WorldWideScience

Sample records for eastern sierras pampeanas

  1. Deformación cuaternaria asociada al frente de levantamiento oriental de las sierras de Velasco y Ambato, Sierras Pampeanas occidentales Quaternary deformation associated with the eastern uplift front of the Sierras de Velasco and Ambato, western Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    Analía L. Casa

    2010-12-01

    Full Text Available Sobre el frente oriental de la sierra de Velasco y extremo sur de la sierra de Ambato, Sierras Pampeanas Occidentales, se han hallado nuevas evidencias de actividad tectónica cuaternaria en cercanías de la ciudad de La Rioja. Los rasgos reconocidos corresponden a distintos tramos reactivados de las fallas que delimitan los frentes serranos y a estructuras que afectan los depósitos cuaternarios sobre el piedemonte. la sierra de Velasco Oriental se encuentra marginada por fallas de rumbo NNE e inclinación al ONO, mientras que la sierra de Ambato austral presenta estructuras de rumbo NE que inclinan al NO. En el bloque Carrizal estas direcciones se interfieren originando un sector de mayor complejidad estructural. La deformación observada evidencia la persistencia de un régimen compresivo durante el Cuaternario al que se asocian fallas inversas de vergencia oriental a sudoriental. Estas fallas continúan elevando los cordones serranos y constituyen potenciales fuentes sismogénicas.Along the eastern front of the Sierra de Velasco and at the southern end of the Sierra de Ambato, western Sierras Pampeanas, have been found new evidences of Quaternary tectonic activity near La Rioja city. Observed evidences correspond to different reactivated sections of the faults that bound the mountain fronts, as well as to structures affecting the Quaternary deposits on the piedmont. The bounding faults of the Sierra de Velasco Oriental-front exhibit a NNE trend and WNW dip, while structures at the southernmost Ambato range are characterized by NE trend and NW dip. The neotectonic faults of the El Carrizal block are the result of the interference of both structural trends, resulting in a sector with higher structural complexity. The here described deformation show the persistence of a compressive regime during the Quaternary, with eastern to southeastern verging reverse faults. It is considering that these faults are driving the current uplift of the mountain

  2. Anisotropy and Mantle Flow in the Eastern Sierras Pampeanas from Shear Wave Splitting

    Science.gov (United States)

    Wood, F. D.; Anderson, M. L.; Gilbert, H. J.; Alvarado, P. M.; Martino, R.

    2009-12-01

    The South American subduction zone has extreme examples of active flat-slab subduction and is believed to be an analog for subduction that occurred during the Cretaceous-Eocene age ("Laramide") mountain building events in the Western U.S. This region is therefore ideal for gaining a better understanding of shallow slab subduction and its influences on deformation of the surrounding mantle and overriding crust. Shear wave splitting analysis is used to test a model for the direction of mantle flow beneath the Eastern Sierras Pampeanas (ESP) in the Sierras de Córdoba region of Argentina to better understand the dynamics of flat-slab subduction. This study may also contribute to our understanding of the role the slab plays in deforming the overriding crust. The results of Anderson et al. (2004) indicate that the seismic fast directions underlying Chile and western Argentina are oriented N-S, or trench parallel. To the east, under the Sierras Pampeanas and coincident with a segment of flat subduction, the seismic fast direction is E-W, or trench perpendicular. Anderson et al. formulated several hypotheses to explain this apparent heterogeneity in the anisotropy. One explanation is that the retrograde motion of the subducting slab, caused by the westward movement of the overriding slab, prohibits E-W mantle flow, thus causing an overall N-S flow direction and the observed N-S oriented fast directions. The E-W oriented fast directions would then result from anisotropy due to mantle material being drawn into the area vacated by the slab as it is flattened. If this is the case, E-W fast directions should only be measured at stations directly above the flat slab. As alternative interpretations, the detected heterogeneous anisotropy may be due to strong lithospheric anisotropy or differences in the hydration state in the mantle. In the case of hydration state, E-W fast directions would be expected in the backarc south of the flat slab segment, where normal subduction occurs

  3. Regional polyphase deformation of the Eastern Sierras Pampeanas (Argentina Andean foreland): strengths and weaknesses of paleostress inversion

    Science.gov (United States)

    Traforti, Anna; Zampieri, Dario; Massironi, Matteo; Viola, Giulio; Alvarado, Patricia; Di Toro, Giulio

    2016-04-01

    The Eastern Sierras Pampeanas of central Argentina are composed of a series of basement-cored ranges, located in the Andean foreland c. 600 km east of the Andean Cordillera. Although uplift of the ranges is partly attributed to the regional Neogene evolution (Ramos et al. 2002), many questions remain as to the timing and style of deformation. In fact, the Eastern Sierras Pampeanas show compelling evidence of a long lasting brittle history (spanning the Early Carboniferous to Present time), characterised by several deformation events reflecting different tectonic regimes. Each deformation phase resulted in further strain increments accommodated by reactivation of inherited structures and rheological anisotropies (Martino 2003). In the framework of such a polyphase brittle tectonic evolution affecting highly anisotropic basement rocks, the application of paleostress inversion methods, though powerful, suffers from some shortcomings, such as the likely heterogeneous character of fault slip datasets and the possible reactivation of even highly misoriented structures, and thus requires careful analysis. The challenge is to gather sufficient fault-slip data, to develop a proper understanding of the regional evolution. This is done by the identification of internally consistent fault and fracture subsets (associated to distinct stress states on the basis of their geometric and kinematic compatibility) in order to generate a chronologically-constrained evolutionary conceptual model. Based on large fault-slip datasets collected in the Sierras de Cordoba (Eastern Sierras Pampeanas), reduced stress tensors have been generated and interpreted as part of an evolutionary model by considering the obtained results against: (i) existing K-Ar illite ages of fault gouges in the study area (Bense et al. 2013), (ii) the nature and orientation of pre-existing anisotropies and (iii) the present-day stress field due to the convergence of the Nazca and South America plates (main shortening

  4. Comparative seismic and petrographic crustal study between the Western and Eastern Sierras Pampeanas region (31°S

    Directory of Open Access Journals (Sweden)

    P. Alvarado

    2005-12-01

    Full Text Available The ancient Sierras Pampeanas in the central west part of Argentina are a seismically active region in the back-arc of the Andes. Their crystalline basement cored uplifts extend up to 800 km east of the oceanic trench over the flat subduction segment of the Nazca plate. Approximately 40 felt crustal earthquakes, are reported per year for this region. Historic and modern seismicity indicates that the Western Sierras Pampeanas (WSP have more crustal earthquakes of greater-size than the Eastern Sierras Pampeanas (ESP. Remarkable changes in composition and structure also characterize the WSP and ESP basements. We have quantitatively compared both regions using seismological constrains. A recent regional study of moderate earthquakes shows reverse and thrust focal mechanisms occurring at depths down to 25 km in the WSP. In contrast, the ESP have reverse and strike-slip focal mechanisms of shallower depths (< 10 km. A seismic velocity structure of Vp 6.4 km/s, Vp/Vs ~1.80, and thickness 50 km, best represents the WSP crust. The ESP crust is characterized by Vp 6.0 km/s, Vp/Vs < 1.70, and thickness 30 km. These seismological determinations correlate with the interpretation of a different origin for the western and eastern terranes. The WSP show seismic properties indicative of a more mafic-ultramafic thick crust consistent with an oceanic island-arc and back-arc formation. The ESP show crustal seismic properties consistent with a higher silica content and with a formation by the collision of a continental terrane.

  5. Los diques comendíticos de Papachacra (Catamarca: magmatismo peralcalino en sierras Pampeanas orientales The comenditic dikes from Papachacra (Catamarca: peralkaline magmatism in Eastern Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    Fernando Colombo

    2010-03-01

    genetically unrelated El Portezuelo granite. They have porphyritic texture and are composed of K feldspar (Or97-98 Ab2-3 and aegirine (Ac94-98 phenocrysts in an aphanitic groundmass of quartz, K feldspar, albite, aegirine and Li-bearing amphibole chemically related to fluor-ferro-leakeite. Minor accessory phases include ilmenite, magnetite, pyrochlore-group minerals, REE-rich epidote, zircon (interstitial, monazite-(Ce and an unidentified Nb-Y-Fe oxide. Their SiO2 content ranges between 68.28 and 69.33%, with very low Mg, Ca, Ba, Sr and Eu, and high concentrations of Nb (399-409 ppm, Ta (16-34 ppm, Th (46-84 ppm, Y (101-192 ppm, Zn (280-320 ppm, Ga (42-47 ppm and especially Zr (2324-3000 ppm. The comendites were intruded during a distensive magmatic event. A reconnaissance Rb-Sr isotopic study performed on related rocks indicates an age of 295 + 8 Ma, with an initial 87Sr/86Sr ratio of ca. 0.7041, pointing to a source from the sublithospheric mantle or the base of the lower crust. These rocks belong to the A1 class of A-type granites, suggesting an origin related to rifting or hot spots, and their trace element ratios show affinities with melts related to oceanic island basalts. In this respect, they are different from all the post-Devonian A-type granites described in Eastern Sierras Pampeanas.

  6. Comparative seismic and petrographic crustal study between the Western and Eastern Sierras Pampeanas region (31°S Estudio sísmico y petrográfico cortical comparativo entre las Sierras Pampeanas Occidentales y Orientales (31°S

    Directory of Open Access Journals (Sweden)

    P. Alvarado

    2005-12-01

    Full Text Available The ancient Sierras Pampeanas in the central west part of Argentina are a seismically active region in the back-arc of the Andes. Their crystalline basement cored uplifts extend up to 800 km east of the oceanic trench over the flat subduction segment of the Nazca plate. Approximately 40 felt crustal earthquakes, are reported per year for this region. Historic and modern seismicity indicates that the Western Sierras Pampeanas (WSP have more crustal earthquakes of greater-size than the Eastern Sierras Pampeanas (ESP. Remarkable changes in composition and structure also characterize the WSP and ESP basements. We have quantitatively compared both regions using seismological constrains. A recent regional study of moderate earthquakes shows reverse and thrust focal mechanisms occurring at depths down to 25 km in the WSP. In contrast, the ESP have reverse and strike-slip focal mechanisms of shallower depths (Los antiguos bloques montañosos de las Sierras Pampeanas del centro-oeste argentino constituyen una región sísmicamente activa en la zona andina de trasarco. Estos bloques de basamento cristalino afloran hasta 800 km al este de la trinchera oceánica sobre el segmento de subducción horizontal. Más de 40 sismos «sentidos», son reportados por año para esta región. La distribución de la sismicidad moderna e histórica, muestra que las Sierras Pampeanas Occidentales experimentan más sismos de mayor magnitud que las Sierras Pampeanas Orientales. Geológicamente, existen marcados contrastes en la composición litológica y estructura del basamento en ambas regiones. Un estudio sismológico reciente indica que las Sierras Pampeanas occidentales son más activas sísmicamente que las orientales, con mecanismos focales inversos que alcanzan profundidades de hasta 25 km. Las Sierras Pampeanas orientales presentan mecanismos focales inversos y de desplazamiento de rumbo con profundidades focales < 10 km. Diferentes estructuras corticales de

  7. Time constraints on the tectonic evolution of the eastern Sierras Pampeanas (Central Argentina)

    DEFF Research Database (Denmark)

    Siegesmund, Siegfried; Steenken, A; Martino, R D

    2010-01-01

    cycle in the neighbouring Sierra de San Luis and has not affected the titanite ages. The PTt evolution can be correlated with the plate tectonic processes responsible for the formation of the Pampean orogene, i.e., the accretion of the Pampean basement to the Río de La Plata craton (M2) and the later...

  8. Provenance of the late Proterozoic to early Cambrian metaclastic sediments of the Sierra de San Luis (Eastern Sierras Pampeanas) and Cordillera Oriental, Argentina

    Science.gov (United States)

    Drobe, Malte; López de Luchi, Mónica G.; Steenken, André; Frei, Robert; Naumann, Rudolf; Siegesmund, Siegfried; Wemmer, Klaus

    2009-10-01

    show one peak of detrital zircons around 550 Ma, and only a few grains are older than 700 Ma. The detrital zircon ages for the San Luis Formation show age ranges between 590 and 550 Ma. A common basin can be assumed for the Conlara Metamorphic Complex and the Puncoviscana Formation, but the available data support different sources for the rest of the Complexes of the Sierra de San Luis. These share the diminished importance or the lack of the Grenvillian detrital peak, a common feature for the late Cambrian-early Ordovician basins of the Eastern Sierras Pampeanas, in contrast to the Sierras de Córdoba, the PVF and the Conlara Metamorphic Complex.

  9. The geodynamic evolution of the eastern Sierras Pampeanas based on geochemical, Sm-Nd, Pb-Pb and SHRIMP data

    DEFF Research Database (Denmark)

    Drobe, M; Lopez de Luchi, M; Steenken, A;

    2011-01-01

    Whole-rock geochemical analyses using major and trace elements in combination with the Sm–Nd and Pb–Pb isotope systems, together with SHRIMP age dating on metasedimentary rocks from the Sierras de Chepes, the Sierras de Co´rdoba, the Sierra Norte and the San Luis Formation in the Sierra de San Luis...

  10. Primera edad U-Pb en circón usando LA-ICP-MS de un dique traquiandesítico emplazado en el granito tipo-A Los Árboles, Sierras Pampeanas Orientales First age U-Pb zircon LA-ICP-MS from trachyandesitic dyke emplaced in the A-type Los Árboles pluton, Eastern Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    Juan A Dahlquist

    2012-06-01

    Full Text Available La edad de cristalización de diques subvolcánicos emplazados en plutones graníticos carboníferos, Sierras Pampeanas Orientales, permanece incierta. La primera edad U-Pb en circón usando LA-ICP-MS obtenida en un dique que intruye al plutón Los Árboles (sierra de Fiambalá, revela una edad de cristalización de 311 ± 3 Ma.The crystallization age of subvolcanic dykes emplaced in Carboniferous granitic plutons of the Sierras Pampeanas Orientales remains uncertain. The first age precise U-Pb zircon LA-ICP-MS obtained from a dyke emplaced in the Los Árboles pluton (Sierra de Fiambalá yield a crystallization age of 311 ± 3 Ma.

  11. Volcanismo postorogénico en el extremo norte de las Sierras Pampeanas Orientales: Nuevos datos geocronológicos y sus implicancias tectónicas Postorogenic Volcanism in the Northern Boundary of the Eastern Sierras Pampeanas: Chronological Constraints and Their Tectonic Implications

    Directory of Open Access Journals (Sweden)

    PR Leal

    2003-12-01

    y 2600 Ma son más comunes. La edad modelo de 1350 Ma de la Dacita Los Burros, sugiere una corteza con más afinidades con el basamento occidental, que con el cratón del Río de La Plata. Sobre la base de estos datos una hipótesis tectónica es presentada para explicar los datos existentes.This paper presents new geochronological data on the northern sector of the eastern Sierras Pampeanas, in the province of Santiago del Estero. The regional geology of this area is mainly composed by a series of granitoids of Late Proterozoic - Early Cambrian age that are intruded by supracrustal volcanic rocks. A rhyodacitic body, unconformably emplaced in deformed granitoids, known as Los Burros Dacite is densely emplaced by small rhyolitic dykes, known as the Oncan Rhyolite and are widely exposed in the Sierra de Ambargasta. These volcanic rocks were emplaced after important deformation and exhumation of the batholith, that occurred as a result of the Pampean orogeny. Geochronological data, obtained from zircons of Los Burros Dacite by SHRIMP II, allow to determine that this body has finished its cristallization around 512 ± 3.5Ma, with a superimposed hydrothermal event of 481 ± 1.5 Ma. This last hydrothermal effect is interpreted as associated with the emplacement of the Oncán Rhyolites. Based on previous structural data, geochemical and petrological analyses, and the new dates, it is possible to interpret the existence of a magmatic arc in the eastern Sierras Pampeanas developed during Late Precambrian to Early Cambrian times, as a result of east subduction of the Pampia terrane. The collision of this terrane controlled the main deformation and metamorphism of the region at about 530 Ma, exhumation of the batholith and the emplacement in Early Cambrian times of the acidic volcanic suites here described. On the other hand, the Sm-Nd model-ages compiled for central Argentina and adjacent areas, and the new analysis here presented, show two different basements: model

  12. Holocene Paleoearthquake Clustering Along a Sierras Pampeanas (argentina) Bounding Fault?

    Science.gov (United States)

    Costa, C. H.; Ricci, W.; Owen, L. A.; Johnson, W. J.; Halperin, A.; Ahumada, E. A.

    2010-12-01

    The Sierras Pampeanas (Pampean Ranges) of Argentina are characterized by mountain blocks bounded by reverse faults, whose last stage of uplift has been attributed to the shallowing of the Nazca plate (Merlo village (32°21’30,75”S - 64°58’57,77”W ) have exposed two opposing-verging thrusts at the outcrop scale. These structures exhibit a complex interaction and propagate into the Holocene cover. The eastern branch or main fault emplaces Precambrian basement over proximal scarp-derived deposits, whereas the western thrust results in an east-directed fault-propagation fold that deforms wash-slope and fluvio-aeolian deposits. The ages of the fault-related deposits have been reasonably defined through radiocarbon and optically stimulated luminescence methods which provide ages ranging from 7.1+0.4 ka to 350+40 cal yr BP. Evidences of surface deformation are related to multiple-events with colluvial wedges and filling wedges derived from bending-moment ruptures at the fold hinge zone. It has not been possible to unravel whether these structures slipped in simultaneous or separated events which of course impacts in the discrimination of the number of earthquakes recorded in this sequence record. Accordingly, a minimum of four and a maximum of nine surface ruptures younger than 7.1+0.4 ka can be preliminarily interpreted at this trench site, where the elapsed time since the last rupture event is > 350+40 calibrated years BP. Estimated recurrence intervals vary according to different approaches from 0.8 to 3.0 ka (preferred 1.0-2.5 ka), whereas by retrodeforming the total shortening exposed in the trenches, a maximum slip rate of 1.13 mm/year was obtained. Slip rates estimated for the El Molino fault are almost one order of magnitude higher than those estimated at other master bounding faults along neighboring Pampean blocks and appear to be high for an intraplate region with much lower strain rates than the frontal deformation zone of the Andes. The data

  13. Active tectonics in the Argentine Precordillera and Western Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    L.L. Siame

    2006-12-01

    Full Text Available The Andean foreland of western Argentina (28°S-33°S corresponds to retroarc deformations associated with the ongoing flat subduction of the Nazca plate beneath the South American lithosphere. This region is characterized by high levels of seismic activity and crustal active faulting. To improve earthquake source identification and characterization in the San Juan region, data from seismology, structural geology and quantitative geomorphology were integrated and combined to provide a seismotectonic model. In this seismotectonic model, the Andean back-arc of western Argentina can be regarded as an obliquely converging foreland where Plio-Quaternary deformations are partitioned between strike-slip and thrust motions that are localized on the E-verging, thin-skinned Argentine Precordillera, and the W-verging thick-skinned Sierras Pampeanas, respectively. In this seismotectonic model, the Sierra Pie de Palo appears to be a key structure playing a major role in the partitioning of the Plio-Quaternary deformations.

  14. La estructura ándica de las Sierras Pampeanas basada en los mecanismos focales de terremotos en su región noroeste The Andean structure of the Sierras Pampeanas based on earthquake focal mechanisms in their northwestern region

    Directory of Open Access Journals (Sweden)

    Patricia Alvarado

    2010-12-01

    their focal mechanisms, depths and seismotectonic features. The magnitude Mw 5.8 earthquake on 28 May 2002, located in the eastern flank of the sierra de Velasco and the Mw 6.2 earthquake on 7 September 2004, with epicenter in the southwestern part of the sierra de Ambato, have shallow focal depths of 10 and 8 km, respectively. These results combined with the historical seismicity of the region allow us to estimate the deep structure of the Sierras Pampeanas in the study region. The seismic analyses together with interpretations of the surface structure and previous neotectonic studies ruled out extensional or strike slip deformation as the main responsible mechanism of the Present structure of this sector of the sierras de Ambato and Velasco in the northwestern Sierras Pampeanas. The comparison between the Nazca-South America plate convergence orientation as well as GPS velocities in the upper plate with the summation of the seismic moment tensor for the largest seismic energy released by crustal earthquakes of this region in the last 30 years, shows a clockwise rotation of 50º of the average P-axis orientation from the convergence orientation to the northeast suggesting important strain partition. This partition is controlled by the Eopaleozoic basement fabric, which has guided the orientation and vergence of the Andean faults.

  15. Texturas, inclusiones fluidas e isótopos estables envetas tensionales cuarzo-auríferas de cizallas paleozoicas, Sierras Pampeanas Orientales Textures,fluid inclusions and stable isotopes in quartz-auriferous tensional veins ofPaleozoic shear zones, Eastern Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    Diana Mutti

    2009-06-01

    Full Text Available En las Sierras Pampeanasafloran prominentes zonas de cizalla famatinianas con deformación dúctil adúctil frágil y edad ordovícica tardía - silúrica. Estas cizallas fueronreactivadas durante el Devónico - Carbonífero inferior por la sobreimposiciónde la orogenia achaliana, en un ambiente reológico dúctil - frágil, que en suetapa final evolucionó al campo frágil. Sincrónicamente, y con posterioridad almagmatismo devónico achaliano, se desarrollaron en las cizallas sistemas devetas tensionales, rellenas con cuarzo blanco1, blanco a gristraslúcido2, gris3 y calcedónico4, conmineralización de oro, óxidos de W - Fe - Bi y sulfuros de metales base. En lossistemas de vetas, la depositación de oro predominó en el estadio3, enel cual precipitaron también los sulfuros de metales base (In Sierras Pampeanas, conspicuous FamatinianOrdovician - Silurian shear zones crop out, with brittle to brittle - ductiledeformations. In the Devonian - lower Carboniferous, these shears werereactivated by the superimposing achalian orogeny in a brittle - ductile tobrittle regimen, transitional to brittle in the last evolution stage. Tensionalveins synchronically developed in the shear systems, after the achalianDevonian magmatism, were filled with white1, white to transparent grey2,grey3 and chalcedonic4 quartz, bearing gold, W - Fe - Bi oxidesand base metal sulphides. The deposition of gold in the quartz vein systems andthe precipitation of base metal sulphides (< 15 % per volume was the mostimportant process in stage3; these metals arranged in chains anddisseminations in the microcrystalline grey quartz. The stage3quartz appears in veinlets and bands, related to strain sites in the whitemilky and transparent grey quartz's, and determines mainly laminated, ribbonand stockwork textures. We emphasise in the grey3 quartz, throughmacro and microstructurals, termobarometric, fluid inclusions and δ18O isotopesstudies, with complementary information about

  16. High strain-rate deformation fabrics characterize a kilometers-thick Paleozoic fault zone in the Eastern Sierras Pampeanas, central Argentina

    Science.gov (United States)

    Whitmeyer, Steven J.; Simpson, Carol

    2003-06-01

    High strain rate fabrics that transgress a crustal depth range of ca. 8-22 km occur within a major Paleozoic fault zone along the western margin of the Sierras de Córdoba, central Argentina. The NNW-striking, east-dipping 'Tres Arboles' fault zone extends for at least 250 km and separates two metamorphic terranes that reached peak temperatures in the middle Cambrian and Ordovician, respectively. Exposed fault zone rocks vary from a 16-km-thickness of ultramylonite and mylonite in the southern, deepest exposures to 520 °C. Reaction-enhanced grain size reduction and grain boundary sliding were the predominant deformation mechanisms in these high strain rate rocks. Ultramylonites in the intermediate depth section also contain evidence for grain boundary sliding and diffusional mass transfer, although overprinted by late stage chlorite. In the shallowest exposed section, rocks were deformed at or near to the brittle-ductile transition to produce mylonite, cataclasite, shear bands and pseudotachylyte. The overall structure of the Tres Arboles zone is consistent with existing fault zone models and suggests that below the brittle-ductile transition, strain compatibility may be accommodated through very thick zones of high temperature ultramylonite.

  17. Late Paleozoic deformation and exhumation in the Sierras Pampeanas (Argentina): 40Ar/39Ar-feldspar dating constraints

    Science.gov (United States)

    Löbens, Stefan; Oriolo, Sebastián; Benowitz, Jeff; Wemmer, Klaus; Layer, Paul; Siegesmund, Siegfried

    2016-09-01

    Systematic 40Ar/39Ar feldspar data obtained from the Sierras Pampeanas are presented, filling the gap between available high- (>~300 °C) and low-temperature (Pie de Palo regions, whereas the Sierras de San Luis and the Sierra de Comechingones regions record exhumation during the Carboniferous. Comparison between new and available data points to a Carboniferous tectonic event in the Sierras Pampeanas, which represents a key period to constrain the early evolution of the proto-Andean margin of Gondwana. This event was probably transtensional and played a major role during the evolution of the Paganzo Basin as well as during the emplacement of alkaline magmatism in the retroarc.

  18. Anfibios de las Sierras Pampeanas Centrales de Argentina: diversidad y distribución altitudinal

    Directory of Open Access Journals (Sweden)

    Julián N. Lescano

    2015-09-01

    Full Text Available Amphibians from Sierras Pampeanas Centrales of Argentina: diversity and altitudinal distribution. Sierras Pampeanas Centrales (SPC mountains are located in Córdoba and San Luis provinces (Argentina and represent an area of unique biogeographic importance. In this paper we provide a synthesis about the knowledge of diversity and altitudinal distribution of anurans that inhabit SPC mountains. We compiled a species list through different information sources (field data, biological collections and bibliography. Using this information we characterize altitudinal distribution range of each species and analyze associations between species richness and composition and altitude gradient. We recorded 24 amphibians species belonging to five families. These species are heterogeneously distributed over the altitude gradient of SPC. We detect a linear negative relationship between altitude and species richness and defined assemblages associated with different altitude sectors. The results obtained in the paper represent basic information that will be useful to evaluate anthropogenic impact on this particular and fragile mountain system.

  19. Late Paleozoic deformation and exhumation in the Sierras Pampeanas (Argentina): 40Ar/39Ar-feldspar dating constraints

    Science.gov (United States)

    Löbens, Stefan; Oriolo, Sebastián; Benowitz, Jeff; Wemmer, Klaus; Layer, Paul; Siegesmund, Siegfried

    2017-09-01

    Systematic 40Ar/39Ar feldspar data obtained from the Sierras Pampeanas are presented, filling the gap between available high- (> 300 °C) and low-temperature (< 150 °C) thermochronological data. Results show Silurian-Devonian exhumation related to the late stages of the Famatinian/Ocloyic Orogeny for the Sierra de Pocho and the Sierra de Pie de Palo regions, whereas the Sierras de San Luis and the Sierra de Comechingones regions record exhumation during the Carboniferous. Comparison between new and available data points to a Carboniferous tectonic event in the Sierras Pampeanas, which represents a key period to constrain the early evolution of the proto-Andean margin of Gondwana. This event was probably transtensional and played a major role during the evolution of the Paganzo Basin as well as during the emplacement of alkaline magmatism in the retroarc.

  20. Nuevas evidencias de deformaciones cuaternarias asociadas a la falla Sierra chica, Sierras pampeanas de Córdoba

    Directory of Open Access Journals (Sweden)

    Guillermo L Sagripanti

    2012-12-01

    Full Text Available En la intraplaca argentina, entre los 31º 45' y 32º 45' de latitud S, en el frente occidental de la Sierra Chica, Sierras Pampeanas de Córdoba, la presencia de morfologías superficiales y deformaciones en sedimentos cuaternarios permiten deducir que la actividad tectónica neógena en la región, tuvo continuidad en el Holoceno y probablemente ha tenido asociada la ocurrencia de paleoterremotos. Los objetivos de la presente contribución son presentar nuevas evidencias de deformaciones cuaternarias asociadas a la falla Sierra Chica, extender su traza hacia el sur en la llanura y hacer una estimación preliminar del potencial sismogénico asociado a esta estructura. Se relevaron siete perfiles transversales a la traza de una falla secundaria del frente principal de levantamiento de la Sierra Chica. Estos presentan el basamento cristalino precámbrico, depósitos conglomerádicos y sedimentos no cohesivos cuaternarios, afectados por deformaciones dúctiles y frágiles correspondientes a reactivaciones pleistocenas y holocenas de la estructura. Los resultados obtenidos han permitido extender la traza de la falla hacia el S en la llanura hasta el arroyo Tegua, relevar estructuras deformacionales en sedimentos finos no reportadas hasta el presente y estimar la magnitud máxima de un terremoto futuro, entre Ms 6,7-7,5 y Mw=7,5, asociado a la falla Sierra Chica.

  1. La actividad neotectónica en la sierra Baja de San Marcos - Cruz del Eje, flanco occidental de las Sierras Pampeanas Orientales

    OpenAIRE

    A Massabie; A. Sanguinetti; G Lo Forte; M Cegarra

    2003-01-01

    El área pedemontana de San Marcos Sierra-Cruz del Eje constituye, en la provincia de Córdoba, Argentina, una comarca clave para el análisis neotectónico en las Sierras Pampeanas Orientales. En esta región se han realizado estudios centrados en la unidad morfoestructural sierra Baja de San Marcos donde, aplicando un control múltiple de datos estructurales, geomorfológicos, sedimentológicos, paleontológicos y radimétricos, se ha determinado temporal y espacialmente la evolución de la actividad ...

  2. Actualización en el límite entre sierras Pampeanas occidentales y Precordillera Oriental, en la provincia de San Juan Updating the boundary between the western Pampean ranges and the eastern Precordillera, province of San Juan

    Directory of Open Access Journals (Sweden)

    Juvenal J. Zambrano

    2008-03-01

    Full Text Available En este trabajo se analiza el sistema de fallamiento existente en la depresión tectónica de Tulum, ubicada en la parte este y sur de la provincia de San Juan, en el oeste árido de Argentina. El límite entre los dos sistemas morfoestructurales, uno la Precordillera Oriental y el otro el Sistema Pampeano Occidental ha sido establecido en trabajos anteriores, a lo largo del sistema de fallamiento de Tulum, que cruza a la depresión diagonalmente en dirección NNE. No obstante la disponibilidad de nueva información de sondeos eléctricos verticales y de algunas perforaciones para búsqueda de agua subterránea, efectuados al sur y al oeste del cerro Valdivia, permite señalar que hacia el suroeste de este núcleo de basamento metamórfico limitado en ambos flancos por fallas, el límite Sistema Pampeano y Precordillera se aproxima al cordón montañoso de sierra Chica de Zonda, continuando al sur en el cerro Salinas. De allí al SSO existen, en superficie, indicaciones de que el sistema de fallamiento continúa hasta el Montecito, donde el sistema pampeano de fallas queda interrumpido por la gran falla con actividad cuaternaria que sirve de límite oriental a la sierra de Las Peñas. El contacto entre ambos sistemas forma el extremo sur de la Precordillera Oriental en subsuelo. Este conocimiento estructural permite no solo ser aplicado a la prospección de agua sino también a la de hidrocarburos en la región.An analysis is made of the fault system in the Tulum tectonic depression, situated in the southeastern part of the province of San Juan, which is in the arid western part of Argentina. The boundary of two morphostructural systems occurs in this valley: the eastern Andean Precordillera and the western Pampean ranges. In former studies it was found that this boundary runs along a fault system that crosses the Tulum depression with a NNE trends. The availability of new information from electric resistivity tests and wells drilled for ground

  3. A transient fault-valve mechanism operating in upper crustal level, Sierras Pampeanas, Argentina

    Science.gov (United States)

    Japas, María Silvia; Urbina, Nilda Esther; Sruoga, Patricia; Garro, José Matías; Ibañes, Oscar

    2016-11-01

    Located in the Sierras Pampeanas (the broken-foreland of the Pampean flat slab segment in the southern Central Andes), the Cerro Tiporco volcanic field shows Neogene hydrothermal activity linked to migration of arc-magmatism into the foreland. Late Neogene deposits comprise epithermal vein systems emplaced in Precambrian-Early Palaeozoic igneous-metamorphic basement, Late Miocene sedimentary rocks and Early Pliocene volcaniclastic rocks. Mineralization consists of calcareous onyx, aragonite and calcite veins as well as travertine deposits. Onyx and aragonite occur as fill of low-displacement nearly vertical reverse-sinistral faults striking NW, and nearly horizontal dilatant fractures. The latter consist of load-removal induced fractures affecting the igneous-metamorphic rocks, as well as bedding planes in the Late Miocene sediments. The presence of veins recording multiple fracture episodes and crack-and-seal growth of veins suggests relatively low differential stress and supralithostatic fluid pressure, as well as cyclic changes in pore pressure and high mineral-deposition/fracture-opening ratio. These conditions support a mechanism of fault-valve behaviour during onyx and aragonite vein emplacement. The fault-valve mechanism involves fractures associated with impermeable barriers between environments with different fluid pressure. Faulting generated an appreciable directional permeability triggering fluid migration from the highest to the lowest pressure region, with subsequent deposition and sealing that started a new pressurization-faulting-sealing cycle. Late aragonite and calcite veins suggest a change in kinematics indicating the onset of tectonic-load conditions.

  4. La actividad neotectónica en la sierra Baja de San Marcos - Cruz del Eje, flanco occidental de las Sierras Pampeanas Orientales Neotectonic activity in the Sierra Baja de San Marcos-Cruz del Eje area, west flank of Sierras Pampeanas Orientales

    OpenAIRE

    A Massabie; A. Sanguinetti; G Lo Forte; M Cegarra

    2003-01-01

    El área pedemontana de San Marcos Sierra-Cruz del Eje constituye, en la provincia de Córdoba, Argentina, una comarca clave para el análisis neotectónico en las Sierras Pampeanas Orientales. En esta región se han realizado estudios centrados en la unidad morfoestructural sierra Baja de San Marcos donde, aplicando un control múltiple de datos estructurales, geomorfológicos, sedimentológicos, paleontológicos y radimétricos, se ha determinado temporal y espacialmente la evolución de la actividad ...

  5. Along-Strike Variations in Focal Mechanisms of Central Andean Crustal Earthquakes: Northern Peru through the Argentina Sierras Pampeanas

    Science.gov (United States)

    Devlin, S.; Isacks, B. L.

    2003-12-01

    120 shallow focal mechanisms in the crust above the subducted Nazca plate were assembled from the Harvard CMT catalog and published studies covering over 40 years of seismicity. The study area included the Andes crust above three major segments of the subducted plate, the Peruvian and Argentinean flat-slab segments and the intervening segment where the subducted Nazca plate dips more steeply. The most seismically active regions continue to be the thick-skinned foreland thrust belts in the eastern Andes of Peru and the Sierras Pampeanas. The earthquakes there are clearly associated with youthful tectonic structures with strong topographic signatures as revealed by the new 90 m SRTM digital elevation models. The mechanisms are dominantly of the thrust type but include a minority of strike-slip orientations. However the P axes remain consistent. The thin-skinned thrust belts east of the central Andean Plateau show significant activity only near Santa Cruz, Bolivia and northern Argentina; most of the Sub-Andean thrust belt of Bolivia and southern Peru remains aseismic. The central Andean plateau itself also remains aseismic except for the region of southern Peru and two earthquakes in the Puna. The crustal seismicity in southern Peru is largely concentrated on the western side of the plateau. The focal mechanisms show a strong grouping of T axes in a horizontal, north-south orientation. Both normal and strike-slip mechanisms occur in this region, with no obvious correlation with elevation or surface structures. Remarkably, with the exception of one normal fault type mechanism near the Cusco basin, the earthquakes occur in regions of the western parts of the Altiplano that do not exhibit topographic evidence of substantial crustal deformation. These results are consistent with a model in which the Altiplano of southern Peru, with a trend most oblique to the overall direction of convergence, manifests a left-lateral shearing component across the orogen.

  6. Deformación cuaternaria asociada al frente de levantamiento oriental de las sierras de Velasco y Ambato, Sierras Pampeanas occidentales

    Directory of Open Access Journals (Sweden)

    Analía L. Casa

    2010-12-01

    Full Text Available Sobre el frente oriental de la sierra de Velasco y extremo sur de la sierra de Ambato, Sierras Pampeanas Occidentales, se han hallado nuevas evidencias de actividad tectónica cuaternaria en cercanías de la ciudad de La Rioja. Los rasgos reconocidos corresponden a distintos tramos reactivados de las fallas que delimitan los frentes serranos y a estructuras que afectan los depósitos cuaternarios sobre el piedemonte. la sierra de Velasco Oriental se encuentra marginada por fallas de rumbo NNE e inclinación al ONO, mientras que la sierra de Ambato austral presenta estructuras de rumbo NE que inclinan al NO. En el bloque Carrizal estas direcciones se interfieren originando un sector de mayor complejidad estructural. La deformación observada evidencia la persistencia de un régimen compresivo durante el Cuaternario al que se asocian fallas inversas de vergencia oriental a sudoriental. Estas fallas continúan elevando los cordones serranos y constituyen potenciales fuentes sismogénicas.

  7. Estratigrafía de la cuenca de vinchina (terciario, sierras pampeanas, provincia de la Rioja

    Directory of Open Access Journals (Sweden)

    Patricia L Cioccili

    2010-03-01

    Full Text Available La cuenca de Vinchina, en el noroeste de la provincia de La Rioja, conforma uno de los depocentros cenozoicos del antepaís fracturado (broken foreland en el segmento de Sierras Pampeanas-Famatina-Precordillera-Cordillera Frontal de los Andes. Las fases iniciales del relleno de la cuenca están representadas por delgados depósitos de sistemas fluviales y lacustres efímeros asignados a la Formación Puesto La Flecha (Paleoceno-Eoceno Temprano, la cual es cubierta en forma neta por sedimentitas eólicas de la Formación Vallecito (Eoceno. Por encima, mediante una leve discordancia erosiva, se encuentra la Formación Vinchina (Oligoceno-Mioceno Temprano? dominada por secuencias generadas en sistemas fluviales areno-pelíticos y arenoconglomerádicos depositados bajo condiciones de clima semiárido. Dentro de esta unidad se ha diferenciado el miembro inferior, dominado por depósitos areno-pelíticos, y el superior que cubre al anterior mediante una superficie erosiva de bajo ángulo tapizada por niveles de ortoconglomerados polimícticos (discordancias progresivas. La Formación Toro Negro (Mioceno-Plioceno Temprano cubre mediante una discordancia erosiva a la Formación Vinchina. El miembro inferior de la Formación Toro Negro está dominado por depósitos areno-pelíticos sedimentados en sistemas fluviales anastomosados con baja proporción de conglomerados. Por su parte, el miembro superior, que cubre mediante una leve discordancia erosiva a la unidad infrayacente, está constituido por depósitos conglomerádicos correspondientes a sistemas fluviales entrelazados y a bajadas dominadas por flujos canalizados. Finalmente, se encuentran los depósitos de abanicos aluviales de la Formación El Corral (Plioceno. Este nuevo cuadro estratigráfico para la cuenca de Vinchina permite establecer la conexión en su estadio inicial con la cuenca de La Troya, para luego evolucionar en forma independiente (antepaís fracturado.

  8. Los diques comendíticos de Papachacra (Catamarca: magmatismo peralcalino en sierras Pampeanas orientales

    Directory of Open Access Journals (Sweden)

    Fernando Colombo

    2010-03-01

    Full Text Available En Papachacra (Provincia de Catamarca, NO de Argentina hay un plutón compuesto por varios tipos diferentes de granitoides de tipo A con afinidad alcalina. Las rocas más tardías son riolitas peralcalinas (comenditas, que forman diques de hasta 50 cm atravesando el granito biotítico El Portezuelo, el cual está genéticamente desvinculado. Tienen textura porfírica y están compuestas por fenocristales de feldespato potásico (Or97-98 Ab2-3 y egirina (Ac94-98 en una mesostasis afanítica de cuarzo, feldespato potásico, albita, egirina y anfíbol litífero relacionado a la flúor-ferro-leakeíta. Los minerales accesorios son ilmenita, magnetita, óxidos del grupo del pirocloro, epidoto rico en tierras raras, zircón intersticial, monacita- (Ce y un óxido de Nb-Y-Fe no identificado. El contenido de SiO2 varía entre 68,28 y 69,33%, con muy bajo Mg, Ca, Ba, Sr y Eu, y altas concentraciones de Nb (399-409 ppm, Ta (16-34 ppm, Th (46-84 ppm, Y (101-192 ppm, Zn (280-320 ppm, Ga (42-47 ppm y especialmente Zr (2324-3000 ppm. Las comenditas se intruyeron durante un evento magmático anorogénico. Un estudio isotópico (Rb-Sr de reconocimiento hecho a rocas relacionadas indica una edad de 295 + 8 Ma, con una relación 87Sr/86Sr inicial cercana a 0,7041, lo que apunta a una fuente del manto sublitosférico o la base de la corteza inferior. Estas rocas pertenecen a la clase A1 de granitos de tipo A, sugiriendo un origen relacionado a rifting o a puntos calientes, y sus relaciones de elementos trazas muestran afinidades con fundidos relacionados a basaltos de islas oceánicas. En este sentido son diferentes de todos los granitos de tipo A post-devónicos descriptos en Sierras Pampeanas Orientales.

  9. Las superficies de erosión en las Sierras Pampeanas de Córdoba: algunas consideraciones sobre su génesis

    Directory of Open Access Journals (Sweden)

    C.A. Beltramone

    2007-09-01

    Full Text Available Las Sierras Pampeanas de Córdoba constituyen parte de la unidad morfoestructural Sierras Pampeanas Orientales. Se considera la existencia de una sola superficie de erosión, preservada en diferentes posiciones topográficas. Escarpas de fallas limitan las superficies de erosión reconocidas. No fueron reconocidos signos que evidencien el proceso de pedimentación en su base, ni profundos perfiles de meteorización (saprolito. Se consideran a esta superficie como una peneplanicie formada durante el Paleozoico y posteriormente desmembrada por los movimientos tectónicos que dieron lugar a la formación de las sierras de Córdoba.

  10. La actividad neotectónica en la sierra Baja de San Marcos - Cruz del Eje, flanco occidental de las Sierras Pampeanas Orientales Neotectonic activity in the Sierra Baja de San Marcos-Cruz del Eje area, west flank of Sierras Pampeanas Orientales

    Directory of Open Access Journals (Sweden)

    A Massabie

    2003-12-01

    Full Text Available El área pedemontana de San Marcos Sierra-Cruz del Eje constituye, en la provincia de Córdoba, Argentina, una comarca clave para el análisis neotectónico en las Sierras Pampeanas Orientales. En esta región se han realizado estudios centrados en la unidad morfoestructural sierra Baja de San Marcos donde, aplicando un control múltiple de datos estructurales, geomorfológicos, sedimentológicos, paleontológicos y radimétricos, se ha determinado temporal y espacialmente la evolución de la actividad neotectónica del fallamiento andino. Se presentan evidencias sobre la reactivación cuaternaria tardía de la Falla Sierra Baja de San Marcos, conspicua falla inversa de vergencia occidental con componentes de desplazamiento de rumbo y de inclinación, enlazando los episodios tectónicos con las modificaciones del paisaje. Estas modificaciones son expresadas por los depósitos de endicamiento del río Quilpo, por los niveles aterrazados, vinculados a los cauces actuales de los ríos de la Costa (San Marcos y Quilpo, y por los cambios en su desarrollo de la red de avenamiento principal de la región. La edad 14C corregida de 2.560±120 aap, obtenida para los sedimentos del endicamiento permite acotar un primer episodio de actividad, Holoceno tardío, de la Falla Sierra Baja de San Marcos. Las observaciones efectuadas sobre la misma estructura, en una trinchera excavada para su investigación, confirman su extensión hacia el noroeste, dan evidencias sobre una segunda etapa de movimientos en el Holoceno tardío y determinan sus características estructurales comunes a otras fallas con actividad neotectónica estudiadas en las Sierras Pampeanas Orientales, las cuales responden a una mecánica transpresiva.The San Marcos Sierra-Cruz del Eje mountain-piedmont (Córdoba province, Argentina is a key area in order to analyse the neotectonic behaviour of the Sierras Pampeanas Orientales. In this place, the evolution of recent Andean faulting activity has

  11. Nuevas edades radimétricas para la Formación Toro Negro en la Sierra de los Colorados, Sierras Pampeanas Noroccidentales, provincia de La Rioja New radiometric ages for the Toro Negro Fromation in the Sierra de los Colorados, northwestern Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    P.L. Ciccioli

    2005-03-01

    Full Text Available En este trabajo se dan a conocer nuevas edades radimétricas obtenidas por el método K/Ar roca total sobre dos niveles de tobas vítreas de la parte media-superior de la Formación Toro Negro en la sierra de los Colorados, Sierras Pampeanas Noroccidentales (provincia de La Rioja. Las edades 8,6 ± 0,3 Ma y 6,8 ± 0,2 Ma ubican a la Formación Toro Negro en el Mioceno superior modificando así la edad pliocena establecida anteriormente. Los valores obtenidos presentan un alto grado de confiabilidad, dado que se tratan de tobas vítreas las cuales no tienen ningún signo de retransporte, contaminación ni alteración diagenética. Los niveles de tobas han sido mapeados y georeferenciados con coordenadas obtenidas con GPS. Las muestras presentan una precisa ubicación en la columna estratigráfica y se encuentran lo suficientemente próximas de manera de controlar indirectamente los valores obtenidos.New absolute ages derived from whole rock K/Ar dating of two vitric tuffs collected from the upper-middle part of the Toro Negro Formation in the outcrops of the Sierra de Los Colorados, Sierras Pampeanas Noroccidentales (La Rioja Province are presented herein. The obtained values of 8,6 ± 0,3 Ma and 6,8 ± 0,2 Ma respectively, indicate an Upper Miocene age and challenge the previous Pliocene age proposed for this unit. The results presented here have a high degree of confidence because they do not show evidences of reworking, mixing with terrigenous clastics nor diagenetic alteration. The tuff levels were mapped and georeferenced using GPS coordinates and their close location in the stratigraphic column provides an additional control for the obtained ages.

  12. Análisis geoquímico-geocronológico de rocas granulíticas y calcosilicáticas de las Sierras Pampeanas Noroccidentales Geochemical and geochronological analyses of granulitic and calc-silicate rocks of northwestern Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    AJ Toselli

    2003-12-01

    Full Text Available Las rocas calcosilicáticas y granulíticas, muestran tipologías diferentes en los sectores occidental y oriental de las Sierras Pampeanas Noroccidentales. Las asociaciones minerales difieren según el grado metamórfico y las composiciones químicas varían desde ricas en óxido de calcio a ricas en sílice; siendo diferentes de las anfibolitas. Las rocas calcosilicáticas en las Cumbres Calchaquíes, Aconquija y Ancasti muestran paragénesis con cuarzo, plagioclasa, clinozoicita, granate, hornblenda, titanita, diópsido, biotita y calcita; mientras que en la sierra de Quilmes, en facies granulita, se presenta hipersteno y escasa biotita. Ambas son diferentes de las rocas calcosilicáticas de la sierra de Fiambalá. Los datos geocronológicos obtenidos, permiten correlacionar al evento de muy bajo-bajo grado metamórfico de la Formación Puncoviscana, con edades de 530-568 Ma, con sus equivalentes más profundos en la sierra de Quilmes, representados por rocas calcosilicáticas de 571 Ma, granulitas con 480 Ma y las relacionadas con fenómenos anatécticos y graníticos con edades de 453 Ma (Granito Cafayate y 446 Ma (Loma Colorada, típicas para el Ciclo Famatiniano. Esto se reitera en la tonalita El Infiernillo, de 419 Ma, en las granodioritas sintectónicas de la Formación El Portezuelo, con 445 Ma; en el gneis de La Puntilla de Copacabana con 483 Ma y en el gneis de la sierra de Fiambalá con 440 Ma. Asimismo la faja de deformación de la sierra de Copacabana, con una edad de 388 Ma, se relaciona con los granitos de Zapata de 395 Ma, y los de La Punta, de 405 Ma y Señor de la Peña, 376 Ma, en la sierra de Velasco. Esto muestra que metamorfismo, deformación y magmatismo del Ciclo Famatiniano, se sobreimponen al Ciclo Pampeano.The calcsilicate and granulites, show different tipology depending on they belong to the western or eastern belts of the northwestern Sierras Pampeanas. The mineral associations vary according to the metamorphic

  13. Control estructural de las mineralizaciones de fluorita del batolito Cerro Áspero, Sierras Pampeanas de Córdoba Structural control of vein-type fluorite deposits of Cerro Áspero batholith, Sierras Pampeanas of Córdoba

    Directory of Open Access Journals (Sweden)

    Jorge E Coniglio

    2010-12-01

    Full Text Available Con más de 1.000.000 t de reservas totales el batolito Cerro Áspero, magmatismo devónico de alto potasio, es portador de las mayores concentraciones de fluorita de las Sierras Pampeanas. Las vetas epitermales son de edad cretácica, subverticales, poseen potencias generalmente menores a 3 m y se extienden a profundidades mayores a 200 metros. Ocurren en un área de 440 km² con una distribución intrabatolítica predominante. La geometría y la cinemática de las estructuras mineralizadas son consistentes con deformación por cizalla simple, dextrógira, con el eje extensional principal (σ3 orientado hacia el NNO. Esta situación implantó en el área estructuras extensionales N70ºE ( 4 km de corrida, que presentan patrones de fallas transcurrentes, con bifurcaciones, deflexiones, aperturas, saltos, cierres y fracturas en échelon asociadas. Los estudios texturales y estructurales en las vetas han permitido distinguir cuatro estadios sucesivos de mineralización que fueron controlados por una actividad discontinua de la cupla dextral. Este modelo estructural es similar a aquéllos propuestos para mineralizaciones de fluorita emplazadas en otros sectores del continente durante el mismo período, los que vinculan el control tectónico con la apertura del océano Atlántico sur. El registro del relleno hidrotermal permitió reconstruir la historia de apertura de las estructuras y puede usarse como un criterio efectivo de prospección y exploración. Las mayores concentraciones de mineral ocurren en las estructuras extensionales y en las flexiones dilatantes de las estructuras asociadas con la zona de cizallamiento principal NNE-SSO, que registran la secuencia mineralizada completa.With over 1,000,000 t of total reserves, the high-K devonian granites of the Cerro Áspero batholith (440 km² are the most important fluorite-bearing granitic suite in the Sierras Pampeanas. The epithermal fluorite veins, of Cretaceous age, fill in steeply dipping

  14. Los granitos peraluminosos de las Sierras de Vinquis, Cerro Negro y Zapata (Sierras Pampeanas, provincia de Catamarca, Argentina

    Directory of Open Access Journals (Sweden)

    Medina, M. E.

    1992-12-01

    Full Text Available The studied plutons are close to several batholiths of this region, as Sierra de Mazán and other, but with some mineralogical peculiarities. The magmatic cordierite, common in proximate places, is scarce, as sillimanite, while the andalusite is very rare, with few tourmaline. Fluorite and allanite are also typical accasories only in the granites of the Sierra de Zapata. All plutons are peraluminous of potassic tendency, with cortical affinity.The interpretation of the geochemical values distinguishes between granites of different maturity, emplaced under a predominant influence of active margin for Cerro Negro and Vinquis, while the batholith of Zapata has, below these concepts, a marked feature of within plate.The mineralogical associations suggest that the granites of Cerro Negro and Vinquis were emplaced to pressures of 2 kb or less and temperature of 650º C, while the granites of Zapata had done under conditions of lesser pressure, between 1.5 and 2.0 kb and lower temperature, 600-650º C.A grandes rasgos, los plutones estudiados tienen semejanzas con otros del entorno regional, tal como los de la Sierra de Mazán, pero con peculiaridades mineralógicas. La cordierita magmática, que en lugares próximos es muy abundante, es aquí escasa, al igual que la sillimanita, mientras que la andalucita es muy rara y la turmalina poco frecuente. La fluorita y allanita son accesorios comunes y de cierta abundancia sólo en los granitos de la Sierra de Zapata.Todos los plutones son peralumínicos y de tendencia potásica, con neta afinidad cortical. El estudio estadístico de datos geoquímicos seleccionados, permite diferenciar agrupaciones que tienen un reflejo satisfactorio en los plutones caracterizados, por encima de las variaciones de facies. La interpretación de los valores geoquímicos distingue granitos de desigual madurez, emplazados bajo una influencia predominante de margen activo o intraplaca de características continentales, en

  15. Control estructural de las mineralizaciones de fluorita del batolito Cerro Áspero, Sierras Pampeanas de Córdoba

    Directory of Open Access Journals (Sweden)

    Jorge E Coniglio

    2010-12-01

    Full Text Available Con más de 1.000.000 t de reservas totales el batolito Cerro Áspero, magmatismo devónico de alto potasio, es portador de las mayores concentraciones de fluorita de las Sierras Pampeanas. Las vetas epitermales son de edad cretácica, subverticales, poseen potencias generalmente menores a 3 m y se extienden a profundidades mayores a 200 metros. Ocurren en un área de 440 km² con una distribución intrabatolítica predominante. La geometría y la cinemática de las estructuras mineralizadas son consistentes con deformación por cizalla simple, dextrógira, con el eje extensional principal (σ3 orientado hacia el NNO. Esta situación implantó en el área estructuras extensionales N70ºE ( 4 km de corrida, que presentan patrones de fallas transcurrentes, con bifurcaciones, deflexiones, aperturas, saltos, cierres y fracturas en échelon asociadas. Los estudios texturales y estructurales en las vetas han permitido distinguir cuatro estadios sucesivos de mineralización que fueron controlados por una actividad discontinua de la cupla dextral. Este modelo estructural es similar a aquéllos propuestos para mineralizaciones de fluorita emplazadas en otros sectores del continente durante el mismo período, los que vinculan el control tectónico con la apertura del océano Atlántico sur. El registro del relleno hidrotermal permitió reconstruir la historia de apertura de las estructuras y puede usarse como un criterio efectivo de prospección y exploración. Las mayores concentraciones de mineral ocurren en las estructuras extensionales y en las flexiones dilatantes de las estructuras asociadas con la zona de cizallamiento principal NNE-SSO, que registran la secuencia mineralizada completa.

  16. Primera edad U-Pb en circón usando LA-ICP-MS de un dique traquiandesítico emplazado en el granito tipo-A Los Árboles, Sierras Pampeanas Orientales

    Directory of Open Access Journals (Sweden)

    Juan A Dahlquist

    2012-06-01

    Full Text Available La edad de cristalización de diques subvolcánicos emplazados en plutones graníticos carboníferos, Sierras Pampeanas Orientales, permanece incierta. La primera edad U-Pb en circón usando LA-ICP-MS obtenida en un dique que intruye al plutón Los Árboles (sierra de Fiambalá, revela una edad de cristalización de 311 ± 3 Ma.

  17. Relaciones isotópicas Sm/Nd en rocas graníticas y miloníticas de Sierras Pampeanas del noroeste Argentino

    Directory of Open Access Journals (Sweden)

    Kawashita, K.

    2005-04-01

    Full Text Available The Velasco, Copacabana and Paimán Ranges in Sierras Pampeanas, are constituted mainly by paleozoic plutonic bodies of the Famatinian cycle (Huaco, Antinaco and Paimán and for mylonitic rocks (TIPA Shear Zone, originated as a consequence of dynamic events happening during the Upper Ordovician-Devonian. The last magmatic event of the area would probably have of devonian age (Granite San Blas. Model-ages of two stages were calculated based on 147Sm/144Nd relationships; the obtained values are closely grouped at around 1594 Ma. and the more plausible interpretation seems to be a reworking of an Early Proterozoic protolith.Las sierras de Velasco, Copacabana y Paimán, en el ambiente de Sierras Pampeanas, están constituidas principalmente por cuerpos plutónicos del Paleozoico inferior, relacionados con el ciclo Famatiniano (Granitos Huaco, Antinaco y Paimán y por rocas miloníticas (Faja Milonítica TiPA, originadas a partir de estos protolitos como consecuencia de eventos dinámicos acaecidos durante el Ordovícico superior-Devónico. El último evento magmático del área es de edad probablemente devónica (Granito San Blas. Se calcularon edades modelos de «dos estadios» en base a relaciones 147Sm/144Nd; los valores obtenidos se presentan estrechamente agrupadas en torno a 1594 Ma. y se interpretan a este basamento como un protolito del Proterozoico medio retrabajado.

  18. Faja de Deformación La Horqueta, sierra de Velasco, Sierras Pampeanas, NO de Argentina: petrografía, geoquímica, estructuras y significado tectónico

    Directory of Open Access Journals (Sweden)

    Toselli, A. J.

    2007-12-01

    Full Text Available The La Horqueta Shear Zone (LHSZ is the sixth shear zone recognized in the Sierra de Velasco, Sierras Pampeanas, NW Argentina. This shear zone separates two types of metagranitoids of contrasting petrographical and geochemical characteristics: metagranodiorites, outcropping towards the SW, consist in weakly peraluminous biotite-allanite-titanite granodiorites similar to the I-type granitoids of southern Sierra de Velasco and of neighboring ranges that are part of the Famatinian magmatic arc, while metagranites, outcropping towards the NE, consist in strongly peraluminous biotite-muscovite monzogranites identical to the Antinaco Orthogneis of northern Sierra de Velasco, which is part of an inner S-type granitoid belt. The LHSZ, developed from these two protoliths, has a thickness of 1 to 2 km and is composed of protomylonites and mylonites with strong NNW trending and E dipping mylonitic foliation. Cinematic analyses indicates a main transpressive deformational regime with an inverse-sinistral component, accompanied by a subordinate dextral transcurrent component, which possibly placed the two tectonic settings in contact.La Faja de Deformación La Horqueta (FDLH es la sexta faja de cizalla reconocida en la sierra de Velasco, Sierras Pampeanas, NO de Argentina. Esta faja separa dos tipos de metagranitoides de características petrográficas y geoquímicas contrastadas: metagranodioritas, hacia el SO, consisten en granodioritas con biotita-allanita-titanita débilmente peraluminosas que se asemejan a los granitoides tipo I del sur de la sierra de Velasco y de sierras aledañas pertenecientes al arco magmático famatiniano, mientras que los metagranitos, hacia el NE, consisten en monzogranitos con biotita-muscovita fuertemente peraluminosos idénticos al Ortogneis Antinaco del norte de la sierra de Velasco, el cual pertenece a un cinturón de granitoides tipo S interno, respecto del arco famatiniano. La FDLH, desarrollada allí a partir de estos

  19. La estructura ándica de las Sierras Pampeanas basada en los mecanismos focales de terremotos en su región noroeste

    Directory of Open Access Journals (Sweden)

    Patricia Alvarado

    2010-12-01

    Full Text Available El modelado de formas de ondas sísmicas de banda ancha de redes globales y de Chile para dos terremotos corticales moderados de la región noroeste de las Sierras Pampeanas ha permitido caracterizar sus mecanismos focales, profundidades hipocentrales y características sismotectónicas. El terremoto de magnitud Mw 5.8 del 28 de mayo de 2002 localizado en el flanco oriental de la sierra de Velasco y el terremoto Mw 6.2 del 7 de setiembre de 2004 con epicentro en la parte sudoccidental de la sierra de Ambato muestran profundidades focales someras de 10 y 8 km, respectivamente. Estos resultados combinados con la sismicidad histórica de la región permiten esbozar la estructura profunda de las Sierras Pampeanas en la región estudiada. El análisis sismológico efectuado en forma conjunta con la interpretación de la estructura superficial y los estudios neotectónicos previos permiten descartar mecanismos extensionales o de deformación mediante desplazamiento de rumbo como los responsables de la estructuración actual de las sierras de Ambato y Velasco. Se realiza la comparación entre el vector de velocidad de convergencia entre las placas de Nazca y Sudamericana, y los vectores relativos de velocidades de GPS en la región de estudio con la sumatoria del tensor momento sísmico para la mayor liberación de energía sísmica de sismos corticales ocurridos en la región en los últimos 30 años. Esta comparación predice una rotación horaria de 50º del eje de máxima compresión (eje P promedio respecto de la orientación hacia el noreste de la convergencia mencionada y muestra una importante partición de la deformación. Se interpreta que esta partición está controlada por la fábrica eopaleozoica del basamento, que ha regulado la orientación y vergencia de las fallas andinas.

  20. Pinturas rupestres y estructuras de piedra en las Sierras de Curicó (extremo noroccidental de Tandilia, Región Pampeana

    Directory of Open Access Journals (Sweden)

    Patricia Madrid

    2000-12-01

    Full Text Available En las Sierras de Curicó (también conocidas como de La China en el Pdo. de Olavarría, se han detectado pinturas rupestres en paredones y reparos de los afloramientos tabulares de cuarcita. Se trata de tres sectores con motivos lineales, geométricos, pintados en rojo. En el faldeo de la misma sierra, se localizaron dos estructuras pequeñas de piedra pircada de forma circular. En la cima de otro afloramiento rocoso, ubicado 500 m al oeste de estas estructuras, se halló una acumulación oval de piedras. En este trabajo se resumen las características del conjunto arqueológico y se presentan los resultados de los sondeos realizados en una de esas estructuras. Se examina la contemporaneidad entre las estructuras y las pinturas rupestres y su posible filiación tehuelche. Se comparan estas pinturas con otras manifestaciones similares de la Región Pampeana. Por último, se exploran aspectos simbólicos y religiosos de las sociedades pampeanas tardías.In the Curicó hills (also known as the La China hill, in the Olavarría district, rock art has been discovered on walls and in shelters in the quartzite tabular outcrops of the Balcarce Formation. The paintings are in three sectors and consist of lineal and geometrical motifs painted in red. On the slope of the hill, two stone circular structures were detected, and on the top of the opposite hill an oval stone structure was also found. In this article, the characteristics of this archaeological material are summarised and the results from test pits, excavated in one of these structures is presented. The contemporaneity among the findings is examined as well as its possible tehuelche affiliation. Finally, the symbolic and religion dimensions of the Late Pampean indigenous societies are explored.

  1. Análisis geoquímico-geocronológico de rocas granulíticas y calcosilicáticas de las Sierras Pampeanas Noroccidentales

    Directory of Open Access Journals (Sweden)

    AJ Toselli

    2003-12-01

    Full Text Available Las rocas calcosilicáticas y granulíticas, muestran tipologías diferentes en los sectores occidental y oriental de las Sierras Pampeanas Noroccidentales. Las asociaciones minerales difieren según el grado metamórfico y las composiciones químicas varían desde ricas en óxido de calcio a ricas en sílice; siendo diferentes de las anfibolitas. Las rocas calcosilicáticas en las Cumbres Calchaquíes, Aconquija y Ancasti muestran paragénesis con cuarzo, plagioclasa, clinozoicita, granate, hornblenda, titanita, diópsido, biotita y calcita; mientras que en la sierra de Quilmes, en facies granulita, se presenta hipersteno y escasa biotita. Ambas son diferentes de las rocas calcosilicáticas de la sierra de Fiambalá. Los datos geocronológicos obtenidos, permiten correlacionar al evento de muy bajo-bajo grado metamórfico de la Formación Puncoviscana, con edades de 530-568 Ma, con sus equivalentes más profundos en la sierra de Quilmes, representados por rocas calcosilicáticas de 571 Ma, granulitas con 480 Ma y las relacionadas con fenómenos anatécticos y graníticos con edades de 453 Ma (Granito Cafayate y 446 Ma (Loma Colorada, típicas para el Ciclo Famatiniano. Esto se reitera en la tonalita El Infiernillo, de 419 Ma, en las granodioritas sintectónicas de la Formación El Portezuelo, con 445 Ma; en el gneis de La Puntilla de Copacabana con 483 Ma y en el gneis de la sierra de Fiambalá con 440 Ma. Asimismo la faja de deformación de la sierra de Copacabana, con una edad de 388 Ma, se relaciona con los granitos de Zapata de 395 Ma, y los de La Punta, de 405 Ma y Señor de la Peña, 376 Ma, en la sierra de Velasco. Esto muestra que metamorfismo, deformación y magmatismo del Ciclo Famatiniano, se sobreimponen al Ciclo Pampeano.

  2. Variaciones texturales y movilidad geoquímica asociadas a milonitización: la zona de cizalla del granitoide El Tigre, Sierra de Pie de Palo, Sierras Pampeanas Occidentales, San Juan Textural variations and chemical mobility during mylonitization: The El Tigre granitoid shear zone, Sierra de Pie de Palo, western sierras pampeanas, San Juan

    Directory of Open Access Journals (Sweden)

    Brígida Castro De Machuca

    2010-03-01

    Full Text Available Una faja de cizalla dúctil con foliación milonítica de dirección NEE y buzamiento al sudeste, afecta a un granitoide mesoproterozoico (Granitoide El Tigre: 31º31'30''S-68º15'12''O que forma parte del basamento cristalino de la Sierra de Pie de Palo, Sierras Pampeanas Occidentales. El análisis cinemático de la faja indica una componente principal de desplazamiento de rumbo con sentido de movimiento dextral. En el granitoide no deformado (protolito se preservan asociaciones minerales y texturas relícticas, ígneas y metamórficas, que son obliteradas por la deformación. La milonitización operó en un sistema abierto provocando la movilización (ganancia o pérdida de casi todos los elementos mayores y traza, incluyendo las tierras raras e isótopos de Rb/Sr y Sm/Nd. Los cambios químicos fueron controlados mayormente por transporte sintectónico de fluidos y por transformaciones mineralógicas producidas durante la milonitización (disminución del contenido de granate, biotita y minerales accesorios y neoformación de mica blanca en la matriz de las milonitas. Las variaciones isotópicas entre el protolito y las milonitas también serían resultado de la intervención de fluidos durante la deformación, con interacción variable entre fluido y rocas de caja. Los cambios texturales, mineralógicos y químicos experimentados por el granitoide durante la milonitización, permiten reconstruir su evolución tectono-metamórfica y las condiciones metamórficas imperantes. Las asociaciones minerales y microestructuras de deformación de las milonitas sugieren para la faja de cizalla del granitoide El Tigre condiciones propias de la facies de esquistos verdes, con temperaturas inferiores a los 400 °C. Este evento deformante tuvo lugar a los 473 ± 10 Ma durante la orogenia Famatiniana.A high-strain ductile shear zone trending NEE with southeasterly dipping mylonitic foliation, has been recognized affecting a Mesoproterozoic (ca. 1105 Ma

  3. F-rich strongly peraluminous A-type magmatism in the pre-Andean foreland Sierras Pampeanas, Argentina: Geochemical, geochronological, isotopic constraints and petrogenesis

    Science.gov (United States)

    Morales Cámera, Matías M.; Dahlquist, Juan A.; Basei, Miguel A. S.; Galindo, Carmen; da Costa Campos Neto, Mario; Facetti, Nicolás

    2017-04-01

    The petrogenetic nature of A-type granites is a controversial problem. The Vinquis batholith in the Sierras Pampeanas of Argentina contains unusual F-rich and strongly peraluminous A-type monzogranites. A new LA-MC-ICP-MS U-Pb zircon crystallization age of 355 ± 7 Ma indicates emplacement in latest Devonian or earliest Carboniferous time, overlapping with extensive metaluminous A-type magmatism in the area. The monzogranites have a restricted range of SiO2 content (71.5-74.8 %), they are poor in Ca (0.54-1.4% CaO) and rich in FeOt, with relatively high FeOt/(FeOt+MgO) values ranging from 0.77 to 0.86 (average = 0.80) Both [FeOt/ (FeOt+MgO)] vs. SiO2 and [(Na2O+K2O)-CaO] vs. SiO2 plots indicate ferroan and alkali-calcic signatures typical of A-type granitoids. The samples have MgO/TiO2 > 1.2 and are moderately enriched in total alkalis (average 8.18%), with high K2O/Na2O values of 1.40-2.24. The granites are strongly peraluminous, with ASI (molar Al2O3/[CaO + Na2O + K2O]) values of 1.2 to 1.3. The high P2O5 content (0.23-0.37%) is distinctive and close to values reported for other Paleozoic F-rich peraluminous A-type granites in the Sierras Pampeanas. They have moderate contents of high field strength elements (e.g., Zr, Nb, Th, Y, etc.) and moderately fractionated to flat REE patterns [(La/Yb)N in the range 4.8-19.6] showing significant negative Eu anomalies (Eu/Eu* = 0.41). Biotite has a distinctive composition, with relatively high Fe2 +/(Fe2 + + Mg) ratios (0.61-0.74) and high F (0.55-1.42 wt.%) content. Together with the whole-rock chemistry this may be useful in identifying strongly peraluminous A-type granites. In addition, the Rb/Sr vs. Th + Zr + Ce diagram may be an appropriate discriminant between metaluminous and peralkaline A-type granites, strongly peraluminous A-type granites and strongly peraluminous orogenic granites. The geochemical evidence indicates that differentiation of the granitic rocks occurred by mineral fractionation from a F

  4. Volcanismo postorogénico en el extremo norte de las Sierras Pampeanas Orientales: Nuevos datos geocronológicos y sus implicancias tectónicas

    Directory of Open Access Journals (Sweden)

    PR Leal

    2003-12-01

    Full Text Available Este trabajo presenta nuevos datos geocronológicos del sector norte de las Sierras Pampeanas Orientales, en la provincia de Santiago del Estero. La geología regional del área está caracterizada por una serie de granitoides de edad proterozoica tardía a cámbrica temprana que son intruidos por rocas volcánicas supracorticales. Un cuerpo riodacítico, emplazado discordantemente en granitos deformados, asignado a la Dacita Los Burros, está densamente intruido por diques riolíticos, conocidos como Riolitas Oncán, ampliamente expuestos en la sierra de Ambargasta. Estas rocas volcánicas fueron emplazadas después de un importante episodio de deformación y exhumación del batolito, que ocurrió durante la orogenia pampeana. Datos geocronológicos, obtenidos de circones de la Dacita Los Burros por SHRIMP II, permitieron determinar que este cuerpo ha terminado su cristalización alrededor de 512 ± 3,5 Ma, con un evento hidrotermal superpuesto de 481 ± 1,5 Ma. Este efecto hidrotermal ha sido interpretado como asociado al emplazamiento de las Riolitas Oncán. Basados en datos estructurales, análisis geoquímicos y petrológicos previos y los nuevos datos, es posible interpretar la existencia de un arco magmático en las Sierras Pampeanas Orientales desarrollado durante el Precámbrico tardío al Cámbrico temprano, como resultado de una subducción hacia el este del terreno Pampia. La colisión de este terreno controló la deformación principal y el metamorfismo alrededor de 530 Ma, la exhumación del batolito y el emplazamiento de las series volcánicas ácidas aquí descriptas durante el Cámbrico inferior. A su vez, las edades modelos Sm-Nd compiladas para el centro de la Argentina y áreas adyacentes, junto con el análisis aquí presentado, muestran dos basamentos diferentes: edades modelo entre 1800 y 1300 Ma están concentradas al oeste de la zona de cizalla transbrasiliana, mientras que en el sector oriental edades modelos entre 2000

  5. Geoquímica de ríos de montaña en las Sierras Pampeanas: II. El río Los Reartes, sierra de Comenchingones, provincia de Córdoba Geochemistry of mountain rivers in the Sierras Pampeanas: II. Los Reartes River, Sierra de Comenchingones, Province of Córdoba.

    Directory of Open Access Journals (Sweden)

    Andrea I. Pasquini

    2004-03-01

    Full Text Available Se analiza la hidrogeoquímica de la cuenca del río Los Reartes, un típico sistema hídrico montañoso de las Sierras Pampeanas de Córdoba. La litología dominante está representada por rocas graníticas y gnéisicas del basamento. La altitud máxima es de 2.400 m s.n.m. y la mínima de 670 m s.n.m. Las pendientes decrecen desde el 20% en las nacientes hasta inferiores al 6% en las áreas bajas. El clima es semiárido con una concentración estival de las precipitaciones. El pH de las aguas varía de 6,9 a 9,1 y los sólidos totales disueltos (STD oscilan entre 31 y 114 mg/l. La composición mayoritaria está caracterizada por HCO3- > Cl-+ SO42- y Na++ Ca2+ > K++ Mg2+. El pH, los STD y la alcalinidad aumentan aguas abajo, las aguas evolucionan de bicarbonatadas sódicopotásicas a cálcicas. Los elementos traza disueltos tienen concentraciones de 10-3a 10-7 veces la corteza continental superior. Los más solubles (Ca, Na, K, Mg, Ba, Sr presentan las mayores concentraciones disueltas, mientras los más inmóviles exhiben las más bajas. Los elementos de tierras raras (ETR exhiben concentraciones disueltas extremadamente bajas (ΣETR de 30 a 319 ng/l, controladas principalmente por el pH y por procesos de adsorción. La distribución anual irregular de las precipitaciones ejerce un control estacional sobre las concentraciones. La química de estas aguas evidencia un control climático y litológico. La condición climática semiárida determina una incipiente alteración química de los silicatos y la litología constituye el factor determinante que imprime una señal química común a las aguas de la región.We analyzed the hydrogeochemistry of Río Los Reartes, a typical high-altitude, mountainous drainage basin in the Sierras Pampeanas of Córdoba, Argentina. The dominant rocks in the area are granites and gneisses of the crystalline basement. Maximum and minimum altitudes are 2,400 m, and 670 m above sea level, respectively. The slopes

  6. Influencia de la tectónica preandina sobre la tectónica andina: el caso de la falla de Sierra Chica, Sierras Pampeanas de Córdoba

    Directory of Open Access Journals (Sweden)

    Roberto D Martino

    2012-06-01

    Full Text Available La falla de la Sierra Chica es una de las fallas inversas terciarias más importantes de las Sierras Pampeanas de Córdoba. La deformación frágil andina habría sido controlada parcialmente por estructuras previas como la foliación regional del basamento metamórfico proterozoico tardío-cámbrico. Otro control importante está dado por la tectónica extensional cretácica que produjo la apertura del océano Atlántico. La traza actual de la falla presenta tramos rectos, de alto ángulo (~50-60° y vinculados con depósitos cretácicos, que son interpretados como resultado de la reactivación de fallas directas previas, y tramos curvos de bajo ángulo (~30°, que no se asocian a ningún depósito en particular, que serían nuevas fallas inversas originadas por la tectónica terciaria. Una serie de fajas miloníticas antiguas, oblicuas al rumbo general, denominadas lineamientos Carapé, Quebrada Honda y Soconcho, producen la segmentación general de la falla de la Sierra Chica en tres grandes láminas de corrimiento. Durante la compresión terciaria, dichos lineamientos fueron reactivados como fallas de deslizamiento de rumbo dextral, que actuaron como rampas laterales mientras las láminas de corrimiento se desplazaban en sentido NNO (~N 330°. La forma convexa hacia el oeste se debería al efecto del fallamiento inverso de bajo ángulo asociado a la expansión de la parte frontal de la lámina de corrimiento. Las diferencias geobarométricas actuales (~5000 m entre los bloques exhumados a ambos lados de la falla de la Sierra Chica, a la latitud de Alta Gracia (31º 36' S, todavía reflejarían los efectos de la tectónica extensional cretácica, no compensados por la inversión terciaria.

  7. Texturas, inclusiones fluidas e isótopos estables envetas tensionales cuarzo-auríferas de cizallas paleozoicas, Sierras Pampeanas Orientales

    Directory of Open Access Journals (Sweden)

    Diana Mutti

    2009-06-01

    lafase final de la orogenia achaliana. El estudio avala también, la participaciónde aguas meteóricas durante el estadio4 final, debido entre otros,al alzamiento gradual de las Sierras Pampeanas desde el Devónico.

  8. Evolución metalogenética de las Sierras Pampeanas de Córdoba y sur de Santiago del Estero: Ciclos prepampeano y pampeano

    Directory of Open Access Journals (Sweden)

    D. Mutti

    2005-03-01

    Full Text Available La hipótesis de evolución metalogenética de las Sierras Pampeanas de Córdoba y sur de Santiago del Estero propone cinco estadios metalogenéticos, de los cuales los dos primeros se abordan en este trabajo: el estadio 1 - vinculado con la apertura y expansión neoproterozoica del océano proto-atlántico - forma parte del ciclo extensional prepampeano. Durante el mismo se generaron depósitos volcanogénicos submarinos de Cu-Fe (Zn-Au-Ag-Co en basaltos, W (B-F-Zn en calizas y dolomías impuras y Fe en sedimentos silicoclásticos, y manifestaciones transicionales entre estos y MVT de Cu (Au-Ag y Pb-Zn (Ag-Cu-Au en calizas y dolomías impuras; a él se asocian concentraciones magmáticas de Cr en tectonitas del manto y de Fe-Ti en ultramafitas-mafitas de la zona de transición corteza-manto. En una reconstrucción global neoproterozoica, se establece la distribución de los depósitos prepampeanos y su relación espacial con los principales distritos volcanogénicos submarinos, SEDEX y MVT del océano protoatlántico. El ciclo compresional pampeano - famatiniano comprende dos estadios. El estadio metalogenético 2 (Neoproterozoico - Cámbrico temprano corresponde al ciclo orogénico pampeano, durante el cual se desarrollaron numerosas estructuras deformaciónales y magmatismo, generandose manifestaciones magmático-metamórficas de Fe-Ti en diques ultramáficos y máficos en tectonitas del manto, manifestaciones metasomáticas de Fe-Ti en rodingitas y pegmatitas portadoras de Be-Li-U-ETR, ademas de transformaciones (metamorfismo, deformación, removilización y recristalización en depósitos de Cr, Cu-Fe (Zn-Au-Ag-Co, W (B-F-Zn, Cu (Au-Ag, Pb-Zn (Ag-Cu-Au y Fe, que condicionan su respuesta magnética. Para los depósitos y manifestaciones de los estadios metalogenéticos descriptos se propone una distribución espacial según fajas vinculadas con megaestructuras activas a partir de los ciclos prepampeano y pampeano, y las asociaciones petrogen

  9. The Ordovician Sierras Pampeanas-Puna basin connection: Basement thinning and basin formation in the Proto-Andean back-arc

    Science.gov (United States)

    Büttner, Steffen H.

    2009-11-01

    The Ordovician Sierras Pampeanas, located in a continental back-arc position at the Proto-Andean margin of southwest Gondwana, experienced substantial mantle heat transfer during the Ordovician Famatina orogeny, converting Neoproterozoic and Early Cambrian metasediments to migmatites and granites. The high-grade metamorphic basement underwent intense extensional shearing during the Early and Middle Ordovician. Contemporaneously, up to 7000 m marine sediments were deposited in extensional back-arc basins covering the pre-Ordovician basement. Extensional Ordovician tectonics were more effective in mid- and lower crustal migmatites than in higher levels of the crust. At a depth of about 13 km the separating boundary between low-strain solid upper and high-strain lower migmatitic crust evolved to an intra-crustal detachment. The detachment zone varies in thickness but does not exceed about 500 m. The formation of anatectic melt at the metamorphic peak, and the resulting drop in shear strength, initiated extensional tectonics which continued along localized ductile shear zones until the migmatitic crust cooled to amphibolite facies P-T conditions. P-T-d-t data in combination with field evidence suggest significant (ca. 52%) crustal thinning below the detachment corresponding to a thinning factor of 2.1. Ductile thinning of the upper crust is estimated to be less than that of the lower crust and might range between 25% and 44%, constituting total crustal thinning factors of 1.7-2.0. While the migmatites experienced retrograde decompression during the Ordovician, rocks along and above the detachment show isobaric cooling. This suggests that the magnitude of upper crustal extension controls the amount of space created for sediments deposited at the surface. Upper crustal extension and thinning is compensated by newly deposited sediments, maintaining constant pressure at detachment level. Thinning of the migmatitic lower crust is compensated by elevation of the crust

  10. Las fajas de deformación dúctil de las Sierras Pampeanas de Córdoba: Una reseña general

    Directory of Open Access Journals (Sweden)

    RD Martino

    2003-12-01

    Full Text Available Se describen dieciseis fajas de deformación dúctil, reconocidas hasta el momento en las sierras de Córdoba, atendiendo a su extensión, límites, descripción general de las rocas de falla que la conforman, estructura interna y se da un significado tectónico que permite asignarlas a cuatro grupos. (1 Fajas transcurrentes dextrales paralelas al arco magmático precámbrico-cámbrico, relacionadas con la subducción pampeana durante el Cámbrico inferior. (2 Fajas de desenraizamiento del Orógeno Pampeano cámbrico, de naturaleza inversa, producidas por cizalla general convergente (transpresión, relacionadas con etapas póstumas colisionales del terreno Pampia contra el margen de Gondwana y con la subducción famatiniana. Su actividad deformacional se constriñe al lapso 490-470 Ma. (3 Fajas de imbricación regional con generación de cabalgamientos con un fuerte control reológico, ligadas a la contracción oclóyica (Ordovícico superior-Silúrico inferior, de naturaleza inversa, que determinan dominios de edad. De este a oeste, se definen: los dominios precámbrico-cámbrico (ígneo, cámbrico (metamórfico de grado medio a alto y ordovícico (metamórfico de grado medio a alto. Estas fajas estarían relacionadas con el acercamiento del terreno Cuyania al margen gondwánico, antes de su emplazamiento y colisión final en el Ordovícico superior. (4 Fajas contraccionales achalianas, con cinemáticas que indican movimientos inversos con una actividad deformacional que se extendería hasta el Devónico inferior, coincidente con la amalgamación definitiva del terreno Cuyania y con el cese del magmatismo famatiniano. Posteriormente, se registra una reactivación importante o el desarrollo de nuevas fajas de deformación alrededor del límite Devónico-Carbonífero, que serían la expresión de la orogenia Chánica producida por el emplazamiento del terreno Chilenia en el margen gondwánico.

  11. Variaciones texturales y movilidad geoquímica asociadas a milonitización: la zona de cizalla del granitoide El Tigre, Sierra de Pie de Palo, Sierras Pampeanas Occidentales, San Juan

    Directory of Open Access Journals (Sweden)

    Brígida Castro De Machuca

    2010-03-01

    Full Text Available Una faja de cizalla dúctil con foliación milonítica de dirección NEE y buzamiento al sudeste, afecta a un granitoide mesoproterozoico (Granitoide El Tigre: 31º31'30''S-68º15'12''O que forma parte del basamento cristalino de la Sierra de Pie de Palo, Sierras Pampeanas Occidentales. El análisis cinemático de la faja indica una componente principal de desplazamiento de rumbo con sentido de movimiento dextral. En el granitoide no deformado (protolito se preservan asociaciones minerales y texturas relícticas, ígneas y metamórficas, que son obliteradas por la deformación. La milonitización operó en un sistema abierto provocando la movilización (ganancia o pérdida de casi todos los elementos mayores y traza, incluyendo las tierras raras e isótopos de Rb/Sr y Sm/Nd. Los cambios químicos fueron controlados mayormente por transporte sintectónico de fluidos y por transformaciones mineralógicas producidas durante la milonitización (disminución del contenido de granate, biotita y minerales accesorios y neoformación de mica blanca en la matriz de las milonitas. Las variaciones isotópicas entre el protolito y las milonitas también serían resultado de la intervención de fluidos durante la deformación, con interacción variable entre fluido y rocas de caja. Los cambios texturales, mineralógicos y químicos experimentados por el granitoide durante la milonitización, permiten reconstruir su evolución tectono-metamórfica y las condiciones metamórficas imperantes. Las asociaciones minerales y microestructuras de deformación de las milonitas sugieren para la faja de cizalla del granitoide El Tigre condiciones propias de la facies de esquistos verdes, con temperaturas inferiores a los 400 °C. Este evento deformante tuvo lugar a los 473 ± 10 Ma durante la orogenia Famatiniana.

  12. Plutón La Costa, una expresión de magmatismo tipo-s en el sector noreste de la Sierra de Velasco, Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    P.H. Alasino

    2006-06-01

    Full Text Available Estudios combinados de petrología, química mineral y geoquímcia de roca total revelan la presencia de dos unidades graníticas peraluminosas con minerales aluminosos magmáticos tales como granate y mica blanca y la presencia distintiva de turmalina. Las evidencias aquí presentadas indican que estas dos facies, Anillaco y Anjullón, junto a la unidad peraluminosa Santa Cruz estudiada en trabajos previos, constituyen una serie de rocas co-sanguíneas, emplazadas en niveles someros de la corteza y las cuales conforman una unidad ígnea mayor denominada aquí plutón La Costa, la cual aflora en el sector noreste de la sierra de Velasco. La asociación mineral, la química mineral y la geoquímica de roca total permiten definir al plutón La Costa como un clásico granitoide tipo-S, derivado de una roca fuente de composición esencialmente pelítica. Diferentes estudios demuestran que la generación de granitoides tipo-S requiere de un alto gradiente geotérmico, por lo cual el plutón La Costa indica que la corteza en esta región soportó un notable calentamiento durante la generación del magma. Sin embargo, la ausencia de datos geocronológicos impide definir el evento tectomagmático que produjo el magma primordial de este plutón.

  13. Evolución metalogenética de las Sierras Pampeanas de Córdoba y sur de Santiago del Estero: Ciclos famatiniano, gondwánico y ándico Metallogenic evolution of the Sierras Pampeanas of Córdoba and south of Santiago del Estero: Famatinian, Gondwanic and Andean cycles

    Directory of Open Access Journals (Sweden)

    D. Mutti

    2005-09-01

    Full Text Available Se propone la evolución metalogenética de las Sierras Pampeaneas de Córdoba y sur de Santiago del Estero en cinco estadios, de los cuales los dos primeros se expusieron en un trabajo anterior. El estadio metalogenético 3, que corresponde al segundo ciclo orogénico del Pampeano-Famatiniano, se caracterizó por la migración de fluidos hidrotermales y la generación y reactivación de estructuras. Durante el mismo sucedieron transformaciones en depósitos de Cr (Fe-Ti, Cu (Au-Ag, Pb-Zn (Ag-Cu-Au, Fe y Cu- Fe (Zn-Au-Ag-Co, y se originaron pegmatitas portadoras de Be-Nb-Ta-W-P-U-ETR, depósitos biextendidos de W-Bi (Mo-Cu-Sn- Zn-Au-B-F-Te y de U asociados a granitoides, depósitos metasomáticos de Fe-Cu (Ti-Au y vetas de Au (Cu-Zn-Pb-As y polimetálicas de Ag-Pb-Zn (V-Sn-Mn-Cd-Au-Cu-As-Bi-Sb-Co. Para este estadio se establece una correlación con depósitos en cinturones orogénicos. El estadio metalogenético 4, correspondiente al ciclo extensional gondwánico y vinculado con la apertura del rifting Atlántico, formó depósitos de Mn (Fe-F-Ba en vetas y de F (Fe-Mn en vetas asociados con granitos. El estadio metalogenético 5 se desarrolló durante el ciclo compresional Ándico y generó manifestaciones de Au epitermal y depósitos y manifestaciones de U-V (Mn-Fe en sedimentitas. Los sucesivos estadios de depositación y movilización de elementos metálicos definieron fajas mineralizadas que otorgan a este sector de las Sierras Pampeanas un carácter de dominio especializado en Cr, W, Fe, Cu, Zn, Pb, Ti, Au, Bi, Be, Li, U, Mn, F y B y subordinado en Sn, Mo, ETR, Ta, Nb, V, Cd, Ag, Sb, Co, P, As, S, Te, Se y Ba.Five metallogenic stages are proposed for the metallogenic evolution of the Sierra Pampeaneas of Córdoba and south of Santiago del Estero, havin. having already been exposed the first two previous work. Metallogenic stage 3, corresponding to the second orogenic cycle of the Pampean-Famatinian compressive cycle, was characterized by

  14. Geoquímica de ríos de montaña en las Sierras Pampeanas: II. El río Los Reartes, sierra de Comenchingones, provincia de Córdoba

    Directory of Open Access Journals (Sweden)

    Andrea I. Pasquini

    2004-03-01

    Full Text Available Se analiza la hidrogeoquímica de la cuenca del río Los Reartes, un típico sistema hídrico montañoso de las Sierras Pampeanas de Córdoba. La litología dominante está representada por rocas graníticas y gnéisicas del basamento. La altitud máxima es de 2.400 m s.n.m. y la mínima de 670 m s.n.m. Las pendientes decrecen desde el 20% en las nacientes hasta inferiores al 6% en las áreas bajas. El clima es semiárido con una concentración estival de las precipitaciones. El pH de las aguas varía de 6,9 a 9,1 y los sólidos totales disueltos (STD oscilan entre 31 y 114 mg/l. La composición mayoritaria está caracterizada por HCO3- > Cl-+ SO42- y Na++ Ca2+ > K++ Mg2+. El pH, los STD y la alcalinidad aumentan aguas abajo, las aguas evolucionan de bicarbonatadas sódicopotásicas a cálcicas. Los elementos traza disueltos tienen concentraciones de 10-3a 10-7 veces la corteza continental superior. Los más solubles (Ca, Na, K, Mg, Ba, Sr presentan las mayores concentraciones disueltas, mientras los más inmóviles exhiben las más bajas. Los elementos de tierras raras (ETR exhiben concentraciones disueltas extremadamente bajas (ΣETR de 30 a 319 ng/l, controladas principalmente por el pH y por procesos de adsorción. La distribución anual irregular de las precipitaciones ejerce un control estacional sobre las concentraciones. La química de estas aguas evidencia un control climático y litológico. La condición climática semiárida determina una incipiente alteración química de los silicatos y la litología constituye el factor determinante que imprime una señal química común a las aguas de la región.

  15. Depósitos polimetálicos en el orógeno famatiniano de las Sierras Pampeanas de San Luis y Córdoba: fluidos, fuentes y modelos de emplazamiento Polymetallic deposits in the Famatinian orogen of the Sierras Pampeanas of San Luis and Córdoba: fluids, sources and emplacement model

    Directory of Open Access Journals (Sweden)

    D. Mutti

    2007-11-01

    Full Text Available El ciclo orogénico famatinano originó en las Sierras Pampeanas de San Luis y Córdoba un episodio mineralizante relacionado con cizallas de rumbo norte de primer orden y granitoides entre los ~ 385 y ~ 292 Ma. Este episodio definió dominios lineales polimetálicos de W, Ag, Pb, Zn, Au y metales asociados, en metamorfitas y minoritariamente en granitoides. En depósitos representativos de San Luis y Córdoba, los valores de d18Ofluido(H2O y dDfluido(H2O en silicatos, señalan para los fluidos mineralizantes, una filiación magmática y con aguas meteóricas evolucionadas. Las determinaciones de d34Sfluido (H2S en sulfuros sugieren la incorporación del azufre por termoreducción desde las metasedimentitas corticales. Las relaciones 208Pb/204Pb - 207Pb/204Pb - 206Pb/204Pb indican el aporte de Pb desde la corteza continental fanerozoica homogeneizada, aunque en La Fortuna (distrito Las Aguadas, La Aspereza (distrito San Martín y Fischer (distrito Cerro Áspero, se comprobó además, un componente mantélico. Las estructuras tensionales mineralizadas, con orientación mayoritaria entre 250º y 319º y geometría interna escalonada (en echelón, responden al modelo Riedel en zonas de cizalla simple. Estas estructuras secundarias se desarrollaron en un ambiente extensional frágil - dúctil a frágil y en un regimen transpresivo, durante un esfuerzo máximo principal s1 NO - SE y el alzamiento de la región. Las características halladas sugieren que el magmatismo famatiniano sinorogénico a posorogénico, ocasionó anomalías térmicas que propiciaron la circulación hidrotermal en sistemas convectivos. El flujo acuoso se encauzó principalmente, por la estructura de primer orden Tres Árboles y lineamientos secundarios. No se encontraron evidencias de que el magmatismo granítico hubiera contribuido significativamente con el aporte de azufre y elementos metálicos, al menos en este estilo de depósitos con marcado control estructural

  16. Plutón La Costa, una expresión de magmatismo tipo-s en el sector noreste de la Sierra de Velasco, Sierras Pampeanas La Costa pluton, an expresion of S- type magmatism in the northeastern sector of the Sierra de Velasco, Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    P.H. Alasino

    2006-06-01

    Full Text Available Estudios combinados de petrología, química mineral y geoquímcia de roca total revelan la presencia de dos unidades graníticas peraluminosas con minerales aluminosos magmáticos tales como granate y mica blanca y la presencia distintiva de turmalina. Las evidencias aquí presentadas indican que estas dos facies, Anillaco y Anjullón, junto a la unidad peraluminosa Santa Cruz estudiada en trabajos previos, constituyen una serie de rocas co-sanguíneas, emplazadas en niveles someros de la corteza y las cuales conforman una unidad ígnea mayor denominada aquí plutón La Costa, la cual aflora en el sector noreste de la sierra de Velasco. La asociación mineral, la química mineral y la geoquímica de roca total permiten definir al plutón La Costa como un clásico granitoide tipo-S, derivado de una roca fuente de composición esencialmente pelítica. Diferentes estudios demuestran que la generación de granitoides tipo-S requiere de un alto gradiente geotérmico, por lo cual el plutón La Costa indica que la corteza en esta región soportó un notable calentamiento durante la generación del magma. Sin embargo, la ausencia de datos geocronológicos impide definir el evento tectomagmático que produjo el magma primordial de este plutón.Combined petrology, mineral chemistry and whole-rock geochemistry studies reveal the presence of two peraluminous granitic units with magmatic aluminous minerals, such as garnet and white mica, and the distinctive presence of tourmaline. The evidence presented here indicates that these two facies, Anillaco and Anjullón, together with the peraluminous Santa Cruz unit studied in previous works, constitute co-sanguineous rocks, emplacemed in shallow levels of the crust, conforming a greater igneous unit, named here as La Costa pluton, that outcrops in the northeast sector of the sierra de Velasco. The mineral assemblage, the mineral chemistry and the whole-rock geochemistry allow defining the La Costa pluton as

  17. Geoquímica de ríos de montaña en las Sierras Pampeanas: I. Vertientes y arroyos del batolito de Achala, provincia de Córdoba, Argentina Geochemistry of mountain rivers in the Sierras Pampeanas: I. Springs and streams in the Achala batholith, Córdoba province, Argentina

    Directory of Open Access Journals (Sweden)

    A. I. Pasquini

    2002-12-01

    Full Text Available Se analiza la composición química de vertientes y arroyos de altura (>1100 m s.n.m. sobre el batolito de Achala en las Sierras Pampeanas de Córdoba, donde la litología dominante es un monzogranito porfírico. El agua tiene una composición mayoritaria bicarbonatada/sódico-potásica a cálcica. La concentración de los elementos disueltos tiene un orden de magnitud entre 10³ y 10(7 veces inferior a la corteza continental superior y al granito dominante. La concentración de los elementos químicos está vinculada con el grado de movilidad de los mismos bajo condiciones de meteorización incipiente. Los elementos más móviles (alcalinos y alcalinotérreos presentan las concentraciones más elevadas en el agua y en la roca, mientras los más inmóviles (Al, Ga, Ti, Zr, Hf, Th y tierras raras exhiben las más bajas. Ambos grupos de elementos están sujetos a un control litológico significativo. Los metales de transición, tienen solubilidades y concentraciones variables, sugiriendo la existencia de otros controles además del litológico. Los iones mayoritarios evidencian una dilución estival cercana al 60%, mientras que los elementos traza manifiestan un incremento de sus concentraciones por movilización durante el período estival. Las características geológicas de la región, junto con su condición climática semiárida, favorecen el predominio de un régimen de denudación "limitado por la meteorización", donde los procesos de erosión física predominan sobre la meteorización química. Bajo estas condiciones, las características geoquímicas del agua en la región, escasamente afectada por la actividad antrópica, ponen de manifiesto el control que ejercen la litología y el relieve sobre las mismas.The chemical composition of mountainous (>1,100 m a.s.l. springs and streams from the Achala batholith, in the Pampean Range of Córdoba, Argentina are analized; in this area, the most important lithology is porphyritic monzogranite

  18. Evolución metalogenética de las Sierras Pampeanas de Córdoba y sur de Santiago del Estero: Ciclos prepampeano y pampeano Metallogenic evolution of the Sierras Pampeanas of Córdoba and south of Santiago del Estero: Prepampean and Pampean cycles

    Directory of Open Access Journals (Sweden)

    D. Mutti

    2005-03-01

    Full Text Available La hipótesis de evolución metalogenética de las Sierras Pampeanas de Córdoba y sur de Santiago del Estero propone cinco estadios metalogenéticos, de los cuales los dos primeros se abordan en este trabajo: el estadio 1 - vinculado con la apertura y expansión neoproterozoica del océano proto-atlántico - forma parte del ciclo extensional prepampeano. Durante el mismo se generaron depósitos volcanogénicos submarinos de Cu-Fe (Zn-Au-Ag-Co en basaltos, W (B-F-Zn en calizas y dolomías impuras y Fe en sedimentos silicoclásticos, y manifestaciones transicionales entre estos y MVT de Cu (Au-Ag y Pb-Zn (Ag-Cu-Au en calizas y dolomías impuras; a él se asocian concentraciones magmáticas de Cr en tectonitas del manto y de Fe-Ti en ultramafitas-mafitas de la zona de transición corteza-manto. En una reconstrucción global neoproterozoica, se establece la distribución de los depósitos prepampeanos y su relación espacial con los principales distritos volcanogénicos submarinos, SEDEX y MVT del océano protoatlántico. El ciclo compresional pampeano - famatiniano comprende dos estadios. El estadio metalogenético 2 (Neoproterozoico - Cámbrico temprano corresponde al ciclo orogénico pampeano, durante el cual se desarrollaron numerosas estructuras deformaciónales y magmatismo, generandose manifestaciones magmático-metamórficas de Fe-Ti en diques ultramáficos y máficos en tectonitas del manto, manifestaciones metasomáticas de Fe-Ti en rodingitas y pegmatitas portadoras de Be-Li-U-ETR, ademas de transformaciones (metamorfismo, deformación, removilización y recristalización en depósitos de Cr, Cu-Fe (Zn-Au-Ag-Co, W (B-F-Zn, Cu (Au-Ag, Pb-Zn (Ag-Cu-Au y Fe, que condicionan su respuesta magnética. Para los depósitos y manifestaciones de los estadios metalogenéticos descriptos se propone una distribución espacial según fajas vinculadas con megaestructuras activas a partir de los ciclos prepampeano y pampeano, y las asociaciones petrogen

  19. Cambios de gravedad de origen tectónico en la transición entre las Sierras Pampeanas Occidentales y la Precordillera Sanjuanina Gravity changes of tectonic origin in the transition between western Sierras Pampeanas and Precordillera of San Juan.

    Directory of Open Access Journals (Sweden)

    Francisco Ruiz

    2011-12-01

    extends over an area of about 3,500 km2 centered in the San Juan city. Ten years of gravity periodic measurements have allowed to evaluate the speeds of the gravitational intensity field variations. These gravity changes adjust reasonably well with the statistical lineal regression model applied to the gravity versus time observations. The observed data support the current uplift of the Eastern Precordillera, reflected in increases of gravity (g in all bench marks located westwards of the Villicum-Ullum-Zonda fault and in the decrease of gravity eastwards of this structure. We identify three segments of larger activity: a La Laja fault with strong decreases of g, b Maradona-Cerro Bayo segment, with increases of g westwards of the Sierra Chica de Zonda and c decreases of g at La Rinconada fault. The data show tectonic activity in the Tulum faults system, gravity changes have lined up in the Cerro Valdivia-Cerro Barboza-Sierra de Pie de Palo lineament and increase to the east. The largest variations are observed eastwards of the Barboza hill with a minimum of g. Magnetic and gravity anomaly maps indicate basement patterns consistent with these active structures.

  20. Deformation of the late Miocene to Pliocene Inyo Surface, eastern Sierra region, California

    Science.gov (United States)

    Jayko, A.S.

    2009-01-01

    A middle and late Miocene erosion surface, the Inyo Surface, underlies late Miocene mafic flows in the White Mountains and late Miocene and (or) early Pliocene flows elsewhere in the eastern Sierra region. The Inyo Surface is correlated with an erosion surface that underlies late Miocene mafic flows in the central and northern Sierra Nevada. The mafic flows had outpourings similar to flood basalts, although of smaller volume, providing paleohorizontal and paleolowland indicators. The flows filed and locally topped the existing landscape forming broad plateau-like flats. Topographic relief in the region was characterized by weathered and rounded slopesp rior to late Miocene mafic magmatism. Relicts of the older landscape lie adjacent to late Miocene and early Pliocene basalt-covered lowlands that now occur within the crests of ranges that have 2500-3000 m relief and dramatically steep escarpments. Late Miocene mafic flows that lie on the crest of the Sierra Nevada adjacent to the White Mountains predate significant activity on the Sierra Nevada frontal fault zone. These deposits and accompanying erosion surfaces provide excellent strain markers for reconstructing part of the Walker Lane north of the Garlock fault and west of the Amargosa drainage, here referred to as the eastern Sierra region. The Inyo Surface is a compound erosional surface that records at least four major erosion events during the Cenozoic. These four surfaces were first recognized on the Kern Plateau and named from oldest to youngest, the Summit Upland, the Subsummit Plateau, the Chagoopa Plateau, and the Canyon. The three older surfaces have also been subsequently modifi ed by Pleistocene glaciation. The compound erosion surface, which is locally overlain by late Miocene mafic flows in the northern and central Sierra Nevada, is here referred to as the Lindgren Surface. Correlatives in the eastern Sierra region are found in the White Mountains, Inyo Mountains, Darwin Plateau, Coso Range, and

  1. Evolución metalogenética de las Sierras Pampeanas de Córdoba y sur de Santiago del Estero: Ciclos famatiniano, gondwánico y ándico

    Directory of Open Access Journals (Sweden)

    D. Mutti

    2005-09-01

    Full Text Available Se propone la evolución metalogenética de las Sierras Pampeaneas de Córdoba y sur de Santiago del Estero en cinco estadios, de los cuales los dos primeros se expusieron en un trabajo anterior. El estadio metalogenético 3, que corresponde al segundo ciclo orogénico del Pampeano-Famatiniano, se caracterizó por la migración de fluidos hidrotermales y la generación y reactivación de estructuras. Durante el mismo sucedieron transformaciones en depósitos de Cr (Fe-Ti, Cu (Au-Ag, Pb-Zn (Ag-Cu-Au, Fe y Cu- Fe (Zn-Au-Ag-Co, y se originaron pegmatitas portadoras de Be-Nb-Ta-W-P-U-ETR, depósitos biextendidos de W-Bi (Mo-Cu-Sn- Zn-Au-B-F-Te y de U asociados a granitoides, depósitos metasomáticos de Fe-Cu (Ti-Au y vetas de Au (Cu-Zn-Pb-As y polimetálicas de Ag-Pb-Zn (V-Sn-Mn-Cd-Au-Cu-As-Bi-Sb-Co. Para este estadio se establece una correlación con depósitos en cinturones orogénicos. El estadio metalogenético 4, correspondiente al ciclo extensional gondwánico y vinculado con la apertura del rifting Atlántico, formó depósitos de Mn (Fe-F-Ba en vetas y de F (Fe-Mn en vetas asociados con granitos. El estadio metalogenético 5 se desarrolló durante el ciclo compresional Ándico y generó manifestaciones de Au epitermal y depósitos y manifestaciones de U-V (Mn-Fe en sedimentitas. Los sucesivos estadios de depositación y movilización de elementos metálicos definieron fajas mineralizadas que otorgan a este sector de las Sierras Pampeanas un carácter de dominio especializado en Cr, W, Fe, Cu, Zn, Pb, Ti, Au, Bi, Be, Li, U, Mn, F y B y subordinado en Sn, Mo, ETR, Ta, Nb, V, Cd, Ag, Sb, Co, P, As, S, Te, Se y Ba.

  2. Rasgos estructurales en la Sierra Pampeana de Velasco y alrededores a partir de los campos gravimétricos y magnetrométricos

    Directory of Open Access Journals (Sweden)

    Marcos A Sánchez

    2013-06-01

    Full Text Available La región que comprende la sierra de Velasco y el Sistema de Famatina, en el centro-oeste de la Provincia de La Rioja - Argentina, es un área clave para el estudio de la amalgamación de terrenos y tectónica vinculada con el levantamiento andino. En éste trabajo, se definen algunos rasgos de la estructura cortical de ésta región. Para ello, mediante la aplicación de métodos potenciales (gravedad y magnetismo, adecuadamente procesados e interpretados a través de técnicas semiautomáticas y de resalto de anomalías, se logró determinar: a una región que respondería a la zona de sutura entre los terrenos Famatina y Pampia y b fallas relacionadas al levantamiento de las sierras de Famatina y de Velasco. Los resultados anteriores se representan en una sección este - oeste en un modelo estructural de bloques de basamento entre Famatina y Velasco, hasta 12 km de profundidad. En él señalamos además la distribución de las fallas y sus buzamientos.

  3. Actualización en el límite entre sierras Pampeanas occidentales y Precordillera Oriental, en la provincia de San Juan

    Directory of Open Access Journals (Sweden)

    Juvenal J. Zambrano

    2008-03-01

    Full Text Available En este trabajo se analiza el sistema de fallamiento existente en la depresión tectónica de Tulum, ubicada en la parte este y sur de la provincia de San Juan, en el oeste árido de Argentina. El límite entre los dos sistemas morfoestructurales, uno la Precordillera Oriental y el otro el Sistema Pampeano Occidental ha sido establecido en trabajos anteriores, a lo largo del sistema de fallamiento de Tulum, que cruza a la depresión diagonalmente en dirección NNE. No obstante la disponibilidad de nueva información de sondeos eléctricos verticales y de algunas perforaciones para búsqueda de agua subterránea, efectuados al sur y al oeste del cerro Valdivia, permite señalar que hacia el suroeste de este núcleo de basamento metamórfico limitado en ambos flancos por fallas, el límite Sistema Pampeano y Precordillera se aproxima al cordón montañoso de sierra Chica de Zonda, continuando al sur en el cerro Salinas. De allí al SSO existen, en superficie, indicaciones de que el sistema de fallamiento continúa hasta el Montecito, donde el sistema pampeano de fallas queda interrumpido por la gran falla con actividad cuaternaria que sirve de límite oriental a la sierra de Las Peñas. El contacto entre ambos sistemas forma el extremo sur de la Precordillera Oriental en subsuelo. Este conocimiento estructural permite no solo ser aplicado a la prospección de agua sino también a la de hidrocarburos en la región.

  4. Manifestaciones geomorfológicas y geofísicas de una estructura geológica profunda al sur de la Sierra de Pie de Palo, Sierras Pampeanas

    National Research Council Canada - National Science Library

    M. Patricia Martínez; Laura P. Perucca; Mario E. Giménez; Francisco Ruíz

    2008-01-01

    En el presente trabajo se vinculan las evidencias geomorfológicas y geofísicas con la existencia de una estructura emplazada en la corteza superior, ubicada al sur de la sierra de Pie de Palo y con similares dimensiones que ésta...

  5. The Mono Arch, eastern Sierra region, California: Dynamic topography associated with upper-mantle upwelling?

    Science.gov (United States)

    Jayko, A.S.

    2009-01-01

    A broad, topographic flexure localized east of and over the central and southern Sierra Nevada, herein named the Mono Arch, apparently represents crustal response to lithospheric and/or upper-mantle processes, probably dominated by mantle upwelling within the continental interior associated Pacific-North American plate-boundary deformation. This zone of flexure is identified through comparison between the topographic characteristics of the active Cascade volcanic arc and backarc regions with the analogous former arc and backarc in the Sierra Nevada and eastern Sierra Nevada. Serial topographic profiles measured normal to the modern Cascade backarc reveal an accordance of topographic lows defined by valley floors with an average minimum elevation of ???1400-1500m for over 175km to the southeast. Although the accordance drops in elevation slightly to the south, the modern Cascade backarc region is remarkably level, and is characterized by relief up to ???750m above this baseline elevation. By contrast, serial topographic profiles over the former arc and backarc transitions of the eastern Sierra region exhibit a regional anticlinal warping defined by accordant valley floors and by a late Miocene-early Pliocene erosion surface and associated deposits. The amplitude of this flexure above regionally flat baseline elevations to the east varies spatially along the length of the former Sierran arc, with a maximum of ???1000m centred over the Bridgeport Basin. The total zone of flexure is approximately 350km long N-S and 100km wide E-W, and extends from Indian Wells Valley in the south to the Sonora Pass region in the north. Previous geophysical, petrologic, and geodetic studies suggest that the Mono Arch overlies a zone of active mantle upwelling. This region also represents a zone crustal weakness formerly exploited by the middle-to-late Miocene arc and is presently the locus of seismic and volcanic activities. This seismic zone, which lies east of the Sierra Nevada block

  6. Geoquímica de ríos de montaña en las Sierras Pampeanas: I. Vertientes y arroyos del batolito de Achala, provincia de Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    A. I. Pasquini

    2002-12-01

    Full Text Available Se analiza la composición química de vertientes y arroyos de altura (>1100 m s.n.m. sobre el batolito de Achala en las Sierras Pampeanas de Córdoba, donde la litología dominante es un monzogranito porfírico. El agua tiene una composición mayoritaria bicarbonatada/sódico-potásica a cálcica. La concentración de los elementos disueltos tiene un orden de magnitud entre 10³ y 10(7 veces inferior a la corteza continental superior y al granito dominante. La concentración de los elementos químicos está vinculada con el grado de movilidad de los mismos bajo condiciones de meteorización incipiente. Los elementos más móviles (alcalinos y alcalinotérreos presentan las concentraciones más elevadas en el agua y en la roca, mientras los más inmóviles (Al, Ga, Ti, Zr, Hf, Th y tierras raras exhiben las más bajas. Ambos grupos de elementos están sujetos a un control litológico significativo. Los metales de transición, tienen solubilidades y concentraciones variables, sugiriendo la existencia de otros controles además del litológico. Los iones mayoritarios evidencian una dilución estival cercana al 60%, mientras que los elementos traza manifiestan un incremento de sus concentraciones por movilización durante el período estival. Las características geológicas de la región, junto con su condición climática semiárida, favorecen el predominio de un régimen de denudación "limitado por la meteorización", donde los procesos de erosión física predominan sobre la meteorización química. Bajo estas condiciones, las características geoquímicas del agua en la región, escasamente afectada por la actividad antrópica, ponen de manifiesto el control que ejercen la litología y el relieve sobre las mismas.

  7. Depósitos polimetálicos en el orógeno famatiniano de las Sierras Pampeanas de San Luis y Córdoba: fluidos, fuentes y modelos de emplazamiento

    Directory of Open Access Journals (Sweden)

    D. Mutti

    2007-03-01

    Full Text Available El ciclo orogénico famatinano originó en las Sierras Pampeanas de San Luis y Córdoba un episodio mineralizante relacionado con cizallas de rumbo norte de primer orden y granitoides entre los ~ 385 y ~ 292 Ma. Este episodio definió dominios lineales polimetálicos de W, Ag, Pb, Zn, Au y metales asociados, en metamorfitas y minoritariamente en granitoides. En depósitos representativos de San Luis y Córdoba, los valores de d18Ofluido(H2O y dDfluido(H2O en silicatos, señalan para los fluidos mineralizantes, una filiación magmática y con aguas meteóricas evolucionadas. Las determinaciones de d34Sfluido (H2S en sulfuros sugieren la incorporación del azufre por termoreducción desde las metasedimentitas corticales. Las relaciones 208Pb/204Pb - 207Pb/204Pb - 206Pb/204Pb indican el aporte de Pb desde la corteza continental fanerozoica homogeneizada, aunque en La Fortuna (distrito Las Aguadas, La Aspereza (distrito San Martín y Fischer (distrito Cerro Áspero, se comprobó además, un componente mantélico. Las estructuras tensionales mineralizadas, con orientación mayoritaria entre 250º y 319º y geometría interna escalonada (en echelón, responden al modelo Riedel en zonas de cizalla simple. Estas estructuras secundarias se desarrollaron en un ambiente extensional frágil - dúctil a frágil y en un regimen transpresivo, durante un esfuerzo máximo principal s1 NO - SE y el alzamiento de la región. Las características halladas sugieren que el magmatismo famatiniano sinorogénico a posorogénico, ocasionó anomalías térmicas que propiciaron la circulación hidrotermal en sistemas convectivos. El flujo acuoso se encauzó principalmente, por la estructura de primer orden Tres Árboles y lineamientos secundarios. No se encontraron evidencias de que el magmatismo granítico hubiera contribuido significativamente con el aporte de azufre y elementos metálicos, al menos en este estilo de depósitos con marcado control estructural.

  8. Manifestaciones geomorfológicas y geofísicas de una estructura geológica profunda al sur de la Sierra de Pie de Palo, Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    M. Patricia Martínez

    2008-06-01

    Full Text Available En el presente trabajo se vinculan las evidencias geomorfológicas y geofísicas con la existencia de una estructura emplazada en la corteza superior, ubicada al sur de la sierra de Pie de Palo y con similares dimensiones que ésta. A partir de valores de gravedad, se calculó una carta de anomalías de Bouguer, correspondiente a la sierra de Pie de Palo y zonas aledañas. Se aplicó el método de deconvolución de Euler, variando adecuadamente el ancho de ventana entre 20 y 35 km y con dos índices estructurales: 0,5 y 1. Las respuestas obtenidas con este método señalan en ambos casos una concentración de soluciones que se corresponden con rasgos estructurales reconocidos geológicamente como: la megafalla Desaguadero Bermejo; el borde oriental de la Precordillera; la megafractura de El Molle. Por otro lado, existe una gran acumulación de soluciones de forma trapezoidal al sur de la sierra de Pie de Palo. Estas fuentes responden a profundidades en su mayoría ubicadas entre 10 y 20 kilómetros, indicando una cuarta estructura profunda o alto de basamento. Las evidencias geomorfológicas encontradas en la región corroborarían la existencia de esta estructura en ascenso, sugerida por las sucesivas migraciones de los cauces de los ríos San Juan hacia el norte y Mendoza y Tunuyán hacia el sur, tanto en épocas prehistóricas como históricas. Este fenómeno podría compararse con el ocurrido durante el terremoto de 1977, con epicentro en la provincia de San Juan, el cual produjo un ascenso de la sierra de Pie de Palo de 1,20 metros.

  9. Provencance of the late Proterozoic to early Cambrian metaclastic sediments ot the Sierra de San Luis (Eastern Sierras Pampeanas) and Cordillera Oriental, Argentina

    DEFF Research Database (Denmark)

    Drobe, M.; López de Luchi, M.; Steenken, A.

    2009-01-01

    /204Pb values. Possible source rocks for the different domains could be the Quebrada Choja in the Central Arequipa-Antofalla domain, the Southern domain of the Arequipa-Antofalla basement, the Brazilian shield or southern Africa. Zircon SHRIMP data point to a connection between the Puncoviscana...

  10. Mechanical Effects of Normal Faulting Along the Eastern Escarpment of the Sierra Nevada, California

    Science.gov (United States)

    Martel, S. J.; Logan, J. M.; Stock, G. M.

    2013-12-01

    Here we test whether the regional near-surface stress field in the Sierra Nevada, California, and the near-surface fracturing that heavily influences the Sierran landscape are a mechanical response to normal faulting along its eastern escarpment. A compilation of existing near-surface stress measurements for the central Sierra Nevada, together with three new measurements, shows the most compressive horizontal stresses are 3-21 MPa, consistent with the widespread distribution of sheeting joints (near-surface fractures subparallel to the ground surface). In contrast, a new stress measurement at Aeolian Buttes in the Mono Basin, east of the range front fault system, reveals a horizontal principal tension of 0.014 MPa, consistent with the abundant vertical joints there. To evaluate mechanical effects of normal faulting, we modeled both normal faults and grabens in three ways: (1) dislocations of specified slip in an elastic half-space, (2) frictionless sliding surfaces in an elastic half-space; and (3) faults in thin elastic beams resting on an inviscid fluid. The different mechanical models predict concave upward flexure and widespread near-surface compressive stresses in the Sierra Nevada that surpass the measurements even for as little as 1 km of normal slip along the eastern escarpment, which exhibits 1-3 km of structural and topographic relief. The models also predict concave downward flexure of the bedrock floors and horizontal near-surface tensile stresses east of the escarpment. The thin-beam models account best for the topographic relief of the eastern escarpment and the measured stresses given current best estimates for the rheology of the Sierran lithosphere. Our findings collectively indicate that the regional near-surface stress field and the widespread near-surface fracturing directly reflect the mechanical response to normal faulting along the eastern escarpment. These results have broad scientific and engineering implications for slope stability

  11. Crustal wedging triggering recent deformation in the Andean thrust front between 31°S and 33°S: Sierras Pampeanas-Precordillera interaction

    Science.gov (United States)

    VergéS, J.; Ramos, V. A.; Meigs, A.; Cristallini, E.; Bettini, F. H.; CortéS, J. M.

    2007-03-01

    We document a new model of crustal structure of the Andean front in Argentina where numerous historic earthquakes destroyed the cities of Mendoza in 1861 (Ms = ˜7) and San Juan in 1944 (Mw = 7.0). The Cerro Salinas anticline is formed above the west directed Cerro Salinas thrust. An east facing monocline with an amplitude of about 2 km folds the Cerro Salinas thrust and overlying Neogene succession. This monocline is formed above a blind crustal thrust in the basement. Its dip of 14° west is inferred from fold geometry. This thick-skinned east directed blind thrust and the thin-skinned west directed Cerro Salinas thrust define a tectonic wedge; the wedge tip occurs at a depth of 5.4 km. Growth of the monocline after ˜8.5 Ma is revealed on multichannel seismic (MSC) profile 31017 (Repsol-YPF). Rates of Cerro Salinas thrust displacement are of the order of 1 mm/yr, whereas vertical uplift of ˜0.45 mm/yr results from the combined displacement on the Cerro Salinas thrust and growth of east facing monocline. The lateral extent of the east directed crustal blind ramp corresponds with the along-strike extent of the Eastern Precordillera. When combined with the low displacement rate, a long earthquake recurrence interval is implied. Smaller magnitude earthquakes, however, indicate that segments of the blind thrust ramps ruptured in historic events. If all the segments of the blind thrust ruptured together the fault area is ˜7000 km2 and could produce a Mw ˜ 7.7 earthquake. The crustal wedge model provides new constraints on the origin and potential size of earthquakes that threaten the densely populated region.

  12. Vertical Distribution of Ozone and Nitric Acid Vapor on the Mammoth Mountain, Eastern Sierra Nevada, California

    OpenAIRE

    2002-01-01

    In August and September 1999 and 2000, concentrations of ozone (O3) and nitric acid vapor (HNO3) were monitored at an elevation gradient (2184–3325 m) on the Mammoth Mountain, eastern Sierra Nevada, California. Passive samplers were used for monitoring exposure to tropospheric O3 and HNO3 vapor. The 2-week average O3 concentrations ranged between 45 and 72 ppb, while HNO3 concentrations ranged between 0.06 and 0.52 μg/m3. Similar ranges of O3 and HNO3 were determined for 2 years of the study....

  13. Las fajas de deformación dúctil de las Sierras Pampeanas de Córdoba: Una reseña general Ductile deformation shear belts at Pampean Ranges near Córdoba, Central Argentina: A Review

    Directory of Open Access Journals (Sweden)

    RD Martino

    2003-12-01

    Full Text Available Se describen dieciseis fajas de deformación dúctil, reconocidas hasta el momento en las sierras de Córdoba, atendiendo a su extensión, límites, descripción general de las rocas de falla que la conforman, estructura interna y se da un significado tectónico que permite asignarlas a cuatro grupos. (1 Fajas transcurrentes dextrales paralelas al arco magmático precámbrico-cámbrico, relacionadas con la subducción pampeana durante el Cámbrico inferior. (2 Fajas de desenraizamiento del Orógeno Pampeano cámbrico, de naturaleza inversa, producidas por cizalla general convergente (transpresión, relacionadas con etapas póstumas colisionales del terreno Pampia contra el margen de Gondwana y con la subducción famatiniana. Su actividad deformacional se constriñe al lapso 490-470 Ma. (3 Fajas de imbricación regional con generación de cabalgamientos con un fuerte control reológico, ligadas a la contracción oclóyica (Ordovícico superior-Silúrico inferior, de naturaleza inversa, que determinan dominios de edad. De este a oeste, se definen: los dominios precámbrico-cámbrico (ígneo, cámbrico (metamórfico de grado medio a alto y ordovícico (metamórfico de grado medio a alto. Estas fajas estarían relacionadas con el acercamiento del terreno Cuyania al margen gondwánico, antes de su emplazamiento y colisión final en el Ordovícico superior. (4 Fajas contraccionales achalianas, con cinemáticas que indican movimientos inversos con una actividad deformacional que se extendería hasta el Devónico inferior, coincidente con la amalgamación definitiva del terreno Cuyania y con el cese del magmatismo famatiniano. Posteriormente, se registra una reactivación importante o el desarrollo de nuevas fajas de deformación alrededor del límite Devónico-Carbonífero, que serían la expresión de la orogenia Chánica producida por el emplazamiento del terreno Chilenia en el margen gondwánico.Sixteen ductile shear belts recognized at Pampean

  14. Climate, rain shadow, and human-use influences on fire regimes in the eastern Sierra Nevada, California, USA

    Science.gov (United States)

    M.P. North; K.M. van de Water; S.L. Stephens; B.M. Collins

    2009-01-01

    There have been few fire history studies of eastern Sierra Nevada forests in California, USA, where a steep elevation gradient, rain shadow conditions, and forest stand isolation may produce different fire regimes than those found on the range’s western slope. We investigated historic fire regimes and potential climate influences on four forest types ranging in...

  15. Climate and hillslope degradation vary in concert; 85 ka to present, eastern Sierra Nevada, CA, USA

    Science.gov (United States)

    Madoff, Risa D.; Putkonen, Jaakko

    2016-08-01

    Degradation in the landscape results when the interactions of climate, substrate, and biota dislodge and transport sediment that is mantling landforms. Rates of degradation through time control landform stability and resiliency. Therefore, records of past degradation rates can be used to inform us on how a given landscape responded to significant changes in past climates. For example, climate has varied at many temporal scales, and some of the largest recent shifts enabled the glacial advances and retreats in time scales of 20-100 ka. Therefore, it is reasonable to expect that the rate of landscape degradation has also varied at similar time scales. However, the general hillslope diffusion equation that is commonly used to model cross-profiles of hillslopes on time scales of thousands to tens of thousands of years typically relies on a constant and optimized rate parameter to generate a model cross-profile approximating the current observed landform cross-profile. Using a time-varying diffusivity parameter, we generated three separate degradation scenarios for the Mono Basin moraine in the eastern Sierra Nevada, CA, USA, in order to assess the potential impact of varying past climates on sediment transport. We used published paleoclimate records in the study area and modern rates of surface degradation from climates that correspond broadly to those paleoclimates. The results indicate that, in this case, the climate driven and, therefore, time-dependent degradation model produces a good fit between the modeled and observed landform profiles. Results showed that, when the surface elevations of the reference case (constant optimized diffusivity) were compared through time to the surface elevations of the time-dependent model, the differences were relatively small. The largest deviation was found to occur during the Last Glacial Maximum (LGM). We found that for investigations into the geological effects of climate change in glacial and polar regions, the use of time

  16. Patrimonio arqueológico, preservación y turismo. El caso de las Sierras de Curicó (Sistema de Tandilia, Región Pampeana, Argentina

    Directory of Open Access Journals (Sweden)

    Patricia Madrid

    2014-06-01

    Full Text Available El propósito de este artículo es discutir los efectos positivos y negativos del uso de la localidad arqueológica Sierras de Curicó (partido de Olavarría, provincia de Buenos Aires, Argentina en el marco de potenciales emprendimientos turísticos. El atractivo natural de este paisaje arqueológico conformado por pinturas rupestres, estructuras de piedra, un montículo rocoso y un alero, en las serranías bajas de Tandilia, ha concitado desde hace algunos años un uso recreativo espontáneo en un área no planificada para su uso turístico. En efecto, al impacto natural creciente se suma la acción antrópica cada vez más frecuente, poniendo a la localidad arqueológica en situación de vulnerabilidad y riesgo de conservación. Esto se acentúa particularmente en el caso de las representaciones rupestres, que constituyen sectores de visibilidad regular y altamente sensibles a la atención del visitante. En este contexto, es primordial evaluar la preservación del paisaje arqueológico como un todo antes de considerar su inclusión en proyectos de desarrollo sustentable que incluyan actividades turísticas. Previo diagnóstico, se analizan las estrategias mas adecuadas para poner en valor las Sierras de Curicó como alternativas a un uso turístico convencional en el contexto de escasas o nulas posibilidades de regular medidas efectivas de protección del patrimonio local. Por último, se recomienda un plan de manejo y la no apertura del sitio al público.

  17. The Structure at Sierra Ambato, Catamarca, Argentina: A New Meteorite Impact Site?

    Science.gov (United States)

    Acevedo, R. D.; Rocca, M.; Alonso, R.; Rabassa, J.; Ponce, J. F.

    2012-09-01

    A new possible impact crater was discovered in Catamarca Province: the structure at Sierra Ambato (28º 03" 23.22” S, 66º 03" 11.06” W), located at Sierras Pampeanas (3,500 m.a.s.l). It has 1.0 km in diameter.

  18. Distrubution of the Endocrine Disruptor Nonylphenol and the Effects of Topographical Sheilding in an Eastern Sierra Nevada Mountain Drainage

    Science.gov (United States)

    Lyons, R. A.; Van de Bittner, K.; Morgan Jones, S.

    2013-12-01

    Nonylphenol is a biodegradation product of nonylphenol polyethoxylates, a pervasive compound used in many industrial processes and notably in pesticides as a surfactant. Nonylphenol has been shown to act as an endocrine disruptor at low concentrations. It causes hermaphrodism, birth defects, and high mortality in fish, frogs and other amphibians. The Sierra Nevada Mountains separate the Central Valley in the west from the high desert of Mono Country on the east side of the state of California. The Central Valley represents some of the most heavily cultivated agricultural land in the United States. San Joaquin County alone had an annual pesticide use of over 8 million pounds in 2009 according to the Pesticide Action Network, compared with 4800 pounds in Mono County the same year. Fragile alpine ecosystems in the Sierra Nevadas may be highly susceptible to the effects of endocrine disruptors like nonylphenol. The distribution of nonylphenol is affected by localized topography in a steep walled montane canyon in the Eastern Sierra Nevada Mountains, Convict Creek canyon. The concentration of nonylphenol in snow and surface water increases as the elevation in Convict Creek canyon decreases in an easterly direction from not detectable at the highest elevations to as much as .01mg/L in water and 1.8 mg/L in snow at the lowest elevations. The steep head wall of Convict Creek canyon, facing southeast, provides shielding to the higher elevation lakes from deposition of compounds and particulate matter. As a canyon becomes less steep and broader, more nonylphenol is deposited. Identifying these deposition patterns may assist in determining amphibian and fish populations that are at higher risk of negative impact from these compounds.

  19. Post-orogenic evolution of the Sierras Septentrionales and the Sierras Australes and links to the evolution of the eastern Argentina South Atlantic passive continental margin constrained by low temperature thermochronometry and 2D thermokinematic modeling

    Science.gov (United States)

    Kollenz, Sebastian; Glasmacher, Ulrich Anton; Rossello, Eduardo A.

    2013-04-01

    The eastern Argentina South Atlantic passive continental margin is distinguished by a very flat topography. Out of the so called Pampean flat two mountain ranges are arising. These mountain ranges, the Sierras Australes and the Sierras Septentrionales, are located in the State of Buenos Aires south of the capital Buenos Aires. North of the Sierras Septentrionales the Salado basin is located. The Sierras Septentrionales and the Sierras Australes are also divided by a smaller intracratonic basin. Further in the South the Colorado basin is located. The Sierras Australes is a variscian fold belt originated by strong phases of metamorphosis, but till now it is unclear by how many tectonic phases the area was influenced (Tomezzoli & Vilas, 1999). It consists of Proterozoic to Paleozoic rocks. The Sierras Septentrionales consists mainly of Precambrian crystalline rocks. The Precambrian sequences are overlain by younger Sediments (Cingolani, 2010). The aim is to understand the long-term landscape evolution of the area by quantifiying erosion- and exhumation-rates and by dating ancient rock-uplift-events. Another goal is to find out how the opening of the south atlantic took effect on this region. To fulfill this goal, thermochronological techniques, such as fission-track dating and (U-Th-Sm)/He dating has been applied to samples from the region. Because there was no low-temperature thermochronology done in this area, both techniques were applied on apatites and zircons. Furthermore, numerical modeling of the cooling history has provided the data base for the quantification of the exhumation rates. The first data-set shows clusters of different ages which can be linked to tectonic activities during late Paleozoic times. Also the thermokinematic modeling is leading to new insights of the evolution of both mountain ranges. References: Renata Nela Tomezzoli and Juan Francisco Vilas (1999): Palaeomagnetic constraints on the age of deformation of the Sierras Australes thrust and

  20. El basamento de la sierra de San Luis: Nuevas evidencias magnéticas y sus implicancias tectónicas The basement of Sierra de San Luis: New magnetic evidence and tectonic implication

    Directory of Open Access Journals (Sweden)

    CJ Chernicoff

    2003-12-01

    Full Text Available Los mapas aeromagnéticos disponibles de las sierras de San Luis y Comechingones en el sector sudoriental de las Sierras Pampeanas de Argentina, permiten examinar las características geológicas y estructurales de las unidades metamórficas e intrusivas del basamento de la región. A través de la aplicación del filtro de continuación ascendente a los datos del campo magnético total reducido al polo, se ha podido observar la configuración profunda de las distintas unidades. Entre ellas se destaca la secuencia supracortical, en parte correspondiente a la Formación San Luis, que permite reconstruir en varios sectores de la región, en algunos casos subaflorante, una importante sucesión de rocas metasedimentarias de hasta 3 km de espesor, que es interpretada como perteneciente a depósitos de una cuenca de antepaís formada con posterioridad a la orogenia pampeana, alrededor de los 530 Ma. Se caracterizan las distintas unidades metamórficas e ígneas a partir de su señal magnética, y sobre esta base se presenta una sección estructural profunda, que sirve de base para proponer la evolución tectónica del basamento de este sector de las Sierras Pampeanas. Éste registra a partir de la orogenia pampeana la instalación de un arco magmático con su respectiva cuenca de trasarco durante el Cámbrico tardío y el Ordovícico temprano, los que son cerrados y deformados durante la colisión del terreno de Cuyania en el Ordovícico medio.The available aeromagnetic maps of the Sierras de San Luis and Comechingones in the south-eastern sector of the Sierras Pampeanas of Argentina, show the geologic and structural characteristics of the metamorphic and intrusive units of the basement of the region. Through the upward continuation filter applied to the magnetic data, it is possible to view the depth to the different units. Among them it stands out the supracrustal sequence partly equivalent to the San Luis Formation, interpreted as foreland basin

  1. Integrated Kinematic Analysis of GPS and Fault Slip Data in the Eastern California Shear Zone, Walker Lane and Sierra Nevada

    Science.gov (United States)

    Hammond, W. C.; Thatcher, W.

    2001-12-01

    The Sierra Nevada (SN) microplate moves roughly N50?W with respect to North America (NA), around an Euler pole that lies in the Pacific (PA) basin to the west and south. Its motion is indicative of processes governing the deformation of the Walker Lane and Eastern California Shear Zone, accommodating east to west expansion of the Basin and Range and approximately 25% of PA/NA dextral shear. To date, estimates for the location of the SN/NA pole obtained by GPS, VLBI and geologic data differ by at least 30 degrees [e.g. Argus and Gordon, 1996; Hearn and Humphreys, 1998]. The difference between these poles may, in part, be attributable to the type of data used in the analyses. The GPS determined velocity field potentially contains artifacts of the earthquake cycle such as recoverable elastic deformation preceded by slip at depth, fault creep, and viscoelastic relaxation following earthquakes on block bounding faults. We use Global Positioning System (GPS), fault strike and slip rate data to constrain the kinematics of the eastern boundary of the Sierra Nevada (SN) microplate, and western Basin and Range province of western North America. Data include previously published GPS measurements [Bennet et al., 1998; Thatcher et al., 1999; Gan et al., 2000; Svarc et al., submitted manuscript 2001], recently collected GPS data, and recently compiled fault maps of Nevada and California that include fault strike, slip sense and slip rate estimates. GPS velocities are refined with the Quasi Observation Combination Analysis algorithm of Dong et al. From these data we constrain the spatial variation in the rate and style of deformation throughout the region, and identify components of the deformation that are relevant to interaction of the PA/NA transform margin and Basin and Range extension. Using two-dimensional viscoelastic finite elements we derive kinematic models representative of the instantaneous (GPS) time scale, in preparation for future modeling of the longer term

  2. Structure of the Alpujarrides on the southern and eastern border of the Sierra de Lújar

    Directory of Open Access Journals (Sweden)

    Tubía, J. M.

    1990-08-01

    Full Text Available The Alpujarride complex located to the South of the Sierra Nevada and extending between Motril and Adra is formed of five nappes, which in ascending order are: Lújar, Cástaras, Alcázar, Murtas and Adra. These five nappes display a structure that is the result of several overlapping events. Firstly, they reflect a process of ductile shearing associated with a mylonitic foliation and a mylonitic lineation with a N4üo E average orientation. Following this, an episode of translation towards the North has been recorded; this occurred under more superficial conditions and developed gouges and fault breccias. Associated with this episode are locally developed folds, which did not give rise to a mineral blastesis. Afterwards, the late deformations occurred, affecting the whole ofthe ensemble. Of these, the most important are those that originated folds with a N-S axis, verging towards the West and the normal faults. The extensional faults towards the South would be encompassed in this sectionEl Complejo Alpujárride situado al Sur de Sierra Nevada y comprendido entre Motril y Adra, está formado por cinco mantos que son, en orden ascendente: Lújar, Cástaras, Alcázar, Murtas y Adra. Estos cinco mantos presentan una estructuración que es el resultado de varios acontecimientos superpuestos. En primer lugar, reflejan un proceso de cizallamiento dúctil hacia el NE, que lleva asociado una foliación milonítica, de orientación media N4üo E. A continuación se ha registrado un episodio de traslaciones hacia el Norte, en condiciones más superficiales, que desarrolla brechas y harinas de falla. Asociado a este episodio se desarrollan localmente pliegues, que no dan lugar a una blastesis mineral. Con posterioridad se producen las deformaciones tardías, que afectan a todo el conjunto. De ellas, las más sobresalientes son las que originan pliegues de eje N-S, vergentes al Oeste y las fallas normales. Las fallas extensionales hacia el Sur quedar

  3. Vegetation history along the eastern, desert escarpment of the Sierra San Pedro Mártir, Baja California, Mexico

    Science.gov (United States)

    Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate A.

    2011-05-01

    Plant macrofossils from 38 packrat middens spanning the last ~ 33,000 cal yr BP record vegetation between ~ 650 and 900 m elevation along the eastern escarpment of the Sierra San Pedro Mártir, northern Baja California. The middens span most of the Holocene, with a gap between ~ 4600 and 1800 cal yr BP, but coverage in the Pleistocene is uneven with a larger hiatus between 23,100 and 14,400 cal yr BP. The midden flora is relatively stable from the Pleistocene to Holocene. Exceptions include Pinus californiarum, Juniperus californica and other chaparral elements that were most abundant > 23,100 cal yr BP and declined after 14,400 cal yr BP. Despite being near the chaparral/woodland-desertscrub ecotone during glacial times, the midden assemblages reflect none of the climatic reversals evident in the glacial or marine record, and this is corroborated by a nearby semi-continuous pollen stratigraphy from lake sediments. Regular appearance of C 4 grasses and summer-flowering annuals since 13,600 cal yr BP indicates occurrence of summer rainfall equivalent to modern (JAS average of ~ 80-90 mm). This casts doubt on the claim, based on temperature proxies from marine sediments in the Guaymas Basin, that monsoonal development in the northern Gulf and Arizona was delayed until after 6200 cal yr BP.

  4. The Eastern delta-fan deposits on the Granada Basin as tectonic indicators of the Sierra Nevada uplift (Betic Cordillera, South Spain)

    Science.gov (United States)

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

    2014-05-01

    A geological mapping in detail of the Eastern sector of the Granada Basin (South Spain) reveals two different groups of Gilbert delta-fans related to the Sierra Nevada uplift. The first group, in the southern part and with a surface of 6 km2, has three major coarsening-upward sequences. They are composed of very coarse deposits, those of conglomerates, sands and silts. Progradational strata units to the basin have been observed. The dominantly fluvial facies association has locally developed shallow marine foreset deposits (partially with reef colonization) as well as topset red soils (Dabrio, et al., 1978; Braga et a., 1990; García-García, et al., 1999) . All the sequences are discordant over marine facies (calcarenites) dated over 8,26 Ma (Late Tortonian). The second group, in the northern part and with an extension of 12 km2, has similar characteristics, but some of the boulders have ostreids and lamellibranchs species which reveal their former position in a previous marine environment. The Sierra Nevada uplift caused the remobilization of these boulders, being transported by debris-flow inside the delta-fan bodies (García-García, et al., 2006). The dating of ostreids shells with Sr techniques reveals ages over 7,13, 6,61 and 5,45 Ma, from the lower to the upper delta-fan deposits, which are related to the three main sequences observed and with three major tectonic pulses during the Late Miocene. These interpretations are in agreement with apatite fision-track studies carried out in some boulders of these coarse delta-fan deposits (Clark and Dempster, 2013). They reveal a detailed record of Neogene denudation from the Sierra Nevada basement and with uplift periods between 5,45Ma- 2 Ma. The latest pulses affected the delta-fan sediments given rise to new fan systems in the Granada Basin (Alhambra Formation). The thoroughly study of the Miocene delta-fan sediments allows us to conclude that they were related to a sin-sedimentary tectonic activity linked to the

  5. Geochemistry and age relationships of metamorphosed mafic sills from Sierra de Enmedio and Sierra de Carrascoy (Eastern Betic zone, Southeastern Spain

    Directory of Open Access Journals (Sweden)

    Torres-Roldán, R. L.

    1989-12-01

    Full Text Available The presence of fairly abundant shallow-intrusive mafic bodies is a common feature of the almagride units, a recently defined group of tectonic elements of the Eastern Betic Zone whose paleogeographic and tectonic interpretation is particuIarly controversial. In this paper we focuse on the bulk geochemistry (including K/Ar data and possible age relationships of tbese rocks, and discuss them in view of their significance regarding possible tectonic framework of emplacement and subsequent crustal evolution. The analyses (49-55% SiO2 point to a derivation from tholeiitic magmas that interacted with continental crust, as indicated by enrichment in the less compatible elements, such as Ba, Rb, Th and K, whose amounts are similar to those of well known continental tholeiitic provinces. Thus, the magmatic event is inferred to have been generated in a tectonic environment comparable to that of continental rifts. Emplacement may have taken place in Upper Triassic to Middle Jurassic times, as bracketed by their intrusion within Triassic beds and one whole-rock KIAr date of 178±4 Ma from a less altered sample. Much younger analytical K/Ar ages, scattering between 41±5 and 57±2 Ma, are obtained from common samples, however, reflecting an Eocene or younger metamorphic event that caused partial recrystallisation under low-grade greenchist, to actinolite-pumpelIyite facies conditions. As compared to other mafic complexes in the Betics, the observed chemical evidence for crustal contamination makes the almagride metabasites more similar to those in the external zona (e.g. the so-calIed «opbites» than in tbe Nevado-Filábride Ensemble, thus being consistent with proposals that correlate these units with the Subbetic in the Murcia area.La frecuente presencia de cuerpos de metabasitas es una característica común de las unidades almágrides, un grupo de unidades tectónicas de la Zona Bética Oriental, de reciente definición, cuya interpretaci

  6. Barium-rich fluids and melts in a subduction environment (La Corea and Sierra del Convento mélanges, eastern Cuba)

    Science.gov (United States)

    Blanco-Quintero, Idael Francisco; Lázaro, C.; García-Casco, A.; Proenza, J. A.; Rojas-Agramonte, Y.

    2011-08-01

    Whole-rock compositions of muscovite-bearing amphibolite, trondhjemite, pegmatite and quartz-muscovite rocks from Sierra del Convento and La Corea mélanges (eastern Cuba), as well as mineralogy, record complex circulation of Ba-rich fluids and melts in the subduction environment. Partial melting of fluid-fluxed, MORB-derived amphibolite produced trondhjemite magmas that crystallized at depth, in some cases evolving into pegmatites. Qtz-Ms rocks probably crystallized from primary fluids derived from subducted sediments. All these rocks have elevated concentrations of large-ion lithophile elements, especially Ba (up to 11,810 ppm), presumably released from slab sediments by fluids and/or melts. Fluid-rock interaction produced crystallization of phengite in parental amphibolites. The phengite crystallized in all types of rocks is rich in Ba, with concentric zoning, characterized by Ba-rich cores and Ba-poor rims, indicating a compatible behaviour of Ba in the studied systems. Zoning in phengite is governed primarily by the celadonite (tschermak) exchange vector ((Mg,Fe)Si-(Al)-2), with more moderate contributions of the celsian (BaAl-(KSi)-1) and paragonite (NaK-1) exchange vectors. Late remobilization of Ba at relatively low temperature formed retrograde celsian. The compatible behaviour of Ba in the studied rocks strengthens the importance of the stability of phengite for the transfer of LIL elements from the subduction to the volcanic arc environments.

  7. The impact of land abandonment on soil erosion in the eastern Spain. The El Teularet - Sierra de Enguera experimental station contribution

    Science.gov (United States)

    Cerdà, A.; Bolí, M. B.; Novara, A.

    2009-04-01

    Land abandonment took place during the 50's and 60's in Spain. The mountainous areas were abandoned and a vegetation recovery processes developed a cover of shrubs on the fields. Most of those abandoned fields were affected by forest fire, which encouraged the recovery of Cistus albidus and Ulex parviflorus. At the Sierra de Enguera, in Eastern Spain, the vegetation cover on 30 year old abandoned fields is dense (90-100 % cover) and the soils doubled the organic matter content at 0-1 cm depth to the tillage ones. Tillage and herbicide management's results in crust covered soils. The objective of this research is to quantify the soil erosion losses on croplands (herbicide treatments) and on rangeland (30-yr after the abandonment), where the main vegetation covers was Ulex parviflorus. The study area show a 500 mm y-1 mean annual rainfall and vegetation establishment was very efficient. Runoff and sediment yield were collected form 1, 2, 4, and 16 m2 plots on Abandoned and Crop land management's plots A tipping-bucket raingauge (0,2 mm) was installed in 2003 and sediments and runoff collected after every rainfall event. The results show that water losses were one order of magnitude greater on the herbicide treated soils, meanwhile the soil erosion were 6.5 Mg ha-1 year-1 on the cropland and 0.05 Mg ha-1 year-1 on the abandoned soils. The results of 5 year measurements demonstrated that Mediterranean scrubland control the soil erosion processes after land abandonment.

  8. Cargas subcorticales en el antepaís andino y la planicie pampeana: evidencias estratigráficas, topográficas y geofísicas

    Directory of Open Access Journals (Sweden)

    F.M. Dávila

    2005-12-01

    Full Text Available En la región sur de los Andes Centrales, la generación de espacios de acomodación en el antepaís ha sido explicada mediante la influencia de cargas supracorticales (apilamiento de escamas tectónicas y de cargas litostáticas. Estudios en la región de Sierras Pampeanas sugieren un patrón de subsidencia de longitud de onda regional (>500 km, difícilmente explicada por estas cargas generalmente asociadas a subsidencias de longitud de onda corta (<300 km. Se propone que los rasgos estratigráficoestructurales, topográficos y geofísicos en la región de Sierras Pampeanas y en la cuenca Chaco-paranaense pueden ser explicados mediante deflexiones inducidas por mecanismos subcorticales ocurridos en el manto astenosférico y/o la corteza inferior, como flujos astenosféricos termo-inducidos y/o eclogitización, respectivamente. Las cargas supracorticales se habrían superpuesto al fenómeno de subsidencia regional, solapando su influencia localmente.

  9. Análisis de subsidencia de la Cuenca de las Salinas, Sierras Pampeanas occidentales Subsidence analysis of the Las Salinas Basin, western Sierras Pampeanas

    Directory of Open Access Journals (Sweden)

    Edgardo A. Azeglio

    2008-06-01

    Full Text Available En el presente trabajo se ha evaluado la subsidencia total de la cuenca de Las Salinas mediante diagramas tiempo - profundidad, considerando la subsidencia inicial, por carga y termotectónica. También se calculó la velocidad de subsidencia interválica en función del tiempo geológico. El área en estudio se ubica aproximadamente entre los paralelos 31°17´S y 32°40´S y los meridianos 66°38´W y 67°48´W en las cercanías de la localidad de Marayes, en el sitio denominado cuenca de Las Salinas. Los diagramas tiempo - profundidad permitieron relacionar cambios en la velocidad de subsidencia de la cuenca durante el proceso distensivo del Mesozoico y el actualmente compresional a la cual esta sometida, obteniéndose valores concordantes con áreas circundantes. Como resultado del análisis se encontró que la velocidad de subsidencia inicial fue de 0,0017 mm/año en el Carbonífero, la que fue aumentando lentamente hasta alcanzar los 0,00875 mm/año en el Cretácico. Este incremento disminuye sensiblemente durante el Cretácico superior, para posteriormente incrementarse abruptamente en el Terciario (0,043 mm/año. Este régimen se mantiene durante el Plioceno a Mioceno, alcanzando valores promedios de 0,269 mm/año, culminando con valores de 0,0973 mm/año. De la comparación entre ambos diagramas de subsidencia se observan distintos ritmos de sedimentación entre el sector norte y sur de la cuenca que podría ser la consecuencia de un fallamiento en el basamento. La comparación de estos valores con los obtenidos en la cuenca de Beazley indican que si bien los valores de subsidencia inicial y ritmo de sedimentación fueron similares. El inicio de la subsidencia en la cuenca de Beazley, se produjo con posterioridad (en el Triásico. La componente termotectónica en ambas cuencas es similar a pesar que el gradiente térmico normal de la zona aumenta sensiblemente en dirección sur.In the present work the total subsidence of Las Salinas basin has been evaluated trough time-depth diagrams, were the initial subsidence by load and thermotectonics were analyzed. The subsidence interval velocity was also calculated in function of the geologic time. The area under study is limited by the geographic coordinates of 31°17´ and 32°40´S latitude and 66°38´ and 67°48´W longitude, in the neighborhood of Marayes locality, in Las Salinas basin. The time-depth diagrams discriminate velocity changes of the basin subsidence rate during the extensional tectonics, and the present day dominant compressional process. The calculated results are in agreement with other regional rates. The obtained rates were: An initial subsidence velocity of 0.0017 mm/year during the Carboniferous period. This velocity had a constant and slow increase during Triassic and early Cretaceous times reaching mean values of 0.00875 mm/year in this last stage. The subsidence rate sensibly decreases during the late Cretaceous, and most part of the Tertiary. Subsequently a sudden change is observed during Pliocene - Miocene times reaching average values of 0.269 mm/year, and ending with rates of 0.0973 mm/year. The time-depth diagrams also show different subsidence rates from the northern and the southern parts of the basin, which could be the consequence of active basement faults during sedimentation. The initial subsidence and sedimentation rates were similar when these results are compared with Beazley Basin data, but the beginning of subsidence in Beazley Basin was later (Triassic time. The thermotectonic subsidences in both basins are similar, although the normal geothermal gradient of the area increases sensibly to the south.

  10. Cargas subcorticales en el antepaís andino y la planicie pampeana: evidencias estratigráficas, topográficas y geofísicas Subcrustal loads in the Andean foreland and pampean plain: stratigraphic, topographic and geophysical evidence

    Directory of Open Access Journals (Sweden)

    F.M. Dávila

    2005-12-01

    Full Text Available En la región sur de los Andes Centrales, la generación de espacios de acomodación en el antepaís ha sido explicada mediante la influencia de cargas supracorticales (apilamiento de escamas tectónicas y de cargas litostáticas. Estudios en la región de Sierras Pampeanas sugieren un patrón de subsidencia de longitud de onda regional (>500 km, difícilmente explicada por estas cargas generalmente asociadas a subsidencias de longitud de onda corta (In the Central Andes, supracrustal tectonic loading has been extensively invoked to explain retroarc flexure and foreland basin subsidence, due to stacking of tectonic slivers and amplification by sedimentary loads. However, we present surface and subsurface stratigraphic data from the Sierras Pampeanas broken foreland that suggest a long-wavelength subsidence pattern (>500 km, which is difficult to explain with upper crustal loads that are generally associated with short wavelength (< 300 km subsidence. It is proposed that stratigraphic, structural, topographic and geophysical features in the Sierras Pampeanas region and Chaco-Paranense basin can be explained by flections driven by processes occurring in the asthenosphere and/or lower crust, like thermal-driven corner mantle flow and/or eclogitization, respectively. Short-wavelength flexure (<300 km driven by various factors enhances regional subsidence features.

  11. El Granito Calasuya: un intrusivo alcalifeldespático postcolisional en el batolito de Sierra Norte-Ambargasta, Córdoba The Calasuya Granite: a postcollisional alkalifeldspar intrusive in the Sierra Norte-Ambargasta batholith, Córdoba province

    Directory of Open Access Journals (Sweden)

    Javier Elortegui Palacios

    2008-09-01

    Full Text Available La zona central del extenso batolito Sierra Norte-Ambargasta, en el bloque más oriental de las Sierras Pampeanas orientales, está representada por granitoides de arco magmático tipo I (granodioritas, monzogranitos, pórfidos dacíticos y riolíticos denominados serie La Isla - Cerro de los Burros, intruidos por cuerpos menores félsicos postcolisionales, químicamente más evolucionados (denominados unidades Puesto de Los Caminos y Cerro Baritina, todos pertenecientes al Neoproterozoico- Cámbrico inferior. Nueva información geológica y geoquímica de la región centro-oriental del mismo batolito permitió identificar un plutón de composición alcalifeldespática, denominado Granito Calasuya, el primero de esta naturaleza en el batolito. Su mineralogía distintiva la constituyen la composición albítica de la plagioclasa magmática (An The central-western portion of the extended Sierra Norte-Ambargasta batholith, in the easternmost block of the eastern Sierras Pampeanas, is largely characterized by pre-collisional I-type magmatic arc granitoids (granodiorites, monzogranites, dacite and rhyolite porphyries named La Isla - Cerro de los Burros series, and by smaller sized postcollisional felsic intrusives of higher evolved chemistry (named Puesto de los Caminos and Cerro Baritina units, all of which crystallized along the Late Proterozoic -Lower Cambrian time span. New geological and geochemical data from the central and oriental areas of the batholith allowed to identify an intrusive body of alkalifeldspar composition (the Calasuya granite, the first of its type in the batholith. Its distinctive mineralogy is highlighted by the albitic composition of magmatic plagioclase (molar An < 6 %, the high #Fe (0.97 of accessory biotite, the presence of accessory late magmatic fluorite, and the conspicuous postmagmatic albitization process. Its highly fractionated nature is shown by high SiO2 and low CaO, MgO, TiO2, MnO and Fe2O3(t contents, also

  12. Una propuesta para el monitoreo de la movilidad cortical actual en la sierra Chica de Zonda (Precordillera oriental de San Juan: mediciones de gravedad en red A proposal for monitoring the present crustal mobility in Sierra Chica de Zonda (Eastern Precordillera of San Juan: Gravity measurements in a network

    Directory of Open Access Journals (Sweden)

    S. Miranda

    2006-09-01

    Full Text Available Se detallan los requerimientos para el procedimiento de medición de redes precisas de gravedad que permitan obtener una interpretación de los cambios temporales de gravedad observados con relación a movimientos verticales en la corteza. Para Argentina, esta es la primera medición de gravedad en red realizada con fines de monitoreo cortical a escala local. Los vértices de la red prácticamente rodean a la sierra Chica de Zonda (Precordillera Oriental de San Juan caracterizada como una región de fallamiento activo. El objetivo científico del experimento es el ensayo de esta herramienta geofísica para cuantificar probables deformaciones verticales y/o cambios de masas subsuperficiales vinculados con actividad sísmica.In an attempt to obtain an interpretation of the observed temporal gravity changes related to crustal vertical motions, we describe a methodology using accurate gravity measurements within a fixed network. In Argentina, this is the first gravity survey measured in a network configuration for crustal monitoring studies at a local scale. The network contains the Sierra Chica de Zonda (San Juan Eastern Precordillera, a region of active tectonics. The main goal is to test a geophysical tool useful to quantify probable vertical ground deformations and/or subsurface mass changes associated with seismic activity.

  13. Geomorphic analysis of the Sierra Cabrera, an active pop-up in the constrictional domain of conjugate strike-slip faults: The Palomares and Polopos fault zones (eastern Betics, SE Spain)

    Science.gov (United States)

    Giaconia, Flavio; Booth-Rea, G.; Martínez-Martínez, J. M.; Azañón, J. M.; Pérez-Peña, J. V.

    2012-12-01

    The NNE-SSW sinistral Palomares and the conjugate dextral WNW-ESE striking Polopos fault zones terminate in the Sierra Cabrera antiform. In order to test the Quaternary activity and topographic relief control in the termination of these fault zones, here we present new qualitative and quantitative geomorphic analyses supported by a new structural map of the region. The main mountain fronts of the Cabrera antiform are formed by the North and South Cabrera reverse faults that merge laterally into the Palomares and Polopos faults, respectively. These faults produce knickpoints, stream deflections, complex basin hypsometric curves, high SLk anomalies and highly eroded basins in their proximity. Furthermore, the drainage network shows an S-shaped pattern reflecting progressive anticlockwise rotation related to the sinistral Palomares fault zone. The estimated uplift rates determined by the integration between mountain front sinuosity index and valley floor width to height ratio are larger than those obtained for strike-slip faults in the eastern Betics. These larger uplift rates with our geomorphic and structural dataset indicate that the topographic relief of the Sierra Cabrera antiform is controlled by reverse faults that form a pop-up structure in the constrictional domain between the larger Palomares-Polopos conjugate strike-slip faults. Existing GPS geodetic data suggest that the North and South Cabrera reverse faults probably accommodate a large part of Africa-Iberia convergence in the region.

  14. Análisis de subsidencia de la Cuenca de las Salinas, Sierras Pampeanas occidentales

    Directory of Open Access Journals (Sweden)

    Edgardo A. Azeglio

    2008-06-01

    Full Text Available En el presente trabajo se ha evaluado la subsidencia total de la cuenca de Las Salinas mediante diagramas tiempo - profundidad, considerando la subsidencia inicial, por carga y termotectónica. También se calculó la velocidad de subsidencia interválica en función del tiempo geológico. El área en estudio se ubica aproximadamente entre los paralelos 31°17´S y 32°40´S y los meridianos 66°38´W y 67°48´W en las cercanías de la localidad de Marayes, en el sitio denominado cuenca de Las Salinas. Los diagramas tiempo - profundidad permitieron relacionar cambios en la velocidad de subsidencia de la cuenca durante el proceso distensivo del Mesozoico y el actualmente compresional a la cual esta sometida, obteniéndose valores concordantes con áreas circundantes. Como resultado del análisis se encontró que la velocidad de subsidencia inicial fue de 0,0017 mm/año en el Carbonífero, la que fue aumentando lentamente hasta alcanzar los 0,00875 mm/año en el Cretácico. Este incremento disminuye sensiblemente durante el Cretácico superior, para posteriormente incrementarse abruptamente en el Terciario (0,043 mm/año. Este régimen se mantiene durante el Plioceno a Mioceno, alcanzando valores promedios de 0,269 mm/año, culminando con valores de 0,0973 mm/año. De la comparación entre ambos diagramas de subsidencia se observan distintos ritmos de sedimentación entre el sector norte y sur de la cuenca que podría ser la consecuencia de un fallamiento en el basamento. La comparación de estos valores con los obtenidos en la cuenca de Beazley indican que si bien los valores de subsidencia inicial y ritmo de sedimentación fueron similares. El inicio de la subsidencia en la cuenca de Beazley, se produjo con posterioridad (en el Triásico. La componente termotectónica en ambas cuencas es similar a pesar que el gradiente térmico normal de la zona aumenta sensiblemente en dirección sur.

  15. Geomorphic analysis of the Sierra Cabrera, an active pop-up in the constriction domain of conjugate strike-slip faults: the Palomares and Polopos fault zones (eastern Betics, SE Spain)

    Science.gov (United States)

    Giaconia, F.; Booth-Rea, G.; Martínez-Martínez, J. M.; Pérez-Peña, V.; Azañón, J. M.

    2012-04-01

    Segments of the Quaternary sinistral Carboneras and Palomares fault zones, striking NE-SW and NNE-SSW, respectively, terminate in the Sierra Cabrera antiform together with the conjugate dextral WNW-ESE striking Polopos fault zone. In the constriction domain between these fault zones a pop-up structure occurs formed by the North and the South Cabrera reverse faults that bound the northern and the southern hillslopes, respectively. In order to test the Quaternary activity and relief control of these fault zones, here we present new qualitative and quantitative geomorphic analyses for the Sierra Cabrera using the following indices: mountain-front sinuosity, valley floor width-to-height ratio, drainage basin asymmetry factor, basin hypsometric curve and integral, and the SLk index. These analyses were performed with the aid of several maps such as the SLk and the minimum bulk erosion map. Qualitative observations carried out on the drainage network highlight the existence of a Late Miocene fold-related drainage network and a following late Miocene to Plio-Quaternary fault-related one. Integrating the mountain-front sinuosity and the valley floor width-to-height ratio for each mountain front we estimated the uplift rates associated to each of them. Fault-related mountain-fronts with a N50-60°E strike have reverse kinematics and uplift rates larger than 0.5 m ky-1 (e.g. North and South Cabrera reverse faults), whereas those with N20-30°E and N90-100°E strikes show oblique strike-slip kinematics and show lower uplift rates, between 0.05 and 0.5 m ky-1 (e.g. the Palomares and the Polopos fault segments). Furthermore, these faults produce knickpoints, complex basin hypsometric curves, high SLk anomalies and highly eroded basins above the fault traces. The estimated uplift rates are larger than those obtained from other authors for strike-slip faults in the eastern Betics that range between 0.1 and 0.05 m ky-1 (e.g. Palomares and southern Carboneras strike-slip fault

  16. El basamento de la sierra de San Luis: Nuevas evidencias magnéticas y sus implicancias tectónicas

    Directory of Open Access Journals (Sweden)

    CJ Chernicoff

    2003-12-01

    Full Text Available Los mapas aeromagnéticos disponibles de las sierras de San Luis y Comechingones en el sector sudoriental de las Sierras Pampeanas de Argentina, permiten examinar las características geológicas y estructurales de las unidades metamórficas e intrusivas del basamento de la región. A través de la aplicación del filtro de continuación ascendente a los datos del campo magnético total reducido al polo, se ha podido observar la configuración profunda de las distintas unidades. Entre ellas se destaca la secuencia supracortical, en parte correspondiente a la Formación San Luis, que permite reconstruir en varios sectores de la región, en algunos casos subaflorante, una importante sucesión de rocas metasedimentarias de hasta 3 km de espesor, que es interpretada como perteneciente a depósitos de una cuenca de antepaís formada con posterioridad a la orogenia pampeana, alrededor de los 530 Ma. Se caracterizan las distintas unidades metamórficas e ígneas a partir de su señal magnética, y sobre esta base se presenta una sección estructural profunda, que sirve de base para proponer la evolución tectónica del basamento de este sector de las Sierras Pampeanas. Éste registra a partir de la orogenia pampeana la instalación de un arco magmático con su respectiva cuenca de trasarco durante el Cámbrico tardío y el Ordovícico temprano, los que son cerrados y deformados durante la colisión del terreno de Cuyania en el Ordovícico medio.

  17. Variabilidad morfológica craneofacial en el valle inferior del Rio Negro: implicaciones para el análisis de la dinámica poblacional en nordpatagonia y en el sudeste de la Región Pampeana

    Directory of Open Access Journals (Sweden)

    Pérez, Sergio Iván

    2001-01-01

    Full Text Available Recientemente se propuso, en base a distintas líneas de evidencia arqueológica y bioarqueológica, que los grupos humanos que habitaron el Sudeste de la Región Pampeana en distintos momentos del Holoceno fueron poblaciones locales pertenecientes a metapoblaciones alocrónicas, con un rango de distribución geográfica desconocido, pero que probablemente abarcó regiones vecinas como el norte de la Pampa Húmeda, Pampa Seca, Sierras Centrales y el norte de Patagonia. Con el fin de poner a prueba tales hipótesis, se diseñó una investigación orientada a establecer, en cada caso, el grado de similitud morfológica a nivel craneofacial (tamaño y forma, mediante análisis discriminante aplicado a variables Howellianas. En una primera etapa se analizaron muestras masculinas y femeninas provenientes del valle inferior del Río Negro (colección del Museo de La Plata; n= 133, de cronología desconocida, y muestras diacrónicas del Sudeste de la Región Pampeana, con cronología determinada radiocarbónicamente (n= 36. Los resultados preliminares muestran que: a gran parte de la variabilidad registrada en la muestra de Río Negro tiene su correlato en la registrada en la Región Pampeana, lo que sugiere una estrecha relación biológica entre los habitantes prehispánicos de estas dos regiones, y b la muestra del valle del Río Negro está probablemente integrada por individuos correspondientes a distintos momentos del Holoceno.

  18. GPS Imaging of Sierra Nevada Uplift

    Science.gov (United States)

    Hammond, W. C.; Blewitt, G.; Kreemer, C.

    2015-12-01

    Recent improvements in the scope and precision of GPS networks across California and Nevada have allowed for uplift of the Sierra Nevada to be observed directly. Much of the signal, in the range of 1 to 2 mm/yr, has been attributed to lithospheric scale rebound following massive groundwater withdrawal in the San Joaquin Valley in southern California, exacerbated by drought since 2011. However, natural tectonic deformation associated with long term uplift of the range may also contribute to the observed signal. We have developed new algorithms that enhance the signal of Sierra Nevada uplift and improve our ability to interpret and separate natural tectonic signals from anthropogenic contributions. We apply our new Median Interannual Difference Adjusted for Skewness (MIDAS) algorithm to the vertical times series and a inverse distance-weighted median spatial filtering and Delaunay-based interpolation to despeckle the rate map. The resulting spatially continuous vertical rate field is insensitive to outliers and steps in the GPS time series, and omits isolated features attributable to unstable stations or unrepresentative rates. The resulting vertical rate field for California and Nevada exhibits regionally coherent signals from the earthquake cycle including interseismic strain accumulation in Cascadia, postseismic relaxation of the mantle from recent large earthquakes in central Nevada and southern California, groundwater loading changes, and tectonic uplift of the Sierra Nevada and Coast Ranges. Uplift of the Sierra Nevada extends from the Garlock Fault in the south to an indefinite boundary in the north near the latitude of Mt. Lassen to the eastern Sierra Nevada range front in Owen's Valley. The rates transition to near zero in the southern Walker Lane. The eastern boundary of uplift coincides with the highest strain rates in the western Great Basin, suggesting higher normal fault slip rates and a component of tectonic uplift of the Sierra Nevada.

  19. Refolding of thin-skinned thrust sheets by active basement-involved thrust faults in the Eastern Precordillera of western Argentina Replegamiento de láminas de corrimiento epidérmicas mediante fallas inversas de basamento activas en la Precordillera Oriental del oeste de Argentina

    Directory of Open Access Journals (Sweden)

    A. Meigs

    2006-12-01

    Full Text Available Devastating earthquakes like the 1944 San Juan earthquake reflect active deformation in western Argentina. Although the earthquake caused considerable damage to San Juan, the source of the earthquake remains uncertain. Potential source faults occur in the thin-skinned fold-and-thrust belt Precordillera province and in the thick-skinned Sierras Pampeanas province, to the west and east, respectively of Sierra de Villicum, a thrust sheet in the eastern Precordillera northwest of San Juan. Sierra de Villicum is a west-vergent thrust sheet bound on the northwest by the Villicum thrust, which juxtaposes a southeast dipping panel of Cambro-Ordovician and Neogene strata in the hanging wall with Neogene red beds in the footwall. A series of Late Pleistocene fluvial terraces developed across the Villicum thrust show no evidence of active fold or fault deformation. Terraces are deformed by active folds and faults in the middle of the southeastern flank of the Sierra de Villicum thrust sheet. A southeast-facing, southwest-plunging monocline characterizes the Neogene red beds in the region of active folding. Co- and post-seismic surface rupture along roughly 6 km of the La Laja fault in 1944 occurred in the limb of the monocline. Evidence that surface deformation in the 1944 earthquake was dominated by folding includes terrace´s fold geometry, which is consistent with kink-band models for fold growth, and bedding-fault relationships that indicate that the La Laja fault is a flexural slip fault. A blind basement reverse fault model for the earthquake source and for active deformation reconciles the zone of terrace deformation, coseismic surface rupture on the La Laja fault, refolding of the Villicum thrust sheet, a basement arch between the Precordillera and eastern Precordillera, and microseismicity that extends northwestward from a depth of ~5 km beneath Sierra de Villicum to ~35 km depth. Maximum horizontal shortening rate is estimated to be ~3.0 mmyr-1

  20. La susceptibilidad magnética del batolito de Achala (Devónico, Sierra Grande de Córdoba) y sus diferencias con otros granitos achalianos

    OpenAIRE

    Silvana E. Geuna; Leonardo D. Escosteguy; Roberto Miró; Juan Carlos Candiani; María Fernanda Gaido

    2008-01-01

    El magmatismo devónico de las Sierras Pampeanas de Córdoba y San Luis está representado por batolitos y plutones de composición monzogranítica y forma subelíptica, emplazados en un basamento metamórfico-plutónico eopaleozoico. Se distinguen dos grupos: el primero, compuesto por granitoides con hornblenda-biotita, metaluminosos a débilmente peraluminosos; y el segundo, formado por granitoides con biotita y muscovita, peraluminosos. Ambos grupos se caracterizan respectivamente por tener magneti...

  1. Guide to Using Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Ryan Phillip; Agelastos, Anthony Michael; Miller, Joel D.

    2017-04-01

    Sierra is an engineering mechanics simulation code suite supporting the Nation's Nuclear Weapons mission as well as other customers. It has explicit ties to Sandia National Labs' workfow, including geometry and meshing, design and optimization, and visualization. Dis- tinguishing strengths include "application aware" development, scalability, SQA and V&V, multiple scales, and multi-physics coupling. This document is intended to help new and existing users of Sierra as a user manual and troubleshooting guide.

  2. Guide to Using Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Ryan Phillip [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Agelastos, Anthony Michael [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Miller, Joel D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Sierra is an engineering mechanics simulation code suite supporting the Nation's Nuclear Weapons mission as well as other customers. It has explicit ties to Sandia National Labs' workfow, including geometry and meshing, design and optimization, and visualization. Dis- tinguishing strengths include "application aware" development, scalability, SQA and V&V, multiple scales, and multi-physics coupling. This document is intended to help new and existing users of Sierra as a user manual and troubleshooting guide.

  3. La susceptibilidad magnética del batolito de Achala (Devónico, Sierra Grande de Córdoba) y sus diferencias con otros granitos achalianos The magnetic susceptibility of the Achala Batholith (Devonian, Sierra Grande de Córdoba) and its difference with other Achalian granites

    OpenAIRE

    Silvana E. Geuna; Leonardo D. Escosteguy; Roberto Miró; Juan Carlos Candiani; María Fernanda Gaido

    2008-01-01

    El magmatismo devónico de las Sierras Pampeanas de Córdoba y San Luis está representado por batolitos y plutones de composición monzogranítica y forma subelíptica, emplazados en un basamento metamórfico-plutónico eopaleozoico. Se distinguen dos grupos: el primero, compuesto por granitoides con hornblenda-biotita, metaluminosos a débilmente peraluminosos; y el segundo, formado por granitoides con biotita y muscovita, peraluminosos. Ambos grupos se caracterizan respectivamente por tener magneti...

  4. La Formación Balbuena, integrante del arco magmático pampeano en la sierra de Ambargasta, provincia de Santiago del Estero The Balbuena Formation, integrant of the Pampean magmatic arc in the Sierra de Ambargasta, Province of Santiago del Estero

    Directory of Open Access Journals (Sweden)

    M Koukharsky

    2003-12-01

    Full Text Available En un sector de las Sierras Pampeanas Orientales (29°25´ - 29°35´S y 63°43´ - 64°00´O, se estudió un conjunto de diques de acimutes entre 90 y 120° y espesores inferiores a los 10 m, que se incluyen en la Formación Balbuena. Sus composiciones abarcan dacitas, andesitas y andesitas basálticas y son interpretados como los representantes intermedios y básicos de una serie calcoalcalina cuyo extremo ácido se encontraría en los ya conocidos Pórfiros riodacíticos de Oncán aflorantes en el borde occidental del área. Son finamente porfíricos y se caracterizan por una intensa alteración de los componentes máficos y pastas, resultante de una importante actividad deutérica. Intruyen a los granitoides de las Formaciones Ojo de Agua y Ambargasta, ambos del Cámbrico medio a superior según determinaciones isotópicas. Sobre la base de edades K/Ar preexistentes, a las que se añaden dos nuevos valores, sumadas a observaciones de campo, se asignan los diques a un mismo ciclo magmático plutónico-volcánico, confirmando la vinculación ya aceptada en investigaciones anteriores para las volcanitas ácidas. Su signatura geoquímica apoya la existencia de un arco previamente postulado por otros autores y corresponden a una ubicación de arco a retroarco. Se habría desarrollado sobre corteza continental. La Formación Balbuena pertenecería al último de los eventos magmáticos importantes del ciclo Pampeano propuestos para la región.A set of dikes in the Eastern Sierras Pampeanas (29°25´ - 29°35´S y 63°43´ - 64°00´W trending from 90° to 120° azimuths and with thickness less than 10 m wide are assigned to the Balbuena Formation. These dikes are basaltic, andesitic to dacitic in composition representing basic to intermediate members of the calc-alkaline magmas that gave rise to the rhyodacitic Oncán Porphyries. The fine porphyritic rocks of the Balbuena Formation have an intense alteration of the mafic minerals and groundmass

  5. Hallazgo de espeleotemas silíceas en rocas graníticas del batolito de Achala, Sierras Pampeanas de Córdoba Occurrence of silica speothems in granitic rocks of the Achala batholith, Sierras Pampeanas of Córdoba

    Directory of Open Access Journals (Sweden)

    Marcela A. Cioccale

    2008-09-01

    Full Text Available Se presentan los primeros resultados en relación con el hallazgo de espeleotemas silíceas en rocas graníticas del batolito de Achala (Córdoba. Estas espeleotemas constituyen formas de acumulación en un ambiente dominado por procesos erosivos; alcanzando un desarrollo de unos de pocos milímetros hasta dos centímetros de espesor. Se localizan en grietas abiertas y paredes de tafonis. Presentan morfologías variadas que incluyen estalactitas y espeleotemas tipo flowstone. Están compuestas por sílice amorfa (ópalo A, yeso y fragmentos detríticos de cuarzo, feldespatos y micas. El modelado geoquímico, mediante el programa PHREEQC, permite simular la formación de estas espeleotemas a partir de procesos de evaporación del agua que circula a través de la roca fracturada.We are reporting on the occurrence of silica speleothems in granitic outcrops of the Achala batholith (Córdoba. Speleothems are accumulation forms which occur in environments dominated by erosive processes. They usually reach a thickness that varies between a few milimeters and 2 cm, and grow in fractures or in taffonis walls. Its morphology is varied and includes stalactites and flowstonetype speleothems. They are mainly composed of amorphous silica (opal-A and mineral detritus (quartz, feldspar, and mica. PHREEQC modelling allows simulating the genesis of speleothems, progressively increasing the evaporation of meteoric water that flows through fractured zones.

  6. Fuertes paleosismos de intraplaca y sus retornos vinculados a la falla Las Lagunas, Sierras Pampeanas de Cordoba Strong intraplate paleoearthquakes and their recurrence related to Las Lagunas fault, Sierras Pampeanas of Cordoba

    Directory of Open Access Journals (Sweden)

    Guillermo L Sagripanti

    2011-03-01

    Full Text Available En la intraplaca argentina, a la latitud 33°S, región sur de la provincia de Córdoba, la presencia de morfologías superficiales y deformaciones en sedimentos sueltos cuaternarios hacen suponer que la actividad tectónica neógena tuvo continuidad en el Holoceno y que seguramente fue acompañada por la ocurrencia de paleoterremotos. Los objetivos del presente trabajo son, por medio de investigaciones paleosismológicas realizar la reconstrucción del registro de la sismicidad prehistórica de la región y una estimación del potencial sismogénico de una fuente, con probada actividad cuaternaria, que sean de base en la estimación del riesgo sísmico de la región. Se excavaron seis trincheras transversales a la traza de la falla Las Lagunas, en sedimentos de origen eólico, fluvial y lagunar, en las cuales se relevaron estructuras cosísmicas, deformacionales y de licuefacción, de escala mesoscópica. Los resultados obtenidos han permitido proponer un modelo de retrodeformación para la falla, calcular el período de recurrencia de fuertes terremotos que es del orden de 1,2 - 2,0 Ka, calcular la magnitud de algunos paleo-eventos, Ms > 6,6 y hacer una estimación de la magnitud del terremoto máximo.Evidences like landforms and deformations in loose quaternary sediments, in the argentinian intraplate, at latitude 33° S, southern part of the Cordoba province, suggest that the Neogene tectonic activity continues into the Holocene and certainly had been associated to strong paleoearthquakes. The objectives of this work are to make a reconstruction of the prehistoric seis-micity record of the region by paleoseismological investigations, and to estimate the seismogenic potential of a source with proven Quaternary activity, with the aim of setting the basis to estimate the seismic risk of the region. Six trenches were dug across the trace of the Las Lagunas fault, cutting eolian, fluvial, and lagoon sediments. In the sites, several coseismic deformation and liquefaction structures were observed at a mesoscopic scale. The results allowed the proposal of a retrodeformation model for the fault, calculating the period of recurrence of strong earthquakes, around of 1,2 - 2,0 Kyr. The magnitude of some paleoevents Ms > 6,6 and maximum earthquake were also estimated.

  7. El plutón de Serrezuela: Evento magmático del Carbonífero en el sector norte de la sierra de Pocho, Córdoba, República Argentina The Serrezuela Pluton: Carboniferous magmatic event in the northerm sector of the Sierra de Pocho, Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    GM Gómez

    2003-09-01

    . El plutón de Serrezuela de edad carbonífera (321+7,4 Ma y 303+2MA, K/Ar, representa uno de los pulsos magmáticos graníticos mas jóvenes en este sector de las Sierras Pampeanas Orientales. Este cuerpo posiblemente registre el final del ciclo magmático generador de los vecinos batolito de Achala y plutón de La Playa bajo un régimen colisional.The Serrezuela granite is located at the Sierra de Serrezuela in the northern Sierra de Pocho, northwest Córdoba. It is a 16 km2 body, divided into two sectors by metamorphic outcrops. Structurally it is confined by several fractures related to major N-S regional lineaments. The Serrezuela pluton is composed of two main facies: biotite + muscovite monzogranite (BMM, and biotite tourmaline monzogranite (BTM. Both facies are calcalkaline peraluminous, with minor occurrences of a metaluminous biotite aplite. The BTM overlies the BMM facies with sharp contact, in a layer-like occurrence. The Serrezuela granitic stock is characterized by the presence of miarolitic cavities and widespread tourmalinization. A late quartz vein of considerable dimensions intrudes at the pluton boundary. Major element geochemistry shows some dispersion, whereas trace elements show a trend from biotite + muscovite monzogranite toward biotite tourmaline monzogranite. All rocks are strongly differentiated with the biotite + muscovite monzogranite being the least evolved and the most areally extended unit. A liquid fractionation mechanism is proposed for the differentiation and emplacement of the biotite tourmaline monzogranite. Changes in the foliation direction of the country rock, the presence of banded plagioclase and miarolitic cavities, suggests that the Serrezuela pluton had a forced emplacement into the country rocks at shallow crustal depth, along preexisting lineaments. Serrezuela pluton, is a Carboniferous K/Ar age granite (321± 7.4 Ma and 303± 2 Ma. It represents one of the youngest granitic magma pulses of this sector of the Eastern

  8. Fuertes paleosismos de intraplaca y sus retornos vinculados a la falla Las Lagunas, Sierras Pampeanas de Cordoba

    Directory of Open Access Journals (Sweden)

    Guillermo L Sagripanti

    2011-03-01

    Full Text Available En la intraplaca argentina, a la latitud 33°S, región sur de la provincia de Córdoba, la presencia de morfologías superficiales y deformaciones en sedimentos sueltos cuaternarios hacen suponer que la actividad tectónica neógena tuvo continuidad en el Holoceno y que seguramente fue acompañada por la ocurrencia de paleoterremotos. Los objetivos del presente trabajo son, por medio de investigaciones paleosismológicas realizar la reconstrucción del registro de la sismicidad prehistórica de la región y una estimación del potencial sismogénico de una fuente, con probada actividad cuaternaria, que sean de base en la estimación del riesgo sísmico de la región. Se excavaron seis trincheras transversales a la traza de la falla Las Lagunas, en sedimentos de origen eólico, fluvial y lagunar, en las cuales se relevaron estructuras cosísmicas, deformacionales y de licuefacción, de escala mesoscópica. Los resultados obtenidos han permitido proponer un modelo de retrodeformación para la falla, calcular el período de recurrencia de fuertes terremotos que es del orden de 1,2 - 2,0 Ka, calcular la magnitud de algunos paleo-eventos, Ms > 6,6 y hacer una estimación de la magnitud del terremoto máximo.

  9. Returnees in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Claudena Skran

    2008-12-01

    Full Text Available Over ten years of brutal civil war displaced approximately4.5 million people, about half Sierra Leone’s population.After the conflict ended in 2001, UNHCR facilitated theparticipation of both returnee refugees and returnee IDPsin community-level reconstruction projects.

  10. Control estructural sobre el plutón Los Ratones y la mineralización de uranio en la sierra de Fiambalá, Sierras Pampeanas, Catamarca

    Directory of Open Access Journals (Sweden)

    Fernando Hongn

    2010-12-01

    Full Text Available El Granito Los Ratones, de edad carbonífera, está compuesto por dos facies principales: porfírica y equigranular. La mineralización de uranio alojada en la caja metamórfica sobre el borde NO del plutón se interpreta asociada a un greisen abierto rico en flúor vinculado con las facies equigranular. La cartografía detallada de la roca de caja del plutón, de parte de los bordes del intrusivo y de las manifestaciones uraníferas muestra un marcado control estructural sobre el emplazamiento del plutón, particularmente de la facies porfírica, y sobre la circulación de los fluidos mineralizantes. Cuatro juegos de fracturas participan de este control. Los dos principales de rumbo N y NE coinciden nítidamente con los bordes oeste y noroeste de la facies porfírica y con las expresiones más notables de la mineralización de uranio. El tercer juego corresponde a fracturas de rumbo E-O que son secundarias respecto a las anteriores considerando su frecuencia y longitud, al igual que el cuarto de rumbo NO. Los buzamientos de los juegos de fracturas N y NE son próximos a la vertical, orientación corroborada por estudios geofísicos en la zona dominada por las fracturas NE. Además de los rasgos mencionados, los diques básicos y ácidos que acompañan al plutón siguen preferentemente estas orientaciones. Las estructuras que controlan el magmatismo y la mineralización estarían vinculadas con un sistema de fallas meridianas con movimiento horizontal derecho principal y normal subordinado que parcialmente reactivaron heterogeneidades del basamento metamórfico, básicamente la foliación principal. Flexiones y quiebres a lo largo de estas estructuras generaron zonas dilatantes en las que se concentraron el magmatismo y la mineralización.

  11. Sierra Structural Dynamics Theory Manual

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Garth M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-19

    Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of structural systems. This manual describes the theory behind many of the constructs in Sierra/SD. For a more detailed description of how to use Sierra/SD , we refer the reader to Sierra/SD, User's Notes . Many of the constructs in Sierra/SD are pulled directly from published material. Where possible, these materials are referenced herein. However, certain functions in Sierra/SD are specific to our implementation. We try to be far more complete in those areas. The theory manual was developed from several sources including general notes, a programmer notes manual, the user's notes and of course the material in the open literature. This page intentionally left blank.

  12. Edad y caracterización de una mica de litio asociada a un sistema de greisen en Mina la Rosario, Sierra de Fiambalá, Catamarca Age and characterization of a lithium mica associated with a greisen system in the Rosario Mine, Sierra de Fiambalá, Catamarca

    Directory of Open Access Journals (Sweden)

    Julio C. Avila

    2008-03-01

    Full Text Available En el presente trabajo se realiza el estudio mineralógico y se define la edad de una mica de litio obtenida en las salbandas de las vetas cuarzo portadoras de wolframita de mina La Rosario, ubicada en las proximidades del granito Ayacucho, Sierra de Fiambalá, Sierras Pampeanas Occidentales de la provincia de Catamarca. Esta especie mineral fue identificada a través de diferentes técnicas analíticas que incluyen determinaciones por difracción de rayos X, análisis químicos y por espectrometría infrarroja. Los resultados de los estudios indican que su estructura corresponde a una zinnwaldita y su composición química permite ubicarla dentro de la serie biotita-siderofilita-zinnwaldita-lepidolita. Las edades isotópicas obtenidas para el Granito Ayacucho (340 ± 8 Ma y esta mica hidrotermal (339 ± 8 Ma confirman una edad carbonífera para este intrusivo y la estrecha relación temporal con la mineralización hidrotermal asociada.This work deals with a mineralogical study and the age of a lithium mica obtained from the selvage of wolframite quartz veins from La Rosario mine, which crops out close to Ayacucho Granite, Sierra de Fiambalá, Sierras Pampeanas Occidentales of Catamarca province. This mineral species was identified through different analytical techniques that include X-ray diffraction, chemical analyses and infrared spectrometry analyses. The results of the studies indicate that its structure corresponds to zinnwaldite and its chemical composition allows locating it inside the biotite-siderophyllite-zinnwaldite-lepidolite series. The isotopic ages obtained for the Ayacucho granite (340 ± 8 Ma and this hydrothermal mica (339 ± 8 Ma confirm a Carboniferous age for this intrusive and the genetic link with hydrothermal mineralization.

  13. Area Handbook for Sierra Leone,

    Science.gov (United States)

    1976-01-01

    During its fifteen years of independence since 1961, Sierra Leone has had some difficulty in maintaining political stability and in generating...performance has been comparatively weak. By the mid-1970s, however, there were indications that it might improve. The Area Handbook for Sierra Leone

  14. The impact of agriculture terraces on soil organic matter, aggregate stability, water repellency and bulk density. A study in abandoned and active farms in the Sierra de Enguera, Eastern Spain.

    Science.gov (United States)

    Cerdà, Artemi; Burguet, Maria; Keesstra, Saskia; Prosdocimi, Massimo; Di Prima, Simone; Brevik, Erik; Novara, Agata; Jordan, Antonio; Tarolli, Paolo

    2016-04-01

    Soil erosion, land degradation, lack of organic matter, erodible soils, rock outcrops… are a consequence of the human abuse and misuse of the soil resources. And this is a worldwide environmental issue (Novara et al., 2011; Vanlauwe et al., 2015; Musinguzi et al., 2015; Pereira et al., 2015; Mwagno et al., 2016). Agriculture terraces are a strategy to reduce the soil erosion, improve the soil fertility and allow the ploughing (Cerdà et al., 2010; Li et al., 2014). Although this idea is well accepted there are few scientific evidences that demonstrate that soils in the terraced areas are more stable, fertile and sustainable that the soil in non terraced areas. In fact, the ploughing in comparison to the abandoned or not ploughed land results in the soil degradation (Lieskovský and Kenderessy, 2014; Gao et al., 2015; Parras-Alcántara et al., 2014). This is mainly due to the lack of vegetation that increase the surface runoff (Cerdà et al., 1998; Keesstra et al., 2007). And why is necessary to develop also in terraced landscapes soil erosion control strategies (Mekonnen et al., 2015a; Mekonnen et al., 2015b; Prosdocimi et al., 2016). Our objective was to assess the soil organic matter content (Walkley and Black, 1934), the soil bulk density (ring method), the aggregate stabilility (drop impact) and the water repellency (Water Drop Penetration Time test) in four study sites in the Sierra de Enguera. Two sites were terraced: one abandoned 40 years before the measurements and the other still active with olive crops. And two control sites non-terraced. We used the paired plot strategy to compare the impact of terracing and abandonment. At each site we collected randomly 50 soil samples at 0-2 cm, 4-6 and 8-10 cm depth. At each sampling point 100 WDPT measurements where carried out, and one sample for the bulk density, and one for the organic matter, and one for the soil aggregate stability were collected. The soil surface samples shown the largest differences. The

  15. Primer registro fehaciente de Nopachtus coagmentatus (Xenarthra, Cingulata, Glyptodontidae en la región Pampeana, Argentina. Contexto estratigráfico

    Directory of Open Access Journals (Sweden)

    Zamorano, M.

    2015-06-01

    Full Text Available The species Nopachtus coagmentatus was recognized by Amegino in 1888, on the basis of sections of the caudal tube and the dorsal carapace. These remains comes from Valles de las Sierras de Córdoba near Villa Cura Brochero, and stratigraphically from the Brochero Formation (Montehermosan-Chapadmalalan [early Pliocene - late Pliocene]. Ameghino also mentioned N. coagmentatus for the Monte Hermoso Formation (Montehermosan, but the determination Ameghino is highly questionable. The exploitation of Precambrian rocks from the center of the Sierras Bayas in Olavarría (Buenos Aires province allowed the identification from the bottom to the top, of La Alcancía Formation (Miocene, El Polvorín Formation (Pliocene, La Esperanza Formation and El Búho Formation (both late Pleistocene. In this contribution present osteoderms of the latero-dorsal portion of the posterior region of the dorsal carapace of N. coagmentatus. The specimen was extracted from brownish sandy-silt sediments of La Alcancía Quarry (36°58′40′′.06 S; 60°12′23′′.92 W corresponding to El Polvorín Formation (Upper Chapadmalalan and correspond to the first reliable record of N. coagmentatus for the Pampean region. Finally, we offer a detailed description of the specimen, and its geographic and stratigraphic provenance.La especie Nopachtus coagmentatus fue reconocida por Ameghino en 1888, basándose en porciones del tubo caudal y la coraza dorsal; estos restos proceden de los Valles de las Sierras de Córdoba, en las cercanías de Villa Cura Brochero; y, estratigráficamente, de la Formación Brochero (Montehermosense - Chapadmalalense [Plioceno temprano - Plioceno tardío]. Ameghino también la menciona para la Formación Monte Hermoso (Montehermosense, pero la determinación es altamente dudosa. La explotación de rocas precámbricas en el núcleo central de las Sierras Bayas de Olavarría (provincia Buenos Aires posibilitó el reconocimiento de la Formación El Polvor

  16. Ignimbritas riolíticas neoproterozoicas en la Sierra Norte de Córdoba: ¿evidencia de un arco magmático temprano en el ciclo Pampeano? Neoproterozoic rhyolite ignimbrites in the Sierra Norte de Córdoba: evidence of an early magmatic arc in the Pampean cycle?

    Directory of Open Access Journals (Sweden)

    EJ Llambías

    2003-12-01

    Full Text Available La Sierra Norte forma parte de las Sierras Pampeanas de Córdoba por lo cual las principales intrusiones graníticas y el metamorfismo están relacionadas al ciclo orogénico Pampeano. La mayor diferencia con las Sierras de Córdoba es que en Sierra Norte el grado metamórfico es bajo y las intrusiones son superficiales. La Sierra Norte está compuesta por pequeños afloramientos de metasedimentitas, plutones de granodiorita y granito y cuerpos subvolcánicos relacionados a los últimos estadios del batolito. En este trabajo describimos mantos de ignimbritas intercalados en los metaconglomerados de la Formación La Lidia. Las ignimbritas están moderadamente soldadas y está compuestas por aproximadamente 15 % de porfiroclastos de cuarzo, feldespato potásico y plagioclasa totalmente alterada. La pasta consiste de trizas vítreas devitrificadas. La edad U/Pb convencional en circones dio 584+22/-14 Ma y es interpretada como la edad de cristalización. Tanto las ignimbritas como la roca de caja han sido afectadas por un metamorfismo en facies prehnita-pumpellita que alteró la plagioclasa en zoicita, sericita y pumpellita. Las ignimbritas silícicas neoproterozoicas, conjuntamente con el batolito calcoalcalino que le suceden sugiere la existencia de un arco magmático asociado al margen continental activo de Gondwana. Este arco habría estado activo desde el Neoproterozoico hasta el Cámbrico, con una duración de más de 60 Ma. La correlación de las metasedimentitas y volcanitas neoproterozoicas con la Formación Puncoviscana es posible.The Sierra Norte belongs to the Sierras Pampeanas of Córdoba and like in the Sierras de Córdoba the main granitic intrusions, metamorphism and deformation are related to the Pampean orogenic cycle. The most important difference with Sierras de Córdoba is that Sierra Norte shows a weaker deformation and a lower grade metamorphism. Sierra Norte consists of small outcrops of metasedimentary rocks intruded by

  17. Sierra Nevada Subregional Boundary - Sierra Nevada Conservancy [ds542

    Data.gov (United States)

    California Department of Resources — Sierra Nevada Conservancy (SNC) boundary. The boundary was mapped to correspond with statute AB 2600 (2004) and as re-defined in AB 1201 (2005). Work on the boundary...

  18. Estimación de la estructura cortical de velocidades sísmicas en el suroeste de la sierra de Pie de Palo, provincia de San Juan Estimation of the seismic velocity crustal structure in the southwest region of the Sierra de Pie de Palo southwest San Juan

    Directory of Open Access Journals (Sweden)

    Marcelo Perarnau

    2010-12-01

    Full Text Available En este trabajo se muestran resultados relacionados con la estructura de corteza en la región de la sierra de Pie de Palo perteneciente a las Sierras Pampeanas Occidentales a partir de funciones del receptor telesísmicas para la estación sismológica Coronel Fontana (31,605°S y 68,238°O. Estos resultados ponen de manifiesto evidencias de dos discontinuidades intracorticales a profundidades de 13 y 28 km aproximadamente y una discontinuidad más profunda cerca de 47 km de profundidad que correspondería al Moho. Los valores de contraste entre las velocidades de ondas P y S (Vp/Vs para estas discontinuidades son en general elevados. En particular, la región comprendida entre 13 y 28 km de profundidad muestra los valores más altos de Vp/Vs lo cual indicaría un mayor grado de fracturación o fallamiento para esta zona de la corteza. Los resultados indican una densificación de la corteza inferior.In this paper receiver function results beneath the seismic station Coronel Fontana (31,605°S and 68,238°W, in the western Sierras Pampeanas are shown. These results provide evidence for two intracrustal discontinuities at depths of 13 km and 28 km approximately and a deeper discontinuity near 47 km depth, which correlates with the Moho. Overall the ratio between the seismic velocities of P and S waves (Vp/Vs for these discontinuities are high. In particular, the region between 13 and 28 km depth shows the higher values of Vp/Vs, which is consistent with a higher degree of fracturing and faulting. The results also indicate a denser composition of the lower crust.

  19. Sierra Nevada (Granada, Spain)

    DEFF Research Database (Denmark)

    Gilgado, José D.; Enghoff, Henrik; Tinaut, Alberto;

    2015-01-01

    Millipedes (Diplopoda), with a few notable exceptions, are poor dispersers, showing a very high degree of endemicity, not the least in mountains. The first samplings of the Mesovoid Shallow Substratum (MSS) of the higher altitudes of the Sierra Nevada Mountains (Baetic System, Southern Spain) have...... of Ceratosphys cryodeserti Gilgado, Mauriès & Enghoff n. sp. are here provided, as well as the first data on the humidity and temperature fluctuations in the MSS of this high mountain. The new species is similar to other Baetico-Riffan species, while the only previously known congener from the region, C...... led to the discovery of a high number of millipedes, each of the species present showing a different degree of establishment in this subterranean environment. An update of the knowledge on the millipedes of this region, the first data of the millipede communities in the MSS and the description...

  20. African Journals Online: Sierra Leone

    African Journals Online (AJOL)

    The Sierra Leone Journal of Biomedical Research publishes papers in all fields of ... and Allied Health Sciences including Basic Medical Sciences, Clinical Sciences, Dental Sciences, Behavioural Sciences, Biomedical Engineering, Molecular ...

  1. Nuevos aportes a la historia natural de la mulita pampeana Dasypus hybridus (Mammalia, Dasypodidae

    Directory of Open Access Journals (Sweden)

    Agustín M. Abba

    2011-12-01

    Full Text Available En este trabajo se presentan nuevos aportes sobre la historia natural de la mulita pampeana Dasypus hybridus (Desmarest, 1804 (Mammalia, Xenarthra, Dasypodidae. Los estudios de campo fueron llevados a cabo en 100 ha de cuatro establecimientos agropecuarios de la provincia de Buenos Aires, Argentina. Durante tres años se realizó un muestreo estacional de armadillos por captura y liberación. Se obtuvieron datos de hábitos alimentarios, uso del espacio y del tiempo, comportamiento, termorregulación, datos poblacionales y morfológicos. Se realizaron 71 capturas. En la dieta el ítem principal registrado fue material vegetal, seguido por hormigas e insectos coleópteros; no se observó una diferencia estacional en los hábitos alimentarios. La actividad de las mulitas se concentra durante el día, existió una baja en la frecuencia de observación durante las estaciones frías (otoño e invierno. La mulita pampeana prefiere suelos húmicos, terrenos altos y pastizales densos y altos; asimismo seleccionan los montes para refugiarse. Son individuos asociales. La temperatura rectal mostró correlaciones positivas con la temperatura ambiente. La proporción de sexos fue cercana a uno y no se observó dimorfismo sexual. Los resultados obtenidos concuerdan parcialmente con lo observado para otras especies del género, destacando las tendencias observadas en los hábitos alimentarios y en la estrategia termorregulatoria. Este trabajo representa un aporte en varios aspectos de una especie poco estudiada en una zona bajo importantes presiones de uso y modificación de hábitat.

  2. Geotermobarometría de la paragénesis cuarzo-plagioclasa-biotita- granate-sillimanita en gneises del sector centro-oriental de la sierra de Comechingones, Córdoba Geothermobarometry of Qtz + Pl + Bt + Grt + Sil paragenesis in high-grade gneisses from central-eastern portion of Sierra de Comechingones

    Directory of Open Access Journals (Sweden)

    A. B. Guereschi

    2002-12-01

    Full Text Available El basamento metamórfico del sector centro oriental de la Sierra de Comechingones (Córdoba está compuesto principalmente por gneises biotíticos granatíferos, migmatitas estromatíticas y diatexitas. Durante el pico metamórfico regional M2-D2 se habrían alcanzado condiciones de alto grado, que produjeron fusión parcial en metapelitas y desarrollaron la foliación metamórfica S2. Para determinar las condiciones de presión y temperatura imperantes en la región durante el pico metamórfico M2, se seleccionaron muestras de gneises biotíticos granatíferos, en las que se analizaron por microsonda las fases minerales principales. El geotermómetro granate-biotita y el geobarómetro granate-plagioclasa-silicato de aluminio-cuarzo (GASP, complementado con el barómetro granate-rutilo-silicato de aluminio-ilmenita-cuarzo (GRAIL, fueron aplicados a la paragénesis Qtz + Pl + Bt + Grt + Sil. Los granates exhiben grados variables de resorción, con bordes engolfados y contornos cristalinos irregulares. La resorción retrógrada parcial es corroborada por los perfiles de granate, los que muestran fuerte enriquecimiento en Fe y menor en Mn hacia los bordes. Para termobarometría fueron elegidos puntos de granate hacia adentro del borde modificado para evitar los efectos retrógrados, ya que se considera que esa es la mejor aproximación posible a las condiciones durante el pico metamórfico. Esas composiciones fueron complementadas con biotita y/o plagioclasa de la matriz para los cálculos de P-T. Los resultados termobarométricos obtenidos, 776°C de temperatura y 7,9 kb de presión, son compatibles con los equilibrios de fases minerales observados y la naturaleza migmática de gran parte del área. Estos resultados para el evento M2-D2 indican condiciones metamórficas típicamente barrovianas durante el climax de la colisión del terrane Pampia con el margen occidental de Gondwana.The metamorphic basement on the central portion of Sierra de

  3. Redescription of Trichuris pampeana (Nematoda: Trichuridae) from the South American subterranean rodent Ctenomys talarum Thomas, 1898 (Rodentia: Octodontidae).

    Science.gov (United States)

    Rossin, M Alejandra; Malizia, Ana I

    2005-02-01

    Trichuris pampeana Suriano and Navone, 1994 (Nematoda: Trichuridae) is redescribed from voucher specimens from the type host Ctenomys azarae Thomas, 1903 (Rodentia: Octodontidae) and from parasites collected from 2 populations of the subterranean rodent C. talarum Thomas, 1898 from Mar de Cobo and Necochea, Buenos Aires Province, Argentina. After a revision of these nematodes, it was confirmed that the following characters were not considered in the original description: bacillary band, cells from the esophagointestinal junction, ejaculatory duct, vas deferens, adanal papillae, vagina, oviduct, and rectum. Additional information about the spicular sheath, vulva, uteri, and ovary is provided. The morphological features given in this redescription allow to confirm the identity of T. pampeana as a valid species and also to distinguish it more clearly from other species of the genus.

  4. A seismological and petrological crustal model for the southwest of the Sierra de Pie de Palo, province of San Juan

    Directory of Open Access Journals (Sweden)

    Brígida Castro de Machuca

    2012-06-01

    Full Text Available A seismic velocity analysis from teleseismic receiver functions recorded in the southwestern fank of the Sierra de Pie de Palo (Western Sierras Pampeanas, Argentina, is compared with seismic properties directly calculated from lithological composition. The seismological results show an upper layer located in the first 13 km depth. A deeper contrast in seismic velocities is found at a depth of 28 km; the petrological results indicate a composition compatible with observed greenschist and amphibolite facies mafic rocks up to this depth. The receiver function measurements at 13 km and 28 km depths could be interpreted as two potential décollement levels that might have favoring a mechanism to thicken the whole crust, which produces a receiver function Moho signal located at 47 km depth. In addition, the lower crust between 28 km and 47 km exhibits high seismic P-wave velocities and Vp/Vs ratio (> 1.80 that are representative of a densification consistent with upper amphibolite to granulite/ecoglite facies lithologies. Based on these results, the combined petrological and seismological analyses suggest the continuation of the same mafic-crust outcropping lithologies into the lower levels of the 47-km thickened crust, which could be part of the Pie de Palo Complex ophiolite belt or the Precordillera basement.

  5. The Sierra de Mil Cumbres, Michoacán, México: Transitional volcanism between the Sierra Madre Occidental and the Trans-Mexican Volcanic Belt

    Science.gov (United States)

    Gómez-Vasconcelos, Martha Gabriela; Garduño-Monroy, Víctor Hugo; Macías, José Luis; Layer, Paul W.; Benowitz, Jeff A.

    2015-08-01

    The Sierra de Mil Cumbres is a Miocene volcanic range located in central México, in the north-eastern part of the State of Michoacán, near the city of Morelia. Structurally it is a ENE-trending horst that covers an area of 1022 km2 (approximately 20 km wide × 60 km long) and contains exposures of chemically-bimodal volcanism in the form of ignimbrites, lava domes, lava flows, cinder cones, and related deposits. The main volcanic manifestations of this range are the La Escalera Caldera (16.3-23 Ma), the Garnica Volcanic Complex (18.3-17.9 Ma), the Atécuaro Caldera (16.3-19.4 Ma), and the Indaparapeo Volcanic Complex (14.1-17.5 Ma). The Sierra de Mil Cumbres stands in space and time at the intersection between the Miocene-Recent Trans-Mexican Volcanic Belt and the Late Cretaceous-Early Miocene Sierra Madre Occidental, and so provides new insights into the geological evolution of central México. Arc volcanism in the Sierra de Mil Cumbres was initiated by a massive NNW-SSE extension, probably during the counterclockwise rotation of the Sierra Madre Occidental. New geological mapping, stratigraphic analysis, detailed geochemistry and 40Ar/39Ar geochronology demonstrates that this intra-plate volcanism was emplaced between 14 and 23 Ma.

  6. Modeling interfacial fracture in Sierra.

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Arthur A.; Ohashi, Yuki; Lu, Wei-Yang; Nelson, Stacy A. C.; Foulk, James W.,; Reedy, Earl David,; Austin, Kevin N.; Margolis, Stephen B.

    2013-09-01

    This report summarizes computational efforts to model interfacial fracture using cohesive zone models in the SIERRA/SolidMechanics (SIERRA/SM) finite element code. Cohesive surface elements were used to model crack initiation and propagation along predefined paths. Mesh convergence was observed with SIERRA/SM for numerous geometries. As the funding for this project came from the Advanced Simulation and Computing Verification and Validation (ASC V&V) focus area, considerable effort was spent performing verification and validation. Code verification was performed to compare code predictions to analytical solutions for simple three-element simulations as well as a higher-fidelity simulation of a double-cantilever beam. Parameter identification was conducted with Dakota using experimental results on asymmetric double-cantilever beam (ADCB) and end-notched-flexure (ENF) experiments conducted under Campaign-6 funding. Discretization convergence studies were also performed with respect to mesh size and time step and an optimization study was completed for mode II delamination using the ENF geometry. Throughout this verification process, numerous SIERRA/SM bugs were found and reported, all of which have been fixed, leading to over a 10-fold increase in convergence rates. Finally, mixed-mode flexure experiments were performed for validation. One of the unexplained issues encountered was material property variability for ostensibly the same composite material. Since the variability is not fully understood, it is difficult to accurately assess uncertainty when performing predictions.

  7. The role of tectonic deformation on rock avalanche occurrence in the Pampeanas Ranges, Argentina

    Science.gov (United States)

    Penna, Ivanna M.; Abellán, Antonio; Humair, Florian; Jaboyedoff, Michel; Daicz, Sergio; Fauqué, Luis

    2017-07-01

    Both tectonic and long-term gravitational slope deformation in several mountain settings have been shown to be key drivers of large-scale slope instability. The roles of both mechanisms are investigated in this study of the Potrero de Leyes rock avalanche, one of the largest and better preserved slope failures in the Pampeanas ranges in Argentina. This rock avalanche involved 0.25 km3 of highly fractured granitic rocks cropping out on an uplifted planation surface. The rock avalanche left a lobate deposit up to 4 km run out into the piedmont. A field survey, 3D terrestrial LIDAR, photogrammetry, and gigapixel panoramic photos allowed us to map the structures on the headscarp and on the planation surface. We observed a dense network of fractures with joints sets striking NNE-SSW, ENE-WSW, and NW-SE, respectively representing foliation, Riedel, and anti-Riedel structures that developed during the Paleozoic, as suggested by previous studies. The decrease of rock mass strength caused by tectonic fracturing, the exposure of those highly fractured rocks along a tectonically active mountain front, and potential deep-seated gravitational deformation occurring along NNE-SSW foliation planes along the mountain front suggest that tectonic and gravitational processes were key causal factors leading to the occurrence of the Potrero de Leyes rock avalanche.

  8. Anatomía y etnobotánica de las especies medicinales de monocotiledóneas de la Estepa Pampeana de Argentina: Poaceae

    OpenAIRE

    Ana M Arambarri; Néstor D. Bayón

    1998-01-01

    La estepa pampeana (este de la Argentina, Uruguay y sur de Río Grande do Sul, en el Brasil) posee 34 especies de Monocotiledóneas (Angiospermas) con propiedades medicinales. En el presente trabajo se ofrece el estudio de 11 especies pertenecientes a la familia Poaceae (= Gramineae). Para cada una de las especies se brindan los principales sinónimos, nombres vulgares, descripción, análisis histológico de las partes utilizadas, mapa de distribución en la estepa pampeana, ilustración y refere...

  9. Especificidade de Puccinia pampeana a cultivares de Capsicum spp. e outras solanáceas Specificity of Puccinia pampeana to Capsicum spp. cultivars and other solanaceous plants. Summa Phytopathologica

    OpenAIRE

    Martha Maria Passador; Edson Luiz Furtado; Mário Barreto Figueiredo

    2009-01-01

    A ferrugem de espécies de Capsicum spp. (pimenta e pimentão), é causada pelo fungo Puccinia pampeana, pode causar perdas totais em plantios de diversas espécies de Capsicum, onde preodminam temperaturas ao redor de 21ºC. Esta ferrugem, mesmo sendo específica do gênero Capsicum, e mesmo muitas espécies dentro deste gênero sendo suscetíveis, algumas apresentam reação de hipersensibilidade. Foi o caso de Capsicum annuum (pimenta cv. Cayenne) e C. chinense (pimenta cv. Habañero), que após a forma...

  10. Evolución tectónica andina entre las Sierras de Hualfín, capillitas y extremo sur de Aconquija, provincia de Catamarca

    Directory of Open Access Journals (Sweden)

    Raúl Seggiaro

    2014-12-01

    Full Text Available Las Sierras Pampeanas septentrionales están integradas por bloques de basamento cristalino basculados por fallas de rumbo NE-SO, que forman parte del lineamiento de Aconquija o de Tucumán. Las unidades cenozoicas, dispuestas en los valles intramontanos que separan las sierras de Capillitas, Hualfín y Aconquija, presentan relaciones de inconformidad sobre el basamento y registran cuatro sucesivos eventos deformacionales andinos. El primer evento deformacional presenta estratos de sincrecimiento asociados a fallas normales en la Formación Hualfín. Durante el segundo evento, la Formación Hualfín fue intensamente plegada y erosionada previamente a la depositación del Complejo Volcánico Farallón Negro. El tercer evento, de carácter transtensivo, se registra en el Compelo Volcánico Farallón Negro con fallas normales y discordancias progresivas. Este evento es coincidente con la irrupción del vulcanismo en la cuenca. A los fines de analizar la cinemática de la cuarta y última etapa de deformación se realizaron mediciones de indicadores cinemáticos a lo largo de fallas regionales y estructuras menores, con resultados que reflejan desplazamientos dextrales transpresivos. Los desplazamientos correspondientes a esta etapa estarían asociados a la elevación de las sierras y el emplazamiento de cuerpos subvolcánicos, algunos de los cuales como los de cerro Atajo, Capillitas y Agua Rica entre otros, son de interés económico. La tectónica transpresiva, aún vigente, se registra en fallas activas asociadas a avalanchas y flujos de detritos provenientes de las laderas de las sierras.

  11. Las metamorfitas de baja presión en la Sierra de Socoscora, San Luis, y sus implicancias regionales

    Directory of Open Access Journals (Sweden)

    Andrés Carugno Durán

    2012-06-01

    Full Text Available La secuencia metamórfica de alta temperatura y baja presión presente en la sierra de Socoscora está compuesta por esquistos con porfroblastos de cordierita y andalucita, esquistos con nódulos de sericita, esquistos cuarzo biotítico muscovíticos y anfibolitas. Todas estas rocas se encuentran en contacto tectónico con migmatitas y granitoides. Los aforamientos de esta secuencia esquistosa son saltuarios, van de unos pocos metros a algunos kilómetros cuadrados y, en algunos casos, se presentan como xenolitos en los granitoides. Esta secuencia metasedimentaria, con intercalaciones de metabasitas, presenta evidencias de al menos tres fases deformacionales (F1, F2 y F3, asociadas a una evolución metamórfica de baja presión. F1 se desarrolla conjuntamente con un metamorfismo M1 (Bt1 + Ms1, posteriormente crece cordierita estática, entre las fases F1 y F2, dando lugar a M2 (Crd + Bt2 + Qtz + Kfs, durante la fase F2 se alcanza el clímax térmico con la presencia de sillimanita (fibrolita (M3: Bt3+ Ms2 + Sil. Posteriormente, el crecimiento estático de andalucita, post F2, caracteriza a M4 (And + Ms3. Por último, durante F3 se produce el clivaje de crenulación S3. La presencia de abundantes rocas máficas y/o granitoides en la zona, podrían ser responsables de los altos gradientes que permitieron el desarrollo de las paragénesis descriptas. En otros sectores de Sierras Pampeanas se han reconocido rocas formadas en condiciones similares, asociadas a procesos asignados a las orogenias Pampeana y Famatiniana. La falta de datos geocronológicos no permite asignar con precisión las rocas estudiadas a una u otra etapa. Las rocas que se describen en este trabajo podrían corresponder a niveles de menor profundidad que los correspondientes a las migmatitas presentes en la región.

  12. Control estructural sobre el plutón Los Ratones y la mineralización de uranio en la sierra de Fiambalá, Sierras Pampeanas, Catamarca Structural control on the Los Ratones pluton and the uranium mineralization at the Fiambalá range, Sierras Pampeanas, Catamarca

    Directory of Open Access Journals (Sweden)

    Fernando Hongn

    2010-12-01

    Full Text Available El Granito Los Ratones, de edad carbonífera, está compuesto por dos facies principales: porfírica y equigranular. La mineralización de uranio alojada en la caja metamórfica sobre el borde NO del plutón se interpreta asociada a un greisen abierto rico en flúor vinculado con las facies equigranular. La cartografía detallada de la roca de caja del plutón, de parte de los bordes del intrusivo y de las manifestaciones uraníferas muestra un marcado control estructural sobre el emplazamiento del plutón, particularmente de la facies porfírica, y sobre la circulación de los fluidos mineralizantes. Cuatro juegos de fracturas participan de este control. Los dos principales de rumbo N y NE coinciden nítidamente con los bordes oeste y noroeste de la facies porfírica y con las expresiones más notables de la mineralización de uranio. El tercer juego corresponde a fracturas de rumbo E-O que son secundarias respecto a las anteriores considerando su frecuencia y longitud, al igual que el cuarto de rumbo NO. Los buzamientos de los juegos de fracturas N y NE son próximos a la vertical, orientación corroborada por estudios geofísicos en la zona dominada por las fracturas NE. Además de los rasgos mencionados, los diques básicos y ácidos que acompañan al plutón siguen preferentemente estas orientaciones. Las estructuras que controlan el magmatismo y la mineralización estarían vinculadas con un sistema de fallas meridianas con movimiento horizontal derecho principal y normal subordinado que parcialmente reactivaron heterogeneidades del basamento metamórfico, básicamente la foliación principal. Flexiones y quiebres a lo largo de estas estructuras generaron zonas dilatantes en las que se concentraron el magmatismo y la mineralización.The Carboniferous Los Ratones pluton is composed by two main facies: equigranular and porphyric. The uranium mineralization hosted by the metamorphic rock on the NW border of the pluton is related to a fluor- rich greisen related to the equigranular facies. The detailed mapping of the pluton host rock and the uranium mineralization shows a well-defined structural control on both the granite emplacement, particularly on the porphyric facies, and on the migration of the mineralized fluids. Four sets of fractures participate on this control. The two main with N and NE trends coincide clearly with the west and northwest border of the pluton as well as with the high-grade uranium manifestations. The third and fourth ones respectively corresponds to E-W and NW striking fractures, which are less developed in relation to the main fractures considering their frequency and size. Fractures of the four sets are high dipping close to vertical, attitude corroborated by geophysical studies in the area where the NE fractures are the best developed. In addition to the mentioned features, granite-related acidic and basic dikes follow mainly these orientations. The fracture sets seem to be related to a high-east dipping meridian fault system with right horizontal main movement component and subordinate normal displacement. These faults partially reactivated heterogeneities of the metamorphic rocks, mainly the dominant foliation. Changes on the strike of these fractures formed dilatant zones where magmatism and related mineralization were concentrated.

  13. East-west thrusting and anomalous magnetic declinations in the Sierra Gorda, Betic Cordillera, southern Spain

    Science.gov (United States)

    Platzman, E. S.

    1994-01-01

    Structural and palaeomagnetic studies in the Sierra Gorda (Sierra de Loja), located in the External zone of the Betic Cordillera, indicate that westward-directed thrusting is not associated with significant rotations about a vertical axis. Detailed mapping and slip vector analysis show that the Sierra Gorda is a thrust complex composed of three thrust sheets. The uppermost thrust places Early Jurassic pelagic carbonates on top of Jurassic to Oligocene sediments that form a large doubly-plunging footwall syncline. The eastern limb of this syncline has been overturned and is tectonically thinned as a result of the overthrusting. Palaeomagnetic results from Mesozoic and Tertiary sediments both within and around the perimeter of the Sierra Gorda indicate that: (1) the average remanence vector of the seven Late Jurassic localities sampled within the Sierra Gorda has a direction (D = 328° and I = 38°) that is not significantly different from the expected declination for the Upper Jurassic of stable Iberia; and (2) there is no significant difference between the remanences in the two upper thrust sheets indicating that differential rotation did not occur during the initiation and displacement on the thrusts. In contrast, the one Late Jurassic site that was sampled to the west of the Sierra Gorda is rotated, like the rest of the Subbetics, 60° clockwise of the reference direction. The unrotated directions obtained in the Sierra suggest, either that it has rotated in a clockwise sense concordant with the rest of the Subbetic zone and has then been backrotated, or that it has never rotated relative to stable Iberia. In the latter, simpler hypothesis the unrotated declinations may be explained in terms of orthogonal convergence along an irregular continental margin.

  14. CPAFFC Delegation Visits Sierra Leone and Cameroon

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>At the invitation of the Sierra Leone-China Friendship Association (SLCFA) and the Ministry of Territorial Administration and Decentralization of Cameroon, a 14-member CPAFFC delegation headed by Wang Daoyu, vice chairman of the Standing Committee of the Shandong Provincial People’s Congress, paid a goodwill visit to Sierra Leone and Cameroon in early December 2005. In Sierra Leone Vice President Solomon Ekuma Berewa, President of the Parliament Edmond Cowan, and Vice Foreign Minister Mohamed Kamara, and in

  15. Aspen Characteristics - Sierra State Parks [ds379

    Data.gov (United States)

    California Department of Resources — The database represents point locations and associated stand assessment data collected within aspen stands on lands administrated by the Sierra District, California...

  16. EFICIENCIA TECNICA DE LA LECHERIA PAMPEANA. FRONTERAS ESTOCASTICAS CON HETEROGENEIDAD OBSERVADA Y NO OBSERVADA

    Directory of Open Access Journals (Sweden)

    Ignacio Raúl Pace Guerrero

    2017-01-01

    Full Text Available Este trabajo tiene como objetivo medir la eficienci a técnica en establecimientos de producción de leche de la región pampeana argentina . Se emplean datos de panel, de 86 unidades productivas y de dos períodos productiv os (julio 2012-junio 2013 y julio 2014-junio 2015. Los datos provienen de encuestas realizadas por el INTA. El análisis también incorpora lluvias acumuladas por trimestres , estimadas por Tropical RainfallMeasuringMission (TRMM. La estimación de e ficiencia técnica se realiza a través de fronteras estocásticas de producción del tipo Cobb-Douglas. Con este fin, se prueban varias especificaciones alternativas, desde los modelos tradicionales como el de Pitt y Lee (1981, hasta los modelos que permite n controlan por heterogeneidad observada y no observada, propuestos por Greene (20 05a. El modelo True RyomEffects (TRE resulta ser la mejor especificaci ón, de acuerdo al criterio de AIC, para los datos disponibles. Los resultados muestran una pequeña reducción en la eficiencia técnica promedio de los tambos de la reg ión. Sin embargo, el comportamiento no es homogéneo para las diferentes provincias consideradas, donde sólo para el caso de Buenos Aires se observa un inc remento en la eficiencia técnica, pasando de ser, en promedio, los tambos menos efici entes a ser los más eficientes.

  17. Ruralidad del empleo agropecuario en la región pampeana.

    Directory of Open Access Journals (Sweden)

    Jose Luis Pellegrini

    2012-11-01

    Full Text Available En esta tesis se ofrece una explicación económica para la proporción de población ocupada en el sector agropecuario que es rural y su distribución espacial, en la región pampeana al comenzar el siglo XXI. Por rural se entiende que reside en campo abierto, de acuerdo a los criterios censales utilizados en la Argentina para definir a la población rural dispersa. Se sostiene que la ruralidad del empleo agropecuario en cada área y sus alrededores depende de la importancia relativa de la agricultura y otras producciones agropecuarias, pero también de variables menos evidentes que a la postre resultan empíricamente más relevantes: los grados de urbanización del área y riqueza de la población agraria. Se obtienen esas conclusiones mediante un análisis conceptual de los costos comparativos de organizar la transacción de trabajo agropecuario con población rural o población urbana, en tanto el lugar de residencia afecta las actividades productivas y domésticas de los trabajadores. El problema se define como de organización económica en el nivel mesoeconómico, que tiene detrás uno más elemental: el de organización de la transacción de trabajo. Metodológicamente, en el aspecto conceptual se procede de manera abstracto-deductiva a partir de una representación estilizada del problema en cuestión, y en el empírico se realiza un estudio de corte transversal con datos censales, que culmina en un análisis econométrico espacial que no rechaza las principales hipótesis específicas deducidas.

  18. El registro de la pequena edad de hielo en lagunas pampeanas

    Directory of Open Access Journals (Sweden)

    Cecilia Laprida

    2009-12-01

    Full Text Available Se conoce como Pequeña Edad de Hielo (LIA al episodio acontecido entre el siglo 16 y mediados del siglo 19, durante el cual el clima en Europa se tornó frío y ocasionalmente tormentoso. En ciertas partes de Europa, las observaciones instrumentales lo abarcan parcialmente, pero para Sudamérica no se dispone de registros instrumentales contemporáneos a dicho evento. Con el objetivo de obtener nuevas evidencias para el período comprendido por la Pequeña Edad de Hielo en la llanura pampeana, se analizaron testigos cortos de la laguna de Chascomús y de la laguna del Monte los que, de acuerdo a dataciones AMS, abarcan los últimos 500 años. Ambos testigos constan de tres secuencias granodecrecientes. El análisis del registro de la laguna de Chascomús ha permitido reconocer un período benigno desde fines del siglo 15 hasta alrededor del 1700, cuando se evidencia una retracción de la laguna que inaugura un período seco. Este episodio habría continuado por casi 150 años y se revierte alrededor de 1850, momento a partir del cual los eventos de excesos hídricos comenzaron a dominar el escenario pampeano. La base del testigo de la laguna de Monte fue datada en 1441-1494 AD. Si bien el modelo de edades para este testigo aún no ha podido ser bien establecido, los eventos de Chascomús y Monte podrían ser correlacionables y expresar tendencias seculares regionales de la humedad.

  19. Constraints on the history and topography of the Northeastern Sierra Nevada from a Neogene sedimentary basin in the Reno-Verdi area, Western Nevada

    Science.gov (United States)

    Trexler, James; Cashman, Patricia; Cosca, Michael

    2012-01-01

    Neogene (Miocene–Pliocene) sedimentary rocks of the northeastern Sierra Nevada were deposited in small basins that formed in response to volcanic and tectonic activity along the eastern margin of the Sierra. These strata record an early phase (ca. 11–10 Ma) of extension and rapid sedimentation of boulder conglomerates and debrites deposited on alluvial fans, followed by fluvio-lacustrine sedimentation and nearby volcanic arc activity but tectonic quiescence, until ~ 2.6 Ma. The fossil record in these rocks documents a warmer, wetter climate featuring large mammals and lacking the Sierran orographic rain shadow that dominates climate today on the eastern edge of the Sierra. This record of a general lack of paleo-relief across the eastern margin of the Sierra Nevada is consistent with evidence presented elsewhere that there was not a significant topographic barrier between the Pacific Ocean and the interior of the continent east of the Sierra before ~ 2.6 Ma. However, these sediments do not record an integrated drainage system either to the east into the Great Basin like the modern Truckee River, or to the west across the Sierra like the ancestral Feather and Yuba rivers. The Neogene Reno-Verdi basin was one of several, scattered endorheic (i.e., internally drained) basins occupying this part of the Cascade intra-arc and back-arc area.

  20. Eventos de avalanchas y represamientos reiterados de ocurrencia prehistórica en la cuenca del río Villavil, sierra de Aconquija, Andalgalá, Catamarca

    Directory of Open Access Journals (Sweden)

    Aldo Luis Banchig

    2009-12-01

    Full Text Available Este trabajo presenta la existencia de un cuerpo sedimentario cuyos mecanismos depositacionales involucran procesos gravitacionales de gran envergadura, identificado como una avalancha de rocas (2,69 x10(9 m³, de carácter prehistórico con reactivaciones sucesivas, generado en la ladera oriental del cerro Zapallar (3.100 m s.n.m., en el extremo sur de la sierra del Aconquija (Sierras Pampeanas. Las múltiples reactivaciones de este depósito han generado reiterados represamientos en el río Villavil. La zona de estudio se emplaza en afloramientos de rocas ígneas graníticas del basamento y en proximidades de la intersección de dos grandes fallamientos regionales que, al parecer, han influido en la generación de estos eventos. Evidencias de actividad cuaternaria de los fallamientos regionales permiten deducir una posible sismogénesis asociada a estas estructuras, aunque esto no se correlaciona con la sismicidad histórica. La ocurrencia de colapsos sucesivos asociados a la oclusión reiterada del río Villavil, representa un riesgo potencial al desarrollo de la localidad de Villavil ubicada en la misma quebrada.

  1. Stock monzogranítico El Chorro (Sierra de Ancasti, Catamarca: un ejemplo de magmatismo tipo S con granate ígneo

    Directory of Open Access Journals (Sweden)

    Juan A Dahlquist

    2011-06-01

    Full Text Available Las rocas graníticas ordovícicas de la sierra de Ancasti representan uno de los afloramientos más orientales del cinturón orogénico famatiniano de Sierras Pampeanas. Se describe un pequeño stock granítico (denominado El Chorro cuyo rasgo distintivo es la presencia de granate. Aunque el granate es un mineral accesorio poco común en rocas ígneas, su presencia es petrológicamente significativa. El Chorro es un monzogranito tipo S que contiene una inusual cantidad de granate magmático (2,8 % modal. Estudios combinados de petrología, química mineral y de geoquímica de roca total sugieren que se trata de un magma peraluminoso generado por la fusión parcial de rocas metasedimentarias, con la subsecuente formación de granate durante la cristalización. Los estudios realizados muestran que el granate cristalizó en equilibrio con otras fases minerales como biotita y muscovita. Cálculos geotermobarométricos revelan una temperatura de cristalización de 710-716 ºC y una presión de 3,8 + 0,8 kbar, indicando que el magma fue emplazado en la corteza media (~ 14 km con temperaturas de cristalización magmáticas medias a bajas.

  2. Estimación de la estructura cortical de velocidades sísmicas en el suroeste de la sierra de Pie de Palo, provincia de San Juan

    Directory of Open Access Journals (Sweden)

    Marcelo Perarnau

    2010-12-01

    Full Text Available En este trabajo se muestran resultados relacionados con la estructura de corteza en la región de la sierra de Pie de Palo perteneciente a las Sierras Pampeanas Occidentales a partir de funciones del receptor telesísmicas para la estación sismológica Coronel Fontana (31,605°S y 68,238°O. Estos resultados ponen de manifiesto evidencias de dos discontinuidades intracorticales a profundidades de 13 y 28 km aproximadamente y una discontinuidad más profunda cerca de 47 km de profundidad que correspondería al Moho. Los valores de contraste entre las velocidades de ondas P y S (Vp/Vs para estas discontinuidades son en general elevados. En particular, la región comprendida entre 13 y 28 km de profundidad muestra los valores más altos de Vp/Vs lo cual indicaría un mayor grado de fracturación o fallamiento para esta zona de la corteza. Los resultados indican una densificación de la corteza inferior.

  3. Edad y caracterización de una mica de litio asociada a un sistema de greisen en Mina la Rosario, Sierra de Fiambalá, Catamarca

    Directory of Open Access Journals (Sweden)

    Julio C. Avila

    2008-03-01

    Full Text Available En el presente trabajo se realiza el estudio mineralógico y se define la edad de una mica de litio obtenida en las salbandas de las vetas cuarzo portadoras de wolframita de mina La Rosario, ubicada en las proximidades del granito Ayacucho, Sierra de Fiambalá, Sierras Pampeanas Occidentales de la provincia de Catamarca. Esta especie mineral fue identificada a través de diferentes técnicas analíticas que incluyen determinaciones por difracción de rayos X, análisis químicos y por espectrometría infrarroja. Los resultados de los estudios indican que su estructura corresponde a una zinnwaldita y su composición química permite ubicarla dentro de la serie biotita-siderofilita-zinnwaldita-lepidolita. Las edades isotópicas obtenidas para el Granito Ayacucho (340 ± 8 Ma y esta mica hidrotermal (339 ± 8 Ma confirman una edad carbonífera para este intrusivo y la estrecha relación temporal con la mineralización hidrotermal asociada.

  4. Contribución amerindia y africana en el sur de la Región Pampeana

    Directory of Open Access Journals (Sweden)

    Avena, Sergio Alejandro

    2005-01-01

    Full Text Available En este trabajo nos propusimos estimar el aporte amerindio y africano en el sur de la Región Pampeana mediante el análisis de 6 sistemas genéticos eritrocitarios y del ADN mitocondrial. Se estudió una muestra de 181 dadores de sangre, no emparentados, que concurrieron a dos hospitales de la ciudad de Bahía Blanca. Considerando los sistemas grupales sanguíneos se registró un 24% y un 7% de componente indígena y africano, respectivamente. No se observaron haplogrupos mitocondriales de origen africano, en cambio, se detectó un 60% de linajes maternos amerindios. Esta elevada contribución indígena, sexo-específica, estaría revelando la existencia de un aporte asimétrico por género en la historia de esta población. La importante contribución indígena y en menor medida africana detectada en la muestra analizada, que coincide con lo registrado en un estudio previo realizado en la Ciudad de Buenos Aires, nos sugiere reconsiderar la idea de que la Argentina y en particular la Región Pampeana esta constituida, únicamente, por descendientes de europeos.

  5. Ignimbritas riolíticas neoproterozoicas en la Sierra Norte de Córdoba: ¿evidencia de un arco magmático temprano en el ciclo Pampeano?

    Directory of Open Access Journals (Sweden)

    EJ Llambías

    2003-12-01

    Full Text Available La Sierra Norte forma parte de las Sierras Pampeanas de Córdoba por lo cual las principales intrusiones graníticas y el metamorfismo están relacionadas al ciclo orogénico Pampeano. La mayor diferencia con las Sierras de Córdoba es que en Sierra Norte el grado metamórfico es bajo y las intrusiones son superficiales. La Sierra Norte está compuesta por pequeños afloramientos de metasedimentitas, plutones de granodiorita y granito y cuerpos subvolcánicos relacionados a los últimos estadios del batolito. En este trabajo describimos mantos de ignimbritas intercalados en los metaconglomerados de la Formación La Lidia. Las ignimbritas están moderadamente soldadas y está compuestas por aproximadamente 15 % de porfiroclastos de cuarzo, feldespato potásico y plagioclasa totalmente alterada. La pasta consiste de trizas vítreas devitrificadas. La edad U/Pb convencional en circones dio 584+22/-14 Ma y es interpretada como la edad de cristalización. Tanto las ignimbritas como la roca de caja han sido afectadas por un metamorfismo en facies prehnita-pumpellita que alteró la plagioclasa en zoicita, sericita y pumpellita. Las ignimbritas silícicas neoproterozoicas, conjuntamente con el batolito calcoalcalino que le suceden sugiere la existencia de un arco magmático asociado al margen continental activo de Gondwana. Este arco habría estado activo desde el Neoproterozoico hasta el Cámbrico, con una duración de más de 60 Ma. La correlación de las metasedimentitas y volcanitas neoproterozoicas con la Formación Puncoviscana es posible.

  6. Las Orogénesis del Paleozoico Inferior en el margen proto-andino de América del Sur, Sierras Pampeanas, Argentina

    OpenAIRE

    Rapela, Carlos W.; Casquet, César; Baldo, Edgardo G.; Juan A Dahlquist; Pankhurst, R. J.; Galindo Francisco, Mª del Carmen; Saavedra, Julio

    2001-01-01

    El margen proto-andino de Gondwana ha sido el escenario de al menos dos orogénesis desde el desmembramiento del supercontinente Rodinia al final del Neoprotrozoico, hasta el reagrupamiento de las masas continentales en Pangea al final del Carbonifero. Ambas orogénesis van precedidas de un periodo de apertura oceánica y sedimentación en márgenes pasivos y culminan en subducción oceánica con desarrollo de arcos-magmáticos de tipo cordillerano y colision de tipo continente-cont...

  7. Hallazgo de espeleotemas silíceas en rocas graníticas del batolito de Achala, Sierras Pampeanas de Córdoba

    Directory of Open Access Journals (Sweden)

    Marcela A. Cioccale

    2008-09-01

    Full Text Available Se presentan los primeros resultados en relación con el hallazgo de espeleotemas silíceas en rocas graníticas del batolito de Achala (Córdoba. Estas espeleotemas constituyen formas de acumulación en un ambiente dominado por procesos erosivos; alcanzando un desarrollo de unos de pocos milímetros hasta dos centímetros de espesor. Se localizan en grietas abiertas y paredes de tafonis. Presentan morfologías variadas que incluyen estalactitas y espeleotemas tipo flowstone. Están compuestas por sílice amorfa (ópalo A, yeso y fragmentos detríticos de cuarzo, feldespatos y micas. El modelado geoquímico, mediante el programa PHREEQC, permite simular la formación de estas espeleotemas a partir de procesos de evaporación del agua que circula a través de la roca fracturada.

  8. My Great Migration from Sierra Leone

    Science.gov (United States)

    Harvard Educational Review, 2011

    2011-01-01

    This article presents the author's personal narrative as an immigrant from Sierra Leone who has undergone so many challenges in life and ended up turning all these obstacles into opportunities. In this article, the author describes his life growing up in Sierra Leone, his first experience of the horrors of war, his life as a student, and his dream…

  9. Reading Comprehension Instruction Practices in Sierra Leone

    NARCIS (Netherlands)

    Hersbach, S.; Denessen, E.J.P.G.; Droop, W.

    2014-01-01

    Aim: In this study an attempt was made to give insight in the way reading comprehension is taught in Sierra Leone. Attention was paid to the didactical strategies and the materials used during reading comprehension instruction. Methodology: Primary school teachers in Sierra Leone (N=43) were observe

  10. Reading Comprehension Instruction Practices in Sierra Leone

    NARCIS (Netherlands)

    Hersbach, S.; Denessen, E.J.P.G.; Droop, W.

    2014-01-01

    Aim: In this study an attempt was made to give insight in the way reading comprehension is taught in Sierra Leone. Attention was paid to the didactical strategies and the materials used during reading comprehension instruction. Methodology: Primary school teachers in Sierra Leone (N=43) were

  11. Cretin Memory Flow on Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Langer, S. H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Scott, H. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-05

    The Cretin iCOE project has a goal of enabling the efficient generation of Non-LTE opacities for use in radiation-hydrodynamic simulation codes using the Nvidia boards on LLNL’s upcoming Sierra system. Achieving the desired level of accuracy for some simulations require the use of a vary large number of atomic configurations (a configuration includes the atomic level for all electrons and how they are coupled together). The NLTE rate matrix needs to be solved separately in each zone. Calculating NLTE opacities can consume more time than all other physics packages used in a simulation.

  12. Sierra/SM theory manual.

    Energy Technology Data Exchange (ETDEWEB)

    Crane, Nathan Karl

    2013-07-01

    Presented in this document are the theoretical aspects of capabilities contained in the Sierra/SM code. This manuscript serves as an ideal starting point for understanding the theoretical foundations of the code. For a comprehensive study of these capabilities, the reader is encouraged to explore the many references to scientific articles and textbooks contained in this manual. It is important to point out that some capabilities are still in development and may not be presented in this document. Further updates to this manuscript will be made as these capabilites come closer to production level.

  13. Geocronología, paleoambientes y paleosuelos holocenos en la región pampeana

    Directory of Open Access Journals (Sweden)

    E. Fucks

    2007-09-01

    Full Text Available Las condiciones paleoambientales de la región pampeana durante el Holoceno, generaron diferentes superficies de estabilización del paisaje, permitiendo la formación de suelos tanto en ambientes de la llanura marina costera como en ambientes continentales. El análisis de diferentes perfiles geológicos en cuatro localidades y sus áreas de influencia en el NE y E de la provincia de Buenos Aires, permitieron identificar eventos pedogenéticos ubicados entre circa 4.500 años AP - 3.500 años 14C AP y circa 1.700 años 14C AP, en ambientes de la llanura marina costera y eventos pedogenéticos en planicies de inundación, ubicados cronológicamente con posterioridad a los circa 8.500- 8.000 años 14C AP, finalizando 2.000 años 14C AP. La cronología radiocarbónica permitió también: 1 ubicar cronológicamente el tope de la depositación del Miembro Guerrero de la Formación Luján dentro del Holoceno temprano (circa 8.500 años 14C AP; 2 ubicar el lapso máximo de depositación del sedimento denominado aluvio actual, desde el Holoceno tardío (circa 2.500 años 14C AP hasta los depósitos actuales donde se desarrolla un suelo muy incipiente; 3 datar eventos pedogenéticos dentro del aluvio actual en circa 1.700 años 14C AP; 4 estimar el retiro del máximo transgresivo del Holoceno y el comienzo de condiciones fluviales (circa 4.500 - 4.200 años 14C AP.

  14. Contrasting magmatic structures between small plutons and batholiths emplaced at shallow crustal level (Sierras de Córdoba, Argentina)

    Science.gov (United States)

    Pinotti, Lucio P.; D'Eramo, Fernando J.; Weinberg, Roberto F.; Demartis, Manuel; Tubía, José María; Coniglio, Jorge E.; Radice, Stefania; Maffini, M. Natalia; Aragón, Eugenio

    2016-11-01

    Processes like injection, magma flow and differentiation and influence of the regional strain field are here described and contrasted to shed light on their role in the formation of small plutons and large batholiths their magmatic structures. The final geometric and compositional arrangement of magma bodies are a complex record of their construction and internal flow history. Magma injection, flow and differentiation, as well as regional stresses, all control the internal nature of magma bodies. Large magma bodies emplaced at shallow crustal levels result from the intrusion of multiple magma batches that interact in a variety of ways, depending on internal and external dynamics, and where the early magmatic, growth-related structures are commonly overprinted by subsequent history. In contrast, small plutons emplaced in the brittle-ductile transition more likely preserve growth-related structures, having a relatively simple cooling history and limited internal magma flow. Outcrop-scale magmatic structures in both cases record a rich set of complementary information that can help elucidate their evolution. Large and small granitic bodies of the Sierra Pampeanas preserve excellent exposures of magmatic structures that formed as magmas stepped through different rheological states during pluton growth and solidification. These structures reveal not only the flow pattern inside magma chambers, but also the rheological evolution of magmas in response to temperature evolution.

  15. Etnometodología para la comprensión y el manejo de la Enfermedad de Chagas en las poblaciones indígenas Wiwa asentadas en la vertiente suroriental de la Sierra Nevada de Santa Marta Ethno-methodology to comprehension and management of Chagas disease in Wiwa indigenous communities placed in south-eastern slope from Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Leonardo Alberto Ríos-Osorio

    2012-06-01

    Full Text Available El objetivo de este trabajo fue establecer prevalencia de la Enfermedad de Chagas en las comunidades Wiwa de la Sierra Nevada de Santa Marta trascendiendo el modelo de investigación biomédica sustentado en el paradigma positivista, e involucrando la dimensión sociocultural y ambiental que caracteriza este fenómeno, desde la sostenibilidad como un nuevo paradigma de las ciencias. Se realizó un muestreo probabilístico de las 15 comunidades Wiwa asentadas en la zona de San Juan del César, Departamento de la Guajira, se realizaron los procedimientos biomédicos definidos para investigaciones epidemiológicas, paralelamente se realizaron procedimientos culturales desde el saber tradicional de las comunidades Wiwa, garantizando la armonía de las comunidades ante la agresión biomédica de su espacio ambiental, social y cultural. Se obtuvo una prevalencia de 33.5%, concordante con las cifras de Enfermedad de Chagas encontradas en las otras vertientes de la sierra, reflejando condiciones similares que predisponen a la presencia de la enfermedad. Se estableció como esta enfermedad es inexistente en el sistema médico tradicional de los Wiwa, y sólo el insecto vector es reconocido aunque no considerado como agente perturbador de la salud de las comunidades. A partir de la consideración del vector como eje integrador de las dos culturas se describen las características sociales, ambientales y culturales que definen la Enfermedad de Chagas en los Wiwa y de esta forma, la posibilidad de su comprensión y manejo desde factores complementarios al modelo biomédico.The goal of this research was to establish Chagas Disease prevalence in Wiwa communities of Sierra Nevada de Santa Marta, beyond biomedical research model supported in positivist paradigm, towards sustainability as a new paradigm of science, by which this phenomenon has a social, cultural and environmental dimensions. A probabilistic sample was made it in 15 Wiwa communities placed in San

  16. SIERRA framework version 4 : solver services.

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Alan B.

    2005-02-01

    Several SIERRA applications make use of third-party libraries to solve systems of linear and nonlinear equations, and to solve eigenproblems. The classes and interfaces in the SIERRA framework that provide linear system assembly services and access to solver libraries are collectively referred to as solver services. This paper provides an overview of SIERRA's solver services including the design goals that drove the development, and relationships and interactions among the various classes. The process of assembling and manipulating linear systems will be described, as well as access to solution methods and other operations.

  17. Surface uplift and atmospheric flow deflection in the Late Cenozoic southern Sierra Nevada

    Science.gov (United States)

    Mix, H.; Caves, J. K.; Winnick, M.; Ritch, A. J.; Reilly, S.; Chamberlain, C. P.

    2016-12-01

    Given the intimate links between topography, tectonics, climate and biodiversity, considerable effort has been devoted to developing robust elevation histories of orogens. In particular, quantitative geochemical reconstructions using stable oxygen and hydrogen isotopes have been applied to many of the world's mountain belts. Yet after decades of study, determining the Cenozoic surface uplift history of the Sierra Nevada remains a challenge. While geological and geophysical evidence suggests the southern Sierra underwent 1-2 km of Late Cenozoic surface uplift, stable isotope paleoaltimetry studies to date have been restricted to the Basin and Range interior. Recent advances in atmospheric modeling have suggested that such stable isotope records from leeward sites can be affected by the complicating role that sufficiently elevated topography such as the southern (High) Sierra plays in diverting atmospheric circulation. In order to examine the potential role of these terrain blocking effects, we produced stable isotope records from three Late Cenozoic sedimentary basins in the Eastern Sierra and Basin and Range: 1) Authigenic clay minerals in the Mio-Pliocene Verdi Basin (VB), 2) Fluvial and lacustrine carbonates from the Plio-Pleistocene Coso Basin (CB), and 3) Miocene to Holocene pedogenic, fluvial and lacustrine carbonates of Fish Lake Valley (FLV). Whereas both the VB (near present-day Reno) and CB (southern Owens Valley) receive input of water directly from the Sierra crest, FLV is a region of proposed reconvergence of moisture in the Basin and Range. The oxygen isotope records in both CB and FLV increase during the Neogene by approximately 2 ‰, while the hydrogen isotope record of the VB decreases by <10 ‰. These results are consistent with a modestly-elevated Paleogene Sierra of 2 km over which air masses traversed and underwent orographic rainout and Rayleigh distillation. A Neogene pulse of uplift in the southern Sierra could have driven modern flow

  18. Sierra Leone Journal of Biomedical Research

    African Journals Online (AJOL)

    MHRL

    (A publication of the College of Medicine and Allied Health Sciences, University of Sierra Leone). Original Article ... aspects and advocated better training of ..... 2000). Their career choice ... care and its determinants in north-central Nigeria.

  19. Sierra Leone Journal of Biomedical Research

    African Journals Online (AJOL)

    The Sierra Leone Journal of Biomedical Research publishes papers in all fields of ... and Allied Health Sciences including Basic Medical Sciences, Clinical Sciences, Dental Sciences, Behavioural Sciences, Biomedical Engineering, Molecular ...

  20. Aspen Delineation - Sierra State Parks [ds380

    Data.gov (United States)

    California Department of Resources — The database represents delineations of aspen stands associated with stand assessment data (SIERRA_SP_PTS) collected in aspen stands on lands administered by the...

  1. Running Parallel Discrete Event Simulators on Sierra

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, P. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Jefferson, D. R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-12-03

    In this proposal we consider porting the ROSS/Charm++ simulator and the discrete event models that run under its control so that they run on the Sierra architecture and make efficient use of the Volta GPUs.

  2. Cholera epidemic threatens Sierra Leone.

    Science.gov (United States)

    Dyer, O

    1995-07-08

    Sierra Leone faces the threat of a major epidemic of cholera with the onset of the rainy season, according to the World Health Organization (WHO). The situation is particularly grave for the two million people displaced by the country's civil war. Already 1709 cases of cholera have been registered in Freetown, with 57 deaths. Freetown's population has doubled since the start of the war in 1991 with 750,000 refugees camping out in the town. The insurgent Revolutionary United Front is now within 32 km of the capital. Provinces are cut off from the capital, medical supplies are scarce. Doctors and aid workers are forced to rely on a private helicopter service for personal transport. As many as 10,000 people were affected by the disease last year. WHO experts predict that pneumonia is likely to claim the lives of many children, and a highly drug resistant strain of Plasmodium falciparum malaria is also looming. The greatest problems are the lack of safe drinking water and the attendant risks of cholera and dysentery. At one site in Freetown the 6000 refugees have to fetch water from a well and have no latrines. As a result there have been 277 cases of cholera and 2 deaths already among that group. The health department has set up five centers to treat cholera in Freetown and is organizing mobile clinics. WHO's Sierra Leone office is assisting the government mobile health teams, which provide free primary care to displaced people. Medicines and vaccines, however, are lacking. Many of the staff of the 13 district health authorities have been displaced to Freetown. Aid agencies such as Medecins Sans Frontieres and Oxfam have stepped into the role in many districts. Ironically, one of the Revolutionary United Front's main demands is for a free national health service.

  3. Stabilization Lessons Learned from Sierra Leone

    Science.gov (United States)

    2013-12-01

    Reduction Project (0704–0188) Washington, DC 20503. 1. AGENCY USE ONLY (Leave blank) 2. REPORT DATE December 2013 3. REPORT TYPE AND DATES...Ibid. 48 Accord Sierra Leone Project , Paying the Price: the Sierra Leone Peace Process, (Accord issue 9, 2000), London, 2000. http://www.c-r.org...continued to grow as ECOMOG was replaced by UNAMSIL at Mange and Kambia and UNAMSIL pushed out to Kabala in the North, Joru near the Liberian border

  4. Especificidade de Puccinia pampeana a cultivares de Capsicum spp. e outras solanáceas Specificity of Puccinia pampeana to Capsicum spp. cultivars and other solanaceous plants. Summa Phytopathologica

    Directory of Open Access Journals (Sweden)

    Martha Maria Passador

    2009-02-01

    Full Text Available A ferrugem de espécies de Capsicum spp. (pimenta e pimentão, é causada pelo fungo Puccinia pampeana, pode causar perdas totais em plantios de diversas espécies de Capsicum, onde preodminam temperaturas ao redor de 21ºC. Esta ferrugem, mesmo sendo específica do gênero Capsicum, e mesmo muitas espécies dentro deste gênero sendo suscetíveis, algumas apresentam reação de hipersensibilidade. Foi o caso de Capsicum annuum (pimenta cv. Cayenne e C. chinense (pimenta cv. Habañero, que após a formação dos espermogônios (11 dias, apresentou manchas necróticas na região periférica aos espermogônios, aos 15 dias após a inoculação, não havendo evolução da infecção. Também foi observada reação de hipersensibilidade, de forma mais moderada em folhas C. annuum (pimenta serrano e C. baccatum (chapéu-de-frade. Com relação às outras solanáceas inoculadas (jiló e berinjela não foram observados os sintomas e sinais da infecção.The Capsicum spp. (pepper and green pepper rust is caused by the fungus Puccinia pampeana. This is an important disease in these crops which may cause complete losses in crops of several species of Capsicum. Although specific to the genus Capsicum, and despite the fact that many species within this genus are susceptible to rust, some of them have shown a hypersensitivity reaction. That was the case with Capsicum annuum (Cayenne pepper and C. chinense (datil pepper, which, after spermogonia formation (11 days, showed necrotic spots in the peripheral region of the spermogonia 15 days after inoculation, without evolution of the infection. A milder hypersensitivity reaction was also observed only in leaves of C. annuum (chili pepper and C. baccatum ("chapéu-de-frade". With regard to other solanaceous plants inoculated ("jiló" and eggplant, no symptoms or signs of infection were observed.

  5. Deep Crustal Earthquakes and Repeating Earthquakes in the West-Central Sierra Nevada, Western USA

    Science.gov (United States)

    Hurd, O.; Frassetto, A.; Zandt, G.; Gilbert, H.; Jones, C.; Owens, T. J.

    2006-12-01

    The Sierra Nevada EarthScope Project (SNEP) is a multiple institution, collaborative research project focused on investigating the structure and evolution of the Sierra Nevada batholith in eastern California. The first phase of the project (summer 2005-summer 2006) saw the deployment of over forty (40) broadband seismometers spanning the central Sierra Nevada from Fresno, California to just south of the Lake Tahoe region. These seismic stations recorded many small, local earthquakes in both the western foothills and high Sierra Nevada that were mostly located from 20 to 120 km north of Fresno and were not present in other regional catalogs. Seismicity in this region is notable because it occurs in the interior of a plate away from major known faults. Ninety (90) events were picked on as many as 20 SNEP stations and located. These events occurred from late May 2005 to late January 2006 at a rate of ~10 per month and were located between 10 and 35 km depth. Many of the events fall within two distinct clusters beneath the array. The first cluster contains ~45 events and is located 30-70 km east of Merced, California and 30-90 km north of Fresno, California. The second represents ~30 events and is centered about the southern Yosemite National Park region. Average depth of the events in the first cluster is ~27 km compared to ~16 km for the events in the second. Past studies have found that events from similar locations in the western Sierra Nevada foothills exhibited ML magnitudes from 0 to 3.2 and had focal mechanisms displaying strike-slip faulting combined with normal and reverse components (Wong and Savage, 1983, BSSA). Direct comparison between waveforms of picked events occurring in small clusters (2-5 events) found that some events had nearly identical waveforms. This suggests similar rupture locations and characteristics despite the events having occurred a couple days to several weeks apart.

  6. Geological and geochemical studies of the Sierra del Morro-Oeste (San Luis Province, Argentina): Meta-sediments and meta-volcanics from a probable back-arc setting

    Science.gov (United States)

    Delakowitz, B.; Höll, R.; Hack, M.; de Brodtkorb, M. K.; Stärk, H.

    The Sierra del Morro-Oeste covers an area of some 40 km 2 in the northeastern part of San Luis Province, Argentina. This area is an integral part of the scheelite- and wolframite-bearing crystalline basement of the Sierras Pampeanas. A "characteristic rock sequence"—several tens of meters thick—is concordantly embedded between uniform country rocks (quartz-oligoclase/andesine micaschists and gneises); it includes layered alternations of banded amphibolites, hornblende-epidote schists, scheelite-bearing calc-silicate rocks, lenses of barren marble, and, locally, tourmaline-bearing micaschists. Chemical analyses of amphibolite samples allow these metamorphic rocks to be interpreted as derivatives of a tholeiite-basaltic volcanism. The amphibolites are subdivided into two groups (A and B) because of significant differences in their chemical composition. These differences are related to hydrothermal seafloor alteration. This sea-water alteration has been most effective in the youngest tholeiite-basaltic lava extrusions. The derivatives of the submarine altered tholeiite-basaltic lavas (amphibolites of Group B) can therefore be interpreted as younger in comparison with the primary lavas of the non-altered amphibolites of Group A. The extrusion of the tholeiite-basaltic lavas obviously took place during an initial stage of back-arc basin rifting on continental crust.

  7. Deposition patterns and transport mechanisms for the endocrine disruptor 4-nonylphenol across the Sierra Nevada Mountains, California.

    Science.gov (United States)

    Lyons, Rebecca; Van de Bittner, Kyle; Morgan-Jones, Sean

    2014-12-01

    Dust and particulate distribution patterns are shifting as global climate change brings about longer drought periods. Particulates act as vehicles for long range transport of organic pollutants, depositing at locations far from their source. Nonylphenol, a biodegradation product of nonylphenol polyethoxylate, is a known endocrine disruptor. Nonylphenol polyethoxylate enters the environment as an inert ingredient in pesticide sprays, potentially traveling great distances from its application site. This is of concern when a highly agricultural region, California's Central Valley, lies adjacent to sensitive areas like the Eastern Sierra Nevada Mountains. The distribution and transport mechanisms for 4-nonylphenol were investigated in Eastern Sierra Nevada canyons. Regions close to canyon headwalls showed trace amounts of 4-nonylphenol in surface water, snow, and atmospheric deposition. Exposed areas had yearly average concentrations as high as 9 μg/L. Distribution patterns are consistent with particulate-bound transport. This suggests with increasing drought periods, higher levels of persistent organic pollutants are likely.

  8. Sierra Nevada Rock Glaciers: Biodiversity Refugia in a Warming World?

    Science.gov (United States)

    Millar, C. I.; Westfall, R. D.

    2007-12-01

    Rock glaciers and related periglacial rock-ice features (RIFs) are common landforms in high, dry mountain ranges, and widely distributed throughout canyons of the Sierra Nevada, California, USA (Millar & Westfall, in press). Due to insulating rock carapaces, active rock glaciers (ice-cored) have been documented to maintain ice longer, and thus contribute to more enduring hydrologic output, under past warming climates than typical ice glaciers. This function has been suggested for the coming century. We propose a broader hydrologic and ecologic role for RIFs as temperatures rise in the future. For the Sierra Nevada, we suggest that canyons with either active or relict RIFs (Holocene and Pleistocene) maintain water longer and distribute water more broadly than canyons that were scoured by ice glaciers and are defined by primary river and lake systems. RIFs provide persistent, distributed water for extensive wetland habitat, rare in these otherwise barren, high, and dry locations. We mapped and assessed the area of wetlands surrounding active and relict RIFs from the central eastern Sierra Nevada; from these we delineated wetland vegetation community types and recorded plant species found in RIF-supported wetlands. Mid-elevation RIFs, likely inactive or with transient ice, develop soil patches on their rock matrix. At the Barney Rock Glacier (Duck Pass, Mammoth Crest), we inventoried plant species on all soil patches, and measured cover for each species per patch and total plant cover for the rock glacier. RIF landforms also appear to support high-elevation mammals. We show that American beaver (Castor canadensis) is associated with canyons dominated by active or relict RIFs and propose that the articulating, persistent, and distributed nature of streams makes dam-building easier than other canyons. Beavers further contribute to maintaining water and creating wetland habitat in upper watersheds by engineering ponds and marshes, and contributing to riparian extent. We

  9. Miracle Boy of Sierra Vista

    Institute of Scientific and Technical Information of China (English)

    Deborah; Morris; 郗莱仁

    1998-01-01

    Sierra Vista是美国亚利桑那州的一个偏僻的小镇。1990年11月12日,这里发生了一桩震惊全美的故事。 笔者的一位友人读罢此文,认为这是让人心跳的一场“劫后余生”。 文章的开头,展示了一幅温馨的家庭生活图: 11月12日这一天,正值美国的Veterans Day(退伍军人节),学校放假。Amanda,两个小孩的母亲,决定陪同她的朋友Lyne Jackson去Tucson,而她的两个小孩,Nicole,12岁,Justin,8岁,暂时由Lyne的父母照看。Nicole,Justin和Lyne的9岁的小孩Keith等一起在外面戏耍。 “劫难”的到来总是那么猝不及防: Suddenly, Keith burst inside. "Grandma, Justin’s hurt!" Keith spoke in a frightened, breathless voice,"Hurry!" 当祖母和Keith赶到出事现场时,见到的是一场惨祸; Justin was sprawled (四肢摊开躺着) on his back on the ground, his handsclutching(抓住) at a 5/8-inch-thick threaded steel rod(螺纹钢棒) buried deep in his stomach! 惨祸是如何发生的呢?原来: Justin and Keith had scaled(攀上) the magnolia (木兰树) ’s branches, then triedto leap onto the roof of the house. But Justin slipped on the shingles (屋顶板)and slidoff feet-first, plummeting (骤然跌下) 12 feet onto the

  10. Registro de Nephridiophaga sp. (Protista: Nephridiophagidae en Apis mellifera (Hymenoptera: Apidae del Sur de la región Pampeana

    Directory of Open Access Journals (Sweden)

    Santiago PLISCHUK

    2011-01-01

    Full Text Available Durante estudios prospectivos tendientes a la detección de protistas asociados a ápidos en la región Pampeana, se observó la presencia de esporos ovales bicóncavos y grupos de esporos (cúmulos en los túbulos de Malpighi de abejas de Dufaur, partido de Saavedra, sudoeste de la provincia de Buenos Aires. Los esporos maduros midieron 4,8 ± 0,05 x 2,4 ± 0,03 μm y la carga (intensidad promedió 5,71 ± 1,49 x 106 esporos/abeja. Las detecciones se efectuaron entre julio y octubre de 2006 y la prevalencia en las colmenas positivas osciló entre 1 y 16,7 %. Las características morfológicas de los esporos, el lugar de desarrollo y la especie huésped involucrada sugieren que el microorganismo en cuestión, pertenece al género Nephridiophaga y sería N. apis Ivanić, especie tipo cuyo conocimiento es extremadamente limitado. El hallazgo constituye el primer registro de un nefridiofágido asociado a A. mellifera fuera del continente europeo.

  11. Arqueología de cazadores recolectores del sector centro-oriental de la región pampeana

    Directory of Open Access Journals (Sweden)

    Daniel Loponte

    2003-11-01

    Full Text Available El humedal asociado al rio Paraná inferior y tramo superior del Rio de la Plata, situado en el sector centro-oriental de la región pampeana, muestra un registro arqueológico de gran complejidad. Esta situación parece estar ya establecida hace 1700 anos AP. Algunas de las propiedades del mismo sugieren una importante concentración de poblaciones humanas en el área, con reducida movilidad residencial e intensificación en la explotación de los recursos de alto ranking y una especial concentración en la explotación de los recursos fluviales. La fuerte diversidad estilística que se observa en los patrones de decoración de la alfarería y en el tratamiento de la muerte, son coherentes con la existencia de una compleja y variada identidad social, cuya dinámica posiblemente estuvo influenciada por conductas densodependientes que se acrecentaron aun mas por el arribo de grupos horticultores amazónicos.

  12. The Special Court for Sierra Leone

    DEFF Research Database (Denmark)

    Damgaard, Ciara Therése

    2004-01-01

    The focus of this article is the Special Court for Sierra Leone and the extent to which it can be said that the Special Court has already challenged, or will, in the future, challenge the tradition of impunity for gender-based crimes. In this regard, an analysis is undertaken of the Special Court......'s Statute, Rules of Procedure and Evidence and practice to date, in order to determine its treatment of gender-based crimes and whether it can be said that the Special Court for Sierra Leone challenges the tradition of impunity for gender-based crimes. Udgivelsesdato: december 2004...

  13. The surface of crystalline basement, Great Valley and Sierra Nevada, California: A digital map database

    Science.gov (United States)

    Wentworth, Carl M.; Fisher, G. Reid; Levine, Paia; Jachens, Robert C.

    1995-01-01

    Crystalline basement in central California extends westward from the exposed Sierra Nevada beneath the sedimentary fill of the Great Valley and under the eastern edge of the Coast Ranges at mid-crustal depth. The surface of this basement is defined from three types of control: in the Sierra Nevada from the topography itself, beneath the eastern two thirds of the Great Valley in considerable detail from numerous wells drilled for oil and gas, and beneath the western San Joaquin Valley in less detail from seismic reflection and refraction profiles. Together, these data demonstrate that the surface of crystalline rock is continuous from the exposed rock in the mountains to the top of high-velocity rock buried deep beneath the eastern front of the southern Coast Ranges. This report presents a compilation of data through 1985 that define the surface of this crystalline basement, a contour map of the surface, and the lithology of the basement rock sampled by many of the wells. The compilation was begun as part of the investigation of the 1983 Coalinga earthquake, and was subsequently converted to digital form and extended to the whole of the Great Valley and Sierra Nevada. The main purpose was to explore and document the shape and continuity of the basement surface and to determine the relation of the surface to the tectonic wedge hypothesis (Wentworth and others, 1984; Wentworth and Zoback, 1989). Available basement samples from wells - principally the thin-section collection of May and Hewitt (1948) preserved by the California Academy of Sciences - were also reexamined by cooperating petrologists in an effort to distinguish wells that bottomed in ophiolitic rocks.

  14. NATURAL RESOURCE MANAGEMENT IN THE SIERRA OF SONORA UNDER THE SCHEME UMAFOR. CASE STUDY: SIERRA ALTA AND SIERRA LA MADERA

    Directory of Open Access Journals (Sweden)

    Hugo Silva-Kurumiya

    2011-05-01

    Full Text Available This paper shows the use and value of natural resources from a social, sustainable and legal perspective, under the scheme of Sustainable Forest Management Units (UMAFOR by its Spanish acronym. Two participatory workshops were carried out in March 2010, one in UMAFOR Sierra La Madera and another in UMAFOR Sierra Alta, belonging to the Sierra de Sonora. An adaptation of “Problems, Causes and Consequences” of Ramírez-García (2004 methodology was used to discuss issues such as conservation, productive activities, society, laws, research and support programs. The objective was to analyze challenges and opportunities in the Sierra de Sonora under this management scheme. The ratting of natural resource for inhabitant and producers was documented based in ecosystems type and its value for use. Economic value was the most important for productive and non productive use; however, there are opportunities to transit from traditional to sustainable activities. Local producers are interested in linking whit research centers and consultants to get support for diversification of productive activities. It is possible to have changes according to sustainable development; UMAFOR is an alternative to achieve those changes.

  15. Diurnal raptors in the fragmented rain forest of the Sierra Imataca, Venezuela

    Science.gov (United States)

    Alvarez, E.; Ellis, D.H.; Smith, D.G.; LaRue, C.T.; Bird, David M.; Varland, Daniel E.; Negro, Juan Jose

    1996-01-01

    The rain forest of the Sierra Imataca in eastern Venezuela has been subjected to extensive deforestation for pastures and agricultural settlements. In the last decade the opening of access roads combined with intensified logging and mining activities have fragmented a significant portion of the remaining forest. We noted local distribution and habitat use for 42 species of diurnal raptors observed in affected areas in this region. We observed some raptors considered as forest interior species and other open country species foraging and roosting in man-made openings inside the forest.

  16. Niveles de carbono orgánico y ph en suelos agrícolas de las regiones pampeana y extrapampeana argentina Organic carbon and ph levels in agricultural soils of the pampa and extra-pampean regions of argentina

    Directory of Open Access Journals (Sweden)

    Hernán René Sainz Rozas

    2011-07-01

    Full Text Available El carbono orgánico (CO y el pH de los suelos son indicadores clave de la salud del suelo. El objetivo de este trabajo fue relevar el contenido de CO y pH actual (0-20 cm de los suelos agrícolas de las regiones pampeana y extrapampeana de la Argentina y realizar mapas con ambas variables, utilizando la mediana de cada partido. Otro objetivo fue comparar la eficiencia de predicción (EP de dos métodos de interpolación: 1 el método inversa de la distancia ponderada (IDP y 2 el método Kriging ordinario (KO. El número de muestras utilizados para CO y pH fue de 31.619 y 31.398, respectivamente, las que fueron tomadas en lotes de producción en 2005 y 2006. Ambos métodos produjeron mapas similares de CO y pH, pero la EP fue ligeramente mayor para el KO (65 a 80% comparado al IDP (63 a 79%. Los valores de CO variaron de 5,5 a 38,0 g kg-1, determinándose los contenidos más bajos al oeste y norte, y los más elevados al sudeste (SE de la región. Los suelos de la mayor parte del área relevada presentaron valores de pH de 6 a 7,5, salvo algunos del norte de Buenos Aires, centro-sur de Santa Fe y este de Córdoba que mostraron valores de pH de 5,5-6. El contenido de CO manifiesta una tendencia declinante e indica la necesidad de aplicar prácticas de manejo de suelo tendientes a revertir este proceso degradativo. El pH de los suelos no sería limitante para la producción de cultivos en la mayor parte del área, pero se pueden presentar potenciales problemas de acidez en determinadas zonas.Soil organic carbon (SOC and pH are considered key indicators of soil health. The objective of this study was to determine SOC and soil pH of agricultural soils (0-20 cm in the pampeana and extrapampeana regions of Argentina and to elaborate maps with both variables, using the median of each county. Soil samples were taken from fields that were sampled in 2005 and 2006 at a 20 cm-soil depth and totalled 31,619 and 31,398 for SOM and pH, respectively. The

  17. Particularizing Universal Education in Postcolonial Sierra Leone

    Science.gov (United States)

    Pai, Grace

    2013-01-01

    This paper presents a vertical case study of the history of universalizing education in postcolonial Sierra Leone from the early 1950s to 1990 to highlight how there has never been a universal conception of universal education. In order to unite a nation behind a universal ideal of schooling, education needed to be adapted to different…

  18. The Cora: People of the Sierra Madre.

    Science.gov (United States)

    Lane, Sarah; And Others

    This text explores an isolated and indigenous people who live in the Sierra Madre Occidental in Mexico. Isolation has allowed the Cora Indians to maintain their traditional customs to a much greater extent than many other groups of Native Americans. The historical and geographical contexts of the Cora are presented in this curriculum resource.…

  19. Un acercamiento a la dimensión simbólica de la cultura material en la región pampeana

    OpenAIRE

    2006-01-01

    Este trabajo tiene como finalidad comenzar a evaluar cuáles podrían ser algunos de los derivados materiales de la esfera ideacional en la arqueología pampeana. Para ello, se tienen en cuenta teorías antropológicas sobre la religión e indicadores arqueológicos empleados para tratar este tema. Con este objetivo general se recurre al caso particular del sitio Nutria Mansa 1, donde se discute la evidencia allí recuperada en el marco del registro arqueológico regional. Además, a los efectos de int...

  20. La herencia: los/as hijas y el tránsito entre generaciones en la agricultura familiar de la región pampeana argentina

    OpenAIRE

    Neiman, Melina

    2015-01-01

    Las distintas formas hereditarias o de transición generacional han sido motivo de intensos debates en las ciencias sociales en general y en la sociología rural en particular, tanto para la agricultura de los países avanzados como de las regiones en desarrollo. En la región pampeana argentina, estos procesos sufrieron importantes transformaciones. Por un lado, se pasó de heredar un oficio a heredar un bien inmueble de alto valor. Por el otro, hubieron modificaciones en las dinámicas familiares...

  1. MISR Sees the Sierra Nevadas in Stereo

    Science.gov (United States)

    2000-01-01

    These MISR images of the Sierra Nevada mountains near the California-Nevada border were acquired on August 12, 2000 during Terra orbit 3472. On the left is an image from the vertical-viewing (nadir) camera. On the right is a stereo 'anaglyph' created using the nadir and 45.6-degree forward-viewing cameras, providing a three-dimensional view of the scene when viewed with red/blue glasses. The red filter should be placed over your left eye. To facilitate the stereo viewing, the images have been oriented with north toward the left.Some prominent features are Mono Lake, in the center of the images; Walker Lake, to its left; and Lake Tahoe, near the lower left. This view of the Sierra Nevadas includes Yosemite, Kings Canyon, and Sequoia National Parks. Mount Whitney, the highest peak in the contiguous 48 states (elev. 14,495 feet), is visible near the righthand edge. Above it (to the east), the Owens Valley shows up prominently between the Sierra Nevada and Inyo ranges.Precipitation falling as rain or snow on the Sierras feeds numerous rivers flowing southwestward into the San Joaquin Valley. The abundant fields of this productive agricultural area can be seen along the lower right; a large number of reservoirs that supply water for crop irrigation are apparent in the western foothills of the Sierras. Urban areas in the valley appear as gray patches; among the California cities that are visible are Fresno, Merced, and Modesto.MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  2. A seismological and petrological crustal model for the southwest of the Sierra de Pie de Palo, province of San Juan Modelo cortical sismológico y petrológico para el sudoeste de la sierra de Pie de Palo, provincia de San Juan

    Directory of Open Access Journals (Sweden)

    Brígida Castro de Machuca

    2012-06-01

    Full Text Available A seismic velocity analysis from teleseismic receiver functions recorded in the southwestern fank of the Sierra de Pie de Palo (Western Sierras Pampeanas, Argentina, is compared with seismic properties directly calculated from lithological composition. The seismological results show an upper layer located in the first 13 km depth. A deeper contrast in seismic velocities is found at a depth of 28 km; the petrological results indicate a composition compatible with observed greenschist and amphibolite facies mafic rocks up to this depth. The receiver function measurements at 13 km and 28 km depths could be interpreted as two potential décollement levels that might have favoring a mechanism to thicken the whole crust, which produces a receiver function Moho signal located at 47 km depth. In addition, the lower crust between 28 km and 47 km exhibits high seismic P-wave velocities and Vp/Vs ratio (> 1.80 that are representative of a densification consistent with upper amphibolite to granulite/ecoglite facies lithologies. Based on these results, the combined petrological and seismological analyses suggest the continuation of the same mafic-crust outcropping lithologies into the lower levels of the 47-km thickened crust, which could be part of the Pie de Palo Complex ophiolite belt or the Precordillera basement.Un análisis de funciones del receptor registradas en el suroeste de la Sierra de Pie de Palo (Sierras Pampeanas Occidentales, Argentina, se compara con propiedades sísmicas directamente calculadas a partir de la composición litológica. Los resultados sismológicos indican una capa superior en los primeros 13 km. Otra zona de contraste entre las velocidades de ondas sísmicas, más profunda, se encuentra a unos 28 km; los resultados del análisis petrológico indican una composición compatible con rocas máficas en facies de esquistos verdes y anfibolitas hasta esa profundidad. Las observaciones de función del receptor a 13 y 28 km de

  3. Petrología y geoquímica de la unidad ígnea Quebrada Blanca, sierra de la Huerta, Provincia de San Juan Petrology and geochemistry of the Quebrada Blanca Igneous Unit, Sierra de La Huerta, province of San Juan.

    Directory of Open Access Journals (Sweden)

    Brígida Castro de Machuca

    2011-12-01

    Full Text Available La unidad ígnea Quebrada Blanca (Pérmico Superior-Triásico inferior, que intruye al basamento cristalino de la sierra de La Huerta, Sierras Pampeanas Occidentales, es el término más diferenciado de un grupo de rocas ígneas de edad y características similares. Está compuesta por un cuerpo hipabisal de pórfido riolítico, una brecha hidrotermal-intrusiva en la que se distinguen dos facies con marcadas diferencias texturales y composicionales, y diques felsíticos/riolíticos. Esta asociación rocosa define la raíz de una diatrema expuesta por la erosión. La génesis de la brecha estuvo asociada a la cristalización del pórfido riolítico, al brechamiento explosivo y a la exsolución de fluidos magmático-hidrotermales que fracturaron la caperuza solidificada del intrusivo y las rocas metamórficas circundantes, transportando los fragmentos hacia niveles más superficiales. El pórfido se terminó de emplazar con posterioridad, probablemente ocupando el conducto alimentador. Los datos geoquímicos indican para estas litologías contenidos altos en sílice, carácter subalcalino, calcoalcalino de alto K, y afinidad metaluminosa a débilmente peraluminosa. Los contenidos de elementos litófilos de gran radio iónico son altos mientras que los de Sr, P y Ti son bajos. Presentan enriquecimiento en LREE y empobrecimiento en HREE con la relación (La/YbN = 3,37 a 13,67. Las características geoquímicas son compatibles con las de rocas ígneas generadas en arcos volcánicos. Esta unidad es correlacionada tentativamente con la sección superior (dacítica-riolítica del Grupo Choiyoi, y se la asigna a las etapas finales de la evolución del arco magmático continental emplazado a lo largo del borde occidental de Gondwana a partir del Carbonífero superior.The Quebrada Blanca igneous unit (Upper Permian-Lower Triassic intruding the crystalline basement of the Sierra de La Huerta, Western Sierras Pampeanas, is the most differentiated member of a

  4. La dinámica del poblamiento humano del Sudeste de la Región Pampeana durante el Holoceno

    Directory of Open Access Journals (Sweden)

    Gustavo Barrientos

    2002-12-01

    Full Text Available El objetivo de este trabajo es discutir una serie de conceptos (v.g. población local, metapoblación, útiles para comprender la dinámica del poblamiento humano del Sudeste de la Región Pampeana durante el Holoceno. Dicha dinámica es concebida como el resultado de la alternancia de procesos de retracción y expansión poblacional (demográfica y geográfica, incluyendo ocasionalmente eventos significativos tales como la extinción local y la recolonización de espacios. Dos procesos, probablemente conducentes al reemplazo poblacional a nivel regional, son considerados en este trabajo: uno, ocurrido durante el Holoceno medio (ca. 6.000 a 4.000 años AP y otro, acontecido durante la fase final del Holoceno tardío (ca. 1.000 a 500 años AP. Ambos casos habrían involucrado el ingreso al área de poblaciones con distinto grado de vinculación con las poblaciones preexistentes, aunque probablemente obedeciendo a causas distintas. En base al análisis biométrico del esqueleto craneofacial de muestras diacrónicas del Sudeste de la Región Pampeana y del N.E. de Patagonia, se ponen a prueba estas dos hipótesis.A central goal of this paper is to introduce and discuss useful concepts (e.g., local populations and metapopulations for better understanding the dynamics of the human peopling of the Southeastern Pampean Region during the Holocene. Such a dynamic is conceived as resulting from alternating processes of population retraction and expansion (both demographic and geographic, occasionally including some significant events like local extinction and re-colonization. Two main processes, probably involving population replacement at the regional level, are considered. The first process occurred in the Mid Holocene (ca. 6000-4000 BP, and the second at the end of the Late Holocene (ca. 1000-500 BP. Both cases may involve the entry into the area of populations with a distinct degree of relatedness with respect to the pre-existent local populations

  5. Petrología, Geoquímica y Geología estructural de la Sierra de Copacabana (provincia de Catamarca, República Argentina y su significado geotectónico en el contexto del margen occidental del Gondwana

    Directory of Open Access Journals (Sweden)

    López, J. P.

    1998-08-01

    Full Text Available Copacabana Range is an orographic unit of the Sistema de Famatina at the W of Sierras. Both the pampean metamorphic basament and the granitoids emplaced in a continental margin during the Famatinian Cycle were affected during the upper Ordovicic-Siluric by a deformative regime that could has produced typical rocks deformed by dynamic metamorphism (cataclasites, protomylonites, ortomylonites and ultramylonites. The structural study allowed us to interpret that the deformative regime could has occasioned a compressive tectonic toward the west, associated with a continental collision during the Ocloyic orogenic.La Sierra de Copacabana es una unidad orográfica emplazada en el ambiente de Sierras Pampeanas Noroccidentales, al E del Sistema de Famatina. Tanto su basamento, compuesto por rocas metamórficas de grado medio formadas durante el ciclo Pampeano, como los granitoides de carácter calcoalcalino y peralumínico que intruyen en un margen continental activo durante el Ciclo Famatiniano (Paleozoico inferior, fueron afectados por procesos deformativos que habrían producido las rocas típicas del metamorfismo dinámico (cataclasitas, protomilonitas, ortomilonitas y ultramilonitas reconocidas en amplios sectores de la Sierra de Copacabana y en las serranías vecinas, durante el Ordovícico- Silúrico superior. El estudio estructural permitió definir este proceso deformativo que habría ocasionado una tectónica compresiva de carácter inverso hacia el oeste, relacionado con la colisión continente-continente durante la Orogenia Oclóyica (Ordovícico superior-Silúrico.

  6. Transverse fold evolution in the External Sierra, southern Pyrenees, Spain

    Science.gov (United States)

    Anastasio, David J.; Holl, James E.

    2001-02-01

    Fault-slip data are used to reconstruct varying tectonic regimes associated with transverse fold development along the eastern and southern margins of the Jaca basin, southern Pyrenees, Spain. The Spanish Pyrenean foreland consists of thrust sheets and leading-edge décollement folds which developed within piggyback basins. Guara Formation limestones on the margins of the Jaca basin were deposited synchronously with deformation and are exposed in the External Sierra. Within the transverse folds, principal shortening axes determined from P and T dihedra plots of fault-slip data show a shift from steep shortening in stratigraphically older beds to NNE-SSW horizontal shortening in younger beds. Older strata are characterized by extensional faults interpreted to result from halotectonic (salt tectonics) deformation, whereas younger strata are characterized by contraction and strike-slip faults interpreted to result from thrust sheet emplacement. The interpretation of the timing for the shortening axes in the younger strata is supported by the observation that these axes are parallel to shortening axes determined from finite strain analysis, calcite twins, and regional thrusting directions determined from fault-related folds and slickenlines. This study shows that fault population analysis in syntectonic strata provides an opportunity to constrain kinematic evolution during orogeny.

  7. Archaeological obsidian from La Sierra Gorda Mexico, by PIXE

    Energy Technology Data Exchange (ETDEWEB)

    Juarez-Cossio, D.; Terreros, E.; Quiroz-Moreno, J.; Romero-Sanchez, S. [Instituto Nacional de Antropologia e Historia, Mexico. Seminario 8, Col. Centro. 06060 Mexico, DF (Mexico); Calligaro, T.F. [Centre de Recherche et de Restauration des Musees de France, UMR 171, Palais du Louvre-Porte des Lions, 14, Quai Francois Mitterrand, 75001 Paris (France); Tenorio, D. [Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, 11801 Mexico, DF (Mexico)], E-mail: dolores.tenorio@inin.gob.mx; Jimenez-Reyes, M. [Instituto Nacional de Investigaciones Nucleares, Apdo. Postal 18-1027, 11801 Mexico, DF (Mexico); Los Rios, M. de [Instituto Nacional de Antropologia e Historia, Mexico. Seminario 8, Col. Centro. 06060 Mexico, DF (Mexico)

    2009-04-15

    The chemical compositions of 42 obsidian pre-Hispanic artifacts from Tancama and Purisima, both archaeological sites of La Sierra Gorda Valleys, Mexico, were analyzed by PIXE technique. These obsidians came from four sources: Sierra de Pachuca Hidalgo, Paraiso Queretaro, Ucareo Michoacan and mainly from Zacualtipan/Metzquititlan Hidalgo. According to archaeological evidences, La Sierra Gorda valleys participated in commercial exchange with other regional sites, from Classic to Post-classic periods (A.D. 300-1500)

  8. SIERRA Toolkit v. 2.0

    Energy Technology Data Exchange (ETDEWEB)

    2016-09-14

    The SIERRA Toolkit is a collection of libraries to facilitate the development of parallel engineering analysis applications. These libraries supply basic core services that an engineering application may need such as a parallel distributed and dynamic mesh database (for unstructured meshes), mechanics algorithm support (parallel infrastructure only), interfaces to parallel solvers, parallel mesh and data I/O, and various utilities (timers, diagnostic tools, etc.)

  9. EASTERN UGANDA

    African Journals Online (AJOL)

    EVALUATION OF SELECTED ELITE POTATO GENOTYPES IN. EASTERN ... Significant

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

    Directory of Open Access Journals (Sweden)

    Andreo, B.

    1995-04-01

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

  11. La estructura del Grupo Sierras Bayas en el sector norte de las sierras homónimas, noroeste de las Sierras Septentrionales de Buenos Aires

    OpenAIRE

    A.C. Massabie; O.E. Nestiero

    2005-01-01

    El Grupo Sierras Bayas, de edad precámbrica tardía, se halla integrado por las formaciones sedimentarias Villa Mónica, Cerro Largo y Loma Negra, y forman parte de la porción noroccidental de las Sierras Septentrionales de Buenos Aires. Los afloramientos principales, relativamente aislados en serranías bajas, se ubican en los alrededores de Olavarría, particularmente en las Sierras Bayas, y con menor extensión en cercanías a la localidad de Barker. La morfoestructura de conjunto de estas sedim...

  12. Sierra Elvira limestone: petrophysical characteristics of an Andalusian heritage stone

    Directory of Open Access Journals (Sweden)

    Valverde, I.

    2008-06-01

    Full Text Available “Sierra Elvira stone” is one of the ornamental building stones most widely used in the historical monuments of eastern Andalusia. A Liassic age limestone, it appears in the central section of the Baetic Mountains and more specifically in the Middle Subbaetic domain. While the most common variety is a crinoid limestone, a micritic limestone of the same age has also been quarried, albeit in much smaller quantities. These stones form very thick beds, up to nearly 5 m deep, that run in consistently parallel lines and have a dip angle that facilitates quarrying.With petrographic, physical and mechanical properties that ensure stone strength and durability, it is a high quality building material suitable for both structural and ornamental purposes. These properties can be attributed to the minimal open porosity and concomitant excellent water resistance that characterize the stone, as well as to its high mechanical strength and low textural anisotropy, both elastic and mechanical. With such attributes, the stone can be successfully used for any number of purposes, including decorative stonework (portals, fountains, plinths, structural members (column shafts and bases or urban curbing and paving. Intervention on Sierra de Elvira limestone structures should be limited to cleaning or repair, for consolidating or protective materials are scantly effective.La “Piedra de Sierra Elvira” constituye una de las piedras ornamentales más significativas del Patrimonio Arquitectónico de Andalucía Oriental. Es una roca caliza del Lias que aflora en el Subbético Medio del sector central de las Cordilleras Béticas. El litotipo más explotado es una caliza con crinoides, en bastante menor importancia se ha extraído también otra caliza micrítica de la misma edad. Los bancos son muy potentes, en algunos casos de más de 5 m, con un paralelismo constante y un buzamiento que favorece su explotación en los frentes de cantera.Sus caracter

  13. British Military Intervention into Sierra Leone: A Case Study

    Science.gov (United States)

    2007-12-14

    BRITISH MILITARY INTERVENTION INTO SIERRA LEONE : A CASE STUDY A thesis presented to the Faculty of the U.S. Army Command and...NUMBER 5b. GRANT NUMBER 4. TITLE AND SUBTITLE British Military Intervention into Sierra Leone : A Case Study 5c. PROGRAM ELEMENT NUMBER 5d...

  14. Indigenous Knowledge and Library Work in Sierra Leone

    Science.gov (United States)

    Kargbo, John Abdul

    2006-01-01

    Indigenous knowledge is vital information that is sadly diminishing at an alarming rate in Sierra Leone. There is, therefore, an urgent need to collect it before much of it is completely lost. This article explores the concept of indigenous knowledge and indigenous knowledge systems with a particular focus on Sierra Leone. Definitions and…

  15. Increased precipitation acidity in the central Sierra Nevada

    Science.gov (United States)

    Byron, Earl R.; Axler, Richard P.; Goldman, Charles R.

    Between 1979 and 1986, precipitation acidity increased significantly on the crest of the central Sierra Nevada. Variation in precipitation pH was closely associated with change in nitrate concentrations but not to sulfate. This area of the Sierra Nevada crest contains many acid-sensitive, poorly buffered lakes and ponds which can be adversely affected by increasing precipitation acidity.

  16. Evaluación de la capacidad buffer de suelos ácidos de la pradera pampeana para el diagnóstico de la necesidad de corrector

    OpenAIRE

    2016-01-01

    La capacidad tampón o buffer de un suelo es un factor clave para determinar la dinámica de la acidificación y por ende, de la necesidad de tratamiento. Una de las formas de determinar este poder regulador es a través de curvas de titulación. Objetivos: evaluar la evolución del pH de diferentes suelos ácidos representativos de taxones de amplia difusión areal de la Región Pampeana, ante el agregado de dosis crecientes de álcali y ácido, a los fines de brindar pautas científicas para su tratami...

  17. Sobre la homogeinización de la presión fiscal en la agricultura pampeana tras la devaluación.

    OpenAIRE

    Diego Ariel Fernández

    2014-01-01

    La década del ’90 marcó una fuerte aceleración del proceso de concentración económica de la producción agrícola pampeana, evolución que continuaría tras la devaluación de 2002. En la determinación del mismo convergen distintos factores: las economías de escala, el manejo cambiario, la evolución tecnológica (entre otros). En este trabajo se estudia uno de estos condicionantes: la política impositiva del Estado Nacional. Se analizan los tributos que gravan al agro y sus alícuotas, diferenciando...

  18. Shatter cones at sierra madera, Texas.

    Science.gov (United States)

    Howard, K A; Offield, T W

    1968-10-11

    Shatter cones abound in the central uplift of Sierra Madera and they occur as far as 6.5 kilometers from the center. Apical angles average near 90 degrees. Whole cones and full cones represented by diversely oriented cone segments in any structural block show relatively uniform orientations of axes and a dominant direction of point. The cones predate faulting and folding in the central uplift, and, when beds are restored to horizontal, most cones point inward and upward, a pattern that supports the hypothesis of an impact origin.

  19. Uranium-lead isotopic ages from the Sierra Nevada Batholith, California

    Science.gov (United States)

    Chen, James H.; Moore, James G.

    1982-06-01

    This study provides new information on the timing and distribution of Mesozoic magmatic events in the Sierra Nevada batholithic complex chiefly between 36° and 37°N. latitude. U-Pb ages have been determined for 133 zircon and 7 sphene separates from 82 samples of granitoid rocks. Granitoid rocks in this area range in age from 217 to 80 m.y. Triassic intrusions are restricted to the east side of the batholith; Jurassic plutons occur south of the Triassic plutons east of the Sierra Nevada, as isolated masses within the Cretaceous batholith, and in the western foothills of the range; Cretaceous plutons form a continuous belt along the axis of the batholith and occur as isolated masses east of the Sierra Nevada. No granitic intrusions were emplaced for 37 m.y. east of the Sierra Nevada following the end of Jurassic plutonism. However, following emplacement of the eastern Jurassic granitoids, regional extension produced a fracture system at least 350 km long into which the dominantly mafic, calc-alkalic Independence dike swarm was intruded 148 m.y. ago. The dike fractures probably represents a period of regional crustal extension caused by a redistribution of the regional stress pattern accompanying the Nevadan orogeny. Intrusion of Cretaceous granitic plutons began in large volume about 120 m.y. ago in the western Sierra Nevada and migrated steadily eastward for 40 m.y. at a rate of 2.7 mm/y. This slow and constant migration indicates remarkably uniform conditions of subduction with perhaps downward migration of parent magma generation or a slight flattening of the subduction zone. Such steady conditions could be necessary for the production of large batholithic complexes such as the Sierra Nevada. The abrupt termination of plutonism 80 m.y. ago may have resulted from an increased rate of convergence of the American and eastern Pacific plates and dramatic flattening of the subduction zone. U-Pb ages of the Giant Forest-alaskite sequence in Sequoia National Park are

  20. Economic concentration in the Pampeana region: The case of the financial trustfunds Concentración económica en la región pampeana: El caso de los fideicomisos financieros

    Directory of Open Access Journals (Sweden)

    Diego Ariel Fernández

    2010-01-01

    Full Text Available In the last decade of the twentieth century, the trend of economic concentration of the agrarian production of the pampas region was strengthen, expressed in a mayor reduction of the sectorïs firms. Even when there is no census data to quantify it after the 2001-2002 crisis, there are several signs that imply that this process continues in the present. Big lessee capitals appear on the leading roll, managing to obtain economies of scale by taking a large tract of land, which allows them to displace their smaller rivals thanks to their capacity to propose the owners a bigger rent or better conditions to pay it. This paper offers the results of an investigation about one of the juridical forms that this process adopts: the setting up of Financial Trust Funds (FTF. The growth of this kind of financial tool since 2004 has been impressive, and it was partially used in the agrarian sector. After systematize the information of the FTFs placed in the market in the 2004-2008 period, this paper focus its attention on the ones that finance agrarian activities. It estimates the weight they have in the capitalization of the sector, analyzing the productive strategies and characteristics of those that have per purpose the sowing in leased lands, allowing us to offer concrete figures about the microeconomic base of the sector's concentration.Durante la última década del siglo XX, la producción agropecuaria de la región pampeana ve reforzada su tendencia a la concentración económica, reduciéndose de forma muy significativa el número de EAPs. Si bien no existen relevamientos censales que den cuenta de lo ocurrido tras la crisis de 2001-2002, numerosos indicios señalan que este proceso continúa en la actualidad. Aparecen como protagonistas del mismo grandes capitales arrendatarios que logran, al tomar superficies lo suficientemente amplias, obtener economías de escala que les permiten desplazar a rivales menores merced a su posibilidad de ofrecer

  1. Plutonism in the central part of the Sierra Nevada Batholith, California

    Science.gov (United States)

    Bateman, Paul C.

    1992-01-01

    The Sierra Nevada batholith comprises the plutonic rocks of Mesozoic age that underlie most of the Sierra Nevada, a magnificent mountain range that originated in the Cenozoic by the westward tilting of a huge block of the Earth's crust. Scattered intrusions west of the batholith in the western metamorphic belt of the Sierra Nevada and east of the Sierra Nevada in the Benton Range and the White and Inyo Mountains are satellitic to but not strictly parts of the Sierra Nevada batholith. Nevertheless, all the plutonic rocks are related in origin. The batholith lies along the west edge of the Paleozoic North American craton, and Paleozoic and early Mesozoic oceanic crust underlies its western margin. It was emplaced in strongly deformed but weakly metamorphosed strata ranging in age from Proterozoic to Cretaceous. Sedimentary rocks of Proterozoic and Paleozoic age crop out east of the batholith in the White and Inyo Mountains, and metamorphosed sedimentary and volcanic rocks of Paleozoic and Mesozoic age crop out west of the batholith in the western metamorphic belt. A few large and many small, generally elongate remnants of metamorphic rocks lie within the batholith. Sparse fossils from metasedimentary rocks and isotopic ages for metavolcanic rocks indicate that the metamorphic rocks in the remnants range in age from Early Cambrian to Early Cretaceous. Within the map area (the Mariposa 1 0 by 2 0 quadrangle), the bedding, cleavage, and axial surfaces of folds generally trend about N. 35 0 W., parallel to the long axis of the Sierra Nevada. The country rocks comprise strongly deformed but generally coherent sequences; however, some units in the western metamorphic belt may partly consist of melanges. Most sequences are in contact with other sequences, at least for short distances, but some sequences within the batholith are bounded on one or more sides by plutonic rocks. Proterozoic and Paleozoic sedimentary strata east of the Sierra Nevada and Paleozoic strata in

  2. Transformaciones agrícolas y despoblamiento en las comunidades rurales de la Región Pampeana Argentina

    Directory of Open Access Journals (Sweden)

    Stratta Fernández, Ricardo

    2010-07-01

    Full Text Available The aim of this work is to characterise the historical process of agricultural development in the Pampas and to examine —at the same time— the main features of the rural depopulation process. This characterization is accomplished by defining four historical stages, according to four criteria that point out particular aspects in them: 1 external economic conditions; 2 domestic economic policy framework.; 3 the behaviour of the factors of production and innovation; 4 the urban-rural demographic changes. It is proved that one of the most important changes of this historical process has been the loss of rural population. The historical characterization reveals the agricultural change and analyses the effects of rural depopulation and urban concentration. The reflection on these effects will be useful to understand the region better and to raise appropriate local developing policies that will enable the rural communities sustainability.

    El objetivo de este trabajo, es realizar una caracterización del proceso histórico del desarrollo agrícola en la Región Pampeana, examinando al mismo tiempo, los rasgos principales del proceso de despoblamiento rural. La caracterización se realiza definiendo cuatro etapas históricas, de acuerdo a cuatro criterios que marcan las particularidades de cada una de ellas: 1 las condiciones económicas externas; 2 el marco político y económico interno; 3 el comportamiento de los factores de la producción e innovación y 4 las variaciones demográficas urbano-rurales. Se demuestra que una de las alteraciones más importantes de este proceso histórico, ha sido la pérdida de población rural. Desde esta caracterización histórica se ponen de manifiesto las transformaciones agrícolas ocurridas y se analizan los efectos del despoblamiento y la concentración urbana. La reflexión sobre los cambios y efectos ocurridos servirán para entender mejor la región y plantear políticas de desarrollo local

  3. Polychlorinated biphenyls and toxaphene in Pacific tree frog tadpoles (Hyla regilla) from the California Sierra Nevada, USA.

    Science.gov (United States)

    Angermann, Jeffrey E; Fellers, Gary M; Matsumura, Fumio

    2002-10-01

    Pacific tree frog (Hyla regilla) tadpoles were collected throughout the Sierra Nevada mountain range, California, USA, in 1996 and 1997 and analyzed for the presence of polychlorinated biphenyls (PCBs) and toxaphene. Whole-tadpole sigma PCB levels ranged from 244 ng/g (wet wt) at lower elevations on the western slope to 1.6 ng/g high on the eastern slope, whereas sigma toxaphene levels ranged from 15.6 to 1.5 ng/g. Linear regression of PCB and toxaphene residue levels versus elevation indicated a significant relationship, with an r2 value of 0.33 for PCB and 0.45 for toxaphene indicating a significant elevation effect on PCB and toxaphene bioaccumulation in Sierra Nevada H. regilla. Tadpole samples from sites in east-facing versus west-facing drainage basins showed significant differences in PCB and toxaphene residue levels, suggesting the possibility of a rain-shadow effect in the long-range atmospheric transport of these contaminants to the Sierra Nevada Mountains.

  4. La Formación Balbuena, integrante del arco magmático pampeano en la sierra de Ambargasta, provincia de Santiago del Estero

    Directory of Open Access Journals (Sweden)

    M Koukharsky

    2003-12-01

    Full Text Available En un sector de las Sierras Pampeanas Orientales (29°25´ - 29°35´S y 63°43´ - 64°00´O, se estudió un conjunto de diques de acimutes entre 90 y 120° y espesores inferiores a los 10 m, que se incluyen en la Formación Balbuena. Sus composiciones abarcan dacitas, andesitas y andesitas basálticas y son interpretados como los representantes intermedios y básicos de una serie calcoalcalina cuyo extremo ácido se encontraría en los ya conocidos Pórfiros riodacíticos de Oncán aflorantes en el borde occidental del área. Son finamente porfíricos y se caracterizan por una intensa alteración de los componentes máficos y pastas, resultante de una importante actividad deutérica. Intruyen a los granitoides de las Formaciones Ojo de Agua y Ambargasta, ambos del Cámbrico medio a superior según determinaciones isotópicas. Sobre la base de edades K/Ar preexistentes, a las que se añaden dos nuevos valores, sumadas a observaciones de campo, se asignan los diques a un mismo ciclo magmático plutónico-volcánico, confirmando la vinculación ya aceptada en investigaciones anteriores para las volcanitas ácidas. Su signatura geoquímica apoya la existencia de un arco previamente postulado por otros autores y corresponden a una ubicación de arco a retroarco. Se habría desarrollado sobre corteza continental. La Formación Balbuena pertenecería al último de los eventos magmáticos importantes del ciclo Pampeano propuestos para la región.

  5. Anatomía de la raíz de las especies de Polygala L. (Polygalaceae) de la provincia pampeana (Argentina) usadas en la medicina popular y su comparación con P. senega y sus adulterantes

    OpenAIRE

    Novoa, María Cecilia; Monti, Claudia

    2001-01-01

    En la provincia pampeana se encuentran tres especies de Polygala L. (Polygalaceae) utilizadas en la medicina popular: Polygala linoides Poiret, P. pulchella Saint Hilaire y P. stenophylla A. Gray, con los mismos principios activos que Polygala senega L. especie de uso medicinal más conocida, originaria de Estados Unidos y Canadá. Esta última ha sido adulterada con varias especies de la familia Asteraceae: Arctium minus (Hill.) Bernh., Cichorium intybus L. y Taraxacum officinale Weber. De toda...

  6. Anatomía de la raíz de las especies de Polygala L. (Polygalaceae) de la provincia pampeana (Argentina) usadas en la medicina popular y su comparación con P. senega y sus adulterantes

    OpenAIRE

    Novoa, María Cecilia; Monti, Claudia

    2001-01-01

    En la provincia pampeana se encuentran tres especies de Polygala L. (Polygalaceae) utilizadas en la medicina popular: Polygala linoides Poiret, P. pulchella Saint Hilaire y P. stenophylla A. Gray, con los mismos principios activos que Polygala senega L. especie de uso medicinal más conocida, originaria de Estados Unidos y Canadá. Esta última ha sido adulterada con varias especies de la familia Asteraceae: Arctium minus (Hill.) Bernh., Cichorium intybus L. y Taraxacum officinale Weber. De toda...

  7. Archaeological obsidian from La Sierra Gorda Mexico, by PIXE

    Science.gov (United States)

    Juárez-Cossío, D.; Terreros, E.; Quiroz-Moreno, J.; Romero-Sánchez, S.; Calligaro, T. F.; Tenorio, D.; Jiménez-Reyes, M.; Rios, M. De Los

    2009-04-01

    The chemical compositions of 42 obsidian pre-Hispanic artifacts from Tancama and Purísima, both archaeological sites of La Sierra Gorda Valleys, México, were analyzed by PIXE technique. These obsidians came from four sources: Sierra de Pachuca Hidalgo, Paraíso Querétaro, Ucareo Michoacán and mainly from Zacualtipán/Metzquititlán Hidalgo. According to archaeological evidences, La Sierra Gorda valleys participated in commercial exchange with other regional sites, from Classic to Post-classic periods (A.D. 300-1500).

  8. Post-Ebola Syndrome, Sierra Leone.

    Science.gov (United States)

    Scott, Janet T; Sesay, Foday R; Massaquoi, Thomas A; Idriss, Baimba R; Sahr, Foday; Semple, Malcolm G

    2016-04-01

    Thousands of persons have survived Ebola virus disease. Almost all survivors describe symptoms that persist or develop after hospital discharge. A cross-sectional survey of the symptoms of all survivors from the Ebola treatment unit (ETU) at 34th Regimental Military Hospital, Freetown, Sierra Leone (MH34), was conducted after discharge at their initial follow-up appointment within 3 weeks after their second negative PCR result. From its opening on December 1, 2014, through March 31, 2015, the MH34 ETU treated 84 persons (8-70 years of age) with PCR-confirmed Ebola virus disease, of whom 44 survived. Survivors reported musculoskeletal pain (70%), headache (48%), and ocular problems (14%). Those who reported headache had had lower admission cycle threshold Ebola PCR than did those who did not (pEbola syndrome. The Ebola epidemic is waning, but the effects of the disease will remain.

  9. Adhesive joint and composites modeling in SIERRA.

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Yuki; Brown, Arthur A.; Hammerand, Daniel Carl; Adolf, Douglas Brian; Chambers, Robert S.; Foulk, James W., III (.,; )

    2005-11-01

    Polymers and fiber-reinforced polymer matrix composites play an important role in many Defense Program applications. Recently an advanced nonlinear viscoelastic model for polymers has been developed and incorporated into ADAGIO, Sandia's SIERRA-based quasi-static analysis code. Standard linear elastic shell and continuum models for fiber-reinforced polymer-matrix composites have also been added to ADAGIO. This report details the use of these models for advanced adhesive joint and composites simulations carried out as part of an Advanced Simulation and Computing Advanced Deployment (ASC AD) project. More specifically, the thermo-mechanical response of an adhesive joint when loaded during repeated thermal cycling is simulated, the response of some composite rings under internal pressurization is calculated, and the performance of a composite container subjected to internal pressurization, thermal loading, and distributed mechanical loading is determined. Finally, general comparisons between the continuum and shell element approaches for modeling composites using ADAGIO are given.

  10. Interaction of an Introduced Predator with Future Effects of Climate Change in the Recruitment Dynamics of the Imperiled Sierra Nevada Yellow-legged Frog (Rana sierrae)

    Science.gov (United States)

    I Lacan; Kathleen R. Matthews; K.V. Feldman

    2008-01-01

    Between-year variation in snowpack (from 20 to 200% of average) and summer rainfall cause large fluctuations in volume of small lakes in the higher elevation (> 3000 m) Sierra Nevada, which are important habitat for the imperiled Sierra Nevada Yellow-legged Frog, Rana sierrae. Climate change (global warming) is predicted to increase these...

  11. Population size, survival, growth, and movements of Rana sierrae

    Science.gov (United States)

    Fellers, Gary M.; Kleeman, Patrick M.; Miller, David A. W.; Halstead, Brian J.; Link, William

    2013-01-01

    Based on 2431 captures of 757 individual frogs over a 9-yr period, we found that the population of R. sierrae in one meadow–stream complex in Yosemite National Park ranged from an estimated 45 to 115 adult frogs. Rana sierrae at our relatively low elevation site (2200 m) grew at a fast rate (K = 0.73–0.78), had high overwintering survival rates (44.6–95%), lived a long time (up to 16 yr), and tended to be fairly sedentary during the summer (100% minimum convex polygon annual home ranges of 139 m2) but had low year-to-year site fidelity. Even though the amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) has been present in the population for at least 13 yr, there was no clear downward trend as might be expected from reports of R. sierrae population declines associated with Bd or from reports of widespread population decline of R. sierrae throughout its range.

  12. Initiatives for Sustainable Community Development in Sierra Leone.

    Science.gov (United States)

    Kamara, John M.; Kargbo, Stephen B.

    1999-01-01

    In Sierra Leone, two church-sponsored programs are focused on sustainable development. The Wesleyan Development Education and Awareness Programme trains people to initiate community projects. Women's Loan Scheme encourages development of small-scale enterprises. (SK)

  13. Indigenous knowledge in cattle breeding in Sierra Leone | Abdul ...

    African Journals Online (AJOL)

    ... and production under traditional cattle production system in Sierra Leone. ... were interviewed using a semi-structured questionnaire and by direct observation. ... Solid fawn color was the most preferred (93%) followed by complete spotted ...

  14. Addressing gender-based violence in the Sierra Leone conflict ...

    African Journals Online (AJOL)

    a Special Court to prosecute those who bore 'the greatest responsibility' for atrocities committed ... The civil war in Sierra Leone, from 1991 to 2002, gained certain notoriety .... and medical treatment (Charters, Horn and Vahidy 2008). Further ...

  15. Sierra Leone Journal of Biomedical Research Original Article

    African Journals Online (AJOL)

    User

    A publication of the College of Medicine and Allied Health Sciences, University of Sierra ... Failure to relieve pain of any cause has been ... interventions. Although all of these methods have varying degrees of effectiveness, use of epidural.

  16. Functional Requirements for SIERRA Version 1.0 Beta

    Energy Technology Data Exchange (ETDEWEB)

    EDWARDS, HAROLD C.; STEWART, JAMES R.; TAYLOR, LEE M.

    1999-10-01

    The objective of the SIERRA framework is to provide a common software infrastructure for massively parallel computational mechanics applications. The SIERRA framework consolidates the mechanics-independent computational services required by a diverse set of mechanics applications into a shared framework. Consolidation of these computational services eliminates their redundant development and maintenance efforts and streamlines the coupling of independently developed computational mechanics capabilities into integrated multi-mechanics applications.

  17. Political Economy of Extractives Governance in Sierra Leone

    OpenAIRE

    Fanthorpe, Richard; Gabelle, Christopher

    2013-01-01

    Sierra Leone is still recovering from a brutal civil war (1991-2002), fuelled in part by a valuable and easily extractable natural resource (diamonds). Sierra Leone now stands on the verge of an unprecedented period of economic growth, driven primarily by revenues from large-scale iron ore mining. Yet it continues to face many governance and developmental challenges. The rapid rise of the ...

  18. Sierra Structural Dynamics User's Notes

    Energy Technology Data Exchange (ETDEWEB)

    Reese, Garth M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-10-19

    Sierra/SD provides a massively parallel implementation of structural dynamics finite element analysis, required for high fidelity, validated models used in modal, vibration, static and shock analysis of weapons systems. This document provides a users guide to the input for Sierra/SD. Details of input specifications for the different solution types, output options, element types and parameters are included. The appendices contain detailed examples, and instructions for running the software on parallel platforms.

  19. International Marketing Strategy of Transformations LTD in Sierra Leone

    OpenAIRE

    Alam, Mohammed Touqeer

    2011-01-01

    The central idea of the report is to formulate an international marketing strategy for Transformations Ltd, a learning and development company based in UK for its entry in Sierra Leone market. The company wants to provide accredited British Leadership and Management qualification in Sierra Leone. The report uses theoretical framework for marketing analyses including internationalization models, entry mode, market segmentation, targeting, positioning and generic strategy. The report adopte...

  20. ROTURA INTENCIONAL DE ARTEFACTOS LÍTICOS FORMATIZADOS EN LA REGIÓN PAMPEANA BONAERENSE / Intentional Breakage of Stone Tools in the Pampean Region, Argentina

    Directory of Open Access Journals (Sweden)

    Celeste Weitzel

    2011-12-01

    Full Text Available En este trabajo abordamos la rotura intencional de ciertos objetos y específicamente de los artefactos líticos formatizados por talla. En primer lugar, presentamos una breve caracterización de los distintos tipos de fractura intencional y de los atributos que permiten identificarlas, basada en la síntesis de diversas descripciones otorgadas por otros investigadores y de resultados experimentales propios. En segundo lugar, se reseñan algunas de las explicaciones dadas a la presencia de objetos con roturas intencionales en contextos arqueológicos. La presencia de objetos con rotura intencional fue interpretada como una práctica asociada a diferentes estrategias tecnológicas y también como evidencia de prácticas rituales, según los objetos sobre los que se realiza o el contexto de depositación. Finalmente, se presentan como ejemplo dos casos de estudio de la Región Pampeana bonaerense en los que se reconocieron artefactos líticos formatizados con roturas intencionales y se proponen interpretaciones para la presencia de esta práctica en estos sitios.   Palabras clave: Rotura intencional; Artefactos líticos formatizados; Decisiones tecnológicas; Prácticas rituales; Región Pampeana.   Abstract In this paper we deal with the intentional breakage of objects, more precisely with intentional breakage of flaked stone tools. In the first place we present a brief characterization of different types of intentional fractures on lithics and of those traits that allows their recognition. This characterization is based on a synthesis of the descriptions given by other researchers and our own experimental results. The deliberate breakage of objects has been given different explanations according to the specific contexts in which it was recognized and to the objects on which it was performed. It has been linked to different technological strategies and it has been also considered as evidence of ritual practices. Finally, we present two case

  1. Formación de megacristales de feldespato potásico en el sector sur del batolito Cerro Aspero-Alpa Corral (32°40'S y 64°50'W, Sierras Pampeanas, Córdoba, Argentina

    Directory of Open Access Journals (Sweden)

    Pinotti, L. P.

    1992-12-01

    Full Text Available The surrounding rocks of studied area are composed by a metamorphic sequence which includes gneisses, schists, amphibolites, marbles and heterogeneous migmatites in non-conformity intruded by a granitic pluton. All this sequence is dated as having late-Precambric to mid-Paleozoic age.Three facies, mostly of monzogranitic composition, were identified. This study focuses on the porphiric facies; detailed petroestructural studies being performed, the orientation of large microcline crystal and associated microgranular enclaves being measured.Different primary flow directions were determined with track variation of microcline megacrystal and enclaves from subvertical to nearly horizontal positions.These changes have been interpreted as a convective system within the pluton.The presence of a marked planar fabric in microcline megacrystals along with phenomena such a size-variation of crystal, synneusis, crystal trending at the enclave's border and crystal accumulation, proves their early magmatic origin. The enclaves show a cinematic of deformation produced by simple shear.El entorno encajante de la zona estudiada está integrado por una secuencia metamórfica que incluye gneises, esquistos, anfibolitas, calizas cristalinas y migmatitas heterogéneas, intruidas discordantemente por el plutón granítico. A este conjunto puede asignársele una edad precámbrica superior-paleozoica media.Se identificaron tres facies, en su mayoría de composición monzogranítica, diques micrograníticos a aplíticos y enclaves. En este trabajo se pone énfasis en la facies porfiroide efectuándose estudios petroestructurales de detalle, tomando como indicadores la orientación de los grandes cristales de microclina y enclaves microgranulares asociados.Se determinaron distintas direcciones de flujo primario con variaciones en la trayectoria de los megacristales de microclina y enclaves desde posiciones subverticales hasta aproximadamente horizontales. Estos cambios han sido interpretados como un sistema convectivo dentro del plutón.La presencia de una marcada fábrica planar en los megacristales de microclina, conjuntamente con fenómenos de gradaciones en el tamaño de cristales, sineusis, alineaciones en los bordes de enclaves y aglomeraciones de cristales evidencian su origen temprano magmático. Los enclaves muestran una cinemática de deformación producida por cizalla simple.

  2. Asegurar la 'defensa y custodia' de las campañas: Vaquerías y diplomacia interétnica en las sierras pampeanas durante la primera mitad del siglo XVIII

    Directory of Open Access Journals (Sweden)

    Andrea Campetella

    2006-04-01

    Full Text Available El trabajo analiza un hecho que puede ser considerado el primer contacto diplomático oficial entre las autoridades de Buenos Aires y los indígenas de la pampa: el nombramiento, en febrero de 1717, de dos caciques que habitaban las serranías como Guardas Mayores para la "defensa y custodia" de las campañas. Para entender el motivo de este hecho sin precedentes se analizan los crecientes conflictos entre hispanocriollos por el acceso al ganado cimarrón y los intensos contactos en las serranías durante las décadas de transición del siglo XVII al XVIII donde convergían indígenas de diferentes regiones -incluyendo el área cordillerana- e hispanocriollos de diferentes jurisdicciones, todos ellos atraídos por la abundancia de ganado cimarrón. Finalmente, el trabajo ofrece una interpretación del nombramiento de los caciques en 1717 en función tanto de los intereses porteños como de los intereses indígenas.

  3. Contaminant studies in the Sierra Nevadas

    Science.gov (United States)

    Sparling, D.W.; Fellers, G.

    2002-01-01

    full text: Several species of anuran amphibians (frogs and toads) are experiencing severe population declines in even seemingly pristine areas of the Sierra Mountains of California. Among the most severely depressed species are the redlegged frog, the foothill and mountain yellow-legged frogs, the Yosemite toad, and the Cascades frog. Several factors, such as habitat fragmentation, introduced predators (especially fish), and disease, have been linked to these declines. But recent evidence from a USGS-led study shows that contaminants are a primary factor. During the past three years, researchers from the USGS Patuxent Wildlife Research Center, the Western Ecology Research Center, the USDA Beltsville Agriculture Research Center, and the Texas A&M University have teamed up to conduct an extensive study on airborne pesticides and their effects on amphibian populations in the Sierra Nevada Mountains. Previous work on environmental chemistry demonstrated that pesticides from the intensely agricultural Central Valley of California are being blown into the more pristine Sierra Nevada Mountains, especially around Sequoia and Yosemite National Parks. Several pesticides, including diazinon, chlorpyrifos, malathion and endosulfan, can be measured in snow, rainfall, and pond waters in these national parks. With the exception of endosulfan, these pesticides affect and even kill both invertebrates and vertebrate species by inhibiting cholinesterase, an enzyme essential to proper nervous system functioning. In the summer of 2001, we published a paper showing that these same pesticides are now found in adults and the tadpoles of Pacific treefrogs. The results of this landmark study showed that more than 50 percent of the tadpoles and adults sampled in Yosemite and Sequoia National Parks had detectable levels of diazinon or chlorpyrifos and that 86 percent of the Pacific treefrogs sampled in the Lake Tahoe region had detectable levels of endosulfan. In contrast, frogs that were

  4. Evaluación de la sequía 2008-2009 en el oeste de la Región Pampeana (Argentina

    Directory of Open Access Journals (Sweden)

    Guillermo T. D\\u2019Ambrosio

    2013-01-01

    Full Text Available Se analiza la variabilidad de la precipitación y los efectos de la sequía en la extensión areal del Dique Paso de las Piedras y en la actividad agrícola del Oeste de la región pampeana (Argentina durante los años 2008-2009. La metodología incluye la aplicación del Índice Estandarizado de Precipitación, el procesamiento digital de imágenes satelitales y el análisis de los rendimientos productivos de cuatro cultivos de la región. El Índice Estandarizado de Precipitación ha indicado sequía meteorológica en los años 2008 y 2009. En 2009 el rendimiento de los cultivos ha disminuido entre el 25 y 65 % con respecto a años anteriores. La extensión areal del dique ha disminuido un 52 % en 2009 en relación a períodos húmedos.

  5. Almanaques sí, relojes no. La prolongación de la jornada laboral en la agricultura pampeana, de la última dictadura al “boom” sojero

    Directory of Open Access Journals (Sweden)

    Juan Manuel Villulla

    2014-10-01

    Full Text Available Este artículo analiza los mecanismos económicos y dispositivos discursivos utilizados por las patronales para imponer la prolongación e intensificación de la jornada laboral en la agricultura pampeana, y sus consecuencias sobre las condiciones de trabajo de los obreros rurales luego de la década de 1970. La metodología incluyó la consulta de material bibliográfico especializado; fuentes documentales patronales (archivos de FACMA; sindicales (archivos de la CGT y UATRE; legislación laboral; libros de actas de negociaciones obrero-patronales (CNTA y CAR; material periodístico; y fundamentalmente un acervo testimonial recabado sobre una muestra de 50 obreros rurales y 20 empleadores en una serie de partidos arquetípicos del “boom” sojero de los últimos años en las provincias de Buenos Aires, Santa Fe y Córdoba. El resultado de nuestro análisis invita a incorporar como una de las condiciones de posibilidad para la expansión agrícola reciente al aumento de la explotación del trabajo asalariado

  6. Sobre la homogeinización de la presión fiscal en la agricultura pampeana tras la devaluación.

    Directory of Open Access Journals (Sweden)

    Diego Ariel Fernández

    2014-04-01

    Full Text Available La década del ’90 marcó una fuerte aceleración del proceso de concentración económica de la producción agrícola pampeana, evolución que continuaría tras la devaluación de 2002. En la determinación del mismo convergen distintos factores: las economías de escala, el manejo cambiario, la evolución tecnológica (entre otros. En este trabajo se estudia uno de estos condicionantes: la política impositiva del Estado Nacional. Se analizan los tributos que gravan al agro y sus alícuotas, diferenciando según la escala y perfil tecnológico del productor, calculando un indicador de la presión fiscal (peso de los tributos sobre el ingreso bruto de la explotación. Se concluye que en el nuevo siglo se produjo una nivelación importante en cuanto a los montos impositivos requeridos por el Estado a los distintos tipos de agentes, lo que minimizó la posibilidad que tiene éste a partir de aquella herramienta de modelar una trama social más desconcentrada.

  7. Ammonia at Blodgett Forest, Sierra Nevada, USA

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Marc L.; Littlejohn, David

    2007-11-06

    Ammonia is a reactive trace gas that is emitted in large quantities by animal agriculture and other sources in California, which subsequently forms aerosol particulate matter, potentially affecting visibility, climate, and human health. We performed initial measurements of NH{sub 3} at the Blodgett Forest Research Station (BFRS) during a two week study in June, 2006. The site is used for ongoing air quality research and is a relatively low-background site in the foothills of the Sierra Nevada. Measured NH{sub 3} mixing ratios were quite low (< 1 to {approx} 2 ppb), contrasting with typical conditions in many parts of the Central Valley. Eddy covariance measurements showed NH{sub 3} fluxes that scaled with measured NH{sub 3} mixing ratio and calculated aerodynamic deposition velocity, suggesting dry deposition is a significant loss mechanism for atmospheric NH{sub 3} at BFRS. A simple model of NH{sub 3} transport to the site supports the hypothesis that NH{sub 3} is transported from the Valley to BFRS, but deposits on vegetation during the summer. Further work is necessary to determine whether the results obtained in this study can be generalized to other seasons.

  8. Active shallow extension in central and eastern Betic Cordillera from CGPS data

    Science.gov (United States)

    Galindo-Zaldivar, J.; Gil, A. J.; Sanz de Galdeano, C.; Lacy, M. C.; García-Armenteros, J. A.; Ruano, P.; Ruiz, A. M.; Martínez-Martos, M.; Alfaro, P.

    2015-11-01

    The Betic Cordillera is an Alpine belt formed in the western Mediterranean by the westward displacement of the Alboran Domain in between the Eurasian and African convergent plates. New CGPS data from the central and eastern Betic Cordillera and its foreland-obtained mainly from the Topo-Iberia project-allowed us to precisely determine the rate of tectonic deformation. Most of the displacements of the central and eastern Betics are westward, with a variable southwestward component, in relation to the Eurasian stable plate. While in the Iberian foreland the displacements are extremely low, some deformation related to low compressional deformation occurs in the easternmost foreland basin and eastern Betic Cordillera. The displacement increases substantially southwards and westwards in relation to present-day extensional deformation. Major active discontinuities correspond to the NW-SE normal fault zones, which dip westwards; they are located in Almeria-Tabernas; Balanegra, and western Sierra de Gador; whereas the Padul fault zone located west of Sierra Nevada extends northwards to the Granada Basin. NW-SE extensional faults are also observed to the north, in the Baza Basin. Moreover, the activity of dextral faults along the Sorbas-Tabernas-Alpujarras-Guajares band, generally considered as a transfer fault zone, is evidenced by the displacement data. These results come to demonstrate the low activity or inactivity of the large northern E-W oriented folds of the central and eastern Internal Zone, such as the Sierra de Los Filabres antiform. They also point to the possible residual activity of the northern part of the NE-SW Sierra Nevada antiform, where the maximum relief of the Cordillera is found. Altogether, our data support a heterogeneous present-day westward extension that affects the upper crust of the Betic Cordillera and increases towards the thinned continental crust of the Alboran Sea and towards the west, which is compatible with roll-back subduction along

  9. Noteworthy records of two species of mammals in the Sierra Madre de Oaxaca, Mexico

    OpenAIRE

    2006-01-01

    We conducted mammal surveys in the Sierra Madre de Oaxaca (Sierra Norte) in Oaxaca, Mexico, and recorded the occurrence of two conspicuous mammal species: the spider monkey (Ateles geoffroyi vellerosus) and the coyote (Canis latrans cagottis). Spider monkeys has not been previously recorded in the Sierra Madre de Oaxaca, and coyotes have not been previously observed in Mexico at elevations as high as the present one (3 200 masl) in the Sierra Madre de Oaxaca

  10. La estructura del Grupo Sierras Bayas en el sector norte de las sierras homónimas, noroeste de las Sierras Septentrionales de Buenos Aires

    Directory of Open Access Journals (Sweden)

    A.C. Massabie

    2005-03-01

    Full Text Available El Grupo Sierras Bayas, de edad precámbrica tardía, se halla integrado por las formaciones sedimentarias Villa Mónica, Cerro Largo y Loma Negra, y forman parte de la porción noroccidental de las Sierras Septentrionales de Buenos Aires. Los afloramientos principales, relativamente aislados en serranías bajas, se ubican en los alrededores de Olavarría, particularmente en las Sierras Bayas, y con menor extensión en cercanías a la localidad de Barker. La morfoestructura de conjunto de estas sedimentitas en el sector norte de las Sierras Bayas corresponde a una cubeta asimétrica levemente basculada hacia el sudsudoeste. En el Grupo Sierras Bayas, se han identificado y relevado sistemáticamente dos sistemas de plegamiento suave F1 (NE y F2 (NO que se interfieren y generan diseños de tipo 1 en domos y cubetas. Los plegamientos reconocidos, F1 y F2, de planos axiales subverticales y ejes B subhorizontales se interfieren con ángulos que varían entre 70º y 90º. Desarrollan tres órdenes de plegamiento que controlan en las escalas adoptadas para el mapeo, la posición de los afloramientos y exposiciones artificiales de las formaciones integrantes del Grupo Sierras Bayas. El fallamiento local relevado ejerce un control muy limitado sobre la disposición de las sedimentitas precámbricas plegadas, y las observaciones de campo avalan su actividad inicial con posterioridad al episodio tectónico que desarrolló los sistemas de plegamiento del Grupo Sierras Bayas. La deformación dúctil de la cubierta sedimentaria, como ha sido observado localmente, se considera que ha estado asociada con una reactivación tectónica del basamento, Complejo Buenos Aires, favorecida por las anisotropías penetrativas principales preexistentes en el macizo rocoso de granititas milonitizadas. La similitud en el diseño de los plegamientos F1 y F2, la morfoestructura general en cubeta y la falta de una secuencia definida en las relaciones de interferencia permitir

  11. SIERRA - A 3-D device simulator for reliability modeling

    Science.gov (United States)

    Chern, Jue-Hsien; Arledge, Lawrence A., Jr.; Yang, Ping; Maeda, John T.

    1989-05-01

    SIERRA is a three-dimensional general-purpose semiconductor-device simulation program which serves as a foundation for investigating integrated-circuit (IC) device and reliability issues. This program solves the Poisson and continuity equations in silicon under dc, transient, and small-signal conditions. Executing on a vector/parallel minisupercomputer, SIERRA utilizes a matrix solver which uses an incomplete LU (ILU) preconditioned conjugate gradient square (CGS, BCG) method. The ILU-CGS method provides a good compromise between memory size and convergence rate. The authors have observed a 5x to 7x speedup over standard direct methods in simulations of transient problems containing highly coupled Poisson and continuity equations such as those found in reliability-oriented simulations. The application of SIERRA to parasitic CMOS latchup and dynamic random-access memory single-event-upset studies is described.

  12. Compuestas medicinales de la provincia biogeográfica pampeana: claves para su determinación e iconografías : Parte 1: compuestas espinosas (grupo 1) y compuestas con tallos alados (grupo 2)

    OpenAIRE

    Freire, Susana E.; Urtubey, Estrella

    1999-01-01

    En la provincia biogeográfica Pampeana (este de la Argentina, Uruguay y la mitad austral de Río Grande do Sul en Brasil) se encuentran 154 especies y 12 variedades de Compuestas con propiedades medicinales. Con el objeto de facilitar la identificación de las especies, las mismas se dividieron en siete grupos artificiales: 1. Compuestas espinosas (con espinas en tallos, hojas y10 filarios); 2. Compuestas con tallos alados; 3. Compuestas con capítulos isomorfos y papus piloso; 4. Compuestas ...

  13. Compuestas medicinales de la provincia biogeográfica pampeana: claves para su determinación e iconografías : Parte II: compuestas con capítulos isomorfos y papus piloso (grupo 3)

    OpenAIRE

    Freire, Susana E.; Urtubey, Estrella

    1999-01-01

    El presente trabajo representa la segunda prte de las Compuestas medicinales de la provincia biogeográfica Pampeana (este de la Argentina, Uruguay y mitad austral de Río Grande do Sul en Brasil), ubicadas en el tercer grupo artificial de los siete delimitados en la primera parte del trabajo. El grupo 3 está caracterizado por sus capítulos con flores isomorfas y papus piloso. Comprende 53 taxones, pertenecientes a siete tribus: Astereae (Baccharis), Cichorieae (Chondriila, Hypochaeris, Lactuca...

  14. Tectonic activity revealed by morphostructural analysis: Development of the Sierra de la Candelaria range, northwestern Argentina

    Science.gov (United States)

    Barcelona, H.; Peri, G.; Tobal, J.; Sagripanti, L.; Favetto, A.

    2014-12-01

    The tectonically active broken foreland of NW Argentina is a recent analog of the eastern margin of the Puna plateau during Mio-Pliocene times and likely of other broken forelands worldwide. In order to evaluate active tectonism in the broken foreland of the NW Argentine Andes, we examined the complex geomorphology in the vicinity of the basement-cored Sierra de la Candelaria range at ˜26°S and deciphered multiple episodes of crustal deformation spanning the Pliocene to the Quaternary. Digital elevation models, satellite images and geological data within a GIS environment allowed us to analyze the terrain, drainage networks, river dynamics and structure, as well as to obtain detailed geomorphological mapping, active tectonic indices, longitudinal river profiles and structural sections. Three morphostructural segments were defined based on the structural features, the differential vertical dissection pattern over the basement, the faulted Pliocene to recent deposits, the stepwise propagation of anticlines and the distortion over the fluvial system. By combining the several lines of evidence, we concluded that the Sierra de la Candelaria range was subjected to a multi-stage development. The first stage uplifted the central segment concomitant with the formation of the surrounding ranges and with the main partition phase of the foreland. After a significant time lapse, the mountain range was subjected to southward thick-skinned growth and northward growth via stepwise thin-skinned deformation and exerted control over the dynamics of the Río Rosario. Taking into account the surrounding basins and ranges of the Sierra de la Candelaria, the southern Santa Bárbara System is characterized by partially isolated intramontane basins (Choromoro and Rosario) limited by shielded ranges that caused moisture block and shows continuous deformation. These features were related to early stages of a broken foreland evolution model and modern analogs were found at the northern

  15. Recent large fold nucleation in the upper crust: Insight from gravity, magnetic, magnetotelluric and seismicity data (Sierra de Los Filabres-Sierra de Las Estancias, Internal Zones, Betic Cordillera)

    Science.gov (United States)

    Pedrera, Antonio; Galindo-Zaldívar, Jesús; Ruíz-Constán, Ana; Duque, Carlos; Marín-Lechado, Carlos; Serrano, Inmaculada

    2009-01-01

    Rheological heterogeneities in the upper-crust have a close relationship with the fold position where rigid bodies could constitute initial perturbations that allow the nucleation of folds. Consequently, establish the position and geometry of anomalous rocks located in the upper-crust by geophysical studies help to understand the folded structure observed on surface. New geological observations in the field, along with gravity, magnetic, magnetotelluric and seismicity data, reveal the subsurface structure in the Sierra de Los Filabres-Sierra de Las Estancias folded region part of the Alpine belt in southern Spain. The geometry of the upper crust is determined by geological field data, 2D gravity models, 2D magnetic models and 2D MT resistivity model, while seismicity evidences the location of the deep active structures. These results allow us to propose that a basic rock body at 4 to 9 km depth has determined the nucleation and development of the Sierra de Los Filabres kilometric antiform. N-vergent large late folds are subjected to a variable present-day stress field. Earthquake focal mechanisms suggest the presence in depth of a regional NW-SE compressive stress field. However, most of the seismogenetic structures do not extend up to the surface, where NW-SE and WNW-ESE outcropping active normal faults are observed, thus indicating a NE-SW extension in the upper crust simultaneous to orthogonal NW-SE compression related to reverse faults and minor folds developed in the Eastern Almanzora Corridor and in the nearby Huércal-Overa Basin. The recent and active tectonic studies of cordilleras hinterland subjected to late folding greatly benefits from the integration of surface observations together with geophysical data.

  16. Ecología de la fauna silvestre de la sierra nevada y la Sierra del Ajusco

    OpenAIRE

    M. A. Hernández García; Sánchez González, A; D. Granados Sánchez; G. F. López Ríos

    2004-01-01

    Se presenta un estudio sobre la fauna silvestre de la Sierra del Ajusco y la Sierra Nevada, localizadas dentro de la Faja Volcánica Transmexicana (FVT), en la porción oriental del límite meridional de la Cuenca de México. La enorme riqueza biológica de esta zona que rodea la zona metropolitana de la ciudad de México, uno de los mayores complejos urbanos del mundo, ha sobrevivido durante décadas al impacto de la urbanización de las áreas forestales, explotación de recursos naturales, contamina...

  17. Sierra/solid mechanics 4.22 user's guide.

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Jesse David

    2011-10-01

    Sierra/SolidMechanics (Sierra/SM) is a Lagrangian, three-dimensional code for the analysis of solids and structures. It provides capabilities for explicit dynamic and implicit quasistatic and dynamic analyses. The explicit dynamics capabilities allow for the efficient and robust solution of models subjected to large, suddenly applied loads. For implicit problems, Sierra/SM uses a multi-level iterative solver, which enables it to effectively solve problems with large deformations, nonlinear material behavior, and contact. Sierra/SM has a versatile library of continuum and structural elements, and an extensive library of material models. The code is written for parallel computing environments, and it allows for scalable solutions of very large problems for both implicit and explicit analyses. It is built on the SIERRA Framework, which allows for coupling with other SIERRA mechanics codes. This document describes the functionality and input structure for Sierra/SM.

  18. El continuo trato con infieles: los renegados de la región pampeana centro-oriental durante el último tercio del siglo XVIII

    Directory of Open Access Journals (Sweden)

    Daniel Villar

    2005-12-01

    Full Text Available Se considera el caso de los renegados, un conjunto poco numeroso de criollos, mestizos, negros y mulatos voluntariamente instalados entre los grupos indígenas de la región pampeana centro-oriental. Acogidos con flexibilidad por estos últimos, que los incorporaban a su vida y proyectos, los renegados representaron, en cambio, para la administración colonial la figura del traidor por antonomasia, totalmente volcados a auxiliar a los infieles para lo cual previamente debieron apartarse de dios y abandonar al rey, convirtiéndose en seres irredimibles y peligrosos. Una serie de diacríticos que revelaban su singular condición transcultural contribuyeron a aumentar el grado de exposición al riesgoimplicado por su actividad como espías y baqueanos, y al tiempo que facilitaron su identificación y castigo, les confirieron una visibilidad documental que permite reflexionar sobre el contexto de mixegenación cultural 1 en el que sus presencias cobran sentido.The subject matter is the renegadoes, a small group of criollos, mestizos, black men and mulattoes, voluntarily settled among the indigenous groups of the central-west region of the pampas. Received with flexibility by the latter, who incorporated them into their lives and projects, the renegadoes were seen as absolute traitors by the colonial administration since, after abandoning the Christian god and king, they dedicated themselves to helping the unfaithful becoming irredeemable and dangerous beings. A series of diacritics, that revealed their unique transcultural condition, contributed to increase the risk exposure implied by their activities as spies and scouts (baqueanos, facilitating their identification and punishment and also granting them a documentary visibility that allows us to think about the cultural miscegenation context in which their presence became significant.

  19. Sequías agrícolas: recurrencia, clasificación y distribución en la Región Pampeana argentina

    Directory of Open Access Journals (Sweden)

    Olga Eugenia Scarpati

    2016-01-01

    Full Text Available Las sequías, fenómeno de alta frecuencia en la Región Pampeana (Argentina, se estudian a través de un índice agrometeorológico derivado del balance de agua del suelo, con lo que se presenta un aporte diferente a la bibliografía del tema. Se considera como índice de los eventos, el valor anual del déficit de agua en el suelo. Ellos tienen lugar casi todos los años, si no en la totalidad del territorio, en algún área y espacio temporal. Las consiguientes consecuencias son diversas en su gravedad, pero siempre tienen impactos socioeconómicos. La evolución y distribución de los sucesos acaecidos se analizan y se realiza la correspondiente climatología. En el estudio se han utilizado datos diarios de precipitación del Servicio Meteorológico Nacional del período 1950 – 2010; evapotranspiración potencial media diaria según la fórmula de Penman- Monteith; balance de agua en el suelo considerando las características del suelo obtenidas «in situ»; y la aplicación de los tests estadísticos no paramétricos Mann-Kendall y Sen. Las series anuales del índice agrometeorológico se emplean para clasificar de la severidad de los eventos en leves, moderados, severos y fuertes y se estudia la tendencia para cada localidad y diferentes lapsos de tiempo.

  20. Diversidad y distribución de acridios (Orthoptera: Acridoidea en pastizales del sur de la región pampeana, Argentina

    Directory of Open Access Journals (Sweden)

    Yanina Mariottini

    2013-03-01

    Full Text Available Los acridios son componentes nativos de los pastizales, dichos sistemas han sido modificados debido a la intensificación de las actividades agrícola-ganaderas y por lo tanto se considera importante estudiar las comunidades de acridios asociadas. Se estudió la diversidad y distribución de acridios en el Sur de la región pampeana a través de muestreos realizados en las comunidades vegetales más representativas del partido de Laprida, provincia de Buenos Aires, durante cinco temporadas (2005-2010. Se recolectaron 22 especies. La subfamilia Melanoplinae fue la más diversa (ocho especies. La mayor cantidad de especies se observó en los pastizales nativos (18. La diversidad en los pastizales alterados (1.75±0.096 fue superior (p<0.05 a la de los pastizales halófilos (1.34±0.12. La riqueza de plantas en los pastizales nativos y los pastizales alterados fue superior (p<0.05 a la de las demás comunidades. Se registro una relación positiva entre la riqueza de plantas y las variables riqueza y diversidad de acridios. La similitud entre las comunidades de acridios estimada por los índices cualitativos fue superior al 60%. En general, las especies que tuvieron una mayor frecuencia de aparición, mostraron una mayor abundancia y distribución. Covasacris pallidinota, Dichroplus elongatus, D. maculipennis, Borellia bruneri y B. pallida fueron las de mayor distribución, cinco especies tuvieron una distribución intermedia y la mayoría (12 una distribución restringida.

  1. 75 FR 76975 - 2015 Resource Pool-Sierra Nevada Region

    Science.gov (United States)

    2010-12-10

    ... allocations pursuant to its 2004 Power Marketing Plan (Marketing Plan) for the Sierra Nevada Customer Service... its Marketing Plan for SNR in the Federal Register (64 FR 34417, June 25, 1999). The Marketing Plan... Washoe Project beginning January 1, 2005, and continuing through December 31, 2024. The Marketing Plan...

  2. The Sierra Club--A History. Part 2: Conservation

    Science.gov (United States)

    Strong, Douglas H.

    1977-01-01

    This second article on Sierra Club history brings the Club into the 1960s. It relates early conservation activities of the club, such as the efforts to save the Hetch Hetchy Valley. The campaign against construction of a dam in Dinosaur National Monument helped establish the club as a national organization. (MA)

  3. Library Education and the Practitioner: The Sierra Leone Experience.

    Science.gov (United States)

    Kargbo, John Abdul

    1999-01-01

    Examines the past and current educational trends of librarianship in Sierra Leone. Discuses courses offered in the current library school; economic and political issues affecting higher education; the need for full-time faculty; general versus specialized practitioner needs; attitudes of faculty toward working librarians; and professional…

  4. School-Based Peace Building in Sierra Leone

    Science.gov (United States)

    Bretherton, Diane; Weston, Jane; Zbar, Vic

    2005-01-01

    This article describes the development of a peace education project, including the Peace Education Kit, in schools in Sierra Leone. The program, initiated by the World Bank, has involved working partnerships between local and international agencies and provides a case study of how schools can work with the community to contribute to a national…

  5. Life in Sierra Leone, West Africa. A Teaching Unit.

    Science.gov (United States)

    Corby, Richard A.

    This unit is designed for students in grades 6-12. The unit provides an introduction to Sierra Leone and the continent of Africa through basic concepts and a conceptual framework for learning. The unit is divided into 17 activities. Activities include: (1) "Stereotypes and Myths about African and Africans"; (2) "The Manding Name…

  6. School Libraries in Sierra Leone's Educational System: Quo Vadis?

    Science.gov (United States)

    Kargbo, John A.

    2003-01-01

    Examines the role of school libraries in Sierra Leone's (Africa) educational system and the problems affecting their development. Discusses the need for materials to support teaching activities; sociological factors; teachers' and students' information needs; current trends and changes; rural areas with no school libraries; and lack of standards,…

  7. Power in Practice: Trade Union Education in Sierra Leone

    Science.gov (United States)

    Stirling, John

    2013-01-01

    This article presents an analysis of the development of a trade union education program in Sierra Leone in the geo-historical context of British colonialism. It places the argument in relation to the contradictory trends of trade unionism more generally and alongside their antagonistic cooperation with capitalism. It discusses the limits and…

  8. A New Agenda for Adult Education in Sierra Leone.

    Science.gov (United States)

    Skelt, Joanna

    2003-01-01

    After years of conflict, Sierra Leone has critical educational development needs including trauma healing and conflict resolution, rebuilding of the educational infrastructure, and citizenship and capacity building. Citizenship education in this context must be redefined as developing individual agency and encouraging active participation. (SK)

  9. Catastrophic rockfalls and rockslides in the Sierra Nevada, USA

    Science.gov (United States)

    Wieczorek, Gerald F.; Evans, Stephen G.; DeGraff, Jerome V.

    2002-01-01

    Despite having a low recorded historical incidence of landsliding, the Sierra Nevada has undergone large prehistoric and historical rockfalls and rockslides that could be potentially catastrophic if they occurred today in the more densely populated parts of the region. Several large documented rockfall and rockslides have been triggered either by strong seismic shaking or long periods of unusually wet weather; however, in several instances no obvious triggering event can be identified. The glaciated topography of the higher elevations of the SierraNevada has produced many relatively small falls and slides within relatively hard, massively jointed, granitic rocks; however, where exposed to weathering for long periods after glaciation, the oversteepened rock slopes are prone to uncommonly large falls and slides. At lower elevations on the nonglaciated slopes of the Sierra Nevada, rockslides commonly occur within more weathered granitic rocks, where the strength of the rock mass is typically affected by joint weathering and alteration of the intact rock to saprolite. Historical large rock-falls and rockslides in the Sierra Nevada have created additional secondary natural hazards, including debris flows and floods from the breaching of landslide dams that can be as hazardous as the initial rockfalls and rockslides.

  10. An accidental sect: how war made belief in Sierra Leone

    NARCIS (Netherlands)

    Richards, P.

    2006-01-01

    Idealists consider beliefs cause wars. Realists consider wars cause beliefs. The war in Sierra Leone offers some scope to test between these two views. The main rebel faction, the Revolutionary United Front (RUF) was, sociologically speaking, an accidental sect. It lost its original ideologues at an

  11. Color and 3D views of the Sierra Nevada mountains

    Science.gov (United States)

    2002-01-01

    A stereo 'anaglyph' created using the nadir and 45.6-degree forward-viewing cameras provides a three-dimensional view of the scene when viewed with red/blue glasses. The red filter should be placed over your left eye. To facilitate the stereo viewing, the images have been oriented with north toward the left. Some prominent features are Mono Lake, in the center of the image; Walker Lake, to its left; and Lake Tahoe, near the lower left. This view of the Sierra Nevadas includes Yosemite, Kings Canyon, and Sequoia National Parks. Mount Whitney, the highest peak in the contiguous 48 states (elev. 14,495 feet), is visible near the righthand edge. Above it (to the east), the Owens Valley shows up prominently between the Sierra Nevada and Inyo ranges. Precipitation falling as rain or snow on the Sierras feeds numerous rivers flowing southwestward into the San Joaquin Valley. The abundant fields of this productive agricultural area can be seen along the lower right; a large number of reservoirs that supply water for crop irrigation are apparent in the western foothills of the Sierras. Urban areas in the valley appear as gray patches; among the California cities that are visible are Fresno, Merced, and Modesto.

  12. Structural Evolution of the East Sierra Valley System (Owens Valley and Vicinity, California: A Geologic and Geophysical Synthesis

    Directory of Open Access Journals (Sweden)

    Richard J. Blakely

    2013-04-01

    Full Text Available The tectonically active East Sierra Valley System (ESVS, which comprises the westernmost part of the Walker Lane-Eastern California Shear Zone, marks the boundary between the highly extended Basin and Range Province and the largely coherent Sierra Nevada-Great Valley microplate (SN-GVm, which is moving relatively NW. The recent history of the ESVS is characterized by oblique extension partitioned between NNW-striking normal and strike-slip faults oriented at an angle to the more northwesterly relative motion of the SN-GVm. Spatially variable extension and right-lateral shear have resulted in a longitudinally segmented valley system composed of diverse geomorphic and structural elements, including a discontinuous series of deep basins detected through analysis of isostatic gravity anomalies. Extension in the ESVS probably began in the middle Miocene in response to initial westward movement of the SN-GVm relative to the Colorado Plateau. At ca. 3–3.5 Ma, the SN-GVm became structurally separated from blocks directly to the east, resulting in significant basin-forming deformation in the ESVS. We propose a structural model that links high-angle normal faulting in the ESVS with coeval low-angle detachment faulting in adjacent areas to the east.

  13. Structure and regional significance of the Late Permian(?) Sierra Nevada - Death Valley thrust system, east-central California

    Science.gov (United States)

    Stevens, C.H.; Stone, P.

    2005-01-01

    An imbricate system of north-trending, east-directed thrust faults of late Early Permian to middle Early Triassic (most likely Late Permian) age forms a belt in east-central California extending from the Mount Morrison roof pendant in the eastern Sierra Nevada to Death Valley. Six major thrust faults typically with a spacing of 15-20 km, original dips probably of 25-35??, and stratigraphic throws of 2-5 km compose this structural belt, which we call the Sierra Nevada-Death Valley thrust system. These thrusts presumably merge into a de??collement at depth, perhaps at the contact with crystalline basement, the position of which is unknown. We interpret the deformation that produced these thrusts to have been related to the initiation of convergent plate motion along a southeast-trending continental margin segment probably formed by Pennsylvanian transform truncation. This deformation apparently represents a period of tectonic transition to full-scale convergence and arc magmatism along the continental margin beginning in the Late Triassic in central California. ?? 2005 Elsevier B.V. All rights reserved.

  14. Health complications of female genital mutilation in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Bjälkander O

    2012-07-01

    Full Text Available Owolabi Bjälkander,1 Laurel Bangura,2 Bailah Leigh,3 Vanja Berggren,1 Staffan Bergström,1 Lars Almroth11Division of Global Health, Department of Public Health, Karolinska Institutet, Stockholm, Sweden; 2Inter Africa Committee, Sierra Leone; 3Department of Community Health, College of Medicine and Allied Health Sciences, University of Sierra Leone, Sierra LeoneAbstract: Sierra Leone has one of the highest rates of female genital mutilation (FGM in the world, and yet little is known about the health consequences of the practice.Purpose: To explore whether and what kind of FGM-related health complications girls and women in Sierra Leone experience, and to elucidate their health care-seeking behaviors.Patients and methods: A feasibility study was conducted to test and refine questionnaires and methods used for this study. Thereafter, a cross-section of girls and women (n = 258 attending antenatal care and Well Women Clinics in Bo Town, Bo District, in the southern region and in Makeni Town, Bombali District, in the northern region of Sierra Leone were randomly selected. Participants answered interview-administrated pretested structured questionnaires with open-ended-questions, administrated by trained female personnel.Results: All respondents had undergone FGM, most between 10 and 14 years of age. Complications were reported by 218 respondents (84.5%, the most common ones being excessive bleeding, delay in or incomplete healing, and tenderness. Fever was significantly more often reported by girls who had undergone FGM before 10 years of age compared with those who had undergone the procedure later. Out of those who reported complications, 187 (85.8% sought treatment, with 89 of them visiting a traditional healer, 75 a Sowei (traditional circumciser, and 16 a health professional.Conclusion: The high prevalence rate of FGM and the proportion of medical complications show that FGM is a matter for public health concern in Sierra Leone. Girls who

  15. Lassa Fever in Post-Conflict Sierra Leone

    Science.gov (United States)

    Hartnett, Jessica N.; Levy, Danielle C.; Yenni, Rachael E.; Moses, Lina M.; Fullah, Mohammed; Momoh, Mambo; Fonnie, Mbalu; Fonnie, Richard; Kanneh, Lansana; Koroma, Veronica J.; Kargbo, Kandeh; Ottomassathien, Darin; Muncy, Ivana J.; Jones, Abigail B.; Illick, Megan M.; Kulakosky, Peter C.; Haislip, Allyson M.; Bishop, Christopher M.; Elliot, Deborah H.; Brown, Bethany L.; Zhu, Hu; Hastie, Kathryn M.; Andersen, Kristian G.; Gire, Stephen K.; Tabrizi, Shervin; Tariyal, Ridhi; Stremlau, Mathew; Matschiner, Alex; Sampey, Darryl B.; Spence, Jennifer S.; Cross, Robert W.; Geisbert, Joan B.; Folarin, Onikepe A.; Happi, Christian T.; Pitts, Kelly R.; Geske, F. Jon; Geisbert, Thomas W.; Saphire, Erica Ollmann; Robinson, James E.; Wilson, Russell B.; Sabeti, Pardis C.; Henderson, Lee A.; Khan, S. Humarr; Bausch, Daniel G.; Branco, Luis M.; Garry, Robert F.

    2014-01-01

    Background Lassa fever (LF), an often-fatal hemorrhagic disease caused by Lassa virus (LASV), is a major public health threat in West Africa. When the violent civil conflict in Sierra Leone (1991 to 2002) ended, an international consortium assisted in restoration of the LF program at Kenema Government Hospital (KGH) in an area with the world's highest incidence of the disease. Methodology/Principal Findings Clinical and laboratory records of patients presenting to the KGH Lassa Ward in the post-conflict period were organized electronically. Recombinant antigen-based LF immunoassays were used to assess LASV antigenemia and LASV-specific antibodies in patients who met criteria for suspected LF. KGH has been reestablished as a center for LF treatment and research, with over 500 suspected cases now presenting yearly. Higher case fatality rates (CFRs) in LF patients were observed compared to studies conducted prior to the civil conflict. Different criteria for defining LF stages and differences in sensitivity of assays likely account for these differences. The highest incidence of LF in Sierra Leone was observed during the dry season. LF cases were observed in ten of Sierra Leone's thirteen districts, with numerous cases from outside the traditional endemic zone. Deaths in patients presenting with LASV antigenemia were skewed towards individuals less than 29 years of age. Women self-reporting as pregnant were significantly overrepresented among LASV antigenemic patients. The CFR of ribavirin-treated patients presenting early in acute infection was lower than in untreated subjects. Conclusions/Significance Lassa fever remains a major public health threat in Sierra Leone. Outreach activities should expand because LF may be more widespread in Sierra Leone than previously recognized. Enhanced case finding to ensure rapid diagnosis and treatment is imperative to reduce mortality. Even with ribavirin treatment, there was a high rate of fatalities underscoring the need to

  16. Lassa fever in post-conflict sierra leone.

    Directory of Open Access Journals (Sweden)

    Jeffrey G Shaffer

    2014-03-01

    Full Text Available Lassa fever (LF, an often-fatal hemorrhagic disease caused by Lassa virus (LASV, is a major public health threat in West Africa. When the violent civil conflict in Sierra Leone (1991 to 2002 ended, an international consortium assisted in restoration of the LF program at Kenema Government Hospital (KGH in an area with the world's highest incidence of the disease.Clinical and laboratory records of patients presenting to the KGH Lassa Ward in the post-conflict period were organized electronically. Recombinant antigen-based LF immunoassays were used to assess LASV antigenemia and LASV-specific antibodies in patients who met criteria for suspected LF. KGH has been reestablished as a center for LF treatment and research, with over 500 suspected cases now presenting yearly. Higher case fatality rates (CFRs in LF patients were observed compared to studies conducted prior to the civil conflict. Different criteria for defining LF stages and differences in sensitivity of assays likely account for these differences. The highest incidence of LF in Sierra Leone was observed during the dry season. LF cases were observed in ten of Sierra Leone's thirteen districts, with numerous cases from outside the traditional endemic zone. Deaths in patients presenting with LASV antigenemia were skewed towards individuals less than 29 years of age. Women self-reporting as pregnant were significantly overrepresented among LASV antigenemic patients. The CFR of ribavirin-treated patients presenting early in acute infection was lower than in untreated subjects.Lassa fever remains a major public health threat in Sierra Leone. Outreach activities should expand because LF may be more widespread in Sierra Leone than previously recognized. Enhanced case finding to ensure rapid diagnosis and treatment is imperative to reduce mortality. Even with ribavirin treatment, there was a high rate of fatalities underscoring the need to develop more effective and/or supplemental treatments for

  17. The Current Outbreak of Ebola virus is still Continue in Guinea, Liberia and Sierra Leone: A Fact Sheet

    Directory of Open Access Journals (Sweden)

    Tauseef Ahmad

    2015-01-01

    Full Text Available The current outbreak of the Ebola virus occurred in the West Africa and it is the largest and more lethal outbreak in the history of Ebola virus. Thousands of peoples were infected along with thousands of death. The first case of current outbreak of Ebola virus was reported from Guine and acute;e Forestie` re (Forested Guinea, eastern area of Guinea in December 2013 (Ahmad, 2014; Baize et al., 2014; Gatherer, 2014. But in March 2014 the diseases spread so much fast and infected the surrounding countries Liberia and Sierra Leone. While in August 2014 the Ebola virus were reported from the Nigeria (Ahmad, 2014. [Biomed Res Ther 2015; 2(1.000: 193-195

  18. La estructura del Grupo Sierras Bayas en el sector norte de las sierras homónimas, noroeste de las Sierras Septentrionales de Buenos Aires The structure of Sierras Bayas Group in the north area of the homonymous hills, northwest of Sierras Septentrionales of Buenos Aires, Argentine

    OpenAIRE

    A.C. Massabie; O.E. Nestiero

    2005-01-01

    El Grupo Sierras Bayas, de edad precámbrica tardía, se halla integrado por las formaciones sedimentarias Villa Mónica, Cerro Largo y Loma Negra, y forman parte de la porción noroccidental de las Sierras Septentrionales de Buenos Aires. Los afloramientos principales, relativamente aislados en serranías bajas, se ubican en los alrededores de Olavarría, particularmente en las Sierras Bayas, y con menor extensión en cercanías a la localidad de Barker. La morfoestructura de conjunto de estas sedim...

  19. La estructura del área de Sierra Espuña (contacto zonas internas-externas, sector oriental de la Cordillera Bética

    Directory of Open Access Journals (Sweden)

    A., Martín-Algarra

    1997-12-01

    Full Text Available Sierra Espuña is located in the Eastern Betic Cordillera. The contact between the Malaguide Complex (Internal Betic Zone and the External Betic Zone cropouts in this area. Sierra Espuña area is a great antiformal stack that is followed by a great synforme (Mula-Pliego Depression. In the upper part of the Malaguide Complex, two nappes, with numerous internal folding and minor thrusting, are recognized: the Morron de Totana Nappe (at the bottom and the Perona Nappe (at the top. This structure is the result of a complex polyphasic tectonics in which two main structural events are recognized: the Intraoligocene tectonic phase, and the Lower Miocene tectonic phase.Sierra Espuña se sitúa en el sector oriental de la Cordillera Bética. En este sector afloran principalmente terrenos pertenecientes al Complejo Maláguide (Zonas Internas Béticas en contacto con las Zonas Externas Béticas. Esta región se configura como un gran antiforme de mantos al S (Sierra Espuña, seguido al N por un gran sinforme (Depresión de Mula-Pliego. En la parte alta del complejo, se reconocen dos unidades con el rango de manto de corrimiento, con numerosos repliegues y escamaciones internas: el Manto de Morrón de Totana, en posición inferior, y el Manto de Perona, en posición superior. Esta estructura es el resultado de una tectónica polifásica muy compleja en la que se reconocen dos grandes eventos estructurales: la fase tectónica Intraoligocena, y la fase tectónica del Mioceno Inferior.

  20. La susceptibilidad magnética del batolito de Achala (Devónico, Sierra Grande de Córdoba y sus diferencias con otros granitos achalianos

    Directory of Open Access Journals (Sweden)

    Silvana E. Geuna

    2008-09-01

    Full Text Available El magmatismo devónico de las Sierras Pampeanas de Córdoba y San Luis está representado por batolitos y plutones de composición monzogranítica y forma subelíptica, emplazados en un basamento metamórfico-plutónico eopaleozoico. Se distinguen dos grupos: el primero, compuesto por granitoides con hornblenda-biotita, metaluminosos a débilmente peraluminosos; y el segundo, formado por granitoides con biotita y muscovita, peraluminosos. Ambos grupos se caracterizan respectivamente por tener magnetita e ilmenita como fases accesorias, lo cual genera propiedades magnéticas distintivas. Entre ellos, el batolito de Achala, Córdoba, con una extensión de casi 2.500 km², es un buen exponente de los granitos paramagnéticos (no magnéticos. Su mineralogía magnética fue caracterizada en cuarenta y un sitios, la mayoría de ellos en el Monzogranito Achala. Se determinó una susceptibilidad magnética promedio muy baja, 15 x 10-5 (SI, controlada por el contenido de biotita e ilmeno- hematita. Veintiún sitios mostraron remanencia magnética estable portada por hematita, que aparece como un mineral accesorio, intercrecida con discos de exsolución de (hemoilmenita. La anisotropía de susceptibilidad magnética es débil y predominan las formas obladas, como es usual en fábricas magmáticas de granitos paramagnéticos; casi no se obtuvieron lineaciones. El grado de anisotropía es mayor en zonas con cizallamiento magmático, debido al efecto de la deformación subsolidus. El magnetismo débil del monzogranito de Achala contrasta con el carácter magnético de los plutones monzograníticos porfíricos más representativos de otros batolitos de la región, como Renca, Cerro Áspero y Las Chacras-Piedras Coloradas. La virtual ausencia de magnetita, junto con la presencia de ilmeno-hematita exsuelta, indica que un enfriamiento bajo condiciones oxidantes sería el responsable del carácter paramagnético de Achala. Como consecuencia de aplicación pr

  1. Rangewide glaciation in the Sierra Nevada, California

    Science.gov (United States)

    Moore, James G.; Moring, Barry C.

    2013-01-01

    The 600-km-long Sierra Nevada underwent extensive Pleistocene glaciation except for its southernmost 100 km. Presently, ∼1700 small glaciers and ice masses near the crest of the range occur above 3250 m in elevation; these covered an area of ∼50 km2 in 1972. Fourteen of the largest glaciers decreased by about one half in area during the period from 1900 to 2004. Rock glaciers, generally glacial ice covered by 1–10 m of rockfall debris, occur in about the same span of the range as ice and permanent snowfields. They are, on average, lower by 200–300 m, apparently because of the insulating layer of rocky rubble that protects their internal ice from the sun’s heat and from wind. The principal Pleistocene glacial stages are the Sherwin (ca. 820 ka), Tahoe (170–130 and ca. 70 ka), Tioga (14–28 ka), and Recess Peak (13 ka). Some 7040 glacial lakes, produced primarily by quarrying from bedrock, were mostly exposed after recession of the Tioga glacial stage. The lakes largely mark the area of primary snow accumulation. Below the lower limit of the lakes, ice flowed downward into river-cut canyons, forming major trunk glaciers within the zone of ablation. The range is in general a westward-tilted block upfaulted on its east side. Therefore, the main late Pleistocene trunk glaciers (Tahoe/Tioga) west of the crest extend 25–60 km, whereas those east of the crest extend only 5–20 km. Because of higher precipitation northward, glacial features such as the toes of existing glaciers and rock glaciers, as well as the late season present-day snowline, all decrease in elevation northward. Likewise, the elevation of the lower limit of glacial lakes, an indication of the zone of snow accumulation during the late Pleistocene, decreases about the same degree. This similarity suggests that the overall climate patterns of the late Pleistocene, though cooler, were similar to those of today. The east slope glaciers show a similar northward depression, but they are ∼500

  2. Petrología y análisis geométrico y tectónico de las milonitas de la Sierra de Copacabaña, provincia de Catamarca, República Argentina

    Directory of Open Access Journals (Sweden)

    López, J. P.

    1992-12-01

    Full Text Available A petrographic and structural study of units from Copacabana Range in the Northwestern Pampean Ranges is presented. Two facies of deformed granitoids were recognized. Rocks of both facies are classificated as mylonite schists, mylonite gneisses and protomylonites. First would have formed at temperature of 3500 C and 15 km of deep. Protomylonite would have formed at lower temperatures and deeps. Undeformed granitoids and ortogneis are also descript.Structural data and the analysis of some kinematic indicators suggest that a main shear plane strikes NNW, inclined to the east, with vergence to the west. Geometric analysis, realized in base to petrographic diagrams of c-axis of quartz and mica cleavage suggest an orthorhombic fabric.Se realiza un estudio petrológico estructural de las unidades que componen el extremo septentrional de la Sierra de Copacabana, que se localiza en el ámbito de las Sierras Pampeanas Noroccidentales. Entre éstas se reconocen dos épocas de deformación de los granitoides; de acuerdo a la clasificación de Higgins (1971 corresponden a esquistos miloníticos, gneises miloníticos y protomilonitas. Los primeros se habrían formado a temperaturas superiores a los 3500 C y a profundidades de unos 15 km, bajo un régimen cuasi plástico de deformación, mientras que las condiciones de formación de las protomilonitas corresponden a una zona de transición elástico-friccional a cuasiplástico, a temperaturas y profundidades algo menores.Además se describe también la facies granítica no deformada, que se halla en contacto neto con las anteriores y un ortogneis que representa la roca de caja en la que se instruyeron los granitoides.Los datos estructurales y observaciones de indicadores cinemáticos sugieren un plano de cizalla principal de rumbo NNW e inclinación al este, cuyo movimiento relativo es de carácter inverso, produciendo un cabalgamiento con vergencia al W. El análisis geométrico de diagramas petrof

  3. Tectonic evolution of the Sierra Maestra Mountains, SE Cuba, during Tertiary times: From arc-continent collision to transform motion

    Science.gov (United States)

    Rojas-Agramonte, Y.; Neubauer, F.; Garcia-Delgado, D. E.; Handler, R.; Friedl, G.; Delgado-Damas, R.

    2008-09-01

    A structural study was carried out along the southern Sierra Maestra mountain range, SE Cuba. This was aimed to monitor the effects of Paleogene island arc formation and collision due to convergence of the Caribbean and North American plates and subsequent Neogene disruption of the arc by initiation of the North Caribbean Transform Fault. In the Sierra Maestra two different and unrelated volcanic arcs are exposed, one of Cretaceous age (pre-Maastrichtian) and the other of Paleogene age, the latter forming the main expression of the mountain range. The volcanic arcs are overlain by Middle-Upper Eocene siliciclastic, carbonate and terrigenous rocks. Six distinct phases of deformation were recognized in this area (D1-D6). The first phase (D1) is related to the intrusion of a set of extensive subparallel, N-trending subvertical basalt-andesite dikes which record mainly E-W extension and N-S shortening during the Late Paleocene to Middle Eocene. The final stage of collision of eastern Cuba (Caribbean plate) with the Bahamas Platform (North American plate) began in the Middle Eocene and coincided with cessation of magmatism in the Sierra Maestra. Following uplift in the Sierra Maestra, coarse clastic sediments were deposited along the northern edge with clast provenance from the uplifted, southerly located, areas. Between Late Middle Eocene and Early Oligocene, rocks of the Sierra Maestra were deformed by nearly east-west trending folds and north-vergent thrust faults (D2) in an overall antiformal structure. This deformation was linked to a shift in the stress regime of the Caribbean plate from mainly N-S to NE-SW compression. Subsequent shifting in plate motion caused the abandonment of the Nipe-Guacanayabo fault system in the Early Oligocene and initiation of a deformation front to the south where the Oriente fault is now located. Shortening structures within the Sierra Maestra were overprinted in the Oligocene to Early Miocene by widespread extensional structures (D3

  4. El paisaje vegetal de la Sierra de Juan Robre y Jana (Oriente de Asturias

    Directory of Open Access Journals (Sweden)

    Ruiz Fernández, Jesús

    2006-06-01

    Full Text Available This paper is aimed at studying the vegetal formations found in a middle altitude ridge on Eastern Asturias. The characteristics and current distribution of these formations result from a combination of factors such as the climate, the relief, the soil and the systematic human action. Particularly relevant are the beech forests, the evergreen holm oak and the willow groves. Mixed forests of atlantic deciduous leaves species are properly represented, as well as chestnuts and oak groves. However, the most extended vegetal formations are heathers, gorses, ferns and pastures, as a consequence of traditional agricultural practices.

    Se estudian las formaciones vegetales existentes en una sierra de altitud media del oriente asturiano. Las características y la distribución actual de dichas formaciones son el resultado de la combinación de factores como el clima, el relieve, los suelos y la secular intervención humana. Por su elevado interés destacan formaciones como los hayedos, los encinares y las saucedas arbustivas. Los bosques mixtos de frondosas planocaducifolias también están bien representados, al igual que los castañedos y los robledales. No obstante las formaciones que más superficie ocupan son los brezales, los helechales, los aulagares y los pastizales, fruto de las prácticas desarrolladas al amparo del sistema de explotación agrario tradicional.

  5. Calibrating Late Quaternary terrestrial climate signals: radiometrically dated pollen evidence from the southern Sierra Nevada, USA

    Science.gov (United States)

    Litwin, Ronald J.; Smoot, Joseph P.; Durika, Nancy J.; Smith, George I.

    1999-01-01

    We constructed a radiometrically calibrated proxy record of Late Pleistocene and Holocene climate change exceeding 230,000 yr duration, using pollen profiles from two cores taken through age-equivalent dry lakes - one core having greater age control (via 230Th alpha mass-spectrometry) and the other having greater stratigraphic completeness. The better dated of these two serial pollen records (Searles Lake) served as a reference section for improving the effective radiometric age control in a nearby and more complete pollen record (Owens Lake) because they: (1) are situated ~90 km apart in the same drainage system (on, and immediately leeward of, the eastern flank of the Sierra Nevada), and (2) preserved strikingly similar pollen profiles and concordant sequences of sedimentological changes. Pollen assemblages from both lakes are well preserved and diverse, and document serial changes in Late Pleistocene and Holocene plant zone distribution and composition in the westernmost Great Basin; they consist of taxa now inhabiting montane forest, woodland, steppe, and desert-scrub environments. The studied core intervals are interpreted here to be the terrestrial equivalent of marine δ18O stages 1 through 9; these pollen profiles now appear to be among the best radiometrically dated Late Pleistocene records of terrestrial climate change known.

  6. Timing and new geomorphologic evidence of the last deglaciation stages in Sierra Nevada (southern Spain)

    Science.gov (United States)

    Palacios, David; Gómez-Ortiz, Antonio; Andrés, Nuria; Salvador, Ferrán; Oliva, Marc

    2016-10-01

    The main objective of this research is to improve knowledge of the deglaciation stages in Sierra Nevada (southern Spain) by applying 36Cl cosmogenic exposure dating to 28 samples from moraine and fossil rock glacier boulders and glacial polished surfaces, in 5 glaciated valleys around Veleta Peak (3396 m asl; 37°03‧02″N 3°20‧54″W). The results show that shortly before the Last Glacial Maximum (LGM) and during the LGM, the heads of the glacial valleys were occupied by ice tongues, with possible glacial transfluence between the valleys. After 19 ka, a major glacial regression started, but glaciers during the Oldest Dryas (OD) expanded again and refilled the valley bottoms. The glacial advances of the pre-LGM, LGM and OD formed polygenic moraine systems. During the Bølling-Allerød the glaciers receded and probably disappeared. Thereafter, the valley bottoms remained ice-free. During the Younger Dryas (YD) small glaciers developed again, but only in cirques shaped on east-facing slopes. Subsequently, these glaciers started retreating towards their valley heads and finally disappeared completely. With the onset of the Holocene, rock glaciers developed inside the deglaciated cirques on the eastern slopes of some valleys, but only under the most active and protected headwalls did large complex rock glaciers develop and remained active until the mid-Holocene.

  7. Tafonomía sobre asociaciones de vertebrados registradas en trampas fluviales de la Región Pampeana (Buenos Aires, Argentina

    Directory of Open Access Journals (Sweden)

    Pomi, L. H.

    2008-12-01

    Full Text Available We describe a new taphonomic mode from a fluvial system developed in channel terraces located at the Pampean Region (Quequén Grande River, Buenos Aires, Argentina associated with natural vertical cavities («marmits». We analyzed a recent (mainly aquatic vertebrate assemblage accumulated in these cavities, which operate as bone traps. Our observations suggest that these traps have accumulated isolated specimens and live or dead complete individuals during high hydric regime (torrential rains. Skeletal part representation indicates that exists a bone selection. We compare the element differential survey with different variables (structural bone density, original representation in a skeleton, size, form and volume, concluding that selection was associated with floating capabilities of missing bones (e.g. vertebrae.Se da a conocer un nuevo modo tafonómico reconocido en un sistema fluvial ubicado en la Región Pampeana (provincia de Buenos Aires, Argentina. Éste se encuentra asociado a cavidades verticales (marmitas desarrolladas en terrazas del canal principal del río Quequén Grande. Se estudió una asociación de vertebrados actuales (en su mayoría de hábitos acuáticos acumulados en estas cavidades, las cuales actuaron como trampas para los especímenes. El estudio de la muestra y observaciones realizadas in situ, sugieren que dicha trampa acumuló individuos completos (vivos o muertos y especímenes aislados durante eventos de alto régimen hídrico (lluvias torrenciales. La representación de partes anatómicas indica una selección de elementos. Se comparó la supervivencia diferencial de cada elemento con diferentes variables (densidad ósea estructural, representación original en el esqueleto, tamaño, forma y volumen, concluyendo que la selección observada se produjo por la capacidad de flotación de los elementos ausentes (p. ej., vértebras.

  8. Sequence variability and geographic distribution of Lassa virus, Sierra Leone.

    Science.gov (United States)

    Leski, Tomasz A; Stockelman, Michael G; Moses, Lina M; Park, Matthew; Stenger, David A; Ansumana, Rashid; Bausch, Daniel G; Lin, Baochuan

    2015-04-01

    Lassa virus (LASV) is endemic to parts of West Africa and causes highly fatal hemorrhagic fever. The multimammate rat (Mastomys natalensis) is the only known reservoir of LASV. Most human infections result from zoonotic transmission. The very diverse LASV genome has 4 major lineages associated with different geographic locations. We used reverse transcription PCR and resequencing microarrays to detect LASV in 41 of 214 samples from rodents captured at 8 locations in Sierra Leone. Phylogenetic analysis of partial sequences of nucleoprotein (NP), glycoprotein precursor (GPC), and polymerase (L) genes showed 5 separate clades within lineage IV of LASV in this country. The sequence diversity was higher than previously observed; mean diversity was 7.01% for nucleoprotein gene at the nucleotide level. These results may have major implications for designing diagnostic tests and therapeutic agents for LASV infections in Sierra Leone.

  9. Impact breccias in carbonate rocks, Sierra Madera, Texas.

    Science.gov (United States)

    Wilshire, H. G.; Howard, K. A.; Offield, T. W.

    1971-01-01

    Two main types of deformational breccia occur in the Sierra Madera cryptoexplosion structure: monolithologic breccias composed of shattered rock of a single lithology and mixed breccias composed of rocks of several lithologies. Monolithologic breccias generally show no mineralogic signs of shock deformation, but a few samples are shatter-coned in a manner suggesting simultaneous formation of breccias and shatter cones. Mixed breccias, forming irregular, cross-cutting bodies, consistently contain moderately to highly shocked material, with mineralogic evidence of shock pressures of 50 kb to more than 200 kb, which, with evidence from the structural geometry of Sierra Madera and orientation of shatter cones, indicate an impact origin of the breccias. The mode of occurrence of the breccias, petrographic characteristics, and association with shock features are shared by breccias in many other cryptoexplosion structures in both carbonate and crystalline rock terranes, suggesting that such breccias have a common origin.

  10. SIERRA/Aero User Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    SIERRA/Aero is a compressible fluid dynamics program intended to solve a wide variety compressible fluid flows including transonic and hypersonic problems. This document describes the commands for assembling a fluid model for analysis with this module, henceforth referred to simply as Aero for brevity. Aero is an application developed using the SIERRA Toolkit (STK). The intent of STK is to provide a set of tools for handling common tasks that programmers encounter when developing a code for numerical simulation. For example, components of STK provide field allocation and management, and parallel input/output of field and mesh data. These services also allow the development of coupled mechanics analysis software for a massively parallel computing environment. In the definitions of the commands that follow, the term Real_Max denotes the largest floating point value that can be represented on a given computer. Int_Max is the largest such integer value.

  11. SIERRA/Aero Theory Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    SIERRA/Aero is a two and three dimensional, node-centered, edge-based finite volume code that approximates the compressible Navier-Stokes equations on unstructured meshes. It is applicable to inviscid and high Reynolds number laminar and turbulent flows. Currently, two classes of turbulence models are provided: Reynolds Averaged Navier-Stokes (RANS) and hybrid methods such as Detached Eddy Simulation (DES). Large Eddy Simulation (LES) models are currently under development. The gas may be modeled either as ideal, or as a non-equilibrium, chemically reacting mixture of ideal gases. This document describes the mathematical models contained in the code, as well as certain implementation details. First, the governing equations are presented, followed by a description of the spatial discretization. Next, the time discretization is described, and finally the boundary conditions. Throughout the document, SIERRA/ Aero is referred to simply as Aero for brevity.

  12. Courtright intrusive zone: Sierra National Forest, Fresno County, California.

    Science.gov (United States)

    Bateman, P.C.; Kistler, R.W.; DeGraff, J.V.

    1984-01-01

    This is a field guide to a well-exposed area of plutonic and metamorphic rocks in the Sierra National Forest, Fresno County, California. The plutonic rocks, of which three major bodies are recognized, besides aplite and pegmatite dykes, range 103 to approx 90 m.y. in age. Points emphasized include cataclastic features within the plutonic rocks, schlieren and mafic inclusions. (M.A. 83M/0035).-A.P.

  13. Promoting Mobile Financial Transactions : A Case Study Zain Sierra Leone

    OpenAIRE

    Atuyota-Ejughemre, Kesiena

    2009-01-01

    Title – Promoting Mobile Financial Transactions: A Case study of Zain Sierra Leone Author – Kesiena Atuyota-Ejughemre Supervisor - Anders Hederstierna Department: School of Management, Blekinge Institute of Technology Course: Master’s thesis in business administration, 15 credits (ECTS). Background and Problem Discussion: There are challenges associated with overly cash based societies. The use of mobile financial systems could address some of these challenges. Understanding the factors that ...

  14. Foundering lithosphere imaged beneath the southern Sierra Nevada, California, USA.

    Science.gov (United States)

    Boyd, Oliver S; Jones, Craig H; Sheehan, Anne F

    2004-07-30

    Seismic tomography reveals garnet-rich crust and mantle lithosphere descending into the upper mantle beneath the southeastern Sierra Nevada. The descending lithosphere consists of two layers: an iron-rich eclogite above a magnesium-rich garnet peridotite. These results place descending eclogite above and east of high P wave speed material previously imaged beneath the southern Great Valley, suggesting a previously unsuspected coherence in the lithospheric removal process.

  15. Modelos de asentamiento en la sierra norte de Soria

    Directory of Open Access Journals (Sweden)

    Manuel CORRAL CAÑÓN

    2009-10-01

    Full Text Available En esta comunicación intentaremos una aproximación a las estructuras económicas y los modelos de asentamiento de los poblados de la Edad del Hierro en la Sierra norte de Soria. Nuestra intención es reconocer las diferencias entre los asentamientos del Hierro I y II, tanto en lo que refiere a las posibilidades del entorno, como a los esquemas de organización de los habitats.

  16. La susceptibilidad magnética del batolito de Achala (Devónico, Sierra Grande de Córdoba y sus diferencias con otros granitos achalianos The magnetic susceptibility of the Achala Batholith (Devonian, Sierra Grande de Córdoba and its difference with other Achalian granites

    Directory of Open Access Journals (Sweden)

    Silvana E. Geuna

    2008-09-01

    Full Text Available El magmatismo devónico de las Sierras Pampeanas de Córdoba y San Luis está representado por batolitos y plutones de composición monzogranítica y forma subelíptica, emplazados en un basamento metamórfico-plutónico eopaleozoico. Se distinguen dos grupos: el primero, compuesto por granitoides con hornblenda-biotita, metaluminosos a débilmente peraluminosos; y el segundo, formado por granitoides con biotita y muscovita, peraluminosos. Ambos grupos se caracterizan respectivamente por tener magnetita e ilmenita como fases accesorias, lo cual genera propiedades magnéticas distintivas. Entre ellos, el batolito de Achala, Córdoba, con una extensión de casi 2.500 km², es un buen exponente de los granitos paramagnéticos (no magnéticos. Su mineralogía magnética fue caracterizada en cuarenta y un sitios, la mayoría de ellos en el Monzogranito Achala. Se determinó una susceptibilidad magnética promedio muy baja, 15 x 10-5 (SI, controlada por el contenido de biotita e ilmeno- hematita. Veintiún sitios mostraron remanencia magnética estable portada por hematita, que aparece como un mineral accesorio, intercrecida con discos de exsolución de (hemoilmenita. La anisotropía de susceptibilidad magnética es débil y predominan las formas obladas, como es usual en fábricas magmáticas de granitos paramagnéticos; casi no se obtuvieron lineaciones. El grado de anisotropía es mayor en zonas con cizallamiento magmático, debido al efecto de la deformación subsolidus. El magnetismo débil del monzogranito de Achala contrasta con el carácter magnético de los plutones monzograníticos porfíricos más representativos de otros batolitos de la región, como Renca, Cerro Áspero y Las Chacras-Piedras Coloradas. La virtual ausencia de magnetita, junto con la presencia de ilmeno-hematita exsuelta, indica que un enfriamiento bajo condiciones oxidantes sería el responsable del carácter paramagnético de Achala. Como consecuencia de aplicación pr

  17. Hydrocode modeling of the Sierra Madera impact structure

    Science.gov (United States)

    Goldin, Tamara J.; Wünnemann, Kai; Melosh, H. Jay; Collins, Gareth S.

    We present the first hydrocode simulations of the formation of the Sierra Madera structure (west Texas, USA), which was caused by an impact into a thick sedimentary target sequence. We modeled Sierra Madera using the iSALE hydrocode, and here we present two best-fit models: 1) a crater with a rim (final crater) diameter of ˜12 km, in agreement with previous authors' interpretations of the original structure, and 2) a crater ˜16 km in diameter with increased postimpact erosion. Both models fit some of the geologic observational data, but discrepancies with estimates of peak shock pressure, extent of deformation, and stratigraphic displacement remain. This study suggests that Sierra Madera may be a larger crater than previously reported and illustrates some of the challenges in simulating impact deformation of sedimentary lithologies. As many terrestrial craters possess some amount of sedimentary rocks in the target sequence, numerical models of impacts into sedimentary targets are essential to our understanding of target rock deformation and the mechanics of crater formation.

  18. Attenuation Tomography of Sierra Negra Volcano of the Galapagos Archipelago

    Science.gov (United States)

    Rodd, R.; Lees, J. M.

    2014-12-01

    Following relocation of events with the double-difference location algorithm (HypoDD), we apply tomographic methods to extract 3D attenuation models illuminating the plumbing system of the Sierra Negra Caldera of the Galapagos Archipelago. The dataset consists of 1737 events recorded from July 2009 to June 2011 on the 17-station SIGNET broadband seismic array. We use t* spectral decay methods for both P- and S- phases with the clustered locations to highlight locations where significant variations in Q suggest the presence of magma melt. While the presence of a magma sill, at least 2 km depth, is indicated by InSAR and GPS studies, the delineated magma body has not been explored in detail. The lower bound of the proposed magma accumulation is still under question and thus forms the primary target of this research. Melt replenishment and degassing of the magma sill is believed to cause inflation and/or deflation of the caldera floor. Imaging the extent of the magma sill will provide insight into the feeder system and deformation process of the Sierra Negra caldera. Detailed relocation, Qp and Qs inversion, as well as estimates of the scattering attenuation using coda-normalization technique will be presented. The close relationship between seismic attenuation and the thermal state of the magmatic system suggests we can distinguish melt and/or fluid regions within the Sierra Negra plumbing system.

  19. Environmental values and risk: A review of Sierra Club policies

    Energy Technology Data Exchange (ETDEWEB)

    Craig, P.P. [Univ. of California, Davis, CA (United States). Graduate Group in Ecology

    1999-12-01

    Sierra Club values are driven by an overriding environmental ethic. Sierra Club environmental values may be characterized by the concept of 'usufruct' a term favored by United States Founding Father Thomas Jefferson. Usufruct conveys the idea that the environment is ours to use, but not to destroy. Each generation has the obligation to pass on to future generations a world at least as environmentally rich as the one it inherited. It is appropriate to accept risk today in order to preserve the environment for generations yet to come. As viewed through the lens of its formal policies, the Sierra Club is an organization that embraces technology, but insists that technology be evaluated comprehensively, taking full account of both environmental and social externalities. The Club is 'risk averse' with respect to early introduction of technologies seen as likely to have significant negative environmental or social impact. The Club places heavy emphasis on process, which must involve the public meaningfully.

  20. Interpretation of the Isabella High Wave-Speed Anomaly as the Partially Delaminated High-Density Root of the Southern Sierra Nevada Batholith, California

    Science.gov (United States)

    Saleeby, J.; Le Pourhiet, L.

    2012-12-01

    High resolution tomography of the Sierra Nevada Earthscope Project (Reeg, 2008 & Jones et al., 2012) shows that the core area of the Isabella anomaly (Vp+4-6%) resembles a prolate antiformal slab that plunges steeply SE into the upper mantle to ~200 km depth, extending down from a zone of lower crustal attachment that runs along the southwestern Sierra Nevada and adjacent eastern San Joaquin basin. Receiver function, refraction and tomography also show that areas to the east and south of lower crustal attachment consist of ascended asthenosphere lying directly beneath tectonized Moho. The lower-velocity envelope of the anomaly (Vp+1-4%) extends to 250-300 km depths and covers cross-sectional areas locally in excess of 2x of the higher Vp core. We have leveraged lithospheric structure and geologic history against thermal-mechanical modeling in pursuit of an integrated story for the physical and geologic processes that are governing the development of the anomaly. Initial structure is constrained by mantle xenoliths, differentially exhumed lower crustal exposures, and deep cores in the basin. The initial state further recognizes that: 1. the sub-Sierra Nevada batholith mantle lithosphere, including a substantial thickness (35-40 km) of eclogitic (arclogite) cumulates that were produced during high magma flux arc activity, was cooled to a conductive geotherm by flat slab subduction at the end of the Cretaceous; and 2. the gravitationally metastable mantle lithosphere was thermally mobilized from beneath in the Neogene by the opening of a slab window, which also imposed a state of modest regional extension. We have resolved a class of models that successfully predicts the structure of the anomaly, the timing and kinematics of related lithospheric separation and focused extensional tectonism, the timing and source characteristics of related volcanism, and the spatial/temporal patterns of observed subsidence and uplift transients. A general aspect of most of our model

  1. Near-roof structure and crack-seal emplacement, Colosseum pluton, Sierra Nevada, California

    Science.gov (United States)

    Bartley, J. M.; Glazner, A. F.; Coleman, D. S.

    2011-12-01

    Field evidence from diverse localities indicates that dike-like granitic plutons are emplaced by magmatic crack-seal, yielding plutons that are essentially huge composite dikes. Plutons that are equant in map view may also form by crack-seal from increments that are subhorizontal and vertically stacked, but field evidence to assess this hypothesis is scarce. Here we present evidence that the Late Cretaceous, granitic Colosseum pluton of Moore (1963), which crops out along the Sierra Nevada crest southwest of Big Pine, California, may have been emplaced as horizontal sheets by crack-seal. The equant outcrop pattern of the elliptical, 2x3 km Colosseum pluton as mapped by Moore (1963) mainly reflects Pleistocene glacial erosion that cut ~600 m down through the pluton's gently sloping roof contact. Moore mapped a steep eastern contact with the Spook pluton, but our field observations suggest that the Spook and Colosseum plutons may be the same. This would imply that the pluton is much larger and that the map pattern is not elliptical. Additionally, the exposed intrusive contact everywhere dips gently, but the eastern intrusive contact has been cut off by the Sierran frontal fault. If so, up to 2.5 km of largely unexplored vertical relief in the pluton is exposed on the eastern escarpment of the Sierra Nevada. Geologic and bulk magnetic susceptibility mapping of near-roof rocks revealed the following. (1) Although the intrusive contact sharply truncates wall-rock foliation, xenoliths are absent, even at contacts, indicating that stoping was an insignificant process. (2) The pluton contains a subhorizontal sheet of leucogranite that is broadly concordant with the roof but bounded both above and below by more typical biotite granodiorite. This sheet may represent one or more intrusive increments. (3) Along the western contact, thin tabular apophyses of the pluton intrude its subvertically layered and foliated roof. Although some of these dip steeply and are concordant

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Active basement uplift of Sierra Pie de Palo (Northwestern Argentina): Rates and inception from10Be cosmogenic nuclide concentrations

    Science.gov (United States)

    Siame, Lionel L.; Sébrier, Michel; Bellier, Olivier; Bourlès, Didier; Costa, Carlos; Ahumada, Emilio A.; Gardini, Carlos E.; Cisneros, Hector

    2015-06-01

    Quaternary tectonic and denudation rates are investigated for an actively growing basement anticline: the Sierra Pie de Palo range, which belongs to the Andean foreland of Northwestern Argentina (28°S-33°S). In this study, a detailed morphometric analysis of the topography is combined with in situ-produced cosmogenic10Be concentrations measured in (1) surface boulders abandoned on alluvial terraces affected by fault activity (along the north bounding fault) and growth of the basement fold (along the southeastern border), (2) bedrock outcrops corresponding to an exhumed and folded, regional erosion surface, and (3) fluvial sediments sampled at the outlets of several watersheds. Along the eastern and northern borders of the range, incision and uplift rates have been estimated at approximately 0.5 and 1 mm/yr when integrated on Holocene and Pleistocene time scales, in close agreement with both long-term (structural and basin evolution data) and short-term (GPS-derived velocity field) analyses. Cosmogenic-derived denudation and uplift rates combined with geomorphic characteristics of watersheds and river channels allows estimating the onset of the uplift at 4-6 Ma, followed by a more recent period of topographic rejuvenation at roughly 1-2 Ma, probably synchronous with steepening of the eastern and northern flanks of the anticline.

  4. The Eastern Partnership

    DEFF Research Database (Denmark)

    Nielsen, Kristian L.; Vilson, Maili

    2014-01-01

    When the EU launched the Eastern Partnership (EaP) in 2009, it did so with much rhetoric about projecting its soft power into Eastern Europe. Yet today, the EU's soft power project seems to have stalled, with developments in the region being less than favourable. This article argues that the EaP ...

  5. Eastern Europe's Silicon Rush

    Science.gov (United States)

    Woodard, Colin

    2007-01-01

    This article presents how the fast expansion of information technology industry in eastern Slovakia is putting a strain on its labor supply. Suddenly, computer-science graduates have become one of the former Eastern Bloc's greatest assets, attracting multinational technology companies hungry for skilled programmers, technicians, and engineers.…

  6. Ebola Virus Diagnostics: The US Centers for Disease Control and Prevention Laboratory in Sierra Leone, August 2014 to March 2015.

    Science.gov (United States)

    Flint, Mike; Goodman, Christin H; Bearden, Scott; Blau, Dianna M; Amman, Brian R; Basile, Alison J; Belser, Jessica A; Bergeron, Éric; Bowen, Michael D; Brault, Aaron C; Campbell, Shelley; Chakrabarti, Ayan K; Dodd, Kimberly A; Erickson, Bobbie R; Freeman, Molly M; Gibbons, Aridth; Guerrero, Lisa W; Klena, John D; Lash, R Ryan; Lo, Michael K; McMullan, Laura K; Momoh, Gbetuwa; Massally, James L; Goba, Augustine; Paddock, Christopher D; Priestley, Rachael A; Pyle, Meredith; Rayfield, Mark; Russell, Brandy J; Salzer, Johanna S; Sanchez, Angela J; Schuh, Amy J; Sealy, Tara K; Steinau, Martin; Stoddard, Robyn A; Taboy, Céline; Turnsek, Maryann; Wang, David; Zemtsova, Galina E; Zivcec, Marko; Spiropoulou, Christina F; Ströher, Ute; Towner, Jonathan S; Nichol, Stuart T; Bird, Brian H

    2015-10-01

    In August 2014, the Viral Special Pathogens Branch of the US Centers for Disease Control and Prevention established a field laboratory in Sierra Leone in response to the ongoing Ebola virus outbreak. Through March 2015, this laboratory tested >12 000 specimens from throughout Sierra Leone. We describe the organization and procedures of the laboratory located in Bo, Sierra Leone.

  7. Non-Governmental Organizations in Africa: The Leonenet Street Children Project in Sierra Leone

    Science.gov (United States)

    Hinton, Samuel

    2005-01-01

    The purpose of this paper is to provide snapshots of observations, interventions, and processes in the day to day working of a child charity in Sierra Leone. There were 114 local and 49 overseas funded Non Governmental Organizations (NGOs) in Sierra Leone in 2002. The Leonenet Street Children Project was founded in 1996 by the membership of the…

  8. 75 FR 44942 - 2015 Resource Pool-Sierra Nevada Customer Service Region

    Science.gov (United States)

    2010-07-30

    ... Nevada Customer Service Region AGENCY: Western Area Power Administration, DOE. ACTION: Notice of Proposed... the Sierra Nevada Customer Service Region (SNR) in the Federal Register on June 25, 1999. The... Anderson, Power Marketing Manager, Sierra Nevada Customer Service Region, Western Area Power Administration...

  9. Assessment of Anemia Knowledge, Attitudes and Behaviors among Pregnant Women in Sierra Leone

    Science.gov (United States)

    M'Cormack, Fredanna A. D.; Drolet, Judy C.

    2012-01-01

    Introduction: Iron deficiency anemia prevalence of pregnant Sierra Leone women currently is reported to be 59.7%. Anemia is considered to be a direct cause of 3-7% of maternal deaths and an indirect cause of 20-40% of maternal deaths. This study explores knowledge, attitudes, and behaviors of urban pregnant Sierra Leone women regarding anemia.…

  10. Re-imaging the Modernity of Sierra Leone and Equatorial Guinea: Africa past and Africa present

    OpenAIRE

    Codling, Rosetta

    2011-01-01

    This paper engages the concept of the imposed Modernity of Europe upon the African republics of Sierra Leone and Equatorial Guinea. Evidence of the encroachment of a ‘false’ Modernity upon Africa’s Sierra Leone and Equatorial Guinea are chronicled in the works of Donato Ndongo (Shadows of Your Black Memory) and Syl Cheney Coker (The Last Harmattan of Alusine Dunbar).

  11. Nitrogen dynamics of spring-fed wetland ecosystems of the Sierra Nevada foothills oak woodland

    Science.gov (United States)

    Randall D. Jackson; Barbara Allen-Diaz

    2002-01-01

    Spring-fed wetlands are small, highly productive, patchy ecosystems nested within the oak woodland/annual grassland matrix of the Sierra Nevada foothills. In an effort to place these wetlands in a landscape context, we described seasonal variation (1999-2000 growing season) in nitrogen cycling parameters at 6 spring-fed wetland sites of the Sierra Nevada foothill oak...

  12. El registro de la pequena edad de hielo en lagunas pampeanas The record of the Little Ice Age in the Pampean lakes

    Directory of Open Access Journals (Sweden)

    Cecilia Laprida

    2009-12-01

    Full Text Available Se conoce como Pequeña Edad de Hielo (LIA al episodio acontecido entre el siglo 16 y mediados del siglo 19, durante el cual el clima en Europa se tornó frío y ocasionalmente tormentoso. En ciertas partes de Europa, las observaciones instrumentales lo abarcan parcialmente, pero para Sudamérica no se dispone de registros instrumentales contemporáneos a dicho evento. Con el objetivo de obtener nuevas evidencias para el período comprendido por la Pequeña Edad de Hielo en la llanura pampeana, se analizaron testigos cortos de la laguna de Chascomús y de la laguna del Monte los que, de acuerdo a dataciones AMS, abarcan los últimos 500 años. Ambos testigos constan de tres secuencias granodecrecientes. El análisis del registro de la laguna de Chascomús ha permitido reconocer un período benigno desde fines del siglo 15 hasta alrededor del 1700, cuando se evidencia una retracción de la laguna que inaugura un período seco. Este episodio habría continuado por casi 150 años y se revierte alrededor de 1850, momento a partir del cual los eventos de excesos hídricos comenzaron a dominar el escenario pampeano. La base del testigo de la laguna de Monte fue datada en 1441-1494 AD. Si bien el modelo de edades para este testigo aún no ha podido ser bien establecido, los eventos de Chascomús y Monte podrían ser correlacionables y expresar tendencias seculares regionales de la humedad.The Little Ice Age (LIA is a climate episode between the 16th and middle 19th centuries, characterized in Europe by colder temperatures and occasionally stormy weather. In certain areas of Europe, long instrumental observations record the Little Ice Age partially; however, in the pampean region meteorological data only started about one hundred years ago. The objective of this contribution is to provide new evidences about the Little Ice Age in the Pampean plain based on lake cores. Short cores of Chascomús and Monte lakes were analyzed and, according to AMS data

  13. Geocronología, paleoambientes y paleosuelos holocenos en la región pampeana Holocene geochronology, paleoenvironments and paleosoils in the Pampean region

    Directory of Open Access Journals (Sweden)

    E. Fucks

    2007-09-01

    Full Text Available Las condiciones paleoambientales de la región pampeana durante el Holoceno, generaron diferentes superficies de estabilización del paisaje, permitiendo la formación de suelos tanto en ambientes de la llanura marina costera como en ambientes continentales. El análisis de diferentes perfiles geológicos en cuatro localidades y sus áreas de influencia en el NE y E de la provincia de Buenos Aires, permitieron identificar eventos pedogenéticos ubicados entre circa 4.500 años AP - 3.500 años 14C AP y circa 1.700 años 14C AP, en ambientes de la llanura marina costera y eventos pedogenéticos en planicies de inundación, ubicados cronológicamente con posterioridad a los circa 8.500- 8.000 años 14C AP, finalizando 2.000 años 14C AP. La cronología radiocarbónica permitió también: 1 ubicar cronológicamente el tope de la depositación del Miembro Guerrero de la Formación Luján dentro del Holoceno temprano (circa 8.500 años 14C AP; 2 ubicar el lapso máximo de depositación del sedimento denominado aluvio actual, desde el Holoceno tardío (circa 2.500 años 14C AP hasta los depósitos actuales donde se desarrolla un suelo muy incipiente; 3 datar eventos pedogenéticos dentro del aluvio actual en circa 1.700 años 14C AP; 4 estimar el retiro del máximo transgresivo del Holoceno y el comienzo de condiciones fluviales (circa 4.500 - 4.200 años 14C AP.The palaeoenvironmental conditions in the Pampean region during the Holocene, generated different surfaces of landscape stabilization, making possible the formation of soils in coastal marine plains and continental environments. The analyses of different geological profiles in four localities and areas of influence (NE and E of Buenos Aires province, permitted to identify pedogenetic events: 1 in coastal marine plain environments, located among circa 4500 - 3500 14C years BP and circa 1700 14C years BP; 2 in flood plains, located chronologically later to circa 8500 - 8000 14C years BP

  14. Flora útil de los cafetales en la Sierra Norte de Puebla, México Useful plants of the Sierra Norte de Puebla, Mexico

    National Research Council Canada - National Science Library

    Miguel Ángel Martínez; Virginia Evangelista; Francisco Basurto; Myrna Mendoza; Antonio Cruz-Rivas

    2007-01-01

    Los cafetales de la Sierra Norte de Puebla son agroecosistemas variados en composición y estructura, donde se pueden encontrar especies vegetales cultivadas y silvestres, nativas e introducidas, y cuya diversidad florística está...

  15. Cretaceous stratigraphy and biostratigraphy, Sierra Blanca basin, southeastern New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, S.G. (New Mexico Museum of Natural History, Albuquerque, NM (United States)); Anderson, O.R. (New Mexico Bureau of Mines Mineral Resources, Socorro, NM (United States))

    1994-03-01

    The Sierra Blanca basin of Otero and Lincoln counties, New Mexico contains a Lower (upper Albian)-Upper (Santonian) Cretaceous section of marine and nonmarine strata as much as 700 m thick which represent the upper part of a regressive cycle followed by two transgressive-regressive deposition cycles. The lower 55 m of the Cretaceous section are the same tripartite Dakota Group units recognized in Guadalupe and San Miguel counties: basal Mesa Rica Sandstone (late Albian), medial Pajarito formation (late Albian) and upper Romeroville sandstone (earliest Cenomanian). The Mesa Rica and Pajarito represent a regression and are overlain disconformably by the transgressive Romeroville sandstone. Overlying transgressive marine clastics and minor carbonates of the Mancos Shale are as much as 73 m thick and include the early Turonian Greenhorn Limestone. The overlying Tres Hermanos formation (up to 91 m thick) consists of the (ascending order) Atarque sandstone and the Carthage and Fite Ranch sandstone members. These strata represent a mid-Turonian regression in response to regional tectonism (Atarque and Carthage), followed by a transgression (Fite Ranch sandstone) that ended in the deposition of the D-Cross Tongue of the Mancos Shale and Fort Hays Member of the Niobrara Formation during the late Turonian. The subsequent regression began with the Coniacian Gallup Sandstone (55 m) followed by coal-bearing Crevasse Canyon Formation (up to 244 m thick). The Coniacian-Santonian Crevasse Canyon Formation, the youngest Cretaceous unit in the basin, is disconformably overlain by middle Eocene conglomerates and red-bed siliciclastics of the Cub Mountain formation. Dakota Group age determinations in the Sierra Blanca basin are those of well-dated sections to the north, but ammonites and inoceramid bivalves from the Sierra Blanca basin provide precise age control for Cenomanian-Santonian marine and marginal marine strata and palynology and megafossil plants for nonmarine strata.

  16. Thirty Years of Change in Subalpine Forest Cover from Landsat Image Analysis in the Sierra Nevada Mountains of California

    Science.gov (United States)

    Potter, Christopher

    2015-01-01

    Landsat imagery was analyzed to understand changes in subalpine forest stands since the mid-1980s in the Sierra-Nevada region of California. At locations where long-term plot measurements have shown that stands are becoming denser in the number of small tree stems (compared to the early 1930s), the 30-year analysis of Landsat greenness index (NDVI) indicated that no consistent increases in canopy leaf cover have occurred at these same locations since the mid-1980s. Interannual variations in stand NDVI closely followed snow accumulation amounts recorded at nearby stations. In contrast, at eastern Sierra whitebark pine stand locations where it has been observed that widespread tree mortality has occurred, decreasing NDVI trends over the past 5-10 years were consistent with rapid loss of forest canopy cover. Landsat imagery was further analyzed to understand patterns of post-wildfire vegetation recovery, focusing on high burn severity (HBS) patches within burned areas dating from the late 1940s. Analysis of landscape metrics showed that the percentage of total HBS area comprised by the largest patch of recovered woody cover was relatively small in all fires that occurred since 1995, but increased rapidly with time since fire. Patch complexity of recovered woody cover decreased notably after more than 50 years of regrowth, but was not readily associated with time for fires that occurred since the mid 1990s. The aggregation level of patches with recovery of woody cover increased steadily with time since fire. The study approach using satellite remote sensing can be expanded to assess the consequences of stand-replacing wildfires in all forests of the region.

  17. Is the Isabella anomaly a fossil slab or the foundered lithospheric root of the Sierra Nevada batholith?

    Science.gov (United States)

    Hoots, C. R.; Schmandt, B.; Clayton, R. W.; Hansen, S. M.; Dougherty, S. L.

    2015-12-01

    The Isabella Anomaly is a volume of relatively high seismic velocity upper mantle beneath the southern Great Valley in California. We deployed ~45 broadband seismometers in central California to test two main hypotheses for the origin of the Isabella Anomaly. One suggests that the Isabella Anomaly is the foundered lithospheric root of the southern Sierra Nevada batholith, which delaminated on account of eclogite-rich composition and translated westward as it began to sink into the asthenosphere. The other hypothesis suggests that the Isabella Anomaly is a fossil slab fragment attached to the Monterey microplate that lies offshore of central California and thus it is mechanically coupled to the Pacific plate. Prior seismic imaging with ~70 km station spacing cannot resolve the landward termination of Monterey microplate lithosphere beneath coastal California or where/if the Isabella Anomaly is attached to North America lithosphere beneath the Great Valley. The new temporary broadband array consists of 40 broadband seismometers with ~7 km spacing extending from the central California coast to the western Sierra Nevada batholith, plus some outliers to fill gaps in the regional network coverage. The temporary array was initially deployed in early 2014 and will continue to record until October 2015 so the complete data are not yet available. Preliminary Ps scattered wave images show an abrupt ~6 km increase in Moho depth eastward across the San Andreas fault, a strong positive impedance contrast that dips westward from ~7-25 km beneath Great Valley, and a sharp Moho with a slight westward dip beneath the western edge of the Sierra Nevada batholith. Apparently low impedance contrast characterizes the Moho beneath the eastern Great Valley and foothills, consistent with near mantle velocities in the lower crust. Processing of the cumulative data that will be available in October 2015 and incorporation of new tomography models into scattered wave imaging are needed before

  18. Agrarian change and labour migration in the Sierra of Ecuador.

    Science.gov (United States)

    Peek, P

    1980-01-01

    "Among the effects produced in the Sierra of Ecuador by the programme of land reforms launched in 1964 was a reduction in the incomes from small-scale farming. At the same time, the growth of productive employment in urban areas was insufficient to provide round-the-year work to the fast growing army of jobseekers. Analysis of the agrarian structure and migration patterns before and after 1964 suggests that it was primarily this combination of circumstances that produced a pronounced shift towards short-term rather than permanent migration, thereby providing industry and services with the labour they needed while avoiding the disadvantages of severe urban overpopulation."

  19. Modeling Patterns of Precipitation Phase in the Central Sierra Nevada

    Science.gov (United States)

    Strikas, O.; Pavelsky, T.

    2013-12-01

    Snowpack provides 75% of summer hydrologic flow in the western United States. This summer flow is vitally important in California, the country's leading producer of agriculture, with $43.5 billion dollars in cash receipts in 2011. Snowpack in the California Sierra Nevada has declined by approximately half from 1900 to 1990. In this study, we use the Weather Research and Forecasting (WRF) regional climate model at a 3km resolution to understand the critical temperature window at which both snow and rain fall for the Central Sierra Nevada during the 2002 water year. Results suggest that temperature and snow fraction [snowfall / (snowfall + rainfall)] share a logistic relationship with the snow fraction being 1 until approximately 272 K, then the snow fraction decreases by approximately 22%/K leveling at 0 snow fraction at 276.5 K. We further examine the spatial patterns of temperatures, precipitation amounts, and precipitation types in the Sierra Nevada to determine the areas of greatest potential snow to rain transition under a future warmer climate. Preliminary results suggest that the high risk areas are at the low to mid elevations. This research provides evidence that even a minor increase in temperature (+0.5 K) will yield changes in spring and summer hydrographs for the region. The spatial variability of IPCC temperature regime change for 2050 and 2100 will be downscaled for a higher resolution prediction of precipitation. It is currently under investigation how the proposed IPCC (A1 and B2) predictions of climate change for the region by 2050 (+2.7 K; +1.6 K ) and 2100 (+4.4 K; +2.7 K) will alter the corresponding annual river hydrographs. Given the complex topography of the Sierra Nevada, several spatial interpolations using GIS and statistical algorithms will be executed to render this high resolution (3km) output. Other future work with collaborators intends to model the agricultural risk associated with our predicted changes. This plot demonstrates the

  20. Sierra Leone After the War : Reconstruction, Aid and Corruption

    OpenAIRE

    Camara, Pa Musa

    2012-01-01

    Investors have stayed away from the African continent for a very long time and rightfully so. The continent is fraught with civil unrest from Somalia to Sudan, from Libya to Democratic Republic of Congo. Most of the countries that are experiencing civil unrests are resource-rich nations. This gives credence to the concept of ‘resource curse’ for resource-rich nations. Sierra Leone is no exception, having suffered an eleven-year long civil war, from 1991 to 2002, causing major setbacks for the...

  1. Dos nuevas inscripciones latinas de Elche de la Sierra (Albacete

    Directory of Open Access Journals (Sweden)

    Julián Francisco MARTÍN RUIZ

    2009-12-01

    Full Text Available Apareció la lápida al sitio llamado «El Mojón», en el término municipal de Elche de la Sierra, a unos dos kilómetros del núcleo principal de población y bastante más cerca —seiscientos metros aproximadamente— de una aldea dependiente de éste, conocida en la actualidad con el nombre de Villares y en la antigüedad con el de Gutar.

  2. Morfometría dental aplicada al análisis de los procesos de diferenciación poblacional en el sudeste de la Región Pampeana y norte de Patagonia durante el Holoceno Tardío

    Directory of Open Access Journals (Sweden)

    Bernal, Valeria

    2005-01-01

    Full Text Available El objetivo del presente trabajo es analizar la variabilidad en la morfometría dental en muestras de restos óseos humanos del SE de la Región Pampeana asignables a distintos momentos del Holoceno tardío y comparar, desde un punto de vista espacial, el grado de similitud morfológica con muestras procedentes del NE de Patagonia (valles de Río Negro y Chubut, San Blas, Isla Gama. Se relevaron los diámetros mesiodistal y bucolingual medidos a nivel del margen cervical en la totalidad de las piezas dentales permanentes correspondientes a 130 individuos de ambos sexos. Las medidas obtenidas fueron empleadas en análisis estadísticos multivariados con el fin de evaluar el grado similitud morfológica entre las muestras. Los resultados obtenidos indican que: 1- hay diferencias entre las muestras procedentes del SE de la Región Pampeana correspondientes al Holoceno tardío inicial y final, caracterizándose estas últimas por un mayor tamaño dental; 2- la muestra del SE de la Región Pampeana correspondiente al Holoceno tardío final presenta mayor similitud morfológica con la muestra más tardía del valle de Río Negro; 3- existen variaciones cronológicas en el tamaño dental entre las muestras procedentes del NE de Patagonia.

  3. PROBLEMS IN THE ADMISSION TO HIGHER EDUCATION IN THE LOWER SIERRA DE SONORA, CASE: UNIVERSITY OF SIERRA

    Directory of Open Access Journals (Sweden)

    Rubén Ángel Vásquez-Navarro

    2011-05-01

    Full Text Available The aim of this paper is to clarify the issues and find solutions to align somewhat academic models of institutions of higher average level and above found in the central highlands of the state of Sonora, as are the University of Sierra, and the CBTA 53 and confront the culture of the people of the importance of young people studying a degree in that region.The above educational institutions are located in the geographical catchment area and education, in fact, in the same population, in the northeastern state of Sonora. The mountains of Sonora had always intended to have a school of higher education. To justify the town of Montezuma as a geographically strategic point, and thanks to the efforts made by the governor in turn was as the University of Sierra opens its doors to students on the mountain in August 2002.For the analysis of the functioning of an educational institution in the rural sector, should take into account a wide range of factors, however, this work will be key to analyze the dislocation and inconsistency of educational models from an institution of higher average level in relationship to another level, which serve as a unique educational opportunities for the people of Sonora and surrounding Montezuma. In addition, the cultural aspect, which reflects a regional behavior of the inhabitants of the region. La Sierra University is located in the mountainous region of the state of Sonora, in the town of Montezuma, with a catchment area of more than 30 municipalities in this area, which lacked a college until recently time.

  4. Geochemistry of late Quaternary tephra-sediment sequence from north-eastern Basin of Mexico (Mexico): implications to tephrochronology, chemical weathering and provenance

    OpenAIRE

    Priyadarsi D. Roy; José Luis Arce; Rufino Lozano; M.P. Jonathan; Elena Centeno; Socorro Lozano

    2012-01-01

    A ca.30 m thick tephra-sediment sequence from the north-eastern Basin of Mexico (Pachuca subbasin, central Mexico) is investigated for stratigraphy and multi-element geochemistry to understand the tephrochronology, provenance and conditions of chemical weathering during Late Quaternary. Chemical compositions of tephra layers are compared with products from surrounding volcanic structures (Apan- Tezontepece, Acoculco, Huichapan, Sierra de las Cruces and Tláloc) in order to identify their sourc...

  5. El plutón de Serrezuela: Evento magmático del Carbonífero en el sector norte de la sierra de Pocho, Córdoba, República Argentina

    Directory of Open Access Journals (Sweden)

    GM Gómez

    2003-09-01

    . El plutón de Serrezuela de edad carbonífera (321+7,4 Ma y 303+2MA, K/Ar, representa uno de los pulsos magmáticos graníticos mas jóvenes en este sector de las Sierras Pampeanas Orientales. Este cuerpo posiblemente registre el final del ciclo magmático generador de los vecinos batolito de Achala y plutón de La Playa bajo un régimen colisional.

  6. On the relative contributions of wind vs. animals to seed dispersal of four Sierra Nevada pines.

    Science.gov (United States)

    Vander Wall, Stephen B

    2008-07-01

    Selective pressures that influence the form of seed dispersal syndromes are poorly understood. Morphology of plant propagules is often used to infer the means of dispersal, but morphology can be misleading. Several species of pines, for example, have winged seeds adapted for wind dispersal but owe much of their establishment to scatter-hoarding animals. Here the relative importance of wind vs. animal dispersal is assessed for four species of pines of the eastern Sierra Nevada that have winged seeds but differed in seed size: lodgepole pine (Pinus contorta murrayana, 8 mg); ponderosa pine (Pinus ponderosa ponderosa, 56 mg); Jeffrey pine (Pinus jeffreyi, 160 mg); and sugar pine (Pinus lambertiana, 231 mg). Pre-dispersal seed mortality eliminated much of the ponderosa pine seed crop (66%), but had much less effect on Jeffrey pine (32% of seeds destroyed), lodgepole pine (29%), and sugar pine (7%). When cones opened most filled seeds were dispersed by wind. Animals removed > 99% of wind-dispersed Jeffrey and sugar pine seeds from the ground within 60 days, but animals gathered only 93% of lodgepole pine seeds and 38% of ponderosa pine seeds during the same period. Animals gathered and scatter hoarded radioactively labeled ponderosa, Jeffrey, and sugar pine seeds, making a total of 2103 caches over three years of study. Only three lodgepole pine caches were found. Caches typically contained 1-4 seeds buried 5-20 mm deep, depths suitable for seedling emergence. Although Jeffrey and sugar pine seeds are initially wind dispersed, nearly all seedlings arise from animal caches. Lodgepole pine is almost exclusively wind dispersed, with animals acting as seed predators. Animals treated ponderosa pine in an intermediate fashion. Two-phased dispersal of large, winged pine seeds appears adaptive; initial wind dispersal helps to minimize pre-dispersal seed mortality whereas scatter hoarding by animals places seeds in sites with a higher probability of seedling establishment.

  7. Juan Carandell Pericay (1893-1937 y Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Antonio López Ontiveros

    2000-01-01

    Full Text Available Juan Carandell Pericay (1893-1937, geólogo y geógrafo ligado a la Institución Libre de Enseñanza, escribió unos trescientos títulos, con una actividad científica e intelectual muy polifacética: geología, geografía física, humana y regional, libros de viaje y excursiones pedagógicas, semiología gráfica, divulgación científica y otras actividades intelectuales y artísticas. Una parte significativa de dichas obras estuvo dedicada a las Béticas, en general, y a Sierra Nevada en particular. Aspectos considerados por Carandell sobre Sierra Nevada son los relativos a su geología, geomorfología y tectónica, la erosión y sus causas físicas y humanas, la geografía humana –con especial importancia para el tema del hábitat– y otra variada gama de temas entre los que merece mención la faceta de las representaciones del paisaje, en todas las cuales demostró no sólo sus sólidos conocimientos geológicos y geográficos, sino incluso una calidad artística más que apreciable.

  8. Eastern Equine Encephalitis

    Science.gov (United States)

    ... bite of an infected mosquito. Eastern equine encephalitis (EEE) is a rare illness in humans, and only ... EEEV have no apparent illness. Severe cases of EEE (involving encephalitis, an inflammation of the brain) begin ...

  9. Summary of the geology of the northern part of the Sierra Cuchillo, Socorroand Sierra Counties, southwestern New Mexico

    Science.gov (United States)

    Maldonado, Florian; Edited by Lucas, Spencer G.; McLemore, Virginia T.; Lueth, Virgil W.; Spielmann, Justin A.; Krainer, Karl

    2012-01-01

    The northern part of the Sierra Cuchillo is located within the northeastern part of the Mogollon-Datil volcanic field west of the Rio Grande rift in the Basin and Range Province, approximately 50 km northwest of Truth or Consequences in south-central New Mexico. The Sierra Cuchillo is a north-south, elongated horst block composed of Tertiary volcanic and intrusive rocks, sparse outcrops of Lower Permian and Upper Cretaceous rocks, and sediments of the Tertiary-Quaternary Santa Fe Group. The horst is composed mainly of a basal volcanic rock sequence of andesite-latite lava flows and mud-flow breccias with a 40Ar/39Ar isotopic age of about 38 Ma. The sequence is locally intruded by numerous dikes and plugs that range in composition from basaltic andesite through rhyolite and granite. The andesite-latite sequence is overlain by ash-flow tuffs and a complex of rhyolitic lava flows and domes. Some of these units are locally derived and some are outflow sheets derived from calderas in the San Mateo Mountains, northeast of the study area. These locally derived units and outflow sheets range in age from 28 to 24 Ma.

  10. Maintenance Support of a Field Station in Sierra Leone, West Africa

    Science.gov (United States)

    1994-03-04

    AD-A279 136 ARMY PROJECT ORDER NO: 91PP1801 TITLE: MAINTENANCE SUPPORT OF A FIELD STATION IN SIERRA LEONE , WEST AFRICA PRINCIPAL INVESTIGATOR: Brian...SUBTITLE S. FUNDING NUMBERS Maintenance Support of a Field Station in Army Project Order Sierra Leone , West Africa 91PP1801 6. AUTHOR(S) Brian W.J. Mahy...Detrick Frederick, Maryland 21702-5012 11. SUPPLEMENTARY NOTES Subtitle: Maintenance Support of a FiLd Station in Sierra Leone , West Africa for Lassa

  11. Culex Verutus, a New Species of the Subgenus Culex (Diptera: Culicidae) from Sierra Leone

    Science.gov (United States)

    1986-01-01

    216 Cu7ex verutus, a new species of the subgenu s1 Cu7ex (Diptera: Culicidae) from Sierra Leone Ralph E. Harbach’ Walter Reed Biosystematics...sp. from Sierra Leone are described and illus- trated. The new species is compared to other members of the guiarti group. This paper describes a...new species of Cu7ex collected in Sierra Leone by Dr. Yiau-Min Huang and Mr. James Pecor during field studies conducted in 1984. The species has been

  12. Crustal deformation in the south-central Andes backarc terranes as viewed from regional broad-band seismic waveform modelling

    Science.gov (United States)

    Alvarado, Patricia; Beck, Susan; Zandt, George; Araujo, Mario; Triep, Enrique

    2005-11-01

    The convergence between the Nazca and South America tectonic plates generates a seismically active backarc region near 31°S. Earthquake locations define the subhorizontal subducted oceanic Nazca plate at depths of 90-120 km. Another seismic region is located within the continental upper plate with events at depths Sierras Pampeanas and is responsible for the large earthquakes that have caused major human and economic losses in Argentina. South of 33°S, the intense shallow continental seismicity is more restricted to the main cordillera over a region where the subducted Nazca plate starts to incline more steeply, and there is an active volcanic arc. We operated a portable broad-band seismic network as part of the Chile-Argentina Geophysical Experiment (CHARGE) from 2000 December to 2002 May. We have studied crustal earthquakes that occurred in the back arc and under the main cordillera in the south-central Andes (29°S-36°S) recorded by the CHARGE network. We obtained the focal mechanisms and source depths for 27 (3.5 Sierras Pampeanas, over the flat-slab segment is dominated by reverse and thrust fault-plane solutions located at an average source depth of 20 km. One moderate-sized earthquake (event 02-117) is very likely related to the northern part of the Precordillera and the Sierras Pampeanas terrane boundary. Another event located near Mendoza at a greater depth (~26 km) (event 02-005) could also be associated with the same ancient suture. We found strike-slip focal mechanisms in the eastern Sierras Pampeanas and under the main cordillera with shallower focal depths of ~5-7 km. Overall, the western part of the entire region is more seismically active than the eastern part. We postulate that this is related to the presence of different pre-Andean geological terranes. We also find evidence for different average crustal models for those terranes. Better-fitting synthetic seismograms result using a higher P-wave velocity, a smaller average S-wave velocity and a

  13. [The indigenous population of Sierra Norte de Puebla].

    Science.gov (United States)

    Marquez Gonzalez, G

    1991-06-01

    The northern sierra region of Pueblo, Mexico, contains 1496 communities in 65 municipios and covers 1/4 of the area of the state of Puebla. The topography is steep and mountainous, and the area is inaccessible. The region contains the 3 principal zones of Mesoamerica, hot lands from sea level to 700 meters above sea level, temperate zones from 700-1500 meters, and cold country from 1500-2000 meters above sea level. Most of the population resides in the temperate and cold lands, but the hot zones are economically important. Little is known of the prehistory of the area. The Totonac were believed to have been the earliest settlers. In the mid-15th century numerous Nahua groups came to the area. In the late 15th century the region fell to the Aztecs, but their dominion was cut short by the arrival of the Spanish. Spanish penetration was relatively slow because of the difficult terrain and the lack of precious metals desired by the Spanish. The introduction of coffee cultivation in the late 19th century accelerated the adoption of urban-mestizo sociocultural and commercial elements by the indigenous population. The population of the northern sierra increased from 752,656 in 1980 to 965,976 in 1990. The 1980 census reported that 259,140 persons spoke indigenous languages, including 179,677 who spoke Nahuatl, 66,020 Totonaco, and 4921 Otomi. The most important cities are located on paved roads: Teziutland, Zacatlan, Hauachinango, and Zacapoaxtla. The municipios with predominantly monolingual indigenous populations are concentrated in the most difficult to reach areas of the central sierra massif. The region is characterized by temporary and permanent emigration of the indigenous population. The main reasons for emigration are lack of land and of alternative sources of employment, and desire for education. During the months August-December, known as the time of hunger, there is seasonal migration of household heads in search of work as laborers in cane cutting, tobacco

  14. Botanical novelties from Sierra de Maigualida, southern Venezuela. II

    Directory of Open Access Journals (Sweden)

    Grande, José R.

    2012-06-01

    Full Text Available Four new species, Siphocampylus acanthidiotrichus J.R. Grande (Campanulaceae, Phyllanthus huberi Riina & P.E. Berry (Phyllanthaceae, Sohnreyia maigualidensis J.R. Grande & Kallunki (Rutaceae, and Turnera maigualidensis J.R. Grande & Arbo (Turneraceae are described and illustrated from the summit areas of Sierra de Maigualida in the Gua - yana Highlands of southern Venezuela. To date, one genus, 32 spe cies, one subspecies, and one variety of angiosperms are known only from the Maigualida meadows and shrublands, between 1800 m and the highest elevation areas at 2400 m. Here we describe the first iteroparous species for the genus Sohnreyia K. Krause, a Turnera L. species with apically villose, apiculate petals, and a Siphocampylus Pohl species with aculeiform hairs and pinnatisect leaves. The new species, Siphocampylus acanthidiotrichus, together with S. Tillettii Steyerm., represents a morphologically distinct subgroup within the genus.

    Se describen e ilustran cuatro especies nuevas procedentes de las cumbres de la Sierra de Maigualida: Siphocampylus acanthidiotrichus J.R. Grande (Campanulaceae, Phyllanthus huberi Riina & P.E. Berry (Phyllanthaceae, Sohnreyia maigualidensis J.R. Grande & Kallunki (Rutaceae y Turnera maigualidensis J.R. Grande & Arbo (Turneraceae. Hasta ahora un género, 32 especies, una subespecie y una variedad de angiospermas se conocen exclusivamente de la Sierra de Maigualida, y todas ellas proceden de herbazales y arbustales desarrollados entre los 1800 m y las áreas más altas, a 2400 m. Aquí, se describen por primera vez una especie iterópara del género Sohnreyia K. Krause (Rutaceae, una especie de Turnera L. con pétalos apiculados apicalmente vilosos y una especie de Siphocampylus Pohl con pelos aculeiformes y hojas pinnatisectas. La nueva especie Siphocampylus acanthidiotrichus representa

  15. DNA sequences of troglobitic nicoletiid insects support Sierra de El Abra and the Sierra de Guatemala as a single biogeographical area: Implications for Astyanax

    Directory of Open Access Journals (Sweden)

    Luis Espinasa

    2014-03-01

    Full Text Available The blind Mexican tetra fish, Astyanax mexicanus, has become the most influential model for research of cave adapted organisms. Many authors assume that the Sierra de Guatemala populations and the Sierra de El Abra populations are derived from two independent colonizations. This assumption arises in part from biogeography. The 100 m high, 100 m wide Servilleta Canyon of the Boquillas River separates both mountain ranges and is an apparent barrier for troglobite dispersion. Anelpistina quinterensis (Nicoletiidae, Zygentoma, Insecta is one of the most troglomorphic nicoletiid silverfish insects ever described. 16S rRNA sequences support that this species migrated underground to reach both mountain ranges within less than 12,000 years. Furthermore, literature shows a plethora of aquatic and terrestrial cave restricted species that inhabit both mountain ranges. Thus, the Servilleta canyon has not been an effective biological barrier that prevented underground migration of troglobites between the Sierra de Guatemala and the Sierra de El Abra. The Boquillas River has changed its course throughout time. Caves that in the past connected the two Sierras were only recently geologically truncated by the erosion of the new river course. It is likely that, with the geological changes of the area and throughout the 2-8 million years of evolutionary history of cave Astyanax, there have been opportunities to migrate across the Servilleta canyon.

  16. The geology and tectonic significance of the Big Creek Gneiss, Sierra Madre, southeastern Wyoming

    Science.gov (United States)

    Jones, Daniel S.

    The Big Creek Gneiss, southern Sierra Madre, southeastern Wyoming, is a heterogeneous suite of upper-amphibolite-facies metamorphic rocks intruded by post-metamorphic pegmatitic granite. The metamorphic rocks consist of three individual protolith suites: (1) pre- to syn-1780-Ma supracrustal rocks including clastic metasedimentary rocks, calc-silicate paragneiss, and metavolcanic rocks; (2) a bimodal intrusive suite composed of metagabbro and granodiorite-tonalite gneiss; and (3) a younger bimodal suite composed of garnet-bearing metagabbronorite and coarse-grained granitic gneiss. Zircons U-Pb ages from the Big Creek Gneiss demonstrate that: (1) the average age of detrital zircons in the supracrustal rocks is ~1805 Ma, requiring a significant source of 1805-Ma (or older) detritus during deposition, possibly representing an older phase of arc magmatism; (2) the older bimodal igneous suite crystallized at ~1780 Ma, correlative with arc-derived rocks of the Green Mountain Formation; (3) the younger bimodal igneous suite crystallized at ~1763 Ma, coeval with the extensional(?) Horse Creek anorthosite complex in the Laramie Mountains and Sierra Madre Granite batholith in the southwestern Sierra Madre; (4) Big Creek Gneiss rocks were tectonically buried, metamorphosed, and partially melted at ~1750 Ma, coeval with the accretion of the Green Mountain arc to the Wyoming province along the Cheyenne belt; (5) the posttectonic granite and pegmatite bodies throughout the Big Creek Gneiss crystallized at ~1630 Ma and are correlative with the 'white quartz monzonite' of the south-central Sierra Madre. Geochemical analysis of the ~1780-Ma bimodal plutonic suite demonstrates a clear arc-affinity for the mafic rocks, consistent with a subduction environment origin. The granodioritic rocks of this suite were not derived by fractional crystallization from coeval mafic magmas, but are instead interpreted as melts of lower-crustal mafic material. This combination of mantle

  17. Shallow crustal structure of eastern-central Trans-Mexican Volcanic Belt.

    Science.gov (United States)

    Campos-Enriquez, J. O.; Ramón, V. M.; Lermo-Samaniego, J.

    2015-12-01

    Central-eastern Trans-Mexican Volcanic Belt (TMVB) is featured by large basins (i.e., Toluca, Mexico, Puebla-Tlaxcala, Libres-Oriental). It has been supposed that major crustal faults limit these basins. Sierra de Las Cruces range separates the Toluca and Mexico basins. The Sierra Nevada range separates Mexico basin from the Puebla-Tlaxcala basin. Based in gravity and seismic data we inferred the Toluca basin is constituted by the Ixtlahuaca sub-basin, to the north, and the Toluca sub-basin to the south, which are separated by a relative structural high. The Toluca depression is more symmetric and bounded by sub-vertical faults. In particular its eastern master fault controlled the emplacement of Sierra de Las Cruces range. Easternmost Acambay graben constitutes the northern and deepest part of the Ixtlahuaca depression. The Toluca-Ixtlahuaca basin is inside the Taxco-San Miguel de Allende fault system, and limited to the west by the Guerrero terrane which continues beneath the TMVB up to the Acambay graben. Mexico basin basement occupies an intermediate position and featured by a relative structural high to the north-east, as established by previous studies. This relative structural high is limited to the west by the north-south Mixhuca trough, while to the south it is bounded by the east-west Copilco-Xochimilco-Chalco sub-basin. The Puebla-Tlaxcala basin basement is the shallowest of these 3 tectonic depressions. In general, features (i.e., depth) and relationship between these basins, from west to east, are controlled by the regional behavior of the Sierra Madre Oriental fold and thrust belt basement (i.e., Oaxaca Complex?). This study indicates that an active east-west regional fault system limits to the south the TMVB (from the Nevado de Toluca volcano through the Popocatepetl volcano and eastward along southern Puebla-Tlaxcala basin). The Tenango and La Pera fault systems constituting the western part of this regional fault system coincide with northern

  18. Element Verification and Comparison in Sierra/Solid Mechanics Problems

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, Yuki; Roth, William

    2016-05-01

    The goal of this project was to study the effects of element selection on the Sierra/SM solutions to five common solid mechanics problems. A total of nine element formulations were used for each problem. The models were run multiple times with varying spatial and temporal discretization in order to ensure convergence. The first four problems have been compared to analytical solutions, and all numerical results were found to be sufficiently accurate. The penetration problem was found to have a high mesh dependence in terms of element type, mesh discretization, and meshing scheme. Also, the time to solution is shown for each problem in order to facilitate element selection when computer resources are limited.

  19. Geologic studies in the Sierra de Pena Blanca, Chihuahua, Mexico

    Science.gov (United States)

    Reyes-Cortes, Ignacio Alfonso

    The Sierra del Cuervo has been endowed with uranium mineralization, which has attracted many geological studies, and recently the author was part of a team with the goal of selecting a site of a radioactive waste repository. The first part of the work adds to the regional framework of stratigraphy and tectonics of the area. It includes the idea of a pull apart basin development, which justifies the local great thickness of the Cuervo Formation. It includes the regional structural frame work and the composite stratigraphic column of the Chihuahua Trough and the equivalent Cretaceous Mexican Sea. The general geologic features of the NE part of the Sierra del Cuervo are described, which include the folded ignimbrites and limestones in that area; the irregular large thicknesses of the Cuervo Formation; and the western vergence of the main folding within the area. Sanidine phenocrystals gave ages of 54.2 Ma and 51.8 Ma ± 2.3 Ma. This is the first time these dates have been reported in print. This age indicates a time before the folded structures which outcrop in the area, and 44 Ma is a date after the Cuervo Formation was folded. The Hidalgoan orogeny cycle affected the rocks between this lapse of time. Since then the area has been partially affected by three tensional overlapped stages, which resulted in the actual Basin and Range physiography. The jarosite related to the tectonic activity mineralization has been dated by the Ar-Ar method and yields an age of 9.8 Ma. This is the first report of a date of mineralization timing at Pena Blanca Uranium District in the Sierra del Cuervo. These are some of the frame work features that justify the allocation of a radioactive waste repository in the Sierra del Cuervo. An alluvial fan system within the Boquilla Colorada microbasin was selected as the best target for more detailed site assessment. The study also included the measurement of the alluvium thicknesses by geoelectric soundings; studies of petrography and weathered

  20. Ebola Virus Disease in Children, Sierra Leone, 2014–2015

    Science.gov (United States)

    Naveed, Asad; Wing, Kevin; Gbessay, Musa; Ross, J.C.G.; Checchi, Francesco; Youkee, Daniel; Jalloh, Mohammed Boie; Baion, David; Mustapha, Ayeshatu; Jah, Hawanatu; Lako, Sandra; Oza, Shefali; Boufkhed, Sabah; Feury, Reynold; Bielicki, Julia A.; Gibb, Diana M.; Klein, Nigel; Sahr, Foday; Yeung, Shunmay

    2016-01-01

    Little is known about potentially modifiable factors in Ebola virus disease in children. We undertook a retrospective cohort study of children Ebola holding units in the Western Area, Sierra Leone, during 2014–2015 to identify factors affecting outcome. Primary outcome was death or discharge after transfer to Ebola treatment centers. All 309 Ebola virus–positive children 2 days–12 years old were included; outcomes were available for 282 (91%). Case-fatality was 57%, and 55% of deaths occurred in Ebola holding units. Blood test results showed hypoglycemia and hepatic/renal dysfunction. Death occurred swiftly (median 3 days after admission) and was associated with younger age and diarrhea. Despite triangulation of information from multiple sources, data availability was limited, and we identified no modifiable factors substantially affecting death. In future Ebola virus disease epidemics, robust, rapid data collection is vital to determine effectiveness of interventions for children. PMID:27649367

  1. Calibration of a modified Sierra Model 235 slotted cascade impactor

    Energy Technology Data Exchange (ETDEWEB)

    Knuth, R.H.

    1979-07-01

    For measurements of ore dust in uranium concentrating mills, a Sierra Model 235 slotted cascade impactor was calibrated at a flow rate of .21 m/sup 3//min, using solid monodisperse particles and an impaction surface of Whatman No. 41 filter paper soaked in mineral oil. The reduction from the impactor's design flow rate of 1.13 m/sup 3//min (40 cfm) to 0.21 m/sup 3//min (7.5 cfm) increased the stage cut-off diameters by an average factor of 2.3, a necessary adjustment because of the anticipated large particle sizes of ore dust. The underestimation of mass median diameters, often caused by the rebound and reentrainment of solid particles from dry impaction surfaces, was virtually eliminated by using the oiled Whatman No. 41 impaction surface. Observations of satisfactory performance in the laboratory were verified by tests of the impactor in ore mills.

  2. Indigenousness without ethnicity in the Sierra Norte of Oaxaca

    Directory of Open Access Journals (Sweden)

    ROSA GUADALUPE MENDOZA ZUANY

    2014-08-01

    Full Text Available This article analyses the relationship between ethnic, indigenous and community-based identities in the communities of Ixtlan and Guelatao in the Sierra Norte of Oaxaca, Mexico. Local identities and sense of belonging to the communities prevail over ethnic identification amongst the inhabitants of these communities. The strengthening of local (community-based identity has been achieved through an internal social organisation and categorisation of the inhabitants based on their origin as a mechanism of integration, particularly in diverse communities with large numbers of outsiders. Parallel to this, new ways of defining indigenousness, without ethnic claims, are emerging through making reference to the practice of comunaliddadand attachment to localities/communities.

  3. Enteric fever in a British soldier from Sierra Leone.

    Science.gov (United States)

    Osborne, Lucy G; Brown, M; Bailey, M S

    2016-06-01

    Enteric fever (typhoid and paratyphoid) remains a threat to British troops overseas and causes significant morbidity and mortality. We report the case of a soldier who developed typhoid despite appropriate vaccination and field hygiene measures, which began 23 days after returning from a deployment in Sierra Leone. The incubation period was longer than average, symptoms started 2 days after stopping doxycycline for malaria chemoprophylaxis and initial blood cultures were negative. The Salmonella enterica serovar Typhi eventually isolated was resistant to amoxicillin, co-amoxiclav, co-trimoxazole and nalidixic acid and had reduced susceptibility to ciprofloxacin. He was successfully treated with ceftriaxone followed by azithromycin, but 1 month later he remained fatigued and unable to work. The clinical and laboratory features of enteric fever are non-specific and the diagnosis should be considered in troops returning from an endemic area with a febrile illness. Multiple blood cultures and referral to a specialist unit may be required.

  4. Enfermedad y pobreza en la Sierra de Chiapas

    Directory of Open Access Journals (Sweden)

    Eugenia Bayona Escat

    2011-07-01

    Full Text Available Este artículo indaga en la desigualdad y exclusión social que padece la población de la región Sierra, Chiapas, en el ámbito de la salud, desde los testimonios de mujeres rurales que ofrecen su visión de la salud, la enfermedad y la atención sanitaria, y desarrollan estrategias para afrontar las dificultades. Se pretende demostrar cómo en un medio adverso, caracterizado por la pobreza y olvido institucional, los trastornos físicos son reiterativos, se convierten en incurables y contribuyen a la reproducción de la marginalidad. Así, se genera la enfermedad de la pobreza, que somatiza males físicos para expresar las carencias sociales.

  5. Analysis of obsidian sources in the southern Sierra Madre occidental

    Energy Technology Data Exchange (ETDEWEB)

    Darling, J.A.; Hayashida, F.M.

    1994-12-31

    From 1991 to 1993, field surveys and geologic sampling were conducted in the region of the southern Sierra Madre Occidental in the states of Durango, Zacatecas, and Jalisco, Mexico, to investigate three previously unreported sources of obsidian or volcanic glass. The source areas are Huitzila-La Lobera, Llano Grande, and Nochistlan. Obsidian`s importance as a raw material in premodern societies for the production of tools and articles of adornment is well documented, particularly for Mesoamerica. Investigation of northern mesoamerican obsidian offers new data on these little known sources located to the north of the more thoroughly studied sources of the Mexican Neovolcanic chain. Neutron activation analysis was used to characterize the materials.

  6. Manejo forestal y diversidad genetica de Pinus patula Schiede ex Schltdl, & Cham, en Sierra Juarez, Oaxaca

    National Research Council Canada - National Science Library

    Alfonso-Corrado, Cecilia; Campos-Contreras, Jorge; Sanchez-Garcia, Gerardo; Monsalvo-Reyes, Alejandro; Clark-Tapia, Ricardo

    2014-01-01

    .... & Cham, la especie mas importante en el ramo forestal en Sierra Juarez, Oaxaca, con la finalidad de evaluar el efecto del manejo forestal en la diversidad genetica en sitios reforestados y de regeneracion natural...

  7. 76 FR 44535 - Revisions to the California State Implementation Plan, Northern Sierra Air Quality Management...

    Science.gov (United States)

    2011-07-26

    ... Management District, Sacramento Metropolitan Air Quality Management District, and South Coast Air Quality... proposing to approve revisions to the Northern Sierra Air Quality Management District (NSAQMD), Sacramento Metropolitan Air Quality Management District (SMAQMD), and South Coast Air Quality Management District......

  8. X-Ray Diffraction Powder Patterns and Thin Section Observations from the Sierra Madera Impact Structure

    Science.gov (United States)

    Huson, S. A.; Foit, F. F.; Watkinson, A. J.; Pope, M. C.

    2006-03-01

    X-Ray powder diffraction analysis and thin section observations of carbonate and siliciclastic samples from the Sierra Madera impact structure indicate moderate shock pressures (8 to 30 GPa) were generated during the formation of this crater.

  9. Critical Habitat for the Sierra Nevada Bighorn Sheep (Ovis canadensis californiana)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify the areas designated as critical habitat for the Sierra Nevada Bighorn Sheep. Critical habitat for the species occurs in twelve units: Mount...

  10. SIERRA Low Mach Module: Fuego User Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    The SIERRA Low Mach Module: Fuego along with the SIERRA Participating Media Radiation Module: Syrinx, henceforth referred to as Fuego and Syrinx, respectively, are the key elements of the ASCI fire environment simulation project. The fire environment simulation project is directed at characterizing both open large-scale pool fires and building enclosure fires. Fuego represents the turbulent, buoyantly-driven incompressible flow, heat transfer, mass transfer, combustion, soot, and absorption coefficient model portion of the simulation software. Syrinx represents the participating-media thermal radiation mechanics. This project is an integral part of the SIERRA multi-mechanics software development project. Fuego depends heavily upon the core architecture developments provided by SIERRA for massively parallel computing, solution adaptivity, and mechanics coupling on unstructured grids.

  11. Pisos de vegetacion de la sierra de catorce y territorios circundantes

    National Research Council Canada - National Science Library

    Gimenez de Azcarate, Joaquin; Gonzalez Costilla, Onesimo

    2011-01-01

    Se realizo una caracterizacion de los pisos de vegetacion reconocidos a lo largo del gradiente actitudinal en la Sierra de Catorce y zonas aledanas, en la porcion meridional del Desierto Chihuahuense...

  12. Morphologic characterization of Peromyscus schmidlyi (Rodentia: Cricetidae), an endemic of the Sierra Madre Occidental, Mexico

    National Research Council Canada - National Science Library

    Celia López-González; Diego F. García-Mendoza; Miguel M. Correa-Ramírez

    2013-01-01

    .... We compared and contrasted P. schmidlyi with P. boylii rowleyi and P. spicilegus, morphologically similar and partially sympatric species, and reevaluated the distribution of the 3 species in the Sierra Madre Occidental (SMO) of Mexico. P...

  13. Critical Habitat for the Sierra Nevada Bighorn Sheep (Ovis canadensis californiana)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — These data identify the areas designated as critical habitat for the Sierra Nevada Bighorn Sheep. Critical habitat for the species occurs in twelve units: Mount...

  14. Notes from The Field: Ebola Virus Disease Cluster - Northern Sierra Leone, January 2016.

    Science.gov (United States)

    Alpren, Charles; Sloan, Michelle; Boegler, Karen A; Martin, Daniel W; Ervin, Elizabeth; Washburn, Faith; Rickert, Regan; Singh, Tushar; Redd, John T

    2016-07-08

    On January 14, 2016, the Sierra Leone Ministry of Health and Sanitation was notified that a buccal swab collected on January 12 from a deceased female aged 22 years (patient A) in Tonkolili District had tested positive for Ebola virus by reverse transcription-polymerase chain reaction (RT-PCR). The most recent case of Ebola virus disease (Ebola) in Sierra Leone had been reported 4 months earlier on September 13, 2015 (1), and the World Health Organization had declared the end of Ebola virus transmission in Sierra Leone on November 7, 2015 (2). The Government of Sierra Leone launched a response to prevent further transmission of Ebola virus by identifying contacts of the decedent and monitoring them for Ebola signs and symptoms, ensuring timely treatment for anyone with Ebola, and conducting an epidemiologic investigation to identify the source of infection.

  15. 'Ah lef ma case fo God' : faith and agency in Sierra Leone's postwar reconciliation

    NARCIS (Netherlands)

    Millar, G.M.

    2012-01-01

    This article describes a qualitative ethnographic analysis of local experiences of truth-telling performances within Sierra Leone's Truth and Reconciliation Commission. Whereas proponents of truth commissions claim that such processes promote postwar reconciliation, this study found that local

  16. Management of rice seed during insurgency : a case study in Sierra Leone

    NARCIS (Netherlands)

    Mokuwa, G.A.

    2015-01-01

    Keywords: Technography, Oryza glaberrima,  Oryza sativa, farmer hybrids, sub-optimal agriculture, farmer adaptive management, plant genetic resources, peace and extreme (wartime) conditions, local seed channels, selection for robustness, Sierra Leone, West Africa. Abstract Moku

  17. Sierra Leone Journal of Biomedical Research Vol. 2 (1) pp. 70-74 ...

    African Journals Online (AJOL)

    2010-06-15

    Jun 15, 2010 ... 1Department of Biochemistry, College of Science, Engineering and Technology, Osun State University, ... function parameters in malaria patients in Freetown, Sierra Leone. ..... Message From Genetic Diversity (2nd Edition).

  18. SIERRA Low Mach Module: Fuego Theory Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    The SIERRA Low Mach Module: Fuego along with the SIERRA Participating Media Radiation Module: Syrinx, henceforth referred to as Fuego and Syrinx, respectively, are the key elements of the ASCI fire environment simulation project. The fire environment simulation project is directed at characterizing both open large-scale pool fires and building enclosure fires. Fuego represents the turbulent, buoyantly-driven incompressible flow, heat transfer, mass transfer, combustion, soot, and absorption coefficient model portion of the simulation software. Syrinx represents the participating-media thermal radiation mechanics. This project is an integral part of the SIERRA multi-mechanics software development project. Fuego depends heavily upon the core architecture developments provided by SIERRA for massively parallel computing, solution adaptivity, and mechanics coupling on unstructured grids.

  19. Synoptic and mesoscale controls on Sierra Nevada rain shadow intensity

    Science.gov (United States)

    Hatchett, B.; Kaplan, M.; Rutz, J. J.; Garner, C.

    2016-12-01

    The Sierra Nevada of California casts one of the world's greatest rain shadows with windward-leeside precipitation differences approaching an order of magnitude. Leeside rivers and terminal lakes provide critical water resources for ecosystem services and human consumptive use in this water-limited environment. They also offer important archives of paleohydroclimatic change. Understanding the drivers of rain shadow intensity represents an important step in properly evaluating how leeside hydrology will respond to projected climate change and for interpreting increasingly well spatially distributed paleoproxy evidence of past hydroclimates. Recent theoretical and modeling studies have shown rain shadow intensity to be controlled by multiscalar dynamics during storms such as the vertical structure of mountain waves, the presence of mid-level moisture, and position of the warm sector with respect to the mountain crest. Here, we provide a 35-year station-based climatology of strong and weak rain shadow events for the central Sierra Nevada during extended winter (November-April). Wetter (drier) years in leeside basins are characterized by higher (lower) fractions of lee-crest precipitation suggesting weaker (stronger) rain shadow effects during precipitation events. In general, as contributions of precipitation on the climatological top 5% of wet days increases, rain shadow intensity decreases. This suggests a key role for atmospheric rivers in weakening the rain shadow. A separate population of very dry years is found, regardless of number of dry days, when no precipitation is contributed by the climatological top 5% of wet days. These years show stronger rain shadow effects with few exceptions. Using the North American Regional Reanalysis and both surface and satellite-based remote sensing data in conjunction with the derived rain shadow climatology, we demonstrate the additional importance of atmospheric rivers, offshore and upstream mesoscale convection, and

  20. Los recursos humanos en un espacio natural protegido: Sierra Nevada

    Directory of Open Access Journals (Sweden)

    Ma. Enriqueta Cózar

    2000-01-01

    Full Text Available Sierra Nevada, como todas las áreas de montaña españolas y gran parte del territorio interior andaluz, ha experimentado durante el siglo XX un considerable retroceso demográfico. La población con la que llega al umbral del siglo XXI es una cuarta parte más pequeña que la registrada en 1900 y un tercio inferior a la de 1950. Diversos y complejos factores, tanto internos como externos al área de montaña, de carácter más económico que demográfico, fueron los desencadenantes de una fuerte emigración. La gran pérdida de población ha originado cambios trascendentales en la demografía y en la actividad económica de Sierra Nevada. En la actualidad, la población de este espacio protegido se caracteriza por una desequilibrada distribución en el territorio, un escaso crecimiento natural, un acelerado envejecimiento y una actividad mayoritariamente terciaria. La declaración, en Julio de 1989, como espacio natural protegido bajo la figura de Parque Natural, y la más reciente de Parque Nacional, apenas ha modificado la inercia demográfica regresiva de la mayor parte de sus municipios; tan sólo se ha podido apreciar una cierta tendencia a la estabilización demográfica de la población total del macizo

  1. The paleoenvironment of the "Sierra de la Primavera

    Science.gov (United States)

    Maciel, R.; Peña, L.; Rosas, J.

    2009-04-01

    The paleoenvironment of the "Sierra de la Primavera" (SP) Jalisco Mexico, was studied with paleontology, tephrachronology, strato-tectonic, geochronology and climatology techniques. It was created between 126,000 and 27,000 years ago (late Pleistocene) by more than 22 domes and a caldera (110 +- 15 thousand years). There are fault and fractures with a NNE and NNW trends, with up of four reactivation periods. Historically, seismic events have been registered around the caldera. Volcanic and tectonic activities have contributed to the modification of the morphology. The evidence of an intermittent paleolake formed into the caldera, are 24 strata are built on tephras, fluvial and vulcano-lacustres deposits, (> 51 m thick), present 2o to 35o leanings. The central part of the paleolake has raised more than 149 m which was caused by the reappearance of the magmatic chamber, it and the climatic changes disappeared the paleolake. There are layers of gigantic pomez and strata with carbon whith remaining from pines (ones, aciculas and branches). The method of 14C used in fossils report an age of 38,170 to 39,000 years BP. They are classified as remainings of Pinus durangensis Martínez, Pinus leiophylla Schiede ex Schltdl. & Cham., Pinus montezumae Lamb., Pinus luzmariae Pérez de la Rosa, Pinus teocote Schltdl. & Cham.y Pinus douglasiana Martínez. This community of pines was moved of SP to the Sierra de Bolaños (SB), 177 km northeast and 850 m higher (25000 masl), it is climatologically more humid and colder than the SP. This implies a movement in the border of the vegetation, associated to global climatic changes. Using the community of pines like bioindicator, it is inferred that the temperature in the SP has increased from 2 to 3 C and the precipitation has decreased between 100 and 200 mm from the late Pleistocene on. The predominant pine wood of its early years is now pine - Encino.

  2. Eastern Pacific Ocean Conference

    Science.gov (United States)

    The promotion of interaction among investigators of all oceanographic disciplines studying the eastern Pacific Ocean was the goal of the 1990 Eastern Pacific Ocean Conference (EPOC), held October 17-19 on the snow-covered slopes of Mt. Hood, Oreg. Thirty oceanographers representing all disciplines attended.Dick Barber, Duke University Marine Lab, Beaufort, N.C., chaired a session on the eastern equatorial Pacific Ocean, emphasizing issues related to biological activity. Steve Ramp of the Naval Postgraduate School in Montery, Calif., chaired a session on recent results from northern and central California experiments. On October 19, following an early morning earthquake, a business meeting and discussions regarding a collaboration in future experiments were held.

  3. Petrographical and geochemical characterization and deformation conditions of the San Cristobal pluton, Sierra de Velasco, La Rioja, Argentina; Caracterizacion petrografica y geoquimica y condiciones de deformacion del pluton San Cristobal, Sierra de Velasco, La Rioja, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Bellos, L.I.; Toselli, A.J.; Rossi, J.N.; Grosse, P.; Rosa, J.D. de la; Castro, A.

    2010-07-01

    The San Cristobal pluton is a 35 km2 granitic body that outcrops at the southestern tip of the Sierra de Velasco, located west of La Rioja city, Argentina. It is formed by monzogranites and syenogranites, together with scarce granodiorites, with medium to fine-grained, equigranular to slightly porphyritic textures. Their mineral assemblage consists of quartz + microcline + plagioclase + biotite {+-} muscovite + zircon + apatite + magnetite. The granite contains dioritic to tonalitic mafic enclaves. The central and eastern parts of the granite have been deformed by the NNW-SSE trending South Mylonitic shear zone formed by mylonitic rocks. The metamorphic host-rock is represented by scarce greenschist facies xenoliths and hornfels with the high T/P assemblage K-feldspar - cordierite - biotite {+-} sillimanite. The granites are calc-alkaline, weak- to moderately peraluminous, and formed as part of a continental magmatic arc developed along the active margin of western Gondwana during the Early Paleozoic. The depth of emplacement of the San Cristobal pluton is estimated at {approx}12 km. (Author).

  4. SierraDNA – Demonstrating the Usefulness of Direct ILS Database Access

    Directory of Open Access Journals (Sweden)

    James Padgett

    2015-10-01

    Full Text Available Innovative Interface’s Sierra(™ Integrated Library System (ILS brings with it a Database Navigator Application (SierraDNA - in layman's terms SierraDNA gives Sierra sites read access to their ILS database. Unlike the closed use cases produced by vendor supplied APIs, which restrict Libraries to limited development opportunities, SierraDNA enables sites to publish their own APIs and scripts based upon custom SQL code to meet their own needs and those of their users and processes. In this article we give examples showing how SierraDNA can be utilized to improve Library services. We highlight three example use cases which have benefited our users, enhanced online security and improved our back office processes. In the first use case we employ user access data from our electronic resources proxy server (WAM to detect hacked user accounts. Three scripts are used in conjunction to flag user accounts which are being hijacked to systematically steal content from our electronic resource provider’s websites. In the second we utilize the reading histories of our users to augment our search experience with an Amazon style “People who borrowed this book also borrowed…these books” feature. Two scripts are used together to determine which other items were borrowed by borrowers of the item currently of interest. And lastly, we use item holds data to improve our acquisitions workflow through an automated demand based ordering process. Our explanation and SQL code should be of direct use for adoption or as examples for other Sierra customers willing to exploit their ILS data in similar ways, but the principles may also be useful to non-Sierra sites that also wish to enhancement security, user services or improve back office processes.

  5. An investigation into the new emerging social sub group of professional Muslim women in Sierra Leone

    OpenAIRE

    Taqi, Fatmatta, B.

    2010-01-01

    Sierra Leone is in transition to peace and development, from a previous decade long civil war. Educated Muslim women appear to have a great deal of expression, interest and passion to offer the process. The study investigates the new emerging social sub group of professional Muslim women in Sierra Leone society and explores their views and experiences of identifying and attempting to overcome the burdens of patriarchy, oppression and exploitation perpetrated by religious, social and cultural ...

  6. Human papillomavirus (HPV) knowledge and prevention practices among Sierra Sur, Oaxaca college students

    OpenAIRE

    Bustamante Ramos, Gisela Mayra; Instituto de Investigación sobre la Salud Pública (IISSP), Universidad de la Sierra Sur, Oaxaca, México; Martínez-Sánchez, Abisai; Instituto de Investigación sobre la Salud Pública (IISSP), Universidad de la Sierra Sur, Oaxaca, México; Tenahua-Quitl, Inés; Facultad de Enfermería, Benemérita Universidad Autónoma de Puebla, México; Jiménez, Concepción; Estudiante de la licenciatura en Enfermería, Instituto de Investigación sobre la Salud Pública (IISSP), Universidad de la Sierra Sur, Oaxaca, México; López Mendoza, Yarely; Estudiante de la licenciatura en Enfermería, Instituto de Investigación sobre la Salud Pública (IISSP), Universidad de la Sierra Sur, Oaxaca, México

    2016-01-01

    Introduction. Human papillomavirus (HPV) causes the world’s most important sexually transmitted infection and is considered the main agent for cervical cancer. Youngsters are most vulnerable as they usually begin sexual relations without protection. Objectives. To describe students’ knowledge of human papillomavirus infection prevention at Sierra Sur, Oaxaca University. Design. Quantitative, descriptive cross-sectional study. Place. Sierra Sur, Oaxaca, Mexico. Participants. University student...

  7. Ecología de la fauna silvestre de la sierra nevada y la Sierra del Ajusco

    Directory of Open Access Journals (Sweden)

    D. Granados Sánchez

    2004-01-01

    Full Text Available Se presenta un estudio sobre la fauna silvestre de la Sierra del Ajusco y la Sierra Nevada, localizadas dentro de la Faja Volcánica Transmexicana (FVT, en la porción oriental del límite meridional de la Cuenca de México. La enorme riqueza biológica de esta zona que rodea la zona metropolitana de la ciudad de México, uno de los mayores complejos urbanos del mundo, ha sobrevivido durante décadas al impacto de la urbanización de las áreas forestales, explotación de recursos naturales, contaminación, cacería, incendios y pastoreo. A pesar de esto, se desconocen muchos de los factores que regulan la dinámica de los ecosistemas en esta región. Con relación a la fauna silvestre la carencia de información es mucho más evidente, aspectos elementales como la diversidad de especies, las interacciones ecológicas, la función de los organismos en el ecosistema, las condiciones de estrés a que están sometidos, han sido poco explorados. En esta investigación se recurrió a observaciones de campo y a la consulta de diferentes fuentes bibliográficas para estimar la riqueza de especies de mamíferos, aves, reptiles y anfibios; las relaciones ecológicas entre los mismos y las consecuencias de la modificación de su hábitat producto de las actividades humanas.

  8. Comparación de índices de estrés hídrico, a partir de información captada por el sensor MODIS, en la región pampeana argentina

    Directory of Open Access Journals (Sweden)

    Patricia Vazquez

    2013-01-01

    Full Text Available La Región Pampeana Argentina manifiesta una tenencia a la expansión agrícola que aumenta los riesgos económicos por su elevada dependencia de las condiciones meteorológicas. A fin de mejorar las predicciones sobre el comportamiento de los cultivos, en este trabajo se estudia la sensibilidad de diferentes índices de estrés hídrico a la disponibilidad de agua en el suelo (DAS, mediante el uso de imágenes satelitales en la mencionada región. Se analizaron tres índices a partir de datos de campañas de terreno en diferentes cultivos, conjuntamente con información satelital. Dos de ellos, Crop Water Stress Index (CWSI y Water Deficit Index (WDI, combinan información de satélite con datos de estaciones meteorológicas. El tercero, Temperature–Vegeta- tion Dryness Index (TDVI, utiliza solamente información de satélite. Se observó que el TDVI es el que mejor resultados arroja (r2 = 0,92. Se concluye que este índice es el que permite generar diagnósticos adecuados por ser el más sensible a cambios en la DAS.

  9. Farming Families' Access to Water in the Pampa Region: A multidimensional analysis El acceso al agua de los agricultores familiares de la región pampeana: Un análisis multidimensional

    Directory of Open Access Journals (Sweden)

    Alejandra Moreyra

    2012-01-01

    Full Text Available This paper presents the conceptual and methodological perspective of participatory action research with an interdisciplinary approach. Specifically, this research examines different dimensions that condition the access to water for farming families in the Pampa region. Together with famers and extension workers, we defined the problems, considering that water as mediator of social relations among different actors involved - resource appropriation for irrigation and agricultural production and other sectors' productions, family consumption and sewage-. In the last sections of the document, the research team presents observations, analysis and reflections on the progress of field work we have done so farEste artículo presenta, en su primera parte, el enfoque conceptual y metodológico de un proyecto de investigación-acción participativa abordado de forma interdisciplinaria. La investigación refiere a las diferentes dimensiones que condicionan el acceso al agua de los agricultores familiares en distintos sitios de la región pampeana. La problemática se define en la dinámica con los actores involucrados, considerando que el agua mediatiza las relaciones sociales -de apropiación para el riego y la producción agrícola y de otros sectores, el consumo y la eliminación de residuos- entre diferentes actores. En las últimas secciones se presentan algunas de las observaciones y reflexiones del equipo de investigación en base a los primeros avances del trabajo de campo

  10. Eficiencia agronómica del azufre elemental relativa a una fuente azufrada soluble en trigo en la Región Pampeana Agronomic efficiency of elemental sulphur in wheat relative to a soluble sulphur source in the Pampas Region

    Directory of Open Access Journals (Sweden)

    Martin Torres Duggan

    2010-07-01

    Full Text Available La eficiencia agronómica del azufre elemental (AE en relación a fuentes azufradas solubles y sulfatadas, depende de su reactividad (e.g. tamaño de partícula y de las condiciones edafo-climáticas. Para las condiciones de la Región Pampeana algunas publicaciones sugieren que el AE puede ser una fuente de S tan efectiva como las fuentes solubles, aunque la información no concluyente. Se hipotetiza que en las condiciones de la Región Pampeana, ambas fuentes poseen similar eficiencia agronómica en la mayoría de los años. Los objetivos del trabajo fueron: i. Evaluar la respuesta al agregado de S con una fuente reactiva de AE en relación a un fertilizante azufrado sulfatado, aplicado en trigo en diferentes dosis y en distintas condiciones edafo-climáticas; ii. Comparar, para el conjunto de experimentos, la eficiencia agronómica del S aplicado con las distintas fuentes. iii. Relacionar las respuestas a la fertilización azufrada con variables de suelo y clima. Se realizaron ocho ensayos de campo durante dos años consecutivos en lotes de producción ubicados en la Región Pampeana. Se aplicó un diseño en bloques completos aleatorizados con cuatro o seis repeticiones en un arreglo factorial de tratamientos (factor 1: fuente azufrada, factor 2: dosis de S. Los tratamientos fueron: un testigo absoluto; fertilización con AE micronizado (95% de S en dos niveles de dosis y fertilización con sulfato de amonio granulado (SA, 24% S, también en dos niveles de dosis. Las dosis evaluadas fueron 10 y 30 kg ha-1 de S (año 1 y 15 y 30 kg ha¹ (año 2. La fertilización azufrada afectó significativamente (p0,05 en la mayoría de los sitios. La dosis más baja (10 o 15 kg ha-1 fue suficiente para cubrir el requerimiento de S del cultivo. Se observó una asociación positiva entre las respuestas y el contenido de MO del suelo y las precipitaciones (macollaje y total del ciclo y una relación inversa con el contenido de S-SO4(2- disponibles a la

  11. Anomalías del campo gravitatorio y magnético terrestre en la sierra de Socoscora, provincia de San Luis Earth gravity and magnetic field anomalies in the Sierra of Socoscora, San Luis province

    Directory of Open Access Journals (Sweden)

    J Kostadinoff

    2003-12-01

    Full Text Available La sierra de Socoscora se ubica en forma meridiana y se manifiesta como un escalón al noroeste de la Sierra Grande de San Luis. En la sierra de Socoscora las rocas del basamento están representadas por metamorfitas de alto grado con escasos afloramientos de metabasitas. Las mediciones del campo gravitatorio y magnético indican la presencia de un volumen mayor de estas rocas en su subsuelo. Los excesos de masa en esta sierra se hallan definidas por anomalías gravimétricas de Bouguer (residuales positivas similares a las encontradas en la Sierra Grande de San Luis. La magnetometría indica, a partir de las respuestas positivas, la existencia de rocas máficas con concentraciones anómalas de minerales magnéticos.The Sierra de Socoscora is a north - south trending mountain range, located nortwest of the Sierra Grande of San Luis. The basament is constituted by high grade metamorphic rocks with few associated metabasites. Earth gravity and magnetic field measurements are indicative of the presence of bigger volumes of mafic rocks below the surface, which carry anomalous concentrations of ferromagnetic and/or paramagnetic minerals (magnetite and/or sulfides. An excess of mass below this Sierra is shown by Bouguer gravimetric anomalies with magnitudes similar to those measured in the Sierra Grande de San Luis. Positive magnetic anomalies are indicative of the presence of mafic rocks with anomalous concentrations of magnetic minerals.

  12. Datacion U-PB por LA-ICP-MS de diques graniticos del ciclo pampeano, sierra de Mojotoro, Cordillera Oriental LA-ICP-MS U-Pb age from granitic dikes fr om the Pampean cycle, Sierra de Mo/otoro, Cordillera Oriental

    Directory of Open Access Journals (Sweden)

    Pamela A Aparicio González

    2011-03-01

    Full Text Available El objetivo del presente trabajo es dar a conocer los resultados de dataciones U-Pb por el método LA-ICP-MS sobre circones procedentes de diques de pórfido granítico que intruyen a la Formación Chachapoyas (nom. nov. en la sierra de Mojotoro, en el noroeste de Argentina. Para ello, se analizaron 20 circones euhedrales de morfologías prismáticas aciculares y transparentes. Los resultados obtenidos son concordantes en ocho granos de circones permitiendo definir una edad de cristalización para el dique de 533 ± 2 Ma. Si se asocian los nuevos datos con otros de rocas ígneas de edades similares localizadas en otros sectores de la Cordillera Oriental, se confirma un evento magmàtico ácido ocurrido en el Cámbrico inferior.A zircon U-Pb age obtained with the LA-ICP-MS method is presented for a granite porphyry from Chachapoyas Formation (nom. nop., sierra de Mojotoro, NW Argentina. 20 euhedral zircons with acicular prismatic and transparent morphology were analyzed. The data obtained is concordant in eight zircons grains and show a crystallization age of 533 ± 2 Ma. The new data could be associated with igneous rocks of similar ages located in the Eastern Cordillera, and suggest an acid magmatic event during the Lower Cambrian. This outcrop represents the southern expression of the Pampean magmatic arc in the NW of Argentina.

  13. Transitioning from a U.N. Observer Mission to a Robust Peacekeeping Operation: Lessons from Sierra Leone

    Science.gov (United States)

    2007-11-02

    U.N.CHAPTER VI OBSERVER MISSION TO A ROBUST PEACEKEEPING OPERATION: LESSONS FROM SIERRA LEONE 9. Personal Authors: Peter V. Londono, CIV 10.Type of...necessarily endorsed by the NWC or the Department of the Navy. 14. Ten key words that relate to your paper: Peacekeeping, U.N., Sierra Leone , UNOMSIL...UNAMSIL, RUF, Peace Enforcement, Operation Relief Focus, ECOWAS, ECOMOG 15.Abstract: U.N. peacekeeping operations in Sierra Leone have special

  14. DISCOVERING BEIJING Eastern Promise

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Dongcheng District, literally meaning eastern city, covers Beijing’s downtown area to the northeast of the central axis of old Beijing. The district has a total area of 25 square km and a population of 600,000. With a large number of cultural and historical sites and tourist attractions,

  15. Eastern Spruce Dwarf Mistletoe

    Science.gov (United States)

    F. Baker; Joseph O' Brien; R. Mathiasen; Mike Ostry

    2006-01-01

    Eastern spruce dwarf mistletoe (Arceuthobium pusillum) is a parasitic flowering plant that causes the most serious disease of black spruce (Picea mariana) throughout its range. The parasite occurs in the Canadian provinces of Saskatchewan, Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia, Prince Edward Island, and Newfoundland; in the Lake States of Minnesota,...

  16. Eastern Frequency Response Study

    Energy Technology Data Exchange (ETDEWEB)

    Miller, N.W.; Shao, M.; Pajic, S.; D' Aquila, R.

    2013-05-01

    This study was specifically designed to investigate the frequency response of the Eastern Interconnection that results from large loss-of-generation events of the type targeted by the North American Electric Reliability Corp. Standard BAL-003 Frequency Response and Frequency Bias Setting (NERC 2012a), under possible future system conditions with high levels of wind generation.

  17. A distinctive new subspecies of Scytalopus griseicollis (Aves, Passeriformes, Rhinocryptidae) from the northern Eastern Cordillera of Colombia and Venezuela

    Science.gov (United States)

    Avendaño, Jorge Enrique; Donegan, Thomas M.

    2015-01-01

    Abstract We describe a new subspecies of Pale-bellied Tapaculo Scytalopus griseicollis from the northern Eastern Cordillera of Colombia and Venezuela. This form differs diagnosably in plumage from described subspecies Scytalopus griseicollis griseicollis and Scytalopus griseicollis gilesi and from the latter in tail length. It is also differentiated non-diagnosably in voice from both these populations. Ecological niche modelling analysis suggests that the new subspecies is restricted to the Andean montane forest and páramo north of both the arid Chicamocha valley and the Sierra Nevada del Cocuy. PMID:26085800

  18. Monitoring lichens diversity and climatic change in Sierra Nevada (Spain

    Directory of Open Access Journals (Sweden)

    Fernández Calzado, M.ª R.

    2013-12-01

    Full Text Available Lichens are common organisms in high mountain zones, where they play an important role in ecosystem balance. In recent years, the increasing interest in understanding more about their interactions with abiotic factors has prompted several investigations, some of which have proved their value as bioindicators of climatic conditions. In this context, focusing on climatic change effects on high mountain vascular plants and supported by the Global Observation Research Initiative in Alpine Environments project (GLORIA, we have monitored for the first time the lichens biodiversity in Sierra Nevada with the intention of studying the alterations caused by the process of climatic change. The aim of this paper is to explain the monitoring experience developed on the massif and contribute to the first results from the biodiversity and statistical analysis of the sampling data.Los líquenes son organismos comunes en las zonas de alta montaña donde juegan un importante papel en el equilibrio de los ecosistemas. En los últimos años, el creciente interés por entender más acerca de sus interacciones con los factores abióticos ha motivado diversas investigaciones, algunas de las cuales han demostrado su valor como bioindicadores de las condiciones climáticas. En este contexto, centrándonos en los efectos del cambio climático en plantas vasculares de alta montaña y respaldados por el proyecto “Iniciativa para la investigación y el seguimiento global de los ambientes alpinos (GLORIA”, se ha monitorizado por primera vez la diversidad de líquenes en Sierra Nevada con la intención de estudiar las posibles alteraciones que esta pueda sufrir causadas por el proceso de cambio climático. El objetivo de este artículo es el de dar a conocer la experiencia de seguimiento en el macizo y aportar los primeros resultados procedentes del análisis, tanto de la biodiversidad como estadístico, de los datos de muestreo.

  19. Maintaining effective mass drug administration for lymphatic filariasis through in-process monitoring in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Hodges Mary H

    2012-10-01

    Full Text Available Abstract Background Since 2007 Sierra Leone has conducted mass drug administration (MDA for the elimination of lymphatic filariasis (LF implemented by unpaid community health volunteers (CHVs. Other health campaigns such as Mother and Child Health Weeks (MCHW pay for services to be implemented at community level and these persons are then known as community health workers (CHWs. In 2010, the LF MDA in the 12 districts of the Southern, Northern and Eastern Provinces un-expectantly coincided with universal distribution of Long Lasting Insecticide Treated Nets (LLITNs during the MCHW. In-process monitoring of LF MDA was performed to ensure effective coverage was attained in hard to reach sites (HTR in both urban and rural locations where vulnerable populations reside. Methods Independent monitors interviewed individuals eligible for LF MDA and tallied those who recalled having taken ivermectin and albendazole, calculated program coverage and reported results daily by phone. Monitoring of coverage in HTR sites in the 4 most rapidly urbanizing towns was performed after 4 weeks of LF MDA and again after 8 weeks throughout all 12 districts. End process monitoring was performed in randomly selected HTR sites not previously sampled throughout all 12 districts and compared to coverage calculated from the pre-MDA census and reported treatments. Results Only one town had reached effective program coverage (≥80% after 4 weeks following which CHWs were recruited for LF MDA in all district headquarter towns. After 8 weeks only 4 of 12 districts had reached effective coverage so LF MDA was extended for a further month in all districts. By 12 weeks effective program coverage had been reached in all districts except Port Loko and there was no significant difference between those interviewed in communities versus households or by sex. Effective epidemiological coverage (≥65% was reported in all districts and overall was significantly higher in males versus

  20. Eruption Dynamics and Flow Morphology during the 2005 Sierra Negra Eruption, Galapagos Islands

    Science.gov (United States)

    Rader, E.; Harpp, K.; Geist, D.

    2006-12-01

    Sierra Negra volcano began erupting on October 22nd, 2005. The eruption lasted nine days and provided an opportunity to examine emplacement of lava flows and their morphology. During the first two days, fire fountaining produced a broad, unchannelized flow that coated the northern caldera wall and benches directly below the vents as it moved onto the eastern caldera floor. After the first day of the eruption, the caldera floor a'a flow grew primarily by inflation, lateral spreading along linear upwelling regions, and pahoehoe breakouts at the perimeter. Simultaneously, four 4km long rootless flows formed on the northern flanks of the volcano, supplied by spatter from the vents inboard of the caldera rim. Samples from different morphological types of lava from the caldera floor, bench, and outer flanks were collected and examined by BSE imaging. Transitions from pahoehoe to a'a and back to pahoehoe were observed in a low viscosity flow on the caldera bench that cascaded over a steep escarpment. Plagioclase microlite content in the bench flow varies little, with 27% in pahoehoe and 33% in a'a, on average. Consequently, we propose that the transformation was driven by changes in strain rate rather than cooling. As the lava first flowed over the bench edge, the increased strain rate caused it to become a'a. The elevation drop was small enough, however, that the flow remained sufficiently hot to revert to pahoehoe as it pooled on the flat surface at the base of the drop; comparable flows have been described on Kilauea. Similarly, pahoehoe breakouts from the caldera floor a'a flow were driven by pressure from the inflating flow, causing well-insulated lava to emerge from the a'a body as pahoehoe. Quenched lava collected from the incandescent breakouts have higher crystal contents than those collected closer to the vents, indicating that they experienced ~30° cooling during transport within the inflating flow. At the southern tip of the caldera floor flow, several km

  1. Straining: Young Men Working through Waithood in Freetown, Sierra Leone

    Directory of Open Access Journals (Sweden)

    Brandon Finn

    2015-01-01

    Full Text Available Young men in precarious situations of persistent un(deremployment in post-civil war Freetown, Sierra Leone are depicted in popular and policy debate as “stuck” economically or “dangerous” and prone to violence. In the present paper, by contrast, we draw on young men’s explanations of their work and livelihood struggles as “straining.” We explore the logic of straining, its innovations and demands, and its geography across the city, especially where acts of straining interface with the prohibition and criminalisation of informal trading. We argue that straining innovates and endures because of (not despite young men’s marginalisation and limited autonomy and power. In this context, young men build forms of provisional agency and enact dynamic forms of waithood, in their strategies to earn a living to try to support their families and to negotiate a transition from youth to manhood. Drawing on this research, we argue for a more complex understanding of young men at work in Freetown, in particular, and of the “youth bulge,” in general, in African cities.

  2. California spotted owls: Chapter 5 in Managing Sierra Nevada forests

    Science.gov (United States)

    Roberts, Suzanne C.; Brooks, Matthew L.

    2012-01-01

    California spotted owls (Strix occidentalis occidentalis) are habitat specialists that are strongly associated with late-successional forests. For nesting and roosting, they require large trees and snags embedded in a stand with a complex forest structure (Blakesley et al. 2005, Gutiérrez et al. 1992, Verner et al. 1992b). In mixedconifer forests of the Sierra Nevada, California spotted owls typically nest and roost in stands with high canopy closure (≥75 percent) [Note: when citing studies, we use terminology consistent with Jennings et al. (1999), however, not all studies properly distinguish between canopy cover and closure and often use the terms interchangeably (see chapter 14 for clarification)] and an abundance of large trees (>24 in (60 cm) diameter at breast height [d.b.h.]) (Bias and Gutiérrez 1992, Gutiérrez et al. 1992, LaHaye et al. 1997, Moen and Gutiérrez 1997, Verner et al. 1992a). The California spotted owl guidelines (Verner et al. 1992b) effectively summarized much of the information about nesting and roosting habitat. Since that report, research on the California spotted owl has continued with much of the new information concentrated in five areas: population trends, barred owl (Strix varia) invasion, climate effects, foraging habitat, and owl response to fire.

  3. específico en la sierra norte de Sevilla

    Directory of Open Access Journals (Sweden)

    Rafael Garzón García

    2008-01-01

    Full Text Available La primera parte del artículo ofrece una visión panorámica de la política de fomento del uso público en la Red de Espacios Naturales Protegidos de Andalucía desde su origen hasta nuestros días, con especial incidencia en cuestiones tales como el papel preponderante asumido por la figura de Parque Natural, el desequilibrio territorial de las intervenciones planteadas, o la necesaria ordenación y planificación de la actividad. Ello conforma el contexto idóneo para abordar, en segunda instancia, un análisis particularizado de la gestión del uso público en el Parque Natural Sierra Norte de Sevilla. La elección de este ámbito territorial se fundamenta tanto en sus especiales condicionantes para el fomento de esta línea de acción (privilegiada situación, existencia de una demanda tradicional asociada a determinados enclaves, propiedad de la tierra… como en la singular gestión desarrollada desde la declaración del parque, destacando las nuevas perspectivas e incertidumbres que parecen despertarse a partir del impulso y aprobación de una planificación específica

  4. SIERRA Multimechanics Module: Aria User Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    Aria is a Galerkin fnite element based program for solving coupled-physics problems described by systems of PDEs and is capable of solving nonlinear, implicit, transient and direct-to-steady state problems in two and three dimensions on parallel architectures. The suite of physics currently supported by Aria includes thermal energy transport, species transport, and electrostatics as well as generalized scalar, vector and tensor transport equations. Additionally, Aria includes support for manufacturing process fows via the incompressible Navier-Stokes equations specialized to a low Reynolds number ( %3C 1 ) regime. Enhanced modeling support of manufacturing processing is made possible through use of either arbitrary Lagrangian- Eulerian (ALE) and level set based free and moving boundary tracking in conjunction with quasi-static nonlinear elastic solid mechanics for mesh control. Coupled physics problems are solved in several ways including fully-coupled Newton's method with analytic or numerical sensitivities, fully-coupled Newton- Krylov methods and a loosely-coupled nonlinear iteration about subsets of the system that are solved using combinations of the aforementioned methods. Error estimation, uniform and dynamic h -adaptivity and dynamic load balancing are some of Aria's more advanced capabilities. Aria is based upon the Sierra Framework.

  5. Sierra Nevada Batholith: The batholith was generated within a synclinorium.

    Science.gov (United States)

    Bateman, P C; Eaton, J P

    1967-12-15

    The Sierra Nevada batholith is localized in the axial region of a complex faulted synclinorium that coincides with a downfold in the Mohorovicic discontinuity and in P-wave velocity boundaries within the crust. Observed P-wave velocities are compatible with downward increase in the proportion of diorite, quartz diorite, and calcic granodiorite relative to quartz monzonite and granite in the upper crust, with amphibolite or gabbro-basalt in the lower crust, and with periodotite in the upper mantle. The synclinorium was formed in Paleozoic and Mesozoic strata during early and middle Mesozoic time in a geosyncline marginal to the continent. Granitic magmas are believed to have formed in the lower half of the crust at depths of 25 to 45 kilometers or more, primarily as a result of high radiogenic heat production in the thickened prism of crustal rocks. Magma was generated at different times in different places as the locus of down-folding shifted. It rose into the upper crust because it was less dense than rock of the same composition or residual refractory rocks. Refractory rocks and crystals that were not melted and early crystallized mafic minerals that settled from the rising magma thickened the lower crust. Wall and roof rocks settled around, and perhaps through, the rising magma and provided space for its continued rise. Erosion followed each magmatic episode, and 10 to 12 kilometers of rock may have been eroded away since the Jurassic and 7 to 10 kilometers since the early Late Cretaceous.

  6. Striving for excellence: nurturing midwives' skills in Freetown, Sierra Leone.

    Science.gov (United States)

    Ngongo, Carrie; Christie, Kate; Holden, Jude; Ford, Carolyn; Pett, Celia

    2013-10-01

    Midwives provide critical, life-saving care to women and babies. Effective midwives must be clinically competent, with the required knowledge, skills, and attitudes to provide quality care. Their success depends on an environment of supportive supervision, continuing education, enabling policies, and access to equipment and referral facilities. In Freetown, Sierra Leone, the Aberdeen Women's Centre launched a maternity unit with an emphasis on striving for excellence and providing ongoing professional development to its staff midwives. Its success was built upon fostering a sense of responsibility and teamwork, providing necessary resources, conforming to evidence-based standards, and building partnerships. An explicit philosophy of care was crucial for guiding clinical decision making. In its first two years of operation, the Aberdeen Women's Centre assisted 2076 births with two maternal deaths and 92 perinatal deaths. In-service education and supportive supervision facilitated the midwives' professional growth, leading to capable future leaders who are providing exemplary care to delivering mothers and their newborns in Freetown.

  7. El castillo de Penna Cadiella en la sierra de Benicadell

    Directory of Open Access Journals (Sweden)

    Navarro Oltra, Vicente Carlos

    2002-12-01

    Full Text Available In this article we try to locate the place where the castle of Penna Cadiella, mentioned in the Poem of Mio Cid could had been built. To this we reintroduce the hypothesis expressed in its time by P. Guichard regarding the castle's location on top of the Benicadell range of mountains (Valencia-Alicante and we provide new documentary and archaeological data. Likewise, we analyse the 371st chapter of Jaime I´s Crónica in which the battle fought for the possession of the above-mentioned castle by the troops of the Aragonese king against al-Azraq in the thirteenth century is narrated.

    En este trabajo se intenta localizar el lugar en el que pudo asentarse el castillo de Penna Cadiella mencionado en el Poema de Mío Cid. Para ello, se retoma la hipótesis que en su día planteara P. Guichard sobre su ubicación en la cima de la Sierra de Benicadell (Valencia-Alicante y se aportan nuevos datos documentales y arqueológicos. Asimismo, se analiza el capítulo 371 de la Crónica de Jaime I en el cual se relata la batalla que, por su posesión, libraron las tropas del rey aragonés contra al-Azraq a mediados del siglo XIII.

  8. SIERRA Multimechanics Module: Aria User Manual Version 4.46.

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-09-01

    Aria is a Galerkin fnite element based program for solving coupled-physics problems described by systems of PDEs and is capable of solving nonlinear, implicit, transient and direct-to-steady state problems in two and three dimensions on parallel architectures. The suite of physics currently supported by Aria includes thermal energy transport, species transport, and electrostatics as well as generalized scalar, vector and tensor transport equations. Additionally, Aria includes support for manufacturing process fows via the incompressible Navier-Stokes equations specialized to a low Reynolds number ( %3C 1 ) regime. Enhanced modeling support of manufacturing processing is made possible through use of either arbitrary Lagrangian- Eulerian (ALE) and level set based free and moving boundary tracking in conjunction with quasi-static nonlinear elastic solid mechanics for mesh control. Coupled physics problems are solved in several ways including fully-coupled Newton's method with analytic or numerical sensitivities, fully-coupled Newton- Krylov methods and a loosely-coupled nonlinear iteration about subsets of the system that are solved using combinations of the aforementioned methods. Error estimation, uniform and dynamic h -adaptivity and dynamic load balancing are some of Aria's more advanced capabilities. Aria is based upon the Sierra Framework.

  9. Seed germination of Sierra Nevada postfire chaparral species

    Science.gov (United States)

    Keeley, Jon E.; McGinnis, Thomas W.; Bollens, Kim A.

    2005-01-01

    The California chaparral community has a rich flora of species with different mechanisms for cuing germination to postfire conditions. Here we report further germination experiments that elucidate the response of several widespread shrub species whose germination response was not clear and include other species from the Sierra Nevada, which have not previously been included in germination studies. The shrubs Adenostoma fasciculatum and Eriodictyon crassifolium and the postfire annualMentzelia dispersa exhibited highly significant germination in response to smoke treatments, with some enhanced germination in response to heating as well. The shrubs Fremontodendron californicum and Malacothamnus fremontii were stimulated only by heat-shock treatments. Seeds buried in the soil for one year exhibited substantially higher germination for controls and most treatments. In the case of two postfire annuals, Mimulus bolanderi and M. gracilipes, germination of fresh seed was significantly greater with smoke or heating but after soil storage, over two-thirds of the control seeds germinated and treatment effects were not significant. These two annuals are generally restricted to postfire conditions and it is suggested that control germination of soil-stored seed may be a light-response (which was not tested here) as previously reported for another chaparral species in that genus.

  10. accidentes y otras causas violentas en la sierra de Sonora

    Directory of Open Access Journals (Sweden)

    Héctor Eloy Rivas Sánchez

    2005-01-01

    Full Text Available Este artículo presenta los resultados de una investigación sociológica cuyo objeto fue explorar el papel que ha jugado el modelo hegemónico de masculinidad en la ocurrencia de muertes derivadas de accidentes y varias formas de ejercicio de la violencia en una comunidad rural de la sierra de Sonora. Estos resultados difieren de aquellos que tradicionalmente los estudios de las masculinidades han mostrado para México y América Latina. El modelo dominante de masculinidad en las comunidades estudiadas no ha condicionado significativamente la ocurrencia de las muertes por accidentes y otras causas violentas. La responsabilidad, la disciplina y el respeto hacia las personas consideradas socialmente débiles (mujeres, ancianos y niños, principalmente son características que debe poseer un hombre de verdad en las comunidades estudiadas. El apego de los hombres a estas formas de comportamiento y su temor a perder honorabilidad como hombre de verdad si se desvían de estas normas de conducta los ha llevado a evitar una serie de prácticas temerarias que pudieron poner en riesgo su vida y la de otras personas.

  11. From Back-arc Drifting to Arc Accretion: the Late Jurassic-Early Cretaceous Evolution of the Guerrero Terrane Recorded by a Major Provenance Change in Sandstones from the Sierra de los Cuarzos, Central Mexico

    Science.gov (United States)

    Palacios Garcia, N. B.; Martini, M.

    2014-12-01

    The Guerrero terrane composed of Middle Jurassic-Early Cretaceous arc assemblages, were drifted from the North American continental mainland during lower Early Cretaceous spreading in the Arperos back arc basin, and subsequently accreted back to the continental margin in the late Aptian. Although the accretion of the Guerrero terrane represents one of the major tectonic processes that shaped the southern North American Pacific margin, the stratigraphic record related to such a regional event was not yet recognized in central Mexico. Due to the Sierra de los Cuarzos is located just 50 km east of the Guerrero terrane suture belt, its stratigraphic record should be highly sensitive to first order tectonic changes and would record a syn-tectonic deposits related to this major event. In that study area, were identified two main Upper Jurassic-Lower Cretaceous clastic units. The Sierra de los Cuarzos formation represents the lowermost exposed stratigraphic record. Sedimentary structures, sandstones composition, and U-Pb detrital zircon ages document that the Sierra de los Cuarzos formation reflects a vigorous mass wasting along the margin of the North American continental mainland, representing the eastern side of the Arperos back arc basin. Sandstones of the Sierra de los Cuarzos formation are free from detrital contributions related to the Guerrero terrane juvenile sources, indicating that the Arperos Basin acted like an efficient sedimentological barrier that inhibited the influence of the arc massifs on the continental mainland deposits. The Sierra de los Cuarzos formation is overlain by submarine slope deposits of the Pelones formation, which mark a sudden change in the depositional conditions. Provenance analysis documents that sandstones from the Pelones formation were fed by the mafic to intermediate arc assemblages of the Guerrero terrane, as well as by quartz-rich sources of the continental mainland, suggesting that, by the time of deposition of the Pelones

  12. Catálogo de la flora del Parque Natural de la Sierra de Mariola (Alicante-Valencia [Checklist of the Natural Park of Sierra de Mariola (Alicante-Valencia, Spain vascular flora

    Directory of Open Access Journals (Sweden)

    Jaume X. SOLER SIGNES

    2012-04-01

    Full Text Available Se presenta la lista actualizada de flora vascular presente en el Parque Natural de la Sierra de Mariola (Alicante-Valencia.SUMMARY. The checklist of the vascular flora of the Natural Park of Sierra de Mariola is here presented.

  13. Photo series for quantifying forest fuels in Mexico: montane subtropical forests of the Sierra Madre del Sur and temperate forests and montane shrubland of the northern Sierra Madre Oriental

    Science.gov (United States)

    Jorge E. Morfin-Rios; Ernesto Alvarado-Celestino; Enrique J. Jardel-Pelaez; Robert E. Vihnanek; David K. Wright; Jose M. Michel-Fuentes; Clinton S. Wright; Roger D. Ottmar; David V. Sandberg; Andres Najera-Diaz

    2008-01-01

    Single wide-angle and stereo photographs display a range of forest ecosystems conditions and fuel loadings in montane subtropical forests of the Sierra Madre del Sur and temperate forests and montane shrubland of the northern Sierra Madre Oriental of Mexico. Each group of photographs includes inventory information summarizing overstory vegetation composition and...

  14. Sierra/SolidMechanics 4.22 user's guide : addendum for shock capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    2011-10-01

    This is an addendum to the Sierra/SolidMechanics 4.22 User's Guide to document additional capabilities that are available for use in the Presto{_}ITAR code that are not available for use in the standard version of Sierra/SolidMechanics (Sierra/SM). Presto{_}ITAR is an enhanced version of Sierra/SM that provides capabilities that make it regulated under the U.S. Department of State's International Traffic in Arms Regulations (ITAR) export-control rules. This code is part of the Vivace product, and is only distributed to entities that comply with ITAR regulations. The enhancements primarily focus on material models that include an energy-dependent pressure response, appropriate for very large deformations and strain rates. Since this is an addendum to the standard Sierra/SolidMechanics User's Guide, please refer to that document first for general descriptions of code capability and use. This addendum documents material models and element features that support energy-dependent material models.

  15. Sierra/SolidMechanics 4.22 user's guide : addendum for shock capabilities.

    Energy Technology Data Exchange (ETDEWEB)

    2011-10-01

    This is an addendum to the Sierra/SolidMechanics 4.22 User's Guide to document additional capabilities that are available for use in the Presto{_}ITAR code that are not available for use in the standard version of Sierra/SolidMechanics (Sierra/SM). Presto{_}ITAR is an enhanced version of Sierra/SM that provides capabilities that make it regulated under the U.S. Department of State's International Traffic in Arms Regulations (ITAR) export-control rules. This code is part of the Vivace product, and is only distributed to entities that comply with ITAR regulations. The enhancements primarily focus on material models that include an energy-dependent pressure response, appropriate for very large deformations and strain rates. Since this is an addendum to the standard Sierra/SolidMechanics User's Guide, please refer to that document first for general descriptions of code capability and use. This addendum documents material models and element features that support energy-dependent material models.

  16. 77 FR 45 - Endangered and Threatened Wildlife and Plants; 90-Day Finding on a Petition To List Sierra Nevada...

    Science.gov (United States)

    2012-01-03

    ... that Sierra Nevada red fox is threatened by salmon poisoning disease, disease transmission by domestic... bloody diarrhea, with a 90 percent mortality rate if untreated (Rikihisa et al. 1991, p. 1928). The... warranted due to transmission of SPD. We will review the possible effects of SPD to Sierra Nevada red fox...

  17. Airborne Pesticides as an Unlikely Cause for Population Declines of Alpine Frogs in the Sierra Nevada, California

    Science.gov (United States)

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured...

  18. 77 FR 23476 - Energia Sierra Juarez U.S., LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2012-04-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Energia Sierra Juarez U.S., LLC; Supplemental Notice That Initial Market... in the above-referenced proceeding of Energia Sierra Juarez U.S., LLC's application for...

  19. 78 FR 72926 - Bald and Golden Eagles; Migratory Birds; Phase I Development of the Chokecherry-Sierra Madre Wind...

    Science.gov (United States)

    2013-12-04

    ...), announce our intent to prepare a draft Environmental Impact Statement (EIS) for Phase I of the Chokecherry-Sierra Madre Wind Energy Project. Our draft EIS will analyze the environmental impacts associated with... Chokecherry-Sierra Madre Wind Energy Project AGENCY: Fish and Wildlife Service, Interior. ACTION: Notice...

  20. Airborne Pesticides as an Unlikely Cause for Population Declines of Alpine Frogs in the Sierra Nevada, California

    Science.gov (United States)

    Airborne pesticides from the Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the mountain yellow-legged frog complex (Rana muscosa and R. sierrae) in the Sierra Nevada. We measured...

  1. Relación de la inestabilidad estructural con el manejo y propiedades de los suelos de la región pampeana Relation of structural instability with management and properties of soils in the Pampean region

    Directory of Open Access Journals (Sweden)

    Carina Rosa Álvarez

    2012-12-01

    Full Text Available La inestabilidad estructural (IEST permite caracterizar la resistencia a la degradación de los suelos. Se determinó la IEST (De Leenheer& De Boodt en 67 sitios de muestreo bajo distintos manejos en la Región Pampeana norte, con el objetivo de comparar los manejos y analizar su relación con: a la densidad aparente (DAP; b el contenido de carbono orgánico total y sus fracciones particulada (> 53 mm y resistente (Soil structural instability (IEST characterizes the resistance to degradation of soils. Soil IEST (De Leenheer and De Boodt was determined in 67 sites under different soil managements in the Northern Pampean Region, in order to establish its relation with: a core bulk density (DAP; b total organic carbon and its particulate (> 53 mm and resistant (<53 mm fractions; c granulometric fractions; and d relative compaction (ratio bulk density to maximum bulk density by Proctor Test. Soil IEST allowed distinguishing among quasi-pristine and agriculture under tillage (P<0.05. Meanwhile integrated crop-livestock systems under no tillage and agriculture under no tillage presented intermediate values. DAP was highest in the integrated crop-livestock systems under no tillage. A multiple regression model (R2 = 0.37 was fitted between IEST and total organic carbon and silt content and a Dummy variable related to management. DAP was negatively related with total organic carbon and clay content and positive with a Dummy variable (value= 1 for integrated crop-livestock systems and 0 for the others (R2= 0.62. Results suggest other stabilizing agents like the action of plant roots could be responsible for the variation in SI in these soils. It can be concluded that higher carbon contents are required to stabilize silty soils.

  2. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierrae from California

    Science.gov (United States)

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour. Copyright ?? 2011 British Lichen Society.

  3. Copper localization, elemental content, and thallus colour in the copper hyperaccumulator lichen Lecanora sierra from California

    Science.gov (United States)

    Purvis, O.W.; Bennett, J.P.; Spratt, J.

    2011-01-01

    An unusual dark blue-green lichen, Lecanora sierrae, was discovered over 30 years ago by Czehura near copper mines in the Lights Creek District, Plumas County, Northern California. Using atomic absorption spectroscopy, Czehura found that dark green lichen samples from Warren Canyon contained 4% Cu in ash and suggested that its colour was due to copper accumulation in the cortex. The present study addressed the hypothesis that the green colour in similar material we sampled from Warren Canyon in 2008, is caused by copper localization in the thallus. Optical microscopy and electron microprobe analysis of specimens of L. sierrae confirmed that copper localization took place in the cortex. Elemental analyses of L. sierrae and three other species from the same localities showed high enrichments of copper and selenium, suggesting that copper selenates or selenites might occur in these lichens and be responsible for the unusual colour.

  4. Structure of Sierra Madera, Texas, as a guide to central peaks of lunar craters.

    Science.gov (United States)

    Howard, K. A.; Wilshire, H. G.; Offield, T. W.

    1972-01-01

    The central peaks of Copernicus or a similar lunar crater have been considered as a target for manned exploration, partly on the supposition that the peaks expose rock uplifted from beneath the crater floor. This supposition is based on an analogy with central uplifts of terrestrial cryptoexplosion structures. Sierra Madera in west Texas is one of these structures. The structure of its central uplift is described as a proposed analog of the central peaks of large lunar impact craters. Setting and stratigraphy of the Sierra Madera are discussed together with structural framework, the central uplift, fold patterns, and fault patterns. It is concluded that the central uplifts of Sierra Madera and similar cryptoexplosion structures appear to be analogous to central peaks of large lunar impact craters.

  5. Dataset of Passerine bird communities in a Mediterranean high mountain (Sierra Nevada, Spain)

    Science.gov (United States)

    Pérez-Luque, Antonio Jesús; Barea-Azcón, José Miguel; Álvarez-Ruiz, Lola; Bonet-García, Francisco Javier; Zamora, Regino

    2016-01-01

    Abstract In this data paper, a dataset of passerine bird communities is described in Sierra Nevada, a Mediterranean high mountain located in southern Spain. The dataset includes occurrence data from bird surveys conducted in four representative ecosystem types of Sierra Nevada from 2008 to 2015. For each visit, bird species numbers as well as distance to the transect line were recorded. A total of 27847 occurrence records were compiled with accompanying measurements on distance to the transect and animal counts. All records are of species in the order Passeriformes. Records of 16 different families and 44 genera were collected. Some of the taxa in the dataset are included in the European Red List. This dataset belongs to the Sierra Nevada Global-Change Observatory (OBSNEV), a long-term research project designed to compile socio-ecological information on the major ecosystem types in order to identify the impacts of global change in this area. PMID:26865820

  6. Multiple circulating infections can mimic the early stages of viral hemorrhagic fevers and possible human exposure to filoviruses in Sierra Leone prior to the 2014 outbreak.

    Science.gov (United States)

    Boisen, Matthew L; Schieffelin, John S; Goba, Augustine; Oottamasathien, Darin; Jones, Abigail B; Shaffer, Jeffrey G; Hastie, Kathryn M; Hartnett, Jessica N; Momoh, Mambu; Fullah, Mohammed; Gabiki, Michael; Safa, Sidiki; Zandonatti, Michelle; Fusco, Marnie; Bornholdt, Zach; Abelson, Dafna; Gire, Stephen K; Andersen, Kristian G; Tariyal, Ridhi; Stremlau, Mathew; Cross, Robert W; Geisbert, Joan B; Pitts, Kelly R; Geisbert, Thomas W; Kulakoski, Peter; Wilson, Russell B; Henderson, Lee; Sabeti, Pardis C; Grant, Donald S; Garry, Robert F; Saphire, Erica O; Branco, Luis M; Khan, Sheik Humarr

    2015-02-01

    Lassa fever (LF) is a severe viral hemorrhagic fever caused by Lassa virus (LASV). The LF program at the Kenema Government Hospital (KGH) in Eastern Sierra Leone currently provides diagnostic services and clinical care for more than 500 suspected LF cases per year. Nearly two-thirds of suspected LF patients presenting to the LF Ward test negative for either LASV antigen or anti-LASV immunoglobulin M (IgM), and therefore are considered to have a non-Lassa febrile illness (NLFI). The NLFI patients in this study were generally severely ill, which accounts for their high case fatality rate of 36%. The current studies were aimed at determining possible causes of severe febrile illnesses in non-LF cases presenting to the KGH, including possible involvement of filoviruses. A seroprevalence survey employing commercial enzyme-linked immunosorbent assay tests revealed significant IgM and IgG reactivity against dengue virus, chikungunya virus, West Nile virus (WNV), Leptospira, and typhus. A polymerase chain reaction-based survey using sera from subjects with acute LF, evidence of prior LASV exposure, or NLFI revealed widespread infection with Plasmodium falciparum malaria in febrile patients. WNV RNA was detected in a subset of patients, and a 419 nt amplicon specific to filoviral L segment RNA was detected at low levels in a single patient. However, 22% of the patients presenting at the KGH between 2011 and 2014 who were included in this survey registered anti-Ebola virus (EBOV) IgG or IgM, suggesting prior exposure to this agent. The 2014 Ebola virus disease (EVD) outbreak is already the deadliest and most widely dispersed outbreak of its kind on record. Serological evidence reported here for possible human exposure to filoviruses in Sierra Leone prior to the current EVD outbreak supports genetic analysis that EBOV may have been present in West Africa for some time prior to the 2014 outbreak.

  7. Dominant Factors Controlling the Hydrometeorology of Northern California: Landfalling Atmospheric Rivers and Sierra Barrier Jets

    Science.gov (United States)

    Neiman, P. J.; Ralph, F. M.; Hughes, M.; Sukovich, E.; Kingsmill, D. E.; Zamora, R. J.; Moore, B. J.

    2014-12-01

    Northern California's Sierra Nevada and Shasta-Trinity mountains are key to the state's water supply and can contribute to major floods in the Central Valley (CV). NOAA's Hydrometeorology Testbed (HMT) program and the CalWater experiment have discovered much about how landfalling atmospheric rivers (AR) and Sierra Barrier Jets (SBJ) modulate orographic precipitation in that region. This presentation provides a review of recent findings, both from case-study and compositing perspectives. Wind-profiler and global-positioning-system (GPS) observations are used with soil moisture probes, stream gauges, and a regional reanalysis dataset. Key results include: Inland-directed ARs override a ~1-km-deep, Sierra-parallel SBJ located above the CV and the western slope of the Sierra. Above the developing SBJ, strengthening southwesterly flow marks the AR. The moistening SBJ reaches maximum intensity during the strongest AR flow aloft, at which time the core of the AR-parallel vapor transport slopes over the SBJ and intersects the Sierra. The SBJ then weakens with the initial cold-frontal passage aloft. A statistical analysis of orographic forcing reveals that both the AR and SBJ are crucial in determining the distribution of precipitation in the northern Sierra and Shasta-Trinity regions due to orographic precipitation enhancement. An open question remains regarding the transport of water vapor near the northern end of the CV. Namely, a portion of the AR-modulated SBJ flow may be transported through a prominent gap in the terrain between Mt. Lassen and Mt. Shasta, near the town of Burney. Recent analyses indicate that this gap allows AR water vapor to penetrate into the western interior (e.g., to Idaho) and thus contribute to heavy precipitation events far inland. The CalWater-2 program of field campaigns has identified diagnosis of the transport through this gap and its impact on northern California precipitation as a priority for future data collection and analysis.

  8. Paleotsunamis in Eastern Taiwan

    Science.gov (United States)

    Yen, Jiun-Yee; Yu, Neng-Ti; Hirakawa, Kazuomi; Chyi, Shyh-Jeng; Huang, Shao-Yi

    2017-04-01

    Although Taiwan is located in the active collision zone between Eurasian and the Philippine Sea plate with very high seismicity in and surrounding the island, and supposedly highly susceptible to tsunami hazard. However, there is no record of tsunami hazard in the past one hundred years, and only very few historical records show some possible extreme event occurred. Therefore study of tsunami was scarce in Taiwan. Although historical records do show possible tsunami events, the records were too sparse and incomplete to confidently reconstruct the paleotsunami events. In the past few years, numerical simulations based on possible tsunami-genic zones near Taiwan show that the island could be affected by the correctly directed tsunami. Nevertheless, there is no detail, scientific research of paleotsunami records yet in Taiwan. Our field survey in eastern Taiwan (facing the western Pacific Ocean) along the coast uncovered several outcrops contain gravels embedded in well-developed soil layers. The rounded meta-sandstone gravels are clearly beach-origin and were brought to their current location upon extreme wave events, which is composed of either volcanic-clastic deposits from nearby hills or organic soil layers formed locally. Our investigation indicates that there are at least 3 events in the northern half of eastern Taiwan and at least 2 events in southern part of eastern Taiwan. Although these outcrops are next to the shoreline and Taiwan is susceptible from typhoons, these gravels could be farther away from the beach at the time of their deposition due to current high retreat rate of the sea cliff. Further investigations are needed to delineate possible sources of tsunamis that caused the deposits.

  9. Origen y decadencia del gamonalismo en la sierra ecuatoriana

    Directory of Open Access Journals (Sweden)

    Ibarra Crespo, Hernán

    2002-12-01

    Full Text Available This article analyzes the historical path of gamonalismo in Ecuadorian highlands. Although it could be alike to Mexican caciquismo and Brazilian coronelismo, gamonalismo had its specific forms. In Ecuador it is possible to reconstruct its meaning in political terms, as a form of traditional domination. The use of this particular term is analyzed in different historical moments between the 18th and 20th century; focusing on the origin and decline of this local power. The aim is to build an interpretative frame in order to understand agrarian sources of Ecuadorian state development and ethnic domination.

    Este artículo analiza la trayectoria histórica del gamonalismo en la sierra ecuatoriana. Aunque homologado con el caciquismo mexicano y el coronelismo brasileño, tiene rasgos específicos. En el Ecuador es posible reconstruir el significado del gamonalismo en el lenguaje político y como modalidad de dominación tradicional. Por una parte, se realiza un rastreo y análisis del uso del término en distintos momentos históricos entre los siglos XVIII y XX. Por otra parte, se efectúa un abordaje del origen y declinación de esta forma de poder. Se aspira a construir un marco interpretativo que aporte a la comprensión de los fundamentos agrarios de la constitución del Estado ecuatoriano y las formas de dominación étnica.

  10. Overcoming Operational Challenges to Ebola Case Investigation in Sierra Leone.

    Science.gov (United States)

    T Boland, Samuel; Polich, Erin; Connolly, Allison; Hoar, Adam; Sesay, Tom; Tran, Anh-Minh A

    2017-09-27

    The Ebola virus disease (EVD) epidemic that hit West Africa in 2013 was the worst outbreak of EVD in recorded history. While much has been published regarding the international and national-level EVD responses, there is a dearth of literature on district-level coordination and operational structures, successes, and failures. This article seeks to understand how the EVD response unfolded at the district level, namely the challenges to operationalizing EVD surveillance over the course of the outbreak in Port Loko and Kambia districts of Sierra Leone. We present here GOAL Global's understanding of the fundamental challenges to case investigation operations during the EVD response, including environmental and infrastructural, sociocultural, and political and organizational challenges, with insight complemented by a survey of 42 case investigators. Major challenges included deficiencies in transportation and communication resources, low morale and fatigue among case investigators, mismanagement of data, mistrust among communities, and leadership challenges. Without addressing these operational challenges, technical surveillance solutions are difficult to implement and hold limited relevance, due to the poor quality and quantity of data being collected. The low prioritization of operational needs came at a high cost. To mediate this, GOAL addressed these operational challenges by acquiring critical transportation and communication resources to facilitate case investigation, including vehicles, boats, fuel, drivers, phones, and closed user groups; addressing fatigue and low morale by hiring more case investigators, making timely payments, arranging for time off, and providing meals and personal protective equipment; improving data tracking efforts through standard operating procedures, training, and mentorship to build higher-quality case histories and make it easier to access information; strengthening trust in communities by ensuring familiarity and consistency of case

  11. Espacio urbano, espacio del consumo en las crónicas norteamericanas de Justo Sierra

    OpenAIRE

    Cristina Beatriz Fernández

    2011-01-01

    El objetivo de este trabajo es analizar las crónicas de viaje de Justo Sierra, escritas en ocasión de su visita a los Estados Unidos a finales del siglo XIX, con énfasis en las dedicadas a la ciudad de Nueva York. En ellas, centramos nuestra atención en el registro textual de fenómenos relacionados con la forma en que Sierra percibe la modernidad norteamericana, especialmente significativa en lo que hace a la relación entre economía y sociedad. Por ello, atendemos particularmente la configura...

  12. "Caliban," a poem by Syl Cheney-Coker or Caliban in Sierra Leone 

    OpenAIRE

    Fioupou, Christiane

    2015-01-01

    Une traduction française du poème "Caliban," du romancier et poète sierra-léonais Syl Cheney-Coker, est proposée ici à la suite du texte original ; le poème est précédé d’une courte présentation qui introduit les commentaires du poète sur "son Caliban" et la société krio de Sierra Leone.

  13. SIERRA Code Coupling Module: Arpeggio User Manual Version 4.44

    Energy Technology Data Exchange (ETDEWEB)

    Sierra Thermal/Fluid Team

    2017-04-01

    The SNL Sierra Mechanics code suite is designed to enable simulation of complex multiphysics scenarios. The code suite is composed of several specialized applications which can operate either in standalone mode or coupled with each other. Arpeggio is a supported utility that enables loose coupling of the various Sierra Mechanics applications by providing access to Framework services that facilitate the coupling. More importantly Arpeggio orchestrates the execution of applications that participate in the coupling. This document describes the various components of Arpeggio and their operability. The intent of the document is to provide a fast path for analysts interested in coupled applications via simple examples of its usage.

  14. Gravity data from the Sierra Vista Subwatershed, Upper San Pedro Basin, Arizona

    Science.gov (United States)

    Kennedy, Jeffrey R.

    2015-01-01

    Observations of very small changes of Earth’s gravitational field (time-lapse gravity) provide a direct, non-invasive method for measuring changes in aquifer storage change. An existing network of gravity stations in the Sierra Vista Subwatershed was revised in 2014 to better understand the spatial distribution of changes in aquifer storage, especially with relation to ephemeral channel recharge and a groundwater cone of depression associated with pumping in the greater Sierra Vista area. In addition, the network was extended to provide baseline data for possible future enhanced-recharge projects.

  15. Vencer la derrota. Vivir en la Sierra Zapoteca de México (1674-1707)

    OpenAIRE

    Béligand, Nadine

    2015-01-01

    Una fotografía nos permite sumergirnos en esta historia de derrota. Posado en las cimas de la sierra, un aura escruta el horizonte del Valle de las Nubes, telón de fondo de la historia de Los tres mosqueteros de Yasona; aguarda a que la historia le sea revelada. Este libro, que nace del encuentro de un historiador con los archivos judiciales de Oaxaca, es una verdadera lección de historia sobre el poder en un pueblo de la Sierra Zapoteca. Thomas Calvo rompe con la linealidad del relato cronol...

  16. Ecofeminismo, mujeres y desarrollo sustentable: el caso de la Sierra de Santa Rosa en Guanajuato

    OpenAIRE

    Abril Saldaña Tejeda

    2015-01-01

    en este artículo se explora la participación de las mujeres en el Programa de Desarrollo Sustentable Sierra de Santa Rosa, en Guanajuato, de 2001 a 2011. Se expone la aportación del ecofeminismo para la noción de desarrollo sustentable, y para entender el vínculo entre la naturaleza y las mujeres. Se argumenta que la historia de la región, en específico el auge de la industria minera durante la Colonia, es un buen punto de partida para entender los problemas ambientales de la sierra y para vi...

  17. Numerical Wind Modeling for the San Pedro Mártir Sierra in Baja California

    Directory of Open Access Journals (Sweden)

    K. Vogiatzis

    2004-01-01

    Full Text Available Presentamos la simulación numérica del viento en la Sierra de San Pedro Mártir para realizar una evaluación preliminar de los posibles sitios donde instalar nuevos telescopios. Como criterio inicial, se eligieron los puntos más altos de la sierra, pero a la vez de fácil acceso. Se presentan la altura de la capa límite y el efecto de la turbulencia en los diferentes sitios para velocidades y direcciones del viento típicas.

  18. Status and understanding of groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units, 2006-2007--California GAMA Priority Basin Project

    Science.gov (United States)

    Fram, Miranda S.; Belitz, Kenneth

    2012-01-01

    Groundwater quality in the Tahoe-Martis, Central Sierra, and Southern Sierra study units was investigated as part of the Priority Basin Project of the California Groundwater Ambient Monitoring and Assessment (GAMA) Program. The three study units are located in the Sierra Nevada region of California in parts of Nevada, Placer, El Dorado, Madera, Tulare, and Kern Counties. The GAMA Priority Basin Project is being conducted by the California State Water Resources Control Board, in collaboration with the U.S. Geological Survey (USGS) and the Lawrence Livermore National Laboratory. The project was designed to provide statistically robust assessments of untreated groundwater quality within the primary aquifer systems used for drinking water. The primary aquifer systems (hereinafter, primary aquifers) for each study unit are defined by the depth of the screened or open intervals of the wells listed in the California Department of Public Health (CDPH) database of wells used for municipal and community drinking-water supply. The quality of groundwater in shallower or deeper water-bearing zones may differ from that in the primary aquifers; shallower groundwater may be more vulnerable to contamination from the surface. The assessments for the Tahoe-Martis, Central Sierra, and Southern Sierra study units were based on water-quality and ancillary data collected by the USGS from 132 wells in the three study units during 2006 and 2007 and water-quality data reported in the CDPH database. Two types of assessments were made: (1) status, assessment of the current quality of the groundwater resource, and (2) understanding, identification of the natural and human factors affecting groundwater quality. The assessments characterize untreated groundwater quality, not the quality of treated drinking water delivered to consumers by water purveyors. Relative-concentrations (sample concentrations divided by benchmark concentrations) were used for evaluating groundwater quality for those

  19. Shortening in the Central Andes at the transition to flat slab subduction

    Science.gov (United States)

    Safipour, R.; DeCelles, P. G.; Carrapa, B.; Kapp, P. A.; Gehrels, G. E.; Reiners, P. W.

    2011-12-01

    Shortening in the Central Andes is considered to decrease north and south of the apex of the Bolivian orocline, mainly owing to differences in the pre-existing stratigraphic architecture of the continental margin. Estimates of shortening in the central Andes of northern Argentina remain poorly documented, but are required for assessment of the regional kinematic history of the orogenic system. The problem is acute at the north to south transition from the high elevation Puna plateau to the lower elevation region of the Sierras Pampeanas intra-foreland block uplifts, which corresponds with a transition to a flat segment of the subducting Nazca plate. Although deformation in the Eastern Cordillera appears to have propagated forelandward from west to east, the trend in the Sierras Pampeanas is not clear from existing data. We mapped the structures along a roughly E-W transect at latitude 28°S in the Sierra de Las Planchadas of the northern Sierras Pampeanas to measure finite strain and kinematic indicators, and to develop a regional restorable cross section for measuring total shortening. We also sampled for low-T thermochronology in order to determine the timing of exhumation and inferred thrust propagation. A minimum of 40 km of shortening in the Sierra de Las Planchadas is estimated from our restored cross section. When added to the 20 km shortening documented in ranges to the east by previous studies, this brings the total minimum estimated shortening at this latitude to ~60 km. Apatite fission track ages from the hanging walls of thrusts are ~20 Ma, and apatite helium ages range from 10 Ma west of the range to 2.3 Ma in the Fiambalá basin which borders the range to the east. Cretaceous and Paleogene cooling ages are observed in ranges to the east of the Sierra de Las Planchadas, so the young cooling ages found in this study suggest that exhumation was complex and possibly diachronous at this latitude. To the extent that exhumation occurs simultaneously with

  20. Noteworthy records of two species of mammals in the Sierra Madre de Oaxaca, Mexico Registros notables de dos especies de mamíferos de la Sierra Madre de Oaxaca, México

    Directory of Open Access Journals (Sweden)

    Miguel Briones-Salas

    2006-12-01

    Full Text Available We conducted mammal surveys in the Sierra Madre de Oaxaca (Sierra Norte in Oaxaca, Mexico, and recorded the occurrence of two conspicuous mammal species: the spider monkey (Ateles geoffroyi vellerosus and the coyote (Canis latrans cagottis. Spider monkeys has not been previously recorded in the Sierra Madre de Oaxaca, and coyotes have not been previously observed in Mexico at elevations as high as the present one (3 200 mas1 in the Sierra Madre de Oaxaca.Se efectuaron colectas de mamíferos en la Sierra Madre de Oaxaca (Sierra Norte en Oaxaca, México, y se registró la notoria presencia de dos mamíferos: el mono araña (Ateles geoffroyi vellerosus y el coyote (Canis latrans cagottis. El mono araña no se había registrado previamente en la Sierra Madre de Oaxaca, en tanto que el coyote, no había sido registrado en México a tan gran altitud (3 200 m como la de la localidad de captura.

  1. Macroindicadores cinemáticos en el Bloque Ambato, provincias de Tucumán y Catamarca Kinematic macroindicators in the Ambato Block, provinces of Tucumán and Catamarca

    Directory of Open Access Journals (Sweden)

    Adolfo Antonio Gutiérrez

    2008-03-01

    Full Text Available En el extremo oriental del antepaís andino (65°30'-66°15'O y 27°30'-28°30'S un conjunto de sierras (bloque Ambato se orientan en dirección noroeste evidenciando un desplazamiento hacia el este de aproximadamente 26,5 km que contrastan con la tendencia regional noreste de las sierras de Aconquija al norte y Ancasti al sur. Estas sierras pertenecen al sistema morfotectónico de Sierras Pampeanas. El conjunto de sierras que constituyen el bloque Ambato deben su morfoestructura actual a cizallamiento sinistral de rumbo noroeste que produjo procesos tectónicos extensivos y transpresivos en el Pleistoceno. Macroindicadores cinemáticos dan cuenta de estos procesos: fallas normales, cuencas intramontanas y valles, cuñas de deformación, fallas rotacionales, fallas inversas, cizallas Riedel y estructuras elípticas.At the eastern-most Andean foreland (65°30'-66°15'W y 27°30'-28°30'S the Ambato Block mountain shows a NW orientation which differs from the common NE regional strike, at this part of the Pampean Ranges. The present-day morphotectonics configuration of the Ambato Block is due to a Pleistocene synistral shear zone along the major north/south Andean faults. Kinematic macroindicators identified are: second order Riedel fractures, transpressive structure like deformation wedges and pull-apart basins, rotational faults, normal faults, inverse faults and eliptic structures.

  2. Population dynamics of the California spotted owl in the Sierra Nevada, California

    Science.gov (United States)

    J.A. Blakesley; M.E. Seamans; M.M. Connor; A.B. Franklin; G.C. White; R.J. Gutierrez; J.E. Hines; J.D. Nichols; T.E. Munton; D.W.H. Shaw; J.J. Keane; G.N. Steger; T.L. McDonald

    2010-01-01

    The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California,...

  3. Telegrama de Justo Sierra a Miguel de Unamuno. [S.l.], 1910?

    OpenAIRE

    Sierra, Justo, 1848-1912

    2009-01-01

    Telegrama del escritor, abogado y profesor mexicano Justo Sierra, secretario de Información Pública y Bellas Artes, a Miguel de Unamuno informándole que las universidades de Salamanca, París y California apadrinarán la inauguración de la Universidad Nacional Autónoma de México.

  4. Potential increase in floods in California's Sierra Nevada under future climate projections

    Science.gov (United States)

    Das, T.; Dettinger, M.D.; Cayan, D.R.; Hidalgo, H.G.

    2011-01-01

    California's mountainous topography, exposure to occasional heavily moisture-laden storm systems, and varied communities and infrastructures in low lying areas make it highly vulnerable to floods. An important question facing the state-in terms of protecting the public and formulating water management responses to climate change-is "how might future climate changes affect flood characteristics in California?" To help address this, we simulate floods on the western slopes of the Sierra Nevada Mountains, the state's primary catchment, based on downscaled daily precipitation and temperature projections from three General Circulation Models (GCMs). These climate projections are fed into the Variable Infiltration Capacity (VIC) hydrologic model, and the VIC-simulated streamflows and hydrologic conditions, from historical and from projected climate change runs, allow us to evaluate possible changes in annual maximum 3-day flood magnitudes and frequencies of floods. By the end of the 21st Century, all projections yield larger-than-historical floods, for both the Northern Sierra Nevada (NSN) and for the Southern Sierra Nevada (SSN). The increases in flood magnitude are statistically significant (at p rain and less as snow. Increases in antecedent winter soil moisture also play a role in some areas. Thus, a complex, as-yet unpredictable interplay of several different climatic influences threatens to cause increased flood hazards in California's complex western Sierra landscapes. ?? 2011 Springer Science+Business Media B.V.

  5. Empowering Women through Education: Evidence from Sierra Leone. NBER Working Paper No. 18016

    Science.gov (United States)

    Mocan, Naci H.; Cannonier, Colin

    2012-01-01

    We use data from Sierra Leone where a substantial education program provided increased access to education for primary-school age children but did not benefit children who were older. We exploit the variation in access to the program generated by date of birth and the variation in resources between various districts of the country. We find that…

  6. Sierra Leone's Former Child Soldiers: A Follow-Up Study of Psychosocial Adjustment and Community Reintegration

    Science.gov (United States)

    Betancourt, Theresa Stichick; Borisova, Ivelina Ivanova; Williams, Timothy Philip; Brennan, Robert T.; Whitfield, Theodore H.; de la Soudiere, Marie; Williamson, John; Gilman, Stephen E.

    2010-01-01

    This is the first prospective study to investigate psychosocial adjustment in male and female former child soldiers (ages 10-18; n = 156, 12% female). The study began in Sierra Leone in 2002 and was designed to examine both risk and protective factors in psychosocial adjustment. Over the 2-year period of follow-up, youth who had wounded or killed…

  7. "Farming Miners" or "Mining Farmers"?: Diamond Mining and Rural Development in Post-Conflict Sierra Leone

    Science.gov (United States)

    Maconachie, Roy; Binns, Tony

    2007-01-01

    Sierra Leone is currently emerging from a brutal civil war that lasted most of the 1990s, and now has the dubious distinction of being ranked among the world's poorest countries. As thousands of displaced people move back to their villages, a large proportion of the predominantly farm-based rural population are growing food crops for the first…

  8. Training for Innovation: Capacity-Building in Agricultural Research in Post-War Sierra Leone

    Science.gov (United States)

    Gboku, Matthew L. S.; Bebeley, Jenneh F.

    2016-01-01

    This paper examines how the Sierra Leone Agricultural Research Institute (SLARI) used training and development to build capacity for innovation in agricultural research following the country's civil war which ended in 2002. The Institute's training for innovation addressed different agricultural product value chains (APVCs) within the framework of…

  9. Reconstruction versus Transformation: Post-War Education and the Struggle for Gender Equity in Sierra Leone

    Science.gov (United States)

    Maclure, Richard; Denov, Myriam

    2009-01-01

    In post-war contexts, education is widely regarded as essential not only for civic reconciliation, but also as a key force for gender equity. In Sierra Leone, however, despite enhanced educational opportunities for girls, much of the emphasis on post-war educational reconstruction is unlikely to rectify gender inequities that remain entrenched…

  10. PARTITIONING OF WATER FLUX IN A SIERRA NEVADA PONDEROSA PINE PLANTATION. (R826601)

    Science.gov (United States)

    The weather patterns of the west side of the Sierra Nevada Mountains (cold, wet winters and hot, dry summers) strongly influence how water is partitioned between transpiration and evaporation and result in a specific strategy of water use by ponderosa pine trees (Pinus pond...

  11. Pesticide Distributions and Population Declines of California Alpine Frogs, Rana Muscosa and Rana Sierrae

    Science.gov (United States)

    Atmospherically deposited pesticides from the intensively cultivated Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the frogs Rana muscosa and Rana sierrae at high elevation in th...

  12. Genotypic anomaly in ebola virus strains circulating in magazine wharf Area, Freetown, Sierra Leone, 2015

    NARCIS (Netherlands)

    S.L. Smits (Saskia); S.D. Pas (Suzan); C.B.E.M. Reusken (Chantal); B.L. Haagmans (Bart); P. Pertile; C. Cancedda; K. Dierberg; I. Wurie; A. Kamara; D. Kargbo; S.L. Caddy; A. Arias; L. Thorne; J. Lu; U. Jah; I. Goodfellow; M.P.G. Koopmans D.V.M. (Marion)

    2015-01-01

    textabstractThe Magazine Wharf area, Freetown, Sierra Leone was a focus of ongoing Ebola virus transmission from late June 2015. Viral genomes linked to this area contain a series of 13 T to C substitutions in a 150 base pair intergenic region downstream of viral protein 40 open reading frame, simil

  13. Coming back from the bush : gender, youth and reintegration in northern Sierra Leone

    NARCIS (Netherlands)

    Gog, van J.G.

    2008-01-01

    This thesis explores the postwar reintegration strategies of young women who had forcibly become affiliated with one of the fighting factions during the ten years of civil war in Sierra Leone. Instead of conceptualizing reintegration as the result of policies, the author defines it as the dynamic pr

  14. School Persistence in the Wake of War: Wartime Experiences, Reintegration Supports, and Dropout in Sierra Leone

    Science.gov (United States)

    Zuilkowski, Stephanie Simmons; Betancourt, Theresa S.

    2014-01-01

    This article examines the relationship of wartime experience and reintegration supports to students' risk of school dropout. It draws on longitudinal, mixed-methods data collected among children and youth in Sierra Leone from 2002 through 2008. The study finds that family financial support and perceived social support are positively associated…

  15. Sierra Leone's Former Child Soldiers: A Longitudinal Study of Risk, Protective Factors, and Mental Health

    Science.gov (United States)

    Betancourt, Theresa S.; Brennan, Robert T.; Rubin-Smith, Julia; Fitzmaurice, Garrett M.; Gilman, Stephen E.

    2010-01-01

    Objective: To investigate the longitudinal course of internalizing and externalizing problems and adaptive/prosocial behaviors among Sierra Leonean former child soldiers and whether postconflict factors contribute to adverse or resilient mental health outcomes. Method: Male and female former child soldiers (N = 260, aged 10 to 17 years at…

  16. Illiteracy, Colonial Legacy and Education: The Case of Modern Sierra Leone.

    Science.gov (United States)

    Banya, Kingsley

    1993-01-01

    As a legacy of British colonial rule, Sierra Leone's education system gives half of its budget to higher education, heavily benefits the upper and middle classes and serves the poor and rural populations badly. The illiteracy rate is 85%. Policy recommendations are outlined for resource allocation and major restructuring of the education system.…

  17. Hacia una Estrategia de Desarrollo para la Sierra Rural en el Perú

    NARCIS (Netherlands)

    Escobal, J.A.; Valdivia, L.

    2004-01-01

    El objetivo de este proyecto es elaborar un documento que establezca los lineamientos de una política de desarrollo para la Sierra rural en el Perú e identificar los requerimientos institucionales y de investigación complementaria que se requerirían para la construcción de programas específicos que

  18. Early Phanerozoic trace fossils from the Sierra Albarrana quartzites (Ossa-Morena Zone, Southwest Spain)

    NARCIS (Netherlands)

    Marcos, A.; Azor, A.; González, F.; Simancas, F.

    1991-01-01

    Three ichnogenera are described from a 50 to 500 m thick shallow-water sandstone-shale sequence (Sierra Albarrana Quartzites). The ichnofauna consists of the burrows of worm-like animals (Arenicolites, Monocraterion, and Skolithos). The age of this formation, previously considered to be Precambrian

  19. Socio-Ecological Factors Affecting Pregnant Women's Anemia Status in Freetown, Sierra Leone

    Science.gov (United States)

    M'Cormack, Fredanna; Drolet, Judy

    2012-01-01

    Background: Sierra Leone has high maternal mortality. Socio-ecological factors are considered contributing factors to this high mortality. Anemia is considered to be a direct cause of 4% of maternal deaths and an indirect cause of 20-40% of maternal deaths. Purpose: The current study explores socio-ecological contributing factors to the anemia…

  20. Eocene activity on the Western Sierra Fault System and its role incising Kings Canyon, California

    Science.gov (United States)

    Sousa, Francis J.; Farley, Kenneth A.; Saleeby, Jason; Clark, Marin

    2016-04-01

    Combining new and published apatite (U-Th)/He and apatite 4He/3He data from along the Kings River canyon, California we rediscover a west-down normal fault on the western slope of the southern Sierra Nevada, one of a series of scarps initially described by Hake (1928) which we call the Western Sierra Fault System. Integrating field observations with apatite (U-Th)/He data, we infer a single fault trace 30 km long, and constrain the vertical offset across this fault to be roughly a kilometer. Thermal modeling of apatite 4He/3He data documents a pulse of footwall cooling near the fault and upstream in the footwall at circa 45-40 Ma, which we infer to be the timing of a kilometer-scale incision pulse resulting from the fault activity. In the context of published data from the subsurface of the Sacramento and San Joaquin Valleys, our data from the Western Sierra Fault System suggests an Eocene tectonic regime dominated by low-to-moderate magnitude extension, surface uplift, and internal structural deformation of the southern Sierra Nevada and proximal Great Valley forearc.

  1. Child mental health in Sierra Leone : A survey and exploratory qualitative study

    NARCIS (Netherlands)

    Yoder, H.N.C.; Tol, W.A.; Reis, R.; de Jong, J.T.V.M.

    2016-01-01

    Background This study complements the growing amount of research on the psychosocial impact of war on children in Sierra Leone by examining local perceptions of child mental health, formal and informal care systems, help-seeking behaviour and stigma. Methods The study combined: (1) a nationwide

  2. Who cares for former child soldiers? Mental health systems of care in Sierra Leone

    NARCIS (Netherlands)

    Song, S.; van den Brink, H.; de Jong, J.

    2013-01-01

    While numerous studies on former child soldiers (FCS) have shown mental health needs, adequate services are a challenge. This study aimed to identify priorities, barriers and facilitators of mental health care for Sierra Leonean FCS. Thematic analysis was done on 24 qualitative interviews with parti

  3. Bodies in action. Culture and body skills in post-conflict Sierra Leone

    NARCIS (Netherlands)

    Niet, van der A.

    2010-01-01

    This book is about human body movement and culture. The body skills of a sample of Sierra Leoneans are analyzed in terms of acquisition of the skills, the importance of learning these skills to become part of a community and the physical consequences of the activities. It focuses on skills in footba

  4. A study of nivicolous Myxomycetes in southern Europe, Sierra de Guadarrama, Spain

    NARCIS (Netherlands)

    Sánchez, A.; Moreno, G.; Illana, C.; Singer, H.

    2002-01-01

    Eleven taxa of Myxomycetes collected from around melting snow banks in mountainous and alpine areas of the Sierra de Guadarrama (Madrid, Segovia) are presented. From a chronological point of view several new records for the Iberian Peninsula are interesting: Lepidoderma carestianum, Lepidoderma gran

  5. Mercury in Tadpoles Collected from Remote Alpine Sites in the Southern Sierra Nevada Mountains, California, USA

    Science.gov (United States)

    Amphibians in alpine wetlands of the Sierra Nevada mountains comprise key components of an aquatic-terrestrial food chain, and mercury contamination is a concern because concentrations in fish from this regin exceed thresholds of risk to piscivorous wildlife. Total mercury conc...

  6. Socio-Ecological Factors Affecting Pregnant Women's Anemia Status in Freetown, Sierra Leone

    Science.gov (United States)

    M'Cormack, Fredanna; Drolet, Judy

    2012-01-01

    Background: Sierra Leone has high maternal mortality. Socio-ecological factors are considered contributing factors to this high mortality. Anemia is considered to be a direct cause of 4% of maternal deaths and an indirect cause of 20-40% of maternal deaths. Purpose: The current study explores socio-ecological contributing factors to the anemia…

  7. Palaeomagnetic results from the southern Sierra Madre Oriental, Mexico: evidence for Early Cretaceous or Laramide remagnetization?

    Science.gov (United States)

    Böhnel, H.; Gose, W. A.; Testarmata, M. M.; Bocanegra Noriega, G.

    1990-12-01

    A large suite of samples from the Latest Triassic Huizachal and Early Jurassic Huayacocotla Groups and the Latest Jurassic Taman and Earliest Cretaceous Pimienta Formations was collected in the southern Sierra Madre Oriental for a palaeomagnetic study. Only the samples from three sites belonging to the Huizachal Group and the Las Juntas Formation possibly have retained their primary magnetization. If so, their pole position does not reveal any palaeomagnetically discernable motion relative to cratonic North America. All remaining sites were remagnetized as evidenced by a negative fold test at four sites and the fact that the pole positions cluster better at the 95% significance level if no structural corrections are applied. The tightness of the cluster ( α95 = 4.6 °) and the same polarity, suggest that the samples were remagnetized at some common time. These results permit two interpretations. (1) If the sampling region has not suffered any significant tectonic rotation, then the remagnetization can be dated by comparison with the polar wander path for North America as Early Cretaceous (≈ 130 Ma). This Early Cretaceous phase of deformation is not recognized in the northern Sierra Madre Oriental and clearly pre-dates the Early Tertiary Laramide orogeny. (2) If the southern Sierra Madre Oriental did rotate counterclockwise by ≈ 20 °, then the remagnetization could have originated in any Cretaceous or Early Tertiary time, and may indeed be related to the Laramide deformation. In either case, the data imply that the southern Sierra Madre Oriental constitutes an independent tectonic domain.

  8. 76 FR 44493 - Revisions to the California State Implementation Plan, Northern Sierra Air Quality Management...

    Science.gov (United States)

    2011-07-26

    ... Management District, Sacramento Metropolitan Air Quality Management District, and South Coast Air Quality... taking direct final action to approve revisions to the Northern Sierra Air Quality Management District (NSAQMD), Sacramento Metropolitan Air Quality Management District (SMAQMD), and South Coast Air Quality...

  9. Sierra Leone's Former Child Soldiers: A Follow-Up Study of Psychosocial Adjustment and Community Reintegration

    Science.gov (United States)

    Betancourt, Theresa Stichick; Borisova, Ivelina Ivanova; Williams, Timothy Philip; Brennan, Robert T.; Whitfield, Theodore H.; de la Soudiere, Marie; Williamson, John; Gilman, Stephen E.

    2010-01-01

    This is the first prospective study to investigate psychosocial adjustment in male and female former child soldiers (ages 10-18; n = 156, 12% female). The study began in Sierra Leone in 2002 and was designed to examine both risk and protective factors in psychosocial adjustment. Over the 2-year period of follow-up, youth who had wounded or killed…

  10. Who cares for former child soldiers? Mental health systems of care in Sierra Leone

    NARCIS (Netherlands)

    Song, S.; van den Brink, H.; de Jong, J.

    2013-01-01

    While numerous studies on former child soldiers (FCS) have shown mental health needs, adequate services are a challenge. This study aimed to identify priorities, barriers and facilitators of mental health care for Sierra Leonean FCS. Thematic analysis was done on 24 qualitative interviews with

  11. Sierra Leone's Former Child Soldiers: A Longitudinal Study of Risk, Protective Factors, and Mental Health

    Science.gov (United States)

    Betancourt, Theresa S.; Brennan, Robert T.; Rubin-Smith, Julia; Fitzmaurice, Garrett M.; Gilman, Stephen E.

    2010-01-01

    Objective: To investigate the longitudinal course of internalizing and externalizing problems and adaptive/prosocial behaviors among Sierra Leonean former child soldiers and whether postconflict factors contribute to adverse or resilient mental health outcomes. Method: Male and female former child soldiers (N = 260, aged 10 to 17 years at…

  12. Señales del cambio global en el sitio LTER-Sierra Nevada

    Directory of Open Access Journals (Sweden)

    A.J. Pérez-Luque

    2016-01-01

    Full Text Available La investigación ecológica a largo plazo proporciona información útil para comprender las complejas dinámicas de los sistemas naturales. Esto se hace especialmente importante en las regiones de montaña como Sierra Nevada, que presenta un fuerte gradiente de condiciones ambientales en una escala espacial pequeña. En el sitio LTER-Sierra Nevada se ha implementado un programa de seguimiento a largo plazo que, junto con la integración de información ecológica sobre los ecosistemas nevadenses, está permitiendo evaluar los efectos del cambio global en esta región de montaña. En este trabajo presentamos algunos resultados de los impactos del cambio global sobre los ecosistemas nevadenses, obtenidos tras varios años de implantación del Observatorio del Cambio Global de Sierra Nevada. Además de una evaluación temporal de los principales motores de cambio global (clima y usos del suelo, presentamos varios casos de estudio del impacto del cambio global sobre la componente biótica y socioeconómica de los ecosistemas de Sierra Nevada.

  13. Die Geologie von Camarena de la Sierra und Riodeva (Provinz Teruel, Spanien)

    NARCIS (Netherlands)

    Wz., R. Martin

    1936-01-01

    Als ich im Jahre 1933 ein Gebiet für meine Feldarbeit suchte, wählte ich auf Veranlassung von Herrn Dr. I. M. van der Vlerk die Gemeinde Camarena de la Sierra südlich von Teruel, wo G. R. J. Terpstra, damals Student der Geologie zu Leiden, im Sommer 1931 eine geologische Aufnahme angefangen hatte,

  14. GPS Imaging of vertical land motion in California and Nevada: Implications for Sierra Nevada uplift

    Science.gov (United States)

    Hammond, William C.; Blewitt, Geoffrey; Kreemer, Corné

    2016-10-01

    We introduce Global Positioning System (GPS) Imaging, a new technique for robust estimation of the vertical velocity field of the Earth's surface, and apply it to the Sierra Nevada Mountain range in the western United States. Starting with vertical position time series from Global Positioning System (GPS) stations, we first estimate vertical velocities using the MIDAS robust trend estimator, which is insensitive to undocumented steps, outliers, seasonality, and heteroscedasticity. Using the Delaunay triangulation of station locations, we then apply a weighted median spatial filter to remove velocity outliers and enhance signals common to multiple stations. Finally, we interpolate the data using weighted median estimation on a grid. The resulting velocity field is temporally and spatially robust and edges in the field remain sharp. Results from data spanning 5-20 years show that the Sierra Nevada is the most rapid and extensive uplift feature in the western United States, rising up to 2 mm/yr along most of the range. The uplift is juxtaposed against domains of subsidence attributable to groundwater withdrawal in California's Central Valley. The uplift boundary is consistently stationary, although uplift is faster over the 2011-2016 period of drought. Uplift patterns are consistent with groundwater extraction and concomitant elastic bedrock uplift, plus slower background tectonic uplift. A discontinuity in the velocity field across the southeastern edge of the Sierra Nevada reveals a contrast in lithospheric strength, suggesting a relationship between late Cenozoic uplift of the southern Sierra Nevada and evolution of the southern Walker Lane.

  15. 77 FR 47536 - Revisions to the California State Implementation Plan, Mojave Desert, Northern Sierra, Sacramento...

    Science.gov (United States)

    2012-08-09

    ... Desert Air Quality Management District. (1) Rule 1116, ``Automotive Refinishing Operations,'' amended on... AGENCY 40 CFR Part 52 Revisions to the California State Implementation Plan, Mojave Desert, Northern... to the Mojave Desert Air Quality Management District (MDAQMD), Northern Sierra ] Air Quality...

  16. Pesticide Distributions and Population Declines of California Alpine Frogs, Rana Muscosa and Rana Sierrae

    Science.gov (United States)

    Atmospherically deposited pesticides from the intensively cultivated Central Valley of California have been implicated as a cause for population declines of several amphibian species, with the strongest evidence for the frogs Rana muscosa and Rana sierrae at high elevation in th...

  17. The Revolutionary United Front and Child Soldiers during Sierra Leone’s Civil War

    Science.gov (United States)

    2015-06-12

    97 Gaviria. 98 Frank Faulkner, “ Kindergarten Killers: Morality, Murder and the Child Soldier Problem...that, “Only the economic opportunity presented by a breakdown in law and order could sustain violence at the levels that plagued Sierra Leone after

  18. Educating Africans for Inferiority under British Rule: Bo School in Sierra Leone.

    Science.gov (United States)

    Corby, Richard A.

    1990-01-01

    Sierra Leone's Bo School was established in 1906 by British colonial officials to educate chiefs' sons for subordinate positions. Nevertheless, the school contributed to creation of the postindependence ruling class. Enrollment, curriculum, student life, responsibilities of British and African teachers, and alumni networks are examined. Contains…

  19. School Persistence in the Wake of War: Wartime Experiences, Reintegration Supports, and Dropout in Sierra Leone

    Science.gov (United States)

    Zuilkowski, Stephanie Simmons; Betancourt, Theresa S.

    2014-01-01

    This article examines the relationship of wartime experience and reintegration supports to students' risk of school dropout. It draws on longitudinal, mixed-methods data collected among children and youth in Sierra Leone from 2002 through 2008. The study finds that family financial support and perceived social support are positively associated…

  20. Achieving a nexus of science, management, and policy in the Sierra Nevada

    Science.gov (United States)

    Peter A. Stine; Dennis D. Murphy

    2004-01-01

    The policies and strategies that guide the use and management of lands in the Sierra Nevada ecoregion depend on objective scientific information. In recent years, the region has attracted increasing attention from visitors, developers, environmentalists, businesses, scientists, and politicians as well as local residents, resource managers, and research groups. And the...

  1. Die Geologie von Camarena de la Sierra und Riodeva (Provinz Teruel, Spanien)

    NARCIS (Netherlands)

    Wz., R. Martin

    1936-01-01

    Als ich im Jahre 1933 ein Gebiet für meine Feldarbeit suchte, wählte ich auf Veranlassung von Herrn Dr. I. M. van der Vlerk die Gemeinde Camarena de la Sierra südlich von Teruel, wo G. R. J. Terpstra, damals Student der Geologie zu Leiden, im Sommer 1931 eine geologische Aufnahme angefangen hatte, w

  2. Concentration-discharge relationships in headwater streams of the Sierra Nevada, California

    Science.gov (United States)

    Carolyn T. Hunsaker; Dale W. Johnson

    2017-01-01

    We examined streamwater concentration-discharge relationships for eight small, forest watersheds ranging in elevation from 1,485 to 2,465 m in the southern Sierra Nevada. These headwater streams revealed nearly chemostatic behavior by current definitions for K+, Ca...

  3. Quantifying the Effects of Wildfire Severity on Snow Water Equivalent in the Sierra Nevada

    Science.gov (United States)

    Nguyen, A.; Cunningham, S.; Sodergren, C.; Anzelc, J.; Cate, N.; Arya, V.

    2015-12-01

    Snowpack in the Sierra Nevada is a crucial component of the California water supply. Climate change effects on forest ecosystems in this region have reduced snowpack and resulted in earlier snowmelt. Wildfire frequency and severity in the Sierra Nevada have also increased, due to higher temperatures, drought, and a legacy of fire suppression policies leading to fuel loads augmented beyond the historic range of variability. These combined factors have the potential to severely impact California water supply. Using 2014 California Basin Characterization Model (BCM) climate data and automated classification of various Landsat imagery, this study geospatially quantified the effects of low, moderate, and high- severity wildfire on snowpack and snow water equivalent (SWE) in the Sierra Nevada. An assessment of modeled SWE data were also conducted to examine its usefulness in better understanding areas effected by wildfire. Results indicate little to no significant change in post-fire SWE for high and moderate severity wildfire, however, delineated a significant decrease in post-fire SWE in the low severity wildfire. Additionally, tests show little no significant change in fractional snow cover post-fire. This use of remote sensing and modeled data will assist in decision and policy making related to management of forest ecosystems and water resources within the Sierra Nevada.

  4. Hacia una Estrategia de Desarrollo para la Sierra Rural en el Perú

    NARCIS (Netherlands)

    Escobal, J.A.; Valdivia, L.

    2004-01-01

    El objetivo de este proyecto es elaborar un documento que establezca los lineamientos de una política de desarrollo para la Sierra rural en el Perú e identificar los requerimientos institucionales y de investigación complementaria que se requerirían para la construcción de programas específicos que

  5. Early Phanerozoic trace fossils from the Sierra Albarrana quartzites (Ossa-Morena Zone, Southwest Spain)

    NARCIS (Netherlands)

    Marcos, A.; Azor, A.; González, F.; Simancas, F.

    1991-01-01

    Three ichnogenera are described from a 50 to 500 m thick shallow-water sandstone-shale sequence (Sierra Albarrana Quartzites). The ichnofauna consists of the burrows of worm-like animals (Arenicolites, Monocraterion, and Skolithos). The age of this formation, previously considered to be Precambrian

  6. The Basement of the Central Andes: The Arequipa and Related Terranes

    Science.gov (United States)

    Ramos, Victor A.

    2008-05-01

    The basement of the Central Andes provides insights for the dispersal of Rodinia, the reconstruction of Gondwana, and the dynamics of terrane accretion along the Pacific. The Paleoproterozoic Arequipa terrane was trapped during collision between Laurentia and Amazonia in the Mesoproterozoic. Ultrahigh-temperature metamorphism correlates with the collapse of the Sunsás-Grenville orogen after 1000 Ma and is related to slab break-off and dispersal of Rodinia. The Antofalla terrane separated in the Neoproterozoic, forming the Puncoviscana basin. Its closure was coeval with the collision of the eastern Sierras Pampeanas. The rift-drift transitions of the early Paleozoic clastic platform showed a gradual younging to the north, in agreement with counterclockwise rotation based on paleomagnetic data of Antofalla. North of Arequipa arc magmatism and high-grade metamorphism are linked to collision of the Paracas terrane in the Ordovician, during the Famatinian orogeny in the Sierras Pampeanas. The early Paleozoic history of the Arequipa massif is explained by a backarc, which further south changed to open oceanic conditions and subsequent collision. The Antofalla terrane reaccreted to the continental margin by the late Ordovician. These accretions and subsequent separations during the Mesoproterozoic, Neoproterozoic early Cambrian, and late Cambrian middle Ordovician are explained by changes in absolute motion of the Gondwana supercontinent during plate global reorganization.

  7. Scaling up family planning in Sierra Leone: A prospective cost-benefit analysis.

    Science.gov (United States)

    Keen, Sarah; Begum, Hashina; Friedman, Howard S; James, Chris D

    2017-08-01

    Family planning is commonly regarded as a highly cost-effective health intervention with wider social and economic benefits. Yet use of family planning services in Sierra Leone is currently low and 25.0% of married women have an unmet need for contraception. This study aims to estimate the costs and benefits of scaling up family planning in Sierra Leone. Using the OneHealth Tool, two scenarios of scaling up family planning coverage to currently married women in Sierra Leone over 2013-2035 were assessed and compared to a 'no-change' counterfactual. Our costing included direct costs of drugs, supplies and personnel time, programme costs and a share of health facility overhead costs. To monetise the benefits, we projected the cost savings of the government providing five essential social services - primary education, child immunisation, malaria prevention, maternal health services and improved drinking water - in the scale-up scenarios compared to the counterfactual. The total population, estimated at 6.1 million in 2013, is projected to reach 8.3 million by 2035 in the high scenario compared to a counterfactual of 9.6 million. We estimate that by 2035, there will be 1400 fewer maternal deaths and 700 fewer infant deaths in the high scenario compared to the counterfactual. Our modelling suggests that total costs of the family planning programme in Sierra Leone will increase from US$4.2 million in 2013 to US$10.6 million a year by 2035 in the high scenario. For every dollar spent on family planning, Sierra Leone is estimated to save US$2.10 in expenditure on the five selected social sector services over the period. There is a strong investment case for scaling up family planning services in Sierra Leone. The ambitious scale-up scenarios have historical precedent in other sub-Saharan African countries, but the extent to which they will be achieved depends on a commitment from both the government and donors to strengthening Sierra Leone's health system post-Ebola.

  8. A new species of Bolitoglossa (Amphibia, Caudata) from the Sierra de Juárez, Oaxaca, Mexico.

    Science.gov (United States)

    Rovito, Sean M; Parra-Olea, Gabriela; Lee, Dana; Wake, David B

    2012-01-01

    We describe a new species of Bolitoglossa (Nanotriton) from the Sierra de Juárez and Sierra Mixe of Oaxaca, Mexico. Bolitoglossa chinantecasp. n. is distinguished from the three other species in the subgenus Nanotriton by its more robust body, by having substantial numbers of maxillary teeth and differences in relative head width, foot width, and limb length. The new species occurs in sympatry with Bolitoglossa (Nanotriton) rufescens at the type locality. The description of another species of salamander from the Sierra de Juárez is noteworthy, given the already high plethodontid salamander species richness of the region.

  9. Population dynamics of spotted owls in the Sierra Nevada, California

    Science.gov (United States)

    Blakesley, J.A.; Seamans, M.E.; Conner, M.M.; Franklin, A.B.; White, Gary C.; Gutierrez, R.J.; Hines, J.E.; Nichols, J.D.; Munton, T.E.; Shaw, D.W.H.; Keane, J.J.; Steger, G.N.; McDonald, T.L.

    2010-01-01

    The California spotted owl (Strix occidentalis occidentalis) is the only spotted owl subspecies not listed as threatened or endangered under the United States Endangered Species Act despite petitions to list it as threatened. We conducted a meta-analysis of population data for 4 populations in the southern Cascades and Sierra Nevada, California, USA, from 1990 to 2005 to assist a listing evaluation by the United States Fish and Wildlife Service. Our study areas (from N to S) were on the Lassen National Forest (LAS), Eldorado National Forest (ELD), Sierra National Forest (SIE), and Sequoia and Kings Canyon National Parks (SKC). These study areas represented a broad spectrum of habitat and management conditions in these mountain ranges. We estimated apparent survival probability, reproductive output, and rate of population change for spotted owls on individual study areas and for all study areas combined (meta-analysis) using model selection or model-averaging based on maximum-likelihood estimation. We followed a formal protocol to conduct this analysis that was similar to other spotted owl meta-analyses. Consistency of field and analytical methods among our studies reduced confounding methodological effects when evaluating results. We used 991 marked spotted owls in the analysis of apparent survival. Apparent survival probability was higher for adult than for subadult owls. There was little difference in apparent survival between male and female owls. Model-averaged mean estimates of apparent survival probability of adult owls varied from 0.811 ?? 0.021 for females at LAS to 0.890 ?? 0.016 for males at SKC. Apparent survival increased over time for owls of all age classes at LAS and SIE, for adults at ELD, and for second-year subadults and adults at SKC. The meta-analysis of apparent survival, which included only adult owls, confirmed an increasing trend in survival over time. Survival rates were higher for owls on SKC than on the other study areas. We analyzed data

  10. Dense Root Removal by Asymmetric Delamination in Sierra Nevada, California: Insights from Numerical Modeling

    Science.gov (United States)

    Valera, J.; Negredo, A. M.; Billen, M.

    2008-12-01

    Recent studies provide compelling evidence for an event of removal of lithospheric mantle in southern -and possibly central- Sierra Nevada (SN) mountains, California (Zandt et al., Nature, 431, 2004). A sequential history of foundering of the ultramafic root of the Sierra Nevada batholith, with a pronounced asymmetric flow, is proposed to explain a number of geophysical and geological observations, including a fast seismic velocity in the mantle located to the west of the SN crest, a gap in the Moho, recent subsidence and tilting of the Sierra Nevada, and a change in mineralogy of the xenolith population recorded at the surface. In the present study we focus on the quantitative evaluation of this conceptual model. We apply new thermo- mechanical algorithms, developed in MATLAB code, suitable to study the temporal evolution of laterally migrating lithospheric delamination. The motion equation, formulated in terms of the stream function, and the coupled thermal equation are solved applying finite difference techniques. Our physical modeling is shown to properly reproduce the first order features of the conceptual model for lithospheric delamination in the Sierra Nevada. We investigate the evolution of a dense ultramafic root, which brings about a Rayleigh-Taylor gravitational instability. Following our preliminary results, the presence of a fluid-weakened lithosphere, located just east of Sierra Nevada, is required to reproduce the asymmetric development of this instability, as previously proposed by Zandt et al. (2004). This weak rheology zone, which is modeled by means of a reduced viscosity, is shown to enable the ascent of asthenospheric material and westward propagation of delamination. Our predictions are also consistent with the previous inference of the V-shaped cone of crust being dragged down into the downwelling mantle (i.e., the Moho gap). Present results highlight that viscous drag is also likely responsible for present-day surface subsidence.

  11. Registro de Nephridiophaga sp. (Protista: Nephridiophagidae en Apis mellifera (Hymenoptera: Apidae del Sur de la región Pampeana Record of Nephridiophaga sp. (Protista: Nephridiophagidae in Apis mellifera (Hymenoptera: Apidae of the southern Pampas

    Directory of Open Access Journals (Sweden)

    Santiago Plischuk

    2011-12-01

    Full Text Available Durante estudios prospectivos tendientes a la detección de protistas asociados a ápidos en la región Pampeana, se observó la presencia de esporos ovales bicóncavos y grupos de esporos (cúmulos en los túbulos de Malpighi de abejas de Dufaur, partido de Saavedra, sudoeste de la provincia de Buenos Aires. Los esporos maduros midieron 4,8 ± 0,05 x 2,4 ± 0,03 μm y la carga (intensidad promedió 5,71 ± 1,49 x 10(6 esporos/abeja. Las detecciones se efectuaron entre julio y octubre de 2006 y la prevalencia en las colmenas positivas osciló entre 1 y 16,7 %. Las características morfológicas de los esporos, el lugar de desarrollo y la especie huésped involucrada sugieren que el microorganismo en cuestión, pertenece al género Nephridiophaga y sería N. apis Ivani, especie tipo cuyo conocimiento es extremadamente limitado. El hallazgo constituye el primer registro de un nefridiofágido asociado a A mellifera fuera del continente europeo.During surveys for the detection of protists associated to Apidae in the Pampas region, biconcave oval spores, and spore clumps were observed in the Malpighian tubules of honeybees from Dufaur, Saavedra county, southwestern Buenos Aires province. Mature spores measured 4.8 ± 0.05 x 2.4 ± 0.03 μm, and mean spore load was 5.71 ± 1.49 x 10(6 per honeybee. Detections were from July to October 2006, and prevalence in positive colonies ranged from 1 to 16.7%. Morphology of the spores, the site of development, and the identity of the host species suggest that the isolated microorganism belongs to the genus Nephridiophaga and would be N apis Ivani, the type species, knowledge on which is extremely limited. The finding constitutes the first record of a nephridiophagid in honeybees outside of Europe.

  12. Avances en el pronóstico climático de las anomalías de lluvia en la Región Pampeana Advances in the climatic forecast of rainfall anomalies in the Pampa Region

    Directory of Open Access Journals (Sweden)

    Juan C. Labraga

    2011-12-01

    Full Text Available Los modelos globales de la circulación general de la atmósfera (MCGA son capaces de simular anomalías climáticas estadísticamente significativas de escala estacional o mayor, asociadas con anomalías en la temperatura de la superficie del mar. Los MCGA pueden estimar efectivamente el signo y la probabilidad de tales anomalías climáticas cuando su extensión es varias veces mayor que la resolución espacial del modelo. En este trabajo se presentan algunos avances en la estimación de las anomalías de la lluvia en 22 localidades de la Región Pampeana Argentina mediante downscaling estadístico de la información producida por un ensamble de veinte simulaciones con el MCGA CSIRO-9, prescribiendo la temperatura de la superficie del mar de acuerdo con los valores diarios observados en el período 1987-1998. El downscaling estadístico de la lluvia produjo una mayor correlación con las observaciones locales que los datos de lluvia del MCGA interpolados sobre cada sitio. Los resultados de un Análisis de las Componentes Principales aplicado a los datos observados y estimados indican que este método de downscaling permite discernir áreas con diferente comportamiento de la lluvia dentro de la región de estudio.Atmospheric general circulation models (AGCM are able to simulate statistically significant climate anomalies of seasonal or larger time-scales, associated with anomalies in the sea surface temperature. AGCMs can effectively estimate the sign and probability of such climate anomalies whenever their extent is several times greater than the spatial resolution of the model. Some progress attained in the estimation of rainfall anomalies in 22 sites of the Pampa Region, Argentina, by means of statistical downscaling of the output from an AGCM are presented in this work. Downscaling models were based in the multiple lineal regression method. Climatic anomalies of the atmospheric independent variables required in the rainfall downscaling

  13. The El Abra stadlal in the Eastern Cordillera of Colombia (South America)

    Science.gov (United States)

    Kuhry, P.; Hooghiemstra, H.; van Geel, B.; van der Hammen, T.

    The El Abra stadial is a climatic cooling event defined in the Eastern Cordillera of Colombia, which corresponds both in timing and intensity to the Younger Dryas climatic oscillation of the northern North Atlantic region. The stadial was preceded by the relatively warm Guantiva interstadial and followed by the warm Holocene. Colder climatic conditions during the El Abra stadial caused a 400 m lowering of the upper Andean forest limit below its altitudinal location during the preceding Guantiva interstadial. Translated in temperature change, this represents a drop in mean annual temperature of approximately 2 to 3°C. The lowering of the upper forest limit and inferred temperature change for the El Abra stadial, compared to Late Holocene conditions, are in the order of 600 m and 4°C, respectively. The transition of the Guantiva interstadial to the El Abra stadial has been radiocarbon dated at 11,210 ± 90 BP and 10,820 ± 60 BP. Climatic warming may have started shortly after 10,380 ± 90 BP, and near present-day temperatures were reached at least as early as 8920 ± 100 BP. Maximum cooling was probably attained between 10,800 BP and 10,300 BP. Further (AMS) radiocarbon dating is planned to establish more exactly the timing of the El Abra stadial. A glacial advance of El Abra age, the Bocatoma stade, has been recognized in the highest part of the Colombian Eastern Cordillera, the Sierra Nevada del Cocuy. During this advance, glaciers extended some 700 m lower than at present. A climatic cooling event of El Abra age, associated with shifts of the upper Andean forest limit and glacial advances, has also been recognized in other parts of Andean Colombia, including the Central Cordillera and the Sierra Nevada de Santa Marta.

  14. Análisis radiocarbónico en una tafocenosis de la región pampeana (provincia de Buenos Aires, Argentina: Su vinculación con la Gran Seca de 1827-1832 Radiocarbon Analysis Of A Taphocenosis From The Pampean Region (Buenos Aires Province, Argentina And Its Relationships With The "Great Drought" Of 1827-1832

    Directory of Open Access Journals (Sweden)

    Eduardo P. Tonni

    2008-12-01

    Full Text Available Se estudió una tafocenosis compuesta por gran número de ejemplares de Equus caballus, Bos taurus y Ovis aries, sin selección etaria. Se realizó una datación radiocarbónica sobre el colágeno del hueso de un húmero de Bos taurus; la fecha obtenida resultó "moderna" (entre 1750 y 1950 AD. Sin embargo, la concentración ΔC14 en el espécimen y su comparación con la curva de concentración ΔC14 para América del Sur, permitió inferir una edad de muerte que corresponde al lapso 1817-1828 AD. La fecha inferida refiere el origen de la tafocenosis a la "Gran Seca", uno de los eventos de sequía más importantes de la región pampeana, sobre el que se tiene registro histórico. Es éste el primer registro paleontológico de un evento de mortandad masiva de ganado relacionado con las frecuentes sequías verificada en la región pampeana durante los siglos XVIII y XIX.A taphocenosis composed of a great number of specimens of Equus caballus, Bos taurus and Ovis aries, without age selection, was analyzed. A radiocarbon date from the bone collagen of a humerus of Bos taurus was obtained; the date is "modern" (between AD 1750 and 1950. However, the 14C concentration of the specimen and its comparison with the South America concentration curve enabled the date to be narrowed down. The inferred date corresponds to the period AD 1817-1828, and suggests that the origin of the taphocenosis is related to the "Gran Seca" ("Great Drought", one of the most important drought events in the Pampeana Region for which there are historical records. This is the first paleontological record of an event of mass death of livestock related to the frequent droughts that affected the Pampean Region during the seventeenth and eighteenth centuries.

  15. A new epigean species of the genus Anelpistina (Insecta: Zygentoma: Nicoletiidae from Sierra de El Abra, Taninul, Mexico

    Directory of Open Access Journals (Sweden)

    Luis Espinasa

    2015-11-01

    Full Text Available Anelpistina taninuli sp. nov. (Insecta: Zygentoma: Nicoletiidae, a species from Taninul, Sierra de El Abra, San Luis Potosi, Mexico, is described. We also report the 16S rRNA sequence of this new species.

  16. Faunistic patterns of leaf beetles (Coleoptera, Chrysomelidae) within elevational and temporal gradients in Sierra de San Carlos, Mexico

    National Research Council Canada - National Science Library

    Sánchez-Reyes, Uriel Jeshua; Niño-Maldonado, Santiago; Barrientos-Lozano, Ludivina; Clark, Shawn M; Jones, Robert W

    2016-01-01

    .... We conducted a faunistic inventory and analyzed the elevational and temporal variation of leaf beetle communities in the Sierra de San Carlos, in the state of Tamaulipas, in northeastern Mexico...

  17. Eastern Siberia terrain intelligence

    Science.gov (United States)

    ,

    1942-01-01

    The following folio of terrain intelligence maps, charts and explanatory tables represent an attempt to bring together available data on natural physical conditions such as will affect military operations in Eastern Siberia. The area covered is the easternmost section of the U.S.S.R.; that is the area east of the Yenisei River. Each map and accompanying table is devoted· to a specialized set of problems; together they cover such subjects as geology, construction materials, mineral fuels, terrain, water supply, rivers and climate. The data is somewhat generalized due to the scale of treatment as well as to the scarcity of basic data. Each of the maps are rated as to reliability according to the reliability scale on the following page. Considerable of the data shown is of an interpretative nature, although precise data from literature was used wherever possible. The maps and tables were compiled  by a special group from the United States Geological Survey in cooperation with the Intelligence Branch of the Office, Chief of Engineers, War Department.

  18. Distribución de elementos traza y grado de fusión parcial en migmatitas de la Sierra de Molinos, Salta Trace element distribution and degree of partial melting in migmatites of Sierra de Molinos, Salta

    Directory of Open Access Journals (Sweden)

    Alfonso Sola

    2012-06-01

    Full Text Available Las migmatitas en facies de anfibolita (alta temperatura/baja presión, HT/LP de la sierra de Molinos, en la Cordillera Oriental, constituyen una excelente oportunidad para estudiar la distribución de elementos traza y estimar el grado de fusión parcial durante el proceso de anatexis, ya que preservan muchas de las estructuras indicativas de una separación casi perfecta entre fundidos y sólidos residuales. Para ello, se obtuvieron series de muestras de leucosomas y melanosomas (4 de metatexitas (zona de Sil-Kfs, mediante una máquina sacatestigos (diámetro = 2,5 cm. Los leucosomas fueron extraídos de sectores dilatantes en una migmatita estromatítica aboudinada, mientras que los melanosomas corresponden a la matriz melanocrática. De esta forma, se logró conseguir la máxima separación entre el material que representa al fundido puro (leucosomas y el residuo sólido dejado por la extracción de éste (melanosoma. Fueron determinados contenidos de elementos mayoritarios y traza a partir de estos pares de muestras, de metapelitas de la Formación Puncoviscana, representativas del protolito, metatexitas y diatexitas leucocráticas. A partir de los pares de leucosomas y melanosomas, considerados como fracciones perfectamente separadas de fundidos y residuos sólidos y utilizando el método de balance de masa, se obtuvieron valores de porcentajes de fusión parcial entre 17-23%. La evaluación de la distribución de elementos traza en fundidos y residuos sólidos, permite conocer la complejidad de procesos de evolución y diversificación de magmas anatécticos, que ocurren cercanos a la fuente. Por ello, estos procesos deben ser tenidos en cuenta a la hora de modelar procesos de fusión parcial utilizando composiciones de rocas graníticas emplazadas en niveles corticales lejanos a la fuente.The amphibolite facies (high temperature/ low pressure; HT/LP migmatites from Sierra de Molinos, Eastern Cordillera, offer an excellent opportunity to

  19. Analysis of Security Sector Reform in Post-Conflict Sierra Leone: A Comparison of Current versus Historical Capabilities

    Science.gov (United States)

    2010-03-01

    Congo; Andrew Dorman. ’The British Experience of Low-Intensity Conflict in Sierra Leone, Defense & Security Analysis 23:2, 191; “Sierra Leone...considerably effective” in combating piracy, smuggling and illegal fishing in its territorial waters, with the craft donated by China having had a considerable...and assisted in the rescue and recovery of several dozen survivors and at least 150 corpses from the stricken vessel.114 Although some families of

  20. Composition of modern sand from the Sierra Nevada, California, USA: Implications for actualistic petrofacies of continental-margin magmatic arcs

    OpenAIRE

    Ingersoll, Raymond V.; Eastmond, Daniel J.

    2007-01-01

    The Sierra Nevada of California represents the roots of a long-lived magmatic arc (primarily Cretaceous) that is presently being dissected as the range is uplifted, beginning in the south and progressing northward. This dissection is occurring concurrently with northward migration of the Mendocino triple junction, south of which magmatic-arc activity is absent, and north of which magmatic-arc activity continues. A north-to-south transect along the Sierra Nevada represents transitions of activ...

  1. Preliminary assessment of the moth (Lepidoptera: Heterocera) fauna of Rincon de Guadalupe, Sierra de Bacadehuachi, Sonora, Mexico

    Science.gov (United States)

    John D. Palting

    2013-01-01

    The Sierra de Bacadéhuachi is a poorly sampled extension of the Sierra Madre Occidental (SMO) located in east-central Sonora near the town of Bacadéhuachi. Sampling of moths using mercury vapor and ultraviolet lights occurred in summer and fall 2011, and spring 2012 at Rincón de Guadalupe, located in pine-oak forest at 1680 m elevation. Approximately 400 taxa of moths...

  2. Geochronologic, Isotopic, and Trace Element Constraints on Zircon Recycling in Sierra Crest Intrusive Suites, Sierra Nevada Batholith, USA

    Science.gov (United States)

    Miller, J. S.; Lackey, J.; Memeti, V.; Hirt, W. H.; Wooden, J. L.

    2011-12-01

    Owing to its ubiquity and chemical properties, zircon is the primary tool for obtaining age information from felsic igneous rocks. Numerous geochronologic studies in ancient and recent plutonic and volcanic rocks over the last decade have shown: (1) that assemblages of zircons from single hand samples rarely crystallized at the same time; (2) that zircons from single hand samples may have variable geochemistry and isotopic compositions requiring distinct growth environments. Nonetheless, the conditions under which diverse assemblages of magmatic zircons crystallize, are dispersed and then gathered within such magma systems are less well understood. We have initiated a systematic geochemical (trace element) and isotopic (δ18O, 176Hf/177Hf) investigation of zircons from dated plutons within several of the Cretaceous Sierran Crest zoned intrusive suites of the Sierra Nevada Batholith to better understand melt sources and zircon recycling within these large magma systems. Preliminary O and Hf isotopic results indicate that zircon assemblages between different intrusive suites have variable isotopic compositions with multiple crustal and mantle sources involved. Preliminary trace element analysis of some of the zircon suites also show appreciable variability but important trends have emerged from the data. In particular, there are pronounced differences between trace element patterns and ratios of the youngest, interior, K-feldspar megacryst-bearing granodiorites (e.g. Cathedral Peak, Mono Creek, Whitney) and the older outer units of the intrusive suites, which are generally more mafic granodiorites and tonalites. In contrast to the more mafic outer units, zircons from the inner megacryst-bearing intrusions are overwhelmingly characterized by low Ti-in-zircon (Tzrn,Ti) model temperatures (regardless of uncertainties in aTiO2), low concentrations of MREEs, high Yb/Gd, low Th/U, high Hf, and high Eu/Eu*. These characteristics, and generally low Zr contents of the

  3. Evaluating potential overlap between pack stock and Sierra Nevada bighorn sheep (Ovis canadensis sierrae) in Sequoia and Kings Canyon National Parks, California

    Science.gov (United States)

    Klinger, Robert C.; Few, Alexandra P.; Knox, Kathleen A.; Hatfield, Brian E.; Clark, Jonathan; German, David W.; Stephenson, Thomas R.

    2015-01-01

    Pack stock (horses, mules, burros, llamas, and goats) are frequently assumed to have negative effects on public lands, but there is a general lack of data to be able to quantify the degree to which this is actually the case. Sequoia and Kings Canyon National Parks have received complaints that pack stock may affect Sierra Nevada bighorn sheep (Ovis canadensis sierrae; SNBS), a federally endangered subspecies that occurs in largely disjunct herds in the Sierra Nevada Range of California. The potential effects are thought to be displacement of SNBS from meadows on their summer range (altered habitat use) or, more indirectly, through changes in SNBS habitat or forage quality. Our goals were to conduct an association analysis to quantify the degree of potential spatial overlap in meadow use between SNBS and pack stock and to compare differences in vegetation community composition, structure, and diversity among meadows with different levels of use by bighorn sheep and pack stock. For the association analysis, we used two approaches: (1) we quantified the proportion of meadows that were within the herd home ranges of bighorn sheep and were potentially open to pack stock, and, (2) we used Monte Carlo simulations and use-availability analyses to compare the proportion of meadows used by bighorn sheep relative to the proportional occurrence or area of meadows available to bighorn sheep that were used by pack stock. To evaluate potential effects of pack stock on meadow plant communities and SNBS forage, we sampled vegetation in 2011 and 2012 at 100 plots to generate data that allowed us to compare:

  4. A new species of Cryptotis (Mammalia, Eulipotyphla, Soricidae) from the Sierra de Perijá, Venezuelan-Colombian Andes

    Science.gov (United States)

    Quiroga-Carmona, Marcial; Woodman, Neal

    2015-01-01

    The Sierra de Perijá is the northern extension of the Cordillera Oriental of the Andes and includes part of the border between Colombia and Venezuela. The population of small-eared shrews (Mammalia, Eulipotyphla, Soricidae, Cryptotis) inhabiting the Sierra de Perijá previously was known from only a single skull from an individual collected in Colombia in 1989. This specimen had been referred to alternatively as C. thomasi and C. meridensis, but more precise definition of the known Colombian and Venezuelan species of Cryptotis has since excluded the Sierra de Perijá population from any named species. The recent collection of a specimen from the Venezuelan slope of Sierra de Perijá, prompted us to re-evaluate the taxonomic status of this population and determine its relationship with other Andean shrews. Our examination of the available specimens revealed that they possess a unique suite of morphological and morphometrical characters, and we describe the Sierra de Perijá population as a new species in the South American C. thomasi species group. Recognition of this new species adds to our knowledge of this genus in South America and to the biodiversity of the Sierra de Perijá.

  5. Evolución de la estructura socioeconómica de la región pampeana argentina. El proceso de concentración de la producción en el período 1988-2008.

    Directory of Open Access Journals (Sweden)

    Diego Ariel Fernández

    2015-01-01

    Full Text Available Este artículo repasa la historia de la estructura socioeconómica de la región pampeana argentina en el período posterior al final de la década de 1980. El objetivo es enmarcar, analizar y comprender lo ocurrido en los tiempos más recientes, en la primera década del siglo XXI. La evidencia procesada permite concluir que la fuerte aceleración del proceso de concentración de la producción que se produjo en los años previos extiende sus efectos al nuevo período. Asimismo, se consolida una nueva estrategia en el crecimiento de la gran empresa, que es la de ganar escalas mediante el arrendamiento

  6. Diversidad de mamíferos de la Reserva Natural Sierra Nanchititla, México Diversity of mammals in the Natural Reserve Sierra Nanchititla, Mexico

    Directory of Open Access Journals (Sweden)

    Octavio Monroy-Vilchis

    2011-03-01

    Full Text Available La Reserva Natural Sierra Nanchititla (RNSN, por su extensión, es la segunda área natural protegida del Estado de México; sin embargo, se desconoce gran parte de su biodiversidad. El objetivo de este trabajo fue estimar su diversidad mastofaunística. Se utilizó el trampeo directo para la colecta de mamíferos pequeños y trampas-cámara para el estudio de los mamíferos medianos y grandes. Se calculó la diversidad a partir del índice de Margalef, y se evaluaron la dominancia y la equidad mediante los índices de Simpson y Shannon-Wiener, respectivamente. Se registraron 53 especies de mamíferos; 3 de ellas son el primer registro estatal, 10 son endémicas de México y 4 las considera en alguna categoría de vulnerabilidad el gobierno mexicano. En la zona habitan 5 de las 6 especies de felinos de México. La composición mastofaunística de la RNSN fue comparada con la de la sierra Purépecha, Michoacán, con la que comparte el 38% de las especies. De acuerdo con el índice de Jaccard, la similitud entre ambas es baja. Considerando los resultados, la importancia de la RNSN con respecto a su diversidad mastofaunística es evidente, así como la necesidad de delinear estrategias para su conservación.The Sierra Nanchititla Natural Reserve (SNNR is the second largest natural protected area in the State of Mexico, however its biodiversity is largely unknown. The aim of this research was to estimate its mammalian diversity. Direct trapping was used to capture small mammals and camera-trapping for the study of medium and large mammals. Diversity was calculated from Margalef's index, dominance and equity were evaluated through Simpson's and Shannon-Wiener indexes, respectively. Fifty three species were registered, 3 of them are the first record for the State of Mexico, 10 are endemic to Mexico and 4 are considered in some category of vulnerability by the Mexican government. The area is inhabited by 5 of the 6 Mexican felid species. The

  7. DATACIONES ARQUEOMAGNÉTICAS EN LA CIUDADELA DE TEOTIHUACAN, SIERRA DE LAS NAVAJAS Y XALASCO (Archaeomagnetic Datings in the Citadel of Teotihuacan, Sierra de las Navajas, and Xalasco

    Directory of Open Access Journals (Sweden)

    Anuar Gabriel Terán Guerrero

    2016-03-01

    Full Text Available El control cronoestratigráfico es fundamental para el desarrollo del trabajo arqueológico, por ello el arqueomagnetismo se ha constituido como una gran herramienta para las dataciones. En este trabajo se muestran los resultados de dataciones arqueomagnéticas mediante la determinación de la dirección de magnetización de pisos de estuco de tres sitios de la cultura teotihuacana: Ciudadela de Teotihuacan, Sierra de las Navajas y Xalasco, Tlaxcala. Esta cultura se desarrolló en el centro de México a partir del año 1 d. C., teniendo su mayor esplendor durante los siglos IV al VI d. C. Tres etapas constructivas fueron muestreadas en la ciudadela de Teotihuacan: la preciudadela, la pirámide de Quetzalcóatl y la pirámide adosada. La Sierra de las Navajas en Hidalgo, a 50 km de Teotihuacan, era su principal proveedor de obsidiana, por lo que es de interés conocer sus periodos de ocupación. El motivo del análisis de los pisos de Xalasco, Tlaxcala, sitio de la cultura teotihuacana, es por encontrarse en la ruta de comunicación con la zona del Golfo de México. Utilizando la metodología y el programa de Pavón-Carrasco et al. (2014 se infieren intervalos de tiempo que nos permiten comprender la dinámica ocupacional de estos sitios. ENGLISH: The chronostratigraphic control is fundamental during any archaeological survey. Recent studies over the Americas showed that archaeomagnetism emerges as a great tool for absolute dating purposes. In this paper, we report new archaeomagnetic datings obtained from stucco floors belonging to three sites of Teotihuacan: the Citadel of Teotihuacan, Sierra de las Navajas and Xalasco, Tlaxcala. This culture developed in central Mexico from AD 1, having its greatest splendor during the 4th to 6th centuries AD. Three construction phases were sampled in the citadel of Teotihuacan: the pre-Citadel, the Pyramid of Quetzalcoatl and the terraced pyramid. The Sierra de la Navajas in Hidalgo, located 50 km from

  8. DATACIONES ARQUEOMAGNÉTICAS EN LA CIUDADELA DE TEOTIHUACAN, SIERRA DE LAS NAVAJAS Y XALASCO (Archaeomagnetic Datings in the Citadel of Teotihuacan, Sierra de las Navajas, and Xalasco)

    OpenAIRE

    Anuar Gabriel Terán Guerrero; Ana María Soler Arechalde; Avto Goguitchaichvili; Cecilia Caballero-Miranda; Juan Morales; Jaime Urrutia-Fucugauchi

    2016-01-01

    El control cronoestratigráfico es fundamental para el desarrollo del trabajo arqueológico, por ello el arqueomagnetismo se ha constituido como una gran herramienta para las dataciones. En este trabajo se muestran los resultados de dataciones arqueomagnéticas mediante la determinación de la dirección de magnetización de pisos de estuco de tres sitios de la cultura teotihuacana: Ciudadela de Teotihuacan, Sierra de las Navajas y Xalasco, Tlaxcala. Esta cultura se desarrolló en el centro de Méxic...

  9. 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.

  10. Observation of cosmic ray hadrons at the top of the Sierra Negra volcano in Mexico with the SciCRT prototype

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, E.; Valdés-Galicia, J. F.; Matsubara, Y.; Nagai, Y.; Hurtado, A.; Musalem, O.; García, R.; Anzorena, M. A.; González, L. X.; Itow, Y.; Sako, T.; Lopez, D.; Sasai, Y.; Munakata, K.; Kato, C.; Kozai, M.; Shibata, S.; Takamaru, H.; Kojima, H.; Watanabe, K.; Tsuchiya, H.; Koi, T.

    2016-11-01

    In this work we report the flux of protons and neutral emission measured at the top of the Sierra Negra volcano at 4600 m.a.s.l. (575 g/cm2), in Eastern Mexico. As an example of the capability of the mini-SciCR as a cosmic ray detector we present the Forbush decrease recorded on March 7, 2012. These data were obtained with a cosmic ray detector prototype called mini-SciCR that was operating from October 2010 to July 2012. Our main aims were to measure the hadronic component flux of the secondary cosmic ray and to show the appropriate performance of all system of the detector. To separate the signals of protons from other charged particles we obtained the energy deposition pattern when they cross the detector using a Monte Carlo simulation, and to separate the signals of neutral emission we used an anticoincidence system between the edge bars and the internal bars of the detector. The mini-SciCR is a prototype of a new cosmic ray detector called SciBar Cosmic Ray Telescope (SciCRT) installed in the same place, which is in the process of calibration. The SciCRT will work mainly as a Solar Neutron and Muon Telescope, it is designed to achieve: (1) larger effective area than the current Solar Neutron Telescope, (2) higher energy resolution to determine the energy spectrum of solar neutrons, (3) lower energy threshold, and (4) higher particle identification ability.

  11. Observation of cosmic ray hadrons at the top of the Sierra Negra volcano in Mexico with the SciCRT prototype

    Science.gov (United States)

    Ortiz, E.; Valdés-Galicia, J. F.; Matsubara, Y.; Nagai, Y.; Hurtado, A.; Musalem, O.; García, R.; Anzorena, M. A.; González, L. X.; Itow, Y.; Sako, T.; Lopez, D.; Sasai, Y.; Munakata, K.; Kato, C.; Kozai, M.; Shibata, S.; Takamaru, H.; Kojima, H.; Watanabe, K.; Tsuchiya, H.; Koi, T.

    2016-11-01

    In this work we report the flux of protons and neutral emission measured at the top of the Sierra Negra volcano at 4600 m.a.s.l. (575 g/cm2), in Eastern Mexico. As an example of the capability of the mini-SciCR as a cosmic ray detector we present the Forbush decrease recorded on March 7, 2012. These data were obtained with a cosmic ray detector prototype called mini-SciCR that was operating from October 2010 to July 2012. Our main aims were to measure the hadronic component flux of the secondary cosmic ray and to show the appropriate performance of all system of the detector. To separate the signals of protons from other charged particles we obtained the energy deposition pattern when they cross the detector using a Monte Carlo simulation, and to separate the signals of neutral emission we used an anticoincidence system between the edge bars and the internal bars of the detector. The mini-SciCR is a prototype of a new cosmic ray detector called SciBar Cosmic Ray Telescope (SciCRT) installed in the same place, which is in the process of calibration. The SciCRT will work mainly as a Solar Neutron and Muon Telescope, it is designed to achieve: (1) larger effective area than the current Solar Neutron Telescope, (2) higher energy resolution to determine the energy spectrum of solar neutrons, (3) lower energy threshold, and (4) higher particle identification ability.

  12. Holocene hydrologic variability in the Sierra Nevada from D/H ratios in leaf waxes

    Science.gov (United States)

    Street, J. H.; Sessions, A. L.; Anderson, R. S.; Welker, J. M.; Paytan, A.

    2009-12-01

    Large-scale atmospheric circulation patterns and underlying ocean conditions in the Northeastern Pacific have a strong bearing on continental climate conditions and water availability in California on seasonal to decadal timescales, as demonstrated in the instrumental record. However, the nature and pacing of the relationship between ocean-atmosphere processes and hydrologic variability in California remain poorly understood over longer timescales and during past climate regimes of the Holocene and late Pleistocene, particularly in the large Sacramento-San Joaquin River watershed draining the western Sierra Nevada. The continuous ~20,000-yr sedimentary record recovered from Swamp Lake, a small mid-elevation (1554 m) lake in Yosemite NP, provides a rare opportunity to reconstruct hydrologic variability in the central Sierra Nevada at high resolution (Mt. Logan ice core record and drought cycles northern and central California.

  13. A Late Proterozoic Early Paleozoic magmatic cycle in Sierra de la Ventana, Argentina

    Science.gov (United States)

    Gregori, D. A.; López, V. L.; Grecco, L. E.

    2005-06-01

    Late Proterozoic-Early Paleozoic intrusive and volcanic rocks of Sierra de la Ventana can be grouped into two magmatic assemblages: the Meyer and Cochenleufú suites. The older (700-570 Ma) is composed of S-type quartz-monzodiorites, synogranites, and monzogranites associated with andesites and rhyolites and related to volcanic-arc and postcollisional settings. The younger (540-470 Ma) corresponds to highly fractionated homogeneous A-type monzogranites, linked to final plutonic events during postorogenic extension in collisional belts. Strong similarities between Sierra de la Ventana magmatic rocks and the S- and A-type granites of the Cape granite suite in South Africa allow positive correlation. In both areas, primitive volcanic arcs or collisional orogens are recognized. Continuous transpressional shearing between the Swartland and Tygerberg terranes in the Saldania belt may have triggered the generation and emplacement of both suites.

  14. A new species of Rhadinella (Serpentes: Colubridae) from the Sierra Madre del Sur of Guerrero, Mexico.

    Science.gov (United States)

    Campillo, Gustavo; Dávila-Galavíz, Luis Fernando; Flores-Villela, Oscar; Campbell, Jonathan A

    2016-04-12

    We describe a new species of Rhadinella from the Sierra Madre del Sur of Guerrero, Mexico, a region where the genus was previously unknown. This diminutive species is a member of a group of snakes previously allocated in the Rhadinaea godmani group, and more recently transferred to the genus Rhadinella. These snakes may have conspicuous dark longitudinal striping on a pale brown to orange background or may have dark brown to blackish dorsal ground coloration, which mostly or completely obfuscates a pattern of longitudinal striping. The new species is mostly dark with barely discernible slightly paler or darker striping (depending on how striping is interpreted). The closest relative of the new species, on the basis of morphological similarities and biogeography, appears to be Rhadinella donaji which occurs to the east in the Sierra Madre del Sur of Oaxaca about 275 km from the type-locality of the new species.

  15. Propuesta para la construcción del concepto de interculturalldad caso la sierra nevada

    Directory of Open Access Journals (Sweden)

    Julio Marino Barragán

    2014-02-01

    Full Text Available La imponente Sierra Nevada de Santa Marta controla buena parte del clima de toda la  región, gracias a la montaña sagrada los huracanes no son tan devastadores como sí la son por otras latitudes. Así como la Sierra, el  departamento del Magdalena es una de las regiones culturales más ricas del país y de la cuenca del Caribe. En el Magdalena encontramos poblados típicos de la múltiple mezcla, del mestizaje de los sinnúmeros de vertientes culturales que se arriesgan a venir por estas tierras, desde el cercano oriente, la esteparia Rusia.

  16. Thymus × pseudogranatensis (Labiatae, nuevo híbrido para Sierra Nevada (España

    Directory of Open Access Journals (Sweden)

    Lorite, Juan

    2011-12-01

    Full Text Available Thymus × pseudogranatensis Vizoso, F.B. Navarro & Lorite, a new spontaneous hybrid of Th. granatensis Boiss. subsp. granatensis and Th. zygis L. subsp. gracilis (Boiss. R. Morales, collected in the dolomitic areas of Sierra Nevada (SE Spain, is described. Morphological characters of the new nothospecies are analysed and its distribution and ecology are discussed.Se describe Thymus × pseudogranatensis Vizoso, F.B. Navarro & Lorite, un nuevo híbrido entre Th. granatensis Boiss. subsp. granatensis y Th. zygis L. subsp. gracilis (Boiss. R. Morales, colectado en la orla dolomítica de Sierra Nevada (SE de España. Se analizan los caracteres morfológicos de la nueva notoespecie y se aportan detalles sobre su hábitat y distribución.

  17. Pesticides Are Involved With Population Declines of Amphibians in the California Sierra Nevadas

    Directory of Open Access Journals (Sweden)

    Donald W. Sparling

    2001-01-01

    Full Text Available Several species of frogs and toads are in serious decline in the Sierra Nevada Mountains of California. These species include the threatened red-legged frog (Rana aurora, foothill yellow-legged frog (R. boylii, mountain yellow-legged frog (R. muscosa, Cascades frog (Rana cascadae, western toad (Bufo boreas and Yosemite toad (B. canorus. For many of these species current distributions are down to 10% of historical ranges [1,2]. Several factors including introduced predators [3,4,5], habitat loss [2], and ultraviolet radiation [6] have been suggested as causes of these declines. Another probable cause is air-borne pesticides from the Central Valley of California. The Central Valley, especially the San Joaquin Valley, is a major agricultural region where millions of pounds of active ingredient pesticides are applied each year (http://www.cdpr.ca.gov/dprdatabase.htm. Prevailing westerly winds from the Pacific Coast transport these pesticides into the Sierras [7,8].

  18. Comprehensive yet scalable health information systems for low resource settings: a collaborative effort in sierra leone.

    Science.gov (United States)

    Braa, Jørn; Kanter, Andrew S; Lesh, Neal; Crichton, Ryan; Jolliffe, Bob; Sæbø, Johan; Kossi, Edem; Seebregts, Christopher J

    2010-11-13

    We address the problem of how to integrate health information systems in low-income African countries in which technical infrastructure and human resources vary wildly within countries. We describe a set of tools to meet the needs of different service areas including managing aggregate indicators, patient level record systems, and mobile tools for community outreach. We present the case of Sierra Leone and use this case to motivate and illustrate an architecture that allows us to provide services at each level of the health system (national, regional, facility and community) and provide different configurations of the tools as appropriate for the individual area. Finally, we present a, collaborative implementation of this approach in Sierra Leone.

  19. Estimating aboveground biomass for broadleaf woody plants and young conifers in Sierra Nevada, California forests.

    Science.gov (United States)

    McGinnis, Thomas W.; Shook, Christine D.; Keeley, Jon E.

    2010-01-01

    Quantification of biomass is fundamental to a wide range of research and natural resource management goals. An accurate estimation of plant biomass is essential to predict potential fire behavior, calculate carbon sequestration for global climate change research, assess critical wildlife habitat, and so forth. Reliable allometric equations from simple field measurements are necessary for efficient evaluation of plant biomass. However, allometric equations are not available for many common woody plant taxa in the Sierra Nevada. In this report, we present more than 200 regression equations for the Sierra Nevada western slope that relate crown diameter, plant height, crown volume, stem diameter, and both crown diameter and height to the dry weight of foliage, branches, and entire aboveground biomass. Destructive sampling methods resulted in regression equations that accurately predict biomass from one or two simple, nondestructive field measurements. The tables presented here will allow researchers and natural resource managers to easily choose the best equations to fit their biomass assessment needs.

  20. High altitude wind velocity at Sierra Negra and San Pedro M\\'artir

    CERN Document Server

    Carrasco, E; Carramiñana, A; Carrasco, Esperanza; Avila, Remy; Carrami\\~nana, Alberto

    2004-01-01

    It has been proposed that the global circulation of the atmosphere winds at 200 mb can be used as a criteria to establish the suitability of a site for the development of adaptive optics techniques such as slow wavefront corrugation correction. By using the NOAA NCEP/NCAR Reanalysis data base we analyze the monthly average wind velocity at 200 mb for a 16 year period, for two sites in Mexico: Sierra Negra and San Pedro M\\'artir. We compare the results with those obtained for Mauna Kea, Paranal and La Silla, with Maidanak in Uzbekistan, and with Gamsberg in Namibia. We show that for all the sites under study there is a yearly wind speed modulation and we model that modulation. Our results show that Sierra Negra and San Pedro M\\'artir are comparable with the best observatory sites as Mauna Kea and are amongst the most advantageous sites to apply adaptive optics techniques.

  1. Medium and large mammals in the Sierra La Madera, Sonora, Mexico

    Science.gov (United States)

    Erick Oswaldo Bermudez-Enriquez; Rosa Elena Jimenez-Maldonado; Gertrudis Yanes-Arvayo; Maria de la Paz Montanez-Armenta; Hugo Silva-Kurumiya

    2013-01-01

    Sierra La Madera is a Sky Island mountain range in the Madrean Archipelago. It is in Fracción V of the Ajos-Bavispe CONANP Reserve in the Municipios (= Counties) of Cumpas, Granados, Huásabas, Moctezuma, and Villa Hidalgo. Medium and large mammals were inventoried using camera traps. Eighteen Wild View 2® camera traps were deployed during four sampling periods: August...

  2. Hydrologic response and watershed sensitivity to climate warming in California's Sierra Nevada.

    Science.gov (United States)

    Null, Sarah E; Viers, Joshua H; Mount, Jeffrey F

    2010-04-01

    This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2 degrees, 4 degrees, and 6 degrees C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds.

  3. Hydrologic response and watershed sensitivity to climate warming in California's Sierra Nevada.

    Directory of Open Access Journals (Sweden)

    Sarah E Null

    Full Text Available This study focuses on the differential hydrologic response of individual watersheds to climate warming within the Sierra Nevada mountain region of California. We describe climate warming models for 15 west-slope Sierra Nevada watersheds in California under unimpaired conditions using WEAP21, a weekly one-dimensional rainfall-runoff model. Incremental climate warming alternatives increase air temperature uniformly by 2 degrees, 4 degrees, and 6 degrees C, but leave other climatic variables unchanged from observed values. Results are analyzed for changes in mean annual flow, peak runoff timing, and duration of low flow conditions to highlight which watersheds are most resilient to climate warming within a region, and how individual watersheds may be affected by changes to runoff quantity and timing. Results are compared with current water resources development and ecosystem services in each watershed to gain insight into how regional climate warming may affect water supply, hydropower generation, and montane ecosystems. Overall, watersheds in the northern Sierra Nevada are most vulnerable to decreased mean annual flow, southern-central watersheds are most susceptible to runoff timing changes, and the central portion of the range is most affected by longer periods with low flow conditions. Modeling results suggest the American and Mokelumne Rivers are most vulnerable to all three metrics, and the Kern River is the most resilient, in part from the high elevations of the watershed. Our research seeks to bridge information gaps between climate change modeling and regional management planning, helping to incorporate climate change into the development of regional adaptation strategies for Sierra Nevada watersheds.

  4. Transmission dynamics of Ebola virus disease and intervention effectiveness in Sierra Leone.

    Science.gov (United States)

    Fang, Li-Qun; Yang, Yang; Jiang, Jia-Fu; Yao, Hong-Wu; Kargbo, David; Li, Xin-Lou; Jiang, Bao-Gui; Kargbo, Brima; Tong, Yi-Gang; Wang, Ya-Wei; Liu, Kun; Kamara, Abdul; Dafae, Foday; Kanu, Alex; Jiang, Rui-Ruo; Sun, Ye; Sun, Ruo-Xi; Chen, Wan-Jun; Ma, Mai-Juan; Dean, Natalie E; Thomas, Harold; Longini, Ira M; Halloran, M Elizabeth; Cao, Wu-Chun

    2016-04-19

    Sierra Leone is the most severely affected country by an unprecedented outbreak of Ebola virus disease (EVD) in West Africa. Although successfully contained, the transmission dynamics of EVD and the impact of interventions in the country remain unclear. We established a database of confirmed and suspected EVD cases from May 2014 to September 2015 in Sierra Leone and mapped the spatiotemporal distribution of cases at the chiefdom level. A Poisson transmission model revealed that the transmissibility at the chiefdom level, estimated as the average number of secondary infections caused by a patient per week, was reduced by 43% [95% confidence interval (CI): 30%, 52%] after October 2014, when the strategic plan of the United Nations Mission for Emergency Ebola Response was initiated, and by 65% (95% CI: 57%, 71%) after the end of December 2014, when 100% case isolation and safe burials were essentially achieved, both compared with before October 2014. Population density, proximity to Ebola treatment centers, cropland coverage, and atmospheric temperature were associated with EVD transmission. The household secondary attack rate (SAR) was estimated to be 0.059 (95% CI: 0.050, 0.070) for the overall outbreak. The household SAR was reduced by 82%, from 0.093 to 0.017, after the nationwide campaign to achieve 100% case isolation and safe burials had been conducted. This study provides a complete overview of the transmission dynamics of the 2014-2015 EVD outbreak in Sierra Leone at both chiefdom and household levels. The interventions implemented in Sierra Leone seem effective in containing the epidemic, particularly in interrupting household transmission.

  5. Structural pattern in central uplifts of cryptoexplosion structures as typified by Sierra Madera

    Science.gov (United States)

    Wilshire, H.G.; Howard, K.A.

    1968-01-01

    The pattern of deformation in central uplifts of Sierra Madera and other well-known cryptoexplosion structures indicates that inward as well as upward movement of strata formed the uplifts. This kind of movement is incompatible with structures not of impact origin with which they have been compared. The structural style of cryptoexplosion structures, together with features that suggest shock deformation, supports the belief that they are the eroded roots of impact craters.

  6. Ecology of the Scorpion, Microtityus jaumei in Sierra de Canasta, Cuba

    Science.gov (United States)

    Cala-Riquelme, Franklyn; Colombo, Marco

    2011-01-01

    An assessment of the population dynamics of Microtityus jaumei Armas (Scorpiones: Buthidae) on the slopes south of Sierra de Canasta, Guantánamo Province, Cuba show an increase in activity over the year (≤ 0.05). The activity peak is related to the reproductive period from June to November. The abundance of scorpions was significantly related to density of the canopy and thickness of the substrate. PMID:21870972

  7. Sierra Chata field, Argentina: geophysical discovery and development of a stratigraphic trap

    Energy Technology Data Exchange (ETDEWEB)

    Woller, Kevin L. [Mobil Technology Co. (United States); Louder, William T. [Santa Fe Energy Resources (Argentina)

    1999-07-01

    Drilling a seismic amplitude anomaly in the Cretaceous Mulichinco Sandstone discovered the Sierra Chata gas field in the Neuquen Basin, Argentina. This well followed several unsuccessful attempts to locate hydrocarbons in the block, including a well only 3 kilometers from the closet producing well in the field. Since that time, seismic data has played the major role in locating new wells, all 24 of which have been completed as producers. (author)

  8. Inversion for Eigenvalues and Modes Using Sierra-SD and ROL.

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Timothy [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Aquino, Wilkins [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ridzal, Denis [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kouri, Drew Philip [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    In this report we formulate eigenvalue-based methods for model calibration using a PDE-constrained optimization framework. We derive the abstract optimization operators from first principles and implement these methods using Sierra-SD and the Rapid Optimization Library (ROL). To demon- strate this approach, we use experimental measurements and an inverse solution to compute the joint and elastic foam properties of a low-fidelity unit (LFU) model.

  9. DIAGNOSIS IMPORTANCE OF RURAL DEVELOPMENT OF A MODEL AGROFORESTAL IN PEASANT COMMUNITIES OF SIERRA DE HUAUTLA

    OpenAIRE

    Miguel Uribe-Gómez; Artemio Cruz-León; Dionicio Juárez-Ramón; Alejandro Lara-Bueno; José L. Romo-Lozano; Ramón Valdivia-Alcalá; Marcos Portillo-Vázquez

    2015-01-01

    Family agricultural is socioeconomically important in rural areas, but in Mexico, from the 80's this production system presents social stagnation. This type of agriculture presents a dynamic reality in the interests of each producer and limiting access to factors of production (land, labor and capital). In this investigation a methodology for analysis and diagnosis of production systems in rural areas, in two communities in the Country Sierra de Huautla Tepalcingo, Morelos, Mexico was applied...

  10. Ten Years of Forest Cover Change in the Sierra Nevada Detected Using Landsat Satellite Image Analysis

    Science.gov (United States)

    Potter, Christopher S.

    2014-01-01

    A detailed geographic record of recent vegetation regrowth and disturbance patterns in forests of the Sierra Nevada remains a gap that can be filled with remote sensing data. Landsat (TM) imagery was analyzed to detect 10 years of recent changes (between 2000 and 2009) in forest vegetation cover for areas burned by wildfires between years of 1995 to 1999 in the region. Results confirmed the prevalence of regrowing forest vegetation during the period 2000 and 2009 over 17% of the combined burned areas.

  11. Resilience Through Disturbance: Effects of Wildfire on Vegetation and Water Balance in the Sierra Nevadas

    Science.gov (United States)

    Boisrame, G. F. S.; Thompson, S. E.; Stephens, S.; Collins, B.; Tague, N.

    2015-12-01

    A century of fire suppression in the Western United States has drastically altered the historically fire-adapated ecology in California's Sierra Nevada Mountains. Fire suppression is understood to have increased the forest cover, as well as the stem density, canopy cover and water demand of montane forests, reducing resilience of the forests to drought, and increasing the risk of catastrophic fire by drying the landscape and increasing fuel loads. The potential to reverse these trends by re-introducing fire into the Sierra Nevada is highly promising, but the likely effects on vegetation structure and water balance are poorly quantified. The Illilouette Creek Basin in Yosemite National Park represents a unique experiment in the Sierra Nevada, in which managers have moved from fire suppression to allowing a near-natural fire regime to prevail since 1972. Changes in vegetation structure in the Illilouette since the restoration of natural burning provides a unique opportunity to examine how frequent, mixed severity fires can reshape the Sierra Nevada landscape. We characterize these changes from 1969 to the present using a combination of Landsat products and high-resolution aerial imagery. We describe how the landscape structure has changed in terms of vegetation composition and its spatial organization, and explore the drivers of different post-fire vegetation type transitions (e.g. forest to shrubland vs. forest to meadow). By upscaling field data using vegetation maps and Landsat wetness indices, we explore how these vegetation transitions have impacted the water balance of the Illilouette Creek Basin, potentially increasing its resilience in the face of drought, climate change, and catastrophic fire. In a region that is adapted to frequent disturbance from fire, this work helps us understand how allowing such natural disturbances to take place can increase the sustainability of diverse landscapes in the long term.

  12. Impact of Summer Cattle Grazing on the Sierra Nevada Watershed: Aquatic Algae and Bacteria

    OpenAIRE

    2012-01-01

    Introduction. We evaluated periphytic algal and microbial communities to assess the influence of human and cattle impact on Sierra water quality. Methods. 64 sites (lakes and streams from Lake Tahoe to Sequoia National Park, California) were sampled for suspended indicator bacteria and algae following standardized procedures. The potential for nonpoint pollution was divided into three categories: cattle-grazing areas (C), recreation use areas (R), or remote wildlife areas (W). Results. Periph...

  13. Gravity change from 2014 to 2015, Sierra Vista Subwatershed, Upper San Pedro Basin, Arizona

    Science.gov (United States)

    Kennedy, Jeffrey R.

    2016-01-01

    Relative-gravity data and absolute-gravity data were collected in the Sierra Vista Subwatershed, Upper San Pedro Basin, Arizona, in May–June 2014 and 2015. Data from 2014 and a description of the survey network were published in USGS Open-File Report 2015–1086. Data presented in the shapefile here are the following:(1) Network-adjusted values from 2015,(2) Gravity change from 2014 to 2015, and(3) Survey-grade coordinates obtained from a Global Positioning System (GPS) survey in 2015. 2015 data and network adjustment results are presented in Kennedy, J.R., 2016, Gravity change from 2014 to 2015, Sierra Vista Subwatershed, Upper San Pedro Basin, Arizona: U.S. Geological Survey Open–File Report 2016–1155, 15 p., http://dx.doi.org/10.3133/ofr201611552014 data and network adjustment results are presented inKennedy, J.R., 2015, Gravity data from the Sierra Vista Subwatershed, Upper San Pedro Basin, Arizona: U.S. Geological Survey Open–File Report 2015–1086, 26 p., http://dx.doi.org/10.3133/ofr20151086

  14. Changes in precipitating snow chemistry with location and elevation in the California Sierra Nevada

    Science.gov (United States)

    Creamean, Jessie M.; Axson, Jessica L.; Bondy, Amy L.; Craig, Rebecca L.; May, Nathaniel W.; Shen, Hongru; Weber, Michael H.; Pratt, Kerri A.; Ault, Andrew P.

    2016-06-01

    Orographic snowfall in the Sierra Nevada Mountains is an important source of water for California and can vary significantly on an annual basis. The microphysical properties of orographic clouds and subsequent formation of precipitation are impacted, in part, by aerosols of varying size, number, and chemical composition, which are incorporated into clouds formed along the Sierra barrier. Herein, the physicochemical properties and sources of insoluble residues and soluble ions found in precipitation samples were explored for three sites of variable elevation in the Sierra Nevada during the 2012-2013 winter season. Residues were characterized using a suite of physicochemical techniques to determine the size-resolved number concentrations and associated chemical composition. A transition in the aerosol sources that served as cloud seeds or were scavenged in-cloud and below-cloud was observed as a function of location and elevation. Anthropogenic influence from the Central Valley was dominant at the two lowest elevation sites (1900 and 2200 m above mean sea level (AMSL)), whereas long-range transported mineral dust was a larger contributor at the highest elevation site where cleaner conditions were observed (2600 m AMSL). The residues and soluble ions observed provide insight into how multiple aerosol sources can impact cloud and precipitation formation processes, even over relatively small spatial scales. The transition with increasing elevation to aerosols that serve as ice nucleating particles may impact the properties and extent of snowfall in remote mountain regions where snowpack provides a vital supply of water.

  15. Chinese military medical teams in the Ebola outbreak of Sierra Leone.

    Science.gov (United States)

    Lu, Yinying; Rong, G; Yu, S P; Sun, Z; Duan, X; Dong, Z; Xia, H; Zhan, N; Jin, C; Ji, J; Duan, H

    2016-06-01

    The 2014-2015 Ebola virus disease (EVD) epidemic in West Africa was the largest in history. The three most affected countries, Guinea, Liberia and Sierra Leone, have faced enormous challenges in controlling transmission and providing clinical care for patients with EVD. The Chinese government, in response to the requests of the WHO and the governments of the affected countries, responded rapidly by deploying Chinese military medical teams (CMMTs) to the areas struck by the deadly epidemic. A total of three CMMTs, comprising 115 military medical professionals, were rotationally deployed to Freetown, Sierra Leone to assist with infection prevention and control, clinical care and health promotion and training. Between 1 October 2014 and 22 March 2015, the CMMTs in Sierra Leone admitted and treated a total of 773 suspected and 285 confirmed EVD cases. Among the 285 confirmed cases, 146 (51.2%) patients survived after treatment. In addition, the CMMTs maintained the record of zero infections among healthcare workers and zero cross-infections between quarantined patients. In this manuscript, we aim to give an overview of the mission, and share our best practices experience on predeployment preparedness, EVD holding and treatment centre building and EVD case management. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  16. Containing Ebola: A Test for Post-Conflict Security Sector Reform in Sierra Leone

    Directory of Open Access Journals (Sweden)

    Cathy Haenlein

    2015-07-01

    Full Text Available Ebola has provided the greatest test of the Sierra Leonean security sector – and, in turn, of the UK-led reforms of the past ten-to-fifteen years. The performance of the country's security forces at the height of the crisis suggests that there are sound structures in place; however, Ebola has shown that the Government of Sierra Leone's national security architecture still lacks maturity in responding to such a scenario. Drawing on first-hand interviews with advisers on the ground, this article explores the Sierra Leone government’s response to the Ebola crisis and the performance of the security sector so far, within the wider context of UK-led security-sector reform (SSR since the end of the civil war. In doing so, it highlights a number of lessons to have emerged from the crisis, exploring what these reveal about the nature of the reforms implemented since the end of the country's civil war. In turn, it explores what these suggest for future SSR, which continues to be a core component of the UK’s approach to development and overseas capacity-building.

  17. New Records of Phlebotomine Sandflies (Diptera: Psychodidae at Sierra Nevada de Santa Marta, Colombia

    Directory of Open Access Journals (Sweden)

    Eduar Elías BEJARANO

    2014-09-01

    Full Text Available NUEVOS HALLAZGOS DE FLEBOTOMÍNEOS (DIPTERA: PSYCHODIDAE EN LA SIERRA NEVADA DE SANTA MARTA, COLOMBIAEl componente entomológico de la leishmaniasis ha sido poco estudiado en la Sierra Nevada de Santa Marta, Colombia, incluido el departamento del Magdalena, donde a la fecha están registradas trece especies de Lutzomyia. En la presente nota se informa el hallazgo de tres especies y un subgénero más en la región. Se recolectaron 885 flebotomíneos en Seywiaka y las veredas Las Tinajas y Calabazo, estribaciones de la Sierra Nevada de Santa Marta (117-130 m.s.n.m.. El 84% de los ejemplares se obtuvieron con trampa CDC, el 11% con trampa Shannon y el 5% fueron capturados, en reposo, con un dispositivo eléctrico de succión.  Se identificaron nueve especies, Lu. gomezi, Lu. panamensis, Lu. trinidadensis, Lu. carpenteri, Lu. evansi, Lu. dysponeta, Lu. dubitans, Lu. shannoni, y Lu. micropyga, la más abundante fue Lu. gomezi (69%, seguida por Lu. panamensis (14%. También se recolectaron ejemplares de la serie Lu. osornoi del subgénero Helcocyrtomyia. Entre el material hallado sobresalen Lu. carpenteri, Lu. dubitans y Lu. dysponeta como primeros registros para el departamento del Magdalena, además de Lu. (Helcocyrtomyia sp., que representa el primer hallazgo del subgénero en el Caribe colombiano.

  18. Herbs and herbal combinations used to treat suspected malaria in Bo, Sierra Leone.

    Science.gov (United States)

    Ranasinghe, Shamika; Ansumana, Rashid; Lamin, Joseph M; Bockarie, Alfred S; Bangura, Umaru; Buanie, Jacob A G; Stenger, David A; Jacobsen, Kathryn H

    2015-05-26

    Most adults in West Africa treat acute febrile illnesses with local herbs, but the patterns of herbs used for malaria have not been recently described in Sierra Leone. We used a population-based cross-sectional approach to interview 810 randomly-sampled rural and urban adult residents of Bo, Sierra Leone, in December 2013 and January 2014 about their use of herbal remedies when they suspect they have malaria. In total, 55% of the participants reported taking one or more of seven herbs to treat symptoms of malaria. Among herb users, the most commonly used anti-malarial herbs were Moringa oleifera (moringa, 52%) and Sarcocephalus latifolius (yumbuyambay, 50%). The other herbs used included Senna siamea (shekutoure, 18%), Cassia sieberiana (gbangba, 18%), Uvaria afzelii (gone-botai, 14%), Morinda chrysorhiza (njasui, 14%), and Craterispermum laurinum (nyelleh, 7%). Combination herbal therapy was common, with 37% of herb users taking two or more herbs together when ill with suspected malaria. Indigenous medical knowledge about herbal remedies and combinations of local herbs remains an integral part of malaria case management in Sierra Leone. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2017-02-01

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

  20. Handling postpartum haemorrhage- obstetrics between tradition and modernity in post-war Sierra Leone.

    Science.gov (United States)

    Bräuer, Miriam Dorothea; Antón, Jorge; George, Peter Matthew; Kuntner, Liselotte; Wacker, Jürgen

    2015-04-01

    How traditional birth attendants (TBAs) in post-war Sierra Leone explain, handle and prevent postpartum haemorrhage (PPH) and their potential role in a better management of PPH to reduce maternal mortality in this low resource setting. Semi-quantitative interviews about knowledge and measures in PPH and participant observation with 140 Sierra Leonean birth attendants, divided in three groups: (A) TBAs who never attended any official training course (n = 82); (B) TBAs who attended at least one official training course (n = 48); and (C) officially trained birth attendants (n = 10). There are several observable gaps in the knowledge of TBAs about PPH compared to modern obstetrics, however similar procedures exist. Herbal medicine is applied; metaphysical convictions about PPH remain present. Training courses show an impact. Officially trained birth attendants demonstrate knowledge deficiencies and lack resources and infrastructure to manage PPH adequately. Morbidity and mortality of PPH in Sierra Leone is related to several factors and not solely to the ignorance of TBAs. TBAs still play an important role for many women there. Hence improvement of the formal health sector should be combined with life-saving programmes integrating TBAs in the care for the pregnant, delivering and breastfeeding mothers. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.