Examinando por Materia "Groundwater"
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Ítem Groundwater Physicochemical Characteristics’ Analysis of Chicú River Basin, Colombia, Using Hydrochemical Indicators and Multivariate Statistics(Universidad EAFIT, 2018-11-23) López Velandia, Cristian Camilo; Corporación Unificada Nacional de Educación SuperiorÍtem The Paleogene arcs of the northern Andes of Colombia and Panama: Insights on plate kinematic implications from new and existing geochemical, geochronological and isotopic data(ELSEVIER SCIENCE BV, 2018-12-06) Cardona A.; León S.; Jaramillo J.S.; Montes C.; Valencia V.; Vanegas J.; Bustamante C.; Echeverri S.; Cardona A.; León S.; Jaramillo J.S.; Montes C.; Valencia V.; Vanegas J.; Bustamante C.; Echeverri S.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaThe northern Andes of Colombia comprise two non-cogenetic Paleogene arcs formed in contrasting geodynamic settings including continental and oceanic domains. New whole-rock geochemistry and isotopic constraints, together with a review of 332 geochemical, 76 isotopic and 204 geochronological data from Paleocene to Eocene volcanic and plutonic rocks exposed in central and western Colombia and Panama, are used to evaluate cause-effect relations between regional plate kinematics and the spatio-temporal distribution of the circum-Caribbean magmatic arcs. Short-lived, ~60–45 Ma arc-like magmatism in the Central Cordillera of Colombia was emplaced in a thickened continental crust due to the oblique subduction of the Caribbean oceanic plate underneath South America, as suggested by the high Sr/Y ratios. Conversely, the Panama Arc, and its poorly explored extension in the northwestern segment of the Western Cordillera of Colombia document a major phase of tholeiitic to calc-alkaline arc magmatism between ~71 Ma and ~34 Ma, mostly derived from a hydrated mantle wedge, and emplaced in an oceanic plateau crust. This arc record a major phase of magmatic activity between 40 Ma and 50 Ma that can be associated to changes in the convergence direction and subduction rates of the Farallon plate. Farther to the south, in the Pacific region of Colombia, Eocene arc-related rocks from the Timbiqui Complex show a geochemical signature that suggests a magmatic origin from melting of both a subduction-modified mantle and lower tectonically thickened crust. A possible interpretation for the Pacific and Western Colombia-Panama Arc systems, and its analogous in Ecuador, recall an Aleutian-type convergent margin in which the continental arc laterally switches to a purely oceanic system along the trailing edge of the Caribbean plate as consequence of eastward subduction of the Farallon plate. © 2018 Elsevier B.V.Ítem Vulnerabilidad intrínseca a la contaminación del Sistema Acuífero del Altiplano Nariñense aplicando el método GOD(Universidad EAFIT, 2023) Patarroyo Barragán, Laura Lucía; Enríquez Hidalgo, Laura Sofía; Jaramillo Uribe, MarcelaThe capacity of an aquifer to be contaminated depends on its intrinsic properties, that is the possibility of substances entering on it, due to hydraulic properties of the overlying lithology. The main cause of contamination is given by anthropogenic activities on the surface. The Altiplano Nariñense Aquifer System (SAAN) is influenced by geomorphological features that allow the recharge of the system, from this, it was proposed that the infiltration of polluting loads is correlated with the topography. To estimate vulnerability, geological, hydrogeological information and water points sampled in 2005-2006 were collected, which allowed us to apply the GOD method that involves three parameters related to the type of aquifer, lithology of the unsaturated zone and depth of groundwater. Three of the five vulnerability indices proposed by this method were evident, associated to the classification “very low”, “medium” and “high”, where medium vulnerability predominates with 51.09% of the total area. Because the main use of land in the Altiplano Nariñense (AN) is for agriculture and this activity requires agrochemicals, there is a probability that these are the main contaminants, and it is also evident that a part of the surface water system has a high index of potential alteration of water quality and its interaction with the aquifer system would also contribute to the dispersion of contaminants. The result was compared with the vulnerability map with the land cover map in the AN, which indicates that 88.44% is destinated to agricultural territories.