900 resultados para The Xiangshan U deposit
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Introducción: La evaluación de programas sociales, ha sido, desde sus inicios, de gran importancia para fortalecer los procesos de toma de decisiones de los hacedores de los programas, ya que retroalimenta lo ejecutado y ayuda a aplicar correctivos necesarios para lograr el impacto deseado en la población objetivo, que generalmente son comunidades vulnerables como las personas con discapacidad. En los últimos años, esta población ha sido foco de múltiples programas y proyectos en diferentes temáticas como la actividad física, la recreación, el deporte y la educación física. Por esto, en el año 2013, Coldeportes en aras de poder parametrizar y permitir un impacto adecuado en esta población, diseñó un grupo de lineamientos los cuales son los encargados de generar las directrices de los programas que se diseñen y ejecuten en los entes territoriales. Para poder realizar el seguimiento y resultado de su aplicación, es necesario hacerlo por intermedio de una herramienta de evaluación. De acuerdo con las últimas tendencias en la evaluación de programas sociales, debe hacerse por intermedio de indicadores, los cuales permiten realizarla de una manera más eficiente. Por tal motivo, la herramienta de evaluación para los lineamientos será a través de indicadores. Objetivo: Generar una herramienta de evaluación para los programas y actividades en actividad física, recreación y deporte para la población con discapacidad en Colombia, a partir de los lineamientos de inclusión definidos por Coldeportes. Metodología: Se realizó una revisión bibliográfica acerca de la evaluación de programas sociales, indicadores de evaluación y población con discapacidad, seguido a esto se diseñaron los indicadores de evaluación con base en las variables de los lineamientos propuestos por Coldeportes, posteriormente, los indicadores fueron sometidos a una validación en un grupo nominal, conformado por expertos en programas sociales y trabajo en población con discapacidad, por último, se sistematizaron y analizaron los resultados. iii Resultados: La herramienta de evaluación fue validada por parte de los expertos, hubo ajustes en los indicadores de evaluación de los lineamientos de accesibilidad a la comunicación e información, accesibilidad a la formación académica y accesibilidad al entorno físico. Conclusiones: La herramienta de evaluación diseñada, es un primer paso para mejorar los métodos actuales de evaluación, encaminada a fortalecer los datos existentes de la población con discapacidad y tener una visión del impacto de los planes, programas y proyectos en actividad física, recreación y deporte ejecutados en la actualidad, por lo cual queda continuar con la investigación en nuevas alternativas de evaluación que permitan mejorar los procesos de toma de decisiones y así garantizar planes, programas y proyectos sociales adecuados para la población, sin distinguir características particulares.
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El presente trabajo de grado busca exponer el panorama actual de la exploración y producción de hidrocarburos en Yacimientos No Convencionales, realizada utilizando el fracturamiento hidráulico – Fracking – cómo método para lograr mejores condiciones físicas en el reservorio que permitan la extracción del recurso. El método mencionado es estudiado a la luz de los principios de prevención, precaución y desarrollo sostenible, que rigen la política ambiental en Colombia, con el objetivo de analizar los posibles impactos ambientales y sociales que se puedan generar por el desarrollo de la actividad extractiva de hidrocarburos en Yacimientos No Convencionales. Para finalmente mostrar que el Fracking como actividad está legalmente permitida en Colombia, y la legislación vigente responde a los principios mencionados previamente.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Caxias é um depósito de ouro orogênico do fragmento cratônico São Luís, que é correlacionável aos terrenos Riacianos do Cráton Oeste-Africano. O depósito se formou após o metamorfismo regional (estimado em 2100 ± 15 Ma) e está hospedado em zona de cisalhamento que secciona xistos do Grupo Aurizona (2240 ± 5 Ma) e o Microtonalito Caxias. O microtonalito foi aqui datado em 2009 ± 11 Ma, e representa um estágio magmático tardio na evolução do fragmento cratônico São Luís. Cristais de zircão com idades de 2139 ± 10 Ma foram herdados da fonte magmática ou são produto de contaminação durante a intrusão. A composição dos isótopos de chumbo sugere que granitoides de arco de ilhas de ca. 2160 Ma são a fonte provável para o Pb incorporado na pirita relacionada com o minério. Sericita hidrotermal mostra idade up>40up>Ar/up>39up>Ar de 1990 ± 30 Ma, que, combinada com a idade de posicionamento do microtonalito hospedeiro, limita o evento mineralizador ao intervalo 2020-1960 Ma.
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"Compiled to supersede and bring up to date the previous edition, published in 1940."
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On cover: National bank laws as of Jan. 1, 1936
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ELA-ICP-MS U-Pb zircon geochronology has been used to show that the porphyritic intrusions related to the formation of the Bajo de la Alumbrera porphyry Cu-Au deposit, NW Argentina, are cogenetic with stratigraphically well-constrained volcanic and volcaniclastic rocks of the Late Miocene Farallon Negro Volcanic Complex. Zircon geochronology for intrusions in this deposit and the host volcanic sequence show that multiple mineralized porphyries were emplaced in a volcanic complex that developed over 1.5 million years. Volcanism occurred in a multivent volcanic complex in a siliciclastic intermontane basin. The complex evolved from early mafic-intermediate effusive phases to a later silicic explosive phase associated with mafic intrusions. Zircons from the basal mafic-intermediate lavas have ages that range from 8.46 +/- 0.14 to 7.94 +/- 0.27 Ma. Regionally extensive silicic explosive volcanism occurred at similar to8.0 Ma (8.05 +/- 0.13 and 7.96 +/- 0.11 Ma), which is co-temporal with intrusion of the earliest mineralized porphyries at Bajo de la Alumbrera (8.02 +/- 0.14 and 7.98 +/- 0.14 Ma). Regional uplift and erosion followed during which the magmatic-hydrothermal system was probably unroofed. Shortly thereafter, dacitic lava domes were extruded (7.95 +/- 0.17 Ma) and rhyolitic diatremes (7.79 +/- 0.13 Ma) deposited thick tuff blankets, across the region. Emplacement of large intermediate composition stocks occurred at 7.37 +/- 0.22 Ma, shortly before renewed magmatism occurred at Bajo de la Alumbrera (7.10 +/- 0.07 Ma). The latest porphyry intrusive event is temporally associated with new ore-bearing magmatic-hydrothermal fluids. Other dacitic intrusions are associated with subeconomic deposits that formed synchronously with the mineralized porphyries at Bajo de la Alumbrera. However, their emplacement continued (from 7.10 +/- 0.06 to 6.93 +/- 0.07 Ma) after the final intrusion at Bajo de al Alumbrera. Regional volcanism had ceased by 6.8 Ma (6.92 +/- 0.07 Ma). The brief history of the volcanic complex hosting the Bajo de la Alumbrera Cu-Au deposit differs from that of other Andean provinces hosting porphyry deposits. For example, at the El Salvador porphyry copper district in Chile, magmatism related to Cu mineralization was episodic in regional igneous activity that occurred over tens of millions of years. Bajo de la Alumbrera resulted from the superposition of multiple porphyry-related hydrothermal systems, temporally separated by a million years. It appears that the metal budget in porphyry ore deposits is not simply a function of their longevity and/or the superposition of multiple porphyry systems. Nor is it a function of the duration of the associated cycle of magmatism. Instead, the timing of processes operating in the parental magma body is the controlling factor in the formation of a fertile porphyry-related ore system.
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The Vazante Group, located in the northwestern part of Minas Gerais, hosts the most important zinc mine in Brazil, the Vazante Mine, which represents a major known example of a hypogene nonsulfide zinc deposit. The main zinc ore is represented by willemite and differs substantially from other deposits of the Vazante-Paracatu region, which are sulfide-dominated zinc-lead ore. The age of the Vazante Group and the hosted mineralization is disputable. Metamorphosed mafic dikes (metabasites) that cut the metasedimentary sequence and are affected by hydrothermal processes recently were found and may shed light on the geochronology of this important geological unit. Zircon crystals recovered from the metabasites are xenocrystic grains that yield U-Pb conventional ages ranging from 2.1 to 2.4 Ga, so the basement of the Vazante Group is Paleoproterozoic or has metasedinientary rocks whose source area was Paleoproterozoic. Pb isotopes determined for titanite separated from the metabasites have common, nonradiogenic Ph compositions, which prevents determination of their crystallization age. However, the Pb signatures observed for the titanite crystals are in agreement with those determined for galena from the carbonate-hosted Zn-Pb deposits hosted by the Vazante Group, including galena from minor sulfide ore bodies of the Vazante deposit. These similarities suggest that the metalliferous fluids that affected the metabasites may have been those responsible for galena formation, which could imply a similar lead source for both nonsulfide and sulfide zinc deposits in the Vazante-Paracatu district. This common source could be related to deep-seated, basin-derived, metalliferous fluids associated with a long-lived hydrothermal system related to diagenesis and deformation of the Vazante Group during the Neoproterozoic. (c) 2005 Elsevier Ltd. All rights reserved.
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Groundwater samples were collected for several months in boreholes drilled at Morro do Ferro, a thorium and rare earth deposit located on the Poços de Caldas Plateau, Minas Gerais State, Brazil. An aquifer system has developed in the weathered mantle due to in situ intense alteration. The weathered zone includes a thick argillaceous laterite greater than 100 m thick. The U content and 324U/238U activity ratio were measured in the groundwater samples and in spoil samples of a borehole drilled in the ore body. Some possible mechanisms related to the mobilization of uranium are considered such as complexation with humic substances and adsorption by clays. © 1989.
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A manganese oxide crust from an extensive deposit in the median valley of the Mid-Atlantic Ridge was found to be unusually high in manganese (up to 39.4% Mn), low in Fe (as low as 0.01% Fe), low in trace metals and deficient in Th230 and Pa231 with respect to the parent uranium isotopes in the sample. The accumulation rate is 100 mm to 200 mm/10 million year, or 2 orders of magnitude faster than the typical rate for deep-sea ferromanganese deposits. The rapid growth rate and unusual chemistry are consistent with a hydrothermal origin or with a diagenetic origin by manganese remobilized from reduced sediments. Because of the association with an active ridge, geophysical evidence indicative of hydrothermal activity, and a scarcity of sediment in the sampling area, we suggest that a submarine hot spring has created the deposit.