Dissertações em Geologia e Geoquímica (Mestrado) - PPGG/IG

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2604

O Mestrado Acadêmico pertence ao Programa de Pós-Graduação em Geologia e Geoquímica (PPGG) do Instituto de Geociências (IG) da Universidade Federal do Pará (UFPA).

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Afinidades petrológicas e geocronologia U-Pb em zircão de ortognaisses do Complexo Gnáissico-Migmatítico Água Azul, Terreno Sapucaia, Província Carajás.
(Universidade Federal do Pará, 2024-10-09) PINTO, Eliziane de Souza; OLIVEIRA, Davis Carvalho de; http://lattes.cnpq.br/0294264745783506; https://orcid.org/0000-0001-7976-0472
The Água Azul do Norte area is part of the geological context of the Carajás Province, precisely in the Sapucaia Terrain, according to the recent tectonic compartmentalization proposals presented by the Granitoid Petrology Research Group (GPPG/UFPA). This region is formed by a mesoarchean orthognathic basement with TTG affinity (Água Azul GneissicMigmatitic Complex; 2.93 Ga) associated with late Mesoarchean intrusions with sanukitoid signatures (Água Azul and Água Limpa Granodiorites; 2.88-2.87 Ga), high-Ba-Sr sodic (Nova Canadá Granodiorite; 2.89-2.87 Ga) and high-K calc-alkaline (Boa Sorte Granite; 2.89- 2.85 Ga) signatures. The review of geological and petrographic data indicated that the TTG crust of Água Azul do Norte is compositionally heterogeneous and records strong evidence of progressive metamorphism and migmatization. Therefore, this work reclassifies this TTG basement as being formed by orthogneisses, which occasionally present variations to tonalitic to quartz dioritic compositions that resemble fragments of a more primitive, intensely deformed and gneissified crust. These varieties show compositional banding in an E-W direction, often disturbed by shear bands and drag folds. Considering the classification of migmatites, they have an orthognathic paleosome and leucosomes rich in Qz+Pl±Bt parallel to the banding (stromatic metatexite) and frequentely outlined by mafic aggregates (melanosome rich in biotite and hornblende). They form four compositional varieties: i) hornblende±biotite tonalitic orthogneiss (HBTnl), ii) clinopyroxene-hornblende tonalitic orthogneiss (CHTnl), iii) epidote-biotite orthogneiss quartz diorite (EBQzD) and iv) hornblende-biotite orthogneiss quartz diorite (HBQzD). They present a large proportion of mafic minerals (M'> 15%), especially biotite and hornblende, which can occur slightly stretched along the foliation plane. Plagioclase and secondary quartz are abundant and occur in the matrix or, in the case of plagioclase, as phenocrysts, while alkali-feldspar and primary quartz are practically insignificant. Whole rock geochemical analysis indicated that samples MED-120A (EBQzD) and MEP-53B (HBQzD) present moderately magnesian character, medium-K calcium-alkaline signature, relative depletion in K2O, MgO, Ba, Ni and Cr and enrichment in Na2O, Al2O3, TiO2, Fe2O3 and Zr, reflecting a certain affinity with traditional tonalite-trondhjemitic associations. The presence of many zircon crystals with igneous features preserved in these samples marks the crystallization age of the protolith at 3.06 Ga, suggesting that they are crustal fragments approximately 100 Ma older than the underlying crust (Água Azul Orthognathic Complex). MED-144 (HBTnl) exhibited a strongly magnesian character, high-K calcium-alkaline signature, high K2O/Na2O ratio and enrichment in MgO, Ba, Ni and Cr, very similar to the composition observed in sanukitoids. The U-Pb data obtained for this sample indicated a crystallization age of 2.92 Ga, similar to that observed in sanukitoids described in the Ourilândia do Norte region (Arraias Granodiorite). The other samples showed significant contents of compatible elements (e.g. Fe, Mg, Ni, Cr) and moderate contents of incompatible elements (e.g. K, Rb, Ba, Sr, Zr, Ti) and revealed an intermediate behavior between TTGs and granitoids enriched in Mg, as well as a strong affinity with the São Carlos Orthogneiss (2.93 Ga) described in the same terrain. Concordant U-Pb ages obtained for samples MED-95A (HBTnl) and EDC-28B (CHTnl) indicated acrystallization at 2.95-2.93 Ga contemporaneous with the emplacement of the Água Azul TTGs and the São Carlos Orthogneiss. The textural behavior of the quartz and mafic minerals indicates dynamic recrystallization mechanisms at intermediate to high temperatures (~500-650ºC), while the morphology observed in the migmatites (stromatic metatexitic and leucosomes with hydrated minerals) suggests that there was a low amount of melt produced and fluids participation in the partial melting process. Combined with the mineral paragenesis (Pl+Qz+Bt±Hbl±Ep), these factors point to a granitic protolith metamorphosed under amphibolite facies conditions, with the migmatization being strongly contemporaneous with the deformation and peak of the regional metamorphism described in the Carajás region (2.89 Ga; MED-95A).
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As águas subterrâneas de Belém e adjacências: influência da Formação Pirabas e parâmetros físico-químicos para medidas de qualidade
(Universidade Federal do Pará, 1996-04-08) SAUMA FILHO, Michel; LIMA, Waterloo Napoleão de; http://lattes.cnpq.br/1229104235556506
In the Metropolitan Region of Belém (PA) the water supply to the population comes from springs (physiographic area of Utinga) and from a network of positional tube wells, in general, in more remote urban areas or where pumping is precarious. This work evaluates the groundwater used in the Metropolitan Region of Belém, correlating data of physical, physical-chemical and chemical parameters, in an attempt to compose an understandable picture about the quality of these waters, and to verify the influence that they suffer from the geological units in which they are located. the aquifers that preserve them are located. To carry out the work, water samples were collected in two different seasonal periods: dry and rainy. After exhaustive consultation of the files of companies, institutions and researchers, 17 tubular wells were selected, 9 in Belém, 5 in Icoaraci, 2 in Mosqueiro and 1 in Ananindeua (Annex A). The most frequent turbidity indices were between 9 and 14 units (ppm of SiO2), but some wells showed higher values (33, 41 and 71 ppm of SiO2. Only in some cases, this turbidity can be immediately correlated with the silica content obtained by chemical analysis. The most frequent color measurements are in the range from zero to 7.5 U.C., with the zero index predominating. However, some wells showed a value above 100 U.C. and others, less frequent, with indices varying between 20 and 60 U.C. The pH and electrical conductivity were quite different parameters. Thus, the highest pH and electrical conductivity indices were verified in the aquifers of the Pirabas Formation. In these cases, the pH was around 6 .4 to 7.6 and conductivity between 231 and 362 µS/cm, with a discontinuity at 87.5 µS/cm, also attributed to a well associated with the aforementioned Formation. More acidic waters (pH below 6.38 and above of 4.01) are certainly attributed to the aquifers of the Barreiras and Post-Barreiras Group. The chemical constituents, notably the contents of Ca2+, Mg2+, Na+ and K+, are consistent with the interpretation of the numerical values of pH and electrical conductivity. Without exception, the concentrations of Ca2+ are higher than those of the other cations, establishing a decreasing order according to Ca2+> Mg2+> Na+>K+, with some inversion between Na+ and Mg2+. The highest concentrations of Ca2+ (soon followed by Mg2+) result from the dissolution of carbonates present in the Pirabas limestone. In fact, confirming this assertion, the concentrations of HCO-3 are also much higher than the concentrations of Cl- and SO2-4. It is to be expected, therefore, that the dissolution of Pirabas sediments produces higher concentrations of Ca2+ and HCO-3. The silica and iron contents also discriminate such waters. In general, higher silica contents correspond to greater depths, as would be expected, taking into account the action of chemical weathering on silicate minerals. As for iron, this constitutes a differentiating parameter of the waters of the Pirabas Formation, almost always at much lower levels than the corresponding values associated with the Barreiras and Post-Barreiras aquifers, with, however, exceptions, in which appreciable indices of iron related to Pirabas sediments. It should be noted that the Pirabas Formation appears in the Metropolitan Region of Belém almost always at depths greater than 100 m, although there are records of smaller depths, but these are apparently rarer situations, as is the case with well number 3. , on the University Campus, near the Guamá River, with a depth of 76 m, and the 94 m well of the Museu Paraense Emílio Goeldi, in the central area of the city (Annex A). The exhaustive consultation of the aforementioned archives of institutions, companies and researchers led to the realization that many tubular wells installed in the urban area use water associated with the Barreiras and Post-Barreiras aquifers, where the pH values are almost always, below 6 units, and electrical conductivity measurements rarely reach 100 µS/cm. Finally, it appears that there is a need for greater investments in order to increase the prospection and use of groundwater in the region, as these, in addition to dispensing with treatment prior to distribution, are still a source of resources, not dimensioned, but of great potential.
Acesso aberto (Open Access)
Assinatura geoquímica do ouro na Província Mineral do Tapajós, Cráton Amazônico: o exemplo dos depósitos São Jorge e São Chico
(Universidade Federal do Pará, 2025-06-19) GOMES, Iolanda Clara do Carmo; LIMA, Rafael Guimarães Corrêa; http://lattes.cnpq.br/6751523860876497; LAMARÃO, Claudio Nery; http://lattes.cnpq.br/6973820663339281; https://orcid.org/0000-0002-0672-3977
Gold has a great economic importance, and the determination of its geochemical and isotopic signatures, exploited in Brazil’s main mineral provinces, has become a valuable tool not only for mineral exploration but also for tracing its origin and circulation. The aim of this study is to characterize and compare the chemical composition of gold from two different deposits using scanning electron microscopy paired with energy-dispersive spectrometry (SEM‑EDS), to evaluate the viability in differentiating provenance on local and regional scales, and to discuss the factors controlling element distribution in native gold. São Jorge and São Chico are gold deposits located in the eastern portion of Tapajos Mineral Province, aligned along the Tocantinzinho lineament (WNW‑ESE). The gold mineralization at São Jorge deposit consists of a paragenesis formed by gold + pyrite + chalcopyrite ± sphalerite and, rarely, galena, which host two generations of gold with distinct chemical compositions. These gold phases occur either in quartz veins and/or in sulfide disseminations in strongly hydrothermally altered host rocks. In this deposit, gold is mainly hosted by pyrite, occurring in the form of inclusions with high Au contents (84.27–91.02 wt%) and filling pyrite fractures with a composition richer in Ag (7.86–15.72 wt%). The geochemical and textural differences indicate at least two distinct mineralizing events. In contrast, the São Chico deposit shows a paragenesis formed by gold + pyrite + galena + sphalerite ± chalcopyrite, in which gold occurs as electrum within polymetallic sulfide‑bearing quartz vein systems. Here, gold is mainly hosted by galena, and textural relationships between these two minerals suggest simultaneous precipitation under low‑temperature conditions. Gold in this deposit also occurs with chalcopyrite and sphalerite, as reflected in its chemical composition, which shows higher average of Cu (0.44 wt%) and Zn (0.42wt%) contents, respectively. Principal component analysis (PCA) identified Ag, Fe, and Te as the elements with the greatest potential for gold discrimination between these two deposits. Gold microparticles from the São Jorge deposit exhibits a geochemical signature with higher contents of Au (73.82–91.02 wt%), Fe (0.54–6.21 wt%), and Te (0.37–3.61 wt%), compared to gold from the São Chico deposit, which displays higher concentrations of Ag (29.82–51.42 wt%).
Acesso aberto (Open Access)
Caracterização mineralógica com espectroscopia de reflectância por infravermelho (SWIR): exemplo do Complexo máficocarbonatítico Santana, sul do Cráton Amazônico
(Universidade Federal do Pará, 2021-09-21) COSTA, Jhoseph Ricardo Costa e; FERNANDES, Carlos Marcello Dias; http://lattes.cnpq.br/0614680098407362; https://orcid.org/0000-0001-5799-2694
On the border of the Pará and Mato Grosso states, in the Amazonian Craton, municipality of Santana do Araguaia (PA), there is a volcano-plutonism named Santana mafic-carbonatitic complex. This set houses the Serra da Capivara phosphate deposit. A lower mafic-ultramafic member reveals plutono-volcanic lithofacies with pyroxenite, ijolite, apatitite, and alkaline basalt. Autoclastic lithofacies contains poorly selected deposits of massive polymictic breccia, lapilli-tuff, crystal tuff, and ash tuff. Volcanogenic epiclastics rocks cover these lithofacies. The upper carbonatite member contains plutonic lithofacies with coarse calcite-carbonatite (sövite). Fine carbonatite veins with pervasive carbonatic and apatitic alterations crosscut this lithotype. Minor thick apatitite occcurs associated to this member and represents the protore of the deposit. Effusive volcanic lithofacies reveals fine calcite-carbonatite (alvikite) with porphyritic, equigranular, or aphanitic textures. A poorly sorted lithofacies of crystals tuff, lapilli-tuff, and massive polymictic breccia completes this member. Stocks and syenitic dykes invade these lithofacies. Detailed mapping suggests that the complex is a volcanic caldera in which large zones of hydrothermal alterations occur with reddish, brownish red, and yellowish carbonatitic rocks. Petrographic observations reveal paragenesis of barite + fluorapatite + calcite + dolomite ± quartz ± rutile ± chalcopyrite ± pyrite ± monazite ± magnetite ± hematite. The application of short wave infrared spectroscopy (SWIR) revealed the chemical characteristics and their importance in the crystallinity of most of these hydrothermal minerals, such as radicals (OH- and CO3), H2O molecule, and cation-OH bonds such as Al-OH, Mg-OH, and Fe-OH. The main mineral phases identified were dolomite, calcite, serpentine, chlorite, muscovite with low, medium, and high aluminum, montmorillonite (Ca and Na), illite, nontronite (Na0.3Fe2((Si,Al)4O10) (OH)2·nH2O), and epidote. The data suggest a control by temperature, fluids composition, and fluid/rock ratio during the evolution of the Santana mafic-carbonatitic complex. This low-cost exploratory technique, which is applied in hand-held samples or drill holes on a large scale, is promising in characterization of volcano-plutonic centers in regions subjected to severe weathering conditions, as well as helping to develop models for prospecting mineral deposits of Rare Earth Elements (e.g. Nd, La) associated with alkaline-carbonatitic complexes. We can even combine this tool with artificial intelligence algorithms for more robust and faster results.
Acesso aberto (Open Access)
Desenvolvimento de uma metodologia para análise química de inclusões silicáticas em cristais de quartzo: estudo de caso em granitos estaníferos da Mina Pitinga (AM)
(Universidade Federal do Pará, 2021-05-02) SANTOS, Gabrielle Cristine Silva dos; BORGES, Régis Munhoz Krás; http://lattes.cnpq.br/4220176741850416; https://orcid.org/0000-0002-0403-0974
Silicate inclusions (melt inclusions) are small globules of silicate melt, containing some combinations of crystals, glass and vapor, entrapped in different minerals during their growth, and can be found in volcanic and plutonic rocks. They are easily identified in volcanic rocks. On the other hand, one of the major difficulties in the study of melt inclusions in plutonic rocks is their identification, because, after being trapped, their evolution results in total or partial crystallization. Based on international literature, they provide important information about the origin, nature of magmas and their petrological evolution. In addition¸ the detection of metals in melt inclusions is a unequivocal geological evidence of the genetic association of these elements with magmatic liquids (source) and is crucial in the study of orthomagmatic or hydrothermal deposits. The techniques for studying silicate inclusions for petrological and metallogenic purposes have evolved very rapidly in the last four decades, but it is a methodology that has not yet been implemented in Brazil, both due to the absence of laboratories with adequate equipment and the inexistence of research groups engaged in this field. Recently, pioneering studies were developed at the CDTN (Centro de Desenvolvimento da Tecnologia Nuclear), in Belo Horizonte (MG), with the tin granites of the Pitinga mine (AM), through high temperature microthermometric experiments and analysis of trace elements by LA-ICP-MS, in silicate inclusions hosted in quartz crystals of these granites. However, the tests were carried out on doubly-polished sections, which made it difficult to perform chemical analyzes of major elements by electron microprobe, since the inclusions were very deep in the quartz crystals, and any attempt at polishing to expose the inclusions would damage the samples. Based on this preliminary experience, this specific work is a technique for preparing quartz crystal concentrates containing silicate inclusions, using as such tin granites from the Pitinga mine (AM), representatives of the later facies of the Madeira pluton, porphyritic hypersolvus alkali feldspar granite and albite-rich granite. Thus, the developed work at the Laboratório de Inclusões Fluidas, with the crucial support of the Oficina de Laminação, the Laboratório de Análises Químicas and the Laboratório de Microanálises of the Instituto de Geociências of the Universidade Federal do Pará (UFPA), allowed the research to establish a routine involving the following steps: detailed petrography; crushing and grinding of the samples; granulometric separation; preparation of quartz crystal concentrates; muffle furnace heating and cooling experiments; selection of crystals with appropriate inclusions; assembly of the crystals in mounts with epoxy resin and subsequent polishing; monitoring and imaging of inclusions through the SEM; particle analyzes by EDS and, finally, analysis of major element (WDS) by electron microprobe. The microanalytical data (major elements) chosen especially in those silicate inclusions containing two or more solid phases (glass, spherical globules), demonstrated that the preparation technique provided a good exposure of the inclusions. In this way, the methodology developed in this work is relevant to the study of silicate inclusions and can be applied for the preparation of concentrates of any transparent magmatic mineral (quartz, olivine, pyroxene, plagioclase, etc.), host of silicate inclusions, and that can be analyzed by any of the traditional microanalytical techniques (electron microprobe, LA-ICP-MS, Raman spectroscopy, SEM, etc.).
Acesso aberto (Open Access)
Estudo geoquímico e isotópico (U-Pb/Lu-Hf) de novas ocorrências de granitos tipo-A no Domínio Carajás.
(Universidade Federal do Pará, 2023-04-18) AFONSO, Jully Mylli Lopes; OLIVEIRA, Davis Carvalho de; http://lattes.cnpq.br/0294264745783506; https://orcid.org/0000-0001-7976-0472
The Carajás Mineral Province was the setting of an extensive magmatic event, marked by anorogenic granitic intrusions and associated dykes. Geological mapping methods carried out in the central portion of the Canaã dos Carajás Domain allowed the individualization of two new anorogenic granitic stocks. These granites occur as isotropic, semicircular shaped stocks, which occur as intrusions in Archean granitic rocks of the Vila União and Cruzadão granite suites. And are classified as monzogranites and divided into biotite-monzogranite equigranular facies (BMzE) and biotite monzogranite porphyritic (BMzP) facies, where biotite is the main ferromagnesian mineral and are often associated with fluorite, in addition to allanite, zircon, apatite and epidote. They are meta- to peraluminous, with a high content of HSFE iron-related with a reduced to moderately oxidized character. When compared to others type-A granites of the Carajás Mineral Province, these granites display significant contrasts with the Jamon and Velho Guilherme suites and are similar to those observed in the Serra dos Carajás suite and, consequently, the Gogó da Onça Granite. Geochronological data of U-Pb in zircon revealed that crystallization age of these granites is ~1893 ± 13 Ma, and associated with isotopic data of Lu-Hf indicate crustal sources for these rocks, with strongly negative ƐHf values ranging from -14 at -17°C and TDM between 3.38 Ga to 3.57 Ga. Based on this informations, the geochemical modeling imply that these granites were generated from partial melting of tonalitic granites of similar composition to the Arco Verde Tonalite or Caracol Tonalite from the Rio Maria Domain. Such results are suitablewith the hypothesis that these granites were generated from a fusion of Archean granitoids and placed in a shallow crust between 1.88 and 1.86 Ga.
Acesso aberto (Open Access)
Estudo sedimentológico da Formação Pimenteira (Devoniano) na borda sudoeste da bacia do Parnaíba (TO)
(Universidade Federal do Pará, 1998-04-15) SILVA, Valter Fernandes; CAPUTO, Mário Vicente; http://lattes.cnpq.br/1028384858323270
The part of the Pimenteira Formation studied occurs in the southwest portion of the Parnaíba Basin, in the region between the cities of Paraíso, Miranorte, Miracema, Tocantinea, Pedro Afonso and Itacajás in the State of Tocantins. This formation is considered to be deposited in a transgressive sea system tract of Middle and Late Devonian age (Givetian to Famenian). In the area on stage, the studies of the facies made it possible to individualize three associations of facies named here as A, B and C that were deposited on a shallow marine platform during transgressive sea level, regressive sea level and high sea level, respectively. These facies associations were interpreted as a product of the following depositional environments: 1) LAMMA MARINE PLATFORM (association of facies A) represented by F1 (laminated shale facies), Alp (sandstone with plane-parallel lamination and Aab (sandstone intercalated to claystones with sand pockets) where the deposition took place mainly from fine suspended sediments (pelites) intercalated with fine to very fine sandstones (psamites) deposited under the influence of oscillatory and tractive flow originated by waves; 2) PROXIMAL GLACIOMARINHO with SUBGLATIAL CHANNEL, associated (association of facies B), represented by facies Dmm (massive diamictite), Acf (sandstone with fluidized clast), F1 (laminated shale), Pgm (massive coarse paraconglomerate), Pfm (massive fine paraconglomerate) and Agm ( massive coarse sandstone), were deposited from glaciers, with associated subglacial channels, ice rafts and/or icebergs that displaced from the continent, floated in the sea, released generating melt water bringing a large amount of fine and coarse sediments, forming a plume loaded with suspended sediments in front of the gallery. With the decrease in energy, extensive layers of mud are deposited, with pebbles and gravels, dispersed, being released from ice rafts and/or icebergs, as they melt. The facies F1, Pgm, Pfm and Agm represent a bar deposit remaining from a subglacial channel. Subglacial channels discharge coarse sediments in front of the glacier that can be transported further by turbidity currents forming lenticular or layered deposits interspersed with diamictites; 3) SHALLOW MARINE PLATFORM UNDER THE ACTION OF STORMWAVES (association of facies C) represented by facies F-A1 (shale-laminated sandstone), F1-S (laminated shale interleaved with siltstones), Aco (sandstone with wavy cross bedding truncated by wave), Ap (sandstone with plane-parallel bedding), Apt (sandstone with plane-parallel and tabular cross bedding), Acot (sandstone with wavy truncated wave and tangential cross bedding), Ach (sandstone with hamocky cross bedding), Aptb (sandstone with plane-parallel and cross-tabular bioturbated bedding), Apmo (sandstone with plane-parallel bedding and wavy marks), Amg (massive sandstone with dispersed granules and pebbles) and Pm (massive paraconglomerate). The deposits are characteristic of platform bars with dominant hummocky structures, attesting to the action of storm waves, covered by extensive layers of marine shales deposited during the good weather phase. This facies association predominates in the upper portion of the Pimenteira Formation gradually passing to the deformed sandstones and diamictites of the Cabeças Formation east of the town of Pedro Afonso.
Acesso aberto (Open Access)
Geoquímica e geocronologia U-Pb shrimp dos granitóides TTG da área de Ourilândia-Tucumã, Província Carajás-SE do cráton amazônico.
(Universidade Federal do Pará, 2023-11-17) REIS, Yury Haresson da Costa; OLIVEIRA, Davis Carvalho de
The rocks that make up the TTG crust in the northern area of Ourilândia do Norte - Tucumã are predominantly tonalitic and show strong petrographic and geochemical affinities with other TTG occurrences in the Carajás Province, which occur in the Rio Maria Domain and Carajás Domain. The granitoids were differentiated based on the occurrence domains of rocks from the Xingu Complex. They exhibit a varied structural pattern, with a tendency towards N-S and concentric patterns. These granitoids are predominantly composed of tonalites with subordinate trondhjemites and granodiorites. The U-Pb zircon crystallization age obtained from the tonalitic variety was 3.00 Ga. The trondhjemites are characterized by higher sodium concentration (Na2O/K2O ratio between 4.24-7.89) and low content of ferromagnesian elements (6 < FeO* + Mg + TiO2 + MnO < 8), while tonalites show sodium depletion (Na2O/K2O ratio between 1.79-3.20) and tend to be enriched in ferromagnesian elements (8 < FeO* + Mg + TiO2 + MnO < 13), with some samples falling within the field of hybrid granitoids, and they are also metaperaluminous (A/NK 1.5-2.0; A/CNK ~1). The Archean is characterized by developing thick sequences of greenstone and TTG plutons, forming dome-like structures and ridges in some cratons, such as those reported in the eastern Pilbara (Australia) and Dharwar (India) cratons. In the model adopted for the Ourilândia-Tucumã area, the generation of the initial stages of TTG magma in the Carajás Province sourced from metabasalts of the Tucumã-Gradaús Group's greenstone belt sequence. This occurred in a scenario involving the partial melting of the base of a thickened mafic oceanic protocrust due to interactions between the lithosphere and convective currents in the asthenospheric mantle, resulting in high-ETRP TTG melt. Dispersed crustal drips formed under increasing pressure and temperature conditions in this context. The partial melting of metabasalt within these drips produced felsic melts that intruded the overlying crust, forming low-ETRP TTG.
Acesso aberto (Open Access)
Metalogênese do depósito aurífero Volta Grande, Domínio Bacajá (PA), Cráton Amazônico: aplicação de espectroscopia de infravermelho VNIR-SWIR.
(Universidade Federal do Pará, 2024-02-27) PARESQUI, Brenda Gomes Silva; FERNANDES, Carlos Marcello Dias; http://lattes.cnpq.br/0614680098407362; https://orcid.org/0000-0001-5799-2694
The world-class Volta Grande gold deposit contains measured reserves of ~6.0 Moz at 1.02 g/t, divided into north and south exploration blocks. It is inserted in the geological context of the Bacajá Domain and was affected by the Trans-Amazonian Cycle (2.26–1.95 Ga). Part of the mineralization is hosted in a group of gneisses and mylonitized granitoids in amphibolite facies of medium to high metamorphic grade of the Três Palmeiras Group (2.36 Ga). Recent research in the northern block has revealed the presence of late volcanics and plutonics, with isotropic texture and intermediate to felsic compositions, which host disseminated gold in different types and styles of hydrothermal alteration, as well as in quartz and carbonate (±sulfides) venules and veins. Thus, this Master's Thesis represents the continuity of research in the northern block of this repository with the application of the VNIR–SWIR (visible-near and short-wave infrared) infrared spectroscopy technique. This tool helps to explain in detail the configuration of the hydrothermal system, contributing to a better understanding of the genesis of the deposit. The mineralogy observed by spectroscopy in metamorphic rocks confirms the occurrence of potassic, propylitic, intermediate argillic, pervasive carbonate, and advanced argillic hydrothermal alterations types. The latter occurs associated with high levels of gold and alunite, a mineral indicative of epithermal systems with high-sulfidation. In turn, the isotropic volcanic and plutonic rocks present more developed, intense, and larger-volume hydrothermal alterations. They reveal greater diversification of hydrothermal minerals, where jarosite is the superior indicator of advanced clay alteration, which is also consistent with high-sulfidation epithermal mineralizations. In addition, the appearance of rhodochrosite, pyroxmangite, and galena, mainly related to volcanic rocks of andesitic and dacitic compositions, suggests an epithermal system of intermediate-sulfidation. The geological features present in the region and the hydrothermal alterations, especially the propylitic alteration in the rocks with allanite, clay minerals, montmorillonite, and zeolites, portray a typical epidote subzone of a low-temperature propylitic alteration that are genetically related to the medium-depth intrusions where they appear hydrated porphyry stocks. In this way, the Volta Grande gold deposit reveals characteristics compatible with rare and base metals porphyry and epithermal mineralizing systems, already identified in other regions of the Amazon Craton. The high-sulfidation conditions at the northwest portion of this repository and intermediate-sulfidation at the southeast region point to a transitional environment. The VNIR–SWIR spectroscopy method represents an important tool that identifies and characterizes hydrothermal minerals quickly and efficiently, as well as differentiating them from weathered ones. In general, it becomes a significant prospective guide when robustly analyzing minerals that are difficult to recognize by other methods such as conventional optical microscope or scanning electron microscope (SEM). The results presented here represent a remarkable contribution to the geological and metallogenetic knowledge of the Bacajá Domain, as well as the Amazonian Craton as a whole, pointing out the potential for identifying economically viable deposits of precious and base metals associated with volcanic and plutonic systems that occur in a vast area of this domain.
Acesso aberto (Open Access)
Morfologia e composição de rutilo como guia prospectivo para depósitos de Au: o exemplo do depósito São Jorge, Província Mineral do Tapajós
(Universidade Federal do Pará, 2025-03-18) MEDEIROS, Marcos Flávio Costa; LAMARÃO, Claudio Nery; http://lattes.cnpq.br/6973820663339281; https://orcid.org/0000-0002-0672-3977
The Tapajós Mineral Province (PMT), inserted in the context of the Tapajós-Parima or Ventuari-Tapajós geochronological province, is recognized as the largest gold-bearing province in Brazil. The São Jorge Jovem Granite (GSJJ), located east of the PMT in a heavily fractured and hydrothermalized area, hosts gold mineralization. The GSJJ exhibits calcium-alkaline affiliation K-rich, composed of rocks of monzogranitic and leucomonzogranitic composition, with amphibole and biotite as the main mafic minerals. Pb-Pb dating of zircon in leucomonzogranites revealed a crystallization age of 1891±3 Ma. TiO2 polymorphs are common accessory phases in several types of rocks. In nature, it occurs in three main polymorphs: anatase and brookite, which are representatives of low temperatures and pressures, and rutile, at medium to high and ultra-high pressures and temperatures. Of these, rutile is the most common polymorph in the Earth's crust. The samples and polished blades used in this research come from drilling holes carried out by Rio Tinto Desenvolvimento Minerais (RTZ) in GSJJ. TiO2 polymorphs are represented by thin (10-100μm) anhedral crystals in or surrounding biotite. Samples from the mineralized zone show varied hydrothermal alteration, with rocks in the propylitic and phyllic alteration stages. TiO2 polymorphs form acicular aggregates or aggregates with a skeletal texture, predominantly replacing titanite. Spot electron microprobe analyses conducted on individual crystals and aggregates of rutile crystals revealed significant compositional variations, particularly concerning the contents of Nb, Al, Zr, V, and W. Rutile crystals from the non-mineralized zone (NMZ) exhibited higher levels of Nb (> 5,000 ppm) compared to crystals from the mineralized zone (MZ; predominantly < 3,000 ppm). Rutile crystals from the MZ display a trend of Al enrichment and V. Crystals from the NMZ sometimes show enrichment in Fe but are always accompanied by levels considered to be Nb. ZM crystals exhibit a trend of enrichment in W, V, and Sb and are always depleted in Nb. Analysis of rutiles demonstrates that their chemical composition can be used to distinguish between mineralized rocks and other types of non-mineralized rocks. The results indicate that the trace element composition of rutile, mainly the V content, and other elements such as Al, Zr, Sb, W, offer the best indications of mineralization in gold deposits.
Acesso aberto (Open Access)
Petrografia e geoquímica do Granito Manda Saia, Província Carajás.
(Universidade Federal do Pará, 2020-09-09) SANTOS, Marcelo Reis; OLIVEIRA, Davis Carvalho de; http://lattes.cnpq.br/0294264745783506; 0294264745783506
The Manda Saia granite is located to southeast of the of Xinguara town and it is represented by two semicircular plutons separated by the Mesoarquean basement of the Rio Maria Domain. The bodies crosscut in the northern portion the Mesoarquean TTG granitoids and the Rio Maria Granodiorite, and in the south, eastern and western portions they are intrusive in the metabasalts of the sequence greenstone belt of the Babaçu Group. The Manda Saia pluton is formed by rocks of isotropic aspect, grayish pink in color and monotonous textural variation. They are hololeucocratic rocks of medium-to-coarse heterogranular texture, occasionally porphyritic, which are classified as monzo- and syenogranites. Biotite is the main ferromagnesian mineral and amphibole is rare and interstitial. Secondary minerals are clay minerals, sericite, muscovite, fluorite and chlorite. Manda Saia pluton is formed by peraluminous rocks that present a restricted and high SiO2 contents (74.80 and 77.70wt.%), and high Fe/(Fe+Mg) ratios. Their REE pattern is marked by enrichment in light and heavy REE and moderate negative Eu anomaly. The pluton can be classified as ferrous type-A granite and akin to the reduced types and those most evolved from the oxidized granites of the Carajás Province. The occurrence of interstitial amphibole identified in the Manda Saia granite also is observed in the plutons of the Velho Guilherme Suite. On the other hand, the frequent occurrence of magnetite combined with the compositional aspects of its rocks, also shows that the Manda Saia granite is akin to the leucogranitic facies of the oxidized granites from Jamon Suite. The emplacement of the Granite Manda Saia is linked to extensional tectonics and the transport of magma that resulted in the emplacement of the plutons in shallow crustal levels (~ 1.0 ± 0.5 kbar) through a dyke feeding system.
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Petrografia e mineralogia das alterações hidrotermais associadas ao bloco Sul do depósito aurífero Volta Grande do Xingu, Domínio Bacajá (PA), Cráton Amazônico
(Universidade Federal do Pará, 2025-04-22) PINTO, BRENDA THAYS BARROS; FERNADES, Carlos Marcello Dias; http://lattes.cnpq.br/0614680098407362; https://orcid.org/0000-0001-5799-2694
The world-class Volta Grande gold deposit, at the Bacajá Domain, contains measured reserves of approximately 6.0 Moz at 1.02 g/t, divided into the north and south exploratory blocks. Historically, this mineralization has been classified as orogenic (lode-type) and is found within a set of mylonitized granitoids in the amphibolite facies of medium to high metamorphic degree attributed to the Três Palmeiras Group (2.41 Ga) and the Oca Granodiorite (2.16 Ga). However, recent research on the rocks of the northern block has established a late volcanic sequence with significant gold mineralization. Aiming to contribute to its metallogenetic modeling, this Master’s Dissertation focused on the southern block, involving macroscopic and microscopic petrographic descriptions and the application of VNIR–SWIR reflectance spectroscopy in core samples from the Pequi, Grande, and Itatá targets. First, the results include the petrography of metamorphic rocks, represented by amphibolite and mylonitic granodiorite, and an associated isotropic volcanic and plutonic suite. The data compilation revealed mineral paragenesis related to metamorphic and magmatic-hydrothermal processes. The metamorphic paragenesis reveals regional and dynamic-thermal metamorphisms and moderate overprinting of hydrothermal alterations typical of epithermal systems, associated with the emplacement of the isotropic rocks package. Second, in the isotropic rocks, there is an overprint of hydrothermal alterations and gold mineralization conceivably of intermediate- and high-sulfidation epithermal-type genetically linked to magmatic-hydrothermal systems, with carbonate alteration in a boiling zone and advanced argillic alteration. In conclusion, data integration from the southern block shows, similarly to the northern block, at least two genetically distinct gold mineralizing events that enhanced the grade and tonnage of the Volta Grande deposit, thus representing a new prospective model for the Bacajá Domain.
Acesso aberto (Open Access)
Petrografia, alterações hidrotermais e eventos mineralizantes do Bloco Norte do depósito aurífero Volta Grande, Domínio Bacajá (PA), Cráton Amazônico
(Universidade Federal do Pará, 2021-09-22) SOUZA, Hugo Paiva Tavares de; VASQUEZ, Marcelo Lacerda; http://lattes.cnpq.br/4703483544858128; https://orcid.org/0000-0003-2729-9404; FERNANDES, Carlos Marcello Dias; http://lattes.cnpq.br/0614680098407362; https://orcid.org/0000-0001-5799-2694
The southeastern region of the Amazonian Craton has been the target of several mineral survey programs over the past few years, which have recently led to the identification of the world-class Volta Grande gold deposit, with reserves of ~3.8 Moz at 1.02 g/t, which provides an expectation of 17 years of operation. The deposit is in the municipality of Senador José Porfírio in Pará and is housed in Rhyacian granitoids (2.15 Ga) that occur associated with the volcano-sedimentary Siderian sequence (2.45 Ga) of the Três Palmeiras Group. These units are in the Bacajá Domain, which is formed by belts of high-grade para- and orthoderived rocks and greenstone belt of Archean to Siderian protoliths, reworked during the orogenesis of the Transamazonian Cycle (2.26–2.06 Ga). Granitoids and charnockites sectioned this set in Rhyacian. Part of the mineralization at the Volta Grande is housed in granitoids metamorphosed under medium to high-grade conditions. Local kinematic indicators suggest dip-slip movement in which the greenstone moves up relative to the intrusive rocks. Petrographic descriptions carried out in this work revealed: 1) gray to greenish mylonitic granodiorite, with intense deformation of the main minerals that make up them, such as quartz, biotite, and feldspars. The texture in this lithotype is mainly porphyroclastic. Main metamorphic foliation (S1) is defined by biotite and amphibole, as well as reveals concordant quartz veins and venules. The highest gold contents are distributed in upper amphibolite facies zones. In these, the ore occurs mainly as isolated grains in cm-sized quartz veins and venules associated with pervasive carbonatic alteration that was synchronous to dynamic metamorphism, as well as in a fracture-controlled style. Part of the gold is also associated with a low sulfides content disseminated in the veins and host rock; 2) The metamafic rocks comprise foliated fine- to medium-grained amphibolite and andesite with a dark grayish-green color and nematoblastic texture. Chlorite, calcite, sericite, and opaque minerals are the main secondary phases. These relationships are compatible with lode-type gold systems, usually developed in the transition between greenschist to amphibolite metamorphic facies. Lava flows and dykes of isotropic rhyodacite, rhyolite, and plutonic rocks such as quartz monzonite, granodiorite, monzodiorite, and minor microgranite cut the mineralizing event previously described. Plutonic rocks are medium- to coarse-grained, have a gray color with reddish and greenish portions throughout the profiles, inequigranular texture with quartz, feldspar, biotite, and amphibole. Apatite, zircon, calcite, epidote, and opaque minerals are primary accessories. In turn, volcanics have light gray, black or dark red colors, porphyritic to aphyric texture, and microlithic or felsophyric groundmass. They reveal phenocrysts of plagioclase, amphibole, potassic feldspar, and quartz. This volcano-plutonic system contains potassic, propylitic, intermediate argillic, and/or carbonate hydrothermal alterations in selective, pervasive, or fracture-controlled styles. In hydrothermalized zones, gold occurs as isolated grains disseminated or associated with sulfides, as well as in cm-sized quartz veins in a stockwork arrangement. These characteristics are like those of shallow intermediate- to lowsulfidation epithermal systems already identified in the Amazonian Craton. The Volta Grande data suggest a second overprinted mineralizing event, common in high-tonnage productive gold deposits in China, Finland, and other areas of the planet and represents a new exploration guide for the Bacajá Domain. Several mineralizing events are critical to the economic feasibility and longevity of world-class gold deposits. Thus, new geochemical, geochronological, microthermometric, and stable isotope data will be obtained to better define the genetic modeling of the Volta Grande gold deposit.
Acesso aberto (Open Access)
Petrografia, geoquímica e geocronologia de rochas vulcano- plutônicas orosirianas do SE do Cráton Amazônico: um estudo da fronteira dos domínios Tapajós e Iriri-Xingu
(Universidade Federal do Pará, 2020-06-16) SILVA, Amanda Suany Marinho da; MACAMBIRA, Moacir José Buenano; http://lattes.cnpq.br/8489178778254136
The central part of the Amazonian Craton encompasses the Tapajós (TJD) and Iriri-Xingu (IXD) tectonic domains, which record volcano-plutonic events from the Orosirian times. The boundary between both domains was proposed from Nd isotopes and is marked by the predominance of juvenile paleoproterozoic sources or with little participation of the archaean crust for the TJD, whereas the rocks of the IXD present archaean crustal sources. However, the boundary between these domains is still subject of discussion due to the lack of isotopic data, the homogeneity of the lithotypes and the absence of tectonic structures that could outline this frontier. The study area is in the municipality of Trairão, southwestern Pará state, the probable boundary region between TJD and IXD, where there are occurrences of paleoproterozoic volcano-plutonic associations. We performed in situ U-Pb on zircon by plasmainduced mass spectrometry with laser ablation (LA-ICP-MS), Sm-Nd whole-rock by thermal ionization mass spectrometry (TIMS), together with geochemical analyses and petrographic data aiming to reconstruct the tectonic and chronological emplacement of the magmatic rocks, as well as to better establish the boundary between TJD and IXD. In the study area, the volcanic sequences are represented by the Moraes Almeida, Salustiano and Aruri formations, and the plutonic units correspond to the Creporizão, Parauari (granodioritic and granitic units) and Maloquinha suites. The effusive and volcanoclastic rocks are rhyolites, dacites, andesites, rhyolitic ignimbrites, and tufts. The plutonic units are granodiorites, quartz monzonites, monzogranites, and syenogranites. The geochemical results showed that the rocks of the Creporizão and Parauari intrusive suites (granodioritic and granitic units) have high-K calcalkaline to shoshonitic signature, a meta to peraluminous character, with enrichment in LILE (K, Rb, Ba, and Sr), moderate fractionation of heavy ETR and weak negative Eu* anomalies. Distinctively, the granitoids of the Maloquinha Intrusive Suite and the Salustiano and Moraes Almeida formations have a high-K calc-alkaline signature, from peraluminous to peralkaline character. These rocks present enrichment in HFSE (Zr, Hf, and Th), high ETR contents and pronounced negative Eu* anomalies. In tectonic environment classification diagrams, the granitoids of the Creporizão and Parauari (granitic and granodioritic units) intrusive suites and, Salustiano and Aruri formations showed geochemical affinities with volcanic arc granites (VAG), related to magmatic arc, while the rocks of the Maloquinha Intrusive Suite and the Moraes Almeida Formation are related to intraplate anarogenic environment. The U-Pb zircon dating allowed to identify the oldest plutonic and volcanic rocks, belonging, respectively, to the Intrusive Creporizão Suite, with crystallization age of 1980±6 Ma, and to the unit mapped xi as Salustiano Formation, aged of 1975±11 Ma. The rocks of the Maloquinha Intrusive Suite were generated at 1880±9 Ma, with a volcanic correspondent of the Moraes Almeida Formation of 1877±14 Ma, followed by the plutonic rocks of the Parauari Intrusive Suite (granodioritic unit, aged of 1876±9 Ma, and the granitic unit, of 1867±15 Ma), and the volcanic rocks of the Aruri Formation, generated at 1867±7 Ma. The geochemical characteristics combined with the geochronological data allowed to define a geodynamic evolution involving an context related to magmatic arc environment at ca. 1.98 Ga, which favored the formation of the rocks of the Intrusive Suite Creporizão and Salustiano Formation, followed by an intraplate extensional environment (ca. 1.88 Ga), marked by the coexistence of the types A and I rocks of the Maloquinha and Parauari (granodioritic and granitic units) suites, and Moraes Almeida and Aruri formations. Model ages Nd-TDM (2.31-2.64 Ga), with slightly to strongly negative values of εNd(t) (-1.39 to -7.11), indicate magmas derived from the melting of crustal sources of the Paleoproterozoic and Archaean. These results allowed to draw an NW-SE line, where mainly rocks of paleoproterozoic (<2.5 Ga) and archaean (> 2.5 Ga) model outcrop, belonging, respectively, to the TJD and IXD.
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Petrografia, suscetibilidade magnética e química mineral dos metagabros de Águas Claras, Serra dos Carajás-Pará
(Universidade Federal do Pará, 1997-04-15) SOARES, José Erima Bezerra; DALL'AGNOL, Roberto; http://lattes.cnpq.br/2158196443144675
Acesso aberto (Open Access)
Variabilidade espacial e temporal do manguezal em um estuário subtropical, baía da Babitonga, sul do Brasil
(Universidade Federal do Pará, 2022-12-31) TORRES, Angela Esmeralda Cely; FRANÇA, Marlon Carlos; http://lattes.cnpq.br/8225311897488790; https://orcid.org/0000-0002-3784-7702
Mangroves are indicator ecosystems that respond to global changes in tropical and subtropical regions around the world. Climate changes and variations in sea level significantly influenced mangroves during the Holocene along the Brazilian coast. Here we study mangroves established near the southernmost limit of South America (28°S). Our study is based on a core obtained in the region of the Palmital channel – Baía da Babitonga, State of Santa Catarina (SC), Brazil. Sedimentary, pollen, geomorphological and vegetation analyzes allowed the paleoenvironmental reconstitution during the Late Holocene. The three facies associations found indicated a progradational succession where a tidal plain was developed on the estuary margin. During the first phase, from at least 1440 to ±1286 cal years BP, there was a sandy infratidal plain in the study area. Initially, there were no records of mangroves, but Laguncularia pollen grains were identified from ±1390 cal years BP, indicating that in the region surrounding the collection point, conditions became favorable for the development of the mangroves. After ±1286 cal years BP, the tidal flat developed reaching the present coastline, favored by the stabilization of the relative sea level. Avicennia trees were established on the tidal flat from ±1273 cal years BP. Finally, Rhizophora trees have been established during the last few decades. Probably, the mangrove succession found was favored by climatic conditions related to the increase in temperature during the late Holocene that has caused a migration from the southern limit of the mangrove to the south of the subtropical zone. Modern space-time analysis revealed a recent decrease in mangrove area of ±107 ha between 1986 (4115 Ha) and 2021 (4008 ha). The greatest loss is located in the coastal zone close to the city of Joinville (SC), mainly related to urban expansion. A slight expansion of the mangrove upstream of the channels was observed, which may be related to changes in the relative level of the modern sea and the gradual increase in minimum temperatures in southern Brazil.
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Vetorização geoquímica, caracterização e modelamento 3D de alterações hidrotermais em sistemas cupro-auríferos: exemplo do Complexo Sossego (PA), Província Mineral de Carajás
(Universidade Federal do Pará, 2023-04-18) SANTOS, Antônio Fabrício Franco dos; FERNANDES, Carlos Marcello Dias; http://lattes.cnpq.br/0614680098407362; https://orcid.org/0000-0001-5799-2694
The copper-gold Sossego Complex, Pista, Sequeirinho/Baiano, and Curral/Sossego sectors, is in the southern portion of the Carajás Mineral Province, along with a WNW-ESSE regional shear zone. The main host lithologies that take place at the Complex are granitoids, felsic metavolcanic rocks, and mafic to ultramafic intrusive rocks. This work involved the application of multivariate statistical techniques to define geochemical units and vectors to help with geological interpretation, exploratory guides, and geometallurgy of the Complex concerning the mineralization. Overall, the use of those techniques revealed a good correlation between elemental data and the geochemical units proposed, which allowed coherently defining of the units, major elements, and probable hydrothermal mineralogical paragenesis for the deposits. Individual analyses and elemental correlation of chosen elements in probability diagrams, histograms, binary, ternary, and boxplots were carried out and aimed at identifying the geochemical features and their relation to the mineralogical association. At the Pista sector, at least five geochemical units occur (sodic, sodic-silica, potassic-chloritic, magnesian, and potassic feldspathic), where are highlighted the units with a higher concentration of sodium and silica for zones closer to the orebody. Geochemical vectors that predominate over this sector and that can be considered as trackers or contaminants about the ore zones are As, Al, Ag, Hf, Sr, Te, Zr, Mo, Na, Pb, S, La, W, and U, directly associated with sodic-silica and sodic geochemical units. Ternary diagrams have shown an indicator of paragenesis, which comprises a vector from an initial phase of sodic evolving to potassic. At Sequeirinho/Baiano sector, occur nine geochemical units (sodic, sodic-silica, sodic-ferric, sodic-calcic, calcic-ferric, ferric, magnesian, potassic-chloritic, and potassic feldspathic) in which the paragenesis is observed from the distal to the proximal zones concerning the orebody. Over distal zones, higher sodium concentration is observed, evolving to medium concentration of sodium and calcium, achieving high iron, calcium, and magnesium content nearby the mineralization, showing that the geochemical units related to the copper mineralization of high-grade are calcic-ferric and ferric. Elements such as Ag, As, Bi, Cd, Co, Fe, Ga, Ge, In, Ni, P, Pb, S, Se, Te, and V (secondary Ca, Mg, Mn, Re, Sb, Sn, Th, and U) were the main vectors directly associated with mineralization and calcic-ferric to ferric units. Ternary diagrams of this sector suggest two probable paragenesis vectors, both from initial stages of the sodic unit, although, one of them showed an evolution towards sodic-ferric and the other to a sodic-calcic stage and evolving to calcic-ferric unit afterward. In the Sossego/Curral sector occur seven geochemical units (sodic, sodic-silica, sodic-potassic, potassic, chloritic, ferric, and calcic). This sector has revealed a complex correlation between hydrothermal zoning and geochemical units because of its geological features (breccias, veins, veinlets, and late dissemination). The graphics show that geochemical units that display an affinity with mineralized zones are chloritic, calcic, and ferric (breccia and vein zones). Over the chloritic unit, the highlighted elemental vectors are Ag, Be, Bi, Ca, Ce, Cu, La, Mn, Mo, Ni, P, and S (secondary K, Al, Mg, and Fe). Ferric geochemical unit happens mainly associated with chloritic and calcic zones, although it is not similar due to high iron concentration (>15% Fe), and the main geochemical vectors are As, Cd, Ce, Co, Fe, Ga, Ge, In, La, Re, S, Sb, Se, Sn, Te, U, and Y (secondary Ag, Be, Ca, Cs, Li, Mg, Mn, Mo, and V). The calcic unit corresponds to calcite, actinolite, and epidote-rich intervals in breccias and veinlets that cut chloritic rocks. Its main geochemical vectors are Al, Ca, Cr, Mn, Sc, Sr, V, and Zn (secondary Ag, As, Cd, Co, Fe, Ga, In, S, Se, and Sr). The probable paragenesis vector points to an initial sodic stage, evolving to a potassic stage followed by chloritic. Spatial materialization of the units and geochemical vector was made by 3D modeling obtained by statistical results that were developed, displaying a better visual geological understanding of hydrothermal flow, probable chemical/mineralogical paragenesis, and correlation with mineralization. This work will contribute in the future to the understanding of lithology, structural, and geochemistry of the Sossego Complex, besides provisioning geometallurgical data. This work can benefit open pit operations with direct or indirect reduction of cost, safety increment, and better operational performance of the ore processing.

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