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Sample records for central patagonia chubut

  1. (Leather working among hunter-gatherers from central-northern Patagonia. Campo Moncada 2 (middle Chubut river valley)

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    Marchione, Paula Cecilia; Bellelli, Cristina

    2016-01-01

    En este trabajo se presenta la reconstrucción del proceso productivo de la tecnología del cuero en el sitio Campo Moncada 2, ubicado en el valle de Piedra Parada (Provincia del Chubut). Para ello se considera el concepto de cadena operativa, elaborado sobre la base de modelos experimentales, etnoarqueológicos e información obtenida de diversas fuentes etnohistóricas y etnográficas de la región patagónica centro-septentrional. Asimismo, se propone y aplica un diseño metodológico propio para e...

  2. Detrital zircon geochronology and provenance of the Chubut Group in the northeast of Patagonia, Argentina

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    Navarro, Edgardo L.; Astini, Ricardo A.; Belousova, Elena; Guler, M. Verónica; Gehrels, George

    2015-11-01

    The Chubut Group constitutes the most widespread sedimentary unit in NE Patagonia, characterized by variable-energy fluvial deposits. U-Pb analysis of detrital zircons from two sections of the Chubut Group constraint the age of the oldest sedimentary rocks in the northeast of the Somuncurá - Cañadón Asfalto Basin. In the Cañadón Williams area, at San Jorge section, 20 km NW of Telsen locality, dating of 56 detrital zircons from a medium to coarse sandstone indicated a maximum depositional age of 109 ± 1 Ma (n = 4). These sandstones were interpreted to represent shallow channels, associated with a lacustrine system. In the Telsen locality, a laser ablation analysis of 115 detrital zircons from a medium to coarse-grained sandstone, from fluvial channel facies, yielded a maximum depositional age of ca. 106 ± 1 Ma (n = 8). Both ages are consistent with volcanic events of the Barremian to Albian age in the central Patagonian Andes Region. Cathodoluminescence images of zircons from the San Jorge sample suggest an igneous origin, which is further supported by Th/U values above 0.5 in most of the grains. The distribution of the statistical modes of the main age populations of detrital zircons for the two samples [182, 185 and 189 Ma for Telsen sample (T2S) and 181 ± 1 Ma for San Jorge sample (SJS)] matches the age of the volcanic Marifil Formation. The rocks of the Marifil Formation of these ages are exposed NE to SE of the study area. The abundance of zircons of similar Jurassic ages (n = 52 for SJS and n = 105 for T2S) and the external morphology of the zircons in the sample SJS, implies a close proximity of the source area. Suggestion that the Marifil Formation was the main provenance source is also supported by northeast-southeasterly paleocurrents measured at the San Jorge and Telsen sections.

  3. Polen de las Mieles de la Patagonia Andina (Chubut-Argentina Pollen of honeys from the Andean Patagonia (Chubut-Argentina

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    Alicia Forcone

    2006-07-01

    Full Text Available Se describen e ilustran mediante fotomicrografías tomadas con MO y MEB, 30 tipos polínicos, determinados en las mieles producidas en la región andina de Chubut (Patagonia Argentina. Los tipos morfológicos descriptos pertenecen a las siguientes familias: Alstroemeriaceae, Apiaceae, Buddlejaceae, Caryophyllaceae, Caprifoliaceae, Celastraceae, Clusiaceae, Convolvulaceae, Ericaceae, Elaeocarpaceae, Fabaceae, Fagaceae, Lamiaceae, Papaveraceae, Polemoniaceae, Polygalaceae, Proteaceae, Ranunculaceae, Rosaceae, Saxifragaceae, Solanaceae, Thymelaceae y Verbenaceae. La mayoría de los tipos polínicos descriptos fueron hallados en las mieles como polen de menor importancia o traza con excepción de Aristotelia chilensis y Escallonia sp., que alcanzaron la categoría de polen dominante, y de Lomatia hirsuta, hallada como polen secundario.Thirty pollen types identified in the honeys from the Andean region of Chubut are described and illustrated by means of LM and SEM photomicrographs. Pollen types belong to the following families: Alstroemeriaceae, Apiaceae, Buddlejaceae, Caryophyllaceae, Caprifoliaceae, Celastraceae, Clusiaceae, Convolvulaceae, Ericaceae, Elaeocarpaceae, Fabaceae, Fagaceae, Lamiaceae, Papaveraceae, Polemoniaceae, Polygalaceae, Proteaceae, Ranunculaceae, Rosaceae, Saxifragaceae, Solanaceae, Thymelaceae, and Verbenaceae. Most pollen types described were found in the honeys as minor important pollen or traces, except Aristotelia chilensis, Escallonia sp., which reached the category of dominant pollen, and Lomatia hirsuta, which was found as secondary pollen.

  4. Depositional Environments of Late Danian Plant Localities: Chubut Provice, Patagonia, Argentina

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    Comer, E.; Slingerland, R. L.; Wilf, P.

    2010-12-01

    Diverse, well-preserved macroflora are observed within Cretaceous and Paleocene sediments of Chubut Province, Patagonia, Argentina. These macroflora are the most well preserved early Paleocene flora from Gondwana and add new insight into the diversity and environments of that epoch. Two major sites of fossil preservation, Palacio de los Loros and Parque Provincial Ormachea, sit near the top of the Late Danian (65.5-61.7 Ma) Salamanca Formation. Understanding the depositional history of the Salamanca is important in characterizing paleoenvironments in which these flora lived and relating these Patagonian macroflora to concurrent Paleocene flora within the Gondwanan supercontinent. During a two week field season, twenty stratigraphic sections were measured along the outcrop belt at Palacio de los Loros and Ormachea Park as well as two minor sites; Las Flores, and Rancho Grande. Photo mosaics, laser ranger data, and stratigraphic columns were merged with elevated geologic maps and imported into Fledermaus to generate a 3-D visualization of facies relationships. Rock samples were also collected and will be thin sectioned and analyzed for petrography and grain size. The Salamanca Fm. consists of 7 facies, listed here in stratigraphically ascending order: 1)Transgressive sands, 2)Wispy-bedded claystone, 3)Banco Verde, 4)White Cross bedded sandstone, 5)Accretion set siltstone, 6)Transitional silty claystone and 7)Banco Negro. Based on these facies, the Salamanca Fm. is interpreted as a marine-shelf to brackish, tide-dominated, estuarine deposit. The base of the Salamanca Fm. rests on an unconformity representing a marine flooding surface and lower sections of the Salamanca, facies 1 and 2, contain abundant glauconite and fossils indicative of a marine shelf environment. These facies give way upwards to bi-directional trough cross bedded sandstones interspersed with flaser bedded sandy siltstones (facies 3 and 4) indicating a less marine estuary with strong flow regimes

  5. Patrimonio arqueológico, memoria y territorio. Procesos de autoctonización entre los mapuches de Lago Puelo, Chubut (Patagonia, Argentina

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    Carolina Crespo

    2011-01-01

    Full Text Available Este artículo analiza las disputas de sentido que se configuran en torno de la categoría de "autoctonía" en la localidad de Lago Puelo -Comarca Andina del Paralelo 42º, noroeste de Chubut, Patagonia, Argentina-, su articulación con determinados derechos y demandas de la población mapuche y el lugar que ocupa el patrimonio arqueológico en el proceso de autoctonización de esta población dentro de procesos hegemónicos cambiantes. Tal forma de categorización resulta central en las modalidades de construcción de identidades políticas de los pueblos indígenas, de configuración de sus demandas y de las políticas estatales de reconocimiento de derechos hacia estos pueblos.

  6. Un ejemplo excepcional de brechamiento (sismita? en el grupo Chubut, Patagonia An exceptional example of brecciation (seismite? in the Chubut Group, Patagonia

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    Edgardo Navarro

    2010-10-01

    Full Text Available Un brechamiento excepcional en unidades sedimentarias pelíticas del Grupo Chubut en la cercanía de la localidad de Telsen, provincia de Chubut, muestra que han sido afectadas por una etapa de telodiagénesis (diagénesis de exhumación. Presentan evidencias de deformación frágil relacionadas con mecanismos de sobrepresurización. Estos depósitos de edad aptiana, se disponen subhorizontales y constituyen asociaciones fluviales lateralmente extendidas. Un continuo de estructuras sedimentarias deformacionales se desarrollan enteramente sobre los depósitos pelíticos correspondientes a la asociación de facies de llanura de inundación. Cuatro intervalos fueron reconocidos de manera continua: 1 fracturado in situ, 2 brechado, 3 brechado fangosostenido y 4 homogeneizado. Conductos de escape potenciales de diversos tamaños, tienen desarrollo en el intervalo fangosostenido, que en ocasiones llegan a atravesar el intervalo superior homogéneo. El mecanismo de sobrepresurización, se habría visto favorecido por la presencia de cuerpos de areniscas conglomerádicas tobáceas confinantes (capa sello, que impidieron el escape de fluidos, permitiendo la licuefacción parcial a total y fluidización de la rocas sedimentarias de la llanura aluvial. Fallas normales reconocidas en el área, que afectan al Grupo Chubut, constituirían un elemento de juicio para establecer un origen sísmico a estas fábricas brechadas, cuya magnitud habría superado M>5 de la escala Mercalli modificada. La característica reológica frágil del material a partir del cual se originaron, convierte a estas estructuras en un ejemplo natural excepcional de brechamiento a partir de un mecanismo de sobrepresurización fosilizado.Sedimentary units of the Chubut Group in the proximity of the Telsen locality, in Chubut province affected by a telodiagenesis stage, display evidence of brittle deformation related to over-pressurizing mechanisms. These sub-planar deposits of Aptian age

  7. Plantas Medicinales en el Parque Nacional los alerces, Chubut, Patagonia Argentina

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    Carolina Toledo

    2012-12-01

    Full Text Available El objetivo de este estudio fue identificar las plantas con valor medicinal empleadas por los antiguos pobladores del Parque Nacional Los Alerces y relacionarlas con la riqueza específica de plantas medicinales presentes en el área. Se entrevistaron 16 pobladores asentados en la Reserva Nacional que tenían conocimiento de las plantas medicinales, más allá de que hicieran uso o no de las mismas. Las entrevistas fueron semiestructuradas, completadas de manera escrita e individual por el entrevistador. Las mismas incluían diez preguntas que recopilaban información respecto a las especies usadas como medicina, modo de preparación y aplicación, frecuencia de uso, localización de las plantas en el ámbito del área protegida, forma de obtención de las especies, y el modo de adquisición de los conocimientos respecto a las plantas. Los pobladores mencionaron el uso de 42 especies con valor medicinal, distribuidas en 24 familias, de las cuales las mejor representadas fueron Lamiaceae (21,4% y Asteraceae (14,2%. En cuanto al origen de las plantas medicinales citadas por los pobladores, el 58, 5% correspondió a especies exóticas. Los usos más frecuentes fueron para trastornos del sistema digestivo, seguido en orden decreciente y en menor proporción para tratar afecciones respiratorias, cardiovasculares y de la piel. Al comparar la riqueza total de especies medicinales presentes en el Parque y las registradas a partir de las entrevistas, se observa que se hace uso de un 28,6% de lo disponible en el área.Medicinal plants in The Alerces National Park, Chubut, Argentinean Patagonia. The aim of this study was to identify the medicinal plants used by the old residents in The Alerces National Park and to relate this information with medicinal species richness in the area. An interview was employed with 16 local people settled in the National Reserve who had knowledge of medicinal plants, past or not to make use of them. The interviews were semi

  8. Un ejemplo excepcional de brechamiento (sismita? en el grupo Chubut, Patagonia

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    Edgardo Navarro

    2010-10-01

    Full Text Available Un brechamiento excepcional en unidades sedimentarias pelíticas del Grupo Chubut en la cercanía de la localidad de Telsen, provincia de Chubut, muestra que han sido afectadas por una etapa de telodiagénesis (diagénesis de exhumación. Presentan evidencias de deformación frágil relacionadas con mecanismos de sobrepresurización. Estos depósitos de edad aptiana, se disponen subhorizontales y constituyen asociaciones fluviales lateralmente extendidas. Un continuo de estructuras sedimentarias deformacionales se desarrollan enteramente sobre los depósitos pelíticos correspondientes a la asociación de facies de llanura de inundación. Cuatro intervalos fueron reconocidos de manera continua: 1 fracturado in situ, 2 brechado, 3 brechado fangosostenido y 4 homogeneizado. Conductos de escape potenciales de diversos tamaños, tienen desarrollo en el intervalo fangosostenido, que en ocasiones llegan a atravesar el intervalo superior homogéneo. El mecanismo de sobrepresurización, se habría visto favorecido por la presencia de cuerpos de areniscas conglomerádicas tobáceas confinantes (capa sello, que impidieron el escape de fluidos, permitiendo la licuefacción parcial a total y fluidización de la rocas sedimentarias de la llanura aluvial. Fallas normales reconocidas en el área, que afectan al Grupo Chubut, constituirían un elemento de juicio para establecer un origen sísmico a estas fábricas brechadas, cuya magnitud habría superado M>5 de la escala Mercalli modificada. La característica reológica frágil del material a partir del cual se originaron, convierte a estas estructuras en un ejemplo natural excepcional de brechamiento a partir de un mecanismo de sobrepresurización fosilizado.

  9. Sapling growth and crown expansion in canopy gaps of Nothofagus pumilio (lenga) forests in Chubut, Patagonia, Argentina

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    Lopez Bernal, P. M.; Defosse, G. E.; Quinteros, C. P.; Bava, J. O.

    2012-07-01

    In the province of Chubut in Patagonia, Argentina, Nothofagus pumilio forests (locally known as lenga), are managed through selective cuts, which imply the opening of canopy gaps. This management scheme is carried out without taking into consideration the changes of sapling requirements through either a cutting cycle or the precipitation gradient in which these forests thrive. To analyze these changes, we inferred the facilitation-competition balance between the canopy and regeneration, studying the effects of precipitation levels, gap size and gap age on saplings growth in height on 45 canopy gaps artificially created between 1960 and 1993. Results showed that during the first 20 years since gap opening, growth of regeneration is determined by light availability in mesic sites and by water availability in xeric sites. However, differences due to precipitation levels gradually decrease over time. Moreover, in the period between 20 and 35 years after gap opening, in both mesic and xeric sites, growth is limited by light availability. This indicates that in xeric sites, sapling growth requirements shift from a water-dependent situation to a light-dependent situation. The average closing rate of gaps due to lateral growth of bordering trees is high enough so that within the proposed gap size range, gap healing can occur before regeneration reaches the upper stratum. Consequently, in mesic sites gap opening can be done by a single operation that generates gaps with diameters of approximately twice the average height of the canopy (D/H). While in xeric environments, lenga seedling establishment and initial growth require the cover of small gaps, but advanced regeneration requires bigger gaps to reach the canopy. For this reason, gaps should be opened in two stages: the first gaps should be opened with a D/H between 0.8 and 1, and after a cutting cycle of 35 years, these openings should be enlarged to a D/H between 1.5 and 2. The close relationship maintained between the

  10. Episodic Jurassic to Lower Cretaceous intraplate compression in Central Patagonia during Gondwana breakup

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    Navarrete, César; Gianni, Guido; Echaurren, Andrés; Kingler, Federico Lince; Folguera, Andrés

    2016-12-01

    From Lower Jurassic to Lower Cretaceous, several intraplate compression events affected discrete sectors of Central Patagonia, under a general context of crustal extension associated with Gondwana breakup. This was demonstrated by means of 2D and 3D seismic and borehole data, which show partial inversion of Lower and Middle Jurassic extensional structures of the Chubut and Cañadón Asfalto basins, during the earliest stages of breakup. A comparison with surrounding areas in Patagonia, where similar Jurassic intraplate compression was described, allowed the discrimination of three discrete pulses of subtle compression (C1: ∼188-185 Ma; C2: ∼170-163; C3: ∼157-136? Ma). Interestingly, episodic intraplate compressional events are closely followed by high flux magmatic events linked to the westward expansion of the Karoo-Ferrar thermal anomaly, which impacted on the lithosphere of southwest Gondwana in Lower Jurassic. In addition, we determined the approximate direction of the main compressive strain (σ1) compatible with other Jurassic intraplate belts of South America. These observations led us to propose a linkage between a thermo mechanically weakened continental crust due to LIPs activity, changes in plate motions and ridge-push forces generated by the opening of the Weddell Sea, in order to explain intraplate shortening, interrupted while Karoo LIPs magmatic invigoration took place.

  11. Cenomanian-? early Turonian minimum age of the Chubut Group, Argentina: SHRIMP U-Pb geochronology

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    Suárez, Manuel; Márquez, Marcelo; De La Cruz, Rita; Navarrete, César; Fanning, Mark

    2014-03-01

    Four new SHRIMP U-Pb zircon ages older than 93 Ma from samples of the two uppermost formations accumulated in two different depocenters (Golfo de San Jorge and Cañadón Asfalto basins) of the Chubut Group in central Argentinean Patagonia, establish a pre-late Cenomanian-? early Turonian age for the group. It also confirms a coeval and comparable evolution of the two depocenters, where distal pyroclastic material was deposited together with fluvial and lacustrine facies.

  12. Isotopic and fluid-inclusion constraints on the formation of polymetallic vein deposits in the central Argentinian Patagonia

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    Dejonghe, Léon; Darras, Benoît; Hughes, Guillermo; Muchez, Philippe; Scoates, James S.; Weis, Dominique

    2002-03-01

    The lead isotope compositions of galena and the fluid-inclusion systematics of nine barite-bearing polymetallic (Au, Ag, Pb, Zn) deposits of the central Argentinian Patagonia (Chubut and Rio Negro provinces) have been investigated to constrain the compositions and sources of the mineralizing fluids. Most of the deposits occur as veins, with less common wall-rock disseminations and/or stockworks, and are low-sulfidation epithermal deposits hosted in Jurassic volcanic rocks. Fluid-inclusion homogenization temperatures (Th) from quartz and sphalerite from the deposits fall within the range of 100-300 °C, with the highest measured average temperatures for the most eastern deposits (Mina Angela - 298 °C; Cañadón Bagual - 343 °C). The salinities of the hydrothermal fluids at all deposits were low to moderate (≤10.4 equiv. wt% NaCl). Three groups of ore deposits can be defined on the basis of 206Pb/204Pb ratios for galena and these show a general decrease from west to east (from 18.506 to 18.000). The central Argentinian Patagonia deposits have distinctly less radiogenic lead isotope compositions than similar deposits from Peru and Chile, except for the porphyry copper deposits of central and southern Peru. Galena from the Mina Angela deposit is characterized by very low radiogenic lead isotope compositions (18.000Precambrian basement. The geographic trend in lead isotope compositions of both galena and whole rocks indicates a crustal contribution which increases eastwards, also reflected in the strontium-neodymium isotope systematics of the host lavas. Finally, due to the lack of precise age determinations for the central Patagonian polymetallic deposits, a potential link with Andean porphyry copper systems remains an open question.

  13. Distribución geográfica, historia natural y conservación del hurón menor Galictis cuja (Carnivora: Mustelidae en la Patagonia central, Argentina Geographic distribution, natural history and conservation of the lesser grison Galictis cuja (Carnivora: Mustelidae from Central Patagonia, Argentina

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    Marcelo Carrera

    2012-12-01

    Full Text Available El hurón menor, Galictis cuja, tiene una amplia distribución en el territorio patagónico extraandino, aunque sus registros puntuales son escasos. Este trabajo se desarrolló en la provincia del Chubut, Patagonia Central, Argentina. Aquí se aportan nuevas localidades de registro de G. cuja para esta región; se discuten aspectos de su distribución geográfica y conservación en el Área Natural Protegida Península Valdés (ANP-PV; Patrimonio Natural de la Humanidad y brevemente se explora la representación de G. cuja en los ensambles de carnívoros del ANP-PV desde el Holoceno tardío hasta la actualidad. Se adicionaron 18 nuevos registros de G. cuja en Patagonia central. Se detectó un conflicto entre los pobladores y hurones, que motiva la caza de estos últimos. Se verificó un aparente incremento de abundancia de G. cuja en los últimos miles de años, concomitante con la extinción regional o dramática disminución de Lyncodon patagonicus (Carnivora, Mustelidae.The Lesser Grison, Galictis cuja, is a species widely distributed in extra-Andean Patagonia, although its records are scarce. This work was carried out in Chubut province, Central Patagonia, Argentina. Here we report new occurrence localities of G. cuja for this region; we discuss aspects of their geographical distribution and conservation in the Área Natural Protegida Península Valdés (ANP-PV; World Heritage Site and briefly explores the representation of G. cuja in carnivore assemblages of ANP-PV, since the late Holocene to the present. We added 18 new records of G. cuja in Central Patagonia. We detected a conflict between the rural residents and the Lesser Grison, which motivates the hunting of the latter. There was an apparent increase in abundance of G. cuja in the last thousands of years, concomitant with regional extinction or dramatic reduction of Lyncodon patagonicus (Carnivora, Mustelidae.

  14. Contexto de las políticas agrarias en los proyectos de desarrollo para Patagonia: el "Informe Altimir" en la provincia de Chubut (1970

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    Gonzalo Pérez Álvarez

    2015-12-01

    Full Text Available El “Informe Altimir” es un trabajo solicitado por el Consejo Federal de Inversiones (CFI a un equipo de investigadores dirigido por Oscar Altimir, para ser entregado a la Asesoría de Desarrollo de Chubut en 1970.Su objetivo era planificar las acciones para la instalación del modelo de "polos de desarrollo" así como analizar las políticas a seguir en las otras áreas económicas. A través de una revisión exhaustiva de esta fuente, y de su cruce con otros aportes, mostramos cuáles fueron las políticas agrarias que se impulsaron en Chubut.Se dividió la provincia en regiones, para impulsar un proyecto que buscara asegurar el suministro de alimentos a las áreas urbanas, la provisión de mano de obra para las industrias a instalarse y la concentración de la propiedad en el resto de Chubut.

  15. Corrales de piedra, campos abiertos y pampas de camaruco: Memorias de relacionalidad en la meseta central de Chubut Stone yards, open fields and sacred places: Memories of relatedness in the Chubut´s central plateau

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    Ana Ramos

    2008-12-01

    Full Text Available La "cuestión indígena" como política de estado en Argentina ha estado acompañada por la elaboración académica de mapas étnicos. Las definiciones hegemónicas de estas entidades han presupuesto generalmente algún elemento "esencial" como, por ejemplo, fenotipos, uso de una lengua, o la aglutinación en torno a linajes consanguíneos. A partir de las reformulaciones de las teorías del parentesco desde el modelo heurístico de las sociedades de casas y las teorías sobre la relacionalidad proponemos una aproximación a la memoria social como marco alternativo de interpretación histórica. Esta contempla las prácticas sociales del parentesco y la objetivación de la continuidad de los grupos de pertenencia en las políticas y lugares de la memoria -corrales de piedra, actividades productivas y pampas de camaruco- en la región de la "meseta" de Chubut. Dichas relaciones con el espacio físico cuestionan tanto las definiciones académicas tradicionales de parentesco y de cacicazgo como las clasificaciones étnicas-nacionales.The "Indigenous issue" as a state policy in Argentina has been accompanied by an academic production of ethnic maps. Hegemonic definitions of these entities used to presume some "essential" elements like the phenotype, the use of language or consanguineous lineage membership. Based on the reformulation of kinship theory, which came from the heuristic model of houses and relatedness theory, we propose an approach to social memory as an alternative framework for historical interpretation. This includes kinship social practices as well as the materialization of group membership's continuity in policies and places of memory -such as stone yards, productive activities, open fields and sacred places- in the Chubut central plateau. Finally, we argue that regarding a physical space, these relations question not only the ethnic-national classifications but also the traditional academic definitions of kinship and chieftaincy.

  16. Gastrointestinal helminths of Commerson's dolphins Cephalorhynchus commersonii from central Patagonia and Tierra del Fuego.

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    Berón-Vera, B; Pedraza, S N; Raga, J A; Gil de Pertierra, A; Crespo, E A; Alonso, M K; Goodall RNP

    2001-12-05

    The stomachs and intestines of 9 Commerson's dolphins incidentally caught in trawl nets in central Patagonia and 23 stranded on beaches in Tierra del Fuego were surveyed for helminth parasites. A total of 267 individuals belonging to 4 species of parasites (1 nematode, 3 digeneans) were found in the dolphins from the first area: Anisakis sp. (larvae type 1 = A. simplex), Braunina cordiformis, Hadwenius sp. and Pholeter gastrophilus. In the Tierra del Fuego dolphins, 142 specimens belonging to 3 species (2 nematodes, 1 digenean, 1 cestode) were found: A. simplex, Hadwenius sp. and Strobilocephalus triangularis. Only 2 of the helminth species were shared in the 2 study areas, A. simplex and Hadwenius sp., and both were more common in central Patagonia. Among the species, A. simplex was most prevalent and abundant in both study areas. In Tierra del Fuego, adults of A. simplex appeared in only 1 host. Hadwenius sp., P. gastrophilus and S. triangularis are new host records for Commerson's dolphin. Species diversity and species richness were low in both study areas. Helminth communities were more diverse in central Patagonia (t = 1.97, df = 258, p Fuego. The results may suggest some differences in habitat use, diet and sex between Commerson's dolphin populations in the 2 study areas.

  17. Petrogénesis de los thundereggs en domos riolíticos del centro del Chubut, Patagonia Petrogenesis of thundereggs in Eocene rhyolite domes of central Chubut, Patagonia

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    E. Aragón

    2006-09-01

    Full Text Available Se describen los thundereggs que se encuentran en domos vitrofíricos de la caldera de Piedra Parada. Tanto las características geológicas, petrológicas como geoquímicas sugieren que estos crecen a partir de gotas de líquidos inmiscibles que se desvitrificaron como esferulitas de anortoclasa. La expansión de la fase vapor segregada al desvitrificarse las gotas inmiscibles, rompieron las esferulitas y desarrollaron grandes vesículas tapizadas por los pedazos rotos de la esferulita. El inmediato enfriamiento del resto del magma dio lugar a la formación de un domo vítreo con textura perlítica. Posteriormente, agua a baja temperatura lixivió al vidrio esferulítico y rellenó las cavidades de las vesículas y esferulitas con ópalo y/o calcedonia.Thundereggs at the glass domes of Piedra Parada Caldera are described. Their geological, petrological and geochemical characteristics suggest growth from immiscible liquid drops that devitrified as anorthoclase spherulites. The expansion of the segregated vapor phase of the devitrified immiscible drops broke the spherulites and made large vesicles lined with the broken pieces of the spherulite. Further cooling of the rest of the magma yielded a glass dome with perlitic texture. Low temperature water lixiviated the perlitic glass and spherulites, filling the cavities within the vesicles and broken spherulite with opal and/or chalcedony.

  18. Petrogénesis de los thundereggs en domos riolíticos del centro del Chubut, Patagonia Petrogenesis of thundereggs in Eocene rhyolite domes of central Chubut, Patagonia

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    E. Aragón; J.A. Saadi; M.C. Ubaldón; A.M. Kuck; C.E. Cavarozzi; Y.E. Aguilera; A. Ribot; González, S

    2006-01-01

    Se describen los thundereggs que se encuentran en domos vitrofíricos de la caldera de Piedra Parada. Tanto las características geológicas, petrológicas como geoquímicas sugieren que estos crecen a partir de gotas de líquidos inmiscibles que se desvitrificaron como esferulitas de anortoclasa. La expansión de la fase vapor segregada al desvitrificarse las gotas inmiscibles, rompieron las esferulitas y desarrollaron grandes vesículas tapizadas por los pedazos rotos de la esferulita. El inmediato...

  19. Las investigaciones de Campo Nassif 1, Valle de Piedra Parada, Provincia del Chubut

    OpenAIRE

    Onetto, María

    1987-01-01

    El presente trabajo forma parte de las investigaciones que se han venido desarrollando desde 1979 como parte del Proyecto de Rescate del Patrimonio Arqueológico de la Provincia del Chubut: zona del río Chubut Medio (Aschero y otros, 1983). En un trabajo anterior informamos sobre los resultados preliminares de nuestras investigaciones en el sitio Campo Nassif 1 (Onetto, 1983). Posteriormente –en las Primeras Jornadas de Arqueología de la Patagonia- comunicamos la obtención de un fechado radioc...

  20. Procedencia de areniscas del Grupo Chubut en el área central de la Sierra de San Bernardo. Análisis preliminar

    OpenAIRE

    M. A. Tunik; M.E. Vietto; J.C. Sciutto; Estrada, E.

    2004-01-01

    Se llevaron a cabo análisis petrográficos de detalle que permitieron determinar las modas detríticas en areniscas del Grupo Chubut con el fin de inferir el marco tectónico del área de aporte de las mismas. Sobre la base de las muestras estudiadas, se observan características petrográficas distintivas entre areniscas de las Formaciones Matasiete, Castillo y Bajo Barreal. La presencia de trizas dentro de las areniscas de las Formaciones Castillo y Bajo Barreal sugeriría una depositación concomi...

  1. Patagonia Argentina

    Directory of Open Access Journals (Sweden)

    A.J. Acuña

    2008-01-01

    Full Text Available La zona central de la Patagonia, Argentina, se encuentra sometida a explotación petrolera y sus suelos se caracterizan por ser deficientes en nitrógeno. Esto causaría un efecto negativo en los procesos de atenuación natural que se desarrollan en los suelos contaminados con hidrocarburos. El objeto de este estudio fue determinar cual es el efecto de la deficiencia de nitrógeno sobre la biodegradación de los hidrocarburos en un suelo de la Patagonia, Argentina. Se trabajó con tres microcosmos a los que se les realizó tratamientos diferentes. En uno se monitoreo la atenuación natural del sistema, en otro la fertilización con nitrógeno (N, fósforo (P y potasio (K, y en el último la fertilización con P y K. Durante el seguimiento se determinaron mineralización y medición de hidrocarburos, y se realizaron recuentos bacterianos y determinación de nitrato, nitrito y amonio. Los resultados indican que es posible la biodegradación de hidrocarburos en el suelo deficiente de nitrógeno de la Patagonia estudiado en tiempos mas prolongados que en aquellos que se realiza una fertilización con nitrógeno. El nitrógeno necesario para el proceso sería obtenido por los microorganismos del suelo por fijación biológica.

  2. Using glacial morphology to constrain the impact of the Chile active spreading ridge subduction in Central Patagonia

    Science.gov (United States)

    Scalabrino, B.; Ritz, J. F.; Lagabrielle, Y.

    2009-04-01

    The Central Patagonian Cordillera is a unique laboratory to study interaction between oceanic and continental lithospheres during the subduction of an active spreading ridge beneath a continent. The subduction of the South Chile spreading Ridge, which separates the Nazca plate from the Antarctic plate, started ca. 15-14 Ma at the southern tip of Patagonia (55°S latitude). The northwards migration of the Chile Triple Junction induces the subduction of several segments especially around 46°S latitude. There, three segments subducted at ca. 6, 3 and 0.3 Ma, leading to the formation of a large asthenospheric slab-window beneath Central Patagonia. Contemporaneously, the Central Patagonia reliefs are undergoing major glacial events since at least 7 Ma. These events are evidenced to the east of the Central Patagonian morphotectonic front within perched relict surfaces. Inset in these perched glacial surfaces are found mid-Pleistocene glacial valleys, as the Lake General Carrera-Buenos Aires amphitheatre (LGCBA), which formed between 1.1 Ma and 16 ka. We used the relationships between the glacial valleys and the volcanism associated with the asthenospheric slab-window to better constraints the structural evolution of the Patagonian Cordillera related to the subduction of the Chili active spreading Ridge. The present work focused within two well-preserved perched flat surfaces named Meseta del Lago Buenos Aires and Meseta del Cerro Galera: (i) The meseta del Lago Buenos Aires defines a plateau made of interbedded units of tills and lavas dated between 12 Ma and 3 Ma. The top surface of the meseta, ˜2000 meters high is dated at 3 Ma, and is shaped by four NE-SW trending glacial lobes characterized with kettles, lineations and moraines. The glacial valleys are beheaded westwards and define perched valleys 200 to 400 meters higher than the western Cordillera. This suggests recent vertical movement along N160 extensive/transtensive corridor located between the morphotectonic

  3. Procedencia de areniscas del Grupo Chubut en el área central de la Sierra de San Bernardo. Análisis preliminar Provenance of the Chubut Group Sandstones in the central area of the Sierra de San Bernardo. Preliminary analysis

    OpenAIRE

    M. A. Tunik; M.E. Vietto; J.C. Sciutto; Estrada, E.

    2004-01-01

    Se llevaron a cabo análisis petrográficos de detalle que permitieron determinar las modas detríticas en areniscas del Grupo Chubut con el fin de inferir el marco tectónico del área de aporte de las mismas. Sobre la base de las muestras estudiadas, se observan características petrográficas distintivas entre areniscas de las Formaciones Matasiete, Castillo y Bajo Barreal. La presencia de trizas dentro de las areniscas de las Formaciones Castillo y Bajo Barreal sugeriría una depositación concomi...

  4. Population genetic structure and historical population dynamics of the South American sea lion, Otaria flavescens, in north-central Patagonia.

    Science.gov (United States)

    Túnez, Juan I; Cappozzo, Humberto L; Nardelli, Maximiliano; Cassini, Marcelo H

    2010-08-01

    The north-central Patagonian coast is the sea lions most abundant area in Argentina. As occurs along the entire Atlantic coast, the distribution of breeding colonies at this smaller geographical scale is also patchy, showing at least three areas with breeding activity. We study the genetic structure and historical population dynamics of the species in five colonies in this area, analysing a 508 base-pair segment of the D-loop control region. Otaria flavescens showed 10 haplotypes with 12 polymorphic sites. The genealogical relationship between haplotypes revealed a shallow pattern of phylogeographic structure. The analysis of molecular variance showed significant differences between colonies, however, pairwise comparisons only indicate significant differences between a pair of colonies belonging to different breeding areas. The pattern of haplotype differentiation and the mismatch distribution analysis suggest a possible bottleneck that would have occurred 64,000 years ago, followed by a demographic expansion of the three southernmost colonies. Thus, the historical population dynamics of O. flavescens in north-central Patagonia appears to be closely related with the dynamics of the Late Pleistocene glaciations.

  5. Petrology of suprasubductive mantle xenoliths from Estancia Sol De Mayo (Central Patagonia, Argentina)

    Science.gov (United States)

    Melchiorre, M.; Coltorti, M.; Gregoire, M.; Benoit, M.

    2012-04-01

    A new suite of mantle xenoliths from Estancia Sol de Mayo (Patagonia) has been investigated. They were entrained in alkaline lavas from the south western sector of Meseta Lago Buenos Aires. Trace element abundances of these lavas are well comparable with those of the main and post-plateau lavas from the Triple Junction Province and resemble those of OIB. Xenoliths are spinel-bearing harzburgites and dunites, with minor lherzolites and one wehrlite. They are characterized by a coarse grained protogranular texture and devoid of modal metasomatic features and hydrated minerals. They show two texturally different clinopyroxenes. One is protogranular (cpx1), while the second surrounds, and is genetically related to, spinel (cpx2). Three different types of orthopyroxenes are also recognized: the first one is represented by large protogranular crystals with exsolution lamellae (opx1), the second one by small clean and undeformed grains without exsolution lamellae (opx2) and the last one occurs as small grains filling veins (opx3). Major element compositions of both clinopyroxenes and orthopyroxenes highlight two different trends. The first one is characterized by high Al2O3 (high-Al trend) content at almost constant mg# [MgO/(MgO+FeO) mol %], while the second shows a slight increase in Al2O3 (low-Al trend) content with decreasing mg#. Trace element contents of cpx are enriched in LREE and characterized by prominent to slightly negative Nb, Zr and Ti anomalies. No differences are observed between cpx1 and cpx2. The three groups of orthopyroxenes are variably depleted in LREE, with opx1 and opx2 always showing prominent to slightly negative Ti and Zr anomalies, while opx3 is characterized by a prominent positive Zr anomaly. Al2O3 in cpx is inversely correlated with LREE and LILE suggesting that a refertilization event occur within the upper mantle beneath Estancia Sol de Mayo. The most likely melt which can account for this event has a tholeiitic affinity, as supported by i

  6. Salud bucal y nutrición en cazadores-recolectores del nordeste del Chubut en el Holoceno

    OpenAIRE

    2009-01-01

    Investigaciones arqueológicas llevadas a cabo en Patagonia centro-septentrional (costa atlántica y valle inferior del río Chubut) demostraron que el área fue utilizada desde por lo menos el Holoceno medio. Estudios de isótopos estables ( 13C y 15N) en muestras óseas humanas indican que los cazadores-recolectores que la ocuparon mantuvieron una dieta mixta que combinó el consumo de guanacos, plantas terrestres, moluscos y pinnípedos. No obstante esta tendencia general, se observó variabilidad ...

  7. The Bajada del Diablo astrobleme-strewn field, central Patagonia Argentina: Extending the exploration to surrounding areas

    Science.gov (United States)

    Acevedo, R. D.; Rabassa, J.; Ponce, J. F.; Martínez, O.; Orgeira, M. J.; Prezzi, C.; Corbella, H.; González-Guillot, M.; Rocca, M.; Subías, I.; Vásquez, C.

    2012-10-01

    The Bajada del Diablo astrobleme-strewn field is a huge domain of enigmatic circular structures located in central Patagonia. Three more localities are herein described, adding to the first area studied so far. Taking into consideration the four areas, a single, blurred crater dispersion ellipse has been identified. The four sectors now have been investigated, mapped, and georreferenced. Their circular structures, with a total of 185 (some of which are partially obliterated by erosion or sediment accumulation), were identified by remote sensing techniques, but many have been evaluated in situ and interpreted as impact craters. Moreover, two of the structures have been surveyed in detail in the field using a total station instrument. In addition to the previously known occurrence of circular structures on the Eruptive Complex Quiñelaf (Miocene basalts), the Pampa Sastre Fm. (Pliocene conglomerates), and of the Pleistocene pediment gravels and sands, and the geomorphological inferences that have suggested the extra-terrestrial origin of this event, we should now add that the recurrent absence of the cited Pliocene stratigraphic unit at the bottom of the craters is found in the pediment gravel and sands. Its removal has been interpreted as directly related to the impact, according to the magnetometric record of existing magnetic anomalies. Other preliminary observations on the collected samples (glass, breccias, and, most relevant, Fe-Ni-bearing spherules picked up within the impact zones) are herein discussed. Two hypotheses have been put forward about the nature of the possible impacting object that formed these astroblemes which, fragmented into hundreds of pieces, hit the surface of the Earth most likely in middle Pleistocene times. One of these hypotheses is related to the impact of a disintegrated asteroid of the rubble pile type, whereas a second hypothesis refers to the collision of a split comet with the Earth surface. The latter hypothesis is favoured since

  8. Presence of Arctotherium (Carnivora, Ursidae, Tremarctinae in a pre-cultural level of Baño Nuevo-1 cave (Central Patagonia, Chile

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    López Mendoza, P.

    2015-12-01

    Full Text Available The description of an I3 assigned to Arctotherium sp. obtained from the Baño Nuevo-1 site (Central Patagonia, Chile is presented. The finding was recovered from Layer 5 and it is associated to Macrauchenia sp., Lama guanicoe, Felidae, Camelidae, Equidae and Mylodontidae, within a sterile deposit of cultural material, dated between ca. 13.500 and 11.200 BP. Despite the fact that it is only a single specimen, such finding extends the known distribution for the genus in Chile.Se presenta la descripción de un I3 asignado a Arctotherium sp. proveniente del sitio Baño Nuevo-1 (Patagonia Central, Chile. El hallazgo fue realizado en la Capa 5 y está asociado a restos de Macrauchenia sp., Lama guanicoe, Felidae, Camelidae, Equidae y Mylodontidae dentro de un depósito estéril de material cultural, datado entre los ca. 13.500 y 11.200 años AP. Aunque se trata de un único espécimen, amplía el rango de distribución conocido para este género en Chile.

  9. Characterization of Baker Fjord region through its heavy metal content on sediments (Central Chilean Patagonia

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    Ramón Ahumada

    2015-07-01

    Full Text Available The spatial distribution of heavy metals content (Ba, Cd, Cu, Pb, Sr and Zn in sediments of the Baker Fjord and surrounding channels in the central region of the Chilean fjords (47°45'S, 48°15'S is analyzed. The aim of the study was characterized the patterns of abundance and distribution of these metals in surface sediments. The area corresponds to a poorly studied zone with low human activity. Distribution patterns would be influenced by rainfall conditions (local erosion, fluvial (continental sediments carried by rivers, glacier (glacier flour and estuarine circulation. Cluster analysis allows differentiation among the sampled sites and group with similar characteristics. Finally, the concentrations found were contrasted with average values of metamorphic rocks and show with some certainty that the values found for calendar for this area and the greatest concentrations are the result of natural enrichment.

  10. Primeros registros de ácaros oribátidos (Acari: Oribatida de bosques de Nothofagus pumilio en la región Patagónica, Chubut, Argentina

    Directory of Open Access Journals (Sweden)

    Erica V. RUIZ

    2015-01-01

    Full Text Available Se informan diecinueve primeros registros de ácaros oribátidos en suelos de bosques de lenga de la provincia de Chubut, Patagonia argentina. Los mismos pertenecen a los géneros Loftacarus, Liochthonius, Sellnickochthonius, Trichthonius, Austrocarabodes, Maculobates, Tectocepheus, Austroppia, Brachioppiella, Pletzenoppia, Globoppia, Lanceoppia, Membranoppia, Graptoppia, Oppiella, Neoameroppia, Subiasella, Suctobelbella y Pheroliodes. Las especies Suctobelbella pseudomatissima y Pheroliodes roblensis se mencionan por primera vez de la Argentina.

  11. Paleomagnetism of Jurassic and Cretaceous rocks in central Patagonia: a key to constrain the timing of rotations during the breakup of southwestern Gondwana?

    Science.gov (United States)

    Geuna, Silvana E.; Somoza, Rubén; Vizán, Haroldo; Figari, Eduardo G.; Rinaldi, Carlos A.

    2000-08-01

    A paleomagnetic study in Jurassic and Cretaceous rocks from the Cañadón Asfalto basin, central Patagonia, indicates the occurrence of about 25-30° clockwise rotation in Upper Jurassic-lowermost Cretaceous rocks, whereas the overlying mid-Cretaceous rocks do not show evidence of rotation. This constrains the tectonic rotation to be related to a major regional unconformity in Patagonia, which in turn seems to be close in time with the early opening of the South Atlantic Ocean. The sense and probably the timing of this rotation are similar to those of other paleomagnetically detected rotations in different areas of southwestern Gondwana, suggesting a possible relationship between these and major tectonic processes related with fragmentation of the supercontinent. On the other hand, the mid-Cretaceous rocks in the region yield a paleopole located at Lat. 87° South, Long. 159° East, A95=3.8°. This pole position is consistent with coeval high-quality paleopoles of other plates when transferred to South American coordinates, implying it is an accurate determination of the Aptian (circa 116 Ma) geomagnetic field in South America.

  12. Using dental enamel wrinkling to define sauropod tooth morphotypes from the Canadon Asfalto Formation, Patagonia, Argentina.

    Directory of Open Access Journals (Sweden)

    Femke M Holwerda

    Full Text Available The early Middle Jurassic is regarded as the period when sauropods diversified and became major components of the terrestrial ecosystems. Not many sites yield sauropod material of this time; however, both cranial and postcranial material of eusauropods have been found in the Cañadón Asfalto Formation (latest Early Jurassic-early Middle Jurassic in Central Patagonia (Argentina, which may help to shed light on the early evolution of eusauropods. These eusauropod remains include teeth associated with cranial and mandibular material as well as isolated teeth found at different localities. In this study, an assemblage of sauropod teeth from the Cañadón Asfalto Formation found in four different localities in the area of Cerro Condor (Chubut, Argentina is used as a mean of assessing sauropod species diversity at these sites. By using dental enamel wrinkling, primarily based on the shape and orientation of grooves and crests of this wrinkling, we define and describe three different morphotypes. With the exception of one taxon, for which no cranial material is currently known, these morphotypes match the local eusauropod diversity as assessed based on postcranial material. Morphotype I is tentatively assigned to Patagosaurus, whereas morphotypes II and III correspond to new taxa, which are also distinguished by associated postcranial material. This study thus shows that enamel wrinkling can be used as a tool in assessing sauropod diversity.

  13. Using dental enamel wrinkling to define sauropod tooth morphotypes from the Cañadón Asfalto Formation, Patagonia, Argentina.

    Science.gov (United States)

    Holwerda, Femke M; Pol, Diego; Rauhut, Oliver W M

    2015-01-01

    The early Middle Jurassic is regarded as the period when sauropods diversified and became major components of the terrestrial ecosystems. Not many sites yield sauropod material of this time; however, both cranial and postcranial material of eusauropods have been found in the Cañadón Asfalto Formation (latest Early Jurassic-early Middle Jurassic) in Central Patagonia (Argentina), which may help to shed light on the early evolution of eusauropods. These eusauropod remains include teeth associated with cranial and mandibular material as well as isolated teeth found at different localities. In this study, an assemblage of sauropod teeth from the Cañadón Asfalto Formation found in four different localities in the area of Cerro Condor (Chubut, Argentina) is used as a mean of assessing sauropod species diversity at these sites. By using dental enamel wrinkling, primarily based on the shape and orientation of grooves and crests of this wrinkling, we define and describe three different morphotypes. With the exception of one taxon, for which no cranial material is currently known, these morphotypes match the local eusauropod diversity as assessed based on postcranial material. Morphotype I is tentatively assigned to Patagosaurus, whereas morphotypes II and III correspond to new taxa, which are also distinguished by associated postcranial material. This study thus shows that enamel wrinkling can be used as a tool in assessing sauropod diversity.

  14. Arte rupestre de Campo Cretton, Piedra Parada, Chubut

    OpenAIRE

    Onetto, María

    1982-01-01

    Este trabajo forma parte de las investigaciones que se lleva a cabo desde enero de 1979 como parte de Proyecto de Rescate del Patrimonio Arqueológico de la Provincia del Chubut –zona del Río Chubut Medio-. Dicho proyecto es auspiciado por el Departamento de Investigaciones de la Dirección de Cultura de la provincia, cuyo director es el licenciado Raúl Scandroglio, con el asesoramiento científico del Dr. Rodolfo Casamiquela. El equipo de trabajo –del cual formo parte- está dirigido por el lice...

  15. La roca de caja del Batolito de la Patagonia Central en Gastre: nuevas evidencias sobre la deformación del Triásico tardío - Jurásico temprano en la región

    Directory of Open Access Journals (Sweden)

    Claudia Beatriz Zaffarana

    2012-03-01

    Full Text Available El hallazgo de dos pequeños afloramientos de esquistos biotítico-anfibólicos y de anfibolitas en dos localidades sugiere que la Formación Cushamen es roca de caja del Batolito de la Patagonia Central en Gastre. Las características de estas rocas metamórficas fueron analizadas mediante estudios petrográficos, microestructurales, de fábrica magnética y de zonación química de granates. Los resultados indican que el granate es producto tardío de metamorfismo de contacto. Los datos estructurales en las localidades estudiadas y en otras áreas de la región no condicen con los modelos de deformación homogénea de transcurrencia dextral propuestos para el sistema de Fallas de Gastre durante el Mesozoico. En cambio, los datos sugieren que la deformación en estado sólido que muestran los granitoides es local y heterogénea, y con posible edad triásica tardía. Nosotros relacionamos esta deformación de baja temperatura con el acomodamiento de los sucesivos pulsos magmáticos que construyeron el Batolito de la Patagonia Central.

  16. Movilidad Espacial, Ocupación y Empleo en el Valle Inferior del Río Chubut Spatial mobility, Occupation and Employment in the Inferior Valley of the River Chubut

    Directory of Open Access Journals (Sweden)

    M. Marcela Crovetto

    2011-12-01

    Full Text Available Desde una perspectiva que propone una serie de críticas a la tipología dicotómica de clasificación demográfica del espacio habitado, rural y urbano, se ha indagado sobre las formas que adquiere la movilidad espacial cotidiana en relación al empleo y a la ocupación en el Valle Inferior del Río Chubut -patagonia argentina-, atendiendo a una situación especial de movilidad espacial cotidiana como es la referida a la producción de cerezas en el Valle. Se utilizaron fuentes secundarias estadísticas, históricas y documentales en articulación con la construcción de datos primarios mediante relevamientos operados por distintas técnicas. Fundamentalmente se aplicó una encuesta a hogares (200 casos de barrios periféricos de las localidades involucradas en el Valle Inferior del Río Chubut El centro del ejercicio de la investigación estuvo en contraponer los resultados de una encuesta realizada en campo de acuerdo tanto a la clasificación clásica de la zona de residencia (rural o urbana como a una propuesta alternativa para la investigación. Así se evaluaron los matices escondidos dentro de las homogeneizantes ideas de rural y urbano, sintetizadas por la cantidad de habitantes -en Argentina con 2000 o más se considera un espacio urbano, con menos un espacio rural- observándose, especialmente, que muchas trayectorias cotidianas de actores sociales considerados clásicamente urbanos se acercaban mucho a las de los actores de las zonas rurales.From a perspective that proposes a number of criticisms of the dichotomous typology of demographic classification of living space, rural and urban, has inquired about the forms that everyday spatial mobility in relation to employment in the Valle Inferior del Río Chubut - Patagonia-Argentina, following a special situation of everyday spatial mobility as that concerning the production of cherries in the Valley. Were used statistics, historical and documentary in coordination with the construction

  17. Historical Glacier Variations in Southern South America since the Little Ice Age: Examples from Lago Viedma (Southern Patagonia) and Mendoza (Central Andes), Argentina

    Science.gov (United States)

    Nussbaumer, S. U.; Masiokas, M.; Pitte, P.; Berthier, E.; Guerrido, C.; Luckman, B. H.; Villalba, R.

    2013-12-01

    The evaluation of historical information can give valuable insight into past glacier dynamics, especially before the onset of modern measurements. Early photographs and maps depict changes for selected glaciers in southern South America. Within this study, written documents and pictorial historical records (drawings, sketches, engravings, photographs, chronicles, topographic maps) are analysed critically, with a particular focus on two regions: Lago Viedma (El Chaltén, southern Patagonia, 49.5°S, 73.0°W) and the Río Mendoza basin (Mendoza, central Andes, 33.1°S, 69.9°W). For the Lago Viedma area, early historical data for the end of the 19th century stem from the expedition of the Chilean-Argentinean border commission. In addition, the expedition by the German Scientific Society, conducted between 1910 and 1916, and the later photographs by Alberto M. de Agostini give an excellent depiction of the glaciers. Glaciar Viedma is a calving glacier which shows distinct retreat from 1896 until the present (though with a stationary or possibly advancing glacier front between 1930/31 and 1951/52), similar to the neighbouring glaciers. On the contrary, nearby Glaciar Perito Moreno shows an exceptional behaviour: the glacier front has been advancing during the first half of the 20th century, staying in an advanced position until the present. At the beginning of the 20th century, Robert Helbling explored the Argentinean-Chilean Andes together with his friend Friedrich Reichert. In the summer of 1909/10, they started a detailed survey of the highly glacierized Juncal-Tupungato mountains (Río Mendoza basin), leading to the first accurate topographic map of the area published in 1914. Its outstanding quality allows a comparison with contemporary satellite imagery. The area received attention in 1934, when the sudden drainage of a glacier-dammed lake in the upper Río del Plomo valley caused fatalities and considerable damage to constructions and the Transandine Railway. A

  18. Tropical/subtropical Upper Paleocene Lower Eocene fluvial deposits in eastern central Patagonia, Chile (46°45'S)

    Science.gov (United States)

    Suárez, M.; de la Cruz, R.; Troncoso, A.

    2000-11-01

    A succession of quartz-rich fluvial sandstones and siltstones derived from a mainly rhyolitic source and minor metamorphic rocks, located to the west, represent the first Upper Paleocene-Early Eocene deposits described in Chilean eastern central Patagonian Cordillera (46°45'S). This unit, exposed 25 km south of Chile Chico, south of lago General Carrera, is here defined as the Ligorio Márquez Formation. It overlies with an angular unconformity Lower Cretaceous shallow marine sedimentary rocks (Cerro Colorado Formation) and subaerial tuffs that have yielded K-Ar dates of 128, 125 and 123 Ma (Flamencos Tuffs, of the Divisadero Group). The Ligorio Márquez Formation includes flora indicative of a tropical/subtropical climate, and its deposition took place during the initial part of the Late Paleocene-Early Eocene Cenozoic optimum. The underlying Lower Cretaceous units exhibit folding and faulting, implying a pre-Paleocene-Lower Eocene contractional tectonism. Overlying Oligocene-Miocene marine and continental facies in the same area exhibit thrusts and normal faults indicative of post-Lower Miocene contractional tectonism.

  19. Programa provincial de lectura del Chubut

    Directory of Open Access Journals (Sweden)

    Natalia Alejandra Alaniz

    2014-10-01

    Full Text Available En el marco del proyecto “Dispositivos pedagógicos en las dinámicas de lavida escolar en contexto de pobreza urbana” lo que se propuso investigar es la forma de implementación del Programa de Lectura de la provincia de Chubut. El mismo fue creado por Resolución Ministerial N° 1044/ 08, a partir de diversos trabajos que comenzaron en el año 2003 a través de la Ley de Educación 26. 026, y que posteriormente se incorporaron a nivel provincial mediante la Resolución N ° 174/12 para revalorizar las trayectorias escolares de cada niño/a. El programa consiste en poner el énfasis en el vínculo pedagógico mediante la adecuación de los espacios curriculares, de tal modo que se pueda lograr una articulación entre los diferentes niveles educativos, desde el nivel inicial al secundario. Articulando para ello recursos materiales y humanos que posibiliten el acompañamiento del proceso de enseñanza y aprendizaje de lectura.A partir de esto, el objetivo de este trabajo fue indagar cómo perciben los docentes de una escuela pública la implementación del Programa Provincial de Lectura, lo que implico utilizar metodologías y técnicas de investigación apropiadas para obtener las experiencias actuales en el territorio y en la cotidianidad de los propios actores escolares. Teniendo en consideración que el dispositivo pedagógico es una construcción histórica, que produce subjetividades, y por consiguiente formas de ver y entender el mundo.

  20. La Patagonia galesa entre el tablero estatal y la idealización naturalista: aportes desde una perspectiva paisajística

    Directory of Open Access Journals (Sweden)

    Fernando Williams

    2014-11-01

    Full Text Available El presente artículo estudia la apropiación física y simbólica del territoriodesplegada desde la Colonia Chubut, primera colonia agrícola de la Patagonia,fundada en 1865 por un grupo de galeses. El interés del trabajo es la gestióndel territorio puesta en práctica por las instituciones formadas en el valledel Chubut por los colonos, en particular, por el “Municipio del Chubut” consede en Gaiman. Se han problematizado las coordenadas desde las que eraconcebido lo político y lo público y se ha incorporado al análisis un conjuntode registros que dan cuenta de una gestión informada no sólo por una legislaciónsino también por las prácticas y las miradas sobre ese territorio.

  1. Patagonia: nature and territories

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    Alejandro Fabián Schweitzer

    2014-12-01

    This paper analyzes the place occupied by Patagonia in today’s fin de siècle scenario of commodities, hegemony crisis and multi-polar world emergence concurring with the convergence of consumerist guidelines, all of which would apparently lead to an in-depth socio-ecological crisis as well as to an accelerated dispute over nature and territory sense.

  2. Agua, Poder y Discursos: Conflictos Socio-territoriales por la construcción de centrales hidroeléctricas en la Patagonia Chilena

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    Romero Toledo, Hugo

    2009-12-01

    Full Text Available Chile is going to celebrate soon two hundred years of republican life and thirty five years of the application of a neoliberal economic model, in respect of which there are a lot of conflicts related with the land/capital dicotomy and water like a main resource. One of these conflicts is currently taking place in Chilean Patagonia, where, as a direct result of water privatization, a large hydropower project, supported by transnational companies collisions with traditional production and highly environmental quality landscapes.

    Chile está próximo a celebrar su Bicentenario de vida republicana y sus treinta y cinco años desde la aplicación de un estricto modelo económico neoliberal, donde han surgido numerosos conflictos que involucran a la dicotomía capital/territorio y que implican al agua como recurso principal. Uno de estos conflictos es el que actualmente ocurre en la Región de Aysén en la Patagonia Chilena donde, producto de la privatización del agua, un megaproyecto de producción hidroeléctrica de inversión transnacional colisiona con territorios de alta calidad ambiental y producción tradicional.

  3. Influencia de Especies Arbóreas Implantadas sobre Parámetros Biológicos y Bioquímicos en un Suelo Forestal de Chubut, Argentina Influence of Implanted tree Species on Biological and Biochemical Parameters in a Forest soil of Chubut, Argentina

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    Diana N Effron

    2012-01-01

    Full Text Available Se estudió la influencia de algunas especies forestales sobre propiedades biológicas y bioquímicas de un suelo, con el propósito de contribuir a establecer criterios que logren un desarrollo sustentable para un sistema forestal. El sitio de estudio es un suelo forestal de Chubut, en la Patagonia Argentina. Se tomaron muestras superficiales de suelo de tres parcelas con una especie dominante cada una: Roble (Quercus robur, Fresno (Fraxinus excelsior L. y Pino radiata (Pinus radiata D. Don.. En ellas se determinaron carbono de respiración, actividad deshidrogenasa, actividad fosfatasa ácida, número de bacterias totales y amilolíticas, actinomicetes y hongos totales, mientras que en las hojas se determinó fósforo. Los resultados mostraron diferencias importantes de estos parámetros para las diferentes especies estudiadas, diferencias que son explicadas por la composición química de las diferentes especies vegetales.The influence of some tree species on biological and biochemical properties of a forest soil was studied with the purpose of establishing criteria to achieve a sustainable development of a forest system. The study site is a forest soil of Chubut, in the Argentinean Patagonia. Surface soil samples were taken of three plots with a dominant species each one: Oak (Quercus robur, Ash (Fraxinus excelsior L. and Radiata Pine (Pinus radiata D. Don.. Microbial respiration, dehydrogenase and acid phosphatase activities, counts of aerobic and amylolytic bacteria, actinomyces and fungi were determined in soil samples, while phosphorous was determines in leaves. The results showed important differences of these parameters for the different species considered in the study, differences that are explained by the different chemical composition of the vegetal species.

  4. Analysis of admixture and genetic structure of two Native American groups of Southern Argentinean Patagonia.

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    Sala, Andrea; Corach, Daniel

    2014-03-01

    Argentinean Patagonia is inhabited by people that live principally in urban areas and by small isolated groups of individuals that belong to indigenous aboriginal groups; this territory exhibits the lowest population density of the country. Mapuche and Tehuelche (Mapudungun linguistic branch), are the only extant Native American groups that inhabit the Argentinean Patagonian provinces of Río Negro and Chubut. Fifteen autosomal STRs, 17 Y-STRs, mtDNA full length control region sequence and two sets of Y and mtDNA-coding region SNPs were analyzed in a set of 434 unrelated individuals. The sample set included two aboriginal groups, a group of individuals whose family name included Native American linguistic root and urban samples from Chubut, Río Negro and Buenos Aires provinces of Argentina. Specific Y Amerindian haplogroup Q1 was found in 87.5% in Mapuche and 58.82% in Tehuelche, while the Amerindian mtDNA haplogroups were present in all the aboriginal sample contributors investigated. Admixture analysis performed by means of autosomal and Y-STRs showed the highest degree of admixture in individuals carrying Mapuche surnames, followed by urban populations, and finally by isolated Native American populations as less degree of admixture. The study provided novel genetic information about the Mapuche and Tehuelche people and allowed us to establish a genetic correlation among individuals with Mapudungun surnames that demonstrates not only a linguistic but also a genetic relationship to the isolated aboriginal communities, representing a suitable proxy indicator for assessing genealogical background.

  5. Extensive sheep production in the Austral Patagonia: the case of Santa Cruz central zone Producción ovina extensiva en la Patagonia Austral: El caso de la zona centro de Santa Cruz

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    Larry Andrade

    2010-01-01

    Full Text Available The intention of the article is to analyze the central plateau of Santa Cruz in its socio-productive aspects. The main aim of the investigation, from which this work is a partial elaboration, is to establish: on the one hand, the viability of the traditional extensive ovine model in the region; on the other hand, the possibilities that the associative practices have to become the articulador axis of a productive relaunching. Here, we present a first socioeconomic and productive analysis in order to define the scene in which, at the moment, the extensive ovine production takes ahead. We include a description of the new actors who, nowadays, operate in the area of study, standing out among them, the transnational mining companies.El propósito del artículo consiste en analizar la meseta central de Santa Cruz en sus aspectos socioproductivos. El objetivo de la investigación, de la cual este trabajo es una elaboración parcial, se orienta a establecer la viabilidad del modelo vigente en la región -ovino extensivo-, así como las posibilidades de que las prácticas asociativas se constituyan en el eje articulador de un relanzamiento productivo. Aquí presentamos un primer análisis socioeconómico y productivo con la finalidad de definir el escenario en el que actualmente se lleva adelante la producción ovina extensiva. Incluimos una descripción de los nuevos actores que actualmente operan en el centro-norte de la provincia y, especialmente en nuestra área de estudio, destacándose entre ellos las empresas mineras transnacionales.

  6. Territorio y ganadería en la Patagonia Argentina: desertificación y rentabilidad en la Meseta Central de Santa Cruz

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    Larry Andrade

    2002-01-01

    Full Text Available El artículo revisa brevemente las características que asume el proceso de desertificación en la Patagonia Austral, con énfasis en la provincia de Santa Cruz, Argentina. Se hacen referencias a la ocupación del territorio santacruceño por el ganado ovino, a fines del siglo XIX y con más intensidad a principios del siglo XX, y el impacto que ello conllevó, especialmente el desencadenamiento de un proceso erosivo (desertificación, producido básicamente por el pastoreo constante (sobrepastoreo del pastizal natural. También se encuentran referencias al sector ganadero y su participación en el producto bruto geográfico (PBG de Santa Cruz y, hacia el final, un análisis comparativo de la cantidad de animales que el productor estima que puede sostener en su campo y la cantidad que el Instituto Nacional de Tecnología Agropecuaria (INTA, con base en relevamientos de pastizal, calcula que podría mantener.

  7. Primer estudio de artropodofauna cadavérica sobre modelos experimentales porcinos en el noreste de la provincia del Chubut, Argentina

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    Ana P. ARMANI

    2015-01-01

    Full Text Available En este trabajo se estudió el proceso de descomposición y la composición de insectos presentes en biomodelos porcinos, en el NE de la provincia del Chubut. El objetivo fue determinar la composición específica, abundancia y riqueza de la artropodofauna carroñera en el ambiente de estepa. Se realizaron muestreos estacionales durante tres años consecutivos utilizándose tres cerdos domésticos para cada muestreo, colocados dentro de jaulas de madera cubiertas de alambre tejido. Diariamente se colectaron los artrópodos en el cuerpo, debajo y alrededor de este. Se registraron 36.157 individuos pertenecientes a 78 especies de 18 familias distribuidas entre los órdenes Diptera, Coleoptera e Hymenoptera. Se citan por primera vez de la provincia de Chubut tres especies de Calliphoridae: Paralucilia pseudolyrcea Mello, Paralucilia fulvinota Bigot y Chrysomya albiceps Wiedemann; y una especie de Muscidae: Arthurella choelensis Patitucci & Mariluis. Se incorpora como primera cita para la fauna cadavérica argentina a Sarcophaga (Lipoptilocnema margaretae Lahille (Sarcophagidae. Se trata del primer estudio sobre entomología forense realizado en Patagonia que permite conocer los procesos de descomposición cadavérica y la fauna de insectos carroñeros presentes en esta zona. Por lo tanto, aporta información relevante que puede utilizarse en la resolución de casos forenses humanos en la región.

  8. Subduction of the South Chile active spreading ridge: A 17 Ma to 3 Ma magmatic record in central Patagonia (western edge of Meseta del Lago Buenos Aires, Argentina)

    Science.gov (United States)

    Boutonnet, E.; Arnaud, N.; Guivel, C.; Lagabrielle, Y.; Scalabrino, B.; Espinoza, F.

    2010-01-01

    The Chile Triple Junction is a natural laboratory to study the interactions between magmatism and tectonics during the subduction of an active spreading ridge beneath a continent. The MLBA plateau (Meseta del Lago Buenos Aires) is one of the Neogene alkali basaltic plateaus located in the back-arc region of the Andean Cordillera at the latitude of the current Chile Triple Junction. The genesis of MLBA can be related with successive opening of slabs windows beneath Patagonia: within the subducting Nazca Plate itself and between the Nazca and Antarctic plates. Detailed 40Ar/ 39Ar dating and geochemical analysis of bimodal magmatism from the western flank of the MLBA show major changes in the back-arc magmatism which occurred between 14.5 Ma and 12.5 Ma with the transition from calc-alkaline lavas (Cerro Plomo) to alkaline lavas (MLBA) in relation with slab window opening. In a second step, at 4-3 Ma, alkaline felsic intrusions were emplaced in the western flank of the MLBA coevally with the MLBA basalts with which they are genetically related. These late OIB-like alkaline to transitional basalts were generated by partial melting of the subslab asthenosphere of the subducting Nazca plate during the opening of the South Chile spreading ridge-related slab window. These basalts differentiated with small amounts of assimilation in shallow magma chambers emplaced along transtensional to extensional zones. The close association of bimodal magmatism with extensional tectonic features in the western MLBA is a strong support to the model of Patagonian collapse event proposed to have taken place between 5 and 3 Ma as a consequence of the presence of the asthenospheric window (SCR-1 segment of South Chile Ridge) below the MLBA area.

  9. Estratigrafía y petrología del sector noreste de sierra de Apas. Provincia del Chubut Stratigraphy and petrology of the Northeastern sector of Sierra de Apas. Chubut Province

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    M. Remesal

    2004-12-01

    Full Text Available La sierra de Apas, ubicada entre las provincias de Rio Negro y Chubut, forma parte del magmatismo de intraplaca emplazado durante el Paleogeno-Neógeno en el norte de la Patagonia extrandina. En el sector noreste se ha definido una estratigrafía integrada por: traquitas oscuras, flujos piroclásticos, traquitas claras, domos riolíticos y basaltos porfíricos y afíricos. Las traquitas oscuras, son relativamente más antiguas, tienen bajo porcentaje de fenocristales, y clasifican como traquitas- benmoreítas. Las traquitas claras son porfíricas, y clasifican como comenditas. Su ubicación estratigráfica es confirmada por una edad K/Ar de 19 ± 2 Ma. Los flujos piroclásticos son predominantemente vítreos, cubren a las traquitas oscuras y tienen composiciones traquiandesíticas. La petrografía y geoquímica establecen una estrecha relación con las traquitas claras. El único cuerpo dómico en el área es el cerro Colorado, cuya composición corresponde a una riolita peralcalina ó comendita; una edad K/Ar de 24 ± 1 Ma establece por primera vez su relación temporal. La unidad efusiva más joven corresponde a lavas basálticas, agrupadas en afíricas y porfíricas. Se propone designar a las primeras como basaltos olivínicos transicionales en tanto que los basaltos porfíricos se subdividen en basaltos olivínicos alcalinos y hawaiitas. Los datos estratigráficos y geoquímicos sugieren que la asociación volcánica estudiada es el resultado de al menos dos etapas evolutivas. Una de ellas incluye los basaltos, traquitas claras, flujos claros y comenditas que muestran un patrón de cristalización fraccionada. Las traquitas oscuras, más viejas, corresponderían a otro estadio evolutivo.The volcanic building of Sierra de Apas (located on the limit between the Rio Negro and Chubut provinces is part of the Paleogene-Neogene intraplate magmatism of the northern Extrandean Patagonia. This contribution is focused on the northeastern of the Sierra

  10. Primer registro de diplostomiasis ocular en trucha arco iris cultivada en Patagonia (Argentina First record of diplostomiasis in cultured rainbow trout in Patagonia (Argentina

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    L. SEMENAS

    1998-01-01

    Full Text Available Se describe por primera vez para la Patagonia argentina un caso de diplostomiasisocular o catarata verminosa en peces de un establecimiento de críaen estanques en la provincia de Chubut. Para el diagnóstico se analizaroncaracoles (Chilina dombeiana por técnica de aplastamiento y truchasarco iris (Oncorhynchus mykiss por técnica de necropsia con microdisecciónde ojos. El hallazgo de esporocistos de Diplostomidae en el hepatopáncreasde los caracoles y de metacercarias de Diplostomum sp. en los cristalinosde los peces, permitió diagnosticar que la catarata era de origenparasitario. Se detallan las recomendaciones dadas para el control y laprevención de la enfermedad, basadas en métodos ecológicosteniendo en cuenta fundamentalmente el ciclo del parásito y lascaracterísticas de las instalaciones de la piscicultura. Este trabajoamplía la distribución de esta enfermedad en trucha arcoiris cultivada hasta el sur de ArgentinaA case of ocular diplostomiasis (parasite cataract in fish or eyefluke disease is described for the first time in a pisciculture with earth ponds in the province of Chubut. Snails (Chilina dombeiana were analysed by squashing and rainbow trout (Oncorhynchus mykiss by necropsy with microdissection of eyes, for the diagnosis. The findings of sporocysts of Diplostomidae in the hepatopancreas of snails and metacercariae of Diplostomum sp. in the lens of fish confirm the cataract as parasitic. Detailed recommendations for the control and prevention of the disease, based mainly on ecological methods, taking into account the cycle of the parasite and the characteristics of the building of the pisciculture are given. This paper amplifies the distribution of this disease in cultured rainbow trout, including the southern part of South America

  11. Petrological features of suprasubuction mantle: evidence from northern, central and southern Patagonian mantle xenoliths

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    Melchiorre, M.; Coltorti, M.; Gregoire, M.; Benoit, M.

    2012-04-01

    Patagonia has a number of outcrops where xenoliths-bearing lavas can be found. It thus represents a good opportunity to study mantle material in supra-subduction environment both on arc and back-arc position, from as near as 300 km to as far as 600 km from the Chile trench. A wealth of data is nowadays available on these xenoliths, starting from petrographic observations, whole-rock and mineral major and trace element analyses plus few isotopic analyses on whole rock and mineral separates. To this already large dataset the petrological features of another locality (Estancia Sol de Mayo, ESM) were added, allowing a comparison between as much as eight localities coming from northern (Cerro Aznare, Praguaniyeu, Cerro Rio Chubut, Cerro de los Chenques), central (Cerro Clark and Gobernador Gregores) and southern Patagonia (Pali Aike), covering approximately an area of 1000 x 300 km. Most xenoliths are harzburgites, with minor amount of lherzolites, wehrlites and dunites. In the Al2O3 vs mg# [MgO/(MgO+FeO) mol %] diagram clinopyroxene (cpx) compositions highlight three different trends, with orthopyroxene (opx) compositions plotting on two of these. In the first trend Al2O3 content increases at almost constant mg# mol % (trend 1). The second trend comprises only cpx from wehrlites (trend 2) and is situated between the first and the third trend. In the third trend the slight increases of Al2O3 is associated with a remarkable decrease in mg# (trend 3). LREE and LILE abundances in cpx from Tres Lagos and Cerro Rio Chubut are directly correlated to the Al2O3, while they are inversely correlated at Cerro de Los Chenques and Cerro Fraile. In the first case it is likely that a metasomatic process affects the mantle domains beneath those areas, while in the second case a refertilization event caused by a tholeiitic melt is favorite. In other cases, as for Gobernador Gregores, a more complex situation is recorded, with two groups of samples showing both negative and positive

  12. A Tenebrionid beetle’s dataset (Coleoptera, Tenebrionidae from Peninsula Valdés (Chubut, Argentina

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    German Cheli

    2013-12-01

    Full Text Available The Natural Protected Area Peninsula Valdés, located in Northeastern Patagonia, is one of the largest conservation units of arid lands in Argentina. Although this area has been in the UNESCO World Heritage List since 1999, it has been continually exposed to sheep grazing and cattle farming for more than a century which have had a negative impact on the local environment. Our aim is to describe the first dataset of tenebrionid beetle species living in Peninsula Valdés and their relationship to sheep grazing. The dataset contains 118 records on 11 species and 198 adult individuals collected. Beetles were collected using pitfall traps in the two major environmental units of Peninsula Valdés, taking into account grazing intensities over a three year time frame from 2005–2007. The Data quality was enhanced following the best practices suggested in the literature during the digitalization and geo-referencing processes. Moreover, identification of specimens and current accurate spelling of scientific names were reviewed. Finally, post-validation processes using DarwinTest software were applied. Specimens have been deposited at Entomological Collection of the Centro Nacional Patagónico (CENPAT-CONICET. The dataset is part of the database of this collection and has been published on the internet through GBIF Integrated Publishing Toolkit (IPT (http://data.gbif.org/datasets/resource/14669/. Furthermore, it is the first dataset for tenebrionid beetles of arid Patagonia available in GBIF database, and it is the first one based on a previously designed and standardized sampling to assess the interaction between these beetles and grazing in the area. The main purposes of this dataset are to ensure accessibility to data associated with Tenebrionidae specimens from Peninsula Valdés (Chubut, Argentina, also to contribute to GBIF with primary data about Patagonian tenebrionids and finally, to promote the Entomological Collection of Centro Nacional Patag

  13. Doble difusión a partir de mediciones de microestructura en los canales Martínez y Baker, Patagonia chilena central (47,85°S

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    Iván Pérez-Santos

    2013-03-01

    Full Text Available Con un microperfilador SCAMP (Self Contained Autonomous MicroProfile se detectó un proceso de Doble Difusión Convectiva (DDC, en los canales Martínez y Baker de la Patagonia central, Chile. Este perfilador midió temperatura y salinidad en la columna de agua con una resolución del orden de milímetros. El muestreo se efectuó en diciembre 2011, en 19 estaciones oceanográficas de ~55 m de profundidad. Los registros del microperfilador permitieron detectar la formación de escaleras termohalinas que caracterizan la formación de la DDC. Por medio del ángulo de Turner se confirmó que debajo de una capa superficial fuertemente estratificada (7-10 m se registraron eventos de DDC a profundidades entre 15 y 45 m. La DDC fue débil en la mayoría de los registros pero se evidenciaron eventos fuertes entre 15 y 40 m. En la capa subsuperficial, su origen se debió al intercalamiento de las masas aguas estuarinas (aguas frías y menos saladas encima de las oceánicas (aguas más cálidas y saladas, mientras que en la superficie la interacción océano-atmósfera favoreció su ocurrencia. La DDC en conjunto con el viento, las mareas y las ondas internas, puede constituir un mecanismo importante para la mezcla vertical, influenciando los flujos de calor, el hábitat de las especies marinas en estas profundidades y la exportación de carbono hacia los sedimentos.

  14. Paleontology, sedimentology and paleoenvironment of a new fossiliferous locality of the Jurassic Cañadón Asfalto Formation, Chubut Province, Argentina

    Science.gov (United States)

    Gallego, Oscar F.; Cabaleri, Nora G.; Armella, Claudia; Volkheimer, Wolfgang; Ballent, Sara C.; Martínez, Sergio; Monferran, Mateo D.; Silva Nieto, Diego G.; Páez, Manuel A.

    2011-02-01

    A new Late Jurassic assemblage of “conchostracans”, ostracods, bivalves and caddisfly cases from the locality “Estancia La Sin Rumbo”, Chubut Province (Patagonia, Argentina) is recorded. The fossils occur in the upper part of an outcropping 45 m thick volcaniclastic lacustrine sequence of yellowish tuffs and tuffites of the Puesto Almada Member, which is the upper member of the Cañadón Asfalto Formation with U/Pb age of 161 ± 3 Ma. The sequence represents one sedimentary cycle composed of a (lower) hemicycle of expansion and a (higher) hemicycle of contraction of the water body. The invertebrates lived in small freshwater bodies during the periods of expansion of the lake. The occurrence of a great number of small spinicaudatans, associated with mud-cracks, is evidence of dry climatic conditions and suggests several local mortality events. The spinicaudatan record of the fushunograptid-orthestheriid (component of the Eosestheriopsis dianzhongensis fauna) and the presence of Congestheriella rauhuti Gallego and Shen, suggest a Late Jurassic (Oxfordian to Tithonian) age. Caddisfly cases are recorded for the first time in the Cañadón Asfalto Basin.

  15. Monitoreo ambiental de aguas superficiales y subterráneas, consideración de áreas sensibles, distrito uranífero Pichiñán Este, departamento Paso de Indios, provincia del Chubut

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    Humberto O Nievas

    2013-09-01

    Full Text Available En el ámbito de los estudios ambientales los sitios de localización de pobladores son considerados como áreas sensibles frente a una posible explotación del recurso uranífero. Se analiza la hidroquímica de los alrededores del distrito uranífero Pichiñán Este, sector central de la provincia del Chubut, por medio de un monitoreo que, desde el 2007, se realiza aplicando la metodología de muestreo de la comunidad europea. Se caracteriza la calidad del agua considerando elementos mayoritarios, minoritarios y trazas, estableciendo de esta manera sus potenciales usos. Estos resultados son informados a los pobladores y a la autoridad de control ambiental de la provincia del Chubut. Aunque, en general, la calidad del agua en cada punto de muestreo se mantiene relativamente constante, se observan variaciones naturales en los contenidos químicos.

  16. La roca de caja del Batolito de la Patagonia Central en Gastre: nuevas evidencias sobre la deformación del Triásico tardío - Jurásico temprano en la región The Host Rock Of The Central Patagonian Batholith In Gastre: Further Insights On The Late Triassic To Early Jurassic Deformation In The Region

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    Claudia Beatriz Zaffarana

    2012-03-01

    Full Text Available El hallazgo de dos pequeños afloramientos de esquistos biotítico-anfibólicos y de anfibolitas en dos localidades sugiere que la Formación Cushamen es roca de caja del Batolito de la Patagonia Central en Gastre. Las características de estas rocas metamórficas fueron analizadas mediante estudios petrográficos, microestructurales, de fábrica magnética y de zonación química de granates. Los resultados indican que el granate es producto tardío de metamorfismo de contacto. Los datos estructurales en las localidades estudiadas y en otras áreas de la región no condicen con los modelos de deformación homogénea de transcurrencia dextral propuestos para el sistema de Fallas de Gastre durante el Mesozoico. En cambio, los datos sugieren que la deformación en estado sólido que muestran los granitoides es local y heterogénea, y con posible edad triásica tardía. Nosotros relacionamos esta deformación de baja temperatura con el acomodamiento de los sucesivos pulsos magmáticos que construyeron el Batolito de la Patagonia Central.Small outcrops of biotitic-amphibolic schists and amphibolites found in two localities suggest that the Cushamen Formation is host rock of the Central Patagonian Batholith in Gastre. The characteristics of these rocks were investigated using structural, petrographic, magnetic fabric, and garnet chemicalzonation studies. Garnet is observed as a late product of contact metamorphism. Structural data from the studied area and from other localities in the region are in conflict with models that invoke the occurrence of uniform, large-scale dextral displacements along the Gastre lineament in Mesosoic times. Rather, the data suggest that the Gastre granitoids record heterogeneous low-temperature deformation of likely Late Triassic age. This low-temperature deformation appears as small, localized outcrops, and we suggest that it is related to the accommodation of the successive magma batches that built the Central

  17. Geophysical characterization of circular structures in Chubut and Mendoza (Argentina): Impact vs. Volcanism

    Science.gov (United States)

    Prezzi, C.; Orgeira, M. J.; Risso, C.; Acevedo, R.; Ponce, F.; Nullo, F.; Martinez, O.; Rabassa, J.; Margonari, L.; Corbella, H.

    2013-05-01

    This work focuses on two main objectives. One of them is to provide information to discern the genesis of the circular structures present in Bajada del Diablo (Chubut, Argentina) considered as impact craters, and the other one is to contribute to a better knowledge of the circular structures located in the volcanic fields of Llancanelo and Payunia (Mendoza, Argentina). Chubut circular structures have been attributed to the collision of an extraterrestrial body, possibly an asteroid. However, doubts persist about their genesis because of the lack of direct geological evidences. Since detailed geomorphological studies have ruled out an origin by wind deflation, the prevailing alternative hypothesis attributes these circular structures to a volcanic process. On the other hand, the study of the volcanic fields of Payunia and Llancanelo (Mendoza) will contribute to the knowledge of the mechanics of hydromagmatic processes in the area, and the origin of circular structures morphologically similar to those located in Chubut. In the Payunia volcanic field at least 27 cones with evidences of hydromagmatism, in a field of more than 800 pure magmatic cones, have been recognized. This study tries to determine if a relationship between the observed volcanic circular structures and participation of water during the eruption exists. Magnetic and gravity field surveys of the circular volcanic structures in Llancanelo and Payunia volcanic fields were performed in order to determine their relationship with the type of eruption. Electromagnetic, magnetic and gravity field surveys were also carried out in Chubut circular structures. The comparative analysis of geological and geophysical results obtained in the circular structures of Chubut and those obtained in the circular structures in the volcanic areas of Llancanelo and Payunia suggest an impact origin for the circular structures of Chubut.

  18. Petrogénesis de los thundereggs en domos riolíticos del centro del Chubut, Patagonia

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    E. Aragón

    2006-09-01

    Full Text Available Se describen los thundereggs que se encuentran en domos vitrofíricos de la caldera de Piedra Parada. Tanto las características geológicas, petrológicas como geoquímicas sugieren que estos crecen a partir de gotas de líquidos inmiscibles que se desvitrificaron como esferulitas de anortoclasa. La expansión de la fase vapor segregada al desvitrificarse las gotas inmiscibles, rompieron las esferulitas y desarrollaron grandes vesículas tapizadas por los pedazos rotos de la esferulita. El inmediato enfriamiento del resto del magma dio lugar a la formación de un domo vítreo con textura perlítica. Posteriormente, agua a baja temperatura lixivió al vidrio esferulítico y rellenó las cavidades de las vesículas y esferulitas con ópalo y/o calcedonia.

  19. Petrogénesis de los thundereggs en domos riolíticos del centro del Chubut, Patagonia

    OpenAIRE

    E. Aragón; J.A. Saadi; M.C. Ubaldón; A.M. Kuck; C.E. Cavarozzi; Y.E. Aguilera; A. Ribot; González, S

    2006-01-01

    Se describen los thundereggs que se encuentran en domos vitrofíricos de la caldera de Piedra Parada. Tanto las características geológicas, petrológicas como geoquímicas sugieren que estos crecen a partir de gotas de líquidos inmiscibles que se desvitrificaron como esferulitas de anortoclasa. La expansión de la fase vapor segregada al desvitrificarse las gotas inmiscibles, rompieron las esferulitas y desarrollaron grandes vesículas tapizadas por los pedazos rotos de la esferulita. El inmediato...

  20. Extraterrestrial microspherules from Bajada del Diablo, Chubut, Argentina

    Directory of Open Access Journals (Sweden)

    M.J. Orgeira

    2017-01-01

    Full Text Available The Quaternary infilling of a circular structure located in Bajada del Diablo, Chubut Province, Argentina has been proposed as a crater strewn field in previous studies. Here we report the finding of about 65 microspherules collected in a trench excavated in the center of the structure. The majority of hand-picked specimens are single, but some of them exhibit compound forms. The single specimens are spherical with a mean size of 137 μm, whereas the more complex samples show peduncles and drop shapes. Dendritic crystal growth is recognized in the internal structure of some broken microspherules. Preliminary chemical composition from the surface and center of microspherules was determined by energy dispersive spectrometry employing EDS. Quantitative EMPA and XRD analysis indicate that the microspherules are mainly composed of Fe and O with magnetite, Fe0 with subordinate wüstite. Following consideration of possible anthropogenic and volcanic origins, these spherulites are ascribed to an extraterrestrial input. An accumulation rate of 47 microspherules per m2/yr is estimated for the studied sediments. This value is two orders of magnitude higher than the reference flux for cosmic dust estimated for the last 1 Ma in the Transantarctic Mountains. The microspherules might have been generated as a byproduct of asteroid entry in the atmosphere.

  1. Anaglyph: Patagonia, Argentina

    Science.gov (United States)

    2000-01-01

    This view of northern Patagonia, near El Cain, Argentina shows complexly eroded volcanic terrain, with basalt mesas, sinkholes, landslide debris, playas, and relatively few integrated drainage channels. Surrounding this site (but also extending far to the east) is a broad plateau capped by basalt, the Meseta de Somuncura. Here, near the western edge of the plateau, erosion has broken through the basalt cap in a variety of ways. On the mesas, water-filled sinkholes (lower left) are most likely the result of the collapse of old lava tubes. Along the edges of the mesas (several locations) the basalt seems to be sliding away from the plateau in a series of slices. Water erosion by overland flow is also evident, particularly in canyons where vegetation blankets the drainage channels (bright patterns, bottom of image). However, overland water flow does not extend very far at any location. This entire site drains to local playas, some of which are seen here (dark lakes with bright shores). While the water can reach the playas and then evaporate, what becomes of the eroded rock debris? Wind might excavate some of the finer eroded debris, but the fate of much of the missing bedrock remains mysterious.This anaglyph was generated by first draping a Landsat Thematic Mapper image over a topographic map from the Shuttle Radar Topography Mission, then producing the two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and the right eye with a blue filter.Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to

  2. Stereo Pair: Patagonia, Argentina

    Science.gov (United States)

    2000-01-01

    This view of northern Patagonia, near El Cain, Argentina shows complexly eroded volcanic terrain, with basalt mesas, sinkholes, landslide debris, playas, and relatively few integrated drainage channels. Surrounding this site (but also extending far to the east) is a broad plateau capped by basalt, the Meseta de Somuncura. Here, near the western edge of the plateau, erosion has broken through the basalt cap in a variety of ways. On the mesas, water-filled sinkholes (lower left) are most likely the result of the collapse of old lava tubes. Along the edges of the mesas (several locations) the basalt seems to be sliding away from the plateau in a series of slices. Water erosion by overland flow is also evident, particularly in canyons where vegetation blankets the drainage channels (green patterns, bottom of image). However, overland water flow does not extend very far at any location. This entire site drains to local playas, some of which are seen here (blue). While the water can reach the playas and then evaporate, what becomes of the eroded rock debris? Wind might excavate some of the finer eroded debris, but the fate of much of the missing bedrock remains mysterious.This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced Landsat 7 satellite color image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7

  3. Relationship between volcanism and marine sedimentation in northern Austral (Aisén) Basin, central Patagonia: Stratigraphic, U-Pb SHRIMP and paleontologic evidence

    Science.gov (United States)

    Suárez, M.; De La Cruz, R.; Aguirre-Urreta, B.; Fanning, M.

    2009-04-01

    The northernmost part of the oil-producing Austral Basin, known as Aisén Basin or Río Mayo Embayment (in central Patagonian Cordillera; 43-46°S), is a special area within the basin where the interplay between volcanism and the initial stages of its development can be established. Stratigraphic, paleontologic and five new U-Pb SHRIMP age determinations presented here indicate that the Aisén Basin was synchronous with the later phases of volcanism of the Ibáñez Formation for at least 11 m.yr. during the Tithonian to early Hauterivian. In this basin marine sedimentary rocks of the basal units of the Coihaique Group accumulated overlying and interfingering with the Ibáñez Formation, which represents the youngest episode of volcanism of a mainly Jurassic acid large igneous province (Chon Aike Province). Five new U-Pb SHRIMP magmatic ages ranging between 140.3 ± 1.0 and 136.1 ± 1.6 Ma (early Valanginian to early Hauterivian) were obtained from the Ibáñez Formation whilst ammonites from the overlying and interfingering Toqui Formation, the basal unit of the Coihaique Group, indicate Tithonian, early Berriasian and late Berriasian ages. The latter was a synvolcanic shallow marine facies accumulated in an intra-arc setting, subsequently developed into a retro-arc basin.

  4. Tourism, Transnationality and Ethnolinguistic Vitality: The Welsh in the Chubut Province, Argentina

    Science.gov (United States)

    Johnson, Ian

    2010-01-01

    This article aims to develop the concept of ethnolinguistic vitality by adopting a qualitative approach to vitality rather than the statistical approach traditionally used. Ten small-size focus group style interviews were held with members of the Welsh-Argentinean community in the Chubut Province in the south of Argentina in order to explore…

  5. Crecimiento y desarrollo de una población infanto juvenil de la provincia de Chubut

    Directory of Open Access Journals (Sweden)

    Torres, María Fernanda

    1999-01-01

    Full Text Available La diferenciación y adaptación ontogenética son temas centrales en antropología biológica por cuanto su modificación puede afectar la dinámica evolutiva poblacional. Numerosos factores estresantes actúan provocando variación en la expresión fenotípica y nuevas respuestas adaptativas. En el presente trabajo se determinó el crecimiento de niños de 5 a 14 años contrastando con estándares internacionales. La muestra se constituyó con 473 escolares de Río Mayo (Chubut, de ambos sexos. Se relevaron y calcularon variables corporales. Para la comparación con los estándares los datos fueron convertidos a escores z y contrastados además mediante pruebas de Wilcoxon. La estadística empleada consistió en análisis multifactorial de la varianza y pruebas de LSD. Si bien hubo crecimiento en todos los grupos etáreos analizados, los valores obtenidos difirieron significativamente de los correspondientes al estándar. En varones, a excepción del pliegue subescapular, que presentó escores z superiores al estándar las restantes variables se ubicaron entre 0 y -2 DS, siendo más afectadas las estaturas total y sentado y el área muscular. En mujeres, se observó una situación similar a excepción del área adiposa y la masa corporal, con valores mayores al estándar. Estos resultados evidencian la presencia de una desnutrición que abarca toda la franja etárea. La disminución de la talla y el aumento del tejido adiposo constituyen sin duda, respuestas adaptativas que permiten la supervivencia de los individuos frente a la injuria nutricional.

  6. Spatial distribution, feeding and length–mass relationships of Diamphipnopsis samali (Plecoptera, Diamphipnoidae in a North Patagonia Andean stream, Argentina

    Directory of Open Access Journals (Sweden)

    Guillermo H. OMAD

    2015-01-01

    Full Text Available RESUMEN. Fueron estudiados algunos aspectos de la biología y ecología (patrones de distribución espacial, hábitos alimenticios y relación largo-masa de una población de Diamphipnopsis samali en un arroyo de primer orden que atraviesa un bosque exótico de pino en el centro-norte de Patagonia (Chubut, Argentina. Dos series de muestreos fueron realizados durante períodos de aguas altas y aguas bajas. Toda la información fue tratada con ANOVAS de dos factores y efectos fijos para evaluar diferencias significativas. El análisis de las piezas bucales de D. samali indica que corresponden a un tipo intermedio entre el tipo carnívoro y herbívoro-detritívoro. El contenido estomacal muestra que esta especie se alimenta de hifas fúngicas y madera, aunque en los estadios tempranos se encuentran restos de insectos. No se hallaron diferencias significativas en la alimentación entre períodos de aguas altas y aguas bajas, sin embargo, existieron diferencias significativas entre la dieta de larvas grandes y pequeñas. Fue clara la preferencia por el sustrato tronco y cascada, y también significativamente diferente entre los tipos pozón y corredera. No hubo diferencias significativas en la elección de hábitat entre los períodos de aguas bajas y aguas altas. Esta especie endémica de Patagonia parece estar bien adaptada a la presencia de un bosque ripario exótico, utilizando los troncos caídos como alimento y refugio.

  7. Mortalidad en la población galesa de Gaiman, provincia de Chubut, Argentina

    Directory of Open Access Journals (Sweden)

    Caratini, Alicia Liliana

    2005-01-01

    Full Text Available El objetivo de este trabajo es analizar la evolución en el tiempo de las defunciones y de las causas de muerte por edad y sexo de la población galesa de Gaiman, provincia de Chubut, Argentina. Los datos fueron obtenidos de las Actas de Defunción del Archivo del Registro Civil de la ciudad de Rawson, Chubut. El período de estudio se extendió de 1892 a 1961 y para su descripción y análisis se lo dividió en decenios. Se registraron 2103 defunciones de las cuales 1039 (49% correspondieron a galeses y sus descendientes, lo cual representa un promedio de 14.6 muertes por año. Se detectó una sobremortalidad masculina (59%, esperable en una población colonizadora con predominio de varones. Se observó un incremento, en el tiempo, de la edad media de defunción, lo que indica mejoras en las condiciones socioeconómicas y de salud de la población. La mortalidad infantil y los natimortos representaron el 20% y el 11%, respectivamente, de las defunciones y se constató una transición desde una mortalidad provocada por enfermedades de naturaleza exógena a otra de causalidad endógena. Al compararse nuestros datos con los de la provincia de Chubut y el país, se comprobó, en todos los casos, un descenso de la mortalidad en el tiempo, aunque en Gaiman esa disminución fue más significativa, probablemente por la atención que la comunidad le dedicaba a la educación y a la salud.

  8. Lesiones traumáticas y marcas taxonómicas en una muestra de cráneos del norte de Patagonia

    Directory of Open Access Journals (Sweden)

    Gordón, Florencia

    2007-01-01

    Full Text Available Actualmente se está llevando a cabo una investigación orientada a evaluar la frecuencia y el tipo de lesiones traumáticas atribuibles a situaciones de violencia interpersonal en muestras de restos óseos humanos del norte de Patagonia asignables al Holoceno tardío. Para dicho estudio, resulta indispensable un análisis de tipos e intensidad de variables postdepositacionales con el fin de estimar su impacto sobre la visibilidad de las huellas culturales. Sería esperable que en las submuestras que exhiben un grado mayor de alteración postdepositacional el registro de traumas sea menor y viceversa. El tamaño mínimo de la muestra analizada es de 400 cráneos procedentes de las cuencas inferiores de los ríos Negro y Chubut, pertenecientes a las colecciones del Museo de Ciencias Naturales de La Plata. Los resultados obtenidos hasta el presente indican que la muestra de Río Negro es la que mayor frecuencia de traumas y alteraciones tafonómicas presenta, mientras que la de Chubut exhibe baja frecuencia tanto de marcas tafonómicas como de traumas. Las variables postdepositacionales no parecen estar afectando significativamente a las observaciones de traumas culturales, por lo que las diferencias regionales en la frecuencia de este tipo de lesiones parecen reflejar diferencias reales en la exposición a factores causantes de lesiones traumáticas, entre las que se cuenta la violencia interpersonal.

  9. Subduction of the South-Chile active spreading ridge: a 17 Ma to 3 Ma magmatic record in central Patagonia (western edge of Meseta del Lago Buenos Aires, Argentina)

    Science.gov (United States)

    Boutonnet, Emmanuelle; Arnaud, Nicolas; Guivel, Christèle; Lagabrielle, Yves; Scalabrino, Bruno; Espinoza, Felipe

    2010-05-01

    The Chile Triple Junction is a natural laboratory to study the interactions between magmatism and tectonics during the subduction of an active spreading ridge beneath a continent. The MLBA plateau (Meseta del Lago Buenos Aires) is one of the Neogene alkali basaltic plateaus located in the back-arc region of the Andean Cordillera at the latitude of the current Chile Triple Junction. The genesis of MLBA can be related with successive opening of slabs windows beneath Patagonia: within the subducting Nazca Plate itself and between the Nazca and Antarctic plates. Detailed 40Ar/39Ar dating and geochemical analysis of bimodal magmatism from the western flank of the MLBA show major changes in the back-arc magmatism which occurred between 14.5 Ma and 12.5 Ma with the transition from calc-alkaline lavas (Cerro Plomo) to alkaline lavas (MLBA) in relation with slab window opening. In a second step, at 4- 3 Ma, alkaline felsic intrusions were emplaced in the western flank of the MLBA coevally with the MLBA basalts with which they are genetically related. These late OIB-like alkaline to transitional basalts were generated by partial melting of the subslab asthenosphere of the subducting Nazca plate during the opening of the South Chile spreading ridge-related slab window. These basalts differentiated with small amounts of assimilation in shallow magma chambers emplaced along transtensional to extensional zones. The close association of bimodal magmatism with extensional tectonic features in the western MLBA is a strong support to the model of Patagonian collapse event proposed to have taken place between 5 and 3 Ma as a consequence of the presence of the asthenospheric window (SCR-1 segment of South Chile Ridge) below the MLBA area.

  10. Nocturnal feeding under artificial light conditions by Brown-hooded Gull (Larus maculipennis) in Puerto Madryn harbour (Chubut Province, Argentina)

    NARCIS (Netherlands)

    Leopold, M.F.; Philippart, C.J.M.; Yorio, P.

    2010-01-01

    This paper describes nocturnal, marine feeding behaviour in the Brown-hooded Gull (Larus maculipennis) in November 2009. The gulls assembled at night at the end of a long pier, running 800 m offshore into the Golfo Nuevo, at Puerto Madryn, Chubut Province, Argentina. Powerful lights predictably ligh

  11. Marine reptiles from the Late Cretaceous of northern Patagonia

    Science.gov (United States)

    Gasparini, Z.; Casadio, S.; Fernández, M.; Salgado, L.

    2001-04-01

    During the Campanian-Maastrichtian, Patagonia was flooded by the Atlantic and reduced to an archipelago. Several localities of northern Patagonia have yielded marine reptiles. Analysis of several assemblages suggests that the diversity and abundance of pelagic marine reptiles in northern Patagonia was higher by the end of the Cretaceous than previously thought. Several plesiosaurids, including Aristonectes parvidens and the polycotylid Sulcusuchus, and the first remains of mosasaurinae have been found. The Cretaceous marine reptile record from South America is scanty. Nevertheless, materials described here suggest that Tethyan and Weddelian forms converged in northern Patagonia, as seen with invertebrates.

  12. Turismo sostenible y proyectos hidroeléctricos: contradicciones en la patagonia chilena

    Directory of Open Access Journals (Sweden)

    Gabriel Inostroza

    2014-01-01

    Full Text Available El artículo analiza las perspectivas del turismo sostenible en la Patagonia chilena en relación a la probable implantación de centrales hidroeléctricas en su territorio. Se estudia el impacto de un gran proyecto hidroeléctrico en la región de Aysén (Chile y su repercusión en el turismo. Se concluye que la construcción y operación de grandes embalses y presas con sus correspondientes líneas de trasmisión eléctrica atentarían contra la principal ventaja competitiva del sector turístico de la Patagonia: una naturaleza que aún se conserva y que se ha proyectado en el imaginario social.

  13. Age and composition of granulite xenoliths from Paso de Indios, Chubut province, Argentina

    NARCIS (Netherlands)

    Castro, Antonio; Aragon, Eugenio; Diaz-Alvarado, Juan; Blanco, Idael; Garcia-Casco, Antonio; Vogt, Katharina; Liu, D-Y.

    2011-01-01

    Granulite xenoliths enclosed in Paleogene alkali basalts from the locality of Paso de Indios in The Argentinean Patagonia, have been studied for petrology, geochemistry and U–Pb SHRIMP zircon geochronology. These are lower crust xenoliths composed of pyroxene and plagioclase dominantly. Symplectitic

  14. Geología de la quebrada Honda, cuenca del lago La Plata, Chubut Geology of the Quebrada Honda, basin of Lago La Plata, Chubut

    Directory of Open Access Journals (Sweden)

    G.V. Depine

    2004-12-01

    Full Text Available La quebrada Honda, situada en el sur de la cuenca de los lagos La Plata y Fontana, en la provincia de Chubut, presenta una columna estratigráfica que comienza en el Jurásico superior con rocas calcoalcalinas de arco volcánico intermedias a ácidas de la Formación Lago La Plata. Las rocas sedimentarias que rellenan la cuenca de intraarco neocomiana corresponden al Grupo Coyhaique, dentro del cual se encuentran las Formaciones Tres Lagunas y Katterfeld, que se ubican dentro de un modelo paleoambiental como cortejo sedimentario de borde de plataforma, sucedido por un cortejo transgresivo, cuya edad es acotada al Hauteriviano inferior, debido al hallazgo de restos de Favrella americana en pelitas de la Formación Katterfeld. Vinculados con la extensión que da lugar a la cuenca se registran los cuerpos hipabisales calcoalcalinos básicos del Gabro Quebrada Honda y se los relaciona con un volcanismo de características más evolucionadas de la Formación Don Rueda, de edad neocomiana tardía. Si bien este magmatismo de arco volcánico es subaéreo, presenta indicios de interacción con cuerpos de agua por lo que corrobora la concomitancia de este evento con la sedimentación póstuma de Grupo Coyhaique. Se registra un evento de inversión tectónica que tendría una edad máxima de 80 Ma.The quebrada Honda is situated in the Lago La Plata-Fontana basin in Chubut. The stratigraphy of the area begins in the Upper Jurassic with the calc-alkaline intermediate to acidic Lago La Plata Formation rocks. The Neocomian Coyhaique Group, which includes the Tres Lagunas and Katterfeld Formations, is the sedimentary filling of the intraarc basin that was developed by that time. These units are included in a paleoenviromental model as a shelf-margin system tract followed by a transgressive system tract. The discovery of Favrella americana in the Katterfeld Formation constrains to the Early Hauterivian the age of these sequences. The hypabissal calc

  15. Hydrographic data from the GEF Patagonia cruises

    Directory of Open Access Journals (Sweden)

    M. Charo

    2014-02-01

    Full Text Available The hydrographic data reported here were collected within the framework of the Coastal Contamination, Prevention and Marine Management project (GEF Patagonia, which was part of the scientific agenda of the United Nations Development Program (UNDP. The project goal was to strengthen efforts to improve sustainable management of marine biodiversity and reduce pollution of the Patagonia marine environment. The observational component of the project included three multi-disciplinary oceanographic cruises designed to improve the knowledge base of the marine environment and to determine the seasonal variability of physical, biological and chemical properties of highly productive regions in the southwest South Atlantic continental shelf. The cruises were carried out on board R/V Ara Puerto Deseado, in October 2005 and March and September 2006. In each cruise, hydrographic stations were occupied along cross-shelf sections spanning the shelf from near-shore to the western boundary currents between 38° and 55° S. This paper reports the quasi-continuous vertical profiles (CTD and underway surface temperature and salinity data collected during the GEF Patagonia cruises. These data sets are available at the National Oceanographic Data Center, NOAA. US, doi:10.7289/V5RN35S0.

  16. Gravimetric model of the Gastre trough, province of Chubut, Argentina; Modelo gravimetrico en la fosa de Gastre, provincia de Chubut, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Lince Klinger, F.; Nacif, S.; Martinez, M. P.; Gimenez, M. E.; Ruiz, F.; Alvarez, O.

    2011-07-01

    A gravimetric study of the Gastre trough in the Province of Chubut, to the southwest of the Canadon Asfalto basin, has allowed us to determine the geometry of its crystalline basement. Using filtering techniques we were able to map residual Bouguer anomalies, which show the heterogeneities situated within the upper crust, some of which are linked to recognised geological structures. The gravimetric minima in the residual Bouguer anomaly map are associated with graben-type basins, flanked by positive gravity values associated with alignments identified on the surface and with the overall topographic relief of the Gastre trough. After suitable treatment of the density values of the outcrops and seismic data we were able to construct a 2D density model, perpendicular to the trough, which indicated a depth of 3600 m. The importance of this study lies in the fact that it has been possible to arrive at a gravimetric characterization of the Gastre trough in the Canadon Asfalto basin sector, a potentially hydrocarbon-bearing area hitherto lacking in reliable data concerning its subsoil. (Author)

  17. Petrología de la secuencia volcánica cenozoica en el área del arroyo Ranquil Huao: Meseta de Somún Curá. Patagonia Extraandina Petrology of volcanic sequence in the Arroyo Ranquil Huao: Meseta de Somún Curá,. extra-andean patagonia

    Directory of Open Access Journals (Sweden)

    M. B. Remesal

    2002-09-01

    Full Text Available En el norte de la Patagonia extraandina, involucrando parte de las provincias geográficas de Río Negro y Chubut se extiende un amplio derrame basáltico tipo plateau. El valle del arroyo Ranquil Huao, en el sector austral del plateau, en las proximidades de la localidad de Telsen, expone una secuencia interesante y bastante completa de esa asociación volcánica cenozoica. En este corte es posible estudiar no sólo los flujos basálticos correspondientes a la Formación Somún Curá, sino también los derrames denominados Basalto La Mesada, incluidos en la Superunidad Quiñelaf y los depósitos tobáceos del Grupo Sarmiento. Los basaltos de la Formación Somún Curá presentan rasgos petrográficos y geoquímicos similares a los del Basalto La Mesada (Superunidad Quiñelaf. El flujo piroclástico que se intercala en la parte más alta de la Formación Somún Curá complementa la estratigrafía conocida para esta unidad. Las características de las basanitas aflorantes en el tramo medio del valle del arroyo Ranquil Huao permiten diferenciarlas de las rocas que constituyen las otras unidades basálticas en la secuencia.In the northern side of the extra andean Patagonia, in portions of Rio Negro and Chubut provinces, extensive basaltic lava flows plateaux type are exposed. On the southern side of the plateaux, in the Ranquil Huau stream valley, close to Telsen locality, a large succesion of volcanic and vocaniclastic rocks is exposed. The basaltic lava flows of Somuncura Formation and the Basalto La Mesada (Quiñelaf Superunit and the volcanisclastic deposits of the Sarmiento Group are exposed in the area. The different groups of basalts are identified by petrographyc and geochemical distinctive features. In the upper level of Somún Curá Formation a basic pyroclastic flow is interbedded. The basic rocks exposed in the medium level of the valley have distinctive characteristics and they are named as Basanitas Ranquil Huao. The analized units

  18. Conocimiento tradicional y autosuficiencia: la herbolaria rural en la Meseta Central del Chubut (Argentina)

    OpenAIRE

    Richeri, Marina; Ladio, Ana Haydee; Beeskow, Ana Maria

    2016-01-01

    Se estudió la herbolaria utilizada en una zona rural de la estepa patagónica habitada predominantemente por descendientes del pueblo originario mapuche - tehuelche. Este trabajo pone énfasis en la versatilidad medicinal de las especies y su posible aporte a la autosuficiencia de las poblaciones campesinas. La metodología se basó en entrevistas libres y semiestructuradas además de recorridos junto a informantes. Los entrevistados citaron 45 especies medicinales (52% nativas, 48% introducidas) ...

  19. Estratigrafía, análisis de facies y paleoambientes de la formación cañadón asfalto en el depocentro jurásico cerro Cóndor, provincia del Chubut Stratigraphy, facies analysis and paleoenvironments of the Cañadón Asfalto Formation, Jurassic Cerro Cóndor depocenter, Chubut province

    Directory of Open Access Journals (Sweden)

    Nora Cabaleri

    2010-05-01

    Full Text Available El depocentro Cerro Cóndor representa la secuencia estratigráfica del Jurásico continental más completa de la cuenca de Cañadón Asfalto y de Sudamérica austral. Se sitúa en la Patagonia extraandina, en ambas márgenes del río Chubut medio. La sedimentación en esta cuenca pull apart, acompañada por efusiones de basalto olivínico, comenzó en el Jurásico Medio temprano. Predominan en la Formación Cañadón Asfalto los depósitos lacustres caracterizados por asociaciones de facies carbonáticas y siliciclásticas intercaladas con rocas lávicas en la base y depósitos piroclásticos hacia el techo de la unidad. Se describe el desarrollo de facies a lo largo de un corte norte-sur que abarca las secciones de estancia El Torito y de los cañadones Los Loros, Las Chacritas, Carrizal, Asfalto y Lahuincó. Las facies/microfacies carbonáticas están representadas por mudstones, wackestones,packstones, grainstones y calizas microbialíticas características de ambientes litorales, marginales y palustres. En la Formación Cañadón Asfalto se distinguen un miembro inferior (Las Chacritas, constituido por calizas, lutitas, areniscas y conglomerados, intercalados con basaltos olivínicos y por otro superior (Puesto Almada compuesto por tobas, tufitas, lutitas y areniscas. El primero es portador de una asociación palinológica de edad bajociano-bathoniana y el segundo de dinosaurios de edad tithoniana. Se describen detalladamente e ilustran las secciones estratigráficas de ambos miembros de la formación en sus localidades tipo, cañadón Las Chacritas y estancia el Torito y se reconstruyen los paleoambientes del depocentro desde el Aaleniano al Tithoniano. La edad del miembro Puesto Almada en su localidad tipo se obtuvo mediante una datación radimétrica (K/Ar de biotitas provenientes de una delgada capa de toba volcánica (147,1 ± 3,3 Ma, Tithoniano proveniente de la parte superior de la unidad.The Cerro Cóndor depocenter represents the

  20. The Pali Aike Windstreak Field, Southern Patagonia, Argentina

    Science.gov (United States)

    Rodriguez, J. A. P.; Zimbelman, J. R.; Kargel, J. S.; Tanaka, K. L.; Yamamoto, A.; Sasaki, S.

    2008-03-01

    Windstreaks are amongst the most common aeolian landforms on Mars, yet they are extremely rare on Earth. We have identified and carried out field based observations of an outstanding zone of windstreaks in southern Patagonia Argentina.

  1. Monitoreo de DDI en la zona andina de la provincia de Chubut (2004

    Directory of Open Access Journals (Sweden)

    J. L. Tellechea

    2009-03-01

    Full Text Available Un total de 444 alumnos de escolaridad primaria, de ambos sexos, fue estudiado en este monitoreo de bocio endémico en dos localidades de la zona andina de la provincia de Chubut: Esquel (292 niños y Cushamen (152 niños. La edad de los escolares osciló entre 5 y 13 años. La palpación tiroidea fue hecha por el conjunto de los médicos participantes. Sin embargo, con la finalidad de aunar criterios con lo realizado previamente (1-20, se tomó como única referencia la palpación de H.N., que se llevó a cabo en la totalidad de los niños estudiados. La definición del grado de bocio fue similar a la utilizada en los otros relevamientos (1. Se determinó la yoduria en muestras casuales de orina emitidas por los niños una vez que fueron palpados (139 de Esquel y 133 de Cushamen. Se recolectaron 213 muestras de sal de consumo hogareño de Esquel y 144 de Cushamen, para medir su contenido en yodo. El examen palpatorio de los niños reveló la existencia de bocio grado 1 solamente. La prevalencia de bocio encontrada fue de 2,1% en Esquel y de 3,3% en Cushamen. Los niveles de yoduria alcanzaron, en Esquel, una media de 238±119(DSμg/L y una mediana de 214μg/L, al tiempo que en Cushamen la media fue de 270±187μg/L y la mediana de 238μg/L. El contenido de yodo de las sales que aportaron los alumnos tuvieron un nivel adecuado de yodo, sobre todo en aquellas de consumo masivo. De esta manera, observamos que en la ciudad de Esquel el promedio de yodo en la sal, tomada en conjunto, fue de 30,6 ± 8,1 mg/Kg, mientras que para Cushamen fue de 31,1 ± 10,5 mg/Kg. Al analizar las concentraciones de yodo <15mg/Kg, observamos que fue del 3,0% en Esquel y del 7,4% en Cushamen. Teniendo en cuenta la línea de corte del 10% que fija el ICCIDD (21 como valor óptimo, podemos observar que la situación de ambas poblaciones es muy satisfactoria. Concluimos que en estas dos poblaciones de la zona andina de la provincia de Chubut ya no existe bocio endémico.

  2. Recuperar un paisaje : Prospecciones en la estancia san ramón, (Chubut, Argentina)

    OpenAIRE

    Castro, Alicia Susana

    2005-01-01

    Los trabajos arqueológicos que se vienen realizando en el Norte de Patagonia en el marco de diferentes proyectos UBACYTI tendieron a determinar indicadores arqueológicos del uso del espacio en una escala macro-regional sobre la base de la información etnográfica con que se contaba para los Tehuelches del norte (Aschero y otros 1983; Nacuzzi y Pérez de Micou 1985; 1994; Pérez de Micou 1987a y b; 2003; ). Estas investigaciones estuvieron enmarcadas en diferentes proyectos financiados por la Sec...

  3. Variation in the proximate composition and fatty acid profile recovered from Argentine hake (Merluccius hubbsi waste from Patagonia

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    Cretton, M.

    2016-03-01

    Full Text Available The fish processing operations in Patagonia produce large amounts of waste. The main fishery resource in Argentina is the Argentine hake (Merluccius hubbsi. The ports of the province of Chubut (the most important of which are Puerto Madryn, Rawson and Comodoro Rivadavia, together with Caleta Paula Port (province of Santa Cruz, in the Argentine Patagonia, capture more than 82,000 tons of hake annualy, 80% of which are of M. hubbsi, which is mostly converted into fillets. From this capture, about 2,296 tons of liver would be available for the extraction of oil. To promote the recovery and industrial use of fish oil, in the present study, we determined the variation in the proximate composition and fatty acid profile of Argentine hake waste from the ports mentioned above at different catch times. Proximate composition was determined according of the Official Methods of Analysis (AOAC. Fatty acid profile was analyzed by gas chromatography of the fatty acid methyl esters (FAMEs. A standard mixture of FAMEs was run under identical conditions to identify the compounds on the basis of their retention times. Fatty acids were quantified using heptadecanoic acid (C17:0 as internal standard. The highest lipid recovery (27.0 to 41.8% of total lipids was obtained from the liver fraction. Palmitic acid (C16:0, oleic acid (18:1 n9, docosahexaenoic acid (22:6 n3, eicosapentaenoic acid (20:5 n3 and palmitoleic acid (16:1 were the main constituents. Protein levels in viscera without livers (V-L were higher than those in the liver. The extraction of marine fish oil and the production of fish offal meal from waste from fish factories would contribute to the sustainability of the regional industry, because it would also decrease the volume of waste, with benefits to the environment.El procesamiento de pescados en Patagonia produce gran cantidad de residuos. El recurso de pesca más importante en la Argentina es la merluza argentina (Merluccius hubbsi. En Patagonia

  4. Thermal structure of proglacial lakes in Patagonia

    Science.gov (United States)

    Sugiyama, Shin; Minowa, Masahiro; Sakakibara, Daiki; Skvarca, Pedro; Sawagaki, Takanobu; Ohashi, Yoshihiko; Naito, Nozomu; Chikita, Kazuhisa

    2016-12-01

    Calving glaciers are rapidly retreating in many regions under the influence of ice-water interactions at the glacier front. In contrast to the numerous researches conducted on fjords in front of tidewater glaciers, very few studies have been reported on lakes in which freshwater calving glaciers terminate. To better understand ice-water interactions at the front of freshwater calving glaciers, we measured lakewater temperature, turbidity, and bathymetry near Glaciar Perito Moreno, Upsala, and Viedma, large calving glaciers of the Southern Patagonia Icefield. The thermal structures of these lakes were significantly different from those reported in glacial fjords. There was no indication of upwelling subglacial meltwater; instead, turbid and cold glacial water discharge filled the region near the lake bottom. This was because water density was controlled by suspended sediment concentrations rather than by water temperature. Near-surface wind-driven circulation reaches a depth of 180 m, forming a relatively warm isothermal layer (mean temperature of 5-6°C at Perito Moreno, 3-4°C at Upsala, and 6-7°C at Viedma), which should convey heat energy to the ice-water interface. However, the deeper part of the glacier front is in contact with stratified cold water, implying a limited amount of melting there. In the lake in front of Glaciar Viedma, the region deeper than 120 m was filled entirely with turbid and very cold water at pressure melting temperature. Our results revealed a previously unexplored thermal structure of proglacial lakes in Patagonia, suggesting its importance in the subaqueous melting of freshwater calving glaciers.

  5. Monitorieo de DDI en el noreste de la provincia de Chubut (2004

    Directory of Open Access Journals (Sweden)

    G. S. Zarza

    2008-06-01

    Full Text Available Un total de 668 alumnos de escolaridad primaria, de ambos sexos, fue estudiado en este monitoreo de bocio endémico en dos ciudades del noreste de la provincia de Chubut: Puerto Madryn (493 niños y Trelew (175 niños. La edad de los escolares osciló entre 5 y 15 años. La palpación tiroidea fue hecha por el conjunto de los médicos participantes. Sin embargo, con la finalidad de aunar criterios con lo realizado previamente (1-18, se tomó como única referencia la palpación de H. N., que se llevó a cabo en la totalidad de los niños estudiados. La definición del grado de bocio fue similar a la utilizada en los otros relevamientos (1. Se determinó la yoduria en muestras casuales de orina emitidas por los niños una vez que fueron palpados (161 de Puerto Madryn y 139 de Trelew. Se midió el contenido de yodo en 467 muestras de sal de consumo hogareño de Puerto Madryn y en 161 de Trelew. El examen palpatorio de los niños reveló la existencia de bocio grado 1 solamente. La prevalencia de bocio encontrada fue de 3,9 % en Puerto Madryn y de 2,9 % en Trelew. Los niveles de yoduria alcanzaron, en Puerto Madryn, una media de 188±95,8(DS μg/L y una mediana de 171 μg/L, al tiempo que en Trelew la media fue de 245±102,3 μg/L y la mediana de 196 μg/L. El contenido de yodo de las sales que aportaron los alumnos, si bien varió según la marca de sal utilizada, tuvieron un nivel relativamente adecuado de yodo en aquellas de consumo masivo. De esta manera, observamos que en la localidad de Puerto Madryn el promedio de yodo en la sal, tomada en conjunto, fue de 32,0 ± 10,9 mg/Kg, mientras que para Trelew fue de 31,5 ± 8,5 mg/Kg. Al analizar las concentraciones de yodo <15 mg/Kg, observamos que fue del 9 % en Puerto Madryn y del 5 % en Trelew. Teniendo en cuenta la línea de corte del 10 % que fija el ICCIDD (19 como valor óptimo, podemos observar que la situación de ambas poblaciones es satisfactoria. Concluimos que en estas dos ciudades del

  6. Evolución geomorfológica y cronología relativa de los niveles aterrazados del área adyacente a la desembocadura del río Chubut al Atlántico (Provincia del Chubut Geomorphological evolution and relative chronology of terrace levels adjacent to the Chubut River mouth to the Atlantic (Chubut Province.

    Directory of Open Access Journals (Sweden)

    Emilio F González Díaz

    2011-12-01

    Full Text Available Se describe un antiguo abanico aluvial y su posterior evolución. Las acumulaciones del antiguo abanico aluvial han sido interpretadas como la continuidad septentrional de los rodados patagónicos de la meseta Montemayor, una propuesta que es rebatida. La base metodológica del reconocimiento del antiguo abanico aluvial y su distinción genética y temporal, la constituyó el análisis geomórfico y la evaluación altimétrica. Su asignación temporal es un problema aún no resuelto. La metodología condujo a diferenciar tres sistemas geomórficos o niveles, relacionados con sucesivos episodios de agradación y erosión, los que ocupan posiciones cada vez más inferiores, coincidiendo con el complejo paleodrenaje del antiguo abanico aluvial. Sus desarrollos sucesivos son vinculados con protoríos Chubut 1, 2, 3 propuestos y el correspondiente a un paleovalle Simpson. Pese a las limitaciones apuntadas, se propone que el modelo evolutivo del antiguo abanico aluvial responde a una estructura de corte y relleno, que avalaría una composición poliformacional del antiguo abanico aluvial y además la migración progresiva del paleodrenaje hacia el sur. Un análisis geomorfológico y altimétrico diferenció un nivel superior integrado por restos de tres planicies (Pa, Pm y Pb, un nivel medio con dos terrazas (T1 y T2 y un complejo nivel inferior de cinco terrazas (T3, T4, T5 T6 y T7. Evidencias relícticas de los paleodrenajes propuestos son los paleovalles Estancia Paz y Don Morgan-Saraza del nivel superior. La edad del antiguo abanico aluvial basada en la evolución geomórfica del área de estudio, es tentativamente asignada a un incierto lapso del Pleistoceno superior entre el interglacial Sangamon y fines de la última glaciación.An ancient alluvial fan and its subsequent evolution are described. Ancient alluvial fan accumulations have been interpreted as the northern continuation of the rodados patagónicos of the Montemayor Plateau, a proposal

  7. La identidad en la encrucijada: la comunidad galesa del Chubut y las conmemoraciones del Centenario y Bicentenario de la Revolución de Mayo

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    Geraldine Lublin

    2013-12-01

    Full Text Available El presente artículo se propone rastrear a grandes rasgos la relación ―especial‖ entre el estado nacional argentino y, a partir de 1958, la provincia de Chubut por una parte y los colonos galeses que se establecieron en Chubut desde 1865 y sus descendientes por otra, a través del análisis de la posición de la colectividad galesa del Chubut en dos momentos históricos destacados: el Centenario y el Bicentenario de la Revolución de Mayo (1810. Al corresponderse el perfil de los galeses con la idea de poblaciones "civilizadas" que las autoridades pretendían impulsar en desmedro de los legítimos pobladores originales, estas políticas dieron lugar a una fuerte identificación histórica de la Provincia de Chubut con la llamada "gesta galesa". Se generó asimismo una peculiar dinámica triangular de las relaciones estatales, cuya evolución a través del tiempo ha desembocado en la actual promoción de la identidad chubutense como el resultado de la fusión de las culturas de los tehuelches originarios y los colonos galeses.

  8. Geología de la quebrada Honda, cuenca del lago La Plata, Chubut

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    G.V. Depine

    2004-12-01

    Full Text Available La quebrada Honda, situada en el sur de la cuenca de los lagos La Plata y Fontana, en la provincia de Chubut, presenta una columna estratigráfica que comienza en el Jurásico superior con rocas calcoalcalinas de arco volcánico intermedias a ácidas de la Formación Lago La Plata. Las rocas sedimentarias que rellenan la cuenca de intraarco neocomiana corresponden al Grupo Coyhaique, dentro del cual se encuentran las Formaciones Tres Lagunas y Katterfeld, que se ubican dentro de un modelo paleoambiental como cortejo sedimentario de borde de plataforma, sucedido por un cortejo transgresivo, cuya edad es acotada al Hauteriviano inferior, debido al hallazgo de restos de Favrella americana en pelitas de la Formación Katterfeld. Vinculados con la extensión que da lugar a la cuenca se registran los cuerpos hipabisales calcoalcalinos básicos del Gabro Quebrada Honda y se los relaciona con un volcanismo de características más evolucionadas de la Formación Don Rueda, de edad neocomiana tardía. Si bien este magmatismo de arco volcánico es subaéreo, presenta indicios de interacción con cuerpos de agua por lo que corrobora la concomitancia de este evento con la sedimentación póstuma de Grupo Coyhaique. Se registra un evento de inversión tectónica que tendría una edad máxima de 80 Ma.

  9. Variabilidad morfométrica dental en muestras arqueológicas tardías del sudeste de la región pampeana y noreste de Patagonia

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    Bernal, Valeria

    2003-01-01

    Full Text Available Recientemente, se ha postulado la ocurrencia de un proceso de expansión demográfico y geográfico de las poblaciones del norte de Patagonia durante el Holoceno tardío, con posterioridad a la denominada Anomalía Climática Medieval (ca. 800 - 1350 AD. En el marco del proyecto "La Dinámica Evolutiva de Poblaciones y Metapoblaciones Humanas en las Regiones Pampeana y Patagónica (33°- 52° Lat. Sur durante el Holoceno Tardío" (Subsidio de Inicio de Carrera Fundación Antorchas Nº 14116-111 se están desarrollando estudios orientados a analizar la variación morfológica craneal y postcraneal de las poblaciones humanas de ambas regiones, con el fin de discutir la dinámica poblacional durante el Holoceno tardío. En este contexto, el objetivo del presente trabajo es analizar la variabilidad morfométrica dental de muestras diacrónicas procedentes del SE de la Región Pampeana y NE de Patagonia (v.g. valles de los ríos Chubut y Negro, litoral atlántico sudbonaerense. Las variables consideradas incluyen diámetros mesiodistales y bucolinguales sobre la corona dental y el margen cervical, medidos sobre piezas dentales permanentes. Los resultados obtenidos mediante el empleo de test estadísticos uni y multivariados, serán discutidos con relación al resto de la evidencia morfológica actualmente disponible para ambas regiones.

  10. Proterozoic SCLM domains beneath Southern Patagonia

    Science.gov (United States)

    Mundl, Andrea; Ntaflos, Theodoros; Ackerman, Lukas; Bizimis, Michael; Bjerg, Ernesto

    2014-05-01

    Alkali basalt hosted mantle xenoliths from 3 different areas in South Patagonia were studied with regard to their petrography and chemical, as well as their Re-Os and Lu-Hf isotopic compositions. The Pali Aike Volcanic Field (PAVF) located in the very south of Patagonia comprises sample localities Salsa, El Ruido and Potrok Aike. About 300 km north, in the western part of Patagonia, samples were collected at Tres Lagos and further north-east, within and at the edge of the Deseado massif, are sample localities Gobernador Gregores and Don Camilo, respectively. The collected sample suite comprises sp-lherzolites, sp-harzburgites, one sp-dunite and exclusively within PAVF also sp-gt-lherzolites and sp-gt-harzburgites. Textures are mostly protogranular with very few samples showing weak foliation. Whole rock Al2O3 and CaO contents range from 0.63 to 3.54 wt.% and 0.24 to 3.44 wt.%, respectively and exhibit a linear correlation with MgO ranging from 39.2 to 49 wt.%. The more refractory peridotites are represented by samples from the PAVF while samples from the Deseado massif are generally more fertile. Indications for the formation age of SCLM domains can be provided using the Re-Os isotopic system. A suite of 24 modally unmetasomatised sp-lherzolites and sp-harzburgites analyzed for Re-Os isotopic composition reveals Neo- to Paleoproterozoic rhenium depletion ages. Don Camilo and Gobernador Gregores lherzolites indicate a SCLM formation in Mesoproterozoic times (0.9 to 1.3 Ga). Tres Lagos harzburgites reveal slightly older formation ages with a max. TRD of 1.7 Ga. Samples from within the PAVF vary more strongly in 187Os/188Os ratios with Neo- to late Paleoproterozoic TRDs. 3 refractory samples indicate an at least 2.4 Ga old formation age of the SCLM domain underneath PAVF. Hf isotopic data combined with the information obtained from Os isotopic analyses provide new information on potential metasomatic overprints and their probable timing. Negative to low positive

  11. Estado de conocimiento del orden Ephemeroptera en la Patagonia Current knowledge of Patagonian Ephemeroptera

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    Pablo Pessacq

    2009-06-01

    Full Text Available El conocimiento actual del orden Ephemeroptera en la Patagonia se debe en gran parte a la labor original y compilatoria de M.L. Pescador, W.L. Peters y E. Domínguez, llevada a cabo en la década del 80 del siglo pasado. Se suman a ésta, importantes contribuciones que han conducido a un adecuado conocimiento del grupo en la cordillera norte y centro de la Patagonia, aunque menor en la zona austral de esta región (Santa Cruz y Tierra del Fuego y las áreas de estepa. Merced al trabajo de campo realizado en 80 sitios de muestreo relevados en el marco del "Darwin Initiative Project" en el Parque Nacional Nahuel Huapi, se incluyen aquí nuevos registros para la Argentina (Hapsiphlebia anastomosis Demoulin, la región Andina (Apobaetis Day y la provincia de Río Negro (Chaquihua bullocki (Navás, Andesiops ardua (Lugo-Ortíz & McCafferty, Murphyella needhami Lestage y Dactylophlebia carnulenta Pescador & Peters. Con estos registros, la riqueza de Ephemeroptera de la Patagonia alcanza 43 especies y 24 géneros, de las cuales 33 (en 20 géneros se conocen para la Argentina.The current knowledge of the Patagonian Ephemeroptera is due to the original and compiling work by M.L. Pescador, W.L. Peters and E. Domínguez during last Century's 80´s . Besides, other previous publications exist that contributed to achieve a reasonable knowledge of its taxonomy for the norhtern and central Patagonian Andes, though poor for the southernmost mountain areas (Santa Cruz and Tierra del Fuego provinces and the steppe. From the field work carried in 80 collecting sites during the development of the "Darwin Initiative Project" in the Nahuel Huapi Nacional Park, some species are recorded for the first time in Argentina (Hapsiphlebia anastomosis Demoulin, the Andean region (Apobaetis Day and the province of Río Negro (Chaquihua bullock (Navás, Andesiops ardua (Lugo-Ortíz & McCafferty, Murphyella needhami Lestage, Dactylophlebia carnulenta Pescador & Peters. With

  12. Age and composition of granulite xenoliths from Paso de Indios, Chubut province, Argentina

    Science.gov (United States)

    Castro, Antonio; Aragón, Eugenio; Díaz-Alvarado, Juan; Blanco, Idael; García-Casco, Antonio; Vogt, Katharina; Liu, D.-Y.

    2011-12-01

    Granulite xenoliths enclosed in Paleogene alkali basalts from the locality of Paso de Indios in The Argentinean Patagonia, have been studied for petrology, geochemistry and U-Pb SHRIMP zircon geochronology. These are lower crust xenoliths composed of pyroxene and plagioclase dominantly. Symplectitic overgrowths with olivine and new pyroxene-plagioclase formation around the large pyroxene crystals are common. The study of phase equilibrium yields a decompression path from pressure 0.9 GPa at temperatures of about 1000 °C. The major element composition does not correspond with any known basaltic or andesitic magmas. They have SiO 2 residual origin of the granulites. In situ age determination with SHRIMP yields a Concordia age of 175.9 ± 4.9 Ma with MSWD = 1.4. This age represent the time of complex lithosphere evolution in relation with the formation of this residual crust.

  13. Estratigrafía, análisis de facies y paleoambientes de la formación cañadón asfalto en el depocentro jurásico cerro Cóndor, provincia del Chubut

    Directory of Open Access Journals (Sweden)

    Nora Cabaleri

    2010-05-01

    Full Text Available El depocentro Cerro Cóndor representa la secuencia estratigráfica del Jurásico continental más completa de la cuenca de Cañadón Asfalto y de Sudamérica austral. Se sitúa en la Patagonia extraandina, en ambas márgenes del río Chubut medio. La sedimentación en esta cuenca pull apart, acompañada por efusiones de basalto olivínico, comenzó en el Jurásico Medio temprano. Predominan en la Formación Cañadón Asfalto los depósitos lacustres caracterizados por asociaciones de facies carbonáticas y siliciclásticas intercaladas con rocas lávicas en la base y depósitos piroclásticos hacia el techo de la unidad. Se describe el desarrollo de facies a lo largo de un corte norte-sur que abarca las secciones de estancia El Torito y de los cañadones Los Loros, Las Chacritas, Carrizal, Asfalto y Lahuincó. Las facies/microfacies carbonáticas están representadas por mudstones, wackestones,packstones, grainstones y calizas microbialíticas características de ambientes litorales, marginales y palustres. En la Formación Cañadón Asfalto se distinguen un miembro inferior (Las Chacritas, constituido por calizas, lutitas, areniscas y conglomerados, intercalados con basaltos olivínicos y por otro superior (Puesto Almada compuesto por tobas, tufitas, lutitas y areniscas. El primero es portador de una asociación palinológica de edad bajociano-bathoniana y el segundo de dinosaurios de edad tithoniana. Se describen detalladamente e ilustran las secciones estratigráficas de ambos miembros de la formación en sus localidades tipo, cañadón Las Chacritas y estancia el Torito y se reconstruyen los paleoambientes del depocentro desde el Aaleniano al Tithoniano. La edad del miembro Puesto Almada en su localidad tipo se obtuvo mediante una datación radimétrica (K/Ar de biotitas provenientes de una delgada capa de toba volcánica (147,1 ± 3,3 Ma, Tithoniano proveniente de la parte superior de la unidad.

  14. Wind regime and wind power in North Patagonia, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Palese, C.; Laessig, J.L.; Cogliati, M.G.; Bastanski, M.A. [Universidad Nacional del Comahue, Buenos Aires (Argentina). Facultad de Ingenieria

    2000-07-01

    The present paper discusses wind and wind power characteristics in a region north of 40{sup o}S (North Patagonia, Argentina) as well as wind power projects sustainability. Extreme wind episodes influence most economic and social regional activities. Mean flow pattern was studied in three North Patagonia sites: Neuquen, Mari Menuco and Cutral-Co, by sampling analysis of wind direction and intensity during a year. Gusts were quantified and strong winds were studied. Available meteorological power was also estimated. It was observed that North Patagonia is a place of great wind power potential. However, the energy available, which is related to prevailing strong winds, is also associated to high gust occurrence which certainly restricts exploitation. (Author)

  15. La extensa zona de deslizamientos de la escarpa oriental de la Pampa de Salamanca, Chubut, entre los 45°00´S y 45°45´S The extensive zone of slides on the eastern erosion scarp of Pampa de Salamanca, Chubut

    Directory of Open Access Journals (Sweden)

    E.F. González Díaz

    2004-12-01

    Full Text Available Durante la ejecución del mapa geomorfológico de la provincia del Chubut, se identificó entre las latitudes de los 45°00´S y 45°45´S y a lo largo de unos 70-75 km, una extensa faja de deslizamientos adyacente y prácticamente paralela a la escarpa oriental de la Pampa de Salamanca. Los deslizamientos, con marcado predominio de deslizamientos rotacionales, perturban el tramo superior de la secuencia sedimentaria terciaria. En los niveles arcillosos de la Formación Chenque (= Formación Patagonia, se localizarían las superficies de despegue o corte (shear para su ocurrencia. Diferencias entre sus rasgos morfológicos, tipológicos y el promotor sugerido permiten proponer cuatro zonas (I, II, III y IV de deslizamientos. La tipología aquí propuesta es provisoria, siendo sólo una base de futuras elaboraciones. Cronológicamente se diferenciaron dos conjuntos de deslizamientos: unos antiguos, más extensos y de mayor volumen, con marcadas evidencias de erosión y aquellos modernos, más reducidos, que con excelente conservación de su morfología primaria, son producto de posteriores removilizaciones acontecidas en sectores de los antiguos, que se expresan esencialmente bajo la forma de flujos (corrientes de tierra o earthflows y más ocasionalmente como deslizamientos rotacionales secundarios (slumps. Entre los de mayor edad, los de la zona I, son definidos como afines en general a un deslizamiento rotacional con una fase distal de flujo; ocasionalmente habrían superado los límites del actual acantilado marino. A pesar de esta primera apreciación, no se descarta su consideración como ejemplos de expansiones laterales (lateral spreads. Los de la zona II, son definidos como deslizamientos rotacionales múltiples retrogradantes. Aquellos de la zona III integran un conjunto de deslizamientos con un marcado control estructural (N50°E, en sus desprendimientos. La zona IV, compone una estrecha y continua faja adyacente a la Pampa de

  16. Análisis de sistema de conversores fluido-dinámicos de energía renovable para la Patagonia Austral de Argentina

    Directory of Open Access Journals (Sweden)

    Carlos Victor Manuel Labriola

    2014-06-01

    Full Text Available El potencial de energía en mares y océanos se puede clasificar de distintas formas, por ejemplo: * La energía de las mareas ó Mareomotriz * La energía de las corrientes marinas * La energía de las olas ó Undimotriz * La energía térmica oceánica (OTEC. De estas formas de energía oceánica, tres son posibles en la zona Atlántica de nuestra Patagonia Austral, la Mareomotriz, la Undimotriz y la de corrientes marinas. La Energía Mareomotriz se da desde Viedma hasta Tierra del Fuego con amplitudes de mareas de 4m hasta 20m, la Energía de las Olas se da en la costa de Chubut y Santa Cruz con potenciales de 10 a 30kW/m lineal de frente de ola y el aprovechamiento de las corrientes marinas se puede dar en lugares puntuales como ser la desembocadura del río Deseado o la de Río Gallegos. Para estas Fuentes de Energía se está realizando un banco de pruebas de modelos conversores de las mismas a Energía Eléctrica, en la Unidad Académica Caleta Olivia (UACO de la Universidad Nacional de la Patagonia Austral (UNPA. Este banco dispondrá de dos canales de ensayos hidrodinámicos uno para energía de las corrientes marinas y otro para las olas. El primero dispondrá de una bomba de circulación con velocidad de fluido variable entre 0 y 4m/s. El banco para olas tendrá un sistema de batido del agua para producir ondas de amplitud y período variable. Además se están dimensionando dos modelos de conversores de energía oceánica. Uno es una turbina, tipo eólica sumergida y el otro modelo es de tubo electromecánico oscilante como conversor energético de las olas.

  17. Sedimentology and paleoenvironments of the Las Chacritas carbonate paleolake, Cañadón Asfalto Formation (Jurassic), Patagonia, Argentina

    Science.gov (United States)

    Cabaleri, Nora G.; Benavente, Cecilia A.

    2013-02-01

    The Las Chacritas Member is the lower part of the Cañadón Asfalto Formation (Jurassic). The unit is a completely continental limestone succession with volcanic contributions that were deposited during the development of the Cañadón Asfalto Rift Basin (Chubut province, Patagonia, Argentina). A detailed sedimentological analysis was performed in the Fossati depocenter to determine the paleoenvironments that developed in the context of this rift. The Las Chacritas Member represents a carbonate paleolake system with ramp-shaped margins associated with wetlands that were eventually affected by subaerial exposure and pedogenesis. This process is represented by three main subenvironments: a) a lacustrine setting sensu stricto (lacustrine limestone facies association), represented by Mudstones/Wackestones containing porifera spicules (F1), Intraclastic packstones (F6) and Tabular stromatolites (F10) in which deposition and diagenesis were entirely subaqueous; b) a palustrine setting (palustrine limestone facies association) containing Microbial Mudstones (F2), Intraclastic sandy packstone with ostracode remains (F3), Oncolitic packstone (F5), Brecciated limestone (F7) and Nodular-Mottled limestone (F8) representing shallow marginal areas affected by groundwater fluctuations and minor subaerial exposure; and c) a pedogenic paleoenvironment (pedogenic limestone facies association) including Intraclastic limestone (F4) and Packstones containing Microcodium (F9) facies displaying the major features of subaerial exposure, pedogenic diagenesis and the development of paleosols. The fluvial-palustrine-lacustrine succession shows a general shallow upward trend in which contraction-expansion cycles are represented (delimited by exposure and surface erosion). The variations in the successive formations reflect the responses to fluctuations in a combination of two major controls, the tectonic and local climatic variables. The predominance of the palustrine facies associations was

  18. DE GESTAS, DE SALVAJES Y DE MÁRTIRES. EL RELATO MAESTRO SOBRE EL FUERTE SAN JOSÉ RECONSIDERADO DESDE LA ARQUEOLOGÍA HISTÓRICA (PENÍNSULA VALDÉS, PCIA. DE CHUBUT, SIGLO XVIII / Savages, Epics and Martyrs. The Master Narrative about San Jose Fort reconside

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    Marcia Bianchi Villelli

    2015-06-01

    Full Text Available Desde inicios del siglo XX hasta el presente, la historiografía tradicional argentina se ha ocupado de estudiar la colonización española de costa patagónica de fines del siglo XVIII. La perspectiva desarrollada hasta 1980 se vinculaba principalmente a ámbitos conservadores de la historia que generaron una imagen fuertemente eurocéntrica y colonialista tanto del proceso de poblamiento como de cada uno de los tres asentamientos instalados sobre la costa patagónica entre 1779 y 1780 (el Fuerte Nuestra Señora del Carmen -Carmen de Patagones, Pcia. de Buenos Aires-, la Nueva Colonia y Fuerte de Floridablanca -Puerto San Julián, Pcia. de Santa Cruz- y el Fuerte San José -Península Valdés, Pcia. de Chubut.A partir de nuevas investigaciones realizadas en el Fuerte San José, el presente trabajo discutelas aproximaciones históricas tradicionales al mismo. Desde una perspectiva descolonial, se busca mostrar cómo el relato maestro historiográfico es solidario con la construcción del estado nación argentino, apoyándose en una mirada retrospectiva para legitimar su profundidad temporal y extensión espacial. De este modo, proponemos desde la arqueología histórica exponer la materialidad de nuevas tramas de sentidos para comprender proceso colonial en Patagonia, visibilizando otros espacios, actores, procesos y materialidades que habían quedado desdibujados en el relato maestro de la historiografía provincial y nacional.   Abstract  From the beginnings of the twentieth century up to present day, Argentinian traditional historiography has studied the late eighteenth century Spanish colonization of the Patagonian coast. The viewpoint developed until 1980 was mainly linked to conservative environmentsof historythat generated a strong Eurocentric and colonialist image of both, the process of settlement andof each of the three installed settlements on the Patagonian coast between 1779 and 1780 (Nuestra Señora del Carmen Fort -Carmen de

  19. Indigenous identity and textiles: an economic policy strategies in the province of Chubut La identidad indígena y sus textiles: estrategias de una política económica en la provincia de Chubut

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    Patricia María Méndez

    2010-01-01

    Full Text Available From the conception of the identity of individuals and of the groups as an elaboration, arises that the current indigenous identity employed by the state in the province of Chubut is functional to a policy which aims to prevent the emigration of the few people in rural areas of the province. It affirms that such a strategy is not new and that in the past other versions of this identity have also been useful to legitimate power projects. Through ethnographic and historical work, we explore some physical and social characteristics of rural areas of that province, some provincial regulations of government agencies, and certain attributes, preterits and present, of the indigenous identity employed by the state and of one of its symbols, Mapuche tissues. Laterally it refers in what way this identity is considered by some identified.A partir de la concepción de la identidad de las personas y de los grupos como una elaboración, se plantea que la actual identidad indígena empleada por el Estado en la provincia de Chubut resulta funcional a una política que pretende evitar la emigración de los escasos pobladores de las zonas rurales de la provincia. Se afirma que tal estrategia no es novedosa y que en el pasado otras versiones de esa identidad también han resultado útiles a los proyectos del poder legítimo. Mediante un trabajo etnográfico e histórico, se analizan algunas características físicas y sociales de la zona rural de esa provincia, algunas normativas de organismos gubernamentales provinciales, y ciertos atributos pretéritos y actuales de la identidad indígena empleada por el Estado y de uno de sus símbolos, los tejidos mapuches. Lateralmente se refiere de qué manera esa identidad es considerada por algunos identificados.

  20. Anomalías magnéticas en la Caldera Piedra Parada, Patagonia, Argentina

    OpenAIRE

    Aragón, Eugenio; Pinotti, Lucio; D´Eramo, Fernando Javier; GÓMEZ-ORTIZ, DAVID; Tejero López, Rosa; Tubia, José María; Cavarozzi, Claudia Ernestina; Aguilera, Yolanda Emilia; Ribot, Alejandro Mario; Gianibelli, Julio; Chernicoff, Carlos Jorge

    2009-01-01

    La caldera de Piedra Parada constituye el principal edificio volcánico del Complejo Volcánico Piroclástico del curso medio del río Chubut, situado en la provincia argentina de Chubut. Los materiales intracaldera están constituidos por coladas riolíticas, sills andesíticos, domos riolíticos y tobas de composición riolítica. Con objeto de investigar la estructura de la caldera, se han obtenido tanto datos magnéticos terrestres como aeromagnéticos. Los mapas magnéticos muestran que la caldera se...

  1. HOTELES DE TRELEW (CHUBUT, ARGENTINA HACIA EL DESARROLLO SUSTENTABLE DE LA ACTIVIDAD CON RESPONSABILIDAD SOCIAL

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    Ana M. Gómez

    2008-12-01

    Full Text Available El trabajo se enmarca en el Proyecto de Investigación “Hotelería Sustentable en la Ciudad de Trelew, Provincia del Chubut, República Argentina” cuyo objetivo general es diseñar un sistema de Administración para la hotelería de Trelew, que viabilice su gestión en el marco del desarrollo sustentable de la actividad hotelera. Como hipótesis de trabajo se supuso que la hotelería estaría en condiciones de tener una gestión sustentable cuando demostrara poseer una cultura empresarial dirigida al desarrollo sustentable, llevando a cabo una actividad económica viable, con equidad social y respeto a los recursos naturales, culturales y de biodiversidad; es decir, con Responsabilidad Social Empresarial. Combinando la metodología de encuesta con la de entrevista en profundidad se abordó a la totalidad de los propietarios/administradores de los hoteles de la ciudad, sumando un total de diez. En la entrevista, además de recabar valiosa información por parte de los entrevistados, se les proporcionó un cuestionario que contenía preguntas pertinentes para la elaboración de indicadores de impacto. De los entregados fueron devueltos nueve cuestionarios, redefiniéndose de esta manera el universo a analizar. Los datos fueron trabajados en primer lugar en forma unidimensional, para detectar las categorías de mayor frecuencia de respuesta y se rescataron los resultados más significativos. Luego, dada la cantidad de indicadores involucrados (alrededor de 70 preguntas en el cuestionario, se hizo un estudio multidimensional con una técnica de escalonamiento multidimensional: la de componentes principales. Con este procedimiento estadístico se logra un índice de nivel de compromiso hacia el desarrollo sustentable de la actividad, que permite realizar un análisis comparativo entre los hoteles participantes. Por otra parte, la Provincia del Chubut categoriza a los hoteles desde 1980 de acuerdo a la infraestructura y comodidades ofrecidas. Hoy

  2. Parasites in rodent coprolites from the historical archaeological site Alero Mazquiarán, Chubut Province, Argentina

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    Norma Haydée Sardella

    2009-02-01

    Full Text Available The aim of this study was to examine the parasitic remains that were found in rodent coprolites collected from the archaeological site Alero Mazquiarán (Chubut Province, 45º44'15"S, 70°25'9"W, which is assigned to the interface of the Araucanian and Tehuelche cultures, dated at 212 ± 35 years B.P. The faecal material from two unidentified rodent species (X-10 and X-11 was collected from one human pelvic cavity found in a multiple burial. The faecal samples were processed and examined using paleoparasitological procedures. The X-10 coprolites were positive for eggs of Monoecocestus sp. (Cestoda: Anoplocephalidae and the X-11 faeces were positive for Pterygodermatites sp. (Nematoda: Rictulariidae, Trichosomoides sp. (Nematoda: Trichosomoididae and Monoecocestus sp. In this study, we discuss parasitic life cycles, the zoonotic importance of parasites and the behaviour of the aboriginal people.

  3. Parasites in rodent coprolites from the historical archaeological site Alero Mazquiarán, Chubut Province, Argentina.

    Science.gov (United States)

    Haydée Sardella, Norma; Horacio Fugassa, Martín

    2009-02-01

    The aim of this study was to examine the parasitic remains that were found in rodent coprolites collected from the archaeological site Alero Mazquiarán (Chubut Province, 45 degrees 44'15''S, 70 degrees 25'9''W), which is assigned to the interface of the Araucanian and Tehuelche cultures, dated at 212 +/- 35 years B.P. The faecal material from two unidentified rodent species (X-10 and X-11) was collected from one human pelvic cavity found in a multiple burial. The faecal samples were processed and examined using paleoparasitological procedures. The X-10 coprolites were positive for eggs of Monoecocestus sp. (Cestoda: Anoplocephalidae) and the X-11 faeces were positive for Pterygodermatites sp. (Nematoda: Rictulariidae), Trichosomoides sp. (Nematoda: Trichosomoididae) and Monoecocestus sp. In this study, we discuss parasitic life cycles, the zoonotic importance of parasites and the behaviour of the aboriginal people.

  4. Last millenium environmental changes in Lake Bertrand sediments, Chilean Patagonia

    Science.gov (United States)

    Sacré, V.; Fagel, N.; Schmidt, S.; Alvarez, D.; Araneda, A.; Urrutia, R.

    2012-04-01

    Our study focuses on a multiproxy analysis of sedimentary records from Lago Bertrand (area 50 km2; 227 masl; 46°55'S 72°50'W). Three cores were retrieved during fieldtrips in 2009 and 2011 with an Uwitec gravity corer. One core was collected in the main lake (LBt09, 102 cm) and two others in a lateral extension (LBb11-A, 162 cm and LBb11-B, 156 cm). Data 210Pb and 137Cs give average sedimentation rates of 2 mm/yr for the upper core section from the main lake, allowing a decennial resolution. Our aim is to document the climatic variability during the last millennium in Northern Patagonia and its impact on the environment. Lago Bertrand is separated from a pro-glacial lake (Lago Plomo) by a morainic barrier. The sediments of this lake are mainly composed of clayed silts and very few sandy silts. In the cores from the Eastern branch of Lago Bertrand, X-ray radiographies and magnetic susceptibility profiles evidence well-defined pluri-millimetric laminations with organic-rich layers, especially in the central core section. In the main lake, X-ray radiographies show diffuse pluri-millimetric laminations while magnetic susceptibility profiles do not confirm it. The sediments of the main lake appear more homogeneous with less organic-rich layers. They are characterized by low C/N ratio (10), supporting an important aquatic productivity; high inorganic content (90-95% of the bulk sediment); two peaks in the biological silica profile; and abundant diatoms (50-100 µm). According to the age model, the changes in aquatic productivity occurred between 1700 and 1850 AD. The cores from the Eastern branch of Lago Bertrand are under investigation to confirm the extension of the sedimentological changes observed in the main lake. The main sedimentological change observed in Lago Bertrand occurs during an interval equivalent to a part of the Little Ice Age. A similar biogenic silica-rich layer was also recorded in another relatively distant lake (Lago Thompson at 45°30'S, 72°47

  5. Airborne laser altimetry survey of Glaciar Tyndall, Patagonia

    DEFF Research Database (Denmark)

    Keller, K.; Casassa, G.; Rivera, A.

    2007-01-01

    flown over the ablation area of Glaciar Tyndall, with 5 longitudinal tracks with a mean swath width of 300 m, which results in a point spacing of approximately 2 m both along and across track. A digital elevation model (DEM) generated using the laser altimetry data was compared with a DEM produced from...... of - 3.2 m a(-1) [Raymond, C., Neumann, T.A., Rignot, E., Echelmeyer, K.A., Rivera, A., Casassa, G., 2005. Retreat of Tyndall Glacier, Patagonia, over the last half century. Journal of Glaciology 173 (51), 239-247.]. A good agreement was also found between ice elevation changes measured with laser data...... and previous results obtained with Shuttle Radar Topography Mission (SRTM) data. We conclude that airborne laser altimetry is an effective means for accurately detecting glacier elevation changes in Patagonia, where an ice thinning acceleration trend has been observed during recent years, presumably...

  6. Estado actual del conocimiento del orden Odonata en la Patagonia

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    Javier MUZÓN

    2009-01-01

    Full Text Available El orden Odonata se encuentra representado en la Patagonia por 36 especies, reunidas en nueve familias y 18 géneros. El nivel de endemismo de esta taxocoenosis es alto, aproximadamente el 60% de las especies y casi el 40% de los géneros endémicos. La riqueza específica en la Patagonia decrece de Oeste a Este y de Norte a Sur, las áreas de mayor riqueza resultan ser las cordilleras de Nahuel Buta (Chile y de los Andes entre 38° y 41° S, y la meseta de Somuncurá (Argentina en la estepa. Se brinda una actualización del estado de conocimiento y un análisis de los principalespatrones de distribución.

  7. Diplodon shells from Northwest Patagonia as continental proxy archives: Oxygen isotopic results and sclerochronological analyses

    Science.gov (United States)

    Soldati, A. L.; Beierlein, L.; Jacob, D. E.

    2009-04-01

    Freshwater mussels of the genus Diplodon (Bivalvia, Hyriidae) are the most abundant bivalve (today and in the past) in freshwater bodies at both sides of the South-Andean Cordillera. There are about 25 different Diplodon genera in Argentina and Chile that could be assigned almost completely to the species Diplodon chilensis (Gray, 1828) and two subspecies: D. ch. chilensis and D. ch. patagonicus; this latter species is found in Argentina between Mendoza (32˚ 52' S; 68˚ 51' W) and Chubut (45˚ 51' S; 67˚ 28' W), including the lakes and rivers of the target area, the Nahuel Huapi National Park (Castellanos, 1960). Despite their wide geographic distribution, Diplodon species have only rarely been used as climate archives in the southern hemisphere. Kaandorp et al. (2005) demonstrated for Diplodon longulus (Conrad 1874) collected from the Peruvian Amazonas that oxygen isotopic patterns in the shells could be used in order to reconstruct the precipitation regime and dry/wet seasonal of the monsoonal system in Amazonia. Although this study demonstrated the potential of Diplodon in climatological and ecological reconstructions in the southern hemisphere, as of yet, no systematic study of Diplodon as a multi-proxy archive has been undertaken for the Patagonian region. In this work we present sclerochronological analyses supported by ^18Oshell in recent mussel of Diplodon chilensis patagonicus (D'Orbigny, 1835) collected at Laguna El Trébol (42°S-71°W, Patagonia Argentina), one of the best studied water bodies in the region for paleoclimate analysis. Water temperature was measured every six hours for one year using a temperature sensor (Starmon mini®) placed at 5m depth in the lake, close to a mussel bank. Additionally, ^18Owater was measured monthly for the same time range.g^18Oshell values obtained by micro-milling at high spatial resolution in the growth increments of three Diplodon shells were compared to these records, and to air temperature and

  8. The impact of Chilean migration on employment in Patagonia.

    Science.gov (United States)

    Cariola Sanz, L

    1989-06-01

    This paper discusses the employment situation of Chilean migrant workers, their impact on labor markets in Patagonia, Argentina, and the government's past and projected responses to this phenomenon. In 1980, Chilean inhabitants of patagonia comprised 11% of the area's population. Chilean migration to patagonia was closely linked to economic activities that began to flourish in the 20th century, such as livestock raising, fruit and vegetable cultivation, and mining for coal and petroleum. No Chilean migrants work in a wide range of sectors. In Patagonia's southern provinces availability and ability to withstand rigorous climate conditions are the main factors which account for the prevalence of Chilean manpower. Chilean migrants do not in general displace local manpower. Legislation and the permeability of the border ensure that most workers enter the country as tourists. Clandestine migration is not an issue. Illegal migrants have provoked negative reactions for several reasons: 1) they comprise a marginal population without formal citizenship; 2) being employed as clandestine workers, they pay no social security, nor do their employers; 3) being illegal, they are obliged to accept lower wages and inferior working conditions which creates unfair competition within labor markets; and 4) as a result of these conditions, xenophobic and endophobic attitudes in relations with Argentine nationalists are reinforced. The government has attempted to solve these problems through various measures. Beginning in 1934, most foreigners entered Argentina with a tourist visa, becoming illegal when they stayed beyond authorized limits. Several measures over the years provided amnesty to illegal migrants. Currently, the law promotes immigration, monitors the admission of foreigners to the country and stipulates their rights and obligations. The law lists 115 articles on immigration promotion and on regulation of the movements of foreigners. Because of the present economic crisis in

  9. Cenozoic back-arc magmatism of the southern extra-Andean Patagonia (44° 30' - 52° S: A review of geochemical data and geodynamic interpretations

    Directory of Open Access Journals (Sweden)

    M. D'Orazio

    2004-12-01

    Full Text Available Huge amounts of basaltic s.l. lavas were persistently erupted along the eastern side of the Andean Cordillera, throughout Cenozoic time, forming extensive plateaus, hundreds of monogenetic scoria cones and other volcanic structures in a continental back-arc setting. The igneous products exposed in the southern sector of the extra-Andean Patagonia (44° 30' - 52° S are dominantly mafic with minor slightly evolved compositions and rare highly differentiated products. The many published chemical analyses of these rocks, indicate that the mafic lavas range from strongly silica - undersaturated basanites to oversaturated basaltic andesites, and that most of the lavas have a typical within-plate geochemical signature. However, a number of lavas, generally erupted in the western-central sectors of Patagonia, are characterized by different distributions of the incompatible elements with high LILE/HFSE and LREE/HFSE ratios. The REE distribution modelling suggests a low degree of melting of a deep (> 70 km garnet-bearing source for the alkaline magmas, and a higher degree of melting of the same source, or an even higher degree of melting of an enriched source, for the subalkaline magmas. The available Sr-Nd-Pb isotope compositions clearly attest to a major geographic variation: the southernmost lavas have lower 87Sr/86Sr and higher 143Nd/144Nd and 206Pb/204Pb ratios with respect to those erupted to the north. On the whole, the Sr-Nd-Pb isotope compositions of the southern Patagonia lavas fall within the typical range of within-plate continental magmas; in addition the Pb isotope ratios fall in the range of the Southern Hemisphere Dupal Pb isotope anomaly. The geochemical variations of the southern Patagonia lavas are discussed in terms of different geochemical components: depleted and enriched sub-slab asthenosphere, enriched continental lithospheric mantle, continental crust and subducted materials. The geodynamic significance is interpreted with in the

  10. Estado de conocimiento del orden Ephemeroptera en la Patagonia

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    Pablo PESSACQ

    2009-01-01

    Full Text Available El conocimiento actual del orden Ephemeroptera en la Patagonia se debe en gran parte a la labor original y compilatoria de M.L. Pescador, W.L. Peters y E. Domínguez, llevada a cabo en la década del 80 del siglo pasado. Se suman a ésta, importantes contribuciones que han conducido a un adecuado conocimiento del grupo en la cordillera norte y centro de la Patagonia, aunque menor en la zona austral de esta región (Santa Cruz y Tierra del Fuego y las áreas de estepa. Merced al trabajo de campo realizado en 80 sitios de muestreo relevados en el marco del “Darwin Initiative Project” en el Parque Nacional Nahuel Huapi, se incluyen aquí nuevos registros para la Argentina (Hapsiphlebia anastomosis Demoulin, la región Andina (Apobaetis Day y la provincia de Río Negro (Chaquihua bullocki (Navás, Andesiops ardua (Lugo-Ortíz & McCafferty, Murphyella needhami Lestage y Dactylophlebia carnulenta Pescador & Peters. Con estos registros, la riqueza de Ephemeroptera de la Patagonia alcanza 43 especies y 24 géneros, de las cuales 33 (en 20 géneros se conocen para la Argentina.

  11. Estado de conocimiento del orden Plecoptera en la Patagonia

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    PESSACQ Pablo

    2009-01-01

    Full Text Available El conocimiento actual del orden Ephemeroptera en la Patagonia se debe en gran parte a la labor original y compilatoria de M.L. Pescador, W.L. Peters y E. Domínguez, llevada a cabo en la década del 80 del siglo pasado. Se suman a ésta, importantes contribuciones que han conducido a un adecuado conocimiento del grupo en la cordillera norte y centro de la Patagonia, aunque menor en la zona austral de esta región (Santa Cruz y Tierra del Fuego y las áreas de estepa. Merced al trabajo de campo realizado en 80 sitios de muestreo relevados en el marco del “Darwin Initiative Project” en el Parque Nacional Nahuel Huapi, se incluyen aquí nuevos registros para la Argentina (Hapsiphlebia anastomosis Demoulin, la región Andina (Apobaetis Day y la provincia de Río Negro (Chaquihua bullocki (Navás, Andesiops ardua (Lugo-Ortíz & McCafferty, Murphyella needhami Lestage y Dactylophlebia carnulenta Pescador & Peters. Con estos registros, la riqueza de Ephemeroptera de la Patagonia alcanza 43 especies y 24 géneros, de las cuales 33 (en 20 géneros se conocen para la Argentina.

  12. Glaciares de escombros fósiles en el cordón Leleque, Noroeste del Chubut: significado paleoclimático y paleográfico

    Directory of Open Access Journals (Sweden)

    Lucas Ruiz

    2012-09-01

    Full Text Available Este trabajo analiza la relación actual y pasada del ambiente periglacial y glaciario en los Andes de la Patagonia norte (41°- 43° L.S.. Es la primera vez que un estudio de estas características es llevado a cabo en esta región. A partir del análisis y caracterización de geoformas relacionadas con el permafrost de montaña y el ambiente glaciario, el análisis de las condiciones climáticas y el uso de análogos actuales, se presenta una reconstrucción paleogeográfica y paleoclimática del Cordón Leleque. El Cordón del Plata, en los Andes Centrales, con glaciares convencionales y glaciares de escombros, se utiliza como análogo actual de las condiciones pasadas en el Cordón Leleque. A partir de la ubicación espacial de las diferentes geoformas reconocidas en el Cordón Leleque se reconocieron cuatro grupos. Utilizando la relación entre la altura de la línea de equilibrio regional y la altura del límite de permafrost de montaña, se derivaron las variaciones climáticas necesarias que pudieron generar los diferentes grupos. Estos resultados son comparados con trabajos previos.

  13. El patrimonio industrial petrolero en la Patagonia: Comodoro Rivadavia (Argentina y Cerro Sombrero (Chile. Una perspectiva comparada

    Directory of Open Access Journals (Sweden)

    Pía Acevedo Méndez

    2016-01-01

    Full Text Available El hallazgo de petróleo en Comodoro Rivadavia (Chubut, Argentina y en Manantiales (Tierra del Fuego, lado chileno, motivó la construcción de espacios socioproductivos bajo el modelo de Company Towns. En el caso argentino la empresa estatal Yacimientos Petrolíferos Fiscales (Y.P.F creó el Campamento Central y la Empresa Nacional del Petróleo (ENAP creó Cerro Sombrero en Chile, los que en la década de 1970 formaron dos tejidos urbanos (barrio en el caso argentino y pueblo en el caso chileno. En esta dinámica se transformó el modo de habitar de ambos espacios, que se convirtieron en potenciales elementos turísticos, teniendo en cuenta que desde el año 2014 poseen reconocimiento patrimonial relacionado con su pasado petrolero y su arquitectura moderna. El objetivo es comparar cómo ambas empresas petroleras estatales construyeron dichos espacios “urbanos” y sus comunidades sociolaborales e indagar en la relación identidad/ patrimonio de ypefeanos y enapinos.

  14. CARACTERIZACIÓN SOCIO-AMBIENTAL DE UN PAISAJE TRANSFORMADO: EL CASO DE LA LAGUNA NEGRA.TRELEW. CHUBUT. ARGENTINA

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    Gladys Alcarraz

    2008-12-01

    Full Text Available La ciudad de Trelew se encuentra en la Provincia del Chubut, departamento Rawson, a los 43o 14' de Latitud Sur y 65o 19' de Longitud Oeste, su Ejido Municipal cubre una superficie total de 248 km2. Aproximadamente el 70% de los líquidos cloacales domiciliarios y pluviales de la ciudad de Trelew, son vertidos desde principios de la década del 70’ a un sistema lagunar. Originalmente estas lagunas eran cuencas naturales, algunas permanentes y otras temporarias, alimentadas por aguas subterráneas y por precipitaciones. Los bajos, hoy convertidos en lagunas permanentes, hidrológicamente representaban áreas de descarga -evaporación- alimentadas por los aportes de cañadones que drenan desde la terraza intermedia y el valle o bien por crecientes y desbordes del Río Chubut. Hoy el proceso se ha revertido, y las lagunas aportan agua en forma constante al sistema freático, habiéndose convertido entonces, en áreas de recarga -infiltración-, con consecuencias ambientales, paisajísticas y sociales. El objetivo del presente trabajo fue determinar la variación multitemporal de las lagunas de estabilización de la ciudad de Trelew, desde los años 1969 a 2005 para estimar las consecuencias producidas en el paisaje y caracterizar social y económicamente la población aledaña a las lagunas. Metodológicamente, para caracterizar el área de estudio y realizar una evolución de la misma desde las características originales hasta la actualidad se utilizó la teledetección y un relevamiento censal a campo con aplicación de encuestas y observación directa. La población aledaña a las lagunas presenta características particulares en cuanto a las actividades económicas que desarrollan, las condiciones en las que viven y llevan adelante esas actividades, conformando “asentamientos aislados”, precarios, que le dan cierto carácter de espacio rural marginal, como categoría en el continuo rural-urbano. Cuando se cambian artificialmente las

  15. El volcanismo del complejo Marifil en Arroyo Verde, vertiente suroriental del Macizo de Somún Cura, Chubut

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    Marcelo J Márquez

    2010-05-01

    Full Text Available Se describen en este trabajo las facies volcánicas pertenecientes al Complejo Marifil que afloran en la localidad de Arroyo Verde, vertiente suroriental del macizo de Somún Cura, provincia del Chubut. Se discriminan facies de ignimbritas riolíticas, brechas piroclásticas, domos y domos vítreos traquíticos y diques riolíticos. Las relaciones de campo indican que las ignimbritas fueron el primer evento eruptivo que se alternaron con esporádicas coladas de bloques y cenizas. Luego se produjo la intrusión de las facies dómicas y por último la de los diques riolíticos. Las facies descriptas tienen composiciones que varían entre riolitas y traquitas con altos contenidos de K, característicos de las rocas pertenecientes a este complejo. Teniendo en cuenta las características observadas se propone un mecanismo fisural de erupción en esta localidad.

  16. La extensa zona de deslizamientos de la escarpa oriental de la Pampa de Salamanca, Chubut, entre los 45°00´S y 45°45´S

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    E.F. González Díaz

    2004-12-01

    Full Text Available Durante la ejecución del mapa geomorfológico de la provincia del Chubut, se identificó entre las latitudes de los 45°00´S y 45°45´S y a lo largo de unos 70-75 km, una extensa faja de deslizamientos adyacente y prácticamente paralela a la escarpa oriental de la Pampa de Salamanca. Los deslizamientos, con marcado predominio de deslizamientos rotacionales, perturban el tramo superior de la secuencia sedimentaria terciaria. En los niveles arcillosos de la Formación Chenque (= Formación Patagonia, se localizarían las superficies de despegue o corte (shear para su ocurrencia. Diferencias entre sus rasgos morfológicos, tipológicos y el promotor sugerido permiten proponer cuatro zonas (I, II, III y IV de deslizamientos. La tipología aquí propuesta es provisoria, siendo sólo una base de futuras elaboraciones. Cronológicamente se diferenciaron dos conjuntos de deslizamientos: unos antiguos, más extensos y de mayor volumen, con marcadas evidencias de erosión y aquellos modernos, más reducidos, que con excelente conservación de su morfología primaria, son producto de posteriores removilizaciones acontecidas en sectores de los antiguos, que se expresan esencialmente bajo la forma de flujos (corrientes de tierra o earthflows y más ocasionalmente como deslizamientos rotacionales secundarios (slumps. Entre los de mayor edad, los de la zona I, son definidos como afines en general a un deslizamiento rotacional con una fase distal de flujo; ocasionalmente habrían superado los límites del actual acantilado marino. A pesar de esta primera apreciación, no se descarta su consideración como ejemplos de expansiones laterales (lateral spreads. Los de la zona II, son definidos como deslizamientos rotacionales múltiples retrogradantes. Aquellos de la zona III integran un conjunto de deslizamientos con un marcado control estructural (N50°E, en sus desprendimientos. La zona IV, compone una estrecha y continua faja adyacente a la Pampa de

  17. Cenozoic diatreme field in Chubut (Argentina) as evidence of phreatomagmatic volcanism accompanied with extensive Patagonian plateau basalt volcanism?

    Institute of Scientific and Technical Information of China (English)

    Károly Németh; Ulrike Martin; Miguel J. Haller; Viviana L Alric

    2007-01-01

    @@ In Patagonia, Argentina, at the northern border of the Patagonian Cenozoic mafic plateau lava fields, newly discovered diatremes stand about 100 m above the surrounding plain. These diatremes document phreatomagmatic episodes associated with the formation of the volcanic fields. The identified pyroclastic and intrusive rocks are exposed lower diatremes of former phreatomagmatic volcanoes and their feeding dyke systems.These remotely located erosional remnants cut through Paleozoic granitoids and Jurassic/Cretaceous alternating siliciclastic continental successions that are relatively easily eroded. Plateau lava fields are generally located a few hundreds of metres above the highest level of the present tops of the preserved diatremes suggesting a complex erosional history and potential interrelation-ships between the newly identified diatremes and the surrounding lava fields. Uprising magma from theunderlying feeder dyke into the diatreme root zone intruded the clastic debris in the diatremes, inflated them and mingled with the debris to form subterranean peperite. The significance of identifying diatremes in Patagonia are twofold: 1) in the syn-eruptive paleoenvironment, water was available in various "soft-sediments", commonly porous, media aquifer sources, and 2) the identified abundant diatremes that form diatreme fields are good source candidates for the extensive lava fields with phreatomagmatism facilitating magma rise with effective opening of fissures before major lava effusions.

  18. Gondwanide continental collision and the origin of Patagonia

    Science.gov (United States)

    Pankhurst, R. J.; Rapela, C. W.; Fanning, C. M.; Má; rquez, M.

    2006-06-01

    A review of the post-Cambrian igneous, structural and metamorphic history of Patagonia, largely revealed by a five-year programme of U-Pb zircon dating (32 samples), geochemical and isotope analysis, results in a new Late Palaeozoic collision model as the probable cause of the Gondwanide fold belts of South America and South Africa. In the northeastern part of the North Patagonian Massif, Cambro-Ordovician metasediments with a Gondwana provenance are intruded by Mid Ordovician granites analogous to those of the Famatinian arc of NW Argentina; this area is interpreted as Gondwana continental crust at least from Devonian times, probably underlain by Neoproterozoic crystalline basement affected by both Pampean and Famatinian events, with a Cambrian rifting episode previously identified in the basement of the Sierra de la Ventana. In the Devonian (following collision of the Argentine Precordillera terrane to the north), the site of magmatism jumped to the western and southwestern margins of the North Patagonian Massif, although as yet the tectonics of this magmatic event are poorly constrained. This was followed by Early Carboniferous I-type granites representing a subduction-related magmatic are and Mid Carboniferous S-type granites representing crustal anatexis. The disposition of these rocks implies that the North Patagonian Massif was in the upper plate, with northeasterly subduction beneath Gondwana prior to the collision of a southern landmass represented by the Deseado Massif and its probable extension in southeastern Patagonia. This 'Deseado terrane' may have originally rifted off from a similar position during the Cambrian episode. Intense metamorphism and granite emplacement in the upper plate continued into the Early Permian. Known aspects of Late Palaeozoic sedimentation, metamorphism, and deformation in the Sierra de la Ventana and adjacent Cape Fold Belt of South Africa are encompassed within this model. It is also compatible with modern geophysical and

  19. Caracterización geológica del skarn "El Abuelo" Alto Río Senguerr, Chubut Geological characterization of "El Abuelo" skarn deposit, Alto Rio Senguerr, Chubut

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    M.E. Lanfranchini

    2004-12-01

    Full Text Available El skarn "El Abuelo" está situado en el extremo sudoccidental de la Provincia del Chubut, República Argentina. Se desarrolla en un ambiente tectónico de arco magmático, en corteza continental. Está emplazado en sedimentitas silicoclásticas con intercalaciones carbonáticas y se vincula a cuerpos intrusivos riodacíticos, conjunto atribuido al Cretácico inferior. En esta manifestación se reconocieron anomalías en elementos metalíferos (Fe, Cu, Pb, Zn, Ag que le confieren interés como guía para la exploración de recursos minerales en esta región. La presente contribución tiene por finalidad tipificar al skarn a través de una caracterización geológica y mineralógica. La asociación paragenética de minerales reconocidos permitió identificar dos episodios: uno metasomático y otro hidrotermal, ambos desarrollados en las sedimentitas (exoskarn. El primero fue originado por fluidos de derivación magmática, que provocaron la formación de minerales calcosilicáticos. Posteriormente la incorporación de agua en el sistema facilitó el desarrollo de minerales hidratados, retrogradando parcialmente al skarn, proceso que fue seguido por la depositación de hematita, magnetita y sulfuros, acompañados de sílice. La asociación de minerales calcosilicáticos, junto a la variación en la composición química de piroxenos y granates y la mineralización identificada, permiten tipificar al skarn "El Abuelo" como cálcico, con hierro como metal dominante."El Abuelo" skarn deposit is located in southwest Chubut province. It was formed in a magmatic arc tectonic environment, developed in continental crust. The skarn is hosted in low cretaceous silicoclastic sands interbedded with limestones, and it is related to small rhyodacitic sub-volcanic bodies. Anomalous contents of metals (Fe, Cu, Pb, Zn, Ag provide an interesting exploration guide. This paper is devoted to give a geological and a mineralogical characterization of the skarn, in order

  20. El volcanismo del complejo Marifil en Arroyo Verde, vertiente suroriental del Macizo de Somún Cura, Chubut The volcanism of the Marifil Complex in Arroyo Verde, Southeastern slope of the Somun Cura Massif, Chubut

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    Marcelo J Márquez

    2010-05-01

    Full Text Available Se describen en este trabajo las facies volcánicas pertenecientes al Complejo Marifil que afloran en la localidad de Arroyo Verde, vertiente suroriental del macizo de Somún Cura, provincia del Chubut. Se discriminan facies de ignimbritas riolíticas, brechas piroclásticas, domos y domos vítreos traquíticos y diques riolíticos. Las relaciones de campo indican que las ignimbritas fueron el primer evento eruptivo que se alternaron con esporádicas coladas de bloques y cenizas. Luego se produjo la intrusión de las facies dómicas y por último la de los diques riolíticos. Las facies descriptas tienen composiciones que varían entre riolitas y traquitas con altos contenidos de K, característicos de las rocas pertenecientes a este complejo. Teniendo en cuenta las características observadas se propone un mecanismo fisural de erupción en esta localidad.Marifil Complex volcanic facies that crop out in the locality of Arroyo Verde, SE slope of Macizo de Somún Cura, are described here. Rhyolitic ignimbrite facies, pyroclastic breccias, traquitic domes and vitreous domes, and rhyolitic dikes are distinguished. Field relationships point out the ignimbrites as the first effusive event. Some sporadically block and ash flows are intercalated within the ignimbrites. These deposits were intruded by domes; the latest event is represented by the intrusion of the rhyolitic dykes. Chemical composition of these rocks varies between high K rhyolites and traquites, which correspond to typical characteristics of the Marifil Complex rocks. The observations allow proposing a fissural mechanism of eruption for these facies in this locality.

  1. Angelaíta en la paragénesis del distrito Los Manantiales, provincia del Chubut: Una nueva especie mineral Angelaite in the paragenesis of Los Manantiales district, Chubut, Argentina: a new mineral species

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    M.K. de Brodtkorb

    2004-12-01

    Full Text Available Angelaíta, Cu2AgPbBiS2 , una nueva especie mineral, fue localizada en la mina Ángela, mineralización de tipo IS del distrito Los Manantiales, Chubut, Argentina. La paragénesis incluye esfalerita, pirita, calcopirita, galena y en menor cantidad arsenopirita, betekhtinita, bornita, matildita, oro, plata, electrum, telurio, cervelleíta y hematita. La galena presenta numerosas inclusiones de angelaíta, aikinita, wittichenita y miharaíta. Esta paragénesis se presenta en vetas asociada a diferentes rocas volcánicas de la Formación Lonco Trapial de edad jurásica. La composición química de angelaíta fue obtenida con una microsonda electrónica. Se presenta en granos anhedrales de 10-100mm, es de color gris verdoso, moderadamente pleocroica y anisótropa.Angelaíte Cu2AgPbBiS2, a new mineral species, occurs in Mina Ángela, an IS type mineralization at the Los Manantiales district. The assemblage contains sphalerite, pyrite, chalcopyrite, galena with numerous inclusions of angelaíte, aikinite, miharaíte, and in smaller amounts arsenopyrite, betekhtinite, bornite, matildite, gold, silver, electrum, tellurium cervelleíte and hematite. Galena presents numerous inclusions of angelaíta, aikinita, wittichenita y miharaíta. This paragenesis occurs in veins associated with different volcanic rocks of the jurassic Lonco Trapial Formation. Angelaíte was observed as anhedral grains of 10-100mm, greenish grey in colour, moderately pleochroic and anisotropic.

  2. Variation in external morphology of resident bottlenose dolphins (Tursiops truncatus) in Bahia San Antonio, Patagonia, Argentina.

    OpenAIRE

    Vermeulen, Els; Cammareri, Alejandro

    2010-01-01

    Two geographic variations of bottlenose dolphins were described in Argentina (Bastida & Rodriguez, 2003); bottlenose dolphins characterized by their triangular dorsal fin shape (coast of the province of Buenos Aires), and bottlenose dolphins characterized by their falcate dorsal fin shape (coast of the province of Chubut). It was stated that `their clear difference would indicate that both geographic forms are isolated¿ (Bastida & Rodriguez, 2003 p.137). A photo-identification study carrie...

  3. Chilenia y Patagonia: ¿un mismo continente a la deriva? Chilenia and Patagonia, the same continent adrift?

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    Renata Nela Tomezzoli

    2012-06-01

    Full Text Available La zona de estudio está ubicada a lo largo del margen sudoccidental del Gondwana y abarca desde las Sierras Australes hasta el Bloque de San Rafael y el Macizo Nordpatagónico. A partir de la integración de los datos obtenidos en trabajos de campo, estudios paleomagnéticos, de anisotropía de susceptibilidad magnética, e información obtenida por otros autores, se concluye en este trabajo que la deformación en esta región del Gondwana podría haber comenzado durante el Devónico Medio y se relacionaría con la colisión de Patagonia desde el sur y de Chilenia desde el oeste. Siendo que Chilenia y Patagonia habrían comenzado a colisionar con Gondwana al mismo tiempo, se plantea la posibilidad de que hayan sido parte de un mismo terreno alóctono a la deriva. Posteriormente, en el Carbonífero, colisionó desde el sur el Macizo del Deseado. La deformación post-colisional asociada a estos procesos habría continuado hasta el Pérmico, produciendo movimientos latitudinales, como parte del ajuste y acople final de los bloques continentales que configuraron la Pangea Triásica en conjunto con el núcleo cratónico principal del Gondwana.The study area is located along the southwestern margin of Gondwana, ranging from Sierra de la Ventana (Sierras Australes to the San Rafael Block and the North Patagonian Massif. From the integration of data from feld work, paleomagnetic studies, anisotropy of magnetic susceptibility, and information obtained by other authors in this paper is concluded that the deformation in this part of Gondwana may have begun during the Middle Devonian and would relate to the collision of Patagonia from the south and Chilenia from the west. Since Chilenia and Patagonia have begun to collide with Gondwana at the same time raises the possibility that they were part of the same allochthonous drif terrain. Later in the Carboniferous, from the south collided the Deseado Massif. The post-collisional deformation associated with

  4. Niche Segregation between Wild and Domestic Herbivores in Chilean Patagonia

    Science.gov (United States)

    Iranzo, Esperanza C.; Traba, Juan; Acebes, Pablo; González, Benito A.; Mata, Cristina; Estades, Cristián F.; Malo, Juan E.

    2013-01-01

    Competition arises when two co-occuring species share a limiting resource. Potential for competition is higher when species have coexisted for a short time, as it is the case for herbivores and livestock introduced in natural systems. Sheep, introduced in the late 19th century in Patagonia, bear a great resemblance in size and diet to the guanaco, the main native herbivore in Patagonia. In such circumstances, it could be expected that the two species compete and one of them could be displaced. We investigated spatial overlap and habitat selection by coexisting sheep and guanaco in winter and in summer. Additionally, we studied habitat selection of the guanaco in a control situation free from sheep, both in summer and winter. We also determined overlap between species in areas with different intensity of use (named preferred and marginal areas) in order to further detect the potential level of competition in the case of overlapping. Guanaco and sheep showed significantly different habitat preferences through all seasons, in spite of their spatial overlap at landscape scale. Additionally, the habitat used by guanaco was similar regardless of the presence or absence of livestock, which further indicates that sheep is not displacing guanaco where they coexist. These results suggest that habitat segregation between guanaco and sheep is due to a differential habitat selection and not to a competitive displacement process. Therefore, the potential for competition is considered low, contrary to what has been previously observed, although this could be a density-dependent result. PMID:23555656

  5. Late cretaceous aquatic plant world in Patagonia, Argentina.

    Science.gov (United States)

    Cúneo, N Rubén; Gandolfo, María A; Zamaloa, María C; Hermsen, Elizabeth

    2014-01-01

    In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla) and a monocot (Araceae). Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae). Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form) and the eudicot angiosperm Nelumbo (Nelumbonaceae) are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae), ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America.

  6. Late cretaceous aquatic plant world in Patagonia, Argentina.

    Directory of Open Access Journals (Sweden)

    N Rubén Cúneo

    Full Text Available In this contribution, we describe latest Cretaceous aquatic plant communities from the La Colonia Formation, Patagonia, Argentina, based on their taxonomic components and paleoecological attributes. The La Colonia Formation is a geological unit deposited during a Maastrichtian-Danian transgressive episode of the South Atlantic Ocean. This event resulted in the deposition of a series of fine-grained sediments associated with lagoon systems occurring along irregular coastal plains in northern Patagonia. These deposits preserved a diverse biota, including aquatic and terrestrial plants and animals. The aquatic macrophytes can be broadly divided into two groups: free-floating and rooted, the latter with emergent or floating leaves. Free-floating macrophytes include ferns in Salviniaceae (Azolla and Paleoazolla and a monocot (Araceae. Floating microphytes include green algae (Botryoccocus, Pediastrum and Zygnemataceae. Among the rooted components, marsileaceous water ferns (including Regnellidium and an extinct form and the eudicot angiosperm Nelumbo (Nelumbonaceae are the dominant groups. Terrestrial plants occurring in the vegetation surrounding the lagoons include monocots (palms and Typhaceae, ferns with affinities to Dicksoniaceae, conifers, and dicots. A reconstruction of the aquatic plant paleocommuniy is provided based on the distribution of the fossils along a freshwater horizon within the La Colonia Formation. This contribution constitutes the first reconstruction of a Cretaceous aquatic habitat for southern South America.

  7. Quantifying mass balance processes on the Southern Patagonia Icefield

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    M. Schaefer

    2014-06-01

    Full Text Available We present surface mass balance simulations of the Southern Patagonia Icefield driven by downscaled reanalysis data. The simulations were validated and interpreted using geodetic mass balances, measured point balances and a complete velocity field of the Icefield from spring 2004. The high measured accumulation of snow as well as the high measured ablation is reproduced by the model. The overall modeled surface mass balance was positive and increasing during 1975–2011. Subtracting the surface mass balance from geodetic balances, calving fluxes were inferred. Mass losses of the SPI due to calving were strongly increasing from 1975–2000 to 2000–2011 and higher than losses due to surface melt. Calving fluxes were inferred for the individual glacier catchments and compared to fluxes estimated from velocity data. Measurements of ice thickness and flow velocities at the glaciers' front and spatially distributed accumulation measurements can help to reduce the uncertainties of the different terms in the mass balance of the Southern Patagonia Icefield.

  8. Composición corporal de escolares pertenecientes a diferentes contextos socioeconómicos de Puerto Madryn, Chubut, Argentina

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    Dahinten, Silvia Lucrecia

    2007-01-01

    Full Text Available El desigual desarrollo del tejido muscular y de la distribución de tejido adiposo que tiene lugar durante el crecimiento humano presenta dimorfismo sexual (DS, en condiciones de vida saludables. Esta variación ha sido traducida en algoritmos utilizando la circunferencia y pliegues subcutáneos del brazo y se han elaborado ecuaciones para calcular áreas. El objetivo fue evaluar el DS observado en el crecimiento corporal de escolares de 6 a 14 años de hogares con diferente NBI -(NBI alto y (NBI bajo-. Se estudió transversalmente una muestra de 500 mujeres y 570 varones de la ciudad de Puerto Madryn, Chubut. Se relevaron: perímetro braquial y pliegues subcutáneos tricipital y subescapular y se calcularon las áreas adiposa (AAB y muscular (AMB. Se utilizaron pruebas de Wilcoxon, p= 0.05. El AAB de las mujeres fue a casi todas las edades superior a la de los varones (NBI bajo p=0.09; NBI alto p=0.02. A edades tempranas, el AMB mostró que los varones presentaron cifras similares a las mujeres. A partir de los 12 años, sin embargo, los varones comenzaron a incrementar la masa muscular. En las niñas este aumento se hizo mucho más lento (NBI alto p=0.01; NBI bajo p=0.03. La ausencia de DS en el NBI bajo, para los caracteres considerados, se relaciona con el aumento de tejido adiposo en los varones de este sector que muestra la adopción dentro de la comunidad, de dietas de alto contenido en grasas y carbohidratos acompañadas de altas tasas de obesidad.

  9. Los dueños del rebaño. Origen étnico y capacidad ovina en Chubut

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    Fernando Coronato

    2015-04-01

    Full Text Available Continuando la línea de investigación inaugurada por Elsa Barbería en “Los dueños de la tierra” en Santa Cruz, avanzamos sobre la distribución de las diferentes comunidades étnicas y su parte en el poblamiento patagónico a partir del análisis cartográfico diacrónico. Para el último período del proceso utilizamos la base de datos del catastro del Chubut (2006 para evaluar « la capacidad ganadera» (entendida como la acumulación de hectáreas y ovinos de cada comunidad étnica. Estas fueron asociadas a los grupos patronímicos identificados previamente, a saber: alemán, bóer, británico (inglés y escocés, español, francés, galés, italiano, mapuche, polaco, tehuelche y vasco. Las Sociedades Anónimas se consideraron como un grupo aparte. Del tratamiento estadístico de los datos se obtuvo la superficie media de las (más de 2000 propiedades, la talla media del rebaño y la cosecha de lana de cada grupo, detectándose diferencias significativas entre algunos de ellos. Las Sociedades Anónimas se despegan solitarias hacia los latifundios, mientras que en el extremo opuesto se ubican los grupos aborígenes, arrinconados en los minifundios y la subsistencia. Estos datos relativamente actuales muestran la continuidad de los procesos identificados en el análisis catastral de etapas previas del poblamiento que se remontan a más de un siglo.

  10. Caracterización geológica del skarn "El Abuelo" Alto Río Senguerr, Chubut

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    M.E. Lanfranchini

    2004-12-01

    Full Text Available El skarn "El Abuelo" está situado en el extremo sudoccidental de la Provincia del Chubut, República Argentina. Se desarrolla en un ambiente tectónico de arco magmático, en corteza continental. Está emplazado en sedimentitas silicoclásticas con intercalaciones carbonáticas y se vincula a cuerpos intrusivos riodacíticos, conjunto atribuido al Cretácico inferior. En esta manifestación se reconocieron anomalías en elementos metalíferos (Fe, Cu, Pb, Zn, Ag que le confieren interés como guía para la exploración de recursos minerales en esta región. La presente contribución tiene por finalidad tipificar al skarn a través de una caracterización geológica y mineralógica. La asociación paragenética de minerales reconocidos permitió identificar dos episodios: uno metasomático y otro hidrotermal, ambos desarrollados en las sedimentitas (exoskarn. El primero fue originado por fluidos de derivación magmática, que provocaron la formación de minerales calcosilicáticos. Posteriormente la incorporación de agua en el sistema facilitó el desarrollo de minerales hidratados, retrogradando parcialmente al skarn, proceso que fue seguido por la depositación de hematita, magnetita y sulfuros, acompañados de sílice. La asociación de minerales calcosilicáticos, junto a la variación en la composición química de piroxenos y granates y la mineralización identificada, permiten tipificar al skarn "El Abuelo" como cálcico, con hierro como metal dominante.

  11. Fe-Ni Micrometorites from Upper Jurassic Cañadon Asfalto Fm., Patagonia, Argentina

    Science.gov (United States)

    Matteini, M.; Hauser, N.; Cabaleri, N.; Silva Nieto, D.; Cuadros, F. A.; Reyes, S.

    2014-09-01

    Microspherules from an upper Jurassic sediments from Patagonia, show mineralogical, geochemical and textural features very similar to those reported for I-type micrometeorites whereas some spherules are interpreted as typical G-type micrometeorites.

  12. A Combined Observational and Modeling Approach to Study Modern Dust Transport from the Patagonia Desert to East Antarctica

    Science.gov (United States)

    Gasso, S.; Stein, A.; Marino, F.; Castellano, E.; Udisti, R.; Ceratto, J.

    2010-01-01

    The understanding of present atmospheric transport processes from Southern Hemisphere (SH) landmasses to Antarctica can improve the interpretation of stratigraphic data in Antarctic ice cores. In addition, long range transport can deliver key nutrients normally not available to marine ecosystems in the Southern Ocean and may trigger or enhance primary productivity. However, there is a dearth of observational based studies of dust transport in the SH. This work aims to improve current understanding of dust transport in the SH by showing a characterization of two dust events originating in the Patagonia desert (south end of South America). The approach is based on a combined and complementary use of satellite retrievals (detectors MISR, MODIS, GLAS ,POLDER, OMI,), transport model simulation (HYSPLIT) and surface observations near the sources and aerosol measurements in Antarctica (Neumayer and Concordia sites). Satellite imagery and visibility observations confirm dust emission in a stretch of dry lakes along the coast of the Tierra del Fuego (TdF) island (approx.54deg S) and from the shores of the Colihue Huapi lake in Central Patagonia (approx.46deg S) in February 2005. Model simulations initialized by these observations reproduce the timing of an observed increase in dust concentration at the Concordia Station and some of the observed increases in atmospheric aerosol absorption (here used as a dust proxy) in the Neumayer station. The TdF sources were the largest contributors of dust at both sites. The transit times from TdF to the Neumayer and Concordia sites are 6-7 and 9-10 days respectively. Lidar observations and model outputs coincide in placing most of the dust cloud in the boundary layer and suggest significant de- position over the ocean immediately downwind. Boundary layer dust was detected as far as 1800 km from the source and approx.800 km north of the South Georgia Island over the central sub-Antarctic Atlantic Ocean. Although the analysis suggests the

  13. Eriocóccidos (Hemiptera: Coccoidea encontrados en la Patagonia Argentina Eriococcidae (Hemiptera: Coccoidea found in Patagonia Argentina

    Directory of Open Access Journals (Sweden)

    Patricia González

    2004-07-01

    Full Text Available Se listan cuatro géneros y nueve especies de eriocóccidos presentes en la Patagonia argentina, sobre distintos huéspedes. Chilecoccus browni Miller & González, Chilecoccus spinossus Miller & González, Eriococcus novarinoensis Hoy, Eriococcus rhadinothrix Miller & González, Icelococcus nothofagi Miller & González, sobre Nothofagus dombeyi (Fagaceae. Eriococcus chilensis Miller & González, Eriococcus eurythrix Miller & González, Icelococcus charlini Miller & González, sobre Nothofagus antarctica. Eriococcus eurythrix Miller & González sobre Nothofagus alpina. Icelococcus charlini Miller & González sobre Nothofagus obliqua. Stibococcus cerinus Miller & González sobre Myrceugenia exsucca (Myrtaceae.We list four genera and nine species of eriococcid present in the Patagonia Argentina, on different hosts. Chilecoccus browni Miller & González, Chilecoccus spinossus Miller & González, Eriococcus novarinoensis Hoy, Eriococcus rhadinothrix Miller & González, Icelococcus nothofagi Miller & González, on Nothofagus dombeyi (Fagaceae. Eriococcus chilensis Miller & González, Eriococcus eurythrix Miller & González, Icelococcus charlini Miller & González, on Nothofagus antarctica. Eriococcus eurythrix Miller & González on Nothofagus alpina. Icelococcus charlini Miller & González on Nothofagus obliqua. Stibococcus cerinus Miller & González on Myrceugenia exsucca (Myrtaceae.

  14. PATAGONIA: DEL PRESENTE ETNOGRÁFICO AL PASADO ARQUEOLÓGICO (Patagonia: from the ethnographic present to the archaeological past

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    Arturo Sáez

    2011-03-01

    Full Text Available En este trabajo se analizan los principales argumentos utilizados desde diferentes perspectivas paleo-biológicas, paleo-lingüísticas, arqueológicas y antropológicas para explicar la diversidad y la conformación étnica de las poblaciones indígenas en Patagonia, tanto en el presente como en el pasado. Entendemos que una revisión conjunta y crítica de los supuestos disciplinares, sobre los cuales se continúa trabajando, permitirá observar e identificar los patrones que emergen del registro histórico, concernientes a la expresión de la variabilidad social patagónica. De igual modo, se propone una reflexión sobre las posibles proyecciones que plantea esta crítica hacia la exploración y la formulación de nuevas preguntas sobre el registro arqueológico. ENGLISH: This paper analyzes some of the main arguments from paleobiology, paleolinguistics, archaeology and anthropology to explain diversity and ethnic organization in the indigenous communities of Patagonia, both in the present and past. We believe that a critical review of the main assumptions from all these disciplines will allow us to observe and identify patterns emerging from the historical record of the expression of Patagonian social variability. Likewise, we suggest a new way of exploring the archaeological record rooted in critical theory.

  15. Ploidy levels and reproductive behaviour in invasive Hieracium pilosella in Patagonia

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    František Krahulec

    2011-11-01

    Full Text Available Within a population of invasive Hieracium pilosella in Chilean Patagonia we found two ploidy levels, pentaploid and hexaploid. Each ploidy level was represented by one clone. Their reproductive system was apomictic (and thus replicating the maternal genome, with a low degree of residual sexuality. It is necessary to prevent the evolution of new biotypes via hybridisation with different clones of H. pilosella or other Hieracium species introduced into Patagonia.

  16. Patagonian and Antarctic dust as recorded in the sediments of Laguna Potrok Aike (Patagonia, Argentina)

    Science.gov (United States)

    Haberzettl, Torsten; Stopp, Annemarie; Lisé-Pronovost, Agathe; Gebhardt, Catalina; Ohlendorf, Christian; Zolitschka, Bernd; von Eynatten, Hilmar; Kleinhanns, Ilka; Pasado Science Team

    2010-05-01

    Although an increasing number of terrestrial paleoclimatic records from southern South America has been published during the last decade, these archives mostly cover the Lateglacial and/or the Holocene. Only little is known about the Patagonian climate before the Last Glacial Maximum. Here, we present a continuous, high-resolution magnetic susceptibility record for the past 48 ka from the maar lake Laguna Potrok Aike (51°58' S, 70°23' W, southern Patagonia, Argentina). Magnetic susceptibility serves as an excellent parameter for the parallelization of sediment cores all over Laguna Potrok Aike including sediment cores taken within the ICDP (International Continental Scientific Drilling Program) project PASADO (Potrok Aike maar lake Sediment Archive Drilling prOject). Additionally, magnetic susceptibility is assumed to be a proxy for dust deposition in this lake. Distinct similarities were found between the independently dated magnetic susceptibility record from Laguna Potrok Aike and the non-sea-salt calcium (nss-Ca) flux from the EPICA Dome C ice core record (75°06'S, 123°24'E) the latter being a proxy for mineral dust deposition in Antarctica [1]. Comparison of the two records and variations in grain size of the Laguna Potrok Aike sediment records indicate a relatively high aeolian activity in southern South America during the glacial period. During the Holocene climatic conditions driving sediment deposition seem to have been more variable and less dominated by wind compared to glacial times. Although the source of the dust found in Antarctic ice cores often has been attributed to Patagonia [2], we present the first evidence for contemporaneity of aeolian deposition in both the target area (Antarctica) and the major source area (Patagonia). Considering the similarities of the two records, magnetic susceptibility might yield the potential for chronological information: transfer of the ice core age model to a lacustrine sediment record. This would be important

  17. Iridium, platinum and rhodium baseline concentration in lichens from Tierra del Fuego (South Patagonia, Argentina).

    Science.gov (United States)

    Pino, Anna; Alimonti, Alessandro; Conti, Marcelo Enrique; Bocca, Beatrice

    2010-10-06

    Lichen samples of Usnea barbata were used as possible biomonitors of the atmospheric background level of iridium (Ir), platinum (Pt) and rhodium (Rh) in the remote region of Tierra del Fuego (South Patagonia, Argentina). Lichens were collected in 2006 at 53 sites covering 7 different areas of the region (24 transplanted lichens of the northern region and 29 native lichen samples of the central-southern region). A microwave acidic digestion procedure was used to mineralize the samples and a sector field inductively coupled plasma mass spectrometry method was developed to quantify the elements. The study of the influence of interferences on analyte signals and a quality control procedure were carried out. The analytical protocol was further applied to evaluate Ir, Pt and Rh bioaccumulation in lichens. The detection limits obtained were 0.010 ng g⁻¹, 0.013 ng g⁻¹ and 0.030 ng g⁻¹ for Ir, Pt and Rh, respectively. Recoveries at different fortification levels were between 96.3% and 106% and precision was 3.3% on average. The metals concentration (as dry weight) spanned the following ranges: Ir, Fuego. Values detected are more likely influenced by the long-range atmospheric transport of these pollutants and, in comparison with densely populated areas in the world, they can represent the baseline for low impacted areas.

  18. A Middle Jurassic heterodontosaurid dinosaur from Patagonia and the evolution of heterodontosaurids

    Science.gov (United States)

    Pol, Diego; Rauhut, Oliver W. M.; Becerra, Marcos

    2011-05-01

    Heterodontosauridae is a morphologically divergent group of dinosaurs that has recently been interpreted as one of the most basal clades of Ornithischia. Heterodontosaurid remains were previously known from the Early Jurassic of southern Africa, but recent discoveries and studies have significantly increased the geographical and temporal range for this clade. Here, we report a new ornithischian dinosaur from the Middle Jurassic Cañadón Asfalto Formation in central Patagonia, Argentina. This new taxon, Manidens condorensis gen. et sp. nov., includes well-preserved craniomandibular and postcranial remains and represents the only diagnostic ornithischian specimen yet discovered in the Jurassic of South America so far. Derived features of its anatomy indicate that Manidens belongs to Heterodontosauridae, as the sister taxon of Heterodontosaurus and other South African heterodontosaurids. The presence of posterior dentary teeth with high crowns but lacking extensive wear facets in Manidens suggests that this form represents an intermediate stage in the development of the remarkable adaptations to herbivory described for Heterodontosaurus. The dentition of Manidens condorensis also has autapomorphies, such as asymmetrically arranged denticles in posterior teeth and a mesially projected denticle in the posteriormost teeth. At an estimated total length of 60-75 cm, Manidens furthermore confirms the small size of basal heterodontosaurids.

  19. A Middle Jurassic abelisaurid from Patagonia and the early diversification of theropod dinosaurs.

    Science.gov (United States)

    Pol, Diego; Rauhut, Oliver W M

    2012-08-22

    Abelisaurids are a clade of large, bizarre predatory dinosaurs, most notable for their high, short skulls and extremely reduced forelimbs. They were common in Gondwana during the Cretaceous, but exceedingly rare in the Northern Hemisphere. The oldest definitive abelisaurids so far come from the late Early Cretaceous of South America and Africa, and the early evolutionary history of the clade is still poorly known. Here, we report a new abelisaurid from the Middle Jurassic of Patagonia, Eoabelisaurus mefi gen. et sp. nov., which predates the so far oldest known secure member of this lineage by more than 40 Myr. The almost complete skeleton reveals the earliest evolutionary stages of the distinctive features of abelisaurids, such as the modification of the forelimb, which started with a reduction of the distal elements. The find underlines the explosive radiation of theropod dinosaurs in the Middle Jurassic and indicates an unexpected diversity of ceratosaurs at that time. The apparent endemism of abelisauroids to southern Gondwana during Pangean times might be due to the presence of a large, central Gondwanan desert. This indicates that, apart from continent-scale geography, aspects such as regional geography and climate are important to reconstruct the biogeographical history of Mesozoic vertebrates.

  20. Study of UV cloud modification factors in Southern Patagonia

    Science.gov (United States)

    Wolfram, Elian A.; Orte, Facundo; Salvador, Jacobo; Quiroga, Jonathan; D'Elia, Raúl; Antón, Manuel; Alados-Arboledas, Lucas; Quel, Eduardo

    2017-02-01

    Anthropogenic perturbation of the ozone layer has induced change in the amount of UV radiation that reaches the Earth's surface, mainly through the Antarctic ozone hole, making the ozone and ultraviolet (UV) radiation two important issues in the study of Earth atmosphere in the scientific community. Also the clouds have been identified as the main modulator of UV amount in short time scales and produce the main source of uncertainty in the projection of surface UV level as consequence of projected ozone recovery. While clouds can decrease direct radiation, they can produce an increase in the diffuse component, and as consequence the surface UV radiation may be higher than an equivalent clear sky scenario for several minutes. In particular this situation can be important when low ozone column and partially cloud cover skies happen simultaneously. These situations happen frequently in southern Patagonia, where the CEILAP Lidar Division has established the Atmospheric Observatory of Southern Patagonia, an atmospheric remote sensing site near the city of Río Gallegos (51°55'S, 69°14'W). In this paper, the impact of clouds over the UV radiation is investigated by the use of ground based measurements from the passive remote sensing instruments operating at this site, mainly of broad and moderate narrow band filter radiometers. We analyzed the UV Index obtained from a multiband filter radiometer GUV-541 (UVI) [Biospherical Inc.] installed in the Observatorio Atmosférico de la Patagonia Austral, Río Gallegos, since 2005. Cloud modification factors (CMF, ratio between the measured UV radiation in a cloudy sky and the simulated radiation under cloud-free conditions) are evaluated for the study site. The database used in this work covers the period 2005-2012 for spring and summer seasons, when the ozone hole can affect these subpolar regions. CMF higher than 1 are found during spring and summer time, when lower total ozone columns, higher solar elevations and high cloud

  1. Evolución geomorfológica y cronología relativa de los niveles aterrazados del área adyacente a la desembocadura del río Chubut al Atlántico (Provincia del Chubut

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    Emilio F González Díaz

    2011-12-01

    Full Text Available Se describe un antiguo abanico aluvial y su posterior evolución. Las acumulaciones del antiguo abanico aluvial han sido interpretadas como la continuidad septentrional de los rodados patagónicos de la meseta Montemayor, una propuesta que es rebatida. La base metodológica del reconocimiento del antiguo abanico aluvial y su distinción genética y temporal, la constituyó el análisis geomórfico y la evaluación altimétrica. Su asignación temporal es un problema aún no resuelto. La metodología condujo a diferenciar tres sistemas geomórficos o niveles, relacionados con sucesivos episodios de agradación y erosión, los que ocupan posiciones cada vez más inferiores, coincidiendo con el complejo paleodrenaje del antiguo abanico aluvial. Sus desarrollos sucesivos son vinculados con protoríos Chubut 1, 2, 3 propuestos y el correspondiente a un paleovalle Simpson. Pese a las limitaciones apuntadas, se propone que el modelo evolutivo del antiguo abanico aluvial responde a una estructura de corte y relleno, que avalaría una composición poliformacional del antiguo abanico aluvial y además la migración progresiva del paleodrenaje hacia el sur. Un análisis geomorfológico y altimétrico diferenció un nivel superior integrado por restos de tres planicies (Pa, Pm y Pb, un nivel medio con dos terrazas (T1 y T2 y un complejo nivel inferior de cinco terrazas (T3, T4, T5 T6 y T7. Evidencias relícticas de los paleodrenajes propuestos son los paleovalles Estancia Paz y Don Morgan-Saraza del nivel superior. La edad del antiguo abanico aluvial basada en la evolución geomórfica del área de estudio, es tentativamente asignada a un incierto lapso del Pleistoceno superior entre el interglacial Sangamon y fines de la última glaciación.

  2. Phytoseiid mites (Acari: Phytoseiidae) from Patagonia and Tierra del Fuego.

    Science.gov (United States)

    Ferragut, Francisco; Navia, Denise

    2015-07-28

    Predatory phytoseiid mites have been intensively studied and surveyed in the last decades because of their economic importance as biocontrol agents of agricultural pests. However, many regions of the world remain unexplored and the diversity of the family worldwide is still fragmentary. Up to date no phytoseiid species have been collected in the southernmost part of the Earth down to latitude 45º S. In this study Phytoseiidae were sampled from native vegetation in southern Argentina and Chile in the regions of Patagonia and Tierra del Fuego Island. Thirteen species were collected, five of which were previously described and eight, Chileseius australis n. sp., Neoseiulus mapuche n. sp., Typhlodromips valdivianus n. sp., T. fissuratus n. sp., Amblyseius grandiporus n. sp., A. caliginosus n. sp., Typhlodromus (Anthoseius) anomalos n. sp. and Metaseiulus parabrevicollis n. sp. are proposed as new to science and are described and diagnosed.

  3. Quantifying mass balance processes on the Southern Patagonia Icefield

    DEFF Research Database (Denmark)

    Schaefer, M.; Machguth, Horst; Falvey, M.;

    2015-01-01

    measured accumulation of snow of up to 15.4m w.e. yr(-1) (meters water equivalent per year) as well as the high measured ablation of up to 11m w.e. yr(-1) is reproduced by the model. The overall modeled surface mass balance was positive and increasing during 1975-2011. Subtracting the surface mass balance......We present surface mass balance simulations of the Southern Patagonia Icefield (SPI) driven by downscaled reanalysis data. The simulations were evaluated and interpreted using geodetic mass balances, measured point balances and a complete velocity field of the icefield for spring 2004. The high...... from geodetic balances, calving fluxes were inferred. Mass losses of the SPI due to calving were strongly increasing from 1975-2000 to 2000-2011 and higher than losses due to surface melt. Calving fluxes were inferred for the individual glacier catchments and compared to fluxes estimated from velocity...

  4. Vajilla para la gastronomía de la Patagonia

    OpenAIRE

    Rodandelli, Julieta

    2012-01-01

    La Patagonia es una de las reglones más ricas del país, con atractivos turísticos que la hacen reconocida lnternacionalmente. La comida forma parte de su cultura, refleja su identidad. Hoy en día, la gastronomía expandió su mercado y se especializa en comidas típicas de diferentes etnias y regiones. Por esta razón, al proponer como proyecto el desarrollo de una linea de vajilla, la primera pregunta que surgió fue: ¿existe una asociación entre la comida típica de la región y los utensilios en ...

  5. Splendid and Seldom Isolated: The Paleobiogeography of Patagonia

    Science.gov (United States)

    Wilf, Peter; Cúneo, N. Rubén; Escapa, Ignacio H.; Pol, Diego; Woodburne, Michael O.

    2013-05-01

    The idea that South America was an island continent over most of the Cenozoic, during which its unusual mammalian faunas evolved in isolation, is outstandingly influential in biogeography. Although large numbers of recent fossil discoveries and related advances require that the original isolation concept be significantly modified, it is still repeated in much current literature. The persistence of the idea inspired us to present here an integrated paleobiogeographic account of mammals, reptiles, and plants from the Jurassic to the Paleogene of Patagonia, which has by far the richest fossil record on the continent. All three groups show distribution patterns that are broadly consistent with South America's long separation history, first from Laurasia by the Late Jurassic, then from Africa and India-Madagascar during the late Early Cretaceous, and finally from Antarctica and Australia during the early-middle Eocene, after which “isolation” finally commenced. We highlight areas of promising future research and provide an updated view of South American isolation.

  6. Inventario preliminar y nuevos registros de Psychodidae no Phlebotominae (Diptera, Nematocera para Argentina, con especial referencia a la Patagonia

    Directory of Open Access Journals (Sweden)

    Guillermo H. OMAD

    2012-01-01

    y Nemoneura dealbata Tonnoir. Los sitios de muestreo para este trabajo se realizaron en diferentes zonas de las provincias de Chubut (Parque Nacional Los Alerces, Río Negro y Neuquén (Parque Nacional Nahuel Huapi, Buenos Aires y Misiones.

  7. Cenozoic back-arc magmatism of the southern extra-Andean Patagonia (44° 30' - 52° S: A review of geochemical data and geodynamic interpretations Magmatismo de retroarco cenozoico de la Patagonia extra-andina austral (44° 30' - 52° S: Una revisión de los datos geoquímicos e interpretaciones geodinámicas

    Directory of Open Access Journals (Sweden)

    M. D'Orazio

    2004-12-01

    Full Text Available Huge amounts of basaltic s.l. lavas were persistently erupted along the eastern side of the Andean Cordillera, throughout Cenozoic time, forming extensive plateaus, hundreds of monogenetic scoria cones and other volcanic structures in a continental back-arc setting. The igneous products exposed in the southern sector of the extra-Andean Patagonia (44° 30' - 52° S are dominantly mafic with minor slightly evolved compositions and rare highly differentiated products. The many published chemical analyses of these rocks, indicate that the mafic lavas range from strongly silica - undersaturated basanites to oversaturated basaltic andesites, and that most of the lavas have a typical within-plate geochemical signature. However, a number of lavas, generally erupted in the western-central sectors of Patagonia, are characterized by different distributions of the incompatible elements with high LILE/HFSE and LREE/HFSE ratios. The REE distribution modelling suggests a low degree of melting of a deep (> 70 km garnet-bearing source for the alkaline magmas, and a higher degree of melting of the same source, or an even higher degree of melting of an enriched source, for the subalkaline magmas. The available Sr-Nd-Pb isotope compositions clearly attest to a major geographic variation: the southernmost lavas have lower 87Sr/86Sr and higher 143Nd/144Nd and 206Pb/204Pb ratios with respect to those erupted to the north. On the whole, the Sr-Nd-Pb isotope compositions of the southern Patagonia lavas fall within the typical range of within-plate continental magmas; in addition the Pb isotope ratios fall in the range of the Southern Hemisphere Dupal Pb isotope anomaly. The geochemical variations of the southern Patagonia lavas are discussed in terms of different geochemical components: depleted and enriched sub-slab asthenosphere, enriched continental lithospheric mantle, continental crust and subducted materials. The geodynamic significance is interpreted with in the

  8. Jurassic tetrapods and flora of Cañadón Asfalto Formation in Cerro Cóndor area, Chubut Province Flora y tetrápodos del Jurásico de la Formación Cañadón Asfalto en el área de Cerro Cóndor, provincia de Chubut

    OpenAIRE

    2008-01-01

    The plant and tetrapod fossil record of the Cañadón Asfalto Formation (Middle to Late Jurassic) found in Cerro Cóndor area (Chubut Province) is summarized here. The flora is dominated by conifers (Araucariaceae, Cupressaceae sensu lato) but also includes ferns and equisetaleans. The tetrapod fauna is composed of dinosaur taxa described in the 70's as well as other remains recently described and other vertebrate groups such as amphibians, turtles, and mammals. The amphibian remains have been i...

  9. Hantavirus reservoir Oligoryzomys longicaudatus spatial distribution sensitivity to climate change scenarios in Argentine Patagonia

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    González Paula LM

    2009-07-01

    Full Text Available Abstract Background Oligoryzomys longicaudatus (colilargo is the rodent responsible for hantavirus pulmonary syndrome (HPS in Argentine Patagonia. In past decades (1967–1998, trends of precipitation reduction and surface air temperature increase have been observed in western Patagonia. We explore how the potential distribution of the hantavirus reservoir would change under different climate change scenarios based on the observed trends. Methods Four scenarios of potential climate change were constructed using temperature and precipitation changes observed in Argentine Patagonia between 1967 and 1998: Scenario 1 assumed no change in precipitation but a temperature trend as observed; scenario 2 assumed no changes in temperature but a precipitation trend as observed; Scenario 3 included changes in both temperature and precipitation trends as observed; Scenario 4 assumed changes in both temperature and precipitation trends as observed but doubled. We used a validated spatial distribution model of O. longicaudatus as a function of temperature and precipitation. From the model probability of the rodent presence was calculated for each scenario. Results If changes in precipitation follow previous trends, the probability of the colilargo presence would fall in the HPS transmission zone of northern Patagonia. If temperature and precipitation trends remain at current levels for 60 years or double in the future 30 years, the probability of the rodent presence and the associated total area of potential distribution would diminish throughout Patagonia; the areas of potential distribution for colilargos would shift eastwards. These results suggest that future changes in Patagonia climate may lower transmission risk through a reduction in the potential distribution of the rodent reservoir. Conclusion According to our model the rates of temperature and precipitation changes observed between 1967 and 1998 may produce significant changes in the rodent

  10. Angelaíta en la paragénesis del distrito Los Manantiales, provincia del Chubut: Una nueva especie mineral

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    M.K. de Brodtkorb

    2004-12-01

    Full Text Available Angelaíta, Cu2AgPbBiS2 , una nueva especie mineral, fue localizada en la mina Ángela, mineralización de tipo IS del distrito Los Manantiales, Chubut, Argentina. La paragénesis incluye esfalerita, pirita, calcopirita, galena y en menor cantidad arsenopirita, betekhtinita, bornita, matildita, oro, plata, electrum, telurio, cervelleíta y hematita. La galena presenta numerosas inclusiones de angelaíta, aikinita, wittichenita y miharaíta. Esta paragénesis se presenta en vetas asociada a diferentes rocas volcánicas de la Formación Lonco Trapial de edad jurásica. La composición química de angelaíta fue obtenida con una microsonda electrónica. Se presenta en granos anhedrales de 10-100mm, es de color gris verdoso, moderadamente pleocroica y anisótropa.

  11. Introduction and Establishment of Pissodes castaneus (Coleoptera: Curculionidae) in the Andean Patagonia of Argentina.

    Science.gov (United States)

    Pereyra, V A; Gomez, C A; La Manna, L; Roux, G; Lanteri, A A; Vallejos, N C; Marvaldi, A E

    2016-02-01

    The pine weevils that occur in plantations of Pinus spp. in Andean Patagonia of Argentina belong to the species Pissodes castaneus (De Geer), a Eurasian endemic species, according to the identification based on molecular and morphological characters. Sequences of the mitochondrial Cytochrome oxidase subunit I and nuclear genes (28 S rDNA and ITS2) were obtained for individuals of 13 afforestations, covering the entire distribution area of the established populations in the Andean Patagonia of Argentina. Sequence comparison with representative species of the genus (European, North American, and Chinese species) shows that Patagonian specimens are conspecific to those of P. castaneus sequenced from Europe. Phylogenetic analyses indicate that all terminals from Patagonia form a monophyletic unit without evident subclades, eliminating the possibility of existence of more than one species of Pissodes Germar in this area, including cryptic ones. Moreover, the very low genetic divergence between the Patagonian populations suggests that it is plausible that P. castaneus was introduced into Patagonia from just one location. Mitochondrial DNA analysis shows that Patagonian terminals group together with a French haplotype and are clearly separated from other P. castaneus individuals represented in our sample, and reveal that established populations in Andean Patagonia originated via a limited introduction.

  12. New Constraints on Maar Geometry and Sedimentary Fill of Laguna Potrok Aike, Southern Patagonia

    Science.gov (United States)

    Gebhardt, C. A.; Niessen, F.; Anselmetti, F.; Ariztegui, D.; de Batist, M.; Haberzettl, T.; Ohlendorf, C.; Zolitschka, B.

    2007-12-01

    Laguna Potrok Aike is located in Southern Patagonia, Argentina, at 52°S and 70°W. The maar lake has a diameter of 3.5 km and is almost circular and bowl-shaped with a deep, flat plain (100 m water depth) in its central part. Steep flanks separate the lake shoulders at 15 to 35 m water depth from the central plain. The lake is situated in the Pali Aike Volcanic Field at the present boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. Its lake level is highly susceptible to changes in the Antarctic Circumpolar Current that controls the regional precipitation patterns. Its sedimentary infill possibly contains a long and continuous record of several glacial and interglacial cycles, which is unique in the southern South American realm. Two major stratigraphic units (I and II) were distinguished in the seismic sections. Unit I consists of the lacustrine infill and was further subdivided into Sub-units I-a and I-b on the lake shoulders and I-ab, I-c, and I-d in the central basin. Sub-units I-a and I-b on the lake shoulders are separated by a major unconformity and contain several paleoshoreline structures formed during a step-wise transgression after a lake level lowstand of approx. 35 m below the present lake level. In the central basin, Sub-units I-a and I-b are merged into Sub-unit I-ab, not being separated by any unconformity. Pelagic sedimentation dominates in the northern and central parts, whereas mass movement deposits were found in the southern, western and eastern parts close to the steep diatreme flanks. The boundary between I-ab and I-c is non-erosive with I-ab forming downlaps onto I-c from the eastern and western parts of the lake, pointing at a significantly lower lake level during its accumulation. Sub-unit I-d shows similar characteristics as I-ab. The bedrock (Unit II) that forms the steep diatreme flanks consists of the well-layered sandstones found in the lake surroundings.

  13. Root proliferation in native perennial grasses of arid Patagonia, Argentina

    Institute of Scientific and Technical Information of China (English)

    Yanina A. TORRES; Mara M. MUJICA; Sandra S. BAIONI; Jos ENTO; Mara N. FIORETTI; Guillermo TUCAT; Carlos A. BUSSO; Oscar A. MONTENEGRO; Leticia ITHURRART; Hugo D. GIORGETTI; Gustavo RODRGUEZ; Diego BENTIVEGNA; Roberto E. BREVEDAN; Osvaldo A. FERNNDEZ

    2014-01-01

    Pappophorum vaginatum is the most abundant C4 perennial grass desirable to livestock in rangelands of northeastern Patagonia, Argentina. We hypothesized that (1) defoliation reduce net primary productivity, and root length density and weight in the native species, and (2) root net primary productivity, and root length density and weight, are greater in P. vaginatum than in the other, less desirable, native species (i.e., Aristida spegazzinii, A. subulata and Sporobolus cryptandrus). Plants of all species were either exposed or not to a severe defoliation twice a year during two growing seasons. Root proliferation was measured using the cylinder method. Cylindrical, iron structures, wrapped up using nylon mesh, were buried diagonally from the periphery to the center on individual plants. These structures, initially filled with soil without any organic residue, were dug up from the soil on 25 April 2008, after two successive defoliations in mid-spring 2007. During the second growing season (2008-2009), cylinders were destructively harvested on 4 April 2009, after one or two defoliations in mid-and/or late-spring, respectively. Roots grown into the cylinders were obtained after washing the soil manually. Defoliation during two successive years did reduce the study variables only after plants of all species were defoliated twice, which supported the first hypothesis. The greater root net primary productivity, root length den-sity and weight in P. vaginatum than in the other native species, in support of the second hypothesis, could help to explain its greater abundance in rangelands of Argentina.

  14. Hydrogen energy demonstration plant in Patagonia: Description and safety issues

    Energy Technology Data Exchange (ETDEWEB)

    Aprea, Jose Luis [CNEA (Argentine Atomic Energy Commission), AAH, IRAM, Comahue University, CC 805, 8300 Neuquen (Argentina)

    2009-05-15

    Hydrogen safety issues and especially hydrogen hazard's address are key points to remove any safety-related barrier in the implementation process of hydrogen energy systems. Demonstrative systems based on hydrogen technologies represent a clear contribution to the task of showing the feasibility of the new technologies and their beneficial capabilities among the public. In this paper, the safety features of the first hydrogen energy demonstrative plant conceived in Latin America are analyzed. The facilities, located in the village of Pico Truncado, Patagonia, Argentina, serve to gain day-to-day experience in the production, storage, distribution, conversion and use of hydrogen in several applications. The plant uses electrolysis to generate pure hydrogen from renewable primary sources, taking advantage of the installed wind power capacity that is continually growing in the region. The installations were designed to accomplish with two primary objectives: total safety assurance and minimization of human errors. Some details of the plant, including a general layout, are presented here, in addition with design criteria, hydrogen hazards, structural precautions, gas monitoring system, existing regulations and safety requirements. (author)

  15. Chironomid (Chironomidae: Diptera checklist from Nahuel Huapi National Park, Patagonia, Argentina Lista de los quironómidos (Chironomidae: Diptera del Parque Nacional Nahuel Huapi, Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    Mariano Donato

    2008-06-01

    Full Text Available This paper presents the first inventory of modern and subfossil taxa of the Family Chironomidae (Insecta: Diptera from Nahuel Huapi National Park in Patagonia, Argentina. The catalogued fauna contains 104 species in 48 genera and 6 sub-families for modern fauna and 52 morphotypes in 36 genera and 4 subfamilies for sub-fossil fauna.Este trabajo presenta el primer catálogo de taxones modernos y subfósiles de la familia Chironomidae (Insecta: Diptera del Parque Nacional Nahuel Huapi en Patagonia, Argentina. La fauna catalogada contiene 104 especies en 48 géneros y 6 subfamilias para la fauna moderna y 52 morfotipos en 36 géneros y 4 subfamilias para la fauna subfósil.

  16. Polen y vegetación en la Patagonia extraandina argentina a 45º S

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    Burry, Lidia S.

    2005-12-01

    Full Text Available Modern pollen dispersal and deposition in relation to vegetation and environmental variables at 45° S was studied in Argentinian Patagonia east of the Andes to build a modern pollen model. This model will serve to identify modern pollen assemblages that are analog of past pollen assemblages. A west-to-east gradient of decreasing precipitation and increasing temperature determines four vegetation units: (1 grass steppe, (2 grass-bush steppe, (3 bush steppe and (4 bush-brush steppe. Pollen samples were analyzed by classification and ordination methods, and correlated to environmental variables. The steppes (a dominated by the functional type grass, (1 grass steppe, and (2 grass-bush steppe located in the more humid and cooler west end of the region were separated from the (b bush-dominated steppes (3 bush steppe and (4 bush-brush steppe occurring in the central and eastern parts of the region, where conditions are drier and warmer. Azonal communities were identified as halophytic bush steppes within different vegetation units along the west-east gradient. Environmental variables related to vegetation distribution are temperature and interannual precipitation variability associated with the precipitation gradient from the cordillera to the coast, and soil salinity in the case of azonal communities.Se investigó la relación de la dispersión-deposición del polen actual con la vegetación y con variables ambientales en la Patagonia extraandina argentina a 45° S con el fin de construir un modelo polínico actual. Este modelo servirá para identificar los conjuntos polínicos actuales que sean análogos de conjuntos polínicos fósiles. En la región hay un gradiente decreciente de precipitación y creciente de temperatura de oeste a este, que determina la existencia de diferentes unidades de vegetación: (1 estepa graminosa; (2 estepa graminosa-arbustiva; (3 estepa arbustiva y (4 estepa arbustiva-matorral. Los datos de polen de muestras de suelo

  17. PLANTAS AROMÁTICAS CON ÓRGANOS SUBTERRÁNEOS DE IMPORTANCIA CULTURAL EN LA PATAGONIA ARGENTINA: UNA APROXIMACIÓN A SUS USOS DESDE LA ETNOBOTÁNICA, LA PERCEPCIÓN SENSORIAL Y LA ANATOMÍA

    Directory of Open Access Journals (Sweden)

    Soledad Molares

    2012-01-01

    Full Text Available Se analiza la etnobotánica y anatomía de cinco especies aromáticas de uso medicinal y/o comestible altamente valoradas en la Patagonia argentina: Valeriana clarionifolia, V. carnosa (Valerianaceae, Azorella monantha, Osmorhiza chilensis y Eryngium paniculatum (Apiaceae. El principal énfasis ha sido la caracterización de las estructuras secretoras de sus órganos subterráneos y su posible vinculación con las percepciones sensoriales y usos dados por los pobladores. El trabajo etnobotánico se realizó en dos comunidades indígenas Mapuches de la Provincia de Neuquén y en otras dos de la Provincia de Chubut, con un total de 53 entrevistas. El trabajo anatómico consistió en la observación estructural y ultraestructural de las estructuras secretoras. Los informantes indicaron que E. paniculatum es principalmente usada para tratar trastornos digestivos y hepáticos, O. chilensis para problemas de la visión y A. monantha como urinaria y antitusiva; además los órganos subterráneos de estas tres especiesse consumen crudos y/o cocidos. Las especies de Valeriana son usadas principalmente como analgésicas, digestivas, antitusivas y en síndromes culturales. El sabor y el aroma son las principales propiedades sensoriales usadas para reconocer y usar las especies de Valeriana y O. chilensis. A. monantha y E. paniculatum son reconocidas por sus características morfológicas, aunque también se valoranpor su sabor y aroma. Las observaciones microscópicas revelan la presencia de cavidades secretoras esquizógenas en O. chilensis, E. paniculatum y A. monantha y abundante presencia de almidón. En las especies de Valeriana se observa la peridermiscon elevado contenido de aceites esenciales como gotas. Se concluye que estas cinco especies poseen atributos organolépticos originados en estructuras anatómicas especializadas, los que en parte explicarían sus empleos alimenticios y/o medicinales.

  18. Organic carbon in glacial fjords of Chilean Patagonia

    Science.gov (United States)

    Pantoja, Silvio; Gutiérrez, Marcelo; Tapia, Fabián; Abarzúa, Leslie; Daneri, Giovanni; Reid, Brian; Díez, Beatriz

    2016-04-01

    The Southern Ice Field in Chilean Patagonia is the largest (13,000 km2) temperate ice mass in the Southern hemisphere, yearly transporting ca. 40 km3 of freshwater to fjords. This volume of fresh and cold water likely affects adjacent marine ecosystems by changing circulation, productivity, food web dynamics, and the abundance and distribution of planktonic and benthic organisms. We hypothesize that freshwater-driven availability of inorganic nutrient and transport of organic and inorganic suspended matter, as well as microbes, become a controlling factor for productivity in the fjord associated with the Baker river and Jorge Montt glacier. Both appear to be sources of silicic acid, but not of nitrate and particulate organic carbon, especially during summer, when surface PAR and glacier thawing are maximal. In contrast to Baker River, the Jorge Montt glacier is also a source of dissolved organic carbon towards a proglacial fjord and the Baker Channel, indicating that a thorough chemical description of sources (tidewater glacier and glacial river) is needed. Nitrate in fiord waters reaches ca. 15 μM at 25 m depth with no evidence of mixing up during summer. Stable isotope composition of particulate organic nitrogen reaches values as low as 3 per mil in low-salinity waters near both glacier and river. Nitrogen fixation could be depleting δ15N in organic matter, as suggested by the detection at surface waters of nif H genes belonging to diazotrophs near the Montt glacier. As diazotrophs have also been detected in other cold marine waters (e.g. Baltic Sea, Arctic Ocean) as well as glaciers and polar terrestrial waters, there is certainly a potential for both marine and freshwater microbes to contribute and have a significant impact on the Patagonian N and C budgets. Assessing the impact of freshwater on C and N fluxes and the microbial community structure in Patagonian waters will allow understanding future scenarios of rapid glacier melting. This research was funded

  19. Estado actual del conocimiento del orden Odonata en la Patagonia Current knowledge of Patagonian Odonata

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    Javier Muzón

    2009-06-01

    Full Text Available El orden Odonata se encuentra representado en la Patagonia por 36 especies, reunidas en nueve familias y 18 géneros. El nivel de endemismo de esta taxocoenosis es alto, aproximadamente el 60% de las especies y casi el 40% de los géneros endémicos. La riqueza específica en la Patagonia decrece de Oeste a Este y de Norte a Sur, las áreas de mayor riqueza resultan ser las cordilleras de Nahuel Buta (Chile y de los Andes entre 38° y 41° S, y la meseta de Somuncurá (Argentina en la estepa. Se brinda una actualización del estado de conocimiento y un análisis de los principales patrones de distribución.The Odonata order is represented in Patagonia by 36 species belonging to nine families and 18 genera. The endemicity level is high being approximately 60% of the species and 40% of genera endemic. The specific richness in Patagonia decreases from West to East and from North to South, being Nahuel Buta (Chile and Andes mountains between 38° and 41° S on the forest area, and the Somuncurá plateau (Argentina on the steppe the richest areas. An update of its records and an analysis of the main distribution patterns are provided in this paper.

  20. Moraine-dammed lake failures in Patagonia and assessment of outburst susceptibility in the Baker Basin

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    P. Iribarren Anacona

    2014-07-01

    Full Text Available Glacier retreat since the Little Ice Age has resulted in the development or expansion of hundreds of glacial lakes in Patagonia. Some of these lakes have produced large (≥106 m3 Glacial Lake Outburst Floods (GLOFs damaging inhabited areas. GLOF hazard studies in Patagonia have been mainly based on the analysis of short-term series (≤50 years of flood data and until now no attempt has been made to identify the relative susceptibility of lakes to failure. Power schemes and associated infrastructure are planned for Patagonian basins that have historically been affected by GLOFs, and we now require a thorough understanding of the characteristics of dangerous lakes in order to assist with hazard assessment and planning. In this paper, the conditioning factors of 16 outbursts from moraine dammed lakes in Patagonia were analysed. These data were used to develop a classification scheme designed to assess outburst susceptibility, based on image classification techniques, flow routine algorithms and the Analytical Hierarchy Process. This scheme was applied to the Baker Basin, Chile, where at least 7 moraine-dammed lakes have failed in historic time. We identified 386 moraine-dammed lakes in the Baker Basin of which 28 were classified with high or very high outburst susceptibility. Commonly, lakes with high outburst susceptibility are in contact with glaciers and have moderate (>8° to steep (>15° dam outlet slopes, akin to failed lakes in Patagonia. The proposed classification scheme is suitable for first-order GLOF hazard assessments in this region. However, rapidly changing glaciers in Patagonia make detailed analysis and monitoring of hazardous lakes and glaciated areas upstream from inhabited areas or critical infrastructure necessary, in order to better prepare for hazards emerging from an evolving cryosphere.

  1. Moraine-dammed lake failures in Patagonia and assessment of outburst susceptibility in the Baker Basin

    Science.gov (United States)

    Iribarren Anacona, P.; Norton, K. P.; Mackintosh, A.

    2014-12-01

    Glacier retreat since the Little Ice Age has resulted in the development or expansion of hundreds of glacial lakes in Patagonia. Some of these lakes have produced large (≥ 106 m3) Glacial Lake Outburst Floods (GLOFs) damaging inhabited areas. GLOF hazard studies in Patagonia have been mainly based on the analysis of short-term series (≤ 50 years) of flood data and until now no attempt has been made to identify the relative susceptibility of lakes to failure. Power schemes and associated infrastructure are planned for Patagonian basins that have historically been affected by GLOFs, and we now require a thorough understanding of the characteristics of dangerous lakes in order to assist with hazard assessment and planning. In this paper, the conditioning factors of 16 outbursts from moraine-dammed lakes in Patagonia were analysed. These data were used to develop a classification scheme designed to assess outburst susceptibility, based on image classification techniques, flow routine algorithms and the Analytical Hierarchy Process. This scheme was applied to the Baker Basin, Chile, where at least seven moraine-dammed lakes have failed in historic time. We identified 386 moraine-dammed lakes in the Baker Basin of which 28 were classified with high or very high outburst susceptibility. Commonly, lakes with high outburst susceptibility are in contact with glaciers and have moderate (> 8°) to steep (> 15°) dam outlet slopes, akin to failed lakes in Patagonia. The proposed classification scheme is suitable for first-order GLOF hazard assessments in this region. However, rapidly changing glaciers in Patagonia make detailed analysis and monitoring of hazardous lakes and glaciated areas upstream from inhabited areas or critical infrastructure necessary, in order to better prepare for hazards emerging from an evolving cryosphere.

  2. Estado actual del conocimiento de la familia Ceratopogonidae en la Patagonia (Diptera: Nematocera Current knowledge of the family Ceratopogonidae in Patagonia (Diptera: Nematocera

    Directory of Open Access Journals (Sweden)

    Gustavo R. Spinelli

    2009-06-01

    Full Text Available Ceratopogonidae incluye pequeños dípteros nematoceros que crían en hábitats acuáticos o semiacuáticos. Hasta los '80, el conocimiento de su taxonomía en la Patagonia se hallaba limitado a la contribución de los comienzos de los '30 de Ingram y Macfie, sobre la base de material capturado en 1926-27, en el área del Parque Nacional Nahuel Huapi y zonas vecinas de Chile. En los últimos 25 años, se pusieron en marcha diferentes proyectos, resultando la descripción o registro de numerosos taxones para la región. Si se contabilizan los datos publicados, 102 especies habitan en la Patagonia, de las cuales 86 (84,31% son endémicas para la región. Este alto porcentaje es evidente en los bosques de Nothofagus, con 71 especies endémicas de este bioma, nueve lo son de la estepa y seis presentan registros en bosque y estepa. Datos aún no publicados concuerdan con este esquema. Diecinueve géneros están representados en la Patagonia, diez de ellos con amplia distribución, tres de distribución transantártica y seis son endémicos para el área. Para la misma, se hallan publicadas las revisiones de Forcipomyia, Atrichopogon, Borkenthelea, Macrurohelea y Paradasyhelea; se han finalizado y aún no publicado aquellas de Dasyhelea y Palpomyia, está muy avanzada la de Stilobezzia y se prevé comenzar con las de Austrohelea, Austrosphaeromias, Physohelea y Bezzia. Se calcula que estos datos no divulgados contienen al menos 55 especies todavía no descriptas. Con respecto a los aspectos biogeográficos se pueden destacar estudios que tienden a establecer relaciones entre las áreas reconocidas en esquemas biogeográficos propuestos para la región andina.Ceratopogonidae includes small nematoceran Diptera which breed in aquatic and semiaquatic habitats. Until the 80´s its taxonomic knowledge in Patagonia was limited to the early 30´s contribution of Ingram and Macfie, from material collected in 1926-27 in the area of the Nahuel Huapi National

  3. Biodiversidad de Heteroptera (Hemiptera acuáticas y semiacuáticas de la Patagonia argentina Biodiversity of aquatic and semiaquatic Heteroptera (Hemiptera from Argentinean Patagonia

    Directory of Open Access Journals (Sweden)

    María Cecilia Melo

    2009-06-01

    Full Text Available Las Heteroptera acuáticas y semiacuáticas (infraórdenes Nepomorpha, Gerromorpha y Leptopodomorpha no presentan una alta diversidad específica en Argentina, hasta el momento se han registrado 208 especies. Carlos Berg en 1881, publica el primer trabajo que hace referencia a heterópteros de la Patagonia, en el que lista los insectos recolectados durante la Campaña del Desierto. Desde principios de la década del '60, las Heteroptera acuáticas han sido estudiadas principalmente por A.O. Bachmann y colaboradores. Hasta el momento, se han registrado 36 especies pertenecientes a las familias Corixidae, Notonectidae, Belostomatidae, Gelastocoridae, Naucoridae y Nepidae (Nepomorpha; Hydrometridae, Veliidae y Mesoveliidae (Gerromorpha, y Saldidae (Leptopodomorpha. La mayoría de estas especies extienden su distribución geográfica hacia el norte de la Argentina, excepto Sigara (Tropocorixa egbertae Hungerford, S. (T. trimaculata (Le Guillou, S. (T. vuriloche Bachmann, S. (T. forciceps (Spinola, Trichocorixa milicorum Bachmann (Corixidae, Notonecta (Paranecta virescens Blanchard, N. (P. fazi Hungerford, N. (P. vereertbruggheni Hungerford (Notonectidae, Pseudosaldula bergi (Haglund y P. paralia (Torres, P. angusta (Drake & Carvalho, P. sola (Drake & Carvalho, P. doeringi (Drake & Carvalho y Saldula differata Drake & Carvalho (Saldidae, que son exclusivas de la Patagonia. El conocimiento de la diversidad de Heteroptera acuáticas y semiacuáticas en la Patagonia es bueno y, por los datos recogidos, su estado de conservación es aceptable ya que aproximadamente el 40% de la especies encontradas en áreas naturales protegidas son exclusivas de la región y representan cerca del 40 % del número de especies exclusivas de la Patagonia.The aquatic and semiaquatic Heteroptera (infraorders Nepomorpha, Gerromorpha and Leptopodomorpha show a low diversity in Argentina; up to now 208 species have been recorded. In 1881 Carlos Berg provided the first reference

  4. Patagonia, de margen exótico a periferia turística. Una mirada sobre un área natural protegida de frontera

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    Paula Gabriela Núñez

    2012-01-01

    Full Text Available During the first half of the twentieth century, National Parks in Argentina were located in peripheral border spaces. This configuration responded to previous territorial organization logics developed in the country. In order to analyze the impact and influence of these Natural Protected Areas, the Nahuel Huapi National Park (Andean Patagonia, Argentina case study was considered. It was concluded that, in the region of the Nahuel Huapi, the centralization in the national territorial administration was consolidated through the institutionalization of a Natural Protected Area. Moreover, this process allowed the identification of different approaches from which local planning development and tourism were thought over time, affecting the way Natural Protected Areas were conceived.

  5. Proyecto de Plaza-Embarcadero en Caleta Tortel, Región de Aysén, Patagonia de Chile / Embarcadero Plaza-Project in Tortel, Region of Aysen Patagonia, Chile.

    Directory of Open Access Journals (Sweden)

    Medel Santibáñez, Paulina Andrea

    2007-06-01

    Full Text Available El proyecto de Título de Arquitectura, 2007, que se presenta tiene como objetivo central dar respuesta a necesidades reales, preservando y cuidando del medio local, tanto natural como sociocultural, dentro de la dinámica actual de cambios y apertura. Se reconoce los atributos y potencialidades propios de Caleta Tortel para preservar su identidad cultural y patrimonial a través de la consideración de la relación con su entorno, específicamente, reconociendo el vínculo entre la localidad y el mar como medio elemental que le da origen y permite su desarrollo. La “Plaza-Embarcadero" en Caleta Tortel es un conjunto de carácter público, de escala comunal y con un programa comunitario integrador y abierto para la interacción diaria y directa de los habitantes y visitantes.This work leading to the professional degree in architecture is an answer to certain needs of Caleta Tortel in the Chilean Patagonia, adapting itself to the local environment –social and natural- and to the changes of globalization. The core idea of this project is to preserve the spatial and economic link between the town and the sea. The proposed wharf is a meeting point for the neighbours and tourists.

  6. Jurassic tetrapods and flora of Cañadón Asfalto Formation in Cerro Cóndor area, Chubut Province

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    Ignacio H. Escapa

    2008-12-01

    Full Text Available The plant and tetrapod fossil record of the Cañadón Asfalto Formation (Middle to Late Jurassic found in Cerro Cóndor area (Chubut Province is summarized here. The flora is dominated by conifers (Araucariaceae, Cupressaceae sensu lato but also includes ferns and equisetaleans. The tetrapod fauna is composed of dinosaur taxa described in the 70's as well as other remains recently described and other vertebrate groups such as amphibians, turtles, and mammals. The amphibian remains have been interpreted as representatives of a new species of Notobatrachus, considered one of the most basal members of the anuran lineage. Similarly, turtle remains have been recently recognized as a new species of basal turtle, bringing valuable information about the early evolution of this group. The dinosaur remains are largely dominated by saurischian taxa, represented by basal forms of Eusauropoda and Tetanurae. In addition, three different mammalian species have been identified and considered as early representatives of an endemic Gondwanan mammalian fauna. The fossil record of this formation represents the most completely known biota from the continental Middle to Late Jurassic of the Southern Hemisphere and one of the most complete of the entire world.

  7. Caracterización palinológica de las mieles de la llanura del río Senguerr (Chubut-Argentina

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    Alicia Forcone

    2000-01-01

    Full Text Available Forcone, A. & Tellería, M. C. 2000. Caracterización palinológica de las mieles de la llanuradel río Senguerr (Chubut-Argentina. Darwiniana 38(3-4: 267-271.Con el fin de conocer las plantas melíferas de la llanura del río Senguerr, se realizó el análisispalinológico de 19 muestras de miel. El estudio permitió identificar 57 tipos morfológicos y demostrarque las principales fuentes de néctar pertenecen a las familias Fabaceae, Rosaceae, Brassicaceae yAsteraceae. Del total de muestras analizadas 9 resultaron mixtas y 10 monoflorales, de estas últimas, 8fueron de Melilotus sp. y 2 de Rosaceae. Las mieles estudiadas pueden ser caracterizadas por unaasociación polínica de Trifolieae, Brassicaceae, Rosaceae, Acaena sp., Glycyrrhiza astragalina Gillies exHook. & Arn. and Cyperaceae. En la mayoría de las muestras el contenido polínico fue inferior a 2000granos/gramo

  8. Cuatro nuevas especies del género Liolaemus (Iguania: Liolaemidae, pertenecientes al grupo boulengeri, de la Patagonia, Argentina

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    Abdala, Cristian Simón

    2003-12-01

    Full Text Available Se describen cuatro nuevas especies del género Liolaemus, pertenecientes al grupo boulengeri, caracterizado por la presencia de un parche femoral de escamas agrandadas en la parte posterior del fémur. Una especie fue colectada en el sur de la provincia de Neuquén y las otras tres en el suroeste, centro y este de la provincia de Río Negro, en la Patagonia Argentina. Dentro del grupo las nuevas especies están relacionadas fenéticamente a Liolaemus boulengeri. Se estudiaron 98 caracteres morfológicos externos, referidos principalmente a caracteres de lepidosis, patrón de coloración y proporciones corporales, corrientemente estudiados en Liolaemus. Las diferencias más significativas entre estas especies y Liolaemus boulengeri se dan principalmente en el patrón de coloración y en algunos caracteres de escamación. Estas especies ocupan parte de las tres regiones patagónicas que se diferencian con base en la orografía y vegetación asociada. Las nuevas especies del centro y suroeste de la provincia de Río Negro, soportan grandes diferencias de temperatura diarias y estacionales. Las cuatro especies que se describen aquí se alimentan principalmente de insectos. Four new species of Liolaemus are described from the Patagonia region of southern Argentina. One species was collected in southern Neuquén Province and the other three are from Río Negro Province. Each of the new species has a patch of enlarged scales on the posterior surface of the thighs, indicating their relationship to members of the boulengeri group. Within this group, the four new species are morphologically most similar, and may be most closely related to, Liolaemus boulengeri. A total of 98 external morphological characters, principally squamation, color pattern, and body proportions, were recorded for these new members of the boulengeri group and compared with those for Liolaemus boulengeri. Significant differences between the new species and Liolaemus boulengeri were

  9. Use of timesat to estimate phenological parameters in Northwestern Patagonia

    Science.gov (United States)

    Oddi, Facundo; Minotti, Priscilla; Ghermandi, Luciana; Lasaponara, Rosa

    2015-04-01

    Under a global change context, ecosystems are receiving high pressure and the ecology science play a key role for monitoring and assessment of natural resources. To achieve an effective resources management to develop an ecosystem functioning knowledge based on spatio-temporal perspective is useful. Satellite imagery periodically capture the spectral response of the earth and remote sensing have been widely utilized as classification and change detection tool making possible evaluate the intra and inter-annual plant dynamics. Vegetation spectral indices (e.g., NDVI) are particularly suitable to study spatio-temporal processes related to plant phenology and remote sensing specific software, such as TIMESAT, has been developed to carry out time series analysis of spectral indexes. We used TIMESAT software applied to series of 25 years of NDVI bi-monthly composites (240 images covering the period 1982-2006) from the NOAA-AVHRR sensor (8 x 8 km) to assessment plant pheonology over 900000 ha of shrubby-grasslands in the Northwestern of Patagonia, Argentina. The study area corresponds to a Mediterranean environment and is part of a gradient defined by a sharp drop west-east in the precipitation regime (600 mm to 280 mm). We fitted the temporal series of NDVI data to double logistic functions by least-squares methods evaluating three seasonality parameters: a) start of growing season, b) growing season length, c) NDVI seasonal integral. According to fitted models by TIMESAT, start average of growing season was the second half of September (± 10 days) with beginnings latest in the east (dryer areas). The average growing season length was 180 days (± 15 days) without a clear spatial trend. The NDVI seasonal integral showed a clear trend of decrease in west-east direction following the precipitation gradient. The temporal and spatial information allows revealing important patterns of ecological interest, which can be of great importance to environmental monitoring. In this

  10. Forest Typification to Characterize the Structure and Composition of Old-growth Evergreen Forests on Chiloe Island, North Patagonia (Chile

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    Jan R. Bannister

    2013-11-01

    Full Text Available The Evergreen forest type develops along the Valdivian and North-Patagonian phytogeographical regions of the south-central part of Chile (38° S–46° S. These evergreen forests have been scarcely studied south of 43° S, where there is still a large area made up of old-growth forests. Silvicultural proposals for the Evergreen forest type have been based on northern Evergreen forests, so that the characterization of the structure and composition of southern Evergreen forests, e.g., their typification, would aid in the development of appropriate silvicultural proposals for these forests. Based on the tree composition of 46 sampled plots in old-growth forests in an area of >1000 ha in southern Chiloé Island (43° S, we used multivariate analyses to define forest groups and to compare these forests with other evergreen forests throughout the Archipelago of North-Patagonia. We determined that evergreen forests of southern Chiloé correspond to the North-Patagonian temperate rainforests that are characterized by few tree species of different shade tolerance growing on fragile soils. We discuss the convenience of developing continuous cover forest management for these forests, rather than selective cuts or even-aged management that is proposed in the current legislation. This study is a contribution to forest classification for both ecologically- and forestry-oriented purposes.

  11. Aproximación a la emigración española a la provincia del Chubut: los yacimientos petrolíferos fiscales (1915-1933)

    OpenAIRE

    Castiñeira Castro, Víctor Manuel; Alfredo MARTÍN GARCÍA

    1999-01-01

    La ciudad de Comodoro Rivadavia, enclavada en la actual provincia argentina del Chubut, se convirtió a comienzos del presente siglo, y con motivo del descubrimiento en la zona de importantes yacimientos de petróleo, en un destacado foco de atracción de inmigración. A través del análisis de YPF, la empresa más influyente de la zona, observamos la importancia jugada por la colectividad española en este proceso, así como su carácter de inmigración no especializada tendente a ocupar los empleos m...

  12. Origin and evolution of the Laguna Potrok Aike maar (Patagonia, Argentina)

    Science.gov (United States)

    Gebhardt, A. C.; de Batist, M.; Niessen, F.; Anselmetti, F. S.; Ariztegui, D.; Ohlendorf, C.; Zolitschka, B.

    2009-04-01

    Laguna Potrok Aike, a maar lake in southern-most Patagonia, is located at about 110 m a.s.l. in the Pliocene to late Quaternary Pali Aike Volcanic Field (Santa Cruz, southern Patagonia, Argentina) at about 52°S and 70°W, some 20 km north of the Strait of Magellan and approximately 90 km west of the city of Rio Gallegos. The lake is almost circular and bowl-shaped with a 100 m deep, flat plain in its central part and an approximate diameter of 3.5 km. Steep slopes separate the central plain from the lake shoulder at about 35 m water depth. At present, strong winds permanently mix the entire water column. The closed lake basin contains a sub saline water body and has only episodic inflows with the most important episodic tributary situated on the western shore. Discharge is restricted to major snowmelt events. Laguna Potrok Aike is presently located at the boundary between the Southern Hemispheric Westerlies and the Antarctic Polar Front. The sedimentary regime is thus influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Previous studies demonstrated that closed lakes in southern South America are sensitive to variations in the evaporation/precipitation ratio and have experienced drastic lake level changes in the past causing for example the desiccation of the 75 m deep Lago Cardiel during the Late Glacial. Multiproxy environmental reconstruction of the last 16 ka documents that Laguna Potrok Aike is highly sensitive to climate change. Based on an Ar/Ar age determination, the phreatomagmatic tephra that is assumed to relate to the Potrok Aike maar eruption was formed around 770 ka. Thus Laguna Potrok Aike sediments contain almost 0.8 million years of climate history spanning several past glacial-interglacial cycles making it a unique archive for non-tropical and non-polar regions of the Southern Hemisphere. In particular, variations of

  13. "Jejenes" (Diptera: Simuliidae of Nahuel Huapi National Park, Patagonia, Argentina: Preliminary results "Jejenes" (Diptera: Simuliidae del Parque Nacional Nahuel Huapi, Patagonia, Argentina: Resultados preliminares

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    Luis M. Hernández

    2009-06-01

    Full Text Available The Simuliidae is a family of Diptera with approximately 2072 described species worldwide. The females of the majority of the species feed from vertebrates' blood, which makes them a significant plague that affects both men as well as cattle, birds, and other vertebrates. The objective of this paper is to create an inventory of Simuliidae and to reveal certain aspects of the biology and distribution of this family of aquatic insects in the Nahuel Huapi National Park. Moreover, information on the zoogeography of Simuliidae in Patagonia is provided. Five genera, 3 subgenera and 32 species Simuliidae are recorded from Patagonia: Cnesia (three spp., Cnesiamima (one sp., Gigantodax (14 spp., Paraustrosimulium (one sp., Simulium (Ectemnaspis (one sp., S. (Psaroniocompsa (one sp. and S. ( Pternaspatha (11 spp., At present, we have collected all five genera, one subgenus of Simulium (Pternaspatha, and 19 species of Simuliidae in the park, which amounts to 57% of the Simuliidae fauna in this area. Puerto Blest, a characteristic area of the High-Andean phytogeographical province (humid forest, showed the highest diversity of Simuliidae.Los simúlidos pertenecen a una familia de Diptera (Simuliidae con alrededor de 2.072 especies descritas a nivel mundial. Las hembras de la mayoría de las especies se alimentan con sangre de vertebrados, lo cual las convierte en importantes plagas que afectan tanto al hombre como al ganado, aves y otros vertebrados. Los objetivos de este trabajo son llevar a cabo un inventario de Simuliidae y dar a conocer algunos aspectos de la biología y la distribución de esta familia de insectos acuáticos en el Parque Nacional Nahuel Huapi, Argentina. Además, se proporciona información sobre la biogeografía de Simuliidae en la Patagonia. Cinco géneros, un subgénero y 32 especies de simúlidos han sido registrados para Patagonia: Cnesia (3 spp., Cnesiamima (1 sp., Gigantodax (14 spp., Paraustrosimulium (1 sp., Simulium

  14. SRTM Anaglyph: Meseta de Somuncura, Patagonia, Argentina (Near Los Menucos)

    Science.gov (United States)

    2000-01-01

    The Meseta de Somuncura is a semi-arid basalt plateau in northern Patagonia. This view of the northwestern part of the plateau, near Los Menucos, Argentina, shows numerous depressions where the upper basalt layers are missing or collapsed. Collapse occurs above voids in the underlying rock. These voids might have been caused by lava tubes carrying away molten lava from under the cooled and solidified surface of a lava flow. Alternatively, voids might result when ground water dissolves carbonate (limestone) or evaporite (salt) deposits that the lava may be covering.Many of the depressions have salty lakes. Light wind streaks downwind (eastward) from the lakes show that salt crystals blow off the lake beds during dry times. Some eroded sand and silt debris from the basalt must also blow downwind, but the degree to which wind plays a role in the erosion of the depressions is not clear.This anaglyph was generated by first draping a Landsat Thematic Mapper image over a topographic map from the Shuttle Radar Topography Mission, then producing the two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and the right eye with a blue filter.Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center,Sioux Falls, South Dakota.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11,2000. SRTM used the same

  15. SRTM Stereo Pair: Meseta de Somuncura, Patagonia, Argentina

    Science.gov (United States)

    2000-01-01

    The Meseta de Somuncura is a semi-arid basalt plateau in northern Patagonia. This view of the northwestern part of the plateau, near Los Menucos, Argentina, shows numerous depressions where the upper basalt layers are missing or collapsed. Collapse occurs above voids in the underlying rock. These voids might have been caused by lava tubes carrying away molten lava from under the cooled and solidified surface of a lava flow. Alternatively, voids might result when ground water dissolves carbonate (limestone) or evaporite (salt) deposits that the lava may be covering.Many of the depressions have salty lakes. Light wind streaks downwind (eastward) from the lakes show that salt crystals blow off the lake beds during dry times. Some eroded sand and silt debris from the basalt must also blow downwind, but the degree to which wind plays a role in the erosion of the depressions is not clear.This cross-eyed stereoscopic image pair was generated using topographic data from the Shuttle Radar Topography Mission, combined with an enhanced Landsat 7satellite color image. The topography data are used to create two differing perspectives of a single image, one perspective for each eye. In doing so, each point in the image is shifted slightly, depending on its elevation. When stereoscopically merged, the result is a vertically exaggerated view of the Earth's surface in its full three dimensions.Landsat satellites have provided visible light and infrared images of the Earth continuously since 1972. SRTM topographic data match the 30-meter (99-foot) spatial resolution of most Landsat images and provide a valuable complement for studying the historic and growing Landsat data archive. The Landsat 7 Thematic Mapper image used here was provided to the SRTM project by the United States Geological Survey, Earth Resources Observation Systems (EROS) Data Center,Sioux Falls, South Dakota.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the

  16. Recent drainage events of glacial Lake Cachet 2, Patagonia

    Science.gov (United States)

    Casassa, G.; Wendt, J.; Wendt, A.; Escobar, F.; Lopez, P.; Carrasco, J.; Rivera, A.; Leidich, J.

    2009-04-01

    Lake Cachet 2 (47°12' S, 73°15' W, 422 m a.s.l.) is a proglacial lake of 4 km2 located on the eastern margin of the Northern Patagonia Icefield (3,953 km2, Rivera et al., 2007), which is dammed on its southern margin by Colonia Glacier. Until April 2008 there was no historical evidence of catastrophic flooding of this lake. In 2008 three sudden drainage events occurred at Lake Cachet 2 (April 6-7; October 7-8 and 21-22 December). During each event the flood wave traveled down Colonia River to the confluence with Baker River, then affected Baker River to a distance of up to 25 km upstream from the confluence and downstream all the way to its mouth on the Pacific Ocean fjords at Caleta Tortel (100 km to the southwest), transporting abundant sediments. In April the runoff of Baker River close to the confluence with Colonia River increased from a base level of 1,200 m3/s on April 7 to a peak runoff of 3,570 m3/s within a period of less than 48 hours, resulting in a river level increase of 4.5 m and an associated water temperature drop from 8°C to 4°C. In October the base level was 573 m3/s, with a peak runoff of 3,007 m3/s, a river level increase of 4.7 m and a water temperature drop from 7.3°C to 4.8°C, while in December the corresponding values were 1,145 m3/s, 3,052 m3/s, 11°C and 8°C. The flood affected roads, bridges, farms and cattle, fortunately not resulting in any human damage. Similar floods had been reported on Colonia River several decades ago, the last having occurred in the 1970s, all of which originated at that time at glacial Lake Arco, located south of Colonia Glacier. Airborne and ground explorations carried out after each event in 2008 confirmed that the floods originated at Lake Cachet 2, draining under Colonia Glacier for a distance of 8 km and emerging at the front of the glacier. As a result parts of the glacier front collapsed after each event, where large ice fractures could be observed. During the October event a complete drainage of

  17. Chironomid (Chironomidae: Diptera checklist from Nahuel Huapi National Park, Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    Mariano DONATO

    2008-01-01

    Full Text Available Este trabajo presenta el primer catálogo de taxones modernos y subfósiles de la familia Chironomidae (Insecta: Diptera del Parque Nacional Nahuel Huapi en Patagonia, Argentina. La fauna catalogada contiene 104 especies en 48 géneros y 6 subfamilias para la fauna moderna y 52 morfotipos en 36 géneros y 4 subfamilias para la fauna subfósil.

  18. La proyección colonial de Chile a la Patagonia Insular en el siglo XVIII

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    Urbina Carrasco, María Ximena

    2011-12-01

    Full Text Available In this article, the geopolitical consequences of the shipwreck of the English frigate Wager and the landfall of the ship Anna into the coasts of the Western Insular Patagonia in 1741 are presented, which were part of the fleet of George Anson. The news reporting the English presence in the deserted and unknown insular and coastal territory southernmost Chiloé, and which had disseminated towards the end of the continent, promoted the deployment of different actions tending to make presence noted, such as military and missionary expeditions, fort establishment and area patrols. None of the latter implied a permanent settlement or effective incorporation of such border, although they indeed involved the creation of a «mobile frontier» for Chiloé and the development of a Western Patagonia image.

    Este artículo presenta las consecuencias geopolíticas del naufragio de la fragata inglesa Wager y la recalada de otro barco, el Anna, que formaban parte de la flota de George Anson, en las costas de la Patagonia Occidental Insular en 1741. La noticia de la presencia inglesa en el despoblado y desconocido territorio insular y bordemarino al sur de Chiloé, y que se proyectaba al fin del continente, generó el despliegue de acciones tendentes a marcar presencia, como expediciones militares y misionales, la fundación de un fuerte y el patrullaje por la zona. Nada de esto se tradujo en un asentamiento permanente o incorporación efectiva de dicha frontera, pero si en la conformación de una «frontera móvil» de Chiloé, y la construcción de una imagen de la Patagonia Occidental.

  19. Repeated glacial-lake outburst floods in Patagonia: An increasing hazard?

    OpenAIRE

    Dussaillant, Alejandro; Benito, Gerardo; Buytaert, Wouter; Carling, Paul; Meier, Claudio; Espinoza, Fabián

    2009-01-01

    Five similar glacial-lake outburst floods (GLOFs) occurred in April, October, December 2008, March and September 2009 in the Northern Patagonia Icefield. On each occasion, Cachet 2 Lake, dammed by the Colonia Glacier, released circa 200-million m3 water into the Colonia River. Refilling has occurred rapidly, such that further outbreak floods can be expected. Pipeflow calculations of the subglacial tunnel drainage and 1D hydraulic models of the river flood give consistent results, with an esti...

  20. Cretaceous/Paleogene floral turnover in Patagonia: drop in diversity, low extinction, and a Classopollis spike.

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    Viviana D Barreda

    Full Text Available Nearly all data regarding land-plant turnover across the Cretaceous/Paleogene boundary come from western North America, relatively close to the Chicxulub, Mexico impact site. Here, we present a palynological analysis of a section in Patagonia that shows a marked fall in diversity and abundance of nearly all plant groups across the K/Pg interval. Minimum diversity occurs during the earliest Danian, but only a few palynomorphs show true extinctions. The low extinction rate is similar to previous observations from New Zealand. The differing responses between the Southern and Northern hemispheres could be related to the attenuation of damage with increased distance from the impact site, to hemispheric differences in extinction severity, or to both effects. Legacy effects of the terminal Cretaceous event also provide a plausible, partial explanation for the fact that Paleocene and Eocene macrofloras from Patagonia are among the most diverse known globally. Also of great interest, earliest Danian assemblages are dominated by the gymnosperm palynomorphs Classopollis of the extinct Mesozoic conifer family Cheirolepidiaceae. The expansion of Classopollis after the boundary in Patagonia is another example of typically Mesozoic plant lineages surviving into the Cenozoic in southern Gondwanan areas, and this greatly supports previous hypotheses of high latitude southern regions as biodiversity refugia during the end-Cretaceous global crisis.

  1. Cretaceous/Paleogene floral turnover in Patagonia: drop in diversity, low extinction, and a Classopollis spike.

    Science.gov (United States)

    Barreda, Viviana D; Cúneo, Nestor R; Wilf, Peter; Currano, Ellen D; Scasso, Roberto A; Brinkhuis, Henk

    2012-01-01

    Nearly all data regarding land-plant turnover across the Cretaceous/Paleogene boundary come from western North America, relatively close to the Chicxulub, Mexico impact site. Here, we present a palynological analysis of a section in Patagonia that shows a marked fall in diversity and abundance of nearly all plant groups across the K/Pg interval. Minimum diversity occurs during the earliest Danian, but only a few palynomorphs show true extinctions. The low extinction rate is similar to previous observations from New Zealand. The differing responses between the Southern and Northern hemispheres could be related to the attenuation of damage with increased distance from the impact site, to hemispheric differences in extinction severity, or to both effects. Legacy effects of the terminal Cretaceous event also provide a plausible, partial explanation for the fact that Paleocene and Eocene macrofloras from Patagonia are among the most diverse known globally. Also of great interest, earliest Danian assemblages are dominated by the gymnosperm palynomorphs Classopollis of the extinct Mesozoic conifer family Cheirolepidiaceae. The expansion of Classopollis after the boundary in Patagonia is another example of typically Mesozoic plant lineages surviving into the Cenozoic in southern Gondwanan areas, and this greatly supports previous hypotheses of high latitude southern regions as biodiversity refugia during the end-Cretaceous global crisis.

  2. El caso del Outburst Flood histórico de la laguna Derrumbe, Cholila, Chubut: Colapso de dique Morénico en la Cordillera Norpatagónica The historic outburst flood of the laguna Derrumbe, Cholila, Chubut: Fast glacier retreat and moraine dam failure in North Patagonian Cordillera

    Directory of Open Access Journals (Sweden)

    Bruno Colavitto

    2012-09-01

    Full Text Available La laguna Derrumbe es un cuerpo de agua ubicado en los Andes Norpatagónicos en la provincia de Chubut, Argentina. Está contenida en un circo glaciario y endicada por una morena frontal del glaciar homónimo. A través del reconocimiento de campo se pudo describir a esta laguna y a un importante depósito rocoso que se halla aguas abajo de la misma, interpretado como un depósito de outburst flood. Estos depósitos son generados por procesos de alta energía relacionados con la rotura de un dique natural, en este caso un dique morénico. El estudio realizado permitió concluir que la morena frontal del glaciar Derrumbe sufrió una rotura parcial en tiempos históricos, desatando así una inundación súbita aguas abajo de la laguna, a través del valle del río Tigre, en la localidad de Cholila. En este trabajo se analizaron las posibles causas que dieron lugar a la rotura, la cual probablemente sea producto del rápido retroceso que el glaciar experimentó durante la década del ´50 y principios del ´60. Retroceso comparable con el ocurrido en muchos de los cuerpos glaciares de los Andes Patagónicos durante el último siglo.The Laguna Derrumbe is a body of water located in the North Patagonian Andes, in Chubut province, Argentina. This lake is contained in a glacial cirque and dammed by the terminal moraine of the namesake glacier. Through field survey it was possible to describe this lake and an important rocky deposit downstream of it, which is interpreted as an outburst flood deposit. These deposits are generated by high-energy processes related to the failure of a natural dam, in this case a moraine dam. The study made allowed to conclude that the frontal moraine of the Derrumbe glacier suffered a partial rupture in historic times, unleashing a flash flood downstream to the lake, through the Tigre river valley in the town of Cholila. In this work the possible causes that led to the failure are discussed, concluding that the main cause

  3. Insectos acuáticos de la Meseta del Somuncura, Patagonia, Argentina. Inventario preliminar Aquatic insects from Somuncura plateau, Patagonia, Argentina. Preliminary inventory

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    Javier Muzón

    2005-12-01

    Full Text Available RESUMEN. Se brinda un inventario preliminar de los insectos acuáticos de la Meseta del Somuncura y su área de influencia (Patagonia, Argentina realizado sobre la base de colecciones y registros previos de especies pertenecientes a los órdenes Ephemeroptera, Odonata, Hemiptera (Heteroptera, Trichoptera, Diptera (familias Ceratopogonidae, Culicidae y Psychodidae y Coleoptera. Se han relevado diversos tipos de ambientes en 14 localidades. El número de especies registrado asciende a 78, agrupadas en 51 géneros y 26 familias, de las cuales 33 se citan por primera vez del área. De los taxa registrados 83% de los géneros corresponden a grupos de amplia distribución (neotropicales, americanos o cosmopolitas, mientras que 41% de las especies presentan una distribución patagónica o andina.ABSTRACT. A preliminary inventory of the aquatic insects from the Somuncura plateau and its area of influence (Patagonia, Argentina is presented. It was done on the basis of the study of collections and previous records of species belonging to the orders Ephemeroptera, Odonata, Hemiptera (Heteroptera, Trichoptera, Diptera (families Ceratopogonidae, Culicidae, and Psychodidae and Coleoptera. Different kinds of environments were surveyed in 14 localities. Seventy eigth species grouped in 51 genera and 26 families were registered, and 33 species are new records for the area. Eighty three % of the registered genera are widely distributed (neotropical, american or cosmopolitan, while 41 % of the species exhibit patagonic or andean distribution.

  4. IMÁGENES DE AUTOR E IMÁGENES DE PATAGONIA: TRELEW DE MARCELO ECKHARDT Images of author and images of Patagonia: Trelew by Marcelo Eckhardt

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    Luciana Andrea Mellado

    2010-12-01

    Full Text Available Trelew (1997 del escritor argentino Marcelo Eckhardt está compuesto por ensayos, relatos y una novela que se desarrollan de modo intercalado. Caracterizado por la mixtura genérica, así como por una insistente descripción del espacio geográfico y cultural de PatagoniaTrelew despliega la mitografía de la ciudad homónima a la vez que construye la del propio autor que expande y diversifica su enunciación en otras voces, convirtiendo el texto en un texto plural no sólo en cuanto a las formas sino, también, en cuanto a las voces que lo configuran.Trelew (1997 of the Argentine writer Marcelo Eckhardt is composed by essays, stories and a novel that they develop in an inserted way. Characterized by the generic mixture, and by a insistent description of the geographic and cultural space of the Patagonia, Trelew develops the mitografìa of the city homonym simultaneously that constructs that of the own author who expands and diversifies his speech in other voices, turning the text in a plural text by the forms and by the voices that form it.

  5. Atmospheric background trace elements deposition in Tierra del Fuego region (Patagonia, Argentina), using transplanted Usnea barbata lichens.

    Science.gov (United States)

    Conti, Marcelo Enrique; Finoia, Maria Grazia; Bocca, Beatrice; Mele, Giustino; Alimonti, Alessandro; Pino, Anna

    2012-01-01

    Lichen, Usnea barbata, transplants taken from Tierra del Fuego (south Patagonia, Argentina) were tested as potential biomonitors of atmospheric airborne deposition in an apparently pristine environment. In 2005, lichens were sampled in a reference site (n = 31) and transplanted in the northern Region of Tierra del Fuego. After, respectively, 1 month and 1 year of exposure, we collected them. The aim of the study was to determine the bioaccumulation of 26 elements in order to evaluate the background levels in the selected area. Samples were analyzed by the sector field inductively coupled plasma mass spectrometry. Discriminant analysis on principal component analysis factors was applied in order to explore the relationship among the different elements as far as time and spatial variation in transplants regards. The analysis was tested by Monte Carlo test based on 999 replicates. The most important contamination source resulted to be the atmospheric soil particle deposition. Furthermore, the results were compared with those obtained from the lichens collected in central and southern Tierra del Fuego. This study confirms the ability of U. barbata to reflect the background levels of the 26 elements in that environment. Compared with other background sites in the world, we did confirm that Tierra del Fuego lichens have a low content of the studied elements. Tierra del Fuego turned out not to be a pristine environment as supposed, but it can be considered as a reference basal ecosystem for useful comparisons among different geographical areas. These findings can be very relevant and useful for environmental conservation programs.

  6. Relationship between Bajo Pobre and Chon Aike formations (Deseado Massif, Patagonia, Argentina):a melt inclusions study

    Science.gov (United States)

    Busà, T.; Bellieni, G.; Fernandez, R.; Hecheveste, H.; Piccirillo, E. M.

    2003-04-01

    The Deseado Massif covers the centre-east of the Santa Cruz Province, in the extra-Andean Patagonia. Although the Deseado Massif is mainly composed of silicic volcanic rocks (Chon Aike Formation, CA; 151.5 ±0.5 - 177.8 ±0.4 Ma), mafic and intermediate volcanites (Bajo Pobre Formation, BP; 152.7 ±0.5 and 164 ±0.3 Ma) outcrop largely in the central part of the Massif. In this paper quarz-trapped melt inclusions (rhyolitic in composition) from selected samples of the BP and the CA are analysed. On the basis of major elements content, for BP the sequence from andesite (BP whole rock) to ryholite (trapped as inclusions in quartz) can be modelled by simple fractional crystallisation of ortho- and clinopyroxene, plagioclase, quartz and apatite. As regards trace elements, a good calculated/measured ratio (around 1 ±0.2) is obtained assuming only a relatively high apatite fractionation. Since the apatite fractionation amount is not acceptable for major elements, the evolution of BP Formation cannot be modelled by a simple process of fractional crystallisation, and a contamination process probably occurred. The sequence from BP to CA cannot be modelled by fractional crystallisation. 30% batch melting of BP andesite (BP whole rock) produces a magma from which the CA ryholites (trapped as inclusions in quartz) can be obtained by Rayleigh fractional crystallisation of ortho- and clinopyroxene, plagioclase, magnetite, quartz, apatite and small amounts of zircon and minor allanite. Since the latter one was not observed in the analysed sample, a contamination process during magma evolution cannot be completely excluded. Finally, on the basis of the different trace elements concentration (Nb anomaly, different content in LILE, B/Be and B/Nb), it is possible to suppose that, at the time of the BP and CA emplacement, a changing in the tectonic setting, from subduction to a lithospheric extension, was active.

  7. Formas terminales de Hippidion (Mammalia, Perissodactyla de los yacimientos del Pleistoceno Tardio-Holoceno de la Patagonia (Argentina y Chile

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    Prado, J. L.

    1987-04-01

    Full Text Available The present study is a revision of the terminal forms of the South-American horses coming from the archeological sites of Patagonia. They are compared with those from the Northwest of Argentine. The study also includes paleoenvironmental and cronological related aspects.El presente estudio comprende una revisión de las formas terminales de caballos sudamericanos recuperados de sitios arqueológicos de la Patagonia. Se comparan con las formas del noroeste argentino. Incluye aspectos paleoambientales y cronológicos relacionados.

  8. Capacity building for freshwater insect studies in northern Patagonia, Argentina: DARWIN Initiative programme Biodiversidad de insectos acuáticos en Patagonia Norte, Argentina: programa Iniciativa DARWIN

    Directory of Open Access Journals (Sweden)

    Stephen J. Brooks

    2009-06-01

    Full Text Available This project was funded from September 2006 for three years by the British Government's Darwin Initiative programme. The focus of our project is the study of aquatic insects from Nahuel Huapi National Park (NHNP in Patagonia, Argentina. The park includes a wide range of wetlands, including montane streams, lowland lakes and marshes, distributed within temperate rainforest and arid steppe. The material will be identified and stored in a fully referenced and accessible collection at La Plata Museum and the Natural History Museum, London. Darwin Initiative funding has been used to equip a biodiversity laboratory at National Park Headquarters in Bariloche and also a field station at Puerto Blest. Information on the insect species in NHNP will be entered into a GIS database, together with a vegetation classification and wetland characteristics, to model freshwater insect data spatially and create a biodiversity database, the first of its kind in Patagonia. We hope that the experiences we gain during the project, the insect collections and databases, the publications, and the many other products, will be used to further enhance wetland conservation throughout Argentina and southern South America.Este proyecto fue financiado durante un período de tres años, desde septiembre de 2006 a través de la Iniciativa Darwin del gobierno Británico. El objetivo de este trabajo es el estudio de los insectos acuáticos del Parque Nacional Nahuel Huapi (PNNHP, Patagonia, Argentina. El parque incluye una gran variedad de hábitats que comprenden arroyos, ríos y lagos los cuales se distribuyen desde el bosque siempreverde frío, hasta la zona árida de estepa. Todo el material será identificado y depositado en las colecciones del Museo La Plata y el Museo de Historia Natural de Londres. Los fondos de la Iniciativa Darwin han sido utilizados para equipar un laboratorio de biodiversidad en las oficinas del PNNHP en Bariloche y la estación de investigación en

  9. Extensive MIS 3 glaciation in southernmost Patagonia revealed by cosmogenic nuclide dating of outwash sediments

    Science.gov (United States)

    Darvill, Christopher M.; Bentley, Michael J.; Stokes, Chris R.; Hein, Andrew S.; Rodés, Ángel

    2015-11-01

    The timing and extent of former glacial advances can demonstrate leads and lags during periods of climatic change and their forcing, but this requires robust glacial chronologies. In parts of southernmost Patagonia, dating pre-global Last Glacial Maximum (gLGM) ice limits has proven difficult due to post-deposition processes affecting the build-up of cosmogenic nuclides in moraine boulders. Here we provide ages for the Río Cullen and San Sebastián glacial limits of the former Bahía Inútil-San Sebastián (BI-SSb) ice lobe on Tierra del Fuego (53-54°S), previously hypothesised to represent advances during Marine Isotope Stages (MIS) 12 and 10, respectively. Our approach uses cosmogenic 10Be and 26Al exposure dating, but targets glacial outwash associated with these limits and uses depth-profiles and surface cobble samples, thereby accounting for surface deflation and inheritance. The data reveal that the limits formed more recently than previously thought, giving ages of 45.6 ka (139.9/-14.3) for the Río Cullen, and 30.1 ka (+45.6/-23.1) for the San Sebastián limits. These dates indicate extensive glaciation in southern Patagonia during MIS 3, prior to the well-constrained, but much less extensive MIS 2 (gLGM) limit. This suggests the pattern of ice advances in the region was different to northern Patagonia, with the terrestrial limits relating to the last glacial cycle, rather than progressively less extensive glaciations over hundreds of thousands of years. However, the dates are consistent with MIS 3 glaciation elsewhere in the southern mid-latitudes, and the combination of cooler summers and warmer winters with increased precipitation, may have caused extensive glaciation prior to the gLGM.

  10. Mass balance of Nef glacier (Patagonia) by means of laser altimetry

    Science.gov (United States)

    Lopez, P.; Casassa, G.; Wendt, J.; Wendt, A.; Delclaux, F.

    2009-04-01

    Glaciers of Southern Patagonia Icefield (SPI) and Northern Patagonia Icefield (NPI) have shown an enhanced wasting and an increased melting in recent decades, mainly in reaction to regional warming. In consequence, water resources originating from those glaciers are also affected by their negative mass balance. Mass balance measurements provide information about the mass changes of both the accumulation and the ablation zones. A main limitation in attempting estimations of glacier mass balance of the NPI (4,197 km²) and the SPI (13,000 km²) is the difficulty in performing field observations, particularly within the accumulation areas, largely because of unfavourable meteorological conditions as well as the limitations due to the large size of the icefields. There is thus a need for carrying out detailed analyses of individual representative glaciers in Patagonia, covering both the ablation and accumulation areas. The Nef Glacier (138 km² in February 2005), is one of the largest and most representative glaciers of the eastern side of the NPI. During the last century it has been retreating and losing mass, and its evolution has been similar to other large glaciers of the NPI. Moreover, the Nef River is one of the most important tributaries of the Baker River, the largest drainage basin in the region and the river with the highest discharge in Chile. In this paper we present results of mass balance (2008 - 2009) of Nef glacier estimated using the geodetic method, where Digital Elevation Models (DEMs) of the glacier constructed at different dates are compared. The DEMs have been constructed using data from airborne laser altimetry with CECS Airborne Laser Scanner (Wendt et al., 2008), which has the advantage over airborne photogrammetry that it involves less data processing and practically no ground control, yielding excellent sub-meter precision.

  11. Hepatitis Infecciosa Necrosante en ovinos Merino de la Patagonia argentina, parasitados con Thysanosoma actinioides Black Disease in Merino sheep infected with Thysanosoma actinioides in Patagonia Region, Argentina

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    C.A. Robles

    2000-01-01

    Full Text Available Se describe un brote de hepatitis infecciosa necrosante en un rebaño Merino de la Patagonia Argentina, en donde de 1200 ovejas mueren 80 de ellas (6,7% en forma súbita. Los hallazgos de necropsia más llamativos fueron la gran cantidad de líquido en cavidades torácica y peritoneal, áreas de necrosis coagulativa en el parénquima hepático y la abundante cantidad de Thysanosoma actinioides en canalículos biliares y colédoco. En improntas de hígado se identificó Clostridium novyi mediante inmunofluorescencia. De este mismo órgano se aisló posteriormente Clostridium novyi tipo B. Ante la falta del predisponente más comúnmente citado, Fasciola hepatica, se postula que el severo parasitismo por Thysanosoma actinioides fue el factor desencadenante de este brote de hepatitis infecciosa necrosanteAn outbreak of Black disease in Argentinean Patagonia where 80 sheep out of 1200 Merino ewes suddenly died, is reported. Big amounts of fluid in the thoracic and abdominal cavities, the presence of focal coagulative necrosis in the liver parenchyma and plenty Thysanosoma actinioides specimens in bile ducts were the most important findings observed at necropsy. Clostridium novyi was early detected in liver smears through immunofluorescence. Later, Clostridium novyi type B was isolated from liver cultures. Due to the absence of the commonest predisposing agent, i.e. Fasciola hepatica, the severe parasitism by Thysanosoma actinioides is proposed as the predisposing factor of the present outbreak of Black disease

  12. Chondrichthyans of the San Matías Gulf, Patagonia, Argentina Los condrictios del Golfo San Matías, Patagonia, Argentina

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    María R PERIER

    2011-12-01

    Full Text Available The San Matías Gulf (SMG; 41°- 42° S; 64°- 65° W is the largest gulf in Northern Patagonia, Argentina. Up to date, the chondrichthyan fauna of this area has not been reported. Therefore, the aim of this work is to provide a list with species presence and biological characteristics of the chondrichthyans recorded in SMG during the last 30 years. A total of 13 sharks distributed in 11 families, 19 skates and rays distributed in six families, and one holocephalan have been so far recorded in SMG. From the zoogeographical point of view, this chondrichthyan fauna is a mixed assemblage of species typically found in the Argentinean and Magellanean Provinces. The holocephalan Callorhinchus callorynchus is the most landed chondricthyan of the local fishery. With it, five sharks and seven skates are also exploited.El Golfo San Matías (SMG; 41°- 42° S - 64°-65° O se encuentra ubicado en el norte de la Patagonia, Argentina. Hasta la fecha no se cuentan con reportes de la fauna de condrictios de esta zona. Por lo tanto, el objetivo de este trabajo es proporcionar una lista de la presencia y las características biológicas de los condrictios registrados en el SMG durante los últimos 30 años. Un total de 13 tiburones distribuidos en 11 familias, 19 batoideos distribuidos en seis familias y un holocefalo han sido reportados para la zona. Desde el punto de vista zoogeográfico, el SMG presenta un ensamble de especies pertenecientes a las Provincias Magallánica y Argentina. El holocefalo Callorhinchus callorynchus es el condrictio más desembarcado de la pesquería local. Con menor importancia son explotadas comercialmente, cinco especies de tiburones y siete de rayas.

  13. Lake-level variations and tides in Lago Argentino, Patagonia: insights from pressure tide gauge records

    OpenAIRE

    2015-01-01

    Based on precise pressure tide gauge observations lake-level records are derived for two sites in Lago Argentino, southern Patagonia, of 2.5 and 1 years of duration. Applying the tools of time series analysis, the principal processes affecting the lake level are identified and quantified. Lake-level changes reflecting variations in lake volume are dominated by a seasonal cycle of 1.2 m in amplitude. Lake-volume changes occur in addition with a daily period in response to melt water influx fro...

  14. Magnetotelluric survey to characterize the Sunnyside porphyry copper system in the Patagonia Mountains, Arizona

    Science.gov (United States)

    Rodriguez, Brian D.; Sampson, Jay A.

    2010-01-01

    The Sunnyside porphyry copper system is part of the concealed San Rafael Valley porphyry system located in the Patagonia Mountains of Arizona. The U.S. Geological Survey is conducting a series of multidisciplinary studies as part of the Assessment Techniques for Concealed Mineral Resources project. To help characterize the size and resistivity of the mineralized area beneath overburden, a regional east-west magnetotelluric sounding profile was acquired. This is a data release report of the magnetotelluric sounding data collected along the east-west profile; no interpretation of the data is included.

  15. Audio-magnetotelluric survey to characterize the Sunnyside porphyry copper system in the Patagonia Mountains, Arizona

    Science.gov (United States)

    Sampson, Jay A.; Rodriguez, Brian D.

    2010-01-01

    The Sunnyside porphyry copper system is part of the concealed San Rafael Valley porphyry system located in the Patagonia Mountains of Arizona. The U.S. Geological Survey is conducting a series of multidisciplinary studies as part of the Assessment Techniques for Concealed Mineral Resources project. To help characterize the size, resistivity, and skin depth of the polarizable mineral deposit concealed beneath thick overburden, a regional east-west audio-magnetotelluric sounding profile was acquired. The purpose of this report is to release the audio-magnetotelluric sounding data collected along that east-west profile. No interpretation of the data is included.

  16. Rime Mushrooms - Extreme Rime Ice Buildup on Mountain Summits of Southern Patagonia

    Science.gov (United States)

    Whiteman, C. D.

    2015-12-01

    The Southern Patagonian Andes are known among mountain climbers for a meteorological phenomenon that occurs there but is unknown in many other mountain areas. The phenomenon is the buildup of rime ice in large bulbous or mushroom-shaped accretions on the windward side of projecting mountain summits, ridges and exposed near-vertical rock faces. These "ice mushrooms" have never been investigated scientifically. This talk will introduce the audience to ice mushrooms, describe where they are found, consider the meteorological factors leading to their formation, and illustrate how they are negotiated by mountain climbers using photographs and descriptions from Southern Patagonia.

  17. Outburst floods of glacial lakes in Patagonia: is there an increasing trend?

    Science.gov (United States)

    Casassa, Gino; Wendt, Jens; Wendt, Anja; López, Paulina; Schuler, Thomas; Maas, Hans-Gerd; Carrasco, Jorge; Rivera, Andrés.

    2010-05-01

    Glaciers in Patagonia are temperate and many of them are receding at an accelerated rate, with a consequent enlargement of glacial lakes. We will review the occurrence of Glacial Lake Outburst Floods (GLOFs) recorded during the last century in Patagonia (Northern and Southern Patagonia icefields), and analyse them in view of the general warming of 0.5°C affecting the region during the last 40 years. Special attention will be devoted to Lake Cachet 2 (47°12' S, 73°15' W, 422 m a.s.l.) which has experienced 6 GLOF events during the last 2 years: April 6-7 2008, October 7-8 2008, 21-22 December 2008, 5 March 2009, 16 September 2009 and 5-6 January 2010. Lake Cachet 2 has an area of 4 km2, located on the eastern margin of the Northern Patagonia Icefield, being dammed on its southern margin by Colonia Glacier. Prior to the April 2008 event there had been no historical record of catastrophic flooding of this lake. Each event resulted in a flood wave of which travelled down Colonia River to the confluence with Baker River in a period of less than 48 hours, where it reached peak flows of approximately 2,000 m3/s. Here we present airborne and ground explorations carried out in the period 2008-2009 which confirm that the Lake Cachet 2 floods drain through an englacial tunnel under Colonia Glacier for a distance of 8 km, emerging at the front of the glacier. We propose that the lake started draining in 2008 as a result of the weakening of the ice dam produced by long-term thinning of Colonia Glacier. Measurements of the empty lake bed were performed with the CECS airborne laser scanner onboard a helicopter, which show that the maximum water volume of the lake is 200 x 106 m3. Modelling of the flood events has been carried out based on the subglacial flood model of Clarke (2003), showing that a semi-circular subglacial tunnel attaining a maximum dimension of 15 m can evacuate Lake Cachet 2 in approximately 48 hours, with peak flows on the order of 4000 m3/s. Preliminary

  18. Diversos usos instrumentales del aparato masticatorio en restos humanos de la Patagonia Argentina

    Directory of Open Access Journals (Sweden)

    Kozameh, Livia Febes

    2005-01-01

    Full Text Available Desgastes dentarios atípicos y disarmónicos, asociados a patologías sugirieron la posibilidad que los mismos se hubieran producido por una actividad masticatoria excesiva y no alimentaria. La variedad de rastros registrados sugiere el uso de la boca con fines instrumentales, como recurso posiblemente constante. Los casos seleccionados son seis y sus rasgos predominantes se describen sucintamente. 1 Muestra dentaria de canoeros fueguinos. Fracturas cuspídeas pulimentadas únicamente en denticiones femeninas.2Resto de cazador canoero del Beagle. Notables desgastes dentarios con distintas angulaciones a modo de zigzag. Raíces en función oclusal con procesos alveolares concomitantes. 3Resto de cazador pedestre de Tierra del Fuego. Disminución del tamaño coronal de los dientes anteriores y primeros premolares, con pérdida completa de su morfología. Los bordes incisales exhiben tres planos de desgaste con diferentes direcciones. 4 y 5Cazadores de Santa Cruz. En uno de ellos los desgastes coronales son convexos en todos sus dientes. Patologías alveolares. En el otro ejemplar el desgaste tornó cilíndricas las coronas de las piezas anteriores. 6Resto femenino de Chubut. Pérdida prematura de los cuatro dientes anteriores con compromiso óseo y canino transpuesto.

  19. Jurassic tetrapods and flora of Cañadón Asfalto Formation in Cerro Cóndor area, Chubut Province Flora y tetrápodos del Jurásico de la Formación Cañadón Asfalto en el área de Cerro Cóndor, provincia de Chubut

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    Ignacio H. Escapa

    2008-12-01

    Full Text Available The plant and tetrapod fossil record of the Cañadón Asfalto Formation (Middle to Late Jurassic found in Cerro Cóndor area (Chubut Province is summarized here. The flora is dominated by conifers (Araucariaceae, Cupressaceae sensu lato but also includes ferns and equisetaleans. The tetrapod fauna is composed of dinosaur taxa described in the 70's as well as other remains recently described and other vertebrate groups such as amphibians, turtles, and mammals. The amphibian remains have been interpreted as representatives of a new species of Notobatrachus, considered one of the most basal members of the anuran lineage. Similarly, turtle remains have been recently recognized as a new species of basal turtle, bringing valuable information about the early evolution of this group. The dinosaur remains are largely dominated by saurischian taxa, represented by basal forms of Eusauropoda and Tetanurae. In addition, three different mammalian species have been identified and considered as early representatives of an endemic Gondwanan mammalian fauna. The fossil record of this formation represents the most completely known biota from the continental Middle to Late Jurassic of the Southern Hemisphere and one of the most complete of the entire world.Se resume brevemente el registro de plantas y tetrápodos fósiles de la Formación Cañadón Asfalto (Jurásico Medio a Superior en el área de Cerro Cóndor, provincia de Chubut. La flora está conformada por coníferas de las familias Araucariaceae y Cupressaceae sensu lato dominando la asociación, la cual se completa con helechos y equisetales en proporciones menores. La fauna de tetrápodos se compone por los clásicos dinosaurios descriptos en los 70`s, a los que se suman nuevos restos pertenecientes a este grupo, así como anfibios, tortugas y mamíferos coleccionados en la última década. Los restos de anfibios han sido interpretados como representantes de una nueva especie de Notobatrachus, considerado

  20. Examen paleobiológico de sedimentos asociados a restos humanos hallados en el sitio arqueológico Alero Mazquiarán, Chubut, Argentina Paleobiological Analysis Of Sediments Associated With Human Remains Found At The Archaeological Site Of Alero Mazquiarán, Chubut Province, Argentina

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    Martín H. Fugassa

    2008-12-01

    Full Text Available Se analizaron sedimentos de la cavidad abdominal de un esqueleto perteneciente a un enterratorio múltiple del sitio Alero Mazquiarán, provincia de Chubut, Argentina. El fechado asociado arrojó una antigüedad de 212 ± 35 años. En el estudio macroscópico de dichos sedimentos fueron identificadas fecas de roedor, pupas de dípteros y otros restos de artrópodos. Los fragmentos macroscópicos pertenecientes a artrópodos fueron colectados y examinados bajo lupa. Se procesaron 5 g de sedimento y se realizó flotación en solución sobresaturada de sacarosa para recuperar ácaros. Asimismo, parte del sedimento fue procesado mediante la técnica de Stoll modificada por Fugassa y colaboradores para cuantificar la presencia de ácaros. Se identificaron puparios de Diptera, Familias Calliphoridae y Piophilidae, y de Lepidoptera, Familia Tineidae. También se reconocieron restos de Coleoptera, Familia Dermestidae. Al microscopio óptico se identificaron numerosos inmaduros de ácaros Astigmata, Familia Saproglyphidae, así como individuos adultos de Mesostigmata, Familia Ichthyostomatogasteridae y Oribatida, Familias Oppiidae y Cosmochthoniidae. En las fecas de roedor se hallaron ácaros Heterostigmata, Familia Tarsonemidae e hipopus de Astigmata no determinados. Los resultados permitieron obtener una interpretación del proceso de inhumación y de las condiciones ambientales en que transcurrió. Se sostiene la importancia de la recuperación de los sedimentos asociados a los materiales arqueológicos para los estudios bioculturales.Sediments found in the pelvic girdle of a human skeleton from a multiple burial at the archaeological site of Alero Mazquiarán, Chubut Province, Argentina, were analyzed. Samples were dated to 212 ± 35 years old. Rodent feces, dipteran pupae, and arthropod body parts were identified after macroscopic and stereomicroscopic analyses. A 5 g sub-sample of sediment was treated by floating in over-saturated sucrose solution

  1. Aproximación a la emigración española a la provincia del Chubut: los yacimientos petrolíferos fiscales (1915-1933

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    Castiñeira Castro, Víctor Manuel

    1999-12-01

    Full Text Available La ciudad de Comodoro Rivadavia, enclavada en la actual provincia argentina del Chubut, se convirtió a comienzos del presente siglo, y con motivo del descubrimiento en la zona de importantes yacimientos de petróleo, en un destacado foco de atracción de inmigración. A través del análisis de YPF, la empresa más influyente de la zona, observamos la importancia jugada por la colectividad española en este proceso, así como su carácter de inmigración no especializada tendente a ocupar los empleos menos reconocidos en la empresa.

  2. Sweet cherries from the end of the world: options and constraints for fruit production systems in South Patagonia, Argentina

    NARCIS (Netherlands)

    Cittadini, E.D.

    2007-01-01

    In South Patagonia, development of the fruit production sector has been almost exclusively based on the production of sweet cherry, with an area increase from 176 ha in 1997 to 578 ha at the end of 2006. These orchards are designed as intensive systems and oriented to export markets. Even though swe

  3. The Odonata (Insecta) of Patagonia: a synopsis of their current status with illustrated keys for their identification.

    Science.gov (United States)

    Muzón, Javier; Pessacq, Pablo; Lozano, Federico

    2014-03-31

    Patagonia is a vast landmass with a distinctive environmental and biotic heterogeneity. Its Odonata biodiversity is the best known of South America, and it is composed of 36 species, of which more than 50% are endemic. We summarize the main taxonomic, distributional and biological information including illustrated keys for adults and known larvae, and distributional maps.

  4. Inter-subjectivity and Domestication in the Making of a Global Region: Territorialization of Salmon in the Chilean Patagonia.

    NARCIS (Netherlands)

    Blanco, Gustavo; Arce, A.M.G.; Fisher, E.F.

    2016-01-01

    This article examines transformations in the Chilean Patagonia, a region that has become a world leader in Salmon production for global markets. Employing ethnographic methods, this study examines the possibilities of considering inter-subjectivities in the processes of conforming important regions

  5. PALEOCLIMAS Y PALEOESCENARIOS EN LA PATAGONIA AUSTRAL Y EN TIERRA DEL FUEGO DURANTE EL CUATERNARIO

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    Andrea Coronato

    2007-12-01

    Full Text Available Se presentan evidencias geomorfológicas y palinológicas indicadoras de paleoescenarios existentes en los últimos dos millones de años en el extremo sur de Patagonia y Tierra del Fuego. Estos procesos indican la ocurrencia de cambios climáticos no forzados por intervención humana en la atmósfera. Los períodos fríos habrían sido progresivamente menos intensos desde la Gran Glaciación Patagónica, ocurrida hace 1 millón de años. Durante el Holoceno y los tiempos históricos, las glaciaciones se restringieron a las zonas superiores a los 900 m s.n.m. y el deterioro climático no habría afectado significativamente al ecosistema bosque ubicado a menos de 400 m s.n.m. Un importante período cálido ocurrido en tiempos históricos fue registrado en las zonas de altura en Patagonia Norte y en las cercanías al nivel del mar en Tierra del Fuego

  6. Last glacial maximum environments in northwestern Patagonia revealed by fossil small mammals

    Science.gov (United States)

    Tammone, Mauro N.; Hajduk, Adan; Arias, Pablo; Teta, Pablo; Lacey, Eileen A.; Pardiñas, Ulyses F. J.

    2014-07-01

    Comparisons of historical and modern assemblages of mammals can yield important insights into patterns and processes of environmental change. Here, we present the first analyses of small mammal assemblages present in northern Patagonia during the last glacial maximum (LGM). Using remains obtained from owl pellets excavated from an archeological cave site (Arroyo Corral I, levels VII-V, carbon dates of 22,400-21,530 cal yr BP), we generate estimates of the minimum number of individuals for all species detected; these estimates, in turn are used to determine relative species abundances. Comparisons of these data with similar analyses of small mammal remains obtained from a second archeological site (ACoII, levels IV-V, carbon dates of 10,010-9220 cal yr BP) as well as from modern owl pellets reveal pronounced changes in relative species abundance since the LGM. In particular, Euneomys chinchilloides and Ctenomys sociabilis - the predominant species during the LGM - declined markedly, suggesting a change from open, bare habitat punctuated by patches of wet meadows and shrubs to the more densely vegetated mosaic of ecotone habitats found in this region today. These data provide important new insights into the environmental changes that have occurred in northern Patagonia over the last 20,000 years.

  7. Nutritional status and obesity in children and young adults with disabilities in Punta Arenas, Patagonia, Chile.

    Science.gov (United States)

    Vélez, Juan C; Fitzpatrick, Annette L; Barbosa, Clara I; Díaz, Mauricio; Urzua, Miyochi; Andrade, Asterio H

    2008-12-01

    Childhood obesity is reaching epidemic proportions throughout the world; however, little is known on the nutritional status of children with disabilities. To address this issue, medical records of 748 children aged 18 years or younger receiving physical therapy during 2004-2005 at a privately sponsored free rehabilitation clinic in Punta Arenas, Patagonia, Chile were abstracted. Data included demographic, clinical, and anthropometric information recorded at the first visit. As a comparison, height and weight were also collected in 215 children attending local schools. Nutritional status was calculated as body mass index (above 6 years of age) or evaluated by growth curves (6 years of age or below) as undernourished, normal, overweight, obese, or morbidly obese. Logistic regression was used to determine risk factors for obesity in these children. Overall, a significant difference in nutritional status between disabled and non-disabled children was found (Pcerebral palsy were less than half as likely to be obese than non-disabled children (OR: 0.46, 95% CI: 0.20-1.03). We conclude that overnutrition continues to be a problem for both disabled and non-disabled children in Patagonia. Programs to increase physical activity and improve nutrition are needed in this isolated part of the world.

  8. LA PATAGONIA EN EL CONTEXTO DE LAS TRANSFORMACIONES REGIONALES.

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    Beatriz Saint Lary

    1993-12-01

    Full Text Available La reestructuración económica internacional en curso, producto de la crisis de expansión del capitalismo, es un eje indispensable para la comprensión de los fenómenos regionales, y puede caracterizarse sintéticamente con las palabras de E. Laurelli y J. Linden-boim: "...se asienta en un proceso de continua centralización del capital, de aceleración de la utilización de los avances científico-técnicos, de mayor participación de los Estados en asociaciones supranacionales; de fortalecimiento de grandes grupos económicos locales; de intensificación de los lazos dependientes de nuestros países con los países capitalistas centrales dentro de los cuales se destacan los efectos del endeudamiento externo; la difusión de políticas de ajuste, básicamente asentadas en orientaciones neoliberales." En este marco, el rol del Estado ha cambiado fundamentalmente su perfil en América Latina, a partir de la "imposición de una imagen antiestatista y la aplicación de medidas que achican, degradan y desmembran el aparato estatal en tamaño y atribuciones" (¡bidem a diferencia del papel regulador y de control social que mantiene e los países centrales, especialmente de Europa occidental, y la tendencía a un mayor intervencionismo que se está dando en Estados Unidos.

  9. Tipología predial del sector productor de cerezas del sur de la Patagonia argentina Farm typology of the sweet cherry production sector of southern Argentinean Patagonia

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    E. Righi

    2011-06-01

    Full Text Available La identificación de tipologías prediales es una herramienta útil para sintetizar la diversidad intrínseca de cada sistema de producción y puede ser eficientemente usada para realizar una selección racional y metódica de las fincas representativas en el contexto de proyectos de investigación y extensión. Sin embargo, las metodologías que se utilizan más comúnmente para producir una tipología presentan algunas características que limitan su aplicación expeditiva para la selección de fincas piloto. El objetivo de este trabajo fue realizar una identificación cuantitativa y una caracterización de tipologías prediales, sobre la base de análisis multivariado de fincas productoras de cerezas en el sur de la Patagonia argentina. Se aplicó una metodología innovadora combinando escala multidimensional, análisis de conglomerados y análisis de porcentajes de semejanza, sobre la base de la cual se identificaron seis diferentes tipos de fincas. Las ventajas de este método para la selección de fincas representativas son mostradas y discutidas a través de la individuación de una finca piloto dentro de cada tipo.Farm typology identification is a useful tool to summarize the diversity that is intrinsic to every farming system and it can be efficiently used to carry out a rational and methodical selection of representative farms within the context of research and extension projects. However, the methodologies that are most commonly used to produce a typology present some features that limit its expeditious application for the selection of pilot farms. The objective of this study was to make a quantitative identification and characterization of farm typologies based on multivariate analysis of the farms of southern Argentinian Patagonia that grow sweet cherry. An innovative methodology which combines multidimensional scaling, cluster analysis and similarity percentages analysis was applied and six relevantly different farm types were

  10. Nueva especie de Planorbidae (Gastropoda: Basommatophora en la Patagonia chilena: Biomphalaria cristiani sp. nov. First record of Planorbidae (Mollusca: Basommatophora in Chilean Patagonia: Biomphalaria cristiani sp. nov.

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    Carmen Fuentealba

    2012-11-01

    Full Text Available En Chile la familia Planorbidae está representada por el género Biomphalaria Preston, 1910, compuesta por siete especies distribuidas desde Isluga hasta el río Puelo. De estas especies, solo B.peregrina, ampliamente distribuida en el neotrópico, y Biomphalaria aymara de Isluga, han sido reconocidas sobre la base de la morfología del sistema reproductor y la rádula, caracteres que fueron utilizados en el presente estudio para diferenciar a Biomphalaria cristiani como nueva especie del grupo y primer registro de la familia en la Patagonia chilena, ampliando su actual rango de distribución. Los caracteres que permiten la diagnosis de B. cristiani son el saco vaginal vestigial truncado, ausencia del desarrollo de los músculos suspensores del pene, vaina del pene corta en relación al prepucio, oviducto largo en relación al espermioducto y vaso deferente más delgado y largo que la vaina del pene, de tamano similar al prepucio. La localidad tipo de Biomphalaria cristiani sp. nov. es Laguna Cisnes (47°7'10.02"S, 72°27'40.65"W, región de Aysén.The family Planorbidae in Chile is represented by the genus Biomphalaria Preston, 1910, consisting of seven species distributed from Isluga to Puelo River. Of these species, only Biomphalaria peregrina widely distributed in the neotropical and Biomphalaria aymara from Isluga are recognized based on the morphology of the reproductive system and radula, characters that were used in the following study to differentiate Biomphalaria cristiani as a new species of this group and first record of the family in Chilean Patagonia, extending its current distribution range. The characters for the diagnosis of B. cristiani are: truncated vestigial vaginal pouch, lack of development of the penis retractor muscles, penis sheath shorter than the prepuce, oviduct longer than the spermiduct and vas deferens thinner and longer than the penis sheath, similar size to the prepuce. The type locality of B. cristiani nov. sp

  11. Early population differentiation in extinct aborigines from Tierra del Fuego-Patagonia: ancient mtDNA sequences and Y-chromosome STR characterization.

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    García-Bour, Jaume; Pérez-Pérez, Alejandro; Alvarez, Sara; Fernández, Eva; López-Parra, Ana María; Arroyo-Pardo, Eduardo; Turbón, Daniel

    2004-04-01

    Ancient mtDNA was successfully recovered from 24 skeletal samples of a total of 60 ancient individuals from Patagonia-Tierra del Fuego, dated to 100-400 years BP, for which consistent amplifications and two-strand sequences were obtained. Y-chromosome STRs (DYS434, DYS437, DYS439, DYS393, DYS391, DYS390, DYS19, DYS389I, DYS389II, and DYS388) and the biallelic system DYS199 were also amplified, Y-STR alleles could be characterized in nine cases, with an average of 4.1 loci per sample correctly typed. In two samples of the same ethnic group (Aonikenk), an identical and complete eight-loci haplotype was recovered. The DYS199 biallelic system was used as a control of contamination by modern DNA and, along with DYS19, as a marker of American origin. The analysis of both mtDNA and Y-STRs revealed DNA from Amerindian ancestry. The observed polymorphisms are consistent with the hypothesis that the ancient Fuegians are close to populations from south-central Chile and Argentina, but their high nucleotide diversity and the frequency of single lineages strongly support early genetic differentiation of the Fuegians through combined processes of population bottleneck, isolation, and/or migration, followed by strong genetic drift. This suggests an early genetic diversification of the Fuegians right after their arrival at the southernmost extreme of South America.

  12. Effects of Post-Fire Plant Cover in the Performance of Two Cordilleran Cypress ( Austrocedrus chilensis) Seedling Stocktypes Planted in Burned Forests of Northeastern Patagonia, Argentina

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    Urretavizcaya, María F.; Gonda, Héctor E.; Defossé, Guillermo E.

    2017-03-01

    Cordilleran cypress ( Austrocedrus chilensis [D.Don] Pic. Serm. et Bizarri) forests occupy 140,000 ha along a sharp environmental gradient of central Andean-Patagonia in Argentina. Every summer, about 3200 ha of these forests are affected by wildfires, taking thereafter long time to recover. To accelerate forest recovery, we determined in xeric and mesic cypress stands burned 5 and 2 year before whether survival and growth of two planted cypress seedling stocktypes are affected by plant cover and contrasting precipitation conditions. Two experiments were conducted on each site, involving 100 replicates of two seedling stocktypes, having each significantly different morphological attributes. The experiments comprised a dry and humid growing season on each site. Both stocktypes performed similarly within stands, but differently between stands. In the xeric stand, plant cover had neutral effects on seedling survival, favored seedling height growth in the dry season, and was negative on collar diameter and stem growth. In the mesic site, high plant cover favored survival and height growth, but was inconsequential for collar diameter and stem growth. In this short-term post-fire period, and independent of precipitation received during both seasons (dry or humid), plant cover appears as playing a facilitative role, having neutral or even positive effects on survival and growth of planted seedlings. During the early post-fire successional stages, and besides seedling stocktype, there was a synergistic balance between light and soil moisture that seems to benefit planted seedling performance in burned cypress forests, and especially in mesic sites.

  13. Estado actual del conocimiento de la familia Ceratopogonidae en la Patagonia (Diptera: Nematocera

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    Gustavo R. SPINELLI

    2009-01-01

    Full Text Available Ceratopogonidae incluye pequeños dípteros nematocerosque crían en hábitats acuáticos o semiacuáticos. Hasta los ‘80, el conocimiento de su taxonomía en la Patagonia se hallaba limitado a la contribución de los comienzos de los ‘30 de Ingram y Macfie, sobre la base de material capturado en 1926-27, en el área del Parque Nacional Nahuel Huapi y zonas vecinasde Chile. En los últimos 25 años, se pusieron en marcha diferentes proyectos, resultando la descripción o registro de numerosos taxones para la región. Si se contabilizan los datos publicados, 102 especies habitan en la Patagonia, de las cuales 86 (84,31% son endémicas para la región. Este alto porcentaje es evidente en los bosques de Nothofagus, con 71 especies endémicas de estebioma, nueve lo son de la estepa y seis presentan registros en bosque y estepa. Datos aún no publicados concuerdan con este esquema. Diecinueve géneros están representados en la Patagonia, diez de ellos con amplia distribución,tres de distribución transantártica y seis son endémicos para el área. Para la misma, se hallan publicadas las revisiones de Forcipomyia, Atrichopogon, Borkenthelea, Macrurohelea y Paradasyhelea; se han finalizado y aún no publicado aquellas de Dasyhelea y Palpomyia, está muy avanzada la de Stilobezzia y se prevé comenzar con las de Austrohelea, Austrosphaeromias, Physohelea y Bezzia. Se calcula que estos datos no divulgados contienen al menos 55 especies todavía no descriptas. Con respecto a los aspectos biogeográficos se pueden destacar estudios que tienden a establecer relaciones entre las áreas reconocidas en esquemas biogeográficos propuestos para la región andina.

  14. Recent Ice thickness helicopter borne radar surveys in Patagonia

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    Rivera, Andres; Zamora, Rodrigo; Andres Uribe, Jose; Oberreuter, Jonathan; Gacitua, Guisella; Rignot, Eric

    2014-05-01

    The Patagonian icefields are the biggest temperate ice bodies in southern hemisphere, which have experienced important areal shrinkage and thinning in recent decades, significantly contributing to sea level rise. The main driving factor behind this retreating condition is recent decade atmospheric warming explaining higher melting rates and equilibrium line altitude upward migration. Ice dynamic is also playing an important role especially in glaciers calving into deep fjords or lakes, type of glaciers that are predominant in the Patagonian icefields. In order to better understand their ice dynamics, several recent works have measured ice velocities using feature tracking and other techniques, however, ice thickness is still barely known. In spite of several on the ground radar measurements successfully detecting several hundred of m of ice thickness at the higher plateaus, this variable remains the great missing part of the equation especially when the thickness is approximately deeper than 600 m or where the glacier surfaces are very crevassed or nearby the Equilibrium line Altitude, where on the ground measurements are logistically constrained. In order to tackle the lack of thickness data, a helicopter borne radar system was used to survey several Patagonian temperate glaciers calving into fjords (Glaciares San Rafael and Jorge Montt) or lakes (Nef, Colonia and Steffen). The radar system is comprised by a hanging bow-tie dipole antenna working at a central frequency of 20 MHz. The antenna is an aluminum structure of 7 x 5 x 1.2 m weighting near 350 kg that is hanging at 20 m below a helicopter, and is connected to the helicopter cabin by an optical fiber cable. At the antenna are installed a 3,200 Volts peak transmitter, a two channel radar receiver, and an integrated GPS registering each trace. The helicopter flying speed was kept at near 40 knots and the antenna was normally hanging at 40 m above the ice. The surveys took place along predefined tracks

  15. Mecanismos de tribalización en la patagonia: desde la gran crisis al primer gobierno peronista.

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    Walter Delrio

    2005-12-01

    Full Text Available En 1937 el gobierno argentino decide desalojar y trasladar a la tribu Nahuelpán bajo acusaciones de extranjería e in-civilización. Luego de seis años, la medida es revisada y se inicia un proceso de restitución parcial de las tierras involucradas seleccionándose desde el estado a quienes se continuaría reconociendo como "tribu" Nahuelpán. A partir de este caso enmarcado en el contexto de las relaciones establecidas por las comunidades indígenas del territorio nacional de Chubut con las autoridades nacionales y las redes locales de poder, se propone un análisis del proceso de construcción del espacio social para los pueblos originarios en la matriz estado-nación-territorio en el período que va de la gran crisis del '30 al primer gobierno peronista. Se abordan en particular los mecanismos de tribalización en la interfase entre políticas oficiales y agencia aborigen.In 1937, the Argentine government decided to displace and remove the Nahuelpán tribe accused of foreign and uncivilized behavior. Six years later this measure was reviewed starting a process of partial land restitution in which the state selected who will continue to be considered as member of the above mentioned tribe. Focusing in that case, framed by the relationship established between indigenous communities of the national territory of Chubut and state authorities or local nets of power, this article analyzes the process leading to the construction of a social space in the state-nation-territory matrix since the 1930' great crisis until the first period of President Juan Perón.

  16. El cariotipo fundamental de Alstroemeria patagonica (Alstroemeriaceae The fundamental karyotype of Alstroemeria patagonia (Alstroemeriaceae

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    Carlos M Baeza

    2011-12-01

    Full Text Available Se describe el cariotipo de Alstroemeria patagonica Phil. a partir de material de Chile. Esta especie presenta un cariotipo 2n = 2x = 16, y una fórmula haploide de 1m + 2sm + 1sm-sat + 2st + 1st-sat + 1t. El cariotipo encontrado es muy asimétrico (AsK % = 76,0.The karyotype of Alstroemeria patagonia Phil. from Chile was described. The species had a karyotype 2n = 2x = 16, and the haploid formula was 1m + 2sm + 1sm-sat + 2st + 1st-sat + 1t. The reported karyotype was very asymmetric (AsK % = 76.0.

  17. Lack of founding Amerindian mitochondrial DNA lineages in extinct aborigines from Tierra del Fuego-Patagonia.

    Science.gov (United States)

    Lalueza, C; Pérez-Pérez, A; Prats, E; Cornudella, L; Turbón, D

    1997-01-01

    Ancient DNA from bones and teeth of 60 individuals from four extinct human populations from Tierra del Fuego-Patagonia (Selknam, Yamana, Kaweskar and Aonikenk) has been extracted and the mitochondrial DNA (mtDNA) amplified by using the polymerase chain reaction. High-resolution analysis of endonuclease restriction site variation in the mtDNA and sequencing of its hypervariable non-coding control region, revealed complete absence of two of the four primary mitochondrial haplotype groups present in contemporary Amerinds, namely A and B. In contrast, haplogroups C and D were found in all but one sample with frequencies of approximately 38% and 60%. These results, together with the decreasing incidence of group A in more southerly latitudes in the American continent and the absence of cluster B above 55 degrees North in America and Asia, argue that the first settlers entering America 21000-14000 years ago already lacked both mtDNA lineages.

  18. Alien invasions and the game of hide and seek in Patagonia.

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    Martin Lindegren

    Full Text Available The introduction, establishment and spread of alien species is a major threat to biodiversity and the provision of ecosystem services for human wellbeing. In order to reduce further loss of biodiversity and maintain productive and sustainable ecosystems, understanding the ecological mechanisms underlying species invasions and avoiding potentially harmful effects on native communities is urgently needed, but largely lacking. We here demonstrate, by means of hydroacoustics and advanced spatial modelling, how native fish species as a result of previous exposure to native predators may successfully respond to invasive novel predators through a complicated game of hide and seek, minimizing spatio-temporal overlap with predators, and potentially facilitating coexistence between native prey species (Galaxiids and introduced novel predators (Salmonids in a deep Andean lake, Patagonia.

  19. A gigantic, exceptionally complete titanosaurian sauropod dinosaur from southern Patagonia, Argentina.

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    Lacovara, Kenneth J; Lamanna, Matthew C; Ibiricu, Lucio M; Poole, Jason C; Schroeter, Elena R; Ullmann, Paul V; Voegele, Kristyn K; Boles, Zachary M; Carter, Aja M; Fowler, Emma K; Egerton, Victoria M; Moyer, Alison E; Coughenour, Christopher L; Schein, Jason P; Harris, Jerald D; Martínez, Rubén D; Novas, Fernando E

    2014-09-04

    Titanosaurian sauropod dinosaurs were the most diverse and abundant large-bodied herbivores in the southern continents during the final 30 million years of the Mesozoic Era. Several titanosaur species are regarded as the most massive land-living animals yet discovered; nevertheless, nearly all of these giant titanosaurs are known only from very incomplete fossils, hindering a detailed understanding of their anatomy. Here we describe a new and gigantic titanosaur, Dreadnoughtus schrani, from Upper Cretaceous sediments in southern Patagonia, Argentina. Represented by approximately 70% of the postcranial skeleton, plus craniodental remains, Dreadnoughtus is the most complete giant titanosaur yet discovered, and provides new insight into the morphology and evolutionary history of these colossal animals. Furthermore, despite its estimated mass of about 59.3 metric tons, the bone histology of the Dreadnoughtus type specimen reveals that this individual was still growing at the time of death.

  20. Ethical and Civic Education. Difficulties during the Curricular Reform in Argentine Patagonia

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    Isabelino Siede

    2015-04-01

    Full Text Available DOI: http://dx.doi.org/10.17227/01234870.41folios51.68 What type of ethical and civic education is effectively provided at school? This article analyzes the curricular prescriptions of Ethical and Citizenship Education in primary schools of the Argentine Patagonia, as well as its relations and contradictions with the school practices of moral education It inquires the process of definition of the area in the context of the Educational Reform in the 90s. Also, it pursuits to remake the way it was incorporated in the provincial curriculum design. Throughout focus groups and interviews to teachers from different public and private schools of three towns from de north of Santa Cruz, we analyze the descriptions and expectative of the teachers about their teaching practice in the moral area, as well as the possible causes of the differences and the contradictions between the policies of the curricular statement and educational proposals offered at school.

  1. Preliminary K/Ar geochronology of the Crater Basalt volcanic field (CBVF, northern Patagonia

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    Z. Pécskay

    2007-03-01

    Full Text Available The Crater Basalt volcanic field is one of the Quaternary intraplate basaltic fields in northern Patagonia. A systematic geological, volcanological and geochronological study of CBVF indicates a multistage history of eruptions of basaltic volcanoes. K/Ar dating, using whole rock samples shows that the measured analytical ages are fully consistent with the available stratigraphic control. The radiometric ages fall into three distinct, internally consistent age groups, which give evidence that there were at least three major episodes of volcanic activity, at about 1.0 Ma, 0.6 Ma and 0.3 Ma ago. The age differences appear to be just significant, even although less than 10 % radiogenic argon was found in the isotope analysis of whole rock samples.

  2. First paleoparasitological record of acanthocephalan eggs from Northwestern Patagonia (Late Holocene, Argentina).

    Science.gov (United States)

    Beltrame, María Ornela; Fernández, Fernando Julián; Sardella, Norma Haydeé

    2015-06-01

    Eggs representative of an acanthocephalan were found in an ancient fragment of raptor pellet, probably belonged to the barn owl, Tyto alba, from the archeological site named "Epullán Chica cave." This site is a cave located at the southern of Neuquén Province, Patagonia, Argentina. The fragment of pellet was found in a layer with charcoals dated at 1980±80 years B.P. A total of 56 eggs were found. Eggs were brown colored and thick-shelled, and presented four membranes, the outer lightly sculpted. The embryos presented hooks in one extremity. Measurements ranged from 87.5 to 107.5μm long and 50 to 57.5μm wide. Eggs were very well-preserved, and were identified as belonged to Class Archiacanthocephala, Order Oligacanthorhynchida, Family Oligacanthorhynchidae, probably Macracanthorhynchus Travassos, 1917, or an unidentified species. This is the first report of small mammal acanthocephalans from ancient material worldwide.

  3. Insectos acuáticos de la Meseta del Somuncura, Patagonia, Argentina. Inventario preliminar

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    Javier MUZÓN

    2005-01-01

    Full Text Available Se brinda un inventario preliminar de los insectos acuáticos de la Meseta del Somuncura y su área de influencia (Patagonia, Argentina realizado sobre la base de colecciones y registros previos de especies pertenecientes a los órdenes Ephemeroptera, Odonata, Hemiptera (Heteroptera, Trichoptera, Diptera (familias Ceratopogonidae, Culicidae y Psychodidae y Coleoptera. Se han relevado diversos tipos de ambientes en 14 localidades. El número de especies registrado asciende a 78, agrupadas en 51 géneros y 26 familias, de las cuales 33 se citan por primera vez del área. De los taxa registrados 83% de los géneros corresponden a grupos de amplia distribución (neotropicales, americanos o cosmopolitas, mientras que 41% de las especies presentan una distribución patagónica o andina.

  4. Estado del conocimiento taxonómico de la fauna de Chironomidae (Diptera: Nematocera de la Patagonia Current state of the taxonomic knowledge of the Chironomidae fauna (Diptera: Nematocera from Patagonia

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    Mariano Donato

    2009-06-01

    Full Text Available La familia Chironomidae (Diptera: Nematocera es uno de los grupos de insectos más ampliamente distribuidos y abundantes en cuerpos de agua dulce. Los representantes de esta familia pueden explotar áreas con amplios gradientes ambientales. La información que se presenta está basada en la recopilación de datos distribucionales bibliográficos, del estudio del material tipo de las especies de Chironomidae depositadas en el Natural History Museum (UK y del material de colección del Museo de La Plata (Argentina. En la Patagonia, se registran 9 subfamilias, la subfamilia monotípica Chilenomyiinae es endémica de esta área. Dentro de estas subfamilias, 53 de los 111 géneros conocidos para América del Sur están presentes en la Patagonia. Del total de géneros de la Patagonia, el 20 % es endémico y 7 de ellos muestran relaciones transantárticas. En la Patagonia, se registran 177 especies de Chironomidae, el 98% de éstas son endémicas, el 3 % son consideradas nomina dubia y el 17% requiere revisión ya que su ubicación sistemática es dudosa. Las descripciones originales de las especies patagónicas de Chironomidae están basadas principalmente sobre machos (n=58 y machos y hembras (n=43, ambas representan el 57% del total; el resto de las especies han sido descriptas con diferentes combinaciones de estadios del ciclo de desarrollo.The Chironomidae (Diptera: Nematocera family is one of the most widely distributed group of insects and often the most abundant in freshwater environments. Representatives of this family can exploit a wide range of environmental gradients. The information here presented is based on the compilation of distributional data obtained from bibliography, the study of the type material deposited in the Natural History Museum (UK and the collection material from Museo de La Plata (Argentina. Nine subfamilies are recorded from Patagonia, being the monotypic subfamily Chilenomyiinae endemic for the area. From the 111 known

  5. Capacity building for freshwater insect studies in northern Patagonia, Argentina: DARWIN Initiative programme

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    Stephen J. BROOKS

    2009-01-01

    Full Text Available Este proyecto fue financiado durante un período de tres años, desde septiembre de 2006 a través de la Iniciativa Darwin del gobierno Británico. El objetivo de este trabajo es el estudio de los insectos acuáticos del Parque Nacional Nahuel Huapi (PNNHP, Patagonia, Argentina. El parque incluye una gran variedad de hábitats que comprenden arroyos, ríos y lagos los cuales se distribuyen desde el bosque siempreverde frío, hasta la zona árida de estepa. Todo el material será identificado y depositado en las colecciones del Museo La Plata y el Museo de Historia Natural de Londres. Los fondos de la Iniciativa Darwin han sido utilizados para equipar un laboratorio de biodiversidad en las oficinas del PNNHP en Bariloche y la estación de investigación en Puerto Blest. Toda la información de los insectos acuáticos y las distintas formaciones vegetales donde éstos se han encontrado, se incluirá en una base de datos (la primera de su tipo en Patagonia que utilizará la metodología GIS para analizar patrones de distribución de las especies en el parque. En estos momentos se están produciendo varias guías de campo para identificar los insectos acuáticos del PNNHP. Es nuestro deseo que los resultados obtenidos en este proyecto, contribuyan a la conservación de los sistemas acuáticos en Argentina y América del Sur

  6. Preliminary K/Ar geochronology of the Crater Basalt volcanic field (CBVF, northern Patagonia

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    Z. Pécskay

    2007-11-01

    Full Text Available The Crater Basalt volcanic field is one of the Quaternary intraplate basaltic fields in northern Patagonia. A systematic geological, volcanological and geochronological study of CBVF indicates a multistage history of eruptions of basaltic volcanoes. K/Ar dating, using whole rock samples shows that the measured analytical ages are fully consistent with the available stratigraphic control. The radiometric ages fall into three distinct, internally consistent age groups, which give evidence that there were at least three major episodes of volcanic activity, at about 1.0 Ma, 0.6 Ma and 0.3 Ma ago. The age differences appear to be just significant, even although less than 10 % radiogenic argon was found in the isotope analysis of whole rock samples.El campo volcánico del Basalto Cráter (CVBC constituye uno de los campos basálticos cuaternarios de intraplaca de la Patagonia septentrional. El estudio sistemático de la geología, volcanología y geocronología del CVBC muestra una historia eruptiva multiepisódica de volcanes basálticos. Las dataciones K-Ar realizadas sobre roca total son coherentes con el control estratigráfico. Las edades obtenidas para el Basalto Cráter permiten distinguir tres episodios diferentes, pero individualmente coherentes, de actividad volcánica, ocurridos hace ~1,0 Ma; 0,6 Ma y 0,3 Ma. Las diferencias de edad parecen ser significativas, aún cuando el contenido de argón radiogénico determinado en los análisis de roca total resultó menor al 10 %.

  7. Cultural Transmission of Traditional Knowledge in two populations of North-western Patagonia

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    Lozada Mariana

    2008-12-01

    Full Text Available Abstract Background In the present study we have investigated the cultural transmission of two types of traditional plant knowledge in two communities of North-western Patagonia, Argentina. In the Pilcaniyeu community, we studied the transmission of traditional knowledge related to horticultural practices in home-gardens, greenhouses and gardens; while in the community of Cuyin Manzano, we studied wild plant gathering customs. Methods Ethnobotanical fieldwork was conducted by means of semi-structured interviews, in which we investigated which plants are used, at what life history phase was learned, modes of transmission and who the principal transmitters were in childhood and adulthood. In both communities, each of this three aspects related to cultural transmission were categorized and the frequencies of each category were obtained. The total number of species recorded in each community was also calculated. Frequencies were analyzed with the Chi-square test of independence. Results and discussion In both communities, transmission of traditional plant knowledge begins at an early age, as a family custom, in which women play a predominant role. Wild plant use and horticultural knowledge continue to be learned during adulthood. This was particularly registered associated with horticultural learning, which receives greater influence from extension agents who are introducing new practices and technology. This outside influence, which implies novelty, could imply syncretism but also traditional knowledge loss. Conclusion Given the remarkable acculturation processes occurring at present in rural communities of Northwestern Patagonia, it might be of vital importance to document traditional knowledge of ancient practices. Moreover, it could be interesting to share our results with both populations in order to encourage participatory activities within the communities which could enhance traditional knowledge horizontal transmission, particularly among

  8. Respiratory Function in Voluntary Participating Patagonia Sea Lions (Otaria flavescens) in Sternal Recumbency.

    Science.gov (United States)

    Fahlman, Andreas; Madigan, Johnny

    2016-01-01

    We measured esophageal pressures (n = 4), respiratory flow rates (n = 5), and expired O2 and CO2 (n = 4) in five adult Patagonia sea lions (Otaria flavescens, body mass range 94.3-286.0 kg) during voluntary breaths while laying down out of water. The data were used to estimate the dynamic specific lung compliance (sCL), the O2 consumption rate ([Formula: see text]O2) and CO2 production rates ([Formula: see text]CO2) during rest. Our results indicate that the resting tidal volume in Patagonia sea lions is approximately 47-73% of the estimated total lung capacity. The esophageal pressures indicated that expiration is passive during voluntary breaths. The average sCL of sea lions was 0.41 ± 0.11 cmH2O(-1), which is similar to those measured in anesthetized sea lions and awake cetaceans, and significantly higher as compared to humans (0.08 cmH2O(-1)). The average estimated [Formula: see text]O2 and [Formula: see text]CO2 using breath-by-breath respirometry were 1.023 ± 0.327 L O2 min(-1) (range: 0.695-1.514 L O2 min(-1)) and 0.777 ± 0.318 L CO2 min(-1), (range: 0.510-1.235 L CO2 min(-1)), respectively, which is similar to previously published metabolic measurements from California and Steller sea lions using conventional flow-through respirometry. Our data provide end-tidal gas composition and offer novel data for respiratory physiology in pinnipeds, which may be important for clinical medicine and conservation efforts.

  9. Respiratory function in voluntary participating Patagonia sea lions in sternal recumbency

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    Andreas Fahlman

    2016-11-01

    Full Text Available We measured esophageal pressures (n=4, respiratory flow rates (n=5, and expired O2 and CO2 (n=4 in five adult Patagonia sea lions (Otaria flavescens, body mass range 94.3-286.0 kg during voluntary breaths while laying down. The data were used to estimate the dynamic specific lung compliance (sCL, cmH2O-1, the O2 consumption rate (VO2 and CO2 production rates (VCO2 during rest. Our results indicate that the resting tidal volume in Patagonia sea lions is approximately 47-73% of the estimated total lung capacity. The esophageal pressures indicated that expiration is passive during voluntary breaths. The average sCL of dolphins was 0.41±0.11 cmH2O−1, which is similar to those measured in anesthetized sea lions and awake cetaceans, and significantly higher as compared with humans (0.08 cmH2O−1. The average estimated and using breath-by-breath respirometry were 1.023 ± 0.327 L O2 min-1 (range: 0.695-1.514 L O2 min−1 and 0.777 ± 0.318 L CO2 min-1, (range: 0.510-1.235 L CO2 min-1, respectively, which is similar to previously published metabolic measurements from California and Steller sea lions using conventional flow-through respirometry. Our data provide end-tidal gas composition and provide novel data for respiratory physiology in pinnpeds, which may be important for clinical medicine and conservation efforts.

  10. Stable oxygen isotopes (delta18(O)) in Austrocedrus chilensis tree rings reflect climate variability in northwestern Patagonia, Argentina.

    Science.gov (United States)

    Roig, F A; Siegwolf, R; Boninsegna, J A

    2006-11-01

    The stable oxygen isotope (delta (18)O) composition of Austrocedrus chilensis (D. Don) Endl. (Cupressaceae) tree rings potentially provide retrospective views of changes in environment and climate in the semi-arid lands of Patagonia. We report the development of the first annually resolved delta (18)O tree-ring chronology obtained from natural forests of the foothills of the northwestern Patagonian Andes. The isotope record spans between 1890 and 1994 AD. We explore the probable links between this record and the climate of the region. Air temperatures during summer conditions are significantly, but not strongly, inversely correlated with annual delta (18)O values from Austrocedrus tree rings. The strongest correlations are between the southern oscillation index (SOI) and the tree rings. The existence of millennial-age Austrocedrus trees in northern Patagonia provides interesting possibilities for examining these climate-related isotopic signals over most of the last 1,000 years.

  11. Detection of Salmonella enterica in Magellanic penguins (Spheniscus magellanicus) of Chilean Patagonia: evidences of inter-species transmission.

    Science.gov (United States)

    Dougnac, C; Pardo, C; Meza, K; Arredondo, C; Blank, O; Abalos, P; Vidal, R; Fernandez, A; Fredes, F; Retamal, P

    2015-04-01

    Patagonia in southern South America is among the few world regions where direct human impact is still limited but progressively increasing, mainly represented by tourism, farming, fishing and mining activities. The sanitary condition of Patagonian wildlife is unknown, in spite of being critical for the assessment of anthropogenic effects there. The aim of this study was the characterization of Salmonella enterica strains isolated from wild colonies of Magellanic penguins (Spheniscus magellanicus) located in Magdalena Island and Otway Sound, in Chilean Patagonia. Eight isolates of Salmonella were found, belonging to Agona and Enteritidis serotypes, with an infection rate of 0·38%. Resistance to ampicillin, cefotaxime, ceftiofur and tetracycline antimicrobials were detected, and some of these strains showed genotypic similarity with Salmonella strains isolated from humans and gulls, suggesting inter-species transmission cycles and strengthening the role of penguins as sanitary sentinels in the Patagonian ecosystem.

  12. Tree health influences diameter growth along site quality, crown class and age gradients in Nothofagus forests of southern Patagonia

    OpenAIRE

    2015-01-01

    We examined the influence of tree health on annual diameter increment of trees along gradients in stand site quality, crown classes and tree age in Nothofagus pumilio forests of Southern Patagonia. Healthy trees had higher annual diameter increment than unhealthy trees along all gradients (site quality, crown class, tree age). We argue that tree health could be employed as a qualitative variable in models of tree growth to estimate aboveground biomass and carbon stocks in this forest system. ...

  13. LA PATAGONIA ORIENTAL SEGÚN UNA REAL CÉDULA de 1570 MENOSPRECIADA POR LA HISTORIOGRAFÍA CHILENA

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    MANUEL RAVEST MORA

    2005-12-01

    Full Text Available Versa este trabajo sobre la Real Cédula de Felipe II que, en 1570, fusionó parte de la Patagonia Oriental con la Provincia del Río de la Plata, origen de la República Argentina, donde, al parecer, supieron del documento treinta años después de finalizado el debate con Chile acerca de los derechos al extremo meridional de América. Descubierta por un diplomático chileno, que informó de ella a su Cancillería en 1876 y la mencionó en un libro publicado en 1903, ha sido sistemáticamente ignorada por los escritores chilenos. Examina este trabajo las posibles causas de ese silencio historiográfico, como también las rectificaciones que la RC introduce en la tesis clásica o fundacional de Chile, formulada a mediados del XIX por Miguel Luis Amunátegui, según la cual ese país siempre ejerció jurisdicción sobre la totalidad de la Patagonia Oriental desde 1554This work deals with a 1570 Phillip the II Decree that fused a section of Atlantic Patagonia with the Rio de la Plata Province, origin of late Argentine Republic, who, apparently, learned about it thirty years after ended the discussion held with Chile in respect the rights of each country towards the southern extreme of America. Found by a chilean diplomat, who informed his Ministry of Foreign Affairs in 1876 and wrote about the document in a book published in 1903, it has been systematically ignored by chilean scholars. The work examines the possible causes for this historiographyc silence, and the rectifications that the Royal Decree introduces in the classical chilean thesis about Patagonia, enounced by Miguel Luis Amunategui in middle XIX century, according to which that whole territory always belonged to Chile since 1554

  14. Estado del conocimiento taxonómico de la fauna de Chironomidae (Diptera: Nematocera de la Patagonia

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    Mariano DONATO

    2009-01-01

    Full Text Available La familia Chironomidae (Diptera: Nematocera es uno de los grupos de insectos más ampliamente distribuidos y abundantes en cuerpos de agua dulce. Los representantes de esta familia pueden explotar áreas con amplios gradientes ambientales. La información que se presenta está basada en la recopilación de datos distribucionales bibliográficos, del estudio del material tipo de las especies de Chironomidae depositadas en el Natural History Museum (UK y del material de colección del Museo de La Plata (Argentina. En la Patagonia, se registran 9 subfamilias, la subfamilia monotípica Chilenomyiinae es endémica de esta área. Dentro de estas subfamilias, 53 de los 111 géneros conocidos para América del Sur están presentes en la Patagonia. Del total de géneros de la Patagonia, el 20 % es endémico y 7 de ellos muestran relaciones transantárticas. En la Patagonia, se registran 177 especies de Chironomidae, el 98% de éstas son endémicas, el 3 % son consideradas nomina dubia y el 17% requiere revisión ya que su ubicación sistemática es dudosa. Las descripciones originales de las especies patagónicas de Chironomidae están basadas principalmente sobre machos (n=58 y machos y hembras (n=43, ambas representan el 57% del total; el resto de las especies han sido descriptas con diferentes combinaciones de estadios del ciclo de desarrollo.

  15. Biodiversidad de Heteroptera (Hemiptera acuáticas y semiacuáticas de la Patagonia argentina

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    María Cecilia MELO

    2009-01-01

    Full Text Available Las Heteroptera acuáticas y semiacuáticas (infraórdenes Nepomorpha, Gerromorpha y Leptopodomorpha no presentan una alta diversidad específica en Argentina, hasta el momento se han registrado 208 especies. Carlos Berg en 1881, publica el primer trabajo que hace referencia a heterópteros de la Patagonia, en el que lista los insectos recolectados durante la Campaña del Desierto. Desde principios de la década del ’60, las Heteroptera acuáticas han sido estudiadas principalmente por A.O. Bachmann y colaboradores. Hasta el momento, se han registrado 36 especies pertenecientes a las familias Corixidae, Notonectidae, Belostomatidae, Gelastocoridae, Naucoridae y Nepidae (Nepomorpha; Hydrometridae, Veliidae y Mesoveliidae (Gerromorpha, y Saldidae (Leptopodomorpha. La mayoría de estas especies extienden su distribución geográfica hacia el norte de la Argentina, excepto Sigara (Tropocorixa egbertae Hungerford, S. (T. trimaculata (Le Guillou, S. (T. vuriloche Bachmann, S. (T. forciceps (Spinola, Trichocorixa milicorum Bachmann (Corixidae, Notonecta (Paranecta virescens Blanchard, N. (P. fazi Hungerford, N. (P. vereertbruggheni Hungerford (Notonectidae, Pseudosaldula bergi (Haglund y P. paralia (Torres, P. angusta (Drake & Carvalho, P. sola (Drake & Carvalho, P. doeringi (Drake & Carvalho y Saldula differata Drake & Carvalho (Saldidae, que son exclusivas de la Patagonia. El conocimiento de la diversidad de Heteroptera acuáticas y semiacuáticas en la Patagonia es bueno y, por los datos recogidos, su estado de conservación es aceptable ya que aproximadamente el 40% de la especies encontradas en áreas naturales protegidas son exclusivas de la región y representan cerca del 40 % del número de especies exclusivas de la Patagonia.

  16. Modern and subrecent spatial distribution and characteristics of sediment infill controlled by internal depositional dynamics, Laguna Potrok Aike (southern Patagonia, Argentina)

    Science.gov (United States)

    Kastner, S.; Ohlendorf, C.; Haberzettl, T.; Lücke, A.; Maidana, N. I.; Mayr, C.; Schäbitz, F.; Zolitschka, B.

    2009-04-01

    Situated in the dry steppe environment of south-eastern Patagonia the 100 m deep and max. 770 ka old maar lake Laguna Potrok Aike (51°58'S, 70°23'W) has a high potential as a palaeolimnological key site for the reconstruction of terrestrial palaeoclimate conditions. As this area is sensitive to variations in southern hemispheric wind and pressure systems the lake holds a unique lacustrine record of palaeoclimatic and palaeoecological variability. Depositional changes inferred from the lacustrine sediment sequence as well as subaerial and subaquatic lake level terraces provide detailed information about the water budget of the lake related to the variability of the Southern Hemispheric Westerlies. For this reason the lake was chosen as an ICDP drilling site in 2008 within the "Potrok Aike maar lake sediment archive drilling project" (PASADO). Based on high resolution multi-proxy investigations of the last 16,000 years carried out on a 18.9 m long sediment record (Haberzettl et al., 2007; Mayr et al., 2009; Wille et al., 2007) this study focuses on the understanding of internal depositional dynamics which control the characteristics and spatial distribution of the sediment infill of this lake. Furthermore, it provides information improving the accuracy of the interpretation of the long sediment record recovered within the PASADO project. A survey of the spatial sediment distribution was carried out in 2005 using 46 gravity cores of up to 49 cm length covering a range of water depths from 9 to 100 m. All 46 cores were scanned with X-ray fluorescence technique and for magnetic susceptibility with up to 1 mm spatial resolution. Using Ca and Ti as well as magnetic susceptibility data the cores were correlated and linked to the established age model (Haberzettl et al., 2005). As these parameters vary considerably and not consistently within the suite of littoral cores, a correlation prior to the 2005 sediment surface is solely based on cores from water depths exceeding

  17. La materia orgánica particulada: comparación de métodos para su determinación y su valor como indicador de calidad de suelos del Chubut Particulate organic-matter: a comparison of methods for its determination and its role as an indicator of soil quality for some soils in the province of Chubut

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    Lina Sonia Videla

    2008-12-01

    Full Text Available La materia orgánica particulada (MOP es un componente dinámico del suelo, que responde selectiva y rápidamente a los cambios de manejo y distintos tipos de disturbios. El objetivo de este estudio fue comparar dos técnicas de determinación de MOP en distintos suelos y evaluar el potencial de esta variable como indicadora de calidad de los mismos. Se estudiaron tres sitios ecológicos de la provincia del Chubut con distinto manejo o afectados por distintos disturbios: Media Luna Clausura (ML C, Media Luna Pastoreo (ML P, Puerto Madryn bioperturbado (PM B, Puerto Madryn no bioperturbado (PM NB, Punta Ninfas no erosionado (PN NE y Punta Ninfas erosionado (PN E. En muestras de suelos extraídas de 0 a 5 cm (PM y PN y de 0 a 10 cm (ML de profundidad se determinó la materia orgánica total (MOT y la MOP por vía húmeda (MOPh (Método Walkley y Black y por ignición en mufla (MOPi a 430 °C. En los Molisoles de ML y en los Aridisoles de PM la MOPi fue mayor que la MOPh, mientras que para los Aridisoles de PN no se registraron diferencias significativas entre los dos métodos. Para los suelos con carbonatos (PM o con alofanos (ML, el método por ignición sobreestimó los contenidos de MOP. La MOT presentó una alta correlación con la MOPh y con la MOPi para todos los suelos en conjunto (r² = 0,89 y r² = 0,73, respectivamente. El suelo que presentó una mayor relación MOP/MOT fue PN NE. En contraste, el suelo PN E, mostró los valores más bajos para esta relación, lo que indicaría, por un lado, que la poca MO que contienen estos suelos está predominantemente asociada a la fracciónParticulate organic-matter (MOP is a dynamic soil component that quickly and selectively responds to management changes and to different disturbance regimes. We compared two techniques to determine the MOP content in different soils and assessed the potential of this variable as an indicator of soil quality. We studied the soils of three ecological sites located

  18. The Usefulness of Edible and Medicinal Fabaceae in Argentine and Chilean Patagonia: Environmental Availability and Other Sources of Supply

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    Soledad Molares

    2012-01-01

    Full Text Available Fabaceae is of great ethnobotanical importance in indigenous and urban communities throughout the world. This work presents a revision of the use of Fabaceae as a food and/or medicinal resource in Argentine-Chilean Patagonia. It is based on a bibliographical analysis of 27 ethnobotanical sources and catalogues of regional flora. Approximately 234 wild species grow in Patagonia, mainly (60% in arid environments, whilst the remainder belong to Sub-Antarctic forest. It was found that 12.8% (30 species, mainly woody, conspicuous plants, are collected for food or medicines. Most of the species used grow in arid environments. Cultivation and purchase/barter enrich the Fabaceae offer, bringing it up to a total of 63 species. The richness of native and exotic species, and the existence of multiple strategies for obtaining these plants, indicates hybridization of knowledge and practices. Only 22% of the total species used are mentioned in bothcontexts of food and medicine, reflecting low-use complementation. This study suggests a significant ecological appearance and a high level of availability in shops and exchange networks in Patagonia, highlighting the need to consider the full set of environmental and socioeconomic factors in research related to the use and cultural importance of plants in regional contexts.

  19. First paleoparasitological record of digenean eggs from a native deer from Patagonia Argentina (Cueva Parque Diana archaeological site).

    Science.gov (United States)

    María Ornela, Beltrame; Eleonor, Tietze; Alberto Enrique, Pérez; Norma Haydeé, Sardella

    2017-02-15

    Eggs representative of a digenean species were found in coprolites belonged to an endemic deer from Patagonia. Samples were collected from the archaeological site named "Cueva Parque Diana". This site is a cave located at the Lanín National Park, Neuquén Province, Argentina. The coprolites were dated from 2370±70 to 580±60 years B.P. The eggs were ellipsoidal, operculated, yellowish and thin-shelled. Measurements (n=65) ranged from 120.0 to 142.5 (133.2±6.53) μm long and 62.5 to 87.5 (72.6±6.15) μm wide. Eggs were well-preserved and were identified as belonged to Class Trematoda, Subclass Digenea, similar to those of Fasciola hepatica or with another species not identified at present from Patagonia. This is the first report of digenean eggs from ancient deer worldwide. The present study confirms the presence of representatives of digenean species in endemic deer from Patagonia in ancient times and the presence of a trematode disease prior to the arrival of European cattle.

  20. Do native grazers from Patagonia, Argentina, consume the invasive kelp Undaria pinnatifida? ¿Pueden los pastoreadores nativos de Patagonia, Argentina, consumir al alga invasora Undaria pinnatifida?

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    S. Valeria Teso

    2009-06-01

    Full Text Available The invasive kelp Undaria pinnatifida (Phaeophyceae, Laminariales was first reported in Golfo Nuevo in 1992 and since then it has spread widely over more than 170 km, all along the northern Patagonian coast, Argentina. Field observations in the region have indicated the potential role of invertebrate grazers, like the sea urchins Arbacia dufresnii and Pseudechinus magellanicus and the gastropod Tegula patagonica, in controlling algal density. Laboratory experiments were conducted to ascertain whether, and if so, to what extent these grazers actually feed on the algae. The studied sea urchins fed on the alga, whereas the snail scraped off biofouling adhered to its surface. Higher densities of grazers were observed on the kelp during summer and might be attributed to increasing in metabolism with increasing temperature, and degradation of blades and sporophylls, which possibly increase their palatability.El alga invasora Undaria pinnatifida (Phaeophyceae, Laminariales fue reportada por primera vez en Golfo Nuevo en 1992, dispersándose ampliamente a lo largo de 170 km de costa en el norte de la Patagonia, Argentina. Observaciones de campo hechas en los erizos de mar Arbacia dufresnii y Pseudechinus magellanicus y en el gasterópodo Tegula patagonica evidenciaron que son posibles consumidores de Undaria pinnatifida en la población local. Se realizaron experimentos de laboratorio con el objetivo de probar si estos pastoreadores eran capaces de consumir el alga. Los erizos de mar estudiados consumen el alga, mientras que el gasterópodo ramonea los epibiontes presentes sobre su superficie. Altas densidades de ramoneadores fueron encontradas sobre el alga durante el verano y podrían ser atribuidas a un aumento del su metabolismo con el aumento de la temperatura y a la degradación de las láminas y esporofilos, lo cual posiblemente aumente la palatabilidad del alga.

  1. Noble gas composition of subcontinental lithospheric mantle: An extensively degassed reservoir beneath Southern Patagonia

    Science.gov (United States)

    Jalowitzki, Tiago; Sumino, Hirochika; Conceição, Rommulo V.; Orihashi, Yuji; Nagao, Keisuke; Bertotto, Gustavo W.; Balbinot, Eduardo; Schilling, Manuel E.; Gervasoni, Fernanda

    2016-09-01

    Patagonia, in the Southern Andes, is one of the few locations where interactions between the oceanic and continental lithosphere can be studied due to subduction of an active spreading ridge beneath the continent. In order to characterize the noble gas composition of Patagonian subcontinental lithospheric mantle (SCLM), we present the first noble gas data alongside new lithophile (Sr-Nd-Pb) isotopic data for mantle xenoliths from Pali-Aike Volcanic Field and Gobernador Gregores, Southern Patagonia. Based on noble gas isotopic compositions, Pali-Aike mantle xenoliths represent intrinsic SCLM with higher (U + Th + K)/(3He, 22Ne, 36Ar) ratios than the mid-ocean ridge basalt (MORB) source. This reservoir shows slightly radiogenic helium (3He/4He = 6.84-6.90 RA), coupled with a strongly nucleogenic neon signature (mantle source 21Ne/22Ne = 0.085-0.094). The 40Ar/36Ar ratios vary from a near-atmospheric ratio of 510 up to 17700, with mantle source 40Ar/36Ar between 31100-6800+9400 and 54000-9600+14200. In addition, the 3He/22Ne ratios for the local SCLM endmember, at 12.03 ± 0.15 to 13.66 ± 0.37, are higher than depleted MORBs, at 3He/22Ne = 8.31-9.75. Although asthenospheric mantle upwelling through the Patagonian slab window would result in a MORB-like metasomatism after collision of the South Chile Ridge with the Chile trench ca. 14 Ma, this mantle reservoir could have remained unhomogenized after rapid passage and northward migration of the Chile Triple Junction. The mantle endmember xenon isotopic ratios of Pali-Aike mantle xenoliths, which is first defined for any SCLM-derived samples, show values indistinguishable from the MORB source (129Xe/132Xe =1.0833-0.0053+0.0216 and 136Xe/132Xe =0.3761-0.0034+0.0246). The noble gas component observed in Gobernador Gregores mantle xenoliths is characterized by isotopic compositions in the MORB range in terms of helium (3He/4He = 7.17-7.37 RA), but with slightly nucleogenic neon (mantle source 21Ne/22Ne = 0.065-0.079). We

  2. Late Holocene environmental changes in a mesotidal estuary from Patagonia, Argentina

    Science.gov (United States)

    Espinosa, Marcela; Escandell, Alejandra; Velez Agudelo, Camilo

    2016-04-01

    Two sediment records from the lower valley of Negro River, Patagonia, Argentina (41°01´S; 62°47'W) spanning for the last 2000 cal yrs BP were analyzed according to diatoms and sediments contents. The river originates at the junction of the Neuquén and the Limay Rivers, Northern Patagonia, and discharges more than 1000 m3/s to the South Atlantic Ocean. Mesotidal conditions dominate at the inlet (2.95 m) affecting the lower valley (about 20 km) where salinity decreases drastically in the last 2 km. Fossil diatom assemblages and grain size were studied from two cores located at 1.5 km (Villarino site) and 12 km (Criadero site) from the inlet. Samples for modern diatom analyses were collected from the littoral zone at eleven sites along the river. Physical and chemical variables were quantified representing the maximum heterogeneity along the aquatic environment. Turbidity, salinity, conductivity, pH and temperature data were obtained in situ during summer and winter. In addition, a surface sediment sample was taken for grain size analysis and organic matter content, and water samples were taken to analyze nutrients and major ions following standard methods. The diatom content of modern sediment samples were studied in order to achieve ecological information useful as modern analogous for Patagonian rivers. Diatom zones were characterized by constrained incremental sum of squares cluster analysis (single linkage, Euclidean distance) in the fossil sequences. Fossil and modern diatom assemblages were compared with Detrended Correspondence Analysis (DCA). A total of 77 samples (modern and fossils) were analyzed and more than 200 taxa were identified. Diatom assemblages showed distinct abundance patterns in relation to salinity with a shift from communities dominated by marine/brackish taxa in lower sites to communities dominated by freshwater taxa in the middle and upper course of the river. The record of Criadero core (12 km from the inlet) began 2000 cal yrs BP with

  3. The origin of pyroxene megacrysts in alkali basalts from Patagonia, Argentina

    Science.gov (United States)

    Ntaflos, Theo; Bjerg, Ernesto; Gregoire, Michel

    2015-04-01

    Clinopyroxene and othopyroxene megacrysts have been brought to the surface together with mantle xenoliths by Neogene and Quaternary alkali basalts from the back-arc environment in Patagonia. The collected megacrysts are from Pali Aike Volcanic Field (El Ruido, maar) and the Gobernador Gregores cinder cone in southern Patagonia, and from the Laguna Fria outcrop in northern Patagonia. The most frequent pyroxene megacrysts are augites (twelve samples), one diopside and two enstatites. Enstatites were found in El Ruido and Laguna Fria. The augites are magnesian rich with MG# that vary from 73.1 to 75.3 in Gobernador Gregores, fairly constant at 76.6 in El Ruido and from 74.0 to 78.6 in Laguna Fria. The MG# of diopside is 91.1 and the two enstatites, one from Gobernador Gregores and the other from Laguna Fria, have MG#s 78.3 and 82.5 respectively. The Na2O and TiO2 contents in augites vary from 0.99 to 2.06 wt% and from 0.69 to 1.86 wt% repectively. Systematically, the Gobernador Gregores augites have the highest TiO2 and Na2O contents. The primitive mantle normalized REE abundances have concave upwards patterns. While the Gobernador Gregores augites have (La/Y)N ratios that vary from 2.4 to 3.8, the El Ruido and Laguna Fria augites have ratios that vary from 0.91 to 1.74. The enstatites from both localities have similar MREE but they differ markedly in their LREE (in GG LaN=0.04xPM and in El Ruido LAN=0.14) and in their HREE (in Gobernador Gregores YbN=0.25 and in El Ruido YBN=0.6). The AL IV/AL VI in all augites is high and vary from 0.75 to1.07 suggesting that they have been formed at - more than 30 km depth. The calculated minimum equilibrium temperatures vary between 1260 to 1320°C. Pressure estimates for augites, with exception of the El Ruido augites with a pressure of 1.65 GP, vary between 1.27 and 1.47 GPa. Especially the pressure estimates from Gobernador Gregores megacrysts vary within a small interval from 1.29 to 1.36 GPa indicating an isobaric

  4. El caso del Outburst Flood histórico de la laguna Derrumbe, Cholila, Chubut: Colapso de dique Morénico en la Cordillera Norpatagónica

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    Bruno Colavitto

    2012-09-01

    Full Text Available La laguna Derrumbe es un cuerpo de agua ubicado en los Andes Norpatagónicos en la provincia de Chubut, Argentina. Está contenida en un circo glaciario y endicada por una morena frontal del glaciar homónimo. A través del reconocimiento de campo se pudo describir a esta laguna y a un importante depósito rocoso que se halla aguas abajo de la misma, interpretado como un depósito de outburst flood. Estos depósitos son generados por procesos de alta energía relacionados con la rotura de un dique natural, en este caso un dique morénico. El estudio realizado permitió concluir que la morena frontal del glaciar Derrumbe sufrió una rotura parcial en tiempos históricos, desatando así una inundación súbita aguas abajo de la laguna, a través del valle del río Tigre, en la localidad de Cholila. En este trabajo se analizaron las posibles causas que dieron lugar a la rotura, la cual probablemente sea producto del rápido retroceso que el glaciar experimentó durante la década del ´50 y principios del ´60. Retroceso comparable con el ocurrido en muchos de los cuerpos glaciares de los Andes Patagónicos durante el último siglo.

  5. Fire history in western Patagonia from paired tree-ring fire-scar and charcoal records

    Directory of Open Access Journals (Sweden)

    A. Holz

    2012-03-01

    Full Text Available Fire history reconstructions are typically based on tree ages and tree-ring fire scars or on charcoal in sedimentary records from lakes or bogs, but rarely on both. In this study of fire history in western Patagonia (47–48° S in southern South America (SSA we compared three sedimentary charcoal records collected in bogs with tree-ring fire-scar data collected at 13 nearby sample sites. We examined the temporal and spatial correspondence between the two fire proxies and also compared them to published charcoal records from distant sites in SSA, and with published proxy reconstructions of regional climate variability and large-scale climate modes. Two of our three charcoal records record fire activity for the last 4 ka yr and one for the last 11 ka yr. For the last ca. 400 yr, charcoal accumulation peaks tend to coincide with high fire activity in the tree-ring fire scar records, but the charcoal records failed to detect some of the fire activity recorded by tree rings. Potentially, this discrepancy reflects low-severity fires that burn in herbaceous and other fine fuels without depositing charcoal in the sedimentary record. Periods of high fire activity tended to be synchronous across sample areas, across proxy types, and with proxy records of regional climatic variability as well as major climate drivers. Fire activity throughout the Holocene in western Patagonia has responded to regional climate variation affecting a broad region of southern South America that is teleconnected to both tropical- and high-latitude climate drivers-El Niño-Southern Oscillation and the Southern Annular Mode. An early Holocene peak in fire activity pre-dates any known human presence in our study area, and consequently implicates lightning as the ignition source. In contrast, the increased fire activity during the 20th century, which was concomitantly recorded by charcoal from all the sampled bogs and at all fire-scar sample sites, is attributed to human-set fires

  6. Fire history in western Patagonia from paired tree-ring fire-scar and charcoal records

    Science.gov (United States)

    Holz, A.; Haberle, S.; Veblen, T. T.; de Pol-Holz, R.; Southon, J.

    2012-03-01

    Fire history reconstructions are typically based on tree ages and tree-ring fire scars or on charcoal in sedimentary records from lakes or bogs, but rarely on both. In this study of fire history in western Patagonia (47-48° S) in southern South America (SSA) we compared three sedimentary charcoal records collected in bogs with tree-ring fire-scar data collected at 13 nearby sample sites. We examined the temporal and spatial correspondence between the two fire proxies and also compared them to published charcoal records from distant sites in SSA, and with published proxy reconstructions of regional climate variability and large-scale climate modes. Two of our three charcoal records record fire activity for the last 4 ka yr and one for the last 11 ka yr. For the last ca. 400 yr, charcoal accumulation peaks tend to coincide with high fire activity in the tree-ring fire scar records, but the charcoal records failed to detect some of the fire activity recorded by tree rings. Potentially, this discrepancy reflects low-severity fires that burn in herbaceous and other fine fuels without depositing charcoal in the sedimentary record. Periods of high fire activity tended to be synchronous across sample areas, across proxy types, and with proxy records of regional climatic variability as well as major climate drivers. Fire activity throughout the Holocene in western Patagonia has responded to regional climate variation affecting a broad region of southern South America that is teleconnected to both tropical- and high-latitude climate drivers-El Niño-Southern Oscillation and the Southern Annular Mode. An early Holocene peak in fire activity pre-dates any known human presence in our study area, and consequently implicates lightning as the ignition source. In contrast, the increased fire activity during the 20th century, which was concomitantly recorded by charcoal from all the sampled bogs and at all fire-scar sample sites, is attributed to human-set fires and is outside the

  7. Neogene kinematic history of Nazca-Antarctic-Phoenix slab windows beneath Patagonia and the Antarctic Peninsula

    Science.gov (United States)

    Breitsprecher, Katrin; Thorkelson, Derek J.

    2009-01-01

    The Patagonian slab window is a subsurface tectonic feature resulting from subduction of the Nazca-Antarctic spreading-ridge system (Chile Rise) beneath southern South America. The geometry of the slab window had not been rigorously defined, in part because of the complex nature of the history of ridge subduction in the southeast Pacific region, which includes four interrelated spreading-ridge systems since 20 Ma: first, the Nazca-Phoenix ridge beneath South America, then simultaneous subduction of the Nazca-Antarctic and the northern Phoenix-Antarctic spreading-ridge systems beneath South America, and the southern Phoenix-Antarctic spreading-ridge system beneath Antarctica. Spreading-ridge paleo-geographies and rotation poles for all relevant plate pairs (Nazca, Phoenix, Antarctic, South America) are available from 20 Ma onward, and form the mathematical basis of our kinematic reconstruction of the geometry of the Patagonia and Antarctic slab windows through Neogene time. At approximately 18 Ma, the Nazca-Phoenix-Antarctic oceanic (ridge-ridge-ridge) triple junction enters the South American trench; we recognize this condition as an unstable quadruple junction. Heat flow at this junction and for some distance beneath the forearc would be considerably higher than is generally recognized in cases of ridge subduction. From 16 Ma onward, the geometry of the Patagonia slab window developed from the subduction of the trailing arms of the former oceanic triple junction. The majority of the slab window's areal extent and geometry is controlled by the highly oblique (near-parallel) subduction angle of the Nazca-Antarctic ridge system, and by the high contrast in relative convergence rates between these two plates relative to South America. The very slow convergence rate of the Antarctic slab is manifested by the shallow levels achieved by the slab edge (< 45 km); thus no point on the Antarctic slab is sufficiently deep to generate "normal" mantle-derived arc-type magmas

  8. History of views on the relative positions of Antarctica and South America: A 100-year tango between Patagonia and the Antarctic Peninsula

    Science.gov (United States)

    Miller, H.

    2007-01-01

    Discussion of continental drift around Antarctica began nearly 100 years ago. While the Gondwana connections of Antarctica to Africa and Australia have been well defined for decades, the relative pre-drift positions of the Antarctic Peninsula and Patagonia continue to be subjects of controversy. Certainly older figures, which showed a paleo-position of the Peninsula crossing over continental crust of the Falkland Plateau or even South Africa or Patagonia, are out of consideration now. But contradictory opinions remain over the relative paleo-position of the Peninsula as a more or less straight prolongation of the Patagonian Andes, versus a position parallel to Patagonia along the Pacific coast. Geological reasons are found for both opinions, but geophysical observations on the adjacent ocean floors, particularly the evolution of the Weddell Sea crust, speak for the last-mentioned reconstruction.

  9. OSTEOMETRÍA DE VICUGNA VICUGNA MOLINA, 1782 EN EL PLEISTOCENO FINAL DE PATAGONIA MERIDIONAL CHILENA: IMPLICANCIAS PALEOECOLÓGICAS Y BIOGEOGRÁFICAS / Osteometry of Vicugna vicugna Molina, 1782 in the late Pleistocene of southern chilean Patagonia

    Directory of Open Access Journals (Sweden)

    Rafael Labarca Encina

    2009-12-01

    Full Text Available  Se presenta un análisis osteométrico uni y multivariado con los materiales fósiles -principalmente huesos cortos y falanges- de Vicugna sp. del yacimiento Cueva Lago Sofía 4 (13500 – 11000 AP, ubicado en la provincia de Última Esperanza (Región de Magallanes, Chile. Los resultados indican que los elementos analizados poseen un tamaño compatible con los registrados para Vicugna vicugna, no superando en ningún caso a los especímenes conocidos para Vicugna gracilis del Pleistoceno de la región Pampeana. Esto confirma la información morfológica y de ADN antiguo que indicaba la presencia de Vicugna vicugna en la Patagonia meridional chilena. Se discuten los resultados en términos taxonómicos, biogeográficos y paleoecológicos sugiriendo que la presencia de este taxón fuera de su rango actual de distribución se debió a las condiciones ambientales compartidas entre la Puna y Patagonia austral durante la transición Pleistoceno-Holoceno. La extinción de V. vicugna se habría debido al impacto de los cambios climáticos ocurridos al inicio del Holoceno producto de su dieta pastadora y etología no migratoria y territorial, a lo que se habría sumado una caza por parte de depredadores humanos y no humanos.Palabras clave: género Vicugna, osteometría, Pleistoceno, Patagonia AbstractThis contribution presents the results of single and multi-variable osteometric analyses performed on a sample of short bones and phalanxes assigned to Vicugna sp. from Lago Sofía Cave 4 site (13500 – 11000 BP, Región de Magallanes, Chile. The elements analyzed show a similar size to the reference collections for Vicugna vicugna, and do not exceed the metrics for the pampean pleistocenic specimens of Vicugna gracilis. This confirms the morphological and ancient DNA data that indicated the presence of vicuña in southern Chilean Patagonia. The taxonomic, biogeographic and palaeoecologic discussion of these results, suggests that the presence of this

  10. A new sauropodomorph dinosaur from the Early Jurassic of Patagonia and the origin and evolution of the sauropod-type sacrum.

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    Diego Pol

    Full Text Available BACKGROUND: The origin of sauropod dinosaurs is one of the major landmarks of dinosaur evolution but is still poorly understood. This drastic transformation involved major skeletal modifications, including a shift from the small and gracile condition of primitive sauropodomorphs to the gigantic and quadrupedal condition of sauropods. Recent findings in the Late Triassic-Early Jurassic of Gondwana provide critical evidence to understand the origin and early evolution of sauropods. METHODOLOGY/PRINCIPAL FINDINGS: A new sauropodomorph dinosaur, Leonerasaurus taquetrensis gen. et sp. nov., is described from the Las Leoneras Formation of Central Patagonia (Argentina. The new taxon is diagnosed by the presence of anterior unserrated teeth with a low spoon-shaped crown, amphicoelous and acamerate vertebral centra, four sacral vertebrae, and humeral deltopectoral crest low and medially deflected along its distal half. The phylogenetic analysis depicts Leonerasaurus as one of the closest outgroups of Sauropoda, being the sister taxon of a clade of large bodied taxa composed of Melanorosaurus and Sauropoda. CONCLUSIONS/SIGNIFICANCE: The dental and postcranial anatomy of Leonerasaurus supports its close affinities with basal sauropods. Despite the small size and plesiomorphic skeletal anatomy of Leonerasaurus, the four vertebrae that compose its sacrum resemble that of the large-bodied primitive sauropods. This shows that the appearance of the sauropod-type of sacrum predated the marked increase in body size that characterizes the origins of sauropods, rejecting a causal explanation and evolutionary linkage between this sacral configuration and body size. Alternative phylogenetic placements of Leonerasaurus as a basal anchisaurian imply a convergent acquisition of the sauropod-type sacrum in the new small-bodied taxon, also rejecting an evolutionary dependence of sacral configuration and body size in sauropodomorphs. This and other recent discoveries are

  11. Latest Pleistocene and Holocene glacial events in the Colonia valley, Northern Patagonia Icefield, southern Chile

    Science.gov (United States)

    Nimick, David A.; Mcgrath, Daniel; Mahan, Shannon; Friesen, Beverly A.; Leidich, Jonathan

    2016-01-01

    The Northern Patagonia Icefield (NPI) is the primary glaciated terrain worldwide at its latitude (46.5–47.5°S), and constraining its glacial history provides unique information for reconstructing Southern Hemisphere paleoclimate. The Colonia Glacier is the largest outlet glacier draining the eastern NPI. Ages were determined using dendrochronology, lichenometry, radiocarbon, cosmogenic 10Be and optically stimulated luminescence. Dated moraines in the Colonia valley defined advances at 13.2 ± 0.95, 11.0 ± 0.47 and 4.96 ± 0.21 ka, with the last being the first constraint on the onset of Neoglaciation for the eastern NPI from a directly dated landform. Dating in the tributary Cachet valley, which contains an ice-dammed lake during periods of Colonia Glacier expansion, defined an advance at ca. 2.95 ± 0.21 ka, periods of advancement at 810 ± 49 cal a BP and 245 ± 13 cal a BP, and retreat during the intervening periods. Recent Colonia Glacier thinning, which began in the late 1800s, opened a lower-elevation outlet channel for Lago Cachet Dos in ca. 1960. Our data provide the most comprehensive set of Latest Pleistocene and Holocene ages for a single NPI outlet glacier and expand previously developed NPI glacial chronologies.

  12. Gamma irradiation as a phytosanitary treatment for fresh pome fruits produced in Patagonia

    Science.gov (United States)

    Pérez, J.; Lires, C.; Horak, C.; Pawlak, E.; Docters, A.; Kairiyama, E.

    2009-07-01

    Argentina produces 1.8 million tons/year of apples ( Malus domestica L.) and pears ( Pyrus communis L.) in the Patagonia region. Cydia pomonella, codling moth, and Grapholita molesta, Oriental fruit moth, ( Lepidoptera: Tortricidae) are quarantine pests in pome fruits. Irradiation is a promising phytosanitary treatment because a dose of 200 Gy completely prevents pest adult emergence. A pilot irradiation process of commercially packaged 'Red Delicious' apples and 'Packham's Triumph' pears was performed in an irradiation facility with a Cobalt 60 source. Quality analyses were carried out at 0, 2, 4, 6 and 8 months of storage (1 °C, RH 99%) to evaluate fruit tolerance at 200, 400 and 800 Gy. Irradiation at 200 and 400 Gy had no undesirable effects on fruit quality (pulp firmness, external colour, soluble solids content (SSC), titratable acidity (TA) and sensory evaluations). Irradiation of 'Red Delicious' apples and 'Packham's Triumph' pears can be applied as a commercial quarantine treatment with a minimum absorbed dose of 200 Gy (to control codling moth and Oriental fruit moth) and <800 Gy (according to quality results).

  13. Microbial life in a fjord: metagenomic analysis of a microbial mat in Chilean patagonia.

    Directory of Open Access Journals (Sweden)

    Juan A Ugalde

    Full Text Available The current study describes the taxonomic and functional composition of metagenomic sequences obtained from a filamentous microbial mat isolated from the Comau fjord, located in the northernmost part of the Chilean Patagonia. The taxonomic composition of the microbial community showed a high proportion of members of the Gammaproteobacteria, including a high number of sequences that were recruited to the genomes of Moritella marina MP-1 and Colwelliapsycherythraea 34H, suggesting the presence of populations related to these two psychrophilic bacterial species. Functional analysis of the community indicated a high proportion of genes coding for the transport and metabolism of amino acids, as well as in energy production. Among the energy production functions, we found protein-coding genes for sulfate and nitrate reduction, both processes associated with Gammaproteobacteria-related sequences. This report provides the first examination of the taxonomic composition and genetic diversity associated with these conspicuous microbial mat communities and provides a framework for future microbial studies in the Comau fjord.

  14. Microbial Life in a Fjord: Metagenomic Analysis of a Microbial Mat in Chilean Patagonia

    Science.gov (United States)

    Ugalde, Juan A.; Gallardo, Maria J.; Belmar, Camila; Muñoz, Práxedes; Ruiz-Tagle, Nathaly; Ferrada-Fuentes, Sandra; Espinoza, Carola; Allen, Eric E.; Gallardo, Victor A.

    2013-01-01

    The current study describes the taxonomic and functional composition of metagenomic sequences obtained from a filamentous microbial mat isolated from the Comau fjord, located in the northernmost part of the Chilean Patagonia. The taxonomic composition of the microbial community showed a high proportion of members of the Gammaproteobacteria, including a high number of sequences that were recruited to the genomes of Moritella marina MP-1 and Colwelliapsycherythraea 34H, suggesting the presence of populations related to these two psychrophilic bacterial species. Functional analysis of the community indicated a high proportion of genes coding for the transport and metabolism of amino acids, as well as in energy production. Among the energy production functions, we found protein-coding genes for sulfate and nitrate reduction, both processes associated with Gammaproteobacteria-related sequences. This report provides the first examination of the taxonomic composition and genetic diversity associated with these conspicuous microbial mat communities and provides a framework for future microbial studies in the Comau fjord. PMID:24015199

  15. Condiciones productivas y exigencias de calidad en la fruticultura de la Patagonia argentina

    Directory of Open Access Journals (Sweden)

    Belén Alvaro

    2013-01-01

    Full Text Available La producción alimentaria está regida, a partir de los años noventa, por requerimientos de calidad e inocuidad que modifican sustancialmente las condiciones productivas del eslabón primario, en el marco de una reestructuración del sistema agroalimentario mundial. El caso en estudio aborda la conformación social de la cadena frutícola localizada en el norte de la Patagonia argentina, donde estos requerimientos se formalizan, entre otros, en las buenas prácticas agrícolas, abordadas como dispositivos de control que interpelan y vuelven complejas las condiciones de reproducción social de los chacareros, como productores independientes en la cadena, con impactos en sus trayectorias vitales y productivas. Se consultaron fuentes secundarias, y se realizó el relevamiento primario de casos. Las conclusiones se inscriben en las tensiones entre configuraciones productivas locales y avances de los controles del capital concentrado.

  16. New species of dictyostelids from Patagonia and Tierra del Fuego, Argentina.

    Science.gov (United States)

    Vadell, Eduardo M; Cavender, James C; Romeralo, Maria; Edwards, Sally M; Stephenson, Steven L; Baldauf, Sandra L

    2011-01-01

    In late Jan and early Feb 2005 samples for isolation of dictyostelid cellular slime molds (dictyostelids) were collected in five different provinces and from six national parks (all located 39-55°S) in Patagonia and Tierra del Fuego, Argentina. Southern beech (Nothofagus) forests represented the primary vegetation type investigated, but some samples were obtained from Patagonian steppe, alpine meadows, Valdivian temperate rainforests and coniferous forests dominated by Araucaria, Austrocedrus and Fitzroya. Among the dictyostelids isolated from the samples we collected were seven species new to science. These species (Dictyostelium austroandinum, D. chordatum, D. fasciculoideum, D. gargantuum, D. leptosomopsis, D. valdivianum and Polysphondylium patagonicum) are described herein on the basis of both morphology and molecular (SSU rDNA) data. One of the new species, D. gargantuum, is one of the largest representatives of the group reported to date. Another unusual species, D. chordatum, produces long interwoven sorocarps that do not appear to respond to a spacing gas similar to the condition first noted in D. implicatum.

  17. Radar remote sensing of wind-driven land degradation processes in northeastern Patagonia.

    Science.gov (United States)

    del Valle, H F; Blanco, P D; Metternicht, G I; Zinck, J A

    2010-01-01

    Wind-driven land degradation negatively impacts on rangeland production and infrastructure in the Valdes Peninsula, northeastern Patagonia. The Valdes Peninsula has the most noticeable dunefields of the Patagonian drylands. Wind erosion has been assessed at different scales in this region, but often with limited data. In general, terrain features caused by wind activity are better discriminated by active microwaves than by sensors operating in the visible and infrared regions of the electromagnetic spectrum. This paper aims to analyze wind-driven land degradation processes that control the radar backscatter observed in different sources of radar imagery. We used subsets derived from SIR-C, ERS-1 and 2, ENVISAT ASAR, RADARSAT-1, and ALOS PALSAR data. The visibility of aeolian features on radar images is mostly a function of wavelength, polarization, and incidence angle. Stabilized sand deposits are clearly observed in radar images, with defined edges but also signals of ongoing wind erosion. One of the most conspicuous features corresponds to old track sand dunes, a mixture of active and inactive barchanoid ridges and parabolic dunes. This is a clear example of deactivation of migrating dunes under the influence of vegetation. The L-band data reveal details of these sand ridges, whereas the C-band data only allow detecting a few of the larger tracks. The results of this study enable us to make recommendations about the utility of some radar sensor configurations for wind-driven land degradation reconnaissance in mid-latitude regions.

  18. Muscular reconstruction and functional morphology of the forelimb of early Miocene sloths (Xenarthra, Folivora) of Patagonia.

    Science.gov (United States)

    Toledo, Néstor; Bargo, M Susana; Vizcaíno, Sergio F

    2013-02-01

    Early Miocene sloths are represented by a diversity of forms ranging from 38 to 95 kg, being registered mainly from Santacrucian Age deposits in southern-most shores of Patagonia, Argentina. Their postcranial skeleton differs markedly in shape from those of their closest living relatives (arboreal forms of less than 10 kg), Bradypus and Choloepus. In order to gain insight on functional properties of the Santacrucian sloths forelimb, musculature was reconstructed and a comparative, qualitative morphofunctional analysis was performed, allowing proposing hypotheses about biological role of the limb in substrate preferences, and locomotor strategies. The anatomy of the forelimb of Santacrucian sloths resembles more closely extant anteaters such as Tamandua and Myrmecophaga, due to the robustness of the elements, development of features related to attachment of ligaments and muscles, and conservative, pentadactylous, and strong-clawed manus. The reconstructed forelimb musculature was very well developed and resembles that of extant Pilosa (especially anteaters), although retaining the basic muscular configuration of generalized mammals. This musculature allowed application of powerful forces, especially in adduction of the forelimb, flexion and extension of the antebrachium, and manual prehension. These functional properties are congruent with both climbing and digging activities, and provide support for proposed Santacrucian sloths as good climbing mammals, possibly arboreal or semiarboreal, being also capable diggers. Their climbing strategies were limited, thus these forms relied mainly on great muscular strength and curved claws of the manus to move cautiously on branches.

  19. Gamma irradiation as a phytosanitary treatment for fresh pome fruits produced in Patagonia

    Energy Technology Data Exchange (ETDEWEB)

    Perez, J.; Lires, C.; Horak, C.; Pawlak, E.; Docters, A. [Comision Nacional de Energia Atomica, Centro Atomico Ezeiza Presbitero Juan Gonzalez y Aragon No. 15, (B1802AYA) Ezeiza, Buenos Aires (Argentina); Kairiyama, E. [Comision Nacional de Energia Atomica, Centro Atomico Ezeiza Presbitero Juan Gonzalez y Aragon No. 15, (B1802AYA) Ezeiza, Buenos Aires (Argentina)], E-mail: kairiyam@cae.cnea.gov.ar

    2009-07-15

    Argentina produces 1.8 million tons/year of apples (Malus domestica L.) and pears (Pyrus communis L.) in the Patagonia region. Cydia pomonella, codling moth, and Grapholita molesta, Oriental fruit moth, (Lepidoptera: Tortricidae) are quarantine pests in pome fruits. Irradiation is a promising phytosanitary treatment because a dose of 200 Gy completely prevents pest adult emergence. A pilot irradiation process of commercially packaged 'Red Delicious' apples and 'Packham's Triumph' pears was performed in an irradiation facility with a Cobalt 60 source. Quality analyses were carried out at 0, 2, 4, 6 and 8 months of storage (1 deg. C, RH 99%) to evaluate fruit tolerance at 200, 400 and 800 Gy. Irradiation at 200 and 400 Gy had no undesirable effects on fruit quality (pulp firmness, external colour, soluble solids content (SSC), titratable acidity (TA) and sensory evaluations). Irradiation of 'Red Delicious' apples and 'Packham's Triumph' pears can be applied as a commercial quarantine treatment with a minimum absorbed dose of 200 Gy (to control codling moth and Oriental fruit moth) and <800 Gy (according to quality results)

  20. Mercury and selenium in the food web of Lake Nahuel Huapi, Patagonia, Argentina.

    Science.gov (United States)

    Arcagni, Marina; Rizzo, Andrea; Juncos, Romina; Pavlin, Majda; Campbell, Linda M; Arribére, María A; Horvat, Milena; Ribeiro Guevara, Sergio

    2017-01-01

    Despite located far from point sources of Hg pollution, high concentrations were recorded in plankton from the deep oligotrophic Lake Nahuel Huapi, located in North Patagonia. Native and introduced top predator fish with differing feeding habits are a valuable economic resource to the region. Hence, Hg and Se trophic interactions and pathways to these fish were assessed in the food web of this lake at three sites, using stable nitrogen and carbon isotopes. As expected based on the high THg in plankton, mercury did not biomagnify in the food web of Lake Nahuel Huapi, as most of the THg in plankton is in the inorganic form. As was observed in other aquatic systems, Se did not biomagnify either. When trophic pathways to top predator fish were analyzed, they showed that THg biomagnified in the food chains of native fish but biodiluted in the food chains of introduced salmonids. A more benthic diet, typical of native fish, resulted in higher [THg] bioaccumulation than a more pelagic or mixed diet, as in the case of introduced fish. Se:THg molar ratios were higher than 1 in all the fish species, indicating that Se might be offering a natural protection against Hg toxicity.

  1. The Domuyo volcanic system: An enormous geothermal resource in Argentine Patagonia

    Science.gov (United States)

    Chiodini, Giovanni; Liccioli, Caterina; Vaselli, Orlando; Calabrese, Sergio; Tassi, Franco; Caliro, Stefano; Caselli, Alberto; Agusto, Mariano; D'Alessandro, Walter

    2014-03-01

    A geochemical survey of the main thermal waters discharging in the southwestern part of the Domuyo volcanic complex (Argentina), where the latest volcanic activity dates to 0.11 Ma, has highlighted the extraordinarily high heat loss from this remote site in Patagonia. The thermal water discharges are mostly Na-Cl in composition and have TDS values up to 3.78 g L- 1 (El Humazo). A simple hydrogeochemical approach shows that 1,100 to 1,300 kg s- 1 of boiling waters, which have been affected by shallow steam separation, flow into the main drainage of the area (Rio Varvarco). A dramatic increase of the most conservative species such as Na, Cl and Li from the Rio Varvarco from upstream to downstream was observed and related solely to the contribution of hydrothermal fluids. The equilibrium temperatures of the discharging thermal fluids, calculated on the basis of the Na-K-Mg geothermometer, are between 190 °C and 230 °C. If we refer to a liquid originally at 220 °C (enthalpy = 944 J g- 1), the thermal energy release can be estimated as high as 1.1 ± 0.2 GW, a value that is much higher than the natural release of heat in other important geothermal fields worldwide, e.g., Mutnovsky (Russia), Wairakei (New Zealand) and Lassen Peak (USA). This value is the second highest measured advective heat flux from any hydrothermal system on Earth after Yellowstone.

  2. Spatial dynamics of Fabiana imbricata shrublands in northwestern Patagonia in relation to natural fires

    Directory of Open Access Journals (Sweden)

    L. Ghermandi

    2010-05-01

    Full Text Available Fire is a critical disturbance in the structuring and functioning of most Mediterranean ecosystems. In northwestern Patagonia, vegetation patterns are strongly influenced by fire and environmental heterogeneity. Dendroecology, together with satellite imagery and GIS, have been demonstrated to be useful tools in studies that relate to fire effects with patches, patterns and species dynamics at landscape scale. Such studies can be approached from landscape ecology, which has evolved in the last years supported by the development of remote sensing and GIS technologies. This study evaluates the spatial dynamic of F. imbricata in response to fire using remote sensing, GIS and dendrochronology techniques, at landscape scale. Two sites were evaluated and one of them was affected by fire in the year 1999. The digital processing images (using the NBR spectral index and the dendroecological analysis verified this. A fire, occurring in 1978, was also detected by the analysis of F. imbricata growth rings. The relation between F. imbricata shrubland dynamics and spatial configuration with fire, land topography and hydrography was established in the study area.

  3. Bacterial composition of microbial mats in hot springs in Northern Patagonia: variations with seasons and temperature.

    Science.gov (United States)

    Mackenzie, Roy; Pedrós-Alió, Carlos; Díez, Beatriz

    2013-01-01

    Seasonal shifts in bacterial diversity of microbial mats were analyzed in three hot springs (39-68 °C) of Patagonia, using culture-independent methods. Three major bacterial groups were detected in all springs: Phyla Cyanobacteria and Bacteroidetes, and Order Thermales. Proteobacteria, Acidobacteria and Green Non-Sulfur Bacteria were also detected in small amounts and only in some samples. Thermophilic filamentous heterocyst-containing Mastigocladus were dominant Cyanobacteria in Porcelana Hot Spring and Geyser, and Calothrix in Cahuelmó, followed by the filamentous non-heterocyst Leptolyngbya and Oscillatoria. Bacteroidetes were detected in a wide temperature range and their relative abundance increased with decreasing temperature in almost all samples. Two Meiothermus populations with different temperature optima were found. Overall, fingerprinting analysis with universal bacterial primers showed high similarities within each hot spring despite differences in temperature. On the other hand, Cahuelmó Hot Spring showed a lower resemblance among samples. Porcelana Hot Spring and Porcelana Geyser were rather similar to each other, possibly due to a common geological substrate given their geographic proximity. This was even more evident with specific cyanobacterial primers. The different geological substrate and the seawater influence in Cahuelmó might have caused the differences in the microbial community structure with the other two hot springs.

  4. High resolution isotopic ages for the early Miocene "Patagoniense" transgression in Southwest Patagonia: Stratigraphic implications

    Science.gov (United States)

    Cuitiño, José I.; Pimentel, Marcio M.; Ventura Santos, Roberto; Scasso, Roberto A.

    2012-10-01

    The classical marine Patagoniense succession at Lago Argentino, southwestern Patagonia (Argentina), known as Estancia 25 de Mayo Formation, was dated by radiometric U-Pb on zircon grains from pyroclastic rocks and 87Sr/86Sr ratio on calcitic oyster shells. U-Pb data yielded an age of 19.14 Ma for the lower portion of the Patagoniense succession and 18.85 Ma for the lowermost part of the overlying Santa Cruz Formation. 87Sr/86Sr data yielded ages ranging from 20.05 Ma at the lower part and 19.1 Ma for the upper portion of the Estancia 25 de Mayo Formation, in good agreement with respect to the U-Pb results. Our results constrain the age of these beds entirely into the early Miocene Burdigalian stage, and locally into the Superpatagoniense stage. Correlation with other Patagoniense units in Santa Cruz, especially in the westernmost parts of the Austral Basin, reveals the existence of a shallow and extended sea, and lack of correlation with global sea-level highstands suggests a local Andean tectonic overprint as the cause of the sea level rise.

  5. Interactions among four parasite species in an amphipod population from Patagonia.

    Science.gov (United States)

    Rauque, C A; Semenas, L

    2013-03-01

    Parasites commonly share their hosts with specimens of the same or different parasite species, resulting in multiple parasites obtaining resources from the same host. This could potentially lead to conflicts between co-infecting parasites, especially at high infection intensities. In Pool Los Juncos (Patagonia, Argentina), the amphipod Hyalella patagonica is an intermediate host to three parasites that mature in birds (the acanthocephalan Pseudocorynosoma sp. and larval stages of two Cyclophyllidea cestodes), in addition to a microsporidian (Thelohania sp.), whose life cycle is unknown, but very likely to be monoxenous. The aim of this study was to describe interactions between these parasite species in their amphipod host population. Amphipods were collected monthly between June 2002 and January 2004 to assess parasite infection. Infection prevalence and mean intensity were greatest in larger male amphipods for all parasite species. We also found a positive association between Thelohania sp. and both Pseudocorynosoma sp. and Cyclophyllidea sp. 1 infections, though Pseudocorynosoma sp. and Cyclophyllidea sp. 1 were negatively associated with each other. We conclude that contrasting associations between parasite species may be associated with competition for both food intake and space in the haemocoel.

  6. Drainage network over the migrating front of dynamic uplift in Patagonia

    Science.gov (United States)

    Jeandet, Louise; Robert, Xavier; Audin, Laurence; Husson, Laurent; Guillaume, Benjamin

    2016-04-01

    Dynamic topography disturbs the regional morphology at long wavelength and with very low topographic gradients. Nevertheless, fluvial erosion and the drainage pattern should respond to the spatial and temporal topographic variations. In Patagonia, the mid-Miocene, opening and northward migration of an asthenospheric window beneath the South American plate triggered a northward propagating wave of dynamic topography. Based on a morphometric analysis, we explore the long-wavelength response of the drainage system to the recent dynamics of the continental lithosphere. Our analysis of Patagonian rivers (stream profile analysis) and basins (R/Sr analysis) shows a transient state of the drainage network responding to a likely recent signal that prevails at the latitudes of the Chile Triple Junction in Argentina. Moreover, the distribution of the perturbation signal among the drainage network shows a South-to-North gradient, with the low Strahler order tributaries more affected with increasing latitudes. We interpret this observation as the differential timing of response to a Northward propagating signal of dynamic topography. We further use the geometry of the drainage network combined to numerical model predictions to infer the characteristic response time of the surface processes. While the main tributaries respond within ~1-3 Ma, the lower order remain disturbed for longer times. This observation is further supported by the persistently high mean elevation where incision is high, which we take as indicative of the fact that erosion has not yet thoroughly achieved its resurfacing action.

  7. In Vitro Antimicrobial Activity of Embothrium coccineum Used as Traditional Medicine in Patagonia against Multiresistant Bacteria

    Directory of Open Access Journals (Sweden)

    Nicole Canales

    2016-10-01

    Full Text Available Embothrium coccineum J.R. Forst. & G. Forst is an evergreen tree that has been used as a folk remedy for the treatment of neuralgia, tooth pains, wound healing, and glandular conditions, as well as an antiseptic agent against bacterial infection. The antibacterial activities of sequential extracts (hexane, dichloromethane, ethyl acetate, and ethanol from the leaves of E. coccineum were evaluated by means of the micro-dilution assay against six (Escherichia coli; Klebsiella pneumoniae; Proteus mirabilis; Pseudomonas aeruginosa; Staphylococcus aureus and Streptococcus pyogenes multiresistant bacteria strains. Ethyl acetate extract showed the best spectra of antibacterial activity against all tested bacteria, and was analyzed by gas chromatography–mass spectrometry (GC-MS for its composition. The results of the present work provide useful baseline information for the potential development and use of nanoparticles and/or nanofibers doped with extracts of E. coccineum in the fight against multiresistant bacteria, which would allow the validation of the traditional use of E. coccineum by native peoples of Patagonia as an antimicrobial agent in the biomedical Field.

  8. An assessment of oil pollution in the coastal zone of patagonia, Argentina.

    Science.gov (United States)

    Commendatore, Marta Graciela; Esteves, José Luis

    2007-11-01

    The Patagonian coast is considered a relatively pristine environment. However, studies conducted along coastal Patagonia have showed hydrocarbon pollution mostly concentrated at ports that have fishing, oil loading, general merchant, and/or tourist activities. A high value of total aliphatic hydrocarbons (TAH) was found at the Rawson fishing port (741 microg/g dw). In other ports with and without petroleum-related activities, hydrocarbon values were approximately 100 microg/g dw. The highest values for TAH and total aromatic hydrocarbons (TArH) were found in Faro Aristizábal, north of San Jorge gulf (1304 and 737 microg/g dw, respectively). This is very likely the result of petroleum-related activities at the Comodoro Rivadavia, Caleta Cordova, and Caleta Olivia ports located within this gulf. In other coastal areas away from potential anthropogenic sources, hydrocarbon values were less than 2 and 3 microg/g dw for TAH and TArH, respectively. This review of published and unpublished information suggests that ports are important oil pollution sources in the Patagonian coast. More detailed studies are needed to evaluate the area affected by port activities, to understand the mechanisms of hydrocarbon distribution in surrounding environments, and to assess bioaccumulation in marine organisms. Despite that some regulations exist to control oil pollution derived from port and docked vessel activities, new and stricter management guidelines should be implemented.

  9. Discovery of a short-necked sauropod dinosaur from the Late Jurassic period of Patagonia.

    Science.gov (United States)

    Rauhut, Oliver W M; Remes, Kristian; Fechner, Regina; Cladera, Gerardo; Puerta, Pablo

    2005-06-01

    Sauropod dinosaurs are one of the most conspicuous groups of Mesozoic terrestrial vertebrates. They show general trends towards an overall increase in size and elongation of the neck, by means of considerable elongation of the length of individual vertebrae and a cervical vertebra count that, in some cases, increases to 19 (ref. 1). The long neck is a particular hallmark of sauropod dinosaurs and is usually regarded as a key feeding adaptation. Here we describe a new dicraeosaurid sauropod, from the latest Jurassic period of Patagonia, that has a particularly short neck. With a neck that is about 40% shorter than in other known dicraeosaurs, this taxon demonstrates a trend opposite to that seen in most sauropods and indicates that the ecology of dicraeosaurids might have differed considerably from that of other sauropods. The new taxon indicates that there was a rapid radiation and dispersal of dicraeosaurids in the Late Jurassic of the Southern Hemisphere, after the separation of Gondwana from the northern continents by the late Middle Jurassic.

  10. Glacial lake drainage in Patagonia (13-8 kyr) and response of the adjacent Pacific Ocean.

    Science.gov (United States)

    Glasser, Neil F; Jansson, Krister N; Duller, Geoffrey A T; Singarayer, Joy; Holloway, Max; Harrison, Stephan

    2016-02-12

    Large freshwater lakes formed in North America and Europe during deglaciation following the Last Glacial Maximum. Rapid drainage of these lakes into the Oceans resulted in abrupt perturbations in climate, including the Younger Dryas and 8.2 kyr cooling events. In the mid-latitudes of the Southern Hemisphere major glacial lakes also formed and drained during deglaciation but little is known about the magnitude, organization and timing of these drainage events and their effect on regional climate. We use 16 new single-grain optically stimulated luminescence (OSL) dates to define three stages of rapid glacial lake drainage in the Lago General Carrera/Lago Buenos Aires and Lago Cohrane/Pueyrredón basins of Patagonia and provide the first assessment of the effects of lake drainage on the Pacific Ocean. Lake drainage occurred between 13 and 8 kyr ago and was initially gradual eastward into the Atlantic, then subsequently reorganized westward into the Pacific as new drainage routes opened up during Patagonian Ice Sheet deglaciation. Coupled ocean-atmosphere model experiments using HadCM3 with an imposed freshwater surface "hosing" to simulate glacial lake drainage suggest that a negative salinity anomaly was advected south around Cape Horn, resulting in brief but significant impacts on coastal ocean vertical mixing and regional climate.

  11. Nuisance ecology: do scavenging condors exact foraging costs on pumas in Patagonia?

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    L Mark Elbroch

    Full Text Available Predation risk describes the energetic cost an animal suffers when making a trade off between maximizing energy intake and minimizing threats to its survival. We tested whether Andean condors (Vultur gryphus influenced the foraging behaviors of a top predator in Patagonia, the puma (Puma concolor, in ways comparable to direct risks of predation for prey to address three questions: 1 Do condors exact a foraging cost on pumas?; 2 If so, do pumas exhibit behaviors indicative of these risks?; and 3 Do pumas display predictable behaviors associated with prey species foraging in risky environments? Using GPS location data, we located 433 kill sites of 9 pumas and quantified their kill rates. Based upon time pumas spent at a carcass, we quantified handling time. Pumas abandoned >10% of edible meat at 133 of 266 large carcasses after a single night, and did so most often in open grasslands where their carcasses were easily detected by condors. Our data suggested that condors exacted foraging costs on pumas by significantly decreasing puma handling times at carcasses, and that pumas increased their kill rates by 50% relative to those reported for North America to compensate for these losses. Finally, we determined that the relative risks of detection and associated harassment by condors, rather than prey densities, explained puma "giving up times" (GUTs across structurally variable risk classes in the study area, and that, like many prey species, pumas disproportionately hunted in high-risk, high-resource reward areas.

  12. New evidence of the sabertooth cat Smilodon (Carnivora: Machairodontinae in the late Pleistocene of southern Chilean Patagonia Nueva evidencia del gato dientes de sable Smilodon (Carnivora: Machairodontinae en el Pleistoceno tardío de Patagonia meridional chilena

    Directory of Open Access Journals (Sweden)

    ALFREDO PRIETO

    2010-06-01

    Full Text Available Southern Patagonia is rich in late Pleistocene mammals, especially herbivores such as Camelids, Equids and Xenarthrans. Carnivores, on the other hand, are not commonly found in the paleontological record. One genus, Smilodon, is of particular interest because its presence in the region has not been demonstrated. In this paper, we present new fossil dental evidence that supports the presence of Smilodon populator (Lund in the region. This evidence corresponds to the most southern record of the genus in the world, and the final step in the colonization of South America after the Great American Biotic Interchange. An AMS radiocarbon date on teeth indicates that the remains from Southern Chilean Patagonia are the most recent record for the genus in South America.Surpatagonia es particularmente rica en mamíferos finiplesitocenos, particularmente camélidos, équidos y xenartros. Los carnívoros, por su parte, se encuentran representados en menor número en el registro paleontológico. Dentro de estos, el género Smilodon, es de particular interés debido a que su presencia en la región no ha sido convincentemente demostrada. En este trabajo presentamos evidencia dental que permite confirmar la presencia de Smilodon populator (Lund en la región. Esta evidencia corresponde al registro más sureño de este taxón y al paso final en la colonización de América del Sur después del Gran Intercambio Biótico Americano. Un fechado radiocarbónico directo AMS indica que los restos de Patagonia del Sur corresponden a los registros más tardíos para este género en el subcontinente.

  13. Trace elements deposition in the Tierra del Fuego region (south Patagonia) by using lichen transplants after the Puyehue-Cordón Caulle (north Patagonia) volcanic eruption in 2011.

    Science.gov (United States)

    Conti, Marcelo Enrique; Jasan, Raquel; Finoia, Maria Grazia; Iavicoli, Ivo; Plá, Rita

    2016-04-01

    Lichen Usnea barbata transplants were tested as a biomonitor of atmospheric deposition in an apparently pristine environment that is Tierra del Fuego region (Patagonia, Argentina). The present survey is connected with the volcanic eruption that started in north Patagonia on June 4, 2011 from the Puyehue-Cordón Caulle volcano, Chile (north Patagonia, at 1700 km of distance of our sampling sites). Lichens were collected in September 2011 (one month of exposure) and September 2012 (1 year of exposure) in 27 sites covering the northern region of the province where trees are not present. The atmospheric deposition of 27 elements by using Neutron Activation Analysis (NAA) was determined in the collected samples. The first aim of the study was to evaluate the influence of the volcanic eruption on the regional atmospheric deposition comparing our results with baseline data we determined in U. barbata in 2006 in the same sites. The second aim was to test possible patterns of bioaccumulation between the two sampling campaigns after the volcanic eruption. With respect to 2006 baseline levels, we found significant higher levels for As, Ba, Co, Cr, Cs, Na, Sb and U in lichens collected after 1 month of exposure (first sampling campaign--2011). Between the two sampling campaigns (2011-2012) after the eruption, lichens reflected the natural contamination by volcanic ashes with significantly higher median levels of Br, Cr, Fe, K, Na, Sc, and Se. Results confirmed the very good aptitude of U. barbata to reflect the levels of elements in the environment at global scale and to reflect the volcanic emissions at distant places. Volcanic eruptions cause the emission in the atmosphere of elevated levels of particulate matter. In this regard, our findings demonstrate the importance to evaluate the metal composition of the particles to avoid possible health effects.

  14. Mortality of the outbreak defoliator Ormiscodes amphimone (Lepidoptera: Saturniidae caused by natural enemies in northwestern Patagonia, Argentina Mortalidad del defoliador epidémico Ormiscodes amphimone (Lepidoptera: Saturniidae causada por enemigos naturales en el noroeste de la Patagonia Argentina

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    JUAN PARITSIS

    2012-03-01

    Full Text Available Outbreaks of the defoliator moth Ormiscodes amphimone are occurring more frequently in numerous Nothofagus forests of Patagonia. However, little is known about the life history of this species including its natural enemies as mortality agents. In this work we quantified mortality by parasitoids and generalist predators at the egg, larval and pupal life stages of O. amphimone in a Nothofagus pumilio (Poepp. & Endl. Krasser forest in northwestern Patagonia. Parasitism of eggs was relatively low (ca. 11 %, and we did not record significant larval predation by insectivorous birds. However, we recorded elevated mortality caused by larval parasitoids (ca. 50 % in third instar larvae and pupal predators (ca. 75 %, which suggests that these natural enemies could play a significant role in regulating O. amphimone populations. Our research is an initial step towards understanding the influence of natural enemies on O. amphimone population dynamics.Las irrupciones poblacionales de la polilla defoliadora Ormiscodes amphimone están ocurriendo de manera más frecuente en numerosos bosques de Nothofagus de la Patagonia. Sin embargo, se sabe poco de la historia natural de esta especie y, particularmente, de sus enemigos naturales. En este estudio se cuantificó la depredación de huevos, larvas y pupas de O. amphimone por parasitoides y otros depredadores en un bosque de Nothofagus pumilio (Poepp. & Endl. Krasser en el noroeste de la Patagonia. Se encontró que el parasitismo de huevos fue relativamente bajo (ca. 11 % y no se registró depredación significativa de larvas por aves insectívoras. No obstante, registramos niveles elevados de mortalidad causada por parasitoides de larvas (ca. 50 % en larvas en tercer instar y por depredadores de pupas (ca. 75 %, lo que parece indicar que estos enemigos naturales desempeñan un papel significativo en la regulación de poblaciones de O. amphimone. Este estudio representa un paso inicial hacia el entendimiento de la

  15. Transient simulations, empirical reconstructions and forcing mechanisms for the Mid-holocene hydrological climate in southern Patagonia

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Sebastian; Widmann, Martin; Jones, Julie [Institute for Coastal Research, GKSS Research Centre, Geesthacht (Germany); Haberzettl, Torsten; Ohlendorf, Christian; Zolitschka, Bernd [University of Bremen, Institute of Geography, Bremen (Germany); Luecke, Andreas; Mayr, Christoph [Research Centre Juelich, Institute of Chemistry and Dynamics of the Geosphere V, Juelich (Germany); Schaebitz, Frank [University of Cologne, Seminar for Geography and its Didactics, Cologne (Germany)

    2007-09-15

    This study investigates the atmospheric circulation in transient climate simulations with a coupled atmosphere-ocean general circulation model (GCM) for the mid-Holocene (MH) period 7-4.5 ka BP driven with combinations of orbital, solar and greenhouse gas forcings. The focus is on southern South America. Statistical downscaling models are derived from observational data and applied to the simulations to estimate precipitation in south-eastern Patagonia during the MH. These estimates are compared with lake level estimates for Laguna Potrok Aike (LPA) from sediments. Relative to pre-industrial conditions (i.e. 1550-1850), which show extraordinarily high lake levels, the proxy-based reconstructed lake levels during the MH are lower. The downscaled simulated circulation differences indicate higher LPA precipitation during the MH from March to August, higher annual means, and reduced precipitation from September to February. Thus the reconstructed lower LPA lake levels can not be explained solely by the simulated precipitation changes. Possible reasons for this discrepancy are discussed. Based on proxy data from southern South America hypotheses have also been proposed on the latitudinal position of the southern hemispheric westerlies (SHWs). In agreement with some of these hypotheses our simulations show an increased seasonal cycle of the latitudinal position of the SHWs during the MH, which can be explained by the orbital forcing. The simulations also show stronger SHWs over southern Patagonia during austral summer and weaker SHWs during winter. The downscaling model associates weaker SHWs with increased precipitation in the LPA region. However, this relationship is only moderate, and therefore the downscaling model does not support the assumption of a strong link between mean SHWs and precipitation over south-eastern Patagonia, which is the basis of many proxy-based hypotheses about the SHWs. (orig.)

  16. Robustez craneofacial y estrés masticatorio en cazadores recolectores del holoceno tardío de Patagonia

    OpenAIRE

    2005-01-01

    La morfología craneofacial de los grupos cazadores recolectores que habitaron Patagonia y Tierra del Fuego durante el Holoceno tardío (ca. 3000 años 1 4C BP a tiempos históricos) ha sido caracterizada por la presencia de elevados niveles de robustez no observados en otras poblaciones modernas (Lahr 1995; Lahr y Wright 1996). En este sentido, diversos estudios previos (Lahr y Wright 1996; Gonzalez-José 2003) destacan el pronunciado desarrollo de la región supraorbital y glabelar, de la cresta ...

  17. INVITACIÓN AL GEOTURISMO. REFLEXIONES SOBRE GEODIVERSIDAD Y POTENCIAL GEOTURÍSTICO EN LA PATAGONIA ARGENTINA

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    María de la Paloma Martínez Fernandez

    2013-12-01

    Full Text Available Geotourism as a type of nature tourism comes to fill an empty field on the use of geological resources of the landscape in Argentina. With an approach sustained by the ideas and progresses achieved along the last decades about sustainable tourism, geosites and geoparks are getting a boost worldwide. However, in Argentina this concept has not being incorporated yet within public or private touristic policies, despite owning a valuable geodiversity both scientific or aesthetically. Based on a review of concepts and foreign experiences on the subject, this article analyses the possibilities and parameters for geotourism developing in Argentinean Patagonia.

  18. Abundance estimates of southern right whales (Eubalaena australis) in Bahía San Antonio, Patagonia, Argentina

    OpenAIRE

    Vermeulen, Els; Cammareri, Alejandro

    2012-01-01

    Aerial surveys were conducted to estimate the abundance of southern right whales in Bahía San Antonio, a bay located in the north-western region of the San Matías Gulf (40°50¿S 64°50¿W), Rio Negro, Patagonia Argentina. The transect for the realization of aerial surveys was designed using the program DISTANCE 6.0 and consisted out of 14 North-South (up to S 40.9°) parallel transect lines with a 2.5km separation, covering a total surface of 418km² (mean coverage probability=0.78). Transect leng...

  19. U-Pb geochronology of the Santa Cruz Formation (early Miocene) at the Río Bote and Río Santa Cruz (southernmost Patagonia, Argentina): Implications for the correlation of fossil vertebrate localities

    Science.gov (United States)

    Cuitiño, José I.; Fernicola, Juan Carlos; Kohn, Matthew J.; Trayler, Robin; Naipauer, Maximiliano; Bargo, M. Susana; Kay, Richard F.; Vizcaíno, Sergio F.

    2016-10-01

    The early Miocene Santa Cruz Formation (SCF) in southern Patagonia hosts the Santacrucian South American Land Mammal Age (SALMA), whose age is known mainly from exposures along the Atlantic coast. Zircon U-Pb ages were obtained from intercalated tuffs from four inland sections of the SCF: 17.36 ± 0.63 Ma for the westernmost Río Bote locality, and 17.04 ± 0.55 Ma-16.32 ± 0.62 Ma for central Río Santa Cruz localities. All ages agree with the bounding age of underlying marine units and with equivalent strata in coastal exposures. New ages and available sedimentation rates imply time spans for each section of ∼18.2 to 17.36 Ma for Río Bote and 17.45-15.63 Ma for central Río Santa Cruz (Burdigalian). These estimates support the view that deposition of the SCF began at western localities ∼1 Ma earlier than at eastern localities, and that the central Río Santa Cruz localities expose the youngest SCF in southern Santa Cruz Province. Associated vertebrate faunas are consistent with our geochronologic synthesis, showing older (Notohippidian) taxa in western localities and younger (Santacrucian) taxa in central localities. The Notohippidian fauna (19.0-18.0 Ma) of the western localities is synchronous with Pinturan faunas (19.0-18.0 Ma), but older than Santacrucian faunas of the Río Santa Cruz (17.2-15.6 Ma) and coastal localities (18.0-16.2 Ma). The Santacrucian faunas of the central Río Santa Cruz localities temporally overlap Colloncuran (15.7 Ma), Friasian (16.5 Ma), and eastern Santacrucian faunas.

  20. Variability of Soil Types in Wetland Meadows in the South of the Chilean Patagonia Variabilidad de Tipos de Suelos en Las Vegas del Sur de la Patagonia Chilena

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    Ladislava Filipová

    2010-06-01

    Full Text Available The wetland meadows and pastures (vegas of the agricultural zone of the Magallanes Region and the Chilean Patagonia are productive and intensively exploited ecosystems. However, there is scarce data about the typology and the physical and chemical properties of the soils that determine the agricultural potential of vegas sites. Sampling of the main horizons of 47 soil profiles was conducted throughout the area. The profiles were described in the field and consequently classified according to the soil typology system of the WRB (IUSS Working Group WRB, 2006. Analyses of bulk and particle densities, capillary water capacity, pH (H2O, pH (CaCl2, texture, organic material, C:N ratio, electrical conductivity, effective cation exchange capacity, N, P, Ca-Mg-K-Na, exchangeable Al,  extractable Al, sulfur SO4(2-, B, and micronutrients (Cu-Zn-Mn-Fe were carried out.  The most frequently recorded groups of soil types in the studied vegas were Histosols - peat soils (20 profiles, and Fluvisols (19. Gleysols (3, Vertisols (1, Regosols (3, Solonchaks (1 and Solonetzs (1 were detected with much less frequency. There is also considerable variability in soil properties among and within the groups of soil types. The principal differences between the Histosols and the Fluvisols are the content of organic matter (often peat, pH level (related to the absence/presence of carbonates and associated soil properties. Fluvisols are more susceptible to salinization under conditions of aridity, whereas the main threat to Histosols is artificial drainage.Las praderas húmedas (vegas de la zona de uso agropecuario de la Región de Magallanes y la Antártica Chilena son ecosistemas productivos e intensamente explotados. No obstante, los conocimientos de los factores edáficos que determinan el potencial de las vegas son escasos. En este trabajo se realizó el muestreo de los horizontes principales de 47 perfiles del suelo de distintos tipos de vegas de la zona. Los perfiles

  1. Yacimientos de Halloysita en Mamil Choique,provincia de Río Negro, Patagonia Halloysite deposits in Mamil Choique, provinceof Río Negro, Patagonia

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    Fernanda Cravero

    2009-11-01

    Full Text Available En la provincia de Río Negro, al norte de la localidadde Mamil Choique, se explotan depósitos minerales cuyo material secomercializacomo caolín. Mediante estudios mineralógicos se determinó que el mineralprincipal es halloysita-(10 Å acompañado por cantidades menores de esmectita ycristobalita, siendo el primer yacimiento en la Argentina de este mineral y unode los pocos en el mundo. La halloysita se presenta en cristales tubulares,cilíndricos, menores a 0,5 µm de largo y condiámetros menores a 0,2 µm. Laidentificación de la halloysita-(10Å, corroborada mediante la intercalacióncon formamida, fue además posible debido al cuidado puesto en el embalaje ytraslado de las muestras pues este mineral se deshidrataa temperatura ambientetransformándose en halloysita- (7 Å, la cual es fácilmente confundida concaolinita. El mineral se presenta en zonas alteradas, sobre rocas ignimbritas decomposición riolítica pertenecientes a la Formación Huitrera de edad eocena.Este proceso se caracteriza principalmente por una intensa lixiviación de loselementos alcalinos y alcalinos térreos, y un incremento en la concentraciónrelativa de alúmina. El origen de la alteración no se ha establecido conprecisión, pero la mineralogía simple, la ausencia de minerales característicosy de elementos minoritarios o trazas de ambientes epitermales, sumado a laexistencia de un clima templado húmedo a partir del Eoceno, permite suponer unaformación de tipo meteórico. La determinación de halloysita plantea la revisiónen la utilización de material de este depósito, ya que este mineral poseepropiedades muy diferentes a las de los otros minerales del grupo del caolín.A white material in RíoNegro Province, Patagonia, has been mined as kaolin. Through mineralogicalstudies, the main mineral has been identified as halloysite-(10 Å with minoramounts of smectite and cristobalite. Halloysite tubes and cylinders are about0.5 µm long and 0.2 µm in diameter

  2. Tithonian age of dinosaur fossils in central Patagonian, Chile: U-Pb SHRIMP geochronology

    Science.gov (United States)

    Suárez, Manuel; De La Cruz, Rita; Fanning, Mark; Novas, Fernando; Salgado, Leonardo

    2016-11-01

    Three Tithonian concordant U-Pb SHRIMP zircon ages of 148.7 ± 1.4, 147.9 ± 1.5 and 147.0 ± 1.0 from tuffs intercalated in a clastic sedimentary succession with exceptional dinosaur bones including the new taxon Chilesaurus diegosuarezi gen. et sp. nov. exposed in central Chilean Patagonia (ca. 46°30'S) are reported herein. The fossiliferous beds accumulated in a synvolcanic fan delta reaching a shallow marine basin as indicated by glauconite present in some of the beds, and coeval with the beginning of the transgression of the Aysén Basin.

  3. Tithonian age of dinosaur fossils in central Patagonian, Chile: U-Pb SHRIMP geochronology

    Science.gov (United States)

    Suárez, Manuel; De La Cruz, Rita; Fanning, Mark; Novas, Fernando; Salgado, Leonardo

    2015-12-01

    Three Tithonian concordant U-Pb SHRIMP zircon ages of 148.7 ± 1.4, 147.9 ± 1.5 and 147.0 ± 1.0 from tuffs intercalated in a clastic sedimentary succession with exceptional dinosaur bones including the new taxon Chilesaurus diegosuarezi gen. et sp. nov. exposed in central Chilean Patagonia (ca. 46°30'S) are reported herein. The fossiliferous beds accumulated in a synvolcanic fan delta reaching a shallow marine basin as indicated by glauconite present in some of the beds, and coeval with the beginning of the transgression of the Aysén Basin.

  4. Cosmogenic age constraints on the last deglaciation in Southern Patagonia (49 - 50°S)

    Science.gov (United States)

    Murray, D. S.; Singer, B. S.; Carlson, A. E.; Caffee, M. W.

    2010-12-01

    The glacial-to-interglacial transition since the Last Glacial Maximum (LGM) reflects climate system dynamics and the mechanisms that force climate change. Numerous studies of glacier behavior, mainly in the Northern Hemisphere, have sought to delineate the LGM termination as well as post-LGM climate reversals. We know far less about the Southern Hemisphere, where the extent and timing of climate shifts, and the degree of linkage to changes in the Northern Hemisphere, remain uncertain. Quantifying the temperature and precipitation changes across southern South America can help assess the migration of precipitation patterns tied to the position of the Southern Westerlies and the Antarctic Polar Front. This data can also be used to detect the extent of temperature reversals across and between continents, such as the Antarctic Cold Reversal, if present. The testing of hypotheses regarding changes in global atmospheric and oceanic circulation since the LGM is partly dependent on the deconvolution of these two parameters. Glacial activity in the Southern Patagonian Icefield is highly sensitive to changes in temperature and precipitation, while the adjacent Andean rainshadow desert preserves a remarkably complete set of glacial deposits that span a wide transect of the southern mid-latitudes. These deposits are ideal for surface exposure dating, which in turn can provide a proxy for glacial activity and for changes in the factors that govern glacial mass balance. We use a new beryllium-10 production rate calibrated to the southern mid-latitudes to recalculate published surface exposure chronologies from Patagonia (46 to 53°S). The revised temporal framework indicates the presence of expansive ice from ~30 ka until regional retreat 17-18 ka, with a significant late-glacial re-advance or still-stand ending ~13 ka. This latitudinal transect is notable for a gap in glacial records between 49 and 50°S. New surface exposure age determinations from the Santa Teresita moraine

  5. Políticas de territorialización de indígenas en Chubut: Provincialización de las relaciones interétnicas a través del acceso a la tierra

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    Fabiana Nahuelquir

    2012-12-01

    Full Text Available En el presente artículo buscamos un doble objetivo. Por un lado, realizar una propuesta metodológica de lectura y análisis de presupuestos implícitos en los archivos estatales de tierras, construidos por el estado de la Provincia de Chubut. Por otro, nos abocamos al interior del discurso estatal a reconstruir las premisas que articularon las relaciones interétnicas entre el estado provincial y las familias indíge-nas, autoidentificadas como mapuche y mapuche-tehuelche. Tomamos como punto de partida con-ceptos como los de performance, contextualización y entextualización con la finalidad de (Bauman y Briggs, 2000 proponer una estrategia de análisis y reconstrucción de los marcos de referencia de los que partían los discursos estatales acerca del indígena y, al mismo tiempo, nos ocupamos de indagar cómo dichos marcos proveían de representaciones en curso a partir de las cuales se fijaba el sentido de las relaciones entre este grupo y el resto de la sociedad. El abordaje de las relaciones interétnicas entre el estado provincial y los indígenas requiere de un análisis desde una perspectiva histórica y multisituada. En consecuencia, cruzamos las sentencias de los archivos estatales con los posiciona-mientos de las narrativas indígenas y nos introducimos, entonces, en las particularidades de procesos conformación de comunidad provincial y de alterización de los indígenas al interior de las premisas que la primordializaban

  6. The origin of oriented lakes in the Andean foreland, Parque Nacional Torres del Paine (Chilean Patagonia)

    Science.gov (United States)

    Gonzales, Joseph; Aydin, Atilla

    2008-05-01

    The Parque Nacional Torres Del Paine and surrounding area in the Magallanes foreland basin in Chilean Patagonia is the site for numerous lakes fed by glaciers and rivers in the Andean highlands to the west. The lakes are elongate and have conspicuously systematic orientations. We hypothesize that the origin of the oriented lakes lies in the fault system, composed of a right-lateral strike-slip fault set oriented 58° from north, a left-lateral strike-slip set oriented 87°, and a thrust fault set oriented 167°, that exists within the underlying rocks. To test this hypothesis quantitatively, we determined the shape and orientation of the lakes by fitting each lake with an ellipse of appropriate aspect ratio, and later with multiple ellipses consistent with the composite geometry of some lakes. We then examined the faults in the area in terms of their kinematics, orientation and distribution. The distribution of lake orientations showed three distinct groups which appear to correspond to the three main fault groups. For lakes fitted with multiple ellipses, the difference in means between the right-lateral, left-lateral, and thrust faults and their corresponding groups of lakes are 3.05°, 1.57°, and 5.17°. Using a Kolmogorov-Smirnov (K-S) statistical test to compare the orientations of faults with respect to the lakes suggests that there is not a strongly significant difference between the fault orientations and the corresponding lake groups. These results indicate that the faults have a profound control on the orientation, shape, and distribution of the lakes. We attribute this to faults and their damage zones being weaker and therefore prone to a faster rate of erosion, and to stress perturbations associated with discontinuous faults resulting in localized high density fracturing and surface subsidence. These results have implications for lake and drainage system morphologies in other foreland basins along the Andes and other similar settings.

  7. Validating numerical simulations of snow avalanches using dendrochronology: the Cerro Ventana event in Northern Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    A. Casteller

    2008-05-01

    Full Text Available The damage caused by snow avalanches to property and human lives is underestimated in many regions around the world, especially where this natural hazard remains poorly documented. One such region is the Argentinean Andes, where numerous settlements are threatened almost every winter by large snow avalanches. On 1 September 2002, the largest tragedy in the history of Argentinean mountaineering took place at Cerro Ventana, Northern Patagonia: nine persons were killed and seven others injured by a snow avalanche. In this paper, we combine both numerical modeling and dendrochronological investigations to reconstruct this event. Using information released by local governmental authorities and compiled in the field, the avalanche event was numerically simulated using the avalanche dynamics programs AVAL-1D and RAMMS. Avalanche characteristics, such as extent and date were determined using dendrochronological techniques. Model simulation results were compared with documentary and tree-ring evidences for the 2002 event. Our results show a good agreement between the simulated projection of the avalanche and its reconstructed extent using tree-ring records. Differences between the observed and the simulated avalanche, principally related to the snow height deposition in the run-out zone, are mostly attributed to the low resolution of the digital elevation model used to represent the valley topography. The main contributions of this study are (1 to provide the first calibration of numerical avalanche models for the Patagonian Andes and (2 to highlight the potential of Nothofagus pumilio tree-ring records to reconstruct past snow-avalanche events in time and space. Future research should focus on testing this combined approach in other forested regions of the Andes.

  8. Biomarkers of environmental stress in gills of ribbed mussel Aulacomya atra atra (Nuevo Gulf, Northern Patagonia).

    Science.gov (United States)

    Giarratano, Erica; Gil, Mónica N; Malanga, Gabriela

    2014-09-01

    In this study, we assessed in gills of native ribbed mussels Aulacomya atra atra from three sites within Nuevo Gulf (Northern Patagonia) several biomarkers such as reactive oxygen species (ROS), lipid radicals (LR), malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST) and metallothionein (MT). Furthermore, concentrations of main trace metals (Fe, Al, Zn, Cu, Cd and Pb) were quantified in mussel tissue. Results showed significant induction of SOD, GST, MT and MDA, as well as, higher concentration of Fe, Al and Cd in winter than in summer. The high MDA content measured in mussels from Folías Wreck seemed to be caused by the very high levels of Fe that would come from the corrosion of the vessel. Mussels from the control site Punta Cuevas presented the lowest levels of Cd and the highest of Al in winter. Despite positive correlations were found between Al and GST and MT, no spatial differentiation was detected in those biomarkers. On the other hand, MT was only related to Al been most likely influenced by environmental variables than by the trace metals. It has to be highlighted that the relationship detected among water temperature, nutrients and antioxidant responses in gills is probably related to the fact that this tissue is in direct contact with water and it is sensitive to its fluctuations. Taking into account that mussel gill is a tissue actively proliferating and the first target of contaminants present in water, so that changes in its antioxidant system can provide an earlier warning signal than in other tissues.

  9. Fluid typing and tortuosity analysis with NMR-DE techniques in volcaniclastic reservoirs, Patagonia/Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Bustos, Ulises Daniel [Schlumberger Argentina S.A., Buenos Aires (Argentina); Breda, Eduardo Walter [Repsol YPF Comodoro Rivadavia, Chubut (Argentina)

    2004-07-01

    Alternative hydrocarbon-detection techniques are used to differentiate water from hydrocarbon where resistivity-based methods are difficult to apply, such as freshwater reservoirs and complex lithologies. One of these areas is represented by the complex volcaniclastic freshwater reservoirs in the Golfo San Jorge basin, Patagonia Argentina, where water and oil have often identical response on conventional logs. Some advances in hydrocarbon identification based on nuclear magnetic resonance (NMR) techniques were achieved in long T1 environments (very light oils, gas) in the Golfo San Jorge basin by previous NMR fluid typing methods. However, since medium to heavy oils are commonly present in these intervals, hydrocarbon detection by such techniques cannot be properly achieved. In addition, restricted diffusion phenomena recognized in these intervals, constitute further complications in fluid typing since its presence have similar response than native oil. To address this problem, a fluid characterization method using NMR Diffusion-Editing techniques and processing/interpretation with D-T2 maps in a suite of NMR measurements was applied. The technique allowed the detection and evaluation of restricted diffusion in these reservoirs, enabling better hydrocarbon characterization in a broad viscosity range (from light to heavy). The method also improved the petrophysical evaluation because restricted diffusion is related to tortuosity in the reservoir. Since the application of this innovative reservoir evaluation method, fluid prognosis vs well completion results was increased from around 68% to around 88% in Golfo San Jorge basin. Moreover, in some of these areas rates above 95% were recently achieved in 2004. (author)

  10. Lake-level variations and tides in Lago Argentino, Patagonia: insights from pressure tide gauge records

    Directory of Open Access Journals (Sweden)

    Andreas Richter

    2015-08-01

    Full Text Available Based on precise pressure tide gauge observations lake-level records are derived for two sites in Lago Argentino, southern Patagonia, of 2.5 and 1 years of duration. Applying the tools of time series analysis, the principal processes affecting the lake level are identified and quantified. Lake-level changes reflecting variations in lake volume are dominated by a seasonal cycle of 1.2 m in amplitude. Lake-volume changes occur in addition with a daily period in response to melt water influx from surrounding glaciers. Sporadic lake-volume jumps are caused by bursting of the ice dam of Perito Moreno glacier. Water movements in Lago Argentino are dominated by surface seiches reaching 20 cm in amplitude. Lake tides reach a maximum amplitude of 3 mm. The comparison of the tidal signal extracted from the lake-level observations with a model composed of the contributions of body tide and ocean tidal loading indicates a phase shift of 23° which is most likely explained by an 1 hour phase lag of global ocean tide models in the region of the highly fragmented Pacific coast. The comparison of the obtained results with those of a previous study of Lago Fagnano, Tierra del Fuego, allows to relate differences in the hydrological and hydrodynamic processes between both lakes to morphological properties. This leads to a tentative prediction of the lake-level variability to be expected from other great Patagonian lakes. The presented geodetic results shall serve as a starting point for a detailed limnological investigation of these aquatic ecosystems.

  11. INCORPORACIÓN DEL PAISAJE EN LA GESTIÓN DEL TERRITORIO DE LA PATAGONIA CHILENA

    Directory of Open Access Journals (Sweden)

    MARÍA DOLORES MUÑOZ

    2014-01-01

    Full Text Available Este artículo presenta una metodología para el análisis y gestión del paisaje en la Patagonia chilena, un territorio que se destaca por la belleza y diversidad de los paisajes del agua generados por la presencia de grandes lagos, ríos, fiordos, humedales y campos de hielo. El primer caso de estudio es una investigación para evaluar las potencialidades turísticas y territoriales de los paisajes del agua en la cuenca del río Baker. Se utiliza una metodología interdisciplinaria y técnicas de medición, cualitativa y cuantitativa, que permitieran analizar los valores espaciales, ambientales, territoriales y culturales asociados al paisaje. Un aspecto esencial fue incorporar la valoración social del paisaje. El segundo caso, ubicado en el estrecho de Magallanes, corresponde a una metodología de análisis territorial como base para diseñar un Plan de Manejo Turístico en el Área Marina Protegida Francisco Coloane (que incluye al Parque Marino Francisco Coloane. Comprende el análisis de las condiciones ambientales, las características del paisaje y potencialidades del turismo de intereses especiales asociado al paisaje para respaldar la propuesta de gestión. En ambos casos, la metodología considera al paisaje como principal recurso territorial y plantea una forma de gestión respaldada por principios de sustentabilidad ambiental y social.

  12. An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina

    Science.gov (United States)

    Apesteguía, Sebastián; Smith, Nathan D.; Juárez Valieri, Rubén; Makovicky, Peter J.

    2016-01-01

    Background Late Cretaceous terrestrial strata of the Neuquén Basin, northern Patagonia, Argentina have yielded a rich fauna of dinosaurs and other vertebrates. The diversity of saurischian dinosaurs is particularly high, especially in the late Cenomanian-early Turonian Huincul Formation, which has yielded specimens of rebacchisaurid and titanosaurian sauropods, and abelisaurid and carcharodontosaurid theropods. Continued sampling is adding to the known vertebrate diversity of this unit. Methodology/ Principal Findings A new, partially articulated mid-sized theropod was found in rocks from the Huincul Formation. It exhibits a unique combination of traits that distinguish it from other known theropods justifying erection of a new taxon, Gualicho shinyae gen. et sp. nov. Gualicho possesses a didactyl manus with the third digit reduced to a metacarpal splint reminiscent of tyrannosaurids, but both phylogenetic and multivariate analyses indicate that didactyly is convergent in these groups. Derived characters of the scapula, femur, and fibula supports the new theropod as the sister taxon of the nearly coeval African theropod Deltadromeus and as a neovenatorid carcharodontosaurian. A number of these features are independently present in ceratosaurs, and Gualicho exhibits an unusual mosaic of ceratosaurian and tetanuran synapomorphies distributed throughout the skeleton. Conclusions/ Significance Gualicho shinyae gen. et sp. nov. increases the known theropod diversity of the Huincul Formation and also represents the first likely neovenatorid from this unit. It is the most basal tetatanuran to exhibit common patterns of digit III reduction that evolved independently in a number of other tetanuran lineages. A close relationship with Deltadromaeus from the Kem Kem beds of Niger adds to the already considerable biogeographic similarity between the Huincul Formation and coeval rock units in North Africa. PMID:27410683

  13. Centennial and millennial-scale hydroclimate changes in northwestern Patagonia since 16,000 yr BP

    Science.gov (United States)

    Moreno, Patricio I.; Videla, Javiera

    2016-10-01

    We examine hydroclimate changes at centennial/millennial timescales since 16,000 yr BP in northwestern Patagonia based on the pollen and charcoal record from Lago El Salto, a small closed-basin lake located in the Chilean Lake District (41°38‧48.02″S, 73° 5‧48.42″W). We observe cold/wet conditions between 14,500-16,000 yr BP, followed by further cooling with increased precipitation until 13,000 yr BP, enhanced precipitation seasonality and/or variability between 11,600-13,000 yr BP, and an extended warm-and-dry interval between 7600 and 11,300 yr BP with peak paleofire activity. Colder-and-wetter than present conditions and muted paleofire activity prevail between 5300 and 7600 yr BP, followed by alternating cold/wet and centennial-scale warm/dry phases starting at 5300 yr BP with three conspicuous megadroughts since 2500 yr BP. The most recent megadrought occurred during the Medieval Climate Anomaly. We identify a cold reversal that spans the Antarctic Cold Reversal (ACR) and the Younger Dryas (YD) chrons with stronger-than-present westerly influence during the former and enhanced variability during the latter. These results extend the northern limit of strong cooling and increase in precipitation during the ACR and the southern limit of influence of strong hydrologic variations during the YD in terrestrial environments, suggesting an overlap in the spheres of influence of processes originating from southern and northern polar latitudes. An extended warm southern westerly wind (SWW)-minimum interval is evident between 7600 and 11,300 yr BP, followed by a rapid shift to cool-moist conditions between 5300 and 7600 yr BP brought by a mid-Holocene SWW maximum. Since then we observe centennial-scale hydroclimate variability, which has driven biodiversity and fire-regime shifts of evergreen temperate rainforests.

  14. Tectonic events reflected by palaeocurrents, zircon geochronology, and palaeobotany in the Sierra Baguales of Chilean Patagonia

    Science.gov (United States)

    Gutiérrez, Nestor M.; Le Roux, Jacobus P.; Vásquez, Ana; Carreño, Catalina; Pedroza, Viviana; Araos, José; Oyarzún, José Luis; Pablo Pino, J.; Rivera, Huber A.; Hinojosa, L. F.

    2017-01-01

    The Sierra Baguales, situated north of the Torres Del Paine National Park in the Magallanes region of southern Chile, shows a well-exposed stratigraphic sequence ranging from the Late Cretaceous to late Pliocene, which presents a unique opportunity to study the evolution of sedimentological styles and trends, palaeoclimate changes, and tectonic events during this period. The depositional environment changed from a continental slope and shelf during the Cenomanian-Campanian (Tres Pasos Formation) to deltaic between the Campanian-Maastrichtian (Dorotea Formation) and estuarine in the Lutetian-Bartonian (Man Aike Formation). During the Rupelian, a continental environment with meandering rivers and overbank marshes was established (Río Leona Formation). This area was flooded in the early Burdigalian (Estancia 25 de Mayo Formation) during the Patagonian Transgression, but emerged again during the late Burdigalian (Santa Cruz Formation). Measured palaeocurrent directions in this Mesozoic-Cenozoic succession indicate source areas situated between the northeast and east-southeast during the Late Cretaceous, east-southeast during the middle Eocene, and southwest during the early Oligocene to early Miocene. This is confirmed by detrital zircon age populations in the different units, which can be linked to probable sources of similar ages in these areas. The east-southeastern provenance is here identified as the Antarctic Peninsula or its northeastern extension, which is postulated to have been attached to Fuegian Patagonia during the Eocene. The southwestern and western sources were exhumed during gradual uplift of the Southern Patagonian Andes, coinciding with a change from marine to continental conditions in the Magallanes-Austral Basin, as well as a decrease in mean annual temperature and precipitation indicated by fossil leaves in the Río Leona Formation. The rain shadow to the east of the Andes thus started to develop here during the late Eocene-early Oligocene ( 34

  15. Validating numerical simulations of snow avalanches using dendrochronology: the Cerro Ventana event in Northern Patagonia, Argentina

    Science.gov (United States)

    Casteller, A.; Christen, M.; Villalba, R.; Martínez, H.; Stöckli, V.; Leiva, J. C.; Bartelt, P.

    2008-05-01

    The damage caused by snow avalanches to property and human lives is underestimated in many regions around the world, especially where this natural hazard remains poorly documented. One such region is the Argentinean Andes, where numerous settlements are threatened almost every winter by large snow avalanches. On 1 September 2002, the largest tragedy in the history of Argentinean mountaineering took place at Cerro Ventana, Northern Patagonia: nine persons were killed and seven others injured by a snow avalanche. In this paper, we combine both numerical modeling and dendrochronological investigations to reconstruct this event. Using information released by local governmental authorities and compiled in the field, the avalanche event was numerically simulated using the avalanche dynamics programs AVAL-1D and RAMMS. Avalanche characteristics, such as extent and date were determined using dendrochronological techniques. Model simulation results were compared with documentary and tree-ring evidences for the 2002 event. Our results show a good agreement between the simulated projection of the avalanche and its reconstructed extent using tree-ring records. Differences between the observed and the simulated avalanche, principally related to the snow height deposition in the run-out zone, are mostly attributed to the low resolution of the digital elevation model used to represent the valley topography. The main contributions of this study are (1) to provide the first calibration of numerical avalanche models for the Patagonian Andes and (2) to highlight the potential of textit{Nothofagus pumilio} tree-ring records to reconstruct past snow-avalanche events in time and space. Future research should focus on testing this combined approach in other forested regions of the Andes.

  16. Environmental Niche Overlap between Common and Dusky Dolphins in North Patagonia, Argentina

    Science.gov (United States)

    Svendsen, Guillermo Martín; Romero, María Alejandra; Williams, Gabriela Noemí; Gagliardini, Domingo Antonio; Crespo, Enrique Alberto; Dans, Silvana Laura; González, Raúl Alberto

    2015-01-01

    Research on the ecology of sympatric dolphins has increased worldwide in recent decades. However, many dolphin associations such as that between common dolphins (Delphinus delphis) and dusky dolphins (Lagenorhynchus obscurus) are poorly understood. The present study was conducted in the San Matías Gulf (SMG) ecosystem (North Patagonia, Argentina) where a high diet overlap among both species was found. The main objective of the present work was to explore the niche overlap of common and dusky dolphins in the habitat and temporal dimensions. The specific aims were (a) to evaluate the habitat use strategies of both species through a comparison of their group attributes (social composition, size and activity), and (b) to evaluate their habitat preferences and habitat overlap through Environmental Niche modeling considering two oceanographic seasons. To accomplish these aims, we used a historic database of opportunistic and systematic records collected from 1983 to 2011. Common and dusky dolphins exhibited similar patterns of group size (from less than 10 to more than 100 individuals), activity (both species use the area to feed, nurse, and copulate), and composition (adults, juveniles, and mothers with calves were observed for both species). Also, both species were observed travelling and feeding in mixed-species groups. Specific overlap indices were higher for common dolphins than for dusky dolphins, but all indices were low, suggesting that they are mainly segregated in the habitat dimension. In the case of common dolphins, the best habitats were located in the northwest of the gulf far from the coast. In the warm season they prefer areas with temperate sea surface and in the cold season they prefer areas with relatively high variability of sea surface temperature. Meanwhile, dusky dolphins prefer areas with steep slopes close to the coast in the southwestern sector of the gulf in both seasons. PMID:26091542

  17. Environmental Niche Overlap between Common and Dusky Dolphins in North Patagonia, Argentina.

    Directory of Open Access Journals (Sweden)

    Guillermo Martín Svendsen

    Full Text Available Research on the ecology of sympatric dolphins has increased worldwide in recent decades. However, many dolphin associations such as that between common dolphins (Delphinus delphis and dusky dolphins (Lagenorhynchus obscurus are poorly understood. The present study was conducted in the San Matías Gulf (SMG ecosystem (North Patagonia, Argentina where a high diet overlap among both species was found. The main objective of the present work was to explore the niche overlap of common and dusky dolphins in the habitat and temporal dimensions. The specific aims were (a to evaluate the habitat use strategies of both species through a comparison of their group attributes (social composition, size and activity, and (b to evaluate their habitat preferences and habitat overlap through Environmental Niche modeling considering two oceanographic seasons. To accomplish these aims, we used a historic database of opportunistic and systematic records collected from 1983 to 2011. Common and dusky dolphins exhibited similar patterns of group size (from less than 10 to more than 100 individuals, activity (both species use the area to feed, nurse, and copulate, and composition (adults, juveniles, and mothers with calves were observed for both species. Also, both species were observed travelling and feeding in mixed-species groups. Specific overlap indices were higher for common dolphins than for dusky dolphins, but all indices were low, suggesting that they are mainly segregated in the habitat dimension. In the case of common dolphins, the best habitats were located in the northwest of the gulf far from the coast. In the warm season they prefer areas with temperate sea surface and in the cold season they prefer areas with relatively high variability of sea surface temperature. Meanwhile, dusky dolphins prefer areas with steep slopes close to the coast in the southwestern sector of the gulf in both seasons.

  18. Novel aromatic ring-hydroxylating dioxygenase genes from coastal marine sediments of Patagonia

    Directory of Open Access Journals (Sweden)

    Ferrero Marcela A

    2008-03-01

    Full Text Available Abstract Background Polycyclic aromatic hydrocarbons (PAHs, widespread pollutants in the marine environment, can produce adverse effects in marine organisms and can be transferred to humans through seafood. Our knowledge of PAH-degrading bacterial populations in the marine environment is still very limited, and mainly originates from studies of cultured bacteria. In this work, genes coding catabolic enzymes from PAH-biodegradation pathways were characterized in coastal sediments of Patagonia with different levels of PAH contamination. Results Genes encoding for the catalytic alpha subunit of aromatic ring-hydroxylating dioxygenases (ARHDs were amplified from intertidal sediment samples using two different primer sets. Products were cloned and screened by restriction fragment length polymorphism analysis. Clones representing each restriction pattern were selected in each library for sequencing. A total of 500 clones were screened in 9 gene libraries, and 193 clones were sequenced. Libraries contained one to five different ARHD gene types, and this number was correlated with the number of PAHs found in the samples above the quantification limit (r = 0.834, p nahAc-like genes, phnAc-like genes as identified in Alcaligenes faecalis AFK2, and phnA1-like genes from marine PAH-degraders from the genus Cycloclasticus. Conclusion These results show the presence of hitherto unidentified ARHD genes in this sub-Antarctic marine environment exposed to anthropogenic contamination. This information can be used to study the geographical distribution and ecological significance of bacterial populations carrying these genes, and to design molecular assays to monitor the progress and effectiveness of remediation technologies.

  19. A Water Resources Management Model to Evaluate Climate Change Impacts in North-Patagonia, Argentina

    Science.gov (United States)

    Bucciarelli, L. F.; Losano, F. T.; Marizza, M.; Cello, P.; Forni, L.; Young, C. A.; Girardin, L. O.; Nadal, G.; Lallana, F.; Godoy, S.; Vallejos, R.

    2014-12-01

    Most recently developed climate scenarios indicate a potential future increase in water stress in the region of Comahue, located in the North-Patagonia, Argentina. This region covers about 140,000 km2 where the Limay River and the Neuquén River converge into the Negro River, constituting the largest integrated basins in Argentina providing various uses of water resources: a) hydropower generation, contributing 15% of the national electricity market; b) fruit-horticultural products for local markets and export; c) human and industrial water supply; d) mining and oil exploitation, including Vaca Muerta, second world largest reserves of shale gas and fourth world largest reserves of shale-oil. The span of multiple jurisdictions and the convergence of various uses of water resources are a challenge for integrated understanding of economically and politically driven resource use activities on the natural system. The impacts of climate change on the system could lead to water resource conflicts between the different political actors and stakeholders. This paper presents the results of a hydrological simulation of the Limay river and Neuquén river basins using WEAP (Water Evaluation and Planning) considering the operation of artificial reservoirs located downstream at a monthly time step. This study aims to support policy makers via integrated tools for water-energy planning under climate uncertainties, and to facilitate the formulation of water policy-related actions for future water stress adaptation. The value of the integrated resource use model is that it can support local policy makers understand the implications of resource use trade-offs under a changing climate: 1) water availability to meet future growing demand for irrigated areas; 2) water supply for hydropower production; 3) increasing demand of water for mining and extraction of unconventional oil; 4) potential resource use conflicts and impacts on vulnerable populations.

  20. Oxidation state of Paleozoic subcontinental lithospheric mantle below the Pali Aike volcanic field in southernmost Patagonia

    Science.gov (United States)

    Wang, Jian; Hattori, Keiko H.; Li, Jianping; Stern, Charles R.

    2008-09-01

    Mantle xenoliths in the Quaternary Pali Aike alkaline basalts of southernmost Patagonia include lherzolites and harzburgites with and without garnet. The values of fO 2 for all xenoliths range from 0.33 logarithmic unit below the fayalite-magnetite-quartz buffer (FMQ - 0.33) to FMQ + 0.75, which overlap those for abyssal peridotites. The fO 2 data, together with the bulk rock and mineral compositions, suggest that the subcontinental lithospheric mantle (SCLM) below Pali Aike formed through the accretion of oceanic lithosphere. The oceanic accretion likely occurred in mid to late Paleozoic time when the southern Patagonian terrane formed along the southwest margin of Gondwana. Relict spinel inclusions in garnet suggest that garnet-facies peridotites formed from spinel-facies peridotites most likely in response to pressure increase during the accretion. Comparable fO 2 for garnet- and spinel-facies peridotites suggests that this spinel-garnet transformation was not accompanied by changes in fO 2. Metasomatism by asthenosphere-derived melt through a slab window resulted in the formation of Ti-bearing minerals, and lowering of Mg and enrichment of Ti in bulk rocks and minerals. The replacement of olivine by orthopyroxene formed orthopyroxenites in extreme cases. No significant change in fO 2 is associated with this metasomatism since similar oxidation state is observed between un-metasomatized (FMQ - 0.23 to + 0.48) and metasomatized (FMQ - 0.33 to + 0.75) samples. This is explained by the fO 2 of the asthenospheric melt (~ FMQ - 0.50) similar to the SCLM prior to the metasomatism.

  1. Extracción y clasificación automatizada para la Unidad de Vigilancia Tecnológica e Inteligencia Competitiva de la Patagonia

    OpenAIRE

    2016-01-01

    El presente trabajo presenta la constitución, desarrollo y actividades realizadas por la Unidad de Vigilancia Tecnológica e Inteligencia Competitiva de la Patagonia. En particular el desarrollo realizado de una herramienta que permite automatizar y homogeneizar las ecuaciones de búsqueda que utilizarán los expertos de la Unidad de Vigilancia.

  2. Checklist of the Discomycetes (Fungi of Patagonia, Tierra del Fuego and adjacent antarctic areas

    Directory of Open Access Journals (Sweden)

    Irma J. Gamundí

    2004-01-01

    Full Text Available La información brindada en este catálogo consiste en registrar las especies de hongos pertenecientes a los órdenes Cyttariales, Helotiales, Ostropales, Pezizales, Rhytismatales y Thelebolales (Discomycetes coleccionadas en Patagonia, Tierra del Fuego y áreas adyacentes antárticas (Patagonia. Además datos sobre sus organismos asociados fueron localizados, resumidos, validados y editados. Las fuentes de información fueron las exsiccatae depositadas en colecciones de Argentina y otros países y de las publicaciones listadas en la bibliografía. Otros registros derivaron de observaciones de campo sobre material fresco y colecciones de referencia. La información fue acumulada en un sistema computarizado relacional de datos taxonómicos, nomenclaturales, bibliográficos, de distribución geográfica y de observaciones biológicas. Este sistema permite la acumulación de datos paralelos en diferentes idiomas, y distingue la información original de la opinión corriente de lo que puede significar esa información. En la Biological Records Database, 5029 registros fueron creados para observaciones sobre la ocurrencia temporal y espacial de los organismos vivos de la región. De éstos, 2613 corresponden a registros de colecciones de Discomycetes de la Patagonia y Tierra del Fuego, con la siguiente distribución: 1854 para a la Argentina, 687 para Chile y 72 para áreas adyacentes antárticas. Excluyendo los sinónimos, los Discomycetes están representados por 361 especies y taxones subespecíficos (160 géneros, 22 familias y 7 órdenes. Los registros remanentes fueron de organismos asociados con los Discomycetes: 163 animales (8 especies, 8 géneros, 6 familias y 5 órdenes; 2 Chromista; 223 hongos (52 especies, 54 géneros, 26 familias y 13 ódenes; 2028 plantas (159 especies, 122 géneros, 59 familias y 39 órdenes. Cada uno de estos taxones (y cada sinónimo conocido está representado por un registro separado en la Base de Datos Taxon

  3. Little ice age advance and retreat of Glaciar Jorge Montt, Chilean Patagonia, recorded in maps, air photographs and dendrochronology

    Directory of Open Access Journals (Sweden)

    A. Rivera

    2011-10-01

    Full Text Available Glaciar Jorge Montt (48°20' S/73°30' W, one of the main tidewater glaciers of the Southern Patagonian Icefield (SPI, has experienced the fastest frontal retreat observed in Patagonia during the past century, with a recession of 19.5 km between 1898 and 2011. This record retreat uncovered trees overridden during the Little Ice Age (LIA advance of the glacier. Samples of these trees were dated using radiocarbon methods, yielding burial ages between 460 and 250 cal yr BP. The dendrochronology and maps indicate that Glaciar Jorge Montt was at its present position before the beginning of the LIA, in concert with several other glaciers in Southern Patagonia, and reached its maximum advance position between 1650 and 1750 AD. The post-LIA retreat is most likely triggered by climatically induced changes during the 20th century, however, Glaciar Jorge Montt has responded more dramatically than its neighbours. The retreat of Jorge Montt opened a new fjord 19.5 km long, and up to 391 m deep, with a varied bathymetry well correlated with glacier retreat rates, suggesting that dynamic responses of the glacier are at least partially connected to near buoyancy conditions at the ice front, resulting in high calving fluxes, accelerating thinning rates and rapid ice velocities.

  4. Hb Wilde and Hb Patagonia: two novel elongated beta-globin variants causing dominant beta-thalassemia.

    Science.gov (United States)

    Scheps, Karen G; Hasenahuer, Marcia A; Parisi, Gustavo; Fornasari, María S; Pennesi, Sandra P; Erramouspe, Beatriz; Basack, Felisa N; Veber, Ernesto S; Aversa, Luis; Elena, Graciela; Varela, Viviana

    2015-06-01

    We describe here the molecular and hematological characteristics of novel frameshift mutations in exon 2 of the HBB gene (in heterozygous state) found in two Argentinean pediatric patients with dominant β-thalassemia-like features. In Hb Wilde, HBB:c.270_273delTGAG(p.Glu90Cysfs*67), we detected the deletion of the third base of the codon 89 (T) and the codon 90 (GAG), whereas in Hb Patagonia, HBB:c.296_297dupGT(p.Asp99Trpfs*59), the frameshift mutation was due to a duplication of a 'GT' dinucleotide after the second base of codon 98 (GTG). The Hb Patagonia and Hb Wilde mutations would result in elongated β-globin chains with modified C-terminal sequences and a total of 155 and 157 amino acids residues, respectively. Based on bioinformatics and structural analysis, as well as protein modeling, we predict that the elongated β-globins would affect the formation of the αβ dimers and their stability, which would further support the mechanism for the observed clinical features in both patients.

  5. Cerro Bombero: registro de Hippidion saldiasi Roth, 1899 (Equidae, Perissodactyla en el Holoceno temprano de Patagonia (Santa Cruz, Argentina

    Directory of Open Access Journals (Sweden)

    Alberdi, M. T.

    2008-06-01

    Full Text Available A new record of Hippidion saldiasi with new radiocarbon data referred to early Holocene (8,850 ± 80 year C-14 B.P of Patagonia is reported. Both its peculiar geographic location in a scarcely prospected zone and its radiocarbon age, provide new elements to discuss the previous hypotheses about the extinction of the horses and its relations with the human beings that inhabited the different environments of South America.Presentamos un nuevo registro de Hippidion saldiasi con datación radiocarbónica directa correspondiente al Holoceno temprano de Patagonia (8.850 ± 80 años C-14 AP. Su particular ubicación temporal y geográfica en una zona poco estudiada hasta ahora y su registro reciente, aportan nuevos elementos para discutir las hipótesis previas sobre la extinción de los caballos y su relación con los grupos humanos que colonizaron los diferentes ambientes de América del Sur.

  6. Liver fluke (Fasciola hepatica) naturally infecting introduced European brown hare (Lepus europaeus) in northern Patagonia: phenotype, prevalence and potential risk.

    Science.gov (United States)

    Cuervo, Pablo F; Cataldo, Sophia Di; Fantozzi, M Cecilia; Deis, Erika; Isenrath, Gabriela Diaz; Viberti, Gabriela; Artigas, Patricio; Peixoto, Raquel; Valero, M Adela; Sierra, Roberto Mera Y; Mas-Coma, Santiago

    2015-09-01

    Fascioliasis has recently been included in the WHO list of Neglected Zoonotic Diseases. Besides being a major veterinary health problem, fascioliasis has large underdeveloping effects on the human communities affected. Though scarcely considered in fascioliasis epidemiology, it is well recognized that both native and introduced wildlife species may play a significant role as reservoirs of the disease. The objectives are to study the morphological characteristics of Fasciola hepatica adults and eggs in a population of Lepus europaeus, to assess liver fluke prevalence, and to analyze the potential reservoir role of the European brown hare in northern Patagonia, Argentina, where fascioliasis is endemic. Measures of F. hepatica found in L. europaeus from northern Patagonia demonstrate that the liver fluke is able to fully develop in wild hares and to shed normal eggs through their faeces. Egg shedding to the environment is close to the lower limit obtained for pigs, a domestic animal whose epidemiological importance in endemic areas has already been highlighted. The former, combined with the high prevalence found (14.28%), suggest an even more important role in the transmission cycle than previously considered. The results obtained do not only remark the extraordinary plasticity and adaptability of this trematode species to different host species, but also highlight the role of the European brown hare, and other NIS, as reservoirs capable for parasite spillback to domestic and native cycle, representing a potentially important, but hitherto neglected, cause of disease emergence.

  7. Sistemas de Conversores Fluidodinámicos de Energías Alternativas para la Patagonia Argentina

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    Carlos Labriola

    2016-12-01

    Full Text Available La UNPA-UACO comenzó a estudiar el tema de Energía Oceánica y sus conversores con el PI 29 B 125 del 2010: “Análisis de Sistemas de Conversores Fluidodinámicos de Energía Renovable para la Patagonia Austral de Argentina”. Luego en el 2014 se comienza el PI 29 B 163: “Sistemas Conversores Fluido-dinámicos de Energía Renovable para la Patagonia, Argentina”. Este proyecto analiza los recursos oceánicos de las corrientes marinas y undimotriz a macroescala y además se utilizaran modelos desarrollados de conversores de energía de las corrientes marinas y de las olas para estudio y posterior dimensionamiento de prototipos de aplicación para dichas fuentes. Durante el 2014 el becario se propone para estudiar el recurso de las mareas en Río Gallegos y determinación de ubicación de un futuro prototipo en la Ría de Rio Gallegos. El presente informe detalla el trabajo desarrollado durante el 2015 en lo que respecta a estudio del recurso mareomotriz y posible localización de prototipo de turbina hidrocinética flotante para la Ría de Río Gallegos, santa Cruz, Argentina.

  8. El cambio climático global en la Patagonia desde el viaje de Charles Darwin hasta nuestros días The global climatic change in Patagonia and Tierra del Fuego since voyage of Charles Darwin until present times

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    Jorge Rabassa

    2010-08-01

    Full Text Available El viaje del Beagle que trajo a Charles Darwin a América del Sur entre 1832 y 1835 AD y en particular, al territorio argentino, se desarrolló bajo condiciones climáticas muy desfavorables: frías, secas y ventosas, correspondientes a las condiciones predominantes en la última fase de la pequeña edad del hielo, un episodio frío global que caracterizó a los siglos XVII, XVIII y XIX. Esta fase es conocida como mínimo de Dalton, en referencia a la disminución relativa de la frecuencia de las manchas solares, lo cual redunda en una disminución de la radiación solar y como consecuencia, en menores temperaturas medias globales en ese período. Darwin fue perfectamente consciente de dichas condiciones climáticas, que se manifestaban fuertemente en Europa, en particular en los Alpes, y así lo transmite en sus escritos. Desde el viaje de Darwin a la Patagonia, las condiciones climáticas y ambientales cambiaron sustancialmente, especialmente luego de 1850 AD y, finalmente, después de mediados de la década de 1970 AD. Algunas de las más importantes consecuencias del cambio climático global son el aumento de la temperatura media anual o la temperatura estacional, la elevación o disminución de las precipitaciones al nivel regional, el continuo ascenso global del nivel del mar y un incremento significativo de la frecuencia de eventos meteorológicos extremos. El impacto de esos cambios ha sido observado en los glaciares de Patagonia y Tierra del Fuego, por lo menos desde 1978 AD, y particularmente en la última década del siglo XX. Los impactos más notables son la rápida recesión de las márgenes del hielo en los glaciares, el adelgazamiento de la cobertura glacial, la elevación de la línea de nieve regional y la reducción de las áreas andinas bajo condiciones de suelos permanentemente congelados (permafrost, como han demostrado estudios científicos recientes. A la tasa presente de recesión del hielo glacial, la mayoría, si no

  9. La fertilidad química del suelo y el «mal del ciprés» en Patagonia, Argentina Soil chemical fertility and austrocedrus chilensis disease in Patagonia, Argentina

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    Daniela Morales

    2011-12-01

    Full Text Available Los bosques de Austrocedrus chilensis sufren un proceso de mortalidad conocido como «mal del ciprés», cuya causa es aún discutida. Estudios previos sugieren la presencia de Phytophthora austrocedrae como agente causal de la mortalidad; sin embargo, el origen de la enfermedad continúa en estudio, dado que existen áreas afectadas no vinculadas con Phytophthora. El suelo, principalmente a través de sus características físicas y morfológicas, fue evidenciado como un factor asociado con la aparición y desarrollo de la enfermedad. En este trabajo, se evaluó la fertilidad química del suelo en relación al «mal del ciprés». Se seleccionaron cuatro sectores ubicados en el Valle «16 de Octubre» de la provincia del Chubut correspondientes a bosques puros y densos de A. chilensis. En cada sector se instalaron parcelas en áreas del bosque con síntomas severos de la enfermedad y en áreas sin síntomas. A su vez se incorporaron al estudio ocho parcelas control, ubicadas en bosques completamente sanos. Se tomaron muestras del horizonte A y se caracterizaron las propiedades químicas del suelo. No se encontraron deficiencias nutricionales y se observó un buen estado nutricional en todos los suelos analizados, aún en los bosques afectados, reflejándose en valores adecuados de materia orgánica, nitrógeno, bases y capacidad de intercambio catiónico. Se manifestaron diferencias entre los suelos bajo bosque afectado y suelos bajo bosques control en los contenidos de suma de bases, saturación de bases, calcio, pH NaF y fósforo. Estas diferencias podrían estar asociadas tanto a las condiciones de drenaje como a la presencia de Phytophthora.Austrocedrus chilensis forests suffer a widespread mortality locally known as «mal del ciprés» (cypress disease whose cause remains controversial. Previous studies suggested Phytophthora austrocedrae as the biotic cause; however, the origin of the mortality is still being studied since there are

  10. Ignition probability of fine dead surface fuels in native Patagonia forests of Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, L.; Defosse, G. E.

    2014-06-01

    Aim of study: The Canadian Forest Fire Weather Index (FWI) is being implemented all over the world. This index is being adapted to the Argentinean ecosystems since the year 2000. With the objective of calibrating the Fine Fuel Moisture Code (FFMC) of the FWI system to Patagonian forests, we studied the relationship between ignition probability and fine dead surface fuel moisture content (MC) as an indicator of potential fire ignition. Area of study: The study area is located in northwestern Patagonia, Argentina, and comprised two main forest types (cypress and nire) grown under a Mediterranean climate, with a dry summer and precipitations during winter and autumn ({approx}500-800 mm per year). Material and methods: We conducted lab ignition tests fires to determine the threshold of fine dead fuel ignition at different MC levels. Moisture content of dead fine surface fuels in the field was measured every 10-15 days from November to March for three seasons. We calculated the FFMC during these seasons and correlated it with the measured MC by applying a logistic regression model. We combined the results of the ignition tests and of the regressions to suggest FFMC categories for estimating fire danger in Patagonian forests. Main results: The ignition threshold occurred at MC values of 21.5 and 25.0% for cypress and nire sites, respectively. The MC measured varied from 7.3 to 129.6%, and the calculated FFMC varied between 13.4 and 92.6. Highly significant regressions resulted when FFMC was related to MC. The ignition threshold corresponded to a FFMC = 85. We proposed to divide the FFMC scale in three fire danger categories: Low (FFMC {<=} 85), High (85 < FFMC{<=}89) and Extreme (FFMC > 89). Research highlights: Our results provide a useful tool for predicting fire danger in these ecosystems, and are a contribution to the development of the Argentinean Fire Danger Rating and a reference for similar studies in other countries where the FWI is being implemented. (Author)

  11. Peat decomposition records in three pristine ombrotrophic bogs in southern Patagonia

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    T. Broder

    2012-04-01

    Full Text Available Ombrotrophic bogs in southern Patagonia have been examined with regard to paleoclimatic and geochemical research questions but knowledge about organic matter decomposition in these bogs is limited. Therefore, we examined peat humification with depth by Fourier Transformed Infrared (FTIR measurements of solid peat, C/N ratio, and δ13C and δ15N isotope measurements in three bog sites. Peat decomposition generally increased with depth but distinct small scale variation occurred, reflecting fluctuations in factors controlling decomposition. C/N ratios varied mostly between 40 and 120 and were significantly correlated (R2 > 0.55, p < 0.01 with FTIR-derived humification indices. The degree of decomposition was lowest at a site presently dominated by Sphagnum mosses. The peat was most strongly decomposed at the driest site, where currently peat-forming vegetation produced less refractory organic material, possibly due to fertilizing effects of high sea spray deposition. Decomposition of peat was also advanced near ash layers, suggesting a stimulation of decomposition by ash deposition. Values of δ13C were 26.5 ± 2‰ in the peat and partly related to decomposition indices, while δ15N in the peat varied around zero and did not consistently relate to any decomposition index. Concentrations of DOM partly related to C/N ratios, partly to FTIR derived indices. They were not conclusively linked to the decomposition degree of the peat. DOM was enriched in 13C and in 15N relative to the solid phase probably due to multiple microbial modifications and recycling of N in these N-poor environments. In summary, the depth profiles of C/N ratios, δ13C values, and FTIR spectra seemed to reflect changes in environmental conditions affecting decomposition, such as bog wetness, but were dominated by site specific factors, and are further influenced by ash

  12. Ice elevation and areal changes of glaciers from the Northern Patagonia Icefield, Chile

    Science.gov (United States)

    Rivera, Andrés; Benham, Toby; Casassa, Gino; Bamber, Jonathan; Dowdeswell, Julian A.

    2007-10-01

    High thinning rates (up to - 4.0 ± 0.97 m a - 1 ) have been measured at Campo de Hielo Patagónico Norte (CHN) or Northern Patagonia Icefield, Chile between 1975 and 2001. Results have been obtained by comparing a Digital Elevation Model (DEM) derived from regular cartography compiled by Instituto Geográfico Militar of Chile (IGM) based upon 1974/1975 aerial photographs and a DEM generated from Advanced Space-borne Thermal Emission and Reflection Radiometer (ASTER) satellite images acquired in September 2001. A complete cloud-free Landsat ETM+ satellite image mosaic acquired in March 2001 was used to update the available glacier inventory of the CHN, including all glaciers larger than 0.5 km 2 (48 new glaciers). A new delineation of ice divides was also performed over the accumulation areas of glaciers sharing the high plateau where the existing regular cartography exhibits poor coverage of topographic information. This updated glacier inventory produced a total ice area for 2001 of 3953 km 2, which represents a decrease of 3.4 ± 1.5% (140 ± 61 km 2 of ice) with respect to the total ice area of the CHN in 1979 calculated from a Landsat MSS satellite image. Almost 62% of the total area change between 1979 and 2001 took place in glaciers located at the western margin of the CHN, where the maximum area loss was experienced by Glaciar San Quintín with 33 km 2. At the southern margin, Glaciar Steffen underwent the largest ice-area loss (12 km 2 or 2.6% of the 1979 area), whilst at the eastern margin the greatest area loss took place in Glaciares Nef (7.9 km 2, 5.7% of the 1979 area) and Colonia (9.1 km 2, 2.7% of the 1979 area). At the northern margin of the CHN the lower debris-covered ablation area of Glaciar Grosse collapsed into a new freshwater lake formed during the late 1990s. The areal changes measured at the CHN are much larger than previously estimated due to the inclusion of changes experienced in the accumulation areas. The CHN as a whole is

  13. Sediment records of highly variable mercury inputs to mountain lakes in Patagonia during the past millennium

    Science.gov (United States)

    Ribeiro Guevara, S.; Meili, M.; Rizzo, A.; Daga, R.; Arribére, M.

    2010-04-01

    High Hg levels in the pristine lacustrine ecosystems of the Nahuel Huapi National Park, a protected zone situated in the Andes of Northern Patagonia, Argentina, have initiated further investigations on Hg cycling and source identification. Here we report Hg records in sedimentary sequences to identify atmospheric sources during the past millennium. In addition to global transport and deposition, a potential atmospheric Hg source to be considered is the local emissions associated with volcanic activity, because the Park is situated in the Southern Volcanic Zone. Two sediment cores were extracted from Lake Tonček, a small, high-altitude system reflecting mainly direct inputs associated with atmospheric contributions, and Lake Moreno Oeste, a much larger and deeper lake having an extended watershed covered mostly by native forest. The sedimentary sequences were dated based on both 210Pb and 137Cs profiles. In addition, tephra layers were identified and geochemically characterized for chronological application and to investigate any association of volcanic eruptions with Hg records. Hg concentrations in sediments were measured along with 32 other elements, as well as organic matter, subfossil chironomids, and biogenic silica. Observed background Hg concentrations, determined from the sequence domains with lower values, ranged from 50 to 100 ng g-1 dry weight (DW), whereas the surficial layers reached 200 to 500 ng g-1 DW. In addition to this traditional pattern, however, two deep domains in both sequences showed dramatically increased Hg levels reaching 400 to 650 ng g-1 DW; the upper dated to the 18th to 19th centuries, and the lower around the 13th century. These concentrations are not only elevated in the present profiles but also many-fold above the background values determined in other fresh water sediments, as were also the Hg fluxes, reaching 120 to 150 μg m-2 y-1 in Lake Tonček . No correlation was observed between Hg concentrations and the contents of

  14. Carbonatite metasomatized peridotite xenoliths from southern Patagonia: implications for lithospheric processes and Neogene plateau magmatism

    Science.gov (United States)

    Gorring, Matthew L.; Kay, Suzanne M.

    The mineral chemistry, major and trace element, and Sr-Nd isotopic composition of Cr-diopside, spinel peridotite xenoliths from the Estancia Lote 17 locality in southern Patagonia document a strong carbonatitic metasomatism of the backarc continental lithosphere. The Lote 17 peridotite xenolith suite consists of hydrous spinel lherzolite, wehrlite, and olivine websterite, and anhydrous harzburgite and lherzolite. Two-pyroxene thermometry indicates equilibration temperatures ranging from 870 to 1015°C and the lack of plagioclase or garnet suggests the xenoliths originated from between 40 and 60km depth. All of the xenoliths are LILE- and LREE-enriched, but have relatively low 87Sr/86Sr (0.70294 to 0.70342) and high ɛNd (+3.0 to +6.6), indicating recent trace element enrichment ( 25Ma, based on the low 87Sr/86Sr and high Rb concentrations of phlogopite separates) in the long-term, melt-depleted Patagonian lithosphere. Lote 17 peridotite xenoliths are divided into two basic groups. Group 1 xenoliths consist of fertile peridotites that contain hydrous phases (amphibole+/-phlogopite+/-apatite). Group 1 xenoliths are further subdivided into three groups (a, b, and c) based on distinctive textures and whole-rock chemistry. Group 1 xenolith mineralogy and chemistry are consistent with a complex metasomatic history involving variable extents of recent carbonatite metasomatism (high Ca/Al, Nb/La, Zr/Hf, low Ti/Eu) that has overprinted earlier metasomatic events. Group 2 xenoliths consist of infertile, anhydrous harzburgites and record cryptic metasomatism that is attributed to CO2-rich fluids liberated from Group 1 carbonatite metasomatic reactions. Extremely variable incompatible trace element ratios and depleted Sr-Nd isotopic compositions of Lote 17 peridotite xenoliths indicate that the continental lithosphere was neither the primary source nor an enriched lithospheric contaminant for Neogene Patagonian plateau lavas. Neogene plateau magmatism associated with formation

  15. A new peat bog testate amoeba transfer function and quantitative palaeohydrological reconstructions from southern Patagonia

    Science.gov (United States)

    van Bellen, S.; Mauquoy, D.; Payne, R.; Roland, T. P.; Hughes, P. D.; Daley, T. J.; Street-Perrot, F. A.; Loader, N.

    2013-12-01

    Testate amoebae have been used extensively as proxies for environmental change and palaeoclimate reconstructions in European and North American peatlands. The presence of these micro-organisms in surface samples is generally significantly linked to the local water table depth (WTD) and preservation of the amoeba shells downcore allows for millennial length water table reconstructions. Peat bog archive records in southern Patagonia are increasingly the focus of palaeoecological research due to the possibility of detecting changes in the Southern Westerlies. These Sphagnum magellanicum-dominated peat bogs are characterised by a wide range of water table depths, from wet hollows to high hummocks (>100 cm above the water table). Here we present the first transfer function for this region along with ~2k-year palaeorecords from local peat bogs. A modern dataset (155 samples) was sampled along transects from five bogs in 2012 and 2013. Measurements of WTD, pH and conductivity were taken for all samples. The transfer function model was based on the 2012 dataset, while the 2013 samples served as an independent test set to validate the model. Besides the standard leave-one-out cross-validation, we applied leave-one-site-out and leave-one transect-out cross-validation, which are effective means of verifying the degree of clustering in the dataset. To ensure that the environmental gradient had been evenly sampled we quantified the root-mean-squared error of prediction (RMSEP) individually for segments of this gradient. Ordinations showed a clear hydrological gradient in amoeba assemblages, with the dominant Assulina muscorum at the dry end and Amphitrema wrightianum and Difflugia globulosa at the wet end. Canonical correspondence analysis showed that WTD was the most important environmental variable, accounting for 18% of the variance in amoeba assemblages. A weighted averaging-partial least squares model showed best performance in cross-validation, using the 2013 data as an

  16. Nacionalismo territorialista en textos escolares: representaciones de la Patagonia en la dictadura militar argentina (1966-1983 Territorialist nationalism in school textbooks: representations of Patagonia in Argentinian military dictatorship (1966-1983

    Directory of Open Access Journals (Sweden)

    Jesús Jaramillo

    2012-03-01

    Full Text Available Los textos escolares desde hace tiempo se han constituido en una de las fuentes primarias para el campo de la Historia de la Educación en tanto son instrumentos de socialización formal básica. Sea considerado registro escrito editorial, herramienta didáctica o registro de memoria escolar, los textos escolares instituyen - y, en ocasiones, eternizan - concepciones e intereses reflejados en sus contenidos "oficiales". Investigaciones recientes en la búsqueda de la realidad escolar han enfatizado la importancia de los mismos en la construcción de las identidades nacionales, pero también de las identidades de grupos socio-culturales, socio-étnicos y regionales. Este artículo, a partir de una indagación historiográfica sobre libros de lectura, intenta reconstruir las diferentes tramas discursivas textuales e iconográficas en que ha sido representada la Patagonia durante los periodos dictatoriales argentinos 1966-1973 y 1976-1983, en escuelas primarias de Río Negro y Neuquén. En principio, puede advertirse un conjunto de relatos de la Patagonia y sus habitantes sobre la base de tres núcleos de sentido: el de territorio indígena, desierto e inculto; el de promisión para el progreso y el turismo; y el de soberanía nacional. A través de sus argumentos daremos cuenta que los libros escolares de edición nacional con rasgos eminentemente políticos pero también étnicos y raciales fueron medios de formación y, sobre todo, dispositivos que coadyuvaron a la conformación de una línea ideológica, política y pedagógica propia del nacionalismo católico militar.School textbooks have long been taken as one of the primary sources for the field of the History of Education, since they are instruments of basic formal socializing. Either as editorial written records, as didactic tools, or as records of school memory, school textbooks institute - and sometimes crystallize - conceptions and interests reflected in their "official" contents

  17. Distribución del ictioplancton en la Patagonia austral de Chile: potenciales efectos del deshielo de Campos de Hielo Sur Ichthyoplankton distribution in South Patagonia, Chile: potential effects of ice melting from the Southern Ice Field

    Directory of Open Access Journals (Sweden)

    Mauricio F Landaeta

    2011-07-01

    Full Text Available Durante octubre-noviembre de 2009 se realizó un crucero oceanográfico entre 50 y 53°S de Chile austral, en las cercanías del glaciar Campos de Hielo Sur. Las estaciones cercanas al glaciar presentaron baja temperatura (1-3°C y salinidad ( 0,1 ciclos s-1. Los principales taxa del ictioplancton fueron huevos y larvas de sardina fueguina Sprattus fuegensis, pez hacha Maurolicus parvipinnis, Macrouridae y merluza austral Merluccius australis. El desove principal de S. fuegensis (~ 8000 huevos 10 m-2 ocurrió en zonas mezcladas de la plataforma continental adyacente, mientras que el desove de M. parvipinnis ocurrió en canales intermedios asociado a valores intermedios de estabilidad (N~0,06 ciclos s-1. Se observó una nula o baja abundancia de huevos y larvas de peces en las cercanías del glaciar, y la abundancia de huevos de M. parvipinnis estuvo relacionada positivamente con la temperatura y salinidad de la columna de agua y negativamente con la estabilidad de la columna de agua. Además, hubo una relación negativa entre la densidad del agua de mar y el diámetro de los huevos de S. fuegensis. La relación entre deshielo e ictioplancton podría tener consecuencias en el transporte advectivo y mortalidad masiva de huevos y larvas de peces y el acople pelágico-bentónico en la Patagonia austral de Chile. Como el cambio climático global ha incrementado los deshielos de glaciares en latitudes altas, y el aumento del ingreso de aguas de baja temperatura y salinidad podría tener consecuencias en el ictioplancton de la Patagonia chilena.In October-November 2009, an oceanographic survey was carried out between 50 and 53°S off southern Chile, near the Southern Ice Field. The stations near the glacier showed low temperatures (1-3°C and salinity ( 0.1 cycles s-1. Main ichthyoplankton taxa were eggs and larvae of southern sprat Sprattus fuegensis, lightfish Maurolicus parvipinnis, Macrouridae, and southern hake Merluccius australis. The main

  18. Geología y geoquímica de los cuerpos básicos alcalinos al sur de los lagos Musters y Colhué Huapí, cuenca del golfo San Sorge, Chubut

    Directory of Open Access Journals (Sweden)

    Nilda D Menegatti

    2014-12-01

    Full Text Available En la región de los lagos Colhué Huapí y Musters, situada en la sierra de San Bernardo en el centro sur de la provincia del Chubut, afloran cuerpos ígneos básicos de carácter alcalino con estructuras de stocks, sills, lopolitos y diques, con edades comprendidas entre el Eoceno y Pleistoceno. En este trabajo, se presentan los resultados obtenidos del estudio efectuado en los cerros Negro, Cresta-Puricelli, Guacho, Solo, San Bernardo, Cresta-Trompete y Los Leones-Tumba del Indio, todos ellos localizados al sur de la localidad de Sarmiento. La litología identificada corresponde a gabro, monzogabro nefelínico, sienita nefelínica, basalto y basanita, siendo el gabro la variedad predominante. De acuerdo a la forma, el tamaño, los gradientes texturales y la presencia de zeolitas que presentan los cuerpos intrusivos, se considera que éstos se emplazaron en niveles corticales altos (<1 km. La mayoría de las rocas analizadas son básicas con un porcentaje de SiO2 entre 44 y 48 %, y se caracterizan por el alto contenido en Fe2O3 (10,66-14,67 %, TiO2 (1,23-3,37 % y álcalis (3,35-5,91 %. Los diagramas normalizados tienen el diseño típico de basaltos alcalinos de intraplaca, compatibles con una fuente de tipo OIB enriquecida en elementos incompatibles, con residuo granatífero en la fuente y ausencia de contaminación con la placa subducida o cortical. La pendiente pronunciada de la curva normalizada de REE (La/Yb = 10,2-22,4 señala relativamente bajos grados de fusión parcial. A partir del análisis estructural se plantea un ambiente extensional para el emplazamiento de estos cuerpos que es coherente con lo que indican las características geoquímicas.

  19. Los niveles glauconíticos de la Formación Salamanca, Chubut: su efectividad agronómica como fuente alternativa de fertilizante potásico

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    Liliana N Castro

    2010-05-01

    Full Text Available Las secuencias marinas del Maastrichtiano-Paleoceno inferior representadas por la Formación Salamanca y unidades equivalentes, presentan niveles con glauconita que podrían suplir parcialmente las importaciones de potasio para uso en la industria de fertilizantes. La prospección y muestreo se realizó en las nacientes del río Chico, Chubut, donde los espesores de los niveles glauconíticos alcanzan 20 metros. El trabajo se dividió en fases: fase 1, prospección, muestreo y análisis sedimentológicos y químicos de rutina; fase 2a, ensayos de concentración y tratamiento, y fase 2b, ensayos agronómicos donde se compara la efectividad agronómica de las areniscas glauconíticas (GL con el fertilizante potásico tradicional (KCl. Estos últimos se realizaron en cámara de cultivo, con las fracciones 125 μm y 250 μm, (2,85 y 2,82 % K2O respectivamente de GL y con KCl, variando las dosis aplicadas, más una muestra testigo resultando en total 7 tratamientos. A lo largo de las 4 cosechas no se observó un comportamiento diferencial significativo entre GL1, GL2 (125 y el testigo. Ambos tratamientos de GL 250 μm presentaron una mayor biomasa acumulada, superando al testigo en un 44 y 60 % respectivamente. Como conclusión, los tratamientos con GL (125 presentaron resultados poco diferenciables del testigo, en tanto que en GL (250 los valores alcanzados superaron a los obtenidos con la fertilización con KCl. Probablemente la mayor participación de feldespato potásico junto a un incremento en la velocidad de lixiviación por riego en la fracción 125 μξm origine el rendimiento diferencial observado. La gran extensión areal de la Formación Salamanca y la continuidad de los niveles glauconíticos alienta a continuar su evaluación como fertilizante o enmienda.

  20. Paleoenvironmental reconstruction of the coastal Monte Léon and Santa Cruz formations (Early Miocene) at Rincón del Buque, Southern Patagonia: A revisited locality

    Science.gov (United States)

    Raigemborn, M. Sol; Matheos, Sergio D.; Krapovickas, Verónica; Vizcaíno, Sergio F.; Bargo, M. Susana; Kay, Richard F.; Fernicola, Juan C.; Zapata, Luciano

    2015-07-01

    Sedimentological, ichnological and paleontological analyses of the Early Miocene uppermost Monte León Formation and the lower part of the Santa Cruz Formation were carried out in Rincón del Buque (RDB), a fossiliferous locality north of Río Coyle in Santa Cruz Province, Patagonia, Argentina. This locality is of special importance because it contains the basal contact between the Monte Léon (MLF) and the Santa Cruz (SCF) formations and because it preserves a rich fossil assemblage of marine invertebrates and marine trace fossils, and terrestrial vertebrates and plants, which has not been extensively studied. A ˜90 m-thick section of the MLF and the SCF that crops out at RDB was selected for this study. Eleven facies associations (FA) are described, which are, from base to top: subtidal-intertidal deposits with Crassotrea orbignyi and bioturbation of the Skolithos-Cruziana ichnofacies (FA1); tidal creek deposits with terrestrial fossil mammals and Ophiomorpha isp. burrows (FA2); tidal flat deposits with Glossifungites ichnofacies (FA3); deposits of tidal channels (FA4) and tidal sand flats (FA5) both with and impoverish Skolithos ichnofacies associated; marsh deposits (FA6); tidal point bar deposits recording a depauperate mixture of both the Skolithos and Cruziana ichnofacies (FA7); fluvial channel deposits (FA8); fluvial point bar deposits (FA9); floodplain deposits (FA10); and pyroclastic and volcaniclastic deposits of the floodplain where terrestrial fossil mammal remains occur (FA11). The transition of the MLF-SCF at RDB reflects a changing depositional environment from the outer part of an estuary (FA1) through the central (FA2-6) to inner part of a tide-dominated estuary (FA7). Finally a fluvial system occurs with single channels of relatively low energy and low sinuosity enclosed by a broad, low-energy floodplain dominated by partially edaphized ash-fall, sheet-flood, and overbank deposits (FA8-11). Pyroclastic and volcaniclastic materials throughout the

  1. Epidemiological studies on intestinal helminth parasites of the patagonian grey fox (Pseudalopex griseus) in Tierra del Fuego, Patagonia Argentina.

    Science.gov (United States)

    Zanini, Fabián; Laferrara, Miguel; Bitsch, Matías; Pérez, Héctor; Elissondo, Maria Celina

    2006-03-31

    The present work was performed to study the intestinal helminths of the patagonian grey fox (Pseudalopex griseus) and to obtain information about its possible role in the sylvatic life cycle of Echinococcu granulosus in Tierra del Fuego, Patagonia Argentina. Eighty-one foxes were captured and subject to post-mortem analysis. Thirty-one foxes (38.3%) harboured helminths. A total of six helminth species were recovered. Only one adult of E. granulosus was found in the studied samples. The current study is the first report of the intestinal helminths of the patagonian grey fox in Tierra del Fuego, Argentina and showed that this specie is probably not an important reservoir host for E. granulosus.

  2. Charles Darwin and the oldestglacial events in Patagonia: the erratic blocks of the Río Santa Cruz valley

    Directory of Open Access Journals (Sweden)

    Jorge Strelin

    2009-04-01

    Full Text Available Althoughthe depositational environment assigned by Darwin to the large erratic blocksand gravels in the Río Santa Cruz valley has been reinterpreted, hisgeomorphological and stratigraphic observations are still in force. The largeerratic blocks he described as crowning the Condor Cliff terrace and spread atthe bottom of the valley just east of this locality (Sites 2 and 3, are nowinterpreted as indicators of the maximum glacial expansion in Patagonia.Similar blocks, though of a different lithology, accumulated over a lowerterrace located up-valley (Site 4, are now linked to moraines and glacifluvialterraces of the Penultimate Glaciation. Finally, in addition to the erraticblock discovered by Darwin in the lower Río Santa Cruz valley (Site 1, thereare others - recently discovered - which probably account for a catastrophicevent ascribed to a big glacier-lake outburst during the last interglacial.

  3. A new species of Ascocotyle (Trematoda: Heterophyidae) from the South American sea lion, Otaria flavescens, off Patagonia, Argentina.

    Science.gov (United States)

    Hernández-Orts, Jesús Servando; Montero, Francisco Esteban; Crespo, Enrique Alberto; García, Néstor Aníbal; Raga, Juan Antonio; Aznar, Francisco Javier

    2012-08-01

    We describe a new heterophyid species, Ascocotyle (Ascocotyle) patagoniensis n. sp., based on specimens collected from the intestines of the South American sea lion Otaria flavescens from Patagonia (Argentina). Ascocotyle (A.) patagoniensis n. sp. is distinguished from the other species of the subgenus by the number of circumoral spines, which are arranged in 2 rows of 18 to 23. The new species also differs from the other species in having a gonotyl without papillae. The specimens exhibited the widest seminal receptacle described for a species of this subgenus. Species of the subgenus Ascocotyle usually infect fish-eating birds or mammals in freshwater or brackish habitats. Ascocotyle (A.) patagoniensis n. sp. is the first species of the subgenus described from a marine mammal. However, no metacercariae of Ascocotyle spp. were found in 542 marine teleosts from 20 species collected in the same locality. The life cycle of the marine species from the Ascocotyle -complex infecting pinnipeds remains elusive.

  4. Late Cretaceous-early Eocene counterclockwise rotation of the Fueguian Andes and evolution of the Patagonia-Antarctic Peninsula system

    Science.gov (United States)

    Poblete, F.; Roperch, P.; Arriagada, C.; Ruffet, G.; Ramírez de Arellano, C.; Hervé, F.; Poujol, M.

    2016-02-01

    The southernmost Andes of Patagonia and Tierra del Fuego present a prominent arc-shaped structure: the Patagonian Bend. Whether the bending is a primary curvature or an orocline is still matter of controversy. New paleomagnetic data have been obtained south of the Beagle Channel in 39 out of 61 sites. They have been drilled in Late Jurassic and Early Cretaceous sediments and interbedded volcanics and in mid-Cretaceous to Eocene intrusives of the Fuegian Batholith. The anisotropy of magnetic susceptibility was measured at each site and the influence of magnetic fabric on the characteristic remanent magnetizations (ChRM) in plutonic rocks was corrected using inverse tensors of anisotropy of remanent magnetizations. Normal polarity secondary magnetizations with west-directed declination were obtained in the sediments and they did not pass the fold test. These characteristic directions are similar to those recorded by mid Cretaceous intrusives suggesting a remagnetization event during the normal Cretaceous superchron and describe a large (> 90°) counterclockwise rotation. Late Cretaceous to Eocene rocks of the Fueguian Batholith, record decreasing counterclockwise rotations of 45° to 30°. These paleomagnetic results are interpreted as evidence of a large counterclockwise rotation of the Fueguian Andes related to the closure of the Rocas Verdes Basin and the formation of the Darwin Cordillera during the Late Cretaceous and Paleocene. The tectonic evolution of the Patagonian Bend can thus be described as the formation of a progressive arc from an oroclinal stage during the closure of the Rocas Verdes basin to a mainly primary arc during the final stages of deformation of the Magallanes fold and thrust belt. Plate reconstructions show that the Antarctic Peninsula would have formed a continuous margin with Patagonia between the Early Cretaceous and the Eocene, and acted as a non-rotational rigid block facilitating the development of the Patagonian Bend.

  5. Multi-century tree-ring based reconstruction of the Neuquén River streamflow, northern Patagonia, Argentina

    Science.gov (United States)

    Mundo, I. A.; Masiokas, M. H.; Villalba, R.; Morales, M. S.; Neukom, R.; Le Quesne, C.; Urrutia, R. B.; Lara, A.

    2012-04-01

    In most cases, gauged river flow records in southern South America extend for only a few decades, hampering the detection of long-term, decadal to centennial-scale cycles and trends. Long streamflow series can be reconstructed from tree-ring records, offering the opportunity of extending the limited hydrological instrumental data to several centuries. In northern Patagonia, Argentina, the Neuquén River has great importance for local and national socio-economic activities such as hydroelectric power generation, agriculture and tourism. In this study, new and updated tree-ring chronologies from Araucaria araucana and Austrocedrus chilensis are used to reconstruct the October-June mean streamflow for the Neuquén River and place the period of gauged flows (1903-2009), in a long-term, multi-century context. The reconstruction covers the period 1346-2000 AD and was developed from a network of 43 tree-ring chronologies, grouped in composite series, using a nested principal component regression approach. Analyses of the frequency, intensity, and duration of droughts and pluvial events indicate that the 20th century contains some of the driest and wettest annual to decadal-scale events in the last 654 yr, but longer and more severe events were recorded in previous centuries. Blackman-Tukey and singular spectral analyses identified quasiperiodic oscillations from 3.5 to 17.5 yr. A dominant 6.8-yr cycle explains ca. 23.6% of the total variance in the Neuquén River streamflow reconstruction. Correlation analyses showed that discharges of the Neuquén River are related to variations in the Southern Annular Mode (SAM), a measure of air mass exchanges between middle and high latitudes in the Southern Hemisphere. This association is consistent with previous studies that indicate a strong correlation between rainfall in northern Patagonia and SAM variations.

  6. Análisis ontogénico de rasgos craneofaciales robustos en poblaciones humanas de Patagonia

    Directory of Open Access Journals (Sweden)

    González, Paula N.

    2007-01-01

    Full Text Available Las poblaciones humanas que habitaron el sur de Patagonia durante el Holoceno tardío presentan rasgos craneofaciales robustos que las diferencian del resto de los humanos modernos. El estudio de los factores causales de la robustez se ha basado en el análisis de individuos adultos, por lo tanto los mecanismos ontogénicos involucrados en la diferenciación de estas poblaciones son aún desconocidos. El objetivo de este trabajo es analizar la ontogenia de la robustez craneofacial en diversas poblaciones humanas. Se analizaron 5 muestras de individuos subadultos (Sad, de 5 a 15 años y adultos (Ad, procedentes del Noroeste Argentino y Patagonia (n=201. Se emplearon landmarks y semilandmarks con el fin de describir la glabela, los procesos frontal y zigomático, y el mastoides. Para establecer si los rasgos poblacionales específicos se encuentran presentes en Sad se compararon los patrones de ordenación de Ad y Sad obtenidos mediante un análisis de PROTEST. Los resultados indican que el patrón de variación morfológica se establece tempranamente en Sad. Se evaluó si la diferenciación en los Ad de las diversas poblaciones es atribuible al escalamiento ontogénico o a diferencias en las trayectorias. Los resultados muestran que si bien las poblaciones del sur alcanzan un mayor tamaño, las trayectorias ontogénicas entre las poblaciones estudiadas difieren significativamente. Por lo tanto, la robustez se establece tempranamente en la ontogenia postnatal y es modificada por la divergencia en los patrones de cambio en forma asociados a los cambios en tamaño.

  7. Multi-century tree-ring based reconstruction of the Neuquén River streamflow, northern Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    I. A. Mundo

    2011-10-01

    Full Text Available In most cases, gauged river flow records in southern South America exist for only a few decades, hampering the detection of long-term, decadal to centennial-scale cycles and trends. Long streamflow series can be reconstructed from tree-ring records, offering the opportunity of extending the limited hydrological instrumental data for several centuries or millennia. In northern Patagonia, Argentina, the Neuquén River has great importance for local and national socio-economic activities such as hydroelectric power generation, agriculture and tourism. In this study, new and updated tree-ring chronologies from Araucaria araucana and Austrocedrus chilensis are used to reconstruct the October–June mean streamflow for the Neuquén River and place the period of gauged flows, 1903–2009, in a long-term, multi-century context. The reconstruction covers the period 1346–2000 AD and was developed through a nested principal components regression approach using a network of 43 tree-ring chronologies grouped in composite series. Analyses of the frequency, intensity, and duration of droughts and pluvial events indicate that the 20th century contains some of the driest and wettest annual to decadal-scale events in the past millennium, but longer and more severe events can also be observed in previous centuries. Blackman-Tukey and Singular Spectral Analyses identified various multi-decadal quasiperiodic oscillations with a dominant 6.8-year cycle explaining ca. 23.6% of the total variance in the Neuquén River streamflow reconstruction. We also found that the Neuquén River discharges are related to variations in the Southern Annular Mode (SAM, a measure of air mass exchanges between middle and high latitudes in the Southern Hemisphere. This association is consistent with previous studies which indicate a strong connection between rainfall patterns in northern Patagonia and SAM activity.

  8. Multi-century tree-ring based reconstruction of the Neuquén River streamflow, northern Patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    I. A. Mundo

    2012-04-01

    Full Text Available In most cases, gauged river flow records in southern South America extend for only a few decades, hampering the detection of long-term, decadal to centennial-scale cycles and trends. Long streamflow series can be reconstructed from tree-ring records, offering the opportunity of extending the limited hydrological instrumental data to several centuries. In northern Patagonia, Argentina, the Neuquén River has great importance for local and national socio-economic activities such as hydroelectric power generation, agriculture and tourism. In this study, new and updated tree-ring chronologies from Araucaria araucana and Austrocedrus chilensis are used to reconstruct the October–June mean streamflow for the Neuquén River and place the period of gauged flows (1903–2009, in a long-term, multi-century context. The reconstruction covers the period 1346–2000 AD and was developed from a network of 43 tree-ring chronologies, grouped in composite series, using a nested principal component regression approach. Analyses of the frequency, intensity, and duration of droughts and pluvial events indicate that the 20th century contains some of the driest and wettest annual to decadal-scale events in the last 654 yr, but longer and more severe events were recorded in previous centuries. Blackman-Tukey and singular spectral analyses identified quasiperiodic oscillations from 3.5 to 17.5 yr. A dominant 6.8-yr cycle explains ca. 23.6% of the total variance in the Neuquén River streamflow reconstruction. Correlation analyses showed that discharges of the Neuquén River are related to variations in the Southern Annular Mode (SAM, a measure of air mass exchanges between middle and high latitudes in the Southern Hemisphere. This association is consistent with previous studies that indicate a strong correlation between rainfall in northern Patagonia and SAM variations.

  9. The sedimentology and dynamics of crater-affiliated wind streaks in western Arabia Terra, Mars and Patagonia, Argentina

    Science.gov (United States)

    Rodriguez, J.A.P.; Tanaka, K.L.; Yamamoto, A.; Berman, D.C.; Zimbelman, J.R.; Kargel, J.S.; Sasaki, S.; Jinguo, Y.; Miyamoto, H.

    2010-01-01

    Wind streaks comprise recent aeolian deposits that have been extensively documented on Venus, Earth and Mars. Martian wind streaks are among the most abundant surface features on the planet and commonly extend from the downwind margins of impact craters. Previous studies of wind streaks emerging from crater interior deposits suggested that the mode of emplacement was primarily related to the deposition of silt-sized particles as these settled from plumes. We have performed geologic investigations of two wind streaks clusters; one situated in western Arabia Terra, a region in the northern hemisphere of Mars, and another in an analogous terrestrial site located in southern Patagonia, Argentina, where occurrences of wind streaks emanate from playas within maar craters. In both these regions we have identified bedforms in sedimentary deposits on crater floors, along wind-facing interior crater margins, and along wind streaks. These observations indicate that these deposits contain sand-sized particles and that sediment migration has occurred via saltation from crater interior deposits to wind streaks. In Arabia Terra and in Patagonia wind streaks initiate from crater floors that contain lithic and evaporitic sedimentary deposits, suggesting that the composition of wind streak source materials has played an important role in development. Spatial and topographic analyses suggest that regional clustering of wind streaks in the studied regions directly correlates to the areal density of craters with interior deposits, the degree of proximity of these deposits, and the craters' rim-to-floor depths. In addition, some (but not all) wind streaks within the studied clusters have propagated at comparable yearly (Earth years) rates. Extensive saltation is inferred to have been involved in its propagation based on the studied terrestrial wind streak that shows ripples and dunes on its surface and the Martian counterpart changes orientation toward the downslope direction where it

  10. Study of cloud enhanced surface UV radiation at the atmospheric observatory of Southern Patagonia, Río Gallegos, Argentina

    Science.gov (United States)

    Wolfram, Elian A.; Salvador, Jacobo; Orte, Facundo; Bulnes, Daniela; D'Elia, Raul; Antón, Manuel; Alados-Arboledas, Lucas; Quel, Eduardo

    2013-05-01

    Ozone and ultraviolet (UV) radiation are two important issues in the study of Earth's atmosphere. The anthropogenic perturbation of the ozone layer has induced change in the amount of UV radiation that reaches the Earth's surface, mainly through the Antarctic ozone hole. Also clouds have been identified as the main modulator of UV amount over short time scales. While clouds can decrease direct radiation, they can produce an increase in the diffuse component, and as a consequence the surface UV radiation may be higher than during an equivalent clear sky scenario. In particular this situation can be important when a low ozone column and partially cloud coverered skies occur simultaneously. These situations happen frequently in southern Patagonia, where the CEILAP Lidar Division has established the Atmospheric Observatory of Southern Patagonia, an atmospheric remote sensing site near the city of Río Gallegos (51°55'S, 69°14'W). In this paper, the impact of clouds on UV radiation is investigated by the use of ground based measurements from the passive remote sensing instruments operating at this site, mainly broad and moderate narrow band filter radiometers. Cloud modification factors (CMF, ratio between the measured UV radiation in a cloudy sky and the simulated radiation under cloud-free conditions) are evaluated for the study site. CMFs higher than 1 are found during spring and summer time, when lower total ozone columns, higher solar elevations and high cloud cover occur simultaneously, producing extreme erythemal irradiance at the ground surface. Enhancements as high as 25% were registered. The maximum duration of the enhancement was around 30 minutes. This produces dangerous sunbathing conditions for the Río Gallegos citizen.

  11. Deployable centralizers

    Energy Technology Data Exchange (ETDEWEB)

    Grubelich, Mark C.; Su, Jiann-Cherng; Knudsen, Steven D.

    2017-02-28

    A centralizer assembly is disclosed that allows for the assembly to be deployed in-situ. The centralizer assembly includes flexible members that can be extended into the well bore in situ by the initiation of a gas generating device. The centralizer assembly can support a large load carrying capability compared to a traditional bow spring with little or no installation drag. Additionally, larger displacements can be produced to centralize an extremely deviated casing.

  12. Recent acceleration of ice loss in the Northern Patagonia Icefield based on an updated decennial evolution

    Directory of Open Access Journals (Sweden)

    P. López

    2011-12-01

    Full Text Available Ice elevation changes of the Northern Patagonia Icefield (NPI were analyzed by comparing three Digital Elevation Models (DEM corresponding to 1975 (constructed based on topographic maps, the SRTM DEM of 2000 yr and a SPOT 5 DEM of 2005. In addition, the glacier length fluctuations and the surface area evolution between 2001 and 2011 of 25 glaciers of the NPI were studied: the information extracted from the Landsat ETM+ satellite image of 11 March 2001 was compared to the measurements performed based on the Landsat ETM+ satellite image of 19 February 2011. From a global point of view, the majority of the studied glaciers thinned, retreated and lost surface between 2001 and 2011, only few glaciers (Leones, Nef, Pared Sur and Soler located on the eastern side of the NPI have been stable. Glaciers located on the western side of the NPI suffered a stronger wasting compared to the glaciers located on the eastern side.

    Overall, over the ablation areas of the NPI (below 1150 m a.s.l. a more rapid thinning of 2.6 m yr−1 occurred between 2000 and 2005 yr compared to the period 1975–2000, in which a mean thinning of 1.7 m yr−1 was measured for the same zones of the NPI. For the whole period (1975–2005 the most important thinning of the ablation areas has been estimated for HPN-1 Glacier (4.4 m yr−1 followed by Benito (3.4 m yr−1, Fraenkel (2.4 m yr−1, Gualas (2.1 m yr−1 and Acodado glaciers, all of them located on the western side of the NPI.

    Between 2001 and 2011, a noteworthy retreat of 1.9 km was experienced by Gualas Glacier and by Reichert Glacier with 1.6 km, both located on the north-western side of the NPI. On the south-western side of the NPI, during the same decennia, Steffen Glacier experienced a remarkable retreat of 1.6 km as well. During the 2001–2011 period, Steffen Glacier more than doubled its rate of retreat (compared to the 1979–2001

  13. Recent acceleration of ice loss in the Northern Patagonia Icefield based on an updated decennial evolution

    Science.gov (United States)

    López, P.; Casassa, G.

    2011-12-01

    Ice elevation changes of the Northern Patagonia Icefield (NPI) were analyzed by comparing three Digital Elevation Models (DEM) corresponding to 1975 (constructed based on topographic maps), the SRTM DEM of 2000 yr and a SPOT 5 DEM of 2005. In addition, the glacier length fluctuations and the surface area evolution between 2001 and 2011 of 25 glaciers of the NPI were studied: the information extracted from the Landsat ETM+ satellite image of 11 March 2001 was compared to the measurements performed based on the Landsat ETM+ satellite image of 19 February 2011. From a global point of view, the majority of the studied glaciers thinned, retreated and lost surface between 2001 and 2011, only few glaciers (Leones, Nef, Pared Sur and Soler) located on the eastern side of the NPI have been stable. Glaciers located on the western side of the NPI suffered a stronger wasting compared to the glaciers located on the eastern side. Overall, over the ablation areas of the NPI (below 1150 m a.s.l.) a more rapid thinning of 2.6 m yr-1 occurred between 2000 and 2005 yr compared to the period 1975-2000, in which a mean thinning of 1.7 m yr-1 was measured for the same zones of the NPI. For the whole period (1975-2005) the most important thinning of the ablation areas has been estimated for HPN-1 Glacier (4.4 m yr-1) followed by Benito (3.4 m yr-1), Fraenkel (2.4 m yr-1), Gualas (2.1 m yr-1) and Acodado glaciers, all of them located on the western side of the NPI. Between 2001 and 2011, a noteworthy retreat of 1.9 km was experienced by Gualas Glacier and by Reichert Glacier with 1.6 km, both located on the north-western side of the NPI. On the south-western side of the NPI, during the same decennia, Steffen Glacier experienced a remarkable retreat of 1.6 km as well. During the 2001-2011 period, Steffen Glacier more than doubled its rate of retreat (compared to the 1979-2001 period) and experienced the disintegration of its main front as well as a lateral tongue that retreated 3.1 km. The

  14. Geophysical characterization of two circular structures at Bajada del Diablo (Patagonia, Argentina): Indication of impact origin

    Science.gov (United States)

    Prezzi, Claudia B.; Orgeira, María Julia; Acevedo, Rogelio D.; Ponce, Juan Federico; Martinez, Oscar; Rabassa, Jorge O.; Corbella, Hugo; Vásquez, Carlos; González-Guillot, Mauricio; Subías, Ignacio

    2012-02-01

    An impact origin has been proposed for the circular structures found in Bajada del Diablo, Patagonia, Argentina. Taking into account its extension and the number of impact structures, Bajada del Diablo would be the largest meteoritic impact areas known on Earth, being an extremely interesting area for the research of impact events and processes. Moreover, the global distribution of known impact structures shows a surprising asymmetry. Particularly, South America has only seven described areas. It is evident that this situation is an artifact, highlighting the importance of intensifying the research in the least studied areas such as Argentina. Circular structures in Bajada del Diablo have been identified on two rock types: the Quiñelaf eruptive complex and Pampa Sastre Formation. In the first case, circular structures are placed in olivine basalts. On the other hand, Pampa Sastre Formation (late Pliocene/early Pleistocene) corresponds to conglomerate layers with basalt clasts boulder and block in size in a coarse sandy matrix. With the aim of further the investigation of the proposed impact origin for these circular structures, we carried out detailed topographic, magnetic and electromagnetic ground surveys in two circular structures ("8" and "A") found in Pampa Sastre conglomerates. Both circular structures are simple, bowl-shaped with rim diameters of 300 m and maximum depths of 10 m. They have been partially filled in by debris flows from the rims and wind-blown sands. Two preliminary magnetic profiles have also been carried out in circular structure "G" found in Quiñelaf basalts. The magnetic anomalies show a circular pattern with a slightly negative and relatively flat signal in the circular structures' bases. Furthermore in the circular structures' rims, high-amplitude, conspicuous and localized (short wavelength) anomalies are observed. Such large amplitude and short wavelength anomalies are not detected outside the circular structures. For all used

  15. Environmental History of Southern Patagonia Unraveled by Seismic Stratigraphy and Sediment Cores of Laguna Potrok Aike

    Science.gov (United States)

    Anselmetti, F. S.; Ariztegui, D.; de Batist, M.; Gebhardt, C.; Haberzettl, T.; Niessen, F.; Ohlendorf, C.; Zolitschka, B.

    2006-12-01

    Laguna Potrok Aike, located in Southernmost Patagonia (Argentina, 52°S) is a maar lake and likely provides the only continental Southern Patagonian archive that covers a long and continuous interval of several glacial- to-interglacial cycles. In the context of a proposed ICDP-drilling initiative (see Zolitschka et al., this session), several site surveys have been undertaken that characterize in detail the shallow subsurface of the lake. A variety of environmental changes are identified based on seismic stratigraphic analyses of a dense grid of high- resolution data. Long sediment cores recovered the material to date and calibrate these changes providing a chronology of events. The paleoenvironmental history reflects the complex interplay between variations in the hydrologic cycle, wind regime, and volcanic/tectonic activity. Laguna Potrok Aike is the largest and deepest lake (maximum depth 100 m) in the Pali Aike Volcanic Field. It is steeply-rimmed, circular in shape with a diameter of 3 km and surrounded subaerially by a series of paleoshorelines, reflecting its sensitivity to changes in the evaporation/precipitation ratio. Seismic subsurface data indicate a basinwide erosional unconformity, that consistently occurs on the shoulder of the lake down to a depth of -35 m (below modern lake level) marking the lowest lake level during the Late Glacial-to-Holocene times. Cores that penetrate this unconformity comprise MIS3-dated sediments (45 ka) 3.5 m below the unconformity that were deposited during high lake levels. These cores also provide an age of 6800 cal BP for the transgressional sediments burying the unconformity. This middle Holocene transgression following the maximum lake level lowstand marks the onset of a stepwise increase in moisture, as shown by a series of buried paleoshorelines that were formed during at least five lake level stillstands between the depths of -32 and -12 m. No indications point towards an intermittent lake level lowering, so that

  16. Unravelling the collapse mechanisms at a Jurassic caldera of the Chon Aike silicic LIP in Southern Patagonia (47° 15 'S, 71° 40'W), Argentina

    Science.gov (United States)

    Sruoga, P.; Japas, S.; Salani, F.; Kleiman, L.; Graffigna, M.

    2008-10-01

    La Peligrosa Caldera is located at Sierra Colorada (47° 15'S, 71° 40' W) in the Chon-Aike silicic LIP. It represents an unique window to understand the eruptive mechanisms that prevailed throughout the ignimbritic flare-up in Southern Patagonia during middle to late Jurassic times. Key pieces of lithologic and structural evidences are taken into account to reconstruct the volcanic structure.

  17. Una mirada arqueológica sobre la arquitectura doméstica en tierra en la Patagonia argentina durante los siglos XVIII, XIX y XX

    OpenAIRE

    Casanueva, María Laura

    2016-01-01

    Este artículo busca poner en valor las estrategias que permitieron la supervivencia y permanencia de inmigrantes campesinos, que en distintos momentos históricos y bajo diferentes coyunturas políticas, arribaron a la Patagonia argentina en busca de un progreso económico y patrimonial. La necesidad de cobijo urgente y de hacer frente a las adversidades en un nuevo destino territorial y social, provocaron respuestas concretas. Las viviendas levantadas por aquellos pioneros europeos so...

  18. Paleoecología: el uso de los quironómidos fósiles (Diptera: Chironomidae en reconstrucciones paleoambientales durante el Cuaternario en la Patagonia Paleoecology: the use of fossil chironomids (Diptera: Chironomidae for paleoenvironmental reconstructions in Patagonia

    Directory of Open Access Journals (Sweden)

    Julieta Massaferro

    2009-06-01

    Full Text Available Entre los indicadores biológicos lacustres más utilizados en las reconstrucciones ambientales, se encuentran el polen, los ostrácodos y las diatomeas, y entre los insectos, los coleópteros y los quironómidos. Este grupo ha cobrado gran importancia en los últimos tiempos, debido a los resultados prometedores que se han obtenido en reconstrucciones climáticas realizadas en América del Norte y Europa. En América del Sur, el uso de los quironómidos fósiles en estudios cuaternarios es relativamente limitado, principalmente por su escaso conocimiento taxonómico regional. La mayor parte de estos estudios fueron realizados en lagos glaciares patagónicos de Argentina y Chile. Las larvas de quironómidos constituyen una valiosa herramienta paleolimnológica, por ser un grupo de organismos altamente sensible a cambios ambientales, tanto naturales como artificiales. Además, es un grupo de insectos ampliamente distribuido y con una abundancia y diversidad relativamente altas. Sus cápsulas cefálicas se preservan en los sedimentos lacustres y poseen caracteres importantes que permiten identificar géneros y muchas veces especies. El estudio de los ensambles de quironómidos en sedimentos lacustres puede ser utilizado con distintos objetivos, por ejemplo, para estudios de eutrofización, ya que responden rápidamente a cambios en la concentración de nutrientes, materia orgánica y otros elementos, como metales pesados. No obstante, uno de los potenciales más importantes de este grupo de insectos es su sensibilidad a los cambios de temperatura, por este motivo, la aplicación más importante de su estudio en sedimentos se centra en las reconstrucciones climáticas. Esta contribución es una síntesis de los resultados de los trabajos publicados en la Patagonia argentina y chilena, sobre la base del uso de los quironómidos fósiles en reconstrucciones paleoambientales.Pollen, ostracods, diatoms and insects such as beetles and chironomids are

  19. Diversity, distribution and floral specificity of tangle-veined flies (Diptera: Nemestrinidae in north west Patagonia, Argentina Diversidad, distribución y especificidad floral de nemestrínidos (Diptera en el noroeste de la Patagonia, Argentina

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    MARIANO DEVOTO

    2006-03-01

    Full Text Available Tangle-veined flies (Nemestrinidae constitute a primitive and rather widespread family among Diptera. The genus Trichophthalma occurs in Australia and South America and is the only one in the family with a typically Gondwanian, disjoint distribution. The ecology and distribution of most southern South American species of this genus remains virtually unknown. We studied the diversity, distribution and flower specificity of flower-visiting species of the genus Trichophthalma in the temperate forests of southern South America in ten sites along an east-west rainfall gradient (37-40°S on the eastern slope of the Andes. We recorded nine species of Trichophthalma, which showed an overlapped distribution along the gradient and different degrees of floral specificity. Three species are reported for Argentina for the first time and three are first recorded as flower visitors to the local flora. Our results show that while in southern Africa tangle-veined flies are engaged in highly specialized pollination interactions with long-tubed species, the Trichophthalma spp. of Patagonia share their flowers with a diverse and rather unspecialized visitor fauna among which several species of flies, bees and birds are presentLos nemestrínidos constituyen una familia de Dípteros primitiva y de amplia distribución. El género Trichophthalma se encuentra en Australia y Sudamérica y es el único en la familia con una distribución disjunta típicamente gondwánica. La ecología y distribución de la mayoría de las especies sudamericanas permanecen virtualmente desconocidas. Estudiamos la diversidad, distribución y especificidad floral de las especies del género Trichophthalma de los bosques templados del sur de Sudamérica en diez sitios ubicados a lo largo de un gradiente de precipitación este-oeste (37-40°S sobre la vertiente occidental de los Andes. Registramos nueve especies de Trichophthalma, las cuales mostraron una distribución superpuesta a lo largo

  20. No hubo desierto alguno… “la tierra tiene vida porque estamos vivos”

    OpenAIRE

    2016-01-01

    A diferencia del norte de la Patagonia, el sur de Chubut y Santa Cruz no fue escenario de las batallas libradas por el Ejército Argentino en contra de los pueblos indígenas durante la “Campaña del desierto” Esto contrasta con el conocimiento que actualmente tenemos acerca de la historia de la ocupación indígena. La profundidad temporal se basa en el aporte de la arqueología, que remonta la ocupación a 16,000 y 13,000 años atrás, en la Meseta central de Santa Cruz. También proviene de una ren...

  1. Reconstruction and modelling of the 1977 Glacial Lake Outburst Flood (GLOF) of the Engaño Lake, Chilean Patagonia.

    Science.gov (United States)

    Iribarren Anacona, Pablo; Norton, Kevin; Mackintosh, Andrew

    2015-04-01

    Floods from moraine-dammed lake failures can result in severe damage to mountain communities. GLOFs can also cause long-standing effects in riverine landscapes, due to the high intensity (i.e. great depth and high velocities) and long reach capacity of these events. GLOFs may increase in frequency as glaciers retreat and new lakes develop, highlighting the need for a better understanding of GLOF dynamics and the measures to reduce their negative outcomes. In Patagonia at least 16 moraine-dammed lakes have failed in historic time, however, data about GLOF dynamics and impacts are limited since GLOFs have mainly affected uninhabited areas and ungauged rivers. In March 1977, however, a GLOF flooded a small village (~130 inhabitants) in Chilean Patagonia. We reconstruct the dynamics of this event by semi-structured interviews, interpretation of satellite images (Landsat MSS) and two dimensional (2D) hydraulic modelling (using HEC-RAS 5.0 BETA and the SRTM v4 DEM). This reconstruction provides insights into GLOF behaviour, as well as the planning issues that led to socioeconomic consequences, which included relocation of the village. We mapped the flood extent and compiled data of flood depth and timing to constrain the 2D GLOF simulations. Modelling shows that the water released by the GLOF was in the order of 12-13 million cubic metres and that the flood reached Bahía Murta Viejo, located ~26 km from the failed lake, 2-3 hours after the moraine dam was breached. The flood lasted for about ten hours (at the village), although the peak discharge occurred after only one hour at this site. The maximum water depth at Bahía Murta Viejo was 1.5 m, however, water depths of up to 20 metres were simulated in upstream constricted reaches. The overall flood dynamics suggested by interviews and geomorphic mapping, including hydraulic ponding upstream of bedrock gorges, was well represented in the 2D simulations in spite of the coarse resolution (~80 m) of the DEM used. The

  2. Propiedades microbiológicas en un suelo de la patagonia argentina bajo la influencia de diferentes especies forestales Microbiological properties of a soil of the argentine patagonia under the influence of different tree species

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    Diana Noemí Effron

    2011-12-01

    Full Text Available En los sistemas forestales, la hojarasca es generalmente la principal fuente de nutrientes para la vegetación y microorganismos, pudiendo variar éstos en relación a la biomasa y calidad de los materiales aportados por diferentes especies. Las raíces de los árboles ejercen influencia en el desarrollo y actividad de la microflora. El objetivo de este trabajo fue evaluar la influencia sobre el suelo de dos especies arbóreas implantadas, con distinta composición del residuo vegetal aportado al suelo. El suelo está clasificado como un Andisol y está ubicado en la Estación Forestal Trevelín, Chubut, Argentina, Lat. 43º Sur, Long 71º31´ Oeste. Se extrajeron muestras superficiales de suelo de dos parcelas de bosque con una especie dominante cada una: Pino radiata (Pinus radiata D. Don. y Roble europeo (Quercus robur. Se determinó carbono orgánico, respiración microbiana, actividad deshidrogenasa, diversidad funcional de comunidades microbianas asociadas y se calculó el índice de diversidad de Shanon Weaver (H. Se cuantificaron bacterias totales, bacterias amilolíticas, actinomicetes y hongos. Los valores de respiración microbiana y carbono orgánico resultaron significativamente superiores en el suelo debajo de Roble. No se encontraron diferencias significativas entre valores de deshidrogenasa. Los recuentos de flora bacteriana total y de bacterias amilolíticas dieron significativamente superiores en el suelo asociado a Roble, mientras que los actinomicetes y hongos no mostraron diferencias significativas entre especies. El análisis de componentes principales mostró variaciones significativas en la fisiología de las comunidades microbianas asociadas a estas dos especies. El índice de diversidad H de la microflora fue significativamente mayor para Pino. Los residuos de Roble por ser una especie latifoliada y por lo tanto poseer menor contenido de sustancias recalcitrantes que una conífera, asociado al mayor desarrollo de

  3. Inventario preliminar y nuevos registros de Psychodidae no Phlebotominae (Diptera, Nematocera para Argentina, con especial referencia a la Patagonia Preliminary inventory and new records of non Phlebotominae Psychodidae (Diptera, Nematocera for Argentina, with special emphasis to the Patagonian region

    Directory of Open Access Journals (Sweden)

    Guillermo H. Omad

    2012-12-01

    Full Text Available La familia Psychodidae incluye pequeños dípteros nematóceros de distribución cosmopolita. Phlebotominae, en virtud de su importancia sanitaria, ha recibido una adecuada atención y han sido descriptas más de 400 especies para América del Sur. Por el contrario, la contraparte no Phlebotominae de la familia ha sido pobremente estudiada y su conocimiento en la región es escaso. El conocimiento de las Psychodidae no Phlebotominae en la Argentina es escaso, ya que el mismo se restringe a 19 especies agrupadas en 9 géneros. El objetivo de este trabajo es presentar una lista actualizada de Psychodidae para Argentina, donde se amplía el número de géneros a 11, con aproximadamente 24 especies, se registran a su vez nueve especies aún no descriptas y se incluyen cuatro nuevos registros para la Argentina: Alepia copelata Quate, Alepia truncata Bravo, Trichomyia aurea Duckhouse y Trichomyia figuieroai Duckhouse; y tres para la provincia de Chubut: Desmioza speciosa (Tonnoir, Nemoneura confraga Quate & Brown y Nemoneura dealbata Tonnoir. Los sitios de muestreo para este trabajo se realizaron en diferentes zonas de las provincias de Chubut (Parque Nacional Los Alerces, Río Negro y Neuquén (Parque Nacional Nahuel Huapi, Buenos Aires y Misiones.The family Psychodidae includes small cosmopolitan nematoceran flies. The Phlebotominae have received widespread attention due to their public health importance, and over 400 species have been described in South America. Nevertheless, the non Phlebotominae members of the family have been poorly studied, and their knowledge in the region is poor. In Argentina, the non Phlebotominae Psychodidae are scarcely known, with 19 recorded species included in 9 genera. The aim of this contribution is to present an updated list of Psychodidae from Argentina, extending the number of genera to 11 with approximately 24 species, including nine as yet undescribed taxa and four new records for the country: Alepia copelata

  4. CO2 and CH4 fluxes of contrasting pristine bogs in southern Patagonia (Tierra del Fuego, Argentina)

    Science.gov (United States)

    Münchberger, Wiebke; Blodau, Christian; Kleinebecker, Till; Pancotto, Veronica

    2015-04-01

    South Patagonian peatlands cover a wide range of the southern terrestrial area and thus are an important component of the terrestrial global carbon cycle. These extremely southern ecosystems have been accumulating organic material since the last glaciation up to now and are - in contrast to northern hemisphere bogs - virtually unaffected by human activities. So far, little attention has been given to these pristine ecosystems and great carbon reservoirs which will potentially be affected by climate change. We aim to fill the knowledge gap in the quantity of carbon released from these bogs and in what controls their fluxes. We study the temporal and spatial variability of carbon fluxes in two contrasting bog ecosystems in southern Patagonia, Tierra del Fuego. Sphagnum-dominated bog ecosystems in Tierra del Fuego are similar to the ones on the northern hemisphere, while cushion plant-dominated bogs can almost exclusively be found in southern Patagonia. These unique cushion plant-dominated bogs are found close to the coast and their occurrence changes gradually to Sphagnum-dominated bogs with increasing distance from the coast. We conduct closed chamber measurements and record relevant environmental variables for CO2 and CH4 fluxes during two austral vegetation periods from December to April. Chamber measurements are performed on microforms representing the main vegetation units of the studied bogs. Gas concentrations are measured with a fast analyzer (Los Gatos Ultraportable Greenhouse Gas Analyzer) allowing to accurately record CH4 fluxes in the ppm range. We present preliminary results of the carbon flux variability from south Patagonian peat bogs and give insights into their environmental controls. Carbon fluxes of these two bog types appear to be highly different. In contrast to Sphagnum-dominated bogs, cushion plant-dominated bogs release almost no CH4 while their CO2 flux in both, photosynthesis and respiration, can be twice as high as for Sphagnum

  5. Asuntos de familia: La construcción del poder en la patagonia: el caso de Neuquén

    Directory of Open Access Journals (Sweden)

    Susana Bandieri

    2005-12-01

    Full Text Available Este trabajo pretende aproximarse al proceso de constitución de los sectores dominantes en la Patagonia a partir del estudio de los grupos terratenientes y mercantiles, muchas veces subsumidos en un único sujeto social. Para ello, se analiza la formación de los más importantes grupos familiares vinculados a la propiedad de la tierra y a la producción de bienes ganaderos, así como al comercio en sus múltiples expresiones, rurales y urbanas. Se pone especial énfasis en descubrir las estrategias de acumulación de estos grupos, ya sean las referidas a los adelantos a la producción, al manejo del crédito y a la provisión de bienes a los diversos gobiernos de los Territorios Nacionales, así como las vinculadas a las ventajas comparativas brindadas por el aprovechamiento simultáneo de los mercados del Atlántico y del Pacífico. Finalmente, se estudian los vínculos surgidos a partir de los lazos étnicos, particularmente importantes en el caso de las familias sirio-libanesas de Neuquén, y se representan asimismo los entramados de poder a que dieron lugar los entrecruzamientos familiares de los distintos ejemplos estudiados.This paper offers an approach to the process of consolidation of dominant sectors in Patagonia from the study of landowners and merchant groups, traditionally reduced to a single social subject. The formation of the most important family groups entailed to land property and cattle ranching is studied, as so the urban and rural trade is also included. A special emphasis is put to find this groups' accumulation strategies, which were related to production advancements, credit management and the supply of goods to the different governments of the National Territories . Likewise, this article shows those strategies based on the exploitation of comparative advantages obtained from the simultaneous handling of Atlantic and Pacific markets. Finally, relations spouted from ethnic ties are analyzed because they are very

  6. Intestinal helminth fauna of the South American sea lion Otaria flavescens and fur seal Arctocephalus australis from northern Patagonia, Argentina.

    Science.gov (United States)

    Hernández-Orts, J S; Montero, F E; Juan-García, A; García, N A; Crespo, E A; Raga, J A; Aznar, F J

    2013-09-01

    We report on the intestinal helminth fauna of 56 South American sea lions, Otaria flavescens, and 5 South American fur seals, Arctocephalus australis, from northern Patagonia, Argentina. A total of 97,325 helminth specimens were collected from sea lions. Gravid individuals were represented by 6 species of parasites: 1 digenean (Ascocotyle (Ascocotyle) patagoniensis), 1 cestode (Diphyllobothrium spp.), 3 nematodes (Uncinaria hamiltoni, Contracaecum ogmorhini s.s., Pseudoterranova cattani) and 1 acanthocephalan (Corynosoma australe). In addition, third-stage larvae of 2 nematodes (Contracaecum sp. and Anisakis sp. type I) and 3 juvenile acanthocephalans (Andracantha sp., Profilicollis chasmagnathi and Corynosoma cetaceum) were also collected. Andracantha sp., C. ogmorhini s.s. and P. chasmagnathi represent new host records. A total of 1516 helminth specimens were collected from fur seals. Gravid individuals were represented by three species of parasites, namely, Diphyllobothrium spp., C. ogmorhini s.s. and C. australe. In addition, larvae of Contracaecum sp. and P. cattani, juveniles of C. cetaceum and immature cestodes (Tetrabothriidae gen. sp.) were also collected. Corynosoma australe was the most prevalent and abundant parasite in both hosts, accounting for >90% of all specimens. Sea lions and furs seals from northern Patagonia harbour the intestinal helminth communities that could be predicted for otariids, i.e. the combination of species of the genera Corynosoma, Diphyllobothrium, Pseudoterranova, Contracaecum and, in pups, Uncinaria. Additionally, both species of otariid are apparently unsuitable hosts (i.e. non-hosts) for as many as five parasite taxa. The inclusion or exclusion of these species affects estimation of species richness at both component community (11 versus 6 species in sea lions; 7 versus 3 species in fur seals) and infracommunity (mean: 3.1 versus 2.6 in sea lions; 2.2 versus 1.7 species) levels. Information about the reproductive status of

  7. Parasitological findings of lesser rhea, Pterocnemia pennata (D´ ORBIGNY in faeces FROM NORTHERN PATAGONIA, ARGENTINA Hallazgos parasitológicos en deposiciones de Lesser Rhea, Pterocnemia Pennata (D'orgiby, del norte de la patagonia, Argentina

    Directory of Open Access Journals (Sweden)

    E. Chang Reissig

    2001-01-01

    Full Text Available La información acerca de parásitos que afectan a la producción de choiques criados en granjas en Argentina es escasa. El objetivo de este estudio fue determinar la prevalencia de enfermedades parasitarias en granjas de choiques. Durante un año se realizaron muestreos periódicos en 10 granjas de choiques (Pterocnemia pennata localizadas en el norte de la Patagonia Argentina. Un total de 310 muestras de materia fecal fresca de pichones, juveniles y adultos fueron recolectadas y analizadas por las técnicas de Willis y McMaster. De 310 muestras de material fecal analizadas, 31.3% de las muestras presentaron ooquistes de Eimeria spp, 1.9% huevos de Capillaria sp y 8.7% huevos de Trichostrongylus sp. Los recuentos de huevos y ooquistes por gramo de materia fecal resultaron bajos en la mayoría de los análisis. Se registró infección por Capillaria sp (Nematoda en 32% de las aves de una granja. De acuerdo a nuestros resultados, las infecciones parasitarias en choiques no constituirían un grave problema en los sistemas productivos de Argentina. Este es el primer estudio realizado en Argentina que reporta el nivel de parasitismo en choiques criados en granjas

  8. Cambios en lagos y circulación fluvial vinculados al calentamiento climático del Pleistoceno tardío-Holoceno temprano en Patagonia e isla 25 de mayo, islas Shetland del Sur, Antártida

    Directory of Open Access Journals (Sweden)

    R.A. del Valle

    2007-12-01

    Full Text Available El calentamiento clim ático que afectó a la Patagonia en el Pleistoceno tardío-Holoceno temprano produjo cambios en la morfología del paisaje, incluyendo la génesis, desarrollo y desintegración de grandes lagos al este de los Andes. Hasta entonces, los glaciares y sus morenas formaban diques naturales que embalsaron las aguas de deshielo y mantenían alto el nivel de las aguas en los grandes paleolagos. Posteriormente, la migración hacia el sur de la mejoría climática ocasionó la progresiva fusión del campo de hielo regional, y las morenas fueron cortadas por la erosión fluvial, cuando el calentamiento climático impactó plenamente en la región. El proceso afectó a la región de norte a sur en tiempos diferentes: 1 hace c. 13.200 años en el norte, 2 durante la transición Pleistoceno/Holoceno en la parte central, y 3 finalmente, en Tierra del Fuego hace unos 7.800 años. El rápido retroceso de los glaciares produjo el desalojo de los valles andinos a ambos lados de la cordillera, lo cual abrió cauces fluviales que atraviesan la cordillera desde entonces, inaugurando el drenaje hacia el océano Pacífico de grandes lagos glaciales que existían al oriente de los Andes. Esto resultó en el rápido descenso del nivel de los paleolagos. Un proceso similar ocurrió en las islas Shetland del Sur (Antártida hace unos 6.000 años.

  9. "Acá nunca pasa nada" Trelew (Patagonia Argentina y Vitoria (País Vasco, España. Polos de desarrollo, dictaduras y la intención de borrar la historia.

    Directory of Open Access Journals (Sweden)

    Pérez Álvarez, Gonzalo

    2016-12-01

    Full Text Available Este artículo rastrea el paralelo observado entre los procesos de instalación de polos de desarrollo en Argentina y España, impuestos durante dictaduras en las décadas del '60 y '70, la intención de sostener una narración histórica que ocultase el conflicto en las regiones intervenidas, y las prácticas obreras que hacían evidente la presencia de la lucha y el cambio, justamente allí donde los discursos oficiales pretendían imponer que "nunca pasaba nada". Mostramos que el ocultamiento de la historia, y por lo tanto del conflicto, era necesario a las dictaduras y a sus pretensiones de planificar, de manera autoritaria, el modelo de desarrollo que estas regiones debían llevar adelante. Para ello rastreamos el proceso en dos ciudades claramente diferentes y muy alejadas entre sí: Trelew, en la región central de la Patagonia Argentina, y Vitoria, la provincia más al sur del País Vasco. Así evidenciamos una de las características de las dictaduras en las ciudades pequeñas: una pretensión de regir los destinos de todo y de todos, hasta el punto de pretender sancionar que en esos lugares no existía la historia, y que eran ellos quienes planificarían su futuro. Pero los trabajadores tendrían otras cosas para decir.

  10. Levels of essential and toxic elements in Porphyra columbina and Ulva sp. from San Jorge Gulf, Patagonia Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Adriana Angela [Catedras de Toxicologia y Quimica Legal, Biologia y Bromatologia y Nutricion, Universidad Nacional de la Patagonia San Juan Bosco, Chubut (Argentina); Farias, Silvia Sara [Comision Nacional de Energia Atomica, Gerencia de Tecnologia y Medio Ambiente, Buenos Aires (Argentina); Strobl, Analia Mabel [Catedras de Toxicologia y Quimica Legal, Biologia y Bromatologia y Nutricion, Universidad Nacional de la Patagonia San Juan Bosco, Chubut (Argentina); Perez, Laura Beatriz [Catedras de Toxicologia y Quimica Legal, Biologia y Bromatologia y Nutricion, Universidad Nacional de la Patagonia San Juan Bosco, Chubut (Argentina); Lopez, Clara Magdalena [Catedra de Toxicologia y Quimica Legal, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (Argentina); Pineiro, Adriana [Catedra de Toxicologia y Quimica Legal, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (Argentina); Roses, Otmaro [Catedra de Toxicologia y Quimica Legal, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires (Argentina); Fajardo, Maria Angelica [Catedras de Toxicologia y Quimica Legal, Biologia y Bromatologia y Nutricion, Universidad Nacional de la Patagonia San Juan Bosco, Chubut (Argentina)]. E-mail: copipat@sinectis.com.ar

    2007-04-15

    Baseline concentration levels of As, B, Ca, Cd, Cr, Cu, Co, Fe, Mg, Mn, Mo, Ni, P, Pb, Se, V, and Zn were determined for Porphyra columbina and Ulva sp. collected from three locations along San Jorge Gulf, in Patagonia Argentina. Elements were quantified by inductively coupled plasma-optical emission spectrometry, with the exception of lead and cadmium in some samples which were determined by electrothermal atomic absorption spectrometry. Three stations with different exposure degree to human activities, Bahia Solano, the mouth of Arroyo La Mata stream and Punta Maqueda, were selected as sampling points. The results showed a wide range of metal retention capacity between the two studied species. Regarding the levels of pollutants found in the researched sites, Punta Maqueda seemed to be less influenced by anthropogenic activities than the other two sites except for Cd. Taking into account their toxicities seasonal variations in Pb and Cd levels were studied in both algae in Punta Maqueda. Maximum concentrations of Cd (9.8 {mu}g g{sup -1} dry wt.) were observed in P. columbina during winter, and maximum levels of Pb (0.82 {mu}g g{sup -1} dry wt.) were detected in Ulva sp. during summer. Legislative and health safety aspects were evaluated for Cd and Pb.

  11. Water Law, Mining and Hydro-Energy Conflicts in South America: Tales from the Andes and Patagonia

    Directory of Open Access Journals (Sweden)

    Victor Tafur

    2011-10-01

    Full Text Available Conflicts in connection with hydro-energy and mining activities vis-à-vis other water uses, mainly human consumption, agriculture, industry, tourism, or even the essential flows needed for ecosystem protection, call into question whether South America’s path in the 21st Century will be characterized as ‘open veins’ (borrowing from the title of Uruguayan writer Eduardo Galeano’s book or sustainable development. In this era of ‘New Conquistadors’, as some have called it, the key question is whether water law and environmental legal frameworks in the region are fit to deal with the pressure posed by these extracting industries. The paper seeks to contribute to this debate by discussing legal issues in connection with a controversial gold mining project in the Argentina-Chile border and a hydro-energy project in the Chilean Patagonia. The goal of the paper is to provide a South American perspective of water law through the lens of conflict. The paper concludes that water-related conflicts in these projects reveal weaknesses in the regulatory scheme for such endeavours and underscores the need to adopt reforms or implement mechanisms to ensure that water resources are adequately assessed, protected, and monitored.

  12. Pensar una Patagonia con dos océanos: el proyecto de desarrollo de Ezequiel Ramos Mexía

    Directory of Open Access Journals (Sweden)

    Susana Bandieri

    2009-01-01

    Full Text Available Las posibilidades productivas de la región, con escasas condi - ciones para las prácticas agrícolas pero adecuadas para la ganadería extensiva, predominantemente lanar, hicieron finalmente que la inser - ción patagónica se pensara dentro del mismo modelo de crecimiento “hacia afuera” delineado para el conjunto nacional sobre fines del siglo XIX y comienzos de XX. El único intento superador producido en ese período, aunque frustrado, lo constituyó el proyecto de desarro - llo patagónico elaborado por el Ministro de Obras Públicas del presi - dente Figueroa Alcorta, Ezequiel Ramos Mexía, concretado en la “Ley de Fomento de los Territorios Nacionales” nº 5.559 del año 1908. El ministro, hijo y nieto de estancieros bonaerenses, tenía una concep - ción amplia en materia de desarrollo económico y, en ese sentido, la Patagonia aparecía como el territorio adecuado para generar algunos cambios en un país que por entonces sólo se pensaba en términos agrícolas y pastoriles.

  13. Neighborhood effects on seed dispersal by frugivores: testing theory with a mistletoe-marsupial system in Patagonia.

    Science.gov (United States)

    Morales, Juan Manuel; Rivarola, María Daniela; Amico, Guillermo; Carlo, Tomás A

    2012-04-01

    The outcome of the dispersal process in zoochorous plants is largely determined by the behavior of frugivorous animals. Recent simulation studies have found that fruit removal rates and mean dispersal distances are strongly affected by fruiting plant neighborhoods. We empirically tested the effects of conspecific fruiting plant neighborhoods, crop sizes, and plant accessibility on fruit removal rates and seed dispersal distances of a mistletoe species exclusively dispersed by an arboreal marsupial in Northern Patagonia. Moreover, in this study, we overcome technical limitations in the empirical estimation of seed dispersal by using a novel 15N stable isotope enrichment technique together with Bayesian mixing models that allowed us to identify dispersed seeds from focal plants without the need of extensive genotyping. We found that, as predicted by theory, plants in denser neighborhoods had greater fruit removal and shorter mean dispersal distances than more isolated plants. Furthermore, the probability of dispersing seeds farther away decreased with neighborhood density. Larger crop sizes resulted in larger fruit removal rates and smaller probabilities of longer distance dispersal. The interplay between frugivore behavioral decisions and the spatial distribution of plants could have important consequences for plant spatial dynamics.

  14. MAMÍFEROS INVASORES EN LA PATAGONIA ARGENTINA: EL CONEJO SILVESTRE EUROPEO COMO CASO EMBLEMÁTICO

    Directory of Open Access Journals (Sweden)

    Never Antonio Bonino Vassallo

    2010-04-01

    Full Text Available Se brinda una reseña de los estudios biológicos y ecológicos realizados sobre el conejo silvestre europeo (Oryctolagus cuniculus, tal vez el más emblemático de los mamíferos exóticos introducidos en Argentina. En el sector continental argentino el conejo se encuentra establecido, y en proceso de dispersión, principalmente en las provincias de Mendoza y Neuquén (NO de la Patagonia. En esta región, el conejo ha demostrado tener un efecto negativo sobre la economía regional, especialmente en áreas ganaderas y en plantaciones comerciales de árboles frutales y maderables. No existen programas oficiales para controlar la dispersión geográfica y/o el impacto de esta especie exótica. La gente que se siente perjudicada por el conejo recurre a intentos individuales para controlar sus efectos negativos. Es necesario implementar monitoreos regulares de la dispersión del conejo para la detección temprana y el manejo de poblaciones recién establecidas; además, se requieren estudios comparativos tendientes a determinar los métodos más adecuados para controlar el impacto del conejo.

  15. A new species of Haplosporidium Caullery & Mesnil, 1899 in the marine false limpet Siphonaria lessonii (Gastropoda: Siphonariidae) from Patagonia.

    Science.gov (United States)

    Ituarte, Cristián; Bagnato, Estefanía; Siddall, Mark; Cremonte, Florencia

    2014-05-01

    A new species of Haplosporidium Caullery & Mesnil, 1899 parasitising the pulmonate gastropod Siphonaria lessonii Blainville in Patagonia, Argentina, is described based on morphological (scanning and transmission electron microscopy) and sequence (small subunit ribosomal RNA gene) data. Different stages of sporulation were observed as infections disseminated in the digestive gland. Haplosporidium patagon n. sp. is characterised by oval or slightly subquadrate spores with an operculum that is ornamented with numerous short digitiform projections of regular height, perpendicular to and covering its outer surface. The operculum diameter is slightly larger than the apical diameter of the spore. Neither the immature nor mature spores showed any kind of projections of the exosporoplasm or of the spore wall. Regarding phylogenetic affinities, the new species was recovered as sister to an undescribed species of Haplosporidium Caullery & Mesnil, 1899 from the polychaete family Syllidae Grube from Japanese waters. The morphological characters (ornamentation of the operculum, spore wall structure, shape and size of spores, and the lack of spore wall projections) corroborate it as an as yet undescribed species of Haplosporidium and the first for the phylum in marine gastropods of South America. Siphonaria lessonii is the only known host to date.

  16. Gelidivirgula Patagoniensis Gen. Nov., Sp. Nov., A Novel Psychrotolerant, Sporeforming Anaerobe Isolated from Magellanic Penguin Guano in Patagonia, Chile

    Science.gov (United States)

    Pikuta, Elena V.; Hoover, Richard B.; Marsic, Damien; Whitman, William B.; Tang, Jane; Krader, Paul

    2003-01-01

    A novel obligately anaerobic, psychrotrophic bacterium, strain PPP2(sup T), was isolated from guano of the Magellanic penguin (Spheniscus magellanicus) in Patagonia, Chile. The Gram-positive, sporeforming, straight rods with sizes 0.6-0.9 x 3.0-5.0 microns, are motile by peritrichous flagella. Growth was observed to occur within the pH range 6.0-9.5 (optimum pH x), and temperature range 2-28 C (optimum 20 C). The novel isolate does not require NaCl for growth, but is halotolerant and growth was observed between 0 and 7 % NaCl (w/v) with optimum at 0.5 % (w/v). The new isolate is a catalase negative chemoorganohetherotroph with fermentative metabolism and uses as substrates: peptone, Bacto-tryptone, Casamino acids, and yeast extract. The major metabolic products are: acetate, butyrate, ethanol, and hydrogen is a minor gas product.. Strain PPP2 was sensitive to ampicillin, tetracycline, chloramphenicol, rifampin, kanamycin, and gentamycin. The G+C content of the DNA is 43.6 mol%. On the basis of 16S rDNA gene sequences and phenotypic characteristics, it is proposed that the strain PPP2(sup T) (= ATCC BAA-755(sup T) = JSM ...(sup T)) is assigned to the new genus Gelidivirgula gen. nov., as a representative of the new species, Gelidivirgula patagonensis sp. nov.

  17. Salud y enfermedad en Patagonia Austral, líneas de análisis, problemas y perspectivas

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    Guichón, Ricardo Aníbal

    2005-01-01

    Full Text Available La dispersión de enfermedades durante el proceso de contacto europeo aborigen en Patagonia Austral es un tema complejo en el cual estamos comenzando a trabajar. Partiendo de algunas consideraciones generales sobre el proceso de ocupación humana en la región se analiza la información sobre: ¿Qué tipos de enfermedades actuaron en momentos pre y post contacto europeo aborigen? ¿Cuál es la muestra osteológica humana disponible y que información tiene asociada? ¿Dónde y cómo aparece el registro biológico humano? Asimismo se hace referencia a algunos avances en dos líneas de trabajo: tafonomía de restos humanos a partir del análisis de propiedades óseas intrínsecas y otra sobre Paleoparasitología. En el marco de proyectos de colaboración con arqueólogos, se señalan los trabajos iniciados en dos sitios: el primer asentamiento español en el estrecho de Magallanes (1584 y La Misión Salesiana "La Candelaria" de Río Grande, Tierra del Fuego. El desafió es coordinar esfuerzos entre bioantropólogos, biólogos, paleopatólogos, paleoparasitólogos, médicos, arqueólogos e historiadores.

  18. Persistence of a Mesozoic, non-therian mammalian lineage (Gondwanatheria) in the mid-Paleogene of Patagonia

    Science.gov (United States)

    Goin, Francisco J.; Tejedor, Marcelo F.; Chornogubsky, Laura; López, Guillermo M.; Gelfo, Javier N.; Bond, Mariano; Woodburne, Michael O.; Gurovich, Yamila; Reguero, Marcelo

    2012-06-01

    We describe two isolated molariforms recovered from early-middle Eocene (early Lutetian) levels of northwestern Patagonia, Argentina. Comparisons with major lineages of therian and non-therian mammals lead us to refer them to a new genus and species of Gondwanatheria (Allotheria). There is a single root supporting each tooth that is very short, wide, rounded, and covered by cementum; the steep sidewalls, lack of a neck between the crown and root, and the heavily worn stage in both molariforms suggest that they were of a protohypsodont type. Both teeth are strongly worn at their centers, all along their length, with the labial edge less worn than the lingual; they show strong transverse crests that alternate with lingual grooves. The protohypsodont aspect of the teeth, as well as the strong, transverse crests, are suggestive of sudamericid affinities; on the other hand, the thin enamel layer and the occlusal pattern formed by the crests and grooves shows more similarities to molariform teeth of the Ferugliotheriidae. The new taxon adds evidence regarding the (1) extensive radiation of the Gondwanatheria throughout the Southern Hemisphere, (2) persistence of several lineages well after the Cretaceous/Paleogene boundary, and (3) early evolution of hypsodont types among South American herbivorous mammals.

  19. Status of the names of some hydroid species (Cnidaria, Hydrozoa), described from the Atlantic coast of Patagonia.

    Science.gov (United States)

    Miranda, Thaís P; Cunha, Amanda F; Marques, Antonio C

    2016-09-29

    Thirty new species of benthic leptothecate hydroids were described and named from Patagonia in a 1991 PhD dissertation by Mohamed El Beshbeeshy. Although constituting nomina nuda under provisions of the International Code of Zoological Nomenclature (ICZN), the names of some species were used in several scientific publications between 1991 and 2011. In 2011, the dissertation of El Beshbeeshy was published in accordance with Article 8 of the ICZN. Several species-group names appearing in that work nevertheless fail to fully comply with certain articles of the code. The goal of this contribution is to review the nomenclatural availability of the names of those 30 new taxa, and to clearly establish the current status of El Beshbeeshy's material. Two of them were made available in 1999 as part of studies other than those of El Beshbeeshy, and correct authorship and date is here noted. Twenty-one of the nomina nuda were made available in a work published by El Beshbeeshy in 2011, although some constitute junior synonyms. Six of the new species-group names appearing in both the 1991 and 2011 works, established following a literature review of Patagonian species, were proposed without re-description, or designation of name-bearing types, or locations of such types. Most of them do not meet criteria of availability and remain nomina nuda. The status of each is discussed to avoid additional nomenclatural errors and continued taxonomic confusion.

  20. Contaminants in the southern tip of South America: Analysis of organochlorine compounds in feathers of avian scavengers from Argentinean Patagonia.

    Science.gov (United States)

    Martínez-López, E; Espín, S; Barbar, F; Lambertucci, S A; Gómez-Ramírez, P; García-Fernández, A J

    2015-05-01

    The aim of this study was to assess the exposure to organochlorine compounds (OC) in 91 primary wing feathers of avian scavengers, Turkey vulture (Cathartes aura), American black vulture (Coragyps atratus) and Southern crested caracaras (Polyborus plancus) from the southern tip of South America, in the Argentinean Patagonia. We analyzed for a series of OC including hexachlorocyclohexane (HCH) isomers, endosulfan, aldrin, dieldrin, endrin, dichlorodiphenyltrichloroethane (p,p'-DDT), dichlorodiphenyldichloroethane (p,p'-DDD), dichlorodiphenyldichloroethylene (p,p'-DDE), heptachlor and heptachlor-epoxide. This is the first study on OC in feathers of three terrestrial top carnivores from South America. OC concentrations found in the studied species were much higher than those found in feathers of raptors from Europe and Asia, which likely indicate their high use in the region, specifically in agriculture, and other possible uses of OC in this area. ∑HCH had the highest median concentration, followed by ∑Drins, ∑DDT, ∑Heptachlor, and ∑Endosulfan, similar to those reported in several food samples in Argentina. On the other hand, differences in OC profiles between species and areas may be related to feeding and migratory habits, as well as the molt period. Three individuals showed ∑DDT (DDT, DDD and DDE) concentrations in feathers related to sublethal effects. However, this comparison should be used with caution due to problems with extrapolating such data across tissues and species.

  1. Ñ irihuau: Explotación de hidrocarburos y conflicto social en las inmediaciones de Bariloche (Patagonia, Argentina

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    Guido Galafassi

    2014-06-01

    Full Text Available En el año 2008, el gobierno de la provincia de Río Negro (Patagonia, Argentina licitó y adjudicó a la Unión Transitoria de Empresas (ute YPF-Pluspetrol el área petrolera Ñirihuau para trabajos de exploración y eventual explotación de hidrocarburos. La iniciativa suscitó un importante proceso de movilización social, por cuanto el bloque concesionado lindaba con el Parque Nacional Nahuel Huapi y se ubicaba dentro de la reserva de biosfera Andino Norpatagónica. Asimismo, la zona es soporte de otras actividades económicas incompatibles con el proyecto y comprende territorios ancestrales reivindicados por comunidades indígenas mapuche. En el siguiente estudio de caso analizaremos el diseño y la implementación de esta política, focalizándonos en las peculiares características del área Ñirihuau y los cuestionamientos y estrategias seguidas por quienes se opusieron a la concesión. Hacia el final, pondremos este análisis en contexto, y lo relacionaremos con la situación de la industria hidrocarburífera argentina.

  2. Optical Flow Applied to Time-Lapse Image Series to Estimate Glacier Motion in the Southern Patagonia Ice Field

    Science.gov (United States)

    Lannutti, E.; Lenzano, M. G.; Toth, C.; Lenzano, L.; Rivera, A.

    2016-06-01

    In this work, we assessed the feasibility of using optical flow to obtain the motion estimation of a glacier. In general, former investigations used to detect glacier changes involve solutions that require repeated observations which are many times based on extensive field work. Taking into account glaciers are usually located in geographically complex and hard to access areas, deploying time-lapse imaging sensors, optical flow may provide an efficient solution at good spatial and temporal resolution to describe mass motion. Several studies in computer vision and image processing community have used this method to detect large displacements. Therefore, we carried out a test of the proposed Large Displacement Optical Flow method at the Viedma Glacier, located at South Patagonia Icefield, Argentina. We collected monoscopic terrestrial time-lapse imagery, acquired by a calibrated camera at every 24 hour from April 2014 until April 2015. A filter based on temporal correlation and RGB color discretization between the images was applied to minimize errors related to changes in lighting, shadows, clouds and snow. This selection allowed discarding images that do not follow a sequence of similarity. Our results show a flow field in the direction of the glacier movement with acceleration in the terminus. We analyzed the errors between image pairs, and the matching generally appears to be adequate, although some areas show random gross errors related to the presence of changes in lighting. The proposed technique allowed the determination of glacier motion during one year, providing accurate and reliable motion data for subsequent analysis.

  3. Redescription of Antarctophthirus microchir (Anoplura: Echinophthiriidae) from the South American sea lion, Otaria flavescens, from Patagonia, Argentina.

    Science.gov (United States)

    Leonardi, M Soledad; Crespo, Enrique A; Raga, Juan Antonio; Fernández, Mercedes

    2009-10-01

    Antarctophthirus microchir was originally described from Phocarctos hookeri on the basis of 1 female and 1 male only. We redescribe adults and describe, for the first time, the 3 nymphal stages from specimens collected from Otaria flavescens from Patagonia, using light and scanning electron microscopy. The present material can be distinguished from other Antarctophthirus species by the presence of a fringe of setae on the back of the head, only present in Antarctophthirus trichechi and Antarctophthirus callorhini. However, A. trichechi also possess a prominent proboscis with large hooks, and A. callorhini presents less abundant and nonuniform abdominal scales in shape and size. Other differential features of A. microchir are the pattern of ovoid and uniform scales and longitudinal grooves in the surface of spines. Nymphal stage 1 differs from 2 and 3 mainly by the absence of scales and thorax without ventral spines or hairs. Nymphal stages 2 and 3 may be distinguished by the disposition of the occipital apophyses. Antarctophthirus microchir has been reported from 5 sea lion species from both hemispheres. Considering the conservative morphology, and ecological and evolutionary features of sucking lice, we raise the question of whether A. microchir from different sea lion hosts may represent a complex of cryptic species.

  4. Population structure of the snail Buccinanops globulosum (Prosobranchia, Nassariidae) in San Matías Gulf, Patagonia Argentina: Isolated enclaves?

    Science.gov (United States)

    Narvarte, Maite; Willers, Valeria; Avaca, María Soledad; Echave, María Eugenia

    2008-10-01

    In San Matías Gulf (Patagonia, Argentina), Buccinanops globulosum is typically distributed in two different areas: the intertidal-subtidal zone of Playa Villarino, where conch length reaches up to 60 mm, and the inner channel of San Antonio Bay, where individuals are not larger than 30 mm. It is suggested that both populations of B. globulosum constitute independent enclaves adapted to the local conditions and with a different population structure. This comparative study focuses on the population structure, sex ratios, growth, and size at maturity at the two sites. The data collected reveal that the individuals in San Antonio ranged from 5 to 29 mm whereas those in Villarino ranged from 4 to 61 mm. It was also observed that in San Antonio Bay, generally males outnumbered females whereas exactly the opposite occurred in Villarino. In addition, females were larger and showed a faster growth than males in both study areas. The number of egg capsules on each female ranged from 8 to 25 in San Antonio Bay and from 5 to 66 in Villarino. Size at maturity of females in San Antonio Bay was estimated at 14.47 mm and maximum estimated length at 6 years old was 33 mm. The same parameters in the individuals from Villarino were 45 and 65 mm, respectively. The comparative analysis of the above-mentioned features poses the question of whether these two populations represent either different species or different forms of the same species.

  5. Crater lakes of the Pali Aike Volcanic Field as key sites for paleoclimatic and paleoecological reconstructions in southern Patagonia, Argentina

    Science.gov (United States)

    Zolitschka, Bernd; Schäbitz, Frank; Lücke, Andreas; Corbella, Hugo; Ercolano, Bettina; Fey, Michael; Haberzettl, Torsten; Janssen, Stephanie; Maidana, Nora; Mayr, Christoph; Ohlendorf, Christian; Oliva, Gabriel; Paez, Marta M.; Schleser, Gerhard H.; Soto, Julio; Tiberi, Pedro; Wille, Michael

    2006-07-01

    Sedimentary records from crater lakes are of major scientific interest because they provide continuous high-resolution climatic and environmental archives. From a limnogeological survey of crater lakes performed in the Pali Aike Volcanic Field (52°S, southeastern Patagonia, Santa Cruz, Argentina), two deep crater lakes have been recognized: Laguna Potrok Aike (100 m water depth) and Laguna Azul (56 m water depth). Physico-chemical analyses of these closed lake systems demonstrate that Laguna Azul has a dimictic and thermally stratified freshwater body, whereas Laguna Potrok Aike is a subsaline polymictic lake. Both have an oxygen-rich water column from top to bottom. Laguna Potrok Aike in particular is enriched in Na, P, and Cl. The morphometry suggests that Laguna Azul is of Holocene age, whereas the potential sediment infill of Laguna Potrok Aike may comprise 250 m to a mid-Pleistocene age (770 ka). Several aerial and subaquatic lake level terraces at Laguna Potrok Aike point to lake level fluctuations triggered by prior hydrological changes. Although fine-grained sediments of both lakes are not varied, they may eventually provide a detailed terrestrial record of past environmental and climatic variations for this southern mid-latitude region.

  6. Cambios en lagos y circulación fluvial vinculados al calentamiento climático del Pleistoceno tardío-Holoceno temprano en Patagonia e isla 25 de mayo, islas Shetland del Sur, Antártida Changes in lakes and fluvial circulationlinked to climate warming in Late Pleistocene - Early Holocene in Patagonia and 25 de Mayo Island, Shetland del Sur Islands, Antarctica

    Directory of Open Access Journals (Sweden)

    R.A. del Valle

    2007-12-01

    Full Text Available El calentamiento clim ático que afectó a la Patagonia en el Pleistoceno tardío-Holoceno temprano produjo cambios en la morfología del paisaje, incluyendo la génesis, desarrollo y desintegración de grandes lagos al este de los Andes. Hasta entonces, los glaciares y sus morenas formaban diques naturales que embalsaron las aguas de deshielo y mantenían alto el nivel de las aguas en los grandes paleolagos. Posteriormente, la migración hacia el sur de la mejoría climática ocasionó la progresiva fusión del campo de hielo regional, y las morenas fueron cortadas por la erosión fluvial, cuando el calentamiento climático impactó plenamente en la región. El proceso afectó a la región de norte a sur en tiempos diferentes: 1 hace c. 13.200 años en el norte, 2 durante la transición Pleistoceno/Holoceno en la parte central, y 3 finalmente, en Tierra del Fuego hace unos 7.800 años. El rápido retroceso de los glaciares produjo el desalojo de los valles andinos a ambos lados de la cordillera, lo cual abrió cauces fluviales que atraviesan la cordillera desde entonces, inaugurando el drenaje hacia el océano Pacífico de grandes lagos glaciales que existían al oriente de los Andes. Esto resultó en el rápido descenso del nivel de los paleolagos. Un proceso similar ocurrió en las islas Shetland del Sur (Antártida hace unos 6.000 años.The climate warming that affected Patagonia region during late Pleistocene-early Holocene times produced changes in landscape morphology, including the formation, development, breakdown and disintegration of big lakes at the eastern side of Andes. Before these times, glaciers and their moraines formed natural dams that maintained a high water level in large paleolakes. The subsequent southward migration of climate amelioration produced the melting of the regional ice field, and moraines were cut by fluvial erosion, when climate warming strongly impacted in the region. The process occurred in the region from

  7. Análisis del gradiente edáfico en la región Andinopatagónica Analysis of soil gradient in Andean Patagonia Region

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    Juan José Gaitán

    2007-07-01

    Full Text Available Se analizaron las relaciones entre la ubicación geográfica, precipitación media anual y nueve variables edáficas de 95 perfiles de suelos de origen volcánico distribuidos a lo largo de la región Andina de las provincias de Neuquén, Río Negro y Chubut. Con las variables edáficas correspondientes a dos profundidades (0-20 cm y 30-60 cm se realizó un análisis de cluster que permitió agrupar a los perfiles en cinco grupos principales. Se realizó un análisis de componentes principales y se observó que los grupos se diferenciaron a lo largo del eje 1. Este eje se relaciona con la longitud. Desde los suelos de régimen xérico de estepa ubicados en el este de la región hacia los suelos de régimen údico de bosque ubicados en el oeste, se incrementa el pH (NaF, la concentración de carbono orgánico y la capacidad de retención hídrica y disminuye, el pH (H2O, el pH (KCl y la densidad aparente.The relationships among location, mean annual precipitation and nine edaphic variables were studied for 95 profiles of volcanic soils throughout the Andean Region of the provinces of Neuquen, Rio Negro and Chubut. A cluster analysis conducted with the edaphic variables at two depths (0-20 cm and 30-60 cm indicated five main groups. Principal component analysis (PCA allowed to differentiate the groups for the axis 1. This axis was positively related to longitude, indicating an increase of pH (NaF, organic C and water retention capacity, and a decrease of pH (H2O, pH (KCl and bulk density from the xeric steppe soils at east to the udic forest soils at west.

  8. FRUPAT: A Tool to Quantify Inputs and Outputs of Patagonian Fruit Production Systems

    NARCIS (Netherlands)

    Cittadini, E.D.; Keulen, van H.; Peri, P.L.

    2006-01-01

    A software called FRUPAT was developed for calculating input and output coefficients (Technical Coefficients) of fruit production systems in South Patagonia. FRUPAT combined locations (Río Chubut valley; Sarmiento valley; Los Antiguos valley; Río Chico valley), edaphic environment (good quality soil

  9. In situ impact of solar ultraviolet radiation on photosynthesis and DNA in temperate marine phytoplankton

    NARCIS (Netherlands)

    Helbling, E.W; Buma, A.G.J.; de Boer, M.K.; Villafane, V

    2001-01-01

    In situ experiments were conducted at various depths in the water column to determine the impact of solar UV radiation (280 to 400 nm) upon photosynthesis and DNA of natural phytoplankton assemblages from mid-latitudes of Patagonia (Bahia Bustamante, Chubut, Argentina; 45 degreesS, 66.5 degreesW). T

  10. Redefinición estratigráfica del grupo Río Chico (Paleógeno Inferior, en el norte de la cuenca del golfo San Jorge, Chubut Stratigraphic redefinition of Río Chico Group (Early Paleogene in the north of the Golfo San Jorge basin, Chubut

    Directory of Open Access Journals (Sweden)

    María Sol Raigemborn

    2010-10-01

    Full Text Available El Grupo Río Chico (Paleoceno Superior-Eoceno Medio, de origen continental y aflorante en la cuenca del Golfo San Jorge, aun no cuenta con un esquema litoestratigráfico adecuado que contemple las variaciones y relaciones espaciales de sus unidades integrantes. En este trabajo, restringido arealmente al norte de la cuenca, se redefinen sus cuatro formaciones que de base a techo son: Las Violetas, Peñas Coloradas, Las Flores y Koluel-Kaike. La relación inferior del grupo con la Formación Salamanca es de tipo transicional y se resuelve en un intervalo estratigráfico denominado en este trabajo niveles transicionales. La Formación Las Violetas se circunscribe al centro del área de estudio, borde norte de la cuenca, donde se manifiesta una posible relación de lateralidad con la Formación Peñas Coloradas. Esta última muestra un importante desarrollo en la zona costera y occidental, sin aflorar en el área central de estudio. La Formación Las Flores alcanza su mayor espesor en la zona central (facies más gruesas y disminuye hacia el este y oeste (facies más finas. La Formación Koluel-Kaike posee sus facies típicas y mayores espesores hacia el oeste, mientras que hacia el centro y este se acuña hasta desaparecer en el borde norte de la cuenca. La relación superior de esta última unidad con la suprayacente Formación Sarmiento es de tipo transicional.The Río Chico Group (Late Paleocene-Middle Eocene, which is continental in origin and outcrop in Golfo San Jorge basin, has not got a suitable lithostratigraphic scheme yet which considers variations and spatial relationships of its internal units. In this paper, restricted to the north of the basin, four formations are redefined from base to top: Las Violetas, Peñas Coloradas, Las Flores and Koluel-Kaike. The lower relationship of this group with Salamanca Formation is transitional and it is resolved in a stratigraphic interval called in this paper transitional levels. Las Violetas

  11. The role of stand composition on pre-dispersal seed predation in Austrocedrus chilensis (Cupressaceae in north west Patagonia El rol de la composición del bosque sobre la depredación predispersiva de semillas en Austrocedrus chilensis (Cupressaceae en el noroeste de la Patagonia

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    JOSÉ M VILLACIDE

    2008-09-01

    Full Text Available We studied the variability of pre-dispersal seed predation by insects on Austrocedrus chilensis (Cupressaceae. This is a dioecious conifer endemic to southern South America (central Chile and the Chilean Argentinean Patagonia that grows naturally in pure and mixed stands, typically in association with broadleaved Nothofagus species. Seeds are attacked while still inside the cones, mainly by larvae of Nanodacna austrocedrella (Lepidoptera: Elachistidae. Our working hypothesis was that observed variations in pre-dispersal seed damage levels were related to forest stand composition, specifically to the relative abundance of A. chilensis versus accompanying Nothofagus species. We compared seed predation levels in six pairs of sites using a block design which included a mixed and a pure stand for each paired site. At each site, we manually collected 50 closed seed cones from each of five neighbouring adult trees of A. chilensis. Pre-dispersal seed damage was highly variable among trees and sites, with values ranging between 16.7 to 73.0 % of seeds damaged. We found significant differences in predation rates among stands differing in canopy composition. In mixed stands, with Nothofagus, the proportion of seeds attacked was always greater than that observed in the paired pure A. chilensis stand. We showed that canopy composition influenced the level of pre-dispersal seed predation by insects, supporting the hypothesis that damage increases in mixed stands. Our study is the first to present data on variations of pre-dispersal seed predation in A. chilensis at a large spatial scale, examining the effects of forest type. This information may be useful in planning for commercial A. chilensis seed harvesting, as well as for the conservation this endemic conifer.Estudiamos la variabilidad en la depredación predispersiva de semillas por insectos en Austrocedrus chilensis (D. Don Pie. Serm. & Bizzarri (Cupressaceae. Esta especie es una conifera dioica end

  12. From Ecuador to Patagonia: Andean deformation from InSAR 1992-2007

    Science.gov (United States)

    Pritchard, M. E.; Finnegan, N. J.

    2007-12-01

    We use Interferometric Synthetic Aperture Radar (InSAR) observations from 6 satellites (ERS-1, ERS-2, ENVISAT, RADARSAT, ALOS, and JERS-1) along with published GPS displacements to constrain the myriad deformational processes in the central and southern Andes between 1992-2007. In this contribution, we review the types of deformation that are occurring (volcanoes, earthquakes, post-seismic and inter-seismic deformation, glaciers, groundwater, and anthropogenic processes) and present new observations and models of these processes. In the central Andes, InSAR observations have been possible in all seasons and have documented numerous sources of deformation: at least 7 volcanic areas, more than a dozen earthquakes (5 oil production in the San Jorge basin, as well as motion of glaciers at the Northern and Southern Patagonian Icefields. Preliminary L-band InSAR data from ALOS indicates great potential for further illuminating deformational processes in the southern Andes.

  13. Did Patagonia collide against Gondwana in the Late Paleozoic? Some Insights From Magnetic Fabrics of Granitoids in the North Patagonian Massif.

    Science.gov (United States)

    Rapalini, A. E.; Lopez de Luchi, M. G.; Tomezzoli, R. N.

    2008-05-01

    The Paleozoic tectonic evolution of Patagonia has been a matter of much debate in the last two decades. There is no consensus on whether the North Patagonian Massif (NPM) was accreted by a frontal collision to Gondwana in the Late Paleozoic or if it shared a similar paleotectonic evolution with other Gondwana blocks during the Paleozoic. Different geologic, geochronologic, geophysical and structural data have been interpreted either as supporting or refuting the collisional model. Paleomagnetic data obtained so far is consistent with an authochtonous evolution since the Devonian, but it does not rule out relative displacements of up to 1500 km between Patagonia and Gondwana.Therefore, a Late Paleozoic frontal collision cannot be definitely ruled out on the basis of paleomagnetic data alone. As part of a muldisciplinary research project a magnetic fabric study, by means of the anisotropy of magnetic susceptibility (AMS), was carried out on Late Paleozoic granitoids exposed in northeastern NPM. Two main composite units were studied, the highly to variably foliated Yaminue Complex, poorly dated as Late Carboniferous and ranging in composition from tonalite to leuco-granite, and the much less deformed granodiorites to monzoganites of the Early Permian (283 Ma) Navarrete complex. While the former is composed of both ferro and paramagnetic units, with a dominance of the latter; the Navarrete plutons are basically ferromagnetic. Directional and scalar AMS results joined with meso and microstructural studies permitted the characterization of the deformational and magmatic fabric of the different units. An evolutionary picture of the succesive intrusive events in NPM emerged which confirms an important NNE-SSW contractional event associated with intrusion of the different units that compose the Yaminue Complex. This event ended before the intrusion of the Navarrete Complex, which is governed by a different stress regime. Our results fit the hypothesis of a collisional event

  14. Afinidades biológicas entre muestras tardías del norte de Patagonia y regiones vecinas establecidas mediante rasgos no métricos craneofaciales

    Directory of Open Access Journals (Sweden)

    Del Papa, Mariano C.

    2005-01-01

    Full Text Available En el marco de una investigación orientada a evaluar la dinámica evolutiva de las poblaciones del norte de Patagonia durante el Holoceno Tardío, se están relevando en la actualidad diversos indicadores, entre los cuales se cuentan los rasgos no métricos. El objetivo de este trabajo es presentar los resultados parciales obtenidos a partir del análisis de variables no métricas craneofaciales en muestras del norte de Patagonia y áreas vecinas (sur de Patagonia, sur de Mendoza y S.E. de la Región Pampeana. Se analizaron individuos adultos (i.e. >20 años al momento de morir de ambos sexos. Como criterio para separar a las muestras cronológicamente, se utilizó la presencia y tipo de deformación craneana artificial, un indicador temporal eficiente en una escala regional y supraregional. Para la estimación de las distancias biológicas, se realizaron análisis de correspondencia (AC y de componentes principales (CP sobre distancias euclidianas y cálculo de la medida media de divergencia de Smith (MMD. En términos globales, los resultados obtenidos indican que las submuestras procedentes del valle inferior del Río Negro presentan los mayores grados de afinidad, sugiriendo una mayor continuidad en el poblamiento regional en relación con otras áreas.

  15. Aportes de los "intermediarios culturales" en la conformación de los paisajes fronterizos del norte de la patagonia a fines del siglo XVIII

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    Laura Aylén Enrique

    2012-12-01

    Full Text Available A fines del siglo XVIII la Corona española envió expedicionarios a reconocer el norte de la Patagonia, un territorio dominado por grupos indígenas pero de importancia estratégica para los hispanocriollos. Los funcionarios del Virreinato del Río de la Plata que llevaron a cabo dichas exploraciones registraron sus impresiones en diarios de viaje que analizamos con el objetivo de examinar los modos en que el paisaje norpatagónico fue construido simbólicamente. Consideramos que dicho paisaje se constituyó en base a las luchas desplegadas tanto por hispanocriollos como por indígenas buscando dar sentido al territorio. Sostenemos que, en este contexto, los personajes que se desempeñaban como intérpretes ejercían un rol fundamental en la configuración del territorio, dada la ambigüedad de su posición de intermediarios en las relaciones interétnicas.By late eighteen century the Spanish Crown sent expedition to recognize north Patagonia, a territory dominated by indigenous groups but also of strategic importance to the Hispanic-Creole population. River Plate Viceroyalty officials in charge of the above-mentioned explorations registered their impressions in travel diaries that are thoroughly analyzed in order to discover the ways this landscape of north Patagonia was symbolically constructed. We think this mestizo landscape was the result of struggles maintained between Hispanic-Creoles and natives searching to convey meaning to the territory. Moreover, we state that in this context, the actors who served as interpreters developed a key role in the territorial configuration, given the ambiguity of their position as intermediaries of interethnic relations.

  16. FLUCTUACIONES DE LA PALEOPRODUCTIVIDAD EN LA CUENCA DEL ESTRECHO DE MAGALLANES, SU RELACION CON LA TRANSGRESION MARINA Y LOS CAMBIOS CLIMATICOS EN PATAGONIA SUR

    OpenAIRE

    ARACENA PEREZ, CLAUDIA MILENI; ARACENA PEREZ; CLAUDIA MILENI

    2011-01-01

    En el marco del cambio climático global, estudios acerca de la evolución ambiental de cuencas sedimentarias distribuidas en sectores aún cubiertos por campos glaciares constituyen investigaciones de gran relevancia científica. Patagonia Sur es un sistema único donde los efectos de la erosión mecánica y química que produce el ciclo hidrológico modelan el paisaje a un nivel altamente complejo. Junto con lo anterior, la bioproductividad de este sistema está principalmente controlada por la...

  17. Memorias Silenciadas y patrimonios ausentes en el Museo Histórico de El Hoyo, Comarca Andina del Paralelo 42, Patagonia Argentina

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    CAROLINA CRESPO

    2014-08-01

    Full Text Available This article analyzes the silences and absent heritage in the exhibition at the Historical Museum in the town of El Hoyo in Patagonia (Argentina. In particular, it examines the widespread silences about indigenous peoples and certain issues and relationships, while attempting to reveal the mechanisms by which the institution gave shape to these absences. We approach the analysis of these silencings as productive resources through which systems of belonging and differentiation, stratification and territorialization, are configured and transmitted, revealing relations of power and structuring the possible field of action.

  18. Entre el "deber" y el "derecho": patrimonio arqueológico y obligaciones sociales en Patagonia Argentina Among "duty" and "rights": Archaeological heritage and social obligations in Argentine

    Directory of Open Access Journals (Sweden)

    Carolina Crespo

    2006-12-01

    Full Text Available En años recientes, los restos arqueológicos de varias provincias de la Patagonia han sido legislados bajo la categoría de "patrimonio cultural" de las mismas, regulándose su uso científico, cultural y, en ciertos casos, turístico. Sin embargo, más allá de los comportamientos reglados por el texto legal coexiste toda una serie de comportamientos y lazos sociales que se rigen bajo otras reglas o principios que trascienden el marco normativo. Motiva así, a este artículo, analizar los intercambios sociales que se entretejen por fuera del andamiaje institucional y jurídico alrededor de los bienes arqueológicos, específicamente del arte rupestre, en una ciudad de Patagonia. La importancia del análisis reside en el tipo de relaciones que se actualiza hoy alrededor de este patrimonio, el desplazamiento de sentidos que éstas impulsan sobre este bien y los efectos que generan en la gestión del mismo. El examen de las prestaciones y contraprestaciones, esto es, de las obligaciones mutuas que expresan, pretende servir como un ejemplo de la resignificación que en los últimos años adquieren los bienes arqueológicos y, específicamente el arte rupestre en la Patagonia Argentina, así como de las complejidades que reviste su gestión.In recent years the archaeological remains from several Patagonian provinces were legislated under the category of "cultural heritage," regulating their scientific, cultural and, in some cases, touristic use. Nevertheless, beyond the behaviors regulated by the legal text an entire series of behaviors and social connections coexist that is governed by other rules or principles which transcend the normative framework. As such, the goal of this paper is to analyze the social exchanges that are woven together beyond the institutional and legal scaffolding erected around archaeological goods - specifically rock art - in a Patagonian city. The relevance of the analysis lies in the type of relationships that are now

  19. A photo-identification catalogue of bottlenose dolphins (Tursiops truncatus) in Northeast Patagonia, Argentina: A tool for the conservation of the species

    OpenAIRE

    Vermeulen, Els; Cammareri, Alejandro; Failla, Mauricio

    2008-01-01

    A photo-identification study of bottlenose dolphins (Tursiops truncatus) was performed in the northern Gulf of San Matías, Patagonia Argentina, during the period 2006-2008. In total, 199 surveys were conducted with an average observation effort of 4.2h (SD=1.5) per survey. These surveys resulted in a total observation effort of 824.7h of which 105.7h was spend with 158 dolphin groups. Over 12,500 pictures were analysed using the automatic identification systems FinEx and FinMatch ...

  20. Diseño de obras de control de aluviones basada en simulación de procesos hidrológicos torrenciales en cuencas de la Patagonia

    OpenAIRE

    Dufilho,Ana Cecilia; Horne,Federico; Navedo,Rodrigo; Polla,Gabriela

    2001-01-01

    Fenómenos climáticos torrenciales que producen aluviones y grandes movimientos de sedimentos (bajo distintas formas) son muy frecuentes en la Patagonia Argentina. Los estudios para el diseño de obras de control se realizan en general, a través de fórmulas empíricas sin verificar su aptitud a las condiciones patagónicas. En el presente trabajo se utilizan modelos matemáticos sencillos para la simulación hidrológica de crecidas en cuencas con escasa información hidrometeorológica y nula instrum...

  1. Abundance estimates of southern right whales (Eubalaena australis) in Bahía San Antonio, Patagonia, Argentina

    OpenAIRE

    Vermeulen, E

    2013-01-01

    The abundance of southern right whales (Eubalaena australis) was estimated by the means of aerial line-transect surveys for the area of Bahía San Antonio, a bay located in the north-western region of the San Matías Gulf (40°50’S 64°50’W), Rio Negro, Patagonia Argentina. In total, seven aerial surveys were conducted in the first week of August and September 2009, September, October and November 2010, and August, September 2011. Survey effort equalled a total flight time of 12.4h, during which ...

  2. Primer registro de Naupactus ruizi (Coleoptera: Curculionoidea asociado con Pinus ponderosa (Gymnospermae: Pinaceae en Patagonia First record of Naupactus ruizi (Coleoptera: Curculionoidea associated to Pinus ponderosa (Gymnospermae: Pinaceae in Patagonia

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    Cecilia A. Gómez

    2006-07-01

    Full Text Available Naupactus ruizi (Brèthes es un gorgojo de rostro corto, distribuido en la Argentina y Chile, que habita en ambientes áridos asociado con vegetación xerofítica y alcanza el rango más austral entre los miembros de la tribu Naupactini. Un relevamiento de insectos y de patógenos como plagas potenciales, realizado durante el 2005 en plantaciones de Pinus spp. en la Patagonia andina argentina, resultó en el hallazgo de adultos de N. ruizi que se alimentaban de acículas de Pinus ponderosa Dougl. ex Laws. Este hallazgo es sorprendente dado que las especies de Naupactini, consumen casi exclusivamente angiospermas. Interpretamos que el cambio de huésped, habría ocurrido como consecuencia de una colonización reciente favorecida por la amplia distribución geográfica del gorgojo y su capacidad para sobrevivir en hábitats marginales, donde probablemente las plantas nativas son escasas y el nuevo huésped presenta una gran abundancia local.Naupactus ruizi (Brèthes is a broad-nosed weevil recorded from Argentina and Chile , that inhabits arid environments with xerophitic vegetation and reaches the southern most distribution of the tribe Naupactini. A survey of potential insect pests and pathogens of plantations of Pinus spp. and other forest species, conducted during 2005 in Argentinean Patagonian Andean forestations, allowed to find N. ruizi feeding on pine needles of Pinus ponderosa Dougl. ex Laws. This finding was unexpected, since species of Naupactini consume almost exclusively angiosperms. We interpret that the new host association may represent a recent host shift, probably facilitated by the broad range of the weevil, its capacity to survive in marginal habitats where natural hosts are scarce, and the local abundance of the new host.

  3. Bajada de rahue, province of neuquen, Argentina: an interstadial deposit in northern Patagonia

    Science.gov (United States)

    Markgraf, Vera; Bradbury, J.P.; Fernandez, J.

    1986-01-01

    Pollen and diatom analyses of a radiocarbon dated lacustrine section in the temperate Andean region of Argentina (Rahue, Province Neuquen) suggest interglacial type climatic conditions between 27,000 and 33,000 yr B.P., with environments that resemble the modern conditions at the locality. This finding correlates with a woodland record from central Chile, interpreted as reflecting conditions substantially warmer and drier prior to 27,000 yr B.P. than during the following full-glacial period. It also appears to relate to the global paleoclimatic scheme derived from deep-sea records, suggesting interhemispheric synchroneity of such broad-scale palaeoclimatic phases. ?? 1986.

  4. Central line infections - hospitals

    Science.gov (United States)

    ... infection; Central venous catheter - infection; CVC - infection; Central venous device - infection; Infection control - central line infection; Nosocomial infection - central line infection; Hospital acquired ...

  5. Titanium and oxygen isotope diffusion in quartz-phenocrysts from a Jurassic rhyolite, Chon Aike Province (Fitz Roy, Patagonia)

    Science.gov (United States)

    Seitz, S.; Putlitz, B.; Baumgartner, L. P.; Escrig, S.; Meibom, A.; Leresche, S.; Vennemann, T. W.

    2014-12-01

    The volcanic El Quemado Complex was deposited during the breakup of Gondwana during the Middle and Late Jurassic. It is part of a large silicic igneous province, which includes the Chon Aike Province in Southern Patagonia and related rocks from the Antarctic Peninsula [1]. The Complex consists of rhyolitic and dacitic ignimbrites and air-fall tuffs, intercalated with andesitic to rhyolitic lava flows. New LA-ICPMS U/Pb-dates of zircons from the Fitz Roy area yield ages between 148 and 153Ma. No inherited zircons were found, suggesting that the temperature of 850°C calculated from zircon saturation is a minimum temperature. Lava flows are typically rich in quartz phenocrysts, which preserved magmatic trace element zoning, as revealed by cathodoluminescence (CL): light cores are surrounded by several darker and lighter zones towards the rim. The δ18O-values for quartz of between 11 to 14 ‰ are compatible with a crustal source for the magma and the SIMS analyses of phenocrysts reveal no zoning in O-isotope compositions. High-resolution Ti-profiles were obtained by NanoSIMS with a beam size of ~200 nm and a minimum step size of ~120 nm. Several lines perpendicular to the magmatic zoning of the quartz-phenocrysts were measured. The profiles show sharp changes in the 48Ti/29Si-ratio over a distance of 5 μm, which correlate with CL-intensity changes. The profiles can be used for diffusion chronometry. The distances obtained from NanoSIMS profiles were used to calculate maximum diffusional relaxation times. Assuming a step function as initial condition and extrusion temperatures from zircon saturation of 850°C, we obtain a maximum residence time for the quartz-phenocrysts of 3.5 years. [1] Pankhurst R.J., Riley T.R., Fanning C.M., Kelley S.P., 2000. J. Pet., 41, 605-625.

  6. Exploring the diversity and antimicrobial potential of marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile

    Directory of Open Access Journals (Sweden)

    Agustina Undabarrena

    2016-07-01

    Full Text Available Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%, PKS I (18% and PKS II (73%.Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds.

  7. Trichococcus Patagoniensis sp. nov., a Facultative Anaerobe that grows at -5 C, Isolated from Penguin Guano in Chilean Patagonia

    Science.gov (United States)

    Pikuta, Elena V.; Hoover, Richard B.; Bej, Asim K.; Marsic, Damien; Whitman, William B.; Krader, Paul E.; Tang, Jane

    2006-01-01

    A novel, extremely psychrotolerant, facultative anaerobe, strain PmagGl(sup T), was isolated from guano of Magellanic penguins (Spheniscus magellanicus) collected in Chilean Patagonia. Gram-variable, motile cocci with a diameter of 1.3-2.0 micrometers were observed singularly or in pairs, short chains and irregular conglomerates. Growth occurred within the pH range 6.0-10.0, with optimum growth at pH 8.5. The temperature range for growth of the novel isolate was from -5 to 35 C, with optimum growth at 28-30 C. Strain PmagG1(sup T) did not require NaCl, as growth was observed in the presence of 0-6.5% NaCl with optimum growth at 0.5% (w/v). Strain PmagGl(sup T) was a catalase-negative chemo-organoheterotroph that used sugars and some organic acids as substrates. The metabolic end products were lactate, formate, acetate, ethanol and Con. Strain PmagG1(sup T) was sensitive to ampicillin, tetracycline, chloramphenicol, rifampicin, kanamycin and gentamicin. The G+C content of its genomic DNA was 45.8 mol%. 16S rRNA gene sequence analysis showed 100 % similarity of strain PmagG1(sup T) with Trichococcus collinsii ATCC BAA-296(sup T), but DNA-DNA hybridization between them demonstrated relatedness values of less than 45 plus or minus 1%. Another phylogenetically closely related species, Trichococcus pasteurii, showed 99.85 % similarity by 16s rRNA sequencing and DNA-DNA hybridization showed relatedness values of 47 plus or minus 1.5%. Based on genotypic and phenotypic characteristics, the novel species Trichococcus patagoniensis sp. nov. is proposed, with strain PmagG1(sup T) (=ATCC BAA-756(sup T)=JCM 12176(sup T)=CIP 108035(sup T)) as the type strain.

  8. Análisis de redes de parentesco y alianza entre caciques mapuches y tehuelches. Patagonia septentrional, siglo XIX

    Directory of Open Access Journals (Sweden)

    Julio Esteban Vezub

    2016-06-01

    Full Text Available Se revisita la historia política de uno los linajes de caciques más relevantes del norte de la Patagonia durante la expansión del estado nacional argentino de la segunda mitad del siglo XIX. Se vuelve sobre la heterogeneidad de fuentes (cartas de caciques, informes de autoridades y viajeros, listados de tropa indígena, etc. que ya había sido tratada con un método histórico narrativo. En esta ocasión se coteja este corpus con el Análisis de Redes Sociales (ARS, y los Sistemas de Información Geográfica (SIG, a los fines de interpretar los cambios de la topología relacional indígena y criolla en el contexto de emergencia del estado. Este objetivo se resuelve mediante la elaboración de grafos que representan la evolución de las redes parentales, y la estructura de poder indígena, ante una serie de eventos críticos entre 1856 y 1883. La hipótesis principal es que los linajes mapuches y tehuelches dieron el formato para la construcción de alianzas y filiaciones, las que tuvieron un carácter principalmente político por sobre los factores étnicos o de sangre. La experimentación destaca la importancia de combinar el análisis morfológico y estructural que permite el análisis de redes con la singularidad del comportamiento histórico de los actores

  9. U-Th and 10Be constraints on sediment recycling in proglacial settings, Lago Buenos Aires, Patagonia

    Science.gov (United States)

    Cogez, Antoine; Herman, Frédéric; Pelt, Eric; Norton, Kevin; Darvill, Christopher; Christl, Marcus; Morvan, Gilles; Reuschlé, Thierry; Chabaux, François

    2016-04-01

    The sedimentary cycle includes the formation by erosion of rocks, transport and deposition. While erosion and deposition can be documented, the history of sediments between the time it is extracted from the rocks and ultimately deposited into basins remains a major challenge. However, the mechanism of transfer and alteration of the sediments during transport plays a key role in the evolution of basins, feedbacks between erosion and climate, and glacial-interglacial variability of sediment transport and weathering. This is particularly true in proglacial settings because large overdeepenings, in particular, are potential sediment traps for which the efficiency at evacuating those sediments is largely unknown. The Lago Buenos Aires moraines in Patagonia are particularly interesting because they are imbricated from the older in the outer part to the younger in the inner part of the system. We sampled fine grained sediments from these moraines and measured U-Th isotopes in the 4-50 μm silicate fraction. Deposition ages were refined using 10Be exposure ages. We show first that the comminution ages model can be improved by measuring also Th isotopes, from which weathering rates can be deduced. Moreover we show from our data that there is a time lag of 300 kyr on average between erosion and deposition in the moraine. This could be attributed to the long residence time of sediments in the lake overdeepening. This conclusion raises perspectives about the transport times and dynamic of the sediments during a whole sedimentary cycle, and the subsequent effect on weathering. This conclusion could also contradict some assumptions commonly made for our erosion rates/sediment fluxes reconstructions based on river sediments analysis, in recently deglaciated catchments.

  10. Bioindication of volatile elements emission by the Puyehue-Cordón Caulle (North Patagonia) volcanic event in 2011.

    Science.gov (United States)

    Bubach, Débora; Pérez Catán, Soledad; Arribére, María; Guevara, Sergio Ribeiro

    2012-07-01

    The emission of volatile pollutants from the volcanic eruption of the Puyehue-Cordón Caulle complex (North Patagonia Andean Range) that started in June 4th, 2011, was investigated by bioindication means with the epyphytic fruticose lichen Usnea sp. The elemental composition of pooled samples made up with 10 lichen thalli were analysed by Instrumental Neutron Activation Analysis. Eleven sampling sites were selected within the impacted region at different distance from the volcanic source. Five sites were selected as they were already sampled in a previous study prior to the eruption. Two other new sampling sites were selected from outside the impacted zone to provide non-impacted baseline sites. The elements associated with the lichen incorporation of particulate matter (PM) of geological origin were identified by linear correlation with a geochemical tracer (Sm concentrations). The elements associated with PM uptake were Ce, Eu, Fe, Hf, La, Lu, Na, Nd, Sb, Sc, Se, Ta, Tb, Th, U, and Yb. Arsenic and Cs concentrations showed contributions exceeding the PM fraction in sites near the volcanic centre, also higher than the baseline concentrations, which could be associated with permanent emissions from the geothermal system of the Puyehue-Cordón Caulle complex. The lichen concentrations of Ba, Ca, Co, Hg, K, Rb, Sr, and Zn were not associated with the PM, not showing higher concentrations in the sites nearby the volcanic source or respect to the baseline values either. Therefore, there is no indication of the emission of volatile forms of these elements in the lichen records. The lichen records only identified Br volatile emissions associated with the Puyehue-Cordón Caulle complex eruption in 2011.

  11. POLÍTICAS IMPERIALES Y RIESGOS DE APROPIACIÓN DE LOS RECURSOS NATURALES: EL CASO DEL AGUA EN PATAGONIA

    Directory of Open Access Journals (Sweden)

    Gerardo M. de Jong

    2005-12-01

    Full Text Available El agua, como todo recurso estratégico, es apetecido por las grandes potencias dadas sus condiciones de escasez. Mucho se ha hablado ya (aunque nunca es suficien­te acerca del acuífero Guaraní y la indudables políticas de entrega de este recurso capaz de cubrir el consumo mundial de agua potable en los próximos 200 años; por lo contrario, poco se ha hablado de los recursos hídricos superficiales, subterráneos y sólidos de la Patagonia. Para poder contextúalizar el problema es necesario ubicarse en la dimensión de las fuerzas que actúan en relación al manejo de los recursos del planeta. El control de los excedentes a escala mundial requiere también de un consecuente control de los recursos naturales, de la tecnología y de la innovación tecnológica a esa escala, donde el espacio (ámbito de localización de los apetecidos recursos naturales acrecienta día a día sus rasgos comunes en función de ciertos estilos dominantes de tecnología que aseguran una modalidad de control de los excedentes generados a partir de la puesta en valor de la dotación de recursos que la naturaleza ha brindado a cada región. Esto exige el control del acceso a la extracción de la riqueza generada mediante el control de los recursos disponibles, los que seguramente serán explotados con modalidades extractivas degradantes propias de la apetencia propias de la crisis estructural de la producción capitalista a escala mundial.

  12. Exploring the Diversity and Antimicrobial Potential of Marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile

    Science.gov (United States)

    Undabarrena, Agustina; Beltrametti, Fabrizio; Claverías, Fernanda P.; González, Myriam; Moore, Edward R. B.; Seeger, Michael; Cámara, Beatriz

    2016-01-01

    Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although, Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae, and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera) was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus, and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium, and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%), PKS I (18%), and PKS II (73%). Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds. PMID:27486455

  13. FRAGMENTACIÓN URBANA Y ASOCIACIONES VECINALES EN SAN CARLOS DE BARILOCHE, PATAGONIA - ARGENTINA (1983-2015

    Directory of Open Access Journals (Sweden)

    Brenda Matossian

    2016-01-01

    Full Text Available Las ciudades bajo desarrollo capitalista experimentaron a lo largo de las últimas décadas profundos procesos de fragmentación urbana. Aquellas con función turística agudizaron este panorama dado el aumento del valor del suelo urbano. Tal es el caso de San Carlos de Bariloche, en la Patagonia andina argentina. Su alta compartimentación, sumada a la gran dispersión espacial de su ejido municipal y topografía accidentada, limitaron la funcionalidad y cohesión interna. Se propone avanzar en la comprensión de dichas fracturas urbanas a partir del estudio de las asociaciones vecinales. Se trabaja desde la escala del barrio entendido como condensador de problemáticas globales, nacionales y locales y a partir de la figura de la Junta Vecinal en tanto unidad primaria de participación y principal articuladora en las relaciones entre vecinos, barrios y gobierno local. La hipótesis propone que la gestión, las relaciones y funciones asumidas desde las Juntas Vecinales, íntimamente vinculadas a la condición de clase de sus vecinos, permiten una mejor interacción a escala intraurbana y promueven situaciones más inclusivas en los sectores populares. Se da cuenta también del rol de las Juntas Vecinales en la construcción de imaginarios urbanos que inciden en un acercamiento-alejamiento de las distancias sociales intraurbanas.

  14. Vulnerability to climate warming of Liolaemus pictus (Squamata, Liolaemidae), a lizard from the cold temperate climate in Patagonia, Argentina.

    Science.gov (United States)

    Kubisch, Erika Leticia; Fernández, Jimena Beatriz; Ibargüengoytía, Nora Ruth

    2016-02-01

    The vulnerability of populations and species to global warming depends not only on the environmental temperatures, but also on the behavioral and physiological abilities to respond to these changes. In this sense, the knowledge of an organism's sensitivity to temperature variation is essential to predict potential responses to climate warming. In particular, it is interesting to know how close species are to their thermal limits in nature and whether physiological plasticity is a potential short-term response to warming climates. We exposed Liolaemus pictus lizards, from northern Patagonia, to either 21 or 31 °C for 30 days to compare the effects of these treatments on thermal sensitivity in 1 and 0.2 m runs, preferred body temperature (T pref), panting threshold (T pant), and critical minimum temperature (CTMin). Furthermore, we measured the availability of thermal microenvironments (operative temperatures; T e) to measure how close L. pictus is, in nature, to its optimal locomotor performance (T o) and thermal limits. L. pictus showed limited physiological plasticity, since the acclimation temperature (21 and 31 °C) did not affect the locomotor performance nor did it affect T pref, the T pant, or the CTMin. The mean T e was close to T o and was 17 °C lower than the CTMax. The results suggest that L. pictus, in a climate change scenario, could be vulnerable to the predicted temperature increment, as this species currently lives in an environment with temperatures close to their highest locomotor temperature threshold, and because they showed limited acclimation capacity to adjust to new thermal conditions by physiological plasticity. Nevertheless, L. pictus can run at 80 % or faster of its maximum speed across a wide range of temperatures near T o, an ability which would attenuate the impact of global warming.

  15. Meltwater palaeohydrology of the Baker River basin (Chile/Argentina) during Late Pleistocene deglaciation of the Northern Patagonia Icefield

    Science.gov (United States)

    Thorndycraft, Varyl; Bendle, Jacob; Benito, Gerardo; Sancho, Carlos; Palmer, Adrian; Rodríguez, Xavier

    2016-04-01

    The Late Pleistocene deglaciation of the Northern Patagonia Icefield (NPI) was characterised by rapid ice sheet thinning and retreat, and the development of large proglacial lake systems characterised by continental scale drainage reversals. In this region, research has focused primarily on the identification of former ice-limits (e.g. moraine ridges) for geochronological analyses, with little attention given to the meltwater palaeohydrology of major river valleys. The Baker River catchment drains the majority of the eastern ice shed of the NPI, with a basin area of 29,000 km2 that includes the large transboundary lakes of General Carrera/Buenos Aires and Cochrane/Puerreydón. The Baker River valley is aligned north to south, crossing the east-west valleys of the main NPI outflow glaciers, and thus represents an important aspect of regional Late Pleistocene palaeogeography. The Baker River valley therefore has the potential to refine regional models of deglaciation through better understanding of relationships between glacier dynamics, ice dammed lakes and meltwater pathways. Here we present geomorphological mapping from the Atlantic-Pacific drainage divide (over 150 km east of the Cordillera) to the lower Baker valley, in order to reconstruct Late Pleistocene palaeohydrology. We provide new mapping of palaeolake shoreline elevations and evidence for glacial lake outburst flood (GLOF) pathways that require a re-evaluation of the currently accepted palaeogeographic models. For example, the palaeohydrological evidence does not support existing models of a unified Buenos Aires/Puerreydón mega-lake at ca. 400m elevation. We propose a relative chronology of palaeohydrological events that help refine the published moraine chronology derived from cosmogenic nuclide exposure dating. Controls on Late Pleistocene meltwater palaeohydrology of the Baker catchment are discussed, including the interplay of glacial processes and regional tectonics, in particular, dynamic

  16. Evaluation of neophobia and its potential impact upon predator control techniques: a study on two sympatric foxes in southern Patagonia.

    Science.gov (United States)

    Travaini, Alejandro; Vassallo, Aldo Iván; García, Germán Oscar; Echeverría, Alejandra Isabel; Zapata, Sonia Cristina; Nielsen, Sigrid

    2013-01-01

    An alternative approach to increase the efficiency of predator control and selectivity is to consider the natural behavioural repertoire of the target species and how such behaviours may increase their vulnerability. Neophobia, or the hesitancy to approach a novel food item, object, or place, is an important factor influencing the investigative behaviour of animals, and its incorporation to predator control techniques may help to reduce losses of livestock to predators. In this study, we simultaneously evaluated the existence and intensity of neophobic responses in two sympatric fox species, the Culpeo (Pseudalopex culpaeus) and the Grey (P. griseus) foxes in southern Patagonia, Argentina. For this purpose, we used bait stations to compare fox behavioural responses in the absence (pre-treatment), presence (treatment) and removal (post-treatment) of a novel stimulus, which consisted of an orange PVC-traffic cone. Both fox species showed a neophobic response: bait-station visitation rates decreased (P=0.005 and P=0.048, for Culpeo and Grey foxes, respectively) in the presence of the novel object. The intensity of the response differed between species being higher for Culpeo foxes (approximately 80% of reduction in visitation rate during treatment for Culpeo foxes vs. 10% for Grey foxes). However, the bait-station visitation pattern after novel object removal indicated that animals probably increased exploration of the station. The high level of neophobia achieved by the Culpeo fox, together with an increase in post-treatment site exploration, suggests that behavioural manipulations (reduction of neophobia and its consequent increase in risk taking) could improve selective and efficient fox control in rural areas where livestock production is a major economic activity.

  17. Origin and evolution of the Laguna Potrok Aike maar (Southern Patagonia, Argentina) as revealed by seismic data

    Science.gov (United States)

    Gebhardt, C.; de Batist, M. A.; Niessen, F.; Anselmetti, F.; Ariztegui, D.; Haberzettl, T.; Ohlendorf, C.; Zolitschka, B.

    2009-12-01

    Seismic reflection and refraction data provide insights into the sedimentary infill and the underlying volcanic structure of Laguna Potrok Aike, a maar lake situated in the Pali Aike Volcanic Field, Southern Patagonia. The lake has a diameter of ~3.5 km, a maximum water depth of ~100 m and a presumed age of ~770 ka. Its sedimentary regime is influenced by climatic and hydrologic conditions related to the Antarctic Circumpolar Current, the Southern Hemispheric Westerlies and sporadic outbreaks of Antarctic polar air masses. Multiproxy environmental reconstructions of the last 16 ka document that this terminal lake is highly sensitive to climate change. Laguna Potrok Aike has recently become a major focus of the International Continental Scientific Drilling Program and was drilled down to 100 m below lake floor in late 2008 within the PASADO project. The sediments are likely to contain a continental record spanning the last ca. 80 kyrs unique in the South American realm. Seismic reflection data show relatively undisturbed, stratified lacustrine sediments at least in the upper ~100 m of the sedimentary infill but are obscured possibly by gas and/or coarser material in larger areas. A model calculated from seismic refraction data reveals a funnel-shaped structure embedded in the sandstone rocks of the surrounding Santa Cruz Formation. This funnel structure is filled by lacustrine sediments of up to 370 m in thickness. These can be separated into two distinct subunits with low acoustic velocities of 1500-1800 m s-1 in the upper subunit pointing at unconsolidated lacustrine muds, and enhanced velocities of 2000-2350 m s-1 in the lower subunit. Below these lacustrine sediments, a unit of probably volcanoclastic origin is observed (>2400 m s-1). This sedimentary succession is well comparable to other well-studied sequences (e.g. Messel and Baruth maars, Germany), confirming phreatomagmatic maar explosions as the origin of Laguna Potrok Aike.

  18. Primer registro paleoparasitológico de Trichuris SP (nematoda, capilariidae en muestras asociadas a restos humanos del Holoceno tardío de Patagonia septentrional

    Directory of Open Access Journals (Sweden)

    Fugassa, Martín H.

    2009-01-01

    Full Text Available En el marco de los estudios paleoepidemiológicos que se realizan en restos arqueológicos asignados a poblaciones de cazadores-recolectores de Patagonia, este trabajo presenta información novedosa acerca de la presencia de parásitos en muestras de sedimento de las cavidades pélvicas correspondientes a individuos que habitaron la costa norte de Patagonia durante el Holoceno Tardío. Fueron analizados 3 casos de diferente cronología y en dos de ellos, los de menor antigüedad relativa, los resultados fueron positivos para la presencia de Trichuris trichiura. Es interesante mencionar al respecto que para el período que involucra a los dos casos positivos, la información arqueológica registra un proceso de intensificación en el que se explota una mayor diversidad de fauna y se incrementan los artefactos de molienda en los sitios. Entre las posibles causas propuestas para este proceso se encuentran el aumento demográfico y/o el nucleamiento poblacional en espacios favorables que comienzan a saturarse, hecho consistente con la evidencia cultural obtenida al momento y con la presencia de Trichuris sp.

  19. Reptile and rodent parasites in raptor pellets in an archaeological context: the case of Epullán Chica (northwestern Patagonia, Argentina)

    Science.gov (United States)

    Beltrame, María Ornela; Fernández, Fernando Julián; Sardella, Norma Haydeé

    2015-07-01

    Paleoparasitology is the study of parasite remains from archaeological and paleontological sites. Raptor pellets can be used as source for paleoparasitological information in archaeological sites. However, this zooarchaeological material has been scarcely studied. Epullán Chica (ECh) is an archaeological site in northwestern Patagonia. This cave yielded remains from more than 2000 years before present. The aim of this paper was to study the parasite remains found in owl pellets from the archaeological site ECh, and to discuss the paleoparasitological findings in an archaeological context. Twenty two raptor pellets were examined for parasites. The pellets were whole processed by rehydration in a 0.5% water solution of trisodium phosphate, followed by homogenization, filtered and processed by spontaneous sedimentation. Eight out of 22 bird pellets examined were positive for parasites from reptiles and rodents. Representatives of 12 parasite taxa were recorded; nine of this parasitic species were reported for the first time from ancient samples from Patagonia. This is the first time that pellets give evidences of ancient reptile parasites from archaeological contexts. It is noteworthy that Late Holocene hunter-gatherers of the upper Limay River basin, could have been exposed to some of these zoonotic parasites. Future paleoparasitological studies on owl pellets may reflect even more the parasitological diversity of all micromammal and reptile species presents in ancient times.

  20. Respuesta del microfitoplancton a la adición de nitrato y ácido silícico en fiordos de la Patagonia chilena

    Directory of Open Access Journals (Sweden)

    Pamela Labbé-Ibáñez

    2015-03-01

    Full Text Available La Patagonia chilena está experimentando un aumento del uso del suelo y océano costero y el acelerado derretimiento de algunos glaciares, por lo que uno de los escenarios a futuro es que los fiordos adyacentes reciban cantidades variables de agua dulce y nutrientes inorgánicos. Se estudió la respuesta de ensambles de fitoplancton de los fiordos Reloncaví en invierno y Comau en primavera, a la adición de nitrato y ácido silícico en experimentos de microcosmos. Los ensambles fitoplanctónicos estudiados respondieron a la adición de nutrientes con incrementos en la abundancia celular biomasa autotrófica (clorofila-a y cambios en la composición específica, destacando el cambio de dominancia de especies de diatomeas pennadas a céntricas formadoras de cadenas. Estos resultados dan indicios acerca de los factores que afectan a las comunidades microalgales en un escenario de cambio climático e intervención antrópica de los fiordos de la Patagonia Norte.

  1. Isotopic studies on detrital zircons of Silurian-Devonian siliciclastic sequences from Argentinean North Patagonia and Sierra de la Ventana regions: comparative provenance

    Science.gov (United States)

    Uriz, Norberto J.; Cingolani, Carlos A.; Chemale, Farid; Macambira, Moacir B.; Armstrong, Richard

    2011-04-01

    The Silurian-Devonian siliciclastic sedimentary units known as Sierra Grande Formation and the upper part of the Ventana Group crop out in the eastern area of the North Patagonian Massif and in the Ventania system, toward the Atlantic border of Argentina. Both sequences show similar stratigraphical characteristics and were deposited in a shallow marine platform paleoenvironment. Previous contributions have provided evidence of an allochthonous Patagonia terrane that amalgamate to Gondwana during the Permian-Triassic. However, other lines of research support a crustal continuity southward, where the Pampean and Famatinian events extend into the northern Patagonia. In either case, the detrital input to the Eo-Mesopaleozoic basins generated along the passive margin tectonic setting should reflect the sedimentary sources. In this contribution, new age data on the sedimentary provenance of these units is provided by U-Pb and Lu-Hf isotopic studies on detrital zircons, using LA-ICP-MS and SHRIMP methodologies. The main sedimentary sources of detrital zircons for both regions are of Cambrian-Ordovician and Neoproterozoic age, while a secondary mode is Mesoproterozoic. Zircons from older cratonic sources (Mesoarchean-Paleoproterozoic ages) are scarcely recorded. The sample from the upper section of the Devonian Lolén Formation (Ventana Group) shows an important change in the sedimentary provenance, with a main mode of Mesoproterozoic detrital zircons. Detrital source areas considering the orogenic cycles known for southwest South America (Famatinian, Pampean-Brasiliano, Mesoproterozoic-`Grenvillian' and Paleoproterozoic-`Transamazonian') are proposed.

  2. Central Solenoid

    CERN Multimedia

    2002-01-01

    The Central Solenoid (CS) is a single layer coil wound internally in a supporting cylinder housed in the cryostat of the Liquid Argon Calorimeter. It was successfully tested at Toshiba in December 2000 and was delivered to CERN in September 2001 ready for integration in the LAr Calorimeter in 2003. An intermediate test of the chimney and proximity cryogenics was successfully performed in June 2002.

  3. Europa central

    Directory of Open Access Journals (Sweden)

    Karel BARTOSEK

    2010-02-01

    Full Text Available La investigación francesa continúa interesándose por Europa Central. Desde luego, hay límites a este interés en el ambiente general de mi nueva patria: en la ignorancia, producto del largo desinterés de Francia por este espacio después de la Segunda Guerra Mundial, y en el comportamiento y la reflexión de la clase política y de los medios de comunicación (una anécdota para ilustrar este ambiente: durante la preparación de nuestro coloquio «Refugiados e inmigrantes de Europa Central en el movimiento antifascista y la Resistencia en Francia, 1933-1945», celebrado en París en octubre de 1986, el problema de la definición fue planteado concreta y «prácticamente». ¡Y hubo entonces un historiador eminente, para quién Alemania no formaría parte de Europa Central!.

  4. Mycorrhizal compatibility and symbiotic reproduction of Gavilea australis, an endangered terrestrial orchid from south Patagonia.

    Science.gov (United States)

    Fracchia, Sebastián; Aranda-Rickert, Adriana; Flachsland, Eduardo; Terada, Graciela; Sede, Silvana

    2014-11-01

    Gavilea australis is a terrestrial orchid endemic from insular south Argentina and Chile. Meeting aspects of mycorrhizal fungi identity and compatibility in this orchid species is essential for propagation and conservation purposes. These knowledge represent also a first approach to elucidate the mycorrhizal specificity of this species. In order to evaluate both the mycorrhizal compatibility and the symbiotic seed germination of G. australis, we isolated and identified its root endophytic fungal strains as well as those from two sympatric species: Gavilea lutea and Codonorchis lessonii. In addition, we tested two other strains isolated from allopatric terrestrial orchid species from central Argentina. All fungal strains formed coilings and pelotons inside protocorms and promoted, at varying degrees, seed germination, and protocorm development until seedlings had two to three leaves. These results suggest a low mycorrhizal specificity of G. australis and contribute to a better knowledge of the biology of this orchid as well as of other sympatric Patagonian orchid species, all of them currently under serious risk of extinction.

  5. Central pain.

    Science.gov (United States)

    Singh, Supreet

    2014-12-01

    Questions from patients about pain conditions and analgesic pharmacotherapy and responses from authors are presented to help educate patients and make them more effective self-advocates. The topic addressed in this issue is central pain, a neuropathic pain syndrome caused by a lesion in the brain or spinal cord that sensitizes one's perception of pain. It is a debilitating condition caused by various diseases such as multiple sclerosis, strokes, spinal cord injuries, or brain tumors. Varied symptoms and the use of pharmacological medicines and nonpharmacological therapies will be addressed.

  6. central t

    Directory of Open Access Journals (Sweden)

    Manuel R. Piña Monarrez

    2007-01-01

    Full Text Available Dado que la Regresión Ridge (RR, es una estimación sesgada que parte de la solución de la regresión de Mínimos Cuadrados (MC, es vital establecer las condiciones para las que la distribución central t de Student que se utiliza en la prueba de hipótesis en MC, sea también aplicable a la regresión RR. La prueba de este importante resultado se presenta en este artículo.

  7. Analysis of the Aeromagnetic Anomalies of the Auca Mahuida Volcano, Patagonia, Argentina

    Science.gov (United States)

    Longo, L. M.; De Ritis, R.; Ventura, G.; Chiappini, M.

    2016-10-01

    We present the analysis of the subsurface structure of the Auca Mahuida volcano based on high-resolution aeromagnetic data integrated with the available geological information. Most of the detected magnetic anomalies have a dipolar structure opposite to that of the present geomagnetic field. According to the available geochronological data and paleomagnetic measurements, the source bodies of Auca Mahuida mainly emplaced in the Matuyama reverse polarity chron. The Reduction-to-the-Pole map confirms that the magnetization direction is mainly reverse with only few anomalies normally magnetized. Two opposite, coexisting polarities do not allow to fully remove the dipolar character of the field in the Reduction-to-the-Pole transformation. Therefore, we model the measured anomaly field by applying analytical techniques that are independent of the magnetization direction. The obtained anomaly strikes and source geometries indicate an emplacement of intrusive bodies controlled by the regional faults affecting the Auca Mahuida basement and the sedimentary successions of the Neuquén basin. Magma upraised along these faults and fractures feeding the volcanic activity and subsequently crystallized. The averaged power spectrum and Euler Deconvolution indicate source depths consistent with those of the intrusions recognized in wells. Borehole data highlight the widespread presence of intrusive bodies below the Auca Mahuida central crater and the peripheral sectors at depth of 2 km below sea level. These bodies have played a major role in the thermal maturation of hydrocarbons and in the subsequent accumulation of oil below the volcano. The obtained results shed light on the Auca Mahuida feeding system and on the intrusions geometry, also pointing out the effectiveness of the magnetic prospecting in the oil industry even in presence of strong remanent magnetization.

  8. ON THE UNDERSTANDING OF AEOLIAN SEQUENCE STRATIGRAPHY: AN EXAMPLE FROM MIOCENE-PLIOCENE DEPOSITS IN PATAGONIA, ARGENTINA

    Directory of Open Access Journals (Sweden)

    CARLOS ZAVALA

    2001-07-01

    Full Text Available Upper Tertiary aeolian strata (Río Negro Formation outcrop in extensive sea cliffs at the Northeast of Patagonia. These outcrops show deposits corresponding to a complete suite of aeolian and aeolian related sub-environments, and also provide excellent exposures to analyse the sedimentology and internal architecture from a sequence stratigraphic point of view. Field studies, supplemented withline-drawings of oblique photographs, allowed the recognition of seven aeolian depositional sequences within the succession, each one bounded by regional super surfaces (or deflation surfaces. Internally these aeolian sequences display a cyclic recurrence in facies, that yields a tentative genetic model for their evolution. As documented from field examples, each basic aeolian depositional sequence was deposited during a single aggradational period, and is bounded by unconformities related to degradational periods. Degradational periods are regional deflationary events, that resulted in deep-scoured to flat surfaces, characterised by erosion / non deposition in which the only recognised accumulation is isolated and large angular blocks of fine-grained aggregates, interpreted as residual remnants of deposits of the previous sequence. Aggradational periods are characterised by a near- continuous accumulations responsible for the sequence building. Differences in the aeolian sediment budget to the area and the rising rate of water table control the related facies types, and allow to discriminateearly and late aggradational sub-periods. Early aggradational sub-periods form under conditions of relatively fast rising water tables associated with moderate aeolian sediment budget, thus resulting in the development of extended wet interduneslaterally associated with aeolian dunes and dry interdunes. During late aggradational sub-periods, the depositional surface outdistanced the water table, and aeolian dunes and dry interdunes tend to predominate. This sub

  9. Influence of precipitation, landscape and hydrogeomorphic lake features on pelagic allochthonous indicators in two connected ultraoligotrophic lakes of North Patagonia

    Energy Technology Data Exchange (ETDEWEB)

    Queimalinos, Claudia, E-mail: queimalinosc@comahue-conicet.gob.ar [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Reissig, Mariana; Dieguez, Maria del Carmen [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Arcagni, Marina; Ribeiro Guevara, Sergio [Laboratorio de Analisis por Activacion Neutronica (LAAN), Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Av. Bustillo 9500, R8402AGP Bariloche, Rio Negro (Argentina); Campbell, Linda [School of Environmental Studies, Saint Mary' s University, 923 Robie Street, Halifax, Nova Scotia, Canada B3H-3C3 (Canada); Soto Cardenas, Carolina [Laboratorio de Fotobiologia, Instituto de Investigaciones en Biodiversidad y Medio Ambiente (INIBIOMA, UNComahue-CONICET), Quintral 1250, R8400FRF Bariloche, Rio Negro (Argentina); Rapacioli, Raul [Facultad de Ingenieria, Universidad Nacional del Comahue, Buenos Aires1400, Q8300IBX Neuquen (Argentina); and others

    2012-06-15

    We investigated the terrestrial influence on two chained deep ultraoligotrophic lakes of North Patagonia (Argentina) through the seasonal analysis of two pelagic allochthonous indicators: i) water color, as a proxy of allochthonous dissolved organic matter in lakes; and ii) the color to chlorophyll a ratio (Color:Chla), as an indicator of the relationship between allochthonous and autochthonous carbon pools. We also evaluated the potential transfer pathways of the allochthonous dissolved organic matter into the pelagic food webs of these deep lakes, including the natural zooplankton {delta}{sup 13}C in the analysis. The dynamics of the allochthonous indicators were related to the precipitation regime, water level fluctuations, and hydrogeomorphic and catchment features of lakes Moreno East and Moreno West. The water color (absorbance at 440 nm) was extremely low (< 0.28 m{sup -1}) in both lakes regardless of the season. However, precipitation and snowmelt regimes drove the increase and decrease of water color, respectively. A significant positive relationship between the zooplankton bulk {delta}{sup 13}C with the water color would suggest an input of allochthonous organic carbon into the pelagic consumers. The incorporation of the dissolved allochthonous material into higher trophic levels is likely favored by the bacterivorous behavior of planktonic organisms, mixotrophic flagellates and ciliates, which dominate the pelagic food webs of these Patagonian lakes. Morphometric aspects, mainly the higher water residence time, led to lower values of allochthony in Moreno East compared to Moreno West, probably accentuated by its upper position in the lake chain. Overall, our results suggest that these allochthonous signals can bring insight into the magnitude of the interaction between terrestrial environments and lake ecosystems, even in extremely clear and ultraoligotrophic systems, such as the Andean Patagonian lakes. - Highlights: Black-Right-Pointing-Pointer Pelagic

  10. Hydrogen as a vector in Mercosul for the transmission of wind power from Patagonia and as a vehicle to its overseas exportation; Hidrogeno como vector en el Mercosur para transmision de energia eolica desde la Patagonia y como vehiculo para su exportacion a ultramar

    Energy Technology Data Exchange (ETDEWEB)

    Spinadel, Erico; Gracia Nunes, Sabas Luis; Gamallo, Florencio [Buenos Aires Univ. (Argentina). Facultad de Ingenieria. GENCo - Grupo de I y D en Energias No Convencionales

    1997-12-31

    The wind resource in Patagonia is one of the most important energetic reserves in Latin America, and should be taken into account in any high-scale generation project proposed for this area. However, the direct connection of wind farms to the net introduces some unstability problems that limit the amount of admissible wind power in it. The authors`s proposal is applying all the obtained wind energy to an electrolytic process for hydrogen production, for using it later as an alternative fuel in conventional power stations. (author) 8 refs.; e-mail: postmaster at genco.uba.ar

  11. Comparación de condiciones de cultivo para el aislamiento y recuento simultáneo de levaduras de suelos de bosques nativos de Nothofagus spp. (Fagaceae) de la Patagonia Argentina Comparison of culture conditions for isolation and count of soil yeasts from Nothofagus spp. (Fagaceae) native forest of Argentinean Patagonia

    OpenAIRE

    2009-01-01

    Se compararon las condiciones de cultivo para aislar y contar levaduras del suelo de los bosques nativos de Nothofagus spp. en la Patagonia de Argentina. En este trabajo se propone la utilización de medios de cultivo adicionados con Rosa de Bengala 25 >g/mL y 200 >g/mL de Cloranfenicol. En estas condiciones se obtuvieron recuentos de levaduras que rondan 10³ UFC/g de suelo (aproximadamente 4% de la flora microbiana detectada). Se compararon los resultados de aislamientos por el método enrique...

  12. Identification of Calderas Associated With The Acidic Jurassic Volcanism of Southern Patagonia, Argentina

    Science.gov (United States)

    Chernicoff, C. J.; Salani, F. M.

    During the Jurassic, the Patagonian region was subject to a predominantly acidic volcanism locally known as the Chon Aike Volcanic Province, related to the breakup of Gondwana. It comprises ignimbrites, breccias and agglomerates, and a minor component of rhyolitic and dacitic lava domes. In the study area (Río Seco region, Santa Cruz Province), the Jurassic volcanics are largely overlain by Neogene and Quaternary sediments. However, the aeromagnetic survey of this region has unravelled the magnetic pattern of the volcanics, notably two conspicuous calderas, since the young cover sediments are non-magnetic. The magnetic susceptibility of the volcanic rocks ranges 50 to 80 x 10-5 S.I., as oppossed to the nearly null values of the overlying sediments. The geological interpretation of the aeromagnetic survey is mostly based on the analytic signal of the total magnetic intensity, where two distinct sub-circular magnetic lineaments have been recognized and regarded as calderic structures. The eastern caldera, 30 km wide, is centered at 48º 52' S.L./ 68º 02' W.L., and the western caldera, 23 km wide, is centered at 48º 53' S.L. / 68º 29' W.L.. In addition, a number of smaller, high gradient magnetic anomalies have been identified and interpreted as intra- and extracaldera domes. In the eastern caldera, a number of domes follow an anular pattern of fractures regarded as the boundary of an older, outer caldera. A magnetic circular lineament located within the latter structure has been interpreted as a younger, inner caldera which presents a number of small domes in its central depression; additional domes are also located in between the two calderic structures. The western caldera is less complex since it comprises a single structure with intra-caldera domes. The total magnetic gradient (analytic signal) associated with the domes is one order of magnitude higher (0.1 to 0.2) than the mean value of the region (0.03). In addition to the anular fractures and domes, a

  13. Distribución temporal y espacial de señales de violencia interpersonal en muestras de cráneos del norte de Patagonia

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    Barrientos, Gustavo

    2003-01-01

    Full Text Available Recientemente se ha planteado que, como consecuencia de las modificaciones ambientales (i.e. aumentos en la temperatura y sequías prolongadas acontecidas durante la denominada Anomalía Climática Medieval (ca. 1150 y 600 años calendáricos AP, se habrían creado las condiciones para un aumento regional y local en la densidad demográfica y un aumento de la circunscripción espacial de los grupos cazadores-recolectores, principalmente en sectores con disponibilidad de agua superficial (v.g. valles fluviales y con mayor productividad (v.g. litoral marítimo. Nucleamientos poblacionales de este tipo tienden a promover, en sociedades de pequeña escala, un aumento en los niveles de conflicto y violencia interpersonal dentro y entre los grupos. Con el fin de evaluar esta hipótesis, se analizó una muestra integrada por un mínimo de 540 cráneos procedentes de las cuencas inferiores de los ríos Chubut y Negro, pertenecientes a las colecciones del Museo de Ciencias Naturales de La Plata. En este trabajo se presentarán y se discutirán los datos referidos a la distribución temporal y espacial de los casos con identificación positiva de lesiones atribuibles a violencia interpersonal, prestándose particular atención a la descripción de los tipos de lesiones registradas.

  14. First fossil record of Discocephalinae (Insecta, Pentatomidae): a new genus from the middle Eocene of Río Pichileufú, Patagonia, Argentina

    Science.gov (United States)

    Petrulevičius, Julián F.; Popov, Yuri A.

    2014-01-01

    Abstract A new genus and species of Discocephalini, Acanthocephalonotum martinsnetoi gen. n. et sp. n. is described from Río Pichileufú, middle Eocene of Patagonia, Argentina at palaeolatitude ~ 46°S. The new species is the first fossil representative of the Discocephalinae. This taxon is extant in equatorial to subtropical America, and some species reach warm temperate latitudes (Buenos Aires province). The new genus is distinguished from the other genera of Discocephalini by the combination of these characters: interocular width greater than head length; head massive and quadrangular with the anterior margin almost straight; juga touching each other; labrum thick and curved; triangular ante-ocular process extending beyond the eye; broad spine-like antero-lateral process of the pronotum; pronotum explanate and bean shaped; scutellum triangular with a circular tongue reaching the anterior side of abdominal segment 7; and wings well developed with membrane just surpassing end of abdomen. PMID:25061387

  15. El cambio climático global en la Patagonia desde el viaje de Charles Darwin hasta nuestros días

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    Jorge Rabassa

    2010-08-01

    Full Text Available El viaje del Beagle que trajo a Charles Darwin a América del Sur entre 1832 y 1835 AD y en particular, al territorio argentino, se desarrolló bajo condiciones climáticas muy desfavorables: frías, secas y ventosas, correspondientes a las condiciones predominantes en la última fase de la pequeña edad del hielo, un episodio frío global que caracterizó a los siglos XVII, XVIII y XIX. Esta fase es conocida como mínimo de Dalton, en referencia a la disminución relativa de la frecuencia de las manchas solares, lo cual redunda en una disminución de la radiación solar y como consecuencia, en menores temperaturas medias globales en ese período. Darwin fue perfectamente consciente de dichas condiciones climáticas, que se manifestaban fuertemente en Europa, en particular en los Alpes, y así lo transmite en sus escritos. Desde el viaje de Darwin a la Patagonia, las condiciones climáticas y ambientales cambiaron sustancialmente, especialmente luego de 1850 AD y, finalmente, después de mediados de la década de 1970 AD. Algunas de las más importantes consecuencias del cambio climático global son el aumento de la temperatura media anual o la temperatura estacional, la elevación o disminución de las precipitaciones al nivel regional, el continuo ascenso global del nivel del mar y un incremento significativo de la frecuencia de eventos meteorológicos extremos. El impacto de esos cambios ha sido observado en los glaciares de Patagonia y Tierra del Fuego, por lo menos desde 1978 AD, y particularmente en la última década del siglo XX. Los impactos más notables son la rápida recesión de las márgenes del hielo en los glaciares, el adelgazamiento de la cobertura glacial, la elevación de la línea de nieve regional y la reducción de las áreas andinas bajo condiciones de suelos permanentemente congelados (permafrost, como han demostrado estudios científicos recientes. A la tasa presente de recesión del hielo glacial, la mayoría, si no

  16. El agente penitenciario. Metodología de la investigación social en un estudio de caso en la Patagonia Norte, Argentina(2012-2014

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    Beatriz Kalinsky

    2015-12-01

    Full Text Available Damos a conocer un recorrido metodológico en el estudio de los agentes penitenciarios que cumplen funciones en cárceles ubicadas en la Patagonia Norte de la Argentina (2012-2014. El objetivo de este escrito es contribuir al análisis de cuestiones metodológicas vinculadas con el estudio de la agencia penitenciaria, en especial el de los agentes que se ubican en el escalafón más bajo de esta estructura jerarquizada y verticalista, porque están en continuo contacto con la población detenida y sufren tanto el peso imperativo de la institución como los reclamos, mal comportamiento y estados variables de ánimo de quienes están privados legítimamente de su libertad, al cumplir una actividad imprescindible y al mismo tiempo invisible.

  17. Allochthonous subsidies of organic matter across a lake-river-fjord landscape in the Chilean Patagonia: Implications for marine zooplankton in inner fjord areas

    Science.gov (United States)

    Vargas, Cristian A.; Martinez, Rodrigo A.; San Martin, Valeska; Aguayo, Mauricio; Silva, Nelson; Torres, Rodrigo

    2011-03-01

    Ecosystems can act as both sources and sinks of allochthonous nutrients and organic matter. In this sense, fjord ecosystems are a typical interface and buffer zone between freshwater systems, glaciated continents, and the coastal ocean. In order to evaluate the potential sources and composition of organic matter across fjord ecosystems, we characterized particulate organic matter along a lake-river-fjord corridor in the Chilean Patagonia using stable isotope (δ 13C) and lipid (fatty acid composition) biomarker analyses. Furthermore, estimates of zooplankton carbon ingestion rates and measurements of δ 13C and δ 15N in zooplankton (copepods) were used to evaluate the implications of allochthonous subsidies for copepods inhabiting inner fjord areas. Our results showed that riverine freshwater flows contributed an important amount of dissolved silicon but, scarce nitrate and phosphate to the brackish surface layer of the fjord ecosystem. Isotopic signatures of particulate organic matter from lakes and rivers were distinct from their counterparts in oceanic influenced stations. Terrestrial allochthonous sources could support around 68-86% of the particulate organic carbon in the river plume and glacier melting areas, whereas fatty acid concentrations were maximal in the surface waters of the Pascua and Baker river plumes. Estimates of carbon ingestion rates and δ 13C in copepods from the river plume areas indicated that terrestrial carbon could account for a significant percentage of the copepod body carbon (20-50%) during periods of food limitation. Particulate organic matter from the Pascua River showed a greater allochthonous contribution of terrigenous/vascular plant sources. Rivers may provide fjord ecosystems with allochthonous contributions from different sources because of the distinct vegetation coverage and land use along each river's watershed. These observations have significant implications for the management of local riverine areas in the context of

  18. ESTIMACIÓN DE EROSIÓN HIDRICA DE SUELOS PARA PLAN DE MANEJO DEL CAMPO FORESTAL AGUAS FRÍAS, PATAGONIA ARGENTINA

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    Ana C. Dufilho

    2011-12-01

    Full Text Available In Argentine Patagonia there exist large extensions of lands degraded by overgrazing, this favours soil water erosion. Two million hectares are eligible for forestation (Gallo et al. 2005, with some environmental limitations that require previous studies to prepare development and sustainability proposals. The study area is located in the right margin of the Litrán River, 25 kms of its estuary in Aluminé Lake (Province of Neuquén. In this area, some Mapuche (araucanian communities carry out stock breeding (mainly goats using a migrating system. This region presents very severe Aeolian and hydrological erosion. The objective of the afforestation management plan of this land, is the design of control measures, to stop erosion, like perimeter close, afforestation and structural measures for controlling erosional gully. It is then necessary, to characterize the actual and potential erosion, that would allow to carry out with measures monitoring to implement controls and mitigation. Paper presents, pedology map by interpreting and georreferencing satellite images by a Geographical Information System. (GIS. The mapping methodology was based in Hierarchical Classification of Landforms, which is the structure of the geopedology focus for mapping soil (Zinck, 1989. The classification of actual erosion was obtained from the method of the Bureau of Land Management (USDI by visual inspection of seven aspects of erosion in surface. The estimation of the potential erosion of the floors of the forest field was carried out utilizing the Universal Soil Lost Equation (USLE and ArcGis 9,2 (ESRI, 2006 to carry out the spatial analysis, obtaining a map of annual soil loss ( tn/has/year with a spatial resolution of 30 m. The application of spatial analysis tools in the study of soil water erosion in Patagonia, Argentina contributes to the objective of defining define a program of development and adequate management, as a function of the state and degree of

  19. Geochemistry of surface sediments from the fjords of Northern Chilean Patagonia (44-47°S): Spatial variability and implications for paleoclimate reconstructions

    Science.gov (United States)

    Bertrand, Sébastien; Hughen, Konrad A.; Sepúlveda, Julio; Pantoja, Silvio

    2012-01-01

    The Patagonian fjords have a clear potential to provide high-resolution sedimentary and geochemical records of past climate and environmental change in the Southern Andes. To improve our ability to interpret these proxy records, we investigated the processes that control fjord sediment inorganic geochemistry through a geochemical, mineralogical and sedimentological analysis of surface sediment samples from the fjords of Northern Chilean Patagonia. A simple Terrestrial Index based on measurements of salinity and Fraction of Terrestrial Carbon was used to estimate the terrestrial input/river discharge at each site. Our results demonstrate that, under the cold climate conditions of Patagonia, chemical weathering is weak and the inorganic geochemical composition of the fjord sediments is primarily controlled by hydrodynamic mineralogical sorting, i.e., the intensity of river discharge. Our results suggest that the distribution of Fe, Ti and Zr in surface sediments is controlled by their association with heavy and/or coarse minerals, whereas Al is independent of hydrodynamic processes. The elemental ratios Fe/Al, Ti/Al and Zr/Al are therefore well suited for estimating changes in the energy of terrestrial sediment supply into the fjords through time. Zr/Al is particularly sensitive in proximal environments, while Fe/Al is most useful in the outer fjords and on the continental margin. In the most proximal environments, however, Fe/Al is inversely related to hydrodynamic conditions. Caution should therefore be exercised when interpreting Fe/Al ratios in terms of past river discharge. The application of these proxies to long sediment cores from Quitralco fjord and Golfo Elefantes validates our interpretations. Our results also emphasize the need to measure Al-based elemental ratios at high precision, which can be achieved using simultaneous acquisition ICP-AES technology. This study therefore constitutes a strong basis for the interpretation of sedimentary records from the

  20. Reconstruction of a glacial lake outburst flood (GLOF) in the Engaño Valley, Chilean Patagonia: Lessons for GLOF risk management.

    Science.gov (United States)

    Anacona, Pablo Iribarren; Mackintosh, Andrew; Norton, Kevin

    2015-09-15

    Floods from moraine-dammed lake failures can have long standing effects not only on riverine landscapes but also on mountain communities due to the high intensity (i.e. great depth and high velocities) and damaging capacity of glacial lake outburst floods (GLOFs). GLOFs may increase in frequency as glaciers retreat and new lakes develop and there is an urgent need to better understand GLOF dynamics and the measures required to reduce their negative outcomes. In Patagonia at least 16 moraine-dammed lakes have failed in historic time, however, data about GLOF dynamics and impacts in this region are limited. We reconstruct a GLOF that affected a small village in Chilean Patagonia in March 1977, by semi structured interviews, interpretation of satellite images and 2D hydraulic modelling. This provides insight into the GLOF dynamics and the planning issues that led to socioeconomic consequences, which included village relocation. Modelling shows that the water released by the GLOF was in the order of 12-13 × 10(6)m(3) and the flood lasted for about 10h, reaching a maximum depth of ~1.5m in Bahía Murta Viejo, ~ 26 km from the failed lake. The lake had characteristics in common with failed lakes worldwide (e.g. the lake was in contact with a retreating glacier and was dammed by a narrow-steep moraine). The absence of land-use planning and the unawareness of the GLOF hazard contributed to the village flooding. The Río Engaño GLOF illustrates how small-scale and short-distance migration is a reasonable coping strategy in response to a natural hazard that may increase in frequency as atmospheric temperature rises and glaciers retreat.

  1. Investigación sobre manejo forestal a largo plazo en Patagonia Sur -Argentina: Lecciones del pasado, desafíos del presente Long-term forest management research in South Patagonia - Argentina: Lessons from the past, challenges from the present

    Directory of Open Access Journals (Sweden)

    GUILLERMO J MARTÍNEZ-PASTUR

    2010-03-01

    Full Text Available Argentina ha basado su economía en la agricultura y el ganado, donde el bosque ha sido visto como un obstáculo para el desarrollo. La cosecha forestal en Patagonia Sur ha sido una actividad basada en la colonización y explotación de nuevas áreas. Esta se realiza principalmente en bosques primarios sin ningún manejo silvícola posterior. A pesar de que el manejo actual no es sustentable, la investigación científica ha definido las bases para conservar, proteger y mejorar las propuestas de manejo forestal para los bosques nativos de Patagonia Sur. Las primeras parcelas de estudio a largo plazo (1965-1966 basaron su monitoreo en parámetros económicos y estructura forestal, estableciéndose cerca de veinte parcelas en bosques fiscales de Tierra del Fuego. La mayoría fueron destruidas o discontinuadas debido a la falta de planificación del uso de la tierra, escaso interés social en la investigación, falta de compromiso de instituciones, y poca colaboración con empresas forestales. Posteriormente, un segundo grupo de nueve parcelas se estableció en Patagonia Sur (1993-2004 basado en la colaboración entre empresas privadas e instituciones nacionales. Los objetivos incluyeron parámetros económicos y ecológicos. Las parcelas se establecieron en tierras privadas conjuntamente con empresas privadas y estancieros, mediante la firma de acuerdos y proyectos de investigación. Los principales problemas encontrados fueron: falta de compromiso de las administraciones forestales, ausencia de proyectos financiados a largo plazo, y que la responsabilidad de las parcelas continúa bajo la iniciativa personal de los investigadores participantes. El estudio de las parcelas permitió: (i proponer nuevos sistemas de regeneración basados en la maximización del rendimiento y el mejoramiento del valor de conservación de los bosques manejados (e.g., retención variable y sistemas silvopastoriles, (ii determinar la factibilidad económica de aplicaci

  2. CAMBIOS EN EL TAMAÑO DE EXOESQUELETOS CALCÁREOS DE MOLUSCOS DURANTE EL HOLOCENO TARDÍO: ARQUEOMALACOLOGÍA DE CONCHEROS EN LA COSTA NORTE DE SANTA CRUZ, PATAGONIA ARGENTINA (Size Change of Calcareous Exoskeletons of Molluscs during the Late Holocene: Archaeomalacology of Shell Middens on the Northern Coast of Santa Cruz, Patagonia, Argentina

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    Heidi Hammond

    2016-12-01

    Full Text Available En la costa norte de Santa Cruz, Patagonia Argentina, los concheros son una de las evidencias arqueológicas de ocupación por cazadores-recolectores. Se realizaron estudios biométricos sobre exoesqueletos calcáreos de moluscos recuperados en concheros con el fin de evaluar la existencia de una tendencia/patrón de cambio en el tamaño a lo largo del tiempo. Los resultados permitieron reconocer una reducción en el tamaño medio de las conchas a lo largo del Holoceno tardío. Se discuten las implicancias paleoambientales, ecológicas y/o culturales. Finalmente, se avanza en la discusión sobre la dinámica de ocupación humana y el uso de los recursos. ENGLISH: On the northern coast of Santa Cruz, Patagonia, Argentina, shell middens form part of the archaeological evidence for hunter-gatherer occupation. We performed biometric studies on calcareous exoskeletons of molluscs recovered in shell middens in order to evaluate the existence of a trend or pattern of size change over time. The results allowed us to recognize a reduction in size change over the course of the late Holocene. We discuss the paleoenvironmental, ecological and/or cultural implications of these findings. Finally, we relate the discussion to the dynamics of human occupation and resource use.

  3. Diseño de obras de control de aluviones basada en simulación de procesos hidrológicos torrenciales en cuencas de la Patagonia Design of alluvium control structures based on flash flood simulation in the Patagonia basins

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    Ana Cecilia Dufilho

    2001-05-01

    Full Text Available Fenómenos climáticos torrenciales que producen aluviones y grandes movimientos de sedimentos (bajo distintas formas son muy frecuentes en la Patagonia Argentina. Los estudios para el diseño de obras de control se realizan en general, a través de fórmulas empíricas sin verificar su aptitud a las condiciones patagónicas. En el presente trabajo se utilizan modelos matemáticos sencillos para la simulación hidrológica de crecidas en cuencas con escasa información hidrometeorológica y nula instrumentación. Esta metodología requiere estimar la lluvia de diseño asumiendo un nivel de riesgo, evaluar la eficiencia de distintos planes de control mediante simulaciones de distintas alternativas de obras y seleccionar aquella de menor costo.Climatic processes leading to flash flood and large sediment movements (under different forms are very frequent in Patagonia, Argentina. Often, projects of small reservoirs and levees are based on empirical formulations without a verification of their aptitude to the local conditions. In the present work, simple flood mathematical models are used for hydrological simulation in basins with scarce precipitation and flood data. This methodology requires estimation of the design storm associated with a risk level. It allows simulation and evaluation of alternative control projects, facilitating the selection of the least cost control scheme.

  4. Photovoltaic systems in Patagonia

    Energy Technology Data Exchange (ETDEWEB)

    Lawand, T.A. [McGill Univ., Ste. Anne de Bellevue, PQ (Canada). Brace Research Inst., Macdonald Coll; Rapallini, A. [MR Consultores, Buenos Aires, (Argentina); Pedro, G. [Ente Provincial de Energia del Neuquen, Neuquen, (Argentina)

    1998-05-01

    The feasibility of using of solar photovoltaic (PV) systems in the remote cold areas of the Neuquen province in Argentina was discussed. A program was developed by the local public utility to provide schools with electricity using photovoltaic panels. The PV systems have replaced expensive diesel generators which had become unreliable. In the first phase of the program, 27 schools were electrified using photovoltaic panels, battery storage systems and simple control panels. A review of the performance of the system components under the harsh climatic conditions of the region was discussed. The program has been expanded to include about 50 family systems. Another 150 are projected for the near future. 3 refs., 2 figs., 3 tabs.

  5. Glaciation and topographic evolution of the Central Patagonian Andes since 6 Ma

    Science.gov (United States)

    Christeleit, E. C.; Laemel, R.; De Wolf, W. E.; Shuster, D. L.; Brandon, M. T.

    2013-12-01

    New and existing thermochronological data are used to model glacial erosion and topographic evolution of the central Patagonian Andes (~47S) over the last 6 Ma. The modern Andes are cut by large valleys and fjords with local valley relief of at least 2.5 km. It is currently thought that a formerly uniformly high Andes was 'buzzed' down to the elevation of the equilibrium line altitude, presumably in the last 2 Ma concurrent with late Cenozoic global cooling. However, studies of glacial debris show that glaciers were present in Patagonia as early as 6 Ma. The extent of these early glaciations is unclear, but recent work suggests that glacial valleys in the central Patagonian Andes were carved at a steady rate beginning at 6 Ma, implying that valley incision may be an important process in the topographic evolution of glaciated mountain ranges, rather than cirque retreat. To understand how valley relief has formed in the Andes, we dated 30 samples from Steffen Fjord in Chile using apatite (U-Th)/He thermochronology. We use this new data and existing thermochronological data in the region to estimate the topographic form of the central Andes at 6 Ma and model how the valley relief has evolved since the initiation of glaciation using Pecube.

  6. Sequential development of tidal ravinement surfaces in macro- to hypertidal estuaries with high volcaniclastic input: the Miocene Puerto Madryn Formation (Patagonia, Argentina)

    Science.gov (United States)

    Scasso, Roberto A.; Cuitiño, José I.

    2016-12-01

    The late Miocene beds of the Puerto Madryn Formation (Provincia del Chubut, Argentina) are formed by shallow marine and estuarine sediments. The latter include several tidal-channel infills well exposed on the cliffy coast of the Peninsula Valdés. The Bahía Punta Fósil and Cerro Olazábal paleochannels are end members of these tidal channels and show a fining-upward infilling starting with intraformational channel lag conglomerates above deeply erosional surfaces interpreted as fluvial ravinement surfaces (the erosion surface formed in the purely fluvial or the fluvially dominated part of the estuary, where erosion is driven by fluvial processes). These are overlain and eventually truncated (and suppressed) by the tidal ravinement surface (TRS), in turn covered with high-energy, bioclastic conglomerates mostly formed in the "tidally dominated/fluvially influenced" part of an estuary. Above, large straight or arcuate point bars with alternatively sandy/muddy seasonal beds and varying trace and body fossil contents were deposited from the freshwater fluvially dominated to saline-water tidally dominated part of the estuary. The upper channel infill is formed by cross-bedded sands with mud drapes and seaward-directed paleocurrents, together with barren, volcaniclastic sandy to muddy heterolithic seasonal rhythmites, both deposited in the fluvially dominated part of the estuary. Volcanic ash driven by the rivers after large explosive volcanic eruptions on land resulted in sedimentation rates as high as 0.9 m per year, preserving (through burial) the morphology of tidal channels and TRSs. The channel deposits were formed in a tide-dominated, macrotidal to hypertidal open estuary with well-developed TRSs resulting from strong tidal currents deeply scouring into the transgressive filling of the channels and eventually cutting the fluvial ravinement surface. The TRSs extended upstream to the inner part of the estuary during long periods of low sedimentation rates

  7. El conocimiento geográfico de la Patagonia interior y la construcción de la imagen de Torres del Paine como patrimonio natural a conservar

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    Ferrer Jiménez, Daniel

    2009-06-01

    Full Text Available Torres del Paine National Park (12th Region, Chile, the Paine Massif and its surroundings are a major milestone concerning three issues: the perception of nature in the Patagonian-Andean environment, the first steps of conservationism in South America and the first scientific studies in this part of the planet. In addition, ever since scientists and travelers were to “discover” this region, Paine has been a benchmark of both the first proposals for nature tourism linked with conservationism, as well as a major challenge for alpine expeditions.

    Due to these circumstances, the doctoral dissertation of the author devotes one entire chapter to analysing the main contributions of the Paine phenomenon to the geographical knowledge of inland Patagonia and to the perception of Torres del Paine as a natural heritage worth preserving. This is precisely the subject of this paper, which gives an insight into the geographical reconnaissance explorations that took place between 1877 and 1896 in the Patagonian inland, under the initiatives of Chilean and Argentinean governments; the first known touristic travel in the Chilean region of Magallanes; the role of the first “visionaries” of Patagonian-Andean tourism in Chile, gathered around Werner Gromsch and the Touring Club; or the geographical, scientific and informative work carried out by Alberto Maria De Agostini. Finally, the article discusses the first alpine expeditions which targeted the summits of the Paine Massif.

    El Parque Nacional de las Torres del Paine (XII Región, Chile, el Macizo Paine y su entorno, constituye un hito en la imagen de la naturaleza del mundo andino patagónico, en los inicios del primer conservacionismo de América del Sur y en los estudios científicos sobre esa parte del Planeta. En relación con ello, además, el Paine ha sido, desde su “descubrimiento” científico y viajero hace más de un siglo, un referente fundamental de las

  8. Ash storms: impacts of wind-remobilised volcanic ash on rural communities and agriculture following the 1991 Hudson eruption, southern Patagonia, Chile

    Science.gov (United States)

    Wilson, T. M.; Cole, J. W.; Stewart, C.; Cronin, S. J.; Johnston, D. M.

    2011-04-01

    Tephra fall from the August 1991 eruption of Volcán Hudson affected some 100,000 km2 of Patagonia and was almost immediately reworked by strong winds, creating billowing clouds of remobilised ash, or `ash storms'. The immediate impacts on agriculture and rural communities were severe, but were then greatly exacerbated by continuing ash storms. This paper describes the findings of a 3-week study tour of the diverse environments of southern Patagonia affected by ash storms, with an emphasis on determining the impacts of repeated ash storms on agriculture and local practices that were developed in an attempt to mitigate these impacts. Ash storms produce similar effects to initial tephra eruptions, prolonged for considerable periods. These have included the burial of farmland under dune deposits, abrasion of vegetation and contamination of feed supplies with fine ash. These impacts can then cause problems for grazing animals such as starvation, severe tooth abrasion, gastrointestinal problems, corneal abrasion and blindness, and exhaustion if sheep fleeces become laden with ash. In addition, ash storms have led to exacerbated soil erosion, human health impacts, increased cleanup requirements, sedimentation in irrigation canals, and disruption of aviation and land transport. Ash deposits were naturally stabilised most rapidly in areas with high rainfall (>1,500 mm/year) through compaction and enhanced vegetation growth. Stabilisation was slowest in windy, semi-arid regions. Destruction of vegetation and suppression of regrowth by heavy tephra fall (>100 mm) hindered the stabilisation of deposits for years, and reduced the surface friction which increased wind erosivity. Stabilisation of tephra deposits was improved by intensive tillage, use of windbreaks and where there was dense and taller vegetative cover. Long-term drought and the impracticality of mixing ash deposits with soil by tillage on large farms was a barrier to stabilising deposits and, in turn

  9. Magnetic fabric and microstructures of Late Paleozoic granitoids from the North Patagonian Massif: Evidence of a collision between Patagonia and Gondwana?

    Science.gov (United States)

    López de Luchi, Mónica G.; Rapalini, Augusto E.; Tomezzoli, Renata N.

    2010-10-01

    Widespread Late Paleozoic magmatism in northern Patagonia is a target to test hypotheses on the long standing question over the origin of Patagonia. In recent years, a dispute over whether it is an accreted crustal block that collided with Gondwana in Paleozoic times or an autochthonous part of South America has taken place. As part of a multidisciplinary study, an integrated microstructural and magnetic fabric study was carried out on the Late Carboniferous Yaminué Complex and the Early Permian Navarrete Plutonic Complex, both exposed in the northeastern corner of the North Patagonian Massif (40.5°S, 67.0°W). Other investigated units are the Late Carboniferous Tardugno Granodiorite, the newly defined Cabeza de Vaca Granite and the Late Permian San Martin pluton. Over 300 oriented cores from 60 sites were collected for anisotropy of magnetic susceptibility (AMS) measurements. A systematic analysis of around 100 petrographic thin sections was performed to characterize the microstructures of the different magmatic units. Microstructures in the Yaminué Complex are indicative of a transition from magmatic to solid-state deformation. Microstructures of the orthogneiss of tonalitic composition suggest an early stage in the emplacement history of this complex. The Cabeza de Vaca Granite, intrusive in Yaminué Complex, is the most evolved unit and records less intense high-temperature solid-state deformation which suggests that the stress field that controlled the emplacement of the Yaminué Complex outlasted it. According to petrologic and structural considerations, the Navarrete Plutonic Complex has been subdivided into three facies, i.e. Robaina, Guanacos and Aranda, respectively. Microstructures of the Navarrete Plutonic Complex are mostly magmatic to submagmatic, versus the solid-state fabric that characterizes the Robaina facies at the contact with the Yaminué Complex. Combined analyses of AMS and microstructural data lead us to suggest that the Yaminué Complex

  10. Jurassic cooling ages in Paleozoic to early Mesozoic granitoids of northeastern Patagonia: 40Ar/39Ar, 40K-40Ar mica and U-Pb zircon evidence

    Science.gov (United States)

    Martínez Dopico, Carmen I.; Tohver, Eric; López de Luchi, Mónica G.; Wemmer, Klaus; Rapalini, Augusto E.; Cawood, Peter A.

    2016-12-01

    U-Pb SHRIMP zircon crystallization ages and Ar-Ar and K-Ar mica cooling ages for basement rocks of the Yaminué and Nahuel Niyeu areas in northeastern Patagonia are presented. Granitoids that cover the time span from Ordovician to Early Triassic constitute the main outcrops of the western sector of the Yaminué block. The southern Yaminué Metaigneous Complex comprises highly deformed Ordovician and Permian granitoids crosscut by undeformed leucogranite dikes (U-Pb SHRIMP zircon age of 254 ± 2 Ma). Mica separates from highly deformed granitoids from the southern sector yielded an Ar-Ar muscovite age of 182 ± 3 Ma and a K-Ar biotite age of 186 ± 2 Ma. Moderately to highly deformed Permian to Early Triassic granitoids made up the northern Yaminué Complex. The Late Permian to Early Triassic (U-Pb SHRIMP zircon age of 252 ± 6 Ma) Cabeza de Vaca Granite of the Yaminué block yielded Jurassic mica K-Ar cooling ages (198 ± 2, 191 ± 1, and 190 ± 2 Ma). At the boundary between the Yaminué and Nahuel Niyeu blocks, K-Ar muscovite ages of 188 ± 3 and 193 ± 5 Ma were calculated for the Flores Granite, whereas the Early Permian Navarrete granodiorite, located in the Nahuel Niyeu block, yielded a K-Ar biotite age of 274 ± 4 Ma. The Jurassic thermal history is not regionally uniform. In the supracrustal exposures of the Nahuel Niyeu block, the Early Permian granitoids of its western sector as well as other Permian plutons and Ordovician leucogranites located further east show no evidence of cooling age reset since mica ages suggest cooling in the wake of crystallization of these intrusive rocks. In contrast, deeper crustal levels are inferred for Permian-Early Triassic granitoids in the Yaminué block since cooling ages for these rocks are of Jurassic age (198-182 Ma). Jurassic resetting is contemporaneous with the massive Lower Jurassic Flores Granite, and the Marifil and Chon Aike volcanic provinces. This intraplate deformational pulse that affected northeastern

  11. Una expedición a la "frontera" a comienzos del siglo XX: la Patagonia em las crónicas de Roberto Arlt

    Directory of Open Access Journals (Sweden)

    Mariela Eva Rodríguez

    2003-07-01

    Full Text Available En 1934, Roberto Arlt emprende un viaje hacia las provincias argentinas de Río Negro y Neuquén, con el objetivo de escribir notas - a las que el autor llama "Aguafuertes" - para su columna en el diario El Mundo. Deseo responder aquí a tres preguntas: a ¿desde qué posiciones discursivas enuncia el autor?, b ¿cómo construye el espacio de su desplazamiento entre un "aquí", Buenos Aires, y un "allí", la Patagonia, a la que refiere como una "frontera en el más amplio sentido de la palabra"? y c ¿cuáles son las tensiones subyacentes entre la aceptación del discurso hegemónico, que prioriza la idea de "civilización", y las posibles respuestas contra-hegemónicas?. Mediante su crónica, Arlt se vuelve vocero que denuncia el abandono del estado nacional, así como la miseria y explotación de los sectores más vulnerables, entre los que se destacan los indígenas y los chilotes - trabajadores migrantes de la isla de Chiloé.In 1934, Roberto Arlt undertook a trip to the Argentinian provinces of Río Negro and Neuquén, with the goal of writing notes - that he calls "Aguafuertes" - for his column in the newspaper El Mundo (The World. I wish here to answer three questions: a Which are the enunciation positions used by the author?, b How does he construct the space of his displacement between a "here," Buenos Aires, and a "there," Patagonia, which is depicted as a "frontier in the widest sense of the word"?, and c Which are the underling tensions between the acceptation of the hegemonic discourse, which focuses on the idea of "civilization," and the possible contra-hegemonic answers?. Through his chronicle, Arlt becomes a spokesperson who denunciates the abandonment carried out by the national state, as well as the misery and exploitation suffered by the most vulnerable sectors, especially the indigenous and the chilotes - migrant workers from the island of Chiloé.

  12. Distribución de macroinvertebrados (Plecoptera y Aeglidae en ecosistemas fluviales de la Patagonia chilena: ¿Muestran señales biológicas de la evolución geomorfológica postglacial? Distribution of macroinvertebrates (Plecoptera and Aeglidae in fluvial ecosystems of the Chilean Patagonia: Do they show biological signals of the postglacial geomorphological evolution?

    Directory of Open Access Journals (Sweden)

    CLAUDIO VALDOVINOS

    2010-06-01

    Full Text Available La Patagonia chilena incluye uno de los sistemas hídricos más complejos de Sudamérica y uno de los menos intervenidos del mundo, los cuales fueron intensamente modelados por la actividad glacial del Cuaternario. El objetivo de este estudio fue determinar si en esta área existen zonas de endemismo de macroinvertebrados bentónicos fluviales y analizar los patrones de diversidad de organismos de alta (Plecoptera y baja vagilidad (Aeglidae. Entre el 2006 y 2009 se muestrearon 183 sitios entre 42°50' y 54°43' S, focalizándose en las principales cuencas. Los muéstreos se realizaron con una red "kicknet", cubriendo una superficie de fondo de 8 m². En toda el área se registraron 30 especies de Plecoptera y dos de Aeglidae. Se identificó una zona de endemismo en la cuenca del río Aysén, sustentada por el plecóptero Ceratoperla fazi y el cangrejo Aegla neuquensis. Esta última especie correspondería a una población relictual procedente de los ríos de la estepa Argentina, que habría quedado atrapada en la Patagonia chilena, luego que se invirtiera el flujo del cauce del río que originalmente fluía hacia el Atlántico. Un marcado cambio latitudinal en la diversidad de especies fue evidente a lo largo del área de estudio (R² = 0.72, P The Chilean Patagonia includes one of the most complex hydrological systems of South America and one of the least modified systems of the world. These systems were intensely modified by the glacial activity of the Quaternary. The objectives of this study were to determine whether or not in this area exists zones of endemic benthic fluvial macroinvertebrates, and to analyze the patterns of diversity of species composed by organisms of high (Plecoptera and low (Aeglidae vagility. A collection of 183 selected sites, located between the latitude 42° 50' and 54°43' S, were sampled during 2006 and 2009. The sampling was focused on the main river basins and a "kicknet" was used to cover a surface of 8 m² at

  13. Charles Darwin and the oldestglacial events in Patagonia: the erratic blocks of the Río Santa Cruz valley Charles Darwin y las glaciacionesmás antiguas de Patagonia: los bloques erráticos del alto valle del Río Santa Cruz

    Directory of Open Access Journals (Sweden)

    Jorge Strelin

    2009-04-01

    Full Text Available Althoughthe depositational environment assigned by Darwin to the large erratic blocksand gravels in the Río Santa Cruz valley has been reinterpreted, hisgeomorphological and stratigraphic observations are still in force. The largeerratic blocks he described as crowning the Condor Cliff terrace and spread atthe bottom of the valley just east of this locality (Sites 2 and 3, are nowinterpreted as indicators of the maximum glacial expansion in Patagonia.Similar blocks, though of a different lithology, accumulated over a lowerterrace located up-valley (Site 4, are now linked to moraines and glacifluvialterraces of the Penultimate Glaciation. Finally, in addition to the erraticblock discovered by Darwin in the lower Río Santa Cruz valley (Site 1, thereare others - recently discovered - which probably account for a catastrophicevent ascribed to a big glacier-lake outburst during the last interglacial.No obstante haber sidoreinterpretado el ambiente depositacional asignado por Darwin a los grandesbloques erráticos y rodados del valle del río Santa Cruz, siguen vigentes susobservaciones geomorfológicas y estratigráficas. Los grandes bloques erráticosque describe coronando la terraza de Condor Cliff y dispersos en el fondo delvalle inmediatamente al este de esta localidad (Sitios 2 y 3, soninterpretados ahora como indicadores de la máxima expansión glaciaria de la Patagonia. Bloques similares, aunque de dispar litología, acumulados sobre una terraza másbaja situada río arriba (Sitio 4, se vinculan actualmente a morenas y terrazasglacifluviales de la Penúltima Glaciación. Finalmente, al bloque erráticodescubierto por Darwin en el tramo inferior del valle del río Santa Cruz (Sitio1, se le suman otros -de reciente descubrimiento- que probablemente den cuentade un evento catastrófico atribuible al vaciamiento de un gran lago glaciardurante el último interglaciar.

  14. Formación ética y ciudadana. Vicisitudes de la transformación curricular en la Patagonia Argentina

    Directory of Open Access Journals (Sweden)

    Isabelino A Siede

    2015-01-01

    Full Text Available ¿Qué tipo de educación ética y ciudadana ofrecen efectivamente las escuelas? En este artículo se analizan las prescripciones curriculares de formación ética y ciudadana en las escuelas de educación básica de la Patagonia argentina, y sus relaciones y contradicciones con las prácticas escolares de educación moral. Se indaga el proceso de definición del área en el contexto de la reforma educativa de los años noventa y busca reconstruir su modalidad de incorporación en el diseño curricular provincial de Santa Cruz, como expresión de las intenciones explícitas e implícitas de esa política curricular. A través de grupos focales y entrevistas a docentes de diferentes escuelas públicas y privadas de tres localidades del norte santacruceño, se analizan las descripciones, valoraciones y expectativas de los docentes sobre sus prácticas de enseñanza en el terreno moral, así como también las posibles causas de las distancias y contradicciones entre las políticas de enunciación curricular y las propuestas formativas que ofrecen las escuelas.

  15. Patagonia, de margen exótico a periferia turística. Una mirada sobre un área natural protegida de frontera

    Directory of Open Access Journals (Sweden)

    Paula Gabriela Núñez

    2012-01-01

    Full Text Available Durante la primera mitad del siglo XX la creación de los Parques Nacionales en la Argentina, ubicados en espacios periféricos de frontera, respondió a diferentes lógicas en una organización territorial previa del país. Para analizar el impacto e infl uencia de estas Áreas Naturales Protegidas (ANP se consideró como caso de estudio el Parque Nacional Nahuel Huapi (Patagonia Andina, Argentina. Se concluyó que el ordenamiento territorial centralizado de la Nación se consolidó, en el Nahuel Huapi, a través de la institucionalización de un Área Natural Protegida. Asimismo, el análisis de este proceso permitió identifi car diferentes enfoques desde los cuales se pensó el desarrollo local y el turismo a lo largo del tiempo, afectando el modo de concebir las ANP periféricas.

  16. Living in an estuary: Commerson's dolphin (Cephalorhynchus commersonii (Lacépède, 1804, habitat use and behavioural pattern at the Santa Cruz River, Patagonia, Argentina

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    Rocio Loizaga de Castro

    2013-11-01

    Full Text Available Commerson's dolphins, Cephalorhynchus commersonii, suffer bycatch in fisheries and are target of dolphin-watching activities along Patagonia. Here we described dolphins' habitat use and behavioural pattern at the estuary of Santa Cruz River. Behavioural observations were made from vantage points using a spotting scope. Boat surveys were conducted randomly from Puerto Santa Cruz to the mouth of the river to analyze the habitat use. The survey area was divided into 1 km² cells and characterized with depth and benthic slope. The described behaviours for the Commerson's dolphin were: travelling, slow travelling, milling, resting, socializing, stationary swimming and diving. A new behavioural context was assigned to diving, a behaviour that showed a high frequency during downing tide, suggesting a benthic foraging strategy. Additionally, we found a strong influence of the tide on Commerson's dolphin behaviour. Habitat use models indicated that dolphins prefer shallow water inside the estuary. The knowledge of the behavioural patterns and the habitat use of these endemic species, in this unexplored area, provide tools for management and conservation purposes.

  17. EXPLOTACIÓN DE ESPECIES VEGETALES EN LA PATAGONIA SEPTENTRIONAL: EL REGISTRO ARQUEOBOTÁNICO DE CUEVA HUENUL 1 (PROVINCIA DE NEUQUÉN, ARGENTINA

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    Carina Llano

    2013-01-01

    Full Text Available Se presenta el análisis de los restos vegetales provenientes del sitio Cueva Huenul 1, Provincia de Neuquén, Argentina, el cual aporta nuevos conocimientos sobre el proceso de poblamiento, la explotación del medio ambiente y el uso de los recursos vegetales. La secuencia cronológica del sitio abarca desde la transición Pleistoceno-Holoceno hasta tiempos recientes. Los restos arqueológicos podrían haber sido depositados por sociedades cazadoras-recolectoras. Los taxones recuperados corresponden a especies silvestres autóctonas, las cuales concuerdan con el paisaje regional, y a un taxón domesticado (Lagenaria sp.. Se aborda el análisis tafonómico a fin de evaluar la incidencia antrópica o natural en la formación del conjunto arqueobotánico estudiado. Finalmente, se integran estos resultados con los datos proporcionados por otros indicadores arqueológicos y paleoecológicos, permitiendo una primera caracterización de la subsistencia humana en la escala del sitio. La ampliación espacial de este análisis permitirá evaluar la variación en la subsistencia en diferentes ambientes del noroeste de Patagonia.

  18. Integrative taxonomic re-description of Halisarca magellanica and description of a new species of Halisarca (Porifera, Demospongiae) from Chilean Patagonia.

    Science.gov (United States)

    Willenz, Philippe; Ereskovsky, Alexander V; Lavrov, Dennis V

    2016-12-21

    A series of recent expeditions in fjords and canals of Southern Chilean Patagonia allowed the re-collection of Halisarca magellanica Topsent, 1901 and the discovery of a new species, Halisarca desqueyrouxae sp. nov. The material studied was collected at depths ranging from 3 to 30 m at latitudes comprised between 42° and 49°S. Both species share the same habitat and show a morphological plasticity, but differ in their colour. Halisarca magellanica is bright pink to whitish with three morphs whereas H. desqueyrouxae sp. nov. is light brown to beige with two morphs. An extensive investigation in TEM and SEM reveals several differences among cell types with inclusions between both species. Three distinct spherulous cells occur. Type 1 is shared by both species, Type 2 is occasional in H. magellanica but absent from H. desqueyrouxae sp. nov. Type 3 is rare in H. magellanica and occurs abundantly in half of the specimens of H. desqueyrouxae sp. nov. Granular cells are shared by both species but do not occur in all specimens. Microgranular cells are characteristic of H. magellanica. Both species also clearly differ by their endobiotic bacteria. Phylogenetic analysis of cox1 sequences places H. magellanica as a sister group to all other previously published Halisarca species sequences (9.1-9.7% difference) except H. harmelini, while H. desqueyrouxae sp. nov. is placed as a sister group to H. dujardini (2.3% difference).

  19. Monopolizar la violencia en una frontera colonial. Policías y militares en Patagonia austral (Argentina y Chile, 1870-1922

    Directory of Open Access Journals (Sweden)

    Alberto Harambour R.

    2016-01-01

    Full Text Available Este artículo analiza la monopolización de la violencia en el ciclo inicial de colonización de Patagonia austral para lo cual propone, primero, que la precariedad local de los Estados de Argentina y Chile descansó en la fuerza expansiva de la industria ganadera para la instalación de su sobe- ranía territorial; y segundo, que la clausura de la delimitación fronteriza solo se produjo en el verano de 1922, como resultado de la represión a la insurgencia obrera. A partir de una extensa investigación en fuentes oficiales y empresariales referidas a Santa Cruz, Magallanes y Tierra del Fuego, así como en la prensa local, se investiga y compara la presencia de la fuerza policial y militar en las subdivisiones administrativas del extremo sur; además se examinaron similitudes y diferencias en las estra- tegias de control social.

  20. Baseline element composition of foliose and fruticose lichens along the steep climatic gradient of SW Patagonia (Aisén Region, Chile).

    Science.gov (United States)

    Monaci, Fabrizio; Fantozzi, Federica; Figueroa, Ricardo; Parra, Oscar; Bargagli, Roberto

    2012-09-01

    Samples of foliose (Nephroma antarcticum) and fruticose (Usnea sp.) lichens were collected across a steep climatic and vegetation gradient in a remote, almost pristine region of SW Chilean Patagonia. Concentrations of major and trace elements in lichens from the rainforest were among the lowest ever reported worldwide for foliose and fruticose lichens and can be considered background levels for the region. The two lichen growth forms showed different elemental compositions mainly due to the greater capacity of foliose thalli to intercept elements from windborne and canopy-leached particles. The patterns of spatial variation in the chemical composition of lichens were effectively explained by statistical methods and reflected the different availability of wet and dry deposition along the steep climatic gradient. Baseline values established for N. antarcticum samples growing in temperate Nothofagus forests were therefore distinct from those of samples growing in more open, drier habitats. The fruticose Usnea sp. showed a higher affinity for atmophile Hg, low concentrations of lithophilic elements, and the same baseline composition whether from temperate forests or from dry, barren environments. The provided background and baseline values against which variations can be measured will be useful in the early detection of local or regional climatic and environmental change, especially in view of the planned construction of hydropower dams under the recently approved HidroAysén Project.

  1. Central bank Financial Independence

    OpenAIRE

    J.Ramon Martinez-Resano

    2004-01-01

    Central bank independence is a multifaceted institutional design. The financial component has been seldom analysed. This paper intends to set a comprehensive conceptual background for central bank financial independence. Quite often central banks are modelled as robot like maximizers of some goal. This perspective neglects the fact that central bank functions are inevitably deployed on its balance sheet and have effects on its income statement. A financially independent central bank exhibits ...

  2. Aproximaciones al análisis de los conflictos ambientales en la Patagonia: reflexiones de historia reciente 1980-2005 Evaluation of environmental conflicts analyses in Patagônia: reflections on the recent history (1980-2005

    Directory of Open Access Journals (Sweden)

    Daniel Norberto Blanco

    2006-12-01

    Full Text Available Este texto trata de una historia social del ambiente en la región de Patagonia, en especial las discusiones sobre el presente y el futuro de la región. En el trabajo confluyen tres líneas de reflexión. La primera consiste en el análisis de los conflictos ambientales de la historia reciente de la Patagonia. La segunda línea de reflexión resulta de una mirada a la protesta social ante emprendimientos que pusieron en riesgo el ambiente. La tercera línea de reflexión hace una discusión acerca del cambio de representaciones sobre la Patagonia, sobre el ambiente y el territorio. Considerando que se trata de un territorio sometido al despojo y a la extracción desde su conquista militar se tratará de explicar por qué en las últimas décadas se verifica un ejercicio activo de la ciudadanía en defensa del ambiente.The article deals with a social history of environment in the region of Patagônia and is especially focused on the present and the future of the region. Three different lines of reflections are examined. The first is the analysis of the environmental conflicts in the recent history of Patagônia. The second is a look at the protest movements against businesses in the region that risk the environment A third line of reflection discusses the changes in the representations of Patagônia, environment and territory. The article also gives an explanation of why an active citizenship movement in defense of the environment has taken place in the past decades, considering that Patagônia is a territory that has been exploited since its military conquest.

  3. Population regulation in Magellanic penguins: what determines changes in colony size?

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    Luciana M Pozzi

    Full Text Available Seabirds are often studied at individual colonies, but the confounding effects of emigration and mortality processes in open populations may lead to inappropriate conclusions on the mechanisms underlying population changes. Magellanic penguin (Spheniscus magellanicus colonies of variable population sizes are distributed along the Argentine coastline. In recent decades, several population and distributional changes have occurred, with some colonies declining and others newly established or increasing. We integrated data of eight colonies scattered along ∼600 km in Northern Patagonia (from 41°26´S, 65°01´W to 45°11´S, 66°30´W, Rio Negro and Chubut provinces and conducted analysis in terms of their growth rates, production of young and of the dependence of those vital rates on colony age, size, and location. We contrasted population trends estimated from abundance data with those derived from population modeling to understand if observed growth rates were attainable under closed population scenarios. Population trends were inversely related to colony size, suggesting a density dependent growth pattern. All colonies located in the north--which were established during the last decades--increased at high rates, with the smallest, recently established colonies growing at the fastest rate. In central-southern Chubut, where colonies are the oldest, the largest breeding aggregations declined, but smaller colonies remained relatively stable. Results provided strong evidence that dispersal played a major role in driving local trends. Breeding success was higher in northern colonies, likely mediated by favorable oceanographic conditions. However, mean foraging distance and body condition of chicks at fledging were influenced by colony size. Recruitment of penguins in the northern area may have been triggered by a combination of density dependence, likely exacerbated by less favorable oceanographic conditions in the southern sector. Our results

  4. Population regulation in Magellanic penguins: what determines changes in colony size?

    Science.gov (United States)

    Pozzi, Luciana M; García Borboroglu, Pablo; Boersma, P Dee; Pascual, Miguel A

    2015-01-01

    Seabirds are often studied at individual colonies, but the confounding effects of emigration and mortality processes in open populations may lead to inappropriate conclusions on the mechanisms underlying population changes. Magellanic penguin (Spheniscus magellanicus) colonies of variable population sizes are distributed along the Argentine coastline. In recent decades, several population and distributional changes have occurred, with some colonies declining and others newly established or increasing. We integrated data of eight colonies scattered along ∼600 km in Northern Patagonia (from 41°26´S, 65°01´W to 45°11´S, 66°30´W, Rio Negro and Chubut provinces) and conducted analysis in terms of their growth rates, production of young and of the dependence of those vital rates on colony age, size, and location. We contrasted population trends estimated from abundance data with those derived from population modeling to understand if observed growth rates were attainable under closed population scenarios. Population trends were inversely related to colony size, suggesting a density dependent growth pattern. All colonies located in the north--which were established during the last decades--increased at high rates, with the smallest, recently established colonies growing at the fastest rate. In central-southern Chubut, where colonies are the oldest, the largest breeding aggregations declined, but smaller colonies remained relatively stable. Results provided strong evidence that dispersal played a major role in driving local trends. Breeding success was higher in northern colonies, likely mediated by favorable oceanographic conditions. However, mean foraging distance and body condition of chicks at fledging were influenced by colony size. Recruitment of penguins in the northern area may have been triggered by a combination of density dependence, likely exacerbated by less favorable oceanographic conditions in the southern sector. Our results reaffirm the idea that

  5. NIDDK Central Repository

    Data.gov (United States)

    U.S. Department of Health & Human Services — The NIDDK Central Repository stores biosamples, genetic and other data collected in designated NIDDK-funded clinical studies. The purpose of the NIDDK Central...

  6. Central Neuropathic Pain Syndromes.

    Science.gov (United States)

    Watson, James C; Sandroni, Paola

    2016-03-01

    Chronic pain is common in patients with neurologic complications of a central nervous system insult such as stroke. The pain is most commonly musculoskeletal or related to obligatory overuse of neurologically unaffected limbs. However, neuropathic pain can result directly from the central nervous system injury. Impaired sensory discrimination can make it challenging to differentiate central neuropathic pain from other pain types or spasticity. Central neuropathic pain may also begin months to years after the injury, further obscuring recognition of its association with a past neurologic injury. This review focuses on unique clinical features that help distinguish central neuropathic pain. The most common clinical central pain syndromes-central poststroke pain, multiple sclerosis-related pain, and spinal cord injury-related pain-are reviewed in detail. Recent progress in understanding of the pathogenesis of central neuropathic pain is reviewed, and pharmacological, surgical, and neuromodulatory treatments of this notoriously difficult to treat pain syndrome are discussed.

  7. Central venous catheter - flushing

    Science.gov (United States)

    ... during cancer treatment Bone marrow transplant - discharge Central venous catheter - dressing change Peripherally inserted central catheter - flushing Sterile technique Surgical wound care - open Review Date 9/22/2016 Updated by: ...

  8. A 1500 yr warm-season temperature record from varved Lago Plomo, Northern Patagonia (47° S) and implications for the Pacific Decadal Oscillation (PDO)

    Science.gov (United States)

    Elbert, J.; Jacques-Coper, M.; Van Daele, M.; Urrutia, R.; Grosjean, M.

    2013-04-01

    High-resolution records of calibrated proxy data for the past 2000 yr are fundamental to place current changes into the context of pre-industrial natural forced and unforced variability. Although the need for regional spatially explicit comprehensive reconstructions is widely recognized, the proxy data sources are still scarce, particularly for the Southern Hemisphere and South America. We provide a 1500 yr long warm season temperature record from varved Lago Plomo, a proglacial lake of the Northern Patagonian Ice field in southern Chile (46°59' S, 72°52' W, 203 m). The thickness of the bright summer sediment layer relative to the dark winter layer (measured as total brightness; % reflectance 400-730 nm) is calibrated against warm season SONDJF temperature (1900-2009; r = 0.58, p(aut) = 0.056, RE = 0.52; CE = 0.15, RMSEP = 0.28 °C; five-year triangular filtered data). In Lago Plomo, warm summer temperatures lead to enhanced glacier melt and suspended sediment transport, which results in a thicker light summer layer and to brighter sediments (% total brightness). Although Patagonia shows pronounced regional differences in decadal temperature trends and variability, the 1500 yr temperature reconstruction from Lago Plomo compares favourably with other regional/continental temperature records but also emphasizes significant regional differences for which no data and information existed so far. The reconstruction shows pronounced sub-decadal-multi-decadal variability with cold phases in the 5th, 7th and 9th centuries, during parts of the Little Ice Age chronozone (16th and 18th centuries) and in the beginning of the 20th century. The most prominent warm phase is the 19th century which is as warm as the second half of the 20th century, emphasizing a delayed recent global warming in the Southern Hemisphere. The comparison between winter precipitation and summer temperature (inter-seasonal coupling) from Lago Plomo reveals alternating phases with parallel and

  9. Relative paleointensity of the geomagnetic field over the last 4,500 years BP from sediment cores of Laguna Chaltel (Patagonia, Argentina)

    Science.gov (United States)

    Gogorza, C. G.; Irurzun, M. A.; Sinito, A. M.; Aldana, M.; Fey, M.; Ohlendorf, C.; Zolitschka, B.

    2013-05-01

    One motivation to investigate the magnetism of rocks is to study the behaviour of Earth's magnetic field of the past. The magnetic field is a vector field, having both direction and intensity. A complete understanding of it requires the study of all vector properties. However, paleointensity determinations are much more difficult than directions alone. This is one reason why the majority of paleomagnetic studies is concerned only with the directional variability of the magnetic field. Four short gravity cores from Laguna Chaltel in Patagonia, Argentina (49° 57'S, 71° 06'W) have been used to estimate the regional geomagnetic paleointensity. Measurements of intensity and directions of Natural Remanent Magnetization (NRM), magnetic susceptibility (k), isothermal remanent magnetization (IRM), saturation isothermal remanent magnetization (SIRM), as well as back field and anhysteretic remanent magnetization at 100 mT (ARM100mT) were performed and associated parameters calculated (ARM100mT/k, SIRM/ ARM100mT). In order to identify the magnetic mineralogy of the samples, IRM curves of a group of pilot samples were decomposed applying a Direct Signal Analysis (DSA) (Aldana et al., 2011). Results indicate the presence of magnetite, with logB1/2=1.8 and a relative proportion of 80%. Two other magnetic phases are observed at lower and higher logB1/2 values, probably greigite and goethite, respectively. DSA also indicates that the relative proportion of these minerals is the same in all samples analyzed. Studies also show that the magnetic grain size varies between 1 and 8 μm and that their concentration is between 0.01 and 0.08%. This range of the studied parameters indicates that our samples are suitable for paleointensity studies. The remanent magnetization at 15 mT (NRM15mT) has been normalized using the anhysteretic remanent magnetization at 15 mT (ARM15 mT), the saturation of isothermal remanent magnetization at 15 mT (SIRM15mT) and low field magnetic susceptibility (k

  10. A 1500 yr warm-season temperature record from varved Lago Plomo, Northern Patagonia (47° S and implications for the Pacific Decadal Oscillation (PDO

    Directory of Open Access Journals (Sweden)

    J. Elbert

    2013-04-01

    Full Text Available High-resolution records of calibrated proxy data for the past 2000 yr are fundamental to place current changes into the context of pre-industrial natural forced and unforced variability. Although the need for regional spatially explicit comprehensive reconstructions is widely recognized, the proxy data sources are still scarce, particularly for the Southern Hemisphere and South America. We provide a 1500 yr long warm season temperature record from varved Lago Plomo, a proglacial lake of the Northern Patagonian Ice field in southern Chile (46°59' S, 72°52' W, 203 m. The thickness of the bright summer sediment layer relative to the dark winter layer (measured as total brightness; % reflectance 400–730 nm is calibrated against warm season SONDJF temperature (1900–2009; r = 0.58, p(aut = 0.056, RE = 0.52; CE = 0.15, RMSEP = 0.28 °C; five-year triangular filtered data. In Lago Plomo, warm summer temperatures lead to enhanced glacier melt and suspended sediment transport, which results in a thicker light summer layer and to brighter sediments (% total brightness. Although Patagonia shows pronounced regional differences in decadal temperature trends and variability, the 1500 yr temperature reconstruction from Lago Plomo compares favourably with other regional/continental temperature records but also emphasizes significant regional differences for which no data and information existed so far. The reconstruction shows pronounced sub-decadal–multi-decadal variability with cold phases in the 5th, 7th and 9th centuries, during parts of the Little Ice Age chronozone (16th and 18th centuries and in the beginning of the 20th century. The most prominent warm phase is the 19th century which is as warm as the second half of the 20th century, emphasizing a delayed recent global warming in the Southern Hemisphere. The comparison between winter precipitation and summer temperature (inter-seasonal coupling from Lago Plomo reveals alternating phases with

  11. Improvement of isotope-based climate reconstructions in Patagonia through a better understanding of climate influences on isotopic fractionation in tree rings

    Science.gov (United States)

    Lavergne, Aliénor; Daux, Valérie; Villalba, Ricardo; Pierre, Monique; Stievenard, Michel; Srur, Ana Marina

    2017-02-01

    Very few studies of stable isotopes exist across the Andes in South America. This study is the first presenting annually resolved chronologies of both δ18 O and δ13 C in Nothofagus pumilio and Fitzroya cupressoides trees from Northern Patagonia. Interannual variability in δ18 O and δ13 C was assessed over the period 1952-2011. Based on these chronologies, we determined the primary climatic controls on stable isotopes and tree physiological responses to changes in atmospheric CO2 concentrations (ca), temperature and humidity. Changes in specific intrinsic water use efficiency (iWUE) were inferred from variations in δ13 C whereas the effects of CO2 increase on stomatal conductance were explored using δ18 O. Over the 60-year period, iWUE increased significantly (by ca. 25%) in coincidence with the rise of ca. The two species appear to have different strategies of gas-exchange. Whereas iWUE variations were likely driven by both stomatal conductance and photosynthetic assimilation rates in F. cupressoides, they were largely related to stomatal conductance in N. pumilio. After removing the low-frequency trends related to increasing ca, significant relationships between δ13 C and summer temperatures were recorded for both species. However, δ13 C variations in F. cupressoides were more strongly influenced by summer temperatures than in N. pumilio. Our results advocate for an indirect effect of summer temperatures on stable isotope ratios, which is mostly influenced by sunlight radiation in F. cupressoides and relative humidity/soil moisture in N. pumilio. δ13 C variations in F. cupressoides were spatially correlated to a large area south of 35°S in southern South America. These promising results encourage the use of δ13 C variations in F. cupressoides for reconstructing past variations in temperature and large-scale circulation indexes such as the Southern Annular Mode (SAM) in the Southern Hemisphere.

  12. Del Recurso Humano al humano con recursos: una propuesta en el estudio de encadenamientos socioproductivos para el Turismo de intereses especiales en el territorio Patagonia Verde Chile

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    Guillermo Sebastián Pacheco Habert

    2012-01-01

    Full Text Available El tema del humano con recurso, enfoque de este trabajo, tiene un papel importantísimo a la hora de transitar de estrategias competitivas hacia estrategias colaborativas, sobre todo cuando se perciben logros ecosocioeconómicos que avanzan hacia la dirección de un desarrollo territorial. Se tiene como hipótesis, que desde el enfoque de los encadenamientos socioproductivos, centrado en el turismo de intereses especiales, es posible comprender y establecer objetivos comunes dentro de actores, organizaciones, emprendimientos y comunidades locales. El objetivo de este artículo es proponer una aproximación teórica sobre el TIE (Turismo de Intereses Especiales sobre las aglomeraciones, sobre los encadenamientos socioproductivos y sobre el enfoque del humano con recurso, para posteriormente relatar los primeros resultados de esta investigación realizada en los cinco municipios que hacen parte del territorio turístico denominado "Patagonia Verde", en el sur de Chile. A partir de la identificación de actores clave, se aplicaron entrevistas a éstos y fichas de caracterización a emprendimientos. Posteriormente se identificaron fortalezas y oportunidades que puedan ser potenciadas a partir de la perspectiva del humano con recurso. A partir de los encadenamientos socioproductivos, contar con individuos conscientes y proactivos dentro de las instituciones y organizaciones en tareas y ejes estratégicos del desarrollo turístico y que compartan con la perspectiva del desarrollo territorial sustentable, es uno de los desafíos que aquí proponemos. Son los sujetos quienes son capaces de generar las condiciones institucionales para otra forma de comprender y actuar en Turismo.

  13. Modeling prey consumption by native and non-native piscivorous fishes: implications for competition and impacts on shared prey in an ultraoligotrophic lake in Patagonia

    Science.gov (United States)

    Juncos, Romina; Beauchamp, David A.; Viglianoc, Pablo H.

    2013-01-01

    We examined trophic interactions of the nonnative salmoni