brazil, and this proposition may be an important contribution for the study of the final period of amalgamation of the Paleoproterozoic supercontinent in southern South America.

The Neoproterozoic geotectonic triad of the Brasiliano Orogen is reconstructed in southern Brazil from studies focused on the Porongos fold and thrust belt. We integrate field geology with isotopic studies of zircon U–Pb SHRIMP and Lu–Hf–O laser determinations in seven metasedimentary and three metavolcanic rock samples. The results indicate that the Porongos palaeo-basin was derived from mixed sources (3200–550 Ma), with major contributions from Rhyacian (2170 Ma) and Ediacaran (608 Ma) sources. Minor contributions from Archaean to Tonian sources are also registered. The maximum depositional age of the Porongos palaeo-basin is established by the age range of 650–550 Ma with TDM model ages between 2.5 and 1.3 Ga. The reworked signature (eHf values = −34 to −4) and the characteristic crustal magma reservoirs (δ18O ≥5.3 ‰) indicate that these sediments are equivalent to Neoproterozoic granites of the Dom Feliciano Belt. The episodic depositional history started in the Cryogenian (650 Ma) and lasted ...

The Paranapanema-Sao Francisco convergence is partially recorded in the arc-related high-K calc-alkaline intermediate magmatism of south-eastern Brazil (Southern Brasilia Orogen) during the West-Gondwana assembly. Similar geochemical affinities are widespread in the crustal fault-bounded slice, Sao Roque Domain, as in tectonic domains of the eastern Sao Francisco margin. The Sao Roque Domain comprises metavolcano-sedimentary sequences of Statherian maximum depositional age. Detrital zircon provenance points to a Rhyacian (2.17 Ga) proximal source belonging to the Socorro-Guaxupe Nappe basement. Unprecedented Tonian zircon U-Pb ages suggest a protracted evolution. The domain initiated magmatic activity at 680 Ma (Barro Branco orthogneiss) with weak Hf-Nd radiogenic signatures that agree with the arc evolution of the Socorro-Guaxupe Nappe. Granitoids grading from intermediate metaluminous to evolved peraluminous compositions intruded at 625 Ma (inequigranular orthogneiss) and 620 Ma (Moinho granodiorite). The most voluminous magmatism occurred within 610-590 Ma. Hf-Nd radiogenic compositions of the Ediacaran granitoids imply crustal participation. All granitoids have arc-related affinity with high Sr/Y and LREE, low Nb and Ti, and absence of Eu anomalies that indicate a lower crustal source with residual garnet (±amphibole ±rutile). The petrogenetic and geochronological characterizations favor a retro-arc setting for the Sao Roque Domain. Slab roll-back could have led to the northward migration of magmatism (Socorro-Guaxupe Nappe) producing a chronological gap in the retro-arc. The Ediacaran magmatism was probably triggered by the relaxation of the subducting angle. The last-longing subduction beneath the Paranapanema plate might have contributed to the high-K and radiogenic compositions through relamination. Monazite U-Pb ages from 630 to 600 Ma may be evidence of a thermal episode in the retro-arc, overlapping the syn-collisional metamorphism in the Southern Brasilia Orogen.

Paleoproterozoic terranes of the Man-Leo Shield in the southern part of the West African craton host one of the world’s largest gold provinces with an overall endowment >10,000 metric tons (t). Although gold deposition commenced by ca. 2170 Ma, most deposits formed later, either during the inversion and metamorphism of intraorogenic sedimentary basins between ca. 2110 and 2095 Ma, or during later transcurrent deformation and associated widespread high K plutonism following docking of Archean and Paleoproterozoic domains within the craton at ca. 2095 Ma. Deposits formed between ca. 2110 and 2095 Ma include those with free gold in quartz veins and refractory gold in arsenopyrite and/or pyrite, and are associated with halos of carbonate, sericite, chlorite, and albite alteration. Most are located in bends and intersections between shear zones, minor faults, folds, and entrained blocks of relatively reactive igneous rock. Conglomerate-hosted gold deposits of the Tarkwa district formed early in the 15-m.y.-long period. Gold deposits that formed subsequently between ca. 2095 and 2060 Ma have a wider variety of styles, geologic settings, and metal assemblages. District-scale albite, carbonate, and tourmaline alteration, hydrothermal breccias, and a close relationship to high K granitoids characterize some of these deposits, whereas others are more typical orogenic gold deposits that are similar to those formed earlier during the craton evolution.

The Turvo-Cajati Formation (TCF) is an important unit forming the Curitiba Terrane, a major segment of the southern Ribeira Belt, SE Brazil. It is composed of rocks of greenschist (LTCF), amphibolite (MTCF) and granulite (HTCF) facies conditions. Previous studies in the HTCF indicate that the unit underwent extensive partial melting under high-pressure conditions (670–810 °C and 9.5–12 kbar), within the kyanite stability field. In this paper, a study of the metamorphic zoning within the LTCF and MTCF is undertaken using pseudosection modeling in the NCKFMASHTO and MnNCKFMASHTO model systems coupled with detrital zircon U–Pb geochronology. Four metamorphic zones are recognized for the LTCF and MTCF: biotite, garnet, staurolite and sillimanite zones, with predominance of sillimanite zone and pressures lower than 8 kbar, as staurolite breaks down straight to sillimanite, without formation of a kyanite zone. Pseudosections yielded metamorphic peak conditions of ~530–560 °C and ~6–7.5 kbar (garnet zone) and ~660–690 °C and ~6–7.5 kbar (sillimanite zone). The metamorphic field gradient is flat and of low to medium pressure, below the typical Barrovian-type baric regime, and different from the HTCF. Available petrological and geochronological data suggest that the TCF comprises a paired low-P and high-P metamorphic belt, associated with a major Ediacaran suture zone in the southern Ribeira Belt. Probability density plots from detrital zircon U–Pb ages indicate late-Cryogenian-Ediacaran arc-related and Rhyacian sources for all TCF sub-units. This scenario suggests that the TCF is made up of a collisional juxtaposition of an accretionary wedge (HTCF) and a back-arc basin (LTCF and MTCF) on the border of a microplate, which includes a Rhyacian basement microcontinent, the Atuba Complex. It is inferred the high metamorphic gradient recorded in the LTCF and MTCF was related with asthenospheric upwelling in the back-arc region, which also produced extensive partial melting in the Atuba Complex basement.

International audience; The Serra das Pipocas Greenstone Belt is one of the rare Paleoproterozoic greenstone belts within the Borborema Province. It is on the west border of the Archean/Paleoproterozoic Nucleus (Cruzeta and Mombaça Complex) of the Ceará Central Domain, northern portion of the Borborema Province. The Serra das Pipocas Greenstone Belt has an elongated sigmoidal shape encompassing about 1000 km2 of the Ceará Central Domain. It consists of a metavolcanosedimentary sequence formed by metasedimentary psammitic-pelitic-marly rocks and interleaved metaultramafic and metamafic rocks, represented by chlorite-anthophyllite-actinolite/tremolite schists and amphibolites. Layers of metatuffs, metabasic, meta-acid sills (metadacites), metacherts, gondites and banded iron formations occur within the metamafic rocks. Actinolite, metagabbro, metadiorite bodies, metabasic dike, Neoproterozoic metagranodiorites and leucogranites crosscut the metavolcanosedimentary sequence. Close to the borders of metagranodioritic bodies (zircon U–Pb 2181 ± 4.4 Ma), the metavolcanosedimentary sequence is hydrothermally altered. The metaultramafic rock (chlorite-anthophyllite-actinolite/tremolite schist) contains high MgO (>18 wt%), low alkali (≤1 wt%) and TiO2 (

New petrography, geochemistry and Sm-Nd and Sr data from the orthogranulites of the Juiz de Fora complex in southern Rio de Janeiro State and compiled information provide insights on the petrogenetic and tectonic evolution. The complex comprises several geochemical groups including mafic orthogranulites (three tholeiitic and one alkaline) and felsic orthogranulites (three calc-alkaline and one tholeiitic/low K calc-alkaline). New geochemical and isotope data, combined with available U-Pb data suggest a long evolutionary history from the Paleoproterozoic to the Neoproterozoic. The oldest magmatic episode produced juvenile to slightly contaminated arc-type Rhyacian rocks, as well as granitic rocks related to collision or post-collision episodes. Altogether these rocks integrate part of a dismembered Rhyacian orogen within the Ribeira belt. Few TDM Nd model ages yielded 2.75 to 2.58 Ga, suggesting minor Archean contribution for magma genesis. Some of the basic granulites’ bodies yield Meso- to Neoproterozoic TDM Nd model ages, which may refer to an extensional magmatism. Orthogranulites present granulite facies paragenesis, related to the youngest tectonic episode in the Juiz de Fora Complex (Brasiliano Orogeny). The new data are potentially important for Paleoproterozoic reconstruction models, due to the predominantly juvenile character of the Juiz de Fora complex, as similarly worldwide.

The Precambrian basement of Northeastern Brazil is the product of Rhyacian block convergence. The main deformation and intrusion of crustal granitoids occurred between 2.15 and 1.8 Ga ago. This large area has been subjected to long-lasting and rather uniform stresses during the Cambrian period. Gold provinces in Bahia represent metallogenetic products of distinct tectonothermal events. Gold mineralization took place during the Paleoproterozoic collision and the Cambrian convergence, respectively, accompanied by heat flow, crustal deformation, and granite intrusion. The tectonic framework of the region was reconstructed at ca. 700 Ma ago, considering the hypothesis of wrench-fault tectonics. The new hypothesis provides geological evidence and metallogenic constraints that make further investigation necessary, with reference to well-established São Francisco Craton concept and its peripheral fold belts.

Minor altered intrusions and drab retrogressed schists can easily be overlooked in geological studies but this contribution explores these rocks within the Archaean and Palaeoproterozoic southern São Francisco Craton (SSFC), Brazil using geological relationships and accessory mineral in situ analyses in the context of cratonic assembly. Three magmatic pulses are documented: i) Archaean and ii) Palaeoproterozoic felsic intrusions, both hosted by Archaean protoliths, and iii) Palaeoproterozoic felsic intrusions in Palaeoproterozoic supracrustal sequences. Archaean felsic intrusions confirm the Palaeoarchaean age of the mafic/ultramafic sequence of the Rio das Velhas Greenstone Belt and Rhyacian intrusions mark the collisional stage of the Mineiro Belt with the SFC at c. 2130 Ma. Greenstone belt schists show a wide distribution of rounded ‘soccer ball’ Archaean detrital and metamorphic zircon grains ranging in age from 3200 to 2750 Ma with an interpreted overprinting high-grade metamorphic event at c. 2700 to 2680 Ma. Most high-grade metamorphic rims have Th/U > 0.1, negative εHf(t) values and REE pattern consistent with eclogite/granulite metamorphic facies, reinforcing the hypothesis of a dehydrated-refractory crust formed during the stabilization of the SSFC, even though no such protoliths are preserved. This event links crustal thickening and partial melting of Archaean lower crust. Archaean rutile crystals from the greenstone belt schist were reset during the Palaeoproterozoic event but still preserve the early Archaean high-grade metamorphic signature. The presence of unstable ilmenite replaced by rutile in the schist, associated to felsic intrusions with the same age at c. 2130 Ma suggest high pressure, low temperature prograde metamorphism during the collisional stage of the Palaeoproterozoic orogen. Elongate and prismatic zircon grains from the Rhyacian intrusions have low εHf(t) signature and crystallised from partial melting of sedimentary protoliths. Accretionary events produced thicker and more differentiated crust by the end of Rhyacian time. Easily overlooked rocks in this study, when studied, have revealed a rich multi-event history of cratonic evolution.

The Quadrilátero Ferrífero is an important mineral province located in Southern São Francisco craton, SE Brazil. Its prominent feature is the Gandarela syncline that was formed as part of the regional deformation event in the southernmost part of the craton at ca. 2,000 Ma. The syncline exposes several economically important units of Rio das Velhas and Minas supergroups, widely known for their gold and iron ore mineral deposits. This work focused on the upper Minas Supergroup — Cercadinho Formation and Sabará Group in the Gandarela syncline. We showed detail stratigraphic surveys combined with U-Pb detrital zircon analysis. Data reveal the development of high- to low-density turbidity systems. The first one is related to the deposition of Cercadinho Formation that marks the siliciclastic infilling of the Minas basin. For the Sabará Group, a fine turbidite system of foredeep depocenter is inferred. The detrital zircon analysis indicates that their sediments were derived from Archean, Rhyacian, and Orosirian exhumed terrains, besides granitoids positioned to the south and east of Quadrilátero Ferrífero. We proposed the age of 2,036 ± 25 Ma as the maximum age of deposition of Sabará Group, whose sedimentation occurs in the first stages of Minas accretionary orogeny.

The basal units of the Vazante Group, the Santo Antonio do Bonito and Rocinha formations, present different stratigraphic records and younger ages than the rest of the group. These units are characterized by diamictites, sandstones, pelites and rare carbonates originated from subaqueous gravitational sedimentation. U–Pb geochronological data in detrital zircon indicate a Tonian maximum depositional age for both formations. The youngest zircon grains yielded ages ranging from 903 to 935 Ma. The main source for zircon is Paleoproterozoic (mainly Rhyacian and Orosirian) to Mesoproterozoic (Calymmian and Ectasian) areas being probably the Sao Francisco paleocontinent the main area. Due to the complete absence of ice-rafted debris within fine-grained sediments in the Santo Antonio do Bonito Formation, we interpret a gravitational reworking as the main process of diamictites deposition, probably during a period of ice retreat and sea level rise. The U–Pb data corroborate a lateral correlation between the Santo Antonio do Bonito and Rocinha formations with the glaciogenic Jequitai Formation (Bambui Group). From east to west, glacial sediments of the Jequitai Formation were reworked probably by a slope-apron system during a late-glacial to post-glacial stage on the western margin of the Sao Francisco paleocontinent. Therefore, the Vazante Group can be divided into two successions: the upper Lagamar-Serra do Garrote formations and the lower Santo Antonio do Bonito-Rocinha formations. The Lagamar-Serra do Garrote sedimentation comprises a late Mesoproterozoic mixed carbonate-siliciclastic deposition in passive margins. The second succession is a gravitational slope-apron resedimentation and probably correlates with the Neoproterozoic glacial rocks of the Jequitai Formation from the Bambui Group. Finally, the collisional phase of the Brasilia Belt was responsible for stratigraphic inversion, placing the older Lagamar-Serra do Garrote formations over the younger Santo Antonio do Bonito-Rocinha formations.

The proximity and positions of cratons constituting the western Canadian Shield prior to and during the Rhyacian Period (2.30–2.05 Ga) are poorly known. In the absence of paleomagnetic data, stratigraphic correlation and detrital zircon isotopic data from sedimentary successions can be used to constrain relative craton positions during their time of deposition. The Murmac Bay Group, a multiply deformed metasedimentary succession located on the Rae craton margin in Canada, provides an opportunity to test hypotheses regarding its nearest cratonic neighbors during deposition. The polydeformed nature of the Murmac Bay Group, however, presents challenges in determining detailed stratigraphic relationships in the upper succession, which lacks distinct marker beds. Provenance analysis from detrital zircon geochronology provides one strategy for overcoming these challenges. Previous U-Pb geochronology indicates the lower succession was deposited 1.94 Ga. We provide new U-Pb detrital zircon ages for the upper succession, including a new maximum depositional age at 1.94 Ga). This provides an important constraint on the timing of Rae-Slave amalgamation.

This geochronological and isotopic study focuses on one of the Archean-Paleoproterozoic basement domains of the Sao Francisco craton reworked in the Aracuai orogen, the Porteirinha domain, Brazil. It also includes a thorough compilation of the U–Pb geochronological data related to the adjacent Archean and Rhyacian terranes from the Sao Francisco craton and Aracuai orogen. The main target of this study is the TTG gneisses of the Porteirinha complex (Sample 1). The gneiss dated at 3371 ± 6 Ma unraveled a polycyclic evolution characterized by two metamorphic overprinting episodes, dated at 3146 ± 24 Ma (M 1 ) and ca. 600 Ma (M 2 ). The former (M 1 ) is so far the most reliable evidence of the oldest metamorphic episode ever dated in Brazil. The latter (M 2 ), in turn, is endemic in most of the exposed eastern cratonic margin within the Aracuai orogen. Whole-rock Sm–Nd analysis from the gneiss provided a slightly negative eNd (t3370) = - 0.78 value, and a depleted mantle model (T DM ) age of 3.5 Ga, indicating derivation mainly from the melting of a ca. 3.5 Ga tholeiitic source. Sample 2, a K-rich leuco-orthogneiss from the Rio Itacambiricu Complex, was dated at 2657 ± 25 Ma and also presents a ca. 600 Ma M 2 overprinting M 2 age. The other two analyses were obtained from Rhyacian granitoids. Sample 3 is syn-collisional, peraluminous leucogranite from the Tingui granitic complex, showing a crystallization age of 2140 ± 14 Ma and strong post-crystallization Pb*-loss, also ascribed to the Ediacaran overprinting. Accordingly, it is interpreted as a correlative of the late Rhyacian (ca. 2150-2050 Ma) collisional stage of the Mantiqueira orogenic system/belt (ca. 2220-2000 Ma), overprinted by the Ediacaran collage. Sample 4 is a Rhyacian post-orogenic (post-collisional), mixed-source, peralkaline, A 1 -type suite, with a crystallization age of 2050 ± 10 Ma, presenting an important post-crystallization Pb*-loss related to Ediacaran collision. The focused region records some of the oldest magmatic and metamorphic events ever found in the Sao Francisco craton basement, a ca. 3.4 Ga TTG generation and ca. 3.1 Ga metamorphism, as well as two younger orogenic events: the Rhyacian (2.15–2.05 Ga), accretionary event, correlated to the Mineiro belt, and the Ediacaran Brasiliano overprinting, event imposed by the Aracuai orogen.

The Brasilia thrust and fold belt developed in the course of Neoproterozoic Brasiliano orogeny, during the convergence of Sao Francisco, Amazonian and Paranapanema cratons, in an early phase of Gondwana agglutination. A Paleoproterozoic terrane cropping out in its northern segment represents the basement of the belt and corresponds to a magmatic arc. The arc developed during Rhyacian, possibly on the margin of an Archean-Paleoproterozoic block that is today represented by the Sao Francisco craton. The Paleoproterozoic arc evolution starts following a calc-alkaline trend between 2.30 and 2.16 Ga, changing from a typical juvenile to crustal contaminated terrane with slightly negative ɛ Nd( t ) values, as revealed by tonalites and granodiorites of Conceicao do Tocantins Suite. By c. 2.17–2.15 Ga, a collisional event took place, triggering crustal melting and generating peraluminous granites. These syn-collisional granites present strongly negative ɛ Nd values and belong to Aurumina Suite. Natividade, Almas-Conceicao do Tocantins and Cavalcante-Arraias domains within the basement do not represent distinct tectonic blocks. The first two are areas where mainly plutonic arc rocks crop out and in the last one, syn-collisional granites are the most common lithology. Syn-collisional granites characterize granitogenesis produced by collision of another landmass against Sao Francisco landmass. The arc development is contemporary with collisional orogens that culminated in a conjectural Paleoproterozoic pre-Rodinia supercontinent. Since Rhyacian, these rocks are part of the landmass that would become the Sao Francisco craton and compose Brasilia Belt basement.

The period between the Rhyacian and Orosirian is known for the development of many orogenic belts and supracrustal sequences, which can be found in different cratons worldwide. In the northern part of the Sao Francisco Craton, there occur several Rhyacian-Orosirian sedimentary sequences associated with the orogenies that amalgamated the precursors of the Sao Francisco and West-Congo Cratons. However, little is known about the time and tectonic setting of sediment deposition. In this study we present U-Pb detrital zircon ages and provenance studies of sedimentary successions from the Paleoproterozoic Rio Capim greenstone belt, Serrinha Block, Sao Francisco Craton, Brazil. Detrital zircon data reveal a main sedimentary source of ages between 2.20 and 2.12 Ga, and indicate protoliths deposition between 2106 and 2086 Ma in a pro-foreland type basin. The main age interval matches the arc-related magmatism of the Rio Capim and Rio Itapicuru greenstone belts. Additionally, an age interval of 2.35–2.25 Ga indicates a sedimentary contribution of unknown source, while ages between 2.8 and 3.2 Ga suggest the Archean basement source. Field features, U-Pb ages and major and trace elements data support the interpretation that the Rio Capim and Rio Itapicuru greenstone belt both could make up an arc complex. Lithostratigraphic and tectonic matches allow to suggesting that the Serrinha Block may have an African counterpart, namely the Ntem-Chaillu Block, West-Congo Craton.

Precambrian terrane boundaries are sites of diverse rock associations and structural complexity. Motions along the boundary zones are commonly related to the construction of ancient large continental masses. This seems to be the case in the Sao Francisco Craton, Brazil, where three major blocks (Gaviao, Jequie and Serrinha) collided in the Paleoproterozoic to form the northern part of the craton. This manuscript presents zircon U-Pb ages and whole-rock geochemistry for rock associations on the western border of the Jequie Block, which is defined by the north-trending left-lateral 600-km long Contendas-Jacobina fault zone. The studied rocks are granulite to amphibolite facies Neoarchean orthopyroxene-hornblende granite gneisses of the Jequie block, which also occur tectonically imbricated within Paleoproterozoic metavolcanosedimentary rocks of the Contendas-Mirante belt. The rocks are 2.65-2.63 Ga high-K ferroan, metaluminous to slightly peraluminous syeno-monzogranite in composition, with negative ƐNd(2650) and Nd model ages of 3.05-2.88 Ga. They are depleted in Sr and Ti, enriched in Th, Ba and Pb enrichment, and have marked negative Eu/Eu*. This geochemical signature coupled with the Nd-isotope data indicate that the parental granitic magma was generated by crustal reworking of felsic Mesoarchean crust distinct from the western-sitting >3.3 Ga Gaviao Block. The investigated granitic gneisses are similar to other potassic granitoids that occur in the Sao Francisco Craton, which mark the thermal stabilization of the Archean lithosphere. The westward thrusting of the Neoarchean hornblende granitic gneiss and associated high-Mg tremolitite (meta-basalts) onto Paleoproterozoic volcano-sedimentary sequences establishes field evidence of Paleoproterozoic nappe stacking before lateral displacement during block collision. The crustal amalgamation is related to the assembly of the Sao Francisco-Congo Craton, a major landmass established before the Columbia supercontinent.

The Sao Francisco paleocontinent comprises Archean nuclei and Paleoproterozoic magmatic arcs which were amalgamated during Siderian to Orosirian thermal-tectonic events (ca. 2.4–2.0 Ga). Located in the Porteirinha domain, one of these Archean segments, the Riacho dos Machados metavolcanosedimentary sequence encompasses metamafites and metaultramafites intercalated with metasedimentary rocks. The metamafites clustered in the Type I category are tholeiitic, present MORB-like affinities and flat REE patterns with enrichment in La, Rb, and Cs. The metamafites from Type II are calc-alkaline, showing arc signatures with enrichment in LILE (Cs, Ba, U, Rb, K) and LREE, and depletion in the HFSE. The associated metaultramafites were classified as high-Mg ultramafic rocks similar to Barberton-Type komatiites, with enrichment in LILE and LREE, Al2O3/TiO2 1. U–Pb (LA–SF–ICP-MS) zircon analyses were carried out on the Type II hornblendite, unraveling a concordant crystallization age of 2071 ± 9 Ma. Inherited zircons yield a discordant age of 2922 ± 22 Ma and a lower intercept at 473 ± 48 Ma. The hybrid magmatism of the studied metamafites coupled with the inherited zircon grains, indicate that this metavolcanosedimentary sequence was developed in an intra-continental back-arc basin. The rocks from Type I have been originated from MORB-like source with a slightly input of subduction-derived fluids. In its turn, Type II samples represent melts more influenced by the fluids from the dehydrated slab. This assumption implies that the Sao Francisco paleocontinent, in the region of the Porteirinha block and surroundings, were under an accretionary stage at the late Rhyacian. During this orogenic process the metamorphic PT conditions reached lower-amphibolite facies. Moreover, this thermal-tectonic event in likely responsible for the auriferous fluid percolation of the Riacho dos Machados Gold Mine.

Paleoproterozoic (Rhyacian) rocks dominate within the basement of the Neoproterozoic Brasilia Belt and their genesis has been attributed to the orogenic amalgamation event that assembled the Sao Francisco-Congo paleocontinent from 2.18 to 2.07 Ga. However, the tectonic framework and genesis of the building blocks involved in this continent-wide amalgamation event are unclear, particularly in relation to terranes from the Almas-Conceicao do Tocantins Domain, in the Goias Massif, central Brazil. This work provides new whole-rock chemical and geochronological data, which indicate the generation of felsic to intermediate magmatism around 2.29 and 2.28 Ga corresponding to the Monzogranitic Unit and the Quartz-dioritic Suite, respectively. Later magmatic events occurred in a continental arc setting, around 2.26 to 2.2 Ga represented by metaluminous to peraluminous I-type magmatism of the Granodioritic to Tonalitic Suite (GTS) and the Serra do Boqueirao Suite. Around 2.2 to 2.18 Ga a peraluminous I-type magmatism took place and generated the Peraluminous Suite (PS). Our data show that after an earlier Siderian magmatic event around 2.45–2.34 Ga, reported in previous works, the Almas do Conceicao do Tocantins Domain oversaw additional Rhyacian events of magmatic activity around 2.29 Ga to 2.18 Ga. Regional geotectonic correlations with the Sao Francisco Craton and other pericratonic belts indicate coeval magmatic events taking place during the early stages of the Columbia Supercontinent amalgamation.

The southern sector of the Paleoproterozoic Lourenco domain in the central-eastern region of the Amapa state, northern Brazil, consists mainly of Rhyacian granite-greenstone terranes with some Archean fragments. It is located at the transition with the Archean Amapa block, a Meso-Neoarchean continental landmass (2.85–2.60 Ga), strongly reworked during the Transamazonian orogeny (2.26–1.95 Ga). Geochemical and petrographic data together with combined zircon U–Pb and Lu–Hf (LA-ICP-MS) as well as whole-rock Sm–Nd (TIMS) dating, establish the chronology and petrogenesis of the granitoids and record the crustal growth and reworking at the transition between the Archean and Paleoproterozoic domains in the southeastern Guiana Shield. Two episodes, dated at ~2.18–2.16 Ga and 2.14–2.13 Ga, respectively, include medium-to high-K calc-alkaline and metaluminous to peraluminous rocks of the Flexal and Papa-Vento intrusive suites, emplaced in a magmatic arc environment. A third episode, dated at ~2.08 Ga, encompasses mostly peraluminous granites with a medium-to high-K calc-alkaline signature, of the syn-to late-collisional Vila Bom Jesus Suite. The zircon ƐHf (−3.5 to −4.3) and whole-rock ƐNd (−2.7 to −4.3) signatures with respective Hf-TDMC (2.9–3.1 Ga) and Nd-TDM (2.6–2.7 Ga) model ages indicate a mixture of Rhyacian juvenile material with a Mesoarchean crustal component for the magma sources of the Flexal and Papa-Vento intrusive suites. The geochemical characteristics, zircon ƐHf (−6.6 to −12.5) and whole rock ƐNd (−3.7 to −5.4) signatures, and Hf-TDMC (2.9–3.6 Ga) and Nd-TDM (2.7–2.9 Ga) model ages, together with the presence of Rhyacian (2.19 Ga) and Mesoarchean (2.82 Ga) inherited zircon crystals in the Vila Bom Jesus Suite, indicate dominant crustal reworking of Rhyacian magmatic arc rocks and Archean rocks from the adjacent Amapa Block during the arc-continent collision. The geochemical and isotopic signatures of the magmatic arc granitoids (Flexal and Papa-Vento intrusive suites) may be attributed to the incorporation in the juvenile magmatic sources of Archean continental sediments or hidden crustal fragments from the Amapa Block during the subduction processes. Geochemical affinities with continental magmatic arc and subchrondritic Hf–Nd isotopic signatures are consistent with a scenario of a long-lived Mesorhyacian (~2.20–2.13 Ga), Cordilleran-type magmatic arc setting, which evolved to a collisional setting with the amalgamation of the Archean Amapa block and the Rhyacian Lourenco domain during the Neorhyacian (2.11–2.08 Ga).

Geological, U-Pb (detrital zircon), whole-rock Nd isotopes, and geophysical information constrain the timing, provenance, and depositional and tectonic settings of sedimentary successions from the Gurupi Belt (GB) and Sao Luis cratonic fragment (SLCF) in northern Brazil. The results, along with published information about the magmatic events are used to discuss the crustal framework and regional correlations. We defined the following stages of sedimentation related to the Rhyacian and Neoproterozoic-Early Cambrian evolution. (1) 2240–2160 Ma –metavolcano-sedimentary sequences formed in arc- (SLCF) and back-arc (GB) basins. (2) 2165–2120 Ma – two syn-orogenic, siliciclastic (turbidite) sequences; the oldest (>2149 Ma) formed in a forearc or intra-arc setting, the youngest (>2116 Ma) formed in forearc or distal intra-arc system. (3) 2120–2088 Ma – post-collisional, continental, siliciclastic basin(s) formed in fluviatile setting, and representing a foreland system, which was split into two sub-basins in more recent times. These Rhyacian sequences correlate with similar successions in the West-African and Amazonian cratons, and formed during the agglutination of a continental block in pre-Columbia times (>2000 Ma), which remained joined through the assembly (~1800 Ma) and breakup (~1300 Ma) of Columbia, being only fragmented during Rodinia breakup (~750 Ma). This breakup produced, probably distal, intracontinental effects that led to the deposition of (4) 1130–740 Ma – siliciclastic sequences formed in rift and passive margin basins; no evidence of oceanization is observed, and the sequences correlate in time with sedimentary formations of the Rokelide Belt in West Africa. The closure of the epicontinental sea took place during intracontinental orogeny, which represents a distal effect of the collisional orogenies that assembly West-Gondwana at the Neoproterozoic-Early Cambrian boundary. The last sedimentation event comprises (5)

The southeastern Guiana Shield, northern Amazonian Craton, is part of a Paleoproterozoic orogenic belt that was built up during the Transamazonian orogenic cycle (2.26–1.95 Ga). This cycle includes large segments of Rhyacian juvenile crust and some reworked Archean terranes. The geology in this region consists mainly of Paleoproterozoic granulitic-migmatitic-gneissic complexes, deformed and metamorphosed metavolcanic and metasedimentary rocks, and granitoids (granitic and TTG magmatism). Three tectonic domains are distinguished in the Brazilian territory of the southeastern Guiana Shield. They are known as the Amapa Block, Lourenco Domain, and Carecuru Domain. The Amapa Block is a Meso–Neoarchean continental block that was intensely reworked during the Transamazonian orogeny. The other two domains represent Rhyacian landmasses, the evolution of which involved several stages of subduction of oceanic lithosphere in magmatic arc environments. There are also relics of reworked Archean continental crust, the formation of which was followed by a collisional stage of tectonic accretion of the magmatic arcs. Whole-rock Sm–Nd and U–Pb zircon geochronology have confirmed the juvenile character of much of this Transamazonian orogenic belt. However, for the Lourenco and Carecuru domains, Nd isotopic signatures indicate the participation of Meso–Neoarchean crustal material in the sources of the magmatic rocks. Combined zircon U–Pb and Lu–Hf isotopic analyses by LA-ICP-MS were performed on eleven Rhyacian granitoids and orthogneisses from the Lourenco and Carecuru domains. The aim was to verify the extension of the influence of the Archean continental crust in the adjacent Paleoproterozoic domains. The main magmatic episodes were identified in the Lourenco Domain (~2.17–2.18, 2.14 and 2.12–2.09 Ga) and Carecuru Domain (2.14 Ga) by U–Pb zircon geochronology. The Lu–Hf isotope data point to the predominance of crustal reworking processes (ƐHf(2.2–2.1 Ga)

The basement of the northern Brasilia Belt, in Central Brazil, is dominated by large volumes of TTG magmatism generated during the Early Paleoproterozoic, and represents a continental block formed prior to the welding of the Sao Francisco paleocontinent during the Rhyacian, holding important information concerning the mechanisms and products of Paleoproterozoic crustal growth and amalgamation. New U-Pb zircon geochronological data was obtained from metagranitoids and mafic–ultramafic intrusions from the Almas-Conceicao do Tocantins Domain (ACTD). This was coupled with geochemical data from the metagranitoids to better constrain the processes of continental crust evolution in this region during the Siderian period. Two main plutonic episodes were recognized in the mapped area: (i) an early suite (2.47 Ga) dominated by tonalites and trondhjemites with subordinate biotite granites (Ribeirao das Areias Complex - RAC); and (ii) a later suite (2.30 Ga) including tonalites and trondhjemites (Ribeirao Itaboca Suite - RIS). Most of the RAC trondhjemite-tonalite-granodiorite (TTG) rocks are marked by fractionated REE patterns with high (La/Yb)N = 15–107 and samples have medium to high Sr/Y ratio (28–257). These TTG include both high- and low-Al types and high- and medium-pressure groups. The RIS TTG suite displays higher HREE contents with high (La/Yb)N = 65–89 and high Sr/Y ratio (59–95) and contains the high-Al type and the medium pressure group. In spite of the wide age gap between them, both RAC and RIS are characterized by TTG rocks formed in a subduction-like tectonic setting. The biotite granites are related to a magmatic stage after the TTG formation. Mafic rocks of the Gameleira Suite have an abundance of zircon, interpreted as crustal contamination, with dominant 207Pb/206Pb age populations of 2.48 and 2.30 Ga, and are interpreted to be associated with an extensional magmatic event following the Siderian period. Regional geotectonic correlations within the Sao Francisco Craton based on data compiled from the literature indicate a significant volume of Siderian crust generation that has been overlooked in continental amalgamation models and that TTG magmatism is a more common geochemical signature in Paleoproterozoic rocks than has been previously suggested.

Eoarchean to Rhyacian crust is preserved in the São Francisco Craton of eastern Brazil. To position this crustal segment in paleocontinental reconstructions, precise, accurate and robust geochronological data are necessary, especially for the diverse regional-scale mafic dyke swarms that crosscut the cratonic basement. This geochronological database can then be used to construct a magmatic barcode and compare it to the barcode of other cratons around the world, in search of similarities that might help to position these pieces in the paleocontinental puzzles. New Usingle bondPb SHRIMP contextual in-situ (thin section) dating of baddeleyite and zircon from six samples of three different dyke swarms in the southern São Francisco Craton, in addition to novel lithogeochemical and Ndsingle bondSr isotopic data, allow to pinpoint dyke emplacement at ca. 2.55 Ga (Lavras I swarm; εNd(t) = −6 to +2; TDM not calculable), ca. 1.8–1.7 Ga (Pará de Minas I and II dyke swarms; εNd(t) = −10 to −5; TDM = 2.5–3.0 Ga) and at ca. 900 Ma (Formiga dyke swarm; εNd(t) = −7 to 0; TDM = 1.4–2.3 Ga). The new geochronological data suggest a link between the regional dyke swarms and extensional stresses during the onset of crustal rifting related to the evolution of the Minas, Espinhaço and Macaúbas basins, respectively. A barcode comparison shows strong similarity between the São Francisco and North China cratons (Lavras-Taipingzhai/Naoyumen swarms, Pará de Minas-Taihang/Miyun swarms, Formiga/Pedro Lessa-Sariwon/Dashigou swarms; and possible correlations of the poorly dated 2.2–2.0 Ga Paraopeba swarm with similar aged swarms in North China), suggesting proximity of those two cratonic blocks, whether they were part or not of Proterozoic paleocontinents such as Columbia and Rodinia. The novel geochronological data support previous interpretations based on paleomagnetic data and provide further refinements of the geochronological record of the southern hemisphere cratonic blocks, allowing for better-tied global correlations.

A recently mapped area in central Brazil revealed a slice of Paleoproterozoic basement within Neoproterozoic metasedimentary rocks of the Brasilia Belt. The area, named here the Artulândia area for its proximity to the homonymous village, contains metatonalites and metagranodiorites in tectonic contact with a meta-volcanosedimentary sequence that encompasses felsic, intermediate and mafic metavolcanic rocks interlayered with clastic and chemical metasedimentary rocks. A sample of felsic orthogneiss from the metavolcano-sedimentary sequence, yielded a U–Pb zircon age of 2142 ± 4.4 Ma, which is interpreted as the crystallization age of the volcanic protolith. Samples from the metagranite unit returned U–Pb zircon ages of 2130 ± 7.4 Ma for a biotite metatonalite, 2157 ± 9 for a biotite metagranite, and 2147 ± 5 Ma for a sulfide-bearing metagranodiorite, indicating roughly contemporaneous plutonic activity. Whole-rock geochemistry shows calc-alkaline signatures for both units, and trace element results are compatible with an extensional setting, such as back-arc or intra-arc, for the metavolcano-sedimentary sequence, and a magmatic arc system for the metagranite unit. These rocks were generated in an episode of juvenile crust formation, as suggested by eNd(2.14Ga) values between 0 and + 3.18. Based on lithological association, age and chemical signature, we suggest that the studied rocks represent a lateral continuation of the Campinorte Arc beyond the Rio Maranhao Thrust. Thus, the occurrence of Campinorte Arc rocks on both sides of the thrust argues against the thrust being a Neoproterozoic collisional suture. The geology of the Artulândia area in the context of the Campinorte Arc attests to the complexity of the Rhyacian amalgamation that generated the Sao Francisco Paleocontinent during a Rhyacian Orogeny.

The age and tectonic setting of Mesoproterozoic to Neoproterozoic covers that occur along the southwestern margins of the Sao Francisco Craton (SFC) are still uncertain. This study reports new 207 Pb/ 206 Pb LA-ICPMS ages of detrital zircon grains from metasedimentary rocks of the Passos Nappe units and Canastra Group, and combined U–Pb and Lu–Hf analyses on igneous zircon from orthogneisses within the metasedimentary units. The U-Pb age spectra of detrital zircon grains of the Canastra Group comprises a wide range from ∼ 1.30-2.71 Ga with a significant Rhyacian component source ( ∼ 2.1 Ga). The second major source is represented by Statherian grains ( ∼ 1.6-1.7 Ga), and are similar to the Statherian interval at Espinhaco Basin. The youngest ages fall around ∼ 1.30 Ga. This peak age is compatible with the initial extension and sedimentation of the Carandai and Middle Espinhaco basins, which mark the second intracratonic rifting of the Sao Francisco Craton. Zircon grains from the metasedimentary rocks the Passos Nappe yielded a very prominent Rhyacian peak at ca. 2.10 Ga with some Statherian and Neoarchean contributions. All samples from the metasedimentary units show a prominent peaks at ca. 2.10 Ga, suggesting that most sedimentary sources derived from a Rhyacian substratum similar to the Mineiro belt, Natividade-Cavalcanti block, Campinorte Complex and Juiz de Fora Complex. Rhyacian age is compatible with U-Pb crystallization ages of felsic orthogneisses (2122 ± 67 and 2117 ± 23), enclosed as tectonic lenses in the Passos Nappe and the Canastra Group. These rocks show initial e Hf(t) values between +2.1 to -13.0 and +10.0 and -1.8, indicating that these orthogneisses are derived from Rhyacian granitic rocks, which were formed either by fractionation or re-melting of juvenile magmas, and by the reworking of more ancient, mainly Archean crust. The new data and regional geologic correlations suggest evidence of Paleoproterozoic terrain in the southwestern margin of the SFC.

The Rustenburg Layered Suite (RLS) of the Bushveld Complex, the largest ultramafic–mafic-layered intrusion on Earth, is associated with satellite intrusions and marginal sills with which it shares a common parental heritage (i.e. the B1, B2 and B3 parental magmas). The duration of the RLS emplacement is regarded as a focused event of less than 1 million years. Some of the more primitive satellite intrusions and marginal sills have been interpreted to predate the main Bushveld Complex. The precision and extent of existing age data, however, have not allowed confirmation of the relative timing of their emplacement. This study provides paleomagnetic support of a longer period of emplacement for the RLS and its marginal sills and satellite intrusions. Stepwise demagnetization of marginal sills with B1-geochemical affinity sampled regionally and associated with the exposed western and eastern limbs of the RLS reveals stable near antipodal components with improved grouping upon structural restoration of sills to their paleo-horizontal. 40Ar/39Ar dating of one of the studied sills indicates a crystallization age of 2058.5 ± 7.9 Ma. Although this age overlaps with the precise 2056–2055 Ma ages from the RLS, it is similar to seemly older ages reported from the lowermost part of the RLS and from other Bushveld-related units (e.g. pyroxenitic sills and Uitkomst Complex) with B1 geochemical affinity. A mean paleopole (λ = 26.63°N; ϕ = 036.02°E; A95 = 8.80; 20 sites) was calculated from tilt-corrected new and previous data from the 2058 Ma B1-marginal sills and Uitkomst Complex. This pole, which is assumed to be primary, is statistically distinguishable from the existing 2056–2055 Ma Bushveld Complex paleopole. This suggests a small, but appreciable amount of plate motion separating punctuated events of magma emplacement in the Kaapvaal Craton during the late Rhyacian Period. Our results support at least two episodes of magma emplacement in the formation of the RLS and its associated marginal intrusions. These are separated in time by a few million years (i.e. a B1-type magma pulse around 2058 Ma and the B2 and B3-type magma pulses following closely on each other around 2056–2055 Ma).

The Iriri-Xingu domain, located in the central part of the Amazonian craton, consists of extensive occurrences of Paleoproterozoic volcanic rocks and granites with published ages of ca. 1990 to 1840 Ma, which show a strong crustal contribution for their magmas. Exposures of basement rocks are small and rare. Samples from two areas were dated in this work by U-Pb SHRIMP in zircon. In the northern Maribel area, a high-grade pelitic paragneiss presented an age of 2160 ± 8 Ma and the leucosome of a migmatitic orthogneiss, probably a diatexite, crystallized at 2149 ± 20 Ma. These Rhyacian ages suggest that it is part of the Bacaja domain, related to the Trans-Amazonian cycle. The Morro Grande area occurs in the central part of Iriri-Xingu domain, where a high-grade muscovite gneiss with a protolith of 2120-2180 Ma is dated at 1982 ± 7 Ma, and the leucosome of a migmatitic orthogneiss is crystallized at 1979 ± 8 Ma. These are the first records of high-grade metamorphism at ca. 1980 Ma in the Central Brazil shield and may be related to the generation of this Orosirian felsic magmatism, which is widespread throughout the nearby Ventuari-Tapajos province.

New geochemical, U-Pb, Lu-Hf and Sr-Nd data from the Barreiro Suite metabasites in comparison with enclaves within the distal Andrelândia Group and the orthogranulites of the Juiz de Fora Complex are presented. Geochemical data suggest intraplate setting, with high and low- TiO 2 , TDM Nd ages between 1.80 and 1.41 Ga, negative ENd t and ( 87 Sr/ 86 Sr) i between 0.714 and 0.747. Results contrast with part of the Juiz de Fora Complex enclaves, with island arc tholeiites- calcalkaline basalts (IAT-CAB) geochemical signatures, TDM Nd ages between 2.58 and 2.16 Ga, positive ENd t values and ( 87 Sr/ 86 Sr) i between 0.700 and 0.712. U-Pb data for the Barreiro Suite yielded a crystallization age of 766 ± 13 Ma and a metamorphic overprint of 619 ± 6 Ma. The results indicate three episodes of mafic magmatism in the Occidental terrane of the Ribeira Belt. The two older episodes are related to Rhyacian arc evolution (ca. 2.2 to 2.1 Ga) and to the Statherian (ca. 1.7 Ga) tectonics, and occur only within the Juiz de Fora Complex, while the younger ca. 766 Ma episode constrains the timing of distal passive margin evolution. An important implication is that these late Tonian metabasic rocks could have been a source of detrital zircons for the sedimentation along the distal Andrelândia basin.

The Karouni deposit is located in central Guyana 35 km to the W of the former producing 5 Moz Omai mine and is interpreted to be an orogenic gold deposit. It is hosted in Rhyacian aged (2.2 to 2.1 Ga) volcano-sedimentary and intrusive rocks metamorphosed to greenschist facies. Detailed structural and crosscutting relationships, coupled with robust, new U-Pb geochronology on intermediate to felsic intrusive rocks and hydrothermal minerals from the Karouni camp have constrained the structural evolution of the deposit and provided a new age for gold mineralization with important implications for the structural framework and timing of gold mineralization throughout the region. Magmatism within the 200 km2 of the Karouni camp progressed from early, synvolcanic intermediate composition dikes at ∼2147 Ma to a major voluminous pulse of felsic magmatism coeval with regional deformation during the Trans-Amazonian Orogeny between 2120 and 2088 Ma. A late pulse of granitic magmatism at ∼1950 Ma may be related to a post orogenic event. Inherited zircons within the felsic intrusive rocks indicate assimilation of crust as old as 2223 ± 32 Ma. Gold mineralization associated with camp scale D2 deformation has been dated to 2084 ± 15 Ma on the basis of U-Pb geochronology of hydrothermal titanite. These results show gold mineralization is coeval with felsic magmatism and contemporaneous with a major pulse of orogenic gold mineralization in the Birimian Province of West Africa.

In French Guiana, the Montagne d’Or gold deposit (5 Moz at 1.5 g/t Au) is located in the northern branch of the Rhyacian Paramaca Greenstone Belt. The sulphide deposit is hosted by a south-facing bimodal volcanic and volcaniclastic sequence that is highly strained and affected by a penetrative E-W striking and steeply south-dipping foliation. The volcanic sequence is composed of three members, (1) the Lower unit in the stratigraphic footwall, (2) a bimodal mafic-felsic formation hosting the orebody, and (3) the Upper sedimentary and volcanic rocks unit in the stratigraphic hanging-wall. The bimodal formation is dominated by calc-alkaline felsic volcanic rocks in the west, interbedded/interdigitated with tholeiitic mafic rocks in the east. Pillowed mafic flows and graded-bedded felsic volcaniclastic rocks collectively indicate effusive to explosive volcanic activity in a submarine environment. The mineralization consists of thick and laterally extensive sulphide zones forming (1) stratiform sulphide disseminations, (2) structurally-transposed stringer stockworks, and (3) thin layers of deformed semi-massive sulphides. The gold-rich sulphide mineralization consists mainly of pyrite, pyrrhotite and chalcopyrite with minor sphalerite, magnetite, galena and arsenopyrite, hosted by chlorite-sericite-rich alteration zones mainly developed in the felsic tuff facies. U-Pb zircon geochronology shows that most of the Montagne d’Or volcanic and intrusive sequence has crystallized during a multi-cycle magmatic event, from ca. 2152 Ma to ca. 2130 Ma. A porphyry intrusion crosscutting the ore yields a U-Pb zircon age of 2117.6 ± 5.1 Ma, hence constraining a minimum age for the auriferous sulphide mineralization. This also indicates that the sulphide mineralization was coeval with arc magmatism, demonstrating the volcanogenic nature of the Montagne d’Or gold deposit.

Several high potassium-rich alkaline plutons from the Paleoproterozoic occur at the basement of the Sao Francisco craton, as well as at the basement of its surrounding orogens. Located in the western edge of the Sao Francisco craton, the Itacambira-Monte Azul block integrates the Aracuai orogen basement rocks, which were partially reworked during the Brasiliano tectono-metamorphic event. In this block, alkaline rocks from the Paciencia, Morro do Quilombo and Serra Branca plutonites are included in the Paciencia Suite. Petrographic studies within the Paciencia Suite show predominance of monzonites and syenites with equigranular to porphyritic textures and mafic enclaves. Chemical data indicate high concentrations of alkalis and enrichment in ferromagnesian oxides, which result in a high Mg#. These rocks are predominantly metaluminous, alkaline to alkaline-calcic and magnesian, enriched in Ba, Sr, Rb and depleted in Nb, P, Ti and other highfield strength element (HFSEs). Nonetheless, the contents of rare earth elements (REEs) are fractionated towards heavy rare earth elements (HREEs), showing higher concentrations of LREEs and negative to weakly positive Eu anomalies. The geochemical characteristics of these rocks are similar to potassic granitoids derived from ongoing subduction related to orogenic events, as the result of partial melting of a metasomatized mantle source enriched in incompatible elements and the input from an Archean crust. The crystallization age at 2053 ± 6.3 Ma indicates that the rocks from the Paciencia Suite are related to late stages of the Transamazonic orogenic event, associated with the evolution of an extensive arc magmatism developed during the end of the Rhyacian. Thus, the Paciencia Suite, as well as the other paleoproterozoic alkaline suites that occur in the basement of the Aracuai orogen, may represent the final stages of the stabilization of the Sao Francisco-Congo paleocontinent, in the Rhyacian–Orosirian transition.

Plutonic rocks from the Mineiro Belt, Brazil record a delayed onset of the transition from TTG to sanukitoid-type magmatism (high Ba-Sr), starting during the Siderian magmatic lull when little juvenile magma was added to the continental crust. Rocks mostly belong to the calc-alkaline series, meta- to peraluminous and originally “I-type”, meaning that oxidized magmas were formed by partial melting of subducted material. The temporal distribution and apparent secular changes of the magmas are consistent with the onset of subduction-driven plate tectonics due to an increase of the subduction angle and opening of the mantle wedge. New isotopic analyses (Sm-Nd whole rock and Lu-Hf in zircon) corroborate the restricted juvenile nature of the Mineiro Belt and confirm the genetic link between the Lagoa Dourada Suite, a rare ca. 2350 Ma high-Al tonalite-trondhjemite magmatic event, and the sanukitoid-type ca. 2130 Ma Alto Maranhão Suite. U-Pb dating of zircon and titanite constrain the crystallisation history of plutonic bodies; coupled with major and trace element analyses of the host rocks, they distinguish evolutionary trends in the Mineiro Belt. Several plutons in the region have ages close to 2130 Ma but are distinguished by the lower concentration of compatible elements in the juvenile high Ba-Sr suite. Keywords: São Francisco Craton, Magmatic lull, TTG-Sanukitoid transition, Zircon U-Pb-Hf, Titanite U-Pb, Whole rock Nd isotopes

Paleoproterozoic to Mesoproterozoic cratonic basins in the Sao Francisco Craton are classified into three megasequences: Statherian, Calymmian–early Ectasian, and Stenian–early Tonian sequences. The location, depositional age, and provenance of these sequences are reflected in their detrital zircon U–Pb age distributions. A minimum of five detrital zircon age distributions are distinguishable: i) the Archean and Rhyacian distribution, which is restricted to the Calymmian interval at Chapada Diamantina; ii) the Rhyacian distribution, which occurs in the Statherian, Calymmian, and Stenian intervals and generally precedes the Proterozoic distribution; iii) the Proterozoic distribution, which always succeeds the Rhyacian distribution and appears in the Brasilia Belt and Southern Espinhaco; iv) the mixed Archean and Proterozoic distribution, restricted to the Stenian interval at the Southern Brasilia Belt; and v) the Statherian distribution, which is present in the Statherian interval at Espinhaco Basin and is recycled into the Calymmian and Stenian intervals at Chapada Diamantina. Based on the Hf isotope compositions of the detrital zircons, most of the sequences are predominantly sourced from Archean juvenile terrains and from Archean and Paleoproterozoic evolved terrains. The exception is the Paranoa Group, western Sao Francisco Craton, whose positive ɛHf(t) values suggest juvenile Paleoproterozoic sources such as the Goias Massif. The Archean zircons from Chapada Diamantina have Hf depleted mantle model ages ranging from Paleoarchean to Neoarchean and are mainly derived from the Gaviao Block within northeastern Sao Francisco Craton. The model unify a dataset spanning hundreds of millions of years of the depositional record over a large area of central and eastern Brazil. The records will assist researchers in unraveling the sedimentary and tectonic history of the Archean and Paleoproterozoic continents from new data collected regionally and in other continents.

The bulk of the Atlantic shield basement in the eastern South American platform is made of Rhyacian calc-alkaline magmatic rocks (∼2.2–2.15 Ga) affected by granulite-facies metamorphism at around 2.06 Ga, as part of a Paleoproterozoic orogenic system which joined Archean crustal fragments together. Orosirian (2050–1800 Ma) rocks, on the other hand, are scarce in all four major provinces of eastern South America (the Borborema, Sao Francisco, Tocantins and Mantiqueira provinces). Recently, however, sparse occurrences of Orosirian-aged rocks have been described, particularly in the northern Sao Francisco Craton margin and adjoining fold belts that compose the Borborema Province further north. In this paper, we present new geochemical, geochronological and isotopic data of amphibolites which compose the basement of the Rio Preto fold belt, in the northwestern Sao Francisco Craton margin. Geochemical data suggest tholeiitic gabbro protoliths intruded in a subduction-related setting, as suggested by tectonic discrimination diagrams and differentiation trends. U–Pb analyses of magmatic zircon crystals yielded a 1958.3 ± 16 Ma Concordia age. Slightly negative to positive eNd (1.96) = (−0.3 to +1.0) and eHf (1.96) from −0.76 to −4.55 suggest variable mixing of a depleted mantle source and older continental crust. We interpret the amphibolite body as a remnant of a subduction-related crustal fragment developed in the Orosirian, around 1.96 Ga ago, possibly in a continental back-arc setting. This crustal fragment was further reworked as part of the basement of the Rio Preto fold belt during the Brasiliano Orogeny (∼600–550 Ma). The Cristalândia do Piaui Complex gneisses further north might represent fragments of a coeval continental magmatic arc. These rocks could be the first well documented representatives of an Orosirian tectono-magmatic event which has been, up to now, broadly ignored within this portion of West Gondwana, and thus present major implications for the Proterozoic crustal evolution of South America and for Paleoproterozic supercontinent reconstructions in general.

International audience; Piaba is an orogenic gold deposit (~ 3.5 Moz) of the São Luís cratonic fragment in north-northeastern Brazil. The deposit is epizonal–mesozonal and associated with the development of a subvertical strike–slip fault that cut across Rhyacian metavolcano-sedimentary rocks and granitoids. The metavolcano-sedimentary sequence comprises carbon-bearing schists, andesite/dacite, ultramafic rocks and felsic tuffs formed at 2240 ± 5 Ma to 2227 ± 33 Ma that were intruded at 2214 ± 3 Ma by fine-grained, subvolcanic granophyric granodiorite. Whole-rock geochemistry indicates that the hosting metavolcano-sedimentary sequence formed in a subduction-related (arc, back-arc?) setting, which has previously been interpreted as the early-arc stage of an accretionary orogen (2240–2214 Ma) that was followed by voluminous subduction-related calc-alkaline arc magmatism (2168–2145 Ma) and by a collisional phase (2100 ± 15 Ma) that produced several bodies of peraluminous granites. The hydrothermal alteration of the host rocks produced early, distal carbonization and hematitization and proximal, ore-related chlorite–sericite–carbonate–sulfide alteration. Two styles of mineralization, occurring in association, are present: (1) a network of thin quartz ± sulfide veinlets and subordinate narrow breccia veins with refractory- to free-milling gold dissemination in hydrothermally-altered host rocks, and (2) subordinate low-sulfide Au-quartz veins with free-milling gold. Fluid inclusions and stable isotopes characterize the mineralizing solution as a relatively reduced (log fO2 = − 30 to − 35), neutral to slightly alkaline (pH 5 to 6.2), low-salinity (average 5% NaCl), aqueous-carbonic (XCO2 = 5 to 59 mol%, XH2O = 40 to 93 mol%, XN2 and XCH4 < 1 mol%) metamorphic fluid (δ18OH2O = + 5.5 to + 8.9‰, δDH2O = − 8 to − 69‰), and suggest that gold mineralization occurred at 250° to 330 °C and 1.25 to 2.8 kbar in response to phase separation and fluid–rock interactions that produced sulfidation and minor carbonatization. Sulfur (δ34S = − 2.7 to − 3.8‰) is from an undetermined source, probably magmatic (oxidized) or sedimentary. Lead isotope compositions of gold, ore-related pyrite and K-feldspar from regional rocks suggest that collision-related granitoids of ca. 2100 ± 15 Ma are the most likely sources for Pb in the ore, although mantle and lower crustal sources are also observed. 40Ar/39Ar in hydrothermal sericite yielded a plateau age of 1980 ± 13 Ma, which is similar to the Pb–Pb model age of gold of 1959 Ma. These are considered the minimum age for gold mineralization, whereas the maximum age of 2009 ± 11 Ma is given by a small gold-hosting intrusion in the same region.

Zircon U–Pb–Hf and geochemical data provide new clues for a juvenile TTG segment in the Mineiro belt, outlined by published information about the nearby 2.35 Ga Lagoa Dourada suite. The Resende Costa Orthogneiss and coeval rocks yield U–Pb crystallization ages from 2351 ± 48 to 2317 ± 16 Ma and coherent Sm–Nd T DM ages between 2.3 and 2.5 Ga. These rocks show ɛ Nd(2.35Ga) and ɛ Sr(2.35Ga) values that suggest derivation from a short-lived, slightly depleted source akin to products of island arcs, whereas the geochemistry is consistent with a tholeiitic source with minor crustal assimilation. The positive to negative zircon ɛ Hf(2.35Ga) suggests the subordinate involvement of crustal components during the hypothesized c. 2.35 Ga slab subduction event. In a similar manner, metabasalts (lower unit) of the adjoining Congonhas-Itaverava belt show Nd–Sr isotopic and chemical constraints indicating derivation from an early Paleoproterozoic tholeiitic source subjected to crustal assimilation. A coeval metagraywacke from the upper unit yields U–Pb zircon detrital ages as young as 2349 + 14 Ma suggesting the maximum depositional age for the precursor basin (foreland setting?) whilst most of the grains indicate contribution from nearby Archean sources. The Resende Costa-Lagoa Dourada rocks characterize the precocious arc magmatism of the Minas accretionary orogeny . This composite orogeny created the Mineiro belt and the adjoining Mantiqueira and Juiz de Fora belts in the 2.35–2.00 Ga interval. Due to such a polycyclic framework the Resende Costa Orthogneiss and coeval rocks show multiple metamorphic overprints dated at 2140 and 2050 Ma. The new and compiled data and regional geologic correlations provide evidence for a growing Paleoproterozoic landmass in the South America continent.

The history of palaeocontinents alternates long fragmentation to drift periods with relatively short agglutination intervals. One of the products of a Rhyacian-Orosirian orogeny was a palaeocontinent that brought together the basement of the Araçuaí-West Congo orogen (AWCO) with regions now located in the São Francisco and Congo cratons. From ca. 2 Ga to ca. 0.7 Ga, this large region of the São Francisco-Congo palaeocontinent was spared of orogenic events, but underwent at least five taphrogenic events recorded by anorogenic magmatism and/or sedimentation. The taphrogenic events are well documented in the AWCO proximal portions and neighboring cratonic regions, but lack evidence in the AWCO high-grade core. Our studies on amphibolites intercalated in the Rhyacian Pocrane complex, basement of the Rio Doce magmatic arc, allowed to the recognition of two Mesoproterozoic taphrogenic episodes. The oldest one, a Calymmian episode, is recorded by amphibolites with a zircon magmatic crystallization age at 1529 ± 37 Ma (U-Pb SHRIMP), and lithochemical signature of basaltic magmatism related to continental intraplate settings. Another set of amphibolite bodies records the youngest taphrogenic episode, a Stenian event, with a zircon magmatic crystallization age at 1096 ± 20 Ma (U-Pb SHRIMP), and lithochemical signature similar to mature magmatism of continental rift setting. The Calymmian episode (ca. 1.5 Ga) correlates to the Espinhaço II basin stage and mafic dikes of the northern Espinhaço, Chapada Diamantina and Curaçá domains, while the Stenian episode (ca. 1.1 Ga) correlates to the Espinhaço III basin stage. We also present U-Pb data for 87 detrital zircon grains from a quartzite lens intercalated in the Pocrane complex, the Córrego Ubá quartzite. Its age spectrum shows main peaks at 1176 ± 21 Ma (35%), 1371 ± 30 Ma (18%), 1536 ± 22 Ma (19%), 1803 ± 36 Ma (17%) and 1977 ± 38 Ma (12%), suggesting a Stenian (ca. 1176 Ma) maximum depositional age (although only one zircon with low discordance shows an age of 955 ± 66 Ma). Comparing with data from the western sector of the Araçuaí orogen and São Francisco craton, it is noteworthy that no igneous zircon from the three samples yielded an age older than early Orosirian (~2.05 Ga), showing age spectra essentially limited in the range of ca. 1-2 Ga; i.e., younger than the Late Rhyacian orogeny that amalgamated the basement, and older than the main anorogenic event (930-870 Ma) associated with the Early Tonian precursor basin of AWCO. All together, these continental taphrogenic events testify the several unsuccessful fragmentation attempts that affected the long-lived São Francisco-Congo palaeocontinent, which remained preserved from a complete break-up associated with ocean spreading from the Early Orosirian to the Atlantic opening in Cretaceous time.

Because of its world-class iron ore deposits and promising Au and U mineralizations, the late Neoarchean to Paleoproterozoic Minas Basin (Minas Supergroup, SE of Brazil) is one of the best-studied basins in South America. However, the lack of datable interlayered volcanic rocks prevented discourse over ages of the strata, the sources and the nature of its ore deposits. In this paper, we present detrital zircon U–Pb age patterns coupled with Lu–Hf data for 18 samples, representing different stages of the Minas Basin evolution (∼2000 analyzed zircons). Age spectra for the main basal unit (Moeda Formation) show a classic rift-related detrital zircon pattern, characterized by multiple autochthonous sources, which in turn are much older than the age of deposition. Maximum age for the rifting event is constrained at ca. 2600 Ma. Detritus accumulated at the base of the Minas Supergroup were derived from Archean source rocks and their sedimentation was marked by differential uplift of the Archean crust, shortly after the 2730–2600 Ma high-K calc-alkaline magmatism (Mamona Event). The age of the BIF deposits is younger than 2600 Ma, most likely coinciding with the great oxygenation event between 2400 and 2200 Ma and the precipitation of banded iron deposits worldwide. Detrital zircons from the topmost units of the Minas strata suggest that tectonic inversion and closure of the basin took place at ca. 2120 Ma with the deposition of the synorogenic Sabará Group. Rhyacian zircon supply showing juvenile Hf signatures gives evidence of a late Rhyacian amalgamation between the Mineiro Belt and the craton. The εHf signatures support the hypothesis that the Archean crystalline crust of the craton was mostly built by crust–mantle mixing processes, with a successive decrease of εHf values in zircons crystallized after 3250 Ma and minor mantle-like additions after Paleoarchean times. Regionally, our dataset supports previous interpretations of a long-lived evolution of the southern São Francisco Craton comprising a succession of convergent island arcs, small microplate collisions, and development of Archean convergent and divergent basins that evolved between Archean and Paleoproterozoic times. Fil: Martínez Dopico, Carmen Irene. Universidade Federal de Ouro Preto; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Lana, Cristiano. Universidade Federal de Ouro Preto; Brasil Fil: Moreira, Hugo S.. University of Portsmouth; Reino Unido Fil: Cassino, Lucas F.. Universidade Federal de Ouro Preto; Brasil Fil: Alkmim, Fernando F.. Universidade Federal de Ouro Preto; Brasil

The Portalegre shear zone separates the Rio Piranhas-Serido and the Jaguaribeano geological terranes in the Northern Domain of the Borborema Province. Banded gneisses of the Caico and the Jaguaretama Complexes represent the basements of these terranes. U-Pb analyses yielded ages of 2,193 ± 16 Ma for the Jaguaretama Complex, which is similar to those obtained for the Caico Complex. T DM Sm-Nd ages for these basement complexes showed Neoarchean values (ca. 2.5 Ga), with eNd(t) values close to the CHUR composition. Elongated bodies were found intruding into the rocks of the Jaguaretama Complex. These foliated bodies with elongated phenocrysts are described as augen gneisses of the Serra do Deserto Suite. These gneisses yielded crystallization ages of 1,777 ± 8 Ma, confirming an extensional period during the Statherian, which is well represented in the Jaguaribeano Terrane by A-type plutonic rocks. Augen gneisses with similar textures, the so called Poco da Cruz Suite, are found intruding the Caico Complex in the Rio Piranhas-Serido terrane; however, the ages found throughout the domain are predominantly Rhyacian (ca. 2.2 Ga) and present calc-alkaline affinities. These findings indicate that the augen gneisses, which are widely distributed in these two terranes, have different signatures and are temporally well separated. Furthermore, in agreement with previous geophysical data suggesting a division of terranes marked by the Portalegre Shear Zone, it also demonstrates that even though the Caico and the Jaguaretama Complexes have similar ages, similar structural evolution and metamorphism under similar pressure and temperature conditions, they exhibit marked differences in composition.

The Borborema Province is the western part of a major Brasiliano belt that extends from Brazil through NW Africa in pre-drift reconstructions. This province resulted from convergence and collision among the West African, Congo-Sao Francisco, and Amazonian cratons about 600 Ma. This study focuses on the Pernambuco–Alagoas (PEAL) domain, which is a complex of magmatic, migmatitic, and metamorphic rocks, located in the southern part of the Borborema Province. U–Pb geochronology and Sm–Nd data for metasedimentary sequences (Rio Una, Inhapi) of the PEAL domain and a sample from a sequence of the Transversal Zone domain suggest that their deposition occurred during a Cryogenian extensional event, within the interval 850–631 Ma (or slightly younger). This extensional event occurred in the PEAL, Transversal Zone, and Sergipano domains before the onset of the Brasiliano collision and was followed by syn- and post-collisional magmatism. The Rio Una sequence and the sequence from Transversal Zone domain were deposited over a Rhyacian (ca. 2.0–2.2) basement having a juvenile Palaeoproterozoic Nd signature, whereas the Inhapi sequence was deposited over an Early Neoproterozoic (Tonian) basement. The deposition of the studied sequences is coeval with metasedimentary sequences to the north and south in other domains of the Borborema Province. However, differences in Nd isotopic signatures between the sequences from PEAL, Transversal Zone, and Sergipano domains suggest that they were formed in distinct basins. Metasedimentary sequences from the PEAL domain have Meso- and Palaeoproterozoic T DM model ages. These data suggest that the orogens where the metasedimentary sequences are located have a strong ensialic component. T DM model ages of ca. 1.0 Ga and eNd (0.6 Ga) values around zero recorded in granites from the southern part of the PEAL, suggesting that juvenile material was accreted to the southern part of the PEAL domain crust during the Tonian. The migmatites from the PEAL domain have a wide range of T DM ages along with a wide range of eNd (0.6 Ga) values. The transition between the northern and southern parts of the PEAL domain denotes the approximate northern margin of a Late Mesoproterozoic to Early Neoproterozoic rift.

Caxias is an orogenic gold deposit in the São Luís cratonic fragment, which is correlated with the Rhyacian terranes of the West-African Craton. The deposit postdates peak metamorphism (estimated at 2100 ± 15 Ma) and is hosted in a shear zone that cuts across schists of the Aurizona Group (2240 ± 5 Ma) and the Caxias Microtonalite. The emplacement age of the microtonalite, as determined in this work by SHRIMP U-Pb zircon dating, is 2009 ± 11 Ma and represents a late-stage magmatic event in the São Luís cratonic fragment. Older zircon age of 2139 ± 10 Ma is interpreted as due to inheritance from the older granitoid or volcanic suites (magmatic sources?) or to contamination during emplacement. Lead isotope compositions indicate that the Pb incorporated in ore-related pyrite was probably sourced from regional, orogenic calc-alkaline granitoids of ca. 2160 Ma. Hydrothermal sericite from Caxias yielded a 40Ar/39Ar plateau age of 1990 ± 30 Ma, which combined with the emplacement age of the Caxias Microtonalite brackets the age of gold mineralization between 2009 ± 11 and 1990 ± 30 Ma. Caxias é um depósito de ouro orogênico do fragmento cratônico São Luís, que é correlacionável aos terrenos Riacianos do Cráton Oeste-Africano. O depósito se formou após o metamorfismo regional (estimado em 2100 ± 15 Ma) e está hospedado em zona de cisalhamento que secciona xistos do Grupo Aurizona (2240 ± 5 Ma) e o Microtonalito Caxias. O microtonalito foi aqui datado em 2009 ± 11 Ma, e representa um estágio magmático tardio na evolução do fragmento cratônico São Luís. Cristais de zircão com idades de 2139 ± 10 Ma foram herdados da fonte magmática ou são produto de contaminação durante a intrusão. A composição dos isótopos de chumbo sugere que granitoides de arco de ilhas de ca. 2160 Ma são a fonte provável para o Pb incorporado na pirita relacionada com o minério. Sericita hidrotermal mostra idade 40Ar/39Ar de 1990 ± 30 Ma, que, combinada com a idade de posicionamento do microtonalito hospedeiro, limita o evento mineralizador ao intervalo 2020-1960 Ma.

The Crixas Greenstone Belt is a supracrustal rock sequence of the allochthonous Archean-Paleoproterozoic Crixas-Goias Terrane of the Neoproterozoic Tocantins Province of Central Brazil. The belt occurs between Mesoarchean (2.9-2.8 Ga) primitive orthogneiss complexes intruded by Siderian intracratonic mafic dikes and stocks. The rock succession of the greenstone belt consists of metakomatiites followed by metabasalts, both of greenschist to low amphibolite facies, underlying metasedimentary rocks of low greenschist facies. The greenstone belt is divided into the southern, central, and northwestern sectors, with different rock associations. The northwestern sector tectonically underlies a small exotic block known as the Mina Inglesa Sequence. The sequence consists of a low greenschist facies volcano-sedimentary package similar to a greenstone belt, but of unknown origin. The latest stratigraphic nomenclature for the belt labels its rock package as the Crixas Group. From base to top, the Group comprises the Corrego Alagadinho, Rio Vermelho, and Ribeirao das Antas Formations, made up of metakomatiites, metabasalts, and metasedimentary rock, respectively. The Mina Inglesa Sequence is an independent unit of the Crixas Group, in spite of the similar rock assemblage of both units. Protoliths of the Ribeirao das Antas Formation comprise shallow water black shales with dolomite lenses, laterally wedge-shaped with impure turbiditic sandstones (wakes). Published U/Pb and Sm/Nd whole-rock isotopic data indicate that the metakomatiites and metabasalts erupted during the Mesoarchean (3.0 Ga). Detrital zircon grains from the sedimentary protoliths suggest a mixed Mesoarchean and Rhyacian source-area (3.2 and 2.2 Ga). The U/Pb age from hydrothermal zircon grains of a gold-bearing quartz vein indicates that the sedimentation ended just before 2.1 Ga. Field, drilling, and the isotopic data led the authors to review the stratigraphic content of the Crixas Group by subdividing it into an Upper and Lower Subgroups. The Lower Subgroup comprises the Mesoarchean volcanic section subdivided, from base to top, into the currently adopted Corrego Alagadinho and Rio Vermelho Formations. The Upper Subgroup rests ubnconformable on the Lower Subgroup, and comprisess the Rhyacian metasedimentary section. The Upper Subgroup contains two rock units deposited in different environments. The currently used Ribeirao das Antas Formation is the lower unit, which is redefined as composed of carbonaceous phyllites with dolomite lenses. The upper unit comprises the new proposed Corrego Geral Formation, composed of metagraywackes. The wedge-shaped contact between both sedimentary units indicates that they were coevally deposited. The Paleoproterozoic sedimentary basin consisted of a small depression formed during the sagduction of the volcanic pile, triggered by the diapiric rise of the adjacent orthogneiss protoliths. The sediment deposition started with black shales in response to a slow rise of the seawater and paleoclimatic conditions. An increasing input of siliciclastic turbidites occurred in response to the uplift of a Rhyacian/Mesoarchean source-area that provided a mixed clastic load. Anomalous positive δ13C data from the dolomite lenses indicate that they deposited during the 2.2-2.1 Ga Lomagundi Event, which is compatible with the dominant Rhyacian zircon grains of the graywackes. The Crixas-Goias Terrane lacks geologic evidence for the existence of an internal Rhyacian crustal block to justify the youngest detrital zircon grains of the graywackes. These observations render uncertainty about the geographic position of the rising crust. Paleoproterozoic crustal shortening of the belt resulted in stacked thin-skinned thrust-faults that host gold orebodies. An eastward age decrease of the crustal shortening from Crixas to an easterly belt leads the authors to propose that the clastic load source could occur to the West of the Terrane. The Mina Inglesa Sequence is an allochthonous block with lithologic and isotopic features that distinguish it from the greenstone belt. The authors also describe that there is no isotopic evidence for Meso- to Neoproterozoic source-areas, neither for the Corrego Geral Formation nor for the Mina Inglesa Sequence. These findings raise a suggestion that the granite-greenstone belt association of the Terrane may represent a craton border that remained stable before its amalgamation to the province during the Neoproterozoic.

The Mn-bearing Buritirama Formation along the homonymous ridge consists of a 40 km long by ca. 3 km wide NW-SE trending unit that limits the northern border of the Archean Carajas domain with the Paleoproterozoic Bacaja domain in the southeastern Amazon Craton. The Buritirama Formation type section is arranged in four imbricated thrusts that individualize three main stratigraphic units: Lower Unit, Intermediate Unit and Upper Unit. Detrital U-Pb zircons ages from the Lower Unit and Upper Unit record the prevalence of Neoarchean populations, suggesting the Carajas block as the main sedimentary source for the Buritirama basin. However, minor Paleoproterozoic populations attributed to the Bacaja block are also recognized, defining a maximum depositional age at ca. 2186 Ma. The anorogenic Buritirama metagranite occurs at the local basement, represents a probable precursor stage of the Buritirama rift and yielded a Concordia age of 2549 ± 5.9 Ma (U-Pb). Supported by these new geochronological data, a framework model for the evolution of the Buritirama basin is proposed. Contrary to previous interpretations, the basin was active until at least the Rhyacian, representing a platformal setting fringing the northern margin of the Carajas block. A regional metamorphic event (ca. 2.06 Ga) records the closure of the basin during the Transamazonian Orogeny and the amalgamation of the Bacaja and Carajas blocks. The depositional age bracketed in between 2.3 and 2.1 Ga links the Buritirama Mn deposit (southeastern Amazon Craton) with those of Serra do Navio (Amapa Block, northeastern Amazon Craton) and Nsuta (West African Craton), suggesting: (i) widespread chronocorrelation of Mn-bearing sequences in the continental-scale Rhyacian Transamazonian/Birimian orogenic system, and (ii) formation of the primary carbonate ores under the influence of a major global manganese deposition episode.

The Estreito Anticline is the main structure in the northwestern sector of Passos Nappe, formed in the Late Neoproterozoic during West Gondwana amalgamation. It is characterized by folding of the thrust surface that separates the Passos Nappe from the Canastra Group. The hanging wall of the thrust includes lower units of the Passos Nappe (A, B and C units) and in the core of the fold (footwall) occur metasedimentary rocks of the Canastra Group and Metasiltite Unit. U-Pb dating of detrital zircon grains by LA-ICPMS from metasedimentary units of the Canastra Group shows contribution from a Neoarchean source (ca. 2.54–2.76 Ga) with minor contribution from Rhyacian source ( ∼ 2.10–2.30 Ga) with the youngest grain at 1.57 Ga. Results from the Passos Nappe samples show an important Rhyacian source (2.1 Ga), and a minor cluster with ages ranging from ca. 1.60 to 1.76 Ga (Statherian). Mesoarchean- Statherian terranes of the southwest margin of the Sao Francisco Craton represent the main sources of detrital sediments of the Passos Nappe and Canastra Group of a passive margin developed along the western margin of the continent. The U-Pb ages obtained for metasiltite show a broad distribution, with peaks between ∼ 0.54-0.70 Ga, and minor age groups ranging within 0.82–1.08 Ga, 1.60–1.97 Ga, 2.02–2.22 Ga and ∼ 2.60–2.85 Ga. The younger ages are compatible with the Bambui Group exposed in the Sao Francisco Craton interior. An Ediacaran age for metasiltite in the fold interior suggests termination of deformation within the Passos Nappe at least the Early Cambrian.

Accretionary orogens are considered as the result of the major crust production process, and terranes are accreted material representing distinctive assemblages regarding age and evolution. Scientific advances in the last years show that the southernmost Sao Francisco Craton includes Archean, Paleoproterozoic and Neoproterozoic areas. We used aerogeophysical data and field geology to understand the extension of individual pieces of this tectonic puzzle. We described five magnetometric lineaments. A–, B– and C–lineaments are related to dyke swarms of different ages. D– and E–lineaments represent regional-scale tectonic structures. In a tectonic perspective, we have identified the following terranes: (i) the Archean Sao Tiago crust (2.67 Ga), which is part of the Sao Francisco proto-craton; two Siderian juvenile arcs, represented by the (ii) Cassiterita (2.47 Ga) and the (iii) Resende Costa/Lagoa Dourada (2.36–2.35 Ga) orthogneisses; and two Rhyacian arcs, the (iv) juvenile Serrinha (2.22–2.20 Ga) and the continental Ritapolis (2.19–2.10 Ga) arcs. Tectonic terranes and five magnetic subdomains were identified on the basis of (i) association of shear zones/faults with quartz veins in the field; (ii) low– and high–intensity magnetic anomalies; (iii) sharp contrast in Euler solution intensities; and (iv) high–contrast in radioelement contents in the gammaspectrometric maps. Processing of aerogeophysical data permitted us to propose a new scenario on the evolution of the southern Sao Francisco Craton, and in particular of the Mineiro belt. The integration between aerogeophysical, new and compiled geologic information, provides a robust model for the understanding of individual tectonic pieces of the studied area.

Combined LA-ICP-MS and SHRIMP U–Pb ages from Quadrilatero Ferrifero (QF) province reveals for the first time three main periods of TTG magmatism in the southern part of the Sao Francisco Craton (Brazil). These periods – described here as the Santa Barbara (SB), Rio das Velhas I (RVI) and Rio das Velhas II (RVII) events – embody a significant part of a protracted tectonomagmatic history of the Craton, spanning from 3220 to 2770 Ma. The initial stages of TTG magmatism (the SB event) led to formation of a core of Palaeoarchaean TTG crust via magmatic additions of juvenile felsic rocks into mafic–ultramafic rocks, at ca. 3212–3210 Ma. The following event (RVI event) saw the growth of this Palaeoarchaean core into a more composite, polydefomed continental segment through magmatic additions of juvenile TTG rocks and tectonic accretion of mafic–ultramafic greenstone belt terrains. Our U–Pb data and regional constraints suggest that much of the TTG crust exposed in the QF region today was produced during the RVI event, between 2930 and 2900 Ma. The final stages of TTG crust production (RV II event) were marked by convergence-related magmatism, affecting an extensive Palaeo- to Mesoarchaean continental block (The RVI block). The timing and duration of the latest TTG event coincides with the felsic volcanism and deposition of turbiditic wackes of the main greenstone belt sequence.

The Serra das Araras Batholith (SAB), located at the southwest portion of the Paraiba do Sul Domain, Central Ribeira Belt, is composed of orthogneisses with peraluminous character. Combined LA-ICP-MS U-Pb and Lu-Hf isotopic analyses have been performed in zircon grains for a representative sample (SA-3H) of SAB. Data point to Rhyacian to Orosirian ( ca . 2.1–1.8 Ga) inherited zircon cores with positive ɛHf (t) values and Ediacaran U-Pb crystallization age (595 ± 8 Ma). A leucogranite dyke (SA-3D), 15–25 cm thick, which crosscuts SAB and a biotite-hornblende quartz diorite enclave (SA-06) have been analyzed. Crystallization ages for the three samples ( ca . 600-590 Ma) and ɛHf (t) values, ranging from −5.6 to −29.4 for Neoproterozoic zircon grains, indicate an Ediacaran crustal magmatism involving mid to lower crust anatexis and the reworking of Paleoproterozoic juvenile and crustal rocks.

Located in central Minas Gerais state, the Mineiro belt and the adjacent mining district known as the Quadrilatero Ferrifero (QF) represent segments of a Paleoproterozoic orogen preserved in the southern Sao Francisco craton. Siderian to Rhyacian juvenile granitoids associated with volcanic and sedimentary rocks are the main rock assemblages involved in the evolution of the Mineiro belt. The plutonic rocks characterize four distinct groups of subduction-related granitoids generated between 2.47 and 2.10 Ga. The supracrustal units comprise four volcano-sedimentary successions deposited in island arc settings during the same age interval of the granitoids. The structural picture of the Mineiro belt is dominated by NE-trending oblique to strike-slip shear zones associated to a regionally penetrative SE-dipping foliation. The Paleoproterozoic rock record of the QF includes greenschist to amphibolite facies metasedimentary successions, which unconformably overlie a Meso- to Neo-archean granite-greenstone basement assemblage. The Minas Supergroup comprises passive margin and syn-orogenic sediments, deposited during the 2.58–2.42 Ga interval and around 2.10 Ga, respectively. The youngest Paleoproterozoic unit of the QF, the Itacolomi Group, comprises post-orogenic intermontane deposits, accumulated between 2.05 and 1.74 Ga. The large-scale structures of the QF, an association of basement domes and synclines containing the Paleoproterozoic units, characterize a typical dome-and-keel architecture, whose development at around 2.05 Ga was preceded and followed by contractional deformation events. As components of a Paleoproterozoic orogen that also encompasses the Eastern Bahia orogenic domain of the northern portion of the craton and its African counterpart, the Mineiro belt and the QF are presently viewed respectively as an intra-oceanic arc system and a continental margin basin, which interacted and collided during the transition between the Rhyacian and Orosirian periods.

The Paleoproterozoic Eastern Bahia orogenic domain occupies an approximately 200 km-wide area in the northern Sao Francisco craton, located between the Atlantic coast and the interior plateau of Bahia state known as the Chapada Diamantina. Together with its African counterpart, the West Central African belt of Gabon, the Eastern Bahia orogenic domain form a complete segment of a collisional orogen developed during the transition between the Rhyacian and Orosirian periods. Exposed in the level of its roots, the Eastern Bahia orogenic domain involves mainly amphibolite to granulite facies rocks that characterize three distinct Archean basement blocks (the Gaviao, Jequie and Serrinha blocks) and a Neoarchean magmatic arc (the Itabuna-Salvador-Curaca belt, ISAC belt). The Paleoproterozoic rock record of the domain includes volcanic, sedimentary and granitic assemblages deposited and emplaced during its pre-, syn- and post-collisional evolutionary stages. The supracrustal rocks are represented by continental to marine metasedimentary successions of presumed Siderian to Rhyacian ages, as well as volcano-sedimentary accumulated in intra- and back-arc basins settings. The granitic rocks comprise five distinct groups of relatively small plutons emplaced between 2320 and 1960 Ma, mainly in the Gaviao and Serrinha blocks. The structural framework of the domain involves sinuous NS-trending and E-dipping reverse, reverse-sinistral to sinistral strike-slip faults and ductile shear zones. These structures nucleated during a second and syn-metamorphic deformation phase dated at ca. 2080 Ma, which was preceded by the convergence and collision of the various basement blocks of the domain at around 2100 Ma. This chapter contains a synthesis on the stratigraphy, overall structure and Paleoproterozoic evolutionary history of the domain.