cometadata/datacite-titles-descriptions-related-identifiers huggingface dataset:
DOI: 10.6084/m9.figshare.7518131
title: Laterites of the Coreaú Mid-Domain - geochemistry behavior of lateritic mantles in the Northwest of Ceará State

description: In this paper an evaluation is made over the geochemistry signature of major elements in lateritic rocks on the counties of Granja, Martinópole and Parazinho, Northwest of Ceará State. Geologically, the area is located in Médio Coreaú Domain, characterized by the Granja Complex, which is the geological basement of the region, composed by gneiss, granulites and migmatites, and supracrustal sequences formed by quartizites and phyllites of Martinópole and Ubajara Group, and also cenozoic sediments of Barreiras Formation. Laterites are normally found in humid weather (seasonal or not), so it is more likely that the generation process of this lateritic beds were under ancient climatic conditions, totally different from the present. The laterites are associated with gneiss, quartzites and phyllites. The prevailing laterization process is the metal enrichment, especially iron. Iron content varies from 34.69 to 77.85% in the altered rock samples; this trend being more evident in gneiss, in which iron enrichment exceeds 75%. Al content increases 6 to 7% in altered rocks. Sm-Nd data showed that the ratios obtained in these laterites are similar to the protoliths and can be used to define autochthonous from allocththounus laterites and also confirm Sm and Nd mobility in the laterization process.
DOI: 10.6084/m9.figshare.7518131.v1
title: Laterites of the Coreaú Mid-Domain - geochemistry behavior of lateritic mantles in the Northwest of Ceará State

description: In this paper an evaluation is made over the geochemistry signature of major elements in lateritic rocks on the counties of Granja, Martinópole and Parazinho, Northwest of Ceará State. Geologically, the area is located in Médio Coreaú Domain, characterized by the Granja Complex, which is the geological basement of the region, composed by gneiss, granulites and migmatites, and supracrustal sequences formed by quartizites and phyllites of Martinópole and Ubajara Group, and also cenozoic sediments of Barreiras Formation. Laterites are normally found in humid weather (seasonal or not), so it is more likely that the generation process of this lateritic beds were under ancient climatic conditions, totally different from the present. The laterites are associated with gneiss, quartzites and phyllites. The prevailing laterization process is the metal enrichment, especially iron. Iron content varies from 34.69 to 77.85% in the altered rock samples; this trend being more evident in gneiss, in which iron enrichment exceeds 75%. Al content increases 6 to 7% in altered rocks. Sm-Nd data showed that the ratios obtained in these laterites are similar to the protoliths and can be used to define autochthonous from allocththounus laterites and also confirm Sm and Nd mobility in the laterization process.
DOI: 10.6084/m9.figshare.7508027
title: The chromium and copper-nickel mineralized Várzea do Macaco body, Jacurici Mafic-ultramafic Complex, São Francisco Craton, Bahia, Brazil

description: The Jacurici Mafic-ultramafic Complex, located in the northeastern portion of the São Francisco craton, consists of several N-S oriented layered bodies that host the largest chromite deposit in Brazil. The Várzea do Macaco body is at the northern part and also host a Ni-Cu sulfide mineralization. This study describes this body and its mineralization and compare with the southern intrusions (Ipueira-Medrado) where a petrological evolution was previous established. The Várzea do Macaco is stratigraphically inverted and disrupted in five blocks, laterally dislocated by late faults. It is constituted by dunite, lherzolite, ol-webesterite, chromitite and gabbronorite with variable serpentinization. The sulfide ore (Po ± Pn ± Cpy) is concentrated close to the main thick chromitite layer and occurs as: primary magmatic with interstitial sulfides associated with olivine and pyroxene; and as a remobilized ore, with sulfides associated to metasomatic veinlets or lenses that crosscut the primary layering. The interval where magmatic ores occur is characterized by the presence of magmatic amphibole that possible favoured late metamorphism and metasomatism transformation, stronger in this interval. The remobilized sulfide is enriched in chalcopyrite showing an increase in the Cu/Ni ratio. Comparing to Ipueira-Medrado, the Várzea do Macaco is enriched in clinopyroxene, but it can be subdivided in the same Ultramafic and Mafic zones. Possibly, both bodies are part of a single intrusive system characterized by a primitive magma with high Mg and Ni contents. The chromite mineralization is considered to be triggered by crustal contamination. At Várzea do Macaco, sulfur saturation was reached.
DOI: 10.6084/m9.figshare.7508027.v1
title: The chromium and copper-nickel mineralized Várzea do Macaco body, Jacurici Mafic-ultramafic Complex, São Francisco Craton, Bahia, Brazil

description: The Jacurici Mafic-ultramafic Complex, located in the northeastern portion of the São Francisco craton, consists of several N-S oriented layered bodies that host the largest chromite deposit in Brazil. The Várzea do Macaco body is at the northern part and also host a Ni-Cu sulfide mineralization. This study describes this body and its mineralization and compare with the southern intrusions (Ipueira-Medrado) where a petrological evolution was previous established. The Várzea do Macaco is stratigraphically inverted and disrupted in five blocks, laterally dislocated by late faults. It is constituted by dunite, lherzolite, ol-webesterite, chromitite and gabbronorite with variable serpentinization. The sulfide ore (Po ± Pn ± Cpy) is concentrated close to the main thick chromitite layer and occurs as: primary magmatic with interstitial sulfides associated with olivine and pyroxene; and as a remobilized ore, with sulfides associated to metasomatic veinlets or lenses that crosscut the primary layering. The interval where magmatic ores occur is characterized by the presence of magmatic amphibole that possible favoured late metamorphism and metasomatism transformation, stronger in this interval. The remobilized sulfide is enriched in chalcopyrite showing an increase in the Cu/Ni ratio. Comparing to Ipueira-Medrado, the Várzea do Macaco is enriched in clinopyroxene, but it can be subdivided in the same Ultramafic and Mafic zones. Possibly, both bodies are part of a single intrusive system characterized by a primitive magma with high Mg and Ni contents. The chromite mineralization is considered to be triggered by crustal contamination. At Várzea do Macaco, sulfur saturation was reached.
DOI: 10.21227/t84t-v603
title: Forecast Result for January 29

description: This csv file contains the load forecasts result, conducted by Hongqiao Peng.
DOI: 10.6084/m9.figshare.7506941
title: Geology of the Riacho do Pontal iron oxide copper-gold (IOCG) prospect, Bahia, Brazil: hydrothermal alteration approached via hierarchical cluster analysis

description: The Riacho do Pontal prospect is situated on the border between the Borborema Province and the São Francisco Craton, in Bahia state. It comprises rocks polydeformed during the Neoproterozoic. The prospect area includes migmatites and gneissic rocks intruded by several sin- to post-tectonic granites. Structural analysis indicates a strong relationship between the development of ductile to brittle-ductile shear zones and associated hydrothermalism. The main tracts of high-strain rate are represented by the Riacho do Pontal (north) and Macururé (south) shear zones. Several copper occurrences have been mapped within the Riacho do Pontal prospect along secondary shear zones. In these areas, the gneissic rocks were affected by intense hydrothermal alteration. Hierarchical cluster analysis permitted the identification of the main hydrothermal mineral associations present in these rocks, which resulted from potassic (biotite) and sodic-calcic (amphibole-albite) alteration, in addition to silicification and iron alteration (hematite). These hydrothermal alteration types are similar to those typically found in iron oxide copper-gold deposits developed at intermediate crustal levels. Hematite-quartz-albite-chalcopyrite-pyrite hydrothermal breccias host the highest-grade copper ore (chalcopyrite-pyrite-chalcocite) zones. The spatial relationship between copper deposits and shear zones improves the metallogenic potential for copper of the Borborema Province and has important implications for mineral exploration in the region.
DOI: 10.6084/m9.figshare.7506941.v1
title: Geology of the Riacho do Pontal iron oxide copper-gold (IOCG) prospect, Bahia, Brazil: hydrothermal alteration approached via hierarchical cluster analysis

description: The Riacho do Pontal prospect is situated on the border between the Borborema Province and the São Francisco Craton, in Bahia state. It comprises rocks polydeformed during the Neoproterozoic. The prospect area includes migmatites and gneissic rocks intruded by several sin- to post-tectonic granites. Structural analysis indicates a strong relationship between the development of ductile to brittle-ductile shear zones and associated hydrothermalism. The main tracts of high-strain rate are represented by the Riacho do Pontal (north) and Macururé (south) shear zones. Several copper occurrences have been mapped within the Riacho do Pontal prospect along secondary shear zones. In these areas, the gneissic rocks were affected by intense hydrothermal alteration. Hierarchical cluster analysis permitted the identification of the main hydrothermal mineral associations present in these rocks, which resulted from potassic (biotite) and sodic-calcic (amphibole-albite) alteration, in addition to silicification and iron alteration (hematite). These hydrothermal alteration types are similar to those typically found in iron oxide copper-gold deposits developed at intermediate crustal levels. Hematite-quartz-albite-chalcopyrite-pyrite hydrothermal breccias host the highest-grade copper ore (chalcopyrite-pyrite-chalcocite) zones. The spatial relationship between copper deposits and shear zones improves the metallogenic potential for copper of the Borborema Province and has important implications for mineral exploration in the region.
DOI: 10.6084/m9.figshare.7509596
title: Aeromagnetic and physical-chemical properties of some complexes from Goiás Alkaline Province

description: The Goiás Alkaline Province (GAP), located on the north edge of the Paraná Basin, has alkaline complexes with strong magnetic signatures. The 3D inversion of magnetic signal was performed on the aeromagnetic data. Since the intrusions present a strong remnant magnetization, as measured in the laboratory, a careful analysis of this component was also realized. The sum vector of the remnant and induced components were used as a virtual induced magnetic field during the 3D inversion process. The geometric parameters were obtained from the quantitative analysis of magnetic data, using Total Gradient Direction and Analytical Signal Phase, performed over magnetic signal reduced to the pole. Magnetic susceptibility and density were measured in laboratory. All this information were used as the initial model in the inversion. The results of 3D inversion show that the alkaline intrusions have roots up to 10-12 km depth. The magnetic susceptibility is distributed in almost spherical and cylindrical shapes. The possibility of spherical shapes arise the hypothesis that the GAP intrusions at the northern part of the province represent magmatic chambers. The alkaline magma ascends from the lithosphere, and used two main fault systems as space for emplacement. These faults systems appear in the magnetic signal analysis as linear magnetic features. Chemical analysis confirmed the alkaline and subalkaline character of the magmas. The high MgO content shows the primitive character of these intrusions but the Ba anomaly indicates a possible crustal contamination.
DOI: 10.6084/m9.figshare.7509596.v1
title: Aeromagnetic and physical-chemical properties of some complexes from Goiás Alkaline Province

description: The Goiás Alkaline Province (GAP), located on the north edge of the Paraná Basin, has alkaline complexes with strong magnetic signatures. The 3D inversion of magnetic signal was performed on the aeromagnetic data. Since the intrusions present a strong remnant magnetization, as measured in the laboratory, a careful analysis of this component was also realized. The sum vector of the remnant and induced components were used as a virtual induced magnetic field during the 3D inversion process. The geometric parameters were obtained from the quantitative analysis of magnetic data, using Total Gradient Direction and Analytical Signal Phase, performed over magnetic signal reduced to the pole. Magnetic susceptibility and density were measured in laboratory. All this information were used as the initial model in the inversion. The results of 3D inversion show that the alkaline intrusions have roots up to 10-12 km depth. The magnetic susceptibility is distributed in almost spherical and cylindrical shapes. The possibility of spherical shapes arise the hypothesis that the GAP intrusions at the northern part of the province represent magmatic chambers. The alkaline magma ascends from the lithosphere, and used two main fault systems as space for emplacement. These faults systems appear in the magnetic signal analysis as linear magnetic features. Chemical analysis confirmed the alkaline and subalkaline character of the magmas. The high MgO content shows the primitive character of these intrusions but the Ba anomaly indicates a possible crustal contamination.
DOI: 10.6084/m9.figshare.7516529
title: Influence of Brazilian structures on the reservoir induced seismicity case of Irapé Hydroelectric Plant, Minas Gerais, Brazil

description: Inaugurated in 2006, the Irapé Hydroelectric Plant has the highest dam in Brazil, with 210 m. The Seismological Observatory of the University of Brasilia is monitoring this structure since the beginning of its reservoir filling. The reservoir triggered seismicity caused by the increase of crustal tension just after the start of the remains like an important object of study for understanding this phenomenon. This paper aims at studying the seismicity recorded from January to May 2006, as well as to characterize the geology around the Hydroelectric Plant Irapé in order to identify and describe the structures that help for better understanding the seismic events. The spatial orientation of the seismic events obtained by analyzing polarity and waveform is consistent with the guidance of prominent relief lineaments. These faults can be found attached to a larger structure with main NE/SW direction and tens of kilometers, which would be responsible for capturing Jequitinhonha and Araçuaí rivers. This great lineament is interpreted herein as a structure related to a late stage of the Brasiliano-Panafrican event. The solution of focal mechanism, created using an inversion method of the waveform in the time domain, indicates that the direction of the possible plans are correlated to main failure of brittle structures targeting the area of work.
DOI: 10.6084/m9.figshare.7516529.v1
title: Influence of Brazilian structures on the reservoir induced seismicity case of Irapé Hydroelectric Plant, Minas Gerais, Brazil

description: Inaugurated in 2006, the Irapé Hydroelectric Plant has the highest dam in Brazil, with 210 m. The Seismological Observatory of the University of Brasilia is monitoring this structure since the beginning of its reservoir filling. The reservoir triggered seismicity caused by the increase of crustal tension just after the start of the remains like an important object of study for understanding this phenomenon. This paper aims at studying the seismicity recorded from January to May 2006, as well as to characterize the geology around the Hydroelectric Plant Irapé in order to identify and describe the structures that help for better understanding the seismic events. The spatial orientation of the seismic events obtained by analyzing polarity and waveform is consistent with the guidance of prominent relief lineaments. These faults can be found attached to a larger structure with main NE/SW direction and tens of kilometers, which would be responsible for capturing Jequitinhonha and Araçuaí rivers. This great lineament is interpreted herein as a structure related to a late stage of the Brasiliano-Panafrican event. The solution of focal mechanism, created using an inversion method of the waveform in the time domain, indicates that the direction of the possible plans are correlated to main failure of brittle structures targeting the area of work.
DOI: 10.6084/m9.figshare.7510601
title: Geology, petrology, U-Pb (shrimp) geochronology of the Morrinhos granite -Paraguá terrane, SW Amazonian craton: implications for the magmatic evolution of the San Ignácio orogeny

description: Morrinhos granite is a batholith body that is slightly elongated in the NNW direction and approximately 1,140 km2 long; it is located in the municipality of Vila Bela da Santíssima Trindade of the state of Mato Grosso, Brazil, in the Paraguá Terrane, Rondonian-San Ignácio Province, in the SW portion of the Amazonian Craton. This intrusion displays a compositional variation from tonalite to monzogranite, has a medium to coarse inequigranular texture and is locally porphyritic; biotite is the predominant mafic in one of the facies, and hornblende is predominant in the other, with both metamorphosed into the greenschist facies. The studied rocks characterize an intermediate to acidic sequence that was formed by a subalkaline magmatism; the series is alkali-calcic to metaluminous to slightly peraluminous, and the rocks evolved through fractioned crystallization mechanisms. The structural data show two deformation phases represented by penetrative foliation (S1) and open folds (D2), and both phases were most likely related to the San Ignácio Orogeny. The geochronological (U-Pb SHRIMP) and isotopic (Sm-Nd) investigations of these rocks indicated a crystallization age of 1350 ± 12 Ma, TDMof approximately 1.77 Ga and εNd(1.35)with a negative value of -2.57, suggesting that their generation was related to a partial melting process of a Paleoproterozoic (Statherian) continental crust. The results herein indicate that the Morrinhos granite was generated in a continental magmatic arc in a late- to post-orogenic stage of the San Ignácio Orogeny, and it can be recognized as belonging to the Pensamiento Intrusive Suite.
DOI: 10.6084/m9.figshare.7510601.v1
title: Geology, petrology, U-Pb (shrimp) geochronology of the Morrinhos granite -Paraguá terrane, SW Amazonian craton: implications for the magmatic evolution of the San Ignácio orogeny

description: Morrinhos granite is a batholith body that is slightly elongated in the NNW direction and approximately 1,140 km2 long; it is located in the municipality of Vila Bela da Santíssima Trindade of the state of Mato Grosso, Brazil, in the Paraguá Terrane, Rondonian-San Ignácio Province, in the SW portion of the Amazonian Craton. This intrusion displays a compositional variation from tonalite to monzogranite, has a medium to coarse inequigranular texture and is locally porphyritic; biotite is the predominant mafic in one of the facies, and hornblende is predominant in the other, with both metamorphosed into the greenschist facies. The studied rocks characterize an intermediate to acidic sequence that was formed by a subalkaline magmatism; the series is alkali-calcic to metaluminous to slightly peraluminous, and the rocks evolved through fractioned crystallization mechanisms. The structural data show two deformation phases represented by penetrative foliation (S1) and open folds (D2), and both phases were most likely related to the San Ignácio Orogeny. The geochronological (U-Pb SHRIMP) and isotopic (Sm-Nd) investigations of these rocks indicated a crystallization age of 1350 ± 12 Ma, TDMof approximately 1.77 Ga and εNd(1.35)with a negative value of -2.57, suggesting that their generation was related to a partial melting process of a Paleoproterozoic (Statherian) continental crust. The results herein indicate that the Morrinhos granite was generated in a continental magmatic arc in a late- to post-orogenic stage of the San Ignácio Orogeny, and it can be recognized as belonging to the Pensamiento Intrusive Suite.
DOI: 10.6084/m9.figshare.7513811
title: Geochemistry and geochronology U-Pb Shrimp of granites from Peixoto de Azevedo: Alta Floresta Gold Province

description: The analysis of petrographic, geochemical and geochronological data of granites in the Peixoto de Azevedo region, Mato Grosso, Brazil, in the eastern portion of the Alta Floresta Gold Province, led to the recognition of two granitic bodies bounded by regional major faults and shear zones. In the northwestern portion a body with featured as biotite granodiorite, coarse-grained, with porphyritic to inequigranular texture, metaluminous to peraluminous, high-K calc-alkaline and magnesium character. In the southeastern portion of the area, a biotite monzogranite coarse-grained, with equigranular to porphyritic texture, slightly peraluminous, high-K calc-alkaline and dominantly of ferrous character. U- Pb dating (SHRIMP) showed that the biotite monzogranite has an age of 1869 ± 10 Ma, similar to the Matupá Intrusive Suite, while the biotite granodiorite has an age of 1781 ± 10 Ma, that is the age expected to Peixoto Granite. Both units show patterns of rare earth elements with enrichment of light over heavy and negative Eu anomaly (LaN/YbN " 7.6 to 17.31 and ratios Eu/Eu* between 0.46 - 0.72 for biotite monzogranite and LaN/YbN " 7.13 to 29.09 with ratios Eu/Eu* between 0.25 - 0.40 for the biotite granodiorite). Trace elements pattern for both present negative anomalies of Ba, P, Ti and Nb indicating an evolution from mineral fractionation and subduction related sources. In this paper, it is sugested that the monzogranite Matupá was developed in mature arc tectonic environment. For the Peixoto Granite, two hypotheses are suggested: (a) it was developed in younger magmatic arc environment associated with the Colider Magmatism or (b) it was generated in extentional tectonic environment during the Columbia Supercontinent break up.