Repositorio Institucional Universidad EAFIT ::Examinando por Materia "Andes"

Examinando por Materia "Andes"

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Ahora es posible evitar otra tragedia por el fenómeno de La Niña
(2020-12-01) Martinez Guerrero, Christian Alexander; Christian Alexander Martinez-Guerrero; Restrepo, Juan; Kettener, Albert; Brakenridge, Robert; Vicerrectoría de Descubrimiento y Creación
Los Andes actuó como "elevador pasivo" en la diversificación de las ranas de cristal (Anura: Centrolenidae)
(Universidad EAFIT, 2020) Rueda Isaza, Yehimy Xilena; Díaz Nieto, Juan Fernando; Barrientos Correa, Lucas Santiago
Atlantic Multidecadal Oscillation (AMO) forcing on the late Holocene Cauca paleolake dynamics, northern Andes of Colombia
(Copernicus GmbH, 2015-01-01) Martínez J.I.; Obrochta S.; Yokoyama Y.; Battarbee R.W.; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
The Atlantic Multidecadal Oscillation (AMO), is a major driving climate mechanism, in the eastern Caribbean Sea and the South Atlantic Ocean in relation to the dynamics of the South American Monsoon System (SAMS) for the late Holocene. Here we document the AMO signal in the San Nicolás-1 core of the Cauca paleolake (Santa Fé-Sopetrán Basin) in the northern Andes. Wavelet spectrum analysis of the gray scale of the San Nicolás-1 core provides evidence for a 70 yr AMO periodicity for the 3750 to 350 yr BP time interval, whose pattern is analogous to the one documented for the Cariaco Basin. This supports a possible correlation between enhanced precipitation and ENSO variability with a positive AMO phase during the 2000 to 1500 yr BP interval, and its forcing role on the Cauca ria lake deposits, which led to increased precipitation and to the transition from a igapo (black water) to a varzea (white water) environment ca. 3000 yr BP. © Author(s) 2015.
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 Andrés
Comment on ‘Petrotectonic characteristics, geochemistry, and U–Pb geochronology of Jurassic plutons in the Upper Magdalena Valley-Colombia: Implications on the evolution of magmatic arcs in the NW Andes’ by Rodríguez et al. (2018)
(PERGAMON-ELSEVIER SCIENCE LTD, 2019-11-01) Bustamante C.; Cardona A.; Bustamante A.; Vanegas J.; Bustamante C.; Cardona A.; Bustamante A.; Vanegas J.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
[No abstract available]
Dynamics of species composition of small non-volant mammals from the northern Cordillera Central of Colombia
(De Gruyter, 2015-11-01) Díaz-Nieto, J.F.; Sanchez, Camilo; Universidad EAFIT. Departamento de Ciencias; Biodiversidad, Evolución y Conservación
On the basis of our recent fieldwork and historical records, we document the diversity of small non-volant mammals in the northern end of Cordillera Central of Colombia, an important region in the context of vertebrate biodiversity.
Erratum: Monitoring water discharge and floodplain connectivity for the Northern Andes utilizing satellite data: A tool for river planning and science-based decision-making (Journal of Hydrology (2020) 586, (S0022169420303474), (10.1016/j.jhydrol.2020.124887))
(ELSEVIER SCIENCE BV, 2020-01-01) Restrepo A J.D.; Kettner A.J.; Robert Brakenridge G.; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
River discharge data and magnitudes of floods are often not readily available for decision makers of many developing nations, including Colombia. And this while flooding for these regions is often devastating, causing many fatalities and insurmountable damage to the most vulnerable communities. During the wet season, in strong La Niña years, infrastructural damages of over $US 7.2 billion have occurred. Mitigation of such natural disasters lacks data-supported scientific approaches for evaluating river response to extreme climate events. Here, we propose a satellite-based technique to measure river discharge at selected sites for the main northern Andean River, the Magdalena. This method has the advantage of back calculating daily river discharges over a period of two decades, and thus making it possible to calculate return intervals of significant flood events. The study shows that satellite based river discharges well capture a) the inter-annual variability of river discharge; b) the natural seasonality of water discharge along the floodplains; and c) peak discharges that were observed during La Niña conditions between 2008 and 2011. The last is likely more accurate compared to ground-based gauging stations, as ground-based stations tend to overflow during large flood events and as such are hampered to accurately monitor peak discharges. Furthermore, we show that these derived discharges can form the base to study river-floodplain connectivity, providing environmental decision makers with a technique that makes it possible to better monitor river and ecosystem processes. © 2020 Elsevier B.V.
Evaluation of riverbank filtration in the removal of pesticides: an approximation using column experiments and contaminant transport modeling
(Springer Verlag, 2019-01-01) Jaramillo M.; Grischek T.; Boernick H.; Velez J.I.; Jaramillo M.; Grischek T.; Boernick H.; Velez J.I.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
Abstract: The potential of riverbank filtration in the removal of five pesticides commonly used in Colombia (atrazine, ametryn, carbofuran, diuron and propanil) was evaluated through a series of column experiments and solute transport modeling. The experiments consisted of two soil columns run under saturated regime, with sediments and water collected from the rivers Loessnitztal and Elbe (East Germany), respectively. Six experiments were performed at 10 and 20 °C, and the final concentrations of the pesticides were used to solve the one-dimensional advection–dispersion equation using an inverse approach. Variables such as retardation factor, first-order degradation coefficient, and dispersion coefficient were assessed for all the pesticides except propanil, which rapidly degraded in solution. The parameters obtained for one of the experiments were introduced into a groundwater flow model from the Loessnitztal site, and the code MT3DMS was used to simulate a contaminant pulse coming from the river. Four different scenarios were considered to determine the effect of adsorption and degradation on the fate of the pesticides. The results showed that, although the persistence of pesticides depends on the properties of each compound, a maximum of 30% removal was achieved during the column experiments, and a log removal of 9 through the numerical modeling. Because of the sensitivity of the fate of contaminants to sorption and degradation, field and laboratory work should be carried on to determine the removal coefficient of the dissolved and adsorbed phases of the compounds, the type of degradation to be expected, and the real values of longitudinal and transverse dispersivity. Graphical Abstract: [Figure not available: see fulltext.]. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
Geoparques en Colombia: Una estrategia para la aplicación de los objetivos de desarrollo sostenible - caso: Magdalena Medio antioqueño
(Universidad Industrial de Santander, 2019-01-01) Tavera-Escobar M.Á.; Álvarez-Ramírez D.; Tavera-Escobar M.Á.; Álvarez-Ramírez D.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
The GGN (Global Geopark Network) is a figure for the natural conservation in the rural territory through the protection, education and apropiation forms of geological resources with international importance, in conjunction with the natural and cultural context of certain sites. This work highlight methodologically the rol of the geoparks in this country and its close relationship with the Sustainable Development Goals. A case of study is proposed in Magdalena Medio antioqueño where the geological science is associated whit the economic, scientific and social development of the region by geoturism. © 2018, Universidad Industrial de Santander.
Improved gasoline-powered soft-sediment cutter
(SEPM-SOC SEDIMENTARY GEOLOGY, 2013-09-01) Sierra, Gloria M.; Marin-Ceron, Maria I.; Ramirez, Jackeline; Uribe, Camilo; Sierra, Gloria M.; Marin-Ceron, Maria I.; Ramirez, Jackeline; Uribe, Camilo; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
A device used for paleomagnetic sampling has been improved which allows sampling friable, poorly to moderate lithified sedimentary and volcanic materials. The new device attaches to a portable gasoline drill and employs two steel cutting disks with a 2 cm separation, which cuts two parallel slots in the material being sampled. A second set of cuts orthogonal to the first set produces a square pedestal over which a plastic sample box can be placed and oriented to extract a cubic sample; this procedure permits using the same orientation parameters as for conventionally drilled cylindrical samples. The method allows sampling at localities where conventional drilling fails in weak materials. To test the method, sedimentary sandstones of the Amaga' Formation (Eocene-Miocene) in the NW portion of the Central Colombian Andes were sampled. The anisotropy of magnetic susceptibility (AMS) was measured on samples using the new method and compared with results from conventionally drilled cores at the same sites. Results show better AMS within-site precision for box samples compared with the drilled cores. This device improves on previous battery-powered samplers used for sampling by the double-slot procedure. Also the new device can be used with the same gasoline-powered motor for standard core drilling. Copyright © 2013, SEPM (Society for Sedimentary Geology).
Late Quaternary vegetation and climate change in the Panama Basin: Palynological evidence from marine cores ODP 677B and TR 163-38
(ELSEVIER SCIENCE BV, 2006-05-03) Gonzalez, C; Urrego, LE; Martinez, JI; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
The Late Quaternary paleoenvironmental history from Pacific slopes of the western Andes is reconstructed by pollen analysis of 32 samples from two marine sediment cores from the Panama Basin, eastern equatorial Pacific: core ODP 677B (83°44.2200' W, 1°12.1440' N, 3473 m water depth) is 185 cm long and spans the last 39,410 years, core TR 163-38 (81.583° W, 1.337° N, 2200 m water depth) is 103 cm long and covers the last 17,380 years. Six ecological groups were established: mangrove, brackish and fresh water swamps, terra firma lowland forests, broad range taxa, Andean forests, and open vegetation. A good correspondence was found between the changes of these ecological groups in the two cores. The records evidence the continuous presence of all vegetation types during the last 39,410 years and specially the uninterrupted occurrence of tropical rain forest. They record a development from: (1) a cold and humid phase (39,410-28,120 yr cal BP) with moderately high sea levels, (2) the coldest and driest phase in the record (28,120-14,500 yr cal BP) accompanied by the lowest sea levels, (3) a transitional phase when sea level rose and humid conditions dominated, (4) a stage (11,300-5600 yr cal BP) of the highest sea levels and moisture conditions including a drier period ~7000 yr BP, to (5) a final period (5600 yr cal BP-Present) when sea level reached its present height, humidity persisted, and indicators of disturbance expanded. Peaks in pollen and spore concentration, associated with high river discharge periods, indicate periods of higher precipitation around 33,500, 28,000 and 12,000-9000 yr cal BP. Although main vegetation responses seem to reflect rainfall and moisture variations, a good correspondence was found between d18O values and percentages of Andean and lowland pollen, suggesting that vegetation also responded to tempearture changes. © 2005 Elsevier B.V. All rights reserved.
Monitoring water discharge and floodplain connectivity for the northern Andes utilizing satellite data: A tool for river planning and science-based decision-making
(ELSEVIER SCIENCE BV, 2020-07-01) Restrepo A, Juan D.; Kettner, Albert J.; Brakenridge, G. Robert; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
River discharge data and magnitudes of floods are often not readily available for decision makers of many developing nations, including Colombia. And this while flooding for these regions is often devastating, causing many fatalities and insurmountable damage to the most vulnerable communities. During the we season, in strong La Nina years, infrastructural damages of over $US 7.2 billion have occurred. Mitigation of such natural disasters lacks data-supported scientific approaches for evaluating river response to extreme climate events. Here, we propose a satellite-based technique to measure river discharge at selected sites for the main northern Andean River, the Magdalena. This method has the advantage of back calculating daily river discharges over a period of two decades, and thus making it possible to calculate return intervals of significant flood events. The study shows that satellite based river discharges well capture a) the inter-annual variability of river discharge; b) the natural seasonality of water discharge along the floodplains; and c) peak discharges that were observed during La Nina conditions between 2008 and 2011. The last is likely more accurate compared to ground-based gauging stations, as ground-based stations tend to overflow during large flood events and as such are hampered to accurately monitor peak discharges. Furthermore, we show that these derived discharges can form the base to study river-floodplain connectivity, providing environmental decision makers with a technique that makes it possible to better monitor river and ecosystem processes.
On the mathematical modelling and data assimilation for air pollution assessment in the Tropical Andes
(Springer Verlag, 2020-04-25) Quintero Montoya, O. L.; Nino-Ruiz, Elias D.; Pinel, Nicolas; Universidad EAFIT. Escuela de Ciencias; Modelado Matemático
Air pollution assessment in the Tropical Andes requires a multidisciplinary approach. This can be supported from the understanding of the underlying biological dynamics and atmospheric behavior, to the mathematical approach for the proper use of all available information. This review paper touches on several aspects in which mathematical models can help to solve challenging problems regarding air pollution in reviewing the state-of-the-art at the global level and assessing the corresponding state of development as applied to the Tropical Andes. We address the complexities and challenges that modelling atmospheric dynamics in a mega-diverse region with abrupt topography entails. Understanding the relevance of monitoring and facing the problems of data scarcity, we call attention to the usefulness of data assimilation for uncertainty reduction, and how these techniques could help tackle the scarcity of regional monitoring networks to accelerate the implementation and development of modelling systems for air quality in the Tropical Andes. Finally, we suggest a cyberphysical framework for decision-making processes based on the data assimilation of chemical transport models, the forecast of scenarios, and their use in regulation and policy making. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
Recent deforestation causes rapid increase in river sediment load in the Colombian Andes
(Elsevier Ltd, 2015-06-01) Restrepo, J.D.; Kettner, A.J.; Syvitski, J.P.M.; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
Human induced soil erosion reduces soil productivity; compromises freshwater ecosystem services, and drives geomorphic and ecological change in rivers and their floodplains. The Andes of Colombia have witnessed severe changes in land-cover and forest loss during the last three decades with the period 2000 and 2010 being the highest on record. We address the following: (1) what are the cumulative impacts of tropical forest loss on soil erosion? and (2) what effects has deforestation had on sediment production, availability, and the transport capacity of Andean rivers? Models and observations are combined to estimate the amount of sediment liberated from the landscape by deforestation within a major Andean basin, the Magdalena. We use a scaling model BQART that combines natural and human forces, like basin area, relief, temperature, runoff, lithology, and sediment trapping and soil erosion induced by humans. Model adjustments in terms of land cover change were used to establish the anthropogenic-deforestation factor for each of the sub-basins. Deforestation patterns across 1980-2010 were obtained from satellite imagery. Models were employed to simulate scenarios with and without human impacts. We estimate that, 9% of the sediment load in the Magdalena River basin is due to deforestation; 482 Mt of sediments was produced due to forest clearance over the last three decades. Erosion rates within the Magdalena drainage basin have increased 33% between 1972 and 2010; increasing the river's sediment load by 44 Mt y-1. Much of the river catchment (79%) is under severe erosional conditions due in part to the clearance of more than 70% natural forest between 1980 and 2010. © 2015 Elsevier Ltd. All rights reserved.
The San Nicolás succession of the Cauca paleolake: A late Holocene laminated ria lake record from the Neotropics
(SPRINGER, 2013-02-01) Ignacio Martinez, J.; Mayr, Christoph; Yokoyama, Yusuke; Velez, Maria I.; Battarbee, Richard W.; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
The stratigraphic, geochemical, and organic matter study of the late Holocene San Nicolás succession of the Cauca paleolake (Santa Fé-Sopetrán pull-apart basin) in the middle Cauca Valley, northern Colombia, suggests that it was deposited in a ria lake environment, at sedimentary accumulation rates in excess of 600 cm ky-1 between ~3500 and ~500 yr BP. Laminated deposition occurred, first under igapo (black-water), and then under varzea (white-water) conditions. The transition occurred ca. 3000 yr BP, a time of major change in El Niño/Southern Oscillation (ENSO) behavior in the Cariaco Basin, thus reflecting the southern migration of the intertropical convergence zone and intensified rain upstream the Cauca Valley. A second, but less conspicuous change occurred ca. 2000 yr BP, which apparently corresponds to the intensified and/or more frequent ENSO activity in the Galapagos Islands. Our contribution describes, for the first time, a ria lake sedimentary succession from the northern Andes and demonstrates the high potential of these hitherto undervalued deposits for the reconstruction of the paleohydrological history of the northern Andes. © 2012 Springer Science+Business Media Dordrecht.
Sediment yield along the Andes: Continental budget, regional variations, and comparisons with other basins from orogenic mountain belts
(ELSEVIER SCIENCE BV, 2014-07-01) Latrubesse, Edgardo M.; Restrepo, Juan D.; Universidad EAFIT. Departamento de Geología; Ciencias del Mar
We assess the sediment yield at 119 gauging stations distributed from Colombia to Patagonia, covering the different morphotectonic and morphoclimatic settings of the Andes. The most productive areas are the Meta River basin within the northern Andes and the Bolivian and northern Argentina-Chaco systems, which produce an average of 3345, 4909 and 2654tkm2 y-1 of sediment, respectively. The rivers of the northern and central Andes (excluding the Pacific watersheds of Peru, northern Chile, and central Argentina) have a weighted mean sediment yield of 2045tkm-2 y-1 and produce 2.25 GTy-1 of total sediment. A major constraint estimating the Andean continental budget of sediment yield lies in the lack of gauging data for the Peruvian region. Using the available gauge stations, the regional sediment yield appears underestimated. Assuming a higher value of sediment yield for the Peruvian Andes, the total budget for the whole central Andes could range between 2.57 GT y-1 and 3.44 GT y-1. A minimum of~0.55 GT y-1 and a probable maximum of~1.74 GT y-1 of sediment are deposited in the intramontane and surrounding proximal sedimentary basins. The magnitude of sediment yield in the Andes is comparable to other rivers draining orogenic belts around the world. © 2014 Elsevier B.V.
Tecnología satelital mide los niveles del río Magdalena
(Universidad EAFIT, 2020-12-01) Martinez Guerrero, Christian Alexander; Martinez-Guerrero, Christian Alexander; Restrepo A, Juan D.; Kettner, Albert J.; Brakenridge, G.Robert; Hidrología de los Andes del Norte
Tectonic and climate driven fluctuations in the stratigraphic base level of a Cenozoic continental coal basin, northwestern Andes
(PERGAMON-ELSEVIER SCIENCE LTD, 2008-12-01) Tamayo, J. C. Silva; Sierra, G. M.; Correa, L. G.; Tamayo, J. C. Silva; Sierra, G. M.; Correa, L. G.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
Changes in the sedimentologic and stratigraphic characteristics of the coal-bearing middle Oligocene-late Miocene siliciclastic Amagá Formation, northwestern Colombia, reflect major fluctuations in the stratigraphic base level within the Amagá Basin, which paralleled three major stages of evolution of the middle Cenozoic Andean Orogeny. These stages, which are also traceable by the changes in the compositional modes of sandstones, controlled the occurrence of important coal deposits. The initial stage of evolution of the Amagá Basin was related to the initial uplift of the Central Cordillera of Colombia around 25 Ma, which promoted moderate subsidence rates and high rates of sediment supply into the basin. This allowed the development of aggradational braided rivers and widespread channel amalgamation resulting in poor preservation of both, low energy facies and geomorphic elements. The presence of poorly preserved Alfisols within the scarce flood plains and the absence of swamp deposits suggest arid climate during this stage. The compositional modes of sandstones suggest sediment supply from uplifted basement-cored blocks. The second stage of evolution was related to the late Oligocene eastward migration of the Pre-Andean tholeitic magmatic arc from the Western Cordillera towards the Cauca depression. This generated extensional movements along the Amagá Basin, enhancing the subsidence and increasing the accommodation space along the basin. As a result of the enhanced subsidence rates, meandering rivers developed, allowing the formation of extensive swamps deposits (currently coal beds). The excellent preservation of Entisols and Alfisols within the flood plain deposits suggests rapid channels migration and a humid climate during deposition. Moderate to highly mature channel sandstones support this contention, and point out the Central Cordillera of Colombia as the main source of sediment. Enhanced subsidence during this stage also prevented channels amalgamation and promoted both, high preservation of geomorphic elements and high diversity of sedimentary facies. This resulted in the most symmetric stratigraphic cycles of the entire Amagá Formation. The final stage of evolution of the Amagá Basin was related to the early stage of development of the late Miocene northwestern Andes tholeitic volcanism (from ~10 to ~8 Ma). The extensive thrusting and folding associated to this volcanism reduced the subsidence rates along the basin and thus the accommodation space. This permitted the development of highly aggradational braided rivers and promoted channels amalgamation. Little preservation of low energy facies, poor preservation of the geomorphic elements and a complete obliteration of important swamp deposits (coal beds) within the basin are reflected by the most asymmetric stratigraphic cycles of the whole formation. The presence of greenish/reddish flood plain deposits and Alfisols suggests a dry climate during this depositional stage. The presence of channel sandstones with high contents of volcanic rock fragments supports a dry climate, and suggests an incipient phase of the Combia tholeiitic magmatism present during deposition of the Amagá Formation. The subsequent eastward migration of the NW Andes magmatic arc (after ~8 Ma) may have produced basin inversion and suppressed deposition along the Amagá Basin. © 2008 Elsevier Ltd. All rights reserved.
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 Tectónica
The 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...
U-Pb Ages and Hf Isotopes in Zircons from Parautochthonous Mesozoic Terranes in the Western Margin of Pangea: Implications for the Terrane Configurations in the Northern Andes
(UNIV CHICAGO PRESS, 2017-09-01) Bustamante C.; Archanjo C.J.; Cardona A.; Bustamante A.; Valencia V.A.; Bustamante C.; Archanjo C.J.; Cardona A.; Bustamante A.; Valencia V.A.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
U-Pb laser ablation inductively coupled plasma mass spectrometry ages and Hf isotopes in zircons were used to constrain the nature of two geological units representative of the basement of the Central Cordillera of Colombia. Graphite-quartz-muscovite schists from the Cajamarca Complex show inherited detrital zircons supplied mostly from Late Jurassic (ca. 167 Ma), Ediacaran (ca. 638 Ma), and Tonian (Grenvillian; ca. 1000 Ma) sources. These marine volcanosedimentary deposits form an N-trending metamorphic belt in fault contact to the east with orthogneisses and amphibolites of the Tierradentro unit. Zircon U-Pb determinations of the Tierradentro rockspreviously interpreted as Grenvillian basement slicesyielded crystallization ages between 271 and 234 Ma. Initial Hf data reveal that the Tierradentro unit shares isotopic characteristics similar to other Permo-Triassic rocks of the Central Cordillera. In contrast, inherited detrital zircons from the Jurassic metasedimentary rocks suggest that their sources are distinct from the plutonic rocks that crop out in the Central Cordillera with Jurassic crystallization ages. Large xenoliths of the Tierradentro unit within the Ibague batholith indicate that the granodioritic magma mostly intruded a Permo-Triassic basement possibly by exploiting the Otu-Pericos fault. The Jurassic metasedimentary belt is correlated further south with a similar sequence in the Ecuadorian Andes named Salado terrane.

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