Mineralogía y geoquímica de las menas de óxidos de Fe-Ti en la anortosita de Don Dieguito, Sierra Nevada de Santa Marta, Colombia

Fe-Ti oxide ores are commonly associated with Proterozoic massif-type anorthosite bodies emplaced during the Grenville orogeny (~1.2-1.0 Ga). Some of these anorthositic bodies occur in the northernmost part of the Santa Marta Massif, Colombia. They locally contain crosscutting Fe-Ti(-V) ore bodies between the El Hierro creek and the Don Dieguito river. We have distinguished two types of Fe-Ti(-V) ores: i) oxide-apatite norite (fine grained ilmenite and magnetite disseminated in an assemblage of apatite, amphibole, chlorite, rutile and sericitized plagioclase) and ii) banded nelsonite (coarser grained ilmenite, magnetite and apatite distributed in bands, with minor baddeleyite, srilankite and högbomite). Ilmenite in the two ore types display distinct hematite exsolution features: a) needle-like in the oxide-apatite norite ore; and b) two generations of exsolutions in the banded ore. Magnetite shows similar Ti and V contents in both ore types (0.4 wt % TiO2 and 0.5 wt % V2O3 on average in the oxide-apatite norite ore, 0.5 wt % TiO2 and 0.4 wt % V2O3 in the banded ore), whereas ilmenite has higher hematite, pyrophanite and geikielite components in the banded ore. The ores might have formed from the combination of fractional crystallization and magma mixing, with exsolution occurring probably at 575-600°C. This first detailed mineralogical and textural study of Fe-Ti(-V) oxide ores in anorthosite massifs from Colombia suggests that the Santa Marta Massif is an interesting target for future research.Las mineralizaciones de óxidos de Fe-Ti se asocian comúnmente a complejos anortosíticos proterozoicos (massif-type) emplazados durante la orogenia Grenvilliana (~1.2-1.0 Ga). Algunos de estos cuerpos anortosíticos se encuentran en la parte septentrional del Macizo de Santa Marta, en Colombia. Localmente, éstos contienen cuerpos de óxidos de Fe-Ti(-V) entre la quebrada El Hierro y el río Don Dieguito. Se han distinguido dos tipos de mineralizaciones de Fe-Ti(-V): i) norita con óxidos y apatito (ilmenita y magnetita de grano fino diseminadas en una asociación de apatito, anfíbol, clorita, rutilo y plagioclasa sericitizada); y ii) nelsonita bandeada (ilmenita, magnetita y apatito de grano grueso, distribuidos en bandas, con cantidades menores de baddeleyita, srilankita y högbomita). Las ilmenitas en los dos tipos de mineralizaciones muestran diferentes exsoluciones de hematites: con forma de aguja en la mena diseminada; y dos generaciones de exsoluciones en la mena bandeada. La magnetita presenta contenidos en Ti y V similares en ambas mineralizaciones (un promedio de 0.4 wt % TiO2 y 0.5 wt % V2O3 en la diseminada, 0.5 wt % TiO2 y 0.4 wt % V2O3 en la bandeada), mientras que la ilmenita tiene mayor componente hematites, pirofanita y geikielita en la mena bandeada. Las menas se podrían haber formado por la combinación de cristalización fraccionada y mezcla de magmas, y la exsolución tendría lugar probablemente a 575-600°C. Esta primera caracterización mineral y textural de los óxidos de Fe-Ti(-V) en macizos anortosíticos en Colombia indica que la Sierra de Santa Marta es un objetivo interesante para investigaciones futuras

Selection of Optimal Localization for a Biomass Energy Plant that Uses Residual Biomass as a Raw Material in the Araucanía Region of Chile

Residual biomass is used for energy purposes, such as producing heat and electricity. The potential raw materials are wheat, oat and barley straw, corn stover from the agricultural industry, and wood chips from forest residuals and the wood industry. In Chile about 10 MM t year−1 residues are produced; however, most of these are burned, increasing the greenhouse gas emission. This study evaluated the energy production from the residual biomass in the Araucanía Region of Chile. The optimal location for installing an energy generation plant was determined, according to various conditions, such as the distance from the villages, energy demands, industry location, etc. A multi-criteria evaluation and analytic hierarchy process were performed for determining the optimal location, and a proposal for its installation was created. A total of 19 districts were selected as suitable location that met the requirements for the three scenarios

Evaluación y diagnóstico de la resistencia a compresión y a flexión del concreto simple después de expuesto a 450°c

Trabajo de InvestigaciónMediante esta investigación se permitirá identificar de forma específica la pérdida de resistencia a compresión y flexión que sufre un elemento de concreto simple cuando sufre un evento de exposición térmica mediante conducción, que pueda servir como punto de referencia para la evaluación y diagnóstico de posibles aditivos para mitigar el efecto perjudicial de este fenómeno.1. GENERALIDADES. 2. OBJETIVOS 3. JUSTIFICACIÓN 4. DELIMITACION 5. MARCO DE REFERENCIA 6. METODOLOGIA 7. DISEÑO METODOLOGICO 8. EXPOSICIÓN DE PROBETAS A ALTAS TEMPERATURAS 9. SISTEMA DE QUEMADO 10. ENSAYOS DE PROBETAS 11. RESULTADOS 12. ANALISIS DE RESULTADOS 13. CONCLUSIONES 14. RECOMENDACIONES BIBLIOGRAFÍA ANEXOSPregradoIngeniero Civi

Metáforas y ambigüedades en la reflexión sobre Agencia, Normas y responsabilidad. Respuesta a las críticas

This article replies to the comments and criticisms made by Rocio Lorca, Matías Parmigiani, Juan Pablo Mañalich, Juan Ormeño y Flavia Carbonell to the book Adscripción y reacción. Responsabilidad jurídica y moral desde una perspectiva interpersonal. In the text, explorations are made to clarify the use of terms such as role, expectation, and obligation in the book, as well as the structure of how accountability is configured. Possible consequences of the theses advanced in the book regarding the differences between legal and moral responsibility, as well as the characterization of judgments about the attribution of responsibility, are also addressed. Finally, various aspects of the distinction between the imputation of responsibility and the imputation of actions are discussed.Este texto es una respuesta a los comentarios y críticas realizadas por Rocío Lorca, Matías Parmigiani, Juan Pablo Mañalich, Juan Ormeño y Flavia Carbonell al libro Adscripción y reacción. Responsabilidad jurídica y moral desde una perspectiva interpersonal. Se realizan exploraciones para clarificar el uso de conceptos como rol, expectativa y obligación en el libro, así como de la configuración de lo que implica responsabilizar. También se enfrentan posibles consecuencias de las tesis defendidas en el libro respecto de las diferencias entre responsabilidad jurídica y moral, así como de la caracterización de los juicios de atribución de responsabilidad. Finalmente, se discuten diversas facetas de la distinción entre atribuir responsabilidad y atribuir acciones

Landscapes Of Extraction: Capital And Nature In 21st Century Latin America

In this dissertation, I analyze the relationship between extractive capitalism and ecological crisis in a series of novels and documentary films from contemporary Latin America. Focusing on novels such as Roberto Bolaño’s 2666 (2004), Lina Meruane’s Fruta Podrida (2007), Samanta Schweblin’s Distancia de Rescate (2014), Juan Cárdenas’ El diablo de las provincias (2017), and documentary films such as Patricio Guzmán’s Nostalgia de la luz (2010) and El botón de nácar (2015), I show how an uncontrolled wave of resource extraction, also known as neo-extractivism, unfolded in Latin American countries during the authoritarian and neoliberal governments that followed the revolutionary struggles of the Sixties and Seventies, and provoked reforms that led to the systemic privatization of nature and labor through political and economic violence. Drawing on a Marxist critique of capitalist ecologies and ecocriticism, this dissertation makes three key claims. First, I argue that resource extraction is the other side of the free-market economy, in that by forcibly separating resources and goods from their environment, particularly in indigenous territories and borderlands, it makes them available as commodities to be traded. Second, I contend that the violence of neo-extractivism provokes a crisis in the aesthetic representation of the landscape and its project to organize social and natural relations, which leads to narratives of environmental catastrophe that contradict ideas of progress and development. Finally, I show that due to Latin America’s role as a source of exports in the world-system, the region’s artistic production not only reveals the intimate relation between extractivism and neoliberalism, but also allows us to visualize the symbolic articulations that emerge from the fracture between human and non-human nature in the peripheries of global capital