Examinando por Materia "Petrografía"
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Ítem Características petrográficas y de alteración hidrotermal en litotipos asociados a sistemas magmático-hidrotermales tipo pórfido en los Andes y el Cratón amazónico : estudio del caso Chuscal (Colombia), Pegasus (Ecuador), Antamina (Perú), Las Tórtolas (Chile) y Provincia Mineral de Tapajós (Brasil)(Universidad EAFIT, 2021) Malagón Quiroga, Daniel Esteban; Saa Calderón, Andrés Felipe; Gómez Gutierréz, Diego Felipe; Jiménez Torres, Carlos AndrésÍtem Caracterización petrográfica del proyecto ABE GOLD en el Norte de la Cordillera Central, municipio de Abejorral(Universidad EAFIT, 2022) Correa Cardona, Wilfredo; Bustamante Londoño, Camilo; Gómez Gutiérrez, Diego FelipeÍtem Caracterización petrológica con énfasis en microestructuras aplicado a rocas milonitizadas a la altura de la quebrada Sinifaná – Antioquia(Universidad EAFIT, 2023) Calero Castaño, Julián Armando; Duque Trujillo, José FernandoThe petrographic analysis and microstructural characteristics allow us to know in greater detail the mineralogy, alterations and structures associated with tectonic processes that affect the minerals in the rock. The present work is located near the village of Bolombo, on the right bank of the Sinifaná stream, and inside a tributary stream of the basin. Here we observe the development of a shear zone that affects the Sabaletas Schists and places them in contact with the Quebradagrande Complex. In order to understand this shear zone, a mineralogical characterization was carried out, based on petrography with emphasis on the microstructures, defining a protomylonite, which involves rock fragments and disaggregated minerals of quartz and plagioclase, fractured with microfaulting and a diversity in the porphyroclasts, S'-C type microstructures and recrystallization processes, which allowed estimating possible evolutionary environments, as well as offering a correlation with the lineament proposed by Peláez (2020) where the present shear zone is developed, related to the Cauca-Almaguer Fault System.Ítem Distribución de Allanita en el Stock de Mariquita y su posible origen(Universidad EAFIT, 2022) Romero Muñoz, Katherin; Bustamante Londoño, CamiloÍtem Modelamiento geológico - estructural del Pórfido (Cu-Mo) Don Javier, Arequipa, Perú(Universidad EAFIT, 2020) Barragan Salinas, Adolfo Osmin; Muñoz Muñoz, Mac Yimerson; Marín Cerón, Maria Isabel; Chuquimia Pacheco, Gino EnmioÍtem Petrografía y geoquímica de las rocas volcánicas de la FM. Saldaña y su relación con el Batolito de Ibagué(Universidad EAFIT, 2019) Benavides Castrillón, Laura Andrea; Bustamante Londoño, CamiloÍtem Petrographic and litho-geochemical characterization of the VMS deposit at El Roble mine, Colombian Western Cordillera(Universidad Eafit, 2020) Murillo Bedoya, José Manuel; Marín Cerón, María Isabel; Echeverri Franco, BalmerEl Roble Mine (Cu-Au) siliciclastic-mafic volcanogenic massive sulfide (VMS) deposit, is located at El Carmen de Atrato, Chocó, Colombian Western Cordillera. This 4-million-ton VMS occurs replacing black chert rocks between Upper Cretaceous volcanic Barroso Formation and Upper Cretaceous Urrao member of Penderisco Formation. Major, trace and REE elements, indicate that there are at least two different mantle sources (E-MORB and N-MORB) from the volcanic Barroso Formation(?). Then the close relation between black chert unit and E-MORB related basalts may have leaded the VMS mineralization. The 2D geochemical vector modelling from drill-cores around “Zeus” ore body shows positive correlated anomalies for the AI (Alteration Index), CCPI (Chlorite Carbonate Pyrite Index), Tl and MgO with the presence of hyaloclastites, becoming important exploration vectors for the VMS at the North Volcanic Zone of the Andean Cordillera. Nevertheless, the Na2O negative anomaly close to the ore body, is not conclusive in such type of VMS due to overprinted hydrothermal alteration closely related to the Cenozoic arc environment.Ítem Pore Structure Characteristics and Gas Storage Potential of the Cretaceous La Luna Formation, Middle Magdalena Valley Basin, Colombia(Universidad EAFIT, 2020-06-19) Casadiego-Quintero, Efraín; Rios-Reyes, Carlos Alberto; Fundación Universitaria Agraria de Colombia; Universidad Industrial de SantanderThe rocks of interest in the present study (mudstones) show inherently a heterogeneous pore-size distribution in the matrix. They can present organic and inorganic pores and the transport mechanism through pores is different, and, therefore, it is necessary to describe their organic and inorganic porosity. This work uses different microscopy techniques to characterize mudstones from the Galembo Member of the Cretaceous La Luna Formation, Middle Magdalena Valley Basin, Colombia. These rocks present several pore types, including interparticle pores due to flocculation of clay minerals, organoporosity due to burial and thermal maturity, intraparticle pores from organisms, intraparticle pores within mineral grains, and microchannels and microfractures. The existence of interconnected pores in such complex fracture-pore system provides effective pathways for primary gas migration and it also provides a storage space for the residual hydrocarbon in mudstones, which is important for the primary migration and storage in gas reservoir rocks. The pore connectivity is high and increases towards the top of the sedimentary sequence.Ítem Sedimentary signatures in Jambaló Blueschist : Tectonic implications(Universidad Eafit, 2023) Rodríguez Arango, Daniel; Bustamante Londoño, CamiloThe aim of this contribution is to analyze the sedimentary influence on the protoliths that gave rise to the blue schists of Jambaló, Cauca, Colombia, through the detailed identification of their mineralogical and structural characteristics. The hypothesis posits that the protolith of the Jambaló blue schists exhibits significant signs of a sedimentary component, which may reflect the proximity of an oceanic arc to the western margin of South America during the Cretaceous period. Fieldwork and petrographic analyses were conducted to characterize the blue and green schists in the area. Previous geochemical data were also reanalyzed. The results indicate that both types of schists share a common origin but followed distinct metamorphic paths. Geochemistry suggests a mixture of pelagic and terrigenous sediments in the protoliths, with a higher proportion of pelagic sediments. This supports the hypothesis of the proximity of an oceanic arc that accumulated these sediments. In conclusion, the Jambaló blue schists represent a metamorphic belt distinct from those previously proposed for the region. Their protoliths reflect the approach of an intra-oceanic arc to the continental margin during the Cretaceous.