Abstract The Atuba Complex occurs in the eastern region of Paraná State, located in the Southern Ribeira Belt. It is comprised of the Curitiba Terrane, northward of the Luís Alves Terrane, and southward of the Apiaí Terrane. This research was carried out by means of detailed petrography, microtectonics, and brittle and ductile structural analysis. The Atuba Complex is composed of migmatites, felsic granulites, granitoids, quartzites, phyllonites, schists, amphibolites, and cataclasites. The lithotypes are cut by diabase or gabbro dikes, lamprophyre dikes, pseudotachylites, and quartz, epidote, carbonate, or chlorite veins. The migmatites are characterized by two migmatization phases, the first composed of tonalitic leucosomes and the second formed by granitic leucosomes. The stromatic and mylonitized migmatites suggest dislocation creep mechanisms and dynamic recrystallization processes, mainly in quartz and feldspars. During the initial phase, melting reactions took place through dehydration, while in the subsequent phase, melting was facilitated by the presence of water-fluxed. The Atuba Complex comprises two foliations, Sn-1 (Dn-1 phase) and Sn (Dn phase). The Sn-1 surface (compositional banding) presents a ductile and anastomosed aspect with an N45W/55NE attitude, whereas the Sn mylonitic foliation is defined by the presence of mineral flattening or stretching and by the orientation of amphibole and biotite shapes, with a maximum plane of N45E/85NW. The observed faults and fractures strike in the NE-SW and NW-SE main directions. The paleostress study provided the recognition of a NE-SW sigma 1 associated with a NW-SE-striking sigma 3 for the left-lateral strike-slip faults and an E-W compressive SHMAX and an N-S distensive SHMIN for the right-lateral strike-slip faults. State Belt Terrane petrography microtectonics analysis granulites granitoids quartzites phyllonites schists amphibolites cataclasites dikes pseudotachylites epidote carbonate veins phases processes feldspars phase dehydration waterfluxed. waterfluxed water fluxed. fluxed water-fluxed foliations Sn1 Sn- Dn1 Dn (Dn- phase. . compositional banding N45W55NE NWNE N45W 55NE N W NE attitude shapes N45E85NW NENW N45E 85NW E NW N45E/85NW NESW SW NWSE SE directions NWSEstriking striking leftlateral left lateral strikeslip slip EW NS S rightlateral right

Abstract This research aims to obtain tomographic images to interpret the seismic stratigraphic profile around the San Rafael (SR) knickpoint using seismic tomography. The SR waterfall on the Coca River sinkhole in February 2020 caused regressive soil erosion, suggesting that the knickpoint is highly unstable. Seismic tomography for the P-wave velocity model, utilizing data from 14 stations in the permanent Ecuadorian seismic network, produced vertical cross-sections at azimuths of 0°, 45°, 90°, and 80°. These sections reveal geological formations and their transition to volcanic deposits, while a horizontal cross-section illustrates the extent of the volcanic deposits. The tomographic images facilitated the identification and correlation of seismic stratigraphy with the area's geological features. The most unstable materials for erosion lie from 0 km to 1.5 km with velocities of up to 3.5 km/s. The erosive process impacts the population and infrastructure settled on the banks of the Coca River with a high susceptibility to erosion in zone 1, with velocities of 3 km/s and a 10 km extension. The Coca Codo Sinclair Dam (CCSD) is located in zone 2, with velocities of 3.8 km/s extending up to 40 km with medium susceptibility to erosion. (SR 202 Pwave P wave model 1 network crosssections cross 0° 45 45° 90 90° 80 80° deposits crosssection section areas area s features 15 5 1. 35 3. kms extension CCSD (CCSD 2 38 8 4 20 9

Abstract We combined detailed field work with whole-rock geochemistry of samples from both surface exposures and rock chips from a ~300 m pile of basalt retrieved from a groundwater borehole in the Jaú region (central part of the state of São Paulo) to contribute to the stratigraphic knowledge of the northern Paraná Magmatic Province. The P2O5 content was used as the first guide to flow identification, always combined with other minor and trace elements (mostly Ti, Zr, Sr, and Cu). This approach allowed the establishment of a stratigraphic column with 16 flows, which were tentatively divided into three sequences. Regional correlations show that the lower portion of these basalt flows (Sequence 1) has good correspondence with the flow-by-flow succession identified at the border of the Paraná Basin by previous regional works. The upper eight flows, occurring at the top of the plateau where the thickness of basalt reaches up to 300 m, should have their continuity westward (toward the center of the Paraná Basin), where the volcanic pile thickens. The local preservation of these upper flows may result from significant (up to 170 m) displacements along the ENE-directed Jaú fault, identified from stratigraphic relations here defined in the basalt pile. wholerock whole ~30 central Paulo Province PO P O P2O identification mostly Ti Zr Sr Cu. Cu . Cu) 1 sequences Sequence flowbyflow works 30 toward Basin, , Basin) thickens 17 ENEdirected ENE directed fault ~3 3 ~

Abstract The Cachoeirinha Sn ± (Nb-Ta) deposit is an important producer of the Rondônia Tin Province. It is inserted in the regional unit named Rondônia Intrusive Suite (995–956 Ma) and hosts granular accumulations of columbite group minerals (CGM) embedded in thick Cenozoic colluvial-alluvial covers. Cachoeirinha CGM have subrounded to angular grains, with irregular to regular internal zoning, micro-inclusion, and exsolution features. They have columbite-(Fe) as the dominant mineral phase, with variation in the Ta/(Ta+Nb) ratio and with Sn, Ti, W, U, Ba, Cr, REE, and V as chemical impurities. It has high total REE content (LREEN depleted, HREEN enriched, Ce and Eu anomalies), δ18O = 2.78‰, and with two U-Pb age groups: 1052 ± 6 and 909 ± 7 Ma. This information indicates that physicochemical oscillations favored the ionic substitutions and resorption mechanisms between Nb ↔ Ta, as well as coupled substitutions with the entry of geochemical impurities, according to the equation: 3(Sn, Ti, U, Si)4+ + (W, Cr)6+ ↔ 2(V, Nb, Ta)5+ + 2(Al, REE)3+ + (Fe, Mn, Ba)2+, at the temperature range between 400° and 500°C. Finally, the Cachoeirinha Sn ± (Nb-Ta) alluvial deposit host ore is related to at least two Neo-Mesoproterozoic magmatic pulses. NbTa Ta (Nb-Ta Province 995–956 995956 995 956 (995–95 Ma (CGM colluvialalluvial colluvial covers grains zoning microinclusion, microinclusion micro inclusion, inclusion micro-inclusion features columbiteFe Fe columbite-(Fe phase Ta/Ta+Nb TaTaNb Ta/ Ta+Nb Ta/(Ta+Nb Ti W U Ba Cr impurities LREEN depleted enriched anomalies, anomalies , anomalies) δO δ O 278 2 78 2.78‰ UPb Pb groups 105 90 equation 3Sn, 3Sn 3 3(Sn Si4+ Si4 Si 4+ 4 Si)4 (W Cr6+ Cr6 6+ Cr)6 2V, 2V V, 2(V Ta5+ Ta5 5+ 5 Ta)5 2Al, 2Al Al Al, 2(Al REE3+ REE3 3+ REE)3 Fe, (Fe Mn Ba2+, Ba2 2+, Ba)2+ 400 500C C 500 500°C Finally NeoMesoproterozoic Neo Mesoproterozoic pulses 995–95 99595 99 95 (995–9 TaNb 27 2.78 10 9 Si) Cr) Ta) REE) Ba2+ 2+ Ba)2 40 50 995–9 9959 (995– 2.7 1 Ba) 995– (995 2. (99 (9 (

Abstract Mass movements naturally occurring along slopes, especially after heavy rains, cause heavy losses of materials and life and affect highways, pipelines, and bridges, among other structures. Among the most common mass movements, landslides and subsequent mass flows especially stand out. Remote sensing and geoprocessing techniques are useful tools for geological and geotechnical analysis, here applied to characterization of mass movements from the analysis of the influence of slopes, lineaments or fractures, and geological-geotechnical at the junction of the Curral homocline and the Moeda syncline, Quadrilátero Ferrífero, Southeast Brazil. The area consists of Archean granitic-gneissic basement and the greenstone belt sequence of the Rio das Velhas Supergroup with Proterozoic metasedimentary rocks of the Minas Supergroup covering these two older successions. Based on satellite images, a preliminary map of lineaments was created, and fractures were grouped according to their direction before being rasterized. Each lineament group was associated with a previously known geological and/or structural feature. Geological units mapped in the area were numerically classified according to their mass movement susceptibility and related geotechnical units. Using a Shuttle Radar Topography Mission (SRTM) image, a terrain slope raster was generated. The objective was to obtain a raster indicating low and high probabilities of mass movements. Four sets of lineaments were identified: the first set associated with the northeast strike stratification of the rocks of the Moeda Formation; the second set related to eastward-trending warp axis lineations; the third set related to the southeast trend of stretch lineaments or mafic dykes directions; and the fourth set evidently associated with the watershed pattern of the Curral Range crest, perpendicular to the strike of the rocks in the area. Simulations with different combinations of parameters produced eight scenarios were generated were constructed to classify the area as to its susceptibility to rupture through changes in slope, lithotype, and lineament density; the first four (1 to 4) were classified by using the slope percentage raster without interval reclassification, so its values in the cartographic algebra were not grouped. The last for (5 to 8), consider the slope percentage classified. This methodology successfully combines mathematical models for predicting mass movements and determining areas in the urban landscape most susceptible to these phenomena. As such, it comprises a useful tool for government planning of preventative actions for areas of high risk. slopes rains highways pipelines bridges structures out geologicalgeotechnical syncline Ferrífero Brazil graniticgneissic granitic gneissic successions images created rasterized andor feature SRTM (SRTM image identified Formation eastwardtrending eastward trending lineations directions crest lithotype density 1 ( 4 reclassification 5 8, 8 , 8) phenomena such risk

Abstract The Rio dos Remédios Group comprises a supracrustal sequence that occupies the base of the Espinhaço Supergroup, São Francisco Craton, Brazil. Its basal formation, Novo Horizonte, crops out in the Paramirim region mainly as metavolcanic rocks that represent one of the fewer occurrences of blue quartz phenocrysts in South America. Their mineralogy consists of quartz and K-feldspar phenocrysts, whereas biotite, muscovite, fluorite, allanite, chlorite, sericite, zircon, and opaque phases occur immersed in a quartz-feldspar-rich groundmass. Such heterogeneous composition is also supported by x-ray diffraction and chemical data. Electron probe microanalysis in some samples revealed the presence of two distinct groups of biotite (magmatic and neoformed), in addition to the presence of iron-rich white mica and almost pure orthoclase feldspar. Our data suggest that the studied metavolcanic rocks have maintained their magmatic characteristics, which were progressively overprinted by hydrothermal fluids and ductile-to-brittle deformation. The magmatic mineralogy is akin to strongly peraluminous and alkaline magmas, common in anorogenic settings – a fertile site for the origin of blue quartz-bearing rocks worldwide. Supergroup Craton Brazil formation Horizonte America Kfeldspar K feldspar muscovite fluorite allanite chlorite sericite zircon quartzfeldsparrich rich groundmass xray x ray neoformed, neoformed , neoformed) ironrich iron characteristics ductiletobrittle ductile brittle deformation magmas quartzbearing bearing worldwide

Abstract Central Brazil hosts Paleo-Mesoproterozoic A-type granitic suites related to the Goiás Tin Province (GTP) that contain Sn (±W, Nb-Ta, REE) mineralization associated with greisen, veins, and small pegmatite bodies. The Pedra Branca granite massif (1.77–1.74 Ga) is the main representative of GTP, marked by important cassiterite (±wolframite) contents. The cassiterite contains SnO2= 96–100 wt. %, with the sum FeOtotal, TiO2, WO3, Ta2O5, Nb2O5, In2O3, and UO2 content below 4 wt.%, while wolframite contains WO3= 71.5–74.5 wt.%, FeOtotal= 14.3–17.4 wt.% and MnO = 6.3–9.9 wt.%, as well as Sn, Ca, Ti, Ta, Nb, Pb, In, and U as trace elements. The δ18O data on the quartz-cassiterite pair (quartz = 9.4–10.4‰, cassiterite = 2.6–2.9 ‰) from greisen reveal a magmatic-hydrothermal signature with calculated crystallization temperatures between 410 and 485°C. However, during the Neoproterozoic Brasiliano/Pan-African Orogeny (800–500 Ma), all lithologies and ore sites were subjected to flattening, fragmentation, and mylonitic deformation. Fluid inclusion data revealed the presence of low-salinity aqueous solutions with homogenization temperatures between 215 and 100°C related to Neoproterozoic deformation. Finally, during the Phanerozoic, prolonged erosive produced Sn (±W)-rich alluvium around the Pedra Branca granitic massif. PaleoMesoproterozoic Paleo Mesoproterozoic Atype A type GTP (GTP ±W, W (±W NbTa, NbTa Nb Ta Nb-Ta REE veins bodies 1.77–1.74 177174 1 77 74 (1.77–1.7 Ga ±wolframite (±wolframite contents SnO2 SnO 96100 96 100 96–10 wt % FeOtotal TiO2 TiO WO3 WO Ta2O5 TaO O Nb2O5 NbO In2O3 InO In UO 715745 71 5 71.5–74. 143174 14 3 17 14.3–17. 6399 6 9 6.3–9. Ca Ti Pb elements δO δ quartzcassiterite quartz 94104 10 9.4–10.4‰ 2629 2 2.6–2. ‰ magmatichydrothermal magmatic hydrothermal 41 485C C 485 485°C However Brasiliano/PanAfrican BrasilianoPanAfrican Brasiliano/Pan African Brasiliano Pan 800–500 800500 800 500 (800–50 Ma, Ma , Ma) flattening fragmentation deformation lowsalinity low salinity 21 100C Finally Phanerozoic ±Wrich Wrich ±W rich 1.77–1.7 17717 7 (1.77–1. 9610 96–1 Ta2O Nb2O In2O 71574 71.5–74 14317 14.3–17 639 6.3–9 9410 9.4–10.4 262 2.6–2 48 PanAfrican BrasilianoPan 800–50 80050 80 50 (800–5 1.77–1. 1771 (1.77–1 961 96– 7157 71.5–7 1431 14.3–1 63 6.3– 941 9.4–10. 26 2.6– 800–5 8005 8 (800– 1.77–1 177 (1.77– 715 71.5– 143 14.3– 6.3 94 9.4–10 2.6 800– (800 1.77– (1.77 71.5 14.3 6. 9.4–1 2. (80 1.77 (1.7 71. 14. 9.4– (8 1.7 (1. 9.4 ( 1. (1 9.

Abstract The Geological Strength Index (GSI) system is the basis of parameters used in the Hoek-Brown failure criterion for rock mass strength estimation. The author tested this system and here suggests a modified GSI called Geological Strength Index-slope (GSIslope). The modified system combines two different existing approaches: the GSI system and Slope Mass Rating (SMR). The purpose of GSIslope is to allow engineering geologists to quickly evaluate the stability of natural and excavated slopes or open-pit mining in the field. GSIslope is computed by subtracting a constant value of 10 and the multiplication of adjustment factors for discontinuity orientation and slope (F1, F2, and F3, based on the parallelism of discontinuity and slope, discontinuity dip angle, and the difference between the inclination angle of discontinuity and slope) from GSI, and adding field groundwater rating to it. Modified curves are also proposed in this work to determine the accurate ratings of the adjustment factors. The results of this work are compared to the values obtained from equations of continuous-SMR and SMR-value itself for both the adjustment factors and GSIslope values. The comparison showed that the proposed curves and GSIslope equation are valid and easy to use for estimating the adjustment factors’ ratings and GSIslope value. (GSI HoekBrown Hoek Brown estimation Indexslope GSIslope. . (GSIslope) approaches SMR. SMR (SMR) openpit open pit 1 F1, F1 F (F1 F2 F3 it continuousSMR continuous SMRvalue (GSIslope (SMR (F

Abstract Sinter overlying the first quartz andesite flow at the base of the Serra Geral Group is a surface manifestation of intense hydrothermal processes operating in the Paraná Basin during the Early Cretaceous. The coarse quartz sinter from western Rio Grande do Sul state was studied in satellite images, field surveying, optical petrography, scanning electron microscopy, and electron probe microanalyses, including backscattered electron images and chemical analyses of rocks. Quartz forms large crystals (10 cm) because it was either deposited in a dilute aqueous solution or recrystallized from fine-grained sinter. Well-crystallized chamosite — an iron aluminosilicate (Fe-chlorite) — occurs in quartz crystals, partly associated with fractures. The composition of chamosite is akin to that in ore deposit associations. Noble metals in two sinter samples are present in concentrations of 0.1 ppm Ag and 15 ppb Au. The contents of Ba, Bi, Cu, Mo, S, and W are low but are significant. The present description of sinter quartz signals the presence of a major paleo-hotspring field in the Fronteira Oeste Rift, Rio Grande do Sul, Brazil, that mertis further study to fully characterize the extent and metallogenetic endowment (Au-Ag-Cu) of the epithermal province. Cretaceous surveying petrography microscopy microanalyses rocks 10 (1 cm finegrained fine grained Wellcrystallized Well crystallized Fechlorite Fe chlorite (Fe-chlorite fractures associations 01 0 1 0. Au Ba Bi Cu Mo S significant paleohotspring paleo hotspring Rift Brazil AuAgCu (Au-Ag-Cu province (

Abstract Seismic data, borehole image logs, and conventional well logs were used to investigate the distribution and characteristics of paleokarst features in the Aptian carbonates of the Barra Velha Formation in a pilot area of the Santos Basin, Brazil. Multiple seismic attributes were used to enhance details on the seismic data and highlight key seismic parameters including strata deformation and geometry, continuity of seismic events, and fault patterns. The study found that karst structures are controlled by faults and fractures along structural highs, which served as a conduit for the flow of dynamic fluids that dissolved the carbonate materials. Several closed, circular depressions and bright spots identified in the northeastern portion of the study area represent possible sinkhole structures. Epigenic and hypogenic processes due to the action of meteoric water, hydrothermal activity, and intra-formation acidity along regional unconformities in the Barremian-Aptian may have been responsible for the dissolution. Limitations of this study are related to the difficulty of integrating multiple datasets with various scales. However, the higher confidence for the occurrence of the karst features is provided by borehole images at the sub-seismic scale. The findings of this study hold significant relevance for the strategic planning of energy development and carbon sequestration initiatives in the Brazilian continental margins, thereby aiding in informed decision-making. Basin Brazil geometry events patterns highs materials closed water activity intraformation intra formation BarremianAptian Barremian dissolution scales However subseismic sub scale margins decisionmaking. decisionmaking decision making. making decision-making

Abstract Benthic foraminifera, ostracods and pteropods are reliable paleoenvironmental indicators in Quaternary deposits. However, in the Ceará Basin, on the Brazilian Equatorial Margin, these microfossils are poorly studied. This paper investigates environmental changes during the Pleistocene–Holocene transition in the Icaraí subbasin based on micropaleontological analysis of the core ANP 1011. Seventy-four taxa of benthic foraminifera, represented predominantly by Globocassidulina, Uvigerina, Pyrgo and Melonis, have been identified. The ostracod assemblages are composed mainly by the families Macrocyprididae, Cytheruridae, Trachyleberididae, Pontocyprididae and Krithidae, of which the genus Krithe was the most abundant. The composition of the ostracod assemblages identified in this study area differs somewhat from other regions of the Brazilian Margin. The assemblages of foraminifera and ostracod characterize a typical bathyal paleoenvironment. The occurrence of pteropods and dominance of epifaunal foraminifera taxa, mainly Pyrgo sp. and Miliolinella sp. in the lower portion of the core (Pleistocene), indicates higher phytodetritus input and oxygen concentration. A conspicuous environmental change was observed in the upper portion of the core, which corresponds to the Holocene, where the increase of infaunal foraminifera (e.g., Uvigerina, Globocassidulina and Melonis) suggests reduction in the organic matter input and, probably, increased bacterial density and depletion in dissolved oxygen in the sediment. deposits However Basin Margin studied PleistoceneHolocene Pleistocene Holocene 1011 Seventyfour Seventy four Uvigerina Melonis Macrocyprididae Cytheruridae Trachyleberididae Krithidae abundant paleoenvironment sp Pleistocene, , (Pleistocene) concentration e.g., eg e g (e.g. probably sediment 101 (Pleistocene e.g. (e.g 10 e.g 1

Abstract Disarticulated shells of three bivalve mollusk species (Anomalocardia brasiliana, Codakia orbicularis, and Divaricella quadrisulcata) were experimentally tested in laboratory flumes to determine the threshold of motion and final orientation of the valves. A total of 150 current flow experiments were conducted on single shells resting on a fixed sand bed. This study demonstrated that shells in the convex-up position are more resistant to flow when the umbo is pointing downstream rather than upstream. Moreover, species with higher frontal areas were more likely to be entrained at lower flow velocities. Results of dimensionless shear stress exhibited values far below the threshold of grains movement for beds of uniform roughness (Shields curve). It was observed that circular shells in convex-up positions were mostly orientated with the umbo pointing downstream. Conversely, elliptical shells in convex-up position tended to align their longer axis parallel to the flow with the posterior side of the valve pointing downstream. These results are not only directly applicable in interpretations of incipient shell motions and in paleocurrent analyses from field and sample data, but also support construction of accurate geological models. Anomalocardia brasiliana orbicularis quadrisulcata valves 15 bed convexup convex up upstream Moreover velocities Shields curve. curve . curve) Conversely data models 1

Abstract Alkaline dikes from the Santos-Rio de Janeiro coast, SE Brazil, mainly from São Sebastião and Búzios islands, yielded a Late Cretaceous paleomagnetic pole (SR) located at 319.7°E 81.2°S (N = 44, A95 = 3.0°, k = 44). This pole includes some sites of alkaline stocks from São Sebastião Island of the same age and supersedes the previous pole for this island. To match the available radiometric ages and the prevailing normal polarity remanence of the rocks with the geomagnetic polarity time scale, the SR pole is placed at 84 Myr. Another group of alkaline rocks, dikes located mainly in Rio de Janeiro, was assigned an age of less than 70 Myr. The ages of the Poços de Caldas, Itatiaia, and Passa Quatro paleomagnetic poles are also discussed based on available radiometric data. Assuming a rigid plate, the SR pole indicates the southward movement of about 7° with virtually no rotation between 100 and 84 Myr. From approximately 84 to 70 Myr, a clockwise rotation of 8° is postulated, with slight variation in latitude. SantosRio Santos coast Brazil islands (SR 3197E E 319 7 812S S 81 2 N 44 A A9 30 3 0 3.0° 44. . 44) island scale 8 Myr Caldas Itatiaia data plate 10 postulated latitude 31 4 3.0 1 3.

Abstract The Bacajá domain, southeastern Amazonian craton, comprises Mesoarchaean and Siderian terrains reworked during the Transamazonian cycle. Combined analyses of zircon LA-ICP-MS U-Pb and Lu-Hf with whole-rock Sm-Nd from the northeast portion of this domain made it possible to propose an evolutionary sequence between ca. 2.60 and 2.06 Ga. Gneisses with an igneous protolith age of 2630±15 Ma show negative signatures (ɛHft = -0.3 to -1.7 and ɛNdt = -3.08 to -2.98) and a Mesoarchaean formation (Hf-TDMC and Nd-TDM model ages range from 3.0 to 3.2 Ga). Rhyacian granite genesis lasted about 40 million years (2.10–2.06 Ga) and was divided into two magmatic periods. The first is represented by deformed granitoids with zircons yielding crystallization ages between 2.10 and 2.09 Ga and model ages (Hf-Nd) at about 2.5 Ga. The second event is represented by granitoids with preserved magmatic texture, crystallization ages of 2.06 Ga, and Siderian model ages (Hf-Nd) of around 2.3 Ga. The overall Hf isotopic analyses of this Rhyacian granite genesis exhibit a spread of ɛHft values between 1.8 and -2.9, which show a probably underestimated mantle-derived contribution in this period. craton cycle LAICPMS LA ICP MS UPb U Pb LuHf Lu wholerock whole rock SmNd Sm Nd ca 260 2 60 2.6 206 06 2.0 263015 2630 15 2630±1 0.3 03 0 3 -0. 1.7 17 1 7 -1. 3.08 308 08 -3.0 2.98 298 98 -2.98 HfTDMC TDMC NdTDM TDM 30 3. 32 . 4 2.10–2.06 210206 10 (2.10–2.0 periods 210 2.1 209 09 HfNd (Hf-Nd 25 5 2. texture 23 18 8 1. 2.9, 29 9 -2.9 mantlederived mantle derived period 26 6 20 26301 263 2630± 0. -0 -1 -3. 2.9 2.10–2.0 21020 (2.10–2. 21 -2. - -3 2.10–2. 2102 (2.10–2 -2 2.10–2 (2.10– 2.10– (2.10 (2.1 (2. (2 (

Abstract This article discusses the geochemical and petrological evolution of the São José do Campestre granite complex (SJCgr), the last Neoarchean plutonic event so far described in the São José do Campestre massif in NE Brazil. We report field, petrographic, zircon U-Pb dating, and whole rock and mineral chemistry for representative SJCgr samples. Laser ablation zircon U-Pb data indicate that the granite emplacement took place at 2664 ± 13 Ma. The rocks comprising the SJCgr have relatively well-preserved primary textures and fabrics and compositions varying from gabbro to syenogranite. Major and trace element contents reveal a metaluminous, calc-alkaline through transitional to alkaline signature, and LILE- and LREE-enriched series analogous to late Archean sanukitoid and modern arc granitoid. The evolution of the SJCgr is envisaged as follows: (1st) partial melting of a metasomatized mantle (2.5–3.0 GPa, ~85–102 km, 1,000–1,200°C), generating a basaltic to basaltic andesitic magma; (2nd) fractional crystallization (FC) of olivine at mantle or lower crustal depth, leading to the parental magmas of the magmatic series; and (3rd) 40–15% FC of olivine gabbro-norite and olivine monzonite cumulates (400–600 MPa, 15–23 km). The SJCgr shares similarities with post-collisional granitoids and, thus, would represent the last Neoarchean episode of mantle-derived magma in Northeastern Brazil. SJCgr, , (SJCgr) Brazil field petrographic UPb U Pb dating samples 266 1 Ma wellpreserved well preserved syenogranite metaluminous calcalkaline calc signature LILE LREEenriched LREE enriched granitoid follows 1st st (1st 2.5–3.0 2530 2 5 3 0 (2.5–3. GPa 85102 85 102 ~85–10 km 1,000–1,200°C, 10001200C C 1,000–1,200°C 000 200 1,000–1,200°C) 2nd nd (2nd (FC depth 3rd rd (3rd 4015 40 15 40–15 gabbronorite norite 400–600 400600 400 600 (400–60 MPa 1523 23 15–2 km. . km) postcollisional post collisional thus mantlederived derived (SJCgr 26 2.5–3. 253 (2.5–3 8510 8 10 ~85–1 00 20 401 4 40–1 400–60 40060 60 (400–6 152 15– 2.5–3 25 (2.5– 851 ~85– 40– 400–6 4006 6 (400– 2.5– (2.5 ~85 400– (400 2.5 (2. ~8 (40 2. (2 ~ (4 (