Tectonometamorphic evolution of the Anicuns-Itaberaí Sequence, Southern Brasília Orogen: Evidence of deep burial and syn-collisional exhumation Otávio Passo-Vieira, Rodrigo Prudente Melo, Regiane Andrade Fumes, Gabriel Silveira Brod, Filipe Altoé Temporim, Sergio Willians de Oliveira Rodrigues, George Luiz Luvizotto Journal of South American Earth Sciences, 2026 Metamorphic pressure–temperature (P–T) conditions in the Southern Brasília Orogen are relatively well constrained, particularly in its southernmost segments. However, the central and northern portions need further attention, especially regarding the metamorphism affecting the volcano-sedimentary sequences of the Arenópolis Magmatic Arc (AMA). The Anicuns–Itaberaí Sequence (AIS), located in the southern segment of the AMA, comprises a well-exposed metavolcano-sedimentary succession of mafic to ultramafic metavolcanic rocks, metachert, metarhythmite, marble lenses and quartzite. Well-preserved outcrops in the lowlands surrounding the Serra da Jiboia region, located in the central portion of the study area, were used to investigate the structural features and deformation recorded in metasedimentary rocks of the AIS and two samples of metagreywackes were selected for metamorphic modelling. The analyzed rocks correspond to garnet–chlorite–biotite–muscovite schists and were selected for microstructural analysis, quantitative mineral mapping, and thermodynamic modelling based on electron microprobe analyses. The results indicate that the peak metamorphic assemblage (garnet + biotite + plagioclase + muscovite + rutile +ilmenite) was stable at temperatures above 600 °C and pressures exceeding 0.95 GPa. The metamorphic evolution, inferred from compositional zoning in garnet, defines a clockwise P–T path, with initial garnet growth at 525–555 °C and 0.67–0.77 GPa, a metamorphic peak at 660 °C and 1.16-1.30 GPa, followed by decompression between 550 to 585 °C and 0.65-0.79 GPa. These results indicate that the AIS schists reached high-pressure amphibolite-facies conditions, exceeding those typical of the Barrovian metamorphism, and point to a collisional tectonic regime characterized by deep crustal burial and subsequent exhumation. Deformation structures were chronologically classified into four distinct phases (D 1 to D 4 ). The main deformation event (D 2 ) is characterized by asymmetric folding, while subsequent reverse faulting and shearing (D 3 ) are associated with post-burial exhumation during syn-collisional processes. Microstructural evidence suggests that the metamorphic peak likely occurred between the end of D 1 and the onset of D 2 , indicating that peak mineral growth was broadly synchronous with early stages of the main deformation phase and burial.
Decoding the Structural Architecture of the Northern Copper Belt (Carajás Province) and Bacajá Domain Using Airborne Geophysics (Brazil) Luiz Fernandes Dutra, Gustavo Henrique Coelho de Melo, Brener Otávio Luiz Ribeiro, Filipe Altoé Temporim Minerals, 2026 Copper is a critical metal for the global energy transition. Yet, declining discovery rates and increasing demand necessitate more efficient mineral exploration strategies grounded in a mineral systems approach. The Carajás Province (Amazonian Craton, Brazil) is one of the world’s premier copper-producing regions, hosting several iron oxide–copper–gold (IOCG) and related deposits. The Northern Copper Belt (NCB), located near the boundary between the Carajás and Bacajá domains, records a multiphase deformational and metallogenetic evolution from the Neoarchaean to Paleoproterozoic. Despite extensive previous studies, uncertainties remain regarding the geometry, depth, and continuity of the regional structures that control copper mineralization, as well as the nature of the tectonic boundary between the Carajás and Bacajá domains. As a result, through an integration of airborne magnetic, gravity, gamma-ray spectrometry, morpholineament, and spatial analyses, we characterized the tectono-structural framework of the NCB and the southern Bacajá Domain. This will provide new constraints on the geodynamic evolution of this world-class copper metallogenic belt, elucidating crustal-scale structures and patterns of hydrothermal alteration and fluid pathways, and enhancing understanding of the potential for further discoveries.
Unraveling remagnetization sources using statistical learning L.C. Gallo, M. Domeier, P.Y. Antonio, F. Sapienza, A. Rapalini, E. Font, T. Adatte, R.I.F. Trindade, F. Temporim, J. Tonti-Filippini, P. Silkoset, L. Warren Earth and Planetary Science Letters, 2025 The paleomagnetic archive provides invaluable insights into Earth's history, but its records are often obscured by various geological processes. A prime example is remagnetization, which can replace the original natural remanent magnetization. Although magnetic overprints can be detected by traditional paleomagnetic tests, the mechanisms responsible for them often remain elusive because linking bulk magnetic properties to their microscopic sources is inherently challenging. Here, we bridge this gap by pairing an extensive rock magnetic and geochemical dataset with statistical learning techniques for the first time. Using a Random Forest regressor trained on geochemical data, we accurately predict the growth of fine-grained magnetite in an undeformed late Ediacaran section of remagnetized carbonate rocks from Paraguay. Our modeling results identify the K/Al ratio—alongside K and Sr contents—as key predictors of this remagnetization mechanism. Notably, clay mineralogy analyses further link the K/Al ratio to enhanced clay authigenesis (illitization) driven by K-feldspar dissolution and albitization—processes that also release iron. Together, these findings indicate that remagnetization occurred via authigenic magnetite formation under isochemical diagenesis—without the involvement of external fluids. This novel application of statistical learning to uncover the geochemical drivers of chemical remagnetizations provides a robust framework to investigate and understand these events. It could also open new avenues for their direct dating, thereby significantly enriching the global paleomagnetic record.
The chemistry of beryl as a tool to understand non-emerald bearing pegmatites Flávia Compassi da Costa, Filipe Altoé Temporim, Ráyna Dadalto Durão, Rodson de Abreu Marques, Rafael Matoso Alvarenga, et al. Revista De Geociencias do Nordeste, 2024 O estudo do berilo de pegmatitos não portadores de esmeralda desvenda segredos sobre a formação e desenvolvimento dos pegmatitos, abrindo caminhos para compreender essas formações geológicas. Como um silicato de boro, o berilo se apresenta em diversas cores e formas, refletindo as condições geoquímicas e as impurezas de seu ambiente. Portanto, a análise da composição química do berilo revela detalhes sobre a sua cristalização. Tais variações químicas sinalizam os processos de diferenciação magmática que influenciam a diversidade mineral dos pegmatitos. Este estudo aprofundado não apenas esclarece os mecanismos geológicos por trás da gênese dos pegmatitos sem esmeralda, mas também expande o entendimento sobre a distribuição de minerais e elementos valiosos na crosta terrestre. O estudo do berilo oferece ainda perspectivas sobre a evolução geológica de áreas abundantes em pegmatitos. Este artigo traz uma revisão detalhada das características e comportamento químico do berilo, além de descrever uma rotina para a determinar da fórmula química de berilos por estequiometria, usando análises de microssonda eletrônica.
HYDROTHERMAL ALTERATION ZONES MAPPING USING SENTINEL 2 MSI AND TERRA ASTER DATA IN THE URUGUAY MINE, MINAS DO CAMAQUÃ DISTRICT Rodrigo Carneiro Novaes, Luis Eduardo de Souza, Filipe Altoé Temporim, Luciana Arnt Abichequer Revista De Gestao Social E Ambiental, 2024 Objective: This work has as main objective to evaluate the usage of data from the Terra ASTER multispectral sensor, as well as data from Sentinel 2 MSI for the identification of hydrothermal alteration zones in the Uruguay Mine. Another objective of this work was to map a not-so-great scale deposit that present a hydrothermal pattern associated in a tropical country. Method: Were applied principal component analysis and entropy analysis technique to the ASTER surface reflectance data and principal components only to the surface reflectance MSI data. The field spectra provided were obtained with the ASD FieldSpec-3 High-Resolution spectroradiometer. The samples collected contained spectral features characteristic of minerals such as ferric chlorite, hematite, goethite and illite (Phengite). Result and Conclusion: The ASTER data resulted in a good radial highlighted pattern at the mine location indicating that the processing was able to map the target spectral patterns. The MSI data were processed to map the ferric minerals and presented a pattern highlighting the mine contours and slopes, demonstrating the possible occurrence of minerals containing the aimed spectral features. The entropy usage as an intensity factor applied to intensity-hue-saturation (IHS) fusion on ASTER data improved the reliability of the results, by highlighting the pixels with deepest absorbance features, reducing the uncertainty associated with the process. The results were considered good since both processes showed correspondence in the location of the mine. Implication of the research: This work contributes for the understanding of spectroscopy analysis of alteration minerals related to copper mineralization, and techniques of remote sensing to map them. Originality/value: Good results of the application of principal component analysis in the studied area and application of entropy concept in spectral analysis.
Geochemical soil dynamics on a bimodal post-collisional intrusive complex Kargean Vianna Barbosa, Diego Lang Burak, Carlos Eduardo Veiga de Carvalho, Filipe Altoé Temporim, Danilo de Lima Camêlo, Alexandre Rosa dos Santos Environmental Monitoring and Assessment, 2023 The importance of environmental quality for global social and ecological development, including soil degradation, cannot be overstated. Trace elements dispersed in the environment due to anthropogenic or geogenic activities can result in ecotoxicological impacts, negatively influencing environmental quality. The reference values for soil quality concerning trace elements are primarily based on geological, geomorphological, and pedological patterns. However, intrinsic geological factors may diverge some concentration levels from established norms. Therefore, conducting comprehensive surveys of environmental quality reference values becomes imperative, incorporating geological, geomorphological, and pedological patterns. A deeper understanding of the distribution of these elements is also required. Multivariate analysis proves crucial in compartmentalizing the most relevant factors, particularly in regions marked by bimodal magmatism arising from post-collisional distensional processes, such as the Santa Angélica intrusive suite in southeast Brazil. This study collected soil samples from pastures and natural grasslands with minimal anthropogenic intervention at two depths. These samples underwent various chemical and physical analyses. Statistical techniques such as correlation analysis, principal component analysis, hierarchical clustering, and geostatistics were utilized to interpret the data. The analysis revealed a correlation between the clay fraction and trace elements, demonstrating that clustering is an effective methodology for ascertaining landscape distribution patterns of these components. When compared to quality reference values, it was observed that most soil content levels exceeded both global and local standards. This study suggests that the presence of barium (Ba) in the soil might be due to the isomorphic replacement of feldspathic minerals in acidic and intermediate rocks, whereas molybdenum (Mo) seems to be associated with soils in the domain of porphyritic allanite granite. However, additional research is warranted to determine the concentration factor of Mo in this scenario accurately.
Vertical deformation partitioning across a collapsing large and hot orogen F. A. Temporim, Ricardo Ivan Ferreirae da Trindade, Marcos Egydio‐Silva, Tiago Valim Angelo, Eric Tohver, Caroline Cibele Soares, Lucas Pequeno Gouvêa, Julio Cesar Mendes, Silvia Regina Medeiros, Antônio Carlos Pedrosa‐Soares, Gabriel Gomes Silva Terra Nova, 2023 Featuring 3 000‐km‐long large and hot orogen, the Mantiqueira Province provides a rare opportunity to study the process of gravitational collapse at mid to deep crustal levels. Distinct but contemporary (~500 Ma) post‐collisional intrusions show structures and anisotropy of magnetic susceptibility (AMS) fabrics related to their emplacements, recording different flow patterns. In southern deep‐seated intrusions, ellipsoidal‐shaped roots with gabbroic‐to‐hybrid cores surrounded by granitic rocks show concentric patterns of AMS fabrics that cut across the NE‐trending regional foliation. In contrast, northern intrusions, exposed as the upper sections of batholith‐size bodies of coarse‐grained granite emplaced at the shallow to mid‐crust, show general NS‐trending magnetic fabrics roughly parallel to strike of the orogen and the regional foliation of host rocks. These contrasting magnetic patterns from shallow to deeper crust suggest vertical magma migration from the overthickened orogenic core to be emplaced across its thinner stretched flanks during the gravitational collapse of the orogenic edifice.
A Juvenile Component in the Pre- and Post-Collisional Magmatism in the Transition Zone between the Araçuaí and Ribeira Orogens (SE Brazil) Guilherme Loriato Potratz, Mauro Cesar Geraldes, Edgar Batista de Medeiros Júnior, Filipe Altoé Temporim, Maria Virgínia Alves Martins Minerals, 2022 The Araçuaí and Ribeira orogens have been studied for decades, and recently, these two orogens were described as the Araçuaí–Ribeira Orogen System. Despite much work investigating this orogenic system, some issues, such as the connection between the two orogens, are still not fully understood. This work aimed to present unpublished Lu-Hf data for the Santa Angélica Intrusive Complex (SAIC) and for the host rocks that are part of the Rio Negro magmatic arc, as well as to present U-Pb ages for these rocks, thus contributing to the understanding of the geological processes that acted in the transition zone between the Araçuaí and Ribeira orogens. Two samples were collected corresponding to the magmatic arc and six samples from the Santa Angélica Intrusive Complex. The zircon grains were separated from the samples and subjected to geochronological (U-Pb) and isotopic (Lu-Hf) analysis by laser ablation-induced coupled plasma mass spectrometry (LA-ICP-MS). The geochronological data for the host rocks indicate a crystallization age of ca. 595 Ma. In contrast, the Hf isotopic data point to at least two magmatic sources, one crust, and one mantle. The geochronological data obtained for the SAIC rocks show three age peaks. The first peak (537 ± 5 Ma) coincides with the process of crustal anatexis and possibly marks the beginning of the generation of magmas associated with post-collisional magmatism. The second peak (510 ± 5 Ma) registers the apex of crystallization of the SAIC, and the third peak of ages (488 ± 7 Ma) marks the upper limit of the magmatism in the SAIC. The SAIC isotopic data point to at least two crustal components and a mantle component (juvenile).
