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Sample records for cordillera domeyko antofagasta

  1. Transcurrencia a lo largo de la Falla Sierra de Varas (Sistema de fallas de la Cordillera de Domeyko, norte de Chile Strike-slip along the Sierra de Varas Fault (Cordillera de Domeyko Fault-System, northern Chile

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    Hans Niemeyer

    2009-01-01

    Full Text Available El Sistema de Fallas de la Cordillera de Domeyko, de rumbo esencialmente norte-sur, es paralelo a la fosa chileno-peruana en el norte de Chile. Se analizaron los desplazamientos en el rumbo y en la vertical de una de sus fallas maestras: la Falla Sierra de Varas (FS V. Ésta se estudió en el segmento entre Aguada del Hornito y Aguada del Cerro Alto de Varas, sobre la base del desplazamiento en el rumbo de dos porciones de la unidad de Granitoides paleozoicos con idéntica petrografía, estructura interna y edad. Se determinó una separación sinistral horizontal de 15,6±1 km con una componente vertical de 4,9±0,1 km, lo cual implica un rechazo neto sinistral-inverso de 16,4±1 km. El alzamiento vertical está de acuerdo con el espesor estratigráfico erosionado del bloque oriental. Se investigó, además, la dinámica y cinemática de la FS V mediante el análisis de mesofallas asociadas a sus desplazamientos. Se determinó así un sistema estructural sinistral-inverso, que tuvo lugar durante el Eoceno medio tardío. Un segundo sistema estructural dextral, con desplazamiento de 0,6 km se sobrepuso sobre el anterior y ocurrió con posterioridad al Mioceno. Los desplazamientos simultáneos, tanto en el rumbo como según fallas inversas, dados por la existencia de una 'flor inversa en el segmento estudiado, indican que éste fue afectado primeramente por una transpresión. El desplazamiento sinistral demostrado paralaFSVy su cambio de rumbo hacia el SE, inmediatamente al sur de Aguada de Alto de Varas, son compatibles con la vergencia hacia el oeste de pliegues y fallas inversas asociadas del cinturón plegado y corrido de El Profeta, el cual también habría resultado de la transpresión.The north-south trending Cordillera de Domeyko Fault System in northern Chile considered herein is parallel to the Peru-Chile trench. The displacement history of the Sierra de Varas Fault, a master fault of the mentioned system, was examined in detall in the

  2. Late Mesozoic to Paleogene stratigraphy of the Salar de Atacama Basin, Antofagasta, Northern Chile: Implications for the tectonic evolution of the Central Andes

    Science.gov (United States)

    Mpodozis, Constantino; Arriagada, César; Basso, Matilde; Roperch, Pierrick; Cobbold, Peter; Reich, Martin

    2005-04-01

    The Salar de Atacama basin, the largest "pre-Andean" basin in Northern Chile, was formed in the early Late Cretaceous as a consequence of the tectonic closure and inversion of the Jurassic-Early Cretaceous Tarapacá back arc basin. Inversion led to uplift of the Cordillera de Domeyko (CD), a thick-skinned basement range bounded by a system of reverse faults and blind thrusts with alternating vergence along strike. The almost 6000-m-thick, upper Cretaceous to lower Paleocene sequences (Purilactis Group) infilling the Salar de Atacama basin reflects rapid local subsidence to the east of the CD. Its oldest outcropping unit (Tonel Formation) comprises more than 1000 m of continental red sandstones and evaporites, which began to accumulate as syntectonic growth strata during the initial stages of CD uplift. Tonel strata are capped by almost 3000 m of sandstones and conglomerates of western provenance, representing the sedimentary response to renewed pulses of tectonic shortening, which were deposited in alluvial fan, fluvial and eolian settings together with minor lacustrine mudstone (Purilactis Formation). These are covered by 500 m of coarse, proximal alluvial fan conglomerates (Barros Arana Formation). The top of the Purilactis Group consists of Maastrichtian-Danian alkaline lava and minor welded tuffs and red beds (Cerro Totola Formation: 70-64 Ma K/Ar) deposited during an interval of tectonic quiescence when the El Molino-Yacoraite Late Cretaceous sea covered large tracts of the nearby Altiplano-Puna domain. Limestones interbedded with the Totola volcanics indicate that this marine incursion advanced westwards to reach the eastern CD slope. CD shortening in the Late Cretaceous was accompanied by volcanism and continental sedimentation in fault bounded basins associated to strike slip along the north Chilean magmatic arc to the west of the CD domain, indicating that oblique plate convergence prevailed during the Late Cretaceous. Oblique convergence seems to have

  3. La Cordillera Oriental Colombiana, Transecto Sumapaz

    NARCIS (Netherlands)

    Hammen, van der T.; Rangel, J.O.; Cleef, A.M.

    2008-01-01

    The publication of this volume (volume 7) concludes the publication of the study of the Transects of Buritaca (Sierra Nevada de Santa Marta), Parque Los Nevados (Cordillera Central), Tatamá (Western Cordillera) and Sumapaz (Eastern Cordillera) in the Colombian Andes. The latter three studies

  4. Best practices of the SME mining suppliers in the Antofagasta region of Chile

    OpenAIRE

    Miguel Atienza; Patricio Aroca; Robert Stimson; Roger Stough

    2013-01-01

    In regions whose industrial structure is organized around one or more large firm corporations, the best practices of small and medium enterprises (SMEs) depend on where firms are located in the supply chain. This paper studies 351 SMEs in the Antofagasta Region in Chile between 2007 and 2008, where multinational and public mining companies are the drivers of the local economy and the government is promoting the formation of a mining cluster. Structural equation model (SEM) is used to show tha...

  5. A Critical Assessment and Projection of Urban Vertical Growth in Antofagasta, Chile

    OpenAIRE

    Massimo Palme; José Guerra Ramírez

    2013-01-01

    Vertical cities’ growth is argument of discussion worldwide. Population increases and a better soil use are needed, in terms of efficiency and density, in many cities of the world. However, an excessive vertical growth seems to be harmful, especially near the green areas of midtowns. In this paper, the case of Antofagasta is studied. The paper studies different possible future evolutions searching for a bearable development, respecting the society needs and the environment. Parameters analyze...

  6. Rocky intertidal zonation pattern in Antofagasta, chile: invasive species and shellfish gathering.

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    Juan Carlos Castilla

    Full Text Available BACKGROUND: Biological invasions affecting rocky intertidal zonation patterns, yield information on species interactions. In the Bay of Antofagasta, northern Chile, the non-indigenous tunicate Pyura praeputialis, originally from Australia, has invaded (in the past century or so and monopolized a major portion of the mid-intertidal rocky shore, displacing upshore the native mussel Perumytilus purpuratus. In Antofagasta the tunicate is subjected to intensive exploitation. Monitoring protocols show that in the past 10 years Antofagasta's tunicate population has experienced a drastic decline, affecting the intertidal zonation pattern. METHODOLOGY/PRINCIPAL FINDINGS: A 12.5 km of coastline, on the southern eastern shore of the Bay of Antofagasta, was studied. Eight sites were systematically (1993-1994 or sporadically (2003-2014 monitored for the seaward-shoreward expansion or reduction of the tunicate Pyura praeputialis, and native mussel and barnacle bands. A notable reduction in the mid-intertidal band of P. praeputialis and a seaward expansion of the mussel, Perumytilus purpuratus, and barnacle bands was observed. We suggest that the major cause for the decline in the tunicate is due to its intensive exploitation by rocky shore Pyura-gathers. The rate of extraction of tunicates by professional Pyura-gathers ranged between 256-740 tunicates hour-(1. Between 2009-2014 the density of professional Pyura-gather ranged between 0.5-4.5 km(-1 per low tide. Hence, 10 professional Pyura-gathers working 1 h for 10 low tides per month, during 6 months, will remove between 307-888 m(2 of tunicates. A drastic decline in tunicate recruitment was observed and several P. praeputialis ecosystems services have been lost. CONCLUSION AND SIGNIFICANCE: In Antofagasta, the continuous and intensive intertidal gathering of the invasive tunicate Pyura praeputialis, has caused a drastic reduction of its population modifying the zonation pattern. Thereby, native mussel

  7. ACERCA DE LA FLORA DE ANTOFAGASTA DE LA SIERRA, CATAMARCA, ARGENTINA. AMBIENTE Y PALEOAMBIENTE

    OpenAIRE

    M. Fernanda Rodríguez

    2013-01-01

    Se presenta una síntesis de los trabajos realizados sobre la identificación, anatomía y usos de especies vegetales, actuales y recuperadas en el marco de las investigaciones arqueobotánicas, llevadas a cabo en Antofagasta de la Sierra durante las campañas arqueológicas realizadas en los años 1994-2000. Se describen las transectas realizadas a partir de los sitios arqueológicos estudiados, las asociaciones vege- tales características y se presenta un listado de las especies vegetales halladas....

  8. Migración y representaciones regionales: discursos sobre la Región de Antofagasta

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    Luis Miguel Rodrigo

    2014-05-01

    Full Text Available El estudio de la migración interna se ha basado tradicionalmente en una concepción banal del espacio, sin tener en cuenta cómo las representaciones regionales, el espacio construido socialmente, afectan la decisión de migrar a otra región. Este trabajo utiliza las metodologías del grupo de discusión y el análisis sociológico del discurso para identificar los discursos de los futuros profesionales de otras regiones de Chile sobre la Región de Antofagasta, área minera localizada en el norte del país. A pesar de la prosperidad creciente de esta región durante las dos últimas décadas, los discursos que la representan poseen una denotación negativa, con distintos rasgos según la distancia socioespacial a esta región y el género del hablante. Estas representaciones podrían limitar la llegada de migrantes calificados y mujeres a Antofagasta y afectar negativamente el desarrollo futuro de la región.

  9. A Critical Assessment and Projection of Urban Vertical Growth in Antofagasta, Chile

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    José Guerra Ramírez

    2013-06-01

    Full Text Available Vertical cities’ growth is argument of discussion worldwide. Population increases and a better soil use are needed, in terms of efficiency and density, in many cities of the world. However, an excessive vertical growth seems to be harmful, especially near the green areas of midtowns. In this paper, the case of Antofagasta is studied. The paper studies different possible future evolutions searching for a bearable development, respecting the society needs and the environment. Parameters analyzed are: temperature, humidity, solar radiation, wind speed and direction in the studied area. Results show the impact of building growth in terms of overheating and wind reduction on the ground area studied. Additionally, the social impact of living in towers is also discussed in the paper, searching for better design in order to guarantee user’s comfort, satisfaction and stimulation in their residences. Thermal, visual and acoustical effects produced by towers are considered in the critical evaluation of the Antofagasta city evolution. Part of this work relates to architectural workshop “energy and architecture” conducted by the authors at the School of Architecture of the Catholic University of the North (UCN in 2012.

  10. TECNOLOGÍA DE CAZA EN LA QUEBRADA DE ANTOFALLA, DEPARTAMENTO ANTOFAGASTA DE LA SIERRA, CATAMARCA / Hunting technology in the Antofalla Valley, Antofagasta de la Sierra Department, Catamarca.

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    Enrique Alejandro Moreno

    2011-12-01

    Full Text Available Las prácticas de cacería de camélidos silvestres han sido relevantes para la reproducción de las poblaciones humanas en los Andes Centro-Sur durante los últimos 12000 años aproximadamente. Para la materialización de esta práctica, son relevantes las armas utilizadas para poder dar muerte a las presas pretendidas. Una alternativa para interpretar el tipo de arma es a través de la información obtenida del análisis de las puntas de proyectil líticas registradas mediantes metodologías disciplinarias. Como caso de estudio utilizamos los datos obtenidos de la prospección intensiva y sistemática desarrollada en la quebrada de Antofalla, ubicada en el Departamento Antofagasta de la Sierra, Provincia de Catamarca, Argentina. Para evaluar las características de esta tecnología nos centraremos en tres grandes aspectos: las características tecno-morfológicas de estos instrumentos, la asignación a distintos tipos de armas y sus posibles asignaciones cronológicas, los espacios donde fueron registrados estos especímenes, en relación con las características de los paisajes cinegéticos.   Palabras clave: Tecnología; cacería; camélidos; armas; paisaje.   Abstract The hunting practice of wild camelids has been relevant for the reproduction of human populations in the South Central Andes for the last 12000 years. An important aspect for the materialization of this practice, are the weapons used in order to kill the alleged preys. In this paper we shall introduce the different weapons used by human populations, mainly, through the information obtained from the analysis of of lithic projectile points. As a case study we will retake the information obtained from the intensive and systematic prospection developed at the Antofalla ravine, located in the Departamento Antofagasta de la Sierra, Provincia de Catamarca. In order to evaluate the features of this technology, we will focus on three aspects: the techno-morphological characteristics

  11. Cacao 3 (Cc 3, Arte rupestre del formativo temprano en Antofagasta de la Sierra, Catamarca, Argentina

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    Alvaro Rodrigo Martel

    2004-01-01

    Full Text Available En el presente trabajo hemos abordado el estudio de la producción del arte rupestre del sitio Cacao 3 –Cc3- (Antofagasta de la Sierra, Catamarca con relación a las prácticas socioculturales de grupos agropastoriles del periodo Formativo Temprano en la Puna meridional argentina, haciendo hincapié en el emplazamiento del sitio y su asociación contextual con las demás evidencias arqueológicas conocidas para el área de estudio y estableciendo las relaciones entre las manifestaciones rupestres de Cc3 con las de otros sitios, a nivel micro y macrorregional, a través de indicadores estilísticos

  12. Otredad racializada en la migración forzada de afrocolombianos a Antofagasta (Chile

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    María Margarita Echeverri B.

    2016-01-01

    Full Text Available El artículo constata que Chile se ha consolidado como destino de afrodescendientes del Pací - ico colombiano en los últimos años. Desde las especiicidades de esta red migratoria, analiza las particularidades del desplazamiento forzado internacional de la población colombiana en Antofagasta, la reconiguración de las representaciones que recaen sobre ésta y su relación con la producción de discursos políticos y sociales racializados y sexualizados. Concluye que éstos últimos actúan como políticas de enunciación restrictivas de las prácticas transnaciona - les y la incorporación social y cultural a ambos lados de la frontera.

  13. La cordillera oriental colombiana no se desprende de la cordillera central

    OpenAIRE

    Ujueta, Guillermo

    2012-01-01

    Geologically the Central and Eastern Cordilleras depict different periods of genesis and different types of rocks which allow them to keep their identities and independence from Colombia to Bolivia; however, in the area of study are connected by a bridge formed by a recent geomorphollogical feature which is the result of combined tectonic and volcanic stresses which took place toward the end of the Pliocene. This bridge has a direction NW-SE and connects the Cutanga Volcanoe on the Central Co...

  14. Cordillera Blanca: glaciares en la historia

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    1995-01-01

    Full Text Available CORDILLERE BLANCHE - DES GLACIERS DANS L’HISTOIRE. La plus vaste couverture glaciaire de l’entre-tropiques n’apparaît comme un objet d’études que très tard, à la fin du XIXème siècle et, surtout grâce aux expéditions austro-allemandes, à partir des années 1930-1940. Le développement de l’alpinisme et un grand nombre de catastrophes meurtrières associées à la dynamique de ces glaciers (rupture de lacs de barrage morainique, avalanches ont attiré l’attention sur eux et suscité des recherches glaciologiques. En 1980, ils comptent parmi les mieux surveillés des glaciers tropicaux, d’abord grâce à un programme d’étude développé par les Péruviens eux-mêmes. à un moment où le réchauffement global fait craindre un recul très important de la glaciation dans la zone tropicale, les glaciers de la Cordillère Blanche deviennent d’excellents indicateurs de l’évolution climatique en cours et la ressource en eau qui leur est associée constitue à la fois un sujet d’étude et un enjeu économique de haute importance. La más vasta cobertura glaciar situada entre los trópicos aparece como objeto de estudio relativamente tarde, a fines del siglo XIX, sobre todo gracias a las expediciones austro alemanas a partir de los años 1930-1940. El desarrollo del alpinismo y un gran número de catástrofes mortales asociadas a la dinámica de estos glaciares (rotura de lagunas de represa morrénica, avalanchas atrajeron la atención y suscitaron investigaciones glaciológicas. En 1980, se encuentran entre los mejor monitoreados de los glaciares tropicales, primero, gracias a un programa de estudio desarrollado por los peruanos. En un momento en que el recalentamiento global hace temer un retroceso muy importante de la glaciación en la zona tropical, los glaciares de la Cordillera Blanca se convierten en excelentes indicadores de la evolución climática en curso y el recurso hídrico que se les asocia constituye a la vez un tema

  15. Drug interactions in HIV patients treated in a high complexity hospital of Antofagasta city

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    Patricio R. Araya

    2017-11-01

    Full Text Available Context: From the beginning of the global HIV epidemic there has been a great concern about drug interactions (DI considering that up to 27% of all patients may be affected by at least one type of DI, this risk increases by receiving concomitant treatments. This DI leads to negative consequences such as adverse drug reactions (ADR, lack of treatment adherence and new hospital admissions. Aims: To determine the prevalence of DI of antiretroviral drugs and their clinical consequences in UNACESS-VIH-SIDA patients of Hospital Regional de Antofagasta. Methods: The study included a total of 100 HIV patients. To identify DI, Micromedex database was used. All data were gathered in a pharmaceutical datasheet, the theoretical DI were identified and real DI were detected by using hematologic tests and the patient’s clinical evolution. After the detection of any real DI, a pharmaceutical intervention took place. Results: A total of 106 DI were detected; 86% of DI found were related to drug’s pharmacokinetic properties, which were mostly metabolism related interactions (96.9%; the most commonly found associations were atazanavir with ritonavir, efavirenz with atorvastatin and efavirenz with gemfibrozil. The main clinical consequences associated with DI were ADR (49%. Conclusions: High prevalence of metabolism-related interactions was found and the antiretroviral drugs mostly associated with DI were found to be atazanavir, ritonavir y efavirenz. A high prevalence of ADR was found; however, they were mild or moderate.

  16. ACERCA DE LA FLORA DE ANTOFAGASTA DE LA SIERRA, CATAMARCA, ARGENTINA. AMBIENTE Y PALEOAMBIENTE

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    M. Fernanda Rodríguez

    2013-01-01

    Full Text Available Se presenta una síntesis de los trabajos realizados sobre la identificación, anatomía y usos de especies vegetales, actuales y recuperadas en el marco de las investigaciones arqueobotánicas, llevadas a cabo en Antofagasta de la Sierra durante las campañas arqueológicas realizadas en los años 1994-2000. Se describen las transectas realizadas a partir de los sitios arqueológicos estudiados, las asociaciones vege- tales características y se presenta un listado de las especies vegetales halladas. Se describe el uso actual y se señala el nombre vernáculo para cada taxón. Luego, se presenta una descripción anatómica de tallo, raíz u hoja, dependiendo del caso, de cada uno de los taxones presentes en los sitios arqueológicos, identificados por medio de la comparación anatómica con material actual de referencia; se presentan las correspondientes fotomicrografías obtenidas con microscopio óptico y/o microscopio electrónico de barrido. Finalmente, se discute el uso, en la actualidad y en el pasado, de las especies recuperadas en los sitios arqueológicos del área de estudio, destacando aquellos aspectos que suponen cambio y continui- dad a través del tiempo.

  17. Pharmaceutical intervention in menopausal patients with hormone replacement therapy in a community pharmacy from Antofagasta

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    Alejandrina Alucema

    2015-02-01

    Full Text Available Context: Hormone replacement therapy (HRT is the most widely used treatment for controlling the effects of menopause. This type of therapy causes some drug-related problems (DRP, which requires monitoring to control the negative effects and ensure patient adherence to therapy. Aims: Perform a pharmacotherapeutic monitoring and educate to menopausal patients in HRT of a community pharmacy from the city of Antofagasta. Methods: A 98-menopausal patients underwent a pharmaceutical intervention to identify the PRM and its resolution. It was applied to them a survey before and after educational activities about this disease and HRT to determine the knowledge on the subject. Results: During the pharmacotherapeutic monitoring was determined that 55% of patients using combined HRT. 62 DRPs were detected, of which 43 were resolved (69%; the most were Patient-Pharmacist (73%. The better resolution DRP were DRP 4(b “frequency of inadequate administration” and DRP 2(a “no medical indication”. At baseline, 90% had an inadequate level of knowledge about the disease and THR, 8% intermediate, and only 2% adequate. After the implementation of the education strategy, the level of knowledge increased, achieving at the end of the study only intermediate (10% and adequate (90% levels. Conclusions: The results confirm the importance of pharmaceutical intervention for the identification and resolution of DRP and the requirement to establish educational strategies to increase the knowledge about menopause and HRT in menopausal patients.

  18. Patterns of self-medication in customers of a community pharmacy in the Antofagasta city

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    Alejandrina Alucema

    2013-12-01

    Full Text Available Context: Self-medication is the use of unprescribed drugs; this means that people obtain drugs on their own initiative and without the assistance of health professionals. This is an increasingly common practice among the population that can cause numerous problems, becoming a public health problem. Aims: To determine the patterns of self-medication in customers who frequented a community pharmacy in the city of Antofagasta. Methods: A survey was conducted to 297 users over 18 years and with adequate mental and communicative power to answer the questions, and attending the pharmacy to buy a drug without a prescription. Results: The study revealed that of the 297 people who practiced self-medication, 41% do it with a frequency of at least once a month. The woman practiced in 64% and the men in 36%. The range of age of the studied group was between 31-50 years. The main reason to practice the self medication was to recognize symptoms (33%, within the most notable was the headache (11%. The therapeutic group of the most requested medicines was the NSAIDs (20%, and of them the paracetamol was the most used. Conclusions: The results reveal that a high percentage of customers surveyed self-medicate, which shows this practice as a real problem, so it is necessary to educate people.

  19. First record of Cymatium keenae Beu, 1970 (Mollusca: Ranellidae) from Antofagasta Bay, northern Chile, in connection with El Niño events

    Science.gov (United States)

    Ashton, Tom; Riascos, Jose M.; Pacheco, Aldo

    2008-03-01

    Cymatium ( Monoplex) keenae Beu, 1970, the neopolitan triton, is a Ranellidae predator distributed in tropical and subtropical waters. In this study we report this species for the first time in Antofagasta Bay, northern Chile. Adult specimens have been found since June 2003 at depths ranging from 5 to 15 m in La Rinconada Marine Reserve (23°28'18″S, 70°30'46″W) in Antofagasta Bay, near a scallop farming facility. The present findings clearly extend the geographic range of C. keenae, which previously had been reported from La Paz, Gulf of California (Mexico) to Galápagos Islands (Ecuador) in the SE Pacific. Previous evidence strongly suggests that the intrusion of this tropical immigrant can be related to warm El Niño episodes. We analyze the key role of the oceanographic characteristics of Antofagasta Bay as potential temporal refuge for this species.

  20. Innovative potential of small and medium-sized enterprises in the Antofagasta-Chile region: an exploratory study

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    Gianni A. Romani Chocce

    2006-10-01

    Full Text Available The aim of this research is to analyze the innovative potential of Small and Medium Enterprises (SMEs in the Region of Antofagasta - Chile. The paper makes a detailed bibliographic revision on regional innovation processes and presents the results of a questionnaire applied to SMEs, considered as innovative according to the Organization for Economic Co-operation and Development (OCDE criteria. Although these results have to be carefully considered, due to the size of the sample it is possible to observe that there is an increasing awareness of the importance of innovation in the region while, at the same time, many obstacles to innovate are recognized.

  1. Muerte fetal in utero, etiología y factores asociados en el hospital regional de antofagasta, Chile

    OpenAIRE

    Jeannette Linares-Moreno; Rodrigo Madariaga-Alvarez; Ronald Poulsen

    2006-01-01

    Introducción: El objetivo del presente estudio fue determinar la etiología y los factores maternos asociados de las muertes fetales intrauterinas; ocurridas después de las 20 semanas de gestación. Materiales y métodos: Se realizó un estudio descriptivo retrospectivo de las muertes; fetales intrauterinas acontecidas en un período de 2 años (2004-2006) en el Hospital Clínico Regional de Antofagasta. Resultados: Se; encontraron 50 casos de muerte fetal después de las 20 semanas de gesta...

  2. Muerte Fetal In Útero: Etiología y factores asociados en un Hospital Regional de Antofagasta, Chile

    OpenAIRE

    Jeannette Linares; Ronald Poulsen

    2007-01-01

    Objetivos: Conocer la etiología y los factores maternos asociados a las muertes fetales intrauterinas ocurridas después de las; veinte semanas de gestación. Diseño: Estudio descriptivo. Lugar: Servicio de Ginecología y Obstetricia del Hospital Clínico; Regional de Antofagasta. Participantes: Muertes fetales intrauterinas ocurridas en mujeres embarazadas a partir de las veinte; semanas de gestación, cuyos partos fueron atendidos en el hospital. Intervenciones: Revisión del libro de in...

  3. Escuela bioclimática y sustentable : Secundaria nº 39 - Villa de Antofagasta de la Sierra - Catamarca

    OpenAIRE

    Waler, Érika; Agüero, Matías; Watkins, María Gabriela; Mansilla, Gabriela

    2016-01-01

    En este trabajo se presenta el proyecto y la construcción de una escuela realizada en la Villa de Antofagasta de la Sierra (latitud: -26°06’, longitud: 67°41’ y altura sobre el nivel del mar: 3440mts), localidad ubicada en la provincia de Catamarca, de clima árido andino puneño, con grandes amplitudes térmicas y altos niveles de irradiación solar. La imagen de la Villa, en su conjunto, preserva los valores culturales y patrimoniales de los lugareños. El objetivo de éste proyecto es utilizar e...

  4. Indicadores nutricionales en la población infanto-juvenil de Antofagasta de la Sierra, Catamarca

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    Lomaglio, Delia Beatriz

    2003-01-01

    Full Text Available Antofagasta de la Sierra está ubicada en el NO de la provincia de Catamarca en la región de Puna, a alturas superiores a 3000 metros sobre el nivel del mar. Con el objeto de conocer el estado nutricional de la población infanto- juvenil se obtuvieron las medidas de peso y estatura, las que fueron convertidas a puntajes z y se calcularon los índices P/E, T/E y P/T. Los índices nutricionales fueron comparados con las tablas del NCHS. Se observó prevalencia alta de baja talla y prevalencia... de bajo peso. Si bien es conocido el efecto de la hipoxia de alturas extremas sobre el crecimiento, en el caso de Antofagasta de la Sierra se asocian otros factores, en general presentes también en otras poblaciones de altura, como condiciones sanitarias, socio-económicas y nutricionales deficitarias y que dificultan el análisis.

  5. Landsat TM and ETM+ derived snowline altitudes in the Cordillera Huayhuash and Cordillera Raura, Peru, 1986–2005

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    J. Ramage

    2011-05-01

    Full Text Available The Cordilleras Huayhuash and Raura are remote glacierized ranges in the Andes Mountains of Peru. A robust assessment of modern glacier change is important for understanding how regional change affects Andean communities, and for placing paleo-glaciers in a context relative to modern glaciation and climate. Snowline altitudes (SLAs derived from satellite imagery are used as a proxy for modern (1986–2005 local climate change in a key transition zone in the Andes. Clear sky, dry season Landsat Thematic Mapper (TM and Enhanced Thematic Mapper (ETM+ satellite images from 1986–2005 were used to identify snowline positions, and their altitude ranges were extracted from an Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER digital elevation model (DEM. Based on satellite records from 31 glaciers, average snowline altitudes (SLAs, an approximation for the equilibrium line altitude (ELA, for the Cordillera Huayhuash (13 glaciers and Cordillera Raura (18 glaciers from 1986–2005 were 5051 m a.s.l. from 1986–2005 and 5006 m a.s.l. from 1986–2002, respectively. During the same time period, the Cordillera Huayhuash SLA experienced no significant change while the Cordillera Raura SLA rose significantly from 4947 m a.s.l. to 5044 m a.s.l.

  6. Uplift of the Eastern Cordillera, Colombia

    Science.gov (United States)

    Siravo, Gaia; Faccenna, Claudio; Giuditta Fellin, Maria; Molin, Paola; Bayona, German; Giachetta, Emanuele

    2017-04-01

    The Eastern Cordillera (EC) of Colombia is a double-vergent thrust and fold belt formed during the Cenozoic by the inversion of a Mesozoic rift. It is located 400 km far from the trench where the Nazca slab subducts below the South American plate. Tomography and seismicity highlight the presence of a flat slab subduction north of 5° N. Our goal is to explore the relation between surface and crustal processes in the topography growth of the EC north of 6° N. To reach this aim we integrate data derived from the fluvial network analysis with long-term erosion data derived from thermochronology. The northern EC is an asymmetric chain with a gentle flank on the western side and steep flank to the east. The two sides are separated by the maximum elevation of 5000 m reached at the Cocuy Sierra. Here the EC has the widest width ( 200 km) and changes northward to the Santander Massif Range. We obtained new low-T (U-Th)/He ages on zircons (ZHe) and apatites (AHe) from samples collected along two transects. Our ages combined with previous data indicate that along both transects exhumation occurred from shallow burial depths (≤ 6-8 km) during the Oligo-Miocene and locally continued until the Pliocene. Along the transect across the central part of the EC up to the Cocuy Sierra, the youngest Pliocene ages (AHe) are located at the highest elevations above 4000 m. Along the second transect the youngest ages are found close to and east of a main strike-slip structure (Bucaramanga fault). This fault has a significant dip-slip component evidenced by an offset of about 10 Ma among the AHe ages across the fault. The main rivers draining the northern EC flow parallel to the main tectonic structures and locally cut across them. The analysis of river longitudinal profiles reveal transient features such as knickpoint not related to lithological or structural contrast. Channel slope and chi analysis suggest a river capture event possibly influenced by the crustal structures. Wind gaps

  7. CONTENEDORES Y CONTENIDOS. EXPLORANDO EL CONSUMO DE VEGETALES DURANTE EL PERÍODO TARDÍO (ANTOFAGASTA DE LA SIERRA, PROVINCIA DE CATAMARCA / Containers and contents. Exploring the vegetable consumption during the Late Period (Antofagasta de la Sierra, Pro

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    Leticia Inés Gasparotti

    2015-12-01

    Full Text Available En este trabajo se presentan los resultados obtenidos de la integración de diversas líneas de evidencia vinculadas al estudio de un recipiente cerámico recuperado en el sitio Corral Alto (Antofagasta de la Sierra, Prov. de Catamarca. Se analizan las características morfo-tecnológicas de este recipiente, en relación a su uso, para indagar en las prácticas cotidianas relacionadas con la obtención, consumo, procesamiento o almacenamiento de recursos vegetales. Al mismo tiempo, a través del análisis múltiple de microfósiles (fitolitos y almidones entre otras evidencias, se intenta una aproximación al uso y/o consumo de recursos vegetales silvestres y domesticados por parte de grupos agro-pastoriles durante el período Tardío (ca. 1000- 500 AP en la Puna Meridional. AbstractIn this paper we present the results of the integration of various lines of evidence related to the study of a ceramic container recovered at the site of Corral Alto (Antofagasta de la Sierra, Prov. Catamarca. We analyze morpho- technological characteristics of the vessel related to their use to enquire into the daily practices related to the collection, use, processing or storage of vegetal resources. At the same time, we conducted a multiple microfossil analysis (phytoliths and starches among other evidences to identify the use and /or consumption of wild and domesticated plant resources by agro-pastoralist groups during the Late Period (ca. 1000- 500 BP in the Southern Puna.

  8. Early Cretaceous continental sedimentation in the Coastal Cordillera (Atajaña Formation), Northern Chile

    Science.gov (United States)

    Fuentes, G.; Garcia, M.; Sepulveda, F.; Vasquez, P.

    2013-12-01

    Early Cretaceous continental sedimentation development at the Coastal Cordillera of northern Chile has been described in a broad sense. The Atajaña Formation represents this continental sedimentation, south of Arica (18°30S), where it exposes mostly as an elongated swath oriented N70°E, forming a 20 km long and 8 km wide area of outcrop. Northward, these deposits occur as isolated outcrops at the bottom of Chiza, Camarones, Vitor and Azapa valleys. The Atajaña succession was deposited in apparent angular unconformity over Cuya Formation (Middle-Late Jurassic) and Chiza Formation (Bajocian-Oxfordian). The Atajaña Formation is overlain, conformable and transitional, by the Blanco Formation (Aptian-Albian) and overlain in erosion unconformity by the Suca Formation (upper Early Cretaceous). Angular unconformity contact between Atajaña Formation and Cenozoic units (Azapa Formation and alluvial deposits) is exposed at previously named valleys. In the Camarones valley, the Atajaña Formation unconformably overlies Middle to Late Jurassic intrusive rocks. In this work, the Atajaña Formation is divided in three facies associations, exposed close to Atajaña hill and Chiza valley (Kia1, Kia2 y Kia2a). Reddish conglomerates and sedimentary breccias facies (Kia1) consists of an up to 850 m thick. These rocks are massive, polymictic and poorly-sorted, and form laterally extensive beds. Clasts are mostly composed by diorites, monzodiorites, grayish fine sandstones, fine calcareous sandstones, limestones, volcarenites and porphyric andesites. Facies Kia1 includes interbedded red calcareous sandstones and siltstones, some of them displaying low-angle cross bedding. Facies Kia2 consists of an up to 570 m thick of red sandstone and siltstone, interbedded with conglomerates. This well stratified succession, parallel bedded and minor cross bedded, form continuous beds with subrounded and well-sorted clasts. Previous authors described dessication cracks in the red siltstones

  9. Lower-crustal flow and detachment in the North American Cordillera: a consequence of Cordillera-wide high temperatures

    Science.gov (United States)

    Hyndman, R. D.

    2017-06-01

    In this paper, I make the case for widespread lower-crustal detachment and flow in the North American Cordillera. An indicator that geologically recent flow has occurred comes from seismic structure data showing the crust in most of the Cordillera from Mexico to Alaska is uniformly thin, 33 ± 3 km, with a remarkably flat Moho. The flat Moho is in spite of extensive normal faulting and shortening that might be expected to deform the Moho. It has been concluded previously that the high topographic elevations are due to thermal expansion from Cordillera-wide high temperatures compared to stable areas, not due to a crustal root. I argue that the constant crustal thickness and flat Moho also are a consequence of temperatures sufficiently hot for flow in the lower crust. Lower-crust detachment and flow has previously been inferred for Tibet and the high Andes where the crust is thick such that unusually high temperatures are expected. More surprising is the similar conclusion for the Basin and Range of western USA where the crust is thin, but high temperatures have been inferred to result from current extension. There are now adequate data to conclude the Basin and Range is not unique in crustal thickness or in temperature. The crust in most of the Cordillera is similarly hot in common with many other backarcs. Five thermal constraints are discussed that indicate that for most of the Cordillera, the temperature at the Moho is 800-850 °C compared to 400-450 °C in stable areas. At these temperatures, the effective viscosity is low enough for flow near the base of the crust. The backarc Moho may be viewed as a boundary between almost 'liquid' lower crust over a higher viscosity, but still weak upper mantle. The temperatures are sufficiently high for the Moho to relax to a nearly horizontal gravitational equipotential over a few tens of millions of years. The inference of a weak lower crust also suggests that topography over horizontal scales of over 100 km must be short

  10. PRIMEROS AVANCES EN LA CARACTERIZACIÓN GEOQUÍMICA DE VULCANITAS DE AFLORAMIENTOS DE ANTOFAGASTA DE LA SIERRA (PROV. DE CATAMARCA, ARGENTINA / First advances in the geochemical characteristics of volcanic outcrops of Antofagasta de la Sierra (Catamarca

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    Alejandra M. Elías

    2013-07-01

    Full Text Available En distintos sectores de la microrregión de Antofagasta de la Sierra (Provincia de Catamarca, Puna Meridional Argentina se registran afloramientos de vulcanitas (rocas volcánicas con proporciones de vidrio menores a 80%, sensu Aschero et al. 2002/2004 macroscópicamente muy similares. Con el objetivo de diferenciarlas y aportar, de esta forma, a su identificación en el registro arqueológico, se aplicaron diversos métodos y técnicas sobre muestras de estas rocas procedentes de los distintos afloramientos. En esta instancia, se exponen los resultados obtenidos a partir de caracterización geoquímica por medio de Fluorescencia de Rayos X de Energía Dispersiva. Las vulcanitas procedentes de los diferentes afloramientos tienden a presentar disímiles concentraciones de ciertos elementos. Estos resultados son prometedores y estimulan a continuar investigando la aplicación de métodos geoquímicos en la diferenciación y determinación de la procedencia de estas rocas volcánicas. Cabe destacar que en el Noroeste Argentino los métodos geoquímicos fueron exclusivamente aplicados sobre una roca volcánica específica, la obsidiana, y aún no habían sido utilizados en otras rocas volcánicas anisótropas, con superficies, texturas y estructuras más irregulares. Abstract   In different sectors of the Antofagasta de la Sierra micro-region (Catamarca Province, Southern Argentine Pune outcrops of macroscopically very similar vulcanites (volcanic rocks with ratios of glass below 80%, sensu Aschero et al. 2002/2004 have been recorded. In order to differentiate between these and contribute to their identification in the archaeological record, various methods and techniques were applied to samples of these rocks. In this instance, the initial results obtained from geochemical characterization, through Energy Dispersive X-ray Fluorescence, are presented. The vulcanites from different outcrops tend to show different concentrations for some elements

  11. A Cool Urban Island Change 1990 - 2014. Comparative Bioclimatic Analysis in a Desert Climate, the Case of Antofagasta City Square

    Science.gov (United States)

    Pérez Lancellotti, Gino; Ziede Bize, Marcela

    2017-10-01

    This article proposes to make a comparative bioclimatic analysis from 1990 to 2014 of the main square of Antofagasta, a coastal desert city in Chile, which was remodelled in 1995, and shows how the redesigning of green areas affects the microclimatic conditions and thermal comfort of the urban space. Ex ante measurements dating 1990 were compared with ex post results from 2014. Data were obtained in both cases in the month of September at different times of a day and in different climate conditions. The variables studied were: land surface temperature, humidity, wind speed, amount of light and square use frequency inside the square and in surrounding streets. The temperatures are not statistically different during the years 1990 and 2014 for the city of Antofagasta. The main layout of the square has not changed, and inside the square it is similar for both periods, but new species were introduced and bigger trees with shadow projection were cut down. The square had a micro-climate role in 2014 as well as in 1990. The highest frequency zone with an important surface lost it is comfort thermic condition with an increase of 1°C. Other smaller zones with less relevance for users gained in cooling with a 0.5°C reduction. The new design has been detrimental to the intensity of its micro climatic regulatory function affecting the thermic comfort of the square’s internal spaces, especially those formerly protected by shadow, which mitigate a high solar radiation. The study results suggest that bio-climatic analysis of public open spaces is a key component for the design of future projects as a heat mitigating tool in the context of climate change. Research question is: How does the redesign of the square impact a cool urban island and the thermic comfort of users? Significant differences between data in situ collected in 1990 and 2014. Thermal comfort was negatively affected by the redesign in the square. The square is still a cool island but with less strength.

  12. S.A.G.A.R.A.: 'sistema de ayuda a la gestión del agua en la región de Antofagasta'

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    1998-01-01

    Full Text Available SAGARA : SYSTEME D’AIDE A LA GESTION DE L’EAU DANS LA REGION D’ANTOFAGASTA. La complexité de l’information collectée dans le domaine des ressources hydriques de la région d’Antofagasta a conduit à la mise en place d’un Système d’Information Géographique. Ce système géré par un puissant logiciel, fournit à tous ceux qui se préoccupent de la gestion de l’eau dans cette zone particulièrement aride, et aux besoins toujours croissants, une base de données très complète et à la fois très facile à utiliser. Ce SIG a pour but d’offrir un appui technique et ainsi permettre la gestion rationnelle d’un capital en eau limité. La complejidad de la información colectada a propósito de los recursos hídricos en la región de Antofagasta condujo a la elaboración de un Sistema de Información Geográfica. Este sistema, trabajado en un potente software, proporciona a quienes se preocupan de la gestión del agua en esta zona extremadamente árida, y con demandas en constante aumento, una base de datos muy completa y a la vez muy fácil de manejar. Este SIG pretende apoyar técnicamente una gestión racional del magro capital “agua”. SAGARA: MANAGEMENT WATER SUPPORT SYSTEM IN THE ANTOFAGASTA DISTRICT. The complexity of the information collected in the area of the hidrical resources in the Antofagasta district led to the settlement of a Geographical Information System. This highly powerful software managed system provides a very complete and easy-to-use database to who involved with all water management matters in such arid and constantly increasing requirements zone. GIS is aimed at providing a technical support so as to allow a more rational management of the scarce water capital.

  13. Fluid geochemistry of hydrothermal systems in the Arica-Parinacota, Tarapacá and Antofagasta regions (northern Chile)

    Science.gov (United States)

    Tassi, F.; Aguilera, F.; Darrah, T.; Vaselli, O.; Capaccioni, B.; Poreda, R. J.; Delgado Huertas, A.

    2010-04-01

    We investigate the chemical and isotopic composition of water and gas thermal discharges from six hydrothermal systems in the Tarapacà and Antofagasta regions (northern Chile): Surire, Puchuldiza-Tuja, Pampa Lirima, Pampa Apacheta, El Tatio and Torta de Tocorpuri, to determine the chemical-physical conditions at the fluid source. The chemical facies of the thermal discharges vary from Na +-Cl - (El Tatio, Puchuldiza-Tuja and part of Surire where SO 42--rich waters also occur) to Na +(Ca 2+)-Cl -(SO 42-) (Pampa Lirima), Ca 2+-SO 42-(HCO 3-) (Torta de Tocorpuri) and Ca 2+-SO 42- (Pampa Apacheta). The gas seeps are characterized by the dominance of CO 2, H 2S and CH 4 with N 2/Ar ratios that occasionally are up to 450. Significant amounts of SO 2 and HCl are present at Pampa Apacheta. Water and gas geothermometry suggests that El Tatio and Puchuldiza-Tuja fluid reservoirs have relatively high reservoir equilibrium temperature (up to 270 °C). Gases from Pampa Apacheta apparently equilibrated at unusually high temperature for hydrothermal fluids (up to 350 °C), being likely related to an active magmatic system, as testified by the presence of highly acidic gas compounds such as SO 2 and HCl. On the contrary, low equilibrium temperatures were calculated for the Surire fluids (El Tatio, Pampa Apacheta, Surire and Puchuldiza-Tuja can be regarded as the most promising areas and deserve more detailed geological investigations.

  14. Palynostratigraphy of the Zorritas Formation, Antofagasta region, Chile: Insights on the Devonian/Carboniferous boundary in western Gondwana

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    Claudia V. Rubinstein

    2017-05-01

    Full Text Available The Middle Member of the Zorritas Formation in the Antofagasta region of northern Chile, yielded terrestrial and marine palynomorph assemblages which span the Devonian/Carboniferous boundary. The assemblages show a clear predominance of terrestrial palynomorphs with 70 miospore species, 18 marine phytoplankton species, two non-marine algae and one chitinozoan species, all coming from 15 productive levels. Palynomorphs are poorly preserved and most of them are reworked. Three palynological associations are recognized based on miospores. These are assigned to the Tournaisian–Visean, Tournaisian and probable latest Famennian. Age assignments are discussed in the frame of the spore zonal schemes established for Euramerica and western Gondwana. The stratigraphical distribution of spores allows the identification of the probable position of the Devonian/Carboniferous boundary within the Zorritas Formation. This system boundary is proposed for the first time in Palaeozoic sedimentary rocks of northern Chile. The presence of Gondwanan typical miospore species indicates affinities with this palaeocontinent even though the Tournaisian and Tournaisian–Visean miospore associations support the cosmopolitanism already suggested for the early Carboniferous flora. The significant number of reworked palynomorphs together with the sedimentological analysis of the studied sections, suggest that these deposits were severely impacted by the climatic change and major sea level fluctuations. Similar conditions were recorded in coeval western Gondwana basins.

  15. Viajes comerciales de intercambio en el departamento de Antofagasta de la Sierra, Puna meridional argentina: pasado y presente.

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    García, Silvia P.

    2002-05-01

    Full Text Available Los viajes hacia valles interserranos a lomo de mula fueron una experiencia compartida por todos en esta región de la puna argentina, hasta hace veinte años. En este trabajo se relacionan los datos obtenidos a través de entrevistas a informantes en el departamento de Antofagasta de la Sierra, con los surgidos tras la consulta de las Actas del Registro Civil y se arriba a conclusiones respecto de los vínculos de parentesco que unieron a quienes comerciaban e intercambiaban mercaderías producidas en alturas diferentes. También se compara la situación de entonces con la actualidad. En la capital del departamento los viajes de intercambio han desaparecido casi en su totalidad, en cambio en otras poblaciones del mismo departamento se han modificado incluyendo en ellos a las mercaderías obtenidas por compra y utilizando la sal como principal elemento de canje.

  16. Climatic forcing of asymmetric orogenic evolution in the Eastern Cordillera of Colombia

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    Mora, A.; Parra, M.; Strecker, M.R.; Sobel, R.A.; Hooghiemstra, H.; Torres, V.; Vallejo Jaramillo, J.

    2008-01-01

    New apatite fission-track data, paleoelevation estimates from paleobotany, and recently acquired geological data from the Eastern Cordillera of Colombia document the onset of increased exhumation rates in the northeastern Andes at ca. 3 Ma. The Eastern Cordillera forms an efficient orographic

  17. Deformation monitoring in Zafarraya fault and Sierra Tejeda antiform (Betic cordillera, Spain) using satellite radar interferometry

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    Ruiz-Armenteros, A.M.; Delgado, J.M.; Sousa, J.J.; Hanssen, R.F.; Caro, M.; Gil, A.J.; Galindo-Zaldívar, J.; Galdeano, C.S. de

    2015-01-01

    The Betic-Rif cordilleras are build-up in the western Mediterranean by the deformations related to the Eurasian-African plate boundary. The recent NW-SE convergence produces the simultaneous development of large folds and faults in the central part of the Internal Zones of the Betic Cordilleras,

  18. Una nueva especie de Eleutherodactylus (Amphibia: Leptodactylidae de la Cordillera Central de Colombia Una nueva especie de Eleutherodactylus (Amphibia: Leptodactylidae de la Cordillera Central de Colombia

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    Roa Trujillo Sonia H.

    1991-06-01

    Full Text Available A new species of Eleutherodactylus, unistrigatus Group from the Cordillera Central in central Colombia is named. Additional characters of cranial morphology for defining the unistrigatus Group are given. Se nomina y describe una nueva especie de Eleutherodactylus del Grupo unistrigatus de la región central de la Cordillera Central de Colombia. Se presenta una descripción detallada de los caracteres craneales como un aporte para la definición de este Grupo.

  19. Parámetros reproductivos y poblacionales de Thais chocolata (Duelos, 1832 (Gastropoda, Thaididae, en la reserva marina La Rinconada, Antofagasta, Chile Reproductive and population parameters of Thais chocolata (Duclos, 1832 (Gastropoda, Thaididae in La Rinconada marine reserve, Antofagasta, Chile

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    Marcela Cantillánez

    2011-11-01

    Full Text Available Para obtener antecedentes reproductivos y poblacionales de Thais chocolata que contribuyan a validar su actual normativa pesquera, se realizó un estudio en el área protegida de la reserva marina La Rinconada, Antofagasta, Chile, entre diciembre 2008 y enero 2010. Los resultados obtenidos indicaron a nivel reproductivo, que el desarrollo gonadal de la población es asincrónico, encontrándose ejemplares en diferentes etapas de maduración durante el año. Los individuos maduros se estratificaron entre 5 y 13 m de profundidad, y gran parte del año formaron agregaciones a 5 m de profundidad. Se determinaron períodos de mayor madurez en julio-agosto, y en noviembre-enero, manifestándose las agregaciones más importantes al final de ellos. Una relación se observó entre meses de mayor madurez y registro de agregaciones, con aquellos de mayor variación intradiaria de temperatura. A nivel poblacional los resultados permitieron estimar una población de 2,3*10(6 ejemplares, donde el 39% se encontró sobre la talla mínima legal (TML = 55 mm. Los parámetros de crecimiento mostraron crecimiento relativamente lento, que podría estar influenciado por la alta variabilidad que presenta la temperatura de fondo en este sector. Mientras que su talla crítica, y la talla de primera madurez sexual poblacional, resultaron ser mayores a la TML. Se determinó la necesidad de revisar la normativa pesquera actual de esta especie, y se demostró la efectividad de las reservas marinas propiciadas por el Estado en la conservación de los recursos marinos.Reproductive and population parameters of Thais chocolata that would contribute to the validation of the current extraction standards were obtained by performing a study in the protected area of La Rinconada Marine Reserve, Antofagasta, Chile, from December 2008 to January 2010. In terms of reproduction, the results revealed asynchronic gonad development in the population, with specimens in different stages of

  20. Caracterización de estudiantes desde sus potencialidades y Talentos Académicos en la región de Antofagasta, Chile / Students Characterization from their Potential and Academic Talent in Antofagasta, Chile

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    Maria Caridad García Cepero

    2012-12-01

    Full Text Available La coyuntura actual de políticas educativas de cobertura, calidad, equidad y diversidad imponen desafíos a los establecimientos educacionales, especialmente a los municipales, los cuales deben desarrollar estrategias orientadas a satisfacer las necesidades de los estudiantes que se encuentran en sus aulas, capitalizando sus fortalezas. Esta investigación es de naturaleza exploratoria con una metodología mixta explicativa. Se presentan los resultados de la primera fase del estudio que corresponde al análisis de proyectos educativos y a la caracterización de estudiantes sobresalientes. Se analizaron los resultados obtenidos de 1.536 estudiantes provenientes de 18 establecimientos educacionales de las comunas de Antofagasta y Calama (Chile. A partir del análisis y de acuerdo a indicadores de talento académico, la muestra fue caracterizada en cuatro grupos de estudiantes: estudiantes sobresalientes, sub-nominados, sobre-exigidos y promedio. La categoría de estudiantes subnominados plantea cuestionamientos referentes a la metodología de identificación de estudiantes con talento en los programas chilenos, fuertemente cimentada en la nominación docente. Se advierte la necesidad de generarrutas alternativas, como la autonominación. Para concluir, se hacen algunas sugerencias alrededor de las políticas públicas en relación con la educación para estudiantes sobresalientes en particular para Chile, pero pueden ser en buena medida transferidas a otros casos a través de Iberoamérica.

  1. Variación fenotípica y genética en el tunicado Pyura praeputialis (Heller, 1878 en el área norte de la Bahía de Antofagasta, Chile Phenotypic and genetic variation in tunicate Pyura praeputialis (Heller, 1878 in the northern sac of the Antofagasta Bay

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    MARCELA ASTORGA

    2002-09-01

    Full Text Available La morfología de los "piures" (Urochordata: Tunicata es altamente variable, mostrando diferencias hábitat-específicas con una base intra- o interespecífica, lo cual dificulta la comprensión de sus significados taxonómicos, ecológicos y evolutivos. En el presente trabajo se caracterizó genéticamente, mediante polimorfismos de isoenzimas, a tres morfotipos de piures: achatados, intermedios y alargados, observados en poblaciones intermareales del "piure de Antofagasta" Pyura praeputialis. El estudio se realizó en tres localidades que se distribuyen en un gradiente de exposición al oleaje en el extremo norte de la Bahía de Antofagasta, Chile. Se analizó un total de 17 loci isoenzimáticos, a través de electroforesis en gel de almidón, de los cuales tres fueron polimórficos: IDH-1, MDH-1 y PGM-1. Los resultados sugieren diferencias morfológicas pero no genéticas entre los morfotipos. Sin embargo, las localidades difieren significativamente en su estructura genética. Se compara los resultados en relación a las respuestas observadas para morfotipos semejantes en Australia, sobre la base de que P. praeputialis habría colonizado recientemente la Bahía de Antofagasta. Se concluye que las diferencias entre los morfotipos en Antofagasta tienen una base intraespecífica y en Australia interespecífica y se discute las hipótesis que podrían explicar las diferencias genéticas y fenotípicas observadasThe morphology of "sea squirts" (Urochordata: Tunicata is highly variable and is expressed in habitat-specific differences intra- and interspecific variation pattern that had hindered the interpretation of such differences as well as their taxonomical, ecological or evolutionary meaning. Here we describe the population genetic structure of three morphotypes (squat, intermediate and tall "sea squirt" observed in populations of the "piure de Antofagasta", Pyura praeputialis by enzyme electrophoresis. The study was carried out in three

  2. Diagnóstico socio-ambiental para un desarrollo sustentable de la Puna Meridional Argentina, Localidad de Antofagasta de la Sierra, Catamarca

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    Liliana M. Manzi

    2008-05-01

    Full Text Available Se presenta un diagnóstico socio-ambiental realizado en la comunidad de Antofagasta de la Sierra, Provincia de Catamarca, Argentina, siendo tomados en consideración las unidades sociales de producción, los rebaños, las pasturas disponibles y los patrones de uso y tenencia de la tierra. Se pretende identificar y evaluar la incidencia del actual uso del espacio sobre el medio natural y discutir las iniciativas oficiales de desarrollo económico para este sector de la Puna argentina.

  3. Slab flattening, dynamic topography and normal faulting in the Cordillera Blanca region (northern Peru)

    Science.gov (United States)

    Margirier, A.; Robert, X.; Laurence, A.; Gautheron, C.; Bernet, M.; Simon-Labric, T.; Hall, S. R.

    2015-12-01

    Processes driving surface uplift in the Andes are still debated and the role of subduction processes as slab flattening on surface uplift and relief building in the Andes is not well understood. Some of the highest Andean summits, the Cordillera Blanca (6768 m) and the Cordillera Negra (5187 m), are located above a present flat subduction zone (3-15°S), in northern Peru. In this area, both the geometry and timing of the flattening of the slab are well constrained (Gutscher et al., 1999; Rosenbaum et al., 2005). This region is thus a perfect target to explore the effect of slab flattening on the Andean topography and uplift. We obtained new apatite (U-Th)/He and fission-track ages from three vertical profiles located in the Cordillera Blanca and the Cordillera Negra. Time-temperature paths obtained from inverse modeling of the thermochronological data indicates a Middle Miocene cooling for both Cordillera Negra profiles. We interpret it as regional exhumation in the Cordillera Occidental starting in Middle Miocene, synchronous with the onset of the subduction of the Nazca ridge (Rosenbaum et al., 2005). We propose that the Nazca ridge subduction at 15 Ma and onset of slab flattening in northern Peru drove regional positive dynamic topography and thus enhanced exhumation in the Cordillera Occidental. This study provides new evidence of the impact subduction processes and associated dynamic topography on paleogeography and surface uplift in the Andes.

  4. A new climate and glacier baseline for the Cordillera Vilcanota, Peru, reduces critical information gaps

    Science.gov (United States)

    Salzmann, Nadine; Huggel, Christian; Rohrer, Mario; Silverio, Walter; Mark, Bryan G.; Cochachin, Alejo; Suarez, Wilson; Giráldez, Claudia

    2013-04-01

    The Cordillera Vilcanota in the Southern Peruvian Andes is the second largest ice-covered Cordillera in Peru (after the Cordillera Blanca) and serves for the Cusco Region as a temporary water storage for fresh-water and hydropower generation and irrigation. Despite the Cordillera Vilcanota's size and socio-economic relevance, there has so far no comprehensive baseline data been available for climate and glacier evolution. In the framework of two jointly launched -Peruvian-Swiss climate change impact and adaptation programs (Climate Change Adaptation Programm - PACC; Glacier Change Adaptation and Desaster Risk Reduction Programm - Glacier 513) significant efforts have been undertaken and are on the way to create a climate, glacier and hazard baseline for the Cordillera Vilcanota. Because of the remoteness of the area and the scarcity of available data, multiple sources such as climate stations, climate reanalysis and satellite data have been collected, processed and analyzed. Based on our data, we found only marginal glacier changes between 1962 and 1985, but a massive ice loss since 1985 (about 30% of area and about 45% of volume). These high numbers corroborate studies from other glacierized cordilleras in Peru. The climate data show overall a moderate increase in air temperature, and mostly weak and not significant trends for precipitation sums, which probably cannot fully explain the observed substantial ice loss. The likely increase of specific humidity in the upper troposphere, where the glaciers are located, probably played a major role in the observed massive of the Cordillera Vilcanota over the past decades. The mass balance measurements initiated in 2010 on two glaciers of the Cordillera Vilcanota, and the climate station installed in 2011 on one of the glaciers, preliminarily indicate that ice loss (in water equivalent) is clearly lower that in the Cordillera Blanca. In the near future the data will provide new and important insights on climate and

  5. Sexualidad y autocuidado en jóvenes de la ciudad de Antofagasta en un contexto de transformaciones culturales

    Directory of Open Access Journals (Sweden)

    Beatriz Cofré Espinoza

    2014-09-01

    Full Text Available En este artículo se exponen los resultados obtenidos del análisis interpretativo hermenéutico de 27 entrevistas semiestructuradas sobre sexualidad realizadas a jóvenes estudiantes secundarios, 12 mujeres y 15 hombres, de entre 15 y 17 años de edad, de la ciudad de Antofagasta, una ciudad minera ubicada en el norte de Chile. El análisis se centró en la construcción de su sexualidad y su posición frente a las normas vigentes, en un contexto sociocultural local vinculado a la actividad minera y un contexto general de transformaciones culturales en Chile. Dos puntos importantes emergen desde los análisis. En primer lugar, que las familias de los jóvenes participantes de este estudio transmiten ideologías de género predominantemente tradicionales y que persisten en modelos de crianza restrictivos respecto de la sexualidad, especialmente en las mujeres. En consecuencia, para ambos, hombres y mujeres, su sexualidad está determinada por el temor al embarazo, enfermedades de transmisión sexual, y la posibilidad de ser descubiertos teniendo relaciones sexuales. Así, el miedo se convierte en un factor central en la organización del comportamiento sexual, dificultando la experiencia de una sexualidad placentera y centrada en el autocuidado. En segundo lugar, los discursos de los jóvenes también dan cuenta de familias en las que se ha ido produciendo una flexibilización de los roles de género y una tendencia a la homogeneización de los proyectos de vida de hombres y mujeres jóvenes. Así, la planificación tardía de la maternidad, la preparación y valoración del trabajo remunerado en las mujeres y el reconocimiento de la legitimidad del deseo sexual femenino son elementos que orientan sus decisiones sobre sexualidad favoreciendo la prevención y el autocuidado. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs1403175

  6. New glaciological research projects in the Cordillera Vilcanota - Cusco - Peru

    Science.gov (United States)

    Montoya, Nilton; Molina, Edwin; Schauwecker, Simone; Haeberli, Wilfried; Giraldez, Claudia; Drenkhan, Fabian; Huggel, Christian

    2015-04-01

    Tropical glaciers are highly sensitive to alterations in climate and therefore good indicators for global climate change. Glaciers located in Peru represent 71% of all tropical glaciers in the world, and have shown a significant area reduction of about 43% within the last 40 years mainly due to the increase in surface temperature. Tropical glaciers play a particular role as freshwater reservoirs and buffers to river discharge variability and water scarcity within a pronounced wet and dry season. Their monitoring is extraordinarily important but few studies exist on mass balance. The Cordillera Vilcanota, at the origin of the Rio Vilcanota-Urubamba, contains about 25% of all glaciers in Peru. In recent decades, glacier shrinkage has accelerated in this mountain range. Between 1988 and 2010, glacier area was reduced at an annual rate of about 4 km2 (1.1 %) from some 360 km2 to about 270 km2 (25%). A total volume loss of 40-45% (from 17-20 km3 to 9.2-12.4 km3) can be estimated for the period 1962-2006, with an accelerated rate since the 1980s. In 2010/11, first point net mass balance measurements were carried out on Suyuparina glacier and the adjacent Quisoquipina glacier. In 2013, mass balance measurements were reinitiated in the frame of a long-term monitoring campaign. The first year of direct mass balance measurements (stakes and pits) show that ablation is highly influenced by the complex microtopography of the glacier, mainly characterized by the existence of ice cliffs, causing a spatially heterogeneous ablation pattern. There is a large scatter in point mass balance in function of elevation, which makes it difficult to estimate accurately the equilibrium line altitude (ELA) and the annual total glacier mass balance from these point measurements. For the hydrological year 2013/14, stake measurements for sites on the lower part of the glacier varied between +0.2 and -4 m w.e. (water equivalent), while accumulation in the uppermost part of the glacier showed

  7. Relative Quantification of Costal Cordillera (Ecuador) Uplift : Preliminary Results from Quantitative Geomorphology

    Science.gov (United States)

    Reyes, Pedro; Dauteuil, Olivier; Michaud, François

    2010-05-01

    The coastal cordillera of Ecuador (culminating point around 800 m) includes on its littoral margins uplifted marine terraces (maximum known 360 m). The coastal cordillera constitutes an important barrier of drainage and on nearly 600 km the drainage resulting from the Andes is diverted towards Río Guayas in the South and Río Esmeraldas in North. What is the uplifting mode of the coastal cordillera? For how long it has constituted a barrier of drainage? Does the coastal cordillera rising be linked with the littoral margin rising? Does the cordillera have raised in a homogeneous or segmented way? What is the geodynamic process of the uplift of the cordillera? Can this uplift be related with the subduction of the Carnegie ridge? The first objective of this work is to analyze the morphology of the coastal cordillera with helps of quantitative geomorphology using digital techniques such as DEM (realized with a resolution of 30 m by Marc Souris, IRD), to specify the evolution of the coastal cordillera uplift. This study was carried out starting combining analysis of morphology, maps derived from the slopes and anomalies of the drainage of the hydrographic network. In the second time, three methods were applied to DEM data using the ArcGIS software: 1) the digitalization and the interpolation of basal surface of the last marine formation of regional distribution (the Borbón formation on the geological map of Ecuador) to determine paleo-horizontal and to see its deformation; 2) the extraction of 109 profiles of rivers which allow us to calculate for each river the vertical, horizontal, and total deviation compared to the theoretical profile of the river and the associated SL index; 3) the measurement of the relief incision (depth + half width of the valley, on the whole 7500 measurements) according to the method of Bonnet et al. (1998). We adapted this method to be able to represent the state of incision in any point, correcting from the influence of the lithology and

  8. Crecimiento y estructura demográfica de Argopecten purpuratus en la Reserva Marina La Rinconada, Antofagasta, Chile

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available Se presentan los parámetros de crecimiento L∞ = 120.38 mm y K = 0.9668 para el banco de Argopecten purpuratus de la Reserva Marina La Rinconada (Antofagasta, Chile, obtenidos entre marzo de 2001 y mayo de 2003 usando métodos de marcaje y recaptura de ejemplares. La elevada recaptura de individuos marcados (60–80% indica baja mortalidad natural y una conducta sedentaria del recurso. Las evaluaciones anuales realizadas para estimar el tamaño del banco confirmaron tal conducta, encontrándose la mayoría de los individuos agregados en el centro, con densidades que variaron entre años de 9 a 14.8 ind m–2. La abundancia de ejemplares también mostró variabilidad interanual, con cifras de 10.1 × 106 en 2001, 8.2 × 106 en 2002 y 12.4 × 106 en 2003. Estas evaluaciones mostraron, además, una disminución en la talla media de la estructura demográfica del banco entre un año y otro, reduciéndose de 75.8 mm en 2001 a 62.1 mm en 2002 y a 51.7 mm en 2003. Esta disminución también ocurrió con el número de ejemplares mayores o iguales a la talla mínima legal (90 mm, reduciéndose de 2.6 × 106 ejemplares presentes en 2001 a 3.7 × 105 ejemplares en 2003. La aplicación de los parámetros de crecimiento sobre la estructura poblacional del banco entre 2002 y 2003 señaló la integración de una nueva clase anual de 6.5 × 106 de ejemplares en 2002 y de 11.2 × 106 de individuos en 2003. El descuento de estas cifras, del número total de ejemplares presentes en ambos años, demuestra una pérdida cercana a los 8.4 × 106 de ostiones en 2002 y de cerca de 7.0 × 106 de individuos en 2003. Estas pérdidas correspondieron a ejemplares con tallas superiores a los 60 mm, lo cual es corroborado con el análisis de la curva de captura realizado con el programa Fisat, cuyos resultados señalan una mortalidad Z = 2.15 en 2002 para el segmento de la población entre 67.5 y 115.5 mm, y Z = 3.08 en 2003 para el segmento de 64.3 a 112.5 mm. Los

  9. Artificial collection and early growth of spat of the scallop Argopecten purpuratus (Lamarck, 1819, in La Rinconada Marine Reserve, Antofagasta, Chile

    Directory of Open Access Journals (Sweden)

    Miguel Avendaño D.

    2007-03-01

    Full Text Available Artificial collection of early juveniles (“spat” of the scallop Argopecten purpuratus in Japanese-type collectors was evaluated between January 2001 and July 2002 in the La Rinconada Marine Reserve, Antofagasta, Chile. This area of Antofagasta Bay has in the past been noted for the retention of scallop larvae by local gyres, in which their numbers can vary between 89 and 34175 larvae m-3, producing larval sets of 400 to 15340 post-larvae (spat per collector. The results showed no quantitative relationship between larval abundance in the water and the spat density collected per day in the collectors, although high settlement rates were associated with high numbers of umboned larvae in the water. Allowing collectors to remain in situ for extended periods of 88 and 159 days resulted in a severe loss of seed which had settled in the collectors during the first 28 to 40 days of immersion. These losses varied between 50.9 and 99.6% of the spat collected, and were more prejudicial for the smaller cohorts that had settled in the collectors at the end of the first immersion period. The growth rates measured among different cohorts for each immersion period varied between 81.3 and 235.2 mm/day for the first cohort (C1 and between 64.0 and 167.4 mm/day for the second cohort (C2. The highest growth rates occurred in collectors containing the lowest numbers of spat after the occurrence of spat losses during the long periods of immersion. Occurrence of intraspecific competition within the collectors is discussed as potentially responsible for the decreases in spat numbers and the variations observed in their growth rates.

  10. Active rollback in the Gibraltar Arc: Evidences from CGPS data in the western Betic Cordillera

    Science.gov (United States)

    Gonzalez-Castillo, L.; Galindo-Zaldivar, J.; de Lacy, M. C.; Borque, M. J.; Martinez-Moreno, F. J.; García-Armenteros, J. A.; Gil, A. J.

    2015-11-01

    The Gibraltar Arc, located in the western Mediterranean Sea, is an arcuate Alpine orogen formed by the Betic and Rif Cordilleras, separated by the Alboran Sea. New continuous GPS data (2008-2013) obtained in the Topo-Iberia stations of the western Betic Cordillera allow us to improve the present-day deformation pattern related to active tectonics in this collision area between the Eurasian and African plates. These data indicate a very consistent westward motion of the Betic Cordillera with respect to the relatively stable Iberian Massif foreland. The displacement in the Betics increases toward the south and west, reaching maximum values in the Gibraltar Strait area (4.27 mm/yr in Ceuta, CEU1, and 4.06 mm/yr in San Fernando, SFER), then progressively decreasing toward the northwestern mountain front. The recent geological structures and seismicity evidence moderate deformation in a roughly NW-SE to WNW-ESE compressional stress setting in the mountain frontal areas, and moderate extension toward the internal part of the cordillera. The mountain front undergoes progressive development of folds affecting at least up to Pliocene deposits, with similar recent geological and geodetical rates. This folded strip helps to accommodate the active deformation with scarce associated seismicity. The displacement pattern is in agreement with the present-day clockwise rotation of the tectonic units in the northern branch of the Gibraltar Arc. Our data support that the westward emplacement of the Betic Cordillera continues to be active in a rollback tectonic scenario.

  11. Late Pleistocene glacial fluctuations in Cordillera Oriental, subtropical Andes

    Science.gov (United States)

    Martini, Mateo A.; Kaplan, Michael R.; Strelin, Jorge A.; Astini, Ricardo A.; Schaefer, Joerg M.; Caffee, Marc W.; Schwartz, Roseanne

    2017-09-01

    The behavior of subtropical glaciers during Middle to Late Pleistocene global glacial maxima and abrupt climate change events, specifically in Earth's most arid low-latitude regions, remains an outstanding problem in paleoclimatology. The present-day climate of Cordillera Oriental, in arid northwestern Argentina, is influenced by shifts in subtropical climate systems, including the South American Summer Monsoon. To understand better past glacier-subtropical climates during the global Last Glacial Maximum (LGM, 26.5-19 ka) and other time periods, we combined geomorphic features with forty-two precise 10Be ages on moraine boulders and reconstructed paleo-equilibrium line altitudes (ELA) at Nevado de Chañi (24°S) in the arid subtropical Andes. We found a major glacial expansion at ∼23 ± 1.6 ka, that is, during the global LGM. Additional glacial expansions are observed before the global LGM (at ∼52-39 ka), and after, at 15 ± 0.5 and 12 ± 0.6 ka. The ∼15 ka glacial event was found on both sides of Chañi and the ∼12 ka event is only recorded on the east side. Reconstructed ELAs of the former glaciers exhibit a rise from east to west that resembles the present subtropical climate trajectory from the Atlantic side of the continent; hence, we infer that this climate pattern must have been present in the past. Based on comparison with other low-latitude paleoclimate records, such as those from lakes and caves, we infer that both temperature and precipitation influenced past glacial occurrence in this sector of the arid Andes. Our findings also imply that abrupt deglacial climate events associated with the North Atlantic, specifically curtailed meridional overturning circulation and regional cooling, may have had attendant impacts on low subtropical Southern Hemisphere latitudes, including the climate systems that affect glacial activity around Nevado de Chañi.

  12. Investigation of a measles outbreak in Cordillera, northern Philippines, 2013

    Directory of Open Access Journals (Sweden)

    Paola Katrina Ching

    2016-07-01

    Full Text Available Introduction: Measles is a highly infectious viral illness that remains one of the leading causes of death among children worldwide. In the Philippines, decreasing routine vaccination coverage from 2007 to 2011 led to local measles outbreaks. A team investigated a measles outbreak reported in Cordillera of the Philippines in May 2013. Methods: Measles case data with symptom onset from 2 February to 27 May 2013 were obtained from official sources and verified on site. Data included age, sex, residential address, signs and symptoms and vaccination status. Active case-findings were also conducted for contacts of these cases. The living environments of the cases were investigated. A survey was conducted with the cases and caregivers to understand their knowledge and attitudes about measles. Results: There were 50 measles cases identified with an age range from six months to 32 years (median: 16 years. Thirty-two were male (64%. Twenty (40% were hospitalized with one death. Thirty-two (64% cases were laboratory confirmed, and 36 (72% received a single dose of measles vaccine. Overcrowded living environments were observed among many cases. The majority of respondents (46/48, 96% knew about measles, but there were misconceptions about the cause of measles and how it can be prevented and managed. Conclusion: This measles outbreak occurred in an area with low immunization coverage. Achieving 95% measles immunization coverage and strengthening routine immunization strategies to address high-risk populations are recommended. Also, we recommend health education campaigns to include components that address misconceptions about measles.

  13. Nueva especie de rana (Atelopus de Los Farallones de Cali, Cordillera Occidental de Colombia

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    Kattan Gustavo

    1986-06-01

    Full Text Available Durante la realización de colecciones herpetológicas en el Departamento del Valle del Cauca, fue encontrada una especie no descrita de Atelopus (Anura: Bufonidae en los farallones de Cali, a 2600 m de altura. Esta es la primera especie en este género que se encuentra a elevaciones superiores a 2000 m en la Cordillera Occidental. Se conocen varias especies de Atelopus en las Cordilleras Central y Oriental de Colombia y en los Andes ecuatorianos (COCHRAN y GOIN 1970; PETERS 1973; RIVERO 1963 y probablemente futuras colecciones herpetológicas continuaran revelando nuevas especies en las partes altas de la Cordillera Occidental.

  14. Mantle plume influence on the Neogene uplift and extension of the US western Cordillera?

    Science.gov (United States)

    Parsons, T.; Thompson, G.A.; Sleep, Norman H.

    1994-01-01

    Despite its highly extended and thinned crust, much of the western Cordillera in the United States is elevated more than 1km above sea level. Therefore, this region cannot be thought of as thick crust floating isostatically in a uniform mantle; rather, the lithospheric mantle and/or the upper asthenosphere must vary in thickness or density across the region. Utilizing crustal thickness and density constraints, the residual mass defcicit that must occur in the mantle lithosphere and asthenosphere beneath the western Cordillera was modelled. A major hot spot broke out during a complex series of Cenozoic tectonic events that included lithospheric thickening, back-arc extension, and transition from subduction to a transform plate boundary. It is suggested that many of the characteristics that make the western Cordillera unique among extensional provinces can be attributed to the mantle plume that created the Yellowstone hot spot. -Authors

  15. Glacier surface mass balance and freshwater runoff modeling for the entire Andes Cordillera

    Science.gov (United States)

    Mernild, Sebastian H.; Liston, Glen E.; Yde, Jacob C.

    2017-04-01

    Glacier surface mass balance (SMB) observations for the Andes Cordillera are limited and, therefore, estimates of the SMB contribution from South America to sea-level rise are highly uncertain. Here, we simulate meteorological, snow, glacier surface, and hydrological runoff conditions and trends for the Andes Cordillera (1979/80-2013/14), covering the tropical latitudes in the north down to the sub-polar latitudes in the far south, including the Northern Patagonia Ice Field (NPI) and Southern Patagonia Ice Field (SPI). SnowModel - a fully integrated energy balance, blowing-snow distribution, multi-layer snowpack, and runoff routing model - was used to simulate glacier SMBs for the Andes Cordillera. The Randolph Glacier Inventory and NASA Modern-Era Retrospective Analysis for Research and Applications products, downscaled in SnowModel, allowed us to conduct relatively high-resolution simulations. The simulated glacier SMBs were verified against independent directly-observed and satellite gravimetry and altimetry-derived SMB, indicating a good statistical agreement. For glaciers in the Andes Cordillera, the 35-year mean annual SMB was found to be -1.13 m water equivalent. For both NPI and SPI, the mean SMB was positive (where calving is the likely reason for explaining why geodetic estimates are negative). Further, the spatio-temporal freshwater river runoff patterns from individual basins, including their runoff magnitude and change, were simulated. For the Andes Cordillera rivers draining to the Pacific Ocean, 86% of the simulated runoff originated from rain, 12% from snowmelt, and 2% from ice melt, whereas, for example, for Chile, the water-source distribution was 69, 24, and 7%, respectively. Along the Andes Cordillera, the 35-year mean basin outlet-specific runoff (L s-1 km-2) showed a characteristic regional hourglass shape pattern with highest runoff in both Colombia and Ecuador and in Patagonia, and lowest runoff in the Atacama Desert area.

  16. Impact of the Canadian Shield-Cordillera tectonic transition on controlling deformation within western Canada

    Science.gov (United States)

    Schaeffer, A. J.; Audet, P.; Mallyon, D.; Chen, Y.; Currie, C. A.; Gu, Y. J.

    2016-12-01

    Assembly of North America has been ongoing for more than 2 Ga, though geologically recent activity has been largely confined to the western margin—the Cordillera. Unlike a typical plate boundary fault, the Cordillera is characterized by a broad zone of distributed deformation as much as 800 km in lateral extent. The Canadian Cordillera is observed to have elevated heat flow, high topography, and a thin and weak lithosphere. Juxtaposed immediately to the east acting as a rigid backstop to deformation, is the strong and thick Canadian Shield. Both the location and nature of the Cordillera-Craton transition have been a subject of much study and debate. Past results suggest that the Cordilleran Deformation Front may mark the western extent of the cratonic lithosphere, whereas others indicate it extends further west, up to the Tintina Fault-Rocky Mountain Trench system. In the Mackenzie and Richardson Mountains of the northern Canadian Cordillera, this boundary likely becomes more complex and elusive due to the arcuate nature of the predominant tectonic structures. Despite high levels of seismicity across much of the region, detailed study has been limited by insufficient coverage of seismological infrastructure. With the USArray Transportable Array now deployed in Alaska and northwestern Canada, combined with several active regional arrays (e.g. the Yukon-Northwest Seismic Network, Canadian Rockies and Alberta Network), national and regional networks, and past seismological datasets, new studies now achieve improved resolution across large regions of western Canada and the craton-Cordillera transition. We present a new vertically polarized shear speed model of the lithospheric mantle and crust across western North America, and examine key features associated with the complex crust and lithosphere of dynamics of western North America. These include the location and nature of the Cordillera-Craton transition throughout the Cordillera, and what role the apparent step

  17. Large Clockwise Rotations In The Fore-arc of Northern Chile

    Science.gov (United States)

    Arriagada, C.; Fernandez, R.; Roperch, P.; Mpodozis, C.; Cobbold, P. R.

    Obliquely convergent plate boundaries typically exhibit wide zones of deformation characterized by block rotations and complex patterns of contractional, extensional, and strike-slip faulting. In the overriding plate the trench-parallel component of dis- placement commonly occurs on strike-slip faults that dissect the fore-arc into elongate slivers by displacements subparallel to the boundary. However, differences in the pat- tern of strain partitioning along the fore-arc, may produce complex structural zones oblique to the mean strike-slip faults. In northern Chile, the Domeyko Fault System in the Chilean Precordillera is often described as a major strike-slip system due to oblique convergence between Nazca and South America plates. In this context , we have carried out a paleomagnetic study in the fore-arc, southward of the Arica elbow (Antofagasta-Copiapo region, 22-27 degrees South). We sampled about 250 sites from Mezosoic-Paleogene units constituted mainly by volcanic and sedimentary rocks and few intrusives. The results show extensive and large clockwise tectonic rotations up to 65 degrees. Rotations are not only related to the Domeyko Fault System, but are widely observed across the fore-arc. Paleomagnetic results from Mezosoic-Paleogene rocks contrast with those obtained in sedimentary and volcanic Neogene sequences for which no or little evidence of tectonic rotation is found. We cannot discard the hypothesis that rotations in Jurassic and Cretaceous rocks of the Coastal Cordillera are older than rotations observed in Paleogene units. This interpretation would sug- gest that a long-lasting (late Cretaceous to Oligocene) tectonic mechanism inducing clockwise rotations has been acting during the eastward migration of the volcanic arc. An other interpretation is that the tectonic rotations occurred mostly during the late Paleogene across the whole fore-arc as suggested by the observation of major faults oblique to the mainly N-S Domeyko Fault System. The

  18. Nautiloideos del Triásico Medio en la Cordillera Ibérica y en la parte oriental de las Cordilleras Béticas

    OpenAIRE

    Goy Goy, A.; Martínez, G.

    1996-01-01

    [ES] En el presente trabajo se dan a conocer las sucesiones de los nautiloideos obtenidos en cada una de las cuencas estudiadas, así como sus implicaciones biocronoestratigráficas. En la parte oriental de las Cordilleras Béticas existe el siguiente registro de nautiloideos: — Grypoceras cf? privatum (MOJSISOVICS). Parte inferior del Muschelkalk en Quipar (Murcia). — Germanonautilus bidorsatus (SCHLOTI-{EIM); Mojsvaroceras cf? kummeli PARNES; fudonautifus cf? awadi KUMM...

  19. Evaporite deposits of Bogota area, Cordillera Oriental, Colombia

    Science.gov (United States)

    McLaughlin, Donald H.

    1972-01-01

    Four evaporite-bearing stratigraphic zones are known in Cretaceous strata of the Cordillera Oriental of Colombia north and east of Bogota. The easternmost and oldest zone is probably of Berriasian to Valanginian age. The next oldest is probably late Barremian to early Aptian in age. The third appears to be Aptian. The westernmost and best known sequence in the Sabana de Bogota is Turonian to early Coniacian in age. This youngest sequence contains the thickest salt deposits known in Colombia and is probably the most widespread geographically.Most of the rock salt exposed in the three accessible mines (at Zipaquira, Nemocon, and Upin) has a characteristic lamination of alternating slightly argillaceous and highly argillaceous salt layers of varied but moderate thickness. Black, calcareous claystone, commonly very pyritic, is interbedded conformably with the laminated salt in many places throughout the deposits. Fragments of black claystone derived from the thinner interbeds are ubiquitous in all deposits, both as concordant breccia zones and as isolated clasts.Anhydrite is scarce at Zipaquira and apparently even rarer at Nemocon and Upin. Gypsum is produced at three small deposits in the oldest evaporite zone where it probably was concentrated by leaching of salt initially associated with it.The two intervening evaporite zones are not exposed, but their existence and distribution are indicated by brine springs and locally by "rute," a distinctive black, calcareous mud formed by the leaching of salt beds.Fossils show that the youngest salt-claystone zone, in the Sabana de Bogota, is contemporary with associated hematitic sandstone and siltstone, and with carbonaceous and locally coaly claystone. Although evidence is poor, this same facies relation probably exists within the other three evaporite zones.All salt deposits in this study probably are associated with anticlines, a relation best exemplified by the deposits on the Sabana de Bogota. Within these anticlines the

  20. Orogenesis at the southern tip of the Americas: the structural evolution of the Cordillera Darwin metamorphic complex, southernmost Chile

    Science.gov (United States)

    Cunningham, W. Dickson

    1995-04-01

    New, detailed lithologic and structural data are presented from three separately mapped areas along the southern boundary of the Cordillera Darwin metamorphic complex of southernmost Chile. Cordillera Darwin is a unique uplift because it exposes the highest grade rocks in the Andes south of Peru and averages 1 km higher in elevation than adjacent areas. The structural data indicate that Cordillera Darwin experienced mid-Late Cretaceous trans-pressional deformation with a partitioned strike-slip component localized along the Beagle Channel that forms the southern boundary to the range. Foliation, lineation and fold axis trends indicate NE-SW-directed contraction and NW-SE strike-slip shearing (present directions) during progressive {D1}/{D2} Andean deformation. D2 deformation is marked by outcrop-to 10 km-scale south-southwest-vergent folds. Late Cretaceous-Tertiary brittle-ductile and brittle left-lateral strike-slip faults and shear zones crosscut all {D1}/{D2} structures. Although limited structural evidence for extensional tectonics was documented in this study, apparent normal offsets across both arms of the Beagle Channel and previously documented field evidence for extension from other areas in Cordillera Darwin suggest that transtensional displacements also may have occurred in southern Cordillera Darwin during the Late Cretaceous-Early Tertiary. Cordillera Darwin's position within the evolving Patagonian Orocline adjacent to an evolving Mesozoic-Cenozoic left-lateral transform boundary between the South American and Antarctic plates, and later the South American and Scotia plates, necessitates consideration of the possible effects of regional counterclockwise rotation on development of structures. Regional counterclockwise rotation of Cordillera Darwin may have controlled the temporal and spatial transition of deformational regimes within Cordillera Darwin. Exhumation of the metamorphic core of Cordillera Darwin during the Late Cretaceous-Early Tertiary is

  1. Petrografic description of some igneous rocks from the Cordillera of South Mendoza, in the Argentine

    NARCIS (Netherlands)

    Kuenen, Ph.H.

    1926-01-01

    Comparatively little is yet known of the intricate igneous history of the Cordillera of South Mendoza. Almost all the knowledge we have is due to the field- and stratigraphical work of Dr. H. Gerth of Leiden (bibl. 1 and 2), and the petrographic studies of Dr. H. G. Backlund (bibl. 3 and 4) on the

  2. Population Declines of Mountain Coqui (Eleutherodactylus portoricensis) in the Cordillera Central of Puerto Rico

    Science.gov (United States)

    Barker, Brittany S.; Ríos-Franceschi, Alejandro

    2014-01-01

    The Mountain Coqui (Eleutherodactylus portoricensis) is a frog endemic to montane rainforests in the Cordillera Central and Luquillo Mountains of Puerto Rico. Classified as endangered by the IUCN Red List and as vulnerable by the Department of Natural and Environmental Resources of Puerto Rico, this species has undergone considerable decline in the Luquillo Mountains. To evaluate the population status of E. portoricensis across its entire range, we conducted ~87 hours of surveys at 18 historical localities and 25 additional localities that we considered suitable for this species. We generated occupancy models to estimate the probability of occurrence at surveyed sites and to identify geographic and climatic factors affecting site occupancy. We also constructed a suitability map to visualize population status in relation to the presence of land cover at elevations where the species has been documented, and determined the dates when populations were last detected at historical localities. Eleutherodactylus portoricensis was detected at 14 of 43 localities, including 10 of 18 historical localities, but it was not detected at any localities west of Aibonito (western Cordillera Central). Occupancy models estimated the probability of occurrence for localities in the western Cordillera Central as zero. Site occupancy was positively associated with montane cloud forest, and negatively associated with the western Cordillera Central, maximum temperature, and precipitation seasonality. The suitability map suggests that declines have occurred despite the presence of suitable habitat. We suggest upgrading the extinction risk of E. portoricensis and potentially developing a captive breeding program for this species. PMID:25685250

  3. Palynology of cushion bogs of the Cordillera Pelada, Province of Valdivia, Chile

    Science.gov (United States)

    Heusser, Calvin J.

    1982-01-01

    Fossil pollen identified in the earliest sediments of three cushion bogs in the Cordillera Pelada (40°10'S, 73°30'W) dated 10,425 14C yr B.P. includes the subantarctic species Dacrydium fonckii, Tetroncium magellanicum, Astelia pumila, Gaimardia australis, Donatia fascicularis, and Drosera uniflora. All grow today in the Cordillera Pelada and range poleward to the southernmost Province of Magallanes; one species, Drapetes muscosa, included with the pollen of these plants in the earliest record, is no longer a constituent of the flora but is limited only to subantarctic Chile. Available evidence indicates that plants survived the last glaciation north of the glacial border with the course of postglacial migration southward following the wastage of the glacier complex. Holocene climatic and vegetational changes in the Cordillera Pelada are interpreted in the context of regional reconstructions which show maximum warmth about 9000 yr ago with a pronounced dry period lasting from 9000 to 6500 yr B.P. Maximum precipitation was later reached around 4000 yr ago but has decreased overall since then. The regional decline of the endemic gymnosperm Fitzroya cupressoides, which today is extensively destroyed in the Cordillera Pelada, follows this decrease in precipitation. These climatic data suggest a net south ward shift in the zone of westerly winds that bring rainfall to the region over the past 4000 yr.

  4. Ethno–botanical survey of edible wild fruits in Benguet, Cordillera administrative region, the Philippines

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    Racquel Tan Chua-Barcelo

    2014-05-01

    Conclusions: Benguet province in the Cordillera region provides a diversity of edible wild fruits. The data gathered from the study signifies that collection, processing and utilization of edible wild fruits are still part of the daily activities of the people in Benguet.

  5. Triassic paleomagnetic data from the subbetic and the malaguide complex of the betic cordilleras (Southeast Spain)

    NARCIS (Netherlands)

    Vandenberg, J.; Mäkel, G.H.; Rondeel, H.E.

    1984-01-01

    The analysis of Triassic paleomagnetic directions from the Betic Cordilleras in southeast Spain indicates a considerable amount of relative displacement of the Subbetic of the External Zone of this orogen with respect to the Iberian block. The paleomagnetic pole positions of the Malaguide Complex of

  6. Triassic paleomagnetic data from the subbetic and the malaguide complex of the Betic Cordilleras (Southeast Spain)

    NARCIS (Netherlands)

    Makel, G.H.; Rondeel, H.E.; Vandenberg, Jorgen

    1984-01-01

    The analysis of Triassic paleomagnetic directions from the Betic Cordilleras in southeast Spain indicates a considerable amount of relative displacement of the Subbetic of the External Zone of this orogen with respect to the Iberian block. The paleomagnetic pole positions of the Malaguide Complex

  7. Stress field evolution above the Peruvian flat-slab (Cordillera Blanca, northern Peru)

    Science.gov (United States)

    Margirier, A.; Audin, L.; Robert, X.; Pêcher, A.; Schwartz, S.

    2017-08-01

    In subduction settings, the tectonic regime of the overriding plate is closely related to the geometry of the subducting plate. Flat-slab segments are supposed to increase coupling at the plate interface in the Andes, resulting in an increase and eastward migration of the shortening in the overriding plate. Above the Peruvian flat-slab, a 200 km-long normal fault trend parallel to the range and delimits the western flank of the Cordillera Blanca. In a context of flat subduction, expected to produce shortening, the presence of the Cordillera Blanca normal fault (CBNF) is surprising. We performed a systematic inversion of striated fault planes in the Cordillera Blanca region to better characterize the stress field above the Peruvian flat-slab. It evidences the succession of different tectonic regimes. NE-SW extension is predominant in most of the sites indicating a regional extension. We suggest that the Peruvian flat-slab trigger extension in the Western Cordillera while the shortening migrated eastward. Finally, we propose that flat-slab segments do not increase the coupling at the trench neither the shortening in the overriding plate but only favor shortening migration backward. However, the stress field of the overriding plate arises from the evolution of plate interface properties through time due to bathymetric anomaly migration.

  8. Pseudofurnishius (Conodonta) in the Triassic of the Betic Cordilleras, SE Spain

    NARCIS (Netherlands)

    Boogaard, van den M.; Simon, O.J.

    1973-01-01

    The stratigraphical position and the fossil content of several Triassic carbonate beds in the Betic Cordilleras are described. Three different conodont faunas have been found: one with Pseudofurnishius murcianus as the dominant species, a second in which Pseudofurnishius murcianus occurs together

  9. Diversidad y biomasa de macro-invertebrados en matrices intermareales del tunicado Pyura praeputialis (Heller, 1878 en la Bahía de Antofagasta, Chile Diversity and biomass of macro-invertebrates in intertidal matrices of the tunicate Pyura praeputialis (Heller, 1878 in the Bay of Antofagasta, Chile

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    MAURICIO CERDA

    2001-12-01

    Full Text Available Se analiza la diversidad biológica y biomasa de macro-invertebrados asociados a los mantos intermareales del tunicado Pyura praeputialis (Heller, 1878 en la Bahía de Antofagasta, donde la especie se encuentra casi exclusivamente confinada a lo largo de aproximadamente 70 km de extensión costera de dicha bahía. En la bahía se seleccionaron tres sitios para el análisis de los mantos de piures: uno localizado aproximadamente en el centro de la distribución del tunicado y dos cercanos a los límites norte y sur (ecotonos de dicha distribución. La arquitectura de las matrices de piures genera substrato secundario y bio-hábitat que corresponden a los de una especie bio-ingeniera ecosistémica. En las matrices se encontró una diversidad gama de 96 taxa de macro-invertebrados, pertenecientes a nueve phyla. Entre ellos destaca la riqueza de gastrópodos (28 %, poliquetos (26 %, decápodos (15 % y bivalvos (14 %. Para los macro-invertebrados se registró una biomasa promedio de 246,40 g m-2 . Los atributos de diversidad y biomasa de macro-invertebrados no presentaron diferencias significativas entre sitios, lo cual sugiere que el efecto de estas matrices sobre la diversidad y biomasa de los macro-invertebrados es similar a lo largo del rango de distribución dentro de la bahía. Los resultados son discutidos en términos de los patrones de biodiversidad de macro-invertebrados, sus biomasas y el rol que juega P. praeputialis como especie bio-ingeniera en la zona costera de la Bahía de Antofagasta. Se realizan comparaciones con un estudio similar realizado en mantos de Pyura stolonifera en Natal, Sudáfrica y respecto de la biodiversidad de invertebrados asociadas a otras especies bio-ingenierasThe study was conducted to analyze the biological diversity and biomass of macro-invertebrates in intertidal matrices of Pyura praeputialis (Heller, 1878 in the Bahía de Antofagasta, where the species is confined along approximately 70 km of coastline

  10. Diversidad y patrones de distribución geográfica de insectos coleópteros en ecosistemas desérticos de la región de Antofagasta, Chile Diversity and geographic distribution patterns of coleopteran insects in desert ecosystems of the Antofagasta region, Chile

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    VIVIANE JEREZ

    2000-03-01

    Full Text Available La fauna coleopterológica de la Región de Antofagasta, ha sido objeto de diversos trabajos, pero hasta el momento falta un análisis de conjunto de la diversidad y distribución espacial de las especies. En este trabajo se da a conocer la diversidad de Coleoptera, rangos de distribución de las especies y se analiza las relaciones biogeográficas que pueden existir entre los distintos ecosistemas descritos para la Región. Para ello se elaboró un catastro georreferenciado en base a revisión bibliográfica, material de colección y prospecciones en terreno. La distribución espacial de los taxa se estableció en relación a 11 ecosistemas descritos para la Región y se determinaron áreas de endemismo mediante análisis de parsimonia biogeográfico. La composición taxonómica de Coleoptera está formada por 21 familias, 86 géneros y 167 especies, siendo Tenebrionidae la familia más diversa con 23 géneros y 78 especies. Los ecosistemas que presentan mayor diversidad específica son Estepa subdesértica de la puna (52 sp., Desierto costero de Tocopilla (50 sp., Desierto del Salar de Atacama (35 sp., Desierto costero de Taltal (32 sp., Desierto de los aluviones (22 sp. y Estepa arbustiva (17 sp.. Sin embargo los ecosistemas que concentran el mayor porcentaje de endemismo son Desierto costero de Tocopilla (72%, Desierto costero de Taltal (62,5%, Estepa subdesértica de la puna (55,8%, Desierto del Salar de Atacama (51,4 %, Estepa arbustiva (47% y Desierto de los aluviones (36,3%. Se delimitaron tres áreas de endemismo para la Región de Antofagasta y que corresponden a tres grandes ecosistemas distribuidos en un gradiente altitudinal: Desierto litoral, Desierto de los aluviones y Zona tropicalThe coleopterologic fauna of the Antofagasta Region has been the object of diverse studies, but until now, an analysis of both the diversity and spatial distribution of the species was lacking. In this paper, the diversity of coleopteran species and

  11. Structure of the Sierra de Lujar (Alpujarride Complex, Betic Cordillera

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    Sanz de Galdeano, Carlos

    2014-06-01

    Full Text Available The Sierra de Lujar constitutes one of the best examples of fold superposition of the Internal Zone of the Betic Cordillera (S Spain. In this paper, the members of its Triassic carbonate series have been used for the first time to obtain the cartography of the Sierra de Lujar, providing knowledge of the two folding systems, the older trending E-W and the younger (far better represented, NNE-SSW. The most important fold is a large reverse syncline with a convex axis towards the SE, forming part of the S and E edges of this sierra; contrarily, the vergence is towards the N in the southern sector and towards the W in the eastern sector. The interior of the Sierra de Lujar bears a succession of NNE-SSO anticlinal and synclinal folds, some with reverse limbs. The vergences fluctuate, even within the same fold. Folds of an E-W system crop out only in the SW sector of the Sierra de Lujar and verge to the S. The unit of the Sierra de Lujar (Lujar-Gádor unit is overthrust by the Escalate unit (which is a duplication of the Lujar unit and by other upper units, formed here by schists. The W edge of the Sierra de Lujar is affected by a large normal fault that sinks the Escalate unit there. The E-W folds were coetaneous with the thrusting of the units, while those in the NNE-SSW direction formed at the onset of the westward shift of the Internal Betic-Rif Zone.La Sierra de Lújar constituye uno de los mejores ejemplos de superposición de pliegues de la Zona Interna Bética. Su estructura se ha determinado a partir del primer mapa en el que se han distinguido los diferentes tramos de su serie triásica carbonatada. Los pliegues NNE-SSO son los más abundantes y se superponen a otros de dirección E-O. Los bordes S y E de esta sierra corresponden en parte a un gran sinclinal invertido vergente hacia su interior y que continúa en la Sierra de La Joya pero con distinta vergencia. En el interior de la sierra hay numerosos anticlinales y sinclinales de direcci

  12. Regional Analysis of the Hazard Level of Glacial Lakes in the Cordillera Blanca, Peru

    Science.gov (United States)

    Chisolm, Rachel E.; Jhon Sanchez Leon, Walter; McKinney, Daene C.; Cochachin Rapre, Alejo

    2016-04-01

    The Cordillera Blanca mountain range is the highest in Peru and contains many of the world's tropical glaciers. This region is severely impacted by climate change causing accelerated glacier retreat. Secondary impacts of climate change on glacier retreat include stress on water resources and the risk of glacial lake outburst floods (GLOFs) from the many lakes that are forming and growing at the base of glaciers. A number of GLOFs originating from lakes in the Cordillera Blanca have occurred over the last century, several of which have had catastrophic impacts on cities and communities downstream. Glaciologists and engineers in Peru have been studying the lakes of the Cordillera Blanca for many years and have identified several lakes that are considered dangerous. However, a systematic analysis of all the lakes in the Cordillera Blanca has never before been attempted. Some methodologies for this type of systematic analysis have been proposed (eg. Emmer and Vilimek 2014; Wang, et al. 2011), but as yet they have only been applied to a few select lakes in the Cordillera Blanca. This study uses remotely sensed data to study all of the lakes of the Glacial Lake Inventory published by the Glaciology and Water Resources Unit of Peru's National Water Authority (UGRH 2011). The objective of this study is to assign a level of potential hazard to each glacial lake in the Cordillera Blanca and to ascertain if any of the lakes beyond those that have already been studied might pose a danger to nearby populations. A number of parameters of analysis, both quantitative and qualitative, have been selected to assess the hazard level of each glacial lake in the Cordillera Blanca using digital elevation models, satellite imagery, and glacier outlines. These parameters are then combined to come up with a preliminary assessment of the hazard level of each lake; the equation weighting each parameter draws on previously published methodologies but is tailored to the regional characteristics

  13. Una nueva especie de Atelopus A.M.C. Dumeril & Bibron 1841 (Amphibia: Bulonidae de la cordillera Occidental, Colombia

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    Ruiz Carranza Pedro M.

    1995-11-01

    Full Text Available A new species of the genus Atelopus of the longirostris Group (A.negreti is nomined and described from the Eastern slope of the Cordillera Occidental, S. P.N.N. Munchique, Cauca, at 1470-1580m.Se nomina y describe una nueva especie de atelopus del grupo longirostris: A.negreti del flanco occidental de la Cordillera Occidental, límite S. del Parque Nacional Natural Munchique, Cauca, 1470-1580m.

  14. Long-term dynamics (1990 to 2004 of the polychaete fauna from the sublittoral soft-bottoms off Punta Coloso (Antofagasta, northern Chile

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    Franklin D. Carrasco

    2006-12-01

    Full Text Available Long-term monitoring (1990 to 2004 at four stations (50 to 60 m depth off Punta Coloso, Antofagasta, northern Chile, has allowed us to study temporal changes in the sublittoral macrobenthic polychaete infauna composition and abundance. The numerical contribution of the polychaete fraction to the total fauna was high (65 to 93%, whereas biomass was smaller and variable (20 to 85%. The number of invertebrate species collected per cruise was relatively low (40 to 90 species and the number of polychaete species ranged from 18 to 37 per cruise (mean = 29.9, with a cumulative number of 56 polychaete species. The most abundant species collected included the small-sized Aricidea pigmentata Carrasco (26.5%, Magelona phyllisae Jones (22.7%, Paraprionospio pinnata (Ehlers (13.5%, Tharyx longisetosa Hartmann-Schröder (12.1%, and Prionospio peruana Hartmann-Schröder (11.8%. Clear general patterns or tendencies are not seen in temporal variations of polychaete fauna nor when analyzing the seasons individually. P. pinnata was the only dominant species to show a general tendency in abundance fluctuations. Although the study period included two El Niño events (1991-1992 and 1997-1998, a clear dynamic was not seen in either abundance or dominant species. The analyzed data validate or corroborate high stability or persistence over time that has been suggested for polychaete fauna in the study area. Such stability or persistence exists in spite of high seasonal variability and interannual fluctuations in the region’s oceanographic conditions.

  15. Amphibia, Anura, Strabomantidae, Pristimantis palmeri Boulenger, 1912: Distribution extension for the Central Cordillera, Colombia

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    Bolivar-G, W.

    2011-01-01

    Full Text Available We report a new locality record for Pristimantis palmeri, an endemic species to Colombia associated to forestand weeds in open areas of Choco, Risaralda, Quindío, Valle del Cauca, and Cauca (900 – 2,400 m.a.s.l.. This report expandsits geographical distribution in 177 km toward south and suggests the existence of a discontinuous distribution in thewestern slope of the Central Cordillera of Colombia.

  16. Three new species of Eleutherodactylus (Amphibia: Leptodactylidae from high elevations of the cordillera Central of Colombia

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    Lynch John D.

    1996-11-01

    Full Text Available A new species of the Eleutherodactylus orcesi group, the smallest member of the group, is described from the Páramo de los Valles (Tolima. It is very similar to E. slmoterus. From the same locality, a new species of dwarf Eleutherodactylus, lacking a tympanum, is described. It appears to be a member of the E. myersi group. Lastly, a new large black Eleutherodactylusis described from páramo and subpáramo habitats of the Cordillera Central. This species is distributed from Antioquia to Cauca. With these three species, fifteen species of Eleutherodactylus are known for páramo and subpáramo habitats of the Cordillera Central north of the Macizo de Pasto. These 15 species be long to tour species groups.Se describe una especie nueva del grupo de Eleutherodactylus orcesi del Páramo de los Valles (Tolima. Esta especie es muy parecida a E. simoterus pero se distingue por su tamaño (la especie nueva es la más pequeña del grupo. Se describe también una especie enanita del Páramo de los Valles que posiblemente es una especie del grupo de Eleutherodactylus myersl. La especie es muy distinta porque carece de tímpano. Finalmente, se describe una especie grande y negra que se encuentra desde Antioquia hacia Cauca en la Cordillera Central. Con estas especies, tenemos 15 especies de Eleutherodactylus conocidas de los páramos y subpáramos de la Cordillera Central al norte del Macizo de Pasto, que pertenecen a cuatro grupos de especies.

  17. ZOOARQUEOLOGÍA Y TAFONOMÍA DEL PERÍODO TARDÍO-INCA EN PEÑAS COLORADAS, ANTOFAGASTA DE LA SIERRA (PUNA DE CATAMARCA, ARGENTINA/Zooarchaeology and taphonomy of the Late Period-INCA in Peñas Coloradas, Antofagasta de la Sierra (Puna of Catamarca, Argentina

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    Jorge Guillermo Ortiz

    2012-11-01

    Full Text Available Se presenta el análisis integrado del conjunto arqueofaunístico, constituido por vertebrados e invertebrados, del sitio Peñas Coloradas 3-cumbre (PC3-c, Antofagasta de la Sierra (Catamarca, Argentina. El sitio se localiza en la cumbre de un farallón de ignimbrita y está conformado por estructuras arquitectónicas asignadas a momentos Tardíos-Incas, algunas de las cuales han sido reutilizadas hasta principios del siglo XX. Con la finalidad de complementar los datos y reconstruir la historia tafonómica de los conjuntos faunísticos, se estudió el contexto sedimentario mediante métodos físico-químicos (textura; pH; determinación de albúmina, P y MO. Los materiales analizados brindaron datos sobre algunas de las actividades realizadas en las estructuras, el consumo de animales, temporalidad, estacionalidad de las ocupaciones, y sobre los procesos diagenéticos actuantes. La integración contextual de los datos materiales analizados y del emplazamiento del sitio y sus estructuras, nos permite inferir prácticas sociales diferenciadas entre las estructuras con cubierta y sin cubierta. Las primeras, se vinculan a depósitos de alimentos y manufacturas, mientras que las segundas se asocian con  prácticas residenciales, procesamiento y consumo de alimentos. Abstract In this paper, an integrated analysis of archaeofaunal data consisting of vertebrates and invertebrates of the Peñas Coloradas 3-summit (PC3-c, Antofagasta de la Sierra (Catamarca, Argentina is conducted. The site is located at the top of an ignimbrite hill and is composed of architectural structures attributed to Late Inca times, some of which had been re-used until the early 20th century. In order to complement the data and reconstruct the taphonomic history of the faunal assemblages, we studied the sedimentary context by physicochemical methods (texture, pH, determination of albumin, P and MO. The material tested has provided data on some of the activities in the structures

  18. Rotación cenozoica de la Cordillera Occidental peruana y levantamiento de los Andes Centrales

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    1992-01-01

    Full Text Available ROTATION CENOZOÏQUE DE LA CORDILLERE OCCIDENTALE PERUVIENNE ET SURRECTION DES ANDES CENTRALES. Une étude paléomagnétique a été réalisée dans la région de Lima (Pérou sur 39 sites fiables parmi 55 (564 carottes d’âge crétacé moyen à miocène supérieur distribués le long de trois transects NE-SW qui recoupent l’ensemble de la Cordillère Occidentale des Andes Centrales. Sur l’ensemble de ce secteur d’étude, toutes les déclinaisons paléomagnétiques mesurées sont cohérentes entre elles et systématiquement déviées vers l’Ouest. Elles démontrent ainsi l’existence d’une rotation antihoraire de l’ensemble de la Cordillère Occidentale par rapport au continent sud-américain stable. L’amplitude de cette rotation est de 16° ± 6° après le Crétacé et de 13,7° ± 8,1° après l’Eocène. Ces résultats inédits sont en bon accord avec ceux précédemment obtenus sur les Andes Centrales péruviennes et confortent le modèle récemment proposé pour expliquer l’édification et la surrection des Andes Centrales. Se ha realizado un estudio paleomagnético en la región de Lima (Perú a partir de 39 estaciones de muestreo fiables sobre un total de 55 (564 muestras de edad cretácea media a miocena superior distribuidas a lo largo de tres transectas NE-SW que cortan la Cordillera Occidental de los Andes Centrales. Para el sector estudiado, todas las declinaciones paleomagnéticas medidas son coherentes entre ellas y sistemáticamente desviadas hacia el oeste. Ello demuestra la existencia de una rotación antihoraria del conjunto de la Cordillera Occidental, respecto al continente sudamericano estable. Dicha rotación presenta una amplitud de 16° ± 6° posterior al Cretáceo, y de 13.7° ± 8.1° posterior al Eoceno. Estos resultados inéditos están de acuerdo con aquellos anteriormente obtenidos sobre los Andes Centrales peruanos y refuerzan el modelo recientemente propuesto para explicar la edificación y el

  19. Tipos de vegetación del llano de paletará. cordillera central colombia

    OpenAIRE

    Restrepo, Carla; Duque, Andrés

    2012-01-01

    Se estudiaron los tipos de vegetación del Llano de Paletará, municipio de Coconuco, departamento del Cauca, Colombia. Basados en la fisonomía y composición florística de la vegetación identificamos 8 tipos de vegetación, los cuales representan los tipos de vegetación paramunos de carácter azonal más extensos de la Cordillera Central registrados hasta el momento. De los 8 tipos de vegetación, cuatro son de porte herbáceo (''frailejonalpajonal'' con Espeletia. "chuscal abierto" con Chusquea. "p...

  20. Surgimiento de nuevas formas de violencias urbanas en Pereira : Caso Organización la Cordillera

    OpenAIRE

    García Hernández, Luis Ernesto

    2012-01-01

    El presente trabajo de investigación contiene la presentación de los resultados de la indagación sobre el fenómeno de nuevas violencias urbanas. El estudio se realizó en la ciudad de Pereira (Risaralda), sobre las nuevas formas de organización criminal, representada por la Organización la Cordillera, en el manejo del narcotráfico, narcomenudeo y violencia cotidiana en los barrios marginales de la ciudad. Específicamente, el estudio se centra en indagar las neo violencias monopolizadas por est...

  1. Incadendron : a new genus of Euphorbiaceae tribe Hippomaneae from the sub-Andean cordilleras of Ecuador and Peru

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    Kenneth J. Wurdack

    2017-08-01

    Full Text Available Incadendron esseri K.Wurdack & Farfan, gen. & sp. nov., from the wet sub-Andean cordilleras of Ecuador (Cordillera del Cóndor and Peru (Cusco, Oxapampa is described and illustrated. This recently discovered large canopy tree with a narrow elevational range presents an unusual combination of rare morphological characters in Hippomaneae including mucilage-secreting sheathing stipules, conduplicate ptyxis, and large, woody fruits. The broader significance of these characters in Hippomaneae is discussed. The morphology and anatomy of Incadendron were investigated, highlighting its fruit similarities with Guiana Shield endemic Senefelderopsis, and the systematics value of ptyxis variation, which remains poorly studied for the family.

  2. Resolving the tectonic transition between ancestral North America and the northern Cordillera

    Science.gov (United States)

    Schaeffer, A. J.; Audet, P.; Lebedev, S.

    2015-12-01

    The northern Cordillera, situated in the Canadian northwest, is one of the most actively deforming regions in Canada and host to the highest earthquake activity in the country. Furthermore, it presents a largely contiguous snapshot through almost 4 Gyr of Earth's history across a zone architecture are expected. Additionally, significant seismicity is observed further north off the Beaufort Shelf; however, its relationship to the regional stress fields and associated tectonic forcing is unclear. Despite the high seismicity levels across, detailed study of this region has been limited by insufficient coverage of seismological infrastructure, hindering resolution in past models. With the deployment of the USArray Transportable Array in Alaska over the last several years, combined with regional arrays such as the Yukon-Northwest Seismic Network (YNSN), Banks Island Seismic Network (BISN) and Mackenzie Mountains Experiment, new studies will leverage these datasets enabling more detailed imaging of the structure and seismicity across the region. Here we present a new high-resolution, vertically polarized shear speed and azimuthal model of northwestern Canada and Alaska, constrained by vertical component seismogram fits computed using the Automated Multimode Inversion of Surface, S, and multiple-S waveforms. With this new model, we aim to address key questions relating to the dynamics of the northern Cordillera, including how far west the craton edge extends at depth, in addition to the crustal thickness, velocity structure, and pattern of crustal fabrics around major faults throughout the region.

  3. Latest extension of the Laujar fault in a convergence setting (Sierra Nevada, Betic Cordillera)

    Science.gov (United States)

    Martínez-Martos, Manuel; Galindo-Zaldívar, Jesus; Sanz de Galdeano, Carlos; García-Tortosa, Francisco Juan; Martínez-Moreno, Francisco José; Ruano, Patricia; González-Castillo, Lourdes; Azañón, José Miguel

    2017-02-01

    The present-day relief of the Betic Cordillera formed since the Late Miocene through the regional N-S to NW-SE Africa-Eurasia convergence that developed large folds. The Laujar Fault Zone is a south-dipping E-W oriented structure located at the northern boundary of the Alpujarran Corridor Neogene intramontane basin, which separates Sierra Nevada and Sierra de Gador antiforms, in the Internal Zones of the Betic Cordillera. The fault zone acted in a first stage as a dextral strike-slip fault. Currently it moves as a normal fault evidenced by striated calcretes, also in agreement with regional continuous GPS (CGPS) data that support the hypothesis of an active N-S extension in the fault area. In order to analyse the deep geometry of the Laujar Fault Zone, we combined several geophysical techniques (gravity, magnetic, electric resistivity tomography and audio-magnetotelluric data) with field geological observations. Fault surfaces seem to join at a southward-dipping shallow detachment level, including faults covered by the sedimentary infill. The fault zone was developed in a previously weakened area by wrench faults parallel to the Alpujarran Corridor. The recent normal activity of this fault zone may be a consequence of a change in the Africa-Eurasia convergence orientation, which implies a decrease in the N-S compression component. This structure along the southern limb of Sierra Nevada antiform evidences the gravitational collapse of previously thickened crust in a regional compressional context simultaneous to metamorphic core uplift.

  4. Geomorphologically effective floods from moraine-dammed lakes in the Cordillera Blanca, Peru

    Science.gov (United States)

    Emmer, Adam

    2017-12-01

    Outburst floods originating in moraine-dammed lakes represent a significant geomorphological process as well as a specific type of threat for local communities in the Cordillera Blanca, Peru (8.5°-10° S; 77°-78° W). An exceptional concentration of catastrophic floods has been reported from the Cordillera Blanca in the first half of 20th Century (1930s-1950s), leading to thousands of fatalities. The main objective of this paper is to provide a revised and comprehensive overview of geomorphologically effective floods in the area of interest, using various documentary data sources, verified by analysis of remotely sensed images (1948-2013) and enhanced by original field data. Verified events (n = 28; 4 not mentioned before) are analysed from the perspective of spatiotemporal distribution, pre-flood conditions, causes, mechanisms and geomorphological impacts as well as socioeconomical consequences, revealing certain patterns and similar features. GLOFs are further classified according to their magnitude: 5 extreme events, 8 major events and 15 minor events are distinguished, referring to the quantified geomorphological and socioeconomical impacts. Selected moraine dams and flood deposits are dated using lichenometric dating. Special attention is given to moraine dam breaches - the most frequent type of water release with the most significant consequences. Selected major events and their consequences are studied in detail in a separate section. Finally, a general schematic model of lake formation, growth and post-flood evolution reflecting initial topographical setting and glacier retreat is introduced and the utilization of the obtained results is outlined.

  5. Forecasting typhoid fever incidence in the Cordillera administrative region in the Philippines using seasonal ARIMA models

    Science.gov (United States)

    Cawiding, Olive R.; Natividad, Gina May R.; Bato, Crisostomo V.; Addawe, Rizavel C.

    2017-11-01

    The prevalence of typhoid fever in developing countries such as the Philippines calls for a need for accurate forecasting of the disease. This will be of great assistance in strategic disease prevention. This paper presents a development of useful models that predict the behavior of typhoid fever incidence based on the monthly incidence in the provinces of the Cordillera Administrative Region from 2010 to 2015 using univariate time series analysis. The data used was obtained from the Cordillera Office of the Department of Health (DOH-CAR). Seasonal autoregressive moving average (SARIMA) models were used to incorporate the seasonality of the data. A comparison of the results of the obtained models revealed that the SARIMA (1,1,7)(0,0,1)12 with a fixed coefficient at the seventh lag produces the smallest root mean square error (RMSE), mean absolute error (MAE), Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC). The model suggested that for the year 2016, the number of cases would increase from the months of July to September and have a drop in December. This was then validated using the data collected from January 2016 to December 2016.

  6. Grain size distribution of soils within the Cordillera Blanca, Peru: An indicator of basic mechanical properties for slope stability evaluation

    Czech Academy of Sciences Publication Activity Database

    Novotný, J.; Klimeš, Jan

    2014-01-01

    Roč. 11, č. 3 (2014), s. 563-577 ISSN 1672-6316 R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : moraines * grain size distribution * shear strength * hydraulic conductivity * Cordillera Blanca Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 0.963, year: 2014

  7. Rare Moss-Built Microterraces in a High-Altitude, Acid Mine Drainage-Polluted Stream (Cordillera Negra, Peru)

    NARCIS (Netherlands)

    Sevink, J.; Verstraten, J.M.; Kooijman, A.M.; Loayza-Muro, R.A.; Hoitinga, L.; Palomino, E.J.; Jansen, B.

    2015-01-01

    The Rio Santiago in the Cordillera Negra of Peru is severely contaminated by acid mine drainage in its headwaters. In a strongly acid stream, at about 3800 m above sea level (masl), microterraces were found with terrace walls built up of dead moss, with encrustations and interstitial fine, creamy

  8. Ecología trófica de los ostreros Haematopus palliatus pitanay (Murphy 1925 y Haematopus ater (Vieillot et Oudart 1825 en mantos del tunicado Pyura praeputialis (Heller 1878 en la Bahía de Antofagasta, Chile Trophic ecology of the oystercatchers Haematopus palliatus pitanay (Murphy 1925 and Haematopus ater (Vieillot et Oudart 1825 on beds of the tunicate Pyura praeputialis (Heller 1878 in the Bay of Antofagasta, Chile

    Directory of Open Access Journals (Sweden)

    CRISTIAN J. PACHECO

    2000-09-01

    Full Text Available En Antofagasta, norte de Chile, coexisten dos especies de ostreros: Haematopus palliatus pitanay (ostrero blanco y Haematopus ater (ostrero negro. Ambas especies depredan en un sistema rocoso intermareal peculiar cuya franja media se encuentra dominada por el tunicado Pyura praeputialis (= Pyura stolonifera bradleyi; Kott 1997. En la literatura se discute sobre las diferencias morfológicas del pico (largo y ancho entre ambos tipos de ostreros. Dichas diferencias podrían segregar los roles de forrajeo de estas aves cuando comparten un mismo hábitat: los ostreros blancos atacarían preferentemente a presas de textura "blanda" y los ostreros negros atacarían presas de textura "dura" (i.e. cobertura calcárea. En este trabajo se consideró a P. praeputialis (piure de Antofagasta como una presa de textura "blanda", ya que su tunica, compuesta por tunicina, es suave y flexible. En el estudio se comparan diversos aspectos ecológicos entre ambas especies de ostrero tales como: (a abundancia de ostreros y de otras aves costeras que depredan sobre P. praeputialis, (b distribución espacial de los ostreros en el manto de piure durante sus actividades de depredación, (c tallas de piures preferidos, (d tiempos de manipulación, (e tasa de consumo y (f frecuencia de consumo de otros invertebrados distintos del piure. Los resultados señalan a H. palliatus pitanay como la especie de ostrero que ataca con mayor frecuencia a P. praeputialis. Por otra parte, H. ater ataca con mayor frecuencia presas de textura "dura" como: lapas, caracoles, choritos, erizosAt Antofagasta, northern Chile, two oystercatcher species coexist: the white oystercatcher, Haematopus palliatus pitanay and the black oystercatcher H. ater. Both species forage on an intertidal system where the middle fringe is dominated by the tunicate Pyura praeputialis (= Pyura stolonifera bradleyi; Kott 1997. According to the literature, differences in the morphology of their bills (length and width

  9. Glacier changes and climate trends derived from multiple sources in the data scarce Cordillera Vilcanota region, southern Peruvian Andes

    Directory of Open Access Journals (Sweden)

    N. Salzmann

    2013-01-01

    Full Text Available The role of glaciers as temporal water reservoirs is particularly pronounced in the (outer tropics because of the very distinct wet/dry seasons. Rapid glacier retreat caused by climatic changes is thus a major concern, and decision makers demand urgently for regional/local glacier evolution trends, ice mass estimates and runoff assessments. However, in remote mountain areas, spatial and temporal data coverage is typically very scarce and this is further complicated by a high spatial and temporal variability in regions with complex topography. Here, we present an approach on how to deal with these constraints. For the Cordillera Vilcanota (southern Peruvian Andes, which is the second largest glacierized cordillera in Peru (after the Cordillera Blanca and also comprises the Quelccaya Ice Cap, we assimilate a comprehensive multi-decadal collection of available glacier and climate data from multiple sources (satellite images, meteorological station data and climate reanalysis, and analyze them for respective changes in glacier area and volume and related trends in air temperature, precipitation and in a more general manner for specific humidity. While we found only marginal glacier changes between 1962 and 1985, there has been a massive ice loss since 1985 (about 30% of area and about 45% of volume. These high numbers corroborate studies from other glacierized cordilleras in Peru. The climate data show overall a moderate increase in air temperature, mostly weak and not significant trends for precipitation sums and probably cannot in full explain the observed substantial ice loss. Therefore, the likely increase of specific humidity in the upper troposphere, where the glaciers are located, is further discussed and we conclude that it played a major role in the observed massive ice loss of the Cordillera Vilcanota over the past decades.

  10. Air temperature, radiation budget and area changes of Quisoquipina glacier in the Cordillera Vilcanota (Peru)

    Science.gov (United States)

    Suarez, Wilson; Macedo, Nicolás; Montoya, Nilton; Arias, Sandro; Schauwecker, Simone; Huggel, Christian; Rohrer, Mario; Condom, Thomas

    2015-04-01

    The Peruvian Andes host about 71% of all tropical glaciers. Although several studies have focused on glaciers of the largest glaciered mountain range (Cordillera Blanca), other regions have received little attention to date. In 2011, a new program has been initiated with the aim of monitoring glaciers in the centre and south of Peru. The monitoring program is managed by the Servicio Nacional de Meteorología e Hidrología del Perú (SENAMHI) and it is a joint project together with the Universidad San Antonio Abad de Cusco (UNSAAC) and the Autoridad Nacional del Agua (ANA). In Southern Peru, the Quisoquipina glacier has been selected due to its representativeness for glaciers in the Cordillera Vilcanota considering area, length and orientation. The Cordillera Vilcanota is the second largest mountain range in Peru with a glaciated area of approximately 279 km2 in 2009. Melt water from glaciers in this region is partly used for hydropower in the dry season and for animal breeding during the entire year. Using Landsat 5 images, we could estimate that the area of Quisoquipina glacier has decreased by approximately 11% from 3.66 km2 in 1990 to 3.26 km2 in 2010. This strong decrease is comparable to observations of other tropical glaciers. In 2011, a meteorological station has been installed on the glacier at 5180 m asl., measuring air temperature, wind speed, relative humidity, net short and longwave radiation and atmospheric pressure. Here, we present a first analysis of air temperature and the radiation budget at the Quisoquipina glacier for the first three years of measurements. Additionally, we compare the results from Quisoquipina glacier to results obtained by the Institut de recherche pour le développement (IRD) for Zongo glacier (Bolivia) and Antizana glacier (Ecuador). For both, Quisoquipina and Zongo glacier, net shortwave radiation may be the most important energy source, thus indicating the important role of albedo in the energy balance of the glacier

  11. Anticuerpos contra Trichinella spiralis en la población rural de la provincia Cordillera, Bolivia

    Directory of Open Access Journals (Sweden)

    Alessandro Bartoloni

    1999-02-01

    Full Text Available Se realizó un estudio seroepidemiológico para determinar la prevalencia de anticuerpos contra Trichinella spiralis en el área rural de la provincia Cordillera del Departamento de Santa Cruz en Bolivia. Se examinaron 234 muestras de suero mediante el ensayo de inmunoabsorción enzimática (ELISA y se detectaron los anticuerpos en siete muestras (3%. Los resultados documentan por primera vez la presencia de infestación humana por Trichinella en Bolivia y sugieren la necesidad de fortalecer la vigilancia sanitaria de la triquinosis en los mataderos municipales, impedir la faena clandestina de animales y, sobre todo, lograr que los productores y pobladores tomen conciencia de los peligros de esta zoonosis.

  12. The unusual nature of recent snowpack declines in the North American cordillera.

    Science.gov (United States)

    Pederson, Gregory T; Gray, Stephen T; Woodhouse, Connie A; Betancourt, Julio L; Fagre, Daniel B; Littell, Jeremy S; Watson, Emma; Luckman, Brian H; Graumlich, Lisa J

    2011-07-15

    In western North America, snowpack has declined in recent decades, and further losses are projected through the 21st century. Here, we evaluate the uniqueness of recent declines using snowpack reconstructions from 66 tree-ring chronologies in key runoff-generating areas of the Colorado, Columbia, and Missouri River drainages. Over the past millennium, late 20th century snowpack reductions are almost unprecedented in magnitude across the northern Rocky Mountains and in their north-south synchrony across the cordillera. Both the snowpack declines and their synchrony result from unparalleled springtime warming that is due to positive reinforcement of the anthropogenic warming by decadal variability. The increasing role of warming on large-scale snowpack variability and trends foreshadows fundamental impacts on streamflow and water supplies across the western United States.

  13. Ethno-botanical survey of edible wild fruits in Benguet, Cordillera administrative region, the Philippines

    Science.gov (United States)

    Chua-Barcelo, Racquel Tan

    2014-01-01

    Objective To conduct a survey on the common name/s, traditional uses and cultural importance of the edible wild fruits in different municipalities of Benguet, Cordillera administrative region. Methods Interviews using questionnaires with barangay leaders and indigenous people were conducted with 176 key informants from June 2011 to July 2013. Results A total of 36 fruit species were found in different municipalities of Benguet. These fruit species belong to 27 genera and 20 families. Among the 13 municipalities of Benguet, Kibungan has the highest number of species. There are many uses of wild fruits which ranged from food (snack/dessert/table food), forage (especially for birds, monkeys and wild animals such as cloud rat and grass eaters), offertory, processed/preserved (as jam, jellies, candies, juice and wine), condiment or ingredient (for cooking), source of dye or ink, decoration (to garnish food) and as medicine to common ailments or health problems. Based on the inventory and calculated cultural importance index, Garcinia binucao (balokok) belonging to Clusiaceae is the most abundant fruit, hence it is the commonly used fruit for various purposes such as food, forage, processing/preservation and condiment/ingredient; Vaccinium myrtoides (ayusip) for offerings and as source of dye/ink; Saurauia elegans (uyok) for decoration, and, Antidesma bunius (bugnay) for medicine. Conclusions Benguet province in the Cordillera region provides a diversity of edible wild fruits. The data gathered from the study signifies that collection, processing and utilization of edible wild fruits are still part of the daily activities of the people in Benguet. PMID:25183144

  14. Measurements of light-absorbing particles on the glaciers in the Cordillera Blanca, Peru

    Science.gov (United States)

    Schmitt, C. G.; All, J. D.; Schwarz, J. P.; Arnott, W. P.; Cole, R. J.; Lapham, E.; Celestian, A.

    2015-02-01

    Glaciers in the tropical Andes have been rapidly losing mass since the 1970s. In addition to the documented increase in temperature, increases in light-absorbing particles deposited on glaciers could be contributing to the observed glacier loss. Here we report on measurements of light-absorbing particles sampled from glaciers during three surveys in the Cordillera Blanca Mountains in Peru. During three research expeditions in the dry seasons (May-August) of 2011, 2012 and 2013, 240 snow samples were collected from 15 mountain peaks over altitudes ranging from 4800 to nearly 6800 m. Several mountains were sampled each of the 3 years and some mountains were sampled multiple times during the same year. Collected snow samples were melted and filtered in the field then later analyzed using the Light Absorption Heating Method (LAHM), a new technique that measures the ability of particles on filters to absorb visible light. LAHM results have been calibrated using filters with known amounts of fullerene soot, a common industrial surrogate for black carbon (BC). As sample filters often contain dust in addition to BC, results are presented in terms of effective black carbon (eBC). During the 2013 survey, snow samples were collected and kept frozen for analysis with a Single Particle Soot Photometer (SP2). Calculated eBC mass from the LAHM analysis and the SP2 refractory black carbon (rBC) results were well correlated (r2 = 0.92). These results indicate that a substantial portion of the light-absorbing particles in the more polluted regions were likely BC. The 3 years of data show that glaciers in the Cordillera Blanca Mountains close to human population centers have substantially higher levels of eBC (as high as 70 ng g-1) than remote glaciers (as low as 2.0 ng g-1 eBC), indicating that population centers can influence local glaciers by sourcing BC.

  15. Measurements of light absorbing particulates on the glaciers in the Cordillera Blanca, Peru

    Science.gov (United States)

    Schmitt, C. G.; All, J. D.; Schwarz, J. P.; Arnott, W. P.; Cole, R. J.; Lapham, E.; Celestian, A.

    2014-10-01

    Glaciers in the tropical Andes have been rapidly losing mass since the 1970s. In addition to the documented increase in air temperature, increases in light absorbing particulates deposited on glaciers could be contributing to the observed glacier loss. Here we report on measurements of light absorbing particulates sampled from glaciers during three surveys in the Cordillera Blanca in Peru. During three research expeditions in the dry seasons (May-August) of 2011, 2012 and 2013, two hundred and forty snow samples were collected from fifteen mountain peaks over altitudes ranging from 4800 to nearly 6800 m. Several mountains were sampled each of the three expeditions and some mountains were sampled multiple times during the same expedition. Collected snow samples were melted and filtered in the field then later analyzed using the Light Absorption Heating Method (LAHM), a new technique that measures the ability of particulates on filters to absorb visible light. LAHM results have been calibrated using filters with known amounts of fullerene soot, a common industrial surrogate for black carbon (BC). As sample filters often contain dust in addition to BC, results are presented in terms of effective Black Carbon (eBC). During the 2013 survey, snow samples were collected and kept frozen for analysis with a Single Particle Soot Photometer (SP2). Calculated eBC mass from the filter analysis and the SP2 refractory Black Carbon (rBC) results were well correlated (r2 = 0.92). These results indicate that a substantial portion of the light absorbing particulates in the more polluted areas were likely BC. The three years of data show that glaciers in the Cordillera Blanca Mountains close to human population centers have substantially higher levels of eBC (as high as 70 ng g-1) than remote glaciers (as low as 2.0 ng g-1 eBC), indicating that population centers can influence local glaciers by sourcing BC.

  16. CO2-rich thermomineral groundwater in the Betic Cordilleras, southeastern Spain: Genesis and tectonic implications

    Science.gov (United States)

    Cerón, J. C.; Martín-Vallejo, M.; García-Rossell, L.

    The CO2-rich thermal groundwater in the Betic Cordilleras in Spain has been studied with regard to the geological and hydrogeological setting, physical and chemical characteristics, and 13C-isotope content. The study area is about 60km northeast of Almería city, in southeastern Spain. The thermomineral waters are plentiful and are related to regional geothermal anomalies. Temperatures of 20 -41°C, high bicarbonate concentrations (183-1824mg/L), and high amounts of PCO2 (aguas termales con elevados contenidos en CO2 de las Cordilleras Béticas han sido estudiadas en relación con los aspectos geológicos e hidrogeológicos, sus características físicas y químicas, y sus contenidos en 13C. El área de estudio se encuentra aproximadamente a 60km al noreste de la ciudad de Almería, en el sureste de España. Las aguas termominerales son numerosas y están relacionadas con anomalías geotermales regionales. El agua subterránea tiene una temperatura comprendida entre 20-41°C, alta concentración de bicarbonatos (entre 183-1824mg/L) y elevada PCO2 (agua subterránea origina problemas en los sondeos y en el uso del agua. El carácter hidrotermal de este área estaría relacionado con su actividad neotectónica.

  17. Market access and community size influence pastoral management of native and exotic livestock species: A case study in communities of the Cordillera Real in Bolivia's high Andean wetlands

    National Research Council Canada - National Science Library

    Quentin Struelens; Karina Gonzales Pomar; Susi Loza Herrera; Gaby Nina Huanca; Olivier Dangles; François Rebaudo

    2017-01-01

    Grazing areas management is of utmost importance in the Andean region. In the valleys of the Bolivian Cordillera Real near La Paz, pastoralism constitutes the traditional way for people to insure food security and economical sustainability...

  18. Tres nuevas especies del género Atelopus a.m.c. Dumeril & bibron 1841 (Amphibia: Bufonidae de las partes altas de la Cordillera Oriental Colombiana

    Directory of Open Access Journals (Sweden)

    Osorno Muñoz Mariela

    2001-12-01

    Full Text Available Se nominan y describen tres nuevas especies de Atelopus del grupo ignescens (sensu Lynch 1993 de las partes altas, en páramos y bosques nublados, de la Cordillera Oriental colombiana.Tree new species of the genus Atelopus ignescens (sensu Lynch 1993 group are named and described from the high altitudes ofthe cloud forest and paramos of the colombian Cordillera Oriental.

  19. Una nueva especie de Hyla del grupo Bogotensis (Amphibia: Anura: Hylidae de la Cordillera Oriental de Colombia Una nueva especie de Hyla del grupo Bogotensis (Amphibia: Anura: Hylidae de la Cordillera Oriental de Colombia

    Directory of Open Access Journals (Sweden)

    Ruíz Carranza Pedro M.

    1991-06-01

    Full Text Available A new species of Hyla is nomined from occidental slopes, northern Cordillera Oriental, Colombia; Hyla Iynchi differs from other hylid frogs of the H. bogotensis Group in having a rostral keel and a uniform black brown with a lavander dorsal color. Additional notes about systematics of hylid groups restricted to northern Andes, are given. Se nomina y describe una nueva especie de Hyla de la vertiente occidental, norte, de la Cordillera Oriental de Colombia. Hyla lynchi, es distinguible de todas las especies del Grupo H. bogotensis por su colorido dorsal café obscuro con tinte lavanda y la presencia de una carina medial en el extremo rostral. Se incluyen comentarios sobre la sistemática de grupos de Hyla restringidos al N de los Andes.

  20. Tipos de vegetación del llano de Paletará. Cordillera Central Colombia Tipos de vegetación del llano de Paletará. Cordillera Central Colombia

    OpenAIRE

    Restrepo Carla; Duque Andrés

    1992-01-01

    We studied the vegetation found in the Llano de Paletará, municipality of Coconuco, department of Cauca, Colombia. Based on the physiognomy and floristic composition of the vegetation we identified 8 paramo vegetation types. These units represent the most extensive azonal paramo vegetation types described up to now for the Cordillera Central. Four of the 8 vegetation types are herbaceous ("frailejonal-pajonal" with Espeletia, "chuscal abierto" with Chusquea,"swamp" with Carex, and "grassland"...

  1. Three new species of Pristimantis (Lissamphibia, Anura from montane forests of the Cordillera Yanachaga in Central Peru

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    William E. Duellman

    2007-12-01

    Full Text Available We describe three additional new species of Pristimantis from the Cordillera Yanachaga, a part of the Andes in central Peru. Analyses of DNA sequences of the mitochondrial rRNA genes show that onespecies is a close relative of P. bipunctatus (P. conspicillatus Group, another is a close relative of P. stictogaster (P. peruvianus Group, and the third is related to several species in the P. unistrigatus Group. The first two species are morphologically similar to their closest relatives but occur at lower elevations. Twenty-nine species of Pristimantis and Phrynopus are known from the vicinity of the Cordillera Yanachaga. The number of species, especially of Pristimantis, is high in the humid montane forestin comparison with other sites in humid montane forests in Peru, but the number is lower than on the western slopes of the Andes in Ecuador.

  2. Three new species of Pristimantis (Lissamphibia, Anura) from montane forests of the Cordillera Yanachaga in Central Peru

    OpenAIRE

    William E. Duellman; S. Blair Hedges

    2007-01-01

    We describe three additional new species of Pristimantis from the Cordillera Yanachaga, a part of the Andes in central Peru. Analyses of DNA sequences of the mitochondrial rRNA genes show that onespecies is a close relative of P. bipunctatus (P. conspicillatus Group), another is a close relative of P. stictogaster (P. peruvianus Group), and the third is related to several species in the P. unistrigatus Group. The first two species are morphologically similar to their closest relatives but occ...

  3. Metamorphic chlorite and "vermiculitic" phases in mafic dikes from the Maláguide Complex (Betic Cordillera, Spain)

    Czech Academy of Sciences Publication Activity Database

    Ruiz Cruz, M. D.; Novák, Jiří Karel

    2003-01-01

    Roč. 15, č. 1 (2003), s. 1-14 ISSN 0935-1221 Grant - others:Ministerio de Educación y Cultura(ES) BTE-2000-1150; Research Group(ES) RNM-199 Institutional research plan: CEZ:AV0Z3013912 Keywords : low-grade metamorphism * vermiculite * Betic Cordillera Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.185, year: 2003

  4. Variabilidad espacial de los atributos de la capa arable de un inceptisol del piedemonte de la cordillera oriental (casanare, colombia)

    OpenAIRE

    Peña Ricardo; Rubiano Yolanda; Peña Andrés; Chaves Bernardo

    2009-01-01

    El objetivo de este trabajo fue estudiar la variabilidad espacial de los atributos del suelo, enfocado a optimizar futuros muestreos en suelos similares. El estudio se realizó en una superficie de 58 ha, ubicada en Tauramena, departamento de Casanare, Orinoquia colombiana. El suelo del estudio corresponde a un Oxic Dystrudept de textura franco arenosa a franco arcillosa, localizado sobre un abanico de terraza del piedemonte de la cordillera Oriental. A través de...

  5. New insights on the crustal thickness and its lateral variations beneath the Rif Cordillera

    Science.gov (United States)

    Gil de la Iglesia, A.; Diaz Cusi, J.; Gallart, J.; Carbonell, R.; Harnafi, M.; Levander, A.

    2014-12-01

    The Rif cordillera forms, together with the Betic ranges, one of the tightest orogenic arcs on Earth. This continental boundary zone is dominated now by the slow convergence between Nubia and Eurasia, but with clear evidences of extensional tectonics. One of the missing elements to constrain the complex geodynamics of the Gibraltar Arc System is the knowledge on crustal structure beneath northern Morocco. In the last decade a major effort has been done in this sense, from active and passive seismics. We compile here the recent results available from the Rif domains. Two 330 km long wide angle DSS profiles were recorded end of 2011 across the Rif in NS and EW transects within the Rifsis project, complemented by onshore recordings of the Gassis-WestMed marine profiles. At the same period, BB seismic arrays were deployed in the area within Topo-Iberia and Picasso projects, allowing receiver function analyses of crustal depths. The ray-tracing modeling of the Rifsis profiles reveal a large Moho step and an area of crustal thickening both in EW and NS directions, grossly coincident with the Bouguer gravity anomalies. The deployment logistics allowed that all the stations recorded all the shots, thus providing useful offline data. We will use here all available in-line and offline data to provide a map of the crustal thickness in northern Morocco. We combined two approaches: i) a hyperbolic time reduction applied to the seismic data, resulting in low-fold stacks in which the reflections from the Moho should appear as subhorizontal lines; ii) the arrival times of the observed PmP phases allow, assuming a mean crustal velocity, to assign a midpoint crustal thickness to each lecture. Although some uncertainties may be inherent to those approaches, a large crustal root, reaching more than 50 km, is well documented in the central part of the Rif Cordillera, close to the zone where the Alboran slab may still be attached to the lithosphere. We also compared these results with

  6. Integrative computational tools for interpreting thermochronometric data: Application to the Colombian Eastern Cordillera

    Science.gov (United States)

    Ketcham, R. A.; Mora, A.; Almendral, A.; Parra, M.; Cassalas, W.; Robles, W.

    2011-12-01

    We present two new computational tools for interpreting thermochronometric data that facilitate the joint use of multiple samples to better constrain thermal history, and demonstrate their utilization in the Colombian Eastern Cordillera. The first, Fetmove, is a finite element solver that takes as input a series of detailed balanced cross sections, as created using a dedicated software package such as (2D)Move, and solves the heat flow equation in 2D along with predicted thermochronometric ages which can be compared against measured data. It is distinguished from similar tools in 2D and 3D principally by providing a level of detail that allows for investigation of samples in very specific and complex structural contexts, and a workflow that allows the interpreter to engage in successive refinements of the structural model using the inferences provided by thermochronometric data. The second tool is a new set of functionality in the HeFTy software for inverse modeling of thermochronometric data that allows for simultaneous modeling of samples down a well or borehole. This extension forces attention on issues that have previously been relatively neglected in such modeling, in particular that of multiple provenance. It is axiomatic that mineral grains in different strata may have come from different regions and have different inherited thermal histories. The same is frequently true for grains in single specimens, and is a frequent cause of apatite fission-track single-grain ages failing the chi-squared test. Interpreting such data in a realistic geological context thus requires allowing for different inherited populations within and between samples. The rewards in doing so include more robust modeling and interpretation and, in some cases, insights concerning the unroofing histories of the source rocks that contributed to a given sedimentary unit. Similarly, the mutual constraints imposed by modeling multiple samples with known or constrained depositional and

  7. New tools for integrative thermochronology, and their application to the Colombian Eastern Cordillera

    Science.gov (United States)

    Ketcham, R. A.; Mora, A.; Almendral, A.; Parra-Amezquita, M.; Casallas, W.; Robles, W.

    2013-12-01

    We present two new tools for interpreting thermochronometric data that facilitate the joint use of multiple samples to better constrain thermal history, and demonstrate their utilization in the Colombian Eastern Cordillera. The first, Fetkin, is a finite element solver that takes as input a series of detailed balanced cross sections created using dedicated software such as (2D)Move, and solves the heat flow equation in 2D along with predicted thermochronometric ages which can be compared against measured data. It also performs an independent analysis of the cross sections and flags aspects that are structurally out of balance. It is distinguished from similar tools in 2D and 3D principally by providing a level of detail that allows for investigation of samples in very specific and complex structural contexts, and a workflow that allows the interpreter to engage in successive refinements of the structural model using the inferences provided by thermochronometric data. The second tool is a new set of functionality in HeFTy for inverse modeling of thermochronometric data that allows for simultaneous modeling of samples down a well or borehole. This extension forces attention on issues that have previously been relatively neglected in such modeling, in particular that of multiple provenance. It is axiomatic that mineral grains in different strata may have come from different regions and have different inherited thermal histories. Interpreting such data in a realistic geological context thus requires allowing for different inherited populations within and between samples. The rewards in doing so include more robust modeling and interpretation and, in some cases, insights concerning the unroofing histories of the source rocks that contributed to a given sedimentary unit. Similarly, the mutual constraints imposed by modeling multiple samples with known or constrained depositional and structural context considerably amplifies the resolving power of thermochronometric data

  8. Andean deformation and rift inversion, eastern edge of Cordillera Oriental (Guateque Medina area), Colombia

    Science.gov (United States)

    Branquet, Y.; Cheilletz, A.; Cobbold, P. R.; Baby, P.; Laumonier, B.; Giuliani, G.

    2002-09-01

    In the Guateque-Medina area, Paleozoic basement and Mesozoic rift basins have been uplifted and exhumed during the Andean orogeny (12 Ma to present). Surface exposures and subsurface data constrain the deformation style and the rift geometry. We have mapped a regional transect and restored a cross section. We have also reconciled existing stratigraphic data, from cordillera, foothills and foreland basin, and have added new data of our own. In Early Cretaceous shales, there is evidence for fault-controlled sedimentation. A brecciated evaporitic layer, which is locally emerald bearing, has acted as a regional detachment. The underlying basement, composed of Paleozoic sediments, crops out as the Quetame Massif. It was uplifted during the Andean orogeny on a series of high-angle reverse faults. The main SE-verging Tesalia fault has resulted from Andean reactivation of an Early Cretaceous normal fault, which bounded a half-rift. A series of NW-verging back-thrusts may have resulted from Andean reactivation of Paleozoic faults. Between the back-thrusts and the Tesalia fault is a basement pop-up. It may be part of a flower structure, because components of right-lateral slip have been identified. These are attributed to eastward subduction of the Nazca plate beneath South America. In general, the style and timing of Andean deformation in the Guateque-Medina area are compatible with the plate tectonic setting of the northern Andes.

  9. ‘Diffuse faulting’ in the Machu Picchu granitoid pluton, Eastern Cordillera, Peru

    Science.gov (United States)

    Mazzoli, Stefano; Vitale, Stefano; Delmonaco, Giuseppe; Guerriero, Vincenzo; Margottini, Claudio; Spizzichino, Daniele

    2009-11-01

    A series of batholiths, forming part of the 'roots' of a Permo-Liassic rift system, are exposed in the high Eastern Cordillera of central Peru as a result of tectonic inversion. Shortening of the Machu Picchu granitoid pluton was accommodated by widespread shear reactivation of primary joints, by a process termed here 'diffuse faulting'. Fault-like reactivation of precursor joint surfaces, marked by chlorite, epidote and quartz shear fibres, is locally evidenced by few centimetres offsets within apparently undeformed granite. Analysis of fault slip data indicates that shear reactivation of different joint sets was kinematically consistent with ENE oriented shortening. Less frequent mylonitic shear zones appear to have evolved from the common brittle precursors. Apart from rare phyllonitic shear zones, fluid-rock interaction along the brittle precursors was generally limited, and pluton deformation appears to be mainly controlled by the geometry and distribution of primary joints. Three main sets of reactivated joints can be recognized, characterized by oblique-slip kinematics with variable reverse and strike-slip components of motion. Theoretical modelling based on quantitative fracture analysis (scan-line data) and different displacement-length relationships applied to the main reactivated joint sets yield first-order estimates of pluton finite strain. The results suggest that bulk finite strain is oblate and essentially coaxial, and is characterized by horizontal shortening not exceeding 10%. Relatively small finite strains, integrated over the size of the pluton, still result in a few kilometres of crustal shortening.

  10. Análisis de paleodietas humanas en zonas áridas a través de isótopos estables: el caso de Antofagasta de la Sierra (noroeste argentino

    Directory of Open Access Journals (Sweden)

    Violeta A. Killian Galván

    2016-01-01

    Full Text Available Este artículo presenta los primeros avances en la caracterización paleodietaria humana de individuos pertenecientes a la microrre - gión de Antofagasta de la Sierra, puna de Catamarca (noroeste argentino, correspon - dientes a diferentes periodos agropastoriles del Holoceno Tardío. Sobre un total de 14 in - dividuos se aplicó una metodología basada en el análisis de isótopos estables (δ 13 C colágeno y δ 15 N; δ 13 C apatita , considerando recursos loca - les y de áreas aledañas. Los resultados indi - can que el consumo de especies vegetales C 4 , como el maíz ( Zea mays y el amaranto ( Amaranthus caudatus , es menos importan - te respecto a otros recursos en la mayoría de los casos analizados, y son más relevantes los recursos cárnicos provenientes de las co - tas más bajas de la ecorregión puna.

  11. Climate dynamics along the arid northern coast of Chile: The 1997-1998 Dinámica del Clima de la Región de Antofagasta (DICLIMA) experiment

    Science.gov (United States)

    Rutllant, José A.; Fuenzalida, Humberto; Aceituno, Patricio

    2003-09-01

    The DICLIMA field experiment was designed to test and quantify the hypothesis of an afternoon enhancement of the coastal subsidence in the extremely arid northern Chile because of solar heating over the west slope of the Andes. Ten-day campaigns near Antofagasta (23°S) were carried out in January 1997, July 1997, and January 1998. Significant diurnal cycles in temperature, mixing ratio, and wind from about 1000 to 4000 m above sea level were observed. This layer was decoupled from the marine boundary layer circulation below by the subsidence inversion when its base was under the average height of the coastal mountain range. The solar heating cycle over the Andes and associated circulation resulted in a mean afternoon zonal divergence above the subsidence inversion base of about 30 × 10-6 s-1, exceeding by a factor of 5 typical subtropical west coast divergences. The corresponding early morning convergence was particularly intense during the austral winter experiment. In spite of the very strong El Niño conditions that prevailed during the July 1997 and January 1998 experiments, the overwhelming control that radiation exerts on the daily cycles of the atmospheric circulation over the west slope of the Andes seems to guarantee the general validity of the results.

  12. Mesoscale primary production and bio-optical variability off Antofagasta (23-24º S during the transition to El Niño 1997-1998 Variabilidad de la producción primaria y bio-óptica a mesoescala frente a las costas de Antofagasta (23-24º S durante la transición a El Niño 1997-1998

    Directory of Open Access Journals (Sweden)

    GEMITA PIZARRO

    2002-03-01

    Full Text Available The spatial variability of primary production (PP, chlorophyll-a (Chl-a and the photosynthetic parameters were studied off Antofagasta, Chile (23-24ºS, 70-72º W during austral summer and winter. Between cruises (January and July 1997, significant changes occurred in the water column, including higher temperatures in the euphotic zone (Zeu deepening of thermocline below Zeu, an increase of oxygen concentration and the intrusion of Subtropical Waters with potential limitation of nutrients. These strong physical anomalies due to the transition period of El Niño 1997-1998 appeared in this study area during March 1997. During the July cruise, the El Niño event 1997-1998 was in the middle of its development (IOS-2. The hypothesis that chlorophyll-a concentrations and primary production differ significantly in the coastal areas in the Antofagasta region due to year-round coastal upwelling was tested in this study. Photosynthesis versus irradiance (P-E experiments were performed daily, using simulated in situ incubations with samples collected within the Zeu. Also in vitro incubations were done at several selected stations. For results analyses, stations were pooled in coastal and oceanic sites according to distance from the narrow shelf and differential influence of local upwelling. Integrated Chl-a values during both cruises were significantly higher at the coastal stations, and since between cruises no differences were found, a mean value of 44 mg Chl-a m-2 can be reported for the coastal area. Daily PP values were significantly different in space and time (P Durante el verano e invierno austral, se estudió la variabilidad espacial de la producción primaria (PP, clorofila-a (Cl-a y los parámetros fotosintéticos en las costas de Antofagasta, Chile (23-24º S, 70-72º O. Entre ambos cruceros (enero y julio 1997 hubo cambios significativos en la columna de agua, los que incluyeron aumento de la temperatura en la zona eufótica (Zeu, profundizaci

  13. Structure of Sierra Blanca (Alpujarride Complex, west of the Betic Cordillera

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    Andreo, B.

    1995-04-01

    Full Text Available Sierra Blanca, situated in the SW of Málaga, forms part of the Blanca unit, belonging to the Alpujarride Complex of the Betic Cordillera. Its lithologic sequences are made up of a group of migmatites, gneisses and schists and an upper formation of marbles (white dolomitic and the bottom and blue calcareous towards the top, linked with a transitional contact. The structure of Sierra Blanca is comprised of folds, generally isoclinal, with reversed limbs and with important tectonic transpositions, the direction of which is approximately E-W in the eastern area and N-S and E-W in the West. In both areas the folds present opposing vergences, consistently towards the interior of the sierra. The origin of these structures is explained with a model of westerly movements of the Blanca unit, in relation to the Los Reales unit, with the formation of frontal and lateral folds. In its advancement, the western part of Sierra Blanca underwent an important anti-clockwise rotation responsible for the co-existence of folds in N-S and E-W directions. These structures occurred under ductile conditions, owing to the presence of important overthrusting peridotitic masses of the Los Reales unit. This model of westerly displacement is inserted in the process undergone by the Betic-Rif Internal Zones (with Blanca and Los Reales units included which occurred at the end of the Oligocene-Early Miocene when the Gibraltar arch began to be formed.Sierra Blanca, situada al SW de Málaga, forma parte de la unidad de Blanca que pertenece al complejo Alpujárride de la Cordillera Bética. Su secuencia litológica está compuesta por un conjunto inferior de migmatitas, gneises y esquistos, y por una formación superior de mármoles, blancos dolomíticos en la base y mármoles calizos azules hacia la parte superior, entre los que existe un tránsito gradual. La estructura de Sierra Blanca está formada por pliegues, generalmente isoclinales, con flancos invertidos que muestran

  14. Exhumation of the Western Cordillera of the Peruvian Andes (5-12°S)

    Science.gov (United States)

    Michalak, M.; Hall, S. R.; Farber, D.; Hourigan, J. K.

    2012-12-01

    The topography of mountain belts is the first-order morphological expression of the dynamical forces that drive plate tectonics. Despite recent advances in techniques that quantify tectonic and geomorphologic processes, characterizing the near and far-field forces that form mountainous topography at a continental scale remains challenging. The South American Andes are an example of a long-lived orogen that is morphologically and tectonically segmented. For example, the Northern Peruvian Andes are a region characterized by flat-slab subduction, no active volcanism and a relatively narrow section of high topography, in contrast to the central Andes, which contain the broad Altiplano-Puna plateau, active volcanism and normal-angle subduction. Current models of Andean orogenesis based on paleoelevation estimates, thermochronology data, and structural analysis suggest that most of the high topography evolved sometime in the last 20Ma, possibly characterized by a period of punctuated uplift from 10-6Ma. However, as many of these data are from the central Andes, they may not be directly applicable to the entire Andean chain. Therefore, it is critical to investigate areas outside of the central Andean region using similar techniques to test the applicability of these models elsewhere in the Andes. For this study, we use (U-Th)/He low-temperature thermochronology to characterize the shallow crustal cooling history from three sites in the Western Cordillera of the Peruvian Andes, across seven degrees of latitude (5°S to 12°S). Near-vertical sample transects were taken in three river valleys that expose the Jurassic through Eocene granitoids of the 1,600km long Coastal Batholith of Peru. By using both apatite and zircon (U-Th)/He thermochronometers we are able to quantify crustal exhumation rates as well as detect temporal and spatial accelerations and decelerations of exhumation. This new dataset, combined with existing crystallization ages of the plutonic sequence of the

  15. Slope deformations in high-mountain regions as observed by InSAR: Examples from the Cordillera Blanca, Peru

    Science.gov (United States)

    Frey, Holger; Strozzi, Tazio; Caduff, Rafael; Huggel, Christian; Klimeš, Jan; Vilímek, Vít; Wiesmann, Andreas; Kääb, Andreas; Cochachin, Alejo; Plummer, Stephen

    2016-04-01

    Steep topography, the world's highest concentration of tropical glaciers, numerous glacial lakes and strong seismic activity combined with a densely populated valley bottom in the Rio Santa basin characterize the Cordillera Blanca in Peru. Besides glacier-related processes, a variety of landslide types and processes is present outside the glaciated areas, favoured by the steep terrain, geological conditions, sparse vegetation, intense precipitation, and strong seismicity. This combination of high hazard potentials and vulnerabilities results in a long list of natural disasters. Information on surface displacements is very valuable for early detection of emerging hazard potentials and their assessment. Interferometric processing of SAR data (InSAR) provides the possibility to remotely detect different types of surface displacement processes, also in remote locations where no other monitoring data are available. This contribution, developed under the ESA-funded S:GLA:MO project (sglamo.gamma-rs.ch), shows the potential of InSAR products for hazard assessments and glaciological investigations in high-mountain regions. We present a selection of different surface displacements as observed in the Cordillera Blanca based on InSAR data: a landslide zone near the Rampac Grande village, where in 2009 a landslide caused casualties and property loss; a landslide at the entry of the Santa Cruz Valley, northern Cordillera Blanca, where the displacement history could be reconstructed over five years; surface displacements at the interior moraine slopes surrounding Laguna Palcacocha, a major glacier lake above the city of Huaraz, which are compared to and complemented by geophysical investigations in the field; surface displacements at the moraine damming Laguna Safuna Alta, a glacier lake in the northern part of the Cordillera Blanca; glacier velocities across the entire Cordillera Blanca, revealing ice flow velocities of more than 200 m yr-1 at certain locations at the end of

  16. Paleontologic and stratigraphic relations of phosphate beds in Upper Cretaceous rocks of the Cordillera Oriental, Colombia

    Science.gov (United States)

    Maughan, Edwin K.; Zambrano O., Francisco; Mojica G., Pedro; Abozaglo M., Jacob; Pachon P., Fernando; Duran R., Raul

    1979-01-01

    Phosphorite crops out in the Cordillera Oriental of the Colombian Andes in rocks of Late Cretaceous age as strata composed mostly of pelletal carbonate fluorapatite. One stratum of Santonian age near the base of the Galembo Member of the La Luna Formation crops out at many places in the Departments of Santander and Norte de Santander and may be of commercial grade. This stratum is more than one meter thick at several places near Lebrija and near Sardinata, farther south it is locally one meter thick or more near the base of the Guadalupe Formation in the Department of Boyaca. Other phosphorite beds are found at higher stratigraphic levels in the Galembo Member and the Guadalupe Formation, and at some places these may be commercial also. A stratigraphically lower phosphorite occurs below the Galembo Member in the Capacho Formation (Cenomanian age) in at least one area near the town of San Andres, Santander. A phosphorite or pebbly phosphate conglomerate derived from erosion of the Galembo Member forms the base of the Umir Shale and the equivalent Colon Shale at many places. Deposition of the apatite took place upon the continental shelf in marine water of presumed moderate depth between the Andean geosyncline and near-shore detrital deposits adjacent to the Guayana shield. Preliminary calculations indicate phosphorite reserves of approximately 315 million metric tons in 9 areas, determined from measurements of thickness, length of the outcrop, and by projecting the reserves to a maximum of 1,000 meters down the dip of the strata into the subsurface. Two mines were producing phosphate rock in 1969; one near Turmeque, Boyaca, and the other near Tesalia, Huila.

  17. Water Resources and Groundwater in a Glaciated Andean Watershed (Cordillera Blanca, Peru)

    Science.gov (United States)

    McKenzie, J. M.; Gordon, R.; Baraer, M.; Lautz, L.; Mark, B. G.; Wigmore, O.; Chavez, D.; Aubry-Wake, C.

    2014-12-01

    It is estimated that almost 400 million people live in watersheds where glaciers provide at least 10% of the runoff, yet many questions remain regarding the impact of climate change and glacier recession on water resources derived from these high mountain watersheds. We present research from the Cordillera Blanca, Peru, an area with the highest density of glaciers in the tropics. While glacier meltwater buffers stream discharge throughout the range, groundwater is a major component of dry season runoff, contributing up to 50-70% of outflow in some tributaries. In order to predict future changes to water resources it is critical to understand how groundwater can offset future hydrologic stress by maintaining stream baseflow, including recharge mechanisms, subsurface pathways, storage, and net fluxes to rivers. We present a synthesis of results based on hydrologic modeling, drilling/piezometers, geophysics, and artificial and natural hydrologic tracers. Our findings show that 'pampas', low-relief mountain valleys, are critical for baseflow generation by storing groundwater on interannual timescales. Pampas have a total area of ~65 km2 and are comprised of unconsolidated glacial, talus, lacustrine and wetland (bofedales) deposits. The valleys commonly have buried talus aquifers that are overlain by low permeability, glaciolacustrine deposits. Glaciofluvial outwash deposits and small wetlands also act as unconfined aquifers. These groundwater systems appear to be primarily recharged by wet season precipitation, and at higher elevations also by glacial meltwater. Additionally a ubiquitous feature in the valleys are springs, often located at the base of talus deposits, which generate a large hydrologic flux within the hydrologic systems. While glaciers are the most visible and vulnerable component of the Andean waterscape, we argue that it is crucial to understand the complete mountain hydrologic cycle, including groundwater, in order to understand the ongoing

  18. Stable isotope paleoaltimetry of Eocene core complexes in the North American Cordillera

    Science.gov (United States)

    Mulch, A.; Teyssier, C.; Cosca, M. A.; Chamberlain, C. P.

    2007-08-01

    The hydrogen isotope composition of Eocene muscovite in mylonitic quartzite from the Kettle and Shuswap metamorphic core complexes (Washington and British Columbia) permits estimates of paleoaltimetry of the North American Cordillera at the onset of post-collisional lithospheric extension. Coupled oxygen, hydrogen, and 40Ar/39Ar isotope data indicate that meteoric water penetrated to significant depths during normal faulting along the Columbia River Detachment bounding both Kettle and Shuswap metamorphic core complexes. Synkinematic muscovite attains δDmuscovite values as low as -135‰ and -157‰, respectively, consistent with δDwater values of -115 ± 5‰ and -135 ± 5‰. In context with stable isotope data from Eocene sedimentary basins of continental North America, these data constrain the isotopic composition of precipitation from which paleoelevation estimates can be made. Stable isotope paleoaltimetry indicates that during detachment formation (49-47 Ma), orogen-parallel variations in topography existed, and mean elevations decreased from ≥4000 m at the latitude of the Shuswap core complex to ≥3000 m in the Kettle core complex. In addition, these data indicate a net decrease in mean surface elevation by ˜1000 m since the Eocene. Our results for the Kettle core complex are consistent with paleoelevation estimates based on fossil floral physiognomy in the Eocene Republic basin (Washington), indicating that high elevations characterized not only the frontal escarpment near the crustal-scale detachment but continued into the Okanogan highlands further west. Collectively, the stable isotope, geochronological, and paleofloral data support tectonic models of high Eocene surface elevations contemporaneous with magmatism and lithospheric extension.

  19. Infrared Imaging and Modeling of Proglacial Stream Temperature in the Cordillera Blanca, Peru

    Science.gov (United States)

    Baker, E. A.; Lautz, L.; McKenzie, J. M.; Aubry-Wake, C.; Somers, L. D.; Wigmore, O.; Glose, A.; Glas, R. L.; Mark, B. G.

    2015-12-01

    In the tropical Andes, glacial meltwater is an important water resource for downstream communities, especially during the dry season. Due to climate change, glacial retreat is accelerating and straining already limited water resources in the region. It is hypothesized that groundwater storage and discharge will play a critical role in sustaining future river flows. To improve our understanding of the hydrologic fluxes in proglacial valleys of the tropical Andes, we monitored a ~1.2 km reach of the Quilcayhuanca River, in the Cordillera Blanca, Peru, using a high resolution infrared (IR) camera and in-stream temperature sensors. We positioned the IR camera on the southern valley wall, 96 m above the valley floor, and collected >700 IR images at 10 minute intervals over 5 days. We deployed 40 temperature sensors along the stream at ~25 m intervals and 10 sensors at additional control points throughout the surrounding valley, recording temperature at 10 minute intervals. Groundwater temperature was recorded in 6 wells in the study area. The reach had diurnal temperature fluctuations from ~4 to 13°C, but did not exhibit large longitudinal temperature differences. Stream temperature profiles within the water column show stream water is well mixed, improving the ability of the IR camera to accurately observe the stream temperature at this research site. Temperature sensors in 4 reach tributaries recorded warmer temperatures than the main channel. The daily temperatures of one tributary fluctuated within the range of the groundwater temperature (~9 to 11°C), while another tributary exhibited a range of ~18°C. A weather station in the study area recorded climate data (air temperature, humidity, wind speed, solar radiation) at 10 minute intervals. We used this field data as input for a spatial and temporal energy balance model of the reach. Our model demonstrates the utility of IR imagery to monitor stream temperatures and improves our understanding of energy fluxes in

  20. Sobre la compresión Neógena en la Cordillera Iberica

    Directory of Open Access Journals (Sweden)

    Paricio Cardona, J.

    1988-08-01

    Full Text Available We argue about micro and macrostructural data published in the paper in question supporting the hypothesis of some compressive regime being present in the Iberian Chain during the Miocene; at the same time, new data from other localities are presented. All these allow us to design a model of stress field characterized by a near N-S horizontal compression axis. After the LowerMiddle Miocene, E to ESE regional extension linked to the rifting of the eastern margin of the Iberian Peninsula is superposed. As a consequence, each point within the resulting stress field can register either compressive or extensive stress states at different times.En este artículo se hacen algunas precisiones acerca de los datos micro y macroestructurales que se aportaron en el trabajo citado en apoyo de la idea de un régimen compresivo vigente durante al menos una parte del Mioceno en la Cordillera Ibérica, al tiempo que se ofrecen datos nuevos procedentes de otras localidades. Todos ellos permiten diseñar un modelo de campo de esfuerzos caracterizado por una dirección de comprensión horizontal próxima a N-S, al que se superpone, a partir del Mioceno inferior-medio, una distensión E a ESE relacionada con el rifting del margen mediterráneo de la Península. La suma de ambos campos puede manifestarse, en cada momento y en cada lugar, por estados de esfuerzo tanto comprensivos como extensivos.

  1. Groundwater origin and recharge in the hyperarid Cordillera de la Costa, Atacama Desert, northern Chile.

    Science.gov (United States)

    Herrera, Christian; Gamboa, Carolina; Custodio, Emilio; Jordan, Teresa; Godfrey, Linda; Jódar, Jorge; Luque, José A; Vargas, Jimmy; Sáez, Alberto

    2018-05-15

    The Cordillera de la Costa is located along the coastline of northern Chile, in the hyperarid Atacama Desert area. Chemical and isotopic analyses of several small coastal springs and groundwater reservoirs between 22.5 °S and 25.5 °S allow understanding groundwater origin, renewal time and the probable timing of recharge. The aquifers are mostly in old volcanic rocks and alluvial deposits. All spring waters are brackish, of the sodium chloride type due to intensive concentration of precipitation due aridity and for deep groundwater to additional water-rock interaction in slowly renewed groundwater and mixing with deep seated brines. The heavy δ 18 O and δ 2 H values in spring water are explained by recharge by the arrival of moist air masses from the Pacific Ocean and the originally lighter values in the deep wells can be associated to past recharge by air masses coming from the Atlantic Ocean. Current recharge is assumed almost nil but it was significant in past wetter-than-present periods, increasing groundwater reserves, which are not yet exhausted. To explain the observed chloride content and radiocarbon ( 14 C) activity, a well-mixed (exponential) flow model has been considered for aquifer recharge. The average residence time of groundwater feeding the springs has been estimated between 1 and 2kyr, up to 5kyr and between 7 and 13kyr for deep well water, assuming that current recharge is much less than during the previous wetter period. The recharge period feeding the coastal springs could have been produced 1 to 5kyr BP, when the area was already inhabited, and recharge in the Michilla mine was produced during the 10 to 14.5kyr BP CAPE (Central Andean Pluvial Event) pluvial events of the central Andes. The approximate coincidence of turnover time with the past wet periods, as revealed by paleoclimate data, points to significant recharge during them. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. The role of inherited rifted lithospheric structure on middle Cretaceous orogeny and Tertiary-present extension, North American Cordillera

    Science.gov (United States)

    Tikoff, Basil; Kelso, Paul; Fayon, Annia; Gaschnig, Richard; Vervoort, Jeff; Stetson-Lee, Tor; Byerly, Ad

    2017-04-01

    While the Eastern North American margin exhibits evidence of the rifted margin on subsequent deformation, this record is more obscure along the western Cordilleran margin. We recently conducted paleomagnetic and geochronologic analyses along the abrupt, boundary between cratonic North American and accreted terranes in Idaho. In this location, the abrupt boundary is designated by geochemical gradients (Sr, Nd, O) that are spatially coincident with major, regional-scale (western Idaho, Ahsahka) shear zones. The boundary is oriented NS in central-southern Idaho, and then abruptly changes 90° near Orofino, ID, to become EW oriented. Recent paleomagnetic data indicates that 30° clockwise rotation of the entire margin occurred post 85 Ma. Reconstruction of this rotation orients the margins at 060 (transform) and 330 (extensional), parallel to the inferred orientation of the Precambrian rifted margin elsewhere in the US Cordillera. The geometry would cause a structural syntaxis during northward (right-lateral) translation of accreted terranes. Northward terrane motion at 100 Ma result in dextral transpressional kinematics along the 330-oriented western Idaho shear zone and contractional deformation in the EW-oriented Ahsahka shear zone (Cretaceous orientations) in this syntaxis. This middle Cretaceous orogeny occurs at the other major structural syntaxis, south of the Sierra Nevada batholith in southeastern California, as a result of a 100 Ma worldwide plate re-organization. The Idaho syntaxis also acts as a fulcrum for Tertiary-present rotation, explaining the current displacement field in the northern US Cordillera. Overall, the study indicates that the inherited Precambrian rifted margin of the North American Cordillera exhibited a significant influence on subsequent deformation, despite overprinting of abundant magmatism, margin parallel terrane translation, and subsequent rotation.

  3. Constraining Subsurface Structure and Composition Using Seismic Refraction Surveys of Proglacial Valleys in the Cordillera Blanca, Peru

    Science.gov (United States)

    Glas, R. L.; Lautz, L.; McKenzie, J. M.; Mark, B. G.; Baker, E. A.; Aubry-Wake, C.; Somers, L. D.; Wigmore, O.

    2015-12-01

    As tropical glaciers rapidly recede in response to climate change, the storage and discharge of groundwater will play an increasing role in regulating river baseflow, particularly during the dry season, when stream flow is currently sustained predominantly by glacial melt. Little is understood regarding the hydrogeologic processes controlling base flow characteristics of low-gradient proglacial valleys of the Cordillera Blanca in Northwestern Peru, which has the world's highest density of tropical glaciers. To better understand the processes of groundwater storage and discharge in proglacial meadows, we completed seismic refraction surveys in three representative valleys of the Cordillera Blanca range: the Quilcayhuanca, Yanamarey, and Pachacoto valleys. The locations of survey transects were chosen based on locations of previous sediment core sampling, GPR lines, and quantification of groundwater-surface water interaction derived from dye and temperature tracing experiments. The seismic surveys consisted of 48 vertical component geophones with 2.5 m spacing. Across the three representative valleys a total of 15 surveys were conducted, covering a distance of 1800 m in cross, down, and oblique-valley directions. Preliminary interpretation of the seismic refraction data indicates a maximum imaging depth of 16 m below land surface, and a transition from glacio-lacustrine sediments to buried saturated talus at a depth of 6 m in the Quilcayhuanca valley. The organic-rich glacio-lacustrine sediments in the Yanamarey valley have seismic velocities ranging from 300 to 800 m/s and are >16 m in thickness at mid- valley. Weathered metasedimentary bedrock in the Pachacoto valley was imaged at ~5 m below the valley surface, exhibiting a p-wave velocity of 3400 m/s. The knowledge of hydrogeologic structure derived from seismic refraction surveys will provide crucial boundary conditions for future groundwater models of the valleys of the Cordillera Blanca.

  4. Estratigrafía del Cretácico Superior de la Cordillera Oriental de la República Dominicana

    OpenAIRE

    García-Senz, J.; Monthel, J.; Díaz de Neira, J.A.; Hernaiz Huerta, P. P.; Calvo Sorando, José Pedro; Escuder Viruete, J.

    2007-01-01

    La sucesión del Cretácico Superior de la Cordillera Oriental de la República Dominicana contiene cerca de 6 km de rocas volcanogénicas sedimentarias y volcánicas depositadas en un sistema de talud sobre el extinto arco volcánico del Cretácico Inferior. Está limitada por dos discordancias que permiten caracterizarla como una secuencia deposicional. La inferior es consecuencia de los procesos de disgregación gravitacional que acompañan la formación del talud submarino; la superior se debe a la ...

  5. An enigmatic frog of the genus Atelopus (Family Bufonidae) from Parque Nacional Chirripó, Cordillera de Talamanca, Costa Rica.

    Science.gov (United States)

    Savage, Jay M; Bolaños, Federico

    2009-01-01

    A distinctive new species of Atelopus is described from Parque Nacional Chirrip6 Grande, Cordillera de Talamanca (3,400-3,500 m). It closely resembles populations of the Atelopus ignescens complex from the Andes of northern Ecuador and southern Colombia. It differs most significantly from these frogs in the pattern of spiculae and coni development on the throat, chest, hands and feet. The Costa Rican species appears to be an outlier of the complex inexplicably separated geographically from its nearest allies by an over land distance of about 1,600 km.

  6. Mapping Glacier Dynamics and Proglacial Wetlands with a Multispectral UAV at 5000m in the Cordillera Blanca, Peru

    Science.gov (United States)

    Wigmore, O.; Mark, B. G.

    2015-12-01

    The glaciers of the Cordillera Blanca, Peru are rapidly retreating as a result of rising temperatures, transforming the hydrology and impacting the socio-economic and environmental systems of the Rio Santa basin. Documenting the heterogeneous spatial patterns of these changes to understand processes of water storage and flow is hindered by technologic and logistic challenges. Highly complex topography, cloud cover and coarse spatial resolution limit the application of satellite data while airborne data collection remains costly and potentially dangerous. However, recent developments have made Unmanned Aerial Vehicle (UAV) technology a viable and potentially transformative method for studying glacier dynamics and proglacial hydrology. The extreme altitudes (4000-6700m) of the Cordillera Blanca limit the use of 'off the shelf' UAVs. Therefore we developed a low cost multispectral (visible, near-infrared and thermal infrared) multirotor UAV capable of conducting fully autonomous aerial surveys at elevations over 5000m within the glacial valleys of the Cordillera Blanca. Using this platform we have completed repeat aerial surveys (in 2014 and 2015) of the debris covered Llaca Glacier, generating highly accurate 10-20cm DEM's and 5cm orthomosaics using a structure from motion workflow. Analysis of these data reveals a highly dynamic system with some areas of the glacier losing as much as 16m of vertical elevation, while other areas have gained up to 5m of elevation over one year. The magnitude and direction of these changes appears to be associated with the presence of debris free ice faces and meltwater ponds. Additionally, we have mapped proglacial meadow and wetland systems. Thermal mosaics at 10-20cm resolution are providing novel insights into the hydrologic pathways of glacier meltwater including mapping the distribution of artesian springs that feed these wetland systems. The high spatial resolution of these UAV datasets facilitates a better understanding of the

  7. Análisis detallado del efecto foehn generado por la cordillera Oriental en el alto Magdalena (Huila y Tolima)

    OpenAIRE

    Armenta Porras, Guillermo Eduardo

    2013-01-01

    Se analiza la expresión del efecto foehn en la región que comprende el valle del alto Magdalena, la cordillera Oriental y el sector noroccidental del piedemonte Amazónico en el territorio colombiano. El análisis se hace utilizando datos mensuales registrados en estaciones meteorológicas localizadas en la región para el periodo 1971-2010, datos mensuales del reanálisis CFS (Climate Forecast System) para el periodo 1981-2010 y datos mensuales generados a partir del modelamiento numérico con WRF...

  8. Paleogeographic and tectonic controls on the evolution of Cenozoic basins in the Altiplano and Western Cordillera of southern Peru

    Science.gov (United States)

    Carlotto, Víctor

    2013-03-01

    Integrated studies of stratigraphy, sedimentology, paleogeography and tectonic controls on Cenozoic basins provide the basis for a series of time-slice reconstructions of basin evolution in the Andes of southern Peru. The Altiplano and adjacent margin of the Western Cordillera are characterized by several Paleocene-Miocene synorogenic continental basins with thicknesses locally exceeding 10 km. The evolution of these basins has been controlled by NW-trending tectonic features that mark the Altiplano-Western Cordillera and Altiplano-Eastern Cordillera boundaries and the Condoroma structural high. Sedimentary deposits of Paleocene age preserved in the Altiplano are the result of nonmarine sedimentation in a distal foreland basin. During the early Eocene, predominantly dextral strike-slip movements in the Altiplano between the Cusco-Lagunillas and Urcos-Ayaviri fault systems created the transpressional Kayra basin. The Soncco and Anta basins (middle Eocene-early Oligocene) are related to NE shortening (43-30 Ma) and represent proximal, wedge-top and foredeep basin environments preserved on the Altiplano. At ~ 29-28 Ma, a change to predominantly E-W shortening produced sinistral strike-slip motion along NW-striking faults, resulting in intermontane, transpressional basins. In the Altiplano, the Tinajani and Punacancha (29-5 Ma), and Paruro (12-6 Ma) basins were controlled by the Cusco-Lagunillas and the Urcos-Ayaviri fault systems. The Maure, Tincopalca-Huacochullo and Condoroma basins (22-5 Ma) of the Western Cordillera developed between the Condoroma high and the Cusco-Lagunillas fault system. Oligocene-Miocene sedimentation commonly evolved from proximal (alluvial) facies along the borders to distal (lacustrine) facies. These basins were linked to sinistral strike-slip faults that evolved into reverse-sinistral structures. Plate kinematics may play a role in Andean basin evolution, with deformation influenced by major preexisting faults that dictated paleogeographic

  9. Rare Moss-Built Microterraces in a High-Altitude, Acid Mine Drainage-Polluted Stream (Cordillera Negra, Peru)

    OpenAIRE

    Sevink, J.; Verstraten, J.M.; Kooijman, A.M.; Loayza-Muro, R.A.; Hoitinga, L.; Palomino, E.J.; Jansen, B.

    2015-01-01

    The Rio Santiago in the Cordillera Negra of Peru is severely contaminated by acid mine drainage in its headwaters. In a strongly acid stream, at about 3800?m above sea level (masl), microterraces were found with terrace walls built up of dead moss, with encrustations and interstitial fine, creamy sediment. The stream water was turbid due to the presence of similar suspended sediment, which also occurred as a thin basal layer in inter-rim basins. The moss was identified as the rare bryophyte A...

  10. Soil charcoal analysis as a climato-stratigraphical tool: The key case of Cordillera Real, northern Andes

    Energy Technology Data Exchange (ETDEWEB)

    Di Pasquale, G. [Dipartimento di Arboricoltura Botanica e Patologia Vegetale, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy); Impagliazzo, S., E-mail: stefania.impagliazzo@unina.i [Dipartimento di Arboricoltura Botanica e Patologia Vegetale, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy); Lubritto, C. [CIRCE, Dipartimento di Scienze Ambientali, II Universita di Napoli, and INNOVA, via Vivaldi, 43, 81100 Caserta (Italy); Marziano, M. [Dipartimento di Arboricoltura Botanica e Patologia Vegetale, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy); Passariello, I. [CIRCE, Dipartimento di Scienze Ambientali, II Universita di Napoli, and INNOVA, via Vivaldi, 43, 81100 Caserta (Italy); Ermolli, E. Russo [Dipartimento di Arboricoltura Botanica e Patologia Vegetale, Universita di Napoli Federico II, Via Universita 100, 80055 Portici (Italy)

    2010-04-15

    The present study represents the first attempt of reconstructing fire history through soil charcoal dating. The investigated area is located in the Guandera Biological Reserve (western Cordillera Real, northern Ecuador). Six AMS radiocarbon dating, performed at the base of five soil profiles allowed a fire phase to be identified during the Pleistocene-Holocene transition. A strong correspondence was highlighted between the age of the Guandera fires and the El Abra stadial, which is considered the Younger Dryas equivalent in South America. This local evidence of fires contributes to define the geographic area in which the El Abra stadial was recorded and suggests a wider use of the soil charcoal analysis.

  11. Reproductive and larval cycle of the scallop Argopecten purpuratus (Ostreoida: Pectinidae, during El Niño-La Niña events and normal weather conditions in Antofagasta, Chile

    Directory of Open Access Journals (Sweden)

    Miguel Avendaño

    2008-03-01

    Full Text Available Seasonality, amplitude, and magnitude of spawning events were determined for Argopecten purpuratus in the La Rinconada marine reserve, Antofagasta, Chile, between December 1995 and January 2004. During the same period, samples of scallop larvae were obtained in vertical plankton hauls recovered within this reserve in an area routinely exposed to circular, gyre-like currents which helped retain the larvae within the bay. The reproduction of this population in normal or cool (e.g. "La Niña", 1998-2000 years occurred throughout the year, with a more active period between September and April, declining in June and August; this contrasted with the warmer "El Niño" oceanographic period of 1997-98 in which reproductive activity was more intense and prolonged throughout the entire year. The reproductive events in this population were mostly synchronous, although one asynchronous period occurred each year following the more intense March to May spawnings. This reproductive activity generated a continuous presence of larvae in the area in which no strict relation could be found between the intensities of spawning and numbers of larvae in the water. Larval presence was, however, generally correlated with active spawning periods. Important increases in larval numbers recorded at the end of 1999 and the beginning of 2003 were correlated with census data showing a higher percentage presence of broodstock over 90 mm in shell length during these years. An adequate stock of this size class is needed for a successful seed capture program in the reserve (for mass culture. Rev. Biol. Trop. 56 (1: 121-132. Epub 2008 March 31.Entre 1995 y 2004 se determinó, con el índice gonadosomático, el ciclo reproductivo de Argopecten purpuratus en La Rinconada, Antofagasta, Chile. Paralelamente se realizaron muestreos larvales mediante arrastres verticales de plancton. La reproducción, en años normales y fríos (La Niña, 1998-2000, ocurre todo el año, con un período m

  12. A new species of semiarboreal toad of the Rhinella festae group (Anura, Bufonidae) from the Cordillera Azul National Park, Peru

    Science.gov (United States)

    Cusi, Juan C.; Moravec, Jiří; Lehr, Edgar; Gvoždík, Václav

    2017-01-01

    Abstract A new semiarboreal species of the Rhinella festae group is described from montane forests of the Cordillera Azul National Park between 1245 and 1280 m a.s.l. in the Cordillera Oriental, San Martín region, northern Peru. The new species is morphologically and genetically compared with members of the Rhinella acrolopha group (former genus Rhamphophryne) and members of the R. festae group. The new species is characterized by its large size (female SVL 47.1–58.3 mm, n = 4), eight presacral vertebrae, fusion of the sacrum and coccyx, long protuberant snout, snout directed slightly anteroventral in lateral view, cranial crests moderately developed, absence of occipital crest, presence of tympanic membrane, dorsolateral rows of small conical tubercles extending from parotoid gland to groin, hands and feet with long digits, fingers basally webbed and toes moderately webbed. Phylogenetically it is a member of the R. festae group which is most closely related to R. chavin and R. yanachaga from Peru. Morphologically the new species shares similarities with R. tenrec and R. truebae, members of the R. acrolopha group from Colombia. PMID:28769671

  13. An enigmatic frog of the genus Atelopus (Family Bufonidae from Parque Nacional Chirripó, Cordillera de Talamanca, Costa Rica

    Directory of Open Access Journals (Sweden)

    Jay M Savage

    2009-06-01

    Full Text Available A distinctive new species of Atelopus is described from Parque Nacional Chirripó Grande, Cordillera de Talamanca (3 400-3 500 m. It closely resembles populations of the Atelopus ignescens complex from the Andes of northern Ecuador and southern Colombia. it differs most significantly from these frogs in the pattern of spiculae and coni development on the throat, chest, hands and feet. The Costa Rican species appears to be an outlier of the complex inexplicably separated geographically from its nearest allies by an over land distance of about 1 600 km. Rev. Biol. Trop. 57 (1-2: 381-386. Epub 2009 June 30.Se describe una nueva especie de Atelopus del Parque Nacional Chirripó Grande, Cordillera de Talamanca (3 400-3 500 m sobre el nivel del mar. Se parece a poblaciones del complejo de Atelopus ignescens de los Andes del norte de Ecuador y del sur de Colombia. Principalmente difiere de estas ranas en el patrón de desarrollo de espículas y conos en la garganta, pecho, manos y pies. La especie de Costa Rica es atípica dentro del complejo por estar inexplicablemente separada geográficamente de sus más cercanos representantes por una distancia aproximada de 1 600 km por tierra.

  14. Late Cretaceous to Cenozoic deformation and exhumation of the Chilean Frontal Cordillera (28°-29°S), Central Andes

    Science.gov (United States)

    Martínez, Fernando; Parra, Mauricio; Arriagada, César; Mora, Andrés; Bascuñan, Sebastián; Peña, Matías

    2017-11-01

    The Frontal Cordillera in northern Chile is located over the flat-slab subduction segment of the Central Andes. This tectonic province is characterized by a thick-skinned structural style showing evidence of tectonic inversion and basement-involved compressive structures. Field data, U-Pb geochronological and apatite fission track data were used to unravel partially the tectonic history of the area. Previous U-Pb ages of synorogenic deposits exposed on the flanks of basement-core anticlines indicate that Andean deformation started probably during Late Cretaceous with the tectonic inversion of Triassic and Jurassic half-grabens. New U-Pb ages of the synorogenic Quebrada Seca Formation suggest that this deformation continued during Paleocene (66-60 Ma) with the reverse faulting of pre-rift basement blocks. The analysis of new apatite fission-track data shows that a rapid and coeval cooling related to exhumation of the pre-rift basement blocks occurred during Eocene times. This exhumation event is interpreted for first time in the Chilean Frontal Cordillera and it could have occurred simultaneously with the propagation of basement-involved structures. The age of this exhumation event coincides with the Incaic orogenic phase, which is interpreted as the most important to the Central Andes in terms of shortening, uplift and exhumation.

  15. Recent trends in annual snowline variations in the northern wet outer tropics: case studies from southern Cordillera Blanca, Peru

    Science.gov (United States)

    Veettil, Bijeesh Kozhikkodan; Wang, Shanshan; Bremer, Ulisses Franz; de Souza, Sergio Florêncio; Simões, Jefferson Cardia

    2017-07-01

    This paper describes the changes in the annual maximum snowlines of a selected set of mountain glaciers at the southern end of the Cordillera Blanca between 1984 and 2015 using satellite images. Furthermore, we analysed the existing glacier records in the Cordillera Blanca since the last glacial maximum to understand the evolution of glaciers in this region over a few centuries. There was a rise in the snowline altitude of glaciers in this region since the late 1990s with a few small glacier advances. Historical to the present El Niño-Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) records were also analysed to understand whether there was a teleconnection between the glacier fluctuations in the region and the phase changes of ENSO and PDO. We also assessed the variations in three important climatic parameters that influence the glacier retreat—temperature, precipitation, and relative humidity—over a few decades. We calculated the anomalies as well as the seasonal changes in these variables since the mid-twentieth century. There was an increase in temperature during this period, and the decrease in precipitation was not so prominent compared with the temperature rise. There was an exceptionally higher increase in relative humidity since the early 2000s, which is relatively higher than that expected due to the observed rate of warming, and this increase in humidity is believed to be the reason behind the unprecedented rise in the snowline altitudes since the beginning of the twenty-first century.

  16. Volcanism subprogram: Volcanological interpretation of the northern part of the Occidental Cordillera of Bolivia, utilizing ERTS imagery

    Science.gov (United States)

    Brockmann, C. E. (Principal Investigator); Kussmaul, S.

    1973-01-01

    The author has identified the following significant results. In the present study, 6 ERTS-1 images have been interpreted on a 1:1 million scale (black and white) with the respective field reconnaissance. The area studied is located in the region bordering with Chile and includes the western part of the Bolivian Altiplano, the volcano Cordillera (western cordillera) and the northern part of Chile to the Pacific Coast. The greater part of this region is formed by Pliocene/Pleistocene volcani rock, which is discordant with the Tertiary sediments with intercalations of calcareous tuff. The ERTS-1 imagery permits the tracing of regional boundaries of the great volcanic formations and the alinements of the volcanic bodies along the fault zones. They also permit a clear examination of the volcanic apparatus, including their secondary forms, such as lava flows, parasitic cones, and lava domes. Because of the great scale, it is not possible to identify either the small structures or those of low relief. On the basis of the interpretation of the images, it is possible to give an idea of the relative age of the volcanoes.

  17. The gold nuggets of the lower Pliocene Alhambra Formation (Betic Cordillera, Southern Spain)

    Science.gov (United States)

    Somma, Roberta; Bonvegna, Piero; Sanchez-Navas, Antonio

    2017-04-01

    The present research was devoted to the geochemical and textural characterization of gold nuggets extracted from auriferous siliciclastic deposits of the lower Pliocene continental Alhambra Formation (Betic Cordillera, Southern Spain). This Formation is mainly composed of metamorphic lithoclasts deriving both by the erosion of the Mulhacen Unit of the Nevado-Filabride Complex and the reworking of the upper Tortonian marine Dudar-Pinos Genil Formation, on its turn previously formed by erosion of the Veleta Unit of the Nevado-Filabride Complex. Particularly, the studied gold nuggets were separated from 1m3 of auriferous conglomerates sampled along the right side of the Genil River, in the abandoned Lancha de Cenes Mine, exploited since Roman time for gold mining. The recovered gold nuggets were 24 for a total weight of 0.125 g/m3. Textural analysis of gold nuggets was made by means mechanical sieving and visual comparison of roundness and form. They are sand-sized rounded to sub-rounded grains with spheroidal and cubic form. Surface analyses of the nuggets by SEM-EDS indicated that external portions show textures more porous than in the nuggets nuclei. Chemical analyses by EMPA indicated that they are constituted by pure gold with Ag and Hg as trace elements. The gold mine capacity of the studied auriferous deposits is at least of 0.125 g/m3 (lower than 0.5 g/m3; minimum value to be gold mine economically exploitable). Notwithstanding this value, the auriferous conglomerates of the Alhambra Formation reveal to be interesting under a gold mine exploitation point of view because of the gold high pureness degree. Finally, under a geological point of view, considering that the Alhambra Formation is mainly composed of lower Pliocene alluvial fan conglomerates and sandstones formed during the uplift of the Sierra Nevada, the selected gold nuggets are secondary deposits originally derived from primary deposits related to hydrothermal gold-bearing quartz veins included in

  18. Postglacial fluctuations of Cordillera Darwin glaciers (southernmost Patagonia) reconstructed from Almirantazgo fjord sediments

    Science.gov (United States)

    Bertrand, Sebastien; Lange, Carina B.; Pantoja, Silvio; Hughen, Konrad; Van Tornhout, Evi; Wellner, Julia Smith

    2017-12-01

    Most outlet glaciers of the Cordillera Darwin Icefield (CDI; Patagonia, 54°S) are currently transitioning from calving to land-based conditions. Whether this situation is unique to the modern climate or also occurred during the Holocene is entirely unknown. Here, we investigate the Holocene fluctuations of outlet glaciers from the northern flank of the CDI using a multi-proxy sedimentological and geochemical analysis of a 13.5 m long sediment core from Almirantazgo fjord. Our results demonstrate that sedimentation in Almirantazgo fjord started prior to 14,300 cal yr BP, with glacier-proximal deposits occurring until 13,500 cal yr BP. After 12,300 cal yr BP, most glaciers had retreated to land-locked locations and by 9800 cal yr BP, Almirantazgo fjord was a predominantly marine fjord environment with oceanographic conditions resembling the present-day setting. Our sediment record shows that during the first part of the Holocene, CDI glaciers were almost entirely land-based, with a possible re-advance at 7300-5700 cal yr BP. This is in clear contrast with the Neoglaciation, during which CDI glaciers rapidly re-advanced and shrank back several times, mostly in phase with the eastern outlet glaciers of the Southern Patagonian Icefield (SPI). Two significant meltwater events, indicative of rapid glacier retreat, were identified at 3250-2700 and 2000-1200 cal yr BP, based on an increase in grain-size mode and related inorganic geochemical parameters. This interpretation is additionally supported by concomitant decreases in organic carbon of marine origin and in Cl counts (salinity), reflecting higher terrestrial input to the fjord and freshening of the fjord waters. Overall, our record suggests that CDI outlet glaciers advanced in phase with eastern SPI glaciers during the Neoglaciation, and retreated far enough into their valleys twice to form large outwash plains. Our results also highlight the potential of fjord sediments to reconstruct glacier variability at high

  19. Timing and paleoclimatic significance of Holocene glacier fluctuations in the Cordillera Vilcabamba of southern Peru

    Science.gov (United States)

    Licciardi, J. M.; Taggart, J. R.; Schaefer, J. M.; Lund, D. C.

    2009-12-01

    Past fluctuations in climatically sensitive tropical glaciers provide important insight into regional paleoclimatic trends and forcings, but well-dated chronologies are scarce, particularly during the Holocene. We have established precise cosmogenic 10Be surface exposure ages of moraine sequences in the Cordillera Vilcabamba (13°20’S latitude), located in the outer tropics of southern Peru. Results indicate the dominance of two major glacial culminations and associated climatic shifts in the Vilcabamba, including an early Holocene glacial interval and a somewhat less extensive glaciation late in the ‘Little Ice Age’ (LIA) period. Lichenometric measurements on the youngest moraines support the 10Be ages, but uncertainties in the lichen ages arise from the lack of a local lichen growth curve. The Peruvian glacier chronologies differ from a recently-developed New Zealand record but are broadly correlative with well-dated glacial records in Europe, suggesting climate linkages between the tropics and the North Atlantic region. For the latest Holocene, our leading hypothesis is that climate forcings involving southward migration of the Atlantic Intertropical Convergence Zone can explain concurrent glaciations in tropical South America and northern high latitudes, but the influence of other climate drivers such as the El Niño/Southern Oscillation may have also played a role. Estimated differences between equilibrium-line altitudes (ELAs) on modern glaciers and those inferred for expanded latest Holocene glaciers reveal an ELA rise of 165-200 m since the LIA, suggesting that temperatures 1.1-1.3°C cooler than present could have sustained glaciers at their LIA maximum positions if temperature was the only control, and thus providing an upper bound on temperature depression during the LIA. However, further work is required to constrain the likely role of precipitation changes. These new Peruvian glacier chronologies and ELA reconstructions complement ice core and

  20. Retrograde metasomatic effects on phase assemblages in an interlayered blueschist-greenschist sequence (Coastal Cordillera, Chile)

    Science.gov (United States)

    Halama, Ralf; Konrad-Schmolke, Matthias

    2015-02-01

    Interlayered blueschists and greenschists of the Coastal Cordillera (Chile) are part of a Late Palaeozoic accretionary complex. They represent metavolcanic rocks with oceanic affinities based on predominantly OIB-type REE patterns and immobile trace element ratios. Both rock types have similar mineralogies, albeit with different mineral modal abundances. Amphibole is the major mafic mineral and varies compositionally from glaucophane to actinolite. The presence of glaucophane relicts as cores in zoned amphiboles in both blueschists and greenschists is evidence for a pervasive high-pressure metamorphic stage, indicating that tectonic juxtaposition is an unlikely explanation for the cm-dm scale interlayering. During exhumation, a retrograde greenschist-facies overprint stabilized chlorite + albite + winchitic/actinolitic amphibole + phengitic white mica ± epidote ± K-feldspar at 0.4 ± 0.1 GPa. Geochemical variability can be partly ascribed to primary magmatic and partly to secondary metasomatic processes that occurred under greenschist-facies conditions. Isocon diagrams of several adjacent blueschist-greenschist pairs with similar protolith geochemistry were used to evaluate metasomatic changes due to retrograde fluid-rock interaction. The most important geochemical changes are depletion of Si and Na and addition of water in the greenschists compared to the blueschists. Transition metals and LILE are mobilized to varying degrees. The unsystematic deviations from magmatic fractionation trends suggest open system conditions and influx of an external fluid. Pseudosection and water isopleth calculations show that the rocks were dehydrating during most of their exhumation history and remained at water-saturated conditions. The mineralogical changes, in particular breakdown of blue amphibole and replacement by chlorite, albite and calcic/sodic-calcic amphibole, are the prime cause for the distinct coloring. Pseudo-binary phase diagrams were used as a means to link bulk

  1. Pollen-based 17-kyr forest dynamics and climate change from the Western Cordillera of Colombia: no-analogue associations and temporarely lost biomes

    NARCIS (Netherlands)

    Velásquez-R., C.A.; Hooghiemstra, H.

    2013-01-01

    A 17 kyr long pollen record from the unexplored Western Cordillera of Colombia (Páramo de Frontino; 3460 m elevation) shows vegetation change and inferred climate dynamics at ~ 125 yr resolution. The cold and wet Lateglacial showed well-defined stadials and interstadials. At the transition to the

  2. Sea Surface Temperatures in the Eastern Equatorial Pacific and Surface Temperatures in the Eastern Cordillera of Colombia During El Niño: Implications for Pliocene Conditions

    Science.gov (United States)

    Pérez-Angel, Lina C.; Molnar, Peter

    2017-11-01

    Regressions of surface temperatures in the Eastern Cordillera of Colombia with sea surface temperatures (SSTs) in the equatorial Pacific, and specifically with Niño1+2 and Niño3 temperature anomalies, show that the Eastern Cordillera warms or cools by approximately half of the amplitude of the variation of SSTs in the eastern tropical Pacific. Because Pliocene SSTs in the eastern tropical Pacific resemble those during major El Niño events, when SSTs warm by 4°C, these regressions suggest that the Pliocene Eastern Cordillera was warmer by 2°C at both high and low elevations. Such post-Pliocene cooling is smaller than the 9-12°C inferred from fossil pollen assemblages, but comparable to recent estimates of Anderson et al. of 3 ± 1°C (1σ) since 8 Ma. This change in surface temperature could be explained by a change in regional climate associated with a different tropical Pacific SST distribution and therefore would require neither an elevation change of the Eastern Cordillera since that time nor a change between Pliocene and present-day temperatures in the tropics that is as large as estimates of the global change of 2.5-4°C.

  3. La vegetación azonal paramunade la Cordillera Oriental colombiana: síntesis fitosociológica preliminar

    Directory of Open Access Journals (Sweden)

    Rangel Churio Orlando

    2006-06-01

    Full Text Available El presente estudio aplica el uso de herramientas sistematizadas y los conceptos clásicos de la fitosociología en la identificación, caracterización y síntesis preliminar de las unidades de vegetación azonal presentes en la cordillera Oriental, revisando las propuestas anteriores de clasificación y analizando conjuntamente la información obtenida de 500 levantamientos realizados en la cordillera por numerosos investigadores entre 1976 y 2001 abarcando el área comprendida entre las regiones paramunas de Almorzadero al norte, Sumapaz al sur y occidente y la Sierra Nevada del Cocuy al oriente, distribuidos entre los límites con la vegetación de bosque altoandino (3.000 m hasta el superpáramo (4.435 m, incluyendo algunas localidades extrazonales (2.800 m. Se diferenciaron en total 136 unidades de vegetación distribuidas en seis clases, cinco órdenes, 17 alianzas, 61 asociaciones, 13  subasociaciones y 34 variantes, además, de 14  comunidades, agrupadas en cuatro tipos principales
    de vegetación: acuática y de ribera, cojines de pantano, herbácea de pantanos y turberas, y arbustiva de matorrales y chuscales. Los páramos del centro de la cordillera comparten la mayor riqueza de alianzas (diez,
    seguidos por los de la región Sur (nueve y los de Chingaza (ocho; la mayor riqueza de asociaciones se concentra en los páramos del sur y centro de la cordillera y en la región de la Sierra Nevada del Cocuy (25, 21 y 18 respectivamente. La vegetación de cinco alianzas presenta distribución restringida, tres de ellas existentes
    en la región de Tota, una en el centro de la cordillera y la restante en la región de Chingaza; el mayor número
    de asociaciones con distribución restringida se presenta en los páramos del Centro de la cordillera (diez, en la
    región de Tota (siete y en la región Sur (cinco. La vegetación de las alianzas Ditricho-Isoetion y Oreobolio-Plantagion posee amplia distribución a lo largo de

  4. Coupling data from U-series and 10Be CRN to evaluate soil steady-state in the Betic Cordillera

    Science.gov (United States)

    Schoonejans, Jerome; Vanacker, Veerle; Opfergelt, Sophie; Granet, Mathieu; Chabaux, François

    2015-04-01

    The regolith mantel is produced by weathering of bedrock through physical and biochemical processes. At the same time, the upper part of the regolith is eroded by gravity mass movements, water and wind erosion. Feedback's between production and erosion of soil material are important for soil development, and are essential to reach long-term steady-state in soil chemical and physical properties. Nowadays, long-term denudation rates of regolith can be quantified by using in-situ cosmogenic nuclides (CRN). If the soil thickness remains constant over sufficiently long time, soil production rates can be determined. However, the a priori assumption of long-term steady-state can be questionable in highly dynamic environments. In this study, we present analytical data from two independent isotopic techniques, in-situ cosmogenic nuclides and Uranium series disequilibrium. The disequilibrium of Uranium isotopes (238U, 234U, 230Th, 226Ra) is an alternative method that allows assessing soil formation rates through isotopic analysis of weathering products. Nine soil profiles were sampled in three different mountain ranges of the Betic Cordillera (SE Spain): Sierra Estancias, Filabres, Cabrera. All soils overly fractured mica schist and are very thin (roughly coincides with the pattern of long-term exhumation of the Betic Cordillera. Results from first simulations of the U-series disequilibrium model rather suggest that soil production rates are of the same order of magnitude in the Sierra Estancias and Cabrera. In the Sierra Filabres, the U-series disequilibrium in the depth profile do not respect the hypotheses of the model therefore no rates of soil production could be constrain for this profile. Thanks to the coupling of the two isotopic datasets the long term soil development will be explored in two profiles. This study highlights that comparison and combination of analytical techniques is useful to further unravel the mechanisms of chemical and physical weathering in such

  5. Tipos de vegetación del llano de Paletará. Cordillera Central Colombia Tipos de vegetación del llano de Paletará. Cordillera Central Colombia

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    Restrepo Carla

    1992-09-01

    Full Text Available We studied the vegetation found in the Llano de Paletará, municipality of Coconuco, department of Cauca, Colombia. Based on the physiognomy and floristic composition of the vegetation we identified 8 paramo vegetation types. These units represent the most extensive azonal paramo vegetation types described up to now for the Cordillera Central. Four of the 8 vegetation types are herbaceous ("frailejonal-pajonal" with Espeletia, "chuscal abierto" with Chusquea,"swamp" with Carex, and "grassland" with Calamagrostis , three are bush tickets (thicket with Hypericum, thicket with Ageratina, and thicket with Diplostephium, and one is a forest of low stature (forest with Escallonia. We analyze some aspects of the ecology and distribution of the vegetation types and evaluate their degree of peril and value of conservation. Se estudiaron los tipos de vegetación del Llano de Paletará, municipio de Coconuco, departamento del Cauca, Colombia. Basados en la fisonomía y composición florística de la vegetación identificamos 8 tipos de vegetación, los cuales representan los tipos de vegetación paramunos de carácter azonal más extensos de la Cordillera Central registrados hasta el momento. De los 8 tipos de vegetación, cuatro son de porte herbáceo (''frailejonalpajonal'' con Espeletia. "chuscal abierto" con Chusquea. "pantano" con Carex y un "pajonal" con Calamagrostis, tres son de porte arbustivo (matorral con Hypericum, matorral con Ageratina y matorral con Diplostephium y uno es de porte arbóreo (bosque con Escallonia. Se analizan algunos aspectos de la ecología y distribución de los tipos de vegetación y se evalúa su grado de amenaza y valor de conservación.

  6. Towards a GLOF hazard map for the city of Huaraz, Cordillera Blanca, Peru

    Science.gov (United States)

    Frey, Holger; Huggel, Christian; E Chisolm, Rachel; Gonzales, César; Cochachin, Alejo; Portocarrero, César

    2017-04-01

    Huaraz, with 120,000 inhabitants, is the largest city at the foot of the Cordillera Blanca Mountain Range, Peru, and is located at the confluence of the Quillcay River with the main Santa River. Three moraine dammed glacier lakes are located in the headwaters of the Quillcay catchment, which pose a potential threat of glacier lake outburst floods (GLOFs) to Huaraz: Laguna Cuchillacocha (2.5 x 106 m3), Laguna Tullparaju (12 x 106 m3), and Laguna Palcacocha (17 x 106 m3). The latter burst out in 1941, causing one of the deadliest GLOFs known in history, with about 2000 casualties and destroying a third of the city of Huaraz. Currently, the presence of these lakes within potential runout distances of possibly very large ice or rock/ice-avalanches, combined with the large damage potential in the city of Huaraz, some 20 km downstream of the lakes and further potentially endangered infrastructures such as the city of Trujillo, large-scale irrigation projects and hydropower plants along the Santa River poses a high-risk situation, despite lake safety systems at all three lakes were constructed in the last century. At Laguna Palcacocha, temporary measures, such as syphoning and a permanent supervision by a team of observers are undertaken at Laguna Palcacocha. For the future, more permanent measures are planned, including non-structural measures, such as a sensor-based early warning system for the entire catchment. In this framework, a preliminary GLOF hazard map for the entire Quillcay catchment has been developed, based on physically-based numerical modeling. For each of the three lakes, three scenarios of different magnitudes and related probabilities were modeled. For each case, a series of models was used to simulate each part of the chain of interacting processes. The eventual GLOFs were simulated with FLO2D for Palcacocha and RAMMS for Tullparaju and Cuchillacocha. Small, medium and large scenarios were merged for all three lakes, in order to come up with a single

  7. Metallogenesis and tectonics of the Russian Far East, Alaska, and the Canadian Cordillera

    Science.gov (United States)

    Nokleberg, Warren J.; Bundtzen, Thomas K.; Eremin, Roman A.; Ratkin, Vladimir V.; Dawson, Kenneth M.; Shpikerman, Vladimir I.; Goryachev, Nikolai A.; Byalobzhesky, Stanislav G.; Frolov, Yuri F.; Khanchuk, Alexander I.; Koch, Richard D.; Monger, James W.H.; Pozdeev, Anany I.; Rozenblum, Ilya S.; Rodionov, Sergey M.; Parfenov, Leonid M.; Scotese, Christopher R.; Sidorov, Anatoly A.

    2005-01-01

    The Proterozoic and Phanerozoic metallogenic and tectonic evolution of the Russian Far East, Alaska, and the Canadian Cordillera is recorded in the cratons, craton margins, and orogenic collages of the Circum-North Pacific mountain belts that separate the North Pacific from the eastern North Asian and western North American Cratons. The collages consist of tectonostratigraphic terranes and contained metallogenic belts, which are composed of fragments of igneous arcs, accretionary-wedge and subduction-zone complexes, passive continental margins, and cratons. The terranes are overlapped by continental-margin-arc and sedimentary-basin assemblages and contained metallogenic belts. The metallogenic and geologic history of terranes, overlap assemblages, cratons, and craton margins has been complicated by postaccretion dismemberment and translation during strike-slip faulting that occurred subparallel to continental margins. Seven processes overlapping in time were responsible for most of metallogenic and geologic complexities of the region (1) In the Early and Middle Proterozoic, marine sedimentary basins developed on major cratons and were the loci for ironstone (Superior Fe) deposits and sediment-hosted Cu deposits that occur along both the North Asia Craton and North American Craton Margin. (2) In the Late Proterozoic, Late Devonian, and Early Carboniferous, major periods of rifting occurred along the ancestral margins of present-day Northeast Asia and northwestern North America. The rifting resulted in fragmentation of each continent, and formation of cratonal and passive continental-margin terranes that eventually migrated and accreted to other sites along the evolving margins of the original or adjacent continents. The rifting also resulted in formation of various massive-sulfide metallogenic belts. (3) From about the late Paleozoic through the mid-Cretaceous, a succession of island arcs and contained igneous-arc-related metallogenic belts and tectonically paired

  8. The Meaning of High K2O Volcanism In the U.S. Cordillera

    Science.gov (United States)

    Putirka, K. D.; Busby, C.

    2010-12-01

    K2O contents provide a highly effective discriminant between volcanic rocks erupted in the Cascades and Basin-and Range-provinces, with Cascades volcanics having lower K2O contents at a given SiO2. To differentiate these suites, we use a K-index, where K-index = K2Oobserved - 0.12[SiO2] + 5.1 (oxides in wt. %). In the Sierra Nevada, regional K2O contents are not controlled by wall-rock assimilation. In addition, none are candidates for K-metasomatism, and none are likely to be derived by partial melting of a K-metasomatized source. As to the latter issue, even volcanic rocks with the highest K2O in the Sierra Nevada have K2O/Na2O 5, and as high as 30-40 (Brooks and Snee (1996). Also, Sierra-wide K2O variations are not connected to indices of subduction-related mantle enrichments (such as La/Nb, Ba/Nb or Sr/P2O5), and so K2O is unconnected to regional variations in source composition. K2O contents are instead controlled by the degree of partial melting (F) in the mantle source and fractional crystallization. Putirka and Busby (2007) show that maximum K2O in the Sierra increases with increasing crust thickness, and this relationship also holds across the U.S. the Cordillera (at 39oN latitude). This relationship implies that low F magmas more easily transit thick, low-density upper crust (Putirka and Busby, 2007), which is a consequence of the fact that low F melts are enriched not just in K2O, but also in H2O, which greatly lowers magma density (Ochs and Lange, 1999). This model can explain the contrast in Cascade and Basin-and-Range K2O contents: the modern Cascades are built on the thinner crust of accreted terranes, while typical Basin-and-Range volcanics are erupted on older, and thicker, cratonized crust. Mean crust density, however, cannot be the only explanation of high K2O. In the central Sierra Nevada, the Colorado River Extensional Corridor, and at the Lunar Crater/Nevada Test site area of NV, eruptions of high K2O magmas (K-index>1.65) coincide in time and

  9. Subduction and exhumation structures preserved in Cerro del Almirez HP metaserpentinites (Betic Cordillera, SE Spain)

    Science.gov (United States)

    Jabaloy-Sánchez, Antonio; López Sánchez-Vizcaíno, Vicente; Gómez-Pugnaire, María Teresa; Padrón-Navarta, José Alberto; Garrido, Carlos J.

    2014-05-01

    The Cerro del Almirez massif (Nevado-Filábride Complex, Betic Cordillera, SE Spain) is composed of antigorite serpentinite and chlorite harzburgite separated by a thin reaction front in a paleo-subduction setting. Structural analysis of ultramafic lithologies and metasedimentary host rocks provides information on the tectonic evolution of this massif during prograde metamorphism in a subduction zone and during subsequent exhumation. Here we report for the first time HP structures related to a subduction event underwent by ultramafic rocks of the Nevado-Filábride Complex. The oldest subduction-related structures are preserved in Atg-serpentinites: a penetrative S1 foliation and associated L1 stretching lineation were formed in a non-coaxial regime with a top-to-the-W sense of shearing. This planar linear fabric is crosscut by olivine ± Ti-clinohumite veins formed during the prograde breakdown of brucite and pre-metamorphic clinopyroxene at temperatures ranging from 465 to 500 ºC [1]. Veins occur as a system of decimetric long joints, some of them hybrid open and sheared veins with associated drag folds. They recorded embrittlement processes due to the release of 6% vol. H2O of the rock. S1 foliation can, however, be simultaneous with or be overgrown by olivine and/or tremolite porphyroblasts, product of the prograde reaction Di + Atg → Fo + Tr + H2O, which occurred at T > 600 ºC and P = 1.7-1.9 GPa [1]. Generation of S1/L1 fabric was followed by static annealing at ca. 680 ºC and 1.6-1.9 GPa [2]. The S1/L1 fabric in Atg-serpentinite is crosscut by the Atg-out isograd and overgrown by the Atg-serpentinite dehydration products that gave place to Chl-harzburgite. Peak metamorphic conditions of the Chl-harzburgite assemblage reached 680-710 ºC and 1.6-1.9 GPa [3]. Prograde Chl-harzburgite is crosscut by sets of conjugate zones associated to grain-size reduction of olivine grains [3]. These grain size reduction zones are interpreted as brittle structures

  10. Glacier Mass Balance in the Cordillera Vilcanota, Glacier Suyuparina, Cusco - Peru

    Science.gov (United States)

    Sikos, Felipe; Giráldez, Claudia; Schauwecker, Simone; Molina, Edwin; Haeberli, Wilfried; Drenkhan, Fabian; Salzmann, Nadine; Rado, Maxwell; Chaparro, Nicacio; Samata, Jaime; Flores, Andrés; Saito, Carlos; Montoya, Nilton

    2017-04-01

    The Cordillera Vilcanota is the second most glaciated mountain range in Peru, and concentrates approximately 279 km2 of ice extent which corresponds to 25% of Peruvian glaciers. These glaciers have shrunk about 33% within the last 40 years and are a direct indicator of climate change impacts. Hydroclimatic changes in this region pose hazards and consecutive risks for local and regional livelihoods, socioeconomic activities and water supply. Therefore, it is important to understand high-mountain climatic and hydroglacial parameters and dynamics. In 2010/11, the first mass balance measurements were made on the Suyuparina glacier and the adjacent Quisoquipina glacier. In 2013, we have continued measurements through the present, of which we present some of the results for Suyuparina glacier. The net point mass balance for the hydrological year 2013-2014 in the lower zone is highly variable with values between +0.2 m w.e. (accumulation) and up to -6 m w.e. (ablation).; whereas for the hydrological year 2014-2015 values range from +0.004 m w.e. (accumulation) to -0.047 m w.e. (ablation) depending on the particular microtopography (e.g. ice cliffs) of the glacier. In the accumulation zone, the average for two stakes was +1.4 m w.e. for the hydrological year 2012-2013 and 1.3 m w.e.,in 2013-2014, +1.2 m w.e. for 2014-2015; and +0.7 m w.e in 2015-2016, respectively. The water equivalent gain has been gradually reduced in the last estimate, depending exclusively on the rainfall regime. The velocity of the glacial flow from October 2013 to November 2014 is in the range of 10 to 20 m per year. The glacier retreat in the front corresponds to 48.49 m for the period 2010-2014. Total glacier area of Suyuparina has decreased by 7% from about 1.21 km2 in 2009 to 1.13 km2 in 2013. A seasonal pattern can be observed in the point mass balance, indicating less ablation in the wet season (December-May), continuous ablation in the dry period, and a high horizontal ablation due to its

  11. Tropical ocean-atmospheric forcing of Late Glacial and Holocene glacier fluctuations in the Cordillera Blanca, Peru

    Science.gov (United States)

    Stansell, Nathan D.; Licciardi, Joseph M.; Rodbell, Donald T.; Mark, Bryan G.

    2017-05-01

    Evaluating the timing and style of past glacier fluctuations in the tropical Andes is important for our scientific understanding of global environmental change. Terrestrial cosmogenic nuclide ages on moraine boulders combined with 14C-dated clastic sediment records from alpine lakes document glacial variability in the Cordillera Blanca of Peru during the last 16 ka. Late Glacial ice extents culminated at the start of the Antarctic Cold Reversal and began retracting prior to the Younger Dryas. Multiple moraine crests dating to the early Holocene mark brief readvances or stillstands that punctuated overall retreat of the Queshque Valley glacier terminus during this interval. Glaciers were less extensive during the middle Holocene before readvancing during the latest Holocene. These records suggest that tropical Atlantic and Pacific ocean-atmospheric processes exerted temporally variable forcing of Late Glacial and Holocene glacial changes in the Peruvian Andes.

  12. PIPER ANDAKIENSIS (PIPERACEAE UNA ESPECIE NUEVA DE LA VERTIENTE AMAZÓNICA DE LA CORDILLERA ORIENTAL DE COLOMBIA

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    WILLIAM TRUJILLO-C.

    2015-01-01

    Full Text Available Se describe e ilustra Piper andakiensis W. Trujillo & Callejas, sp. nov. (Piperaceae procedente del piedemonte oriental de la cordillera Oriental en la jurisdicción de los departamentos de Caquetá y Putumayo (SE de Colombia. La especie nueva se distingue por sus hojas basalmente lobadas y oblicuas sobre un lado, con lobos divergentes y más cortos que el pecíolo, la lámina foliar gruesa y cartácea, con tallos, haz de la hoja, pecíolos y pedúnculos glabros y con crecimientos epidérmicos en pecíolos y márgenes peciolares; se discuten sus relaciones taxonómicas, se presentan comentarios sobre su distribución y ecología y se ilustran sus caracteres diagnósticos.

  13. Variabilidad espacial de los atributos de la capa arable de un Inceptisol del piedemonte de la cordillera Oriental (Casanare, Colombia

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    Peña Ricardo

    2009-04-01

    Full Text Available

    El objetivo de este trabajo fue estudiar la variabilidad espacial de los atributos del suelo, enfocado a optimizar futuros muestreos en suelos similares. El estudio se realizó en una superficie de 58 ha, ubicada en Tauramena, departamento de Casanare, Orinoquia colombiana. El suelo del estudio corresponde a un Oxic Dystrudept de textura franco arenosa a franco arcillosa, localizado sobre un abanico de terraza del piedemonte de la cordillera Oriental. A través del análisis del semivariograma y de análisis de varianza anidado se encontr�� la distancia de muestreo óptima para cada variable analizada. Se halló que no hay diferencia entre las distancias óptimas encontradas bajo un método u otro cuando la varianza del atributo en cuestión tiene dependencia espacial.

  14. CARACTERIZACIÓN FÍSIOGRÁFICA DE LA PUNA DE SAJAMA, CORDILLERA OCCIDENTAL DE LOS ANDES (BOLIVIA

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    Fernando Javier Santa Cecilia Mateos

    2015-01-01

    Full Text Available Este artículo aproxima a la realidad física de la cordillera Occidental de los Andes. Un espacio geográfico donde los caracteres geológicos relacionados con el vulcanismo adquieren una relevancia especial en la configuración del paisaje andino. Los nevados y llanuras intermedias o altiplanos, son los dos elementos que constituyen la imagen de la puna andina, un territorio situado por encima de los 4.000 metros, ámbito intermedio entre los valles húmedos o yungas y las más altas cumbres de los Andes. A la singularidad volcánica habría que añadir la relacionada con el modelado glaciar, los aspectos hidrográficos y la biogeografia en esta área. El artículo toma como ejemplo de estudio la puna de Sajama en eldepartamento de Oruro, en la frontera boliviano-chilena.Abstract. This article approaches the physical reality of the Western Cordillera of the Andes. A geographical space where characters related geological volcanism are of particular importance in shaping the landscape Andean. The intermediate plains or mountains and plateaus, are the two elements that make up the image of the Andean puna, an area located above 4,000 meters, the middle ground between Yungas wet valley and the highest peaks of the Andes. A volcanic uniqueness should add that related to glacier modeling, hydrographic aspects and biogeography in this area. The article uses the example of the highlands of Sajama study in thedepartment of Oruro in Bolivian-Chilean border.

  15. Continental underthrusting and obduction during the Cretaceous closure of the Rocas Verdes rift basin, Cordillera Darwin, Patagonian Andes

    Science.gov (United States)

    Klepeis, Keith; Betka, Paul; Clarke, Geoffrey; Fanning, Mark; Hervé, Francisco; Rojas, Lisandro; Mpodozis, Constantino; Thomson, Stuart

    2010-06-01

    The Patagonian Andes record a period of Cretaceous-Neogene orogenesis that began with the compressional inversion of a Late Jurassic rift called the Rocas Verdes basin. Detrital zircon ages from sediment that filled the southern part of the basin provide a maximum depositional age of ˜148 Ma, suggesting that the basin opened approximately simultaneously along its length during the Late Jurassic. Structural data and U-Pb isotopic ages on zircon from granite plutons near the Beagle Channel (55°S) show that basin inversion involved two stages of shortening separated by tens of millions of years. An initial stage created a small (˜60 km wide) thrust wedge that placed the basaltic floor of the Rocas Verdes basin on top of adjacent continental crust prior to ˜86 Ma. Structures and metamorphic mineral assemblages preserved in an exhumed middle to lower crustal shear zone in Cordillera Darwin suggest that this obduction was accompanied by south directed subduction of the basaltic crust and underthrusting of continental crust to depths of ˜35 km beneath a coeval volcanic arc. A subsequent stage of out-of-sequence thrusting, culminating in the Paleogene, shortened basement and Upper Jurassic igneous rock in the internal part of the belt by at least ˜50 km, forming a bivergent thrust wedge. This latter period coincided with the exhumation of rocks in Cordillera Darwin and expansion of the fold-thrust belt into the Magallanes foreland basin. This orogen provides an important example of how orogenesis initiated and led to continental underthrusting and obduction of basaltic crust during closure of a quasi-oceanic rift basin.

  16. The Padul normal fault activity constrained by GPS data: Brittle extension orthogonal to folding in the central Betic Cordillera

    Science.gov (United States)

    Gil, Antonio J.; Galindo-Zaldívar, Jesús; Sanz de Galdeano, Carlos; Borque, Maria Jesús; Sánchez-Alzola, Alberto; Martinez-Martos, Manuel; Alfaro, Pedro

    2017-08-01

    The Padul Fault is located in the Central Betic Cordillera, formed in the framework of the NW-SE Eurasian-African plate convergence. In the Internal Zone, large E-W to NE-SW folds of western Sierra Nevada accommodated the greatest NW-SE shortening and uplift of the cordillera. However, GPS networks reveal a present-day dominant E-W to NE-SW extensional setting at surface. The Padul Fault is the most relevant and best exposed active normal fault that accommodates most of the NE-SW extension of the Central Betics. This WSW-wards dipping fault, formed by several segments of up to 7 km maximum length, favored the uplift of the Sierra Nevada footwall away from the Padul graben hanging wall. A non-permanent GPS network installed in 1999 constrains an average horizontal extensional rate of 0.5 mm/yr in N66°E direction. The fault length suggests that a (maximum) 6 magnitude earthquake may be expected, but the absence of instrumental or historical seismic events would indicate that fault activity occurs at least partially by creep. Striae on fault surfaces evidence normal-sinistral kinematics, suggesting that the Padul Fault may have been a main transfer fault of the westernmost end of the Sierra Nevada antiform. Nevertheless, GPS results evidence: (1) shortening in the Sierra Nevada antiform is in its latest stages, and (2) the present-day fault shows normal with minor oblique dextral displacements. The recent change in Padul fault kinematics will be related to the present-day dominance of the ENE-WSW regional extension versus NNW-SSE shortening that produced the uplift and northwestwards displacement of Sierra Nevada antiform. This region illustrates the importance of heterogeneous brittle extensional tectonics in the latest uplift stages of compressional orogens, as well as the interaction of folding during the development of faults at shallow crustal levels.

  17. From the Cordillera Blanca to the Pacific Ocean: hydrological changes and consequences across the Rio Santa watershed

    Science.gov (United States)

    Baraer, M.; Mark, B. G.; Wigmore, O.; Fernandez-Rivera, A.; McKenzie, J. M.; Walsh, E.

    2012-12-01

    The Rio Santa, Peru, drains the western slopes of the glacierized Cordillera Blanca and provides water resources for intense and diversified purposes. The Rio Santa basin sustains one of the most important hydropower plants in Peru, several middle-sized cities, high-elevation slope agriculture and mining industries. Glaciers in the Cordillera Blanca are rapidly retreating, modifying the hydrology of the upper Rio Santa watershed. Previous results show that the upper Rio Santa watershed has passed peak-water, the moment of maximum water availability, and now exhibit decreasing dry season discharge as a consequence of glacial retreat. We present results from data collected in July of 2011 and 2012, including discharge measurements using acoustic Doppler current profiling and major dissolved ion concentrations and stable isotopes of water. The hydrochemical data were analysed using the Hydrochemical Basin Characterization Method and the results are used to map the dry-season specific discharge variations across the entire Rio Santa watershed. Measurements from 2011 suggest that around 80% of current lower Rio Santa dry-season flows are diverted to supply water to major cities, intensive agriculture and hydro-electricity projects situated in the dry coastal area. Glacier retreat simulations are used to localize future hydrological changes and evaluate the downstream repercussions. Results show that glacierized catchments have higher specific discharge compared to non-glacierized catchments but the contribution of the glaciers during the dry season represent less than 30% of the Rio Santa discharge. As the glaciers further retreat, the Rio Santa dry-season outflows are going to progressively decrease to a level below the actual freshwater demand. These changes will adversely impact the socioeconomic vulnerability to water scarcity in the entire watershed while deepening the upstream/downstream disparity in water availability.

  18. La Cordillera de los Andes: presentación de los problemas geomorfológicos

    Directory of Open Access Journals (Sweden)

    1974-01-01

    érites sont souvent déblayées sur les pentes fortes par le ruissellement et les divers glissements et éboulements. El alzamiento en bóveda del Ponto-plioceno ha dado a los .Andes su volumen montañoso actual y ha llevado a más de 4000 m superficies de erosión elaboradas durante e! Terciario. Estas superficies o 'puna' son muy probablemente poligénicas y policíclicas. Están dominadas por grandes cordilleras que son generalmente horsts que delimitan los sectores de surrección máxima, horsts que son posteriores a la elaboración de la superficie de las mesetas. Esta superficie está deformada tanto sobre los bordes de las cuencas interiores como sobre los flancos de la montaña donde ella ha sido disectada y reducida a bandas. Algunas veces esta superficie ha podido desaparecer debido a su recorte en lo alto de los flancos de los grandes valles, sobretodo en los dos extremos de la cadena. A un nivel inferior, se desarrollaron aplanamientos menores durante el Plioceno y posiblemente durante el Cuaternario antiguo, en sectores que habían permanecido relativamente estables: son los 'glacis' de erosión en lazos del altiplano perú-boliviano o las superficies de abrasión retocadas en 'glacis' sobre los abombamientos costeros perú-chilenos. Algunos grandes valles están adaptados a las grandes direcciones estructurales consecutivas a los movimientos del fin de Terciario (la adaptación del conjunto va acompañada a menudo de numerosas inadaptaciones locales. Otros valles siguen antiguas direcciones estructurales, anteriores al alzamiento andino. El Cuaternario está marcado por una serie de períodos fríos acompañados de glaciaciones en la montaña. Se ha podido determinar lar existencia de cuatro glaciaciones distintas de las cuales una al menos remonta al Cuaternario antiguo. Las glaciaciones recientes son contemporáneas de las glaciaciones del Cuaternario reciente de Europa y de América del Norte. Sus causas hay que buscarlas, para las latitudes medias, en un

  19. Current deformation of the Betic Cordillera from a new GPS observation of the southern sector of the IBERIA95 Zero-Order Geodetic Network

    Science.gov (United States)

    Gil, Antonio J.; Galindo, Jesús; Alfaro, Pedro; de Lacy, María. Clara; Jesús Borque, María.; Franco, Juan A. Armenteros (1), Oscar; Ruano, Patricia; García Tortosa, Francisco Juan; López Garrido, Angel Carlos; Pedrera, Antonio

    2010-05-01

    The Betic Cordillera, located at the convergent plate boundary between Africa and Eurasia, is subjected to an average NNW-SSE compression and an associated orthogonal extension. In order to quantify this deformation a GPS campaign in the Southern Sector of IBERIA95 Zero-Order Geodetic Network was done in December 2008. This network was observed in 1995 by the Spanish National Geographical Institute (IGNE) and the Portuguese Institute of Cartography and Cadastre (IPCC) for the establishment of a Three-dimensional Geodetic Network in Spain and Portugal. The comparison of results in 1995 and 2009 provides one of the first geodetic results of the short-term deformation in the Betic Cordillera.

  20. Taxonomic revision of the moss salamander Nototriton barbouri (Schmidt (Caudata: Plethodontidae), with description of two new species from the Cordillera Nombre de Dios, Honduras.

    Science.gov (United States)

    Townsend, Josiah H

    2016-11-24

    Moss salamanders (genus Nototriton) are represented in northern Central America by nine putative species: N. barbouri, N. brodiei, N. lignicola, N. limnospectator, N. mime, N. picucha, N. saslaya, N. stuarti, and N. tomamorum. I estimate the phylogenetic relationships for these species based on data from three mitochondrial gene fragments (16S, cytochrome b, and COI), and compare morphological variation among putative taxa. As evidenced here and in previous studies, the taxon N. barbouri is paraphyletic with respect to populations from the Cordillera Nombre de Dios in northern Honduras. I restrict this taxon to populations from the Sierra de Sulaco in central Yoro, Honduras, and describe two new species from the Cordillera Nombre de Dios.

  1. Playas artificiales de Antofagasta. Un Proyecto Bicentenario

    Directory of Open Access Journals (Sweden)

    Gino Pérez Lancellotti

    2015-03-01

    Due to its rocky nature, the coast of the city lacks of natural beaches, so the local authorities in charge of urban development started in 2000 with the idea of providing the city with three large artificial beaches. In order to achieve this task, the project included the construction of coastal defenses and the filling of some parts with sand, with interesting environmental benefits.

  2. Two Tertiary metamorphic events recognized in metapelites of the Nevado-Filabride Complex (Betic Cordillera, S Spain)

    Science.gov (United States)

    Li, Botao; Massonne, Hans-Joachim

    2017-04-01

    The orogenic belt of the Betic Cordillera in southern Spain resulted from the collision of the African plate with the southwestern edge of the Eurasian plate in Alpine times. This belt can be considered as a large nappe stack with the Nevado-Filabride Complex in the eastern Betic Cordillera representing the lowest nappe, in which high-pressure (HP > 10 kbar) rocks such as eclogites occur. We have studied two metapelites from the Ragua (former Veleta) unit, which is the lowest unit of the Nevado-Filabride Complex. These rocks were sampled at Cerro de los Machos (sample 23085) and c. 3 km east of this locality at the Laguna de la Caldera (sample 23098) and contain quartz, potassic white-mica, paragonite, chlorite, garnet, biotite, tourmaline, epidote, rutile, ilmenite, apatite, zircon and monazite and titanite (23085) or calcite and albite (23098). Garnet in both rocks is similarly zoned. An inclusion-rich core shows a prograde metamorphic zonation with high and low Mn contents in the center (e.g. for 23085: Alm64.5Grs27Py2.5Sps6) and at the rim (Alm84Grs8Py6Sps2), respectively, of the core domain. After corrosion of this domain a garnet mantle formed with an inner zone being again relatively rich in Mn and an outermost rim being poor in Mn. This mantle is significantly richer in Mg and poorer in Ca compared to the core domain. Potassic white-mica in the samples also shows a considerable compositional spread (Si = 3.05-3.20 in 23085 and 3.13-3.33 in 23098) with the highest Si contents in the core of potassic white-mica grains. To elucidate the metamorphic evolution of the rocks we calculated various P-T pseudosections for different H2O-CO2 contents and Fe3+/Fe2+ ratios with PERPLE_X. On the basis of the compositions of the garnet inner core and the highest Si content in potassic white mica contrasting peak pressures at c. 535˚ C resulted for the rocks (23085: 12.8 kbar, 23098: 18.3 kbar). A subsequent pressure release to about 8 (23085) or 5 kbar (23098) at slightly

  3. ANÁLISIS MORFOLÓGICO DE LAS ESPORAS DE SERPOCAULON (POLYPODIACEAE DE LA CORDILLERA CENTRAL DE COLOMBIA

    Directory of Open Access Journals (Sweden)

    Ramírez-valencia Valentina

    2013-07-01

    Full Text Available Serpocaulon A. R. Sm. es un género monofilético de Polypodiaceae, compuesto por42 especies neotropicales, cuya mayor riqueza de especies se encuentra en Colombia,principalmente en la Cordillera Central (21 taxones. Su delimitación infragenéricaaún no es precisa, debido a: a problemas nomenclaturales, b el desconocimiento desu distribución geográfica, c su diversidad y d los múltiples eventos de hibridaciónpresentes en el género. Con el fin de incrementar el conocimiento taxonómico deSerpocaulon, se describió la morfología de las esporas de 21 taxones registrados enla Cordillera Central de Colombia, a partir de microscopía de luz transmitida-MLT yelectrónica de barrido-MEB. Los especímenes analizados fueron obtenidos de herbariosregionales. Se evaluaron 15 caracteres morfológicos y se promediaron 25 esporas envista lateral y 25 en vista proximal por taxón. Se realizó un análisis de componentesprincipales (ACP con el fin de identificar la variabilidad de los taxones. Se registraronesporas mónadas, heteropolares, con simetría bilateral, y formas elipsoidales, subelipsoidalesa globulares en vista proximal y plano-convexas a cóncavo-convexas envista lateral. Todos los taxones estudiados presentan ornamentación verrugada, quevaría en tamaño, forma y distribución. Se observaron dos tipos de perisporio (plegadoy liso. Los resultados sugieren que las verrugas son un importante carácter en ladeterminación de las especies, así como en su definición infragenérica, y que el ACPes útil para identificar algunos patrones morfológicos. Finalmente, se sugieren cuatrogrupos morfológicos conformados por especies que coinciden con clados propuestospreviamente en estudios moleculares.

  4. Crustal root beneath the Rif Cordillera as imaged from both active seismic data and teleseismic receiver functions.

    Science.gov (United States)

    Diaz, Jordi; Gil, Alba; Gallart, Josep; Carbonell, Ramon; Harnafi, Mimoun; Levander, Alan

    2015-04-01

    The Rif cordillera forms, together with the Betic ranges, one of the tightest orogenic arcs on Earth. This continental boundary zone is dominated now by the slow convergence between Nubia and Eurasia, but with clear evidences of extensional tectonics. One of the missing elements to constrain the complex geodynamics of the Gibraltar Arc System is the knowledge of the crustal architecture beneath northern Morocco. In the last decade a major effort has been done in this sense, from active and passive seismics. We compile here the recent results available from the Rif domains. Two 330 km long wide angle DSS profiles were recorded end of 2011 across the Rif in NS and EW transects within the Rifsis project, complemented by onshore recordings of the Gassis-WestMed marine profiles. At the same period, BB seismic arrays were deployed in the area within Topo-Iberia and Picasso projects, allowing receiver function analyses of crustal depths. The ray-tracing modeling of the Rifsis profiles reveal a large Moho step and an area of crustal thickening both in EW and NS directions, grossly coincident with the Bouguer gravity anomalies. The deployment logistics allowed that all the stations recorded all the shots, thus providing useful offline data. We will use here all available in-line and offline data to provide a map of the crustal thickness in northern Morocco. We combined two approaches: i) a hyperbolic time reduction applied to the seismic data, resulting in low-fold stacks in which the reflections from the Moho should appear as subhorizontal lines; ii) the arrival times of the observed PmP phases allow, assuming a mean crustal velocity, to assign a midpoint crustal thickness to each lecture. Although some uncertainties may be inherent to those approaches, a large crustal root, reaching more than 50 km, is well documented in the central part of the Rif Cordillera, close to the zone where the Alboran slab may still be attached to the lithosphere. We also compared these results

  5. The Cenozoic paleoelevation and paleogeographic history of the southwwestern US Cordillera: A combined sedimentologic and isotopic approach

    Science.gov (United States)

    Lechler, Alex R.

    The Cenozoic paleoelevation history of the Western US Cordillera has far-reaching implications for resolving the tectonic and geodynamic evolution of the region. The observed systematic relationship between elevation and the stable isotopic composition (delta-180 and delta-D) of surface meteoric waters provides an opportunity to construct quantitative paleoelevation histories using authigenic mineral proxies for the isotopic composition of paleo-meteoric waters, but uncertainties and complications inherent to this approach require further study. Part I of this dissertation critically evaluates the stable isotope paleoaltimetry technique through investigation of the dominant environmental controls on modern precipitation and surface water delta-180 distributions. This modem analysis reveals that isotope-elevation relationships vary systematically as a function of physiographic and climatic environment, with reduced delta-180-elevation gradients characterizing continental interior and orogenic plateau regions. This finding has important implications for future interpretations of paleometeoric water proxy records as the physiographic and climatic setting in which proxies formed must be taken into account in order for accurate paleoelevation determinations to be made. Part II of this dissertation builds on the findings and implications of Part I to provide new paleoelevation and paleogeographic constraints on the early Cenozoic western US Cordillera. Standard stable isotope paleoaltimetry techniques in conjunction with zircon U-Pb provenance study of early Cenozoic sedimentary basin systems in the southern Sierra Nevada region provides definitive evidence for near sea level paleoelevations in the southernmost Sierra Nevada ˜ 60 million years ago. This paleoelevation requires 1.5 -- 2 km of surface uplift since Eocene time, providing additional support for models proposing major Late Cenozoic uplift of the central and southern Sierra Nevada due to loss of dense, mantle

  6. The evolution of the Piedemonte Llanero petroleum system, Cordillera Oriental, Colombia: (1) Structural evolution and play definition

    Energy Technology Data Exchange (ETDEWEB)

    Graham, R.; Howe, S.; O`Leary, J. [BP Exploration, Bogota (Colombia)] [and others

    1996-08-01

    The Piedemonte Llanero petroleum trend of the Cordillera Oriental in Colombia has proven to be one of the most prolific hydrocarbon provinces discovered in recent years. The Piedemonte Llanero is a fold and thrust belt of complex, multi-phase structuration and hydrocarbon generation. Following the discovery of the Cusiana and Cupiagua fields in the southern part of the trend, BP and its partners began exploration further to the northeast. Early seismic data showed the existence of two structural trends: the frontal (or basal) thrust trend, with structures similar to Cusiana; and the overthrust (or duplex) trend, with multiple imbricated structures. Improved quality seismic data defined the gross structures and allowed them to be successfully drilled, but did not give a constrained model for the kinematic evolution of the fold and thrust belt nor the petroleum play. This resulted in no clear predictive models for reservoir quality and hydrocarbon phase distribution in the undrilled parts of the trend. A wide variety of geological and geochemical analytical techniques including biostratigraphy, reservoir petrology, petroleum geochemistry, thermal maturity data, basin modelling and fluid inclusion studies were undertaken. These were iteratively integrated into the seismo-structural model to develop a constrained interpretation for the evolution of the Piedemonte Llanero petroleum system. This paper summarizes the current understanding of the structural evolution of the trend and the development of a major petroleum system. A companion paper details the reservoir petrography and petroleum geochemistry studies.

  7. Late extensional shear zones and associated recumbent folds in the Alpujarride subduction complex, Betic Cordillera, southern Spain

    Energy Technology Data Exchange (ETDEWEB)

    Orozco, M.; Alonso-Chaves, F.; Platt, J.

    2017-11-01

    The existence in the Alpujarride Complex (Betic Cordillera, southern Spain) of a relatively continuous extensional event (following crustal thickening) is based on detailed structural studies and is consistent with the P-T paths and geochronological data established for the Alpujarride rocks. According to our research, the Alpujarride Complex contains two large-scale shear zones accommodating early Miocene extension. The shear zones contain km-scale recumbent folds, some with sheath fold geometry, and megaboudinage structures, and are closely associated with detachment faults. Large-scale folds and boudins cause dome-like undulations in the detachments, which are inferred to overlap in time with the deformation in the shear zones. One shear zone in the eastern part of the orogen is top-N; the other, in the western part, is top-E. The change in the shear direction may represent a temporal evolution in the direction of shear, possibly related to a change in the subduction direction in space and time.

  8. Rare Moss-Built Microterraces in a High-Altitude, Acid Mine Drainage-Polluted Stream (Cordillera Negra, Peru).

    Science.gov (United States)

    Sevink, Jan; Verstraten, Jacobus M; Kooijman, Annemieke M; Loayza-Muro, Raul A; Hoitinga, Leo; Palomino, Edwin J; Jansen, Boris

    The Rio Santiago in the Cordillera Negra of Peru is severely contaminated by acid mine drainage in its headwaters. In a strongly acid stream, at about 3800 m above sea level (masl), microterraces were found with terrace walls built up of dead moss, with encrustations and interstitial fine, creamy sediment. The stream water was turbid due to the presence of similar suspended sediment, which also occurred as a thin basal layer in inter-rim basins. The moss was identified as the rare bryophyte Anomobryum prostratum (Müll. Hal.) Besch. Chemical and mineralogical analyses show that green, living parts of the moss are gradually coated by Al/Fe (hydr)oxides, inducing their senescence and death. The necromass is covered by creamy crusts through precipitation of schwertmannite-type material from the stream water and simultaneous 'capture' of fine sediment. The latter consists of a mixture of precipitate and fine detrital primary minerals. These processes are held responsible for the formation of the microterraces, which regarding their composition and environment seem to be unique. Remarkable is the high As content of the creamy crusts and sediment, attributed to strong sorption of As, whereas its solute concentration is relatively low. This calls for more attention to suspended fine sediment in the assessment of environmental risks of stream water use. Lastly, the results raise serious doubts about the use of aquatic bryophytes as bioindicator for chemical pollution in acid mine drainage-polluted streams.

  9. La Icnofacies Zoophycos-Chondrites del Cretácico de la Cordillera Occidental de Colombia y su posible significación paleoambiental La Icnofacies Zoophycos-Chondrites del Cretácico de la Cordillera Occidental de Colombia y su posible significación paleoambiental

    Directory of Open Access Journals (Sweden)

    Etayo Serna Fernando

    1986-12-01

    Full Text Available The Zoophycos-Chondrites ichnofacies is common in fine-grained Cretaceous sedimentary rocks, in both biosiliceous and terrigenous claystone and siltstone of the Western Cordillera of Colombia, but it is absent from isopic coeval rocks of the Central and Eastern Cordilleras: The absence of this ichnofacies is attributed to the influence of a belt of oceanic anoxic waters developped during middle and late Cretaceous, that caused stagnant episodes in the sea floor of the epicontinental seas that stretched across the places of the actual Central and Eastern Cordilleras, but that did not affect the deep-sea floor where the sediments of the present Western Cordillera were accumulating.  In sections perpendicular to the bedding the trace fossil Zoophycos generally appears as belt-like burrows composed of a series of closely juxtaposed meniscate markings. Identification in the axial vertical burrows of the concave-side of the menisci, that originally face up-section, may help as a way-up criterion when dealing with rocks affected by low-grade penetrative metamorphism. La icnofacies Zoophycos-Chondrites presente en sedimentitas finogranulares cretácicas de la cordillera Occidental de Colombia, no existe -hasta donde se conoce- en las rocas isópicas coetáneas de las cordilleras Central y Oriental. Esta falta de la icnofacies se explica si se tiene en cuenta que a mediados y finales del Cretácico hubo lapsos durante los cuales se generaron cinturones de aguas anóxicas, que tocaron los fondos finogranulares de los dominios del mar epicontinental que cubrió el centro y el oriente colombianos, mas no alcanzaron los fondos óptimos para el desarrollo de Zoophycos en el océano en el que se originó el actual occidente de Colombia.  La identificación de la posición de la concavidad de los meniscos semilunares de las galerías verticales axiales de Zoophycos, que miraron hacia la superficie de depósito, permite su utilización en el discernimiento de

  10. Extensional Detachment faulting in melange rocks. Plurikilometres migration by W the External Zone (Cordillera Bética, Spain)

    Science.gov (United States)

    Roldán, Francisco Javier; Azañon, Jose Miguel; Rodríguez, Jose; Mateos, Rosa Maria

    2014-05-01

    The synthesis and correlation of units carried out in the continuous geological map (Roldán et al., 2012), has revealed a fragmentation of the carbonate outcrops belong to the Subbetic Domain (García-Hernández et al., 1980). Subbetic NW verging thrust and fold axial traces have not lateral continuity and Jurassic carbonate outscrops appear as klippes on the olistotromic unit. These ductile structures that can be observed in the internal structure of these jurassic blocks are unrelated to the brittle-ductile deformation bands observed at the basal pelitic levels. Basal detachments are rooted in: a) the Olistostromic unit, a Upper Langhian-Lower Serravallian breccia constituted by gypsum-bearing clay and marls; b) Cretaceous-Tertiary marly sedimentary rocks (Rodríguez-Fernández, et al., 2013) . In both kind of rocks, cataclastic structures allows to infer a top-to-the WSW displacement. Paleostress measurements, made on these detachments levels, are compatible with a extensional regime (Roldán et al., 2012). At the same time, the analysis and interpretation of subsurface data (seismic surveys and borehole testing) shows that the Subbetic Domain (External Subbetic, Molina 1987) are affected by westward low-angle normal faults. A balanced cross-section, based on morphological and cartographic data in the area between Sierra de Cabra and Sierra de Alta Coloma (Valdepeñas de Jaén), shows plurikilometric displacements which has been produced during Late Serravallian-Early Tortonian times. References: García-Hernández, M., López-Garrido, A.C., Rivas, P., Sanz de Galdeano, C., Vera, J.A. (1980): Mesozoic paleogeographic evolution of the zones of the Betic Cordillera. Geol. Mijnb. 59 (2). 155-168. Molina, J.M. (1987). Análisis de facies del Mesozoico en el Subbético. Tesis Doctoral, Univ. Granada. 518 p. Rodríguez-Fernández, J., Roldán, F. J., Azañón, J.M. y García-Cortés, A. (2013). El colapso gravitacional del frente orogénico a lpino en el Dominio Subb

  11. Monitoring tropical debris-covered glacier dynamics from high-resolution unmanned aerial vehicle photogrammetry, Cordillera Blanca, Peru

    Directory of Open Access Journals (Sweden)

    O. Wigmore

    2017-11-01

    Full Text Available The glaciers of the Cordillera Blanca, Peru, are rapidly retreating and thinning as a result of climate change, altering the timing, quantity and quality of water available to downstream users. Furthermore, increases in the number and size of proglacial lakes associated with these melting glaciers is increasing potential exposure to glacier lake outburst floods (GLOFs. Understanding how these glaciers are changing and their connection to proglacial lake systems is thus of critical importance. Most satellite data are too coarse for studying small mountain glaciers and are often affected by cloud cover, while traditional airborne photogrammetry and lidar are costly. Recent developments have made unmanned aerial vehicles (UAVs a viable and potentially transformative method for studying glacier change at high spatial resolution, on demand and at relatively low cost.Using a custom designed hexacopter built for high-altitude (4000–6000 m a. s. l.  operation, we completed repeat aerial surveys (2014 and 2015 of the debris-covered Llaca Glacier tongue and proglacial lake system. High-resolution orthomosaics (5 cm and digital elevation models (DEMs (10 cm were produced and their accuracy assessed. Analysis of these datasets reveals highly heterogeneous patterns of glacier change. The most rapid areas of ice loss were associated with exposed ice cliffs and meltwater ponds on the glacier surface. Considerable subsidence and low surface velocities were also measured on the sediments within the pro-glacial lake, indicating the presence of extensive regions of buried ice and continued connection to the glacier tongue. Only limited horizontal retreat of the glacier tongue was observed, indicating that measurements of changes in aerial extent alone are inadequate for monitoring changes in glacier ice quantity.

  12. Post-harvest practices linked with ochratoxin A contamination of coffee in three provinces of Cordillera Administrative Region, Philippines.

    Science.gov (United States)

    Barcelo, Jonathan M; Barcelo, Racquel C

    2018-02-01

    One of the emerging concerns in the Cordillera Administrative Region, Philippines is ochratoxin A (OTA) contamination in coffee. During 2015 to 2016, a total of 51 Arabica (Coffea arabica) coffee samples from Benguet province and 71 Robusta (Coffea canephora var. Robusta) coffee samples from the provinces of Ifugao and Kalinga were analysed for OTA contamination. The OTA-producing fungal contaminants during drying and storage of Arabica and Robusta coffee were Aspergillus niger and Aspergillus ochraceus. Ochratoxin A was more commonly detected in Robusta coffee (36.6%) than in Arabica coffee (21.6%). Among the contaminated samples, Robusta coffee cherries in the drying yard had the highest mean OTA level (120.2 μg kg -1 , n = 10) while roasted Robusta coffee beans had the lowest mean level (4.8 μg kg -1 , n = 9). The onset of contamination of Arabica coffee occurred during storage, with a mean OTA level of 46.7 μg kg -1 (n = 9). Roasted coffee had lower OTA content although five samples had levels >5.0 μg kg -1 . Pearson Chi-square analysis (χ 2 ) and Fisher's exact test revealed that several post-harvest practices involving non-removal of the husk or hull and mixing of defective coffee were significantly associated with the occurrence of OTA during drying and storage (p coffee in all stages of post-harvest and rapid reduction of moisture content particularly during drying.

  13. UNA ESPECIE NUEVA DE RANA DEL GÉNERO CHIASMOCLEIS (MICROHYLIDAE: GASTROPHRYNINAE DE LA CORDILLERA DEL CÓNDOR, ECUADOR

    Directory of Open Access Journals (Sweden)

    ANA ALMENDÁRIZ C.

    Full Text Available RESUMEN Se describe una especie nueva de rana del género Chiasmocleis de los bosques montanos del suroriente del Ecuador, en las laderas occidentales de la Cordillera del Cóndor, entre 1.025-1.630 m de altitud. En base a nuevas secuencias de ADN mitocondrial y nuclear presentamos las relaciones filogenéticas de la nueva especie y sus congéneres. La filogenia muestra una relación cercana a C. antenori, C. carvalhoi, C. magnova, y C. tridactyla. La nueva especie forma parte de un clado integrado por especies que previamente habían sido asignadas al género Syncope. Este clado es hermano de otro conformado por el resto de especies de Chiasmocleis. La nueva especie difiere de sus congéneres por su dorso café ladrillo a café obscuro (sepia cubierto por puntos diminutos blanco-amarillentos. Chiasmocleis parkeri sp. nov. se parece a Chiasmocleis antenori por la ausencia del dedo I, tanto en las manos como en los pies, pero difiere en la coloración, la disposición y tamaño de las manchas claras y la ausencia de una línea clara en la región cantal. La especie nueva presenta algunos rasgos que le distinguen de especies similares. Describimos el canto, caracterizado por tener notas sin pulsos y aportamos datos ecológicos de la localidad típica y áreas adyacentes.

  14. Time-lapse and UAV Thermal Imaging of Glacial and Periglacial Environments in the Peruvian Andes (Cordillera Blanca, Peru)

    Science.gov (United States)

    McKenzie, J. M.; Wigmore, O.; Aubry-Wake, C.; Mark, B. G.; Hellstrom, R. A.; Lautz, L.

    2015-12-01

    In the tropics, the acquisition of high-resolution geospatial data of high-mountain glacial and periglacial systems presents unique challenges due to remote site access and very high elevations. For glaciers and hydrologic systems, a key variable of interest is surface temperature as it constrains glacier melt rates, traces hydrologic processes, and is needed for the calibration of energy budget models. We present results from two studies that acquired high resolution temperature data from the Cuchillacocha Glacier, Peru (9.24°S, 77.21°W). The glacier resides on the western drainage of the Cordillera Blanca with an elevation range of 4700 to 6096 m. In the first study we use high resolution time-lapse infrared imagery (5-10 minute interval over 3 days; 0.6 m2 pixel size) to observe diel changes in the surface energy budget of the glacier and to demonstrate how radiation from bare rock adjacent to the glacier may affect melt rates. In the second study we use a newly developed, inexpensive unmanned aerial vehicle (UAV) for high resolution multispectral mapping of the glacier (2 cm resolution orthomosaic and 5 cm resolution DEM). We present results showing how the time-lapse and the high-resolution UAV imagery can be combined to further strengthen our understanding of the Cuchillacocha Glacier's energy budget and possible insights about turbulent heat fluxes. While the new instruments provide unprecedented data acquisition capabilities, there is an outstanding need for proper data correction. Spatial/thermal control points and post-processing algorithms are needed to produce quantifiable datasets. For example, our post-processed time-lapse imagery has an r2 > 0.9 after emissivity, transmissivity and offset corrections.

  15. Late Pleistocene and Holocene Hydroclimate Variability in the Tropical Andes from Alpine Lake Sediments, Cordillera de Mérida, Venezuela

    Science.gov (United States)

    Larsen, D. J.; Abbott, M. B.; Polissar, P. J.

    2014-12-01

    The tropics play a major role in the global hydrologic cycle and changes to tropical rainfall patterns have critical implications for water resources and ecosystem dynamics over large geographic scales. In tropical South America, late Pleistocene and Holocene precipitation variability has been documented in geologic records and associated with numerous external and internal variables, including changes in summer insolation, South American summer monsoon strength, Pacific Ocean sea surface temperatures, continental moisture recycling, and other climate processes. However, there are few records from the northern hemisphere tropical Americas, a key region for understanding interhemispheric linkages and the drivers of tropical hydroclimate variability. Here, we present a ~13 ka record of coupled hydroclimate and environmental changes from Laguna Brava, a small (~0.07 km2), hydrologically closed lake basin situated at 2400 m asl in the Cordillera de Mérida, Venezuela. Sediment cores collected from varying water depths and proximity to shore are placed in a chronologic framework using radiocarbon ages from terrestrial macrofossils, and analyzed for a suite of physical, bulk geochemical, and stable isotopic parameters. Compound specific hydrogen isotope (D/H) measurements of terrestrial plant waxes (long-chain n-alkanes) show a sharp increase in the late Pleistocene, followed by a long-term trend toward more negative values that suggest a ~20‰ decrease in the D/H ratios of South American tropical precipitation during the Holocene. This pattern is consistent in sign and magnitude to other South American precipitation reconstructions from both hemispheres, indicating interhemispheric similarities in tropical hydroclimate variability. Superimposed on this continent-scale trend are changes in moisture balance and environmental conditions in the Venezuelan Andes. We reconstruct these parameters at Laguna Brava at multidecadal and centennial resolution and evaluate this

  16. Monitoring tropical debris-covered glacier dynamics from high-resolution unmanned aerial vehicle photogrammetry, Cordillera Blanca, Peru

    Science.gov (United States)

    Wigmore, Oliver; Mark, Bryan

    2017-11-01

    The glaciers of the Cordillera Blanca, Peru, are rapidly retreating and thinning as a result of climate change, altering the timing, quantity and quality of water available to downstream users. Furthermore, increases in the number and size of proglacial lakes associated with these melting glaciers is increasing potential exposure to glacier lake outburst floods (GLOFs). Understanding how these glaciers are changing and their connection to proglacial lake systems is thus of critical importance. Most satellite data are too coarse for studying small mountain glaciers and are often affected by cloud cover, while traditional airborne photogrammetry and lidar are costly. Recent developments have made unmanned aerial vehicles (UAVs) a viable and potentially transformative method for studying glacier change at high spatial resolution, on demand and at relatively low cost.Using a custom designed hexacopter built for high-altitude (4000-6000 m a. s. l. ) operation, we completed repeat aerial surveys (2014 and 2015) of the debris-covered Llaca Glacier tongue and proglacial lake system. High-resolution orthomosaics (5 cm) and digital elevation models (DEMs) (10 cm) were produced and their accuracy assessed. Analysis of these datasets reveals highly heterogeneous patterns of glacier change. The most rapid areas of ice loss were associated with exposed ice cliffs and meltwater ponds on the glacier surface. Considerable subsidence and low surface velocities were also measured on the sediments within the pro-glacial lake, indicating the presence of extensive regions of buried ice and continued connection to the glacier tongue. Only limited horizontal retreat of the glacier tongue was observed, indicating that measurements of changes in aerial extent alone are inadequate for monitoring changes in glacier ice quantity.

  17. Unraveling Tropical Mountain Hydroclimatology by Coupling Autonomous Sensor Observations and Climate Modeling: Llanganuco Valley, Cordillera Blanca, Peru.

    Science.gov (United States)

    Hellstrom, R. A.; Fernandez, A.; Mark, B. G.; Covert, J. M.

    2015-12-01

    Northern Peru will face critical water resource issues in the near future as permanent ice retreats. Much of current global and regional climate research neglects the meteorological forcing of lapse rates and valley wind dynamics on critical components of the Peruvian Andes' water-cycle. In 2004 and 2005 we installed an autonomous sensor network (ASN) within the glacierized Llanganuco Valley, Cordillera Blanca (9°S), consisting of discrete, cost-effective, automatic temperature loggers located along the valley axis and anchored by two automatic weather stations. Comparisons of these embedded atmospheric measurements from the ASN and climate modeling (CM) by dynamical downscaling using the Weather Research and Forecasting (WRF) model elucidate distinct diurnal and seasonal characteristics of the mountain valley winds and lapse rates. Wind, temperature, humidity, and cloud simulations by WRF suggest that thermally driven valley winds converging with easterly flow aloft enhance late afternoon and evening cloud development which helps explain detected nocturnal precipitation maxima measured by the ASN. We attribute sustained evapotranspiration (ET), as estimated by the FAO-56 Penman-Monteith model, to an abundance of glacial melt-water during the dry season and strong pre-noon solar heating during the wet season. Furthermore, the extreme diurnal variability of along-valley-axis lapse rates and valley wind detected from ground observations and confirmed by dynamical downscaling demonstrate the importance of realistic scale parameterizations of the boundary layer to improve regional CM projections in mountainous regions. Our findings portray ET as an integral yet poorly represented process in Andean hydroclimatology. We show that coupling ASN and CM can improve understanding of multi-scale atmospheric and associated hydrological processes in mountain valleys.

  18. Calculo Preliminar de la Tasa de Meteorización del Batolito Antioqueño, Cordillera Central, Colombia

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    Carolina Garcia

    2004-12-01

    Full Text Available Este trabajo es una estimación preliminar del tiempo necesario para generar la espesa capa de saprolito que caracteriza el perfil de meteorización actual de un batolito cuarzodiorítico cretácico que aflora en altiplanos de la Cordillera Central de Colombia, entre 5º50' y 7º00' de latitud Norte y 74º50' y 75º35' de longitud Oeste y a alturas entre 750 y 2700 m.Se utilizan datos obtenidos previamente mediante el análisis de la composición química de las aguas superficiales de cuatro cuencas con áreas diferentes, ubicadas sobre el Batolito Antioqueño, al este de Medellín. Los cáculos se hicieron con el método basado en la pérdida de componentes en solución utilizando diferentes valores de solutos. Al utilizar la pérdida de sílice se obtiene un tiempo de meteorización de unos 6 x 10 6 años, comparable con el obtenido mediante la datación de las cenizas volcánicas mas antiguas que recubren la topografía actual y que indican la fecha mínima de configuración de la superficie de erosión.A pesar de resultar de una serie de suposiciones simplificadoras, este resultado es interesante y justifica la realización de determinaciones mas detalladas. Confirma la larga preservación de superficies de erosión antiguas conformadas sobre un saprolito que desde hace varios millones de años no ha sido sometido a una erosión profunda, fenómeno poco común en una zona tectónicamente activa como la estudiada.

  19. Una especie nueva de rana arbórea del género Hyloscirtus (Amphibia: Anura: Hylidae de la Cordillera del Cóndor

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    Ana Almendáriz

    2014-01-01

    Full Text Available Las ranas ecuatorianas del género Hyloscirtus incluyen 16 especies descritas, de las cuales 11 pertenecen al grupo H. larinopygion. Su distribución se limita a los flancos de la Cordillera de los Andes, tanto al oriente como al occidente. Una evaluación de la herpetofauna en el sector meridional de la Cordillera del Cóndor (bosques montanos sobre mesetas de arenisca en la provincia de Zamora Chinchipe, Ecuador, condujo al descubrimiento de una especie nueva del grupo que describimos aquí como Hyloscirtus condor sp. nov.; se analizan los renacuajos, las llamadas de anuncio y se estima las relaciones filogenéticas de la especie nueva y de las especies relacionadas en base a nuevas secuencias de los genes mitocondriales 12S, tRNA Val y 16S, con un total de hasta 2508 bp. Los resultados muestran que el grupo H. larinopygion está conformado por dos clados, uno distribuido en los Andes norte y centro de Ecuador y el otro al sur. La nueva especie pertenece al clado sur y es hermana de H. tapichalaca y de una especie aparentemente no descrita de la Provincia Morona Santiago. La especie nueva difiere de sus congéneres por su patrón de coloración dorsal, que consiste de puntos amarillo obscuro en un fondo canela. Es la especie más grande del grupo H. larinopygion y comparte con H. tapichalaca la presencia de una espina prepólica grande y curvada y brazos hipertrofiados. La especie nueva habita un área remota y bien conservada de la Cordillera del Cóndor. El descubrimiento de ésta y otras especies nuevas del mismo lugar denota la importancia biológica del área y motivan al desarrollo de planes de conservación.

  20. The analysis of remote sensing data to delineate landsystem tracts in proglacial valleys in the Río Santa Basin, Cordillera Blanca, Perú

    Science.gov (United States)

    Narro Perez, R. A.; Eyles, C.

    2016-12-01

    The Río Santa Basin is an important glacially-influenced basin of social, economic and cultural importance to the country of Perú. It produces a large portion of Peru's hydroelectricity, is an important agricultural area, and hosts two major mining complexes. The Río Santa receives its water from precipitation, glacial runoff from over 450 glaciers draining the Cordillera Blanca, and groundwater discharge. Despite being the largest tropical glacier ice field in the world, the area of glacial coverage in the Cordillera Blanca has decreased from 825 km2 in 1930 to 528 km2 in 2003. It is estimated that glacial runoff contributes 10-20% of the Río Santa's annual flow but during the dry season it can contribute up to 66% of water flow with groundwater supplying the remainder. The contribution of glacial meltwater makes the Río Santa less susceptible to discharge variability caused by inter-annual variation in precipitation. Due to decreased meltwater contributions, the urban centers and rural communities in the basin are expected to face severe water scarcity in the future, especially during the dry season. This poster will show the results of a remote sensing survey, using Google Earth and LiDAR data, to delineate landsystem tracts and components in several proglacial valleys in the Cordillera Blanca. The results of this survey allow detailed documentation of the geomorphological evolution of the landscape which will in turn allow a better understanding of the glacial history and subsurface geology of the area. These findings will better inform current hydrogeological models used to determine the sustainability of water resources in the Río Santa basin. Understanding the landsystem architecture, sedimentology and subsurface stratigraphy of the basin will also allow these models to more accurately predict the impact that future climate change will have on water resources and the people of the Río Santa basin.

  1. Assessing the variability of glacier lake bathymetries and potential peak discharge based on large-scale measurements in the Cordillera Blanca, Peru

    Science.gov (United States)

    Cochachin, Alejo; Huggel, Christian; Salazar, Cesar; Haeberli, Wilfried; Frey, Holger

    2015-04-01

    Over timescales of hundreds to thousands of years ice masses in mountains produced erosion in bedrock and subglacial sediment, including the formation of overdeepenings and large moraine dams that now serve as basins for glacial lakes. Satellite based studies found a total of 8355 glacial lakes in Peru, whereof 830 lakes were observed in the Cordillera Blanca. Some of them have caused major disasters due to glacial lake outburst floods in the past decades. On the other hand, in view of shrinking glaciers, changing water resources, and formation of new lakes, glacial lakes could have a function as water reservoirs in the future. Here we present unprecedented bathymetric studies of 124 glacial lakes in the Cordillera Blanca, Huallanca, Huayhuash and Raura in the regions of Ancash, Huanuco and Lima. Measurements were carried out using a boat equipped with GPS, a total station and an echo sounder to measure the depth of the lakes. Autocad Civil 3D Land and ArcGIS were used to process the data and generate digital topographies of the lake bathymetries, and analyze parameters such as lake area, length and width, and depth and volume. Based on that, we calculated empirical equations for mean depth as related to (1) area, (2) maximum length, and (3) maximum width. We then applied these three equations to all 830 glacial lakes of the Cordillera Blanca to estimate their volumes. Eventually we used three relations from the literature to assess the peak discharge of potential lake outburst floods, based on lake volumes, resulting in 3 x 3 peak discharge estimates. In terms of lake topography and geomorphology results indicate that the maximum depth is located in the center part for bedrock lakes, and in the back part for lakes in moraine material. Best correlations are found for mean depth and maximum width, however, all three empirical relations show a large spread, reflecting the wide range of natural lake bathymetries. Volumes of the 124 lakes with bathymetries amount to 0

  2. Caracterización de superficies de erosión mediante geomorfología cuantitativa, Altiplano Antioqueño, Cordillera Central de Colombia

    OpenAIRE

    Xavier Bustos; Mauricio A. Bermúdez; Gloria M. Toro; Matthias Bernet; Otilio Rojas; María I. Marín

    2013-01-01

    En el presente trabajo se caracterizan treinta y cinco superficies de erosión (SE) en la Cordillera Central de Colombia mediante geomorfología cuantitativa y análisis digital de terreno. Utilizando modelos digitales de elevación (MDE) se derivaron las curvas hipsométricas para dichas superficies, y se comparan los resultados desde dos ópticas. Primero, mediante técnicas geoestadísticas utilizando subrutinas elaboradas bajo R, en combinación con el Lenguaje de Consulta Estruct...

  3. THE STRATIGRAPHY OF THE UPPER BATHONIAN TO MIDDLE OXFORDIAN SUCESSION OF THE ARAGONESE BRANCH OF THE CORDILLERA IBÉRICA (SPAIN AND ITS EUROPEAN CONTEXT

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    KEVIN N. PAGE

    2004-03-01

    Full Text Available The Upper Bathonian-Middle Oxfordian succession of the Aragonese branch of the Cordillera Ibérica is one of the most completely developed in Europe and includes localities of international importance for Jurassic bio- and chronostratigraphy. Of particular importance are a potential stratotype for the Upper Bathonian of North West Europe and reference sections for a number of Submediterranean Province Middle Oxfordian biostratigraphic units. The intervening Callovian sequence, albeit locally strongly condensed, also includes faunas of key stratigraphical importance. The sequence of stratigraphically important ammonite faunas for this interval is here reviewed and placed in its European context.

  4. Del asentamiento minero al espacio continental: Chuquicamata (Chile y la contribución de la minería a la configuración del territorio y el desarrollo social y económico de la Región de Antofagasta durante el siglo XX

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    EUGENIO GARCES FELIÚ

    2010-04-01

    Full Text Available El presente paper tiene por objetivo analizar las contribuciones de Chuquicamata al desarrollo territorial, social y económico de la II Región de Antofagasta durante el siglo XX, a partir de su condición de complejo industrial y company town minero, que evoluciona desde las rentas y aportes propios de un campamento del cobre hasta su despliegue a escala regional, con alcances y encadenamientos continentales, contribuyendo al desarrollo social y económico de la región y el país. En esta perspectiva, el Norte de Chile y, en particular esta región, ostentan importantes ventajas comparativas y competitivas, extensivas al siglo XXI, tanto para la explotación de minerales como para su encadenamiento con otros sectores productivos, en un proceso que genera nuevas configuraciones de ordenamiento territorial, basadas no sólo en la dinámica urbana de los company totvns sino que también en la extensión y complejidad del "territorio minero", activado económicamente por la minería.This article analyzes the contributions of Chuquicamata to the territorial, social and economic development of the II Region of Antofagasta during the twentieth century. The process begins with the local contributions of an industrial complex and company town, that evolves from profits and contributions specific to a copper mining settlement to a situation of regional significance, generating continental economic relations and linkages which contribute to the social and economic development of the region and he country. From this perspective, Northern Chile, and this region in particular, hold important comparative and competitive advantages that extend into the twenty first century, both for the exploitation of mineral resources and for increasing linkages with other productive sectors, in a process that generates new spatial configurations, based not only on the urban dynamics of the company town, but also through the extent and complexity of the mining territory

  5. MUCHO MÁS QUE SÓLO APROVISIONAMIENTO LÍTICO: ACTIVIDADES EN CANTERAS Y PRÁCTICAS SOCIALES EN LAS FUENTES DE PAMPA OESTE, QUEBRADA SECA Y PUNTA DE LA PEÑA (ANTOFAGASTA DE LA SIERRA, CATAMARCA / Much more than just lithic procurement: activities at quarrie

    Directory of Open Access Journals (Sweden)

    Federico Miguel Bobillo

    2015-06-01

    Full Text Available En este trabajo se abordan las canteras y talleres asociados de Punta de la Peña, Quebrada Seca y Pampa Oeste, en Antofagasta de la Sierra (Catamarca, con el objeto de explorar la multiplicidad de actividades y prácticas sociales involucradas en la utilización de dichas fuentes. Se trata de tres fuentes de vulcanitas intensamente explotadas a lo largo de la secuencia prehispánica del área. De esta forma, se toma a las canteras no sólo como un depósito de rocas útiles para la subsistencia, sino como un escenario social donde confluyen y se materializan diferentes prácticas y expresiones sociales. Así, a la explotación de las rocas se suman toda una serie de tareas vinculadas, por ejemplo, con prácticas de enseñanza/aprendizaje y actividades de subsistencia, procesamiento/consumo y rituales. Esta aproximación considera a las canteras desde una perspectiva orientada a abordar las elecciones y prácticas llevadas a cabo por los agentes en contextos de aprovisionamiento, partiendo de la base de que estos actúan desarrollando una diversidad de actividades conectadas en torno a la apropiación de un recurso específico.Abstract  Quarries and workshops at Punta de la Peña, Quebrada Seca and Pampa Oeste (Antofagasta de la Sierra, Catamarca are considered in this paper. The goal is to explore the multiplicity of social activities and practices involved in the use of these quarries. These three vulcanite sources were intensively exploited during the pre-Hispanic history of the region. In this way, quarries are not only considered rock deposits useful for subsistence, but also a social scenario where different social practices and social expressions converge and are materialized. Thereby, series of linked tasks are added to rock exploitation. For example, teaching/learning practices and subsistence, processing/consumption and ritual activities. This approach considers quarries from a perspective oriented to the analysis of elections and

  6. Lista anotada y clave para las ranas (género Eleutherodactylus chocoanas del Valle del Cauca, y apuntes sobre las especies de la Cordillera Occidental adyacente

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    Lynch John Douglas

    1999-11-01

    Full Text Available Twenty-three species of the genus Eleutherodactylus are reported fram 24 localities in the western lowlands of Valle del Cauca, Colombia, with notes on their identificacion and distributions. Up to 16 species have been taken from a single site. The cloud forest fauna of  Eleutherodactylus found on the Cordillera Occidental above the drainages of the Anchicayá, Cajambre, Calima, and Dagua rivers consists of 24 species with up to 18 species being found in a single site.Se da información sobre la identificación y las distribuciones de 23 especies del género Eleutherodactylus de 24 sitios de las tierras bajas del occidente del Valle del Cauca, Colombia. Hasta 16 especies fueron registradas del mismo sitio. La fauna de Eleutherodactylus de los bosques nublados de la Cordillera Occidental en los drenajes de los ríos Anchicayá, Cajambre, Calima, y Dagua consta de 24 especies, con hasta 18 encontradas en un mismo sitio.

  7. Market access and community size influence pastoral management of native and exotic livestock species: A case study in communities of the Cordillera Real in Bolivia's high Andean wetlands.

    Science.gov (United States)

    Struelens, Quentin; Gonzales Pomar, Karina; Loza Herrera, Susi; Nina Huanca, Gaby; Dangles, Olivier; Rebaudo, François

    2017-01-01

    Grazing areas management is of utmost importance in the Andean region. In the valleys of the Bolivian Cordillera Real near La Paz, pastoralism constitutes the traditional way for people to insure food security and economical sustainability. In these harsh mountains, unique and productive wetlands sustained by glacial water streams are of utmost importance for feeding cattle herds during the dry season. After the colonization by the Spanish, a shift in livestock species has been observed, with the introduction of exotic species such as cows and sheep, resulting in a different impact on pastures compared to native camelid species-llamas and alpacas. Here we explored some of the social-economical and environmental drivers that motivate Bolivian pastoralists to prefer exotic over native livestock species, based on 36 household surveys in the Cordillera Real. We constructed a Partial Least Squares Structural Equation Model in order to assess the relationships between these drivers. Our results suggest that the access to market influenced pastoralists to reshape their herd composition, by increasing the number of sheep. They also suggest that community size increased daily grazing time in pastures, therefore intensifying the grazing pressure. At a broader scale, this study highlights the effects of some social-economical and environmental drivers on mountain herding systems.

  8. Tracing society in climate change: Societal negotiations and physical dynamics of water under climate change conditions in the Cordillera Blanca region, Peru

    Science.gov (United States)

    Neuburger, Martina; Gurgiser, Wolfgang; Maussion, Fabien; Singer, Katrin; Kaser, Georg

    2017-04-01

    Natural scientists observe and project changes in precipitation and temperature at different spatio-temporal scales and investigate impacts on glaciers and hydrological regimes. Simultaneously, social groups experience ecological phenomena as linked to climate change and integrate them into their understanding of nature and their logics of action, while political actors refer to scientific results as legitimization to focus on adaptation and mitigation strategies on global, national and regional/local level. However, natural and socio-political changes on various scales (regarding time and space) are not directly interlinked, but are communicated by energy and material flows, by discourses, power relations and institutional regulations. In this context, it remains still unclear how natural dynamics are (dis)entangled with societal processes in their historical dimensions and in their interrelations from global via national to regional and local scales. Considering the Cordillera Blanca region in Peru as an example, we analyze the intertwining of scales (global, national, regional, local) and spheres (natural, political, societal) to detect entanglements and disconnections of observed processes. Using the methodology of a time line, we present precipitation variability and glacier recession at different scales, estimate qualitative water availability and investigate the links to the implementation of international and national political programs on climate change adaptation in the Cordillera Blanca region focusing on water and agrarian programs. Finally, we include supposedly contradictory reports of rural population on climate change and related impacts on water availability and agricultural production to analyze the (dis)entanglement due to changing power relations and dominant discourses.

  9. Efecto de la zona de vida y la altitud en la mortalidad y adaptabilidad al primer ano de especies forest ales en la cordillera volcanica central, Costa Rica

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    Yorleny Badilla

    2002-01-01

    Full Text Available Se presenta los resultados de la mortalidad y adaptabilidad a los 6 y 12 meses de edad, de las especies forestales cipres (Cupressus lusitanica, eucalipto de altura (Eucalyptus globulus, pino patula (Pinus patula, pino radiata (Pinus radia- fa, roble encino (Quercus coopeyensis,jaul (Al- nus acuminata, cedro dulce (Cedrela tonduzii y tirra (Ulmus mexicana. De cada especie fueron plantadas 4 repeticiones dentro de cada una de las 3 zonas de vida de mayor representatividade la Cordillera Volcanica Central de Costa Rica, predesde los 1000 a los 2000 m de altitud. Se regis- tro una tendencia de mayor mortalidad conforme aumento la pluviosidad. Las 3 especies confferas mostraron desde los 6 meses la menor mortalidad «15% y mayor estabilidad en todas las zonas de pluvida; presentaron un alto potencial de reforesta- cion en toda la Cordillera Volcanica Central. Las especies cella dulce, tirra y jaul conformaron un grupo de especies con una mortalidad elevada, que se estabiliz6 hasta el ano de plantadas. Las especies eucalipto de altura y fable conformaron el grupo de mayor mortalidad (>50% y de adap- tabilidad mas lenta. Sin embargo, el eucalipto de altura mostro un buen crecimiento en sitios plu- viales. Un mayor cuidado de la calidad del mate- adaptrial de reforestaci6n y el empleo de tecnicas de plantaci6n como los camellones, la aporca y el drenaje, son esenciales para poder reforestar en nurszonas de altura con una elevada pluviosidad.

  10. Market access and community size influence pastoral management of native and exotic livestock species: A case study in communities of the Cordillera Real in Bolivia's high Andean wetlands.

    Directory of Open Access Journals (Sweden)

    Quentin Struelens

    Full Text Available Grazing areas management is of utmost importance in the Andean region. In the valleys of the Bolivian Cordillera Real near La Paz, pastoralism constitutes the traditional way for people to insure food security and economical sustainability. In these harsh mountains, unique and productive wetlands sustained by glacial water streams are of utmost importance for feeding cattle herds during the dry season. After the colonization by the Spanish, a shift in livestock species has been observed, with the introduction of exotic species such as cows and sheep, resulting in a different impact on pastures compared to native camelid species-llamas and alpacas. Here we explored some of the social-economical and environmental drivers that motivate Bolivian pastoralists to prefer exotic over native livestock species, based on 36 household surveys in the Cordillera Real. We constructed a Partial Least Squares Structural Equation Model in order to assess the relationships between these drivers. Our results suggest that the access to market influenced pastoralists to reshape their herd composition, by increasing the number of sheep. They also suggest that community size increased daily grazing time in pastures, therefore intensifying the grazing pressure. At a broader scale, this study highlights the effects of some social-economical and environmental drivers on mountain herding systems.

  11. Mineralogía de los materiales de la Formación de La Viñuela (Cordilleras Béticas

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    Galán, E.

    1984-12-01

    Full Text Available Mineralogy of several samples from the Viñuela Formation,Lower Burdigalian (Vélez Málaga, Cordilleras Béticas, has been studied. Materials are composed of abundant microfauna. and pebbles of micaschits, quartzites and other materials, from the Alpujárrides and Maláguides Nappes, cemented by a micritic matrix . Most samples contain zeolites (clinoptilolite, mordenite and analcime, and illite chlorite, interstratified clay minerals, montmorillonite and opal C-T. A diagenetic genesis for zeolites is suggested.

    Se ha estudiado la composición mineralógica de unas muestras de la serie tipo de la Formación de La Viñuela (norte de Vélez Málaga, Cordilleras Béticas, datadas como Burdigaliense inferior. Se trata de sedimentos marinos carbonatados micríticos, con abundante microfauna. que cementan cantos de micaesquistos, cuarcitas y otros materiales procedentes de los mantos alpujárrides y maláguides. En gran parto de estas muestras se han encontrado zeolitas (clinoptilolita, mordenita y analcima, así como illita, clorita, interestratificados, montmorillonita y ópalo C-T. Se atribuye a las zeolitas un origen diagenético.

  12. On glaciation of the southern Andes with special reference to the Penı´nsula de Taitao and adjacent Andean cordillera (˜46°30's)

    Science.gov (United States)

    Heusser, C. J.

    2002-10-01

    Ice fronts in the southern Andes during late Wisconsin-Weichselian glaciation reached maxima early and late in oxygen isotope stage 2. The first maximum occurred between 29,400 and 22,300 14C yr BP, and the second is centered around 15,000 14C yr BP. Glaciers at different latitudes varied in size, apparently in response to maximum levels of precipitation from the moisture-bearing southern Westerlies. Following deglaciation, which was reached in the interior midlatitude cordillera earlier than 12,300 14C yr BP, a late glacial readvance of Younger Dryas age is indicated by an increasing number of glacial geomorphic and paleoecological records, but it remains controversial. During stage 2, the cordillera supported a complex of ice caps and valley glaciers. On the Penı´nsula de Taitao and to the south, glaciers reaching low altitudes were evidently small compared with the large piedmont lobes that covered the sector encompassing the Región de los Lagos-Isla Grande de Chiloé to the north. Flowing from an icecap on Taitao, valley glaciers became coalesced only locally, thereby giving rise to small piedmont lobes. Adjacent to Taitao in the Andes, where there is little studied evidence of stage 2 glaciation, the oldest dated advances appear to be late Holocene. Glaciers at this latitude, situated in the Tres Montes fracture zone at the Antarctic-Nazca-South American triple plate junction, have been subjected to tectonic activity.

  13. Mineralización de talco asociada a los cuerpos ultramáficos de la Faja del Río de Las Tunas, Cordillera Frontal de Mendoza

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    Gargiulo, María Florencia

    2011-12-01

    Full Text Available Talc mineralization related to the ultramafic bodies of the Río de Las Tunas belt, Frontal Cordillera of Mendoza province. This contribution shows the main characteristics of the talc mineralization related to the Río de Las Tunas ultramafic bodies in the Salamanca Mining District, Frontal Cordillera of Mendoza province. According to the parageneses defined on the studied samples, three generations of talc were established: 1º crystallized in metaperidotites and related to the prograde stage of the regional metamorphism; 2º crystallized inreaction zones (mostly in the talc zone developed at the boundary between metaperidotites and their country-rocks.These reaction zones evidence a metasomatic process due to geochemical gradient between the ultramafic body and their country-rocks. This process was developed during the retrogression of the regional metamorphic cycle. 3º Talc present in shear-zones that cut across the ultramafic bodies. The extreme serpentinization of the ultramaficbodies is concentrated in shear-zones where the serpentine is subsequently replaced by talc ± carbonates related with a hydrothermal stage. Aqueous fluids relatively enriched in CO2 flowed through these shear-zones causing the cease of serpentine formation favoring the talc and/or carbonates. Mined talc deposits are those in shear zones and reaction zones. They are mostly industrial-, asbestine- or talcschist-type. The talc related to the hydrothermal stage can locally reach first and extra qualities.

  14. Descripción de las larvas de dos centrolénidos (Anura: Centrolenidae del noroccidente de la Cordillera Oriental, Colombia

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    Marco Rada

    2007-01-01

    Full Text Available Se describen las larvas de dos especies de la familia Centrolenidae (Hyalinobatrachium ibama y Cochranella daidalea procedentes del flanco occidental de la cordillera Oriental en el departamento de Norte de Santander, Colombia. En la descripción de las larvas, además de las características morfológicas tradicionales, se incorporaron nuevos elementos de juicio como la longitud del tubo cloacal, la forma del rostro, el patrón de color y la posición del espiráculo, los cuales resultaron ser informativos y muy útiles en la diferenciación de las especies. Se proporciona una discusión acerca de la validez taxonómica de algunos de los caracteres morfológicos empleados usualmente en las descripciones y comparaciones de los renacuajos de la familia Centrolenidae.We describe herein the larvae of two species of the family Centrolenidae (Hyalinobatrachium ibama and Cochranella daidalea from the Department of Norte de Santander on the western flank of the Cordillera Oriental, Colombia. In order to provide an adequate description, we incorporate new elements such as: vent-tube length, snout shape, color pattern and spiracle position. A discussion about the taxonomic validity of some tadpole morphological characteristics traditionally used in descriptions and comparisons of the family Centrolenidae is provided.

  15. Modelling cascading and erosional processes for glacial lake outburst floods in the Quillcay catchment, Huaraz, Cordillera Blanca, Peru

    Science.gov (United States)

    Baer, Patrick; Huggel, Christian; Frey, Holger; Chisolm, Rachel; McKinney, Daene; McArdell, Brian; Portocarrero, Cesar; Cochachin, Alejo

    2016-04-01

    Huaraz as the largest city in Cordillera Blanca has faced a major disaster in 1941, when an outburst flood from Lake Palcacocha killed several thousand people and caused widespread destruction. Recent studies on glacial lake outburst flood (GLOF) modelling and early warning systems focussed on Lake Palcacocha which has regrown after the 1941 event, from a volume of half a million m3 in 1974 to a total volume of more than 17 million m3 today. However, little research has been conducted so far concerning the situation of other lakes in the Quillcay catchment, namely Lake Tullparaju (12 mill. m3) and Cuchillacocha (2.5 mill. m3), which both also pose a threat to the city of Huaraz. In this study, we modelled the cascading processes at Lake Tullparaju and Lake Cuchillacocha including rock/ice avalanches, flood wave propagation in the lake and the resulting outburst flood and debris flows. We used the 2D model RAMMS to simulate ice avalanches. Model output was used as input for analytical 2D and 3D calculations of impact waves in the lakes that allowed us to estimate dam overtopping wave height. Since the dimension of the hanging glaciers above all three lakes is comparable, the scenarios in this study have been defined similar to the previous study at Lake Palcacocha. The flow propagation model included sediment entrainment in the steeper parts of the catchment, adding up to 50% to the initial flow volume. The results for total travel time as well as for inundated areas and flow depth and velocity in the city of Huaraz are comparable to the previous studies at Lake Palcacocha. This underlines the importance of considering also these lakes within an integral hazard analysis for the city of Huaraz. A main challenge for modelling GLOFs in the Quillcay catchment using RAMMS is the long runout distance of over 22 km combined with the very low slope gradient of the river. Further studies could improve the process understanding and could focus on more detailed investigations

  16. Unraveling an antique subduction process from metamorphic basement around Medellín city, Central Cordillera of Colombian Andes

    Science.gov (United States)

    Bustamante, Andres; Juliani, Caetano

    2011-10-01

    varies between 400 and 555 °C at pressures of 5-6 kbar in the retrograde metamorphic path. The El Retiro rocks evidence strong decompression with narrow variation in temperature, showing pressure values between 8.7 and 2.7 kbar at temperatures of 740-633 °C. These metamorphic fragments of the basement in the Central Cordillera of the Colombian Andes could represent a close relationship with an antique subduction zone.

  17. EXPERIENCIAS DE CORDILLERA, ECOS DE FRÍO: RELATOS CRUZADOS ENTRE CHILE Y QUITO EN EL SIGLO XVI

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    Alejandra Vega

    2011-11-01

    Full Text Available La narración de la secuencia de la conquista del Perú nos enfrenta con la fijación de dos episodios diferentes aunque articulados: la jornada a Quito de Pedro de Alvarado en 1534 y la expedición a Chile de Diego de Almagro, entre 1535 y 1536, que incluyen, ambas, una travesía cordillerana. El presente artículo discute los ecos que pueden rastrearse de los relatos acerca de estas expediciones en un conjunto de obras redactadas en torno a 1550 (Gonzalo Fernández de Oviedo, Francisco López de Gómara, Pedro Cieza de León y Agustín de Zárate. A partir de convergencias y diferencias inesperadas en estos textos, se discute la importancia de la circulación oral de historias entre los conquistadores del Perú. Se plantea que la práctica social de la conversación oral permitió fijar, además de estas historias, una temprana conceptualización cristiana de los límites del Tawantinsuyu. En ella se concibió a Quito y Chile como las marcas fronterizas del espacio recién conquistado, permitiendo que ambos territorios se superpusieran al caracterizarse a partir a un mismo conjunto de imágenes sobre la experiencia de la cordillera.In the Hispanic narrative of the conquest of Peru, we can identify two different yet related episodes: Pedro de Alvarado's journey to Quito in 1534 and the expedition to Chile commanded by Diego de Almagro in 1535-1536. This article discusses the echoes than can be pinpointed in the accounts of both experiences in a corpus of texts written or printed around 1550 (Gonzalo Fernández de Oviedo, Francisco López de Gómara, Pedro Cieza de León and Agustín de Zárate. By tracing unexpected similarities and differences, this proposal discusses the importance of oral circulation of histories amongst Peruvian conquistadors. The features of conversation, as a social practice, allowed the register ofan early Christian conceptualization of the Tawantinsuyu territory. Here Quito and Chile became frontier marks of the

  18. The Tastil batholith (Cordillera Oriental, Argentina): a case of lower Cambrian extensional-related magmatism in the border of Gondwana.

    Science.gov (United States)

    Hongn, F.; Tubía, J. M.; Aranguren, A.; Mon, R.

    2003-04-01

    The Tastil batholith composed of gray granodiorite, red granite and dacite porphiry, intrudes into weakly metamorphosed turbidites (usually included in the Puncoviscana Formation) and into Cambrian shelf sandstones belonging to the Lower-Middle Cambrian Mesón Group deposited in an intracontinental extensional basin. Tremadocian fossiliferous conglomerates overlying the sandstones of the Mesón Group incorporate red granite pebbles in the Angosto de la Quesera section, the classical section for interpreting the stratigraphic relationships of the Tastil batholith. U-Pb zircon ages from a dacite porphiry (526 Ma) and red granite (517 Ma) are consistent with such field relationships. This new view of the Tastil batholith implies that the previous interpretations of the basement, based on the supposed unconformity between the Mesón Group and the underlying red granite, and hence including the Tastil batholith in the basement, can not longer be sustained. The batholith emplacement is not related with the shortening happened during the late evolution of the Puncoviscana Formation (Pampean cycle) as always was interpreted, but with the extensional tectonics responsible for the development of the Mesón Group basin (Famatinian cycle). Along central and northern Argentina, the basement records a wide spectrum of sedimentary, deformational, magmatic and metamorphic processes occurred at different crustal levels during the Latest Neoproterozoic and the Cambrian. In this regard, the deposition of the Mesón Group and the intrusion of the Tastil batholith within the Cordillera Oriental can be correlated with the magmatism and the high-T/low-P metamorphism developed, at deeper levels, 530 to 500 Ma ago within the basement of the Puna and Sierras Pampeanas. In the same way, the sedimentation and igneous processes documented at shallower levels in the Sierras Pampeanas took place in this extensional tectonic scenario. The available data point to an overall extensional tectonics

  19. Application of terrestrial scanning LIDAR to study the evolution of Quisoquipina Glacier in the Cordillera Vilcanota, Cusco - Peru

    Science.gov (United States)

    Montoya, Nilton; Macedo, Nicolas; Sanchez, Olivier; Huggel, Christian; Giraldez, Claudia; Schauwecker, Simone; Drenkhan, Fabian; Frey, Holger; Molina, Edwin; Sikos, Felipe

    2017-04-01

    Tropical glaciers are highly sensitive to alterations in climate and therefore good indicators for global climate change. Glaciers located in Peru represent 71% of all tropical glaciers in the world, and have shown a significant area reduction of about 43% within the last 40 years mainly due to the increase in surface temperature. Tropical glaciers play a particular role as freshwater reservoirs and buffers to river discharge variability and water scarcity within a pronounced wet and dry season. Their monitoring is extraordinarily important but few studies exist on mass balance. The Cordillera Vilcanota, at the origin of the Rio Vilcanota-Urubamba, contains about 25% of all glaciers in Peru. In recent decades, glacier shrinkage has accelerated in this mountain range. Between 1988 and 2010, glacier area was reduced at an annual rate of about 4 km2 (1.1 %) from some 360 km2 to about 270 km2 (25%). A total volume loss of 40-45% (from 17-20 km3 to 9.2-12.4 km3) can be estimated for the period 1962-2006, with an accelerated rate since the 1980s. Terrestrial scanning LIDAR (LIght Detection And Ranging) surveys represent nowadays the most powerful tool to accurately map its inaccessible glacier surfaces. A laser scanner enables researchers to capture laser range data at a rate of thousands of x, y, z and laser-intensity points per second; such data can be used to construct a very accurate 3D model of the surveyed surface. We used a terrestrial LiDAR sensor (Optech ILRIS 3D-LR) for intensively monitoring the changes occurred at volume and front glacier: the Quisoquipina glacier. In August and October 2015, August and December 2016, four terrestrial scanning LIDAR surveys have been carried out in order to monitor the evolution of the glacier. The comparison between repeated surveys showed significant retreats in the front, area and volume of the glacier (e.g. lost volume 375000 m3 between august 2015 and December 2016, in 80812 m2 of area of study).

  20. Alcanzando el Éxito a través de la Sinergia entre las Tecnologías de la Información y la Cadena de Valor: El Caso de las PYME en el Cluster Minero de Antofagasta

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    Aurora Del C. Sánchez O.

    2009-05-01

    Full Text Available La literatura sobre innovación y tecnología sugiere que las TI juegan un rol crítico para alcanzar el éxito organizacional. Otros estudios sostienen que el apoyo de las TI a la cadena del valor ha sido de gran importancia para obtener un desarrollo organizacional sostenible. Este artículo proporciona los fundamentos para determinar el nivel de apoyo de las TI al Desarrollo de las PYMEs del sector minero en Antofagasta, Chile. El instrumento de medición fue desarrollado y enviado a 107 PYMEs de la región. Los resultados demuestran que las TI contribuyen a la cadena de valor de las compañías en el nivel de apoyo, básicamente en las actividades de administración y recursos humanos. Además, este estudio sugiere que las compañías que reciben apoyo en más de una actividad primaria de la cadena de valor son escasas, sin embargo una alta proporción de las compañías no usan TI en este nivel.

  1. Dos nuevas especies de cangrejos de agua dulce (Brachyura: Pseudothelphusidae de la Serranía de Los Paraguas, Cordillera Occidental de Colombia

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    Gabriel E Ramos-Tafur

    2006-09-01

    Full Text Available Se describen dos nuevas especies de cangrejos de agua dulce del género Hypolobocera de la Serranía de Los Paraguas, Cordillera Occidental de Colombia. H. solimani n. sp. está estrechamente relacionada con H. alata Campos 1989, pero se puede distinguir de ésta por el margen superior del mero del tercer maxilípedo, el cual es liso; por la forma del ápice del primer gonópodo y la forma del lóbulo interno o papila del canal espermático, la cual es cóncava, levantada y termina bordeada por diminutas papilas o tubérculos redondeados. H. triangula n. sp. es muy similar a H. rotundilobata Rodríguez 1994, pero se diferencia de ésta por el tamaño y la forma del lóbulo lateral, una cresta basal de tubérculos y la superficie apical del gonópodo. Con estas dos nuevas descripciones se incrementa a 20 el número de miembros válidos del género Hypolobocera conocidos del occidente de Colombia o del Chocó biogeográfico.Two new species of fresh water crab (Brachyura: Pseudothelphusidae from Serranía de Los Paraguas, Cordillera Occidental, Colombia. Two new species of freshwater crabs of the genus Hypolobocera from Serranía de Los Paraguas, Cordillera Occidental, Colombia, are described. Hypolobocera solimani n. sp. is closely related to H. alata Campos 1989, but can be distinguished from it by smooth upper margin of third maxilliped merus, the size and shape of apex of first gonopod, and the internal lobe or papilla of spermatic channel, which is concave, raised, with ends with minute papillae or rounded tubercles. Hypolobocera triangula n. sp. is very similar to H. rotundilobata Rodríguez 1994, but differs from it by the shape and size of the lateral lobe, an oblique basal ridge of tubercles and by the apex of first gonopod. With the two new species, the total number of valid members of the genus Hypolobocera known from western Colombia or biogeographic Chocó is 20. Rev. Biol. Trop. 54 (3: 1047-1056. Epub 2006 Sept. 29.

  2. Reducing risks from hazardous glacier lakes in the Cordillera Blanca (Peru): Six decades of experience and perspectives for the future

    Science.gov (United States)

    Portocarrero, Cesar; Cochachin, Alejo; Frey, Holger; González, Cesar; Haeberli, Wilfried; Huggel, Christian

    2016-04-01

    Outbursts from glacier lakes at various spatial and temporal scales have had marked geomorphological effects in many mountain ranges. In many glacierized Andean mountain regions substrates of human settlements made out of flood and debris-flow deposits are testimonies of such events. Examples in the Cordillera Blanca, Peru, are the towns of Caraz, Carhuaz or parts of Huaraz. Continued glacier shrinking since the end of the Little Ice Age caused the formation or enlargement of numerous lakes. The outburst of Laguna Palcacocha, destroying the centre of Huaraz and causing more than 1800 losses of life in December 1941, marked the beginning of systematic risk reduction work in Peru. Corresponding efforts included glacier and lake inventories, hazard assessments, definition of high-risk situations, and completion of engineering work for lake-level lowering in more than 30 cases. The latter comprises outlet reinforcements on morainic dams as well as artificial tunnels in bedrock thresholds. This work has been remarkably efficient as documented in the latest case of the Laguna Huallcacocha (Carhuaz-Ancash), where the earlier made installations withstood the erosive power of an impact wave from an ice avalanche in 2015. In the case of the Laguna 513, the impact wave and far-reaching flood caused by a rock/ice avalanche from Nevado Hualcán in April 2010 showed that the risk had been essentially reduced by the preventive lake-level lowering in the early 1990s but not to zero. Risk assessments, planning, construction and non-structural risk reduction efforts continue. Work is in progress to increase the safety of Laguna Palcacocha where extensive assessments and model calculations had been carried out. Risks related to rock/ice avalanches into lakes from steep icy slopes and related to de-buttressing processes as well as long-term permafrost degradation increases. Based on morphological indications and numerical modelling (GlabTop) an inventory of possible future lakes

  3. Una nueva especie de rana terrestre del género Pristimantis (Amphibia: Craugastoridae, de la Cordillera de Kutukú, Ecuador

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    Jorge Brito M.

    2013-01-01

    Full Text Available Describimos una especie nueva de mediano tamaño (LRC en la hembra 38.7 mm; en machos de 23.8 a 26.4 mm de rana terrestre del género Pristimantis de los bosques sub-tropicales de la Cordillera de Kutukú, del sureste de Ecuador, a elevaciones de 1581-1820 m. Asignamos a Pristimantis almendariz sp. nov., al subgénero Hypodictyon, serie de especies ridens. La nueva especie difiere de otros miembros de la serie ridens por su patrón distintivo con manchas dorsales, membrana timpánica ausente, presencia de tubérculos cónicos agrandados en el párpado, tubérculo inter-orbital prominente, e iris plateado con reticulaciones negras.

  4. Long-term monitoring of tropical alpine habitat change, Andean anurans, and chytrid fungus in the Cordillera Vilcanota, Peru: Results from a decade of study.

    Science.gov (United States)

    Seimon, Tracie A; Seimon, Anton; Yager, Karina; Reider, Kelsey; Delgado, Amanda; Sowell, Preston; Tupayachi, Alfredo; Konecky, Bronwen; McAloose, Denise; Halloy, Stephan

    2017-03-01

    The Cordillera Vilcanota in southern Peru is the second largest glacierized range in the tropics and home to one of the largest high-alpine lakes, Sibinacocha (4,860 m). Here, Telmatobius marmoratus (marbled water frog), Rhinella spinulosa (Andean toad), and Pleurodema marmoratum (marbled four-eyed frog) have expanded their range vertically within the past century to inhabit newly formed ponds created by ongoing deglaciation. These anuran populations, geographically among the highest (5,200-5,400 m) recorded globally, are being impacted by the chytrid fungus Batrachochytrium dendrobatidis (Bd), and the disease it causes, chytridiomycosis. In this study, we report results from over a decade of monitoring these three anuran species, their habitat, and Bd infection status. Our observations reveal dynamic changes in habitat including ongoing rapid deglaciation (18.4 m/year widening of a corridor between retreating glaciers from 2005 to 2015), new pond formation, changes in vegetation in amphibian habitat, and widespread occurrence of Bd in amphibians in seven sites. Three of these sites have tested positive for Bd over a 9- to 12-year period. In addition, we observed a widespread reduction in T. marmoratus encounters in the Vilcanota in 2008, 2009, and 2012, while encounters increased in 2013 and 2015. Despite the rapid and dynamic changes in habitat under a warming climate, continued presence of Bd in the environment for over a decade, and a reduction in one of three anuran species, we document that these anurans continue to breed and survive in this high Andean environment. High variability in anuran encounters across sites and plasticity in these populations across habitats, sites, and years are all factors that could favor repopulation postdecline. Preserving the connectivity of wetlands in the Cordillera Vilcanota is therefore essential in ensuring that anurans continue to breed and adapt as climate change continues to reshape the environment.

  5. The effects of lateral density gradients, slopes and buoyancy on channel flow: 1D analytical solutions and applications to the SE Canadian Cordillera

    Science.gov (United States)

    Gervais, Félix; Ranalli, Giorgio

    2017-08-01

    We present 1D analytical solutions for channel flow in orogens driven by various types of pressure gradients. Our calculations demonstrate that lateral density gradients in the upper crust, such as would occur across a suture zone separating arc rocks from pericratonic sediments provide a driving force for Poiseuille flow as large as topographic gradients observed in modern mountain belts. For cases for which the gradients are external (topographic and lateral density gradients) and internal (e.g. partial melting of channel material) to the channel, inclination decreases and increases the Poiseuille component of the average flow-velocity within the channel by the cosine and sine of the slope, respectively. The magnitude of the pressure gradient consequent upon the buoyancy generated by partial melting of metapelites in a channel with a 30° slope, such as would occur above an underthrusting basement ramp, is similar to that of topographic or lateral density gradients. Channel flow up a ramp could thus constitute an important exhumation mechanism in large hot orogens. Our calculations indicate that mid-crustal channel flow was a highly likely process in the Late Cretaceous-Paleocene setting of the southeastern Canadian Cordillera. The flow was first driven by the lateral density contrast between pericratonic sediments and the arc-related Intermontane terrane, then by combined effect of topographic gradient and melt-induced buoyancy of the Lower Selkirk Allochthon (part of the Shuswap Complex). Flow up the underthrusting basement ramp resulted in exhumation from mid- to upper-crustal levels. Channel flow then migrated downward to involve basement and overlying cover sequence rocks. Our results indicate that syn-convergent channel flow was a viable and very likely process in the southeastern Canadian Cordillera.

  6. The Taxonomic Status of Mazama bricenii and the Significance of the Táchira Depression for Mammalian Endemism in the Cordillera de Mérida, Venezuela.

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    Eliécer E Gutiérrez

    Full Text Available We studied the taxonomy and biogeography of Mazama bricenii, a brocket deer classified as Vulnerable by the IUCN, drawing on qualitative and quantitative morphology and sequences of the mitochondrial cytochrome-b gene. We used Ecological Niche Modeling (ENM to evaluate the hypothesis that M. bricenii of the Venezuelan Cordillera de Mérida (CM might have become isolated from populations of its putative sister species, Mazama rufina, in the Colombian Cordillera Oriental (CO. This hypothesis assumes that warm, dry climatic conditions in the Táchira Depression were unsuitable for the species. Our analyses did not reveal morphological differences between specimens geographically attributable to M. bricenii and M. rufina, and phylogenetic analyses of molecular data recovered M. bricenii nested within the diversity of M. rufina. These results indicate that M. bricenii should be regarded as a junior synonym of M. rufina. ENM analyses revealed the existence of suitable climatic conditions for M. rufina in the Táchira Depression during the last glacial maximum and even at present, suggesting that gene flow between populations in the CO and CM may have occurred until at least the beginning of the current interglacial period and may continue today. Because this pattern might characterize other mammals currently considered endemic to the CM, we examined which of these species match two criteria that we propose herein to estimate if they can be regarded as endemic to the CM with confidence: (1 that morphological or molecular evidence exists indicating that the putative endemic taxon is distinctive from congeneric populations in the CO; and (2 that the putative endemic taxon is restricted to either cloud forest or páramo, or both. Only Aepeomys reigi, Cryptotis meridensis, and Nasuella meridensis matched both criteria; hence, additional research is necessary to assess the true taxonomic status and distribution of the remaining species thought to be CM

  7. The Taxonomic Status of Mazama bricenii and the Significance of the Táchira Depression for Mammalian Endemism in the Cordillera de Mérida, Venezuela.

    Science.gov (United States)

    Gutiérrez, Eliécer E; Maldonado, Jesús E; Radosavljevic, Aleksandar; Molinari, Jesús; Patterson, Bruce D; Martínez-C, Juan M; Rutter, Amy R; Hawkins, Melissa T R; Garcia, Franger J; Helgen, Kristofer M

    2015-01-01

    We studied the taxonomy and biogeography of Mazama bricenii, a brocket deer classified as Vulnerable by the IUCN, drawing on qualitative and quantitative morphology and sequences of the mitochondrial cytochrome-b gene. We used Ecological Niche Modeling (ENM) to evaluate the hypothesis that M. bricenii of the Venezuelan Cordillera de Mérida (CM) might have become isolated from populations of its putative sister species, Mazama rufina, in the Colombian Cordillera Oriental (CO). This hypothesis assumes that warm, dry climatic conditions in the Táchira Depression were unsuitable for the species. Our analyses did not reveal morphological differences between specimens geographically attributable to M. bricenii and M. rufina, and phylogenetic analyses of molecular data recovered M. bricenii nested within the diversity of M. rufina. These results indicate that M. bricenii should be regarded as a junior synonym of M. rufina. ENM analyses revealed the existence of suitable climatic conditions for M. rufina in the Táchira Depression during the last glacial maximum and even at present, suggesting that gene flow between populations in the CO and CM may have occurred until at least the beginning of the current interglacial period and may continue today. Because this pattern might characterize other mammals currently considered endemic to the CM, we examined which of these species match two criteria that we propose herein to estimate if they can be regarded as endemic to the CM with confidence: (1) that morphological or molecular evidence exists indicating that the putative endemic taxon is distinctive from congeneric populations in the CO; and (2) that the putative endemic taxon is restricted to either cloud forest or páramo, or both. Only Aepeomys reigi, Cryptotis meridensis, and Nasuella meridensis matched both criteria; hence, additional research is necessary to assess the true taxonomic status and distribution of the remaining species thought to be CM endemics.

  8. The role of western Mediterranea tectonic evolution in the geometry of a karstic domain in the Betic Cordilleras (Sierra Gorda, Spain): Importance of a tardy extensional regime

    Science.gov (United States)

    Pistre, Séverin; Lopez-Chicano, Manuel; Pulido-Bosch, Antonio; Drogue, Claude

    1999-01-01

    Located in the central part of the Betic Cordilleras, the large carbonate Sierra Gorda Massif provides an example of a west-Mediterranean karstic aquifer. In spite of a complex polyphased tectonic history, the fracturing presents, from aerial views and at outcrop scale a quite organised geometry. Four fracture directions are found over the massif: N000-010, N050-070, N090-100 and N140-170. The statistical and geostatistical approach allows the characteristics (lengths, orientations) and the spatial structure for each fracture set to be determined. The NOOO-010 and N140-170 sets are grouped in packets whereas the two other sets are grouped in bands. The microtectonic study describes the evolution of the massif in the geodynamic context of this part of Mediterranea, distinguishing three recent stages of brittle tectonic activity in the massif: a WNW-ESE Middle Miocene compression, then a NNW-SSE to NW-SE compression with a poorly wrenching regime, and finally a probably pre-Quaternary N-S radial distension. This last stage is essential for the karstification of the massif and groundwater circulation. From the combined analysis of fracture network geometry and palaeostresses a multiple porosity model in agreement with hydrological observations made inside the massif can be proposed: in particular, the hectometric N090-100 (and N050-070) fractures which are essential for the network connectivity, and have a major drainage role at aquifer scale, while the N000-010 and N140-170 ones have a more local drainage role. This extensive tardy regime, which is for the first time described separately from the internal zones of the Cordilleras, must be considered as a significant phenomenon on a regional scale, and henceforth integrated in future geodynamic schemes of this part of Mediterranea.

  9. Spatiotemporal variability and differentiation between anthropogenic and natural contamination of heavy metals of surface water: a case study in the Cordillera Blanca, Peru

    Science.gov (United States)

    Guittard, A.; Baraer, M.; McKenzie, J. M.; Mark, B. G.; Fernandez, A.; Walsh, E.; Santos Perez, A.

    2015-12-01

    The Rio Santa, Peru, drains the western slopes of the glacierized Cordillera Blanca and provides water resources at almost all levels of the watershed. As it flows away from the valleys of the Cordillera Blanca, the Rio Santa takes out pollution from numerous sources, including acid mine drainage and natural sulfide oxidation by-products. The Rio Santa dry season discharge decline that is projected to be a consequence of glaciers retreat will probably have implications for the evolution of water pollution. This threat makes the characterization of the actual contamination mechanisms of primary importance. The present study focuses, first, on the spatiotemporal variability of heavy metal contamination across the entire Rio Santa Watershed and secondly on differentiating anthropogenic and natural contaminated sites. First, a macroscale sampling has been done during the summer 2013 to provide an overview of the contamination by trace metal, in water, suspended sediments and riverbed sediments. In addition, 30 water samples were taken from a point next to the city of Huaraz at a frequency of once every 2 weeks and analyzed for trace metals. Secondly, in order to identify hydrochemical contaminant origin dependant signatures in the Rio Santa watershed, 5 areas of known contamination origins were sampled during the summer 2014.Spatially speaking, we observed that most pollution is located in the south of the watershed, and that a large part of the arsenic that reaches the Santa in an aqueous phase does not make it to the outlet but remains trapped in the riverbed. Annual variation in water shows a very unusual fluctuation in Mn compare to other trace metal which are relatively stable. By differencing anthropogenic and natural sites and by considering glaciers melt and decrease water in future what would be the impact of the part of natural contaminated sites versus anthropogenic, mining and cities, on the water quality? Preliminary results show that anthropogenic sites

  10. Depositación atmosférica de nitrógeno en un transecto valle longitudinal-cordillera de Los Andes, centro-sur de Chile Atmospheric deposition of nitrogen in a transect from the Central Valley to Cordillera de Los Andes, south-central Chile

    Directory of Open Access Journals (Sweden)

    CARLOS E. OYARZÚN

    2002-03-01

    Full Text Available El aumento de las actividades agrícolas y ganaderas en el centro-sur de Chile puede producir elevadas emisiones de nitrógeno hacia la atmósfera (mayormente NH3. El amoniaco es transportado por corrientes de aire y depositado en el suelo y vegetación. El presente estudio evalúa la depositación atmosférica de compuestos nitrogenados (NO3- y NH4+ en la química de las precipitaciones en un transecto altitudinal de 66 km, desde los alrededores de la ciudad de Osorno (40º 35' S, 72º 57' O, 55 m de altitud hasta la cordillera de Los Andes, Parque Nacional Puyehue (40º 46' S, 72º 11' O, 1.120 m de altitud. En siete sitios, durante el período anual junio-1999 hasta mayo-2000, se registró la precipitación y mensualmente se colectaron muestras de agua para determinar: pH, conductividad y las concentraciones de NO3- y NH4+. La precipitación anual se incrementó desde 1.103 mm en la zona de Osorno hasta 6.799 mm en el sector Antillanca, Parque Nacional Puyehue. Los valores promedio anual del pH registraron escasa variación desde 6,3 en el valle central hasta 5,8 en la cordillera de Los Andes. La conductividad presentó los máximos valores en la proximidad de Osorno (22,9 myS cm-1 para descender a través del transecto en zonas intermedias y alcanzar en la Cordillera de los Andes un valor de 11,3 myS cm-1. Las concentraciones promedio de NO3-Nen la lluvia fluctuaron entre 52,3 myg L-1 en la zona agrícola-ganadera y 6,9 myg L-1 en los bosques del Parque Nacional Puyehue. Las concentraciones de NH4-N variaron entre 699,4 myg L-1 en el sector de Osorno y 37,8 myL-1 en la cordillera de Los Andes. Los valores de N-inorgánico poseen una marcada tendencia estacional en el sector agrícola, con valores máximos en primavera-verano y los mínimos en invierno. Las tasas anuales de depositación atmosférica de NO3-N fluctuaron entre 0,53 y 0,57 kg ha-1 año-1 y las de NH4-N fueron entre 6,4 y 2,8 kg ha-1 año-1 para los sitios agrícola-ganaderos de

  11. Recuperación de la biomasa mediante la sucesión secundaria, Cordillera Central de los Andes, Colombia

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    Jorge Ignacio del Valle

    2011-09-01

    Full Text Available En bosques secundarios premontanos tropicales es escasa la información sobre el tiempo requerido para recuperar la biomasa aérea y subterránea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubrían estadios serales de 3 a 36 años y estimamos la biomasa de las plantas y de las raíces gruesas con ecuaciones locales. Así como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. También se calculó la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa aérea viva por hectárea (Bav y la de las raíces gruesas por hectárea (Brg. Modelamos la Bav y Brg en función de la edad mediante la ecuación de von Bertalanfy con asíntotas de 247t/ha (Bav y 66t/ha (Brg resultantes de la medición de 33 parcelas de 0.1ha en los bosques primarios. Con la razón Brg/Bav=f(t estimamos 87 años para que los bosques secundarios recuperen la Bav existente en los primarios y 217 años para recuperar la Brg. La tasa máxima de crecimiento instantáneo de la Bav fue 6.95t/ha/año a los 10 años y la tasa media máxima de crecimiento 6.26t/ha/año a los 17 años. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanzó 4.57t/ha/año y la relativa 10% anual. La razón Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 años (25%, luego disminuye hasta 25 años (18% para luego incrementar hasta 26.7Biomass recovery through secondary succession in the Cordillera Central de los Andes, Colombia. Estimations on biomass recovery rates by secondary tropical forests are needed to understand the complex tropical succession, and their importance on CO2 capture, to offset the warming of the planet. We conducted the study in the Porce River Canyon between 550 and 1 700m.a.s.l. covering tropical and premontane moist belts. We established 33 temporary plots of 50mx20m in secondary

  12. Observaciones fitogeográficas en el páramo de la cordillera oriental del Ecuador

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    1983-01-01

    Full Text Available Dans ce travail, on donne un aperçu général des caractères phytogéographiques de la cordillère orientale de l'Equateur et de l'écologie du type végétal connu comme 'el páramo'. L'absence d'études botaniques et de mesures climatiques empêché pour le moment de présenter des évaluations précises concernant les relations entre les plantes et le haut milieu andin. Mais on peut néanmoins présenter les résultats des études des étages andins des volcans Cayambe, Antisana et Cotopaxi dans la chaîne orientale du pays, où la végétation du páramo montre une grande variété de communautés végétales suivant les conditions écologiques. Le niveau de la limite des neiges permanentes détermine souvent l'amplitude et la variété phytogéographique du páramo de plus, la grande humidité due à des précipitations annuelles dépassant 1000 mm constitue le facteur déterminant pour l'écologie des hautes Andes. La végétation la plus typique sur l'étage andin est la formation de graminées en touffes - 'le pajonal' - à l'intérieur duquel on trouve des communautés végétales spécialisées, parfois mélangées avec des arbres et arbustes. La présence de bétail et les incendies des graminées constituent aujourd'hui les éléments biotiques les plus constants jouant sur la stabilité de la végétation naturelle du páramo équatorien. Aussi, dans l'environnement du páramo, on assiste depuis longtemps à une puissante influence anthropique sur la végétation, s'exerçant même sur le volcan Cotopaxi qui appartient à la zone du parc national. En este trabajo, se da un sobrevuelo general de los caracteres fitogeográficos de la cordillera oriental del Ecuador y de la ecología del tipo vegetal conocido como 'el páramo'. La ausencia de estudios botánicos y de medidas climáticas impide por el momento presentar evaluaciones precisas con respecto a las relaciones entre las plantas y el alto medio andino. Sin embargo, se puede

  13. Guión de la excursión a la Cordillera Ibérica de la asignatura de Geología Histórica y Regional

    OpenAIRE

    Tent Manclús, José Enrique; Giannetti, Alice; Baeza Carratalá, José Francisco; Yébenes Simón, Alfonso

    2012-01-01

    Esta guía surge como documento complementario al campamento de prácticas de campo de la asignatura de Geología Histórica y Regional del Grado de Geología de la Universidad de Alicante. El objetivo principal de este campamento es el conocimiento de los materiales sedimentarios del Paleozoico, Triásico y Jurásico de la Cordillera Ibérica.

  14. Algunos aspectos de la estructura de la Zona Subbética (Cordilleras Béticas. España meridional

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    Hermes, Jacobus J.

    1985-08-01

    Full Text Available Analysis of sedimentation and tectonics of the Subbetic zone of the Betic Cordilleras leads to the conclusion that sedimentation and subsequent deformation are largely governed by a Wilson cycle (Wilson, 1966, 1968 that began the opening of the Tethyan rift in the Pangaea continent during the Pliensbachian, 180 Ma ago. The resulting ocean began to close again in the Cretaceous, a process that led to a collision between Iberia and African elements in the Burdigalian, which was followed by strike-slip movement along a shear zone between the two plates which continues to this day. It is argued that the collision led to general uplift of the Subbetic zone as shown by the termination of deep water pelagic and hemipelagic sedimentation in the entire zone, and that the subsequent strike-slip movements along a system of anastomosing faults loo to very intense deformation localized along separate fault zones, and to the opening of pull-apart basins with characteristic sedimentation sequences.

    El análisis de la sedimentación y la tectónica de la Zona Subbética (Cordilleras Béticas conduce a la conclusión de que la sedimentación y la deformación posterior han sido ampliamente determinadas por un ciclo de Wilson (Wilson, 1966, 1968; Mitchell y Reading, 1978 que comenzó con la apertura del Tethys en el continente de Pangaea durante el Pliensbaquiense, hace 180 ID. a. El océano resultante empezó a cerrarse de nuevo en el Cretácico. Este proceso condujo a la colisión entre Iberia y elementos africanos en el Burdigaliense y fue seguido por un movimiento de salto en dirección a favor de una zona de cizalla que aún continúa en la actualidad. La colisión provocó el levantamiento general del la Zona Subbética, como lo demuestra el cese de la sedimentación pelágica y hemipelágica profundas por toda ella. Los movimientos subsiguientes de salto en 'dirección a favor de un sistema de fallas anastomosadas produjeron una deformación muy

  15. Using thermodynamic modelling, quartz-in-garnet geobarometry and monazite geochronology to understand Early Jurassic orogenesis in the Northern Canadian Cordillera

    Science.gov (United States)

    Clark, Andy; Gibson, Dan; Ashley, Kyle; Staples, Reid; Israel, Steve

    2017-04-01

    Polydeformed mid-crustal rocks crop out throughout much of the Northern Canadian Cordillera in Yukon, Canada, yet the timing and conditions of deformation and metamorphism are not well constrained in many areas. Regional mapping, in-situ monazite U-Pb geochronology, quartz-in-garnet geobarometry and thermodynamic modelling indicate that parts of southwest Yukon experienced tectonic burial to 25-30 kilometres by 199 Ma. Decompression was accompanied by widespread high-Y monazite growth around 185 Ma. These results highlight the significance of thick-skinned Early Jurassic orogenesis in the Northern Canadian Cordillera. Data obtained using garnet isopleth thermobarometry and pseudosection modelling indicate that garnet grew along a positive P-T gradient, with garnet nucleation at 0.3-0.4 GPa and 500-550°C. Modelling constrains peak metamorphic conditions to 0.6-0.8 GPa and 650°C. Pressure estimates obtained using Raman spectra of quartz inclusions in garnet cores (quartz-in-garnet geobarometry) also suggest that garnet nucleation occurred at pressures of 0.3-0.4 GPa. However, pressures obtained from inclusions outside of garnet cores vary between 0.3 and 0.7 GPa, with some intervals of garnet growth apparently accompanied by a decrease in pressure. Therefore, these data are not consistent with garnet growth along a simple positive P-T gradient, as suggested by thermodynamic modelling. Our results highlight discrepancies between metamorphic conditions obtained using thermodynamic modelling compared with those obtained using quartz-in-garnet geobarometry. This brings into question the accuracy of P-T paths obtained by using techniques, such as pseudosection modelling, which often cannot resolve such paths in detail. Nevertheless, the consistent garnet core pressures obtained in this study suggest that garnet growth initiated at near equilibrium P-T-X conditions. A subsequent departure from equilibrium conditions would explain the discrepancy between thermodynamic

  16. A ~20,000 year history of glacial variability in the tropical Andes recorded in lake sediments from the Cordillera Blanca, Peru

    Science.gov (United States)

    Stansell, N.; Rodbell, D. T.; Moy, C. M.

    2010-12-01

    Pro-glacial lake sediments from the Cordillera Blanca, Peru contain continuous records of climate variability spanning the Last Glacial Maximum to present day. Here we present results from two alpine lake basins in the Queshgue Valley (9.8°S, 77.3°W) that contain high-resolution records of clastic sediment deposition for the last ~20,000 years. Radiocarbon-dated sediment cores were scanned at 0.5 to 1.0 cm resolution using a profiling x-ray fluorescence scanner for major and minor element distributions. In addition, we measured down-core variations in magnetic susceptibility, organic carbon, biogenic silica and calcium carbonate. Samples of bedrock and sediments from glacial moraines in the Queshgue watershed were analyzed using an ICP-MS in order to fingerprint and trace the source of glacial sediments deposited in the lakes. The bedrock is dominated by a combination of granodiorite with high Sr concentrations and meta-sedimentary rocks with high Zr values. Because the glacial sediments proximal to the modern glacier terminus are composed mostly of the granodiorite end-member, we interpret changes in Sr and clastic sediment concentrations in the lake sediment profiles as proxies for past glacial variability. Preliminary results indicate that glaciers retreated soon after ~14,500 cal yr BP and remained less extensive during the remaining late Glacial Stage and early Holocene. Gradually increasing clastic sediments through the middle and late Holocene indicate that glaciers became progressively larger, or more erosive towards present day. However, this overall Holocene trend of increasing glacier extent was interrupted by multiple periods of centennial- to millennial-scale ice margin retreat. For example, relative peaks in clastic sediments occurred from ~14,500 to 6000, 5600 to 5000, 4600 to 4200, 3600 to 3200, 2800 to 2700, 2400 to 2200, 1750 to 1550, 1100 to 900 cal yr BP, and during the Little Ice Age (~700 to 50 cal yr BP), while periods of low clastic

  17. Efecto del Compost de Biosólidos en la producción de plantines de Austrocedrus Chilensis (ciprés de la cordillera) Effect of Biosolids Compost on seedling production of Austrocedrus Chilensis (ciprés de la cordillera)

    OpenAIRE

    Gustavo Basil; María Julia Mazzarino; Lucía Roselli; Federico Letourneau

    2009-01-01

    La utilización de compost de residuos urbanos como sustrato en contenedores es una alternativa interesante a nivel económico y ambiental, dado que reduciría el uso de turba y «tierra negra» en la producción de plantines, y la disposición de residuos en vertederos. En el presente trabajo se estudió el efecto de 0, 30 y 50% de compost de biosólidos en el crecimiento inicial (primer año) de ciprés de la cordillera, y el efecto durante los dos años siguientes de un tratamiento único con 50% de co...

  18. Geochemistry and tectonic setting of the «ophites» from the external zones ofthe Betic Cordilleras (S. Spain

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    Aguirre, L.

    1997-08-01

    Full Text Available Mesozoic basic magmatism in the External Zones of the Betic Cordilleras (S. Spain is represented by small tectonic bodies (ophites in Triassic formations, and submarine flows with abundant pillow-lavas interbedded with Jurassic sediments. Both basic igneous manifestations suffered very low- to low-grade metamorphism, more intense in the case of the ophites. Two types of ophites are distinguished on the basis of their primary mineralogy. In the first type, orthopyroxene is present in the less differentiated products. Clinopyroxene and Ca-plagioclase are the main primary phases and quartz appears in the more evolved rocks. In the second type, olivine is present in the less differentiated products. Ti-rich augite and Ca-plagioclase are also important primary minerals, but quartz is absent. Whole-rock chemistry (major and trace elements, including REE also allows us to discriminate between these two groups. The first group has higher SiO2, and lower TiO2, P2O5 and lower Na2O/K2O ratios than the second. Normative quartz is almost invariably present in this first group, whereas normative nepheline (lower than 5% is characteristic of the second group. Both groups are Sr, K, Ba, Rb, Th, Nb and Ce enriched with respect to normal MORB, but the first group has higher K, Rb, Ba, Th and lower Nb, Ce contents than the alkaline group. Nb/Y and Ti/V ratios are also different and show a tholeiitic affinity for the first group and transitional to alkaline for the second. Chondrite-normalised REE patterns in both groups are similar and characterized by LREE enrichment with respect to HREE. LREE/HREE ratios are, however, slightly higher in the transitional to alkaline group. Various discriminant tectonic diagrams indicate a continental intraplate setting for both ophite groups. This magmatism is related to the first extensional period of the Betic Cordilleras, during the Triassic-Jurassic. Geochemical differences between the two groups could evidence different

  19. Late Palaeozoic heavy mineral and clast modes from the Betic Cordillera (southern Spain): transition from a passive to an active continental margin

    Science.gov (United States)

    Herbig, Hans-Georg; Stattegger, Karl

    1989-06-01

    Silurian to Late Carboniferous sediments constitute most of the uppermost nappe (Malaguides) in the internal zone of the Betic Cordillera. The sediments represent continuous deep-water environments dominated by flysch deposition. Repeated changes between acid plutonic/recycled cratonic and metamorphic sedimentary input are evidenced by heavy mineral spectra and psephitic clast modes of the Devonian-Carboniferous formations. Oscillations and amplitudes, especially of metamorphic detrital influx, become more frequent and larger, respectively, near the Variscan disconformity. Permo-Triassic redbeds are clearly post-orogenic sediments according to lithofacies and heavy mineral content. The joint development of lithofacies, clast modes and heavy mineral spectra demonstrates the transition from a passive to an active continental margin during the Palaeozoic: the Silurian-Devonian sediments of the Malaguide realm were deposited during a divergent cratonic stage north of the Betico-Rifean block, which is a detached sliver of the African plate. The Viséan-Upper Carboniferous formations record the collision orogenic stage between the Betico-Rifean block and the southern margin of the Southern Europe plate. The collision processes induced strong uplift and erosion of successively shallowing carbonate shelf realms and the connected crystalline, mostly metamorphic hinterland. The source area was the Betico-Rifean block south of the Malaguide basin. Palaeogeographic connections of the Malaguides, especially with Minorca (Baleares), are shortly discussed.

  20. Estrategias de talla en Cueva Corazón (Mave, Palencia. Un yacimiento del Musteriense Antiguo en las estribaciones meridionales de la Cordillera Cantábrica

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    Sánchez Yustos, Policarpo

    2011-06-01

    Full Text Available This article presents a study of the lithic record recently retrieved from Cueva Corazón in the context of a new research projects initiated in 2005. We have detected a variety of long, albeit highly fragmented, operational sequences. A remarkable technological standardization has also been observed, a trait clearly related to the use of good quality raw materials. These observations allow the inference of a complex web of territorial and social interactions. Moreover, Cueva Corazón, due to its chronology and strategic location, can become a future reference point for the study of the Early Mousterian on both sides of the Cantabrian Range.

    Este artículo estudia el registro lítico de Cueva Corazón en el marco de un proyecto de investigación iniciado en 2005. Hemos detectado una variedad y alargamiento de cadenas operativas líticas, frecuentemente fragmentadas, y una elevada estandarización tecnológica asociada a elaboradas estrategias de captación de materias primas de buena calidad. Este hecho permite inferir una complejidad de las redes territoriales y sociales. Por otro lado, su cronología y posición estratégica hacen de este enclave un lugar excepcional para conocer el Musteriense antiguo en ambos lados de la cordillera cantábrica.

  1. A NEW SPECIES OF CASTILLEJA (OROBANCHACEAE FROM THE PÁRAMOS OF THE COLOMBIAN EASTERN CORDILLERA, WITH COMMENTS ON ITS ASSOCIATION WITH PLANTAGO RIGIDA (PLANTAGINACEAE

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    FAVIO GONZÁLEZ

    2013-12-01

    Full Text Available Castilleja paramensis F. González & Pabón-Mora, a perennial species of small herbs from páramos of Santander, Boyacá and Cundinamarca, in the Colombian Eastern Cordillera, is described and fully illustrated by photographs of the type collection. The new species is morphologically and ecologically similar to C. nubigena, C. pumila, and C. virgata, three perennial high Andean species from Ecuador, Peru and northern Chile and Argentina. C. paramensis is clearly distinguished from its relatives by the small size of the individuals, the broadly elliptic leaves and bracts (which are entire to slightly trilobed, the short (< 1 mm pedicel, the small size (0.8- 1.15 cm long of the flowers, the not inflated calyx with the distal half bright yellow, the corolla often included to slightly exserted from the calyx, and the included style and stigma. The included corolla, stamens, styles and stigmas in C. paramensis strongly suggest the occurrence of cleistogamy. The new species often grows as a root hemiparasite of Plantago rigida.

  2. Time-scales of assembly and thermal history of a composite felsic pluton: constraints from the Emerald Lake area, northern Canadian Cordillera, Yukon

    Science.gov (United States)

    Coulson, Ian M.; Villeneuve, Mike E.; Dipple, Gregory M.; Duncan, Robert A.; Russell, James K.; Mortensen, James K.

    2002-05-01

    Knowledge of the time-scales of emplacement and thermal history during assembly of composite felsic plutons in the shallow crust are critical to deciphering the processes of crustal growth and magma chamber development. Detailed petrological and chemical study of the mid-Cretaceous, composite Emerald Lake pluton, from the northern Canadian Cordillera, Yukon Territory, coupled with U-Pb and 40Ar/ 39Ar geochronology, indicates that this pluton was intruded as a series of magmatic pulses. Intrusion of these pulses produced a strong petrological zonation from augite syenite, hornblende quartz syenite and monzonite, to biotite granite. Our data further indicate that multiple phases were emplaced and cooled to below the mineral closure temperatures over a time-scale on the order of the resolution of the 40Ar/ 39Ar technique (˜1 Myr), and that emplacement occurred at 94.3 Ma. Simple thermal modelling and heat conduction calculations were used to further constrain the temporal relationships within the intrusion. These calculations are consistent with the geochronology and show that emplacement and cooling were complete in less than 100 kyr and probably 70±5 kyr. These results demonstrate that production, transport and emplacement of the different phases of the Emerald Lake pluton occurred essentially simultaneously, and that these processes must also have been closely related in time and space. By analogy, these results provide insights into the assembly and petrogenesis of other complex intrusions and ultimately lead to an understanding of the processes involved in crustal development.

  3. Characterizing contributions of glacier melt and groundwater during the dry season in a poorly gauged catchment of the Cordillera Blanca (Peru

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    M. Baraer

    2009-10-01

    Full Text Available The retreat of glaciers in the tropics will have a significant impact on water resources. In order to overcome limitations with discontinuous to nonexistent hydrologic measurements in remote mountain watersheds, a hydrochemical and isotopic mass balance model is used to identify and characterize dry season water origins at the glacier fed Querococha basin located in southern Cordillera Blanca, Peru. Dry season water samples, collected intermittently between 1998 and 2007, were analyzed for major ions and the stable isotopes of water (δ18O and δ2H. The hydrochemical and isotopic data are analysed using conservative characteristics of selected tracers and relative contributions are calculated based on pre-identified contributing sources at mixing points sampled across the basin. The results show that during the dry-season, groundwater is the largest contributor to basin outflow and that the flux of groundwater is temporally variable. The groundwater contribution significantly correlates (P-value=0.004 to 0.044 to the antecedent precipitation regime at 3 and 18–36 months. Assuming this indicates a maximum of 4 years of precipitation accumulation in groundwater reserves, the Querococha watershed outflows are potentially vulnerable to multi-year droughts and climate related changes in the precipitation regime. The results show that the use of hydrochemical and isotopic data can contribute to hydrologic studies in remote, data poor regions, and that groundwater contribution to tropical proglacial hydrologic systems is a critical component of dry season discharge.

  4. Evidence of Early to Middle Ordovician arc volcanism in the Cordillera Oriental and Altiplano of southern Peru, Ollantaytambo Formation and Umachiri beds

    Science.gov (United States)

    Bahlburg, Heinrich; Carlotto, Victor; Cárdenas, José

    2006-11-01

    Volcanic rocks of intermediate to predominantly mafic composition are exposed in the Cordillera Oriental and Altiplano of southern Peru in two localities: (1) the Ollantaytambo Formation, which crops out near Cusco, and (2) the Umachiri beds in the Departamento de Puno. The most notable unit in the Ollantaytambo Formation is an approximately 100 m thick succession of lapilli tuffs that originated by hydroclastic fragmentation. These volcanic rocks are of calc-alkaline basaltic to andesitic composition. The tuffs are overlain by fine-grained volcaniclastic sandstones and shales, which grade into quartz-rich turbidites. The Umachiri beds consist of monomict lapilli tuffs with varying lapilli abundance and size, formed by hydroclastic fragmentation, and volcaniclastic sandstones. The rocks have a uniform basaltic andesite composition and tholeiitic affinity. Chondrite-normalized element patterns of both volcanigenic units show a moderate enrichment of LREE and a weak negative Eu anomaly. Pronounced negative Nb and Ta anomalies indicate magma evolution in an arc environment. In contrast, the overlying epiclastic sandstones and shales in the Ollantaytambo Formation reflect upper crustal sources. Our data indicate that the deposition of the lapilli tuffs of the Ollantaytambo Formation and Umachiri beds likely was connected to the westward-lying Ordovician magmatic arc on the Arequipa Massif. If the Ordovician active margin in southern Peru had the same east-dipping subduction polarity as the active Gondwana margin in Argentina and Chile, the sedimentary basin in which the Ollantaytambo Formation and Umachiri beds were deposited was in a backarc position.

  5. Rocas volcanoclasticas submarinas de edad Burdigaliense inferior en el sector del Mencal (Zona Subbetica, Cordillera Bética central. Contexto sedimentario y tectónico

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    Soria, J. M.

    1994-08-01

    Full Text Available This paper discuss the petrologic features of volcaniclastic rocks and its geodynamic implications. This rocks are included in the pelagic marine sediments of lower Burdigalian from the Río Fardes region (Subbetic Zone, Betic Cordillera. There are two different kinds of volcaniclastic rocks: vitric and feldspathic sandstones, and vitric siltstones, both of them from fragmental volcanic emissions of a calc-alkaline rhyodacitic magma. In these rocks there are planktonic Foraminifera that indicate volcanism occurring in a submarine environment. The emission focus is placed close to the present-day location of these rocks, due to low dispersion of the pyroclastic fragments into the pelagic marine deposits. During lower Burdigalian several N70ºE strike-slip faults was working simultanously with the pelagic marine sedimentation. In this paper it is assumed that these faults are connected with the volcanic activity. During the lower Miocene the orogenic deformation of the Sudiberian PaJeomargin (External Betic Zones are related to fracturarion and volcanism, in coincidence with a major tectonic event, best known as Burdigalian Paroxysm (Hermes, 1985.El presente trabajo se centra en la caracterización petrológica y significado geodinámico de las rocas volcanoclásticas que aparecen en los materiales marinos pelágicos del Burdigaliense inferior que afloran en el sector del Mencal (Zona Subbética del tercio central de la Cordillera Bética. Se diferencian dos tipos de rocas volcanoclásticas: areniscas vítricas y feldespáticas y limolitas vítricas, ambas procedentes de emisiones volcánicas fragmentales de un magma calcoalcalino-riodacítico. En los dos tipos se encuentran foraminíferos planctónicos, hecho que indica que el volcanismo se produjo en condiciones submarinas. La escasa dispersión de los piroclastos dentro de los depósitos marinos pelágicos permite deducir que el foco de emisión volcánica se localizó muy próximo al lugar

  6. Present and future water resources supply and demand in the Central Andes of Peru: a comprehensive review with focus on the Cordillera Vilcanota

    Science.gov (United States)

    Drenkhan, Fabian; Huggel, Christian; Salzmann, Nadine; Giráldez, Claudia; Suarez, Wilson; Rohrer, Mario; Molina, Edwin; Montoya, Nilton; Miñan, Fiorella

    2014-05-01

    Glaciers have been an important element of Andean societies and livelihoods as direct freshwater supply for agriculture irrigation, hydropower generation and mining activities. Peru's mainly remotely living population in the Central Andes has to cope with a strong seasonal variation of precipitations and river runoff interannually superimposed by El Niño impacts. Direct glacier and lake water discharge thus constitute a vital continuous water supply and represent a regulating buffer as far as hydrological variability is concerned. This crucial buffer effect is gradually altered by accelerated glacier retreat which leads most likely to an increase of annual river runoff variability. Furthermore, a near-future crossing of the 'peak water' is expected, from where on prior enhanced streamflow decreases and levels out towards a new still unknown minimum discharge. Consequently, a sustainable future water supply especially during low-level runoff dry season might not be guaranteed whereas Peru's water demand increases significantly. Here we present a comprehensive review, the current conditions and perspectives for water resources in the Cusco area with focus on the Vilcanota River, Cordillera Vilcanota, Southern Peru. With 279 km2 the Cordillera Vilcanota represents the second largest glacierized mountain range of the tropics worldwide. Especially as of the second half of the 1980s, it has been strongly affected by massive ice loss with around 30% glacier area decline until present. Furthermore, glacier vanishing triggers the formation of new lakes and increase of lake levels and therefore constitutes determining hazardous drivers for mass movements related to deglaciation effects. The Vilcanota River still lacks more profound hydrological studies. It is likely that its peak water has already been or might be crossed in near-future. This has strong implications for the still at 0.9% (2.2%) annually growing population of the Cusco department (Cusco city). People mostly

  7. Registro histórico de Gastrotheca ovifera (Anura: Hemiphractidae: evidencias de disminución en selvas nubladas de la Cordillera de la Costa venezolana

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    Javier Valera-Leal

    2011-03-01

    Full Text Available Gastrotheca ovifera es una rana marsupial que habita en el dosel arbóreo de bosques nublados y ribereños del Tramo Occidental y Ramal Litoral de La Cordillera de la Costa venezolana (CCV entre 820-2 000m de altitud. De acuerdo con la Lista Roja de la UCN se encuentra En Peligro (EN y su evaluación fue realizada de acuerdo a apreciaciones anecdóticas, por lo que su situación de amenaza no ha sido comprobada por muestreos sistemáticos. Con el objetivo de estudiar el estado de las poblaciones de la especie en el Parque Nacional Henri Pittier (PNHP en el Ramal Litoral de la CCV, realizamos una revisión histórica en museos nacionales y extranjeros y encontramos que la especie fue registrada en 1996 por última vez en el PNHP. Acumulamos 646 horas/persona de muestreo sistemático en localidades históricas y adicionales de la especie en el parque durante los años 2006 y 2007 y no obtuvimos registro de la especie. Adicionalmente, realizamos asociaciones entre datos promedios de precipitación anual y el registro histórico de la especie durante el periodo 1941-1997 (r s=- 0.054, p=0.820, n=19. Discutimos sobre su estado de conservación con base a la distribución, fluctuación y cambios poblacionales de la especieHistoric record of Gastrotheca ovifera (Anura: Hemiphractidae: decline evidence in Venezuelan coastal cloud forests. G. ovifera is a marsupial frog of the cloud and riparian forest from Western and Litoral sections of the Venezuelan Cordillera de la Costa (820-2 000m. This amphibian is considered as an endangered species by the IUCN Species Red List, due to its population decline in pristine and well preserved environments. This conservation status is based on anecdotic interpretations. We collected disperse data from museum records (national and international and explored the possible association between collection records and precipitation data available for the Henri Pittier National Park (PNHP. Likewise, we carried out a

  8. Los materiales hercínicos de la cordillera ibérica en el contexto del macizo ibérico

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    Liñán, E.

    1988-12-01

    Full Text Available The discontinuity observed between the paleozoic outcrops of the Iberian Mountains and the ones of the Iberian Massif, has been the greatest incovenient to include those ones in a general Hercynian Iberian model. Two hypothesis have been proposed to the respect. One initial hypothesis postulates the inclusion of the Iberian Mountains paleozoic racks in the West Asturian-Leonese Zone (Lotze, 1961; Julivert et al., 1974. Other one postulates a double inelusion: the occidental part of the Iberian Chaines into the West Asturian-Leonese Zone and the oriental part of the Iberian Chaines into the Cantabrian Zona (Liñán, 1983. In this work new geological data are provided for the geological conexion between Cantabrian Zone and the oriental part of the Iberian Chains; they can be summarised in three points. One of them is referred to the paralellism between the Narcea and Paracuellos antiforms. Those antiforms are divided by a tectonic accident, wich separates different Precambrian sequences. Another point deals with the close relation of the stratigraphical sequences of the Paleozoic racks between the Cantabrian region and Iberian region at both sides of the Narcea and Paracuellos antiforms. the last point refers to the study of small outcrops located in the northwest of the Iberian Chains, that show a probably more similar geological structure to the Cantabrian Zone wich was defined as a fold and thrust belt.La falta de continuidad de los afloramientos paleozoicos de la Cordillera Ibérica con los del Macizo Ibérico han venido constituyendo un serio obstáculo para la inclusión de aquéllos dentro de un esquema general para el hercínico ibérico. Dos hipótesis han sido hasta ahora planteadas: su conexión con la Zona Asturoccidental-Leonesa, o su doble conexión con esta zona y con la zona Cantábrica. En este trabajo se aportan nuevos datos geológicos que son congruentes con la prolongación tanto de la Zona Cantábrica como de la Zona

  9. Registro histórico de Gastrotheca ovifera (Anura: Hemiphractidae: evidencias de disminución en selvas nubladas de la Cordillera de la Costa venezolana

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    Javier Valera-Leal

    2011-03-01

    Full Text Available Gastrotheca ovifera es una rana marsupial que habita en el dosel arbóreo de bosques nublados y ribereños del Tramo Occidental y Ramal Litoral de La Cordillera de la Costa venezolana (CCV entre 820-2 000m de altitud. De acuerdo con la Lista Roja de la UCN se encuentra En Peligro (EN y su evaluación fue realizada de acuerdo a apreciaciones anecdóticas, por lo que su situación de amenaza no ha sido comprobada por muestreos sistemáticos. Con el objetivo de estudiar el estado de las poblaciones de la especie en el Parque Nacional Henri Pittier (PNHP en el Ramal Litoral de la CCV, realizamos una revisión histórica en museos nacionales y extranjeros y encontramos que la especie fue registrada en 1996 por última vez en el PNHP. Acumulamos 646 horas/persona de muestreo sistemático en localidades históricas y adicionales de la especie en el parque durante los años 2006 y 2007 y no obtuvimos registro de la especie. Adicionalmente, realizamos asociaciones entre datos promedios de precipitación anual y el registro histórico de la especie durante el periodo 1941-1997 (r s=- 0.054, p=0.820, n=19. Discutimos sobre su estado de conservación con base a la distribución, fluctuación y cambios poblacionales de la especie

  10. Lake records of Northern Hemisphere South American summer monsoon variability from the Cordillera Oriental, Colombia: Initial results from Lago de Tota and Laguna de Ubaque

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    Escobar, J.; Rudloff, O.; Bird, B. W.

    2013-12-01

    The lack of terrestrial paleoclimate records from the Northern Hemisphere Andes with decadal resolution has meant that our understanding of abrupt South American summer monsoon (SASM) variability during the Holocene is almost exclusively based on data from Southern Hemisphere sites. In order to develop a more integrated and complete picture of the SASM as a system and its response during rapid climate changes, high-resolution paleoclimate records are needed from the Northern Hemisphere Andes. We present initial results from analysis of lake sediment cores that were collected from Lago de Tota (N 5.554, W 72.916) and Laguna de Ubaque (N 4.500, W 73.935) in the Eastern Cordillera of the Colombian Andes. These sediment cores were collected in July 2013 as part on an ongoing paleoclimate research initiative in Colombia. Located in the Boyacá Provence, Lago de Tota is the largest high-altitude lake (3010 masl) in the Northern Hemisphere Andes and the second largest Andean lake in South America. As such, hydrologic changes recorded in the lake's sediment record reflect regional climate responses. Lago de Ubaque (2070 masl) is a small east facing moraine-dammed lake near the capital of Bogotá that contains finely laminated clastic sediments. The initial sedimentological and chronological results demonstrate that Lago de Tota and Laguna de Ubaque have excellent potential for resolving Northern Hemisphere SASM variability at decadal time scales or better. Such records will provide important counterparts to high-resolution paleoclimate records from the Southern Hemisphere Andes.

  11. DIVERSIDAD FLORÍSTICA Y ESTRUCTURA DE REMANENTES DE BOSQUE ANDINO EN LA ZONA DE AMORTIGUACIÓN DEL PARQUE NACIONAL NATURAL LOS NEVADOS, CORDILLERA CENTRAL COLOMBIANA

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    Franco Marcela

    2010-06-01

    Full Text Available Se caracterizó la diversidad, la composición fl orística y la estructura de los bosquesde la Reserva Torre Cuatro, la cual hace parte de la zona amortiguadora del ParqueNacional Natural Los Nevados, Cordillera Central de los Andes colombianos. Losremanentes de bosque se subdividieron en tres zonas de acuerdo a la altitud: baja(2650-2900 m, media (3000-3300 m y alta (3400-3750 m, en cada una de las cualesse muestreó 0.1 ha y se censaron todos los individuos con DAP ≥ 2.5 cm. La riquezade especies encontrada para las tres zonas (62 para la baja, 69 para la media y 48para la baja fue superior al promedio registrado para otros bosques andinos situadosa altitudes similares. En todas las zonas la mayor proporción de individuos tuvieronalturas inferiores a 7.2 m. La composición fl orística y la fi sonomía de los bosquesmuestra que los de las zonas baja y media corresponden a los descritos para la franjaandina propiamente dicha, mientras que los de la alta a la franja alto andina. En todaslas zonas las familias con mayor importancia ecológica fueron Melastomataceae yAsteraceae, pero también se destacaron Cunoniaceae en la baja, Betulaceae en lamedia y Ericaceae en la alta. En todas las zonas unas pocas especies sobresalieron porsu mayor importancia ecológica en la comunidad (IVI; en las zonas baja y media lascinco especies con más IVI acumularon aproximadamente el 30% del mismo, mientrasque en la zona alta cerca del 47%. Las especies con más IVI fueron Weinmanniapubescens (32.7 en la zona baja, Alnus acuminata (29.9 en la media y Tibouchinaandreana (33.4 en la alta.

  12. Flora y vegetación de suelos crioturbados y hábitats asociados en la Cordillera Blanca, Ancash, Perú

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    Asunción Cano

    2011-05-01

    Full Text Available Entre los años 2006 y 2008, se llevaron a cabo estudios florístico y de vegetación de los suelos crioturbados y hábitats asociados en cuatro localidades de la Cordillera Blanca (Ancash, Perú localizadas por encima de los 4500 m. Se realizaron recolectas botánicas además de transectos de intersección-línea, en los cuales se midió el espacio (en cm ocupado por cada especie. Fueron determinadas 136 especies de plantas vasculares, agrupadas en 65 géneros y 26 familias. Las Magnoliópsida (dicotiledóneas fueron las más diversas con 97 especies, seguidas de las Liliópsidas (Monocotiledóneas con 36. La mayor diversidad está concentrada en las familias Asteraceae y Poaceae (40,63%. Los géneros con mayor riqueza de especies fueron Senecio (18 y Calamagrostis (12. Se registraron 76 especies (54,82% en suelos crioturbados y hábitats asociados; mientras que 60 especies (44,11% fueron colectadas en la vegetación adyacente. El 95,56% de las especies reportadas fueron hierbas perennes. Se caracterizaron cuatro tipos de comunidades vegetales: a comunidad de suelos crioturbados propiamente dicha, b comunidad de suelos crioturbados asociada a pajonal, c comunidad de suelos crioturbados asociada a roquedal seco y d comunidad de suelos crioturbados asociadas a roquedal húmedo. Se indícan las especies características de cada comunidad.

  13. A modelling study of the seasonal snowpack energy balance at three sites along the Andes Cordillera. Regional climate and local effects.

    Science.gov (United States)

    McPhee, James; Mengual, Sebastian; MacDonell, Shelley

    2017-04-01

    Seasonal snowpack melt constitutes the main water source for large portions of extratropical South America, including central Chile and Western Argentina. The properties and distribution of snow in the Andes are threatened by rapid climate change, characterised by warming and drying. This study provides a first attempt at detailed description of the energy balance of the seasonal snowpack and its variability along a latitudinal gradient, which is also correlated with an elevation and precipitation gradient, in the Andes Cordillera. The Snowpack model was validated at semi-arid, Mediterranean and temperate humid sites, where meteorological and snowpack properties have been observed since year 2013. Site elevations decrease from north to south, whereas precipitation climatology increases with latitude. Results show that turbulent energy exchange becomes relatively more important in periods of low snow accumulation, with sensible heat fluxes having a greater effect in cooling the snowpack at the high-altitude, low latitude site. Likewise, daily melt-freeze cycles are important in maintaining positive cold contents throughout the accumulation season at this site, and contribute to extending the duration of snow cover despite low accumulation and high radiation loads. In contrast, the southernmost, lowest elevation site shows smaller daily temperature amplitude and a much more preponderant radiation component to the energy balance. This modelling exercise highlights the nonlinearities of snow dynamics at different geographical settings in a sparsely monitored mountain area of the world, as well as the need for further understanding in order to evaluate the sensitivity of snow-dominated watersheds to global warming and climate change.

  14. Las bioconstrucciones de corales y sus facies asociadas durante el Malm en la Cordillera Ibérica Central (provincia de Zaragoza

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    Meléndez, A.

    1987-08-01

    Full Text Available The differents types of bioconstructions and associated facies in the Central Iberian Chain (Higueruelas Formation, Upper Kimmeridgian have been studied. Biohermes of different thickness (decimetric to metric and less lateral continuity are developped, highly colonized by corals, that are associated to oncolitic, bioclastic and oolitic of high energy facies, in marginal areas, near the litoral developpment. At the same time takes place an important set up of mud mounds, with a small coral colonisation, in protected arcas in a inner shelf, or in outer areas, where the action of the waves is not so effective. The environment protection is been generated in some places due to the appearance of oolitic barrier islands.Se estudian los diferentes tipos de bioconstrucciones de corales, y sus facies asociadas, presentes en el sector central de la rama aragonesa de la Cordillera Ibérica, en la Formación Higueruelas (Kimmeridgiense superior. Se desarrollan biohermos de potencias métricas a decimétricas y escasa continuidad lateral, intensamente colonizados por corales coloniales, que se encuentran asociados a facies oncolíticas, bioclásticas y oolíticas de alta energía en zonas marginales, próximas al desarrollo litoral. Al mismo tiempo tiene lugar una importante instalación de mud mounds, con escasa colonización de corales, en zonas protegidas dentro de la plataforma interna o en zonas más externas, donde la acción del oleaje no es efectiva. La protección del medio viene condicionada en algunos puntos por la aparición de islas barrera oolíticas.

  15. Late Cretaceous-Cenozoic Evolution of the Central Andean Foreland Basin System in the Eastern Cordillera to Subandean Zone, Southern Bolivia

    Science.gov (United States)

    Calle, A.; Horton, B. K.; Anderson, R. B.; Long, S. P.

    2015-12-01

    Evaluation of foreland basin deposystems and provenance across southern Bolivia reveals punctuated growth of the central Andean orogenic wedge. New and published sedimentology, provenance data, stratigraphy, subcrop mapping, and apatite (U-Th)/He thermochronometry along two transects (19.5, 21°S) from the easternmost Eastern Cordillera (EC) to the western Subandean Zone (SAZ) shed light on Late Cretaceous-Miocene thrust belt and foreland basin dynamics. Sediment dispersal patterns are constrained by paleocurrents, detrital zircon U-Pb geochronology, sandstone petrography, and conglomerate clast compositions. Spatial and temporal changes in the Andean thrust belt are recorded in asymmetric foreland basin thicknesses, facies distributions, and provenance within the EC (Incapampa and Camargo synclines) and SAZ (El Rosal and Entre Rios synclines). The >4 km uppermost Cretaceous-lower Miocene EC succession and ~2.5 km upper Oligocene-Miocene SAZ clastic successions record a shift from fluvial backbulge to pedogenic forebulge deposition. Braided, meandering, and lacustrine foredeep deposition records the most-rapid subsidence, with a later shift to progradational braided and alluvial fan deposition in the wedge-top zone. Growth strata preserved in EC and SAZ wedge-top deposits suggest unsteady eastward advance of the deformation front. Distal foreland deposits show west-directed paleocurrents with >1 Ga detrital zircon populations. Emerging Andean sources are indicated by east-directed paleocurrents, 36-25 Ma), Interandean Zone (IAZ, ~22-7 Ma) and SAZ (<6 Ma) can be linked to eastward passage of a flexural forebulge, recorded as a 50-200 m thick condensed zone in EC and SAZ basin fill. Integrated assessment of basin architecture, provenance, and exhumation highlights the potential influence of pre-Cenozoic IAZ heterogeneities on orogenic wedge growth.

  16. Relación de las direcciones de karstificación y del termalismo con la fracturación en las Cordilleras Béticas.

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    Benavente Herrero, J.

    1985-08-01

    Full Text Available Based on the interpretation of aerial photographs (scales between 1:10,000 and 1:35,000 an analysis is made of the various karstic fracture systems within the Betic Cordilleras of Southern Spain. The age of the fractured materials is comprised between the Middle Triassic to the Pliocene, with lithologies that. though predominantly carbonatic, also include celestite, and gypsum-bearing evaporites, Besides their directional frequency, the methodologies employed also allowed an estimate of the length relationships among fracture systems.
    The resulta so obtained, tested against field observations, indicate that two fracture systems (N 130-160 E and N 5-35 E are predominant, characterized respective1y by a relatively greater length of its componental fractures and by having a bimodal directional frequency, On a regional scale both systems correlate well with important structural lineaments that appear to have been active either as strike-slip or normal faults. Another fracture system striking roughly N 70-100 E presents comparatively less evidence of karstification, in spite of its considerable tectonic and paleogeographic significance (i. e., it parallels the boundary between internal ad external realms of the cordilleras, the socalled Cádiz-Alicante fracture system, The intersection of these systems (especially those striking N 70-100 E and N 130160 E appears to be a major control of the location of the main thermal springs , as well as of the intense seismic activity of the area.
    From a methodological standpoint. the results obtained in this study cover a scale level about which no information was previously available, and confirm existing hypotheses -based on satellite imaginery and microtectonic analysis-s- concerning the occurrence of changes in the orientation of the maximum vector of compressive stress. The strike of the karstification lineaments here signaled coincide with those obtained in analogous studies in the portuguese

  17. Generación de antecedentes científicos clave para un manejo forestal orientado a la conservación del Carpintero Negro (Campephilus magellanicus) en la cordillera de Nahuelbuta (Chile)

    OpenAIRE

    Espinosa Sepúlveda, Alejandro

    2017-01-01

    Es urgente estudiar los ecosistemas de bosque templado de la cordillera de Nahuelbuta, debido a que están siendo sometidos en la actualidad a fuertes procesos de fragmentación y empobrecimiento ecológico. Las consecuencias que generan dichos procesos son devastadoras, pues producen aislamiento y pérdida de conectividad entre las poblaciones de flora y fauna que habitan en fragmentos de bosque nativo, amenazando con ello la viabilidad y supervivencia de sus especies, sobre todo de aquellas que...

  18. Sedimentary cyclicity in early Pleistocene, evaporitic, playa-lake lacustrine deposits in the Guadix-Baza basin (Betic Cordillera, Spain); Ciclicidad sedimentaria en depositos lacustres evaporiticos tipo playa-lake del Pleistoceno inferior en la cuenca de Guadix-Baza (Cordillera Betica, Espana)

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Aguilar, J. M.; Guera-Menchan, A.; Serrano, F.; Palmqvist, P.

    2013-06-01

    The Guadix-Baza basin (Betic Cordillera, southern Spain) contains in its eastern sector an early Pleistocene (Gelasian and lowermost Calabrian) sedimentary unit that was deposited in a shallow lacustrine environment. Given that the chronological limits of this unit lie between 2.5 and 1.6 Ma BP, the thickness of its preserved sediments (400 m) and high sedimentation rate (44.4 cm/ka) are remarkable. Numerous sedimentary cycles marked by an alternation of marls and sands are commonly found in the marginal sectors and marls and gypsum in the central sector, which would owe their origins to permanent flooding and evaporation/ re-flooding phases due to global climatic changes. Spectral analyses carried out using Fourier transform have revealed the existence of temporary frequencies associated with sedimentary cycles of between 0.2 and 5.2 ka. The origin of these cycles may be associated with variations in solar radiation and oscillations in the Moons orbital position, which would induce global climatic changes resulting in the rise and fall of the water table of the lake. Autocorrelation analyses conducted separately on the marly and evaporitic levels support this conclusion, as they indicate the existence of significant direct correlations between about 4 to 12 sedimentary cycles, which would correspond to repetitions of the stratigraphic series over a time span of 1.3 to 4 ka. (Author)

  19. Flow in the shallow mantle in the westernmost Mediterranean: insights from xenoliths in Plio-Pleistocene alkali basalts from the eastern Betic Cordillera (SE Spain)

    Science.gov (United States)

    Konc, Zoltán; Hidas, Károly; Garrido, Carlos J.; Tommasi, Andréa; Vauchez, Alain; Padrón Navarta, José Alberto; Marchesi, Claudio; Acosta-Vigil, Antonio; Szabó, Csaba; Varas-Reus, Maria Isabel

    2016-04-01

    Peridotite mantle xenoliths in Plio-Pleistocene alkali basalts of the eastern Betic Cordillera (Cartagena area, Murcia, SE Spain) provide a snapshot of the structure and composition of the lithospheric mantle at the northern limb of the Alpine Betic-Rif arched belt in the westernmost Mediterranean. The xenoliths are spinel and plagioclase lherzolite with minor harzburgite and wehrlite, displaying porphyroclastic to equigranular textures. Regardless of composition and texture, the Crystal Preferred Orientation (CPO) of olivine shows an axial-[100] pattern characterized by a strong alignment of [100]-axes near or parallel to the peridotite lineation and a girdle distribution of [010]-axes with a maximum normal to the peridotite foliation. This CPO pattern is consistent with ductile deformation accommodated by dislocation creep with dominant activation of the high temperature {0kl}[100] olivine slip system, indicative of deformation by simple shear or combinations of simple shear and pure shear with a transtensional component. Calculated seismic properties are characterized by fast propagation of P-waves and polarization of fast S-waves parallel to olivine [100]-axis, indicating the flow direction. SKS and Pn anisotropy in the eastern Betics can be explained by a lithospheric mantle peridotite with similar fabric to the one displayed by the studied mantle xenoliths. Considering the limited thickness of the mantle lithosphere in the Betics (40-80 km), the measured azimuths and delays of SKS waves in the eastern Betics are consistent with a steeply dipping mantle foliation and a subhorizontal lineation with ENE strike. This geometry of the lithospheric fabrics implies active or frozen mantle flow with a dominantly strike-slip component subparallel to the paleo-Iberian margin. Synkinematic overprinting of mineral assemblages from the garnet-spinel to the plagioclase facies demonstrates 36-40 km uplift continuously accommodated by ductile shear thinning of the

  20. Cretaceous to Eocene evolution of the southeastern Canadian Cordillera: Continuity of Rocky Mountain thrust systems with zones of "in-sequence" mid-crustal flow

    Science.gov (United States)

    Simony, Philip S.; Carr, Sharon D.

    2011-09-01

    The ˜400 km wide, east-verging, retrowedge side of the southeastern Canadian Cordillera was predominantly formed in a tectonic setting of oblique plate convergence during the Cretaceous to Eocene. This paper documents the internal geometrical development of the retrowedge. In the External zone, the Rocky Mountains and Foothills are characterized by three major east-verging, Late Cretaceous to Eocene, thin-skinned, piggyback thrust and fold systems. They root westward into a basal décollement and accommodated ˜180 km of shortening. The Western Internal zone is characterized by tracts of metamorphic rocks and metamorphic core complexes (e.g. Kettle, Okanagan, Priest River and Valhalla), some of which are basement-cored domes (e.g. Frenchman Cap, Thor-Odin, and Spokane). They have a downward-younging progression of Late Cretaceous to Eocene metamorphism and deformation in infrastructural flow zones characterized by transposition foliation, migmatites, flow folds and 1-7 km thick shear zones. In the Eastern Internal zone, a relict ˜100-200 km wide Early Cretaceous orogen, that predated emplacement of ca. 100 Ma plutons, is nested between the External and Western Internal zones. The geology and architecture of the Internal and External zones can be explained by progressive development of major Late Cretaceous to Eocene shear zone systems in the Internal zone that can be directly linked with coeval thrust and fold systems in the External zone. The linkage was via Late Cretaceous activation and Late Cretaceous to Early Eocene reactivation of the 150-200 km-wide central portion of the Rocky Mountain basal décollement that lies beneath and translated the intervening Early Cretaceous orogen. During the latest stages of shortening, in the Early Eocene, extensional shear zone systems in the Internal zone, localized on tectonothermal culminations, were concomitant with shortening in the External zone. Motion of deep-seated Early Eocene décollements beneath some of these

  1. Holocene climatic variations in the Western Cordillera of Colombia: A multiproxy high-resolution record unravels the dual influence of ENSO and ITCZ

    Science.gov (United States)

    Muñoz, Paula; Gorin, Georges; Parra, Norberto; Velásquez, Cesar; Lemus, Diego; Monsalve-M., Carlos; Jojoa, Marcela

    2017-01-01

    The Páramo de Frontino (3460 m elevation) in Colombia is located approximately halfway between the Pacific and Atlantic oceans. It contains a 17 kyr long, stratigraphically continuous sedimentary sequence dated by 30 AMS 14C ages. Our study covers the last 11,500 cal yr and focuses on the biotic (pollen) and abiotic (microfluorescence-X or μXRF) components of this high mountain ecosystem. The pollen record provides a proxy for temperature and humidity with a resolution of 20-35 yr, and μXRF of Ti and Fe is a proxy for rainfall with a sub-annual (ca. 6-month) resolution. Temperature and humidity display rapid and significant changes over the Holocene. The rapid transition from a cold (mean annual temperature (MAT) 3.5 °C lower than today) and wet Younger Dryas to a warm and dry early Holocene is dated at 11,410 cal yr BP. During the Holocene, MAT varied from ca. 2.5 °C below to 3.5° above present-day temperature. Warm periods (11,410-10,700, 9700-6900, 4000-2400 cal yr BP) were separated by colder intervals. The last 2.4 kyr of the record is affected by human impact. The Holocene remained dry until 7500 cal yr BP. Then, precipitations increased to reach a maximum between 5000 and 4500 cal yr BP. A rapid decrease occurred until 3500 cal yr BP and the late Holocene was dry. Spectral analysis of μXRF data show rainfall cyclicity at millennial scale throughout the Holocene, and at centennial down to ENSO scale in more specific time intervals. The highest rainfall intervals correlate with the highest activity of ENSO. Variability in solar output is possibly the main cause for this millennial to decadal cyclicity. We interpret ENSO and ITCZ as the main climate change-driving mechanisms in Frontino. Comparison with high-resolution XRF data from the Caribbean Cariaco Basin (a proxy for rainfall in the coastal Venezuelian cordilleras) demonstrates that climate in Frontino was Pacific-driven (ENSO-dominated) during the YD and early Holocene, whereas it was Atlantic

  2. Spatio-temporal variability of snow water equivalent in the extra-tropical Andes cordillera from a distributed energy balance modeling and remotely sensed snow cover

    Science.gov (United States)

    Cornwell, E.; Molotch, N. P.; McPhee, J.

    2015-09-01

    Seasonal snow cover is the primary water resource precursor for human use and environmental sustain along the extratropical Andes Cordillera. Despite its importance, relatively little research has been devoted to understanding the properties, distribution and variability of this natural resource. This research provides high-resolution distributed estimates of end-of-winter and spring snow water equivalent over a 152 000 km2 domain that includes the mountainous reaches of central Chile and Argentina. Remotely sensed fractional snow covered area and other relevant forcings are combined with extrapolated data from meteorological stations and a simplified physically-based energy balance model in order to obtain melt-season peak SWE. Estimates show an overall coefficient of determination R2 of 0.61 compared to observations at 12 automatic snow water equivalent sensors distributed across the model domain, with R2 values between 0.32 and 0.88. Regional estimates of peak SWE accumulation show differential patterns strongly modulated by elevation, latitude and position relative to the continental divide. Average peak SWE increases by nearly 500 mm for every 1000 m in elevation gain for the central and southern sub-regions of the model domain, but this effect is much less pronounced in the northern reaches. The 3000-4000 m a.s.l. elevation band is the most significant accumulation area for most of the northern and central reaches of the domain, although the 4000-5000 m a.s.l. band, despite a smaller contributing area, almost doubles the accumulation amounts estimated for the lower adjacent subdomain. Snow accumulation reaches an earlier peak in the western Andes, and the eastern side of the continental divide shows lower snow accumulation at all elevations except for the southern region represented by the Neuquén River Basin. The results presented here have the potential of informing applications such as seasonal forecast model assessment and improvement, regional climate

  3. Palaeogeography and relative sea-level history forcing eco-sedimentary contexts in Late Jurassic epicontinental shelves (Prebetic Zone, Betic Cordillera): An ecostratigraphic approach

    Science.gov (United States)

    Olóriz, Federico; Reolid, Matías; Rodríguez-Tovar, Francisco J.

    2012-02-01

    The analysis of macroinvertebrate and foraminiferal assemblages from Upper Jurassic (Middle Oxfordian to Lower Kimmeridgian) epicontinental shelf deposits in the Prebetic (Betic Cordillera, southern Spain) reveals the influence of environmental changes. They are expressed as selected parameters in palaeogeographic and stratigraphic trends (litho- and microfacies, faunal composition, taphonomy), which are interpreted in the context of relative sea-level histories. Middle Oxfordian to early Kimmeridgian (Transversarium to Planula Chrones) rocks and faunal assemblages in comparatively distal sectors (distal shelf) show lower sedimentation rates (lumpy lithofacies), and higher proportions of ammonoids, planktic foraminifera, corrasion degree, microboring and encrustation. Landwards, towards the mid-shelf, eco-sedimentary conditions resulted in spongiolithic limestones and marl-limestone rhythmites with local development of microbial-sponge buildups. Greater distance from shore during relative sea-level highs accords with greater: (1) stratigraphic condensation; (2) abundance in ammonoids, planktic foraminifera and nubeculariids; and (3) degrees of corrasion, microboring and encrustation. These trends in faunal composition and taphonomy agree with backstepping phases, increasing ecospace and a longer exposition of shelly remains on the sea bottom. Decreasing distance from shore during relative sea-level lows relates to opposite trends, as evidenced by: (4) increasing terrigenous input and decreasing stratigraphic condensation; (5) impoverishment in ammonoids and planktic foraminifera; and (6) diminution of corrasion, microboring and encrustation. Phases of forestepping/progradation and aggradation, a reduction of ecospace for nekto-planktic organisms, and comparatively rapid burial of shell remains are interpreted to force the recorded trends. An ecostratigraphic approach is used here to correlate and characterise sea-level changes, applying high resolution stratigraphy

  4. Late Paleozoic to Early Jurassic tectonic development of the high Andean Principal Cordillera, El Indio Region, Chile (29 30°S)

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    Martin, Mark W.; Clavero R, Jorge; Mpodozis M, Constantino

    1999-01-01

    Regional mapping (1:50,000) and U-Pb and K-Ar geochronology in the El Indio region refines the knowledge of the distribution, lithostratigraphy, and age of the sedimentary, volcanic, and intrusive rocks that comprise the regionally extensive Pastos Blancos Group which is equivalent to the Choiyoi Group of the Argentine Frontal Cordillera. The Pastos Blancos Group (which we elevate to Group status herein) includes at least two diachronous volcanic-sedimentary sequences: an older felsic volcanic and volcaniclastic unit, the Guanaco Sonso sequence, that is Permian in age, and a younger bimodal volcanic and volcaniclastic unit, the Los Tilos sequence that is Middle Triassic to Early Jurassic. Sedimentary rocks of the Los Tilos sequence are transitional upward into the overlying Early to Middle Jurassic shallow marine limestones of the Lautaro Formation. Intrusions that make up the regionally extensive Permian to Early Jurassic plutons of the Chollay and Elqui-Limarı´ batholiths that were previously mapped as a single plutonic association, the Ingaguás Complex, include in the El Indio region at least three discrete intrusive units. These include: Early Permian (280-270 Ma) biotite granites, Early to Middle Triassic (242-238 Ma) silica-rich leucocratic granites and rhyolitic porphyries that made up the bulk of the Chollay Batholith, and a younger Late Triassic-Early Jurassic unit (221-200 Ma) of mainly intrusive rhyolitic porphyries, extrusive domes, and subordinate mafic intrusions and both felsic and mafic dikes, which are coeval with volcanic rocks of the Los Tilos sequence. Our data show that latest Paleozoic to Early Jurassic intrusive, volcanic, and sedimentary rocks in the El Indio region of the High Andes of Chile between 29-30°S likely formed during extension driven processes after the cessation of Carboniferous-Early Permian subduction along the western edge of Gondwana. These processes began by Late Permian time, but instead of recording a single and

  5. From Source to Sink: Exhumation of the North America Cordillera Revealed by Multi-dating of Detrital Minerals from Upper Jurassic-Upper Cretaceous Sevier Foreland Basin

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    Painter, C. S.; Carrapa, B.; DeCelles, P. G.; Gehrels, G. E.; Thomson, S. N.

    2013-12-01

    We sampled twenty-two Late Jurassic to Late Cretaceous syn-orogenic conglomerate clasts in proximal units in the Sevier fold-thrust belt and their distal sandstone equivalents up to 300 km east of the thrust front, in Utah, Colorado, Wyoming, and South Dakota. To better constrain depositional ages, these samples were analyzed using detrital zircon U-Pb (DZ U-Pb) geochronology. To identify a thermochronometer that measures source exhumation in the North America Cordillera, both zircon (U-Th)/He and apatite fission track (AFT) thermochronology was utilized, on both the conglomerate cobbles and sandstone (detrital) samples. Eleven samples were analyzed with zircon (U-Th)/He; however, discordant ages in the conglomerate cobble samples suggest that this system was not fully reset and never experienced T> ~180 °C in the source stratigraphy during the Sevier orogeny. Eleven other samples are analyzed using apatite fission track thermochronology (AFT); AFT ages are generally similar or older than depositional ages indicating that the detrital ages record source exhumation signals, and that exhumation depth corresponds to T>~120 °C. In order to test whether or not the youngest cooling AFT age population represents a source exhumation signal or a co-magmatic signal we here performed double dating of the detrital AFT samples using apatite U-Pb thermochronology. Maximum depositional ages using DZ U-Pb match existing age controls on basin stratigraphy. Our study shows that AFT is an effective thermochronometer to detect source exhumation for Cretaceous foreland stratigraphy in the western U.S.A. Lag-times (i.e. the difference between the source exhumation age and depositional age) are ~0 to 5 Myr with relatively steady-state to slightly increasing exhumation rates suggesting orogenic growth at this time. The very short lag times also indicate limited to no storage time between source and sink. The AFT lag time of the Early Cretaceous Kelvin Formation is ~5 Myr and represents

  6. Migración boyacense en la cordillera central, 1876-1945: Del altiplano cundiboyacense a los espacion de homogeneización antioqueña

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    2004-01-01

    Full Text Available L'article propose un point de vue historico-sociologique sur le processus migratoire « cundiboyacense » dans la cordillère central colombienne. Il rend compte de l'évolution historique et des phases de la migration, des processus socio-culturels, interprète les éléments déterminants du phénomène et explique le profil de son contact culturel avec l'élément d'ascendance antioquien dans la zone. L'espace andin choisi - les villes de Líbano et Murrillo dans le département de Tolima et la zone du désert de Letras et Manizales dans le département de Caldas - permet d'étudier le rôle historique de la migration inter-régionale du point de vue de son apport démographique, culturel et économique et de la confluence des différents éléments ethniques, et régionaux depuis la deuxième moitié du XIXème siècle. L'étude met en valeur l'importance des facteurs locaux - le manque de terre, la disposition au travail et les violences -, les facteurs externes - les offres de terre et de journaliers -, et les motivations personnelles - contacts personnels et modes de vie - comme autant d'éléments qui entrèrent en interaction durant les différentes phases migratoires et les circonstances historiques liées à la distribution de terres en friche et à l'expansion de la culture du café dans la cordillère centrale colombienne. El artículo ofrece un enfoque histórico-sociológico sobre el proceso migracional cundiboyacense en la cordillera central colombiana. Explica la evolución histórica y las fases de la migración, sus procesos socioculturales, interpreta las determinantes del fenómeno, y explica el perfil de su contacto y consecuente adaptación e integración con el elemento de ascendencia antioqueña en la zona de asentamiento. El espacio andino escogido -municipios del Líbano y Murillo en el departamento del Tolima y la zona del páramo de Letras y Manizales en el departamento de Caldas- permite estudiar el papel hist

  7. Evolución geoquímica y temporal del magmatismo básico mesozoico en las Zonas Externas de las Cordilleras Béticas

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    Aguirre, L.

    1995-08-01

    Full Text Available The Mesozoic basic magmatism found in the External Zones of the Betic Cordilleras (ZECB is represented either as «ophites» forming small dimension tectonic blocks intercalated in the Keuper gypsum-rich, clay sediments, or also as lava ilow bodies, most of them with pillow structures, within the Jurassic sedimentary rocks. Geochemical characteristics of these rocks indicate sorne differences between these two magmatic series. Two different chemical affinities have been carried out within the «ophites»: a with modal orthopyroxene and tholeiitic affinity; and b with modal olivine and transitionalalkaline affinity. Chemical characteristics of this last group are similar to those of the volcanic rocks from the Jurassic sediments. The field relationships found in sorne «ophite» outcrops al!ow us to deduce that the tholeiitic rocks are mostly present as extrusive rocks. However, their older whole-rock K-Ar ages range between 182 ± 9 and 187 ± 4 M.a., and do not correctly represent Upper Triassic ages. Transitional-alkaline «ophites» occur as subvolcanic rocks and their older obtained radiometric age is 137 ± 4 M.a. Al! these radiometric ages obtained may be intepreted as a result of the hybridization between the age of the Triassic magmatism and the very low- to low-grade metamorphism present in these rocks. This metamorphism is responsable for the new formed secondary paragenesis, made of prehnite + pumpel! yite + sericitie + mafic phyl!osicates. Radiometric age obtained in sorne intra-Jurassic volcanic rocks range between 155 ± 3 to 166 ± 4 M.a. These new radiometric data and field relationships are used to define the Mesozoic magmatic evolution in the ZECB. Tholeiitic magmatism was generated during an initial Triassic distensive stage. After this magmatic event, and as a consequence of an increment of the distensive regime, with important continental crust thickening, transitionalalkaline magmatism occurS. This

  8. Regeneración Natural del Roble Negro (Colombobalanus excelsa, Fagaceae en Dos Poblaciones de la Cordillera Oriental de los Andes, Colombia Natural Regeneration of Black Oak (Colombobalanus excelsa, Fagaceae in Two Populations from the Cordillera Oriental of the Colombian Andes

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    César Augusto Parra Aldana

    2011-12-01

    Full Text Available Colombobalanus excelsa es una especie endémica de la zona andina de Colombia, con cuatro poblaciones aisladas que forman rodales homogéneos denominados robledales negros. Se encuentra en categoría vulnerable de amenaza, debido principalmente a la conversión del bosque para usos agropecuarios; observaciones en campo indican que la regeneración natural bajo su propia cobertura es escasa. Se propone responder las siguientes preguntas: 1. ¿La estructura del bosque evidencia deficiencias en la regeneración natural de dos poblaciones de roble negro localizadas en la cordillera oriental de los Andes? 2. ¿El reclutamiento de fhmoreno@unal.edu.co está limitado por la disponibilidad y viabilidad de las semillas en las dos poblaciones estudiadas? Con este objetivo se establecieron 16 transectos permanentes de 0,1 ha para evaluar la estructura de adultos (DAP>10 cm y de la regeneración natural. Durante un año se realizó monitoreo sobre las épocas de fructificación, lluvia de semillas, germinación y banco de semillas. Los resultados muestran un suministro extremadamente bajo de renuevos y propágulos de roble negro, lo cual potencialmente puede poner en riesgo la persistencia de estos bosques. Esta situación obedece a diversos factores involucrados en el proceso de regeneración: desde baja producción de semillas de los árboles adultos, altos niveles de depredación pre-dispersión, alta proporción de semillas vacías, baja viabilidad de las semillas sanas, hasta alta mortalidad de las semillas sanas y viables que llegan al suelo. Si bien todos estos factores actúan en cascada, el último de ellos es quizás el que ejerce un efecto más dramático en el bajo éxito reproductivo de esta especie.Colombobalanus excelsa is an endemic species of the Andean region of Colombia, with four isolated populations, forming pure stands called black oak forests. It has been classified in the threat category ''Vulnerable'', mainly due to conversion of

  9. Influence of Unusual Climatic Conditions on the Rapid Rising of Water Level of the Palcacocha Lake and Its Connection with the Emergency Situation in the Cordillera Blanca, Perú.

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    Vilca, Oscar

    2017-04-01

    Influence of Unusual Climatic Conditions on the Rapid Rising of Water Level of the Palcacocha Lake and Its Connection with the Emergency Situation in the Cordillera Blanca, Perú. Oscar Vilca, Ricardo Durán, Cesar Portocarrero and Benjamín Morales National Institute for Research on Glaciers and Mountain Ecosystems - INAIGEM The climate alterations in 2016 have led to important issues within the Cordillera Blanca. These unusual climate events were evidenced by the rising temperature and the dropping relative humidity between December 2015 and January 2016 this was mainly influenced by the Niño phenomenon (ENSO), as well as subsequent events, like the one that occurred in november 2016, which had no presence of the ENSO, but was more severe, and has had direct influence on accelerated glacier fusion, this resulted the sudden growth of the water flow of the glacier basins of the Cordillera Blanca. Palcacocha was declared a dangerous lake due to its historical growth records. Currently, a partial monitoring to the water level of this lake is performed, and records are registered on a daily basis, with a methodology that includes analysis, quality control and the elaboration of a daily time line of the lake levels (december 2015 - december 2016). Subsequently, by using an area-volume curve, the levels are converted into volume, which can finally be inferred as water flows of net contribution to the lake. The accelerated increase of the level of the lake corresponds to the water flow contributed by glacier fusion, as that period (November 2016) did not record precipitation. The record observed has shown maximum thrust sheets of 22 mm (06/11/216) and 30mm (27/11/2016). This sudden increase of water flows in all the sub-basins with glaciers has caused concern and alarmed the population since the general perception in november pointed to a "drought", the most critical case being, the one that occurred in Jancapampa, where the river flows reached historic maximum levels

  10. Unidades tectónicas y estructura general de la Sierra de Gádor y zonas adyacentes (Cordillera Bética, provincia de Almería: implicaciones paleogeográficas

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    Delgado Salazar, F.

    2007-06-01

    Full Text Available In the Sierra de Gádor (Almeria province terrains belonging to the Internal Betic Zone crop out. According to stratigraphic, structural and petrologic features we have recognised five tectonic units. These units are called, from bottom to top, Gádor-Turón, Laujar, Murtas, Felix and Chirán unit. The lower fourth are ascribed to the Alpujárride Complex, whilst the last one is ascribed to the Maláguide Complex. We also discuss if the Felix unit may be included in the Intermediate Units. The Felix unit represents the Triassic palaeogeographic transition between the Alpujárride and the Maláguide, and it was located between both complexes during the alpine tectono-metamorphic evolution of the Betic Cordillera.En la Sierra de Gádor (provincia del Almería afloran rocas pertenecientes a la Zona Interna de la Cordillera Bética. En este sector hemos reconocido un total de cinco unidades tectónicas, en función de sus características estratigráficas, estructurales y petrológicas. Estas unidades se denominan, de abajo a arriba, unidad de Gádor-Turón, unidad de Laujar, unidad de Murtas, unidad de Felix y unidad de Chirán. Las cuatro más bajas las asignamos al Complejo Alpujárride, mientras que la más alta la asignamos al Complejo Maláguide. Se discute además la posible inclusión de la unidad de Felix dentro de las denominadas Unidades Intermedias. La unidad de Felix representa el tránsito paleogeográfico durante el Triásico entre el dominio Alpujárride y el Maláguide, y estaría situada entre ambos complejos durante la evolución tectono-metamórfica alpina de la Cordillera Bética.

  11. Relating geodynamic setting to periods of crustal growth and reworking as illustrated by the Phanerozoic granitoids of the Eastern Cordillera of South Peru

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    Reitsma, M.; Schaltegger, U.; Spikings, R.; Ulianov, A.; Gerdes, A.; Chiaradia, M.

    2012-04-01

    The granitoids that form the backbone of the Eastern Cordillera of Peru between 12 and 14°S, are the ideal material for a case study to relate geodynamic setting to crustal growth over the period of a Wilson cycle. Extension related plutons were emplaced in the back-arc region of the Western Gondwana margin during the Ordovician, Permo-Carboniferous, Triassic and Early Jurassic. With the onset of the Andean cycle in the Middle Jurassic the South American margin was under compression, the plutonic record of this period is in the study area restricted to the Eocene and Miocene. The Ordovician to Triassic back-arc related plutons share many geochemical characteristics that point to dominant crustal reworking as the main process during their formation. These are 1) their mainly felsic and peraluminous nature; 2) the similarity of whole rock REE and trace element compositions compared to those of average continental crust; 3) the presence of negative Nb-Ta anomalies only in the more evolved samples which indicates that these excursions have been obtained by crustal melting rather than from a slab fluid and 4) the presence of significant amounts of xenocrystic cores in zircon. According to the literature the last major episode of juvenile crust formation was during the Grenvillian age Sunsas event (1.2 - 0.9 Ga) related to the collision of Laurentia and south-western Amazonia during the assembly of Rodinia. Hf-isotopes on zircons from the Ordovician, Permo-Carboniferous and Triassic plutons confirm their origin as mainly crustal melts generated by reworking of Sunsas-age crust. Under these geodynamic conditions it is mainly the crust that melts due to an elevated geothermal gradient as the result of crustal thinning. However, data from Jurassic nepheline bearing syenite and Eocene hornblende diorite and monzonite have epsilon Hfi values well above those of Sunsas crust, indicating an important mantle component in the melts. The Jurassic geodynamic setting is interpreted

  12. Glacial and periglacial geomorphology and chronology around the Nevado de Chañi (Cordillera Oriental of Jujuy): implication for past climate in NW Argentina

    Science.gov (United States)

    Martini, M. A.; Strelin, J. A.; Kaplan, M. R.; Schaefer, J. M.

    2012-12-01

    steep active eroding valley walls. The minimum altitude and the local topographic context suggest that changes in the activity of rock glaciers correspond with local conditions (e.g., debris or talus supply) rather than climatic changes (e.g., temperature) around Chañi. Our geomorphological-based findings allow us to propose a preliminary correlation with other glaciated areas in the arid Andes and the northern Cordillera Oriental and with lake transgression phases recorded on the southern Bolivian Altiplano, during the late Pleistocene. The paleo-equilibrium line altitudes rise from east to west across the region indicating that the source of moisture came from the east and northeast during the past glaciations, which is similar to the present-day circulation scenarios along the north side of the Arid Diagonal.

  13. Automated recognition of quasi-planar ignimbrite sheets and paleo-surfaces via robust segmentation of DTM - examples from the Western Cordillera of the Central Andes

    Science.gov (United States)

    Székely, B.; Karátson, D.; Koma, Zs.; Dorninger, P.; Wörner, G.; Brandmeier, M.; Nothegger, C.

    2012-04-01

    The Western slope of the Central Andes between 22° and 17°S is characterized by large, quasi-planar landforms with tilted ignimbrite surfaces and overlying younger sedimentary deposits (e.g. Nazca, Oxaya, Huaylillas ignimbrites). These surfaces were only modified by tectonic uplift and tilting of the Western Cordillera preserving minor now fossilized drainage systems. Several deep, canyons started to form from about 5 Ma ago. Due to tectonic oversteepening in a arid region of very low erosion rates, gravitational collapses and landslides additionally modified the Andean slope and valley flanks. Large areas of fossil surfaces, however, remain. The age of these surfaces has been dated between 11 Ma and 25 Ma at elevations of 3500 m in the Precordillera and at c. 1000 m near the coast. Due to their excellent preservation, our aim is to identify, delineate, and reconstruct these original ignimbrite and sediment surfaces via a sophisticated evaluation of SRTM DEMs. The technique we use here is a robust morphological segmentation method that is insensitive to a certain amount of outliers, even if they are spatially correlated. This paves the way to identify common local planar features and combine these into larger areas of a particular surface segment. Erosional dissection and faulting, tilting and folding define subdomains, and thus the original quasi-planar surfaces are modified. Additional processes may create younger surfaces, such as sedimentary floodplains and salt pans. The procedure is tuned to provide a distinction of these features. The technique is based on the evaluation of local normal vectors (perpendicular to the actual surface) that are obtained by determination of locally fitting planes. Then, this initial set of normal vectors are gradually classified into groups with similar properties providing candidate point clouds that are quasi co-planar. The quasi co-planar sets of points are analysed further against other criteria, such as number of minimum

  14. Evaluation of metasomatic changes in an interlayered blueschist-greenschist sequence (Coastal Cordillera, Chile) by combining geochemical data with equilibrium assemblage diagrams

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    Halama, Ralf; Konrad-Schmolke, Matthias

    2014-05-01

    In the Coastal Cordillera of Central Chile, a spectacular sequence of interlayered blueschists and greenschists occurs in coastal outcrops near Pichilemu. Three explanations are generally proposed to interpret the interlayering of metamorphic rocks that represent distinct metamorphic facies: 1. Differences in the pressure-temperature (P-T) conditions of equilibration and late-stage tectonic juxtaposition, 2. Chemical differences between the layers inherited from the protolith, and 3. Differences in the degree of metasomatic overprint during metamorphism. Investigations of such interlayered sequences can shed light on the mobility of elements and fluid-rock interaction during metamorphism. To identify the processes responsible for interlayering, geochemical analyses were combined with petrologic investigations involving the calculation of isothermal and isobaric binary phase diagrams using the THERIAK-DOMINO [1] software. Major mineral phases in blueschist and greenschist layers are amphibole, white mica, chlorite, and albite with subordinate amounts of titanite, epidote, hematite and apatite. The mineralogy of blueschist and greenschist layers is similar, albeit the modal proportions differ, causing the distinct colouring. Peak P-T conditions of blueschists reach 370±20 °C at 10±1 kbar [2]. The layering on a cm-to-dm scale and the similar mineralogy suggest that both blueschist and greenschist layers experienced a similar P-T evolution. For adjacent blueschist-greenschist pairs, blueschists have consistently higher Si and Na contents, whereas greenschists are relatively enriched in Al, Mg and total Fe. However, the observed major element geochemical trends are inconsistent with magmatic differentiation. For several blueschist-greenschist pairs, ratios of incompatible trace elements, which are indicative of the protolith composition and considered as relatively immobile during low-T metamorphism (Th/Yb, Nb/Yb), are near identical. These features point to

  15. Estudio sedimentológico del Keuper inferior, a partir del análisis de facies, en el sector central de la Cordillera Bética. Algunas consideraciones paleogeográficas

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    López Chicano, M.

    1989-12-01

    Full Text Available The lower Keuper of the central sector of Betic Cordillera shows a predominance of clays with variegated colours. They have intercalations of thin layers of sandstones (fine grain, gypsum and carbonates. Through sedimentological and stratigraphic analysis we can conclude that these materials are from a systems tract fluviocoastal further more it allows us to distinguish sorne different facies types which characterize the following subenvironments. They are set in a framework of mud flat, found on a vast tidal coastal lutitic plain. Terrigenous sediments (fine sands from the mainland are deposited on the lutitic plain by ephemeral streams. In this coastal environment there are subenvironments of salt marsh, salt pans, sabkha, coastal lagoons, etc. The distribution in time and space of these facies was mainly controlled by the climate and the frequent incursions of the sea over the coastal plain, facilited by the flat geographical nature of coastline.En el Keuper inferior del sector central de la Cordillera Bética hay un predominio de materiales arcillosos, de colores abigarrados, con niveles intercalados de areniscas de grano fino, yesos y carbonatos. A partir del análisis estratigráfico y sedimentológico se han interpretado estos materiales como pertenecientes a un cortejo fluviocostero. Este análisis ha permitido, previamente, diferenciar diversas asociaciones de facies que caracterizan varios ambientes sedimentarios. Esencialmente, se enmarcan en un mud flat, dentro de una extensa llanura costera parcialmente afectada por mareas. A ésta llegan sedimentos detríticos continentales (arenas finas mediante corrientes fluviales efímeras. Dentro de este mismo medio costero aparecen ambientes de marisma, salt pans, sabkha, laguna, etc. La evolución en el tiempo y en el espacio de estas facies está controlada principalmente por el clima y por las frecuentes ingresiones del mar sobre la llanura costera, las cuales están facilitadas por la

  16. El Cenozoico del alto río Teno, Cordillera Principal, Chile central: estratigrafía, plutonismo y su relación con estructuras profundas The Cenozoic of the upper Teno River, Cordillera Principal, Central Chile: stratigraphy, plutonism and their relation with deep structures

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    José Piquer

    2010-01-01

    Full Text Available La evolución geológica cenozoica del sector central de la Cordillera Principal a ~35°S, se encuentra íntimamente relacionada con la evolución de estructuras profundas, las cuales habrían controlado, en distintas etapas de su historia, tanto la depositación de secuencias volcano-sedimentarias como el ascenso y emplazamiento de cuerpos intrusivos. Estudios estratigráficos en el entorno de estas estructuras, permiten confirmar la edad cenozoica de un conjunto de rocas piroclásticas y sedimentarias que subyacen concordantemente a lavas andesíticas de la Formación Abanico (asignada al Eoceno Tardío-Mioceno Temprano a Medio. Se determinó la existencia de cuatro fases intrusivas principales (diorita, granodiorita, pórfido riodacítico y pórfido dacítico, en ese orden de intrusión, cuyos productos afloran siguiendo una franja de orientación norte-sur. La granodiorita fue datada en 7,8±0,4 Ma (K-Ar en biotita. Pórfidos riodacíticos, considerados como facies marginales de la unidad anterior, se dataron en 7,9±0,4 Ma (K-Ar en fenocristales de plagioclasa. Se reconocieron dos estructuras de importancia regional: el Corrimiento El Fierro, y, más al oeste, se definió el Sistema de Fallas Infiernillo-Los Cipreses. En la caracterización de esta última estructura, se utilizó la modelación magnética de secciones como complemento a la información geológica. Se interpreta que el ascenso de las distintas fases intrusivas mencionadas fue controlado por el Sistema de Fallas Infiernillo-Los Cipreses. Este, al igual que el Corrimiento El Fierro, habría actuado como una falla normal de borde de cuenca durante el Eoceno Tardío-Moceno Medio, controlando la depositación de productos volcánicos y sedimentarios de la Formación Abanico. Ambas fallas fueron reactivadas en modo inverso durante un importante episodio de contracción tectónica y de elevada presión de fluidos inducida por circulación de magmas, en el Mioceno Tard

  17. El neopaleozoico de la Sierra de Castaño (Cordillera Frontal andina, San Juan, Argentina: Reconstrucción tectónica y paleoambiental The neopaleozoic of the Sierra de Castaño (Andean Cordillera Frontal, San Juan, Argentina: Tectonic and paleoenviromental reconstruction

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    Pedro Busquets

    2013-01-01

    Full Text Available Se efectúa el análisis estratigráfico de la secuencia neopaleozoica aflorante en la Sierra de Castaño (Cordillera Frontal de la provincia de San Juan, donde han sido reconocidas tres unidades estratigráficas. La basal corresponde a la Formación Cerro Agua Negra (Carbonífero tardío-Pérmico temprano?, formada por areniscas y pelitas depositadas en ambiente marino de plataforma somera y litoral. Sobre ella se dispone la Formación San Ignacio, compuesta por sedimentitas silicoclásticas (desde conglomerados hasta pelitas, calizas estromatolíticas-microbiales, rocas volcánicas, en su mayoría de composición mesosilícica y ácida, y depósitos volcanoclásticos. Estas últimas rocas, probablemente depositadas hacia fines del Carbonífero tardío o en el Pérmico más temprano, cubren en discordancia angular a las de la Formación Cerro Agua Negra en la Sierra de Castaño. Dentro de la Formación San Ignacio fueron identificadas 3 asociaciones de facies sedimentarias. La inferior (AFa está formada por brechas, conglomerados brechosos y areniscas líticas, sedimentadas en sistemas aluviales y fluviales entrelazados que rellenaron una irregular topografía labrada sobre la Formación Cerro Agua Negra. La asociación de facies media (AFb, compuesta por conglomerados, areniscas y pelitas, desarrolla ciclos granodecrecientes de escala métrica muy probablemente originados en sistemas fluviales de alta sinuosidad. La asociación de facies superior (AFc comprende calizas estromatolíticas microbiales, pelitas, niveles de volcanitas y piroclastitas, originadas en cuerpos de aguas someros sujetos a recurrente actividad volcánica. La Formación San Ignacio permite caracterizar el pasaje entre las sucesiones no volcánicas de la Formación Cerro Agua Negra y el intenso magmatismo representado en el Grupo Choiyoi (Pérmico medio-Triásico Inferior. Además demuestra la existencia de dos eventos mayores de deformación tectónica en la regi

  18. ESTRUCTURA, DIVERSIDAD Y DINÁMICA DE LA VEGETACIÓN EN EL ECOTONO BOSQUE-PÁRAMO: REVISIÓN DE LA EVIDENCIA EN LA CORDILLERA DE MÉRIDA

    Directory of Open Access Journals (Sweden)

    Luis Daniel LLAMBÍ

    2015-07-01

    Full Text Available En los Andes tropicales, el límite altitudinal de los bosques corresponde a una compleja zona de transición entre el bosque paramero y el páramo andino. En el límite inferior de esta zona ocurre a su vez una transición gradual entre el bosque y las selvas nubladas. La ordenación del territorio en estos ecosistemas se ha convertido en un tema prioritario en virtud de la creciente amenaza que representan para su conservación las actividades agropecuarias y la minería. En este trabajo se revisaron las investigaciones realizadas en la Cordillera de Mérida (Venezuela sobre los cambios en la estructura, diversidad y respuesta a disturbios de la vegetación a lo largo del ecotono bosque-páramo. Los resultados de estas investigaciones documentan la alta riqueza de especies y formas de vida que caracterizan la vegetación del ecotono, así como una alta tasa de recambio de especies a lo largo del gradiente de elevación. Así mismo, estudios sobre la dinámica sucesional de la vegetación en áreas intervenidas por la agricultura en diferentes posiciones a lo largo de la transición, indican que las leñosas del bosque muestran una capacidad mucho menor de colonización de las áreas perturbadas que las especies dominantes del páramo. Con base en la evidencia disponible, se discuten elementos estructurales que pueden servir de base para la delimitación de los ecosistemas presentes en la zona de transición y se enfatiza la necesidad de diseñar estrategias de conservación y restauración asistida que partan de interpretar el ecotono bosque-páramo como una unidad dinámica integrada.Vegetation Structure, Diversity and Dynamics in the Forest-Paramo Ecotone: A Review of the Evidence in the Cordillera de MéridaIn the tropical Andes, the mountain treeline corresponds to a complex transition zone between páramo forests and páramos. In the lower limit of this ecotone there is a more or less gradual transition between mountain cloud forests and

  19. Efecto del Compost de Biosólidos en la producción de plantines de Austrocedrus Chilensis (ciprés de la cordillera Effect of Biosolids Compost on seedling production of Austrocedrus Chilensis (ciprés de la cordillera

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    Gustavo Basil

    2009-06-01

    Full Text Available La utilización de compost de residuos urbanos como sustrato en contenedores es una alternativa interesante a nivel económico y ambiental, dado que reduciría el uso de turba y «tierra negra» en la producción de plantines, y la disposición de residuos en vertederos. En el presente trabajo se estudió el efecto de 0, 30 y 50% de compost de biosólidos en el crecimiento inicial (primer año de ciprés de la cordillera, y el efecto durante los dos años siguientes de un tratamiento único con 50% de compost en el crecimiento posterior y el estado nutricional de los plantines. Se determinó diámetro y altura a 18, 25 y 37 meses, biomasa aérea y radicular a 25 y 37 meses, y concentración foliar de C, N, P, K, Ca y Mg a 37 meses. A pesar de que los tres tratamientos iniciales fueron homogeneizados al año en un único tratamiento con 50% de compost, se encontraron diferencias significativas de diámetro, altura y biomasa aérea y radicular entre los tratamientos originales en todas las fechas analizadas, correspondiendo los mayores valores a los tratamientos con compost. Al finalizar el ensayo, las concentraciones foliares de nutrientes fueron muy similares en todos los plantines, excepto Mg que fue mayor en el tratamiento original con 50% de compost. Los resultados muestran la importancia de los primeros meses de crecimiento en el desarrollo posterior de los plantines de ciprés y el valor potencial de los compost de biosólidos como sustrato para la producción de esta especie en contenedores.Using composts of urban waste, including biosolids, as substrates for containerized plant production is a sound economic and environmental alternative, since it could reduce the use of peat- and «black earth»-based media, and the disposal of organic wastes in landfills. The objectives of this work were to study the effect of 0, 30 and 50% biosolids compost on the initial growth (first year of cypress (Austrocedrus chilensis D. Don, and the effect

  20. El Transporte Terrestre a través de la Cordillera Cantábrica en Tiempos de Felipe II. Un Estudio a partir de la Correspondencia de Simón Ruiz con Laredo

    Directory of Open Access Journals (Sweden)

    Oscar LUCAS VILLANUEVA

    2012-12-01

    Full Text Available El presente trabajo analiza las condiciones y costes del transporte terrestre en tiempos de Felipe II en el ámbito de las relaciones comerciales entre Castilla y el espacio atlántico septentrional, a partir de la información proporcionada por las cartas comerciales del mercader Simón Ruiz. Los datos nos indican que las dificultades geográficas no fueron tan determinantes para el tráfico a través de la Cordillera Cantábrica como se había pensado hasta ahora. El artículo también aborda la cuestión de los costes que comportaban las operaciones de traslado de mercancías desde los puertos a los mercados del interior peninsular. Las fuentes nos permiten un detallado análisis de los mismos así como un cálculo de su cuantía en proporción a la suma total de la operación, relativizando la importancia de los mismos, lo que favorecería los traslados de mercancías por vía terrestre para distancias relativamente grandes.

  1. Petroglifos en rocas de la Cordillera de la Costa así como en los raudales de los ríos de la selva virgen venezolana. La interpretación por Alejandro de Humboldt y observaciones actuales

    Directory of Open Access Journals (Sweden)

    Ursula Thiemer-Sachse

    2003-04-01

    Full Text Available Article in Spanish, Abstracts in English, German and Spanish.Indian Petroglyphs on rocks of the Venezuelan Cordilleras mountain chain as well as Región de los Raudales, the tropical forest headwaters. A. v. Humboldt’s petroglyph interpretations and present observations. Throughout the world the interpretation of petroglyphs and other prehistoric rock art is a difficult endeavor. Some of the factors contributing to these puzzles include, among others: a lack of knowledge about the circumstances (such as rituals and the concomitant ideas that played key roles in the creation of the petroglyphs. Even the famous nineteenth-century German explorer Alexander von Humboldt, who first saw South American petrogpyphs while mapping the river system connecting the Amazon and Orinoco rivers in Venezuela, ventured to decipher and analyze the complicated artwork as part of his interest in ancient civilizations. Since the time of Humboldt numerous other researchers have attempted to decode and provide a culturally-situated analysis of petroglyph’s meanings.

  2. La formación radiolarítica Jarropa: definición y significado en el Jurásico Subbético (Cordillera Bética

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    Vera, J. A.

    1997-08-01

    Full Text Available The Jarropa Radiolarite Formation is defined formally, for the first time, according to the international guide of stratigraphic nomenclature, and the holostratotype and two parastratotypes are described. This is a very characteristic Jurassic unit of the Subbetic (Betic Cordillera in which point out the presence of radiolarite levels, together with siliceous marlstones, marls and clays. Two members are differentiated: a lower member of green, radiolarites and siliceous marls, and an upper member of red, siliceous clays and marls, both being recognizable in most of the outcrops. The age of this formation in the holostratotype, known mainly from the study of their radiolarians, is Late Callovian-Oxfordian. In other stratigraphic sections (including some parastratotype is verified that the exact age of the bottom of the formation, and of the boundary between the two before described members are heterochronous, within the Uppermost Bajocian-Lowermost Kimmeridgian. They are pelagic sediments, deposited during the expansive phase of the Southern Iberian Continental Paleomargin, in areas far from the continent with thin continental crust. They have a great analogy with deposits outcropping in others Mediterranean Alpine domains (Apennines, Alps, Dinarids, etc. also accumulated during Jurassic extensive phases of continental margins adjacent to the Tethys. The depositional bathymetry is estimated in a few hundreds of meters, without a necessary relation with the calcite compensation depth (CCD.Se define formalmente, por primera vez, la «Formación Radiolarítica Jarropa» de acuerdo con las normas internacionales de nomenclatura estratigráfica, y se describen el holoestratotipo y dos paraestratotipos. Se trata de una unidad litoestratigráfica muy característica del Jurásico del Subbético (Cordillera Bética en la que destacan la presencia de niveles de radiolaritas, junto con margas y arcillas silíceas. Se diferencian dos miembros, uno

  3. Un modelo de la historia de la vegetación de la Cordillera de La Costa de Chile central-sur: la hipótesis glacial de Darwin A model for the history of vegetation of the Coastal Range of central-southern Chile: Darwin's glacial hypothesis

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    CAROLINA VILLAGRÁN

    2001-12-01

    Full Text Available En Chile central-sur, entre los paralelos 37 y 43º S, existen comunidades aisladas de coníferas y tundras magallánicas, cuya distribución principal es altoandina y/o de latitudes altas. De acuerdo a Darwin (1859, en general, estas "islas" corresponderían a los remanentes de poblaciones glaciales, que ocuparon sitios de menor altitud y latitudes más bajas, durante el avance de los hielos. Se desprende de esta hipótesis que, a lo largo de Chile, se habrían producido desplazamientos de la flora austral y andina hacia el Valle Longitudinal, durante la última glaciación, y en sentido inverso, durante el Tardiglacial (14.600-10.000 14C años AP y Holoceno (después de 10.000 14C años AP. Considerando esta hipótesis, en este trabajo se analizan dos secuencias palinológicas, procedentes de las cimas de la Cordillera de la Costa de la Región de los Lagos (cordilleras de Nahuelbuta y de Sarao, y se correlacionan con registros publicados, tanto de otros sitios de cimas de cerros, como de sitios de baja altitud, todos ellos procedentes de las regiones de Los Lagos y de Los Canales. Los registros de las cimas de la Cordillera de La Costa, analizados en este estudio, muestran la siguiente secuencia cronológica: (1 El registro de la Cordillera de Sarao documenta, para el Holoceno temprano, a partir de 9.040 14C años AP, la colonización del elemento de tundras magallánicas y bosque norpatagónico con coníferas, aunque ambas formaciones alcanzan su máximo desarrollo en el Holoceno medio, sucedidas por el elemento de bosque norpatagónico-valdiviano, en el Holoceno tardío. (2 El registro de la Cordillera de Nahuelbuta muestra que la colonización de estos mismos elementos se produce, recién, en el Holoceno medio, alrededor de 5.430 14C años AP. Otros registros de polen de las cimas de la Cordillera de La Costa (Cordillera Pelada y de Piuchué muestran que el desarrollo de ambas formaciones se produjo en el Tardiglacial y Holoceno temprano

  4. Las doleritas toleíticas triásicas del sector SE de la Cordillera Ibérica: petrología y geoquímica

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    Bastida Cuairán, J.

    1999-12-01

    Full Text Available The tholeiitic dolerites that crop out in three diapirs of the SE of the Iberian Chain (Alfarp, Quesa and Lugar Nuevo de Fenollet, Valencia, are the expression of evolved (low Ni, Cr and mg* values basic magmas, injected into poorly lithified sediments (lutites, marls and gypsum which represent the Upper Triassic (Keuper facies-Hettangian boundary, developing sills with reduced thickness. Their mineral and whole-rock geochemical compositions indicate a continental tholeiitic affinity and certain similarities to a MORB composition and, on the other hand, show that the Alfarp dolerites represent the less evolved compositions, whereas the Fenollet dolerites show a significantly greater differentiation. These rocks are the expression of a shallow magmatism, related to the initial stages of the mesozoic rifting that affected the intersection of the Celtiberian Rift with the Betic Graben. This magmatism is clearly different of the isochronous tholeiitic magmatism (dolerites which crops out at the Pyrenees and Betic.Las doleritas toleíticas aflorantes en diapiros triásicos del SE de la Cordillera Ibérica (Alfarp, Quesa y Lugar Nuevo de Fenollet, SE de Valencia representan líquidos diferenciados (valores bajos en Ni, Cr y mg* emplazados como sills, de escaso espesor, por debajo de sedimentos (arcillas, margas y yesos, poco consolidados, del límite Triásico superior-Hettangiense. Su composición mineral y geoquímica, con afinidad toleítica continental y similitud a MORB, evidencia el carácter menos diferenciado de las doleritas de Alfarp, respecto a las de Quesa, siendo las doleritas aflorantes en Fenollet las que presentan una composición más evolucionada. Estas doleritas son la expresión de un magmatismo poco profundo, asociado al inicio del rifting mesozoico, desarrollado en la zona de intersección del rift celtibérico y el borde NE del surco bético. Este magmatismo presenta claras diferencias respecto a las doleritas toleíticas, menos

  5. Evaluación del conocimiento florístico de la cordillera Cantábrica (España a partir de bases de datos de biodiversidad

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    Jiménez-Alfaro, B.

    2009-12-01

    un requisito fundamental para la conservación de cualquier región, y las bases de datos biológicas representan una herramienta básica para la estimación de medidas de diversidad. Sin embargo, muchas regiones biogeográficas fragmentadas administrativamente suelen estar caracterizadas por bases de datos heterogéneas realizadas desde diferentes instituciones y a diferentes escalas. En este trabajo se evalúa el conocimiento florístico de plantas vasculares aportado por bases de datos regionales en la Cordillera Cantábrica (España. Se utilizaron los datos georeferenciados de bases de datos no superpuestas, provenientes de una colección de herbario y de un atlas completado con información bibliográfica, los cuales fueron comparados en función de los patrones temporales y espaciales (cuadrículas UTM de 10x10 km de riqueza florística, utilizando estimadores no paramétricos (ICE, Chao2, Jack1 y Jack2 para medir el grado de conocimiento que las bases de datos reflejan. Ambas fuentes fueron también comparadas con una base de datos nacional con información sobre todo el área de estudio. Las bases de datos regionales detectaron unos patrones similares de prospección histórica y espacial, y los valores de riqueza florística observada estuvieron altamente correlacionados con la base de datos nacional, si bien se detectó una elevada heterogeneidad en la riqueza conocida por UTM. Las estimaciones de riqueza florística indicaron que ambas bases de datos están incompletas, aunque permitieron realizar una estimación de la riqueza total de la Cordillera Cantábrica (en torno a 3590 especies y subespecies. Los resultados obtenidos sugieren que bases de datos incompletas, parciales y de diferente naturaleza pueden aportar información similar para la detección de áreas poco prospectadas, aunque la incorporación de referencias bibliográficas a las bases de datos de herbarios puede ofrecer mejores estimaciones de riqueza florística. Sin embargo, una valoraci

  6. Ecología y conservación de Centaurium somedanum M. Laínz (Gentianaceae, planta endémica de la Cordillera Cantábrica (España

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    Jiménez-Alfaro, B.

    2005-12-01

    nature spécifique de son habitat et le manque de celui-ci semblent le principales causes de la rareté et la fragilité de l'espèce. Avec C. somedanum, d'autres espèces et communautés végétales rares des Monts Cantabres nous signalent la nécessité de conserver les milieux liés à ce type de sources, maintenant soumises à différentes menaces. [es] Centaurium somedanum es un endemismo cantábrico conocido en menos de veinte localidades del extremo occidental de la Cordillera Cantábrica. Con el fin de conocer su estado actual de conservación, se han realizado un Estudio Básico y un Estudio Integrado del Habitat, definiendo los requerimientos del habitat de la planta, el número de poblaciones y su estado demográfico. Los resultados del estudio han permitido constatar la desaparición de la especie en algunas de las localidades en que había sido citada. C. somedanum es un caméfito de vida corta, del que actualmente se conocen catorce poblaciones, y de ellas sólo cuatro superan los quinientos individuos. Ocupa hábitats muy específicos, en torno a surgencias de aguas carbonatadas, desde 500 a 1600 m de atitud. La especificidad y escasez de su habitat son las principales causas de su rareza y amenaza. Junto a C. somedanum, otras especies y comunidades vegetales raras de la Cordillera Cantábrica señalan la necesidad de conservar los ambientes ligados a este tipo de surgencias, actualmente sometidas a diferentes amenazas.

  7. Tectonic comparisons of Caucasus and California cordillera

    Energy Technology Data Exchange (ETDEWEB)

    Mulhern, M.E.

    1986-05-01

    Many parallels exist between the Caucasus region, shaped as the Eurasian and Arabian-African plates converged during the Cenozoic Alpine orogeny, and California, where the North American and Pacific plates interact. The Forecaucasian platform hosts many large oil and gas fields in molasse-filled foredeeps of high heat flow. Production is from Permian to Pliocene tight anticlines on reverse faults, diapiric structures, shoe-string sands of the prolific Maikop series, and Tertiary fanglomerates and sand lenses. Although not an exact parallel, this production suggests potential in Paleozoic and Mesozoic marine and Tertiary fanglomeratic, tuffaceous, and fluvial sediments in basins of the sparsely drilled Basin and Range. The Greater Caucasus, like the Sierra Nevada, show Paleozoic-Mesozoic geosynclinal sedimentation, subduction, and granitic magmatism. The former have undergone much folding, thrusting, and Quaternary volcanism. Jurassic bituminous limestone is exposed, a source for the petroliferous Transcaucasian Intermontane depression. The latter is filled with thick Mesozoic-Cenozoic flysch and molasse and, like California's Great Valley forearc basin, orogenic terrane and permeable soils favor enology. Sources also include Eocene and Miocene diatomaceous and bituminous clays. Reservoirs include prolific Pliocene sands, Eocene olistostromes, fractured tuffaceous rocks, and Cretaceous-Miocene sandstones in anticlines and stratigraphic traps. Migration to basin flanks was aided by compression. The Lesser Caucasus, a continuation of the main ophiolite foldbelt of Turkey, shares a subduction and accretionary history with the Franciscan melange. This microplate was obducted to Eurasia as the prong-shaped Arabian plate moved it and other microplates of the east Mediterranean in several directions (the Turkish microplate dextrally along the North Anatolian transform fault) and deformed wide areas.

  8. Cuando el invierno llega a la cordillera

    OpenAIRE

    Rubio, Julia

    2013-01-01

    Mostrar y/o mejorar los lineamientos, en materia de Seguridad e Higiene en el Trabajo, que utiliza Fluor Techint para el control en la construcción minera. Identificar, evaluar y controlar los riesgos presentes en cada ambiente de trabajo. Poder estimar los valores límites, destinados a proteger a los trabajadores tanto del estrés por frío como de las lesiones causadas por el mismo. Confeccionar un programa integral de prevención de riesgos laborales.

  9. Bolivia Altiplano and Cordillera Occidental Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The gravity station data (59,933 records) were compiled by various organizations. This data base was received in June, 1993. Principal gravity parameters include...

  10. Análisis espectral de materiales geológicos en la Cordillera Volcánica Central de Costa Rica y su relación con la detección remota de anomalías

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    Rejas, J. G.

    2014-12-01

    Full Text Available The aim of this work is the comparative study of methods for calculating spectral anomalies from imaging spectrometry in several test areas of the Central Volcanic Range (CVR of Costa Rica. In the detection of anomalous responses it is assumed no prior knowledge of the targets, so that the pixels are automatically separated according to their spectral information significantly differentiated with respect to a background to be estimated, either globally for the full scene, either locally by image segmentation techniques. We used spectral ranges of visible-near infrared (VNIR, shortwave infrared (SWIR and thermal (TIR data cubes hiperepectrales from HyMAP airborne sensors and MASTER. We have designed experiments on natural scenes of the CVC, and semi-urban of different complexity, analyzing the behavior of the standard RX (Reed & Xiaoli, 1990 anomaly detector and different approaches based on imaging and dimensionality reduction. In this paper we propose a new technique for anomaly detection in hyperspectral data called DAFT (Detector de Anomalías de Fondo Térmico, as a Projection Pursuit (Malpica et al., 2008 variant, based on dimensionality reduction by projecting anomalies or targets with unknown spectral signature to the background, in a range thermal spectrum wavelengths. We discuss the results considering their implications on geological processes, as well as their use as terrestrial analogs for planetary exploration.El objetivo del presente trabajo es el estudio de bandas de absorción y reflexión de espectros de materiales geológicos presentes en distintas áreas de test de la Cordillera Volcánica Central (CVC de Costa Rica, y su correlación con el cálculo automático de anomalías a partir de espectrometría de imagen de alta resolución, también llamada teledetección hiperespectral. En la detección de respuestas anómalas se asume un no conocimiento previo de los objetivos. Los píxeles se separan automáticamente en funci

  11. Glacier changes since Local Last Glacial Maximum in the South-West slope of Nevado Hualcán, Cordillera Blanca, Peru, deduced from moraine mapping and GIS-based analysis

    Science.gov (United States)

    Giráldez, Claudia; Palacios, David; Haeberli, Wilfried; Úbeda, Jose; Schauwecker, Simone; Torres, Judith

    2014-05-01

    Anticipating and assessing hazards and risks associated with the shrinking of surface and subsurface ice in cold mountain chains is facilitated by empirical-quantitative data on present and past rates of change, as well as by a general understanding of related landforms and landscape evolution through time. Rock/ice avalanches and devastating outburst floods from glacial lakes indeed constitute a major cause of severe damage in populated mountain areas such as the Cordillera Blanca whose combination of tectonic, topographic and glaciological characteristics make it a threatened region. This study focuses on the Río Chucchún catchment above the city of Carhuaz, which was recently affected by a flood/debris flow from a rock/ice avalanche impacting a recently grown lake (Laguna 513). Traces left by past glaciations strongly affect the current geomorphodinamic behaviour of the catchment. For instance, a prominent sediment-filled glacial overdeepening behind Younger Dryas (YD) moraines (Pampa de Shonquil) with its retention function strongly influenced the chain of processes initiated by the outburst of Laguna 513. The aim of this study is to reconstruct earlier glacial phases in the SW slope of Nevado Hualcán (Río Chucchún catchment), in order to compile quantitative information on surface areas and Equilibrium Line Altitudes (ELAs). To do so, glacier stages were assigned to five different glacial phases, through photointerpretation and moraine cartography: 2003; 1962; Hualcán-I-LIA (15th to 18th centuries); Hualcán-II-YD (~12,5 ka BP); and Hualcán-III-LLGM (~34 to 21 ka BP). Glacial stages Hualcán-I-LIA, Hualcán-II-YD and Hualcán-III-LLGM present relative dating based on previous studies from different authors in the Peruvian Andes. Once glaciers were delimited, their surface areas and Equilibrium Line Altitudes (ELAs) were calculated. For ELA estimation three different methods were used: the mid-range elevation, the Accumulation Area Ratio (AAR), and the

  12. APROPIACIÓN INCA EN LA CORDILLERA DE CHILLA, SUROESTE DE LOS ANDES DEL ECUADOR: EL CASO DEL SITIO GUIÑAYZHU (Inca Appropriation in the Chilla Mountain Range, Southwest of the Andes of Ecuador: the Case of the Guiñayzhu Site

    Directory of Open Access Journals (Sweden)

    Mary Jadán V.

    2018-03-01

    Full Text Available En este artículo se discuten los resultados del trabajo realizado en el sitio Guiñayzhu, al suroeste de los Andes del Ecuador. Esta investigación revela que el sitio, además de presentar evidencias de poblaciones locales, tiene colcas o qullcas para el almacenaje de productos, terrazas de pirca y caminos empedrados entre otras instalaciones. Se interpreta que Guiñayzhu es uno de los sitios de la cordillera de Chilla que refleja la expansión del incario y expresa una efectiva dominación de esta región como un enclave estratégico del imperio en su avance hacia el norte. ENGLISH: In this article, the results of research carried out in Guiñayzhu, located at the southwest of the Andes of Ecuador, are discussed. This work reveals that in addition to presenting evidence of local populations, the site has colcas or qullqas for the storage of products, terraces of pirca, and roads paved with stone, among other constructions. Guiñayzhu is interpreted as one of the sites of the Chilla mountain range that reflects the expansion of the Inca and expresses an effective domination of this region, representing a strategic enclave of the empire in its advance northward.

  13. La ingeniería y el descarte artefactual de la desalación solar de agua : las industrias de Las Salinas, Sierra Gorda y Oficina Domeyko (1872-1907)

    OpenAIRE

    Arellano-Escudero, Nelson

    2015-01-01

    In the nineteenth century, at the Atacama Desert, a phenomenon of competition occurred between different industrial water desalination techniques, one of which had excellent results and a long life using solar energy. It is a significant fact that this technology was distributed and used in several places in the same desert, when its existence and / or results were diffused in London, New York, Madrid and Santiago de Chile. Nevertheless it seems no to be known in other parts of world befor...

  14. El Transporte Terrestre a través de la Cordillera Cantábrica en Tiempos de Felipe II. Un Estudio a partir de la Correspondencia de Simón Ruiz con Laredo The ground transportation through the Cantabrian Mountains in times of Felipe II. A paper from correspondence of Simón Ruiz with Laredo

    Directory of Open Access Journals (Sweden)

    Oscar LUCAS VILLANUEVA

    2012-12-01

    Full Text Available El presente trabajo analiza las condiciones y costes del transporte terrestre en tiempos de Felipe II en el ámbito de las relaciones comerciales entre Castilla y el espacio atlántico septentrional, a partir de la información proporcionada por las cartas comerciales del mercader Simón Ruiz. Los datos nos indican que las dificultades geográficas no fueron tan determinantes para el tráfico a través de la Cordillera Cantábrica como se había pensado hasta ahora. El artículo también aborda la cuestión de los costes que comportaban las operaciones de traslado de mercancías desde los puertos a los mercados del interior peninsular. Las fuentes nos permiten un detallado análisis de los mismos así como un cálculo de su cuantía en proporción a la suma total de la operación, relativizando la importancia de los mismos, lo que favorecería los traslados de mercancías por vía terrestre para distancias relativamente grandes.This paper analyzes the conditions and cost of ground transportation in times of Felipe II in the field of commercial between Castile and the North Atlantic area, based on information provided by the business letters belonging the merchant Simón Ruiz. The data indicate that the geographical difficulties were not as decisive for the traffic through the Cantabrian Mountains range as it had been thought so far. The article also deals with the subject of the costs that moving goods from ports to inland markets entailed. The sources make it possible a detailed analysis of those cost as well as an estimate of the amount in proportion to the total sum of the operation, giving less importance to them, which would help ground transportation of goods for relatively long distances.

  15. Reproductive and population parameters of Thais chocolata (Duclos, 1832) (Gastropoda, Thaididae) in La Rinconada marine reserve, Antofagasta, Chile/ Parametros reproductivos y poblacionales de Thais chocolata (Duclos, 1832) (Gastropoda, Thaididae), en la reserva marina La Rinconada, Antofagasta, Chile

    National Research Council Canada - National Science Library

    Cantillanez, Marcela; Avendano, Miguel; Rojo, Manuel; Olivares, Alberto

    2011-01-01

    ... Aulacomya ater, Tagelus dombeii, y el caracol carnivoro Thais chocolata (Ortiz et al., 2009a). Estudios recientes han demostrado que el area de la reserva marina que ocupa una superficie de 350 ha, esta sujeta a flujos alternados de corriente que resultan en una corriente predominante dirigida hacia el norte, pero que se encuentra con la barrera impues...

  16. Mixed bird flocks: patterns of activity and species composition in a region of the Central Andes of Colombia Bandadas mixtas de aves: patrones de actividad y composición de especies en una región de la Cordillera Central de los Andes de Colombia

    Directory of Open Access Journals (Sweden)

    Enrique Arbeláez-Cortés

    2011-06-01

    Full Text Available Mixed bird flocks are groups of individuals from different species that travel and forage together. Such groups are common in several bird communities around the world. We present species composition and activity patterns of mixed bird flocks in a region of the Central Andes of Colombia. We compared the number of species per flock, as well as the number of flocks among 3 different habitats. We tested hypotheses concerning the flocks daily activity and the co-occurrences of species within them. We recorded 75 species, and the species number per flock varied from 4 to 21. Our data suggest that habitat affects the number of flocks but not their species number, and that the activity of flocks is similar throughout the day. In addition, the association of birds in flocks is affected by interspecific facilitation, with some species co-occurrences found more times than expected by chance. We hypothesize that some tanager species could have a role in flock cohesion. We witnessed 2 predator attacks upon flocks, a number of agonistic interactions among flock members, and squirrels following bird flocks. Our results meet some general patterns described for mixed bird flocks.Las bandadas mixtas de aves son grupos de individuos de diferentes especies que viajan y forrajean juntos, y son comunes en varias comunidades de aves alrededor del mundo. Presentamos la composición de especies y los patrones de actividad de las bandadas mixtas de aves en una región de la Cordillera Central de los Andes Colombianos. Comparamos el número de especies por bandada y el número de bandadas en 3 hábitats distintos. Evaluamos hipótesis relacionadas con la actividad de las bandadas durante el día y la presencia simultánea de especies en estos grupos. Observamos 75 especies, y el número de especies por bandada varió entre 4 y 21. Nuestros datos indican que el hábitat parece afectar el número de bandadas pero no su número de especies y que la actividad de las bandadas

  17. Seedling density according to structure, dominance and understory cover in old-growth forest stands of the evergreen forest type in the coastal range of Chile Densidad de plántulas de acuerdo a la estructura, dominancia y cobertura del sotobosque en bosques siempreverdes adultos en la cordillera de la Costa de Chile

    Directory of Open Access Journals (Sweden)

    Pablo J. Donoso

    2005-03-01

    distribución del tipo forestal siempreverde en Chile. Sin embargo, las variables de rodal que puedan afectar el establecimiento de regeneración avanzada no se han estudiado. En este estudio se evaluaron siete rodales de la cordillera de la Costa, en la parte norte de la distribución del tipo forestal (39°14'-40°16' S. En ellos se midió la densidad de árboles, plántulas y brinzales, y se estimó la cobertura de copas de los árboles así como del sotobosque, con la finalidad de evaluar los efectos de la dominancia, la estructura y la cobertura del sotobosque sobre la densidad de plántulas de especies forestales. Laurelia philippiana fue la especie dominante a nivel arbóreo y de plántulas. El número de plántulas fue en general significativamente más abundante a altitudes menores donde Aextoxicon punctatum fue importante. Chusquea spp. y Lophosoria quadripinnata, ambas especies del sotobosque, tuvieron un efecto negativo significativo en la densidad de plántulas. El área basal y la cobertura de copas mostraron una pobre relación con la densidad de plántulas. La estructura vertical, evaluada a través del índice de copas, tuvo una relación significativa con la densidad de plántulas, pero su dirección dependió de la especie (i.e., L. philippiana y A. punctatum y la estructura de diámetros de las parcelas. Los modelos ajustados con estas variables fueron altamente significativos, y en la mayoría de los casos su significancia aumentó considerablemente (14 a 26 % cuando se ajustaron separadamente para parcelas con distintas estructuras diamétricas

  18. Deformación andina en el cordón del Hielo Azul al oeste de El Bolsón: Implicancias en la evolución tectónica de la Cordillera Norpatagónica en Río Negro, Argentina Andean deformation at the Cordón del Hielo Azul, El Bolsón, Río Negro (Argentina: Implications for the tectonic evolution of the North Patagonian Andes

    Directory of Open Access Journals (Sweden)

    Jonathan E Tobal

    2012-09-01

    Full Text Available Estudios geológicos de campo realizados en el cordón del Hielo Azul, al oeste de la localidad de El Bolsón, a los 42°S en la Cordillera Norpatagónica (provincia de Río Negro, Argentina, permitieron establecer las distintas relaciones de contacto existentes entre las rocas volcanosedimentarias cordilleranas del Jurásico Inferior, las plutonitas del Batolito Patagónico Cordillerano del Jurásico Medio Superior y las volcanitas cenozoicas de la Formación Ventana. El análisis estructural de las unidades aflorantes mencionadas permitió identificar varias estructuras de deformación previamente desconocidas en este sector de los Andes. Se observó que las rocas volcánicas jurásicas que afloran en el cerro Lindo, al oeste de El Bolsón, se encuentran limitadas por un retrocorrimiento al este y un corrimiento fuera de secuencia al oeste; además se hallan afectadas por dos corrimientos, a los que se asocian estructuras plegadas de menor orden. Al norte, en el cerro Hielo Azul, se observó que las volcanitas jurásicas en su sector occidental se encuentran en contacto tectónico con las volcanitas de la Formación Ventana. Las observaciones de campo permiten inferir la existencia de una falla extensional que controló la depositación de las volcanitas cenozoicas, la cual habría sido luego invertida, sobreponiendo estas rocas a las volcanitas jurásicas. Las distintas fallas reconocidas ejercieron un control de primer orden en el proceso de estructuración del frente montañoso y son, por lo tanto, importantes para comprender el marco tectónico y el levantamiento de la Cordillera Norpatagónica. Se interpreta que la deformación tuvo lugar entre en el Eoceno y el Mioceno Tardío. Un pulso contraccional preoligoceno dio lugar al desarrollo de una faja plegada y corrida de piel fina que afectó a las volcanitas jurásicas. Durante el Oligoceno tuvo lugar un evento extensional de escala regional que dio lugar a la formación de depocentros

  19. Distribución, ecología y origen de las poblaciones de Vitrina pellucida (O. F. Müller, 1774 y Cepaea nemoralis (Linnaeus, 1758 (Gastropoda, Stylommatophora en las Cordilleras Béticas Orientales (Andalucía, España

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    Arrebola, J. R.

    2000-12-01

    'année (zones humides, que les écosystèmes secs de haute montagne, profitant de leur climat froid. En revanche, Cepaea nemoralis (sténotherme occupe seulement les habitats de sols humides, de couverture végétale dense et constante, a une altitude inférieure à 1500 m. L'absence de ce type de végétation et les conditions climatiques dures de la haute montagne méditerranéenne empêchent sa présence à une plus haute altitude, contrairement a ce qui se passe dans la haute montagne euro-sibérienne.
    [es]
    A partir del estudio de la corología y ecología de la malacofauna terrestre de Andalucía (sur de la Península Ibérica se determina la presencia en las cordilleras Bélicas Orientales de dos relictos climáticos propios de la región Eurosiberiana: Vitrina pellucida (O. F. Millier, 1774 y Cepaea nemoralis (Linnaeus, 1758. Se expone su ecología y distribución y se muestra que el principal factor que las limita es la sequía estival característica del clima mediterráneo. Sus respuestas adaptativas ante la escasez de agua del verano están definidas por diferencias ecofisiológicas. Vitrina pellucida (euriterma hace uso tanto de los ecosistemas de tierras bajas en los que la disponibilidad de agua es constante a lo largo del año (zonas húmedas como de los secos de alta montaña, gracias al clima frío. Cepaea nemoralis (estenoterma ocupa sólo hábitats de suelos húmedos y cobertura vegetal densa y constante situados por debajo de los 1500 m. La ausencia de este tipo de vegetación y la dureza del clima de la alta montaña mediterránea impiden su presencia a mayor altitud, al contrario de lo que ocurre en las montarías eurosiberianas.

  20. Paleomagnetic evidence for rotation in the Precordillera of northern Chile: structural constraints and implications for the evolution of the Andean forearc

    Science.gov (United States)

    Hartley, A. J.; Jolley, E. J.; Turner, P.

    1992-04-01

    Palaeomagnetic results are reported for two late Mesozoic to early Cenozoic continental sedimentary sequences from the Precordillera (Cordillera de Domeyko) of northern Chile. Comparison of isolated components of magnetisation from the Late Cretaceous-Palaeocene Purilactis Formation and the unconformably overlying Oligo-Miocene Paciencia Group with reference poles for South America indicate that significant post-Palaeocene and post-Lower Miocene clockwise rotation has taken place. A structural study of the area has revealed the presence of a number of thrust sheets that were periodically active throughout the Cenozoic. Stratigraphie, structural and palaeomagnetic data indicate that thrust sheet movement took place following deposition of both the Purilactis Formation (?lower Eocene Incaic Orogeny) and the Paciencia Group (?lowest Miocene Peheunche Orogeny) and resulted in the folding, uplift and clockwise rotation of the two sequences. Differences in the amount of rotation between the two units reflect incremental movement of the thrust sheets, 12° of rotation took place prior to deposition of the Paciencia Group followed by 17° of post-Lower Miocene clockwise rotation. This study demonstrates that palaeomagnetically detected rotation in the Precordillera of northern Chile, 250 km inland of the Peru-Chile trench, is related to the periodic movement of an easterly propagating thin-skinned thrust front. Between 22°30' and 23°30'S the north Chilean forearc contains areas of non-rotation, thin-skinned compressional related rotations and large, block fault rotations indicating that the simplistic models previously presented to account for forearc rotation in the Central Andes should be modified. In particular, evidence implies that rotation could be related to a number of tectonic events and may not simply be due to one deformation event.

  1. Weighing the Oligocene extensional event in the Salar de Atacama Basin by analysis of depth-converted sections and geophysical data.

    Science.gov (United States)

    Bascunan, S. A.; Maksymowicz, A.; Martínez, F.; Becerra, J.; Rubilar, J. F.; Arriagada, C.; Peña Gomez, M. A.; Gómez, I.

    2016-12-01

    Multiple studies of industry seismic lines across the Salar de Atacama Basin, in the Central Andes of northern Chile (22°-24°S), have led to opposite interpretations regarding its internal architecture, particularly for the Cenozoic successions. These differences can be attributed to the yet uncertain stratigraphy of the 5425 m-deep Toconao-1 well, its relation to outcrops around the El Bordo Escarpment, the tie between the well and the seismic lines, and the lack of a depth conversion of these lines. An analysis of these data allows for the proper location in the depth domain of the most important reflectors found in line Z-1G010, which intersects the borehole. The vertical seismic profile and the density log show that the most significant change in lithological properties occurs at ca. 1 s TWT (1580 m), at the transition from mainly evaporitic deposits to more clastic units, presumably belonging to the Loma Amarilla Formation. This modification in velocity and density can be seen in the seismic line as a major west-dipping surface, dubbed the San Pedro Reflector (SPR). The use of 3D software and the depth conversion allow following the SPR along most of the basin. The surface shows an east-to-west, south-to-north increase in depth, reaching a maximum close to 8 km. The geometry of the surface closely follows the trend of the El Bordo Escarpment. Based on paleomagnetic data, recent mapping and geochronology data, the reflector is estimated to have formed during the Oligocene. Additional extensional features confirm its origin due to small-scale collapse of the Cordillera de Domeyko after the Eocene Incaic Event, after which the deformation front migrated eastwards, thus explaining the presence of extension and compression along the margin at the same time. This change in stress state also affected other parts of the range, such as the Calama Basin.

  2. Mercado laboral femenino. Un estudio empírico, desde la perspectiva de la demanda, en la región minera de Antofagasta, Chile

    Directory of Open Access Journals (Sweden)

    Paulina Salinas

    2010-12-01

    Full Text Available El presente estudio –producto de una investigación realizada en el mercado laboral de la Región de Antofagasta–, examina la baja participación de las mujeres en la zona y describe los factores asociados a esta situación. El análisis de los resultados se realizó con base en los discursos de 87 trabajadoras (asalariadas o microempresarias de distintos sectores laborales de la región; se identifican los obstáculos para acceder al mercado, las razones del repliegue de este sector y las medidas que revertirían esta condición. Este estudio corrobora los resultados obtenidos por investigaciones anteriores, y concluye que, a pesar del crecimiento económico de la zona, los factores asociados a este fenómeno se relacionan con la condición minera de la región, la insuficiente capacitación para el empleo, la incompatibilidad entre los roles productivos y reproductivos, las menores oportunidades y la discriminación de género, todas variables de carácter estructural, cultural e institucional.

  3. Continuidades e hiatos ocupacionales durante el holoceno medio en el borde oriental de la puna salada, Antofagasta de la Sierra, Argentina

    National Research Council Canada - National Science Library

    Pintar, Elizabeth

    2014-01-01

    ...) durante el Holoceno Medio, un periodo de aridez generalizada en toda la Puna. Esta cueva fue un espacio optimo donde grupos cazadores- recolectores realizaron actividades de subsistencia (caza y recoleccion...

  4. BANCO DE SEMILLAS EN UN BOSQUE DE ROBLE DE LA CORDILLERA CENTRAL COLOMBIANA SOIL SEED BANK IN AN OAK FOREST FROM THE COLOMBIAN CENTRAL CORDILLERA

    Directory of Open Access Journals (Sweden)

    Luz Bibiana Moscoso Marín

    2005-12-01

    Full Text Available El banco de semillas del suelo es importante para el funcionamiento del ecosistema, pues se constituye en un reservorio de especies listas a germinar cuando se presenta una perturbación o cuando las condiciones ambientales cambian para iniciar el proceso de sucesión. El objetivo principal de esta investigación fue evaluar la variación espacial del banco de semillas y su relación con la vegetación actual en un fragmento de bosque altoandino dominado por roble de tierra fría (Quercus humbodtii Bonpl. a 2.290 m.s.n.m. en la cuenca de la Quebrada Piedras Blancas, en el departamento de Antioquia, Colombia. Allí se estableció una parcela de 6.400 m², donde se eligieron 57 puntos de muestreo. En cada uno de ellos se colectó una muestra de hojarasca y una de suelo. Además se marcaron cinco subparcelas de 160 m²para hacer el muestreo de la vegetación. La determinación del banco de semillas se hizo por el método de germinación directa, evaluando la emergencia de plántulas. En total, se censaron 204 individuos pertenecientes a 25 familias y 41 géneros. Las especies con mayor representación fueron Alfaroa cf. colombiana, Myrcia popayanensis Rich. y Quercus humboldtii Bonpl. En el ensayo de germinación se obtuvieron 428 individuos en las muestras de suelo y 113 en las de hojarasca, pertenecientes a 20 morfoespecies. La composición de especies del banco de semillas de este fragmento de robledal, no reflejó la composición actual de la vegetación del bosque. El banco de semillas esta constituido principalmente por especies herbáceas y en menor proporción por arbustos. La hojarasca contiene poca cantidad de semillas (198 semillas m-2 y en los primeros 10 cm del suelo se acumula una gran cantidad de semillas viables (4.330 semillas m-2. Se presenta una variación espacial significativa en la densidad de semillas del suelo a través del bosque a escala de unos pocos metros.Soil seed banks are important for ecosystem functioning because they stores species ready to germinate when a perturbation occurs or when environmental conditions change to start the successional process. The main objective of this research was to evaluate the spatial variation of seed banks and its relation with the current vegetation in a highland Andean forest dominated by oak (Quercus humbodtii Bonpl. at 2.290 m.a.s.l. in the watershed of the Piedras Blancas stream, in the department of Antioquia, Colombia. We sampled 57 points in a 6.400 m² plot established in that forest. In each point we collected one sample each of litter and soil. We also established five subplots of 160 m²each for sampling vegetation. Seed banks were assessed by the method of direct germination. We obtained 204 trees belonging to 25 families and 41 genera. The most representative tree species were Alfaroa cf. colombiana, Myrcia popayanensis Rich. and Quercus humboldtii Bonpl. We obtained 428 individuals from soil samples and 113 individuals from litter samples in the germination trial, belonging to 20 morpho species. Species composition of the soil seed bank did not reflect the composition of the forest vegetation, and we found mainly herbaceous and shrub vegetation. Litter had 198 seeds m-2 and soil had 4.330 seeds m-2. There was large spatial variation in the amount of seeds in this forest fragment.

  5. Recent evolution and degradation of the bent Jatunraju glacier (Cordillera Blanca, Peru)

    Czech Academy of Sciences Publication Activity Database

    Emmer, A.; Loarte, E.C.; Klimeš, Jan; Vilímek, V.

    2015-01-01

    Roč. 228, JAN 1 (2015), s. 345-355 ISSN 0169-555X R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : debris-covered glacier * rock glacier * surface movements * buried ice degradation * supraglacial lakes Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 2.813, year: 2015

  6. The Agost Basin (Betic Cordillera, Alicante province, Spain): a pull-apart basin involving salt tectonics

    Science.gov (United States)

    Martín-Martín, Manuel; Estévez, Antonio; Martín-Rojas, Ivan; Guerrera, Francesco; Alcalá, Francisco J.; Serrano, Francisco; Tramontana, Mario

    2017-08-01

    The Agost Basin is characterized by a Miocene-Quaternary shallow marine and continental infilling controlled by the evolution of several curvilinear faults involving salt tectonics derived from Triassic rocks. From the Serravallian on, the area experienced a horizontal maximum compression with a rotation of the maximum stress axis from E-W to N-S. The resulting deformation gave rise to a strike-slip fault whose evolution is characterized progressively by three stages: (1) stepover/releasing bend with a dextral motion of blocks; (2) very close to pure horizontal compression; and (3) restraining bend with a sinistral movement of blocks. In particular, after an incipient fracturing stage, faults generated a pull-apart basin with terraced sidewall fault and graben subzones developed in the context of a dextral stepover during the lower part of late Miocene p.p. The occurrence of Triassic shales and evaporites played a fundamental role in the tectonic evolution of the study area. The salty material flowed along faults during this stage generating salt walls in root zones and salt push-up structures at the surface. During the purely compressive stage (middle part of late Miocene p.p.) the salt walls were squeezed to form extrusive mushroom-like structures. The large amount of clayish and salty material that surfaced was rapidly eroded and deposited into the basin, generating prograding fan clinoforms. The occurrence of shales and evaporites (both in the margins of the basin and in the proper infilling) favored folding of basin deposits, faulting, and the formation of rising blocks. Later, in the last stage (upper part of late Miocene p.p.), the area was affected by sinistral restraining conditions and faults must have bent to their current shape. The progressive folding of the basin and deformation of margins changed the supply points and finally caused the end of deposition and the beginning of the current erosive systems. On the basis of the interdisciplinary results, the Agost Basin can be considered a key case of the interference between salt tectonics and the evolution of strike-slip fault zones. The reconstructed model has been compared with several scaled sandbox analogical models and with some natural pull-apart basins.

  7. Chemical characterization of fog and rain water collected at the eastern Andes cordillera

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    E. Beiderwieden

    2005-01-01

    Full Text Available During a three month period in 2003 and 2004, the chemistry of fog and rainwater were studied at the 'El Tiro' site in a tropical mountain forest ecosystem in Ecuador, South America. The fogwater samples were collected using a passive fog collector, and for the rain water, a standard rain sampler was employed. For all samples, electric conductivity, pH, and the concentrations of NH4+, K+, Na+, Ca2+, Mg2+, Cl−, NO3−, PO43−, and SO42− were measured. For each fog sample, a 5 day back trajectory was calculated by the use of the HYSPLIT model. Two types of trajectories occurred. One type was characterized by advection of air masses from the East over the Amazonian basin, the other trajectory arrived one from the West after significant travel time over the Pacific Ocean. We found considerably higher ion concentrations in fogwater samples than in rain samples. Median pH values are 4.58 for fog water, and 5.26 for the rain samples, respectively. The median electric conductivity was 23 μS cm−1 for the fog and 6 μS cm−1 for the rain. The continent samples exhibit higher concentrations of most ions as compared to the pacific samples, but these differences could not be detected statistically.

  8. ABEJAS SIN AGUIJÓN (Hymenoptera: Apidae: Meliponini EN CEMENTERIOS DE LA CORDILLERA ORIENTAL DE COLOMBIA

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    GUIOMAR NATES-PARRA

    2006-01-01

    Full Text Available Se encontraron 203 nidos de abejas sin aguijón pertenecientes a 15 especies en 11 ce- menterios de los departamentos de Cundinamarca y Meta (Colombia. El 61% de los nidos encontrados pertenecen a abejas del género Nannotrigona Cokerell, 1922. La es- pecie con el mayor número de nidos y mayor representatividad en los cementerios es- tudiados fue Nannotrigona mellaria; Trigona (Tetragonisca angustula se encontró en todos los cementerios estudiados pero, en un porcentaje menor que N. mellaria (29% del to- tal. La densidad máxima encontrada fue de 118 nidos/ha, con un porcentaje de ocu- pación de las tumbas de 13,9% en el cementerio de Tena (Cundinamarca. Se discute sobre la importancia de los cementerios como alternativa para conservación de los sitios de nidificación para abejas silvestres en áreas urbanas.

  9. Sulphide and sulphosalt mineralogy and paragenesis from the Sierra Almagrera veins, Betic Cordillera (SE Spain

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    Martínez Frías, J.

    1991-12-01

    Full Text Available The Sierra Almagrera vein-type mineralization contains base metal sulphides and Pb-Sb- Cu-Ag sulphosalts. The sulphides possess significant proportions of Ag, Sb (galena, Fe (sphalerite and Sb, Zn (chalcopyrite. Ore microscopy and electron microprobe have revealed a mineralogical and textural variation and confirmed the presence of bournonite, boulangerite and anomalous tetrahedrite. The average sulphosalt formulas are bournonite Cu0.98 Pb0. 96 Sb0.98 S3.04, boulangerite Pb4.8Sb3.8S11.34 and anomalous tetrahedrite Ag0.6Cu9.7 Zn3.6 Fe0. 44 Sb3.47 S13- The sequence of mineral deposition indicates the existance of four mineralizing stages and one supergene alteration: 1 Fe-(As; 2 Zn-Cu-Fe; 3 Pb-Sb-Cu-Ag; 4 Cu-Zn-Fe, and 5 carbonates, sulphates and supergene oxides. In broad terms, it is possible to establish the following conclusions: a there exist a mineralogical and textural variation with depth, the Pb-Sb-Cu-Ag stage reaching the maximum development; b a temperature decrease during the formation of sph. 1, linked to the progressive increase in Fe-content of the sphalerite has been detected; c the compositional homogeneity of the bournonite (and the fair lack of As in the tetrahedrite could indicate the existance of a possible tendancy to individually crystallise the Sb and As sulphosalts, according to the trend Bi → Sb → As.La mineralización filoniana de Sierra Almagrera presenta una interesante paragénesis caracterizada por la presencia de sulfuros de metales base y sulfosales de Pb-Sb-Cu-Ag. Se ha identificado una secuencialidad textural y química de las distintas fases minerales, según la cual los sulfuros poseen variaciones significativas de las proporciones de Ag, Sb (galena, Fe (esfalerita, y Sb, Zn (calcopirita, yen la que las sulfosales son fundamentalmente sulfoantimoniuros (bournonita: Cu0.98 Pb0. 96 Sb0.98 S3.04, boulangerita Pb4.8Sb3.8S11.34 y tetraedrita anómala Ag0.6Cu9.7 Zn3.6 Fe0. 44 Sb3.47 S13-. La secuencia de deposición mineral indica la existencia de cuatro etapas de mineralización y una de alteración supergénica: 1 Fe-(As; 2 Zn-Cu-Fe; 3 Pb-Sb-Cu-Ag; 4 Cu-Zn-Fe, y 5 carbonatos, sulfatos y óxidos supergénicos. De acuerdo con los datos obtenidos, se ha establecido que: a existe una variación mineralógica y textural con la profundidad, siendo la tercera etapa mineralizadora la que alcanza un mayor desarrollo; b se observa un decrecimiento de la temperatura (probablemente sin variación de presión, durante la formación de la esfalerita de primera generación (sph.I, atendiendo al incremento progresivo de su contenido en hierro, y c la homogeneidad composicional de la bournonita (junto con la ausencia de arsénico en la tetraedrita, podría indicar una tendencia de cristalización individualizada de las fases de Sb y As, de acuerdo con la tendencia normal: Bi → Sb → As.

  10. Observaciones fitoecológicas en varias regiones de vida de la Cordillera Central de Colombia

    Directory of Open Access Journals (Sweden)

    Rangel Ch. Orlando

    1985-09-01

    Full Text Available En Colombia la confluencia e interacción de una serie de características bióticas y abióticas se manifiestan en una variada disposición de formas y paisajes que se suceden uno tras otro y hacen posible que de su atenta observación se obtengan buenas aproximaciones al caracterizar la ecología regional, especialmente en la extensa zona andina (CUATRECASAS,1934, 1958, 1959a; GUHL, 1974; MURILLO, 1951.La situación anteriorrnente -expuesta, permite adelantar en excursiones de corta duración, trabajos de tipificación ecológica en las biocenosis existentes en un gradiente altitudinal apropiado.Los resultados corresponden a una de estas excursiones llevada a cabo entre el 10 de septiernbre y el 5 de octubre de 1980, en particular los references a las comunidades vegetales tipificadas en dos transectos que tomando como referencia central el Municipio de La Plata (Huila, van en dirección Nor-Occidental Irlanda-Santo Domingo (carretera Tóez-Tacueyó y Sur-Occidental reserva de Merenberg-Laguna de San Rafael (Purace

  11. Tectonic processes during oblique collision: Insights from the St. Elias orogen, northern North American Cordillera

    Science.gov (United States)

    Pavlis, T.L.; Picornell, C.; Serpa, L.; Bruhn, R.L.; Plafker, G.

    2004-01-01

    Oblique convergence in the St. Elias orogen of southern Alaska and northwestern Canada has constructed the world's highest coastal mountain range and is the principal driver constructing all of the high topography in northern North America. The orogen originated when the Yakutat terrane was excised from the Cordilleran margin and was transported along margin-parallel strike-slip faults into the subduction-transform transition at the eastern end of the Aleutian trench. We examine the last 3 m.y. of this collision through an analysis of Euler poles for motion of the Yakutat microplate with respect to North America and the Pacific. This analysis indicates a Yakutat-Pacific pole near the present southern triple junction of the microplate and' predicts convergence to dextral-oblique convergence across the offshore Transition fault, onland structures adjacent to the Yakutat foreland, or both, with plate speeds increasing from 10 to 30 mm/yr from southeast to northwest. Reconstructions based on these poles show that NNW transport of the collided block into the NE trending subduction zone forced contraction of EW line elements as the collided block was driven into the subduction-transform transition. This suggests the collided block was constricted as it was driven into the transition. Constriction provides an explanation for observed vertical axis refolding of both earlier formed fold-thrust systems and the collisional suture at the top of the fold-thrust stack. We also suggest that this motion was partially accommodated by lateral extrusion of the western portion of the orogen toward the Aleutian trench. Important questions remain regarding which structures accommodated parts of this motion. The Transition fault may have accommodated much of the Yakutat-Pacific convergence on the basis of our analysis and previous interpretations of GPS-based geodetic data. Nonetheless, it is locally overlapped by up to 800 m of undeformed sediment, yet elsewhere shows evidence of young deformation. This contradiction could be produced if the overlapping sediments are too young to have accumulated significant deformation, or GPS motions may be deflected by transient strains or strains from poorly understood fault interactions. In either case, more data are needed to resolve the paradox. Copyright 2004 by the American Geophysical Union.

  12. Experiences de cordillera, ecos de frio: relatos cruzados entre Chile y Quito en el siglo XVI

    National Research Council Canada - National Science Library

    Vega, Alejandra

    2011-01-01

    .... En primer lugar, se despliegan proximas en el tiempo y parecen ser el resultado directo de la circulacion de noticias acerca del legendario reparto de Cajamarca y el consiguiente deseo de participar en los beneficios de la conquista del Peru. No obstante, se trata de expediciones "fracasadas" en el sentido de que ninguna logra consolidar posiciones territ...

  13. Transcurrent tectonics and melange in the Sierra Arana area (Betic Cordillera, NE of Granada)

    Energy Technology Data Exchange (ETDEWEB)

    Sanz de Galdeano, C.; Lopez Garrido, A.C.

    2016-07-01

    In the Sierra Arana area, dextral transcurrent faults form a set of long and narrow E-W tectonic bands, some of which are filled by Oligo-Aquitanian and Cretaceous sediments deeply squeezed among Jurassic carbonates. These bands form a “flower structure” which higher blocks, cut by the faults, fallen over Oligo-Aquitanian sediments, forming a tectonic mélange. The crest zone of Sierra Arana indicates the position of a great reversed south verging anticlinal. The elements situated directly to the south of Sierra Arana, are attributed to a very internal Subbetic or to the Dorsal, and seem to correspond to the paleogeographic passage from the Subbetic to the Malaguide Complex. (Author)

  14. Effect of the Andes Cordillera on Precipitation from a Midlatitude Cold Front

    Science.gov (United States)

    2009-09-01

    collective comments and suggestions have greatly improved the manuscript. We also thank Direccion de Aguas of Chile, and Mr. Dan Dawson of the...L. F. Bosart, and G. W. Endersen, 1976: An ex- amination of the frequency and mean conditions surrounding frontal incursions into the Gulf of Mexico

  15. Two sympatric new species of woodlizards (Hoplocercinae, Enyalioides) from Cordillera Azul National Park in northeastern Peru

    Science.gov (United States)

    Venegas, Pablo J.; Torres-Carvajal, Omar; Duran, Vilma; de Queiroz, Kevin

    2013-01-01

    Abstract We report the discovery of two sympatric new species of Enyalioides from a montane rainforest of the Río Huallaga basin in northeastern Peru. Among other characters, the first new species is distinguishable from other Enyalioides by the combination of the following characters: strongly keeled ventral scales, more than 37 longitudinal rows of dorsals in a transverse line between the dorsolateral crests at midbody, low vertebral crest on the neck with vertebrals on neck similar in size to those between hind limbs, projecting scales on body or limbs absent, 96 mm maximum SVL in both sexes, and caudals increasing in size posteriorly within each autotomic segment. The second new species differs from other species of Enyalioides in having strongly keeled ventral scales, scales posterior to the superciliaries forming a longitudinal row of strongly projecting scales across the lateral edge of the skull roof in adults of both sexes, 31 or fewer longitudinal rows of strongly keeled dorsals in a transverse line between the dorsolateral crests at midbody, vertebrals on neck more than five times the size of vertebrals between hind limbs in adult males, projecting scales on body or limbs absent, and caudals increasing in size posteriorly within each autotomic segment. We also present an updated molecular phylogenetic tree of hoplocercines including new samples of Enyalioides rudolfarndti, Enyalioides rubrigularis, both species described in this paper, as well as an updated identification key for species of Hoplocercinae. PMID:23794824

  16. NEW GEOLOGICAL AND GEOPHYSICAL CONTRIBUTIONS IN THE SECTION IBAGUÉ – ARMENIA, CENTRAL CORDILLERA - COLOMBIA

    Directory of Open Access Journals (Sweden)

    Vargas Carlos A.

    2005-08-01

    Full Text Available Ha sido interpretada la sección geológica entre las ciudades de Ibagué y Armenia basada en observaciones geofísicas y estructurales en busca de establecer el estilo estructural dominante y la configuración del basamento en profundidad. Inicialmente se realizaron mediciones gravimétricas y magnetométricas levantadas cada 500 m entre estas ciudades, las cuales permitieron soportar el desarrollo del experimento sísmico "Armenia-Quake". El alcance del experimento sísmico permitió detectar reflectores hasta aproximadamente 17 km de profundidad en un área de influencia de aproximadamente 25 km. La interpretación integral de la información geológica y geofísica permite concluir que el Complejo Cajamarca define una estructura sinclinal amplia cerca al Municipio de Cajamarca. Partiendo de dicha información se pudo reconocer la presencia de un basamento compuesto por cuñas de rocas basálticas y sedimentarias asociadas a las formaciones Quebradagrande y Arquía. Igualmente se reconoce la existencia de una gran flexión de la paleo-placa oceánica relacionada a la formación Barroso, la cual se encuentra limitada al occidente por la falla Cauca-Almaguer. La estructura en flexión y la evolución compresiva del estado de esfuerzos en esta región de América del Sur podrían ser las responsables del depósito y posterior plegamiento de la formación Cinta de Piedra que constituye en gran medida la Serranía de Santa Bárbara.

  17. Using the Mesozoic History of the Canadian Cordillera as a Case Study in Teaching Plate Tectonics.

    Science.gov (United States)

    Chamberlain, Valerie Elaine

    1989-01-01

    Reviews a model used in the teaching of plate tectonics which includes processes and concepts related to: terranes and the amalgamation of terranes, relative plate motion and oblique subduction, the effects of continent-continent collision, changes in plate motion, plate configuration, and the type of plate boundary. Diagrams are included.…

  18. Biología reproductiva de Eschweilera bogotensis (Lecythidaceae, en la Cordillera Occidental de Colombia

    Directory of Open Access Journals (Sweden)

    Gamboa Gaitán Miguel Ángel

    1997-11-01

    Full Text Available The reproductiva biology of Eschweilera bogotensis (Lecythidaceae was studied in a premontane forest at Los Farallones de Cali National Park (1650 m from november 1993 to march 1994. A great number of insects visit the flowers of this tree. Curculionidae and Nitidulidae (Coleoptera larvae, as well as Cecidomyidae (Diptera larvae feed on immature flowers, while Pyralidae and Blastobasidae (Lepidoptera larvae eat ripening fruits. Adult individual s of Staphylinidae (Coleoptera and Phlaethripidae (Thysanoptera were observed feeding on pollen. Loss of floral buds due to larval parasitism was as high as 70%. Three species of Hymenoptera were identified as visitors: Trigona amalthea, Eulaema meriana (Apidae, and Epicharis rustica (Anthophoridae. The latter was identifiedas the main pollinator. Fruit set per inflorescence is quite low (three max., and over 50% of inflorescences get lost. Seed release is carried out by transversal dehiscence of the fruit, releasing 4-7 seeds. Seed dispersal by animals, which eat part of the peel and seeds, is significant. Bites on the fruits observed in the field suggest that the disperser is a rodent, probably a squirrel, common at the study site. Germination of bitten seeds was observed.Se estudió la biología reproductiva de Eschweilere bogotensis (Lecyhidaceae, en un bosque muy húmedo premontano del Parque Nacional Los Farallones de Cali (1650 m, entre noviembre de 1993 y marzo de 1994. Numerosos insectos visitan las inflorescencias de este árbol. Las larvas de Curculionidae, Nitidulidae (Coleoptera y Cecidomyidae (Diptera depredan flores inmaduras, mientras que las de Pyralidae y Blastobasidae (Lepidoptera depredan frutos maduros. También se observaron adultos de Staphylinidae (Coleoptera, los cuales se alimentan de polen al igual que los Phlaethripidae (Thysanoptera. Las pérdidas de botones florales por parasitismo alcanzaron el 70%. Se identificaron tres especies de himenópteros como visitantes regulares: Trigona amalthea, Eulaema meriana (Apidae y Epicharis rustica (Anthophoridae. Este último es el principal agente polinizador. La fructificación por inflorescencia es muy baja (tres máximo, y más del 50% de las inflorescencias se pierden en su totalidad. La liberación de las semillas se hace mediante dehiscencia transversal del fruto, liberándose de 4 a 7 semillas. La dispersión por animales, los cuales consumen parte de la cáscara y semillas, es significativo. Por las huellas de mordeduras observadas en el campo, se asume que el agente dispersor es un roedor, muy probablemente una ardilla, animal común en la zona. Se ha comprobado la germinación de semillas mordidas.

  19. Constraining Glacial Runoff Contributions to Water Resources in the Cordillera Real, Bolivia using Environmental Tracers

    Science.gov (United States)

    Guido, Z.; McIntosh, J. C.; Papuga, S. A.

    2013-12-01

    Warming temperatures in recent decades have contributed to substantial reductions in glaciers in many mountain regions around the globe, including the South American Andes. Melting of these glaciers taps water resources accumulated in past climates, and the diminishing ice marks a decrease in a nonrenewable water source that begs the question: how will future water supplies be impacted by climate change. Water resource management and climate adaptation efforts can be informed by knowledge of the extent to which glaciers contribute to seasonal streamflows, but remote locations and scant monitoring often limit this quantification. In Bolivia, more than two million people draw water from watersheds fed, in part, by glaciers. The amount to which these glaciers contribute to the water supply, however, is not well constrained. We apply elemental and isotopic tracers in an end-member mixing model to quantify glacial runoff contributions to local water supplies. We present oxygen and deuterium isotopes and major anion concentrations (sulfate and chloride) of shallow groundwater, streams, reservoirs, small arroyos, and glacial runoff. Isotopic and anion mixing models suggest between 45-67% of the water measured in high altitude streams originated from within the glacial footprint during the 2011 wet season, while glacial runoff contributed about 42-53% of the water in reservoirs in the 2012 dry season. Data also show that shallow groundwater is connected to glacial-fed streams. Any future decrease in glacial runoff may contribute to a reduction in surface water supplies and lower groundwater levels downstream, perhaps below the depth of hand-dug wells common in rural communities.

  20. Development of Ideas About Holocene and Latest Pleistocene Glacier Advances in the North American Cordillera

    Science.gov (United States)

    Osborn, G.

    2014-12-01

    It all started when Francois Matthes coined the phrase "little ice age" (LIA) in 1939 to explain cirque moraines in the Sierra Nevada. Porter and Denton in the late 60's promoted the concept that the LIA was part of a multi-millennium regrowth of glaciers called "Neoglaciation."A second set of small moraines found in a few cirques short distances downvalley of LIA moraines in the American Rockies began attracting some attention in the 1940s-50s. By the 1960s-70s there was much argument over the age(s) of these moraines. A proliferation of ages appeared in the literature in the 1970s-80s, but Thom Davis and Jerry Osborn in 1987 proposed that most or all these outer cirque moraines are actually Younger Dryas (YD) in age.In Alberta in the 1970s, Brian Luckman began studying LIA deposits and Osborn began mapping outer cirque moraines (Crowfoot moraines). The two joined forces for an overview of Holocene glacial history in the Canadian Rockies in 1979.Eric Leonard and Mel Reasoner began lake-sediment studies in the Canadian Rockies in the 1980s-90s. Reasoner and Osborn concluded using lake sediments that the type Crowfoot moraine is YD in age, and in Colorado and Wyoming, Davis, Reasoner, and Brian Menounos established YD ages of outer cirque moraines. Lateral-moraine stratigraphy, begun in the 1980s by June Ryder and Osborn in British Columbia, corroborated the evidence from lake sediments that minor advances and retreats punctuated a gradual Neoglacial expansion of glaciers that began 7 or 8 ka.The era of cosmogenic dating began in the 1990s, with John Gosse's work in the Wind River Range. Most, but not all, cosmogenic ages on outer cirque moraines, including those yielded by Shaun Marcott's broad survey, are in support of the concept that such moraines are YD or pre-YD in age, although uncertainties resulting from production-rate questions remain. There have been various claims of early Holocene advances greater in magnitude than the LIA, but these have been dismissed in the literature and have not gained general acceptance.Most recently, Menounos found so-called "monster moraines" well downstream of LIA moraines in northern British Columbia and the Yukon where there are no small Crowfoot-type outer moraines. New dates suggest these monsters are a different manifestation of the YD associated with the decaying Cordilleran Ice Sheet.

  1. Las plantas vasculares de los afloramientos rocosos de Suesca, Cordillera Oriental colombiana

    Directory of Open Access Journals (Sweden)

    Carolina Avellaneda Cadena

    2006-01-01

    Full Text Available Se muestrearon las plantas vasculares presentes en tres tipos de afloramientos rocosos del municipio de Suesca, departamento de Cundinamarca (Colombia, ubicados entre 2.800 y 3.000 m de altitud. Estos sitios se denominaron Valle de los Halcones (VH, Farallones de Suesca (FS y Los Monolitos (LM. Cada planta fue recolectada, determinada y se le anotó la superficie en la que crecía (placa, repisa o fisura y el hábito de crecimiento (erecta, colgante o perpendicular a la superficie. Se encontraron 97 especies, correspondientes a 38 familias y 70 géneros. La familia más diversa fue Asteraceae, seguida de Poaceae, Orchidaceae, Bromeliaceae y Polypodiaceae. El género con más especies fue Tillandsia, seguido de Polypodium. Los sitos de muestreo con mayor diversidad fueron VH y FS. En LM las familias con más especies fueron Asteraceae y Poaceae, en FS Poaceae y Asteraceae y en VH Asteraceae y Orchidaceae. En VH las placas fue la superficie con mayor número de especies, mientras que en LM fueron las repisas y en FS las placas y las repisas. La mayoría de las especies encontradas en todos los sitos fueron erectas, seguidas de las perpendiculares a la superficie. Los tres sitios de muestreo mostraron alta similitud florística entre sí.

  2. Algunos ammonoideos del Calloviense superior de Aguilón (Zaragoza. Cordillera Ibérica

    Directory of Open Access Journals (Sweden)

    Sequeiros, L.

    1984-12-01

    Full Text Available More than 16 detailed biostratigraphical condensed profiles containing Middle/Upper Callovian and Lower Oxfordian ammonite fauna are described nearly Aguilón (Zaragoza. Have been studied more than 300 fossil samples. 75 taxons identified let recognize the Athleta-zone and at least a part of Lamberti-zone, Orbignyceras trezeense document the botton of Athleta-zone, while Mirosphinces, Poculisphinctes and Euasptdoceras ferrugineum show up the Lamberti-zone (Poculum subzone.

    Se describen más de 16 perfiles condensados desde el punto de vista bioestratigráfico con fauna de ammonites de edad Calloviense medio/superior y Oxfordiense inferior en los alrededores de Aguilón (Zaragoza, Se han estudiado más de 300 muestras, identificándose 75 taxones diferentes que permiten reconocer fauna de la zona Athleta y al menos parte. de la zona Lamberti del Callovienese superior. Orbignyceras trezeense documenta la presencia de la base de Athleta, mientras que Mirosphinctes, Poculisphinctes y Euaspidoceras ferrugineum parecen indicar la zona Lamberti (subzona de Poculum.

  3. Rainfall Distribution in Three High Andean Forests in the Central Cordillera of Colombia.

    OpenAIRE

    Juan Diego León Peláez; Maria Isabel González Hernández; Juan Fernando Gallardo Lancho

    2010-01-01

    Se estudió la distribución del agua lluvia durante tres años en un bosque climácico de roble (Quercus humboldtii) y dos plantaciones forestales, de pino (Pinus patula) y ciprés (Cupressus lusitanica) ubicados en los Andes colombianos. Los principales ingresos de agua al bosque ocurrieron por la lluvia, cuyo valor medio anual fue 1.700 mm año-1. La precipitación interna tuvo la mayor participación de los flujos hídricos del bosque, siendo máxima en el cipresal (1.486 mm a-1, 90 %) y mínima en ...

  4. Managing glacier related risks in the Chucchún Catchment, Cordillera Blanca, Peru

    Science.gov (United States)

    Muñoz, Randy; Gonzáles, César; Price, Karen; Frey, Holger; Huggel, Christian; Cochachin, Alejo; García, Javier; Mesa, Luis

    2015-04-01

    On April 11 2010, the city of Carhuaz and settlements in the Chucchún Catchment (Ancash region, Peru) suffered the impact of a glacier lake outburst flood. An avalanche of rock and ice from the Mount Hualcán hit the glacier lake 513, triggering a glacial lake outburst flood (GLOF) of 1 million m3 which destroyed farmland and several infrastructures. Although there was no loss of human life, the event caused panic in the population. In consequence, the Municipality of Carhuaz prioritized GLOF-related risk management. The Glacier Project, funded by Swiss Agency for Development and Cooperation, and executed by CARE Peru and the University of Zurich, fosters the coordination among public institutions (Glaciological Unit of the National Water Authority, the Ministry of Environment and Municipality) and the population for risk management. In this contribution we present all components of the risk management strategy as well as the lessons learned during the implementation. Risk management involves managing both glacier hazard as well as the vulnerability of the population. In this framework a glaciological and geomorphological characterization of Mount Hualcán and lake 513 was perfomed in order to model past and potential future outburst floods and to assess the slope stability conditions. Based on three potential GLOF scenarios of different magnitudes, a hazard map was produced for the entire catchment, which served as the basis for the vulnerability and risk assessment as well as for the design and the implementation of an Early Warning System (EWS), including evacuation planning. The EWS consists of 4 components: 1) knowledge of risk, through hazard and vulnerability characterization; 2) monitoring and alert, through the installation of monitoring stations on lake 513 for detecting avalanches with geophones and cameras; 3) broadcasting and communications, through the implementation of communication protocols between the Municipality of Carhuaz and emergency institutions (police, health centers and schools) and also authorities at higher coordination levels (Regional Government and the National Emergency Operations Center) enabling rapid emergency care; and 4) Responsiveness, through strengthening and training of public and private institutions and local leaders that make up the Civil Defense Platforms, the development of Emergency Operations Plan, and continuous organization of simulations for the population. As result, the population is aware of the risks they face and knok how to respond in case of a lake outburst event. In addition, the results generated during studies related to the risk analysis are used for land management of the Municipality of Carhuaz. The successful implementation of this risk management strategy was only possible by combining comprehensively scientific and local knowledge. This EWS represents a pilot experience in Peru and the Andes, and contributes to relatively scarce international experience with GLOF EWS. An important lesson is that these processes require active leadership of local authorities and continuous learning by the population. The mere existence of technology does not ensure the success of the risk reduction measures; this can only be attained by the internalization of processes and by taking responsibility against the existing hazard by each resident, authority and institution.

  5. The evolution of the Piedemonte Llanero petroleum system, Cordillera Oriental, Colombia (2) Reservoir petrography & petroleum geochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Piggott, N.; Vear, A.; Warren, E.A. [BP Exploration, London (United Kingdom)] [and others

    1996-08-01

    Detailed quantification of cements and rock texture, fluid inclusion microthermometry, thermal maturity data, oil-source rock correlations and structural restorations have been integrated to reveal the porosity and hydrocarbon charge evolution of reservoirs in the Piedemonte Llanero thrustbelt of Colombia. Active exploration of deeply buried structures in different thrust sheets of the Piedemonte Llanero has encountered quartz arenites of widely varying average porosities (4-15%). Porosity has been reduced by mechanical compaction and quartz cementation during burial, and by pressure solution during structural deformation. The relative importance and timing of these processes varies between thrust sheets controlling the observed porosity variation. Thermal maturity data indicate that all thrust sheets have been deeply buried and uplifted in several stages of compression. Detailed structural restorations indicate significant differences in the burial histories of individual thrust sheets. Oil-source rock correlations suggest two major hydrocarbon components in the thrustbelt: a Late Cretaceous oil-prone source and a Tertiary oil- and gas-prone source. Initial generation charged early structures leading to partial inhibition of quartz cementation. For most structures quartz cementation predated major hydrocarbon migration. Average quartz cementation temperature is uniform within a structure, but varies between thrust sheets. These variations appear to reflect differences in burial depths during quartz cementation rather than variations in timing. Integration of all data reveals a complex but predictable evolution of porosity and hydrocarbon charge in both space and time which is being applied to current exploration in the Piedemonte Llanero and is relevant to thrustbelt exploration elsewhere.

  6. Cold seep-related occurrence of the Early Jurassic rhynchonellid brachiopod Anarhynchia from the Canadian Cordillera

    Science.gov (United States)

    Pálfy, József; Price, Gregory D.; Vörös, Attila; Kovács, Zsófia; Johannson, Gary G.

    2017-04-01

    Cold seeps, where seepage of methane and/or other hydrocarbon-rich fluids and hydrogen-sulfide occurs in the sea floor, are sites which harbor highly specialized ecosystems associated with distinctive carbonate sediments. Although their Mesozoic record is scarce and patchy, it commonly includes rhynchonellid brachiopods, often of large size. Each new occurrence is valuable in filling gaps and providing additional insight into these peculiar ecosystems. Here we report a monospecific assemblage of Anarhynchia from a boulder-sized limestone clast of Early Pliensbachian (Early Jurassic) age in the Inklin Formation of the Whitehorse Trough in Stikine terrane, recovered from a locality at Copper Island in Atlin Lake, northern British Columbia, Canada. Specimens are of unusually large size, up to 9 cm in length, and their external and internal morphology allows assignment to Anarhynchia but warrants introduction of a new species. Although d13C and d18O values of the shells are close to equilibrium with ancient seawater, early precipitated carbonate cement phases of the enclosing limestone are characterised by highly depleted carbon isotopic composition, indicative of the influence of microbial oxidation of methane derived from a cold seep. Carbonate petrography of the isopachous, banded-fibrous cement supports its origin in a cold seep environment. Volcanogenic detrital grains in the micritic matrix of the limestone clast are indistinguishable from those in the sandstone layers in the siliciclastic sequence, suggesting that the seep carbonate is broadly coeval with the enclosing conglomerate. Previously, Anarhynchia has been known from the Lower Jurassic of California and Oregon, from both cold seep and hydrothermal vent deposits. Our new record extends the geographic range and species-level diversity of the genus, but supports its endemism to the East Pacific and membership in chemosynthesis-based ecosystems.

  7. Natural and anthropogenic controls on soil erosion in the internal betic Cordillera (southeast Spain)

    NARCIS (Netherlands)

    Bellin, N.; VanAcker, V.; Wesemael, van B.; Solé-Benet, A.; Bakker, M.M.

    2011-01-01

    Soil erosion in southeast Spain is a complex process due to strong interactions between biophysical and human components. Significant progress has been achieved in the understanding of soil hydrological behavior, despite the fact that most investigations were focused on the experimental plot scale.

  8. Las plantas vasculares de los afloramientos rocosos de Suesca, Cordillera Oriental colombiana

    Directory of Open Access Journals (Sweden)

    Betancur Julio César

    2006-06-01

    Full Text Available Se muestrearon las plantas vasculares presentes en tres tipos de afloramientos rocosos del municipio de Suesca, departamento de Cundinamarca (Colombia, ubicados entre 2.800 y 3.000 m de altitud. Estos sitios se denominaron Valle de los Halcones (VH, Farallones de Suesca (FS y Los Monolitos (LM. Cada planta fue recolectada, determinada y se le anotó la superficie en la que crecía (placa, repisa o fisura y el hábito de crecimiento (erecta, colgante o perpendicular a la superficie. Se encontraron 97 especies, correspondientes a 38 familias y 70 géneros. La familia más diversa fue Asteraceae, seguida de Poaceae, Orchidaceae, Bromeliaceae y Polypodiaceae. El género con más especies fue Tillandsia, seguido de Polypodium. Los sitos de muestreo con mayor diversidad fueron VH y FS. En LM las familias con más especies fueron Asteraceae y Poaceae, en FS Poaceae y Asteraceae y en VH Asteraceae y Orchidaceae. En VH las placas fue la superficie con mayor número de especies, mientras que en LM fueron las repisas y en FS las placas y las repisas. La mayoría de las especies encontradas en todos los sitos fueron erectas, seguidas de las perpendiculares a la superficie. Los tres sitios de muestreo mostraron alta similitud florística entre sí.

  9. Two sympatric new species of woodlizards (Hoplocercinae, Enyalioides ) from Cordillera Azul National Park in northeastern Peru.

    Science.gov (United States)

    Venegas, Pablo J; Torres-Carvajal, Omar; Duran, Vilma; de Queiroz, Kevin

    2013-01-01

    We report the discovery of two sympatric new species of Enyalioides from a montane rainforest of the Río Huallaga basin in northeastern Peru. Among other characters, the first new species is distinguishable from other Enyalioides by the combination of the following characters: strongly keeled ventral scales, more than 37 longitudinal rows of dorsals in a transverse line between the dorsolateral crests at midbody, low vertebral crest on the neck with vertebrals on neck similar in size to those between hind limbs, projecting scales on body or limbs absent, 96 mm maximum SVL in both sexes, and caudals increasing in size posteriorly within each autotomic segment. The second new species differs from other species of Enyalioides in having strongly keeled ventral scales, scales posterior to the superciliaries forming a longitudinal row of strongly projecting scales across the lateral edge of the skull roof in adults of both sexes, 31 or fewer longitudinal rows of strongly keeled dorsals in a transverse line between the dorsolateral crests at midbody, vertebrals on neck more than five times the size of vertebrals between hind limbs in adult males, projecting scales on body or limbs absent, and caudals increasing in size posteriorly within each autotomic segment. We also present an updated molecular phylogenetic tree of hoplocercines including new samples of Enyalioides rudolfarndti, Enyalioides rubrigularis, both species described in this paper, as well as an updated identification key for species of Hoplocercinae.

  10. Una nueva especie de saurio para la Cordillera Oriental de Colombia (Sauria; Iguanidae

    Directory of Open Access Journals (Sweden)

    Rueda José Vicente

    1986-12-01

    Full Text Available El grupo de especies referidas al complejo de Anolis tiqrinus constituye un pequeño conjunto autóctono suramericano de distribución muy amplia, incluido dentro de la Sección a de los Anolis, que se caracterizan esencialmente por la ausencia de procesos transversos sobre las vértebras caudales y de septos autotómicos (ETHERIDGE, 1967.

  11. Elastic Wavespeed Images of Northern Chile Subduction Zone from the Joint Inversion of Body and Surface Waves: Structure of the Andean Forearc and the Double Seismic Zone

    Science.gov (United States)

    Comte, D.; Carrizo, D.; Roecker, S. W.; Peyrat, S.; Arriaza, R.; Chi, R. K.; Baeza, S.

    2015-12-01

    Partly in anticipation of an imminent megathrust earthquake, a significant amount of seismic data has been collected over the past several years in northern Chile by local deployments of seismometers. In this study we generate elastic wavespeed images of the crust and upper mantle using a combination of body wave arrival times and surface wave dispersion curves. The body wave data set consists of 130000 P and 108000 S wave arrival times generated by 12000 earthquakes recorded locally over a period of 25 years by networks comprising about 360 stations. The surface wave data set consists of Rayleigh wave dispersion curves determined from ambient noise recorded by 60 broad band stations from three different networks over a period of three years. Transit time biases due to an uneven distribution of noise were estimated using a technique based on that of Yao and van der Hilst (2009) and found to be as high as 5% for some station pairs. We jointly invert the body and surface wave observations to both improve the overall resolution of the crustal images and reduce the trade-off between shallow and deep structures in the images of the subducted slab. Of particular interest in these images are three regions of anomalous Vp/Vs: (1) An extensive zone of low Vp/Vs (1.68) correlates with trench-parallel magmatic belts emplaced in the upper continental crust. In the region of the coast and continental slope, low Vp/Vs corresponds to batholithic structures in the Jurassic-Cretaceous magmatic arc. Between the central depression and Domeyko Cordillera, low Vp/Vs correlates with the distribution of magmatic arcs of Paleocene-Oligocene and Eocene-Oligocene age. Low Vp/Vs also correlates with the location of the Mejillones Peninsula. (2) A region of high Vp/Vs occurs in what is most likely the serpentinized wedge of the subduction zone. (3) An additional zone of low Vp/Vs is located in the middle of the double seismic zone at depths of 90-110 km. This region may exist all along the

  12. Reconversión arquitectónica como respuesta sustentable : la conservación y gestión del patrimonio industrial en la región de Antofagasta, Chile

    OpenAIRE

    Ostria González, Claudio

    2012-01-01

    Programa de Doctorado en Historia del Arte y Gestión Cultural en el Mundo Hispánico La definición del tema y su delimitación, responden a la defensa de un patrimonio, que por sus propios valores como arquitectura, no está suficientemente considerado como tal y donde además de los edificios hay maquinarias, herramientas, instalaciones, procesos productivos, tecno-económicos, sociales e ideológicos, necesarios de preservar, ya que parecen condenados a la destrucción. Por otro lado, se plante...

  13. El sitio Bajo del Coypar II: Las evidencias más tempranas (CA. 1000 AP del proceso agropastoril en la Puna Meridional Argentina (Antofagasta de la Sierra, Catamarca

    Directory of Open Access Journals (Sweden)

    Silvina Vigliani

    2005-01-01

    Full Text Available El sitio Bajo del Coypar II (BC II es un conjunto de estructuras de pequeñas dimensiones ubicado sobre una saliente de la ladera de los cerros del Coypar, frente y alrededor del cual se distribuye una gran superficie de campos de cultivo prehispánicos, (Bajo del Coypar I de aproximadamente 1000 ha. En un trabajo anterior se postuló que este amplio sistema de producción agrícola se originó hacia el final del proceso regional tardío (ca. 1300 AP en asociación con el crecimiento del principal centro habitacional de la región, La Alumbrera (Olivera et.al, 1994 y que luego fue apropiado y ampliado por el Incario. En el presente trabajo se plantean tres objetivos generales: conocer el tipo de actividades que se realizaban en el conjunto de estructuras de BC II, establecer la asociación que había entre este conjunto de estructuras y el sistema de producción agrícola e identificar posibles cambios en el uso del espacio a lo largo del tiempo. En un principio se pensó que Bajo del Coypar II formaba parte de la ampliación del espacio productivo implementada por el Imperio Incaico. Las investigaciones llevadas a cabo en el mismo permitieron determinar que efectivamente hacia las etapas más tardías y en asociación con el Incario había una estrecha relación con el sector agrícola, evidenciado en una alta frecuencia de vasijas para el almacenaje y/o el procesamiento de sustancias secas. Sin embargo, también revelaron ocupaciones más tempranas vinculadas a grupos o unidades domésticas con un desarrollo creciente de las prácticas agrícolas. De este modo, la actividad agro-pastoril fue, en este sector de la Puna meridional, mucho más temprana de lo que pensábamos.

  14. DISTRIBUCIÓN DEL AGUA LLUVIA EN TRES BOSQUES ALTOANDINOS DE LA CORDILLERA CENTRAL DE ANTIOQUIA, COLOMBIA RAINFALL DISTRIBUTION IN THREE HIGH ANDEAN FORESTS IN THE CENTRAL CORDILLERA OF COLOMBIA

    Directory of Open Access Journals (Sweden)

    Juan Diego León Peláez

    2010-06-01

    Full Text Available Se estudió la distribución del agua lluvia durante tres años en un bosque climácico de roble (Quercus humboldtii y dos plantaciones forestales, de pino (Pinus patula y ciprés (Cupressus lusitanica ubicados en los Andes colombianos. Los principales ingresos de agua al bosque ocurrieron por la lluvia, cuyo valor medio anual fue 1.700 mm año-1. La precipitación interna tuvo la mayor participación de los flujos hídricos del bosque, siendo máxima en el cipresal (1.486 mm a-1, 90 % y mínima en el pinar (1.389 mm a-1, 81 %, mientras que el escurrimiento cortical fue muy bajo en los tres bosques (1-3 mm a-1, 0,1-0,2 %. La máxima intercepción se presentó en el pinar (329 mm a-1, equivalente al 19 % de la lluvia. A diferencia de estos flujos hídricos del dosel los flujos hídricos del suelo sí mostraron diferencias significativas entre coberturas (P Rainfall distribution was assessed for three years in a mature oak forest (Quercus humboldtii, pine (Pinus patula and cypress (Cupressus lusitanica plantations in the northern part of the colombian Andean mountains. An annual average of 1700 mm was the main water input in the forests, which came from the bulk precipitation. The higher water flows were represented by throughfall, which showed a maximum value in the cypress (1486 mm y¹, 90% and a minimum one in the pine (1389 mm y¹, 81% plantations, respectively. Stemflow was very low in the three forest types (1-3 mm y¹, 0.1-0.2%. The maximum amount of water intercepted by forest crowns was found in the pine plantation (329 mm y¹, which accounted for 19% out of the total rainfall. In opposition to the patterns found for throughfall and stemflow, soil hydric flows did show significant differences among forest types (P<0.05. In the oak forest water infiltration inversely decreased with soil depth; this forest type showed the lowest water losses by deep drainage (2 mm y¹. Finally, throughfall and stemflow were significantly correlated with the amount and intensity of rainfall. In conclusion, oak forests showed the highest rainfall regulation capacity, followed by the pine plantation. In contrast, the cypress plantation had a very low rainfall regulation potential once that this forest type was characterized by high and fast water losses by deep drainage.

  15. Recuperación de la biomasa mediante la sucesión secundaria, Cordillera Central de los Andes, Colombia

    Directory of Open Access Journals (Sweden)

    Jorge Ignacio del Valle

    2011-09-01

    Full Text Available En bosques secundarios premontanos tropicales es escasa la información sobre el tiempo requerido para recuperar la biomasa aérea y subterránea de los primarios. Por lo tanto, establecimos 33 parcelas de 0.1ha entre 550 y 1 700m en bosques secundarios que cubrían estadios serales de 3 a 36 años y estimamos la biomasa de las plantas y de las raíces gruesas con ecuaciones locales. Así como la biomasa de las pasturas y barbechos por cosecha de 54 y 18 parcelas, respectivamente. También se calculó la edad de las parcelas con informantes locales, sensores remotos, C14 y anillos de crecimiento. En cada parcela medimos la biomasa aérea viva por hectárea (Bav y la de las raíces gruesas por hectárea (Brg. Modelamos la Bav y Brg en función de la edad mediante la ecuación de von Bertalanfy con asíntotas de 247t/ha (Bav y 66t/ha (Brg resultantes de la medición de 33 parcelas de 0.1ha en los bosques primarios. Con la razón Brg/Bav=f(t estimamos 87 años para que los bosques secundarios recuperen la Bav existente en los primarios y 217 años para recuperar la Brg. La tasa máxima de crecimiento instantáneo de la Bav fue 6.95t/ha/año a los 10 años y la tasa media máxima de crecimiento 6.26t/ha/año a los 17 años. La media ponderada de la tasa de crecimiento absoluto de la Bav alcanzó 4.57t/ha/año y la relativa 10% anual. La razón Brg/Bav inicialmente aumenta muy aceleradamente hasta 4-5 años (25%, luego disminuye hasta 25 años (18% para luego incrementar hasta 26.7

  16. The Jurassic-early Cretaceous arc of the Chilean Coastal Cordillera near Taltal : an assemblage of crustal slivers

    OpenAIRE

    Kurth, D; E. Scheuber; Reutter, K.J.

    1996-01-01

    Au sud de Taltal, la Cordillère de la côte est séparée en deux blocs par le système de faille d'Atacama : à l'ouest, le bloc Cifuncho est composé de trois sous-blocs, limités par des failles, et constitués respectivement de sédiments paléozoïques, de sédiments triasiques à jurassiques, et de volcanites d'arc d'âge jurassique; à l'est, le bloc Pingo est constitué de roches paléozoïques surmontées par des volcanites du Crétacé inférieur. Cet assemblage de blocs est attribué à la subduction obli...

  17. Monogenetic volcanism in the Cordillera Central of Colombia: unknown volcanic fields associated with the northernmost Andes' volcanic chain related subduction

    Science.gov (United States)

    Murcia, Hugo; Borrero, Carlos; Németh, Károly

    2017-04-01

    Monogenetic volcanic fields are commonly related to rifts and/or intraplate tectonic settings. However, although less common, they appear also associated with subduction zones, including both front and back-arc volcanoes. To nourish this uncommon tectonic location, it is shown here that monogenetic volcanic fields, in addition to polygenetic volcanoes, also appear at the northernmost part of the Andes Northern Volcanic Zone (NVZ) (2° S to 4°30´N). These fields are associated with the main axe of the Quaternary active volcanic structures; they are linked to the polygenetic Cerro Bravo - Cerro Machín Volcanic Chain ( 80 km long; CBCMVC) in Colombia, the chain that hosts the iconic Nevado del Ruiz volcano. To the present, three monogenetic volcanic fields, with a typical calc-alkaline signature, have been identified in both sides of this chain: 1) Villamaría - Termales Monogenetic Volcanic Field (VTMVF) located to the northwestern part (>5 km) of the CBCMVC. This field is made up of at least 14 volcanoes aligned with the Villamaría - Termales fault zone. The volcanism has been mainly effusive, represented by lava domes and some lava flows. The volcanoes are andesitic to dacitic in composition. It is inferred that the magmatic source is a magma chamber close to Nevado del Ruiz volcano. Based on stratigraphic relationships, it is assumed that the last eruption occurred 10 wt.%) in the whole CBCMVC. Its source is related to the same magmas that feed the volcanoes in the CBCMVC. Stratigraphic relationships show that the volcanoes are younger than the underlying alluvial and volcaniclastic Ibagué fan (<1 Ma). Overall, it is clear that monogenetic volcanic fields are not atypical in the area, although their relationship with the magmatism feeding the polygenetic arc of the Andes' volcanic chain related subduction, is still unknown.

  18. Geoquímica de las aguas termales con CO2 del SE de las Cordilleras Béticas

    Directory of Open Access Journals (Sweden)

    Martín-Vallejo, M.

    1998-12-01

    Full Text Available The hydrothermalism of the south-east peninsular Alpine zone has been studied under different points of view, such as the geological control, the definition and systematising of its chemistry types and base temperatures, among others, showing always its notable development and its connection with geothermal anomalies of regional character. One of the problems that seems to carry important genetic implications, as well as implications for the utilisation of this water, is the content in carbon dioxide. Twenty-seven physicalchemical parameters in twenty-two water points on a fifty inventory have been studied. High temperatures were recorded for almost all the sampling points, varying between 20 and 41°C. The waters have conductivity between 771 and 5,030 μS cm-1 and increased to the east of the faults systems of Carboneras-Palomares-Guadalentín. In general, the concentration in bicarbonate was high, between 3 and 30 meq/l. The waters present high PC02, being arrived to measure values over 1.17 atmospheres and whose spatial variations are related to the proximity to the faults systems of Carboneras-Palomares-Guadalentín, the one which establishes a threshold between different thickness of the crust. Chemical equilibrium modelling shows that the waters are oversaturated in dolomite, in general saturated in calcite, and undersaturated in gypsum. The high content in CO2, besides the process of dedolomititation caused by the addition of S04~ to the system, helps the formation of travertines in many of the studied points. Isotopic studies show that δ13C values are in the range -S.I to -3.1‰, and reveals that there is an insignificant CO2 supply of deep origin The hydrothermal system of this zone is related to the proposed «C02 Alpine Belt», associated here with a series of grabens with seismic and neotectonic activities.El hidrotermalismo de las zonas alpinas peninsulares ha sido estudiado bajo diferentes puntos de vista, como son el condicionamiento geológico, la definición y sistematización de sus facies químicas y las temperaturas de base, entre otros, mostrando siempre su notable desarrollo y conexión con anomalías geotérmicas de carácter regional. Una de las cuestiones que parece revestir implicaciones genéticas importantes, así como para la utilización de estas aguas, es su contenido en dióxido de carbono. Se han estudiado veintisiete parámetros fisicoquímicos en veintidós puntos de agua sobre un inventario de cincuenta. La mayoría de los puntos acuíferos estudiados tienen una elevada temperatura, comprendida entre 20 y 41°C. Las aguas tienen conductividades que varían entre 771 y 5.030 μS cm-1, y que se incrementan hacia el Este de los sistemas de fallas de Carboneras- Palomares-Guadalentín. En general, las concentraciones de ion bicarbonato son elevadas, comprendidas entre 3 y 30 meq/l. Las aguas tiene PC02 altas, llegándose a medir valores superiores al, 17 atmósferas y cuyas variaciones espaciales están relacionadas con su proximidad a los sistemas de fallas de Carboneras-Palomares-Guadalentín, los cuales establecen un umbral entre diferentes espesores de la corteza. Todas las aguas se encuentran sobresaturadas en dolomita y subsaturadas en yeso, y en general saturadas en calcita. Los altos contenidos en CO2 de las aguas, además de los procesos de dedolomitización originados por la disolución de ion sulfato, contribuyen a la formación de travertinos, presentes en muchos de los puntos acuíferos estudiados. El estudio isotópico realizado permite ver que el δ13C tiene valores comprendidos entre -8,1 y -3,1‰, señalando la existencia de cantidades no despreciables de CO2 de origen profundo. El sistema hidrotermal de esta zona está relacionado con el propuesto «Cinturón de CO2 Perialpino », asociado aquí a una serie de grabens con actividades sísmica y neotectónica.

  19. Flow modelling in a high mountain valley equipped with hydropower plants: Rio Zongo Valley, Cordillera Real, Bolivia

    Science.gov (United States)

    Caballero, Yvan; Chevallier, Pierre; Gallaire, Robert; Pillco, Ramiro

    2004-04-01

    Water management modelling of a hydroelectric system in a tropical high mountain context is presented. The study zone and the hydraulic network are described and the water management strategy analysed. Three different models are combined to describe the complexity of the specific hydrometeorological context: the spatial distribution of the climatic data over the river basin, the surface energy balance influence on the runoff production of a river basin and the surface flow transfer modelling through a hydraulic system. The atmospheric forcing spatial distribution is derived from the available climatic data records. The runoff production on the catchment's slopes is simulated using the land-surface scheme ISBA. The system dynamics tool Vensim® is used to simulate the hydraulic dynamics in the hydropower plants system. A short description of the three modelling methods is given, followed by the description of the coupled model construction. The simulation results of the ISBA land-surface scheme on both a non-glacial an a glacial sub-basin during a 17 month period are presented. After pointing out the necessity of the water management model to simulate the river discharge at the outlet of the basin, the main reservoirs, simulated water level variations are shown.

  20. Hidrogeología del Karst de Pico Frentes (Cordillera Ibérica, España

    Directory of Open Access Journals (Sweden)

    Rosas, P.

    2016-06-01

    Full Text Available The karst system of Pico Frentes has developed within an Upper Cretaceous calcareous series whose well-defined folded geometry determines that its aquifer reserves are held mainly in three hydraulically-connected synclines, with a groundwater capacity of between 5 and 7 hm3 . The recharge to this unconfined peneplain aquifer is autogenous and diffuse. On a large scale, groundwater flow is directed by the base of the synclines, while on a small scale, it flows along groundwater conduits towards the Fuentetoba Spring (210 l/s and source of the River Mazos (50 l/s, following a highly variable flow regime of low inertia, with other smaller discharges emanating during periods of high water. Analysis of hydrographs of these springs indicates a very variable rate system and little power regulating natural, characteristic of a typical karstic aquifer, with great capacity for renewal and low residence time. Using hydrogram simulations of these upwellings using a mathematical rainfall-runoff model, a detailed quantification of the average water balance was made for a twenty-year time series. This water balance consists of 16,86 hm3 rainfall (100%; natural recharge, 8,35 hm3 (49,53%; EVT 8,50 hm3 (50,41%; pumped groundwater abstractions, 0,01hm3 (0,06%; surface runoff, 0 hm3 , groundwater transfers to other aquifer, 0 hm3 .El sistema kárstico de Pico Frentes se ha desarrollado a favor de un conjunto calcáreo del Cretácico Superior cuya geometría plegada muy bien definida ha condicionado que los acuíferos se sitúen principalmente en tres sinclinales hidráulicamente conectados, con una capacidad de reservas subterráneas de entre 5 y 7 hm3 . La recarga en este acuífero libre y en penillanura es autógena y difusa. El flujo subterráneo va dirigido a gran escala por el fondo de los sinclinales y a pequeña escala mediante corrientes subterráneas hacia los manantiales de Fuentetoba (210 l/s y nacimiento del rio Mazos (50 l/s, surgiendo en aguas altas otras descargas menores. El análisis de los hidrogramas de estos manantiales indica un sistema de régimen muy variable y poco poder de regulación natural, característica de un acuífero típicamente kárstico, con gran capacidad de renovación y poco tiempo de residencia. Gracias a la simulación de los hidrogramas de estas surgencias mediante un modelo matemático de precipitación –escorrentía, se ha cuantificado de manera detallada el balance hidráulico medio para una serie de 20 años: aportación pluviométrica 16,86 hm3 (100%, recarga natural 8,35 hm3 (49,53%, EVT 8,50 hm3 (50,41%, bombeo de agua subterránea 0,01hm3 (0,06%, escorrentía superficial 0 hm3 , transferencias subterráneas a otros acuíferos 0 hm3 .

  1. Mississippian through Permian orogenesis in eastern Nevada: Post-Antler, pre-Sonoma tectonics of the western cordillera

    Energy Technology Data Exchange (ETDEWEB)

    Trexler, J.; Cashman, P. (Univ. of Nevada, Reno (United States)); Snyder, W.; Spinoza, C.; Gallegos, D. (Boise State Univ., ID (United States))

    1991-02-01

    Mississippian through Permian strata in eastern Nevada document a series of tectonic events that are either generally unrecognized, or assigned to the Antler or Sonoma orogenies. Some of these events were local and some were regional in scale; none fit either the Antler or Sonoma events as normally defined: Antler orogeny (ends Late Devonian or earliest Mississippian) - emplacement of accretionary wedge on the passive margin; Wendover phase (Early Mississippian) - regional uplift, erosion; Diamond Range phase (Middle Mississippian) - folding, uplift, and erosion; Humboldt orogeny (Pennsylvanian) - uplift, tilting and erosion; Dry Mountain event (Late Pennsylvanian-Early Permian) - uplift, tilting and erosion, and basin segmentation; Sonoma orogeny (Permian-Triassic) - allochthon emplacement. Each event is documented by deformation and erosional truncation of older strata, and by clastic sequences that fill newly formed basins. These tectonic events have mostly escaped notice until now for two reasons: (1) established cratonal stratigraphy, when applied to highly variable craton-edge sequences, tends to obscure important local perturbations, and (2) the assumption of only two Paleozoic orogenies leaves little room for more complexity, and inevitably leads to unresolvable arguments about timing and style. Little-used older terminology (e.g., Wendover phase') is available to describe these events in some cases; refinement or abandonment of existing terminology may be necessary in others. Careful, objective stratigraphic studies will result in a more accurate, and complex regional history.

  2. Thermal and exhumation history of the Costal Cordillera arc of the northern Chile revealed by thermochronological dating

    NARCIS (Netherlands)

    Juez-Larré, J.; Kukowski, N.; Dunai, T.J.; Hartley, A.J.; Andriessen, P.A.M.

    2010-01-01

    The thermal and erosional history of convergent plate boundaries is important for understanding the links between subduction, arc magmatism, genesis of ore deposits, topography and climate of orogenic belts. Unlike the continent-continent collision that formed many of the largest orogenic belts

  3. [Morphoecology guild in beetles (Coleoptera: Passalidae) along an altitudinal gradient in oak forests of the Eastern Cordillera, Colombia].

    Science.gov (United States)

    Moreno-Fonseca, Carlos J; Amat-García, German D

    2016-03-01

    Bess beetles are important components on tropical forest dead wood nutrient cycling, since they act as direct consumers and ease the consumption by another organism (indirect). Studies of bess beetle ecology are scarce and have focused on communities responses to environmental changes on alimentary resources. We characterized the bess beetles guild composition in an elevation gradient, according to their differential use of resources (microhabitat) and morphological traits quantification (geometric and lineal), as a potential tool to improve our understanding on resource use and functional ecology of beetles. Three guilds (underbark, sapwood-heartwood and generalists feeders), five species and 198 familiar groups were recognized; their richness decreased as elevation increased. Changes in linear morphometric measures were influenced by elevation; morphogeometrical measures were not associated with the elevation gradient, only grouping at guild level were observed. Morphological markers analysis (morphometric) provided information to guild delimitation. Body and metatibiae shape contributed with the best information to guild grouping. Quantification of those structural markers proved the relationship between resource repartition, because they are involved in movement on wood galleries and wood consumption, this fact allowed to propose specific functional roles. The identified patterns have contributed on the understanding of functional processes in Passalidae communities and their role in ecosystem function.

  4. Using nanogranite and glassy inclusions to unravel anatexis in the crustal footwall of the Ronda peridotites (Betic Cordillera, S Spain)

    Science.gov (United States)

    Bartoli, Omar; Acosta-Vigil, Antonio; Cesare, Bernardo; Remusat, Laurent; Tajčmanová, Lucie; Wälle, Markus; Heinrich, Christoph; Poli, Stefano; Bodnar, Robert J.

    2015-04-01

    The application of melt inclusion (MI) studies to migmatites and granulites is a recent, small-scale approach to a better understanding of melting in the continental crust [1]. Being trapped by growing peritectic phases at suprasolidus conditions, these MI represent a window into the pre-peak anatectic history of partially melted terranes, and may provide a wealth of microstructural and compositional information on crustal anatexis [2, 3, 4]. The crustal footwall of the Ronda peridotites consists of an inverted metamorphic sequence with migmatites and mylonites at the top. Mylonites represent strongly deformed former diatexites. To shed light on the nature and mechanisms of melting in the migmatites of the Ojén traverse, a detailed microstructural and geochemical study has been conducted on primary 2-10 µm MI hosted in peritectic garnet of i) metatexites at the bottom of the migmatitic sequence and ii) mylonitic former diatexites close to the contact with the mantle rocks. Both metatexites and mylonites have compositions corresponding to peraluminous greywackes. Phase equilibria modeling shows P-T conditions of equilibration of 4.5-5 kbar and 660-700 °C, and of 820-830 °C and 5.5-6.0 kbar for metatexites and mylonites, respectively. Clusters of MI in the metatexites are rounded and preferentially located at the core of small garnet crystals, whereas these clusters may have a sigmoidal to spiral-like shape in garnets of mylonites. MI show a variable degree of crystallization ranging from totally glassy to fully crystallized (i.e., nanogranites), consisting of Qtz+Pl+Kfs+Bt+Ms aggregates (often modal Kfs > Pl in mylonites). Piston cylinder remelting experiments led to the complete rehomogenization of nanogranites in metatexites at the conditions inferred for anatexis: 700 °C and 5 kbar. Rehomogenized nanogranites in metatexites and glassy MI in mylonites are all leucogranitic, although generally plot away from minimum melt compositions. Systematic compositional variations have been observed between MI in metatexites and mylonites. MI in metatexites show higher amounts of H2O and Na2O/K2O ratios, lower FeO content, and higher concentrations of those trace elements controlled by feldspars: Sr, Ba. MI in mylonites have higher concentrations of trace elements controlled by Bt (Cs, Rb and FRTE e.g. Zn, Sc) and accessory minerals (HFSE e.g. Zr, U, Th, and LREE). The compositions of MI in metatexites and mylonites are interpreted to record the composition of the anatectic melts produced from a peraluminous greywacke 1) on, and immediately after crossing, the fluid-saturated solidus of this metasedimentary rock, and 2) during syn-kinematic anatexis via biotite dehydration melting at increasing temperature, respectively. [1] Cesare et al. (2009) Geology, 37, 627-630. [2] Bartoli et al. (2013) Geology, 41, 115-118. [3] Bartoli et al. (2014) EPSL, 395, 281-290. [4] Acosta-Vigil et al. (2010) JPetrol 51, 785-821.

  5. Estructura y riqueza de plantas arborescentes en Un Bosque de Niebla de la Cordillera Central (Tolima, Colombia

    Directory of Open Access Journals (Sweden)

    Campo Kurmen Juan Manuel

    2006-06-01

    Full Text Available Se presenta el estudio de la estructura, la riqueza y la composición florística del componente arborescente de un
    bosque entresacado, en la vereda Dantas, municipio de Ibagué, Tolima, Colombia, con base en el mues-treo de
    los individuos con DAP 2,5 cm en 0,1 ha. El bosque se caracteriza por la escasez de lianas y de hemiepífitas,
    ausencia de familias típicas de bosques de niebla colombianos entre los 2.000 y 2.500 msnm (Araceae, Ericaceae,
    Myrtaceae, Meliaceae y Aquifoliaceae y por un incremento en la riqueza de familias como Sabiaceae y Euphorbiaceae.
    Comparado con otros bosques de niebla de los Andes colombianos y del neotrópico, éste presenta una de las
    más bajas densidades de tallos (237 individuos con DAP ³ 2,5 cm por 0,1 ha y una proporción de árboles grandes
    muy alta (39,7% individuos con DAP 10 cm por 0,1 ha. Aparentemente, los efectos de la extracción selectiva
    de maderas sobre la riqueza, la estructura y la composición, son la disminución de la densidad y la riqueza de lianas, mayor riqueza de Sabiaceae y Euphorbiaceae y mayor densidad de especies secundarias como Hedyosmum goudotianum Slms-Laubach var. goudatianum, Miconia resima Naud. y Palicourea calophlebia Standl.

  6. Reptilia, Squamata, Scincidae, Brachymeles elerae (Taylor, 1917: Rediscovery in Old Balbalan, Cordillera Mountain Range, Luzon Island, Philippines, and natural history

    Directory of Open Access Journals (Sweden)

    Siler, C. D.

    2010-01-01

    Full Text Available Brachymeles elerae (Taylor 1917 is one of 18 recognized lizard species of Brachymeles, and is one of only twospecies known to possess four digits on the fore- and hind limbs. This unique species was originally described on thebasis of two specimens, both lacking locality data, and has long been presumed to occur in the Nueva Vizcaya Provincein the north central region of Luzon Island in the Philippines. In 1920, two additional specimens were collected from theMunicipality of Balbalan of Luzon by E. H. Taylor. All subsequent reviews of the genus have been based on this material. Ireport on the first records of Brachymeles elerae in over ninety years and present the first photograph and new data onmorphology and habitat.

  7. La Zona de Falla del Bajo Segura: cabalgamiento activo “ciego” en la Cordillera Bética oriental

    OpenAIRE

    Alfaro, P.; Bartolomé, Rafael; Borque Arancón, María Jesús; Estévez, A.; García-Mayordomo, J.; García-Tortosa, Francisco Juan; Gil, Alejandro J.; Gràcia, Eulàlia; Lo Iacono, Claudio

    2012-01-01

    The Bajo Segura Fault Zone, located at the NE end of the Eastern Betic Shear Zone, has been the site of some of the most intense seismic activity on the Iberian Peninsula in the historical and instrumental time periods. This structure is an active blind fault that does not show any surface rupture. It is characterised by a set of ENE-WSW trending blind thrust faults that offset the Triassic basement and cause active folding of the Upper Miocene-Quaternary sedimentary cover. The main active st...

  8. A new tectonic discontinuity in the Betic Cordillera deduced from active tectonics and seismicity in the Tabernas Basin

    Science.gov (United States)

    Sanz de Galdeano, Carlos; Shanov, Stefan; Galindo-Zaldívar, Jesús; Radulov, Alexander; Nikolov, Gabriel

    2010-08-01

    In the Tabernas Desert, a Neogene basin situated in SE Spain, major E-W folds coexist with large E-W dextral faults and abundant NNW-SSE faults. These faults affect the Plio-Quaternary sediments. The palaeostress ellipsoids indicate a roughly constant tension ( σ3 axe) in the ENE-WSW direction, coexisting with a changeable direction of the main compression (σ 1 axe) from the vertical to the NW-SE direction. The numerous NNW-SSE faults in southern areas, directly to the east of the city of Almería, tend to propagate northwards, forming a tectonic discontinuity of the Betic Internal Zone. The 2002 seismic swarm of the Gergal earthquake occurred in this NNW-SSE fault zone. In this setting, the E-W fractures act as transfer faults.

  9. Arquitectura precerámica en la cordillera de los Andes, Piruru frene a la diversidad de los datos

    Directory of Open Access Journals (Sweden)

    Elisabeth Bonnier

    1988-12-01

    Full Text Available Los datos sobre la arquitectura precerámica en la cordilleraandina provienen de cinco sitios: La Galgada, Piruru, Huaricoto, Shillacotoy Kotosh. Contexto arqueológico y rasgos arquitectónicos específicos permitenidentificar la función ceremonial de esta arquitectura. La descripciónde las construcciones religiosas pone en evidencia un conjunto pertinente decaracteres comunes. El espacio ceremonial, construido y sin construir, se articulaalrededor del doble elemento arquitectónico fundamental, el fogón yel piso. Para analizar el piso a dos niveles, dos neologismos, pericausto y epicaustohan sido creados. El análisis arquitectónico muestra que el piso es elespacio sagrado por excelencia. Los fechados 14C de los sitios estudiadosdestacan la larga duración del Precerámico Final con arquitectura. A la luz delos últimos trabajos en Piruru y de los cambios arquitectónicos perceptiblesen este sitio, la hipótesis, formulada a principios de este decenio, sobre ·taexistencia de una tradición religiosa única propia de los Andes Centrales, seestá reconsiderando.

  10. Regional Permafrost Probability Modelling in the northwestern Cordillera, 59°N - 61°N, Canada

    Science.gov (United States)

    Bonnaventure, P. P.; Lewkowicz, A. G.

    2010-12-01

    High resolution (30 x 30 m) permafrost probability models were created for eight mountainous areas in the Yukon and northernmost British Columbia. Empirical-statistical modelling based on the Basal Temperature of Snow (BTS) method was used to develop spatial relationships. Model inputs include equivalent elevation (a variable that incorporates non-uniform temperature change with elevation), potential incoming solar radiation and slope. Probability relationships between predicted BTS and permafrost presence were developed for each area using late-summer physical observations in pits, or by using year-round ground temperature measurements. A high-resolution spatial model for the region has now been generated based on seven of the area models. Each was applied to the entire region, and their predictions were then blended based on a distance decay function from the model source area. The regional model is challenging to validate independently because there are few boreholes in the region. However, a comparison of results to a recently established inventory of rock glaciers for the Yukon suggests its validity because predicted permafrost probabilities were 0.8 or greater for almost 90% of these landforms. Furthermore, the regional model results have a similar spatial pattern to those modelled independently in the eighth area, although predicted probabilities using the regional model are generally higher. The regional model predicts that permafrost underlies about half of the non-glaciated terrain in the region, with probabilities increasing regionally from south to north and from east to west. Elevation is significant, but not always linked in a straightforward fashion because of weak or inverted trends in permafrost probability below treeline. Above treeline, however, permafrost probabilities increase and approach 1.0 in very high elevation areas throughout the study region. The regional model shows many similarities to previous Canadian permafrost maps (Heginbottom and Radburn, 1992; Heginbottom et al., 1995) but is several orders of magnitude more detailed. It also exhibits some significant differences, including the presence of an area of valley-floor continuous permafrost around Beaver Creek near the Alaskan border in the west, as well as higher probabilities of permafrost in the central parts of the region near the boundaries of the sporadic and extensive discontinuous zones. In addition, parts of the northernmost portion of the region would be classified as sporadic discontinuous permafrost because of inversions in the terrestrial surface lapse rate which cause permafrost probabilities to decrease with elevation through the forest. These model predictions are expected to of direct use for infrastructure planning and northern development and can serve as a benchmark for future studies of permafrost distribution in the Yukon. References Heginbottom JR, Dubreuil MA and Haker PT. 1995. Canada Permafrost. (1:7,500,000 scale). In The National Atlas of Canada, 5th Edition, sheet MCR 4177. Ottawa: National Resources Canada. Heginbottom, J.A. and Radburn, L.K. 1992. Permafrost and ground ice conditions of northwestern Canada; Geological Survey of Canada, Map 1691A, scale 1:1,000,000. Digitized by S. Smith, Geological Survey of Canada.

  11. Explotación de recursos en la cordillera Huayhuash: la minería y el turismo

    OpenAIRE

    Robles Mendoza, Román; Departamento Académico de Antropología, Facultad de Ciencias Sociales, Universidad Nacional Mayor de San Marcos. Lima - Perú.

    2014-01-01

    The national reserve of the Huayhuash mountain range, located in the borders of the departments of Ancash, Lima and Huánuco, has become in the last years a center coveted for the exploitation of natural resources. Landscaping kindness of high snow-covered mountains, lagoons, plains and defiles have turned it one of the tourist routes of high value in the country and the varied wealth of mineral reserves of good law in the subsoil of this mountain range has caused the foreign investment for it...

  12. [Structure and floristic composition of three oak forests in the northern region of the Central Cordillera in Colombia].

    Science.gov (United States)

    León, Juan D; Vélez, Gladys; Yepes, Adriana P

    2009-12-01

    Andean ecosystems harbor a high floristic diversity, which is being threatened by human disturbances such us deforestation and by the expansion of the agricultural frontier. One of these ecosystems are the Andean oak forests dominated by Quercus humboldtii, a threatened species in Colombia. We assessed the floristic composition and structure of three Andean oak forests located in three localities (San Andrés de Cuerquia, Belmira and Guarne) of Antioquia. The main goal was to determine whether these forests showed similarities in their structure and floristic composition. In each site, a permanent plot of 5000 m2 (0.5 ha) was established. All trees with D > or = 10 cm were sampled and identified to species. The Importance Value Index (IVI) was calculated as the sum of relative density (DeR), dominance (DoR) and frequency (FR) of a species. Trees with 5 trees with D > or = 10 cm in the three forests, the number of species ranged from 18 to 54, whilst the number of individuals ranged from 326 to 680. The Guarne oak forest showed the highest species richness. In all sites, Q. humboldtii (Fagaceae) was the most important species in relation to the IVI, while Clusia sp. (Clusiaceae) and Myrsine coriaceae (Myrsinaceae) were the most important species in San Andrés de Cuerquia, Clethra fagifolia (Clethraceae) was important only in Belmira and Myrcia popayanensis (Myrtaceae) was important in Guarne. The families with the highest number of species were Fabaceae, Melastomataceae and Rubiaceae. Floristic similarity among places was low. The size distribution of trees had an inverse J-shape curve for all sites with changes in the abundance for size class. The three oak forests differed in their structure and floristic composition probably because of different disturbance degrees.

  13. Las mineralizaciones filonianas de fluorita (galena del Calar de San José (sierra de Baza, cordilleras Béticas

    Directory of Open Access Journals (Sweden)

    Torres-Ruiz, J.

    1984-08-01

    Full Text Available The F-(Pb, Zn, Ba district of Sierra de Baza are a (Southeastern Spain is mainly constituted by fluorite-(galene stratiform and stratabound mineralizations which are included in Carbonate levels of Ladinian-Carnian age. These levels also contain vein mineralizations but only in certain zones as de Calar de San José and the Calar de Santa Bárbara. This paper deals with the main structural and mineralogical characteristics of the vein mineralizations and their relations with the geological context evolution. Special attention is given to the tectonic and the spatial association with the stratiform and stratabound, mineralizations of sedimentary/diagenetic character. Two types of vein mineralizations may be distinguished : one type is represented by small "in situ" remobilizations, from the stratiform and stratabound mineralizat ioos, which have been formed during the final stages of alpine deformations; the other one has been formed before Alpina Orogeny and probably in direct relation with an intratriassic tectonic phase.

    El distrito de F-(Pb, Zn, Ba de la Sierra de Baza (al SE de España está constituido fundamentalmente por mineralizaciones estratiformes y estratoligadas de fluorita-(galena, enclavadas en niveles carbonatados del Ladiniense Superior-Carniense. En estos mismos niveles, en algunos sectores como los del Calar de San José y Calar de Santa Bárbara, que constituyen el área de mayor importancia de este distrito minero, dichas mineralizaciones coexisten con otras de tipo filoniano. La presente nota trata esencialmente de las principales características estructurales y mineralógicas de las mineralizaciones filonianas y de sus relaciones con la evolución del contexto geológico, muy especialmente en lo que se refiere a la tectónica y a su asociación espacial con las mineralizaciones estratiformes y estratoligadas de carácter sedimentario/diagenético. Se han diferenciado dos tipos de mineralizaciones filonianas: unas, representadas por removilizaciones "in situ", a pequeña escala, de las de tipo estratiforme y estratoligado, que han ocurrido en las últimas etapas de deformación alpina; y otras, formadas con anterioridad a la orogenia alpina y directamente relacionadas con una tectónica intratriásica de carácter aparentemente distensivo.

  14. Weathering and solute transport to the Salar de Atacama, northern Chile

    Science.gov (United States)

    Hynek, S. A.; Munk, L. A.; Boutt, D. F.

    2013-12-01

    , and 4) the least radiogenic 87/86 ratios which are found along the western margin of the basin and may have their source in the Cordillera Domeyko. The Sr isotope composition of brine in Salar de Atacama is dominated by sources from the Neogene to modern volcanic arc along its eastern margin. Lithium isotope ratios of freshwater influx are depleted in lithium-7 compared to the brines, and brackish waters are transitional between the two. These data implicate precipitation and/or dissolution of secondary minerals, as the majority of these processes take place where freshwater interacts with evaporite minerals, brackish water, and brines. The lithium isotopic composition of water draining the volcanic arc suggest a limited role for precipitation of Li-bearing secondary minerals associated with freshwater solute fluxes in surface and shallow groundwater. Near surface solute fluxes are constrained by concentrations of tritium, an anthropogenic radioisotope of hydrogen indicative of groundwater recharge (and residence times) within the last 60 years. This multi-isotope approach demonstrates how isotope geochemistry can identify and constrain important processes, pathways and timescales in the Critical Zone.

  15. Late Triassic (Rhaetian) conodonts and ichthyoliths from Chile

    OpenAIRE

    Sansom, Ivan J

    2000-01-01

    The Late Triassic of the back arc Domeyko Basin, Chile is characterized by the onset of marine sedimentation that persisted throughout the rest of the Mesozoic. Carbonate bulk samples from the Punta del Viento Limestone Formation have yielded a numerically small, but apparently widespread, conodont fauna including Epigondolella mosheri, Epigondolella englandi and Neogondolella steinbergensis. These specimens indicate a Rhaetian (Epigondolella mosheri conodont Biozone roughly equivalent to the...

  16. ESO Delegation to Visit Chile: the Chile-Eso Treaty and Paranal

    Science.gov (United States)

    1994-05-01

    . The top of the mountain has been levelled to make place for the extensive VLT installations. ESO has constructed a road from the main road in the area (the ``Old Panamericana'') to the summit. It passes by the ESO base camp (in the foreground, left of the road). The constructors' camp is located on the other side of the road. This photo (ESO PR Photo 08/94-1) accompanies ESO Press Release 08/94 of 6 May 1994 and may be reproduced, if credit is given to the European Southern Observatory. ESO PR PHOTO 08/94-2: CERRO PARANAL This aerial photo of the Paranal mountain, the designated site for the ESO Very Large Telescope (VLT), was obtained on 22 March 1994. Paranal is located in the driest part of the Chilean Atacama desert, approx. 130 km south of the city of Antofagasta, and about 12 km from the Pacific Ocean. The altitude is 2650 metres. In this view towards the East, the high mountains of the Andean Cordillera are in the background. The top of the mountain has been levelled to make place for the extensive VLT installations. The four excavations for the buildings that will house the four 8.2 metre VLT unit telescopes are clearly seen. There are some dust clouds from the construction activity at the site. There are several other peaks in this area which may possibly be used for astronomical installations. The one to the left on which some site testing equipment can be seen, is known as the ``NTT Peak''. This photo (ESO PR Photo 08/94-2) accompanies ESO Press Release 08/94 of 6 May 1994 and may be reproduced, if credit is given to the European Southern Observatory. ESO PR PHOTO 08/94-3: CERRO PARANAL This aerial photo of the Paranal mountain, the designated site for the ESO Very Large Telescope (VLT), was obtained on 22 March 1994. Paranal is located in the driest part of the Chilean Atacama desert, approx. 130 km south of the city of Antofagasta, and about 12 km from the Pacific Ocean. The altitude is 2650 metres. The top of the mountain has been levelled to make place

  17. ESTADO DE LA POBLACIÓN DE MONOS AULLADORES ROJOS EN EL CAÑÓN DEL BARBAS, FRAGMENTO MONTANO, CORDILLERA CENTRAL, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Gomez-Posada Carolina

    2010-04-01

    Full Text Available

    Los bosques de montaña en Colombia han sufrido fuerte degradación por causas antrópicas; en la actualidad la mayoría son remanentes aislados e inmersos en hábitats antropogénicos. Los aulladores rojos han persistido en estas condiciones pero poco se conoce sobre su biología y respuesta a la alteración de su ambiente. Evaluamos la densidad poblacional y estatus de esta especie en la cuenca del río Barbas (Quindío y Risaralda, fragmento de bosque montano bajo (790 ha. Estimamos la densidad empleando censos por transectos lineales repetidos. Adicionalmente seguimos tropas de aulladores y evaluamos variables de vegetación teniendo en cuenta los requerimientos de la especie. Estimamos una densidad de 11.7±6 grupos y 132.1±68 individuos por km2, para un tamaño poblacional de 1044 aulladores. El tamaño promedio por tropa fue 11, con elevado número de individuos en capacidad de reproducirse y pocos individuos inmaduros (lo cual indica posibles alteraciones sociales. En general el bosque ofrece buena disponibilidad de recursos estructurales y alimenticios para los aulladores. Esta población no se encuentra amenazada en la actualidad por actividades antrópicas, el bosque se encuentra en buen estado con pequeñas zonas en recuperación, la frontera agrícola se encuentra estable y no hubo evidencias de cacería. El fragmento ha sido recientemente protegido bajo la figura de Parque Regional Natural y se adelantan corredores de conexión con otros remanentes. Sin embargo, esta población de aulladores se encuentra aislada de otras poblaciones y por tanto es urgente desarrollar medidas de manejo del paisaje para atenuar los efectos del aislamiento.

  18. Stingless Bees (Hymenoptera: Apidae: Meliponini in Oriental Mountains Cementeries from Colombia Abejas sin aguijón (Hymenoptera: Apidae: Meliponini en cementerios de la Cordillera oriental de Colombia

    Directory of Open Access Journals (Sweden)

    Danny Vélez E.

    2006-06-01

    Full Text Available In 11 cemeteries of Cundinamarca and Meta (Colombia departments we found 203 nests of stingless bees pertaining to 15 species. The majority of the found nests (61% belong to genus Nannotrigona Cokerell, 1922. Nannotrigona mellaria was the specie with the greater nests number and higher population; Trigona (Tetragonisca angustula was found in all cemeteries, but in a smaller percentage that N. mellaria (29% of the total. In the Tena (Cundinamarca cemetery was found the nest highest density (118 nest/ha, with a tombs occupation percentage of 13.9%. We discussed the importance of cemeteries as an alternative for wild bees nesting sites conservation in urban areas.Se encontraron 203 nidos de abejas sin aguijón pertenecientes a 15 especies en 11 cementerios de los departamentos de Cundinamarca y Meta (Colombia. El 61% de los nidos encontrados pertenecen a abejas del género Nannotrigona Cokerell, 1922. La especie con el mayor número de nidos y mayor representatividad en los cementerios estudiados fue Nannotrigona mellaria; Trigona (Tetragonisca angustula se encontró en todos los cementerios estudiados pero, en un porcentaje menor que N. mellaria (29% del total. La densidad máxima encontrada fue de 118 nidos/ha, con un porcentaje de ocupación de las tumbas de 13,9% en el cementerio de Tena (Cundinamarca. Se discute sobre la importancia de los cementerios como alternativa para conservación de los sitios de nidificación para abejas silvestres en áreas urbanas.

  19. On the impact of using downscaled reanalysis data instead of direct measurements for modeling the mass balance of a tropical glacier (Cordillera Blanca, Peru)

    Science.gov (United States)

    Galos, Stephan; Hofer, Marlis; Marzeion, Ben; Mölg, Thomas; Großhauser, Martin

    2013-04-01

    Due to their setting, tropical glaciers are sensitive indicators of mid-tropospheric meteorological variability and climate change. Furthermore these glaciers are of particular interest because they respond faster to climatic changes than glaciers located in mid- or high-latitudes. As long-term direct meteorological measurements in such remote environments are scarce, reanalysis data (e.g. ERA-Interim) provide a highly valuable source of information. Reanalysis datasets (i) enable a temporal extension of data records gained by direct measurements and (ii) provide information from regions where direct measurements are not available. In order to properly derive the physical exchange processes between glaciers and atmosphere from reanalysis data, downscaling procedures are required. In the present study we investigate if downscaled atmospheric variables (air temperature and relative humidity) from a reanalysis dataset can be used as input for a physically based, high resolution energy and mass balance model. We apply a well validated empirical-statistical downscaling model, fed with ERA-Interim data, to an automated weather station (AWS) on the surface of Glaciar Artesonraju (8.96° S | 77.63° W). The downscaled data is then used to replace measured air temperature and relative humidity in the input for the energy and mass balance model, which was calibrated using ablation data from stakes and a sonic ranger. In order to test the sensitivity of the modeled mass balance to the downscaled data, the results are compared to a reference model run driven solely with AWS data as model input. We finally discuss the results and present future perspectives for further developing this method.

  20. El adoratorio del cerro El Potro: Arqueología de alta montaña en la cordillera de Copiapó, norte de Chile

    OpenAIRE

    Moyano,Ricardo

    2009-01-01

    Se exponen los resultados del reconocimiento arqueológico de las nacientes del río Los Helados y del cerro El Potro, en el valle de Copiapó. El objetivo principal fue constatar evidencias descritas para la zona que dieran cuenta de una huaca prehispánica, como también definir la orientación orográfica de la arquitectura del centro metalúrgico Viña del Cerro. Los resultados sugieren que existieron prácticas culturales vinculadas con la tradición andina de adorar a las montañas, que incluyeron ...

  1. Hidrogeoquímica de los manantiales sulfhídricos y ferruginosos de las facies Purbeck-Weald del noroeste de la Cordillera Iberica (provincia de Soria

    Directory of Open Access Journals (Sweden)

    Sanz Pérez, E.

    1994-08-01

    Full Text Available The goal of this article is to study the chemical composition of the sulfide-bearingand iron-rich springs in Soria. These springs are mainly located on sedimentary rocks of the Purbeck-Weald facies and most precisely in the Oncala group materials. Sulfide-bearing spring water belongs to calcium sulfate facies. It pH is basic or neutral. This kind of springs is mainly in the eastern area of Oncala group. Sulfate reduction with presence of organic matter seems to be the most common ORIGIN of the H2S. lronrich springs are more often located in the westside of Oncala group. Water of these springs has calcium bicarbonate character, very low salinity and acid pH. These differences on major ion chemical composition likely show the influence of the lithologic and mineralogic changes in the Oncala group. It presents low soluble terrigenous sediments in the western area whereas eastward there is a facies lateral change with the appearance of carbonates and sulfates. On the other hand, none of the iron-rich springs contains H2S and coversely Fe is never detected in the sulfide-bearing springs, although sometimes they appear together. This fact is in accordance with the plot of the two water types have in the pH/Eh diagrams.El objetivo de este trabajo consiste en el estudio de la composición química de las aguas de los manantiales sulfhídricos y ferruginosos existentes en la provincia de Soria. Este tipo de surgencias se encuentran principalmente en los materiales de las facies Purbeck-Weald, y más concretamente en los afloramientos del grupo Oncala. Los manantiales sulfhídricos son de facies sulfatada cá1cica, pH neutro o básico, y se concentran en el sector oriental del grupo Oncala; en la mayoría de los casos, el origen del H2S parece deberse a procesos de reducción de sulfatos en presencia de materia orgánica. Los manantiales ferruginosos tienden a ser más frecuentes en el sector oeste del grupo Oncala, donde presentan un carácter bicarbonatado cálcico, muy baja salinidad ypH ácido. Estas diferencias en la facies hidroquímica se corresponden con un cambio lateral de facies del grupo Oncala: éste presenta sedimentos terrígenos poco solubles en el sector occidental, y rocas ca1cáreas y evaporitas en el sector occidental.Por otro lado, ningún manantial ferruginoso tiene H2S y a la inversa, en ningúnmanantial sulfbídrico se detecta Fe, aunque en ocasiones ambos tipos de surgencias esténpróximas y sobre el mismo tipo de litología. Este hecho es coherente con la posición de estos tipos de aguas dentro de los diagramas de pH/Eh.

  2. Late Palaeozoic to Triassic formations unconformably deposited over the Ronda peridotites (Betic Cordilleras: Evidence for their Variscan time of crustal emplacement

    Directory of Open Access Journals (Sweden)

    Sanz de Galdeano, C.

    2016-06-01

    Full Text Available The age of the emplacement of the Ronda Peridotites has been widely debated during recent decades, and ages ranging from the Palaeozoic to the early Miocene have been proposed, although most of the current interpretations suggest an Oligocene-Miocene age. In this article, we describe two meta-sedimentary formations (the lower one formed by detrital sediments and the upper one by marbles that were unconformably deposited over the Ronda peridotites and now record low-grade metamorphism. The detrital formation contains layers of acidic rocks with an age of 269±9 Ma and the overlying marbles are assumed to be Triassic. The existence of these unconformable formations over the peridotites is crucial for the dating of the exhumation of the latter. The presence of peridotite clasts in the detrital formation indicates that peridotites were exposed during the Permian and other data suggest that peridotites were exhumed during the late Carboniferous. During the Alpine cycle, the peridotites operated as an element situated at the bottom of the tectonically higher Alpujarride/Sebtide unit (the Jubrique unit and forming part of it, then being incorporated to the Alpine thrusts of this unit.La edad del emplazamiento de las peridotitas de Ronda ha sido discutida ampliamente en las últimas décadas, con hipótesis que van desde el Paleozoico al Mioceno inferior, aunque la mayoría de las interpretaciones actuales sugiere una edad oligo-miocena. En este artículo, describimos la existencia de dos formaciones meta-sedimentarias (la inferior formada originalmente por sedimentos detríticos y la superior por carbonatos que se depositaron en discordancia sobre las peridotitas de Ronda y ahora registran un grado bajo de metamorfismo. La formación detrítica contiene capas de rocas ácidas con una edad de 269±9 Ma y los mármoles situados encima se atribuyen al Trías. La existencia de esas dos formaciones es crucial para la datación de la exhumación de las peridotitas. La presencia de clastos de peridotitas en la formación detrítica indica que aquellas estuvieron expuestas durante el Pérmico, otros datos sugieren que las peridotitas fueron exhumadas durante el Carbonífero superior. Durante el ciclo alpino, las peridotitas actuaron como un elemento ya antes situado en la base de la unidad Alpujárride/ Sébtide superior (unidad de Jubrique, formando parte de ésta.

  3. DESCRIPCION GEOGRAFICA E IDENTIDAD TERRITORIAL: REPRESENTACIONES HIAPANAS DE LA CORDILLERA DE LOS ANDES DEL REINO DE CHILE EN EL SIGLO XVI

    OpenAIRE

    VEGA PALMA, ALEJANDRA; VEGA PALMA, ALEJANDRA

    2005-01-01

    A imagen del argumento de Edmundo O'Gorman ampliamente aceptado por la historiografía, que sostiene que el continente americano no estaba allí para la riera aprehensión de los conquistadores, sino que su identidad se fue elaborando históricamente mediante 329p.

  4. Provencance of the late Proterozoic to early Cambrian metaclastic sediments ot the Sierra de San Luis (Eastern Sierras Pampeanas) and Cordillera Oriental, Argentina

    DEFF Research Database (Denmark)

    Drobe, M.; López de Luchi, M.; Steenken, A.

    2009-01-01

    Provenance studies have been performed utilising major and trace elements, Nd systematics, whole rock Pb-Pb isotopes and zircon U/Pb SHRIMP data on metasedimentary rocks of the Sierra de San Luis (Nogolí Metamorphic Complex, Pringles Metamorphic Complex, Conlara Metamorphic Complex and San Luis F...

  5. Equilibrium Line Altitude Fluctuation on the South West Slope of Nevado Coropuna Since The Last Glacial Maximum (Cordillera Ampato, Perú

    Directory of Open Access Journals (Sweden)

    Campos, Néstor

    2015-12-01

    Full Text Available The main aim of this research was to reconstruct the LLGM (local last glacial maximum, 1955 and 2007 glacial phases on the South West slope of Nevado Coropuna to obtain valuable information on the changes that have occurred and analyze the glacier evolution. For this purpose the ELA (Equilibrium Line Altitude indicator has been used as a reference, with the AABR (Area x Altitude Balance Ratio method, based on the principle of weighting the mass balance according to the distance above or below the ELA of that area. An ELA of 4762 m was obtained for the LLGM, 5779 m for 1955 and 5850 m for 2007, implying a vertical shift of 1088 m from the LLGM to 2007 and of 71 m from 1955 to 2007. The total glaciated surface was reduced by 21.5% between 1955 and 2007 and the temperature shift from LLGM to 2007 was 9.13 ºC (0.0091ºC/m. The ice of glaciers makes them valuable for climate research, this method offers quantitative information and the analysis of this data may contribute to research into climate change and climatic trends for future predictions.El principal objetivo de esta investigación es reconstruir las fases glaciares del Último Máximo Glaciar Local (LLGM, 1955 y 2007 en la vertiente Suroeste del Nevado Coropuna para obtener información sobre los cambios ocurridos y analizar la evolución glaciar. Para este propósito el indicador de la altitud de la línea de equilibrio glaciar (ELA ha sido utilizado como referencia, calculado con el método AABR (Area x Altitude Balance Ratio, basado en el principio de ponderación del balance de masa en función de la distancia por encima o debajo de la ELA de esa área. Se obtuvo una ELA de 4762 m para el LLGM, 5779 m para 1955 y 5850 m para 2007, lo que implica una variación de 1088 m desde el LLGM hasta el 2007 y 71 m desde 1955 hasta 2007. La superficie total glaciada se redujo un 21,5% entre 1955 y 2007 y la variación de temperatura desde el LLGM hasta 2007 fue de 9,13 ºC (0,0091ºC/m. El hielo de los glaciares los convierte en un elemento importante para estudios climáticos, este método ofrece información cuantitativa y el análisis de los datos puede contribuir a investigaciones sobre el cambio climático y tendencias climáticas para predicciones futuras.

  6. Estudios ecológicos en la cordillera oriental colombiana iii. - la vegetación de la cuenca del lago de tota (boyacá)

    OpenAIRE

    Rangel Ch., Orlando; Aguirre C., Jaime

    2012-01-01

    En la geomorfología y en el clima de la cuenca del lago de Tota, se diferencian dos regiones: nor-oriental y nor-occidental. En la primera las condiciones ecológicas son favorables y permiten una mayor cobertura y diversidad de la vegetación; la región nor-occidental por el contrario, esta sujeta a condiciones ecológicas drásticas, muestra una vegetación muy pobre y en general el paisaje es de tipo "árido".  La preliminar caracterización de los suelos, indica que en su mayoría, estos son bast...

  7. Diversidad floristica y estructura de remanentes de bosque andino en la zona de amortiguacion del parque nacional Natural los nevados, cordillera central Colombiana

    National Research Council Canada - National Science Library

    Alvear, Marcela; Betancur, Julio; Franco-Rosselli, Pilar

    2010-01-01

    Se caracterizo la diversidad, la composicion floristica y la estructura de los bosques de la Reserva Torre Cuatro, la cual hace parte de la zona amortiguadora del Parque Nacional Natural Los Nevados...

  8. Estructura y estratigrafía de la sierra de los Guajares y sectores próximos (Conjunto Alpujarride, Cordilleras Béticas

    Directory of Open Access Journals (Sweden)

    Sanz de Galdeano, C.

    1990-04-01

    Full Text Available The Guajares and Chaparral-Guindalera Sierras are mainly formed by carbonatic materials, of Middle and Upper Triassic (and perhaps of the Lower Liassic age, belonging to the Almijara Unit (Alpujarride Complex. Their structure is mainly formed by thrust-slides (and younger faults affecting them. The Almijara Unit is overthrusted by the Guajares Unit (including in this Unit the Salobreña Sub-unit. In its thrusting, the Guajares Unit, is progressively situated over more modern materials of the Almijara Unit, inducing in it other lesser trust-slides. Boths units, Almijara and Guajares, overthrusted the Escalate Unit (with an approximate NNW to NW direction and sense causing important tectonic thinning.Las sierras de Los Guájares y Chaparral-Guindalera están formadas fundamentalmente por materiales carbonáticos del Trías medio y superior (que incluso pueden alcanzar al Lías inferior de la unidad de Almijara (Conjunto Alpujárride. Los rasgos fundamentales de su estructura son las escamas (y las fallas que las cortan. La unidad de Almijara se encuentra cabalgada por la unidad de Los Guájares (en la que se engloba la de Salobreña. En su cabalgamiento, la unidad de Los Guájares, se sitúa progresivamente sobre términos más altos de la unidad de Almijara, a la que induce otras escamaciones. Ambas unidades cabalgan a su vez sobre la de Escalate (con una dirección y sentido aproximados NNO a NO, produciéndose fuertes laminaciones.

  9. Hidrogeología del acuífero kárstico de Pico Frentes (Cordillera Ibérica)

    OpenAIRE

    Rosas Rodrigo, Pablo

    2016-01-01

    El sistema kárstico de Pico Frentes se ha desarrollado a favor de un conjunto calcáreo del Cretácico Superior cuya geometría plegada muy bien definida ha condicionado que los acuíferos se sitúen principalmente en tres sinclinales hidráulicamente conectados, con una capacidad de reservas subterráneas de entre 5 y 7 hm3. La recarga en este acuífero libre y en penillanura es autógena y difusa. El flujo subterráneo va dirigido a gran escala por el fondo de los sinclinales y a peque...

  10. Del santuario al caserío: acerca de la neolitización en la Cordillera de los Andes Centrales

    Directory of Open Access Journals (Sweden)

    1988-01-01

    Full Text Available Les faits archéologiques mis en évidence sur le site de Piruru ouvrent des perspectives nouvelles sur la sédentarisation et l'apparition du village dans les Andes centrales. Piruru présente, au Précéramique Final (3000/2500 - 1800/1500 av.JC, une longue période de construction à des fins religieuses avant que n'existent, au Formatif Initial et Moyen (1800/1500 - 800/600 av.JC, des structures à usage domestique. Cette antériorité de l'architecture publique et cérémonielle, observable à l'échelle régionale, permet de proposer l'hypothèse qu'au Précéramique Final, les sanctuaires montagnards jouent un rôle catalyseur, non seulement dans la naissance et le développement de l'architecture, mais aussi dans l'organisation spatiale des communautés en cours de sédentarisation. Durant la longue occupation du Précéramique Final, plus de 1000 ans, les premières phases de la séquence de Piruru montrent l'existence de petits temples, qui sont les plus anciens connus actuellement dans les Andes centrales. Ensuite, la phase plus récente du temple P1 permet de relier Piruru aux autres sanctuaires connus, et de définir la tradition Mito, courant religieux qui se manifeste dans les Andes d'Ancash et de Huánuco, durant la deuxième partie du Précéramique Final. Au Formatif Initial, dans le même temps où la céramique est introduite sur le site, Piruru devient un petit habitat groupé, premier exemple connu à ce jour en montagne. Au cours d'un processus long de plus de 700 ans, les transformations dans l'organisation globale de l'habitat indiquent un degré croissant de sédentarité, et montrent le passage d'un hameau utilisé de façon saisonnière à un village habité de façon permanente, la sédentarité paraissant acquise au début du Formatif Moyen. Los hechos arqueológicos puestos en evidencia en el sitio de Piruru ofrecen nuevas perspectivas sobre la sedentarización y la aparición de la aldea en los Andes centrales. Piruru presenta, en el Precerámico Final (3000/2500 - 1800/1500 a.C., un largo período de construcción con fines religiosos antes de que existan, en el Formativo Inicial y Medio (1800/1500 - 800/600 a.C., estructuras de uso doméstico. Esta anterioridad de la arquitectura pública y ceremonial, observable en la escala regional, permite proponer la hipótesis que durante el Precerámico Final, los santuarios de la sierra tienen un rol catalizador, no sólo en lo que concierne al surgimiento y al desarrollo de la arquitectura, sino también en lo referente a la organización espacial de las comunidades en proceso de sedentarización. Durante la larga ocupación del Precerámico Final, más de 1000 años, las primeras fases de la secuencia de Piruru muestran la existencia de templetes que son los más antiguos que se conocen hasta hoy en los Andes Centrales. Luego, la fase más reciente del Templo P1 permite vincular Piruru a los demás santuarios conocidos y definir la tradición Mito, corriente religiosa que se manifiesta durante la segunda parte del Precerámico Final en las sierras de Ancash y Huánuco. En el Formativo Inicial, al mismo tiempo que se introduce la cerámica en el sitio arqueológico, Piruru se transforma en un pequeño hábitat agrupado, primer ejemplo conocido hoy en día en la sierra. En el transcurso de un largo proceso de más de 700 años, las transformaciones en la organización global del asentamiento indican un grado creciente de sedentarismo y muestran la transición desde un caserío utilizado de manera temporal hasta una aldea poblada de modo permanente, pues el sedentarismo parece haber sido adquirido al principio del Formativo Medio. 'From Shrine to Hamlet: About the Neolithic Process in the Central Andes Highlands'. The archaeological evidence found in Piruru opens new perspectives about sedentism and the rise of the village in the Central Andes. Piruru presents, during the Late Preceramic (3000/2500 -1800/1500 BC, a long period of construction for religious purposes prior to the appearance of structures for domestic use in the Early and Middle Formative (1800/1500 -800/600 BC. The earlier beginning of public and ceremonial architecture which is observed on the regional level permits the formulation of the hypothesis that the Late Preceramic shrines in the highlands play a catalyzing role, not only in the appearance and development of architecture but also in the spatial organization of the communities in the process of establishment of sedentary life. During the long occupation of the Late Preceramic period, more than 1000 years, the first phases of the Piruru sequence show the existence of small temples which are, until the present, the earliest known in the Central Andes. The following phase of the temple P1 permits relating Piruru with the other known shrines and defining the presence of the Mito religious tradition in the Andes of Ancash and Huanuco during the second part of the Late Preceramic Period. When the Early Formative Period begins, at the same time that ceramics appear on the site, Piruru becomes a small clustered settlement, the first example known in the highlands to date. A long process of change in habitat settlement pattern occurs during the passage of more than 700 years. This process demonstrates an increasing degree of sedentism and shows the change from hamlet used seasonally to a permanent village, the sedentary life apparently being established in the beginning of the Middle Formative.

  11. Alteraciones por el fuego en la Cordillera de la Costa de Chile mediterráneo. Antecedentes en un parque nacional

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    Quintanilla Pérez, Víctor

    1996-12-01

    Full Text Available The Cerro de la Campana range, in the central part of Chile, is described. The area has several important features, and parts of it have been declared as National Park. Besides the high taxonomic and ecology diversity, both in animals and in plants, it has the southernmost forests of palm trees, as well as many other subtropical residual forests. Many species reach here the extreme south limit. But the ecosystems of the area are endangered and most of them have been decreasing or even vanishing in the past because of the human pressure. The main dangers come from fire and from slash cutting, although many natural communities there seem to be adapted to periodic burns. The consequences of these dangers and some protective measures are discussed.

    Se describe la cadena del Cerro de la Campana, cuyos recursos naturales han determinado la creación en la zona de un Parque Nacional. Los aspectos más interesantes de la zona se relacionan con la existencia en la misma de bosques subtropicales relictos, así como de bosquetes de palmeras en los que la familia palmáceas alcanza su límite extremo meridional. Por otra parte, la variedad ecológica del área es muy elevada, al igual que su riqueza específica, puesto que alberga 7tiuverosas especies de vertebrados, invertebrados y plantas. Muchas especies encuentran aquí su límite meridional absoluto. Sin embargo la zona se encuentra amenazada por la presión humana, especialmente en la forma de incendios forestales y tala masiva, a pesar de que muchas comunidades naturales parecen estar adaptadas a los incendios repetidos. En el trabajo se analizan las consecuencias de estas amenazas y se sugieren medidas encaminadas a la protección del paraje.

  12. Late Palaeozoic to Triassic formations unconformably deposited over the Ronda peridotites (Betic Cordilleras): Evidence for their Variscan time of crustal emplacement

    Energy Technology Data Exchange (ETDEWEB)

    Sanz de Galdeano, C.; Ruiz Cruz, M.D.

    2016-07-01

    The age of the emplacement of the Ronda Peridotites has been widely debated during recent decades, and ages ranging from the Palaeozoic to the early Miocene have been proposed, although most of the current interpretations suggest an Oligocene-Miocene age. In this article, we describe two meta-sedimentary formations (the lower one formed by detrital sediments and the upper one by marbles) that were unconformably deposited over the Ronda peridotites and now record low-grade metamorphism. The detrital formation contains layers of acidic rocks with an age of 269±9 Ma and the overlying marbles are assumed to be Triassic. The existence of these unconformable formations over the peridotites is crucial for the dating of the exhumation of the latter. The presence of peridotite clasts in the detrital formation indicates that peridotites were exposed during the Permian and other data suggest that peridotites were exhumed during the late Carboniferous. During the Alpine cycle, the peridotites operated as an element situated at the bottom of the tectonically higher Alpujarride/Sebtide unit (the Jubrique unit) and forming part of it, then being incorporated to the Alpine thrusts of this unit. (Author)

  13. LA PLANIFICACIÓN EN LOS ESPACIOS NATURALES PROTEGIDOS: APLICACIÓN DE LOS PORN EN LAS CORDILLERAS BÉTICAS ANDALUZAS

    Directory of Open Access Journals (Sweden)

    Enrique Arias Ibáñez

    2007-01-01

    Full Text Available El esquema legal que alberga en España los espacios naturales protegidos conlleva la implicación de la Administración regional en las tareas de planifi cación, ordenación y gestión de los recursos naturales. En Andalucía, al fuerte impulso en su declaración en 1989 no le siguió el mismo interés por aprobar los instrumentos pertinentes, de cuyos retrasos derivaron importantes errores que en los últimos años se están subsanando. En este trabajo se presta especial atención a lo sucedido con la zonificación que los Planes de Ordenación de los Recursos Naturales incorporan como herramienta para la protección y limitación de actividades. Pese a los avances alcanzados, una cuestión clave para la conservación como la regulación de los cambios en los usos del suelo, aún no ha recibido la atención que precisa.

  14. El paleoceno de la alta cadena (subbetico interno, Cordillera Betica implicaciones en la evolución geodinamica del paleomargen sud-iberico

    Directory of Open Access Journals (Sweden)

    Martín-Martín, M.

    2002-08-01

    Full Text Available No formal formations have been defined taking into account the structural deformation and low quality of the Paleocene outcroppings open platform sediments from the High Chain area (Interna1 Subbetic, Málaga Province. Nevertheless, the better series are indicated, and a division in two depositional sequences are proposed: Lower Paleocene Depositional Sequence (SDPI and Upper Paleocene Depositional Sequence (SDPS, the later being sub-divided in two parasequences (P1 and P2 obtained from the clay mineralogy. The sequences have been defined on the basis of unconformity surfaces interpreted as due to tectonic or eustatic processes. It is proposed the geodynamic evolution of this materials belonging to the South-Iberian paleomargen according with stratigraphical, mineralogical and sedimentary analysis data and shows also the main characteristics of source areas during this period.La complejidad estructural de la región de la Alta Cadena (Subbético Interno de la Provincia de Málaga y la baja calidad de los afloramientos no ha permitido definir formalmente formaciones en los materiales paleocenos de plataforma abierta. No obstante, sí se indican los lugares de mejor exposición de las series, proponiendo una división en dos secuencias deposicionales: Secuencia Deposicional del Paleoceno Inferior (SDPI y Secuencia Deposicional del Paleoceno Superior (SDPS que, a su vez, queda dividida en dos parasecuencias (P1 y P2 obtenidas a partir del estudio mineralógico. Se definen estas secuencias a partir del reconocimiento de las superficies de discontinuidad que las delimitan, siendo éstas interpretadas como debidas a procesos tectónicos, en unos casos, o a procesos eustáticos, en otros. Se propone la evolución geodinámica de estos materiales mediante el estudio estratigráfico, mineralógico y análisis sedimentario. De forma complementaria se apuntan las principales características de sus áreas fuente durante este período.

  15. Modelamiento estructural basado en un analisis de deformaciones en el frente del Piedemonte Llanero Cordillera Oriental de Colombia. (Segmento comprendido entre Sabanalarga y Aguazul)

    OpenAIRE

    Piraquive Bermúdez, Alejandro

    2011-01-01

    La evolución temprana de la Cuenca Cretácica Colombiana representa un caso ilustrativo de una cuenca tectónica extensional en un ambiente tectónico de retro-arco. La paleogeografía variada en cuencas de Rift es un factor principal que controla las transiciones faciales de una unidad sintectónica. Una particularidad de este marco estructural se refiere a la reactivación Neógena de las fallas inicialmente normales como fallas inversas y a la inversión de la cuenca que fue particular...

  16. Dinámica de elementos en epífitos de un bosque altoandino de la cordillera oriental de colombia

    OpenAIRE

    Caballero Rueda, Luis Martín; Rodríguez, Nelly; Martín, Carlos

    2010-01-01

    The reserves and transfer of bioelements were studied during two years in the epiphytic bryophytes and the bromeliad Tillandsia compacta in a high Andean forest in Guisquiza, La Calera, Cundinamarca in the Eastern Andes of Colombia. Epiphyte biomass in this forest is 3766 kg/ha, ofwhich bryophytes contribute 55% and T.compacta, 9.3%. In relation to their biomass, these epihyttes store high quantities of water and nutrients and intercept materials washed from foliage, making them important to ...

  17. The effect of pre-Hispanic agriculture practices on soils in the Western Cordillera of the Peruvian Andes (region Laramate, 14.5°S)

    Science.gov (United States)

    Leceta, Fernando; Mächtle, Bertil; Schukraft, Gerd; Eitel, Bernhard

    2013-04-01

    An integrated geoarchaeological study focuses on a group of three archaeological sites. This study comprises soils on pre-Columbian artificial terraces against their nondisturbed pedological context. Six terraces and three soils lacking of archaeological evidence and actual use, are examined to identify morphological and geochemical features generated by the sustained agrarian use. Aim is to understand the land-use and pedological history of the Laramate region, as an agricultural center in pre-Columbian times. Preliminary results show recurrent sequences within the terraces, characterized by two edaphic cycles; a poorly developed Ap modern topsoil is underlaid by one well-preserved 2Ah paleosol. Analytical data shows prehispanic terraces as a sustained agricultural system. Marked by its use and position, higher availability of nutrients and deeper soils, are found at agricultural terraces, located over a debris cone. Significant charcoal fragments for radiocarbon dating at Ayllapampa and Sihulca archeological sites, with a minimum age for terrace construction of Cal 1 sigma AD 675-766 and 782-893 respectively; it remains unclear if another stage of construction. There is no evidence that the terraces have alternated between periods of cultural decline and boom. Rather, reconstructions or modifications to the original structure and the absence of paleosols, address to a continuous use until its abandonment. Today, they produce only under fallow-system. There are no archeological signs of massive irrigation systems (Reindel 2011, pers. comm.). Its installation could only be linked to more favorable climatic conditions, like those described for The Early Horizon (800-200 BC), The Early Intermediate Period (200 BC-600 AD), and The Late Intermediate (Period 1000-1438 AD) (Eitel et al. 2005, Mächtle 2007). As reported on other archeological sites in southern Peru (Branch et al. 2007), an extensive terrace agricultural system during the Middle Horizon (500-1000 AD) could be also attested in the Laramate area. Retention of eroded loessic material transported against the terrace walls could be associated to periods of increased geomorphodynamics founded in the surroundings by 600 AD (Forbriger & Schittek 2011, unpublished raw data). References Branch, N., Kemp, R., Silva, B., Meddens F., Williams, A., Kendall, A., Vivanco Pomacanchari, C. (2007): Testing the sustainability and sensitivity to climatic change of terrace agricultural systems in the Peruvian Andes: a pilot study. Journal of Archaeological Science 34 (2007) 1-9. Eitel, B., Hecht, S., Mächtle, B., Schukraft, G., Kadereit, A., Wagner, G. A., Kromer, B., Unkel, I., Reindel, M. (2005): Geoarchaeological evidence from desert loess in the Nasca-Palpa region, southern Peru: Palaeoenvironmental changes and their impact on Pre-Columbian cultures. Archaeometry 47, 137-185. Mächtle, B. (2007): Geomorphologisch-bodenkundliche Untersuchungen zur Rekonstruktion der holozänen Umweltgeschichte in der nördlichen Atacama im Raum Palpa/Südperu. Dissertation, Heidelberger Geographische Arbeiten 123.- 227 S.

  18. Etapas de fallamiento neógenas en la mitad occidental de la depresión de Ugijar (Cordilleras Béticas

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    Galindo Zaldívar, J.

    1986-02-01

    Full Text Available The geological structure of the western half of the Ugíjar Depression has been studied and the fauling of the intramiocene and later times is described in detail.
    The present contact zone between the Nevado-Filábrides and the Alpujárrides units (the Mecina Fault is shown to be a shallow-angled, dextral, transtensile fault. It can be determined from the associated rock deformations in the Nevado-Filábrides, such as extensional crenulation c1eavage, cataclasites and folding, that the upper block is moving towards SW-SSW. As far as the later structures are concerned the following stages have been distinguished: firstly, folding with an ENE axis. followed by normal dextral faults trending E to ENE, then reverse faults and thrusts with the upper block moving firstly towards the SE and then to the E, folding with an ENE axis normal dextral faults trending E to ENE, and finally the appearance of other small faults trending N to NW. The principal thrust shows ramps and flats and gives rise to fault rocks which may attain some ten metres in thickness. The intersections between thrusts and normal dextral faults, which occurred before and after these, form a complex zone of slices at the northern border of the Depression.
    Two hypotheses are proposed in order to explain the different stages of faulting. In the first, the structures might be the result of a dynamic evolution including a positional alteration in the in the stresses. In the second, which is geometrical in character, the structures may well be due to dextral, transtensile and strike-slip displacements along the convexities of the Mecina Fault.

    Se analiza la estructura de la mitad occidental de la Depresión de Ugíjar, individualizándose las etapas de fallamiento intramiocenas y posteriores.
    Se ha confirmado que el contacto actual entre Nevado-Filábrides y Alpujárrides es una falla de bajo ángulo transtentiva dextra (Falla de Mecina. A partir de las deformaciones asociadas que: se producen en los Nevado-Filábrides (clivaje de crenulación extensional. cataclasitas y pliegues se determina el movimiento del bloque de techo hacia el SW-SSW. Como estructuras posteriores se concluye una secuencia con las siguientes etapas: pliegues de eje ENE, fallas normales dextras de dirección E a ENE, fallas inversas y cabalgamientos con un desplazamiento del bloque de techo al SE y posteriormente hacia el E, pliegues de eje ENE, fallas normales dextras de dirección E a ENE, y, finalmente, otras fallas de pequeño salto con dimensión N a NW. El cabalgamiento (thrust principal tiene rampas y rellanos y genera roca de falla que pueden alcanzar el decámetro de espesor. Las intersecciones de cabalgamientos y fallas normales dextras anteriores y posteriores a ellos forman una zona de escamas compleja en el borde N de la Depresión.
    Se proponen dos hipótesis para explicar las etapas de fallamiento. En la primera, la sucesión de estructuras resultaría de una evolución dinámica con cambio posicional de los esfuerzos. En la segunda, de carácter geométrico, la sucesión de estructuras seria consecuencia de rejuegos transtensivos dextros y de salto en dirección según posibles convexidades de la Falla de Mecina.

  19. ESTATUS DE LA POBLACIÓN DE MONOS AULLADORES ROJOS EN EL CAÑÓN DEL BARBAS, FRAGMENTO MONTANO, CORDILLERA CENTRAL, COLOMBIA.

    Directory of Open Access Journals (Sweden)

    JORGE MARIO LONDOÑO

    2010-01-01

    Full Text Available Los bosques de montaña en Colombia han sufrido fuerte degradación por causas antrópicas y en la actualidad la mayoría son remanentes aislados e inmersos en hábitat antropogénicos. Los aulladores rojos han persistido en estas condiciones pero poco se conoce sobre su biología y respuesta a la alteración de su ambiente. Durante cinco meses en el 2005, evaluamos densidad y estatus poblacional de esta especie en la cuenca del río Barbas (departamentos de Quindío y Risaralda, fragmento aislado de bosque montano bajo de 790 ha. Estimamos la densidad empleando censos por transectos lineales repetidos. Adicionalmente seguimos tropas de aulladores y evaluamos variables de vegetación teniendo en cuenta los requerimientos ecológicos de la especie. Estimamos una densidad de 11,7±6 grupos y 132,1±68 individuos/km2, superior a la usualmente reportada en bosques continuos. Esta alta densidad probablemente se deba al aisla- miento del fragmento, que limita las posibilidades de dispersión de los aulladores. El tamaño promedio por tropa fue 11,3±2,5 individuos, con más de cinco machos y siete hembras adultas, y de uno a cuatro inmaduros. En general el bosque ofrece buena disponibilidad de recursos estructurales y alimenticios para los aulladores. Esta pobla- ción no se encuentra amenazada en la actualidad por actividades antrópicas. El frag- mento ha sido recientemente protegido bajo la figura de Parque Regional Natural y se adelantan corredores de conexión con otros remanentes cercanos. Sin embargo, esta población de aulladores se encuentra aislada de otras poblaciones y por tanto es urgente desarrollar medidas de manejo del paisaje para atenuar los efectos del aislamiento.

  20. Hydro-glaciological modeling in the Upper Maipo River basin, extratropical Andes Cordillera, with explicit representation of debris-covered glaciers.

    Science.gov (United States)

    McPhee, J. P.; Castillo, Y.; Escobar, M.; Pellicciotti, F.

    2014-12-01

    In this work we improve and calibrate a hydro-glaciological model based on a simplified energy balance approach using the WEAP modeling platform for two catchments in the headwaters of the Maipo River Basin, in the Andes Mountains of Central Chile. The Morales Creek catchment includes the San Francisco glacier, a clean glacier occupying 7% of the catchment area. The Pirámide catchment holds the debris-covered Pirámide Glacier, which covers 20% of the catchment area. Detailed field measurements have been carried out on both glaciers to characterize their melt and meteorological regimes. We calibrate an Enhanced Temperature Index melt model against ablation stakes and runoff measurements, and obtain clear differences between the optimal parameters for the clean and debris-covered glaciers. Calibrate melt threshold temperatures are 0,25 and 0,5ºC for the clean and debris-covered glaciers, respectively, while the fraction of net shortwave radiation employed for melting is 90 and 83% for clean and debris-covered glaciers, respectively. These results are coherent with an insulating effect of the debris cover at the Pirámide glacier. The hydrologic contribution of ice melt for the clean, San Francisco glacier is equivalent to 32% of total runoff measured at the Morales Creek outlet during the simulation period; on the other hand, ice melt accounts for 83% of total runoff estimated at the outlet of the Pirámide catchment over the same period. These results are part on an ongoing effort aimed at quantifying cryospheric contribution to the hydrology of the Maipo River basin, one of the key river basins in Chile, on the face of accelerated climate change, and is the first documented work to explicitly include debris-covered glaciers in a context of basin-wide hydrological modeling.

  1. Dinámica de elementos en epífitos de un bosque altoandino de la Cordillera Oriental de Colombia

    Directory of Open Access Journals (Sweden)

    Caballero Rueda Luis Martín

    1997-06-01

    Full Text Available The reserves and transfer of bioelements were studied during two years in the epiphytic bryophytes and the bromeliad Tillandsia compacta in a high Andean forest in Guisquiza, La Calera, Cundinamarca in the Eastern Andes of Colombia. Epiphyte biomass in this forest is 3766 kg/ha, ofwhich bryophytes contribute 55% and T.compacta, 9.3%. In relation to their biomass, these epihyttes store high quantities of water and nutrients and intercept materials washed from foliage, making them important to consider in watershed management. There are no significant differences in epiphyte element composition between soll and trees, or between size categories of T. compacta. Trapping of heavy elements in particular may mitigate contamination problems in diverse components of the ecosystem. T.compacta appears especially important as a regulator of potassium transfer, and therefore of cation exchange capacity of the system. These properties permit the epiphytes to be dampers of high acidity and of excess concentrations of Al, Fe and Mn common in montant ecosystems, which can be observed in the dynamic model presented.En un estudio del bosque alto andino de la vereda Guisquiza, La Calera (Cundinamarca, se analizaron las reservas y transferencia de bioelementos en briófitos y Tillandsia compacta Grisebach (Bromeliaceae, durante dos años. Las epífitas tienen una biomasa de 3766 Kg/ha en el bosque'; de este valor los briófitos son el 55 % Y T.compacta el 9.3 %. Para esta biomasa tan pequeña, resultan almacenar altas cantidades de agua, nutrientes y ser interceptoras de materiales de lavado foliar que las hacen valiosas para los planes de manejo y ordenación de cuencas. No hay diferencias entre los valores de los elementos epífitos del suelo con respecto a los de los arboles; igualmente entre las categorfas de T.compacta. El trampeo de elementos especialmente, los pesados, disminuye los problemaspor intoxicación en los diversos componentes del ecosistema. T. compacta resalta como reguladora de elementos de cambio en especial de potasio y por ende de la capacidad de intercambio catiónico (CIC del sitio. Así mismo, estas propiedades les permite ser amortiguadoras de la alta acidez y de los daños por exceso de concentración de Al, Fe y Mn comunes en los orobiomas o ecosistemas de montaña. Lo cual es observable en el modelo de dinámica planteado.

  2. Dinámica de elementos en epífitos de un bosque altoandino de la Cordillera Oriental de Colombia

    OpenAIRE

    Caballero Rueda Luis Martín; Rodríguez Nelly; Martín Carlos

    1997-01-01

    The reserves and transfer of bioelements were studied during two years in the epiphytic bryophytes and the bromeliad Tillandsia compacta in a high Andean forest in Guisquiza, La Calera, Cundinamarca in the Eastern Andes of Colombia. Epiphyte biomass in this forest is 3766 kg/ha, ofwhich bryophytes contribute 55% and T.compacta, 9.3%. In relation to their biomass, these epihyttes store high quantities of water and nutrients and intercept materials washed from foliage, making them important to ...

  3. Aspectos sismológicos y morfotectónicos en el extremo occidental de la Cordillera Volcánica Central de Costa Rica

    OpenAIRE

    Alvarado, Guillermo E.; Morales, Luis Diego; Montero, Walter; Climent, Alvaro; Rojas, Wilfredo

    2011-01-01

    An historical seismicity study in the near vicinity of Poas volcano (Central Volcanic Range), shows that five local, intermiate magnitude (5 < M ≤ 6.5), shallow focus (h < 20 km) earthquakes had affected these area, whith Mercalli Modified intensities between VII and IX grades. The earthquakes that occured on August 28, 1911, June 6, 1912 and September 1, 1955 had its focus approximately 5 km to the Southeast of the small town Bajos Toro. The remain two eartquakes that occurred on March 18, 1...

  4. Estilos de Apego en Relaciones de Pareja y su Asociación con la Satisfacción Marital Attachment Styles in Couples and Their Association With Marital Satisfaction

    National Research Council Canada - National Science Library

    Mónica Guzmán; Paula Contreras

    2012-01-01

    ... interacción entre el estilo de apego propio y el de la pareja sobre la satisfacción en 129 participantes y sus respectivas parejas, provenientes de la ciudad de Antofagasta, Chile. Se realizó...

  5. Estudios ecológicos en la Cordillera Oriental colombiana III. - La vegetación de la cuenca del lago de Tota (Boyacá) Estudios ecológicos en la Cordillera Oriental colombiana III. - La vegetación de la cuenca del lago de Tota (Boyacá)

    OpenAIRE

    Rangel Ch. Orlando; Aguirre C. Jaime

    1986-01-01

    In the river basin of the Tota lake (Boyacá) there are two differents zones related to the geomorphology, soil and climate. In the noreast zone the ecological conditions allow that the vegetation shows a greater cover; in the norwest zone on the other hand these conditions are very drastic, the floristic composition of vegetation is poor and generally speaking the landscape is of "arid type".  The distribution of vegetation in the river basin is caused by topographic variations (altitude, reI...

  6. Estudios ecológicos en la Cordillera Oriental colombiana III. - La vegetación de la cuenca del lago de Tota (Boyacá Estudios ecológicos en la Cordillera Oriental colombiana III. - La vegetación de la cuenca del lago de Tota (Boyacá

    Directory of Open Access Journals (Sweden)

    Rangel Ch. Orlando

    1986-12-01

    Full Text Available In the river basin of the Tota lake (Boyacá there are two differents zones related to the geomorphology, soil and climate. In the noreast zone the ecological conditions allow that the vegetation shows a greater cover; in the norwest zone on the other hand these conditions are very drastic, the floristic composition of vegetation is poor and generally speaking the landscape is of "arid type".  The distribution of vegetation in the river basin is caused by topographic variations (altitude, reIief and by differences of climate (temperature and solar radiation. Around the lake, the soil-content of water and nutrients, the physiography and the wind-action in some cases determine of the arrangement of plants-associations. These units of vegetation (associations are described following the Zurich-Montpellier school and the rules and recomendations of the Code of Phytosociological Nomenclature (BARKMAN et at.. 1976.  Among these units are the: forest of Alnus acuminata subsp.  acuminata which grow on moist and marsh places around the lake and the sparse scrub with Hypericum ruscoides and Plantago monticola ond dry places.  In the "Páramo-región", the dense scrub with Brachyotum striqosum and Celamaqrostis effusa and the stemrosette communities with Espeletia lopezii were studied.  The "life-form" spectrum (RAUNKIAER, en BRAUN-BLANQUET, 1979 and the leaf characters (size, consistency, indumentation for each association also are provided. En la geomorfología y en el clima de la cuenca del lago de Tota, se diferencian dos regiones: nor-oriental y nor-occidental. En la primera las condiciones ecológicas son favorables y permiten una mayor cobertura y diversidad de la vegetación; la región nor-occidental por el contrario, esta sujeta a condiciones ecológicas drásticas, muestra una vegetación muy pobre y en general el paisaje es de tipo "árido".  La preliminar caracterización de los suelos, indica que en su mayoría, estos son bastante pobres en nutrientes, muy desaturados, con pH ácidos y están sometidos a continuos lavados. La distribución de la vegetación en la cuenca, obedece esencialmente a variaciones topográficas (altitud, relieve y a cambios climáticos asociados, como la temperatura y la radiación solar. En los alrededores de la masa de agua, entre 3.000 y 3.150 m, las fluctuaciones en el contenido de agua en el suelo, la calidad del sustrato en cuanto a nutrientes, la fisiografía y la acción del viento en casos muy particulares son los factores responsables de la disposición de las unidades de vegetación que se inventariaron.  Estas unidades se estudiaron según las recomendaciones metodológicas de BRAUN-BLANQUET (1979 y comprenden desde el Viburno-Alnetum acuminatae o  bosques marginales sobre sitios con buen contenido de agua en el suelo, a continuación de la vegetación de ribera o Polygono-Scirpion californici RANGEL &: AGUIRRE 1983, con dominio de Alnus acuminata subsp. acuminata, hasta el Plantaqini-Hypericetum Ruscoidis o matorrales ralos, sobre sitios pedregosos y muy secos.  En la región paramuna, se inventariaron matorrales del Brachyoto-Calamaqrotietum effusae y "frailejonales" con Espeletia  lopezii. Las unidades de vegetación se describieron de acuerdo con el Código Internacional de Nomenclatura Fitosociológica (BARKMAN et al., 1976. Se realizaron también los análisis de las formas de vida (RAUNKIAER en BRAUN-BLANQUET 1979 y de las características foliares, las cuales permitieron diferenciar tendencias en los fitoclimas y en la textura de la vegetación en cada asociación reseñada.

  7. Estudios ecológicos en la Cordillera Oriental – II: Las comunidades vegetales de los alrededores de la laguna de Chingaza (Cundinamarca Estudios ecológicos en la Cordillera Oriental – II: Las comunidades vegetales de los alrededores de la laguna de Chingaza (Cundinamarca

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    Franco R. Pilar

    1986-12-01

    Full Text Available The plant communities present along an altitudinal transect between 3.000-3.600 m above sea level around Chingaza lake, Cundinamarca, Colombia, are described following the Zurich-Montpellier System. The zonal plant communities (WALTER. 1964 belong to the life zones refered to as "Paramo" and "Andean" by CUATRECASAS (1934, 1958 and RANGEL et al., (1982.  The azonal plant communities (marsh communities are briefly studied.  New information about synecological aspects and geographic distribution is provided together with a provisional sintaxonomic classification of the vegetation of the area. Mediante la utilización de los lineamientos metodológicos de la Escuela, Zurich-Montpellier, se tipifican y describen las comunidades vegetales de los alrededores de la Laguna de Chingaza (Cundinamarca entre 3.000 y 3.600 m.  Las comunidades zonales (WALTER, 1964 se pueden ubicar según los esquemas propuestos por CUATRECASAS (1934, 1958  y por RANGEL et al., (1982 en las zonas de vida Paramuna y Andina (franja alto-andina; la vegetación azonal (de pantano también se reseña.  Igualmente se presenta información adicional que incluye aspectos sinecológicos y corológicos y se propone un arreglo sintaxonómico provisional de la vegetación estudiada.

  8. A LA SOMBRA DEL ESTADO: COMUNALIZACIÓN INDÍGENA EN PARAJES DE LA PRE CORDILLERA DE RÍO NEGRO, ARGENTINA / In the shadow of the state: Indian communalization in sites from the Rio Negro province pre Cordillera, Argentina

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    Lorena Cañuqueo

    2015-12-01

    Full Text Available Nos proponemos analizar un proceso de comunalización situado en parajes rurales de la cuenca del arroyo Comallo, provincia de Río Negro. En agosto de 2011 se conformó formalmente allí la comunidad mapuche Newen Ñuke Mapu que pasó a integrarse a las comunidades denominadas “nuevas” en la provincia, por contraste con aquellas consideradas “tradicionales”. Nuestro argumento es que esa novedad no es tal, sino que subyace un proceso de comunalización de larga duración que ha estado en permanente disputa con políticas estatales atomizadoras. En este sentido, se trata de un colectivo que se ha desarrollado a la sombra del estado argentino. Comenzaremos con un recorrido histórico en función de ubicar este caso en el proceso de incorporación del pueblo mapuche al estado nacional. A continuación analizamos el proceso de comunalización en tres escenarios históricos anclados en crisis de diferente tipo. 1 El presente que retoma la conformación de la comunidad mapuche. A partir de este aparecen como instancias de referencia consideradas fundantes de lo colectivo dos momentos históricos anteriores. 2 1984, periodo en el que se conforman las cooperativas laneras, entre otras formas de organización indígena. 3 1930, crisis que marcó el avance de la propiedad privada en la zona y que implicó estrategias de visibilización y demanda dirigidas al estado.  AbstractIn this article we intend to analyze a process of communalization located in the rural areas of the province of Río Negro. In August 2011 the Mapuche community Newen Ñuke Mapu came formally into existence. Since then on it became one more of the “new” indigenous communities in contrast to those acknowledge as “traditional”. Our argument is that there is no such novelty but there is an underlying long term process of communalization that has been in constant dispute with state policies. In this sense, we describe it as a grouping that has developed at the shadow of the state. We begin by laying out the historical process of incorporation of the Mapuche people to the national state in order to situate this particular case. Then, we discuss the process of communalization on three historical scenarios anchored in three different types of crises.

  9. Biostratigraphy and assemblage evolution in Planktic Foraminifera across the Cretaceous-Paleogene transition in low latitude, northern and southern Tethys realm: El Kef GSSP, Elles (Tunisia) and Agost, Caravaca (Betic Cordillera, Spain)

    Science.gov (United States)

    Gallala, N.; Zaghbib-Turki, D.; Turki, M. M.; Arenillas, I.; Arz, J. A.; Molina, E.

    2009-04-01

    The detailed planktic foraminiferal biostratigraphic and quantitative study from the Cretaceous-Paleogene (K-Pg) transition interval of the most expanded and continuous sections located in Spanish (Agost, Caravaca) and Tunisian sections (El Kef and Ellès), allows us to establish the zonation and subzonation of this interval and to distinguish four Acme-stages across the K/Pg transition interval of these low latitude sections. The uppermost Maastrichtian in Tunisian and Spanish sections, is characterized by standard planktic foraminiferal zones: Abathomphalus mayaroensis subdivided into Plummerita hantkeninoides Subzones. This index species is absent at middle and high-latitude twice in Atlantic and Antarctic oceans. Consequently, this species is considered to be restricted to the tropical and subtropical deep seawater. The lower Danian is characterized by Guembelitria cretacea, Parvularugoglobigerina eugubina, and Parasubbotina pseudobulloides biozones. The Guembelitria cretacea Zone was subdivided into the Hedbergella holmdelensis and Parvularugoglobigerina longiapertura Subzones; the Parvularugoglobigerina eugubina Zone into the Parvularugoglobigerina sabina and Eoglobigerina simplicissima Subzones; and the Parasubbotina pseudobulloides Zone into the Eoglobigerina trivialis and Subbotina triloculinoides Subzones. These zones and subzones are less expanded at the Caravaca and Agost sections than in Tunisian sections: El Kef (Global Stratotype Section and Point for the K/Pg) and Ellès, but it is sufficiently expanded to analyze correctly the planktic foraminiferal assemblage evolution across the K-Pg transition. Across this transition, at the Tethys area, we have identified four Acme-stages: Acme-stage 0: is typical of the upper Maastrichtian interval is dominated by cosmopolitan species dwelling surface and intermediate seawater. Acme-stage 1: is typical of the G. cretacea Zone and is dominated by Guembelitria species belonging to "Cretaceous survivors" species. Acme-stage 2: spans the Pv. eugubina Zone dominated mainly by specimens belonging to Palaeoglobigerina and Parvularugoglobigerina genera. Acme-stage 3: It spans the Ps. pseudobulloides Zone and dominated by biserial species belonging to Chiloguembelina and Woodringina genera. The turnover in Tethys realms after the K/Pg mass extinction, characterized the lower Danian interval and occurred in three episodes, recorded as planktic foraminiferal acme-stages (1 to 3). This succession of distinct Acme-stages is comparable with those recognized at Atlantic realms.

  10. La sección de Torrellano (Mioceno Superior – Plioceno, Cuenca del Bajo Segura, Cordillera Bética Oriental): estratigrafía general y bioestratigrafía mediante foraminíferos planctónicos

    OpenAIRE

    Peral Lozano, Juan

    2016-01-01

    En este trabajo se estudia la sección estratigráfica de Torrellano, ubicada en el sector norte de la cuenca neógena del Bajo Segura. El objetivo del mismo es ilustrar los rasgos estratigráficos de los sintemas Tortoniense-Messiniense I (T-MI), Messiniense II (MII) y Plioceno (P) de la sección estudiada. Además se ha realizado un análisis bioestratigráfico mediante foraminíferos planctónicos del sintema T-MI, que resulta clave para precisar, por un lado las condiciones ambientales que reinaron...

  11. EL DESARROLLO DE CAPACIDADES Y SU INFLUENCIA EN EL DESARROLLO DE LAS OPERACIONES DE DESMINADO HUMANITARIO EN LA CORDILLERA DEL CNDOR (Development of Capabilities for the Conduct of Humanitarian Demining Operations in the Condor Mountain Range)

    Science.gov (United States)

    2017-06-01

    designada con la finalidad de facilitar la conducción de las ODH a cargo de la DIGEDEHUME y dar cumplimiento al Plan Nacional de Desminado...Estructura Ocupacional Militar (MOCS); Desarrollo del Plan de Bases de Emisión (BOIP); Documentos de Desarrollo de Capacidad (CDD); Proceso FDU (incluye... Nacionales de Desminado Humanitario.73 Como se puede apreciar con respecto al inciso 2, aumento de la capacidad nacional , el Estado colombiano trabaja en

  12. A new minute species of Pristimantis (Amphibia: Anura: Craugastoridae) with a large head from the Yanachaga-Chemillén National Park in central Peru, with comments on the phylogenetic diversity of Pristimantis occurring in the Cordillera Yanachaga

    Czech Academy of Sciences Publication Activity Database

    Lehr, E.; Moravec, J.; Cusi, J. C.; Gvoždík, Václav

    2017-01-01

    Roč. 325, June (2017), s. 1-22 ISSN 2118-9773 Institutional support: RVO:68081766 Keywords : Andes * DNA barcoding * frogs * molecular phylogeny * new species Subject RIV: EG - Zoology Impact factor: 0.649, year: 2016

  13. Revisión del género Cantabrogeus Salgado, 2000, con la descripción de tres nuevas especies hipogeas endémicas de la Cordillera Cantábrica (Coleoptera, Leiodidae, Cholevinae, Leptodirini

    Directory of Open Access Journals (Sweden)

    Salgado, J. M.

    2012-06-01

    Full Text Available A revision of the genus Cantabrogeus Salgado, 2000, with description of three new hypogean species endemic to the Cantabrian mountains (Coleoptera, Leiodidae, Cholevinae, Leptodirini The two previously known species of the genus Cantabrogeus (Coleoptera, Leiodidae, Cholevinae, Leptodirini are redescribed, and three new species are described: Cantabrogeus antimachus n. sp., C. cultellus n. sp. and C. fresnedai n. sp. One of these (C. antimachus n. sp. is tripliod (3n = 33 and the first known parthenogenetic species of Leiodidae. The relationships between the different taxa are discussed based on external morphological characters and the structure of male and female genitalia, as well as the distribution of the species in the different areas in the Cantabrian mountains (NW Iberia. Analyses of molecular data (fragments of seven mitochondrial and nuclear genes confirms the monophyly of Cantabrogeus and its sister–group relationship with Fresnedaella, as well as its inclusion within the paraphyletic series Quaestus. The parthenogenetic species (C. antimachus n. sp. has a derived position within Cantabrogeus, which, according to previous estimates of the molecular rate, probably diversified during the Pliocene–Pleistocene in the Cantabrian karst areas, of a high tectonic complexity.

  14. Aportaciones al conocimiento de la compresión tardía en la Cordillera Ibérica centro-oriental: la cuenca neógena inferior del Mijares (Teruel-Castellón

    Directory of Open Access Journals (Sweden)

    Paricio Cardona, J.

    1986-10-01

    Full Text Available The lower Neogene deposits of the Mijares valley (mainly fluvial facies are filling three paralell• grabens controlled by synsedimentary ENE normal faults. This structural pattern is created during a moderate compression phase with an ENE horizontal σ1 axis which sometimes can be permuted with the vertical σ2. Afterwards. a second SSE to S compression affects these deposits. The age of the basin can be established in the Upper Aragonian-Lower Vallesian bested on the Micromamal fauna found in two localities. Other sites in the cetral-oriental lberian Chain also show compressive deformations in well-dated deposits of Agenian and Aragonian ages. The compression still continues in this region during the Lower and Middle Miocene, the passage to the extension regime talking place in the Vanesian.

    Las facies esencialmente fluviales que integran la unidad interior~ del valle medio del Mijares se depositan en tres grabens paralelos controlados por fallas sinsedimentarias ENE de componente normal. Este dispositivo estructural se crea en el curso de una etapa. compresiva de intensidad moderada, con un σ1 según ENE, que eventualmente se intercambia con σ2 vertical. Una segunda etapa de compresión SSE a S afecta posteriormente a esta unidad, datada en el Astaranciense-Vallesiense gracias a la fauna de micromamíferos proporcionada por dos yacimientos. Otras localidades de la Cadena Ibérica centro-oriental registran asimismo deformaciones compresivas en depósitos bien datados entre el Ageniense y el Aragoniense. Aunque sin producir apenas pliegues, el régimen compresivo perdura aún claramente en este sector de la cadena durante toda la primera mitad del Mioceno, siendo en el Vallesiense cuando se produce el tránsito definitivo a la distensión.

  15. Geochemistry and geochronology from Cretaceous magmatic and sedimentary rocks at 6°35‧ N, western flank of the Central cordillera (Colombian Andes): Magmatic record of arc growth and collision

    Science.gov (United States)

    Jaramillo, J. S.; Cardona, A.; León, S.; Valencia, V.; Vinasco, C.

    2017-07-01

    The spatio-temporal, compositional and deformational record of magmatic arcs are sensible markers of the long-term evolution of convergent margins including collisional events. In this contribution, field relations, U-Pb LA-ICP-MS zircon geochronology from magmatic and sedimentary rocks, and whole-rock geochemistry from volcanic and plutonic rocks are used to reconstruct the Cretaceous arc growth and collision in the awakening of the Northern Andean orogeny in northwestern Colombia. The Quebradagrande Complex that includes a sequence of volcanic rocks intercalated with quartz-rich sediments is a tholeiitic arc characterized by an enrichment in LREE and Nb-Ti anomalies that document crustal thickening in an arc system that was already active by ca. 93 Ma. This arc was built associated with thin continental and newly formed oceanic crust, as suggested by the presence of Triassic and older detrital zircons in the associated sandstones. This fringing arc subsequently experienced deformation and a major switch to and enriched calc-alkaline high-k plutonism between 70 and 73 Ma. The deformation record and changes in composition are related to an opposite double-vergence Molucca-sea type arc-arc collision that ended with the accretion to the continental margin of an allochthonous island arc built on an oceanic plateau associated with the Caribbean plate. The new time-framework suggest that the Late Cretaceous to Paleocene collisional tectonics include various stages before the switching to a subduction-dominated regime in most of the Cenozoic.

  16. Fábricas y texturas miloníticas. Cinemática de las traslaciones en el complejo Nevado-Filábride (Cordilleras Béticas, España

    Directory of Open Access Journals (Sweden)

    Martínez, J. M.

    1986-10-01

    Full Text Available In the Nevado-Filábride Units of the Eastern Sierra Nevada, the main structure is a mylonitic foliation with a strong stretching lineation. The trend of this 1ineation shows a bimodal orientation resulting from two successive phases of deformation (D2, N80E and D3, NI45E.
    A comparative study of the structures and microestructures developed in both phases is presented. The relations between metamorphism and deformation are also considered.
    A kinematic analisis of the Nevado-Filábride displacements from the c-axis fabrics of quartz is induded. Microstructures and crystallographic preferred orientations of quartz suggest that quartzites were deformed by intracrystalline plasticity with dislocation creep.
    A first conclusion suggest that the Nevado-Filábride pile is attained after- two main stages of thrusting. In the first, a major intra-crustal shear zone separating the Mulhacén Nappe (high presure and moderate temperature metamorphism from the underlying Veleta Nappe (low presure and low temperature metamorphism is developed. In the second one the former pile is disturbed and the imbrication of the units belonging to the upper part of the Complex occurred.

    En las Unidades Nevado-Filábrides de Sierra Nevada Oriental, la estructura principal es una foliación milonítica con una lineación de estiramiento muy pronunciada. La dirección de esta lineación muestra una orientación bimodal, como resultado de dos fases de deformación sucesivas (D2, N80E y D3, NI45E.
    Se hace un estudio comparativo de las estructuras y microestructuras desarrolladas en ambas fases. Se consideran también las relaciones metamorfismo-deformación.
    Se incluye un análisis cinemático de las traslaciones Nevado-Filábrides partir de fábricas de ejes «c» de cuarzo. Las microestructuras y las orientaciones cristalográficas preferentes del cuarzo indican que las cuarcitas se han deformado por plasticidad intracristalina con movimiento de dislocación.
    Se concluye que la pila de materiales Nevado-Filábrides se consigue en dos etapas de cabalgamiento principales. Una de escala cortical, en la que se superponen las rocas del Manto del Mulhacén (metamorfismo de alta presión y temperatura moderada sobre las del Manto del Veleta (metamorfismo de baja presión y temperatura. Y otra posterior, en la que se modifica la pila anterior y tienen lugar las repeticiones de unidades en la parte alta del Complejo.

  17. The E-W segments of the contact between the external and internal zones of the Betic and Rif cordilleras and the E-W corridors of the internal zone (a combined explanation

    Directory of Open Access Journals (Sweden)

    Sanz de Galdeano, C.

    1996-08-01

    Full Text Available The contact between the Internal Betic-Rif Zone and the corresponding external zones is not regular, sorne sections having a NNE-SSW direction and others approximately EW. These latter coincide with sorne of the corridors of the Internal Zone, and have continuity with those within this zone. A model which relates the two features is proposed, in which the corridors originally corresponds to faults or fault zones which are the eastern continuation of the transcurrent contacts, by means of which the Internal Zone advanced westwardly more easily on its collision with the External Betic Zone. This means that the Internal Zone is divided into various cortical segments and advanced towards the west. The proposal of the model ineludes a discussion of the Alpujarras and Colmenar corridors, which continue each other, and provides values for the displacement of the zone of faults. With this model, both the transcurrent E-W fauits of the Internal Zone, as well as at least part of the extensional movements affecting this zone, remain subordinate to the shifting of the Internal Zone towards the west.El contacto entre la Zona Interna Bético-Rifeña y las correspondientes zonas externas no es regular. Muestra unos sectores de dirección NNE-SSW y otros que son aproximadamente E-W; estos últimos coinciden con algunos de los corredores de la Zona Interna y están en continuidad con los que existen dentro de la misma. Se propone un modelo en el que se relacionan genéticamente ambos rasgos, de manera que los corredores corresponden originalmente a fallas o zonas de fallas que son la continuación de los contactos transcurrentes más occidentales, por medio de los cuales la Zona Interna ha logrado avanzar con más facilidad hacia el W en su choque con la Zona Externa Bética. Esto significa que la Zona Interna está dividida en varios segmentos corticales y que el avance de la misma se hizo fundamentalmente hacia el W. En la propuesta del modelo se discuten los corredores de las Alpujarras y de Colmenar, situados en continuidad mutua, y se dan los valores de desplazamiento del conjunto de las fallas. Con este modelo, tanto las fallas transcurrentes E-W de la Zona Interna, como al menos parte de los movimientos extensionales ocurridos en la misma, quedan subordinados a la traslación de la Zona Interna Bético-Rifeña hacia el W.

  18. Relaciones entre la zonalidad petrológica y metalogénica de los macizos lerzolíticos de las cadenas alpinas del Mediterráneo Occidental (Cordillera Bético-Rifeña y Kabylias

    Directory of Open Access Journals (Sweden)

    Torres-Ruiz, J.

    1988-12-01

    Full Text Available Gamet-lherzolite facies, Ariegite and Seiland subfacies of the spinel-lherzolite facies and plagioclase-lherzolite facies have been identified in the Serranía de Ronda, Beni Bousera and Collo lherzolitic massifs. These petrological facies occur in a zonal arrangement: gamet lherzolite are in contact with the overlaying metapelitic sequence and spinel then plagioclase lherzolite occur inwards, representing the innermost zones in the former mantle body. The various occurrences of mineralizations can be classified in two main groups: one of them is essentialIy made up of chromite and Ni arsenides with pyroxene and/or cordierite as gangue minerals; the other consists Qf Fe-Ni-Cu sulfides and graphite, with pyroxene, plagioclase and phlogopite as gangue minerals. In both groups, the ores with the more refractory composition were the first to crystallize in the hotter core of the diapir while those other with a more differentiated composition were formed later within the external zones. The close correlation between petrological and metallogenical roning supports a magmatic origin of the mineralizations related to the petrologic evolution of the mantle bodies. The mineralizing liquids• originated from magmas generated by partial melting of the peridotites. The former migrated outwards, from the internal part of the bodies, during which marked interaction with the enclosing rocks and complex fractionation processes took place under moderate to low pressure conditions.En los macizos lerzolíticos de la Serranía de Ronda, de Beni Bousera y de Collo se han identificado facies de lerzolitas con granate, facies de lerzolitas con espinela (subfacies Ariegita y Seiland y facies de lerzolitas con plagioclasa. Estas facies petrológicas se distribuyen de forma que las lerzolitas con granate se sitúan en contacto con la unidad metapelítica suprayacente, mientras que las lerzolitas con espinela y con plagioclasa lo hacen en posiciones progresivamente más alejadas, representando zonas cada vez más internas en el primitivo cuerpo ultramáfico. Los diferentes indicios de mineralización pueden dividirse en dos grupos: uno compuesto esencialmente por cromita y arseniuros de níquel con ganga de piroxenos y/o cordierita, y el otro constituido por sulfuros de Fe-Ni-Cu con grafito y con piroxenos, plagioclasa y flogopita como minerales de la ganga. En ambos grupos las mineralizaciones de composición más refractaria son las primeras en cristalizar y lo hacen en las etapas más tempranas en las zonas más internas del diapiro, mientras que las de composición más diferenciada lo hacen más tarde en posiciones más periféricas. La fuerte interrelación entre la zonación petrológica y metalogénica apoya una génesis para las mineralizaciones íntimamente asociada a la evolución petrológica de los diapiros del manto. Los líquidos mineralizantes derivan de magmas generados mediante la fusión parcial de las peridotitas y habrían migrado hacia la periferia sufriendo un complejo proceso de fraccionación e interacción con las rocas encajantes, en condiciones de presión moderadas a bajas.

  19. Structural analysis and shape-preferred orientation determination of the mélange facies in the Chañaral mélange, Las Tórtolas Formation, Coastal Cordillera, northern Chile

    Science.gov (United States)

    Fuentes, Paulina; Díaz-Alvarado, Juan; Fernández, Carlos; Díaz-Azpiroz, Manuel; Rodríguez, Natalia

    2016-04-01

    This study sheds light on the tectonic and structural knowledge of the mélange facies located to the south of Chañaral city, Chile. The Chañaral mélange has been related to an accretionary prism at the western active continental margin of Gondwana. Based on the fossil content, the original turbidite sequence would have been deposited during Devonian to Carboniferous times. The Chañaral mélange is included in the Las Tórtolas Formation, which corresponds to the Paleozoic metasedimentary basement located in the Coastal Range in northern Chile. It consists of a monotonous sequence of more than 90% of interbedded sandstones and shales, with a few limestones, pelagic chert, conglomerates and basic volcanic rocks, metamorphosed to the greenschist facies. In the study area, the Las Tórtolas Formation is divided into two structural domains separated by a major reverse dextral structure, called here the Infieles fault. To the east, the Las Tórtolas Formation is characterized by a brittle-ductile deformation, defined by the original sedimentary contacts in the turbiditic sequence. Besides, thrust faults and associated thrust propagation folds promotes a penetrative axial plane foliation. Mélange facies are located to the west of the Infieles fault. Although lithologies comprising this domain are similar to the rest of the Las Tórtolas Formation, mélange facies (ductile domain) are characterized by the complete disruption of the original architecture of the turbidite succession. The most significant structures in the mélange are the ubiquitous boudinage and pinch and swell structures, asymmetric objects, S-C structures and tight to isoclinal folds. This deformation is partitioned in the Chañaral mélange between linear fabric domains (L), characterized by quartzite blocks with prolate shape in a phyllite matrix with pencil structures, and linear-planar fabric domains (L-S), where quartzite objects show oblate shape and phyllites present a penetrative foliation. The intensity of deformational process is reflected in the high aspect ratios yielded by the quartzite constrictive (L) and flattened (L-S) object axes. Meso-scale shape preferred orientation (SPO) has been compared with quartz microtextures in quartzite blocks, resulting aspect ratios considerably lower than those obtained from the mesoscopic fabric. Main deformation mechanism observed in quartz microtextures are bulging-subgrain rotation recrystallization and dissolution-precipitation creep for pure and impure quartzites respectively. The temperatures deduced from these microtextures are between 350 and 400 °C, which coincides with the greenschists facies metamorphism observed in the Las Tórtolas and the mélange facies. Extremely dissociation between micro- and meso-scale deformation could be generated by dissolution at high differential stress in the boundaries of the quartzite layers and precipitation at low differential stress parts, which would increase the aspect ratio of the lenses whereas internally, quartz would have remained virtually unstrained. We propose here a tectonic setting for the Chañaral mélange formation based on the geodynamic evolution of the western active margin of South America during Late Paleozoic to Early Jurassic. Thus, the study area is located in a LT-HP zone of an accretionary complex, where rocks from the subduction channel (mélange facies) and the basal domain of the prism (brittle-ductile domain of the Las Tórtolas Formation) are in contact through the Infieles fault.

  20. Estructura y organización de las coladas submarinas: características de las lavas almohadilladas de edad cretácica que afloran en la Cordillera Vasco- Cantábrica

    Directory of Open Access Journals (Sweden)

    Alonso, A.

    1999-12-01

    Full Text Available In the Basque-Cantabrian Basin, an important submarine volcanic activity of alkaline character was developed during the upper Cretaceous. This vulcanism was related to a rift and/or transform fault in the continental crust associated to the opening of the North Atlantic ocean. Pillow lava flows are noteworthy among the other volcanic materials by their volume and excellent preservation state. The lava flows are formed by the pile up of small flow-and cooling units, i.e. tubes or lava tubes, characterized by: i coarse cylindrical morphology with abundant constrictions, ii diameter less than 1 meter in a transversal section, iii smooth or striated surface, iv concentric and/or radial internal structure, and iv the branches and direction changes during the outflow. Lava flows/tubes shape and surface characteristics depend on the viscosity, effusion rate and the thickness of quenched crust during growth. The Tubes are moted directly on feeder dykes or are connected in tabular flows. The expanding and advancement of the tubes was the result of stretching or breaking of the quenched surface crust and spreading of the molten lava from the interior. Stretching features and cracks appear mainly at the flow front, but lobes of lava developed from the top and the flanks of the tubes are not uncommon. Only scarce pillowed lavas are truly isolated magma sacks separated from their sources. Related to the tabular flows and the biggest pillow lavas, some breccias were occasionally formed by the gravitational collapse of the roof of the draining tunnels.Durante el Cretácico superior se desarrolló en la Cuenca Vasco-Cantábrica una importante actividad volcánica submarina de naturaleza alcalina. Este vulcanismo estuvo relacionado con el funcionamiento de un rift y/o una falla transformante en corteza continental asociado a la apertura del Atlántico Norte. Entre los productos volcánicos destacan, por su notable volumen y excelente grado de preservación, las coladas de lavas almohadilladas. Estas coladas están formadas por el apilamiento de pequeñas unidades de flujo y enfriamiento, denominadas tubos de lava, caracterizadas por presentar: i morfología groseramente cilíndrica con estrechamientos sucesivos, ii sección transversal de diámetro normalmente Los tubos están enraizados directamente en diques de alimentación o entroncados en coladas tabulares. Se propagan por la liberación del fundido en su frente de avance, parte superior o flancos a través de fracturas abiertas en una corteza superficial gruesa y rígida, o bien por el estiramiento de una corteza fina y plástica. Sólo unas pocas lavas almohadilladas son verdaderos sacos aislados de magma separados de sus fuentes. En relación tanto con las coladas tabulares como con las pillow lavas de mayor tamaño, se encuentran en ocasiones brechas formadas por el desplome gravitatorio del techo de túneles de drenaje.

  1. Dinámica del daño foliar en plántulas de Drimys granadensis (Winteraceae y Clusia multiflora (Clusiaceae en el bosque altoandino de la Cordillera Oriental colombiana

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    Carolina Ramos

    2008-09-01

    Full Text Available Además de las estrategias fitoquímicas especializadas, las plantas pueden usar la producción sincrónica de hojas como un método de saciado de patógenos y herbívoros. Con el fin de determinar si las especies del bosque altoandino colombiano Clusia multiflora (Clusiaceae y Drimys granadensis (Winteraceae recurren a la producción sincrónica de hojas para controlar los efectos de la herbivoría y el ataque microbiano, y establecer que relación existe entre el estado de salud, el crecimiento y la mortalidad de plántulas, se evaluó la dinámica del daño foliar sobre diferentes cohortes. Dado que una plántula tolerante a la sombra recientemente emergida no puede suplir los costos fisiológicos de una estrategia especializada, se esperaba una alta sincronía en la producción de hojas en las plántulas más jóvenes, y diferencias en el daño foliar entre cohortes. Se midieron cuatro variables que evaluaban el estado de salud a lo largo del tiempo, en tres cohortes de plántulas: Proporción de hojas predadas, proporción de hojas sanas, proporción de hojas enfermas o con daño puntual y crecimiento. Ambas especies mostraron diferencias significativas entre épocas, en la proporción de hojas sanas; pero no hubo un efecto de la interacción tiempo-cohorte, por lo tanto la producción sincrónica de hojas no fue una estrategia más usada por alguna cohorte en particular. El daño foliar osciló a través del tiempo, lo cual puede ser explicado por los pulsos en la producción de hojas. Sin embargo, ésta estrategia tuvo poca eficiencia para controlar el ataque por patógenos. En general, el comportamiento unificado de todas las variables fue afectado por la cohorte, el tiempo, la especie y todas las diferentes interacciones. La relación entre crecimiento y daño foliar fue condicionado por el clima. La mayor mortalidad se dio durante la estación seca, y un cuarto de las muertes en D. granadensis fueron causadas por la acción conjunta de herbivoría y sequía. Los resultados sugieren que a pesar de la producción sincrónica de hojas en todas las cohortes, fue poca la eficiencia para controlar el daño foliar, ya que las medias de Ps estuvieron por debajo de 0.25 al final del seguimiento. Las diferencias en la dinámica del estado de salud entre especies podrían explicar parcialmente la coexistencia en el bosque altoandino.Leaf damage dynamics of Drimys granadensis (Winteraceae and Clusia multiflora (Clusiaceae seedlings in the High-Andean Forest. Because of their slow growth, shade-tolerant species remain exposed to foliar damage long before reproductive age. Foliar damage can be controlled through synchronous leaf production and specialized phytochemical strategies. in this study, the dynamics of foliar damage in different cohorts of seedlings were evaluated to determine if the High-Andean species, Clusia multiflora (Clusiaceae and Drimys granadensis (Winteraceae appeal to the synchronous leaf production for controlling the herbivory and pathogenical damage, and to establish the possible relations between the healthy state, growth and mortality of seedlings. Since a recently-emerged seedling could not supply the physiological costs of specialized strategies, we expected the highest synchronous leaf production in the youngest individuals, and differences between cohorts in foliar damage. Four variables were measured to evaluate the health state along time, in three cohorts of seedlings: Proportion of predated leaves (Pp, proportion of healthy leaves (Ps, proportion of leaves with symptoms of disease or punctual damage (Pe and growing (% increment of height. Both species showed significant differences between periods in the proportion of healthy leaves, but there was not an effect of time-cohort interaction, therefore synchronic production of leaves was not a strategy more used for any particular cohort. Foliar damage oscillated along time, fact that can be explained by the pulses of leaf production. However, this strategy had little efficiency to control the pathogen attack. in general, the unified behavior of all variables was affected by cohort, time, species an all the different interactions. Association between growing and foliar damage were conditioned by climate. The highest mortality ocurred during the dry season, and one fourth of the D. granadensis deaths were caused by the joint action of herbivory and drought. Results suggest that in spite of the synchronous leaf production in all cohorts, this strategy quickly loses the efficiency for controlling foliar damage, because the means of Ps were below of 0.25 at the end of the monitoring period. The differences between species in the dynamics of health state should explain partially their coexistence in the High-Andean forest. Rev. Biol. Trop. 56 (3: 1087-1100. Epub 2008 September 30.

  2. Análisis florístico y fitogeográfico de un bosque secundario pluvial andino, cañón del río Santo Domingo, cordillera Central (Antioquia, Colombia

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    Diego Giraldo Cañas

    2001-01-01

    Full Text Available A detailed floristic inventory as well as a preliminary phytogeographical analysis was conducted in an Andean secondary wet forest of NW of Colombia, in order to know the vascular species richness and the phytogeographical relationships. The floristic inventory revealed the presence of 712 vascular species distributed among 129 families, of which 17 belong to ferns and allies, with 69 species and 30 genera; 18 monocotyledon families, with 153 species and 87 genera, and 94 dicotyledon families, with 490 species and 290 genera. The best-represented plant families are Melastomataceae (36 species, Rubiaceae (36, Orchidaceae (30, Asteraceae (28, Poaceae (28, Piperaceae (24, Araceae (23, Fabaceae (20, Clusiaceae (18, Moraceae (18, Gesneriaceae (17, Mimosaceae (16, Solanaceae (15, Acanthaceae (14, and Polypodiaceae (13. The richest genera are Piper (17 species, Ficus (11, Psychotria (11, Inga (10, Anthurium (9, Miconia (9, Peperomia (7, Asplenium (6, Blechnum (6, Clidemia (6, Costus (6, Mikania (6, Selaginella (6, and Solanum (6. Regarding life forms, herbs are the best represented with 344 species (48,2%, followed by shrubs and trees (291 species, 41%, lianas (62 species, 8,7%, palms (12 species, 1,7% and by arborescent herbs (3 species, 0,4%. There are 101 epiphytic or hemiepiphytic species belonging to 23 families. The richest families in epiphytes are Orchidaceae (23 species, Araceae (10, Bromeliaceae (8, Piperaceae (7 and Gesneriaceae (6, while the most common epiphytic genera are Peperomia (7 species, Anthurium (6, Elaphoglossum (5, Huperzia (4 and Trichomanes (4. There are 9 endemic species (1,3%. Some of the species collected are new to science or are new records for the flora of NW of South America. Nine species and 3 genera exhibit a disjunct distribution. The analyzed forest is floristically similar to lowland Neotropical forests. The phytogeographic analysis shows that 62,4% of the genera are neotropical, 25,8% are pantropical, 10% are cosmopolitan, 1,8% are holarctic, and that 15 genera have a tropical amphipacific distribution. Nine genera are confined to South America. Although the area studied was strongly modified, only 8 species are introduced or naturalized. The frequency of disturbances, such as fire, grazing, cutting, selective cutting, abandoned cultivat fields, maintains the area at early successional stages

  3. ESTATUS DE LA POBLACIÓN DE MONOS AULLADORES ROJOS EN EL CAÑÓN DEL BARBAS, FRAGMENTO MONTANO, CORDILLERA CENTRAL, Colombia Status of the red howler monkeys population in the Barbas canion, montane fragment, central mountains, Colombia

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    Jorge Mario Londoño

    Full Text Available Los bosques de montaña en Colombia han sufrido fuerte degradación por causas antrópicas y en la actualidad la mayoría son remanentes aislados e inmersos en hábitat antropogénicos. Los aulladores rojos han persistido en estas condiciones pero poco se conoce sobre su biología y respuesta a la alteración de su ambiente. Durante cinco meses en el 2005, evaluamos densidad y estatus poblacional de esta especie en la cuenca del río Barbas (Departamentos de Quindío y Risaralda, fragmento aislado de bosque montano bajo de 790 ha . Estimamos la densidad empleando censos por transectos lineales repetidos. Adicionalmente seguimos tropas de aulladores y evaluamos variables de vegetación teniendo en cuenta los requerimientos ecológicos de la especie. Estimamos una densidad de 11.7±6 grupos y 132.1±68 individuos/km2, superior a la usualmente reportada en bosques continuos. Esta alta densidad probablemente se deba al aislamiento del fragmento, que limita las posibilidades de dispersión de los aulladores. El tamaño promedio por tropa fue 11.3±2.5 individuos, con más de cinco machos y siete hembras adultas, y de uno a cuatro inmaduros. En general el bosque ofrece buena disponibilidad de recursos estructurales y alimenticios para los aulladores. Esta población no se encuentra amenazada en la actualidad por actividades antrópicas. El fragmento ha sido recientemente protegido bajo la figura de Parque Regional Natural y se adelantan corredores de conexión con otros remanentes cercanos. Sin embargo, esta población de aulladores se encuentra aislada de otras poblaciones y por tanto es urgente desarrollar medidas de manejo del paisaje para atenuar los efectos del aislamiento.The montane forests in Colombia have suffered strong degradation due to human activities; currently, most of them are remnants isolated and immersed in anthropogenic habitats. The red howler monkeys have persisted in these conditions but little is known on their biology and response to the alteration of their environment. During five months in 2005, we evaluated the population density and status of this species in the basin of the Barbas River (Quindío and Risaralda departments, a low montane isolated forest fragment of 790 ha . We estimated density by censuses for linear repeated transects. Additionally we followed troops of howlers and evaluated vegetation variables according to howler ecological requirements. We estimated a density of 11.7±6 groups and 132.1±68 individuals per km2, higher than what is usually reported for this species in continuous forests. This high density might be caused due to the isolation of the fragment that reduces the possibilities of dispersion of the howlers. The average troop size was 11±2.5 individuals, with more than five males and seven females, and one to four immature individuals. In general, the forest offers to the howlers, good availability of food and structural resources. Currently, this population is not threatened by anthropogenic activities. Recently, this fragment has been protected as a Regional Park , and it exists a project to develop corridors of connection with others remnants. Nevertheless, this howler population is isolated of other populations, and therefore urgent measures of landscape management are needed to attenuate the effects of the isolation.

  4. Estudio de ecosistemas acuáticos y terrestres en el PNN el Cocuy. componentes de vegetación y limnología. cordillera oriental sector occidental

    OpenAIRE

    Barbero García, María Paula; Castiblanco Álvarez, Felipe; Díaz Corredor, Sergio Alejandro; Duarte Rojas, Daniel José; Fierro Rojas, Lina Marcela; Fontanilla Ramírez, Paula Victoria; Holguín Villarreal, Laura Elizabeth; Márquez Niño, Fabián Giovanny; Molano González, Nicolás; Morales Álvarez, Anamaría; Morantes Ariza, Carlos Fabián; Moreno Barragán, Fredy Fabiany; Ontiveros Ospina, María Katherine; Paternina Cruz, Ricardo Felipe; Pinto Gómez, Alejandro

    2011-01-01

    Dentro de la asignatura "Ecología Regional Continental" (Departamento de Biología, Universidad Nacional de Colombia), se realizó una visita de campo al Parque Nacional Natural El Cocuy-PNN-EC (Boyacá), en septiembre de 2011. Se hicieron estudios de ambientes terrestres y acuáticos desde la perspectiva de biomas, paisajes y ecosistemas. Los ecosistemas terrestres y acuáticos del PNN-EC presentan como tendencia general condiciones favorables en los biomas más superiores de superpáramo y páramo,...

  5. Estudios ecológicos en la Cordillera Oriental IV: Aspectos sinecológicos de la brioflora de los depósitos turbosos paramunos de los alrededores de Bogotá Estudios ecológicos en la Cordillera Oriental IV: Aspectos sinecológicos de la brioflora de los depósitos turbosos paramunos de los alrededores de Bogotá

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    Sánchez M. Roberto

    1989-09-01

    Full Text Available Mediante los lineamientos metodológicos de la escuela Zurich-Montpellier (Braun-Blanquet, 1979 se realizaron 102 levantamientos de la vegetación que se establece en los pantanos, turberas o depósitos turbosos de los páramos de los alrededores de Bogotá. En la caracterización de esta vegetación, los musgos y las hepáticas desempeñan un papel importante; varias especies de Sphagnum son dominantes en diferentes fases del proceso de sucesión sobre esos ambientes originados de cubetas y lagunas glaciares. EI sustrato es muy variable en su constitución y en las características físico-químicas; en general, prevalece un contenido alto de materia orgánica, aceptable cantidad de nitrógeno y valores reducidos de elementos como magnesio, calcio y potasio. En esta contribución se presenta una reseña a nivel regional de las características primordiales de los sitios investigados en cuanto al papel desempeñado por las especies de briófitas en la composición florística, y a las condiciones físico-químicas del sustrato. The vegetation established on" peat deposits "or marshes in the paramos around Bogota is treated following the Zurich-Montpellier system. 102 releves of vegetation were realized. Mosses and liverVllorths play an important role in the structure and floristic composition of this vegetation.  Several Sphagnum species are dominant in some steps of the sucession process from open water and small lake to marsh. The constitution of the substrate and its physical and chemical characteristics vary in the places investigated, but in general terms there is a high content of organic matter, fair content of nitrogen and low content of magnesium, calcium and potassium.  

  6. Emergy evaluation of benthic ecosystems influenced by upwelling in northern Chile: Contributions of the ecosystems to the regional economy

    Science.gov (United States)

    Emergy evaluations of three benthic ecosystem networks found in Mejillones, Antofagasta and Tongoy Bays, located on the coast of northern Chile, were carried out with the intent of documenting the contributions of these coastal ecosystems to the economy. The productivity of these...

  7. Records and reputations : everyday politics of a Philippine Development NGO

    NARCIS (Netherlands)

    Hilhorst, D.

    2000-01-01

    This study looks into the working of policies, practices and accountability of NGOs. It is based on fieldwork with one development NGO in the Cordillera of the Philippines: the Cordillera Women NGO, or CWNGO (a pseudonym). Through this study I wanted to find out why certain groups of actors

  8. Una nueve especie del género Killipia (Melastomatacea

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    Ruiz Rodgers Natalia

    1997-06-01

    Full Text Available A new species of the genus Killipia (Melastomataceae from the "Serranía de los Paraguas" in the Cordillera Occidental of Colombia, is described and illustrated.Se describe e ilustra una nueva especie del género Killipia (Melastomataceae, de la Serranía de los Paraguas en la Cordillera Occidental de Colombia.

  9. Modelización genética de nódulos silíceos: aplicación al Devónico de Tabuenca (Cordillera Ibérica, España. I: Caracterización morfológica y composicional

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    Bona Artazos, M. E.

    2005-04-01

    Full Text Available Siliceous nodules of the Devonian deposits in the «Hoya Formation» (Tabuenca-Zaragoza have been studied. The nodules are included in lutites, and contain quartz, opaque minerals and clays. The cement is criptocrystalline quartz. Our morphologic study reveals that these are spheres and spheroids, with a gray colour and 0.3 to 9.6 cm of diameter, and grade into the direction of stratification. This spherical morphology is the result of isotropic structure of host sediment, and it indicates a growth mechanism by diffusion and a short transport mechanism. The existence of distorted lamination indicate that its central section was cemented before its outer section, and that its growth was passive, by a mechanism of porosity-grouth filling.Se han caracterizado morfológica y composicionalmente los nódulos silíceos que aparecen en los materiales pelíticos de la Formación Hoya (Devónico superior, en las proximidades de la localidad zaragozana de Tabuenca. Los nódulos se localizan entre capas de lutitas, y están compuestos por cuarzo criptocristalino, minerales arcillosos (caolinita principalmente, minerales opacos y restos fósiles. El estudio morfológico llevado a cabo revela que estas estructuras son esferas y esferoides, de color gris y con diámetro variable entre 0,3 y 9,6 cm. Además es destacable que se presentan con la misma orientación que la estratificación. Su morfología se explica producida por la estructura isótropa del sedimento hospedante, y ello indica que estas estructuras crecieron mediante un mecanismo de difusión y un transporte relativamente corto. La existencia de una laminación deformada alrededor de ellos mostraría que su parte central fue cementada, antes que la parte exterior, de manera pasiva mediante un mecanismo de crecimiento por relleno de porosidad.

  10. Some colored travertines from the Betic Range (SE Iberian Peninsula): their geological setting and petrophysical properties; Travertinos coloreados en la Cordillera Bética (SE de la Península Ibérica). Situación geológica y características petrofísicas

    Energy Technology Data Exchange (ETDEWEB)

    García-del-Cura, M.A.; Benavente, D.; Martínez-Martínez, J.; Ordóñez, S.

    2017-09-01

    The Betic Range contains several colored travertine deposits which were formed during the last stage of the post-tectonic Tertiary-Quaternary (Pleistocene) basin refill. Associated with active faults, these travertines are quarried in Alhama de Almería, Albox (Almería) and Baños de Mula (Murcia) for subsequent use as ornamental stone. The aim of this study was to characterize their facies and physical properties in order to establish their suitability for use as an ornamental stone. The main facies was banded (1-10 cm), and the travertines presented variable porosity ranging from 5- 15%. Porosity is related to travertine texture: a) fairly homogeneous microporosity, with a mode between 0.005 and 0.05 µm, is linked to micritic carbonate; and b) a porosity mode varying widely from 0.05 to 2 µm is associated with larger crystals. A characteristic feature of these travertine deposits was their macroporosity of variable size and distribution. The coefficient of capillary absorption was highly anisotropic and presented very different magnitudes in the different travertines studied. A minimum value of 1.42 (g/m2 s0.5) was observed in the commercial Red Alhama travertine, in an oblique direction to the structure, while the maximum value of 10.71 (g/m2 s0.5) was found in Albox travertine deposits, in a parallel direction to the structure. Strength was markedly anisotropic, attaining compressive strength values as high as 68 MPa in the direction perpendicular to the bedding planes. When cut in this direction, the travertines studied yield good quality ornamental stone within the category of commercial marble. [Spanish] En la zona Bética Externa, se encuentran depósitos de travertinos coloreados de valor como rocas ornamentales cuyas características petrofísicas son poco conocidas. Están en relación con fallas activas. Las canteras de travertino se sitúan en Alhama de Almería, Albox (Almería) y Baños de Mula (Murcia). Estos travertinos forman parte de la última etapa del relleno de las cuencas terciarias postectónicas béticas (Pleistoceno) y generalmente aparecen espacialmente asociados a episodios tobáceos. El objetivo de este trabajo es definir las facies de estos travertinos y las características petrofísicas que presentan con vistas a su utilización como roca ornamental. Predominan en ellos las facies bandeadas (1 - 10 cm). Su porosidad es variable (5 - 15%) consistente en una microporosidad bastante homogénea, con moda (0.005-0.05 µm) ligada al carbonato micrítico, y una familia de poros menos seleccionada entre 0.05-2 µm asociada a cristales de mayor tamaño. La macroporosidad de tamaño y disposición variable es un rasgo característico de estos travertinos. El coeficiente de absorción capilar es muy anisótropo y varía mucho en los diferentes travertinos estudiados. El valor mínimo encontrado en travertinos comercializados ha sido de 1.42 (g/m2 s0.5) en dirección oblicua a la estructura en el travertino Rojo Alhama y el máximo de 10.71(g/m2 s0.5) en dirección paralela a la estructura en el travertino de Albox. Su resistencia es notablemente anisótropa, encontrando valores de resistencia a compresión que pueden llegar a alcanzar 68 MPa en dirección perpendicular al bandeado. Cortados en dicha dirección constituyen una roca ornamental de buena calidad dentro de la categoría de mármoles comerciales.

  11. Lixiviación de concentrados de cobre utilizando NaCI y el cobre soluble aportado por el propio concentrado

    OpenAIRE

    Herreros, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Viñals, J.

    2005-01-01

    Leaching of copper concentrates using cupric chlorocomplexes, generated "in situ" by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variables such as chloride concentration, soluble copper concentration, leaching time, solid pe...

  12. Rapid reduction in breast cancer mortality with inorganic arsenic in drinking water

    OpenAIRE

    Smith, Allan H; Marshall, Guillermo; Yuan, Yan; Steinmaus, Craig; Liaw, Jane; Smith, Martyn T.; Wood, Lily; Heirich, Marissa; Fritzemeier, Rebecca M.; Pegram, Mark D; Ferreccio, Catterina

    2014-01-01

    Background: Arsenic trioxide is effective in treating promyelocytic leukemia, and laboratory studies demonstrate that arsenic trioxide causes apoptosis of human breast cancer cells. Region II in northern Chile experienced very high concentrations of inorganic arsenic in drinking water, especially in the main city Antofagasta from 1958 until an arsenic removal plant was installed in 1970. Methods: We investigated breast cancer mortality from 1950 to 2010 among women in Region II compared to...

  13. Morbid condition involving cardio-vascular, broncho-pulmonary, digestive and neural lesions in children and young adults after dietary arsenic exposure

    Energy Technology Data Exchange (ETDEWEB)

    Zaldivar, R.

    1980-02-01

    An investigation on the relationship between dietary arsenic exposure and cardiovascular diseases was made. In Antofagasta Commune, northern Chile, since 1955 arsenic has polluted public drinking water. This environmental contamination is of geological origin. The concentration of arsenic in drinking water for the 1955 to 1970 period was 0.5980 ppM. In the period June 1970 to March 1972, the concentration decreased to 0.0815 ppM due to a water filtration plant which started operating in May 1970. Greater Santiago showed 0.00 ppM of arsenic in drinking water. Amongst 10 autopsied patients with chronic arsenical dermatosis from Antofagasta Commune, 9 showed marked fibrous intimal thickening of the arterial wall and/or restricted lumen of the left coronary artery, 2 of these 9 also exhibiting myocardial infarction. Of the 10 patients, 7 developed cardiomegaly, which was related to chronic exposure to dietary arsenic. Two series of patients with myocardial infarction under 40 years of age, one from Antofagasta Commune, the other from greater Santiago (not exposed to arsenic) were compared. The Yates corrected chi 2 value being 11.7776. The difference was statistically highly significant. In Antofagasta Commune, the number of cases which had myocardial infarction with chronic arsenical dermatosis were compared with the cases which showed, myocardial infarction without chronic arsenical dermatosis. The Yates corrected chi 2 value was 13.0395. A highly significant difference was detected. Children from the two cities were also compared. The number of cases with myocardial infarction showed a significant difference; Fisher's exact test yielded a P approximately equal to 0.004944, the Yates corrected chi 2 value being 20.7311. The number of children with systemic occlusive arterial disease from the two cities also exhibited a highly significant difference.

  14. From the batholith to a monument: Machu Picchu

    OpenAIRE

    Mendoza Delgadillo, J.

    2016-01-01

    La ciudad inca Machu Picchu fue construida, sobre el batolito que lleva el mismo nombre, en plena cordillera de Vilcabamba, nominación regional que toma la cordillera oriental de los Andes del sur del Perú. La cordillera de Vilcabamba está constituida por rocas del Paleozoico y Cenozoico y por batolitos hercínicos y permo-triásicos cuyos plutones intruyen rocas paleozoicas. Machu Picchu se encuentra en un área periglacial, consta de dos partes bien definidas: una urbana y otra agrícola. La pa...

  15. The M 7.7 Tocopilla earthquake and its aftershock sequence: deployment of a Task Force local network

    Science.gov (United States)

    Sobiesiak, M.; Eggert, S.; Woith, H.; Grosser, H.; Peyrat, S.; Vilotte, J.; Medina, E.; Ruch, J.; Walter, T.; Victor, P.; Barrientos, S.; Gonzalez, G.

    2008-05-01

    After the November 14, 2007 Tocopilla earthquake in northern Chile, a local network of 20 short period seismic stations, 5 strong motion instruments, 6 GPS stations and 3 extensometers has been installed in the fault plane area between Tocopilla and Antofagasta by the German Task Force for earthquakes (GFZ Potsdam). The hydrogeology group of the TF sampled 20 thermal water sources in the area of the El Tatio geyser field, located about 170 km E of the epicentre. In collaboration with the IPG Paris, 4 broad band stations were deployed at the northern end of the fault plane between Tocopilla and Maria Elena. Major targets of the investigations of the aftershock sequence are the segment boundary between the 1995 Antofagasta earthquake and the recent Tocopilla event, stress transfer between both successively ruptured subduction zone segments, structural properties of the fault plane, possible consequences for the northern adjacent Iquique segment, and the influence of earthquake seismic waves on the El Tatio hydrothermal field. In our presentation we would like to show first results on the spatial distribution of the aftershocks and discuss these in relation to studies we have made on the Antofagasta aftershock sequence.

  16. Modelacion del crecimiento de Albizia niopoides por metodos dendrocronologicos

    National Research Council Canada - National Science Library

    Giraldo, Victor David; del Valle, Jorge Ignacio

    2012-01-01

    El crecimiento anual de los anillos en los arboles de los bosques tropicales es bastante frecuente y se evidencio en los arboles de Albizia niopoides, que crecen en el canon del rio Porce, cordillera...

  17. Multi‐scale topographic control of southwest vortex formation in Tibetan Plateau region in an idealized simulation

    National Research Council Canada - National Science Library

    Wang, Qi‐Wei; Tan, Zhe‐Min

    2014-01-01

    The southwest vortex (SWV) is a lee vortex occurring on the leeside of the Tibetan Plateau in southwestern China, which is strongly affected by the different scale topography of the Tibetan Plateau, Hengduan Cordillera, and Sichuan Basin...

  18. Evolution of ice-dammed proglacial lakes in Última Esperanza, Chile: implications from the late-glacial R1 eruption of Reclús volcano, Andean Austral Volcanic Zone Evolución de lagos proglaciales embalsados por hielo en Última Esperanza, Chile: Implicancias de la explosión volcánica tardiglacial R1 del volcán Reclús, Zona Volcánica Austral Andina

    National Research Council Canada - National Science Library

    Charles R Stern; Patricio I Moreno; Rodrigo Villa-Martínez; Esteban A Sagredo; Alfredo Prieto; Rafael Labarca

    2011-01-01

    .... The geographic and stratigraphic distribution of Rl also place constraints on the evolution of the ice-dammed proglacial lake that existed east of the cordillera in this area between the termination...

  19. Aeromagnetic and Bouger Gravity Data from Bolivia

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — As part of a two-year assessment of the geology and mineral resources of the Altiplano and Cordillera Occidental, Bolivia, aeromagnetic and gravity data were...

  20. Influencia de un bloque rígido en un sistema de fallas de rumbo: modelamiento análogo Influence of a rigid block in a strike-slip fault system: analogue modelling

    Directory of Open Access Journals (Sweden)

    Thierry Nalpas

    2011-01-01

    Full Text Available En este trabajo se presenta un estudio de modelamiento análogo sobre la naturaleza, geometría y cinemática de la deformación a lo largo de fallas de rumbo dada la presencia de un bloque rígido en su trayectoria de deformación. Los modelos análogos están apropiadamente escalados considerando las características reológicas de los materiales que se desean contrastar en la deformación. Dos grandes parámetros fueron probados: la configuración del bloque rígido, variando su forma y tamaño, y el monto del desplazamiento. Los resultados experimentales muestran el desarrollo de rotaciones, fallas y pliegues como producto de la presencia de un bloque rígido en la trayectoria de falla. Los diversos casos geométricos probados pueden ser empleados para su comparación con sistemas de fallas de rumbo en los cuales existen diferencias litológicas de comportamiento reológico diferencial, como por ejemplo el caso del 'Núcleo rígido de Limón Verde' al sur de Chuquicamata, ubicado en la trayectoria del sistema de fallas de Domeyko.This work addresses the kinematic effects of a rigid block in strike-slip systems by using analogue models. The experiments (size, behaviour of materials were scaled down in order to represent deformation of the tested rheologic contrast conditions in deformation. Two main parameters were tested: the configuration of the rigid block, changing its form and size, and the amount of displacement. The experiments evidenced the development of rotations, faults and folds along the fault trajectory, as resulting from the presence of the rigid block during the deformation. Testing of diverse geometric situations may be used for comparison to strike-slip fault systems in which different lithologies and rheologic behaviour exist, for example, presence of the 'Limón Verde rigid core' along the Domeyko fault system, just south of Chuquicamata.

  1. El valor científico de una colección mineralógica en la reconstitución de tres antiguos distritos argentíferos: Arqueros, Algodones y Rodaito (Norte de Chile

    Directory of Open Access Journals (Sweden)

    Oyarzun, J.

    1991-08-01

    Full Text Available Arqueros, Algodones and Rodaíto are silver districts from northern Chile that were of major economic importance during the XIX century. Since the deposits were extensively mined during the last century, at present, the main mineralogical record is kept at the «Colección Ignacio Domeyko», a major collection belonging to the Mineralogical Museum of La Serena (Chile. The study of the collection together with a revision of the local geology of the districts led to the following conclusions: 1 the districts are formed by Comstock/Creede-type epithermal silver-base metals deposits, which are hosted by volcanic and sedimentary rocks of Cretaceous age: 2 the studied parageneses can be ascribed to the Cu-Pb-Zn-Ag association (e.g. Creede, Colorado, USA; Zacatecas, Mexico; 3 the presence of skutterudite and erythrite suggests, however, a transitional character towards other mineralogical associations: Ag-Bi-Co-Ni-As (e.g. Cobalt, Ontario, Canada and Pb-Zn-Ag (Sb-As (Coeur d'Alene, Idaho, USA.Arqueros, Algodones y Rodaíto son tres distritos argentíferos del norte de Chile que tuvieron gran importancia económica en el siglo XIX. Dado que fueron intensamente explotados en el siglo pasado, en la actualidad el principal testimonio mineralógico lo constituye la Colección Mineralógica Ignacio Domeyko del Museo Mineralógico de La Serena (Chile. El estudio de esta colección, junto con la revisión de la geología distrital de estos yacimientos, permite establecer las siguientes conclusiones: 1 los tres distritos son mineralizaciones filonianas epitermales encajadas en rocas volcánicas y sedimentarias del Cretácico, y son asignables a los modelos de yacimientos argentíferos tipo «Comstock» o «Creede»; 2 las paragénesis estudiadas pueden asimilarse a la asociación Cu-Pb-Zn-Ag (e.g. Creede, Colorado, USA; Zacatecas, México; 3 la existencia de skutterudita y eritrina sugiere, sin embargo, un cierto carácter transicional respecto a

  2. Dos nuevos registros de ascidias (Tunicata: Ascidiacea para la costa continental de Chile Two new records of ascidians (Tunicata: Ascidiacea for the continental coast of Chile

    Directory of Open Access Journals (Sweden)

    MARCELA CLARKE

    2000-09-01

    Full Text Available Las ascidias (Tunicata: Ascidiacea Asterocarpa humilis (Heller, 1878 (Styelidae y Molgula ficus (Macdonald, 1859 (Molgulidae se registran por primera vez, para la costa de Chile continental. Los ejemplares se recolectaron en los años 1997 y 1998 en tres localidades en los alrededores de la Bahía de Antofagasta, Chile (23º43´S; 70º 26´W, asociados a las agrupaciones de las ascidias Pyura chilensis Molina, 1872 y Ciona intestinalis Linnaeus, 1767, que se fijan en sistemas suspendidos de cultivo de ostiones y en mantos intermareales del «piure de Antofagasta», P. praeputialis (Heller, 1878. En el trabajo se describen las especies y se discuten sus distribuciones geográficas y la posibilidad que ambas hayan sido introducidas o invadido costas de Chile. Se destaca el carácter vivíparo para A. humilis. Con este trabajo el número de especies de ascidias descritas para Chile continental se eleva desde 53 a 55The ascidians (Tunicata: Ascidiacea Asterocarpa humilis (Heller, 1878 (Styelidae and Molgula ficus (Macdonald, 1859 (Molgulidae are recorded for the first time for the continental coast of Chile. The specimens were collected during 1997 and 1998 at 3 localities in and around the Bay of Antofagasta (23º 43´ S; 70º 26´ W, Chile, in suspended scallop aquaculture ropes, attached to Ciona intestinalis Linnaeus, 1767 and Pyura chilensis Molina, 1872, and in intertidal beds of the sea squirt P. praeputialis (Heller, 1878. This work describes the species and discusses their geographical distribution as well as possibilities for their introduction and/or invasion to Chile. The viviparous condition for A. humilis is communicated. The number of ascidians reported for continental Chile increases from 53 to 55

  3. Lixiviacion de concentrados de cobre utilizando NaCl y el cobre soluble aportado por el propio concentrado.

    OpenAIRE

    Herreros, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Viñals Olia, Juan

    2005-01-01

    Se ha estudiado la lixiviación de concentrados de cobre mediante cloro-complejos cúpricos, generados in situ por la reacción entre el Cu(II) procedente del cobre soluble del concentrado y cloruro de sodio en medio ácido. Se utilizaron concentrados de cobre provenientes de faenas mineras de Antofagasta, Chile. Se ha efectuado una caracterización química y mineralógica de los concentrados originales. Se ha estudiado el efecto de las siguientes variables, durante la lixiviación: concentración de...

  4. Medication nonadherence among South American patients with schizophrenia

    OpenAIRE

    Caqueo-Urízar,Alejandra; Urzúa,Alfonso; Fond, Guillaume; Boyer, Laurent

    2017-01-01

    Alejandra Caqueo-Urízar,1 Alfonso Urzúa,2 Guillaume Fond,3,4 Laurent Boyer5 1Universidad de Tarapacá, Escuela de Psicología y Filosofía, Arica, Chile; 2Universidad Católica del Norte, Avda, Angamos, Antofagasta, Chile; 3Université Paris Est-Créteil, Pôle de Psychiatrie des Hôpitaux Universitaires H Mondor, INSERM U955, Eq Psychiatrie Translationnelle, DHU Pe-Psy, France; 4Fondation Fon...

  5. ARSENICO EN EL CAMPO GEOTERMICO DE EL TATIO: ESPECIACION EN SINTERES Y COMUNIDADES MICROBIANAS

    OpenAIRE

    ALSINA CORVALAN, MARCO ANTONIO

    2013-01-01

    El arsénico es ubicuo en las aguas de diversos campos geotérmicos, aunque poco se conoce acerca de su especiación química en las fases solidas asociadas a las descargas hidrotermales, y por ende su biodisponibilidad frente a cambios en las condiciones geoquímicas derivadas de actividades antropogénicas o naturales. Este trabajo evalúa la presencia de arsénico en sinterita silícea y alfombras microbianas de un canal hidrotermal del Campo Geotérmico El Tatio (Región de Antofagasta, Chile) de...

  6. GABRIELA MISTRAL, VIOLETA PARRA, CECILIA VICUÑA Y SOLEDAD FARIÑA: POETICAS DE LAS ARTES INTEGRADAS

    OpenAIRE

    ARIZ CASTILLO, YENNY KAREN

    2013-01-01

    La presente investigación aborda un corpus específico de textos de Gabriela Mistral (Vicuña, 1889 - Nueva York, 1957), Violeta Parra (San Carlos, 1917 - Santiago, 1967), Soledad Fariña (Antofagasta, 1943) y Cecilia Vicuña (Santiago, 1948): Poema de Chile (1967), Décimas. Autobiografía en verso (1970), La vocal de la tierra (1999), y La Wik’uña (1990), respectivamente, en función de una hipótesis que sostiene la presencia de una poética1 de “arte global” o “artes integradas” en ...

  7. Transformación de los liderazgos en la minería: gestión estratégica para incorporar mujeres a la industria

    OpenAIRE

    Paulina Irene Salinas Meruane; Camila Fernanda Cordero Chau

    2016-01-01

    La menor participación de las mujeres en la industria minera predomina a nivel internacional. En Chile, a pesar de las mayores remuneraciones, del nivel tecnológico y del déficit proyectado de capital humano en el sector, las mujeres representan el 4,2% en las áreas operacionales. El objetivo de este trabajo es analizar el rol de las jefaturas mineras para revertir esta condición. Con un estudio de caso, en la Compañía Minera Esperanza perteneciente al grupo Antofagasta Minerals, ubicad...

  8. Sitio arqueológico "Las Fundiciones". : Sitios de importancia metalúrgica en el Desierto de Atacama.

    OpenAIRE

    Salazar, Diego; Guendon, Jean-Louis; Figueroa Larre, Valentina; Salinas, Hernán; Winkler, Lisette; Borie, Cesar

    2007-01-01

    Corpus PCM (Peuples et Cultures du Monde); El sitio arqueológico « Las Fundiciones » se ubica en el Rio San Salvador, en la segunda región de Antofagasta, norte de Chile. El equipo de arqueólogos llegó a éste lugar, atraídos por descripciones y evidencias superfic iales que indicaban que se trataba de un área de importancia metalúrgica asociada a los períodos intermedio tardio y tardío de la prehistoria regional. Parte del proyecto de colaboración (CNRS-CONICYT), implicaba una evaluación prel...

  9. Absceso perirrenal recidivante con atrofia renal izquierda: reporte de un caso

    OpenAIRE

    Nicolás Drolett SF.; Manuel Quiroz F.; Marcelo Zamorano D.

    2014-01-01

    INTRODUCCIÓN: El absceso perirrenal es una entidad infrecuente donde la presentación insidiosa y variable favorece el retraso del diagnóstico reportándose una mortalidad de 39-50%. Nuestro objetivo es presentar y analizar una paciente con absceso perirrenal que recidivó, con énfasis en el tratamiento y diagnóstico. PRESENTACIÓN DEL CASO: Mujer de 56 años consulta en Hospital Regional de Antofagasta por síntomas urinarios de un mes de evolución, reciente aparición de dolor en zona lumbar y fie...

  10. MATHEMATICAL MODELLING OF CALICHE HEAP LEACHING

    OpenAIRE

    Ordóñez Contreras, JAVIER IGNACIO

    2013-01-01

    El caliche es un mineral compuesto por una alta proporción de especies solubles en agua que se encuentra naturalmente presente en el norte de Chile, en las regiones de Tarapacá y Antofagasta. Los productos más importantes que se obtienen de este mineral son: nitratos y yodo. El nitrato es empleado para la fabricación de fertilizantes y el yodo en aplicaciones médicas y tecnológicas. Chile es el principal productor de yodo y nitratos naturales en el mundo. Para la producción ...

  11. Reestablecimiento de Choromytilus chorus (Molina, 1782 (Bivalvia: Mytilidae en el norte de Chile Reestablishment of Choromytilus chorus (Molina, 1782 (Bivalvia: Mytilidae in northern Chile

    Directory of Open Access Journals (Sweden)

    Miguel Avendaño

    2011-07-01

    Full Text Available Hasta fines del siglo pasado no existían registros de la presencia de Choromytilus chorus al norte de los 23°S, pese a antecedentes que señalaban su existencia en épocas pasadas. Ciertos cambios relacionados con las masas de agua costeras de esta zona, habrían generado la ausencia o escasez que presentaba el entorno costero actual. Sin embargo, hace una década atrás, su presencia en el norte de Chile, comienza a tener connotación pesquera. En el presente trabajo se confirma su reestablecimiento en las regiones de Antofagasta y Tarapacá, mediante prospecciones realizadas en seis lugares donde se registró su presencia, así como mediante la captación de semilla en colectores suspendidos. Se indica interacción con Aulacomya ater, a la cual ha desplazado a estratos más profundos, mientras que su reestablecimiento, iniciado en las regiones de Atacama y Antofagasta, y que se amplió posteriormente a la región de Tarapacá; permite postular la hipótesis que la dinámica de estos bancos, respondería a una estructura de metapoblación, dado el sistema de corrientes y vientos que predominan en la zona norte, permitiendo la advección larval de poblaciones existentes en la región de Coquimbo.Despite indications of its presence in past ages, until the end of the last century, no records showed Choromytilus chorus north of 23°S. Certain changes related to coastal water masses in the zone could be responsible for the present lack or scarcity of this species in the coastal area. However, a decade ago, this species appeared in northern Chile in the context of fisheries. This study confirms the re-establishment of C. chorus in the Antofagasta and Tarapaca regions through surveys at six sites where the species had been registered and spat collection using suspended collectors. This species has interacted with Aulacomya ater, displacing it towards deeper habitats. The re-establishment of C. chorus began in the Atacama and Antofagasta regions and

  12. Impact of lower plate structure on upper plate deformation at the NW Sumatran convergent margin from seafloor morphology

    Digital Repository Service at National Institute of Oceanography (India)

    Graindorge, D.; Klingelhoefer, F.; Sibuet, J-C.; McNeill, L.; Henstock, T.J.; Dean, S.; Gutscher, M-A.; Dessa, J.X.; Permana, H.; Singh, S.C.; Leau, H.; White, N.; Carton, H.; Malod, J.A.; Rangin, C.; Aryawan, K.G.; Chaubey, A.K.; Chauhan, A.; Galih, D.R.; Greenroyd, C.J.; Laesanpura, A.; Prihantono, J.; Royle, G.; Shankar, U.

    out at a mean speed of 14 knots. Positions were computed in the geodetic system WGS 84. Sound velocities were obtained using regularly spaced SIPPICAN Expendable Temperature probes (XBT's) and processed manually with CARAIBES software on board. The HMS...–AndamanearthquakefromGPSmeasurementsonsoutheastAsia.Nature436, 201–206. von Huene, R., Ranero, C.R., 2003. Subduction erosion and basal friction along the sediment-starved convergent margin off Antofagasta, Chile. J. Geophys. Res. 108 (B2), 2079. doi:10.1029/2001JB001569. Weinrebe, W., Ranero, C.R., Diaz, J...

  13. Evaluacion base para una eventual Área Marina Protegida (AMP) en el norte de Chile (III Región).

    OpenAIRE

    Vásquez, Julio

    2002-01-01

    En Chile, las áreas marinas protegidas (AMP) constituyen un herramienta de conservación creada recientemente a través de la Ley General de Pesca y Acuicultura. A lo largo de más de 4000 km de costa, sólo existe una AMP en el litoral de Chile continental, localizada en la costa de la II Región-Antofagasta. Esta AMP está orientada a la conservación y preservación de Argopecten purpuratus "Ostión del Norte".

  14. VIOLENCIA PSICOLÓGICA EN EL NOVIAZGO EN ESTUDIANTES UNIVERSITARIOS CHILENOS: DIFERENCIAS EN EL APEGO Y LA EMPATÍA DIÁDICA

    OpenAIRE

    Mónica Guzmán-González; Stephanie García; Bárbara Sandoval; Nicol Vásquez; Camila Villagrán

    2014-01-01

    El propósito del estudio fue evaluar diferencias en el apego romántico y la empatía diádica en función de la presencia/ausencia de violencia psicológica perpetrada en relaciones de noviazgo entre jóvenes universitarios. La muestra constó de 470 estudiantes entre los 18 y 28 años de la ciudad de Antofagasta, Chile, quienes completaron el cuestionario de Experiencias en Relaciones Cercanas (Brennan, Clark & Shaver, 1998), el Índice de Reactividad Interpersonal para Parejas (Péloquin & Lafontain...

  15. Landslides caused by the M 7.6 Tecomán, Mexico earthquake of January 21, 2003

    Science.gov (United States)

    Keefer, David K.; Wartman, Joseph; Navarro, Ochoa C.; Rodriguez-Marek, Adrian; Wieczorek, Gerald F.

    2006-01-01

    The Tecomán, Mexico earthquake (also called the “Colima earthquake”) of January 21, 2003 (M 7.6) triggered several hundreds of landslides in the coastal cordilleras of Colima State, near the earthquake source, and several thousands in the volcanic highlands north and northwest of Colima City. These landslides, mostly shallow and disrupted failures, caused minor damage to roads, to a railroad, and to irrigation systems. In one area, extensive, post-earthquake rock-fall activity indicates a possible long-term instability that could threaten dwellings and other infrastructure located nearby. In the coastal cordilleras, most of the landslides were generated by failures of artificially cut slopes, especially along roads. The rocks of the coastal cordilleras are generally well indurated, and landslides occurred only where the rocks were made locally susceptible by weathering, the presence of prominent discontinuities with unfavorable orientations, or intense fracturing or shearing.

  16. A new minute Andean Pristimantis (Anura: Strabomantidae from Venezuela

    Directory of Open Access Journals (Sweden)

    César L. Barrio-Amorós

    2012-12-01

    Full Text Available A new species of Pristimantis is described from the Venezuelan Andes. The new species is the smallest in its genus known in Venezuela and belongs to the Pristimantis unistrigatus Group. It differs from the rest of Venezuelan Andean congeners in body size (mean male SVL < 21.3 mm, female SVL < 26.3 mm, expanded discs on fingers and toes, absence of dorsolateral folds, and a distinctivecall consisting in 2–5 cricket-like short notes. The new species inhabits the southwestern part of the Cordillera de Mérida in Venezuela and the Venezuelan side of the Cordillera Oriental deColombia, and could be present on the Colombian portion of the cordillera as well.

  17. "The Bridge" from Earthscope to EarthsCAN to Maintain North American Geoscience Momentum

    Science.gov (United States)

    Boggs, K. J. E.; Hyndman, R. D.; Eaton, D. W. S.

    2016-12-01

    "The Bridge", of seismic instruments across the Yukon-western NWT from the USArray-Alaska extending from the Pacific Ocean to the Beaufort Sea, is a possible proof of concept for the new EarthsCAN research initiative. The proposal is to fill gaps between the USArray-Alaska seismic stations, the McKenzie Mtn Earthscope Project, seismic sites of the Geological Survey of Canada, the Yukon Geological Survey, the University of Ottawa and other industry/government consortia. Workshop results defined important northern Cordillera questions. The Yukon Stable Block (YSB) is underlain in part by the Paleoproterozoic Wernecke Supergroup (not exposed elsewhere in the Cordillera). Cretaceous-Tertiary structures are deflected around the YSB suggesting stronger internal crust in the YSB. New GPS observations (Alaska and NW Canada) indicate that as the Yakutat block is colliding with North America that the Elias block is rotating counterclockwise, and the Alaska panhandle rotating clockwise into North America. Seismic activity also extends 800 km from the plate boundary to current deformation in the Mackenzie and Richardson Mountains. A model to explain neotectonic deformation proposes a strong upper crust, decoupled from the underlying mantle due to elevated basal temperatures, which is pushed against the plate boundary and transmits stresses throughout the Cordillera. Resolving these questions requires high-resolution seismic velocity models of the crust and mantle, dense GPS velocity fields, as well as mapping active faults in the Mackenzie Mountains and across the Cordillera via Lidar images and paleoseismic trenching. The transition from the actively deforming northern Cordillera to the relatively aseismic northern Rockies across a lithospheric-scale transfer zone inherited from former passive margins, similar to the one bounding the YSB in the north, may be an important characteristic of modern Cordilleras that controls tectonic activity.

  18. The Balearic Islands in the Alpine Orogeny

    Energy Technology Data Exchange (ETDEWEB)

    Bourrouilh, R.

    2016-10-01

    The place of the Balearic Islands in the Alpine orogeny is examined using detailed sedimentology studies, stratigraphical studies from the Lower Devonian (Lochkovian) to modern times and a careful tectonic review of sedimentary formations from the Western Mediterranean. Despite being considered as the ultimate end of the north-eastern termination of the Betic Cordillera, the history of the Balearic archipelago seems to be closer to the tectonic opening of the Gulf of Valencia and to the Corsica-Sardinia rotation, and thus to the tectonic history of the Western Mediterranean Sea, than to the tectonics of the Betic Cordillera which appear as its symmetrical image with respect to this opening. (Author)

  19. Cryptic species diversity in marsupial frogs (Anura: Hemiphractidae: Gastrotheca) in the Andes of northern Peru.

    Science.gov (United States)

    Duellman, William E; Barley, Anthony J; Venegas, Pablo J

    2014-02-25

    Molecular phylogenetic analysis revealed the existence of two undescribed species of the hemiphractid genus Gastrotheca in the Andes in northern Peru. Both species are similar morphologically to Gastrotheca dysprosita and G. monticola, but they differ from these species and from one another in subtleties of coloration and minor variances in size and proportions. Gastrotheca aguaruna sp. nov. (6˚10'50"S, 77˚37'01"W, 2480 m) is from humid forested areas in the northern part of the Cordillera Central, whereas G. aratia sp. nov. (6˚14'00"S, 78˚51'24"W, 2560 m ) is known from the northern part of the Cordillera Occidental.

  20. Una nueva especie del grupo Drosophila annulimana (Diptera, Drosophilidae y un nuevo registro en las Provincias de Pichincha y Napo, Ecuador

    Directory of Open Access Journals (Sweden)

    María Beatriz Cabezas

    2013-12-01

    Full Text Available En estudios realizados en el bosque nublado Intillacta, provincia de Pichincha, Ecuador, y en la Cordillera de los Guacamayos, provincia de Napo, Ecuador, se encontró una nueva especie de Drosophila. En base a estudios de la morfología de la genitalia masculina, se propone que, Drosophila intillacta sp. nov. pertenece al grupo Drosophila annulimana. Así mismo, se reporta Drosophila tarsata Schiner, 1868, capturada en la Cordillera de los Guacamayos, como un nuevo registro para el país.

  1. BIODIVERSIDAD DE LA CUENCA DEL ORINOCO: II.ÁREAS PRIORITARIAS PARA LA CONSERVACIÓN Y USO SOSTENIBLE

    OpenAIRE

    Lasso, Carlos A.; Rial B., Anabel; Matallana, Clara L.; Ramírez, Wilson; Celsa Señaris, Josefa; Díaz-Pulido, Angélica; Corzo, Germán; Machado-Allison, Antonio

    2011-01-01

    El área definida de la cuenca binacional del Orinoco comprende 981.446 km2. Sus límites se han establecido al occidente por la división de aguas de la cordillera Oriental de Colombia, al oriente por su desembocadura en el Océano Atlántico, al norte por la divisoria de aguas de la vertiente sur de la cordillera de la Costa en Venezuela y al sur por la cuenca del río Guaviare. Se subdividió en las siguientes unidades de análisis: 1) Orinoquia Llanera, 2) Orinoquia Andina, 3) Altillanura Orinoqu...

  2. Exhumation history of the Northern Andes from the Cenozoic syn-tectonic sedimentary fill of the Middle Magdalena Valley Basin, Colombia

    Science.gov (United States)

    Moreno, C. J.; Caballero, V. M.; Horton, B. K.; Mora, A.

    2009-12-01

    The Central Cordillera and the Eastern Cordillera of the northern Andes form the western and eastern flanks of the Colombian Middle Magdalena Valley Basin, respectively. Previous estimates of the timing of onset of exhumation of the two cordilleras vary, and although some recent studies have been in agreement, more work is needed to develop a clear picture. The spatial and chronological distribution of deformation has direct implications for the shortening history of the greater South American Andean margin, as well as for improving predictions of the rapid, lateral facies changes associated with the varying nearby sediment sources. Field-based analyses of the basin fill using paleocurrent measurements of trough-cross-beds, clast imbrication and flute casts, not only provide new insights into the tectonic history, but directly complement recent detrital zircon U-Pb work completed in the MMVB. Between the lower and upper Paleocene strata, the paleocurrent direction shifts from northward to eastward, indicating that uplift of the Central Cordillera was underway by the mid-Paleocene and consistent with the shift from a cratonic to Central Cordilleran sediment source observed in the detrital zircon record. This paleocurrent shift occurs coevally with a shift from delta to fluvial facies. An eastward paleoflow in upper Eocene through lowest Oligocene strata indicate a continuing influence of the Central Cordillera. Paleocurrent directions in the lower Oligocene deposits are highly variable, and, beginning in the middle Oligocene strata, show a switch to a dominantly westward orientation that continues through the Neogene. As the orientation changes, deposits show an increase in energy from muddy, meandering river deposits, to coarser, braided channel facies. We attribute this switch, from eastward to westward paleocurrent orientations, to the onset of exhumation of the Eastern Cordillera. The results of a current, detailed sandstone petrographic study combined with

  3. The relationship between orogenesis, terrane accretion and the subduction of oceanic ridges in the Ecuadorian andes

    Science.gov (United States)

    Spikings, R.; Winkler, W.; Seward, D.; Hughes, R.; Handler, R.; Crowhurst, P.

    2003-04-01

    Oceanic hotspot activity, generating large oceanic igneous plateau provinces, plate rearrangements and the generation of new spreading centers since at least 90 Ma have formed large structural, thickness and density heterogeneities in the approaching and subducting oceanic crust offshore NW South America (SOAM). Various oceanic allochthonous terranes comprise western Ecuador and the relatively thick and buoyant Carnegie Ridge is being subducted. We present 40Ar/39Ar, fission track (FT) and (U-Th/He) data from i) the Eastern Cordillera and the Amotape Complex, which define the palaeo-continental margin, ii) the Western Cordillera, which is built upon allochthonous, oceanic crust and iii) a tectonic mélange at the ocean-continent suture. 40Ar/39Ar ages and FT data from exotic, Triassic blocks within the ocean-continent suture record elevated cooling rates of plateau basalts and the continental margin. 40Ar/39Ar ages and FT data from the palaeo-continental margin show that the entire contemporaneous continental margin was being cooled by rapid tectonic exhumation (combined with geochemical analyses, suggest that these periods of orogenesis were driven by stress imposed by the collision of terranes that originated at the Caribbean Plateau. Distinct periods of rapid cooling and exhumation of fault blocks in the W. Cordillera and the northern E. Cordillera occurred at ˜15 and ˜9 Ma. Cooling at ˜15 Ma was driven by the collision of the Carnegie Ridge with the trench at ˜15 Ma. The elevated, compressive stress field gave rise to a complex transcurrent system, resulting in uplift, exhumation and cooling in the northern E. Cordillera and extension in the southern E. Cordillera. Finally, FT and (U-Th)/He data record rapid cooling in the northern E. Cordillera and parts of the W. Cordillera at ˜6-5 Ma, suggesting that the middle Miocene transcurrent system was reactivated by thrust tectonics during the late Miocene, giving rise to the Interandean Valley, which split the

  4. Urban weather data and building models for the inclusion of the urban heat island effect in building performance simulation

    Directory of Open Access Journals (Sweden)

    M. Palme

    2017-10-01

    Full Text Available This data article presents files supporting calculation for urban heat island (UHI inclusion in building performance simulation (BPS. Methodology is used in the research article “From urban climate to energy consumption. Enhancing building performance simulation by including the urban heat island effect” (Palme et al., 2017 [1]. In this research, a Geographical Information System (GIS study is done in order to statistically represent the most important urban scenarios of four South-American cities (Guayaquil, Lima, Antofagasta and Valparaíso. Then, a Principal Component Analysis (PCA is done to obtain reference Urban Tissues Categories (UTC to be used in urban weather simulation. The urban weather files are generated by using the Urban Weather Generator (UWG software (version 4.1 beta. Finally, BPS is run out with the Transient System Simulation (TRNSYS software (version 17. In this data paper, four sets of data are presented: 1 PCA data (excel to explain how to group different urban samples in representative UTC; 2 UWG data (text to reproduce the Urban Weather Generation for the UTC used in the four cities (4 UTC in Lima, Guayaquil, Antofagasta and 5 UTC in Valparaíso; 3 weather data (text with the resulting rural and urban weather; 4 BPS models (text data containing the TRNSYS models (four building models.

  5. Urban weather data and building models for the inclusion of the urban heat island effect in building performance simulation.

    Science.gov (United States)

    Palme, M; Inostroza, L; Villacreses, G; Lobato, A; Carrasco, C

    2017-10-01

    This data article presents files supporting calculation for urban heat island (UHI) inclusion in building performance simulation (BPS). Methodology is used in the research article "From urban climate to energy consumption. Enhancing building performance simulation by including the urban heat island effect" (Palme et al., 2017) [1]. In this research, a Geographical Information System (GIS) study is done in order to statistically represent the most important urban scenarios of four South-American cities (Guayaquil, Lima, Antofagasta and Valparaíso). Then, a Principal Component Analysis (PCA) is done to obtain reference Urban Tissues Categories (UTC) to be used in urban weather simulation. The urban weather files are generated by using the Urban Weather Generator (UWG) software (version 4.1 beta). Finally, BPS is run out with the Transient System Simulation (TRNSYS) software (version 17). In this data paper, four sets of data are presented: 1) PCA data (excel) to explain how to group different urban samples in representative UTC; 2) UWG data (text) to reproduce the Urban Weather Generation for the UTC used in the four cities (4 UTC in Lima, Guayaquil, Antofagasta and 5 UTC in Valparaíso); 3) weather data (text) with the resulting rural and urban weather; 4) BPS models (text) data containing the TRNSYS models (four building models).

  6. Escalas de producción en economías mineras: El caso de Chile en su dimensión regional

    Directory of Open Access Journals (Sweden)

    Nathaly Rivera

    2014-09-01

    Full Text Available Una proporción importante de la producción de cobre en Chile está geográficamente concentrada en dos regiones: Antofagasta y Atacama. A pesar de la evolución positiva del precio del cobre, el ingreso promedio de estas localidades ha presentado variaciones. Así, durante periodos de incrementos en el precio del cobre el ingreso promedio de Atacama ha aumentado, mientras que lo mismo no ha ocurrido en Antofagasta· Este trabajo analiza esta diferencia a partir del rol de las escalas de producción en el sector minero. Utilizando un análisis de sensibilidad para un modelo insumo-producto desagregado, se calculan encadenamientos y multiplicadores por escalas de producción a nivel regional. Esta estrategia permite identificar y cuantificar el impacto de cada escala de producción, confirmando efectos heterogéneos de la minería sobre la producción e ingreso local, aspectos que adquieren especial relevancia al analizarse la política minera actual en Chile.

  7. Rapid reduction in breast cancer mortality with inorganic arsenic in drinking water.

    Science.gov (United States)

    Smith, Allan H; Marshall, Guillermo; Yuan, Yan; Steinmaus, Craig; Liaw, Jane; Smith, Martyn T; Wood, Lily; Heirich, Marissa; Fritzemeier, Rebecca M; Pegram, Mark D; Ferreccio, Catterina

    2014-11-01

    Arsenic trioxide is effective in treating promyelocytic leukemia, and laboratory studies demonstrate that arsenic trioxide causes apoptosis of human breast cancer cells. Region II in northern Chile experienced very high concentrations of inorganic arsenic in drinking water, especially in the main city Antofagasta from 1958 until an arsenic removal plant was installed in 1970. We investigated breast cancer mortality from 1950 to 2010 among women in Region II compared to Region V, which had low arsenic water concentrations. We conducted studies on human breast cancer cell lines and compared arsenic exposure in Antofagasta with concentrations inducing apoptosis in laboratory studies. Before 1958, breast cancer mortality rates were similar, but in 1958-1970 the rates in Region II were half those in Region V (rate ratio RR = 0·51, 95% CI 0·40-0·66; parsenic concentrations close to those estimated to have occurred in people in Region II. We found biologically plausible major reductions in breast cancer mortality during high exposure to inorganic arsenic in drinking water which could not be attributed to bias or confounding. We recommend clinical trial assessment of inorganic arsenic in the treatment of advanced breast cancer.

  8. Differential response to ocean acidification in physiological traits of Concholepas concholepas populations

    Science.gov (United States)

    Lardies, Marco A.; Arias, María Belén; Poupin, María Josefina; Manríquez, Patricio H.; Torres, Rodrigo; Vargas, Cristian A.; Navarro, Jorge M.; Lagos, Nelson A.

    2014-07-01

    Phenotypic adaptation to environmental fluctuations frequently occurs by preexisting plasticity and its role as a major component of variation in physiological diversity is being widely recognized. Few studies have considered the change in phenotypic flexibility among geographic populations in marine calcifiers to ocean acidification projections, despite the fact that this type of study provides understanding about how the organism may respond to this chemical change in the ocean. We examined the geographic variation in CO2 seawater concentrations in the phenotype and in the reaction norm of physiological traits using a laboratory mesocosm approach with short-term acclimation in two contrasting populations (Antofagasta and Calfuco) of the intertidal snail Concholepas concholepas. Our results show that elevated pCO2 conditions increase standard metabolic rates in both populations of the snail juveniles, likely due to the higher energy cost of homeostasis. Juveniles of C. concholepas in the Calfuco (southern) population showed a lower increment of metabolic rate in high-pCO2 environments concordant with a lesser gene expression of a heat shock protein with respect to the Antofagasta (northern) population. Combined these results indicate a negative effect of ocean acidification on whole-organism functioning of C. concholepas. Finally, the significant Population × pCO2 level interaction in both studied traits indicates that there is variation between populations in response to high-pCO2 conditions.

  9. "Situación de inmigración" de mujeres sudamericanas en chile: hacia un modelo comprensivo

    Directory of Open Access Journals (Sweden)

    Leyla Méndez Caro

    2012-01-01

    Full Text Available El objetivo de esta investigación fue conocer la situación de inmigración de mujeres sudamericanas en la región de Antofagasta (Chile y construir un modelo teórico para su análisis. Las participantes de este estudio fueron 19 mujeres de entre 18 y 50 años, residentes en la ciudad de Antofagasta y provenientes de Perú, Bolivia y Colombia. Los principales hallazgos sugirieron un modelo dinámico, en el que se tensiona la identidad social y de género de las mujeres inmigrantes ante la búsqueda de coherencia dentro de sus espacios vitales. Advertimos en la interacción con la sociedad receptora, la imposición de nuevas categorías sociales a cambio de integración basada en la asimilación. No obstante, también se observan formas de resistencia frente a dicho proceso.

  10. Structure and Evolution of the Central Andes of Peru

    Science.gov (United States)

    Gonzalez, L.; Pfiffner, O. A.

    2009-04-01

    Three major units make up the Andes in Peru: (1) The Western Cordillera consists of the Cretaceous Coastal Batholith intruding Jurassic to Cretaceous volcaniclastics (Casma group) in the west, and a fold-and-thrust belt of Mesozoic sediments in the east. Eocene and Miocene volcanics (Calipuy group and equivalents) overly all of these rock types. (2) The Central Highland contains a folded Paleozoic-Mesozoic sedimentary sequence overlain by thick Quaternary deposits. A major fault puts Neoproterozoic basement rocks of the Eastern Cordillera next to these units. (3) In the Eastern Cordillera, Late Paleozoic clastic successions unconformably overly folded Early Paleozoic sediments and a Neoproterozoic basement in the east. Permian (locally Triassic) granitoids intruded these units and were affected by folding and thrusting. In the core of the Eastern Cordillera, Early Cretaceous overly Early or Late Paleozoic strata. To the west, a thrust belt of Paleozoic to Cenozoic strata forms the transition to the foreland of the Brasilian shield. The most external part of this thrust belt involves Pliocene sediments and is referred to as Subandine zone. The Coastal Batholith is internally undeformed. The adjacent fold-and-thrust belt to the east is characterized by tight, nearly isoclinal upright folds with amplitudes of up to 1000 m. At the surface only Cretaceous rocks are observed. Using balancing techniques, a detachment horizon at the base of the Lowermost Cretaceous (Goyallarisquizga group - Oyon Formation) can be proposed. Further east, folds are more open, asymmetric and east verging, Jurassic sediments appear in the cores of the anticlines. The abrupt change in style from upright tight folding in the west to more open folding in the east is explained by a primary difference in the depositional sequence, most probably associated with synsedimentary faulting. The overlying volcanics of the Calipuy group and equivalents are, in turn, only slightly folded. In the Northern

  11. EFECTO POST-INCENDIO SOBRE EL ECOSISTEMA Araucaria-Nothofagus, PARQUE NACIONAL TOLHUACA.

    OpenAIRE

    PAULINO, LEANDRO

    2006-01-01

    Las comunidades boscosas de Araucaria-M'rhofagus de la Cordillera de Los Andes en Chile y Argentina se han adaptado a los evenlos catastróficos de incendio, los cuales tienen una frecuencia histórica que últimamente se ha incrementado junto a la severidad 186p.

  12. The paleobotanical record of Colombia: Implications for biogeography and biodiversity

    NARCIS (Netherlands)

    Hooghiemstra, H.; Wijninga, V.M.; Cleef, A.M.

    2006-01-01

    Plant microfossil and macrofossil associations obtained from six dated sections from the area of the basin of Bogota¿ (2550 m, Eastern Cordillera, Colombia) show the evolution of the late Neogene Andean montane forest, triggered by the Andean orogeny. Progressive adaptation of warm tropical taxa to

  13. A robust and well-resolved phylogeny of Bactridinae (Arecaceae) based on plastid and nuclear DNA sequences

    DEFF Research Database (Denmark)

    Eiserhardt, Wolf L.; Pintaud, Jean-Christophe; Asmussen-Lange, Conny

    Aiphanes shows an initial radiation of early lineages in the Oligocene (26 mya) corresponding to an early uplift phase of the cordillera. These taxa have today a relict distribution in mountain forests of Colombia and Ecuador. The major diversification of Aiphanes began in the Miocene (around 11 mya...

  14. Andean waterways

    DEFF Research Database (Denmark)

    Rasmussen, Mattias Borg

    , social, and cultural concerns. Set in the highland town of Recuay in Ancash, the book traces the ways in which water affects political and ecological relations as glaciers recede. By looking at the shared waterways of four villages located in the foothills of Cordillera Blanca, it addresses pertinent...

  15. Constraints on deformation of the Southern Andes since the Cretaceous from anisotropy of magnetic susceptibility

    NARCIS (Netherlands)

    Maffione, Marco; Hernandez-Moreno, Catalina; Ghiglione, Matias C.; Speranza, Fabio; van Hinsbergen, Douwe J.J.; Lodolo, Emanuele

    2015-01-01

    The southernmost segment of the Andean Cordillera underwent a complex deformation history characterized by alternation of contractional, extensional, and strike-slip tectonics. Key elements of southern Andean deformation that remain poorly constrained, include the origin of the orogenic bend known

  16. Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.

    2009-01-01

    Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 in were examined along two altitudinal transects crossing the

  17. A phytosociological study of the páramo along two altitudinal transects in El Carchi province, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.

    2009-01-01

    We here present a plant composition study of páramo grasslands in the East Andean Cordillera of northern Ecuador that discerns altitudinal distribution patterns. This study took place at two locations: the relatively undisturbed Guandera Biological Reserve site and the highly disturbed El Angel

  18. Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.

    2009-01-01

    Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 m were examined along two altitudinal transects crossing the

  19. A phytosociological study of the paramo along two altitudinal transects in El Carchi province, northern Ecuador

    NARCIS (Netherlands)

    Moscol Olivera, M.C.; Cleef, A.M.

    2009-01-01

    We here present a plant composition study of paramo grasslands in the East Andean Cordillera of northern Ecuador that discerns altitudinal distribution patterns. This study took place at two locations: the relatively undisturbed Guandera Biological Reserve site and the highly disturbed El Angel

  20. Steady-state exhumation pattern in the central Andes SE Peru

    NARCIS (Netherlands)

    Ruiz, G.M.H.; Carlotto, V.; van Heiningen, P.S.; Andriessen, P.A.M.

    2009-01-01

    The Western Cordillera of SE Peru is part of the Central Andes and is situated to the west of the Eastern Andes from which it is separated by the northern termination of the Altiplano - the Inter-Andean Valley. It is a volcanic-volcano-detrital chain that developed in the Palaeogene, and is

  1. Aptychi from the Berriasian/Valanginian (France and Spain): New stratigraphical and morphological details

    Czech Academy of Sciences Publication Activity Database

    Vašíček, Zdeněk; Janssen, N. M. M.; Klein, J.

    2016-01-01

    Roč. 86, č. 3 (2016), s. 265-272 ISSN 0208-9068 Institutional support: RVO:68145535 Keywords : Lamellaptychi * Berriasian/Valanginian * Vocontian Basin * Betic Cordillera Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.833, year: 2016 http://www.asgp.pl/sites/default/files/volumes/86_3_265_272.pdf

  2. El Camino Inca de la Costa en Tumbes

    OpenAIRE

    Vílchez Carrasco, Carolina; Ministerio de Cultura

    2015-01-01

    Artículo descriptivo sobre el camino inca de la costa de Tumbes y sus tres subtramos: en la cordillera de Amotapes, en las colinas miocénicas y en la planicie litoral. Abarca temas como el medio geográfico, los antecedentes del estudio y la historia del tramo.

  3. Vegetation types on Mount Akiki, Northern Luzon, Philippines

    NARCIS (Netherlands)

    Bout, I.E.

    2002-01-01

    Mount Akiki (16° 37’ N, 120° 53’ E, c. 2760 m alt.) is one of the highest mountain peaks in the Cordillera mountain range, Luzon Island, Philippines. It is situated in the municipality of Benguet, north-east of Baguio City (a world famous tourist city in the region) and is north-west of Mt Pulog,

  4. Important Crustal Growth in the Phanerozoic: Isotopic Evidence of ...

    Indian Academy of Sciences (India)

    Such idea of negligible growth in the Phanerozoic is now challenged by the revelation of very large volume of juvenile crust produced in the period of 500 to 100 Ma in several orogenic belts. While appreciable volumes of juvenile terranes in North America (Canadian Cordillera, Sierra Nevada and Peninsular Range, ...

  5. Late-orogenic extension and strike-slip deformation in the Neogene of southeastern Spain

    NARCIS (Netherlands)

    Meijninger, B.M.L.

    2006-01-01

    The Betic Cordillera of southern Spain form the western end of the Alpine orogen, which during the Neogene was affected by large-scale late-orogenic extension. Extension, however, occurred within a setting of continuous slow convergence of the African and European plates. During the Neogene,

  6. A regional view of fluctuations in glacier length in southern South America

    NARCIS (Netherlands)

    Lopez, P.; Chevallier, P.; Favier, V.; Pouyaud, B.; Ordenes, F.; Oerlemans, J.|info:eu-repo/dai/nl/06833656X

    2010-01-01

    Fluctuations in the length of 72 glaciers in the Northern and Southern Patagonia Icefield (NPI and SPI, respectively) and the Cordillera Darwin Icefield (CDI) were estimated between 1945 and 2005. The information obtained from historical maps based on 1945 aerial photographs was compared to ASTER

  7. A Holocene pollen record of vegetation change and human impact from Pantano de Vargas, an intra-Andean basin of Duitama, Colombia

    NARCIS (Netherlands)

    Gomez, A.; Berrio, J.C.; Hooghiemstra, H.; Becerra, M.; Marchant, R.

    2007-01-01

    Holocene environments in the intra-Andean basin of Duitama (Eastern Cordillera of Colombia, 2510 m altitude) are presented based on the 620 cm long Vargas pollen and sediment record. Seven AMS radiocarbon dates show these lake and swamp sediments represent the period from 8800 to 2610 14C yr BP. We

  8. Contribution to the Triassic ostracode faunas of the Betic Zone (southern Spain)

    NARCIS (Netherlands)

    Kozur, H.; Kampschuur, W.; Mulder-Blanken, C. W. H.; Simon, O.J.

    1974-01-01

    Ostracodes are reported for the first time from epimetamorphic, strongly tectonized Triassic rock sequences from the internal part of the Betic Cordilleras. Three ostracode-zones have been established. The lower and middle zones are attributed to the Late Ladinian (Longobardian) and the upper zone

  9. AVIAN DISTRIBUTION IN DOMINICAN SHADE COFFEE PLANTATIONS: AREA AND HABITAT RELATIONSHIPS

    Science.gov (United States)

    JOSEPH M . WUNDERLE JR

    1999-01-01

    Residentsa nd wintering Nearctic migrantsw ere sampledb y point countsi n 40 smallt o medium-sized(0 .07-8.65 ha) shadec offeep lantationsw ith an overstoryo f Inga vera in the Cordillera Central, Dominican Republic. The purpose of the study was to determine the relative importance of plantation area, isolation, and habitat structure to avian distribution and abundance...

  10. Tundra, Chapter 5

    Science.gov (United States)

    K. Nadelhoffer; L.H. Geiser

    2011-01-01

    The North American Arctic, comprising the Tundra and Arctic Cordillera ecoregions (CEC 1997, Chapter 2), covers more than 3 million km2 (300 million ha), and accounts for nearly 14 percent of the North American land mass. The North American Arctic also constitutes about 20 percent of the much larger circumpolar Arctic shared by Canada, the United...

  11. Geology of the eastern zone of the Sierra del Brezo (Palencia-Spain)

    NARCIS (Netherlands)

    Kanis, J.

    1956-01-01

    In het noordwestelijk deel van de provincie Palencia vormt de Sierra del Brezo een onderdeel van de Cordillera Cantábrica. Het resultaat van een geologische kaartering van het oostelijk gedeelte der Sierra del Brezo met zijn aangrenzend gebied is weergegeven in de hier bijgevoegde geologische kaart

  12. The species of the genus Pseudoniphargus Chevreux, 1901 (Amphipoda) from northern Spain

    NARCIS (Netherlands)

    Notenboom, Jos

    1986-01-01

    Based on new material collected in 1983, 1984, and 1985, the genus Pseudoniphargus proves to be distributed in northern Spain from Asturias, in the western part of the Cordillera Cantabrica, to Navarra and Huesca, in the headlands of the Pyrenees; and from coastal Atlantic regions up to the northern

  13. The geology of the southern part of the Pisuerga basin and the adjacent area of Santibañez de Resoba, Palencia, Spain

    NARCIS (Netherlands)

    Frets, D.C.

    1965-01-01

    The ”Cordillera Cantabrica”, which borders the Old-Castilian meseta in the north, is mainly a Hercynian mountain chain. The area with which this study is concerned is part of the southern border of this mountain belt and lies in the northeast in part of the province of Palencia. The topographic

  14. 78 FR 44538 - Caribbean Fishery Management Council; Public Meetings

    Science.gov (United States)

    2013-07-24

    ... Aggregation Project Update--Richard Appeldoorn/Michel Sharer Tales from La Cordillera: Promoting Sustainable Fishing through Environmental Interpretation--Alejandro Torres Outreach and Education Meeting Report... Executive Director's Report Scoping Meetings Report on the Development of Island-Based Fishery Management...

  15. Paleozoic paleogeographic and depositional developments on the central proto-Pacific margin of Gondwana: Their importance to hydrocarbon accumulation

    Science.gov (United States)

    Gohrbandt, K. H. A.

    1992-11-01

    During the Paleozoic Era, the western portion of the Gondwana continent between the equator and latitude 27°S of present-day South America bordered the proto-Pacific Ocean as a predominantly convergent margin. Following the Middle Cambrian accretion of the Arequipa-Belen-Antofalla Terrane, an epicontinental sea with communication to the proto-Pacific Ocean established itself along the length of the western margin of Gondwana during Late Cambrian and Early Ordovician time. The emergence of a proto-Cordillera led to significant separation of the epicontinental sea from the proto-Pacific Ocean during Silurian and Devonian times. Gradual erosion of that proto-Cordillera during Carboniferous and Early Permian time once again facilitated widespread transgression of the proto-Pacific Ocean into the epicontinental domain. At the end of the Early Permian, the sea retreated from Gondwana and a proto-Cordillera was re-established. The proto-Cordillera and the craton of Gondwana controlled sediment type and distribution in the epicontinental sea. Deposition occurred in five tectono-sedimentary cycles, which were separated by orogenic pulses that resulted in regional erosion of the previously deposited section. Oil and gas have been produced from the Paleozoic epicontinental sediments of Argentina, Bolivia, Peru, and Brazil, in an area in which exploration efforts are ongoing. Sandstone reservoirs and argillaceous source rocks of commercial importance formed during the episodes of sedimentation, but carbonates do not contribute to commercial hydrocarbon generation and accumulation. Cap rocks are provided by shales or evaporites.

  16. String of turquoise: The future of Sacred Mountain Peaks in the southwest U.S.

    Science.gov (United States)

    Linda Moon Stumpff

    2011-01-01

    The Southwest is the birthplace of wilderness policy in the United States, yet the unique ecological environments of its peaks, cordilleras, and ranges that dot the high desert remain only partially protected. Some areas are relatively secure, yet midcentury Federal policy responded to multiple development pressures, from ski basins to roads, that sliced these peaks...

  17. The dynamic history of the upper forest line ecotone in the northern Andes

    NARCIS (Netherlands)

    Hooghiemstra, H.; Berrio, J.C.; Groot, M.H.M.; Bogotá-A, R.G.; Moscol Olivera, M.; González-Carranza, Z.; Myster, R.W.

    2012-01-01

    In the Andean cordilleras very conspicuous ecotones can be found. The transition from continuous upper montane forest to treeless herbaceous vegetation, regionally known as "páramo" (Cleef 1981; Luteyn 1999) is known as the "upper forest line" (UFL) or "timber line" (Holtmeier 2009). Above the UFL