Examinando por Autor "Duque-Trujillo, J.F."
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Ítem Geomorphological Features of the Galeras Volcanic Complex(SPRINGER, 2016-01-01) Calvache, M.L.; Duque-Trujillo, J.F.; Calvache, M.L.; Duque-Trujillo, J.F.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaThe Galeras volcanic complex, near the city of Pasto, was formed in several steps. At similar to 560 ka, BP a major caldera (the Coba Negra Caldera) appeared with its center similar to 5 km west of the present-day active volcano top. This caldera was 5 km in diameter and elongated in the E-W direction. The wall of the subsequent Jenoy caldera is covered by glacial morphology indicating a pre-glacial (Ítem The Guamuez (La Cocha) Lake(SPRINGER, 2016-01-01) Duque-Trujillo, J.F.; Hermelin, M.; Toro, G.E.; Duque-Trujillo, J.F.; Hermelin, M.; Toro, G.E.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaThe Guamuez Lake (also called La Cocha) lies at 2765 m a.s.l. southeast of Pasto. La Corota, its main island, houses a wildlife sanctuary of endemic species protected by the Ministry of the Environment. The La Cocha valley and its neighbor the Sibundoy valley (similar, but completely drained lake) are both seated along one of the main strike-slip faults, the Algeciras fault. This fault system borders the Northern Andes in southwestern Colombia, forming valleys along its trace due to local pull-apart stress associated to its movements. Several small volcanic structures are aligned over the main fault traces which limit the tectonic valleys, making La Cocha a unique landscape. The vegetation that could be found around La Cocha is also unique, because it represents one of the altitudinal lowest paramo ecosystems in the world.Ítem Magnetic biomonitoring as a tool for assessment of air pollution patterns in a tropical valley using Tillandsia sp.(MDPI AG, 2018-07-01) Mejía-Echeverry, D.; Chaparro, M.A.E.; Duque-Trujillo, J.F.; Chaparro, M.A.E.; Miranda, A.G.C.; Mejía-Echeverry, D.; Chaparro, M.A.E.; Duque-Trujillo, J.F.; Chaparro, M.A.E.; Miranda, A.G.C.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaRecently, air pollution alerts were issued in the Metropolitan Area of Aburrá Valley (AVMA) due to the highest recorded levels of particulate matter (PM2.5 and PM10) ever measured. We propose a novel methodology based on magnetic parameters and an epiphytic biomonitor of air pollution in order to improve the air pollution monitoring network at low cost. This methodology relies on environmental magnetism along with chemical methods on 185 Tillandsia recurvata specimens collected along the valley (290 km2). The highest magnetic particle concentrations were found at the bottom of the valley, where most human activities are concentrated. Mass-specific magnetic susceptibility (?) reaches mean (and s.d.) values of 93.5 (81.0) and 100.8 (64.9) × 10-8 m3 kg-1 in areas with high vehicular traffic and industrial activity, while lower ? values of 27.3 (21.0) × 10-8 m3 kg-1 were found at residential areas. Most magnetite particles are breathable in size (0.2-5 µm), and can host potentially toxic elements. The calculated pollution load index (PLI, based on potentially toxic elements) shows significant correlations with the concentration-dependent magnetic parameters (R = 0.88-0.93; p < 0.01), allowing us to validate the magnetic biomonitoring methodology in high-precipitation tropical cities and identify the most polluted areas in the AVMA. © 2018 by the authors.Ítem Timing of rifting in the southern Gulf of California and its conjugate margins: Insights from the plutonic record(Geological Society of America, 2015-05-01) Duque-Trujillo, J.F.; Duque-Trujillo, J.F.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y TectónicaThe Gulf of California is a young example of crustal stretching and transtensional shearing leading to the birth of a new oceanic basin at a formerly convergent margin. Previous studies focused along the southwestern rifted margin in Baja California...