Role of erosion and isostasy in the Cordillera Blanca uplift: insights from Low-T thermochronology and landscape evolution modeling (northern Peru, Andes)

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Margirier, A.; Robert, X.; Braun, J.; Laurence, A.

2017-12-01

The uplift and exhumation of the highest Peruvian peaks seems closely linked to the Cordillera Blanca normal fault that delimits and shape the western flank of the Cordillera Blanca. Two models have been previously proposed to explain the occurrence of extension and the presence of this active normal fault in a compression setting but the Cordillera Blanca normal fault and the uplift and exhumation of the Cordillera Blanca remain enigmatic. Recent studies suggested an increase of exhumation rates during the Quaternary in the Cordillera Blanca and related this increase to a change in climate and erosion process (glacial erosion vs. fluvial erosion). The Cordillera Blanca granite has been significantly eroded since its emplacement (12-5 Ma) indicating a significant mass of rocks removal. Whereas it has been demonstrated recently that the effect of eroding denser rocks can contribute to an increase of uplift rate, the impact of erosion and isostasy on the increase of the Cordillera Blanca uplift rates has never been explored. Based on numerical modeling of landscape evolution we address the role of erosion and isostasy in the uplift and exhumation of the Cordillera Blanca. We performed inversions of the present-day topography, total exhumation and thermochronological data using a landscape evolution model (FastScape). Our results evidence the contribution of erosion and associated flexural rebound to the uplift of the Cordillera Blanca. Our models suggest that the erosion of the Cordillera Blanca dense intrusion since 3 Ma could also explain the Quaternary exhumation rate increase in this area. Finally, our results allow to question the previous models proposed for the formation of the Cordillera Blanca normal fault.

A new species of salamander (Bolitoglossa: Plethodontidae from the Cordillera Oriental of the Colombian Andes

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Andrés R. Acosta-Galvis

2012-01-01

Full Text Available Eight species of salamanders are recognized to Cordillera Oriental of Colombia. Here we describe a new species of the genus Bolitoglossa, named Bolitoglossa guaneae sp. nov. The highest number of species of this genus is found in the cloud forests located in the western flank of the Cordillera Oriental.

Invasion of a rocky intertidal shore by the tunicate Pyura praeputialis in the Bay of Antofagasta, Chile.

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Castilla, Juan Carlos; Guiñez, Ricardo; Caro, Andrés U; Ortiz, Verónica

2004-06-08

Invasion by marine nonindigenous species (NIS) is a spread phenomenon. The tunicate Pyura praeputialis shows pronounced disjoint geographical distribution: along thousands of kilometers in wave-swept headlands on the southeastern coast of Australia, from where it appears to have originated, and exclusively along 60-70 km inside the Bay of Antofagasta, Chile. mtDNA sequences suggested that the species invaded this rocky shore recently. We used field manipulations and juvenile P. praeputialis transplant techniques to test hypotheses regarding the capacity of the tunicate to survive and grow at different sites and tidal heights inside and outside Antofagasta, and its competitive performance for primary space (inside the Bay) against the native mussel Perumytilus purpuratus. We conclude that survival and growth of P. praeputialis showed no significant differences among sites inside and outside the Bay, and suggest that the restrictive distribution of the species in Chile is caused by a specific oceanographic retention mechanism and/or its brief larval dispersal. We demonstrated that, inside the Bay, P. praeputialis outcompetes Perumytilus from the Mid-Low intertidal, constraining Perumytilus to the Upper Mid-Intertidal, modifying the local pattern of intertidal zonation. We show that predation on P. praeputialis juveniles by starfish and snails constitutes a regulatory mechanism for the setting of its low intertidal limit. Major ecological impacts caused by NIS invasions to rocky shores by aggressive primary space users may result in negative aspects, but also may contribute to biodiversity enhancement. We call attention to the need for increment manipulations and testing of ecological hypotheses regarding marine NIS.

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

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Gianni A. Romani Chocce

2006-10-01

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

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

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

2016-04-01

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

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

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MAURICIO CERDA

2001-12-01

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

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

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Alvaro Rodrigo Martel

2004-01-01

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

Analysis of the dynamic of underground water in Agua Verde, Quebrada de Taltal, region of Antofagasta, Chile

International Nuclear Information System (INIS)

Rojas, Luis; Lillo, Adrian; Salazar, Carlos; Aguirre, Evelyn

2003-01-01

The extreme aridity and geological situation in northern. Chile requires an exhaustive investigation on water resources for supporting rational usage. The Direccion General de Aguas and Comision Chilena de Energia Nuclear have performed studies in arid zones in northern Chile using isotopic and hydrochemical tools. In Quebrada de Taltal's basin, located in one of the must arid arid zones of Chile (Segunda Region de Antofagasta), was studies groundwater dynamics and recharge process from a geochemical approach in terms of water quality, temperature and isotopic composition ( 2 H, 18 O, 3 H, 14 C). The recharge generated above 3000 m a.s.t has a slow dynamics and involve little flow (author)

The Downstream Fate of Glacial Runoff and Groundwater in the Cordillera Blanca, Peru

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McKenzie, J. M.; Gordon, R.; Chavez, D.; Maharaj, L.; Baraer, M.; Mark, B. G.; Lautz, L. K.

2013-12-01

Rapid glacier recession in the Cordillera Blanca, Peru, is raising concerns about current and future water resources for the inhabitants of the Rio Santa watershed. Glacier meltwater buffers stream discharge throughout the range, reducing the variability of annual runoff and maintaining stream flows during the dry season. Groundwater is also an important component of dry season runoff as it can contribute as much as 50-70% to outflow in some Rio Santa tributaries. A better understanding of groundwater dynamics in high elevation watersheds is needed, including quantification of recharge, subsurface processes, and available storage. We present the results from recent groundwater studies in the Cordillera Blanca where numerous investigative techniques have been used, including ground penetrating radar, hydraulic conductivity measurements, tracer tests, and hydrochemical mixing models. Our research focuses primarily on the low-relief pampa valley floors across which glacial-melt derived rivers flow. Across the Cordillera, these valley systems cover approximately 65 km2 and are comprised of unconsolidated glacial, talus, and lacustrine deposits and wetlands. The valleys commonly have buried, permeable, talus aquifers that are overlain by relatively impermeable, glaciolacustrine deposits. Glaciofluvial outwash deposits also act as aquifers (hydraulic conductivity of 10-4 m/s). The travel time of water stored in these systems is generally less than 3-4 years and the maximum observed dry season groundwater velocity is 60 cm/day. While groundwater represents an important component of dry season water resources source of water in the Cordillera Blanca, it is also potentially vulnerable to climate change including changes in the precipitation regime and decrease in glacially derived recharge.

Within plate seismicity analysis in the segment between the high Cordillera and the Precordillera of northern Mendoza (Southern Central Andes

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Julián Olivar

2018-01-01

Full Text Available Crustal seismicity in northwestern Mendoza Province in Argentina, corresponding to the transition zone between the Chilean-Pampean flat subduction zone (26.5–33.5°S and the Southern Central Andes normal subduction zone to the south, is studied in order to i identify its relationship with the mapped structure, ii determine deformational mechanisms and iii constrain the geometry of the fold and thrust belt in the lower crust. Through this, we aim to determine which are the structures that contribute to Andean construction, east of the Frontal Cordillera in Argentina and at the western Principal Cordillera in Chile. Data from a temporary local seismic network are reprocessed in order to achieve a precise location of hypocenters and, whenever possible, to build focal mechanisms. Results are interpreted and compared with previous seismic studies and structural models. Analyzed seismicity is grouped around the eastern front of Frontal Cordillera, with hypocenters mainly at depths of 25–40 km. Contrastingly, earthquakes in the Principal Cordillera to the west are located at the axial Andean sector and Chilean slope, with depths shallower than 15 km. Obtained focal mechanisms indicate mainly strike-slip displacements, left lateral at Frontal Cordillera and right lateral at Principal Cordillera. Based on these observations, new possible structural models are proposed, where seismogenic sources could be either associated with inherited basement structures from the Cuyania-Chilenia suture; or correspond to deep-blind thrusts linked with a deeper-than-previously-assumed decollement that could be shared between Frontal Cordillera and western Precordillera. This deeper decollement would coincide in turn with the one determined from receiver function analysis for the eastern Sierras Pampeanas in previous works, potentially implying a common decollement all through the fold and thrust belt configuration. Apart from this, a new interpretation of

Cordillera Blanca: glaciares en la historia

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1995-01-01

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

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

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Liliana M. Manzi

2008-05-01

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

The asymmetric evolution of the Colombian Eastern Cordillera. Tectonic inheritance or climatic forcing? New evidence from thermochronology and sedimentology

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Ramirez-Arias, Juan Carlos; Mora, Andrés; Rubiano, Jorge; Duddy, Ian; Parra, Mauricio; Moreno, Nestor; Stockli, Daniel; Casallas, Wilson

2012-11-01

New thermochronological data, facies, paleocurrents and provenance allow us to refine the chronology of deformation in the central segment of the Colombian Eastern Cordillera. Based on a new extensive AFT dataset, we document the spatial evolution of active deformation, from the axial zone of the Eastern Cordillera at about 50 Ma in to active growth of the frontal thin skinned structures in Late Miocene time. Paleocurrents allow us to push backwards into the Middle to Early Late-Miocene the emergence of the easternmost frontal thrust; whereas careful assessment of exposure gates tied to AFT data enable to refine the unroofing history for Eocene to Miocene times. Based on that, we produced a kinematically restored cross section with higher resolution than previous assessments. Using these datasets, we compare the evolution of the central segment of the Eastern Cordillera in this region with the evolution of adjacent areas in the context of climatic forcing of orogenic evolution. We find that in this region and, in the Eastern Cordillera in general, tectonic inheritance and transpression exert an initial dominant control on the initial orogen asymmetry, which is later enhanced due to an orographically-focused erosion. We therefore suggest that it is not climate alone the factor controlling orogenic asymmetry in the Eastern Cordillera of Colombia.

Lichenometry in the Cordillera Blanca, Peru: “Little Ice Age” moraine chronology

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Solomina, Olga; Jomelli, Vincent; Kaser, Georg; Ames, Alcides; Berger, Bernhard; Pouyaud, Bernard

2007-10-01

This paper is a comparison and compilation of lichenometric and geomorphic studies performed by two independent teams in the Cordillera Blanca, Peru, in 1996 and 2002 on 66 "Little Ice Age" moraines of 14 glaciers. Using eleven new control points, we recalibrated the initial rapid growth phase of the previously established Rhizocarpon subgenus Rhizocarpon growth curve. This curve was then used to estimate the age of "Little Ice Age" moraines. The time of deposition of the most prominent and numerous terminal and lateral moraines on the Pacific-facing side of the Cordillera Blanca (between AD 1590 and AD 1720) corresponds to the coldest and wettest phase in the tropical Andes as revealed by ice-core data. Less prominent advances occurred between AD 1780 and 1880.

Metallogenic events in the Coastal Cordillera of Copiapo region, northern Chile (26-28o S)

International Nuclear Information System (INIS)

Diaz, A.; Vivallo, W

2001-01-01

The metallogenic province of the Coastal Cordillera in the Copiapo region is characterized by Cu, Cu-Au,Cu-Fe-Au, Fe, Ag and Au deposits. The ore deposits are ranging in ages between Middle to Late Jurassic (1) and Early Cretaceous (2). Results of a geochronology program for ore deposits in this metallogenic province, in addition to existing geochronological control of the ore deposits host rocks (mainly intrusive) allowed to define four different Metallogenic Epochs which could be extended to other zones in the Coastal Cordillera (au)

Petrography and geochemistry of magmatic units from the western cordillera of Ecuador (0 deg. 30'S): tectonic implications

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Cosma, L.; Mamberti, M.; Gabriele, P.; Desmet, A.

1998-01-01

The cost and western Cordillera of Ecuador are made of accreted oceanic terranes, separated from from the continental margin by a suture zone containing tectonic slices of mafic rocks. The western Cordillera contains three distinct magmatic units. Ultramafic and mafic cumulates from the suture zone (San Juan slice) represent likely the plutonic roots of oceanic plateau basalts. The mafic cumulates are LREE(depleted and Ta and Pb enriched (primitive mantle). Their Nd and Pb isotopic compositions suggest that they derived from an enriched OIB type mantle source. Pre-Coniacian arc-tholeiites present flat REE patterns, low Pb and Th contents, and high ξ Nd(T=100Ma) (+7.5 to + 7.9) which are indicative of their derivation from a mantle source. These arc-tholeiites developed likely in an intra-oceanic setting. The Eocene calc-alkaline lavas differ from the arc-tholeiites because they are LREE-enriched and have lower ξ Nd(T=50Ma) ratios. Their high Pb and Th contents are probably related to crustal assimilation during the magmas ascent. Their Pb isotopic compositions support involvement of subducted pelagic sediments in their genesis. These lavas represent likely the remnants of a continental calc-alkaline magmatic arc. The continental-arc setting of the Eocene lavas demonstrates that these volcanic rocks postdate the accretion of the western Cordillera, upon which they rest unconformably. Therefore, the accretion of the western Cordillera may have occurred in late Paleocene times, as for part of the oceanic terranes of coastal Ecuador. Nevertheless, the occurrence of a collisional event during late Santonian-early Campanian times is strongly suggested by: the arrival of detrital quartz on oceanic series of the western Cordillera by Campanian-Maastrichtian times, a regional unconformity locally dates early Campanian, the arc-jump observed on coastal Ecuador in Santonian times, and finally a thermal event recognised in the eastern Cordillera around 85-80 Ma. (authors)

A new terrestrial snail species (Gastropoda: Bulimulidae from the Región de Antofagasta, northern Chile

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Juan Francisco Araya

2017-07-01

Full Text Available A new species of Scutalus Albers, 1850 (Gastropoda: Bulimulidae, Scutalus chango sp. n., is described from a coastal area of northern Chile. Empty shells of this new species were found buried in sand and under boulders and rocks in the foothills of the Chilean Coastal Range at Paposo, Región de Antofagasta. This new species is distinguished from all other Chilean terrestrial snails by its slender shell with a flared and reflected aperture, and by the presence of a columellar fold. This is the first record of Scutalus in Chile, and the southernmost record for this endemic South American bulimulid genus. The presence of this species in Paposo highlights the need for further research and for conservation guidelines in coastal areas of northern Chile, which have comparatively high levels of biodiversity and endemism.

40Ar/39Ar dates in the Central Cordillera of Colombia: Evidence for an upper triassic regional tecnomagmatic event

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Vinasco, C.J.; Cordani, U.G.; Vasconcelos, P

2001-01-01

The Coastal, Western, Central and the Eastern Cordilleras constitute four independent mountain ranges in the Northern Andes. The Coastal and Western Cordillera comprises allochthonous oceanic sequences of basic volcanic rocks and marine sediments of Cenozoic and Upper Cretaceous age (Aspden et al., 1987). The so-called Central Cordillera Polymetamorphic Complex (Restrepo and Toussaint, 1982), made up the pre-Mesozoic Central Cordillera basement, consists of low through high-grade metamorphic rocks intruded by Meso-Cenozoic batholiths. The Eastern Cordillera is a polydeformed continental mountain range consisting of Precambrian and Paleozoic metamorphic and igneous rocks overlain by Paleozoic to Mesozoic sedimentary covers. The northern part of the Central Cordillera has been described as a suspect terrain affected by several tectonometamorphic episodes. The most important of them have been always considered those related to the Hercynian orogeny, in Devonian and Carboniferous times, and those occurring at the beginning of the Andean Cycle in the Cretaceous (Restrepo and Toussaint, 1982). A possible Lower Paleozoic and even Precambrian age for the basement of the terrain has also been proposed. Although some indications of a Permo-Triassic event are already available, this period was not considered as of great importance for the geologic evolution of the region. The available radiometric dates in the 200-250 Ma interval, for the Central Cordillera, are as follows: 1. One K-Ar whole rock age for a Granulite of 251±21 Ma. (Restrepo et al, 1991) of the El Retiro group SE of Medellin. However, a K-Ar biotite age of 110±10 Ma. (Toussaint et al., 1978) was obtained for a migmatite rock associated with the same group. 2. A Sm/Nd garnet and whole rock age of 226±17 Ma in rocks associated to granulites, SE of Medellin, interpreted as metamorphic ages (Correa and Martins, 2001). 3. K-Ar biotite dates for the Puqui metamorphic complex, occurring north of Medellin, ranging

(U-Th)/He thermochronometric constraints on the late Miocene-Pliocene northern Cordillera Real, tectonic development of the northern Cordillera Real, tectonic development of the Interandean Depression, the Spikings, Ecuador.

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Spikings, R. A.; Crowhurst, P. V.

2004-12-01

The low sensitivity of apatite fission track (AFT) thermochronometry at temperatures less than ˜60 °C suggests that AFT data sets from the Andean Cordilleras may have frequently failed to identify specific periods after 9 Ma when cooling rates were high. Forward modeling of (U-Th)/He apatite age data obtained from the juxtaposed Paleozoic-Mesozoic Alao, Loja, and Salado terranes in the northern Cordillera Real, Ecuador, has improved the resolution of previous AFT thermal histories for the past 9 My. The Alao and Loja terranes form a coherent, structural block that resided at temperatures greater than 70-80 °C until ˜3.3-2.8 Ma and then cooled rapidly to less than 40 °C at rates of >15 °C/My. Intraterrane variations in the cooling and exhumation histories in the Salado terrane suggest that nonterrane-bounding faults played a significant role during its Pliocene-Recent evolution. The Salado terrane preserves an older history that reveals elevated cooling rates during 22-19 and 18-15 Ma. Subsequently, the terrane cooled rapidly from greater than 90 °C to less than 40 °C during 11-8 and 5.5-3.5 Ma at rates of >8 °C/My. Vertical reactivation of the Llanganates fault, which separates the Salado and Loja terranes, during the Pliocene-Recent coincides with the main stages of formation of the juxtaposed Interandean Depression, which provides further constraints on the growth phases of the depression and the Cordillera.

Early Tertiary Exhumation, Erosion, and Sedimentation in the Central Andes, NW Argentina

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Carrapa, B.; Decelles, P. G.; Gerhels, G.; Mortimer, E.; Strecker, M. R.

2006-12-01

-Oligocene ages (ca. 37-32 Ma) are also present, suggesting a similar volcanogenic origin for these grains and time-stratigraphic equivalence to the Geste Formation. The upper conglomeratic part of this formation records western sources mainly composed of volcanic, granitic and quartzitic rocks derived from the proto-Eastern Cordillera. Detrital apatite fission track (AFT) data from the Geste Formation document strong Paleocene and early Eocene signals suggesting active exhumation of western sources. This corroborates AFT data from the Cordillera Domeyko (northern Chile) to the west and the proto-Eastern Cordillera to the east of the study area documenting cooling and exhumation at this time. Combined, these data indicate active Paleocene to Eocene deformation, exhumation, erosion, and sedimentation within the region that corresponds to the present-day Puna Plateau and the Eastern Cordillera.

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

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Lynch John D.

1996-11-01

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

Geochemistry of the Puna Austral and Cordillera Oriental basement

International Nuclear Information System (INIS)

Becchio, Raul; Lucassen, Friedrich; Franz, Gerhard; Kasemann, Simone

1998-01-01

Major and trace elements, rare earths, and 143 Nd/ 147 Nd and, 147 Sm/ 144 Nd isotope ratios have been determined in the Puna Austral and Cordillera Oriental basement. The basement is formed by high temperature amphibolite facies rocks ranulites (750-550 degrees C) and green schists. They are represented by schists, paragneiss, orthogneiss, migmatites, few metabasites, marbles and chalcosilicatic banks. Hypotheses on the formation and evolution of the basement are presented

Denudation rates and tectonic geomorphology of the Spanish Betic Cordillera

Science.gov (United States)

Bellin, N.; Vanacker, V.; Kubik, P. W.

2014-03-01

The tectonic control on landscape morphology and long-term denudation is largely documented for settings with high uplift rates. Relatively little is known about the rates of geomorphic response in areas of low tectonic uplift. Here, we evaluate spatial variations in denudation of the Spanish Betic Cordillera based on cosmogenic 10Be-derived denudation rates. Denudation rates are compared to published data on rock uplift and exhumation of the Betic Cordillera to evaluate steady-state topography. The spatial patterns of catchment-wide denudation rates (n=20) are then analysed together with topographic metrics of hillslope and channel morphology. Catchments draining the Betic ranges have relatively low denudation rates (64±54 mm kyr), but also show large variation as they range from 14 to 246 mm kyr-1. Catchment-wide denudation is linearly proportional to the mean hillslope gradient and local relief. Despite large spatial variation in denudation, the magnitude and spatial pattern of denudation rates are generally consistent with longer-term local uplift rates derived from elevated marine deposits, fission-track measurements and vertical fault slip rates. This might be indicative of a steady-state topography where rock uplift is balanced by denudation.

The Vegetation of the Páramos of the Colombian Cordillera Oriental

NARCIS (Netherlands)

Cleef, A.M.

1981-01-01

A phytosociological survey based on methods of the Zürich-Montpellier School was carried out in the páramo vegetation of the Cordillera Oriental, Colombia. The study area covers about 10,000 and comprises the páramo between the Nevado de Sumapaz (3°55'N, 4250 m), the Sierra Nevada del Cocuy (6°25'N,

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

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Alejandra M. Elías

2013-07-01

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

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

Science.gov (United States)

Salzmann, N.; Huggel, C.; Rohrer, M.; Silverio, W.; Mark, B. G.; Burns, P.; Portocarrero, C.

2013-01-01

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

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

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N. Salzmann

2013-01-01

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

Determination of the levels of trace elements in ten years old children from Antofagasta city, Chile by neutron activation analysis

International Nuclear Information System (INIS)

Gras, N.; Munoz, A.L.; Jamett J, A.; Pena C, L.; Santander M, M.

1988-01-01

The levels of trace elements in scalp hair of ten years old children of Antofagasta city were determined. For this study, the city was divided in convenient areas. Comparisons between levels of concentrations considering residential areas, sex, values obtained for children of Santiago, and the ranges given in the literature were established. Fifty samples of hair were analyzed by instrumental neutron activation analisis. The elements selected were: As, Br, Co, Cr, Cu, Fe, Hg, K, Na. Sb, and Zn. The effectiveness of wash procedure before irradiation was studied. Ten samples were taken with sufficient amount of hair and each was divided into two, only one of them was washed and both were analyzed. The levels of concentrations were compared. (author)

An assessment of global climate model-simulated climate for the western cordillera of Canada (1961-90)

Science.gov (United States)

Bonsal, Barrie R.; Prowse, Terry D.; Pietroniro, Alain

2003-12-01

Climate change is projected to significantly affect future hydrologic processes over many regions of the world. This is of particular importance for alpine systems that provide critical water supplies to lower-elevation regions. The western cordillera of Canada is a prime example where changes to temperature and precipitation could have profound hydro-climatic impacts not only for the cordillera itself, but also for downstream river systems and the drought-prone Canadian Prairies. At present, impact researchers primarily rely on global climate models (GCMs) for future climate projections. The main objective of this study is to assess several GCMs in their ability to simulate the magnitude and spatial variability of current (1961-90) temperature and precipitation over the western cordillera of Canada. In addition, several gridded data sets of observed climate for the study region are evaluated.Results reveal a close correspondence among the four gridded data sets of observed climate, particularly for temperature. There is, however, considerable variability regarding the various GCM simulations of this observed climate. The British, Canadian, German, Australian, and US GFDL models are superior at simulating the magnitude and spatial variability of mean temperature. The Japanese GCM is of intermediate ability, and the US NCAR model is least representative of temperature in this region. Nearly all the models substantially overestimate the magnitude of total precipitation, both annually and on a seasonal basis. An exception involves the British (Hadley) model, which best represents the observed magnitude and spatial variability of precipitation. This study improves our understanding regarding the accuracy of GCM climate simulations over the western cordillera of Canada. The findings may assist in producing more reliable future scenarios of hydro-climatic conditions over various regions of the country. Copyright

Glacial lake outburst floods in the area of Huarás, Cordillera Blanca, Peru

Czech Academy of Sciences Publication Activity Database

Vilímek, V.; Zapata, M. L.; Klimeš, Jan

2005-01-01

Roč. 39, - (2005), s. 115-124 ISSN 0081-6434 Grant - others:GA MŠk(CZ) LA 157 Institutional research plan: CEZ:AV0Z30460519 Keywords : GLOFs * Cordillera Blanca * Peru Subject RIV: DC - Siesmology, Volcanology, Earth Structure

Lithospheric Structure across the Alaskan Cordillera from Surface Waves and Receiver Functions

Science.gov (United States)

Ward, K. M.; Lin, F. C.

2017-12-01

The long awaited Transportable Array (TA) deployment in Alaska and western Canada is nearing its final deployment stage. With only one more deployment season, most of the TA station locations have been occupied and begun providing data. These TA stations combined with upgraded existing locations have provided enough high-quality data to begin investigating the crustal and upper mantle structure across the entire Alaskan Cordillera. From a tectonic standpoint, many interesting questions remain unanswered. For example, how does the transition from oceanic-oceanic subduction to continental-oceanic normal subduction to continental-oceanic "flat-slab" subduction to strike-slip conservative plate motion affect the deformation/uplift of the overriding plate and mantle geodynamic characteristics? How does the long and completed terrene accretion process partition stress/strain in the crust? On more local scales, are there any significant mid-crustal magmatic systems as observed in other sections of the American Cordillera, and if so, what is there role in uplift and crustal deformation? Our approach to investigating these questions is though surface wave imaging from ambient noise and earthquake generated sources along with Rayleigh wave ellipticity paired with Ps receiver functions. Our preliminary tomography results agree with previous studies but expand the spatial coverage showing additional detail. Our ellipticity results show a heterogeneous but spatially consistent anisotropic shallow crust. Although the complete TA data set has not yet been collected, we have jointly inverted surface waves with receiver functions for a 3-D shear-wave velocity model across the entire Alaskan Cordillera. Key features of our velocity model include a high-velocity feature in the upper mantle associated with the subducting Pacific plate that extends north of the seismicity used to contour the geometry of the slab and mid-crustal low-velocity zones associated with the active volcanics in

Geochronology of Tropical Alpine Glaciations From the Cordillera Huayhuash, Peru

Science.gov (United States)

Hall, S. R.; Farber, D. L.; Rodbell, D. T.; Finkel, R. C.; Ramage, J. M.; Smith, J. A.; Mark, B. G.; Seltzer, G. O.

2004-12-01

The Cordillera Huayhuash of the Central Peruvian Andes (10.3° S, 76.9° W) is an ideal range to study regional climate signals and variations in paleo-ice volumes. Located between the Cordillera Blanca to the north and the Junin region to the south, the range trends nearly north-south with modern glaciers confined to the high peaks (>4800 m). Cross-cutting relationships, geomorphology, and correlation with surface exposure dated moraines in the nearby Cordillera Blanca suggest the region preserves a rich record of tropical glaciation. In order to determine the glacial chronology we mapped and dated glacial features of the Jahuacocha valley (which drains the western side of the range) and two eastern drainages, the Mitococha valley, and the Carhuacocha valley. At each locality we used ASTER data, aerial photographs, and GPS to map glacial features both within main valleys and tributaries. We sampled quartz-bearing erratics on moraine crests as well as ice-polished bedrock surfaces for exposure age dating using in situ produced cosmogenic 10Be and 26Al. In the Jahuacocha valley, the greatest ice extent reached an elevation of ˜4090m and moraine crest boulders yield and age of ˜11.2 ±0.6 ka suggesting a significant late Glacial ice advance or stillstand. A younger cluster of moraines exists ˜1 km up-valley at an elevation of ˜4100m. These moraines, dated at ˜8.0 ±1.0 ka, suggest an early Holocene advance. In the Mitococha valley, a young moraine and polished bedrock dated at ˜0.2 ka and ˜11.4 ±0.4 ka respectively span the late Glacial through recent. The late Glacial features of this eastern drainage occur at an elevation of ˜4100m while the recent events occur at an elevation of ˜4380m. Our preliminary results suggest that all three valleys experienced a very similar glacial history with minor differences likely due to the variations in valley morphology. Comparing the chronology of glaciation in the Cordillaera Huayhuash with that in regions to the

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

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Racquel Tan Chua-Barcelo

2014-05-01

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

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

Science.gov (United States)

Pérez Lancellotti, Gino; Ziede Bize, Marcela

2017-10-01

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

Total arsenic, lead, cadmium, copper, and zinc in some salt rivers in the northern Andes of Antofagasta, Chile.

Science.gov (United States)

Queirolo, F; Stegen, S; Mondaca, J; Cortés, R; Rojas, R; Contreras, C; Munoz, L; Schwuger, M J; Ostapczuk, P

2000-06-08

The pre-Andes water in the region of Antofagasta is the main drinking and irrigation water source for approximately 3000 Atacameña (indigenous) people. The concentration for soluble elements (filtration in field through a 0.45-microm filter) was: Cd < 0.1 ng/ml; Pb < 0.5 ng/ml; and Zn and Cu between 1 and 10 ng/ml. In particulate material the concentrations were: for Cd < 0.1 ng/ml; for Pb < 0.3 ng/ml; and for Zn and Cu less than 1 ng/ml. The total content of these elements is far below the international recommendations (WHO) and the national standards (N. Ch. 1333 mod. 1987 and 409-1 of 1984). On the other hand, in some rivers a very high arsenic concentration was found (up to 3000 ng/ml) which exceed more than 50 times the national standard. In order to verify the analytical results, inter-laboratory and comparison with different determination methods have been done.

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

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García, Silvia P.

2002-05-01

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

JURASSIC PALEONTOLOGICAL HERITAGE OF MURCIA (BETIC CORDILLERA, SOUTH-EASTERN SPAIN

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GREGORIO ROMERO

2004-03-01

Full Text Available Jurassic rocks of the External and Internal Zones of the Betic Cordillera are widespread in the province of Murcia. Four areas are considered of special interest for stratigraphical and paleontological analysis: a Sierra Quípar and b Sierras Lúgar-Corque (External Subbetic, c Sierra Ricote (Median Subbetic and d Sierra Espuña (Malaguide Complex. The first two contain Jurassic sections including Sinemurian-Tithonian deposits, and major stratigraphic discontinuities, containing significant cephalopod concentrations of taphonomic and taxonomic interest, occuring in the Lower-Upper Pliensbachian, Lower/Middle Jurassic and Middle/Upper Jurassic boundaries. These areas are also relevant for biostratigraphical analysis of the Middle-Upper Jurassic interval. In the Sierra de Ricote, the Mahoma section is of especial interest for the study of Lías/Dogger transition. Casa Chimeneas section constitutes the best Subbetic site for the analysis of the Lower/Upper Bajocian boundary. In the La Bermeja-Casas de Vite area, the Bajocian-Tithonian interval is well-represented, including a parastratotype of the Radiolarite Jarropa Formation. Finally, the Malvariche section in Sierra Espuña represents the best Jurassic succession of Internal Zones of the Betic Cordillera and could be considered as a reference section for this Betic Domain. In this paper a heritage evaluation has been carried out for these classical jurassic sections with the object of protecting these sites according to the legal framework prevailing in the province of Murcia.

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

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CRISTIAN J. PACHECO

2000-09-01

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

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

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Alejandrina Alucema

2013-12-01

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

Integrating Multiple Geophysical Methods to Quantify Alpine Groundwater- Surface Water Interactions: Cordillera Blanca, Peru

Science.gov (United States)

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

2016-12-01

Groundwater- surface water interactions in alpine catchments are often poorly understood as groundwater and hydrologic data are difficult to acquire in these remote areas. The Cordillera Blanca of Peru is a region where dry-season water supply is increasingly stressed due to the accelerated melting of glaciers throughout the range, affecting millions of people country-wide. The alpine valleys of the Cordillera Blanca have shown potential for significant groundwater storage and discharge to valley streams, which could buffer the dry-season variability of streamflow throughout the watershed as glaciers continue to recede. Known as pampas, the clay-rich, low-relief valley bottoms are interfingered with talus deposits, providing a likely pathway for groundwater recharged at the valley edges to be stored and slowly released to the stream throughout the year by springs. Multiple geophysical methods were used to determine areas of groundwater recharge and discharge as well as aquifer geometry of the pampa system. Seismic refraction tomography, vertical electrical sounding (VES), electrical resistivity tomography (ERT), and horizontal-to-vertical spectral ratio (HVSR) seismic methods were used to determine the physical properties of the unconsolidated valley sediments, the depth to saturation, and the depth to bedrock for a representative section of the Quilcayhuanca Valley in the Cordillera Blanca. Depth to saturation and lithological boundaries were constrained by comparing geophysical results to continuous records of water levels and sediment core logs from a network of seven piezometers installed to depths of up to 6 m. Preliminary results show an average depth to bedrock for the study area of 25 m, which varies spatially along with water table depths across the valley. The conceptual model of groundwater flow and storage derived from these geophysical data will be used to inform future groundwater flow models of the area, allowing for the prediction of groundwater

Empirical downscaling of atmospheric key variables above a tropical glacier surface (Cordillera Blanca, Peru)

Science.gov (United States)

Hofer, M.; Kaser, G.; Mölg, T.; Juen, I.; Wagnon, P.

2009-04-01

Glaciers in the outer tropical Cordillera Blanca (Peru, South America) are of major socio-economic importance, since glacier runoff represents the primary water source during the dry season, when little or no rainfall occurs. Due to their location at high elevations, the glaciers moreover provide important information about climate change in the tropical troposphere, where measurements are sparse. This study targets the local reconstruction of air temperature, specific humidity and wind speed above the surface of an outer tropical glacier from NCEP/NCAR reanalysis data as large scale predictors. Since a farther scope is to provide input data for process based glacier mass balance modelling, the reconstruction pursues a high temporal resolution. Hence an empirical downscaling scheme is developed, based on a few years' time series of hourly observations from automatic weather stations, located at the glacier Artesonraju and nearby moraines (Northern Cordillera Blanca). Principal component and multiple regression analyses are applied to define the appropriate spatial downscaling domain, suitable predictor variables, and the statistical transfer functions. The model performance is verified using an independent data set. The best predictors are lower tropospheric air temperature and specific humidity, at reanalysis model grid points that represent the Bolivian Altiplano, located in the South of the Cordillera Blanca. The developed downscaling model explaines a considerable portion (more than 60%) of the diurnal variance of air temperature and specific humidity at the moraine stations, and air temperature above the glacier surface. Specific humidity above the glacier surface, however, can be reconstructed well in the seasonal, but not in the required diurnal time resolution. Wind speed can only be poorly determined by the large scale predictors (r² lower than 0.3) at both sites. We assume a complex local interaction between valley and glacier wind system to be the main

Landslide and glacial lake outburst flood hazard in the Chucchún river basin, Cordillera Blanca, Peru

Czech Academy of Sciences Publication Activity Database

Klimeš, Jan; Vilímek, V.; Benešová, M.

2015-01-01

Roč. 50, č. 2 (2015), s. 173-180 ISSN 0300-5402 R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : landslide hazard * GLOFs * flood hazard * Cordillera Blanca * Peru Subject RIV: DE - Earth Magnetism, Geodesy, Geography

Potenciální nebezpečnost vybraných morénami hrazených jezer v pohoří Cordillera Blanca, Peru

OpenAIRE

Emmer, Adam

2013-01-01

Adam Emmer: Potential hazardousness of selected moraine-dammed lakes in the Cordillera Blanca, Peru ABSTRACT: This work is devided into the two parts. Firs part reviews contemporary methods of assessment of potential hazardousness for moraine-dammed lakes (eight qualitative methods and three quantitative methods). Second part has two main aims: 1) Assessment of potential hazardousness of seven selected moraine-dammed lakes in the Cordillera Blanca, and 2) Analysis of suitability of these meth...

LGM and Late Glacial glacier advances in the Cordillera Real and Cochabamba (Bolivia deduced from 10Be surface exposure dating

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H. Veit

2007-10-01

Full Text Available Surface exposure dating (SED is an innovative tool already being widely applied for moraine dating and for Late Quaternary glacier and climate reconstruction. Here we present exposure ages of 28 boulders from the Cordillera Real and the Cordillera Cochabamba, Bolivia. Our results indicate that the local Last Glacial Maximum (LGM in the Eastern Cordilleras occurred at ~22–25 ka and was thus synchronous to the global temperature minimum. We were also able to date several Late Glacial moraines to ~11–13 ka, which likely document lower temperatures and increased precipitation ("Coipasa" humid phase. Additionally, we recognize the existence of older Late Glacial moraines re-calculated to ~15 ka from published cosmogenic nuclide data. Those may coincide with the cold Heinrich 1 event in the North Atlantic region and the pronounced "Tauca" humid phase. We conclude that (i exposure ages in the tropical Andes may have been overestimated so far due to methodological uncertainties, and (ii although precipitation plays an important role for glacier mass balances in the tropical Andes, it becomes the dominant forcing for glaciation only in the drier and thus more precipitation-sensitive regions farther west and south.

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

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William E. Duellman

2007-12-01

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

El enjambre sísmico de Macas (cordillera de Cutucú)

OpenAIRE

Legrand, Denis; Baby, Patrice; Bondoux, Francis; Dorbath, Catherine; Bès de Berc, Séverine; Rivadeneira, Marco

2015-01-01

La sismicidad de la región de Macas es comparada a la sismicidad global del Ecuador. Un experimento con diez estaciones sismológicas de corto período fue realizado entre 1999 y 2000, cerca de la ciudad de Macas, en la parte sur del piedemonte subandino del Ecuador (Cordillera de Cutucú). Las ubicaciones de los terremotos registrados fueron comparadas y correlacionadas con las estructuras geológicas. Algunos eventos están alineados en una dirección NNE-SSW que corresponde a la orientación de l...

RV SONNE SO243 Cruise Report / Fahrtbericht Guayaquil, Ecuador: 05. October 2015 Antofagasta, Chile: 22. October 2015 SO243 ASTRA-OMZ: AIR SEA INTERACTION OF TRACE ELEMENTS IN OXYGEN MINIMUM ZONES

OpenAIRE

Marandino, Christa A.

2016-01-01

The ASTRA-OMZ SO243 cruise on board the R/V Sonne took place between the 5th and 22nd October 2015 from Guayaquil, Ecuador to Antofagasta, Chile. Scientists from Germany, the U.S.A, and Norway participated, spanning chemical, biological, and physical oceanography, as well as atmospheric science. The main goal of the cruise was to determine the impact of low oxygen conditions on trace element cycling and distributions, as well as to determine how air-sea exchange of trace elements is influence...

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

NARCIS (Netherlands)

Kuenen, Ph.H.

1926-01-01

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

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

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Patricio R. Araya

2017-11-01

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

Proglacial Groundwater Flux and Storage in the Cordillera Blanca, Peru

Science.gov (United States)

Chavez, D.; McKenzie, J. M.; Baraer, M.; Mark, B. G.

2012-12-01

As tropical glaciers continue to rapidly retreat in the Cordillera Blanca, Peru, dry-season water resources are becoming more dependent on groundwater baseflow. Therefore, understanding the flux and storage of proglacial groundwater is necessary to forecast how groundwater storage can offset decreasing water resources. Recent studies of the Rio Santa Watershed, which drains the western slopes of the Cordillera Blanca, have identified that groundwater is the largest contributor to outflow from many watersheds during the dry season and that the flux of groundwater is temporarily available (clay to silt sized glaciolacustrine material at each drill site. This layer was typically less than 5 m in thickness and had a low hydraulic conductivity (clay layer were water bearing units of course material (either well-sorted sand/gravel or talus deposits) with an average hydraulic conductivity of 10-5 m/s. Additionally numerous discontinuous sand lenses and localized glaciofluvial gravel deposits were observed within the clay layer. The glaciolacustrine deposits behave as confining units that were capable of generating localized artesian conditions in the coarse grain units. The occurrence of the clay units adjacent to the main stream channels suggests that the flatness of the valley floors is not the result of river meander. The coarse grained units have the potential to act as important aquifers with significant groundwater storage and flow. Our preliminary findings indicate that the course grained units are important hydrogeological conduits with the ability to buffer low flow conditions in proglacial streams during the dry season. We present a new schematic model of how groundwater moves through these important proglacial environments, providing temporal storage of glacial meltwater and precipitation.

The metamorphic basement of the Cordillera Frontal of Mendoza: New geochronologic and isotopic data

International Nuclear Information System (INIS)

Basei, Miguel; Ramos, Victor A.; Vujovich, Graciela I.; Poma, Stella

1998-01-01

The metamorphic rocks of the Cordillera Frontal exposed in the Cordon del Portillo, Mendoza were examined by Rb/Sr geochronology and Nd/Sm isotopic analysis. The Rb/Sr data defined a Devonian age for the last metamorphic episode, similar to the previous K/Ar and Ar/Ar ages obtained in this region and western Precordillera. The isotopic analysis identified three sets of model ages: 1.- The oldest corresponds to a set of meta sedimentary rocks with a model age of 1,400 to 1,700 Ma; 2.- A monzogranodiorite with a model age of 1,000 Ma; and 3.- Metabasites with model ages between 577 and 330 Ma. These rocks are interpreted as 1.- A typical Grenvillian derived basement; 2.- Late Paleozoic granitoids derived from a different Proterozoic basement; and 3.- Some Eopaleozoic metabasites tectonically inter fingered with the Grenvillian basement. These new data are coherent with the existence of a Laurentia derived terrane, Chilenia, that was separated by oceanic rocks from the basement of Pre cordillera during Eopaleozoic times. This last basement known as the Cuyania terrane, was also derived from Laurentia. (author)

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

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Jorge Guillermo Ortiz

2012-11-01

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

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

NARCIS (Netherlands)

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

2015-01-01

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

Contrasting Modern and 10Be- derived erosion rates for the Southern Betic Cordillera, Spain

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Bellin, N.; Vanacker, V.; Kubik, P.

2012-04-01

In Europe, Southeast Spain was identified as one of the regions with major treat of desertification in the context of future land use and climate change. During the last years, significant progress has been made to understand spatial patterns of modern erosion rates in these semi-arid degraded environments. Numerous European projects have contributed to the collection of modern erosion data at different spatial scales for Southeast Spain. However, these data are rarely analysed in the context of long-term changes in vegetation, climate and human occupation. In this paper, we present Modern and Holocene denudation rates for small river basins (1 to 10 km2) located in the Spanish Betic Cordillera. Long-term erosion data were derived from cosmogenic nuclide analyses of river-borne sediment. Modern erosion data were quantified through analysis of sediment deposition volumes behind check dams, and represent average erosion rates over the last 10 to 40 years. Modern erosion rates are surprisingly low (mean erosion rate = 0.048 mm y-1; n=36). They indicate that the steep, sparsely vegetated hillslopes in the Betic Cordillera cannot directly be associated with high erosion rates. 10Be -derived erosion rates integrate over the last 37500 to 3500 years, and are roughly of the same magnitude. They range from 0.013 to 0.243 mm y-1 (mean denudation rate = 0.062 mm y-1 ± 0.054; n=20). Our data suggest that the modern erosion rates are similar to the long-term erosion rates in this area. This result is in contrast with the numerous reports on human-accelerated modern erosion rates for Southeast Spain. Interestingly, our new data on long-term erosion rates show a clear spatial pattern, with higher erosion rates in the Sierra Cabrera and lower erosion rates in Sierra de las Estancias, and Sierra Torrecilla. Preliminary geomorphometric analyses suggest that the spatial variation that we observe in long-term erosion rates is related to the gradient in uplift rates of the Betic

Late Quaternary geomorphic history of a glacial landscape - new sedimentary and chronological data from the Cordillera de Cochabamba (Bolivia)

Science.gov (United States)

May, J.-H.; Preusser, F.; Zech, R.; Ilgner, J.; Veit, H.

2009-04-01

Throughout the Central Andes, glacial landscapes have long been used for the reconstruction of Late Quaternary glaciations and landscape evolution. Much work has focused on the Andes in Peru, Chile and the Bolivian Altiplano, whereas relatively little data has been published on glaciation history in the eastern Andean ranges and slopes. Even less is known with regard to the postglacial evolution of these glacial landscapes. In the Cordillera de Cochabamba (Bolivia), local maximum advances probably peaked around 20-25 ka BP and were followed by significant readvances between ~12-16 ka BP. This generally points to temperature controlled maximum glacial advances along the humid eastern slopes of the Central Andes, which is supported by glacier-climate-modelling studies. However, most studies include only marginal information with regard to the complex geomorphic and sedimentary situation in the Cordillera de Cochabamba. Furthermore, the chronological results are afflicted with several methodological uncertainties inherent to surface exposure dating and call for application of alternative, independent age dating methods. Therefore this study aims at i) documenting and interpreting the complex glacial geomorphology of the Huara Loma valley in the Cordillera de Cochabamba (Bolivia), ii) analyzing the involved units of glacial sediments, and iii) improving the chronological framework by applying optically stimulated luminescence (OSL) and radiocarbon dating (14C). For this purpose, geomorphic mapping was combined with field documentation of sedimentary profiles. The involved sediments were subject to geochemical and mineralogical analysis in order to deduce information on their erosional and weathering histories. In addition, the interpretation of OSL ages from glacial and proglacial sediments integrated several methodological procedures with regard to sample preparation and statistical analysis of the measurements in order to increase the degree of confidence. These

The Vegetation of the Páramos of the Colombian Cordillera Oriental

OpenAIRE

Cleef, A.M.

1981-01-01

A phytosociological survey based on methods of the Zürich-Montpellier School was carried out in the páramo vegetation of the Cordillera Oriental, Colombia. The study area covers about 10,000 and comprises the páramo between the Nevado de Sumapaz (3°55'N, 4250 m), the Sierra Nevada del Cocuy (6°25'N, 5493 m) and the Páramo del Almorzadero (7°N, 4375 m). The páramo vegetation was studied along various altitudinal transects from the upper forest line (3000-3500 m) up to the lower limit of the sn...

Evidence for Multiple Late Quaternary Glaciations in the Southernmost Cordillera Blanca, Peru

Science.gov (United States)

Smith, J. A.; Rodbell, D. T.; Ramage, J. M.

2007-12-01

Surface-exposure dating with in-situ-produced cosmogenic isotopes has provided the basis for a growing framework of glacial chronologies in the tropical Andes. In the Peruvian Andes, long chronologies (>400 ka) with relatively small local last glacial maximum (LLGM) advances have been reported for the central Cordillera Blanca (ca. 9°30'S) and Junin Plain (11°00'S), whereas preliminary data suggest a shorter record (<40 ka) in the intervening Cordillera Huayhuash (10°15'S). These seemingly contradictory findings raise several questions: Was the LLGM a relatively minor event in the Peruvian Andes, far exceeded by bigger, older advances? Which combination of geographic and geomorphic factors increases the likelihood that evidence of older advances will be preserved? With these questions in mind, we sought a site with both high peaks and a high-altitude plateau. The glaciated Nevado Jeulla Rajo massif (10°00'S, 77°16'W, peaks ca. 5600 masl) marks the southern end of the Cordillera Blanca and the Callejon de Huaylas valley in the central Peruvian Andes. The Conococha Plain (ca. 4050 masl) borders the western side of the massif. Large lateral moraines extend onto the Conococha Plain from the west-facing valleys and multiple moraine loops lie upvalley, closer to active ice margins. Surface-exposure dating (10Be) indicates that the largest lateral moraines from Jeullesh Valley are compound features deposited during the LLGM (ca. 30 ka) and a late-glacial readvance (ca. 16 ka). The LLGM/late-glacial moraines cross-cut an older pair of lateral moraines (ca. 70 ka) that may provide evidence for a smaller advance during marine isotope stage 4. Although the LLGM/late-glacial moraines are impressively large (ca. 150 m high), they do not represent the maximum ice extent in the region. Fluvial outwash deposits beyond the termini of the moraines on the Conococha Plain are underlain by lodgement till that is up to 20 m thick and extends ca. 6 km across the width of the Plain

Recent glacier retreat and climate trends in Cordillera Huaytapallana, Peru

Science.gov (United States)

López-Moreno, J. I.; Fontaneda, S.; Bazo, J.; Revuelto, J.; Azorin-Molina, C.; Valero-Garcés, B.; Morán-Tejeda, E.; Vicente-Serrano, S. M.; Zubieta, R.; Alejo-Cochachín, J.

2014-01-01

We analyzed 19 annual Landsat Thematic Mapper images from 1984 to 2011 to determine changes of the glaciated surface and snow line elevation in six mountain areas of the Cordillera Huaytapallana range in Peru. In contrast to other Peruvian mountains, glacier retreat in these mountains has been poorly documented, even though this is a heavily glaciated area. These glaciers are the main source of water for the surrounding lowlands, and melting of these glaciers has triggered several outburst floods. During the 28-year study period, there was a 55% decrease in the surface covered by glaciers and the snowline moved upward in different regions by 93 to 157 m. Moreover, several new lakes formed in the recently deglaciated areas. There was an increase in precipitation during the wet season (October-April) over the 28-year study period. The significant increase in maximum temperatures may be related to the significant glacier retreat in the study area. There were significant differences in the wet season temperatures during El Niño (warmer) and La Niña (colder) years. Although La Niña years were generally more humid than El Niño years, these differences were not statistically significant. Thus, glaciers tended to retreat at a high rate during El Niño years, but tended to be stable or increase during La Niña years, although there were some notable deviations from this general pattern. Climate simulations for 2021 to 2050, based on the most optimistic assumptions of greenhouse gas concentrations, forecast a continuation of climate warming at the same rate as documented here. Such changes in temperature might lead to a critical situation for the glaciers of the Cordillera Huaytapallana, and may significantly impact the water resources, ecology, and natural hazards of the surrounding areas.

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

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Wigmore, O.; Mark, B. G.

2015-12-01

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

Lithofacies control in detrital zircon provenance studies: Insights from the Cretaceous Methow basin, southern Canadian Cordillera

Science.gov (United States)

DeGraaff-Surpless, K.; Mahoney, J.B.; Wooden, J.L.; McWilliams, M.O.

2003-01-01

High-frequency sampling for detrital zircon analysis can provide a detailed record of fine-scale basin evolution by revealing the temporal and spatial variability of detrital zircon ages within clastic sedimentary successions. This investigation employed detailed sampling of two sedimentary successions in the Methow/Methow-Tyaughton basin of the southern Canadian Cordillera to characterize the heterogeneity of detrital zircon signatures within single lithofacies and assess the applicability of detrital zircon analysis in distinguishing fine-scale provenance changes not apparent in lithologic analysis of the strata. The Methow/Methow-Tyaughton basin contains two distinct stratigraphic sequences of middle Albian to Santonian clastic sedimentary rocks: submarine-fan deposits of the Harts Pass Formation/Jackass Mountain Group and fluvial deposits of the Winthrop Formation. Although both stratigraphic sequences displayed consistent ranges in detrital zircon ages on a broad scale, detailed sampling within each succession revealed heterogeneity in the detrital zircon age distributions that was systematic and predictable in the turbidite succession but unpredictable in the fluvial succession. These results suggest that a high-density sampling approach permits interpretation of finescale changes within a lithologically uniform turbiditic sedimentary succession, but heterogeneity within fluvial systems may be too large and unpredictable to permit accurate fine-scale characterization of the evolution of source regions. The robust composite detrital zircon age signature developed for these two successions permits comparison of the Methow/Methow-Tyaughton basin age signature with known plutonic source-rock ages from major plutonic belts throughout the Cretaceous North American margin. The Methow/Methow-Tyaughton basin detrital zircon age signature matches best with source regions in the southern Canadian Cordillera, requiring that the basin developed in close proximity to the

Active Deformation of the Northern Cordillera Observed with GPS

Science.gov (United States)

Elliott, J.; Jiang, Y.; Leonard, L. J.; Hyndman, R. D.; Freymueller, J.; Mazzotti, S.

2017-12-01

The Northern Cordillera, which encompasses western Canada and eastern Alaska, is a complex tectonic puzzle. Past terrane accretions, the present collision of the Yakutat block, large-scale plate motions, and past and present glacier change have created a tectonic landscape that includes a major transform system, most of the highest peaks in North America, and far-flung ongoing distributed deformation. We present an updated GPS velocity field as well as a new integrated tectonic block model for the region. The style of deformation varies through the region. Surrounding the Yakutat collision, the model includes a number of small blocks that indicate rotations to the east, north, and west as material moves away from the collisional front. These small blocks also show evidence of internal deformation. Farther from the collisional front, blocks are larger and appear to behave more rigidly. In the south, northwestward motion resulting in a prominent band of coastal shear extends from Vancouver Island to Glacier Bay. In the Arctic, small southeastward motions in Alaska transition to easterly motion in Canada that extends to the Mackenize Mountains near the Cordillera-craton boundary. A number of faults and fault systems accommodate relative Pacific-North America plate motion in the region, although the significant majority is along the Fairweather-Queen Charlotte transform system and the St. Elias fold-and-thrust belt. Along the Fairweather-Queen Charlotte system, the motion is dominantly dextral with increasing oblique transpression to the south corresponding to a change in margin trend. At the northern end of the transform system, motion is distributed onto multiple faults. Roughly 75% of the Fairweather motion is transferred west into the St. Elias fold-and-thrust belt, which accommodates 30 mm/yr of convergence. The remaining 25% is transferred north towards the dextral Denali-Totschunda system. The eastern Denali fault presently plays a minor role in accommodating

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

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Alejandrina Alucema

2015-02-01

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

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

Science.gov (United States)

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

2015-04-01

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

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

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Restrepo Carla

1992-09-01

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

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

Science.gov (United States)

Emmer, Adam

2017-12-01

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

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

Science.gov (United States)

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

2017-11-01

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

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

Czech Academy of Sciences Publication Activity Database

Ruiz Cruz, M. D.; Novák, Jiří Karel

2003-01-01

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

Superposition of tectonic structures leading elongated intramontane basin: the Alhabia basin (Internal Zones, Betic Cordillera)

Science.gov (United States)

Martínez-Martos, Manuel; Galindo-Zaldivar, Jesús; Martínez-Moreno, Francisco José; Calvo-Rayo, Raquel; Sanz de Galdeano, Carlos

2017-10-01

The relief of the Betic Cordillera was formed since the late Serravallian inducing the development of intramontane basins. The Alhabia basin, situated in the central part of the Internal Zones, is located at the intersection of the Alpujarran Corridor, the Tabernas basin, both trending E-W, and the NW-SE oriented Gádor-Almería basin. The geometry of the basin has been constrained by new gravity data. The basin is limited to the North by the Sierra de Filabres and Sierra Nevada antiforms that started to develop in Serravallian times under N-S shortening and to the south by Sierra Alhamilla and Sierra de Gádor antiforms. Plate convergence in the region rotated counter-clockwise in Tortonian times favouring the formation of E-W dextral faults. In this setting, NE-SW extension, orthogonal to the shortening direction, was accommodated by normal faults on the SW edge of Sierra Alhamilla. The Alhabia basin shows a cross-shaped depocentre in the zone of synform and fault intersection. This field example serves to constrain recent counter-clockwise stress rotation during the latest stages of Neogene-Quaternary basin evolution in the Betic Cordillera Internal Zones and underlines the importance of studying the basins' deep structure and its relation with the tectonic structures interactions.

Geochronology and Equilibrium Line Altitudes of LLGM through Holocene Glaciations from the Tropical Cordillera Huayhuash, Peru

Science.gov (United States)

Hall, S. R.; Ramage, J. M.; Rodbell, D. T.; Finkel, R. C.; Smith, J. A.; Mark, B. G.; Farber, D. L.

2006-12-01

Geomorphologic relationships and cosmogenic 10Be ages from the Central Peruvian Andes reveal a rich record of glaciations from at least the late Holocene, Late Glacial, Last Local Glacial Maximum (LLGM), and older more extensive glaciations - dated between 50ka and 440ka in both the Cordillera Blanca, to the north and the Junin Region to the south. The Cordillera Huayhuash (10.3°S, 76.9°W) is located between these two well-studied regions. The spine of the range trends nearly north-south and contains a substantial east-west spur which together can be used to evaluate the spatial variation in paleo-ELAs. The range is thus a key location to study changes in ice extent and equilibrium line altitudes (ELAs) between the LLGM and modern periods. Modern glaciers are confined to altitudes >4800 m and the present (1997) ELA is 4800- 5100m. In order to determine the paleo-ice positions of glaciers in different valleys we have developed a new chronology from cosmogenic 10Be ages of moraine boulder and 14C basal bog core ages. Through field mapping of glacial features, analysis of satellite imagery, digital elevation models (DEMs), and geochronology, we have delineated the ice limits associated with the LLGM, Late Glacial, and Late Holocene advances. Ages in the three valleys we have studied cluster at ~29ka, ~13ka, and ~9ka and overall we have identified surfaces with ages that range from 39.9±1.4ka to 0.2ka±0.05ka. Based on these data, we have mapped the extent of the correlative paleo-glaciers in these three drainages and extracted the modern hypsometry for each paleo-glacier from the DEMs. From this data set, we have generated paleo- ELAs using a range of methods: Toe-to-Headwall-Altitude Ratio (THAR), the Accumulation Area Ratio (AAR), and Accumulation Area Balance Ratio (AABR). For each of the LLGM, Late Glacial and Holocene stages, we have calculated both: (1) the temperature depression assuming no moisture variations, and (2) the potential relative moisture

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

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Marcela Cantillánez

2011-11-01

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

Geochronology, geochemistry and tectonic evolution of the Western and Central cordilleras of Colombia

Science.gov (United States)

Villagómez, Diego; Spikings, Richard; Magna, Tomas; Kammer, Andreas; Winkler, Wilfried; Beltrán, Alejandro

2011-08-01

Autochthonous rocks of the pre-Cretaceous continental margin of NW South America (the Tahami Terrane) are juxtaposed against a series of para-autochthonous rock units that assembled during the Early Cretaceous. Allochthonous, oceanic crust of the Caribbean Large Igneous Province collided with and accreted onto the margin during the Late Cretaceous. We present the first regional-scale dataset of zircon U-Pb LA-ICP-MS ages for intrusive and metamorphic rocks of the autochthonous Tahami Terrane, Early Cretaceous igneous para-autochthonous rocks and accreted oceanic crust. The U-Pb zircon data are complemented by multiphase 40Ar/ 39Ar crystallization and cooling ages. The geochronological data are combined with whole rock major oxide, trace element and REE data acquired from the same units to constrain the tectonic origin of the rock units and terranes exposed in the Western Cordillera, Cauca-Patía Valley and the Central Cordillera of Colombia. The Tahami Terrane includes lower Paleozoic orthogneisses (~ 440 Ma) that may have erupted during the active margin stage of the Rheic Ocean. Basement gneisses were intruded by Permian, continental arc granites during the final assembly of Pangea. Triassic sedimentary rocks were subsequently deposited in rift basins and partially melted during high-T metamorphism associated with rifting of western Pangea during 240-220 Ma. Continental arc magmatism during 180-145 Ma is preserved along the whole length of the Central Cordillera and was followed by an Early Cretaceous out-board step of the arc axis and the inception of the Quebradagrande Arc that fringed the continental margin. Back-stepping of the arc axis may have been caused by the collision of buoyant seamounts, which were coeval with plateau rocks exposed in the Nicoya Peninsular of Costa Rica. Rapid westward drift of South America closed the Quebradagrande basin in the late Aptian and caused medium-high P-T metamorphic rocks of the Arquía Complex to exhume and obduct onto

Preliminary isotopic data from some amphibolites of the metamorphic basement of the Colombian Central Cordillera

International Nuclear Information System (INIS)

Correa M, Ana Maria; Martens K, Uwe; Ordonez C, Oswaldo; Pimentel, Marcio M; Restrepo A, Jorge Julian

2001-01-01

Various amphibolite bodies are exposed in the Antioquia Department, Colombia, mainly around the cities of Medellin and El Retiro. Two types of amphibolites occur in the study area; the first one is considered as part of an ophiolite complex and the second one correspond to amphibolites associated to metasediments from the basement of the Colombian Central Cordillera. The present work refers to these last ones. The relationships between amphibolite bodies and other lythological units are the following ones: Intercalation of amphibolites layers with metasediments in the unit migmatites and granulites of El Retiro. The Medellin amphibolites are conformably overlaid by the paragneisses of Las Penas. The granodiorite body represented by the Antioquian Batolith is intrusive in the metamorphic rocks and the Medellin Dunites unit is in thrust fault contact with Medellin amphibolites. These amphibolites have been studied by Botero (1963), Gonzalez (1976 and 1980), Restrepo and Toussaint (1984), Ardila (1986), Restrepo (1986), Rendon (1999) and, Correa and Martens (2000). Available radiometric ages on the amphibolites come from former works by Restrepo y Toussaint (1978), Restrepo et al. (1991) that presented K-Ar ages in amphiboles and a Rb-Sr isochron which yielded a Cretaceous age that they interpreted as a metamorphic age. This work presents new evidences, obtained from field work, petrography, rock geochemistry and specially the first isotopic data on these amphibolites from the Central Cordillera Metamorphic Basement (au)

Landslides in moraines as triggers of glacial lake outburst floods: example from Palcacocha Lake (Cordillera Blanca, Peru)

Czech Academy of Sciences Publication Activity Database

Klimeš, Jan; Novotný, J.; Novotná, I.; Urries de, B.J.; Vilímek, V.; Emmer, Adam; Strozzi, T.; Kusák, Michal; Rapre, A.C.; Hartvich, Filip; Frey, H.

2016-01-01

Roč. 13, č. 6 (2016), s. 1461-1477 ISSN 1612-510X R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 ; RVO:67179843 Keywords : landslides * moraines * glacial lakes * slope stability calculation * glacial lake outburst floods * impact wave models * Cordillera Blanca Subject RIV: DE - Earth Magnetism, Geodesy, Geography; DE - Earth Magnetism, Geodesy, Geography (UEK-B) Impact factor: 3.657, year: 2016

Multi-temporal InSAR for Deformation Monitoring of the Granada and Padul Faults and the Surrounding Area (Betic Cordillera, Southern Spain)

NARCIS (Netherlands)

Sousa, J.J.; Ruiz, A.M.; Hooper, A.J.; Hanssen, R.F.; Perski, Z.; Bastos, L.C.; Gil, A.J.; Galindo-Zaldivar, J.; Sanz de Galdeano, C.; Alfaro, P.; Garrido, M.S.; Armenteros, J.A.; Gimenez, E.; Aviles, M.

2014-01-01

The quantification of low rate active tectonic structures is a major target of geodetic and geological studies to improve the knowledge of seismic hazards. The central Betic Cordillera (southern Spain) is affected by moderately active tectonic structures and seismicity. Part of this seismic activity

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

Czech Academy of Sciences Publication Activity Database

Novotný, J.; Klimeš, Jan

2014-01-01

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

Reinterpretation of the formation of the "crooked moraine" of the debris-covered Hatunraju Glacier (Cordillera Blanca, Perú)

Science.gov (United States)

Iturrizaga, L.

2012-04-01

The Hatunraju Glacier (9°00'S/70°40'W) is located in the Parón valley in the northern part of the Cordillera Blanca. The almost 4 km long and steeply inclined glacier flows down from the Huandoy-N-Side (6395 m) into the Parón valley to an elevation of 4250 m a.s.l.. The extremely narrow glacier is in its entire ablation area heavily debris-covered. It is one of the few glaciers, which dam with its debris-mantled glacier tongue a main river in this mountain range. In this case the Hatunraju glacier produces the largest glacier-dammed lake in the Cordillera Blanca, the Laguna Parón. In some other aspects, this glacier proves to be distinct from the majority of the glaciers in the Cordillera Blanca: It is flowing on an almost up to 250 m high moraine pedestal ("moraine-dammed raised bed glacier") and the glacier makes a bend of almost 90° when entering into the main valley. The present paper focuses in particular on the last point: the formation of the so called "crooked moraine". It has been explained by Lliboutry (1977) as a result of a glacier lake outburst and the subsequent destruction of the latero-frontal moraine. The later process supposed to be the trigger of the abrupt change in the flow direction of the lower part of the glacier. Recent investigations suggest an alternative genesis of the crooked moraine considering the distinct phases of the glaciation history of the Parón valley. The here proposed formation pattern is also paradigmatic for other crooked debris-covered glaciers, especially in High Asia. Comparative examples will be provided from the Karakoram and Himalayas. The research work on the Hatunraju Glacier is part of a project on the glacial geomorphology in the Tropical Andes financed by the Alexander von Humboldt-Foundation.

Clasificación de yeso mediante imágenes ASTER en la Cordillera Principal Mendocina

OpenAIRE

José F Mescua

2010-01-01

Se presenta una metodología para obtener el mapa de distribución de yeso con imágenes satelitales ASTER. Se utilizaron imágenes con nivel de procesamiento ASTERL3A correspondientes a dos áreas de la Cordillera Principal mendocina. La estratigrafía de las áreas de estudio se encuentra compuesta por una espesa sucesión sedimentaria mesozoica, volcanitas cenozoicas y depósitos cuaternarios. Dentro de los depósitos mesozoicos se encuentra la Formación Auquilco, integrada por yeso y anhidrita. El ...

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

NARCIS (Netherlands)

Velásquez-R., C.A.; Hooghiemstra, H.

2013-01-01

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

Glacier Changes in the Cordillera Blanca, Peru, Derived From SPOT5 Imagery, GIS and Field- Based Measurements

Science.gov (United States)

Racoviteanu, A.; Arnaud, Y.; Williams, M. W.; Singh Khalsa, S.

2007-12-01

There is urgency in deriving an extensive dataset for deriving glacier changes within the Cordillera Blanca, Peru, in a cost-effective and timely manner. Rapid glacial retreat during the last decades in this area poses a threat for water resources, hydroelectric power and local traditions. While there is some information on decadal changes in glacier extents, there still remains a paucity of mass balance measurements and glacier parameters such as hypsometry, size distribution and termini elevations. Here we investigate decadal changes in glacier parameters for Cordillera Blanca of Peru using data from Système Probatoire d'Observation de la Terre (SPOT) sensor, an old glacier inventory from 1970 aerial photography, field-based mass balance measurements and meteorological observations. Here we focus on: constructing a geospatial glacier inventory from 2003 SPOT scenes; mass balance estimations using remote sensing and field data; frequency distribution of glacier area; changes in termini elevations; hypsometry changes over time; glacier topography (slope, aspect, length/width ratio); AAR vs. mass balance for Artesonraju and Yanamarey benchmark glaciers; precipitation and temperature trends in the region. Over the last 25 years, mean temperatures increases of 0.09 deg.C/yr were greater at lower elevation than the 0.01 deg.C/yr at higher elevations, with little change in precipitation. Comparison of the new SPOT-based glacier inventory with the 1970 inventory shows that glaciers in Cordillera Blanca retreated at a rate of 0.6% per year over the last three decades, with no significant differences in the rate of area loss between E and W side. At lower elevations there is an upward shift of glacier termini along with a decrease in glacier area. Small glaciers are losing more area than large glaciers. Based on the relationship between specific mass balance (bn) and accumulation area ratio (AAR) for the two benchmark glaciers, we predicted a steady-state equilibrium line

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

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GEMITA PIZARRO

2002-03-01

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

A cosmogenic 10Be chronology for the local last glacial maximum and termination in the Cordillera Oriental, southern Peruvian Andes: Implications for the tropical role in global climate

Science.gov (United States)

Bromley, Gordon R. M.; Schaefer, Joerg M.; Hall, Brenda L.; Rademaker, Kurt M.; Putnam, Aaron E.; Todd, Claire E.; Hegland, Matthew; Winckler, Gisela; Jackson, Margaret S.; Strand, Peter D.

2016-09-01

Resolving patterns of tropical climate variability during and since the last glacial maximum (LGM) is fundamental to assessing the role of the tropics in global change, both on ice-age and sub-millennial timescales. Here, we present a10Be moraine chronology from the Cordillera Carabaya (14.3°S), a sub-range of the Cordillera Oriental in southern Peru, covering the LGM and the first half of the last glacial termination. Additionally, we recalculate existing 10Be ages using a new tropical high-altitude production rate in order to put our record into broader spatial context. Our results indicate that glaciers deposited a series of moraines during marine isotope stage 2, broadly synchronous with global glacier maxima, but that maximum glacier extent may have occurred prior to stage 2. Thereafter, atmospheric warming drove widespread deglaciation of the Cordillera Carabaya. A subsequent glacier resurgence culminated at ∼16,100 yrs, followed by a second period of glacier recession. Together, the observed deglaciation corresponds to Heinrich Stadial 1 (HS1: ∼18,000-14,600 yrs), during which pluvial lakes on the adjacent Peruvian-Bolivian altiplano rose to their highest levels of the late Pleistocene as a consequence of southward displacement of the inter-tropical convergence zone and intensification of the South American summer monsoon. Deglaciation in the Cordillera Carabaya also coincided with the retreat of higher-latitude mountain glaciers in the Southern Hemisphere. Our findings suggest that HS1 was characterised by atmospheric warming and indicate that deglaciation of the southern Peruvian Andes was driven by rising temperatures, despite increased precipitation. Recalculated 10Be data from other tropical Andean sites support this model. Finally, we suggest that the broadly uniform response during the LGM and termination of the glaciers examined here involved equatorial Pacific sea-surface temperature anomalies and propose a framework for testing the viability

Active faulting in the central Betic Cordillera (Spain): Palaeoseismological constraint of the surface-rupturing history of the Baza Fault (Central Betic Cordillera, Iberian Peninsula)

Science.gov (United States)

Castro, J.; Martin-Rojas, I.; Medina-Cascales, I.; García-Tortosa, F. J.; Alfaro, P.; Insua-Arévalo, J. M.

2018-06-01

This paper on the Baza Fault provides the first palaeoseismic data from trenches in the central sector of the Betic Cordillera (S Spain), one of the most tectonically active areas of the Iberian Peninsula. With the palaeoseismological data we constructed time-stratigraphic OxCal models that yield probability density functions (PDFs) of individual palaeoseismic event timing. We analysed PDF overlap to quantitatively correlate the walls and site events into a single earthquake chronology. We assembled a surface-rupturing history of the Baza Fault for the last ca. 45,000 years. We postulated six alternative surface rupturing histories including 8-9 fault-wide earthquakes. We calculated fault-wide earthquake recurrence intervals using Monte Carlo. This analysis yielded a 4750-5150 yr recurrence interval. Finally, compared our results with the results from empirical relationships. Our results will provide a basis for future analyses of more of other active normal faults in this region. Moreover, our results will be essential for improving earthquake-probability assessments in Spain, where palaeoseismic data are scarce.

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

Science.gov (United States)

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

2015-04-01

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

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

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Jay M Savage

2009-06-01

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

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

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Ana Almendáriz

2014-01-01

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

Evidence of contrasting low-grade metamorphic conditons from clay mineral assablages in Triassic Alpujárride-Maláguide transtional units in the Betic Cordilleras, Spain

Czech Academy of Sciences Publication Activity Database

Ruiz Cruz, M. D.; Franco, F.; Sanz de Galdeano, C.; Novák, Jiří Karel

2006-01-01

Roč. 41, 2 (2006), s. 621-638 ISSN 0009-8558 Institutional research plan: CEZ:AV0Z30130516 Keywords : low-grade metamorphism * clay minerals * Betic Cordilleras Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.974, year: 2006

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

Science.gov (United States)

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

2014-10-01

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

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

Science.gov (United States)

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

2015-02-01

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

(Plio-)Pleistocene alluvial-lacustrine basin infill evolution in a strike-slip active zone (Northern Andes, Western-Central Cordilleras, Colombia)

OpenAIRE

SUTER, F.; NEUWERTH, R.; GORIN, G.; GUZMÁN, C.

2009-01-01

The (Plio)-Pleistocene Zarzal Formation was deposited in the Cauca Depression and Quindío-Risaralda Basin between the Western and Central Cordilleras (Northern Andes). This area is structurally located on the transcurrent Romeral Fault System (RFS). Because of the interaction between the Nazca plate and the Chocó-Panamá block (an active indenter), the RFS strike-slip component changes direction around the study zone (dextral in the south, senestral in the north). Zarzal sediments are the olde...

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

OpenAIRE

Jay M Savage; Federico Bolaños

2009-01-01

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

El rol de las comunidades y organizaciones indígenas en la conformación y manejo del área natural Cordillera del Cóndor, dentro del marco del Plan Binacional de Paz de Conservación Ecuador-Perú.

OpenAIRE

Saavedra Limo, Juan Pablo

2014-01-01

La presente investigación intentará analizar el Plan de Paz y Conservación Binacional en la Cordillera del Cóndor, Ecuador - Perú (PCBCC, 1998 - 2008), dentro de un proceso de política pública y su relación con propuestas políticas desde las poblaciones Shuar, Wampis y Awajun de la Cordillera del Cóndor, en torno a la conservación y el control de sus territorios.

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

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Fernando Javier Santa Cecilia Mateos

2015-01-01

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

Small-scale convection at a continental back-arc to craton transition: Application to the southern Canadian Cordillera

Science.gov (United States)

Hardebol, N. J.; Pysklywec, R. N.; Stephenson, R.

2012-01-01

A step in the depth of the lithosphere base, associated with lateral variations in the upper mantle temperature structure, can trigger mantle flow that is referred to as edge-driven convection. This paper aims at outlining the implications of such edge-driven flow at a lateral temperature transition from a hot and thin to a cold and thick lithosphere of a continental back-arc. This configuration finds application in the southern Canadian Cordillera, where a hot and thin back-arc is adjacent to the cold and thick North American Craton. A series of geodynamical models tested the thermodynamical behavior of the lithosphere and upper mantle induced by a step in lithosphere thickness. The mantle flow patterns, thickness and heat flow evolution of the lithosphere, and surface topography are examined. We find that the lateral temperature transition shifts cratonward due to the vigorous edge-driven mantle flow that erodes the craton edge, unless the craton has a distinct high viscosity mantle lithosphere. The mantle lithosphere viscosity structure determines the impact of edge-driven flow on crustal deformation and surface heat flow; a dry olivine rheology for the craton prevents the edge from migrating and supports a persistent surface heat flow contrast. These phenomena are well illustrated at the transition from the hot Canadian Cordillera to craton that is supported by a rheological change and that coincides with a lateral change in surface heat flow. Fast seismic wave velocities observed in the upper mantle cratonward of the step can be explained as downwellings induced by the edge-driven flow.

Transición y peligrosidad climática en la Cordillera Central Oriental: la comarca Tiermes-Caracena

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Ortega Villazán, Mª Teresa

2008-06-01

Full Text Available This paper characterizes climate in the easternmost portion of the Cordillera Central region in the Iberian Peninsula, more particularly its northern piedmont –the district called Tiermes-Caracena. A detailed analysis of its several pluviometric and thermal variables underlines this district’s unique features, as well as a number of traits which provide it with elements of contrast and diversity. Outstanding processes of its climate are the imprint of geographic relief, the different patterns of climatic transition depending on the several directions, and the extreme behaviour of some climatic variables in this inland mountain area. All observations are reflected in the climatic cartography that is included in this paper.

Se realiza una caracterización del clima del sector más oriental de la Cordillera Central, centrado principalmente en el estudio de su piedemonte septentrional, el correspondiente a la comarca de Tiermes-Caracena. Con el análisis detallado de sus diferentes variables térmicas y pluviométricas se resaltan los caracteres que más la singularizan, así como los elementos de contraste y diversidad. Se destacan como procesos más significativos en su clima la impronta que introduce el relieve, la transición climática que se marca según direcciones y el comportamiento extremo de algunas variables climáticas de este espacio de montaña interior. Todo queda reflejado en la cartografía climática que se acompaña.

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

Energy Technology Data Exchange (ETDEWEB)

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

2010-04-15

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

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

International Nuclear Information System (INIS)

Di Pasquale, G.; Impagliazzo, S.; Lubritto, C.; Marziano, M.; Passariello, I.; Ermolli, E. Russo

2010-01-01

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

Rhyolitic calderas and centers clustered within the active andesitic belt of Ecuador's Eastern Cordillera

Energy Technology Data Exchange (ETDEWEB)

Mothes, Patricia A; Hall, Minard L [Instituto Geofisico, Escuela Politecnica Nacional, Quito (Ecuador)], E-mail: pmothes@igepn.edu.ec

2008-10-01

In the Ecuadorian volcanic arc a cluster of scattered rhyolitic and dacitic centers within the mainly andesitic Eastern Cordillera includes large caldera structures (Chalupas, Chacana, Cosanga) as well as smaller edifices, built upon the Paleozoic-Mesozoic metamorphic basement. At the Chacana caldera magmatism dates from 2.7 Ma to historic times. These centers erupted enormous ash flows and thick pumice lapilli falls that covered the InterAndean Valley near Quito. The role of the 50-70 km-thick crust with a notable negative gravity anomaly appears to be related to the generation of this highly silicic magmatism occurring along the crest of the Andes in the NVZ.

New records of Kinosternon leucostomum postinguinale (Duméril and Bibron, 1851 from the Central Cordillera of Colombia

Directory of Open Access Journals (Sweden)

Julián Arango-L

2018-03-01

Full Text Available We record the presence of Kinosternon leucostomum postinguinale (DUMÉRIL and BIBRON, 1851 populations in the department of Quindío, Central Cordillera of Colombia. Despite the turtle is found in the neighboring departments of Tolima and Valle del Cauca, this is the first evidence of its distribution on this locality. We present biological and ecological records of individuals in the lower and middle area of La Vieja basin inhabiting small tributaries and ponds between pastures. Currently it is unknown whether the species was introduced or ignored until now.

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

OpenAIRE

Carolina Garcia; Michel Hermelin

2004-01-01

Este trabajo es una estimación preliminar del tiempo necesario para generar la espesa capa de saprolito que caracteriza el perfil de meteorización actual de un batolito cuarzodiorítico cretácico que aflora en altiplanos de la Cordillera Central de Colombia, entre 5º50' y 7º00' de latitud Norte y 74º50' y 75º35' de longitud Oeste y a alturas entre 750 y 2700 m.Se utilizan datos obtenidos previamente mediante el análisis de la composición química de las aguas superficiales d...

Climate in the Western Cordillera of the Central Andes over the last 4300 years

Science.gov (United States)

Engel, Zbyněk; Skrzypek, Grzegorz; Chuman, Tomáš; Šefrna, Luděk; Mihaljevič, Martin

2014-09-01

The Distichia peat core obtained in the Carhuasanta valley near Nevado Mismi, Cordillera Chila, provides information on climatic and environmental conditions over the last ˜4300 years. The relative changes in the stable carbon isotope composition of plant remains preserved in the core reflect major temperature fluctuations in the Western Cordillera of the southern Peruvian Andes. These temperature variations can be additionally linked with the changes in precipitation patterns by analysing C% and C/N ratio in the core. Relatively warm and moist conditions prevailed from 4280 to 3040 cal. yrs BP (BC 2330-1090) with a short colder dry episode around 3850 cal. yrs BP (BC 1900). The most prominent climate changes recorded in the peat occurred between 3040 and 2750 cal. yrs BP (BC 1090-800) when the initial warming turned to a rapid cooling to temperatures at least 2 °C lower than the mean for the Late Holocene. Initially drier conditions within this event turned to a short wet phase after 2780 cal. yrs BP (BC 830) when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes matching the timing of the global climate event around 2.8 cal. ka BP. Climatic conditions in the study area became relatively dry and stable after the event for about 800 years. Highly variable temperatures and humidity prevailed during the last 2000 years when an extended warm and relatively humid period occurred between 640 and 155 cal. yrs BP (AD 1310-1795) followed by predominantly colder and drier conditions. The established δ13C peat record represents the first continuous proxy for the temperature in the southern Peruvian Andes dated by the AMS 14C. Distichia peat is wide spread in the Andes and the proposed approach can be applied elsewhere in high altitudes, where no other traditional climate proxies are available.

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

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Lynch John Douglas

1999-11-01

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

Isotopic dating of the post-Alpine Neogene volcanism in the Betic Cordilleras, southern Spain

Energy Technology Data Exchange (ETDEWEB)

Nobel, F A; Rondeel, H E [Amsterdam Univ. (Netherlands). Geologisch Inst.; Andriessen, P A.M.; Hebeda, E H; Priem, H N.A. [Laboratorium voor Isotopen-Geologie, Amsterdam (Netherlands)

1981-06-01

The post-Alpine lamproitic volcanism in the Prebetic of the External Zone of the Betic Cordilleras of southern Spain is dated at 7.6-7.2 Ma by the K-Ar data from two richterites, two sanidines, a phlogopite and a whole-rock, and the fission-track analysis of an apatite. Biotite from a lava of the rhyolitic-dacitic suite in the post-orogenic Vera basin of the Internal Zone produces the same age. Phlogopite from a lamproitic (veritic) subvolcanic body in the Vera basin yields an age of about 8.6 Ma; as lavas belonging to the veritic suite reportedly overlie Late Messinian sediments, pointing to an age of less than about 5 Ma, this type of volcanism in the Vera basin must have been active over several million years.

Quantifying Quaternary Deformation in the Eastern Cordillera of the Colombian Andes Using Cosmogenic Nuclide Geochronology and Fluvial Geomorphology

Science.gov (United States)

Dalman, E.; Taylor, M. H.; Veloza-fajardo, G.; Mora, A.

2014-12-01

Northwest South America is actively deforming through the interaction between the Nazca, South American, and Caribbean plates. Though the Colombian Andes are well studied, much uncertainty remains in the rate of Quaternary deformation along the east directed frontal thrust faults hundreds of kilometers in board from the subduction zones. The eastern foothills of the Eastern Cordillera (EC) preserve deformed landforms, allowing us to quantify incision rates. Using 10Be in-situ terrestrial cosmogenic nuclide (TCN) geochronology, we dated 2 deformed fluvial terraces in the hanging wall of the Guaicaramo thrust fault. From the 10Be concentration and terrace profile relative to local base level, we calculated incision rates. We present a reconstructed slip history of the Guaicaramo thrust fault and its Quaternary slip rate. Furthermore, to quantify the regional Quaternary deformation, we look at the fluvial response to tectonic uplift. Approximately 20 streams along the eastern foothills of the Eastern Cordillera (EC) were studied using a digital elevation model (DEM). From the DEM, longitudinal profiles were created and normalized channel steepness (Ksn) values calculated from plots of drainage area vs. slope. Knickpoints in the longitudinal profiles can record transient perturbations or differential uplift. Calculated Ksn values indicate that the EC is experiencing high rates of uplift, with the highest mean Ksn values occurring in the Cocuy region. Mean channel steepness values along strike of the foothills are related to increasing uplift rates from south to north. In contrast, we suggest that high channel steepness values in the south appear to be controlled by high rates of annual precipitation.

Taxonomía y biogeografía de cuatro especies de Psectrascelis (Coleoptera: Tenebrionidae de la Precordillera y Cordillera de los Andes en Mendoza, Argentina

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Gustavo E. FLORES

2005-01-01

Full Text Available El género neotropical Psectrascelis Solier (Pimeliinae: Nycteliini comprende 75 especies que se distribuyen desde el sur de Perú hasta el sur de Argentina y Chile. En este aporte se revisan las cuatro especies de Psectrascelis que habitan en el noroeste de la provincia de Mendoza (Argentina, en los cordones montañosos de la Precordillera y Cordillera de los Andes: P. deplanata (Lacordaire, 1830, P. vestita (Lacordaire, 1830, P. mamillonea (Lacordaire, 1830 y P. semistrigosa Fairmaire, 1903. Se proveen redescripciones con nuevos caracteres morfológicos, fotografías de adultos y de los pronotos, e ilustraciones de genitalia masculinos. Se consigna la distribución geográfica y rangos altitudinales para cada especie, estableciendo las provincias biogeográficas que habitan. Se presenta una discusión acerca de los patrones de distribución de las especies de Psectrascelis y de otros artrópodos epigeos que habitan en los cordones montañosos de la Precordillera y Cordillera de los Andes.

A new moss salamander, genus Nototriton (Caudata: Plethodontidae), from the Cordillera de Talamanca, in the Costa Rica-Panama border region.

Science.gov (United States)

Arias, Erick; Kubicki, Brian

2018-01-07

A new salamander belonging to the genus Nototriton, subgenus Nototriton, is described from the Caribbean slopes of the southeastern Cordillera de Talamanca in Costa Rica, within Parque Internacional La Amistad, at an elevation ca. 1500 m a.s.l. This new taxon is distinguished from its congeners by its morphological characteristics and by its differentiation in DNA sequences of the 16S rRNA, cytochrome oxidase subunit I (COI), and cytochrome b mitochondrial genes. This new species represents the southernmost extension known for the genus Nototriton.

The organic matter of the Potosi basin (Cordillera Oriental, Bolivia) during the Upper Cretaceous-Lower tertiary: stratigraphic and palaeogeographic data

Energy Technology Data Exchange (ETDEWEB)

Blanc-Valleron, M.M.; Rouchy, J.M. (Centre National de la Recherche Scientifique (CNRS), 75 - Paris (France)); Schuler, M.; Rauscher, R. (Strasbourg-1 Univ., 67 (France)); Camoin, G. (Aix-Marseille-1 Univ., 13 - Marseille (France))

1994-12-01

Palynological and Rock-Eval pyrolysis studies of the Chaunaca and El Molino Fm (Santonian to Thanetian, Cordillera Oriental, Bolivia) indicate that some facies have economic significance as potential oil source rocks. The occurrence of Pediastrum and Azolla testify a lacustrine environment. In the Upper Molino, the environmental interpretation of an almost monospecific association of dinocysts is discussed. The presence of Apectodinium quinquelatum indicates that the age of the upper part of the Upper El Molino Fm is likely to be Upper Thanetian. (authors). 22 refs., 5 figs.

Empirical-statistical downscaling of reanalysis data to high-resolution air temperature and specific humidity above a glacier surface (Cordillera Blanca, Peru)

Science.gov (United States)

Hofer, Marlis; MöLg, Thomas; Marzeion, Ben; Kaser, Georg

2010-06-01

Recently initiated observation networks in the Cordillera Blanca (Peru) provide temporally high-resolution, yet short-term, atmospheric data. The aim of this study is to extend the existing time series into the past. We present an empirical-statistical downscaling (ESD) model that links 6-hourly National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) reanalysis data to air temperature and specific humidity, measured at the tropical glacier Artesonraju (northern Cordillera Blanca). The ESD modeling procedure includes combined empirical orthogonal function and multiple regression analyses and a double cross-validation scheme for model evaluation. Apart from the selection of predictor fields, the modeling procedure is automated and does not include subjective choices. We assess the ESD model sensitivity to the predictor choice using both single-field and mixed-field predictors. Statistical transfer functions are derived individually for different months and times of day. The forecast skill largely depends on month and time of day, ranging from 0 to 0.8. The mixed-field predictors perform better than the single-field predictors. The ESD model shows added value, at all time scales, against simpler reference models (e.g., the direct use of reanalysis grid point values). The ESD model forecast 1960-2008 clearly reflects interannual variability related to the El Niño/Southern Oscillation but is sensitive to the chosen predictor type.

Opening of the Gulf of Guayaquil: quantifying the motion from the trench to the Andean Cordillera

Science.gov (United States)

Santana, E.; Dumont, J. F.; Vilema, W.; Pedoja, K.

2003-04-01

The Gulf of Guayaquil is a complex pull-apart opened at the south tip of the North Andean Block. The Guayaquil-Caracas Megashear (i.e. Dolores-Guayaquil Megashear) which bounds the North Andean Block to the east crosses the Western Andean Cordillera along the Pallatanga fault, and joins southwestward the Ecuadorian trench. According to paleogeographic data the Gulf of Guayaquil began to open about 9 Ma ago, which is evidenced now by about 100 km offset of the Early Neogene Progresso and Loja basins. A lesser post orogenic offset of about 60 km is observed along the Pallatanga fault, coherent with the offset of the piedmont of the Western Andean Cordillera. The discrepancy suggests a partition of the deformation at the south tip of the North Andean Block, part of the motion being accommodated by other small faults north of the Pallatanga fault zone and resulting in a pull apart motion and subsidence of the Daule-Babahoyo basin. The main curve of the Tallara Arc described by the trend of the trench from north Peru to north Ecuador shows a significant anomaly in front of the Gulf of Guayaquil. A 60 to 70 km minimum right hand deviation of the curve is observed, displayed in three segments delimited by faults. Neotectonic studies in the Santa Clara and Puná Islands located in the Gulf of Guayaquil show a regional E-W shortening during the Pleistocene, characterised by right lateral motion along the Zambapala Cordillera in Puná. Offset of river drainage and morphostructures in South Puná gives evidence of 3 km dextral offset which post-date marine terraces with an estimated age of M.I.S. 9 or 11, giving mean offset rates of 9 mm/y or 6.8 mm/y respectively. The conclusion underlines the following points: (1) These data suggest that the offset rate inside the Gulf of Guayaquil during the Late Quaternary is lower than the mean rate observed since 9 Ma. The apparent slow down may be due to the partition of the deformation of the Gulf of Guayaquil towards the Guayas

The structural style of foot wall shortcuts along the eastern foothills of the Colombian eastern cordillera. Differences with other inversion related structures

International Nuclear Information System (INIS)

Mora, Andres; Parra, Mauricio

2008-01-01

For the first time we show geological evidence of unambiguously documented foot wall shortcuts adjacent to the trace of inverted master normal faults, in the Eastern Cordillera of Colombia. The Eastern Cordillera is an orogen whose width and location are traced by a Mesozoic Graben. However, few structures related with the Graben have been documented up to the date. In this study we propose the Ariari-Guatiquia region as a type location for a unique observation of foot wall shortcuts. The master normal faults in the Ariari-Guatiquia region, and documented in this manuscript, were active during the Lower Cretaceous, partially inverted during the Andean orogenesis (since the Oligocene at least) and active still nowadays. In the hanging wall basins of those master normal faults, like the Servita fault, all the Cretaceous syn-rift sequence has been deposited and maximum paleo-temperatures in the lowermost Cretaceous rocks are higher than those for the Zircon FT partial annealing zone (250 Celsius degrade; 23,15 K). In contraction, the inverted master normal faults are high angle basement involved features that generated the main topographic contrast and exposing Lower Cretaceous units or older. In contrast, in the adjacent foot wall shortcuts only part of the syn-rift Lower Cretaceous sequence was deposited or more commonly was not deposited at all. Maximum paleo-temperatures reached by the basal Cretaceous units exposed in the hanging wall blocks of the foot wall shortcuts are always less than those of the Zircon FT partial annealing zone (250 Celsius degrade; 23,15 K). Finally we use AFT data to document that the foot wall shortcuts originated during the Late Miocene and later as shallowly dipping faults generating low elevation hanging wall areas. All the described features are present in the Ariari-Guatiquia region. However, northwards and along strike in the Eastern foothills there is a lot of partially analogue scenarios with respect to those described in the

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

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Gabriel E Ramos-Tafur

2006-09-01

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

Review Article: Lake and breach hazard assessment for moraine-dammed lakes: an example from the Cordillera Blanca (Peru

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A. Emmer

2013-06-01

Full Text Available Glacial lake outburst floods (GLOFs and related debris flows represent a significant threat in high mountainous areas across the globe. It is necessary to quantify this threat so as to mitigate their catastrophic effects. Complete GLOF hazard assessment incorporates two phases: the probability of water release from a given glacial lake is estimated through lake and breach hazard assessment while the endangered areas are identified during downstream hazard assessment. This paper outlines a number of methods of lake and breach hazard assessment, which can be grouped into three categories: qualitative, of which we outline eight; semi-quantitative, of which we outline two; and quantitative, of which we outline three. It is considered that five groups of critical parameters are essential for an accurate regionally focused hazard assessment method for moraine-dammed lakes in the Cordillera Blanca. These comprise the possibility of dynamic slope movements into the lake, the possibility of a flood wave from a lake situated upstream, the possibility of dam rupture following a large earthquake, the size of the dam freeboard (or ratio of dam freeboard, and a distinction between natural dams and those with remedial work. It is shown that none of the summarised methods uses all these criteria with, at most, three of the five considered by the outlined methods. A number of these methods were used on six selected moraine-dammed lakes in the Cordillera Blanca: lakes Quitacocha, Checquiacocha, Palcacocha, Llaca, Rajucolta, and Tararhua. The results have been compared and show that each method has certain advantages and disadvantages when used in this region. These methods demonstrate that the most hazardous lake is Lake Palcacocha.

X-ray color maps of the zoned garnets from Silgará Formation metamorphic rocks,SantanderMassif, Eastern Cordillera (Colombia

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Takasu Akira

2010-12-01

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The metamorphic rocks of the Lower Paleozoic Silgará Formation of the Santander Massif, Eastern Cordillera (Colombia, were affected by a Barrovian-type metamorphism under low to high temperature and medium pressure conditions. These rocks contain garnet porphyroblasts, which show several kinds of chemical zoning patterns. The garnet grains behave as closed systems with respect to the rock matrix. Most of the observed zoning patterns are due to gradual changes in physicochemical conditions during growth. However, some garnet grains show complex zoning patterns during multiple deformation and metamorphic events.

Estudio preliminar de la mineralización uranífera en la cordillera oriental, San Ramón, Oxapampa

OpenAIRE

Valencia, Jacinto

2014-01-01

Rocas intrusivas del magmatismo permo-triásico de la cordillera oriental, constituidas por granitos de San Ramón y Oxapampa, presentan buena favorabilidad como rocas fértiles en uranio, un granito de facie roja denominado monzo-granito; esta condición es el resultado de la ejecución del proyecto de cooperación del OIEA PER 2/16, a cargo de IPEN, “Mejora del conocimiento del potencial uranífero del Perú”. Los trabajos de campo han consistido en la revisión geológico-radiométrica y toma de mues...

Reassessment of the development and hazard of the Rampac Grande landslide, Cordillera Negra, Peru

Czech Academy of Sciences Publication Activity Database

Vilímek, V.; Klimeš, Jan; Torres, M.

2016-01-01

Roč. 3, 18 April (2016), č. článku 5. E-ISSN 2197-8670 Institutional support: RVO:67985891 Keywords : landslides * natural hazards * Cordillera Negra * Peru Subject RIV: DE - Earth Magnetism, Geodesy, Geography http://download.springer.com/static/pdf/602/art%253A10.1186%252Fs40677-016-0039-8.pdf?originUrl=http%3A%2F%2Fgeoenvironmental-disasters.springeropen.com%2Farticle%2F10.1186%2Fs40677-016-0039-8&token2=exp=1486369402~acl=%2Fstatic%2Fpdf%2F602%2Fart%25253A10.1186%25252Fs40677-016-0039-8.pdf*~hmac=2a499db60ac7d16e5bc5da6d0cb065804ae5a9b0c750bef6f8c6e5f93ae5a9db

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

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

2013-12-01

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

The reconstruction of a glacial lake outburst flood using HEC-RAS and its significance for future hazard assessments: an example from Lake 513 in the Cordillera Blanca, Peru

Czech Academy of Sciences Publication Activity Database

Klimeš, Jan; Benešová, M.; Vilímek, V.; Bouška, P.; Rapre, A.C.

2014-01-01

Roč. 71, č. 3 (2014), s. 1617-1638 ISSN 0921-030X R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : GLOFs * debris flow * natural hazard * HEC-RAS * Cordillera Blanca Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.719, year: 2014

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

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

2015-04-01

The regolith mantel is produced by weathering of bedrock through physical and biochemical processes. At the same time, the upper part of the regolith is eroded by gravity mass movements, water and wind erosion. Feedback's between production and erosion of soil material are important for soil development, and are essential to reach long-term steady-state in soil chemical and physical properties. Nowadays, long-term denudation rates of regolith can be quantified by using in-situ cosmogenic nuclides (CRN). If the soil thickness remains constant over sufficiently long time, soil production rates can be determined. However, the a priori assumption of long-term steady-state can be questionable in highly dynamic environments. In this study, we present analytical data from two independent isotopic techniques, in-situ cosmogenic nuclides and Uranium series disequilibrium. The disequilibrium of Uranium isotopes (238U, 234U, 230Th, 226Ra) is an alternative method that allows assessing soil formation rates through isotopic analysis of weathering products. Nine soil profiles were sampled in three different mountain ranges of the Betic Cordillera (SE Spain): Sierra Estancias, Filabres, Cabrera. All soils overly fractured mica schist and are very thin (< 60cm). In each soil profile, we sampled 4 to 6 depth slices in the soil profile, the soil-bedrock interface and (weathered) bedrock. Three of the nine soil profiles were sampled for U-series isotope measurements at EOST (University of Strasbourg). The surface denudation rates (CRN) are about the same in the Sierra Estancias and Filabres (26 ± 10 mm/ky) and increase up to 103 ± 47 mm/ky in the Sierra Cabrera. The spatial variation in soil denudation rates is in agreement with the variation in catchment-wide denudation rates presented by Bellin et al. (2014) which present the highest rates in the Sierra Cabrera (104-246mm/kyr). Moreover it roughly coincides with the pattern of long-term exhumation of the Betic Cordillera. Results

Intrusion of basaltic magma into a crystallizing granitic magma chamber: The Cordillera del Paine pluton in southern Chile

Science.gov (United States)

Michael, Peter J.

1991-10-01

The Cordillera del Paine pluton in the southernmost Andes of Chile represents a deeply dissected magma chamber where mafic magma intruded into crystallizing granitic magma. Throughout much of the 10x15 km pluton, there is a sharp and continuous boundary at a remarkably constant elevation of 1,100 m that separates granitic rocks (Cordillera del Paine or CP granite: 69 77% SiO2) which make up the upper levels of the pluton from mafic and comingled rocks (Paine Mafic Complex or PMC: 45 60% SiO2) which dominate the lower exposures of the pluton. Chilled, crenulate, disrupted contacts of mafic rock against granite demonstrate that partly crystallized granite was intruded by mafic magma which solidified prior to complete crystallization of the granitic magma. The boundary at 1,100 m was a large and stable density contrast between the denser, hotter mafic magma and cooler granitic magma. The granitic magma was more solidified near the margins of the chamber when mafic intrusion occurred, and the PMC is less disrupted by granites there. Near the pluton margins, the PMC grades upward irregularly from cumulate gabbros to monzodiorites. Mafic magma differentiated largely by fractional crystallization as indicated by the presence of cumulate rocks and by the low levels of compatible elements in most PMC rocks. The compositional gap between the PMC and CP granite indicates that mixing (blending) of granitic magma into the mafic magma was less important, although it is apparent from mineral assemblages in mafic rocks. Granitic magma may have incorporated small amounts of mafic liquid that had evolved to >60% SiO2 by crystallization. Mixing was inhibited by the extent of crystallization of the granite, and by the thermal contrast and the stable density contrast between the magmas. PMC gabbros display disequilibrium mineral assemblages including early formed zoned olivine (with orthopyroxene coronas), clinopyroxene, calcic plagioclase and paragasite and later-formed amphibole

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

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

2003-09-01

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

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

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Delgado Salazar, F.

2007-06-01

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

A new golden frog species of the genus Diasporus (Amphibia, Eleutherodactylidae from the Cordillera Central, western Panama

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Andreas Hertz

2012-05-01

Full Text Available We describe the frog species Diasporus citrinobapheus sp. n. from the Cordillera Central of western Panama. The new species differs from all other species in its genus in coloration, disk cover and disk pad shape, skin texture, advertisement call, and size. It is most similar to D. tigrillo, from which it differs in dorsal skin texture, relative tibia length, number of vomerine teeth, ventral coloration, dorsal markings, and relative tympanum size, and to D. gularis, from which it can be distinguished by the lack of membranes between the toes, adult size, posterior thigh coloration, and position of the choanae. We provide data on morphology, vocalization, and distribution of the new species, as well as brief information on its natural history.

A new golden frog species of the genus Diasporus (Amphibia, Eleutherodactylidae) from the Cordillera Central, western Panama.

Science.gov (United States)

Hertz, Andreas; Hauenschild, Frank; Lotzkat, Sebastian; Köhler, Gunther

2012-01-01

We describe the frog species Diasporus citrinobapheussp. n. from the Cordillera Central of western Panama. The new species differs from all other species in its genus in coloration, disk cover and disk pad shape, skin texture, advertisement call, and size. It is most similar to Diasporus tigrillo, from which it differs in dorsal skin texture, relative tibia length, number of vomerine teeth, ventral coloration, dorsal markings, and relative tympanum size, and to Diasporus gularis, from which it can be distinguished by the lack of membranes between the toes, adult size, posterior thigh coloration, and position of the choanae. We provide data on morpho- logy, vocalization, and distribution of the new species, as well as brief information on its natural history.

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

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Beatriz Cofré Espinoza

2014-09-01

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

Recalibration of the yellow Rhizocarpon growth curve in the Cordillera Blanca (Peru) and implications for LIA chronology

Science.gov (United States)

Jomelli, V.; Grancher, D.; Brunstein, D.; Solomina, O.

2008-01-01

A new lichen dating method and new moraine observations enabled us to improve the chronology of glacier advances in the Cordillera Blanca (Peru) during the Little Ice Age (LIA). Our results reveal that an early LIA glacial advance occurred around AD 1330 ± 29. However, a second major glacial advance at the beginning of the 17th century overlapped the earlier stage for most glaciers. Hence, this second glacial stage, dated from AD 1630 ± 27, is considered as the LIA maximum glacial advance in the Cordillera Blanca. During the 17th-18th centuries, at least three glacial advances were recorded synchronously for the different glaciers (AD 1670 ± 24, 1730 ± 21, and 1760 ± 19). The moraines corresponding to the two first stages are close to the one in 1630 suggesting a slow recession of about 18% in the total length of the glacier. From the LIA maximum extent to the beginning of the 20th century, the 24 glaciers have retreated a distance of about 1000 m, corresponding to a reduction of 30% in their length. This rate is comparable to that observed during the 20th century. Estimates of palaeo-Equilibrium Line Altitudes show an increase in altitude of about 100 m from the LIA maximum glacial extension at the beginning of the 17th century to the beginning of the 20th century. Because long time series are not available for precipitation and temperature, this glacial retreat is difficult to explain by past climate changes. However, there is a fair correspondence between changes in glacier length and the δ18O recorded in the Quelccaya ice core at a century timescale. Our current knowledge of tropical glaciers and isotope variations leads us to suggest that this common tropical signal reflects a change from a wet LIA to the drier conditions of today. Finally, a remarkable synchronicity is observed with glacial variations in Bolivia, suggesting a common regional climatic pattern during the LIA.

Cenozoic deformation from the Yakutat-North American collision to the eastern margin of the Northern Canadian Cordillera

Science.gov (United States)

Enkelmann, E.

2017-12-01

The western margin of the Northern Cordillera of North America is dominated by transform motion of the Yakutat microplate along the Fairweather fault system. In southeast Alaska the transform boundary changes to convergence and the oblique collision of the buoyant Yakutat microplate formed the St. Elias Mountains. One of the outstanding questions in understanding the St. Elias orogeny is how stress from the plate boundary has been transferred inboard and distributed strain in the North American plate. The timing, amount, and spatial pattern of deformation and rock exhumation have been studied using multiple thermochronology methods. Together the data reveal that Late Cenozoic deformation inboard of the Fairweather Fault and the colliding Yakutat plate corner at the St. Elias syntaxis was spatially very limited, resulting in rock exhumation within a cooling associated with Cordilleran deformation, and Paleocene-Eocene cooling due to spreading-ridge subduction. In contrast, the region west of the St. Elias syntaxis is dominated by convergence, which resulted in significant Cenozoic deformation in southeastern and southern Alaska. In the St. Elias orogen itself, most of the Late Cenozoic deformation and exhumation occurs within the Yakutat microplate and its Cenozoic sedimentary cover that composes the fold-thrust belt. The efficient interaction between tectonic uplift and glacial erosion resulted in rapid exhumation (>1 km/Myr) and extreme rates (4 km/Myr) that are localized at the syntaxis region and have shifted southward over the past 10 Myr. Far-field deformation reaches more than 500 km to the northwest of the convergent margin and caused mountain building in south-central Alaska. Deformation to the northeast is unclear. New thermochronology data from the eastern margin of the Northern Canadian Cordillera (Northwest Territory) reveal exhumation during the Oligocene to early Miocene. At this time, transform motion was already dominating the plate margin in the

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

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WILLIAM TRUJILLO-C.

2015-01-01

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

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

Science.gov (United States)

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

2017-08-01

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

Minimum 1D P wave velocity model for the Cordillera Volcanica de Guanacaste, Costa Rica

International Nuclear Information System (INIS)

Araya, Maria C.; Linkimer, Lepolt; Taylor, Waldo

2016-01-01

A minimum velocity model is derived from 475 local earthquakes registered by the Observatorio Vulcanologico y Sismologico Arenal Miravalles (OSIVAM) for the Cordillera Volcanica de Guanacaste, between January 2006 and July 2014. The model has consisted of six layers from the surface up to 80 km the depth. The model has presented speeds varying between 3,96 and 7,79 km/s. The corrections obtained from the seismic stations have varied between -0,28 to 0,45, and they have shown a trend of positive values on the volcanic arc and negative on the forearc, in concordance with the crustal thickness. The relocation of earthquakes have presented three main groups of epicenters that could be associated with activity in inferred failures. The minimum ID velocity model has provided a simplified idea of the crustal structure and aims to contribute with the improvement of the routine location of earthquakes performed by OSIVAM. (author) [es

La porosidad en las areniscas triásicas (Rama Aragonesa de la Cordillera Ibérica

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Arribas, J.

1984-12-01

Full Text Available Triassic sandstone's porosity (Buntsandstein and Muschelkalk facies from the Aragonesa Branch of the Iberian Range are studied, firstly at the sediment primary porosity calculation and secondly the porosity-reducing processes are analyzed. Processes creating secondary sandstone porosity can be established (dissolution and fracturing by the textural and genetic caracterization of the sandstone's voids. The dissolution of potassium feldspar, carbonate cement and barite cement, is related with meteoric pore-water flow alloys to intramesozoic unconformities, Fracturing porosity is related to Iberian Range tertiary structuration. Finally, we concluded that the amount of the sandstone's secondary porosity depends mainly on the original composition of the sediments and also on the geochemical sedimentary environments that control the first diagenetic stages (eodiagenesis, This fact manifests itself in the amount and types of variating porosities along the stratigraphic section.

Se estudia la porosidad en las areniscas triásicas (facies Buntsandstein y Muschelkalk de la Rama Aragonesa de la Cordillera Ibérica, partiendo del cálculo estimativo de la porosidad primaria del sedimento, para posteriormente analizar los distintos procesos diagenéticos que han intervenido en su destrucción (compactación mecánica, compactación química y cementación. La caracterización textural y genética de los poros en dichas areniscas permite establecer la existencia de procesos generadores de porosidad secundaria (disolución y fractura. La disolución del feldespato potásico, cemento carbonático y de baritina se relaciona con flujos de aguas meteóricas ligadas a discordancias intramesozoicas, mientras que la porosidad de fractura se asocia a la estructuración terciaria de la Cordillera Ibérica. Por ú1timo se concluye que la cantidad de porosidad secundaria en las areniscas estudiadas depende fundamentalmente de la composición original de los dep

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

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Andreo, B.

1995-04-01

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

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

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Gargiulo, María Florencia

2011-12-01

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

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

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Paola Katrina Ching

2016-07-01

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

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

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Miguel Avendaño

2008-03-01

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

Downscaling reanalysis data to high-resolution variables above a glacier surface (Cordillera Blanca, Peru)

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Hofer, Marlis; Mölg, Thomas; Marzeion, Ben; Kaser, Georg

2010-05-01

Recently initiated observation networks in the Cordillera Blanca provide temporally high-resolution, yet short-term atmospheric data. The aim of this study is to extend the existing time series into the past. We present an empirical-statistical downscaling (ESD) model that links 6-hourly NCEP/NCAR reanalysis data to the local target variables, measured at the tropical glacier Artesonraju (Northern Cordillera Blanca). The approach is particular in the context of ESD for two reasons. First, the observational time series for model calibration are short (only about two years). Second, unlike most ESD studies in climate research, we focus on variables at a high temporal resolution (i.e., six-hourly values). Our target variables are two important drivers in the surface energy balance of tropical glaciers; air temperature and specific humidity. The selection of predictor fields from the reanalysis data is based on regression analyses and climatologic considerations. The ESD modelling procedure includes combined empirical orthogonal function and multiple regression analyses. Principal component screening is based on cross-validation using the Akaike Information Criterion as model selection criterion. Double cross-validation is applied for model evaluation. Potential autocorrelation in the time series is considered by defining the block length in the resampling procedure. Apart from the selection of predictor fields, the modelling procedure is automated and does not include subjective choices. We assess the ESD model sensitivity to the predictor choice by using both single- and mixed-field predictors of the variables air temperature (1000 hPa), specific humidity (1000 hPa), and zonal wind speed (500 hPa). The chosen downscaling domain ranges from 80 to 50 degrees west and from 0 to 20 degrees south. Statistical transfer functions are derived individually for different months and times of day (month/hour-models). The forecast skill of the month/hour-models largely depends on

Late Pleistocene glacial fluctuations in Cordillera Oriental, subtropical Andes

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

2017-09-01

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

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

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EUGENIO GARCES FELIÚ

2010-04-01

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

La intrusión de Cerro Redondo (Pérmico Inferior, Cordillera Ibérica, Zaragoza): reconstrucción 3D y modelo de emplazamiento

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Majarena Serrano, Urbez; Gil Imaz, Andrés; Lago San José, Marceliano; Galé, Carlos

2017-01-01

La intrusión subvolcánica de Cerro Redondo (Cordillera Ibérica, Zaragoza), de edad Pérmico Inferior, muestra una composición dactíca, una naturaleza calcoalcalina y se caracteriza por presentar una marcada estructuración interna determinada por un bandeado subvertical y d e espaciado variable (1-25 cm), que se encuentra afectado por numerosos pliegues d e flujo magmático de distinta escala (desde centimétrica hasta hectométrica). El estudio cartográfico y de la anisotropia de la susceptib...

Molecular characterization and genetic diversity of ESBL-producing Escherichia coli colonizing the migratory Franklin's gulls (Leucophaeus pipixcan) in Antofagasta, North of Chile.

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Báez, John; Hernández-García, Marta; Guamparito, Constanza; Díaz, Sofía; Olave, Abdon; Guerrero, Katherine; Cantón, Rafael; Baquero, Fernando; Gahona, Joselyne; Valenzuela, Nicomedes; Del Campo, Rosa; Silva, Juan

2015-02-01

The role of wild animals, particularly migratory birds, in the dissemination of antibiotic-resistant bacteria between geographically distant ecosystems is usually underestimated. The aim of this work was to characterize the Escherichia coli population from Franklin's gull feces, focusing on the extended-spectrum β-lactamase (ESBL)-producing strains. In the summer of 2011, 124 fecal swabs from seagulls (1 of each) migrating from the United States and Canada to the coast of Antofagasta, north of Chile, were collected. Samples were seeded on MacConkey agar supplemented with 2 μg/ml of cefotaxime and a single colony from each plate was tested for ESBL production by the double-disk ESBL synergy test. Antibiotic susceptibility was determined by the disk diffusion method and blaESBL genes were amplified and sequenced. The genetic diversity of isolates was explored by pulsed-field gel electrophoresis (PFGE)-XbaI and multilocus sequence typing. A total of 91 E. coli isolates with high rates of antibiotic resistance were identified. Carbapenemase production was not detected, whereas 67 of the 91 (54%) isolates exhibited an ESBL phenotype due to the presence of CTX-M-15 (61.3%), CTX-M-2 (19.3%), CTX-M-22 (16.1%), and CTX-M-3 (1.6%) coding genes. High genetic diversity was observed, with 30 PFGE patterns and 23 sequence types (STs), including ST131 (18%), ST44 (15%), ST617 (9%), and ST10 (9%). Results presented here are complementary to those previously reported by Hernández et al. in the same gull species, but located in the Central Region of Chile. Differences observed between gulls from both areas lead us to hypothesize that gulls from the northern location retain, as gut carriers, those resistant bacteria acquired in the United States and/or Canada.

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

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Quentin Struelens

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

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

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

2017-01-01

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

Geomorphological evidence of warm-humid and cold-dry glaciations in the dry western Cordillera of the tropical Peruvian Andes

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Mächtle, B.; Hein, A. S.; Dunai, T.; Eitel, B.

2012-04-01

The western Cordillera of the Andes (14°30'S, 74°W) is characterized by high altitudes, strong radiation and semi-arid conditions. Therefore, glacial processes and resulting landforms differ markedly from these of the outer-tropics. However, under sub-arctic conditions similar glacial landforms occur. This congruence can be explained by comparable environmental conditions, which determine the dynamics of ice flow, glacial erosion, debris production as well as moraine deposition. Outside the higher latitudes, typical sub-arctic glacial landforms as controlled moraines and trimline moraines (Evans 2009, Ó Cofaigh et al. 2005) remained undescribed until now. These landforms result from polythermal or cold-basal ice flow, respectively, which is typical for polar conditions. Beside this, we also found steep lateral moraines, which give evidence of increased ice thickness, debris production and deposition and warm-basal ice flow, which is conceivable only for alpine-type valley glaciers. Striations of the bedrock give evidence of accompanied basal erosion. Coexisting trimline moraines and steep lateral moraines rule out the influence of topography on ice thickness and the resulting thermal regime. Therefore, we match the different moraine types to changes in ice thickness, which was controlled by considerable precipitation changes during the last glaciation. An erroneous classification of the observed boulder associations as trimline moraine due to selective erosion after deposition can be excluded due to general arid conditions, slow weathering and the chronological proximity of only a few millennia between both landforms, determined from cosmogenic nuclides. Therefore, the occurrence of different thermal regimes gives evidence of considerable changes in precipitation during the last glaciation - but furthermore requires an associated change in the thermal conditions to explain the very close spatial position of both ice margins. Changes in ice volume must have

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

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Jorge Brito M.

2013-01-01

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

'El león de la cordillera'. Primo Capraro y el desempeño empresario en la región del nahuel Huapi, 1902-1932

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Méndez Laura

2009-01-01

Full Text Available La historia económica de la Patagonia Norte vivió cambios radicales en el período 1902-1932. Bariloche, un pequeño pueblo de frontera sobre la cordillera de los Andes, se convirtió en un centro turístico internacional. Este artículo pretende explicar el proceso de transformación económica de este espacio social, a través del comportamiento empresario de Primo Capraro, un inmigrante italiano que se convirtió en el empresario más importante de la región.

Proglacial hydrology in the tropical Andes: lessons from the Cordillera Blanca, Peru (Invited)

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McKenzie, J. M.; Mark, B. G.; Baraer, M.

2009-12-01

Understanding the complexities of tropical Andean hydrology is critical for managing modern water resources and interpreting paleohydrologic records. Glaciers are the most visible component of these systems, responding to global climate change and acting as critical hydrologic reservoirs. Tropical Andean glaciers are undergoing rapid retreat with complex impacts on the downstream hydrology. Groundwater is also an important component of the Andean regional hydrologic system, but its contribution is difficult to assess due to remote site access, minimal baseline data, and lack of continuous historical discharge and precipitation measurements. We have synthesized hydrochemical data from synoptically sampled glacial melt water, groundwater, precipitation, and stream discharge collected intermittently between 1998 and July 2008 throughout the Callejon de Huaylas, a 5000 km2 watershed that drains the western side of the Cordillera Blanca in northern Perú. Our data from 2004 to 2006 show systematic annual shifts in the isotopic ratios (δ18O and δ2H) of river water, indicating an increase in glacial melt water input, and we are able to use these changes across the Cordillera Blanca to estimate an average increase of 1.6 (± 1.1) % in the specific discharge of the glacierized basins. Enhanced total stream discharge in more glacierized catchments (>20% glacier area) is demonstrated by a significant positive trend in a 43-year discharge anomaly record. Our hydrochemical basin characterization method (HBCM) uses chemical mass balance mixing to quantify the contribution of glacial melt water, groundwater, and surface runoff to streams for different valleys and nested watersheds in the Callejon de Huaylas. The Yanamarey basin (7% glaciated) has been observed since 1998 and the HBCM results show good agreement with measured stream discharge (maximum R2 of 0.99) for monthly cumulative values. These results suggest that for most of the studied years groundwater is the main

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

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KEVIN N. PAGE

2004-03-01

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

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

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

2017-11-01

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

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

International Nuclear Information System (INIS)

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

2017-01-01

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

A NEW ARBORESCENT SPECIES OF ZAMIA (CYCADALES, ZAMIACEAE FROM THE DEPARTMENT OF HUILA, EASTERN CORDILLERA OF COLOMBIA

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Calonje Michael

2012-12-01

Full Text Available Zamia huilensis Calonje, Esquivel, & D.W. Stev., a new arborescent species from theEastern Cordillera of Colombia (Department of Huila, is described and illustrated. Itis compared to Z. muricata Willd., which has similar leaflet shape, and to Z. tolimensisCalonje, Esquivel & D.W. Stev., with which it shares some reproductive characters.It differs from Z. muricata in having an arborescent trunk, beige-yellow to beigeovulate strobili supported by short peduncles, and microsporangia aggregated intoa single group on abaxial side of microsporophyll; it differs from Z. muricata in thesubterranean trunk, dark brown to black ovulate strobili supported by long peduncles,and microsporangia separated into two groups on abaxial side of microsporophylls.It differs from Z. tolimensis in having an overall smaller size, leaflets that are notstrongly falcate and with margins toothed below the distal half, compared to Z. tolimensiswhich is a much larger plant, and has strongly falcate leaflets that are nottoothed below the distal half.

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

OpenAIRE

Struelens, Quentin; Pomar, K. G.; Herrera, S. L.; Huanca, G. N.; Dangles, Olivier; Rebaudo, François

2017-01-01

Grazing areas management is of utmost importance in the Andean region. In the valleys of the Bolivian Cordillera Real near La Paz, pastoralism constitutes the traditional way for people to insure food security and economical sustainability. In these harsh mountains, unique and productive wetlands sustained by glacial water streams are of utmost importance for feeding cattle herds during the dry season. After the colonization by the Spanish, a shift in livestock species has been observed, with...

Urinary excretion of platinum, arsenic and selenium of cancer patients from the Antofagasta region in Chile treated with platinum-based drugs

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Román Domingo A

2012-04-01

Full Text Available Abstract Background Arsenic exposure increases the risk of non-cancerous and cancerous diseases. In the Antofagasta region in Chile, an established relationship exists between arsenic exposure and the risk of cancer of the bladder, lung and skin. Platinum-based drugs are first-line treatments, and many works recognise selenium as a cancer-fighting nutrient. We characterised the short-term urinary excretion amounts of arsenic, selenium and platinum in 24-h urine samples from patients with lung cancer and those with cancer other than lung treated with cisplatin or/and carboplatin. As - Se - Pt inter-element relationships were also investigated. Results The amounts of platinum excreted in urine were not significantly different between patients with lung cancer and those with other cancers treated with cisplatin, despite the significant variation in platinum amounts supplied from platinum-based drugs. In general, the analytical amounts of excreted selenium were greater than those for arsenic, which could imply that platinum favours the excretion of selenium. For other types of cancers treated with drugs without platinum, excretion of selenium was also greater than that of arsenic, suggesting an antagonist selenium-anti-cancer drug relationship. Conclusions Regards the baseline status of patients, the analytical amounts of excreted Se is greater than those for As, particularly, for cisplatin chemotherapy. This finding could imply that for over the As displacement Pt favours the excretion of Se. The analytical amounts of excreted Se were greater than those for As, either with and without Pt-containing drugs, suggesting an antagonist Se-anti-cancer drug relationship. However, it seemed that differences existed between As - Se - Pt inter-element associations in patients treated for lung cancer in comparison with those treated for cancer other than lung. Therefore, knowledge obtained in this work, can contribute to understanding the arsenic cancer

Precipitation history of the central Atacama Desert since the Miocene as reconstructed from clay pan records of the Costal Cordillera/ N Chile

Science.gov (United States)

Wennrich, V.; Melles, M.; Diederich, J. L.; Fernández Galego, E.; Ritter, B.; Brill, D.; Niemann, K.; Rolf, C.; Dunai, T. J.

2017-12-01

Hyperaridity is a major limitation of Earth-surface processes and biological activity in the Atacama Desert of N Chile, one of the oldest and the driest deserts on Earth. But even the hyperarid core of the Atacama Desert of N Chile has experienced sever precipitation events, e.g., during the flash floods in 2015. On geological timescales, the overall aridity that is postulated to have lasted at least since the early Miocene was punctuated by distinct pluvial events. Such wetter conditions, e.g. during the Miocene, caused widespread lake-formation in the Central Depression and Coastal Cordillera, but also caused amplified surface processes, changes in vegetation dynamics, and enabled the dispersal of species. Unfortunately, due to the limited number and heterogeneous appearance of climate archives from the central Atacama, it's longer-scale precipitation history is still a matter of controversy. This study aims to study continuous longterm (Pleistocene-Miocene) paleoclimatic and environmental records from the hyperarid core of the Atacama Desert covering the last >10 Ma. Therefor we investigate clay pans records from endorheic basins in the Coastal Cordillera mostly formed by blocking of drainage by tectonic movement. The clay pans under study are located along a latitudinal transect across the hyperarid core of the Atacama, and thus, are assumed to have recorded local and regional precipitation variations on different timescales. The investigated sequences exhibit significant changes in the sedimentological, geochemical, and mineralogical properties due to changes in precipitation, but also in the weathering and erosion in the catchments. Diatom and phytolith remains preserved in these records clearly point to significant water bodies during the wettest periods and a significant vegetation cover. The results shed a new light on the timing, frequency, and the driving mechanisms of the intervening pluvial phases.

Fission track thermochronology of Neogene plutons in the Principal Andean Cordillera of central Chile (33-35°S: Implications for tectonic evolution and porphyry Cu-Mo mineralization Termocronología mediante trazas de fision de plutones neógenos en la Cordillera Principal Andina de Chile central (33-35°S: Implicancias para la evolución tectónica y mineralización de pórfidos de Cu-Mo

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Víctor Maksaev

2009-07-01

Full Text Available Apatite fission track data for Miocene plutons of the western slope of the Principal Andean Cordillera in central Chile (33-35°S define a distinct episode of enhanced crustal cooling through the temperature range of the apatite partial annealing zone (~125-60°C from about 6 to 3 Ma. This cooling episode is compatible with accelerated exhumation of the plutons at the time of Pliocene compressive tectonism, and mass wasting on the western slope of the Principal Andean Cordillera in central Chile. The timing coincides with the southward migration of the subducting Juan Fernández Ridge and the development of progressive subduction flattening northward of 33°S. It also corresponds to the time of active magmatic-hydrothermal processes and rapid unroofing of the world class Río Blanco-Los Bronces and El Teniente porphyry Cu-Mo deposits. Zircon fission track ages coincide with previous 40Ar/39Ar dates of the intrusions, and with some of the apatite fission track ages, being coherent with igneous-linked, rapid cooling following magmatic intrusion. The thermochronologic data are consistent with a maximum of about 8 km for Neogene exhumation of the plutons.Los datos de trazas de fision en apatita de plutones miocenos del flanco oeste de la Cordillera Principal de Chile central (33-35°S definen un episodio distintivo de enfriamiento acelerado a través del rango de temperatura de la zona de acortamiento parcial de trazas en apatita (~125-60°C entre los 6 a 3 Ma. Este episodio de enfriamiento es compatible con exhumación rápida de los plutones al tiempo del tectonismo compresivo plioceno y remociones en masa en el flanco oeste de la Cordillera Principal en Chile central. El período de tiempo coincide con la migración hacia el sur de la subducción de la Dorsal de Juan Fernández y con el desarrollo de un aplanamiento progresivo de la subducción hacia el norte de los 33°S. También corresponde al tiempo de actividad magmático-hidrotermal y r

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

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Federico Miguel Bobillo

2015-06-01

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

A study of tectonic activity in the Basin-Range Province and on the San Andreas Fault. No. 2: Lithospheric structure, seismicity, and contemporary deformation of the United States Cordillera

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Smith, R. B.

1986-01-01

The structural evolution of the U.S. Cordillera has been influenced by a variety of tectonic mechanisms including passive margin rifting and sedimentation; arc volcanism; accretion of exotic terranes; intraplate magmatism; and folding and faulting associated with compression and extension processes that have profoundly influenced the lithospheric structure. As a result the Cordilleran crust is laterally inhomogeneous across its 2000 km east-west breadth. It is thin along the West Coast where it has close oceanic affinities. The crust thickens eastward beneath the Sierra Nevada, then thins beneath the Basin-Range. Crustal thickening continues eastward beneath the Colorado Plateau, the Rocky Mountains, and the Great Plains. The total lithospheric thickness attains 65 km in the Basin-Range and increases eastward beneath the Colorado Plateau. The upper-crust, including the crystalline basement of the Cordillera, has P sub G velocities of 6 km/s in the Basin-Range and Rio Grande Rift. Lower P sub G velocities of 5.4 to 5.7 km/s are associated with the youthful Yellowstone, Valles and Long Valley calderas and the Franciscan assemblage of the western coastal margin. Averaged crustal velocity reflects integrated tectonic evolution of the crust-thick silicic bodies, velocity reversals, and a thin crust produce low averaged velocities that are characteristic of a highly attenuated and thermally deformed crust.

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

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Hermes, Jacobus J.

1985-08-01

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

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

Precise chronologies of Holocene glacial culminations in the Cordillera Vilcabamba of southern Peru

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Licciardi, J. M.; Schaefer, J. M.; Schweinsberg, A. D.

2012-12-01

Records of past fluctuations in climatically sensitive tropical mountain glaciers are among the best indicators of regional paleoclimatic trends and controls. The majority of the world's present-day tropical glaciers are found in the Peruvian Andes, but accurate and precise chronologies of past glacial activity in this region remain relatively scarce, particularly during the Holocene. Here we present ~50 new 10Be exposure ages derived from boulders on well-preserved moraine successions in several glaciated drainages in the Cordillera Vilcabamba of southern Peru (13°20'S latitude). The new results suggest that prominent moraines in these valleys are correlative with previously published moraine ages near Nevado Salcantay in this range (Licciardi et al., 2009), but also expand on the initial surface exposure chronologies to reveal additional periods of glacier stabilization not found in previous work. A provisional composite chronology that merges the new and previously obtained moraine ages indicates at least five discrete glacial culminations from the Lateglacial to the late Holocene. Forthcoming 10Be ages from an additional ~50 samples collected from moraine boulders will increase the precision and completeness of the Vilcabamba moraine chronologies. Basal radiocarbon ages are being developed from bog and lake sediments in stratigraphic contact with the 10Be-dated moraines. These new 14C age data will help constrain the local cosmogenic 10Be production rate, thereby increasing the accuracy of the 10Be chronologies.

Identificación, caracterización y dinámica de las geoformas glaciales y periglaciales en la Cordillera de los Andes a través de sensores remotos

OpenAIRE

Falaschi, Daniel

2015-01-01

El presente trabajo de Tesis Doctoral tuvo el objetivo de estudiar los glaciares y glaciares de escombros en tres regiones montañosas a lo largo de la Cordillera de los Andes Argentina: Monte San Lorenzo (Provincia de Santa Cruz), Volcán Domuyo (Provincia de Neuquén), y Nevados de Cachi (Provincia de Salta). Cada uno de estos sitios presenta características climáticas propias, representativas de tres porciones particulares de los Andes: Andes Patagónicos Meridionales, Andes Centrales Meridion...

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

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

2017-03-01

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

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

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

2015-01-01

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

FORMACIÓN BARROSO: ARCO VOLCÁNICO TOLEITICO Y DIABASAS DE SAN JOSÉ DE URAMA: UN PRISMA ACRECIONARIO T-MORB EN EL SEGMENTO NORTE DE LA CORDILLERA OCCIDENTAL DE COLOMBIA

OpenAIRE

RODRÍGUEZ G., GABRIEL; ARANGO, MARÍA ISABEL

2013-01-01

En el Segmento Norte de la Cordillera Occidental, entre las fallas Cauca-Almaguer y Dabeiba-Pueblo Rico afloran dos unidades volcánicas, que fueron agrupadas en trabajos anteriores con el nombre de Formación Barroso y que en realidad corresponden a unidades de diferente edad y ambiente geotectónico, que se denominan Diabasas de San José de Urama y Formación Barroso. Las Diabasas de San José de Urama corresponden a bloques tectónicos y cuerpos de diabasas y basaltos almohadillados con texturas...

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

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

2015-12-01

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

10Be dating of late-glacial moraines near the Cordillera Vilcanota and the Quelccaya Ice Cap, Peru

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Kelly, M. A.; Thompson, L. G.

2004-12-01

The surface exposure method, based on the measurement of cosmogenic 10Be produced in quartz, is applied to determine the age of deposition of glacial moraines near the Cordillera Vilcanota and the Quelccaya Ice Cap (about 13° S, 70° W) in southeastern Peru. These data are useful for examining the timing of past glaciation in the tropical Andes and for comparison with chronologies of glaciation at higher latitudes. The preliminary data set consists of more than ten surface exposure ages. Samples used for dating are from the surfaces of boulders on a set of prominent moraines about four kilometers away from the present ice margins. The age of the moraine set was previously bracketed by radiocarbon dating of peat associated with the glacial deposits. Based on radiocarbon ages, these moraines were formed during the late-glacial period, just prior to the last glacial-interglacial transition. The surface exposure dating method enables the direct dating of the moraines. Surface exposure dates are cross-checked with the previously existing radiocarbon dates and provide a means to improve the chronology of past glaciation in the tropical Andes.

Proglacial Hydrogeology of the Cordillera Blanca (Peru): Integrating Field Observations with Hydrogeophysical Inversions to Inform Groundwater Flow Simulations and Conceptual Models

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Glas, R. L.; Lautz, L.; McKenzie, J. M.; Moucha, R.; Mark, B. G.

2017-12-01

Geological and depositional conditions of the glaciated Cordillera Blanca in Peru have given way to proglacial aquifer systems that contribute substantially to regional streams and rivers, particularly during the dry season. As glacial retreat accelerates, the dry season water budget will be increasingly dominated by groundwater inputs, although predictions of future groundwater quantities require estimations of groundwater storage capacity, aquifer extents, and groundwater residence time. We present a characterization of the sediment structure in a prototypical proglacial valley in the central portion of the range, the Quilcayhuanca Valley. Northern and Central valleys of the Cordillera Blanca feature ubiquitous talus deposits that line the steep granite walls, and have become partially buried beneath lacustrine sediments deposited in proglacial lake beds. The portion of the talus still exposed near the valley walls provides recharge to deeper portions of the valley aquifers that underlie lacustrine clay, resulting in a confined aquifer system that is connected to the surface via perennial springs. Seismic refraction surveys reveal an interface separating relatively slow ( 400-800 m/s) and fast ( 2500 m/s) p-wave velocities. The depth of this refractor coincides with the depth to buried talus observed in drilling records. Electrical resistivity tomography profiles of the same transect show depths near the buried talus to be relatively conductive (10-100 Ωm). At these depths, we hypothesize that electrical conductance is elevated by saturated clay particles in the sediment matrix of the talus deposit. The resistivity models all show a more resistive ( 700 Ω m) region at depth, likely corresponding to a more hydraulically conductive material. The resistive zone is interpreted to be a deeper portion of a buried talus deposit that did not accumulate clay in the matrix. Other possibilities include a thick deposit of gravelly glacial outwash, or a relatively clay

Space-time evolution of a growth fold (Betic Cordillera, Spain). Evidences from 3D geometrical modelling

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Martin-Rojas, Ivan; Alfaro, Pedro; Estévez, Antonio

2014-05-01

We present a study that encompasses several software tools (iGIS©, ArcGIS©, Autocad©, etc.) and data (geological mapping, high resolution digital topographic data, high resolution aerial photographs, etc.) to create a detailed 3D geometric model of an active fault propagation growth fold. This 3D model clearly shows structural features of the analysed fold, as well as growth relationships and sedimentary patterns. The results obtained permit us to discuss the kinematics and structural evolution of the fold and the fault in time and space. The study fault propagation fold is the Crevillente syncline. This fold represents the northern limit of the Bajo Segura Basin, an intermontane basin in the Eastern Betic Cordillera (SE Spain) developed from upper Miocene on. 3D features of the Crevillente syncline, including growth pattern, indicate that limb rotation and, consequently, fault activity was higher during Messinian than during Tortonian; consequently, fault activity was also higher. From Pliocene on our data point that limb rotation and fault activity steadies or probably decreases. This in time evolution of the Crevillente syncline is not the same all along the structure; actually the 3D geometric model indicates that observed lateral heterogeneity is related to along strike variation of fault displacement.

The energy balance of tropical Glaciar Artesonraju, Cordillera Blanca, Perú - AWS-measurements and numerical modeling

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Galos, S.; Mölg, T.; MacDonell, S.; Großhauser, M.; Marzeion, B.

2012-04-01

Like in most regions of the world, tropical glaciers in the Peruvian Andes have experienced considerable mass loss during the last decades. In order to better understand and correctly interpret the ongoing glacier changes in this region, we need to examine the driving processes behind these changes. Therefore we installed several automatic weather stations (AWS) in the Cordillera Blanca mountain range. Two of these stations are situated in the ablation area of Glaciar Shallap and Glaciar Artesonraju, while four other stations were established in the vicinity of the two glaciers. The resulting eight year record of meteorological data is analyzed and finally used as input for a physically based numerical energy and mass balance model, which in a first step was applied to the ablation zone of Glaciar Artesonraju (8.96° S / 77.63° W). In July 2010, eddy covariance measurements were carried out on the glacier surface. The resulting data was used to calibrate the parametrization scheme for the turbulent fluxes of sensible and latent heat. Finally the model output was validated against ablation data from a sonic ranger and from single stake ablation measurements. The model results were interpreted with special respect to the seasonal fluctuation in atmospheric moisture (tropical wet / dry season).

Chemical classification and geotermometry of chlorites from the cretaceous Santa Rosa and Lutitas de Macanal formations, eastern emerald belt, eastern cordillera, Colombia

International Nuclear Information System (INIS)

Silva Arias, Alejandro; Mantilla Figueroa, Luis Carlos; Terraza Melo, Roberto

2010-01-01

The study of the chemical composition of chlorites from the Santa Rosa and Lutitas de Macanal formations in the eastern emerald belt (eastern cordillera), are used to estimate the formation temperature of these minerals and the associated hydrothermal fluids. The chlorites were analyzed using the classification proposed by hey (1954), foster (1962), and Bailey (1980); and the formation temperature is calculated from empirical geothermometers from kranidiotis and Maclean (1987), Cathelineau (1988), Jowett (1991) and Xie et al. (1997). Chlorites in hydrothermally altered rocks associated with emerald mineralization of the Santa Rosa formation is classified as clinochlore and formed at temperatures of 354 Celsius degrade; this temperature is consistent with the fluid inclusions in emeralds of the same formation. Chlorites in veins from Lutitas de Macanal Formation are classified as chamosites and formed at lower temperatures between 210 to 225 Celsius degrade

Efecto del secado de las muestras sobre la extracción selectiva de Fe y A1 activos en Andisoles del norte de la cordillera central Colombiana.

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Jaramillo J. Daniel F.

2000-12-01

Full Text Available Muestras secadas al aire y sin secar de cinco perfiles de Andisoles del norte de la cordillera central colombiana fueron sometidas a extracción con oxalato ácido de amonio y con pirofosfato de sodio. En los extractos de oxalato se determinaron A1, Fe y Si y en los de pirofosfato A1 y Fe. El secado de las muestras redujo significativamente al 95% la cantidad de A1 y de Fe extraída con oxalato ácido, dificultando la clasificación de los suelos en el orden Andisol utilizando los parámetros de la taxonomía del USDA.

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

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

2014-12-01

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

Spatial gradient of chemical weathering and its coupling with physical erosion in the soils of the Betic Cordillera (SE Spain)

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Schoonejans, Jerome; Vanacker, Veerle; Opfergelt, Sophie; Ameijeiras-Mariño, Yolanda; Kubik, Peter

2015-04-01

The production and denudation of soil material are controlled by chemical weathering and physical erosion which influence one another. Better understanding and quantification of this relationship is critical to understand biogeochemical cycles in the critical zone. The intense silicate weathering that is taking place in young mountain ranges is often cited to be a negative feedback that involves a long-term reduction of the atmospheric CO2 and the temperature cooling. However the possible (de)coupling between weathering and erosion is not fully understood for the moment and could reduce the effect of the feedback. This study is conducted in the eastern Betic Cordillera located in southeast Spain. The Betic Cordillera is composed by several mountains ranges or so-called Sierras that are oriented E-W to SE-NW and rise to 2000m.a.s.l. The Sierras differ in topographic setting, tectonic activity, and slightly in climate and vegetation. The mountain ranges located in the northwest, such as the Sierra Estancias, have the lowest uplift rates ( ~20-30 mm/kyr); while those in the southeast, such as the Sierra Cabrera, have the highest uplift rates ( >150mm/kyr). The sampling was realised into four small catchments located in three different Sierras. In each of them, two to three soil profiles were excavated on exposed ridgetops, and samples were taken by depth slices. The long-term denudation rate at the sites is inferred from in-situ 10Be CRN measurements. The chemical weathering intensity is constrained using a mass balance approach that is based on the concentration of immobile elements throughout the soil profile (CDF). Our results show that the soil depth decreases with an increase of the denudation rates. Chemical weathering accounts for 5 to 35% of the total mass lost due to denudation. Higher chemical weathering intensities (CDFs) are observed in sites with lower denudation rates (and vice versa). The data suggest that chemical weathering intensities are strongly

The contribution of the young Cretaceous Caribbean Oceanic Plateau to the genesis of late Cretaceous arc magmatism in the Cordillera Occidental of Ecuador

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Allibon, J.; Monjoie, P.; Lapierre, H.; Jaillard, E.; Bussy, F.; Bosch, D.; Senebier, F.

2008-12-01

The eastern part of the Cordillera Occidental of Ecuador comprises thick buoyant oceanic plateaus associated with island-arc tholeiites and subduction-related calc-alkaline series, accreted to the Ecuadorian Continental Margin from Late Cretaceous to Eocene times. One of these plateau sequences, the Guaranda Oceanic Plateau is considered as remnant of the Caribbean-Colombian Oceanic Province (CCOP) accreted to the Ecuadorian Margin in the Maastrichtien. Samples studied in this paper were taken from four cross-sections through two arc-sequences in the northern part of the Cordillera Occidental of Ecuador, dated as (Río Cala) or ascribed to (Macuchi) the Late Cretaceous and one arc-like sequence in the Chogòn-Colonche Cordillera (Las Orquídeas). These three island-arcs can clearly be identified and rest conformably on the CCOP. In all four localities, basalts with abundant large clinopyroxene phenocrysts can be found, mimicking a picritic or ankaramitic facies. This mineralogical particularity, although not uncommon in island arc lavas, hints at a contribution of the CCOP in the genesis of these island arc rocks. The complete petrological and geochemical study of these rocks reveals that some have a primitive island-arc nature (MgO values range from 6 to 11 wt.%). Studied samples display marked Nb, Ta and Ti negative anomalies relative to the adjacent elements in the spidergrams characteristic of subduction-related magmatism. These rocks are LREE-enriched and their clinopyroxenes show a tholeiitic affinity (FeO T-TiO 2 enrichment and CaO depletion from core to rim within a single crystal). The four sampled cross-sections through the island-arc sequences display homogeneous initial Nd, and Pb isotope ratios that suggest a unique mantellic source for these rocks resulting from the mixing of three components: an East-Pacific MORB end-member, an enriched pelagic sediment component, and a HIMU component carried by the CCOP. Indeed, the ankaramite and Mg

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

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

2010-12-01

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

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

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

2014-05-01

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

Levelling Profiles and a GPS Network to Monitor the Active Folding and Faulting Deformation in the Campo de Dalias (Betic Cordillera, Southeastern Spain)

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Marín-Lechado, Carlos; Galindo-Zaldívar, Jesús; Gil, Antonio José; Borque, María Jesús; de Lacy, María Clara; Pedrera, Antonio; López-Garrido, Angel Carlos; Alfaro, Pedro; García-Tortosa, Francisco; Ramos, Maria Isabel; Rodríguez-Caderot, Gracia; Rodríguez-Fernández, José; Ruiz-Constán, Ana; de Galdeano-Equiza, Carlos Sanz

2010-01-01

The Campo de Dalias is an area with relevant seismicity associated to the active tectonic deformations of the southern boundary of the Betic Cordillera. A non-permanent GPS network was installed to monitor, for the first time, the fault- and fold-related activity. In addition, two high precision levelling profiles were measured twice over a one-year period across the Balanegra Fault, one of the most active faults recognized in the area. The absence of significant movement of the main fault surface suggests seismogenic behaviour. The possible recurrence interval may be between 100 and 300 y. The repetitive GPS and high precision levelling monitoring of the fault surface during a long time period may help us to determine future fault behaviour with regard to the existence (or not) of a creep component, the accumulation of elastic deformation before faulting, and implications of the fold-fault relationship. PMID:22319309

Geophysical constraints on the mantle structure of the Canadian Cordillera and North America Craton

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Yu, T. C.; Currie, C. A.; Unsworth, M. J.

2017-12-01

In western Canada, geophysical data indicate that there is a pronounced contrast in mantle structure between the Canadian Cordillera (CC) and North America craton (NAC). The CC is characterized by lower mantle seismic velocity, higher surface heat flow, lower mantle electrical resistivity and lower effective elastic thickness. These observations are consistent with two distinct thermal regimes: the CC has hot and thin lithosphere, while the NAC lithosphere is cool and thick. The boundary between the CC and NAC coincides with the south-north trending Rocky Mountain Trench - Tintina Fault system. Earlier studies have hypothesized that the thin CC lithosphere is maintained by small-scale convection of hydrated mantle, whereas the NAC lithosphere is dry and resistant to thinning. Here, we test this hypothesis through a detailed examination of two independent data sets: (1) seismic shear-wave (Vs) tomography models and (2) magnetotelluric (MT) measurements of mantle electrical resistivity. We analyze tomography model NA07 at 50-250 km depth and create a mapping of Vs to temperature based on mantle composition (via Perple_X) and a correction for anelasticity. For the CC, the calculated temperature is relatively insensitive to mantle composition but strongly depends on the water content and anelastic correction. With a laboratory-based correction, the estimated temperature is 1150 °C at 100 km depth for wet mantle, compared to 1310 °C for dry mantle; no melt is predicted in either case. An empirical anelastic correction predicts a 115 °C hotter mantle and likely some melt. In contrast, composition is the main control on the calculated temperature for the NAC, especially at depths electrical resistivity is sensitive to mantle temperature and hydration.

Delta progradation and Neoglaciation, Laguna Parón, Cordillera Blanca, Peru

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Seltzer, Geoffrey O.; Rodbell, Donald T.

2005-10-01

The history of Holocene glaciation serves as an important record of glacier mass balance and, therefore, of climatic change. The moraine record of Holocene glaciation in the tropical Andes, however, is fragmentary and poorly dated. In contrast, increases in the rate of accumulation of inorganic sediment in glacier-fed lakes have been linked to periods of Neoglaciation in many mountain regions. The interpretation of such a record of Neoglaciation from sediment cores in glacier-fed lakes in the tropical Andes can provide the continuity and chronologic control that is lacking in the existing moraine record. Unusual exposures of glacial lacustrine sediment in the Cordillera Blanca, Peru, provide a rare opportunity to assess the link between climatic change, glaciation, and lacustrine sedimentation.Intentional lowering of water levels in Laguna Parón (9°S, 77°44 W, 4200 m a.s.l.) in 1985 resulted in the incision and exposure of at least 20 m of deltaic deposits at the eastern end of the lake. Three deltaic units can be identified: horizontal topset beds, steeply dipping and deformed foreset beds, and horizontally laminated fine-grained sediment. Six radiocarbon ages ranging from 1800 +/- 210 to 465 +/- 95 14C yr BP on wood indicate that the average rate of delta progradation in the late Holocene has been approximately 290 m per 1000 yr. The lake formed during deglaciation at least 10 000 yr ago and if such a rate of progradation of the delta had prevailed over the entire Holocene, then the delta would be at least three times as extensive as it is today. Thus the rate of delta progradation has varied significantly over the Holocene. We suggest that the rate of delta progradation was at least three times greater when glaciers were in advanced positions. These positions are clearly delimited by Neoglacial moraines, which are within 1-2 km of the exposures studied and within 1 km of modern ice limits. The most recent increase in the rate of delta progradation is

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

OpenAIRE

Lucas Villanueva, Oscar

2012-01-01

El presente trabajo analiza las condiciones y costes del transporte terrestre en tiempos de Felipe II en el ámbito de las relaciones comerciales entre Castilla y el espacio atlántico septentrional, a partir de la información proporcionada por las cartas comerciales del mercader Simón Ruiz. Los datos nos indican que las dificultades geográficas no fueron tan determinantes para el tráfico a través de la Cordillera Cantábrica como se había pensado hasta ahora. El artículo también aborda la cuest...

U-Pb La-ICP-ms geochronology and regional correlation of middle Jurassic intrusive rocks from the Garzon Massif, Upper Magdalena Valley and central cordillera, southern Colombia

International Nuclear Information System (INIS)

Bustamante, Camilo; Cardona, Agustin; Bayona, German; Mora, Andres; Valencia, Victor; Gehrels, George; Vervoort, Jeff

2010-01-01

New U-Pb zircon geochronology from four granitic units sampled along a southeast-northwest transect between the Garzon massif and the Serrania de las Minas (central cordillera), records a middle Jurassic magmatic activity with two different spatio-temporal domains at ca. 189 ma and 180-173 ma. Reconnaissance data suggest that the four granitoids are characterized by mineralogical and geochemical characteristics akin to a continental magmatic arc setting. The new results suggest that the southern Colombian continental margin includes remnants of tectonomagmatic elements formed by the subduction of the Farallon plate under the South American continental margin. This middle Jurassic arc magmatism is part of the broader Andean scale arc province, and is significant for understanding the tectonic and paleogeographic scenario that characterized the Mesozoic tectonic evolution of the northern Andes.

Pedological and mineralogical investigations on a soil-paleosoil sequence within Andosols in the Western Cordillera of the Peruvian Andes (region Laramate, 14.5S)

Science.gov (United States)

Leceta Gobitz, Fernando; Mächtle, Bertil; Schukraft, Gerd; Meyer, Hans-Peter; Eitel, Bernhard

2016-04-01

An integrated research project of environmental sciences focuses on a group of four Andosol profiles in Western flank of the Peruvian southern Andes. Aim of this study is to contribute to the reconstruction of the paleo environmental conditions in the Western Cordillera of the Peruvian Andes. Standard pedological and sedimentological analysis has been conducted in order to identify morphological and geochemical features generated by climatic variations during the middle and late Holocene. Though a provenance analysis of sediments, all potential lithological sources around the town of Laramate are being examined under the scanning electron microscope, in order to find significant mineralogical associations downward the soil-profile. Preliminary results reveal two edaphic cycles within a soil-paleo soil-sequence: a relative poor developed "Ah" topsoil, mostly composed by fine grain sediments, is underlain by a well preserved "2Ah" paleo soil; a "2Bwt" subsoil exhibits signs of alteration and clay translocation; parent material in slight weathered statement at "2C" culminates the sequence. Mineralogical analytical data supports the premise, that materials in the uppermost horizons are relatable to distal geological units of the Western and Eastern Cordillera, therefore also related to other described aeolian archives from the region: "Desert Margin Loess" at the Andean foot-zone and "Mixed Loess" in the Puna grassland. The amphibole varieties Actinolite, Mg-Hornblende and Edenite could be only distinguished within the soil sediments. The fluvial transport to its current position is excluded, insofar mentioned varieties stem from the granodiorites of Coastal Batholite (downstream the study area), and the vulcanites of the Anta und Andahuaylas Formation (eastward the continental divide). References: Eitel, B., et al. (2005). "Geoarchaeological evidence from desert loess in the Nazca-Palpa region, southern Peru : Palaeoenvironmental changes and their impact on Pre

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

Science.gov (United States)

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

2016-12-01

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

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

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Liñán, E.

1988-12-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2013-06-01

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

Magmatismo alcalino del Triásico Superior (Noriense) en el extremo NO de la Rama Aragonesa de la Cordillera Ibérica: Modelo de emplazamiento en relación con fallas sin-sedimentarias

OpenAIRE

Sanz, Tomás; Lago San José, Marceliano; Gil Imaz, Andrés; Pocoví Juan, Andrés; Galé, Carlos

2012-01-01

A través de un estudio lito-estratigráfico y tectónico se pretende deducir el contexto estructural en el que se desarrolló el magmatismo alcalino del Triásico Superior, para el margen nor-occidental de la Rama Aragonesa de la Cordillera Ibérica (Sierra del Moncayo). La reactivación del rift Ibérico y el emplazamiento de al menos dos sills en área estudiada, pudo tener lugar a través de la apertura de un número reducido de fallas normales, con orientación actual Ibérica (NO-S...

Geologic and anthropogenic sources of contamination in settled dust of a historic mining port city in northern Chile: health risk implications

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Joseline S. Tapia

2018-04-01

Full Text Available Chile is the leading producer of copper worldwide and its richest mineral deposits are found in the Antofagasta Region of northern Chile. Mining activities have significantly increased income and employment in the region; however, there has been little assessment of the resulting environmental impacts to residents. The port of Antofagasta, located 1,430 km north of Santiago, the capital of Chile, functioned as mineral stockpile until 1998 and has served as a copper concentrate stockpile since 2014. Samples were collected in 2014 and 2016 that show elevated concentrations of As, Cu, Pb, and Zn in street dust and in residents’ blood (Pb and urine (As samples. To interpret and analyze the spatial variability and likely sources of contamination, existent data of basement rocks and soil geochemistry in the city as well as public-domain airborne dust were studied. Additionally, a bioaccessibility assay of airborne dust was conducted and the chemical daily intake and hazard index were calculated to provide a preliminary health risk assessment in the vicinity of the port. The main conclusions indicate that the concentrations of Ba, Co, Cr, Mn, Ni, and V recorded from Antofagasta dust likely originate from intrusive, volcanic, metamorphic rocks, dikes, or soil within the city. However, the elevated concentrations of As, Cd, Cu, Mo, Pb, and Zn do not originate from these geologic outcrops, and are thus considered anthropogenic contaminants. The average concentrations of As, Cu, and Zn are possibly the highest in recorded street dust worldwide at 239, 10,821, and 11,869 mg kg−1, respectively. Furthermore, the contaminants As, Pb, and Cu exhibit the highest bioaccessibilities and preliminary health risk indices show that As and Cu contribute to elevated health risks in exposed children and adults chronically exposed to dust in Antofagasta, whereas Pb is considered harmful at any concentration. Therefore, an increased environmental awareness and greater

Geologic and anthropogenic sources of contamination in settled dust of a historic mining port city in northern Chile: health risk implications.

Science.gov (United States)

Tapia, Joseline S; Valdés, Jorge; Orrego, Rodrigo; Tchernitchin, Andrei; Dorador, Cristina; Bolados, Aliro; Harrod, Chris

2018-01-01

Chile is the leading producer of copper worldwide and its richest mineral deposits are found in the Antofagasta Region of northern Chile. Mining activities have significantly increased income and employment in the region; however, there has been little assessment of the resulting environmental impacts to residents. The port of Antofagasta, located 1,430 km north of Santiago, the capital of Chile, functioned as mineral stockpile until 1998 and has served as a copper concentrate stockpile since 2014. Samples were collected in 2014 and 2016 that show elevated concentrations of As, Cu, Pb, and Zn in street dust and in residents' blood (Pb) and urine (As) samples. To interpret and analyze the spatial variability and likely sources of contamination, existent data of basement rocks and soil geochemistry in the city as well as public-domain airborne dust were studied. Additionally, a bioaccessibility assay of airborne dust was conducted and the chemical daily intake and hazard index were calculated to provide a preliminary health risk assessment in the vicinity of the port. The main conclusions indicate that the concentrations of Ba, Co, Cr, Mn, Ni, and V recorded from Antofagasta dust likely originate from intrusive, volcanic, metamorphic rocks, dikes, or soil within the city. However, the elevated concentrations of As, Cd, Cu, Mo, Pb, and Zn do not originate from these geologic outcrops, and are thus considered anthropogenic contaminants. The average concentrations of As, Cu, and Zn are possibly the highest in recorded street dust worldwide at 239, 10,821, and 11,869 mg kg -1 , respectively. Furthermore, the contaminants As, Pb, and Cu exhibit the highest bioaccessibilities and preliminary health risk indices show that As and Cu contribute to elevated health risks in exposed children and adults chronically exposed to dust in Antofagasta, whereas Pb is considered harmful at any concentration. Therefore, an increased environmental awareness and greater protective measures

The energy balance on the surface of a tropical glacier tongue. Investigations on glacier Artesonraju, Cordillera Blanca, Perú.

Science.gov (United States)

Juen, I.; Mölg, T.; Wagnon, P.; Cullen, N. J.; Kaser, G.

2006-12-01

The Cordillera Blanca in Perú is situated in the Outer Tropics spanning from 8 to 10 ° South. Solar incidence and air temperature show only minor seasonal variations whereas precipitation occurs mainly from October to April. An energy balance station was installed on the tongue of glacier Artesonraju (4850 m a.s.l.) in March 2004. In this study each component of the energy balance on the glacier surface is analysed separately over a full year, covering one dry and one wet season. During the dry season glacier melt at the glacier tongue is app. 0.5 m we per month. In the wet season glacier melt is twice as much with 1 m we per month. This is due to higher energy fluxes and decreased sublimation during the wet season. With an energy balance model that has already been proved under tropical climate conditions (Mölg and Hardy, 2004) each energy flux is changed individually to evaluate the change in the amount of glacier melt. First results indicate that a change in humidity related variables affects glacier melt very differently in the dry and wet season, whereas a change in air temperature changes glacier melt more constantly throughout the year.

Experiencias de cordillera, ecos de frío: relatos cruzados entre Chile y Quito en el siglo XVI

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Alejandra Vega

2011-01-01

Full Text Available La narración de la secuencia de la conquista del Perú nos enfrenta con la fijación de dos episodios diferentes aunque articulados: la jornada a Quito de Pedro de Alvarado en 1534 y la expedición a Chile de Diego de Almagro, entre 1535 y 1536, que incluyen, ambas, una travesía cordillerana. El presente artículo discute los ecos que pueden rastrearse de los relatos acerca de estas expediciones en un conjunto de obras redactadas en torno a 1550 (Gonzalo Fernández de Oviedo, Francisco López de Gómara, Pedro Cieza de León y Agustín de Zárate. A partir de convergencias y diferencias inesperadas en estos textos, se discute la importancia de la circulación oral de historias entre los conquistadores del Perú. Se plantea que la práctica social de la conversación oral permitió fijar, además de estas historias, una temprana conceptualización cristiana de los límites del Tawantinsuyu. En ella se concibió a Quito y Chile como las marcas fronterizas del espacio recién conquistado, permitiendo que ambos territorios se superpusieran al caracterizarse a partir a un mismo conjunto de imágenes sobre la experiencia de la cordillera.

Rapid Geodetic Shortening Across the Eastern Cordillera of NW Argentina Observed by the Puna-Andes GPS Array

Science.gov (United States)

McFarland, Phillip K.; Bennett, Richard A.; Alvarado, Patricia; DeCelles, Peter G.

2017-10-01

We present crustal velocities for 29 continuously recording GPS stations from the southern central Andes across the Puna, Eastern Cordillera, and Santa Barbara system for the period between the 27 February 2010 Maule and 1 April 2014 Iquique earthquakes in a South American frame. The velocity field exhibits a systematic decrease in magnitude from 35 mm/yr near the trench to convergence accommodated at the subduction interface. Velocity residuals calculated for each model demonstrate that locking on the NZ-SA interface is insufficient to reproduce the observed velocities. We model deformation associated with a back-arc décollement using an edge dislocation, estimating model parameters from the velocity residuals for each forward model of the subduction interface ensemble using a Bayesian approach. We realize our best fit to the thrust-perpendicular velocity field with 70 ± 5% of NZ-SA convergence accommodated at the subduction interface and a slip rate of 9.1 ± 0.9 mm/yr on the fold-thrust belt décollement. We also estimate a locking depth of 14 ± 9 km, which places the downdip extent of the locked zone 135 ± 20 km from the thrust front. The thrust-parallel component of velocity is fit by a constant shear strain rate of -19 × 10-9 yr-1, equivalent to clockwise rigid block rotation of the back arc at a rate of 1.1°/Myr.

"Situación de inmigración" de mujeres sudamericanas en chile: hacia un modelo comprensivo

OpenAIRE

Méndez Caro,Leyla; Cárdenas Castro,Manuel; Gómez Ojeda,Fabiola; Yáñez Yáñez,Susan

2012-01-01

El objetivo de esta investigación fue conocer la situación de inmigración de mujeres sudamericanas en la región de Antofagasta (Chile) y construir un modelo teórico para su análisis. Las participantes de este estudio fueron 19 mujeres de entre 18 y 50 años, residentes en la ciudad de Antofagasta y provenientes de Perú, Bolivia y Colombia. Los principales hallazgos sugirieron un modelo dinámico, en el que se tensiona la identidad social y de género de las mujeres inmigrantes ante la búsqueda d...

On the lag time between internal strain and basement involved thrust induced exhumation: The case of the Colombian Eastern Cordillera

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Mora, Andrès; Blanco, Vladimir; Naranjo, Julian; Sanchez, Nelson; Ketcham, Richard A.; Rubiano, Jorge; Stockli, Daniel F.; Quintero, Isaid; Nemčok, Michal; Horton, Brian K.; Davila, Hamblet

2013-07-01

Thrust sheets accumulate internal strain before they start moving along discrete fault planes. However, there are no previous studies evaluating the time difference between initiation of strain and fault displacement. In this paper we use observations from the Eastern Cordillera of Colombia to evaluate this interval. We utilize multiple thermochronometers and paleothermometers to refine the timing of deformation. Based on these new data we build time-temperature path estimates that together with geometric outcrop-based structural analysis and fluid inclusions allow us to assign relative timing to features associated with strain, such as cleavage, veins and certain types of fractures, and compare that with the timing of thrusting. We find that cleavage was only formed close to maximum paleotemperatures, almost coeval with the onset of thrust-induced denudation by the Late Oligocene. The corresponding structural level of fold-related veins suggest that they were formed later but still when the country rocks were at temperatures higher than 160 °C, mostly during the Early Miocene and still coexisted with the latest stages of cleavage formation. Our data show that the main period of strain hardening was short (probably a few million years) and occurred before first-order basement thrusting was dominant, but was associated with second-order folding.

Seed production differences of the Andean oak Quercus Humboldtii Bonpl. in two Andean forests of the Colombian Eastern Cordillera

International Nuclear Information System (INIS)

Gonzalez Melo, Andres; Parrado Rosselli Angela

2010-01-01

Knowledge of mechanisms of tree species reproduction under natural situations including fruit and seed production patterns is very important for forest management strategies. Considering the influence of abiotic factors such as soil characteristics, humidity and rainfall on fruiting phenology, we studied fruit production patterns of the Andean oak (Quercus humboldtii: Fagaceae) in two forest sites of the Colombian Eastern Cordillera (Cachalu and Patios Altos), under contrasting environmental conditions. At both sites, we monitored monthly fruit production of 15 trees in Cachalu and 11 in Patios Altos using fruit/seed traps placed under the tree crowns. In each site soil cores were extracted below the litter layer 20 cm depth, and soil characteristics and nutrients were analyzed. In general, trees in Cachalu produced more fruits than in Patios Altos, as well as mean fruit mass (wet and dry weight) was significantly higher in Cachalu. At both sites, oak fruiting peaked from April to May, when the highest rainfall occurs. We found positive correlations between fruit production and rainfall one month prior. High phosphorus (P) and potassium (K) were the main variables for explaining the high production. In contrast, high aluminum (Al) contents explained the low production found in Patios Altos. We discuss the importance of including fruit production for oak management strategies, such as restoration and reforestation programs.

Especies de género Lutzomyia (Psychodidae, Phlebotominae en áreas de transmisión de leishmaniasis tegumentaria y visceral en el departamento de Santander, en la cordillera oriental de los Andes colombianos

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Claudia Magaly Sandoval

2006-10-01

Full Text Available Introducción. Los flebótomos desde el punto de vista de salud pública son especialmente conocidos como los únicos insectos vectores de las leishmaniasis y demuestran una interesante biodiversidad en algunas zonas como la cordillera de los Andes en Suramérica. Este estudio presenta las especies de flebótomos organizadas por municipios y zonas endémicas que pueden encontrarse en el departamento de Santander, ubicado sobre la cordillera oriental andina en Colombia. Objetivo. Presentar una actualización del inventario de las especies del género Lutzomyia en el departamento de Santander,señalar la distribución y discutir algunos aspectos de la ecología de las especies de mayor importancia en salud pública. Materiales y métodos. Durante 1998 a 2001 en 12 municipios se realizaron capturas de flebótomos utilizando trampas de luz tipo CDC miniatura, entre las 19:00-6:00 horas, también capturas con cebo humano protegido utilizando aspiradores manuales entre las 18:00-20:00 horas, ocasionalmente aspiración directa sobre troncos de árboles entre las 8:00-11:00 horas y capturas de flebótomos en reposo sobre las paredes en horario diurno. Resultados. Se capturaron un total de 3.972 flebótomos distribuidos en 41 especies; de éstas, 16 especies son nuevos registros para esta región del país. En las zonas consideradas endémicas para leishmaniasis tegumentaria americana se destacaron por su abundancia, presencia en el intradomicilio e importancia epidemiológica L. gomezi, L. trapidoi, L. panamensis, L. ovallesi y L. yuilli yuilli. En las zonas de leishmaniasis visceral americana predominó L. longipalpis.

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

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ANA ALMENDÁRIZ C.

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

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

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Barcelo, Jonathan M; Barcelo, Racquel C

2018-02-01

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

Discovering the Complexity of Capable Faults in Northern Chile

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Gonzalez, G.; del Río, I. A.; Rojas Orrego, C., Sr.; Astudillo, L. A., Sr.

2017-12-01

Great crustal earthquakes (Mw >7.0) in the upper plate of subduction zones are relatively uncommon and less well documented. We hypothesize that crustal earthquakes are poorly represented in the instrumental record because they have long recurrence intervals. In northern Chile, the extreme long-term aridity permits extraordinary preservation of landforms related to fault activity, making this region a primary target to understand how upper plate faults work at subduction zones. To understand how these faults relate to crustal seismicity in the long-term, we have conducted a detailed palaeoseismological study. We performed a palaeoseismological survey integrating trench logging and photogrammetry based on UAVs. Optically stimulated luminescence (OSL) age determinations were practiced for dating deposits linked to faulting. In this contribution we present the study case of two primary faults located in the Coastal Cordillera of northern Chile between Iquique (21ºS) and Antofagasta (24ºS). We estimate the maximum moment magnitude of earthquakes generated in these upper plate faults, their recurrence interval and the fault-slip rate. We conclude that the studied upper plate faults show a complex kinematics on geological timescales. Faults seem to change their kinematics from normal (extension) to reverse (compression) or from normal to transcurrent (compression) according to the stage of subduction earthquake cycle. Normal displacement is related to coseismic stages and compression is linked to interseismic period. As result this complex interaction these faults are capable of generating Mw 7.0 earthquakes, with recurrence times on the order of thousands of years during every stage of the subduction earthquake cycle.

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

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

2017-04-01

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

Recent glacier retreat and lake formation in the Querecocha watershed, Cordillera Blanca, Peru

Science.gov (United States)

López Moreno, J.; Valero-Garces, B.; Revuelto, J.; Azorín-Molina, C.; Bazo, J.; Cochachin, A.; Fontaneda, S.; Mark, B. G.

2013-12-01

In the Andes, and specifically in the Peruvian mountains a marked decrease of the glaciated area has occurred since the end of the Little Ice Age, and it has been accelerated since the last decades of the 20th century. As a result of the glacier retreat new pro-glaciar lakes are originated, and often the area and volume of existing ones increases. The study of these newly-formed lakes and their recent evolution may provide a better understanding of the hydrological and geomorphological evolution of deglaciated areas, and a better evaluation of the risk of glacial lakes outburst floods (GLOFS). In this work, we use 26 annual Landsat Thematic Mapper images from 1975 to 2010 to determine changes of the glaciated surface, snow line elevation and lakes formation in the headwaters of the Querecocha watershed in Cordillera Blanca (Perú). We also present the information derived from 10 short sediment cores (up to 50 cm long) retrieved along several transects in Yanamarey Lake. Both data sets inform of the sediment yield and lake development in recently deglaciated environments of the Andes. Results demonstrate that only one third of the surface covered by ice in 1975 remained in 2010. In this period, snowline has shifted up more than 100 meters in elevation in both, Yanamarey North and South areas respectively. At the same time, new lakes have been formed very quickly in these deglaciated areas. Preliminary 137Cs dating of Yanamarey sediment core indicates that at least the top 50 cm of the lake sequence deposited after 1960. This is coherent with the Landsat image of 1975 that showed the current surface of the lake still covered by ice. The high sediment rate (> 1 cm/yr) in the lake demonstrates the very high sediment yield in these geomorphically active settings. The sediment cores are composed of cm-thick sequences defined by grain-size (silt-clay) common in proglacial lakes reflecting the variability of hydrological response associated to the glacier retreat in the

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

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Benavente Herrero, J.

1985-08-01

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

NUEVA ESPECIE DE RANA BROMELÍCOLA DEL GÉNERO PRISTIMANTIS (AMPHIBIA: CRAUGASTORIDAE, MESETA DE LA CORDILLERA DEL CÓNDOR, ECUADOR

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JORGE BRITO M.

Full Text Available RESUMEN Describimos una especie pequeña de rana bromelícola del género Pristimantis (longitud rostro-cloaca en hembras 20.3-23.3 mm; en machos 16.1-17.4 mm, proveniente de una remota meseta de arenisca de la Cordillera del Cóndor, en el sureste de Ecuador, con un rango altitudinal de 2.045-2.860 m. Una filogenia en base a secuencias de ADN (genes mitocondriales y nucleares muestra que la nueva especie forma parte del grupo P. orestes y está más cercanamente relacionada con una especie de Pristimantis aún no descrita de la vertiente sur oriental ecuatoriana. Difiere de sus congéneres de Ecuador, por su coloración dorsal y ventral predominantemente negra; superficie palmar amplia y robusta con dedos cortos y gruesos; presencia de un surco profundo y amplio extendido desde la base anterior del I dedo manual hasta la base posterior del tubérculo palmar; tubérculos subarticulares divididos, tubérculos supernumerarios agrandados y con granulaciones pequeñas. Todos los individuos registrados estuvieron en bromelias terrestres. Las llamadas son cortas, de frecuencia modulada, conformada por una nota con duración de 5-15 ms. Los insectos representaron el 80% de la dieta de la especie nueva.

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

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O. Wigmore

2017-11-01

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

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

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

2015-12-01

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

Morbid condition involving cardio-vascular, broncho-pulmonary, digestive and neural lesions in children and young adults after dietary arsenic exposure

Energy Technology Data Exchange (ETDEWEB)

Zaldivar, R.

1980-02-01

An investigation on the relationship between dietary arsenic exposure and cardiovascular diseases was made. In Antofagasta Commune, northern Chile, since 1955 arsenic has polluted public drinking water. This environmental contamination is of geological origin. The concentration of arsenic in drinking water for the 1955 to 1970 period was 0.5980 ppM. In the period June 1970 to March 1972, the concentration decreased to 0.0815 ppM due to a water filtration plant which started operating in May 1970. Greater Santiago showed 0.00 ppM of arsenic in drinking water. Amongst 10 autopsied patients with chronic arsenical dermatosis from Antofagasta Commune, 9 showed marked fibrous intimal thickening of the arterial wall and/or restricted lumen of the left coronary artery, 2 of these 9 also exhibiting myocardial infarction. Of the 10 patients, 7 developed cardiomegaly, which was related to chronic exposure to dietary arsenic. Two series of patients with myocardial infarction under 40 years of age, one from Antofagasta Commune, the other from greater Santiago (not exposed to arsenic) were compared. The Yates corrected chi 2 value being 11.7776. The difference was statistically highly significant. In Antofagasta Commune, the number of cases which had myocardial infarction with chronic arsenical dermatosis were compared with the cases which showed, myocardial infarction without chronic arsenical dermatosis. The Yates corrected chi 2 value was 13.0395. A highly significant difference was detected. Children from the two cities were also compared. The number of cases with myocardial infarction showed a significant difference; Fisher's exact test yielded a P approximately equal to 0.004944, the Yates corrected chi 2 value being 20.7311. The number of children with systemic occlusive arterial disease from the two cities also exhibited a highly significant difference.

Temperature effects on zoeal morphometric traits and intraspecific variability in the hairy crab Cancer setosus across latitude

Science.gov (United States)

Weiss, Monika; Thatje, Sven; Heilmayer, Olaf

2010-06-01

Phenotypic plasticity is an important but often ignored ability that enables organisms, within species-specific physiological limits, to respond to gradual or sudden extrinsic changes in their environment. In the marine realm, the early ontogeny of decapod crustaceans is among the best known examples to demonstrate a temperature-dependent phenotypic response. Here, we present morphometric results of larvae of the hairy crab Cancer setosus, the embryonic development of which took place at different temperatures at two different sites (Antofagasta, 23°45' S; Puerto Montt, 41°44' S) along the Chilean Coast. Zoea I larvae from Puerto Montt were significantly larger than those from Antofagasta, when considering embryonic development at the same temperature. Larvae from Puerto Montt reared at 12 and 16°C did not differ morphometrically, but sizes of larvae from Antofagasta kept at 16 and 20°C did, being larger at the colder temperature. Zoea II larvae reared in Antofagasta at three temperatures (16, 20, and 24°C) showed the same pattern, with larger larvae at colder temperatures. Furthermore, larvae reared at 24°C, showed deformations, suggesting that 24°C, which coincides with temperatures found during strong EL Niño events, is indicative of the upper larval thermal tolerance limit. C. setosus is exposed to a wide temperature range across its distribution range of about 40° of latitude. Phenotypic plasticity in larval offspring does furthermore enable this species to locally respond to the inter-decadal warming induced by El Niño. Morphological plasticity in this species does support previously reported energetic trade-offs with temperature throughout early ontogeny of this species, indicating that plasticity may be a key to a species’ success to occupy a wide distribution range and/or to thrive under highly variable habitat conditions.

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

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

2009-12-01

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

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

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Carolina Garcia

2004-12-01

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

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

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Soria, J. M.

1994-08-01

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

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

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Javier Valera-Leal

2011-03-01

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

IDRC in Chile

International Development Research Centre (IDRC) Digital Library (Canada)

occupied by Morocco). SENEGAL. GUINEA BISSAU. CHILE. Santiago. %. 0. 300 km. ARGENTINA. BOLIVIA. PERU. Arica. Punta Arenas . Puerto Montt . South. Pacific. Ocean. South. Atlantic. Ocean. Antofagasta. Coquimbo. Valparaiso. Concepcíon.

Short-and-long-term Slip Rates Along the Carboneras Fault in the Betic Cordillera, Spain

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Khazaradze, G.; López, R.; Pallàs, R.; Ortuño, M.; Bordonau, J.; Masana, E.

2017-12-01

We present the new results from our long-standing studies to understand the geodynamic behavior of the Carboneras fault, located in the SE Betic Cordilleras of Spain. Specifically, we quantify the geodetic and geologic slip rates for the onland section of the fault. As a result of our previous GPS observations, we have been able to confirm the continuing tectonic activity of the Carboneras fault: we were able to quantify that the geodetic slip rate of the fault equals 1.3±0.2 mm/yr, expressed mainly as a left-lateral strike slip motion (Echeverria et al., 2015). In autumn 2017, with the purpose of revealing a detailed nature of the crustal deformation and its partitioning between different structures, 3 new continuous GPS stations will be established along the fault-perpendicular profile. In addition, since summer 2016, we have conducted surveys of the nearby CuaTeNeo and IGN Regente campaign points. We have also established and measured several new geodetic points in the vicinity of the fault, with the aim of increasing the spatial coverage around it. The GPS measured, short-term slip rates are in surprising agreement with the estimates of the long-term, geologic slip rates based on paleoseismic studies, which indicate a minimum strike-slip rate of 1.31 mm/yr and dip-slip rate of 0.05 mm/yr since 110.3 ka (Moreno et al. 2015). In order to increase the paleoseismic event database, several new sites have been identified along the fault, where further paleoseismic trenching surveys will be performed within the coming year or two. At the site of Tostana, located at the central part of the fault, in winter 2017 seven trenches have been opened and clear evidence of past earthquakes has been encountered. These new data, combined with the findings of the recent geomorphological study of river offsets (Ferrater, 2016) and new GPS observations, should improve the reliability of the existent deformation data and therefore, will help to better understand the seismic hazard

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

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José Piquer

2010-01-01

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

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

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

2014-05-01

Sierra Nevada uplift and with original NE-SW normal left-lateral fault system associated with a compatible ESE-WNW normal fault system. The asymmetrical morphologies of the two delta-fan bodies confirm this configuration as tectonic induced deposits. References Braga, J.C., Martín, J.M. and Alcalá, B. (1990). Coral reefs in coarse-terrigenous sedimentary environments (Upper Tortonian, Granada Basin, southern Spain). Sedimentary Geology, 66, pp 135-150. Clark, S.J.P.and Dempster, T.J. (2009). The record of tectonic denudation and erosion in an emerging orogen: an apatite fission-track study of the Sierra Nevada, southern Spain. Journal of the Geological Society, London, Vol. 166, pp. 87-100. Dabrio, C.J., Fernández, J., Peña, J., Ruíz-Bustos, A. y Sanz de Galdeano, C. (1978). Rasgos sedimentarios de los conglomerados miocénicos del borde noreste de la Depresión de Granada. Estudios Geológicos, 34, pp 89-97. García-García, F., Fernández, J., Viseras, C. and Soria, J.M. (2006). Architecture and sedimentary facies evolution in a delta stack controlled by fault growth (Betic Cordillera, southern Spain, late Tortonian). Sedimentary Geology, 185, pp. 79-92. García-García, F., Viseras, C. and Fernández, J. (1999). Organización secuencial de abanicos deltaicos controlados por la tectónica (Tortoniense superior, cuenca de Granada, Cordillera Bética). Rev. Soc. Geol. España, 12 (2): 199-208.

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

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

2002-05-01

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

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

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

2014-05-01

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

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

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McPhee, James; Mengual, Sebastian; MacDonell, Shelley

2017-04-01

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

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

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

2014-12-01

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

The isolation of the temperature effect on branched GDGT distribution in an elevation transect of the Eastern Cordillera, Colombia

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Anderson, V. J.; Shanahan, T. M.; Saylor, J.; Horton, B. K.

2012-12-01

Recently, the distribution of branched GDGT's (glycerol dialkyl glycerol tetraethers) has been proposed as a proxy for temperature and pH in soils via the MBT/CBT index, and has been used to reconstruct past temperature variations in a number of settings ranging from marine sediments to loess deposits and paleosols. However, empirical calibrations of the MBT/CBT index against temperature show significant scatter, leading to uncertainties as large as ±2 degrees C . In this study we seek to add to and improve upon the existing soil calibration using a new set of samples spanning a large elevation (and temperature) gradient in the Eastern Cordillera of Colombia. At each site we buried temperature loggers to constrain the diurnal and seasonal temperature experienced by each soil sample. Located only 5 degrees north of the equator, our sites experience a very small seasonal temperature variation - most sites display an annual range of less than 4 degrees C. In addition, the pH of all of the soils is almost invariant across the transect, with the vast majority of samples having pH's between 4 and 5. This dataset represents a "best-case" scenario - small variations in seasonal temperature, pH, and well-constrained instrumental data - which allow us to examine the brGDGT-temperature relationship in the absence of major confounding factors such as seasonality and soil chemistry. Interestingly, the relationship between temperature and the MBT/CBT index is not improved using this dataset, suggesting that these factors are not the cause of the anomalous scatter in the calibration dataset. However, we find that using other parameterizations for the regression equation instead of the MBT and CBT indices, the errors in our temperature estimates are significantly reduced.

Influencia de un bloque rígido en un sistema de fallas de rumbo: modelamiento análogo Influence of a rigid block in a strike-slip fault system: analogue modelling

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Thierry Nalpas

2011-01-01

Full Text Available En este trabajo se presenta un estudio de modelamiento análogo sobre la naturaleza, geometría y cinemática de la deformación a lo largo de fallas de rumbo dada la presencia de un bloque rígido en su trayectoria de deformación. Los modelos análogos están apropiadamente escalados considerando las características reológicas de los materiales que se desean contrastar en la deformación. Dos grandes parámetros fueron probados: la configuración del bloque rígido, variando su forma y tamaño, y el monto del desplazamiento. Los resultados experimentales muestran el desarrollo de rotaciones, fallas y pliegues como producto de la presencia de un bloque rígido en la trayectoria de falla. Los diversos casos geométricos probados pueden ser empleados para su comparación con sistemas de fallas de rumbo en los cuales existen diferencias litológicas de comportamiento reológico diferencial, como por ejemplo el caso del 'Núcleo rígido de Limón Verde' al sur de Chuquicamata, ubicado en la trayectoria del sistema de fallas de Domeyko.This work addresses the kinematic effects of a rigid block in strike-slip systems by using analogue models. The experiments (size, behaviour of materials were scaled down in order to represent deformation of the tested rheologic contrast conditions in deformation. Two main parameters were tested: the configuration of the rigid block, changing its form and size, and the amount of displacement. The experiments evidenced the development of rotations, faults and folds along the fault trajectory, as resulting from the presence of the rigid block during the deformation. Testing of diverse geometric situations may be used for comparison to strike-slip fault systems in which different lithologies and rheologic behaviour exist, for example, presence of the 'Limón Verde rigid core' along the Domeyko fault system, just south of Chuquicamata.

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

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Pedro Busquets

2013-01-01

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

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

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Meléndez, A.

1987-08-01

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

Emergy evaluation of benthic ecosystems influenced by upwelling in northern Chile: Contributions of the ecosystems to the regional economy

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Emergy evaluations of three benthic ecosystem networks found in Mejillones, Antofagasta and Tongoy Bays, located on the coast of northern Chile, were carried out with the intent of documenting the contributions of these coastal ecosystems to the economy. The productivity of these...

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

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Javier Valera-Leal

2011-03-01

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

Playas artificiales de Antofagasta. Un Proyecto Bicentenario

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Gino Pérez Lancellotti

2007-05-01

El litoral, por su naturaleza rocosa carece de playas naturales por lo que a partir del año 2000 las autoridades a cargo del desarrollo urbano, asumieron la tarea de dotar a la ciudad de tres grandes playas artificiales. Para lograr su propósito se construyeron defensas costeras, se hicieron desrocados y se rellenó algunos sectores con arena de empréstito, con interesantes logros ambientales.

Precise Surface Exposure Dating of Early Holocene and Little Ice Age Moraines in the Cordillera Vilcabamba of Southern Peru

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

2008-12-01

We have established precise ages of two glacial events in the tropical Andean highlands of southern Peru. The field site is located on the flanks of Nevado Salcantay (6271 m asl; 13°20'S latitude), the highest peak in the Cordillera Vilcabamba. A two-fold sequence of nested lateral and end moraines was mapped in a glacial trough emanating from the south face of Salcantay. Well-defined outer and inner moraines were deposited by valley glaciers that terminated 5 km and 3 km, respectively, from their head on the Salcantay massif. Cosmogenic 10Be surface exposure dating of boulders on the outer (n = 7) and inner (n = 7) moraine crests expands upon initial age control for these deposits and improves substantially on the precision of earlier 10Be measurements. The new results yield mean ages of 9.0 ± 0.3 ka for the outer moraine and 195 ± 24 years for the inner moraine, corresponding to glacial events during the early and latest Holocene. These ages are derived using the CRONUS-Earth 10Be exposure age calculator with Lal-Stone production rate scaling and the default height-pressure relationship. The inner moraine age correlates with the timing of the Little Ice Age as defined from northern mid- and high latitude records, and indicates considerable expansion of glaciers heading on Nevado Salcantay during this climatic minimum. Recent geomorphic mapping has identified similar sequences of moraines in adjacent drainages on and near Salcantay, suggesting a broader regional signal of two prominent Holocene glacial events in this segment of the southern Peruvian Andes; 10Be dating of these additional moraines is underway. Our new glacier chronologies complement ice core and lacustrine paleoclimate records in the vicinity, thereby increasing spatial and temporal coverage for identifying patterns of climate change in the tropical Andes during the Holocene. Apart from their paleoclimatic significance, the results also demonstrate a newly- developed capability of 10Be exposure

Taxonomic and geographic novelties in the genus Plantago (Plantaginaceae) in Chile, including the description of a new species

DEFF Research Database (Denmark)

Hassemer, Gustavo; Shipunov, Alexey; Rønsted, Nina

2018-01-01

We present taxonomic and geographic novelties in the genus Plantago from Chile. More specifically, we describe P. nebularis, a new species endemic to Cerro Moreno, Antofagasta region, and propose P. zoellneriana, a new name for P. sericea subsp. araucana. We also lectotypify the name P. sericea, ...

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

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Ursula Thiemer-Sachse

2003-04-01

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

"Situación de inmigración" de mujeres sudamericanas en chile: hacia un modelo comprensivo

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Leyla Méndez Caro

2012-01-01

Full Text Available El objetivo de esta investigación fue conocer la situación de inmigración de mujeres sudamericanas en la región de Antofagasta (Chile y construir un modelo teórico para su análisis. Las participantes de este estudio fueron 19 mujeres de entre 18 y 50 años, residentes en la ciudad de Antofagasta y provenientes de Perú, Bolivia y Colombia. Los principales hallazgos sugirieron un modelo dinámico, en el que se tensiona la identidad social y de género de las mujeres inmigrantes ante la búsqueda de coherencia dentro de sus espacios vitales. Advertimos en la interacción con la sociedad receptora, la imposición de nuevas categorías sociales a cambio de integración basada en la asimilación. No obstante, también se observan formas de resistencia frente a dicho proceso.

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

OpenAIRE

Oscar LUCAS VILLANUEVA

2012-01-01

El presente trabajo analiza las condiciones y costes del transporte terrestre en tiempos de Felipe II en el ámbito de las relaciones comerciales entre Castilla y el espacio atlántico septentrional, a partir de la información proporcionada por las cartas comerciales del mercader Simón Ruiz. Los datos nos indican que las dificultades geográficas no fueron tan determinantes para el tráfico a través de la Cordillera Cantábrica como se había pensado hasta ahora. El artículo también aborda la cuest...

Emerging Glacial Lakes in the Cordillera Blanca, Peru: A Case Study at Arteson Glacier

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Chisolm, R. E.; Mckinney, D. C.; Gomez, J.; Voss, K.

2012-12-01

Tropical glaciers are an essential component of the water resources systems in the mountainous regions where they are located, and a warming climate has resulted in the accelerated retreat of Andean glaciers in recent decades. The shrinkage of Andean glaciers influences the flood risk for communities living downstream as new glacial lakes have begun to form at the termini of some glaciers. As these lakes continue to grow in area and volume, they pose an increasing risk of glacial lake outburst floods (GLOFs). Ice thickness measurements have been a key missing link in studying the tropical glaciers in Peru and how climate change is likely to impact glacial melt and the growth of glacial lakes. Ground penetrating radar (GPR) has rarely been applied to glaciers in Peru to measure ice thickness, and these measurements can tell us a lot about how a warming climate will affect glacier mass balance. This study presents GPR data taken in July 2012 at the Arteson glacier in the Cordillera Blanca, Peru. A new lake has begun to form at the terminus of the Arteson glacier, and this lake has key features, including overhanging ice and loose rock likely to create landslides, that could trigger a catastrophic GLOF if the lake continues to grow. This new lake is part of a series of three lakes that have formed below the Arteson glacier. The two lower lakes, Artesonraju and Paron, are much larger so that if there were an avalanche or landslide into the new lake below Arteson glacier, the impact could potentially be more catastrophic than a GLOF from one single lake. Estimates of how the lake mass balance is likely to evolve due to the retreating glacier are key to assessing the flood risk from this dynamic three-lake system. Because the glacier mass balance and lake mass balance are closely linked, the ice thickness measurements and measurements of the bed slope of the Arteson glacier and underlying bedrock give us a clue to how the lake is likely to evolve. GPR measurements of

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

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Alejandra Vega

2011-11-01

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

Deciphering shallow paleomagnetic inclinations: 1. Implications from correlation of Albian volcanic rocks along the Insular/Intermontane Superterrane boundary in the southern Canadian Cordillera

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Haskin, M. L.; Enkin, R. J.; Mahoney, J. B.; Mustard, P. S.; Baker, J.

2003-04-01

Geologic and paleomagnetic data lead to two contradictory hypotheses regarding the paleoposition of the Insular and Intermontane Superterranes that presently constitute the western Canadian Cordillera. Paleomagnetic data from the Insular and Intermontane superterranes suggest a southerly origin coinciding with the latitude of Mexico and the northwest United States, respectively, during the mid-Cretaceous. Geologic evidence points to a northerly origin for these same tectonic entities during this period; both models cannot be correct. Geologic and paleomagnetic data from the Empire Valley-Churn Creek area in south central British Columbia (51.5°N, 122.5°W) are critical to resolving these contradictory hypotheses. Late Cretaceous rocks correlated to the Insular Superterrane with large paleomagnetic displacements unconformably overlie mid-Cretaceous rocks correlative to the Spences Bridge Group of the Intermontane Superterrane. We provide paleomagnetic evidence of this correlation based on similar magnetic properties, opaque mineral assemblages, demagnetization behavior, fold test results, mean inclinations, clockwise vertical axes rotations, and statistically indistinguishable paleomagnetic poles and displacement estimates. This correlation and the observed geologic relationships in the Empire Valley-Churn Creek area indicate that the Insular and Intermontane Superterranes were linked by the mid-Cretaceous. Sites from the two previous Spences Bridge Group studies are combined with their correlatives in the Empire Valley-Churn Creek area to give 81 sites that yield a paleomagnetic pole of 60.5°N, 304.5°E, dp = 3.7°, dm = 5.5° which corresponds to 1050 ± 450 km of displacement from the south. This new displacement estimate suggests that the Spences Bridge arc formed at the latitude of southern Oregon during the mid-Cretaceous.

Reestablecimiento de Choromytilus chorus (Molina, 1782 (Bivalvia: Mytilidae en el norte de Chile Reestablishment of Choromytilus chorus (Molina, 1782 (Bivalvia: Mytilidae in northern Chile

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Miguel Avendaño

2011-07-01

Full Text Available Hasta fines del siglo pasado no existían registros de la presencia de Choromytilus chorus al norte de los 23°S, pese a antecedentes que señalaban su existencia en épocas pasadas. Ciertos cambios relacionados con las masas de agua costeras de esta zona, habrían generado la ausencia o escasez que presentaba el entorno costero actual. Sin embargo, hace una década atrás, su presencia en el norte de Chile, comienza a tener connotación pesquera. En el presente trabajo se confirma su reestablecimiento en las regiones de Antofagasta y Tarapacá, mediante prospecciones realizadas en seis lugares donde se registró su presencia, así como mediante la captación de semilla en colectores suspendidos. Se indica interacción con Aulacomya ater, a la cual ha desplazado a estratos más profundos, mientras que su reestablecimiento, iniciado en las regiones de Atacama y Antofagasta, y que se amplió posteriormente a la región de Tarapacá; permite postular la hipótesis que la dinámica de estos bancos, respondería a una estructura de metapoblación, dado el sistema de corrientes y vientos que predominan en la zona norte, permitiendo la advección larval de poblaciones existentes en la región de Coquimbo.Despite indications of its presence in past ages, until the end of the last century, no records showed Choromytilus chorus north of 23°S. Certain changes related to coastal water masses in the zone could be responsible for the present lack or scarcity of this species in the coastal area. However, a decade ago, this species appeared in northern Chile in the context of fisheries. This study confirms the re-establishment of C. chorus in the Antofagasta and Tarapaca regions through surveys at six sites where the species had been registered and spat collection using suspended collectors. This species has interacted with Aulacomya ater, displacing it towards deeper habitats. The re-establishment of C. chorus began in the Atacama and Antofagasta regions and

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

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

2005-01-01

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

The tectonothermal evolution of the Venezuelan Caribbean Mountain System: 40Ar/39Ar age insights from a Rodinian-related rock, the Cordillera de la Costa and Margarita Island

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Fournier, Herbert W.; Lee, James K. W.; Urbani, Franco; Grande, Sebastián

2017-12-01

The Caribbean Mountain System in Venezuela contains rocks formed at high-pressure/low-temperature (HP/LT) conditions by the Cretaceous-Paleocene oblique collision occurred between the Caribbean and South American plates and involving Rodinian-related blocks. 40Ar/39Ar dating of rocks from the Cordillera de la Costa and Margarita Island has constrained key pre- and syntectonothermal events associated with the emplacement of this system. In a Rodinian marble, two phlogopite crystals of different grain sizes yield plateau ages of 888 ± 4 Ma and 874 ± 4 Ma. These results are interpreted as cooling ages after a major anorthosite-mangerite-charnockite-granite-suite intrusion at 920 Ma related to the break-up of Rodinia along the Amazonian-Baltica collisional zone - the Putumayo Orogen. Current plate reconstructions during the Neoproterozoic and previous age results indicate a correlation between the anorthositic complexes located in northwestern Venezuela (Yumare Complex) and southern Norway (Rogaland Complex), suggesting a similar tectonic setting during orogenic relaxation along the Amazonian and Baltica suture. A temperature-time path based on calculated Ar-closure temperatures of phlogopite indicates rapid cooling of 14 ± 4 °C Ma-1 from 920 Ma to 888 Ma, and a very slow to almost isothermal cooling of 4 ± 2 °C Ma-1 from 888 Ma to 874 Ma. On Margarita Island, magnesiohornblende and (alumino) barroisite from HP/LT rocks and muscovite from a leucocratic rock that was intruded before the HP/LT event yield identical ages within error at c. 54-47 Ma, consistent with previous dating results across the island utilizing different isotopic systems. The close association of these rocks and the Manzanillo Shear Zone indicates a main pathway for Ca-rich, 40Ar-free and hot fluids that locally raised the ambient T of the already exhumed and juxtaposed rock units. These fluids crystallized new hornblende and muscovite and thermally reset barroisite. This fluid activity event

An autochthonous geological model for the eastern Andes of Ecuador

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Pratt, Warren T.; Duque, Pablo; Ponce, Miguel

2005-04-01

We describe a traverse across the Cordillera Real and sub-Andean Zone of Ecuador, poorly known areas with very little detailed mapping and very little age control. The spine of the Cordillera comprises deeply eroded Triassic and Jurassic plutons, the roots of a major arc, emplaced into probable Palaeozoic pelites and metamorphosed volcanic rocks. The W flank comprises a Jurassic (?) submarine basaltic-andesitic volcanic sequence, which grades up into mixed Jurassic/Cretaceous volcanic and sedimentary rocks of the Inter-Andean Valley. The sub-Andean Zone, on the E flank of the Cordillera, comprises a newly recognized Cretaceous basin of cleaved mudrocks, quartz arenites and limestones. East of the syndepositional Cosanga Fault, the Cretaceous basin thins into a condensed sequence that is indistinguishable from the rocks of the adjacent hydrocarbon-bearing Oriente Basin. The principal penetrative deformation of the Cordillera Real was probably latest Cretaceous/Palaeocene. It telescoped the magmatic belts, but shortening was largely partitioned into the pelites between plutons. The plutons suffered inhomogenous deformation; some portions completely escaped tectonism. The pelites conserve two foliations. The earliest comprises slaty cleavage formed under low- or sub-greenschist conditions. The later is a strong schistosity defined by new mica growth. It largely transposed and obliterated the first. Both foliations may have developed during a single progressive deformation. We find inappropriate recent terrane models for the Cordillera Real and sub-Andean Zone of Ecuador. Instead we find remarkable similarities from one side of the Cordillera to the other, including a common structural history. In place of sutures, we find mostly intrusive contacts between major plutons and pelites. Triassic to Cretaceous events occurred on the autochthonous western edge of the Archaean Guyana Shield. The latest Cretaceous-Paleocene deformation is interpreted as the progressive

Multiproxy records of Holocene climate and glacier variability from sediment cores in the Cordillera Vilcabamba of southern Peru

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Schweinsberg, A. D.; Licciardi, J. M.; Rodbell, D. T.; Stansell, N.; Tapia, P. M.

2012-12-01

Sediments contained in glacier-fed lakes and bogs provide continuous high-resolution records of glacial activity, and preserve multiproxy evidence of Holocene climate change. Tropical glacier fluctuations offer critical insight on regional paleoclimatic trends and controls, however, continuous sediment records of past tropical climates are limited. Recent cosmogenic 10Be surface exposure ages of moraine sequences in the Cordillera Vilcabamba of southern Peru (13°20'S latitude) reveal a glacial culmination during the early Holocene and a less extensive glaciation coincident with the Little Ice Age of the Northern Hemisphere. Here we supplement the existing 10Be moraine chronology with the first continuous records of multiproxy climate data in this mountain range from sediment cores recovered from bogs in direct stratigraphic contact with 10Be-dated moraines. Radiocarbon-dated sedimentological changes in a 2-meter long bog core reveal that the Holocene is characterized by alternating inorganic and organic-rich laminae, suggesting high-frequency climatic variability. Carbon measurements, bulk density, and bulk sedimentation rates are used to derive a record of clastic sediment flux that serves as a proxy indicator of former glacier activity. Preliminary analyses of the bog core reveal approximately 70 diatom taxa that indicate both rheophilic and lentic environments. Initial results show a general decrease in magnetic susceptibility and clastic flux throughout the early to mid-Holocene, which suggests an interval of deglaciation. An episode of high clastic flux from 3.8 to 2.0 ka may reflect a late Holocene glacial readvance. Volcanic glass fragments and an anomalous peak in magnetic susceptibility may correspond to the historical 1600 AD eruption of Huaynaputina. Ten new bog and lake sediment cores were collected during the 2012 field expedition and analytical measurements are underway. Ongoing efforts are focused on analyzing diatom assemblage data, developing

Ionospheric Scintillation Effects on GPS

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Steenburgh, R. A.; Smithtro, C.; Groves, K.

2007-12-01

. Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 degrees of the geomagnetic equator. As GPS applications and users increases, so does the potential for detrimental impacts from scintillation. We examined amplitude scintillation data spanning seven years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/Americas longitudinal sector at as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K.; in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. We examine diurnal, seasonal and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

Records and reputations : everyday politics of a Philippine Development NGO

NARCIS (Netherlands)

Hilhorst, D.

2000-01-01

This study looks into the working of policies, practices and accountability of NGOs. It is based on fieldwork with one development NGO in the Cordillera of the Philippines: the Cordillera Women NGO, or CWNGO (a pseudonym). Through this study I wanted to find out why certain groups of actors

"The Bridge" from Earthscope to EarthsCAN to Maintain North American Geoscience Momentum

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Boggs, K. J. E.; Hyndman, R. D.; Eaton, D. W. S.

2016-12-01

"The Bridge", of seismic instruments across the Yukon-western NWT from the USArray-Alaska extending from the Pacific Ocean to the Beaufort Sea, is a possible proof of concept for the new EarthsCAN research initiative. The proposal is to fill gaps between the USArray-Alaska seismic stations, the McKenzie Mtn Earthscope Project, seismic sites of the Geological Survey of Canada, the Yukon Geological Survey, the University of Ottawa and other industry/government consortia. Workshop results defined important northern Cordillera questions. The Yukon Stable Block (YSB) is underlain in part by the Paleoproterozoic Wernecke Supergroup (not exposed elsewhere in the Cordillera). Cretaceous-Tertiary structures are deflected around the YSB suggesting stronger internal crust in the YSB. New GPS observations (Alaska and NW Canada) indicate that as the Yakutat block is colliding with North America that the Elias block is rotating counterclockwise, and the Alaska panhandle rotating clockwise into North America. Seismic activity also extends 800 km from the plate boundary to current deformation in the Mackenzie and Richardson Mountains. A model to explain neotectonic deformation proposes a strong upper crust, decoupled from the underlying mantle due to elevated basal temperatures, which is pushed against the plate boundary and transmits stresses throughout the Cordillera. Resolving these questions requires high-resolution seismic velocity models of the crust and mantle, dense GPS velocity fields, as well as mapping active faults in the Mackenzie Mountains and across the Cordillera via Lidar images and paleoseismic trenching. The transition from the actively deforming northern Cordillera to the relatively aseismic northern Rockies across a lithospheric-scale transfer zone inherited from former passive margins, similar to the one bounding the YSB in the north, may be an important characteristic of modern Cordilleras that controls tectonic activity.

A new minute Andean Pristimantis (Anura: Strabomantidae from Venezuela

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César L. Barrio-Amorós

2012-12-01

Full Text Available A new species of Pristimantis is described from the Venezuelan Andes. The new species is the smallest in its genus known in Venezuela and belongs to the Pristimantis unistrigatus Group. It differs from the rest of Venezuelan Andean congeners in body size (mean male SVL < 21.3 mm, female SVL < 26.3 mm, expanded discs on fingers and toes, absence of dorsolateral folds, and a distinctivecall consisting in 2–5 cricket-like short notes. The new species inhabits the southwestern part of the Cordillera de Mérida in Venezuela and the Venezuelan side of the Cordillera Oriental deColombia, and could be present on the Colombian portion of the cordillera as well.

Una nueve especie del género Killipia (Melastomatacea

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Ruiz Rodgers Natalia

1997-06-01

Full Text Available A new species of the genus Killipia (Melastomataceae from the "Serranía de los Paraguas" in the Cordillera Occidental of Colombia, is described and illustrated.Se describe e ilustra una nueva especie del género Killipia (Melastomataceae, de la Serranía de los Paraguas en la Cordillera Occidental de Colombia.

Three-dimensional models of P wave velocity and P-to-S velocity ratio in the southern central Andes by simultaneous inversion of local earthquake data

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Graeber, Frank M.; Asch, Günter

1999-09-01

The PISCO'94 (Proyecto de Investigatión Sismológica de la Cordillera Occidental, 1994) seismological network of 31 digital broad band and short-period three-component seismometers was deployed in northern Chile between the Coastal Cordillera and the Western Cordillera. More than 5300 local seismic events were observed in a 100 day period. A subset of high-quality P and S arrival time data was used to invert simultaneously for hypocenters and velocity structure. Additional data from two other networks in the region could be included. The velocity models show a number of prominent anomalies, outlining an extremely thickened crust (about 70 km) beneath the forearc region, an anomalous crustal structure beneath the recent magmatic arc (Western Cordillera) characterized by very low velocities, and a high-velocity slab. A region of an increased Vp/Vs ratio has been found directly above the Wadati-Benioff zone, which might be caused by hydration processes. A zone of lower than average velocities and a high Vp/Vs ratio might correspond to the asthenospheric wedge. The upper edge of the Wadati-Benioff zone is sharply defined by intermediate depth hypocenters, while evidence for a double seismic zone can hardly be seen. Crustal events between the Precordillera and the Western Cordillera have been observed for the first time and are mainly located in the vicinity of the Salar de Atacama down to depths of about 40 km.

Lg and Other Regional Phases in South America

Science.gov (United States)

1991-10-23

de la dispersi6n de ondas superficiales, Tesis de Grado, Universidad de Chile, Santiago, Chile. Herrmann, R. B. (1980). Q estimates...Altiplanoa; Cordillera de la Costa; Pianicie Costera; Cuenca Superior del Amazonias ; Lianuras Chaco-Benianas; Escudo Brasilego y el La cordillera de ...BrasileRo a partir de la duspersi6r de las ondas superficiales, resis de Grado, Universidad de Chile,

Detrital zircon typology and U/Pb geochronology for the Miocene Ladrilleros-Juanchaco sedimentary sequence, Equatorial Pacific (Colombia): New constraints on provenance and paleogeography in northwestern South America

Energy Technology Data Exchange (ETDEWEB)

Osorio-Granada, E.; RESTREPO-MORENO, S.A.; MUÑOZ-VALENCIA, J.A.; TREJOS-TAMAYO, R.A.; PARDO-TRUJILLO, A.; BARBOSA-ESPITIA, A.A.

2017-11-01

Typology and internal texture analyses were performed on detrital zircons obtained from the Miocene sandstones of the Ladrilleros-Juanchaco sedimentary sequence (Colombia, Equatorial Pacific). This analysis was complemented with zircon U/Pb dating to identify typology-age associations as indicators of sediment provenance. Our results show that zircons with S and P dominant typologies have internal structures/zoning indicative of igneous, and potentially also metamorphic, origins. Morphometric results suggest limited transport from source areas. Both typology and U/Pb data point to the western Cordillera as the principal source of detrital materials for this sedimentary sequence. A paleogeographic reconstruction shows that, during the Late Miocene, significant portions of the western Cordillera were uplifted and actively eroding, thereby forming a fluvio-topographic barrier that prevented sediments from the central Cordillera reaching the Pacific basins. Exhumed Miocene plutons located along the axis of the western Cordillera may also have played a role as geomorphologically active massifs. This study demonstrates that typologic analysis on detrital zircon grains is a useful tool for establishing provenance and paleogeography in complex litho-tectonic areas where overlapping U/Pb signatures can lead to contradictory results.

Favourable environments for the deposition of uranium in the Subandean Belt and the Amazon Plain of Peru

International Nuclear Information System (INIS)

Canepa, L.; Rosado, F.

1981-01-01

The area described is located between the east flank of the eastern Cordillera on the territorial limits with Ecuador, Colombia, Brazil and Bolivia. It covers the morphological areas called sub-Andean zone and Amazon plain. The physiographic characteristics change from west to east. In the eastern Cordillera the morphology is rough, with altitudes of 5000 m. Descending to sub-Andean, it presents a moderate topography with low hills between 1000 and 2500 m. Further east the Amazon plain forms an extensive peneplain with altitudes of 400 m. The stratigraphy of the area includes rocks with ages from the Precambrian (eastern Cordillera) to recent. Outcrops of the Palaeozoic formations are found to the east of the eastern Cordillera. Rocks that belong to the Mesozoic and Cenozoic are extensively distributed in the area, as deposits of continental or deltaic facies. The geological evolution of the area is favourable for the formation of stratiform deposits of uranium. The intensity of the orogenic deformation decreases progressively from west to east. The tendency to low dips favours the conditions of migration and precipitation of uranium. The majority of the geological formations of continental and deltaic origin, as well as igneous bodies of upper Palaeozoic and Tertiary age, have been selected as rocks of good geological uranium favourability, taking into consideration criteria found in other parts of the world. These have been modified to suit local conditions. This area presents similar geological conditions to the eastern side of the Andean Cordillera in Argentina where a number of uranium deposits have been located. (author)

Provenance of Miocene Hinterland Basins in Ecuador: Implications for the Growth of Topographic Barriers in the Northern Andes

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George, S. W. M.; Horton, B. K.; Vallejo, C.; Nogales, V.

2017-12-01

Establishment of the Eastern Cordillera of Ecuador as an Andean topographic barrier caused significant drainage reorganization, perhaps even as dramatic as the reversal of the Amazon River. Cenozoic growth of this barrier coincided with substantial increases in speciation rates in Andean and Amazonian environments. Situated in the Interandean Depression between the Eastern Cordillera and Western Cordillera of Ecuador, a series of well-preserved Miocene intermontane basins offer a unique opportunity to constrain the along-strike development of the flanking north-trending cordilleras as drainage divides in the Northern Andes. Here were provide detrital zircon U-Pb geochronological results for 17 samples from Ecuadorian hinterland basins (Cuenca, Giron-Santa Isabel, Nabón, Loja, and Vilcabamba), supplemented with measured sections in the Cuenca Basin, to provide insights on orogenic development of the cordilleras of Ecuador during the Miocene. In addition, we characterize the age distributions of basement units to more precisely determine sediment routing patterns through time. Detrital zircon geochronological data yields regional upsection trends throughout Miocene stratigraphic sections marked by: (1) middle Miocene deposits containing a strong syndepositional age peak, with a complementary Eocene-Oligocene peak in varying abundances, and subsidiary low-intensity Paleozoic-Proterozoic age peaks; and (2a) upper Miocene deposits maintaining similar trends to that of the middle Miocene, or (2b) upper Miocene deposits showing a dramatic shutoff of most Cenozoic populations and a switch to Paleozoic-Proterozoic sources, as seen in the Nabón and Loja basins. Syndepositional signatures reflect derivation from the magmatic arc, while varying inputs of Eocene-Oligocene zircons were derived from the Eocene-Oligocene volcanic rocks that comprise the effective basement of much of the Interandean Depression. The late Miocene shift to Paleozoic-Proterozoic sources observed in

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

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Bastida Cuairán, J.

1999-12-01

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

Discovery and description of a new trichostrongyloid species (Nematoda: Ostertagiinae), abomasal parasites in mountain goat, Oreamnos americanus, from the Western Cordillera of North America.

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Hoberg, Eric P; Abrams, Arthur; Pilitt, Patricia A; Jenkins, Emily J

2012-08-01

Marshallagia lichtenfelsi sp. n. is a dimorphic ostertagiine nematode occurring in the abomasum of mountain goats, Oreamnos americanus, from the Western Cordillera of North America. Major and minor morphotype males and females are characterized and distinguished relative to the morphologically similar Marshallagia marshalli / Marshallagia occidentalis from North America and Marshallagia dentispicularis, along with other congeners, from the Palearctic region. The configuration of the convoluted and irregular synlophe in the cervical region of males and females of M. lichtenfelsi is apparently unique, contrasting with a continuous and parallel system of ridges among those species of Marshallagia, including M. marshalli/M. occidentalis, which have been evaluated. Specimens of M. lichtenfelsi are further defined by the rectangular form of the accessory bursal membrane (width > length) in the major morphotype and by the trapezoidal Sjöberg's organ in the minor morphotype, in addition to specific attributes of the spicules and spicule tips. We regard 12 species, including the proposed new taxon, to be valid. Primary diagnostic characters are reviewed for Marshallagia and a framework is presented for standardization of future descriptions incorporating the synlophe in males and females and the structure of the spicules and genital cone in major and minor morphotype males. The center of diversity for species of Marshallagia is the mountain-steppe region of central Eurasia where 11 species (including the Holarctic M. marshalli) are recognized in association with Caprini, Rupicaprini, and Antelopinae; only 2 species occur in the Nearctic. In this assemblage, M. lichtenfelsi is endemic to North America and limited in host distribution to mountain goats. An intricate history for refugial isolation and population fragmentation demonstrated for mountain goats and wild sheep indicates the potential for considerable cryptic diversity for Marshallagia and other nematodes. Shifting

La Cordillera de los Andes: presentación de los problemas geomorfológicos

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1974-01-01

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

Regiones-commodities: Crisis y contagio en Chile

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Antonio Daher

2003-05-01

Full Text Available La hipótesis de un nuevo dualismo entre una capital subglobal y sus "regiones-commodities" subyace en el estudio del impacto diferencial de las tres últimas crisis internacionales en las regiones de Chile, cuantificado a través de cuatro indicadores: el producto, el empleo, la inversión externa y las exportaciones, cuya variación permite verificar la disímil vulnerabilidad de cada región y su desigual exposición al riesgo de contagio de crisis. Fundamentado en un marco conceptual que sostiene que las crisis siguen siendo más regionales que globales, y que existe una verdadera geografía del contagio, el estudio muestra evidencia empírica que permite constatar: 1 la reproducción de un desbalance norte-sur al interior de Chile; 2 la doble paradoja de Santiago, cuya economía es la más diversificada y la más vulnerable, la más recesiva y la de mayor crecimiento; 3 la emergencia de Antofagasta como segunda economía regional de Chile, desplazando a Valparaíso y Concepción; 4 el paralelismo de Santiago y Antofagasta como regiones con el mayor producto, la mayor inversión extranjera y mayores exportaciones; y 5 la "mercosurización" de Santiago, capital subglobal, y la globalización de sus "regiones-commodities".The hypothesis of a new dualism between a sub-global capital city and its "commodities regions" underlies the study of the differential impact of the three last international crises on the regions of Chile. This impact is quantified through four indicators: product, employment, foreign investment and exports, and their variability allow the verification of the dissimilar vulnerability of each region and its dissimilar exposure to the risk of crisis contamination. The study is based on a conceptual frame that states that crisis continue to be more regional-like than global, and that there is a real geography of contamination. On the other hand, this study shows empirical evidence which makes it possible to verify: 1 the

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

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Jiménez-Alfaro, B.

2009-12-01

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

Sensitivity of glaciation in the arid subtropical Andes to changes in temperature, precipitation, and solar radiation

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Vargo, L. J.; Galewsky, J.; Rupper, S.; Ward, D. J.

2018-04-01

The subtropical Andes (18.5-27 °S) have been glaciated in the past, but are presently glacier-free. We use idealized model experiments to quantify glacier sensitivity to changes in climate in order to investigate the climatic drivers of past glaciations. We quantify the equilibrium line altitude (ELA) sensitivity (the change in ELA per change in climate) to temperature, precipitation, and shortwave radiation for three distinct climatic regions in the subtropical Andes. We find that in the western cordillera, where conditions are hyper-arid with the highest solar radiation on Earth, ELA sensitivity is as high as 34 m per % increase in precipitation, and 70 m per % decrease in shortwave radiation. This is compared with the eastern cordillera, where precipitation is the highest of the three regions, and ELA sensitivity is only 10 m per % increase in precipitation, and 25 m per % decrease in shortwave radiation. The high ELA sensitivity to shortwave radiation highlights the influence of radiation on mass balance of high elevation and low-latitude glaciers. We also consider these quantified ELA sensitivities in context of previously dated glacial deposits from the regions. Our results suggest that glaciation of the humid eastern cordillera was driven primarily by lower temperatures, while glaciations of the arid Altiplano and western cordillera were also influenced by increases in precipitation and decreases in shortwave radiation. Using paleoclimate records from the timing of glaciation, we find that glaciation of the hyper-arid western cordillera can be explained by precipitation increases of 90-160% (1.9-2.6× higher than modern), in conjunction with associated decreases in shortwave radiation of 7-12% and in temperature of 3.5 °C.

Measurement of Ra-226 in building materials, with a Na I (Tl) scintillation counter

International Nuclear Information System (INIS)

Vallejo, L.R.; Fuenteseca, J.W.; Rivera, C.A.; Aros, F.H.

1992-01-01

Ra-226 concentration in building materials is determined using gamma-ray spectrometry. Ra-226 contained in sundry materials employed in the construction of dwelling houses and public buildings in Antofagasta city is determined by counting the Pb-214 peaks at 295 KeV and 352 keV, and the Bi-214 peak at 609 keV recorded by means of a 7.5-cm Nal (TI) scintillation counter. (author)

Geomorphological criteria applied to the study of the neotectonic of the internal areas of Spain

International Nuclear Information System (INIS)

Gutierrez Elorza, M.; Pena, J.L.; Rodriguez Vidal, J.; Simon Gomez, J.L.

1984-01-01

Some geomorphological criteria, based on the study of erosion surfaces, glacis, terraces and slopes, after a brief discussion of the geomorphological methodology, are here applied in several internal areas of NE. Spain, specially in the Iberian Cordillera. Several episodes of neotectonic activity are recognised within this Cordillera: a more intense one at the base of Villafranchian times, a second one at the Pliocene/Pleistocene transitional levels, and a latent, more sporadic, intraquaternary activity. (author)

Seismic investigations of the Earth's lithosphere and asthenosphere in two unique convergent margin settings: The Carpathians, Romania, and U.S. Cordillera, Idaho-Oregon

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Stanciu, Adrian Christian

Proposed mechanisms for the unusual seismicity ~100 km southeast of the contact between the Transylvanian Basin and the Eastern Carpathians in Romania have included tearing and rollback of a subducted slab of oceanic lithosphere and gravitational instability and delamination of continental lithosphere. We examined the upper mantle fabrics using shear wave splitting of SK(K)S phases recorded at four broadband seismic stations in the Transylvanian Basin. Our results indicate a regional NW-SE splitting trend, with measurements that reflect an abrupt change from this regional flow field in the vicinity of the Vrancea body to a NE-SW trend that is consistent with redirection of mantle flow. Crustal thickness measurements show 28-30 km in the western part of the Transylvanian Basin, 34-39 km at the contact with the Eastern Carpathians, and 40-45 km further east. These results, along with previous estimates, constrain the locus of the inferred Miocene suture between the southeastern-most portion of the Tisza-Dacia terrane and the East European Platform. The second convergent margin system represented here is in the North American Cordillera in Idaho and Oregon, where subduction and accretion of exotic terranes have modified the western margin of North America. We used teleseismic receiver functions from 85 broadband stations to analyze the geometry of the Salmon River suture zone, the western Idaho shear zone, and the Grouse Creek-Farmington zone boundary. Results show a clear break in crustal thickness from ~28 km beneath the accreted terranes to 36 km east of the surface expression of the WISZ. A strong mid-crustal converter at ~20 km depth is consistent with tectonic wedging during accretion of the Blue Mountains terranes. An eastern Moho offset of ~6 km is consistent with the Archean Grouse Creek-Farmington zone boundary. We used deep converted phases generated beneath the study area to image the mantle transition zone. We observe a continuous high amplitude P410s

Mountain building in the central Andes

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Kono, Masaru; Fukao, Yoshio; Yamamoto, Akihiko

1989-04-01

The Central Andes is the middle part of the Andean chain between about 13°S and 27°S, characterized by the parallel running high mountain chains (the Western and Eastern Cordilleras) at the edges of high plateaus with a height of about 4000 m and a width of 200 to 450 km (the Altiplano-Puna). From the examination of geophysical and geological data in this area, including earthquakes, deformation, gravity anomaly, volcanism, uplift history, and plate motion, we conclude that the continued plate subduction with domination of compressive stress over the entire arc system is the main cause of the tectonic style of the Central Andes. We propose that the present cycle of mountain building has continued in the Cenozoic with the most active phase since the Miocene, and that the present subduction angle (30°) is not typical in that period but that subduction with more shallowly dipping oceanic lithosphere has prevailed at least since the Miocene, because of the young and buoyant slab involved. This situation is responsible for the production of a broad zone of partial melt in the mantle above the descending slab. Addition of volcanic materials was not restricted to the western edge (where active volcanoes of the Western Cordillera exist) but extended to the western and central portion of the Altiplano-Puna. The western half of the Central Andes is essentially isostatic because the heat transferred with the volcanic activities softened the crust there. In the eastern edge, the thermal effect is small, and the crust is strongly pushed by the westward moving South American plate. This caused the shortening of crustal blocks due to reverse faulting and folding in the Eastern Cordillera and Amazonian foreland. The magmatism and crustal accretion are dominant at the western end of the mountain system and decrease eastward, while the compression and consequent crustal shortening are strongest at the eastern end and wane toward west. These two processes are superposed between

Magneto stratigraphy and 40Ar - 39Ar dating of the neogene synorogenic strata of Northern Mendoza, Argentina: Tectonic implications

International Nuclear Information System (INIS)

Irigoyen, Maria V.; Ramos, Victor A.; Brown, Richard L.

1998-01-01

Full text: At the southernmost extension of the Pre cordillera fold-and-thrust belt, 33 S latitude, about 4000 m of Cenozoic foreland-basin strata record the eastern migration of the Andean thrust from since the Neogene. These deposits accumulated in response to exhumation and deformation of the western Principal and Frontal cordilleras. The detrial clastic strata cropping out in the La Pilona-Tupungato region, comprise five formation units that record fluvial, eolian and alluvial deposition in an arid setting. To link the sequence of deformational events in the western mountain belts with the sedimentary record, all units except the youngest have been dated using magnetic polarity stratigraphy calibrated with 40 Ar - 39 Ar dates on inter bedded tephras. A precise chronology of these deposits in conjunction with a multiple data set that include rates of sedimentation in the foreland, a provenance study on these rocks, and facies and textural patterns, provide the basis for documenting details of tectonic activity, volcanism and deposition. The oldest Marinio Fm., whose deposition spans ∼15.7-12.2 Ma, is interpreted to record two phases of thrusting in the Principal Cordillera (Irigoyen 1997). The earlier phase is tied to deformation of the Mesozoic andesitic volcanic complex cropping out in the western part of the Aconcagua fold-and-thrust belt. The second phase of thrusting is linked with deformation of the Mesozoic marine sequences of the central part of the Aconcagua fold-and-thrust belt. The overlying La Pilona Fm., whose deposition spans ∼11.7-9.0 Ma, is thought to record the initiation of exhumation of the Frontal Cordillera. Provenance and paleocurrent data are consistent with clast derivation from northwestern highland sources (i.e., cordon and cuchillas del Tigre) which provided volcanic detritus from the Choiyoi Group and low-grade metamorphic and sedimentary rocks of lower Paleozoic age. Exhumation and displacement of the Frontal Cordillera

Urban weather data and building models for the inclusion of the urban heat island effect in building performance simulation.

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Palme, M; Inostroza, L; Villacreses, G; Lobato, A; Carrasco, C

2017-10-01

This data article presents files supporting calculation for urban heat island (UHI) inclusion in building performance simulation (BPS). Methodology is used in the research article "From urban climate to energy consumption. Enhancing building performance simulation by including the urban heat island effect" (Palme et al., 2017) [1]. In this research, a Geographical Information System (GIS) study is done in order to statistically represent the most important urban scenarios of four South-American cities (Guayaquil, Lima, Antofagasta and Valparaíso). Then, a Principal Component Analysis (PCA) is done to obtain reference Urban Tissues Categories (UTC) to be used in urban weather simulation. The urban weather files are generated by using the Urban Weather Generator (UWG) software (version 4.1 beta). Finally, BPS is run out with the Transient System Simulation (TRNSYS) software (version 17). In this data paper, four sets of data are presented: 1) PCA data (excel) to explain how to group different urban samples in representative UTC; 2) UWG data (text) to reproduce the Urban Weather Generation for the UTC used in the four cities (4 UTC in Lima, Guayaquil, Antofagasta and 5 UTC in Valparaíso); 3) weather data (text) with the resulting rural and urban weather; 4) BPS models (text) data containing the TRNSYS models (four building models).

Imaging Lithospheric-scale Structure Beneath Northern Altiplano in Southern Peru and Northern Bolivia

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Kumar, A.; Wagner, L. S.; Beck, S. L.; Zandt, G.; Long, M. D.

2014-12-01

The northern Altiplano plateau of southern Peru and northern Bolivia is one of the highest topographic features on the Earth, flanked by Western and Eastern Cordillera along its margin. It has strongly influenced the local and far field lithospheric deformation since the early Miocene (Masek et al., 1994). Previous studies have emphasized the importance of both the crust and upper mantle in the evolution of Altiplano plateau (McQuarrie et al., 2005). Early tomographic and receiver function studies, south of 16° S, show significant variations in the crust and upper mantle properties in both perpendicular and along strike direction of the Altiplano plateau (Dorbath et. al., 1993; Myers et al., 1998; Beck and Zandt, 2002). In order to investigate the nature of subsurface lithospheric structure below the northern Altiplano, between 15-18° S, we have determined three-dimensional seismic tomography models for Vp and Vs using P and S-wave travel time data from two recently deployed local seismic networks of CAUGHT and PULSE. We also used data from 8 stations from the PERUSE network (PERU Subduction Experiment). Our preliminary tomographic models show a complex variation in the upper mantle velocity structure with depth, northwest and southeast of lake Titicaca. We see the following trend, at ~85 km depth, northwest of lake Titicaca: low Vp and Vs beneath the Western Cordillera, high Vs beneath the Altiplano and low Vp and Vs beneath the Eastern Cordillera. This low velocity anomaly, beneath Eastern Cordillera, seems to coincide with Kimsachata, a Holocene volcano in southern Peru. At depth greater than ~85 km: we find high velocity anomaly beneath the Western Cordillera and low Vs beneath the Altiplano. This high velocity anomaly, beneath Western Cordillera, coincides with the well-located Wadati-Benioff zone seismicity and perhaps represents the subducting Nazca slab. On the southeast of lake Titicaca, in northern Bolivia, we see a consistently high velocity anomaly

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

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Gustavo Basil

2009-06-01

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

Faulting and erosion in the Argentine Precordillera during changes in subduction regime: Reconciling bedrock cooling and detrital records

Science.gov (United States)

Fosdick, Julie C.; Carrapa, Barbara; Ortíz, Gustavo

2015-12-01

The Argentine Precordillera is an archetypal retroarc fold-and-thrust belt that records tectonics associated with changing subduction regimes. The interactions between exhumation and faulting in the Precordillera were investigated using apatite and zircon (U-Th-Sm)/He and apatite fission track thermochronometry from the Precordillera and adjacent geologic domains. Inverse modeling of thermal histories constrains eastward in-sequence rock cooling associated with deformation and erosion from 18 to 2 Ma across the Central Precordillera tracking thrusting during this time. The youngest AHe ages (5-2 Ma) and highest erosion rates are located in the eastern and western extremities of the Precordillera and indicate that recent denudation is concentrated at its structural boundaries. Moreover, synchronous rapid Pliocene cooling of the Frontal Cordillera, Eastern Precordillera, and Sierra del Valle Fértil was coeval with initiation of basement-involved faulting in the foreland. Detrital zircon U-Pb geochronology from the ca. 16-8.1 Ma Bermejo foreland basin strata suggests fluvial connectivity westward beyond the Frontal Cordillera to the Main Cordillera and Coast Range followed by an important shift in sediment provenance at ca. 10 Ma. At this time, we suggest that a substantial decrease in Permo-Triassic igneous sources in the Frontal Cordillera and concurrent increase in recycled zircons signatures of Paleozoic strata are best explained by uplift and erosion of the Precordillera during widening of the thrust-belt. Bedrock thermochronology and modeling indicate a 2-6 Myr lag time between faulting-related cooling in the hinterland and the detrital record of deformation in the foreland basin, suggesting that for tectonically active semi-arid settings, bedrock cooling may be more sensitive to onset of faulting. We suggest that high erosion rates in the Frontal Cordillera and Eastern Precordillera are associated with increased interplate coupling during shallowing of the

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

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Jiménez-Alfaro, B.

2005-12-01

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

Source apportionment of PM₁₀ and PM₂.₅ in a desert region in northern Chile.

Science.gov (United States)

Jorquera, Héctor; Barraza, Francisco

2013-02-01

Estimating contributions of anthropogenic sources to ambient particulate matter (PM) in desert regions is a challenging issue because wind erosion contributions are ubiquitous, significant and difficult to quantify by using source-oriented, dispersion models. A receptor modeling analysis has been applied to ambient PM(10) and PM(2.5) measured in an industrial zone ~20 km SE of Antofagasta (23.63°S, 70.39°W), a midsize coastal city in northern Chile; the monitoring site is within a desert region that extends from northern Chile to southern Perú. Integrated 24-hour ambient samples of PM(10) and PM(2.5) were taken with Harvard Impactors; samples were analyzed by X Ray Fluorescence, ionic chromatography (NO(3)(-) and SO(4)(=)), atomic absorption (Na(+), K(+)) and thermal optical transmission for elemental and organic carbon determination. Receptor modeling was carried out using Positive Matrix Factorization (US EPA Version 3.0); sources were identified by looking at specific tracers, tracer ratios, local winds and wind trajectories computed from NOAA's HYSPLIT model. For the PM(2.5) fraction, six contributions were found - cement plant, 33.7 ± 1.3%; soil dust, 22.4 ± 1.6%; sulfates, 17.8 ± 1.7%; mineral stockpiles and brine plant, 12.4 ± 1.2%; Antofagasta, 8.5 ± 1.3% and copper smelter, 5.3 ± 0.8%. For the PM(10) fraction five sources were identified - cement plant, 38.2 ± 1.5%; soil dust, 31.2 ± 2.3%; mineral stockpiles and brine plant, 12.7 ± 1.7%; copper smelter, 11.5 ± 1.6% and marine aerosol, 6.5 ± 2.4%. Therefore local sources contribute to ambient PM concentrations more than distant sources (Antofagasta, marine aerosol) do. Soil dust is enriched with deposition of marine aerosol and calcium, sulfates and heavy metals from surrounding industrial activities. The mean contribution of suspended soil dust to PM(10) is 50 μg/m(3) and the peak daily value is 104 μg/m(3). For the PM(2.5) fraction, suspended soil dust contributes with an average of 9.3 �

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

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Mary Jadán V.

2018-03-01

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

Taxonomic novelties within the genus Columnea (Gesneriaceae)

International Nuclear Information System (INIS)

Amaya Marquez, Marisol

2010-01-01

A new species of Columnea and a new variety of Columnea lanata (Seem.) Kuntze belonging to section Collandra (Gesneriaceae) are described and illustrated. The new species was found in the Pacific slopes of the Cordillera Occidental in the Department of Choco in Colombia; the new variety comes from the Pacific slopes of the Cordillera Occidental, in the region of Murri located at the North West of the Department of Antioquia . A taxonomic key to distinguish the new species from the morphologically closer species is presented.

The relationship between carbonate facies, volcanic rocks and plant remains in a late Palaeozoic lacustrine system (San Ignacio Fm, Frontal Cordillera, San Juan province, Argentina)

Science.gov (United States)

Busquets, P.; Méndez-Bedia, I.; Gallastegui, G.; Colombo, F.; Cardó, R.; Limarino, O.; Heredia, N.; Césari, S. N.

2013-07-01

The San Ignacio Fm, a late Palaeozoic foreland basin succession that crops out in the Frontal Cordillera (Argentinean Andes), contains lacustrine microbial carbonates and volcanic rocks. Modification by extensive pedogenic processes contributed to the massive aspect of the calcareous beds. Most of the volcanic deposits in the San Ignacio Fm consist of pyroclastic rocks and resedimented volcaniclastic deposits. Less frequent lava flows produced during effusive eruptions led to the generation of tabular layers of fine-grained, greenish or grey andesites, trachytes and dacites. Pyroclastic flow deposits correspond mainly to welded ignimbrites made up of former glassy pyroclasts devitrified to microcrystalline groundmass, scarce crystals of euhedral plagioclase, quartz and K-feldspar, opaque minerals, aggregates of fine-grained phyllosilicates and fiammes defining a bedding-parallel foliation generated by welding or diagenetic compaction. Widespread silicified and silica-permineralized plant remains and carbonate mud clasts are found, usually embedded within the ignimbrites. The carbonate sequences are underlain and overlain by volcanic rocks. The carbonate sequence bottoms are mostly gradational, while their tops are usually sharp. The lower part of the carbonate sequences is made up of mud which appear progressively, filling interstices in the top of the underlying volcanic rocks. They gradually become more abundant until they form the whole of the rock fabric. Carbonate on volcanic sandstones and pyroclastic deposits occur, with the nucleation of micritic carbonate and associated production of pyrite. Cyanobacteria, which formed the locus of mineral precipitation, were related with this nucleation. The growth of some of the algal mounds was halted by the progressive accumulation of volcanic ash particles, but in most cases the upper boundary is sharp and suddenly truncated by pyroclastic flows or volcanic avalanches. These pyroclastic flows partially destroyed the

Observaciones fitogeográficas en el páramo de la cordillera oriental del Ecuador

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1983-01-01

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

Differential response to ocean acidification in physiological traits of Concholepas concholepas populations

Science.gov (United States)

Lardies, Marco A.; Arias, María Belén; Poupin, María Josefina; Manríquez, Patricio H.; Torres, Rodrigo; Vargas, Cristian A.; Navarro, Jorge M.; Lagos, Nelson A.

2014-07-01

Phenotypic adaptation to environmental fluctuations frequently occurs by preexisting plasticity and its role as a major component of variation in physiological diversity is being widely recognized. Few studies have considered the change in phenotypic flexibility among geographic populations in marine calcifiers to ocean acidification projections, despite the fact that this type of study provides understanding about how the organism may respond to this chemical change in the ocean. We examined the geographic variation in CO2 seawater concentrations in the phenotype and in the reaction norm of physiological traits using a laboratory mesocosm approach with short-term acclimation in two contrasting populations (Antofagasta and Calfuco) of the intertidal snail Concholepas concholepas. Our results show that elevated pCO2 conditions increase standard metabolic rates in both populations of the snail juveniles, likely due to the higher energy cost of homeostasis. Juveniles of C. concholepas in the Calfuco (southern) population showed a lower increment of metabolic rate in high-pCO2 environments concordant with a lesser gene expression of a heat shock protein with respect to the Antofagasta (northern) population. Combined these results indicate a negative effect of ocean acidification on whole-organism functioning of C. concholepas. Finally, the significant Population × pCO2 level interaction in both studied traits indicates that there is variation between populations in response to high-pCO2 conditions.

Communities of nirS-type denitrifiers in the water column of the oxygen minimum zone in the eastern South Pacific.

Science.gov (United States)

Castro-González, Maribeb; Braker, Gesche; Farías, Laura; Ulloa, Osvaldo

2005-09-01

The major sites of water column denitrification in the ocean are oxygen minimum zones (OMZ), such as one in the eastern South Pacific (ESP). To understand the structure of denitrifying communities in the OMZ off Chile, denitrifier communities at two sites in the Chilean OMZ (Antofagasta and Iquique) and at different water depths were explored by terminal restriction fragment length polymorphism analysis and cloning of polymerase chain reaction (PCR)-amplified nirS genes. NirS is a functional marker gene for denitrification encoding cytochrome cd1-containing nitrite reductase, which catalyses the reduction of nitrite to nitric oxide, the key step in denitrification. Major differences were found between communities from the two geographic locations. Shifts in community structure occurred along a biogeochemical gradient at Antofagasta. Canonical correspondence analysis indicated that O2, NO3-, NO2- and depth were important environmental factors governing these communities along the biogeochemical gradient in the water column. Phylogenetic analysis grouped the majority of clones from the ESP in distinct clusters of genes from presumably novel and yet uncultivated denitrifers. These nirS clusters were distantly related to those found in the water column of the Arabian Sea but the phylogenetic distance was even higher compared with environmental sequences from marine sediments or any other habitat. This finding suggests similar environmental conditions trigger the development of denitrifiers with related nirS genotypes despite large geographic distances.

Urban weather data and building models for the inclusion of the urban heat island effect in building performance simulation

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M. Palme

2017-10-01

Full Text Available This data article presents files supporting calculation for urban heat island (UHI inclusion in building performance simulation (BPS. Methodology is used in the research article “From urban climate to energy consumption. Enhancing building performance simulation by including the urban heat island effect” (Palme et al., 2017 [1]. In this research, a Geographical Information System (GIS study is done in order to statistically represent the most important urban scenarios of four South-American cities (Guayaquil, Lima, Antofagasta and Valparaíso. Then, a Principal Component Analysis (PCA is done to obtain reference Urban Tissues Categories (UTC to be used in urban weather simulation. The urban weather files are generated by using the Urban Weather Generator (UWG software (version 4.1 beta. Finally, BPS is run out with the Transient System Simulation (TRNSYS software (version 17. In this data paper, four sets of data are presented: 1 PCA data (excel to explain how to group different urban samples in representative UTC; 2 UWG data (text to reproduce the Urban Weather Generation for the UTC used in the four cities (4 UTC in Lima, Guayaquil, Antofagasta and 5 UTC in Valparaíso; 3 weather data (text with the resulting rural and urban weather; 4 BPS models (text data containing the TRNSYS models (four building models.

Seismicity, fault plane solutions, depth of faulting, and active tectonics of the Andes of Peru, Ecuador, and southern Colombia

Science.gov (United States)

Suarez, G.; Molnar, P.; Burchfiel, B. C.

1983-01-01

The long-period P waveforms observed for 17 earthquakes in the Peruvian Andes during 1963-1976 are compared with synthetic waveforms to obtain fault-plane solutions and focal depths. The morphological units of the Peruvian Andes are characterized: coastal plains, Cordillera Occidental, altiplano and central high plateau, Cordillera Oriental, and sub-Andes. The data base and analysis methodology are discussed, and the results are presented in tables, diagrams, graphs, maps, and photographs illustrating typical formations. Most of the earthquakes are shown to occur in the transition zone from the sub-Andes to the Cordillera Oriental under formations of about 1 km elevation at focal depths of 10-38 km. It is suggested that the sub-Andean earthquakes reflect hinterland deformation of a detached fold and thrust belt, perhaps like that which occurred in parts of the Canadian Rockies. From the total crustal shortening evident in Andean morphology and the shortening rate of the recent earthquakes it is estimated that the topography and crustal root of the Andes have been formed during the last 90-135 Myr.

Seguimiento fotométrico de tránsitos exoplanetarios

Science.gov (United States)

Char, F.; Unda-Sanzana, E.; Kipping, D.; Colazo, C.; Núñez, R.; Guzzo, P.; Schneiter, M.; Colque, J. P.

The Unidad de Astronomía of the Universidad de Antofagasta (Chile) has begun a collaboration with the University College London, the Observatorio Astronómico de Córdoba and the Instituto de Astronomía Teórica y Experimental at Universidad Nacional de Córdoba, to enlarge a rich database of exoplanetary transits, with the efforts from both profesional and amateur astronomers. These data will be used to test Transit Timing Variations (TTVs) and help to improve the existing exoplanet databases. FULL TEXT IN SPANISH

LA CASA GIBBS Y EL MONOPOLIO SALITRERO PERUANO: 1876-1878

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Manuel Ravest Mora

2008-06-01

Full Text Available El objeto de este breve trabajo es mostrar la disposición de Anthony Gibbs & Sons, y de sus filiales, a apoyar el proyecto monopólico salitrero del Perú con recursos monetarios y los manejos de sus directores en la única empresa que, dada su capacidad de elaboración, podía hacerlo fracasar: la Compañía de Salitres y Ferrocarril de Antofagasta, de la que Gibbs era el segundo mayor accionista. Para el gobierno chileno la causa primaria de la guerra de 1879 fue el intento del Perú por monopolizar la producción salitrera. Bolivia, su aliada secreta desde 1873, colaboró arrendándole y vendiéndole sus depósitos de nitrato, e imponiendo a la exportación del salitre un tributo que infringió la condición -estipulada en un Tratado de Límites- bajo la cual Chile le cedió territorio. Su recuperación manu militari inició el conflicto. A partir de la segunda mitad del siglo pasado esta tesis economicista-legalista fue cuestionada en Chile y en el exterior, desplazando el acento causal al reordenamiento de los mercados de materias primas -de las que los beligerantes eran exportadores- a consecuencia de la crisis mundial de la década de 1870.This brief study aims at showing Anthony Gibbs & Sons disposition in supporting the Peruvian monopolistic nitrate project with monetary resources and its Director's influences in the only company which, due its production's capacity, could make the project fail: the Chilean Antofagasta Nitrate and Railway Co. in which Gibbs was the second most important stockholder. According to Chilean government the primary cause of 1879's war was Peru's attempt to monopolize nitrate production. Bolivia, its secret allied since 1873, helped renting and selling him her nitrate fields and imposing a tax on the nitrate exports of the Chilean company in Antofagasta, thus violating the condition stated in a Border Treaty by which Chile had ceded territory. Its recovery through the use of military forcé was the first act

Vulnerabilidad y periferia interior

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Paula Kápstein López

2010-07-01

This research is about the fragmentation of city centres in Chile. These areas are formed by internal limits that generate problems in relation to the process of urban growth without planning. Therefore, we tried to understand the process of obsolescence that generated segregated areas both physically and socially from the rest of the city. With this goal we defined a concept: the Inner Periphery. This is an original idea that refers to those degraded spaces situated in the urban centre of the city. These inner peripheries derive from the old peripheries that have been in place for decades. One of the objectives of this work is to determine how important was the absence of urban planning in the origin of these vulnerabilities. To do this we defined two methodologies. The first is the locating inner peripheries method and the other is the evaluation of these areas. Both methodologies are complementary and were applied to the study of two Chilean cities, Arica and Antofagasta, in order to generate recommendations for the improvement of the areas of urban decay. In this paper we will analyze one of these cities: Antofagasta. It is a good example of the signs that can be generated in urban territories by industrial activities. On the other hand, the localization and delimitation of the inner peripheries allowed us to assess the importance of the growth process in the origin of the urban decay.

Crustal structure of north Peru from analysis of teleseismic receiver functions

Science.gov (United States)

Condori, Cristobal; França, George S.; Tavera, Hernando J.; Albuquerque, Diogo F.; Bishop, Brandon T.; Beck, Susan L.

2017-07-01

In this study, we present results from teleseismic receiver functions, in order to investigate the crustal thickness and Vp/Vs ratio beneath northern Peru. A total number of 981 receiver functions were analyzed, from data recorded by 28 broadband seismic stations from the Peruvian permanent seismic network, the regional temporary SisNort network and one CTBTO station. The Moho depth and average crustal Vp/Vs ratio were determined at each station using the H-k stacking technique to identify the arrival times of primary P to S conversion and crustal reverberations (PpPms, PpSs + PsPms). The results show that the Moho depth correlates well with the surface topography and varies significantly from west to east, showing a shallow depth of around 25 km near the coast, a maximum depth of 55-60 km beneath the Andean Cordillera, and a depth of 35-40 km further to the east in the Amazonian Basin. The bulk crustal Vp/Vs ratio ranges between 1.60 and 1.88 with the mean of 1.75. Higher values between 1.75 and 1.88 are found beneath the Eastern and Western Cordilleras, consistent with a mafic composition in the lower crust. In contrast values vary from 1.60 to 1.75 in the extreme flanks of the Eastern and Western Cordillera indicating a felsic composition. We find a positive relationship between crustal thickness, Vp/Vs ratio, the Bouguer anomaly, and topography. These results are consistent with previous studies in other parts of Peru (central and southern regions) and provide the first crustal thickness estimates for the high cordillera in northern Peru.

Subdivision of Glacial Deposits in Southeastern Peru Based on Pedogenic Development and Radiometric Ages

Science.gov (United States)

Goodman, Adam Y.; Rodbell, Donald T.; Seltzer, Geoffrey O.; Mark, Bryan G.

2001-07-01

The Cordillera Vilcanota and Quelccaya Ice Cap region of southern Peru (13°30‧-14°00‧S; 70°40‧-71°25‧W) contains a detailed record of late Quaternary glaciation in the tropical Andes. Quantification of soil development on 19 moraine crests and radiocarbon ages are used to reconstruct the glacial history. Secondary iron and clay increase linearly in Quelccaya soils and clay accumulates at a linear rate in Vilcanota soils, which may reflect the semicontinuous addition of eolian dust enriched in secondary iron to all soils. In contrast, logarithmic rates of iron buildup in soils in the Cordillera Vilcanota reflect chemical weathering; high concentrations of secondary iron in Vilcanota tills may mask the role of eolian input to these soils. Soil-age estimates from extrapolation of field and laboratory data suggest that the most extensive late Quaternary glaciation occurred >70,000 yr B.P. This provides one of the first semiquantitative age estimates for maximum ice extent in southern Peru and is supported by a minimum-limiting age of ∼41,520 14C yr B.P. A late glacial readvance culminated ∼16,650 cal yr B.P. in the Cordillera Vilcanota. Following rapid deglaciation of unknown extent, an advance of the Quelccaya Ice Cap occurred between ∼13,090 and 12,800 cal yr B.P., which coincides approximately with the onset of the Younger Dryas cooling in the North Atlantic region. Moraines deposited <394 cal yr B.P. in the Cordillera Vilcanota and <300 cal yr B.P. on the west side of the Quelccaya Ice Cap correlate with Little Ice Age moraines of other regions.

Lithological and Hydrothermal Alteration Mapping of Epithermal, Porphyry and Tourmaline Breccia Districts in the Argentine Andes Using ASTER Imagery

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Francisco J. Testa

2018-01-01

Full Text Available The area of interest is located on the eastern flank of the Andean Cordillera, San Juan province, Argentina. The 3600 km2 area is characterized by Siluro-Devonian to Neogene sedimentary and igneous rocks and unconsolidated Quaternary sediments. Epithermal, porphyry-related, and magmatic-hydrothermal breccia-hosted ore deposits, common in this part of the Frontal Cordillera, are associated with various types of hydrothermal alteration assemblages. Kaolinite – alunite-rich argillic, quartz – illite-rich phyllic, epidote – chlorite – calcite-rich propylitic and silicic are the most common hydrothermal alteration assemblages in the study area. VNIR, SWIR and TIR ASTER data were used to characterize geological features on a portion of the Frontal Cordillera. Red-green-blue band combinations, band ratios, logical operations, mineral indices and principal component analysis were applied to successfully identify rock types and hydrothermal alteration zones in the study area. These techniques were used to enhance geological features to contrast different lithologies and zones with high concentrations of argillic, phyllic, propylitic alteration mineral assemblages and silicic altered rocks. Alteration minerals detected with portable short-wave infrared spectrometry in hand specimens confirmed the capability of ASTER to identify hydrothermal alteration assemblages. The results from field control areas confirmed the presence of those minerals in the areas classified by ASTER processing techniques and allowed mapping the same mineralogy where pixels had similar information. The current study proved ASTER processing techniques to be valuable mapping tools for geological reconnaissance of a large area of the Argentinean Frontal Cordillera, providing preliminary lithologic and hydrothermal alteration maps that are accurate as well as cost and time effective.

IDEALES REGULATORIOS SOBRE EMBARAZO Y MATERNIDAD EN HOMBRES Y MUJERES JÓVENES DEL NORTE DE CHILE

OpenAIRE

Segovia,Jimena Silva; Caro,Leyla Méndez

2015-01-01

Resumen Este artículo se propone comprender los ideales regulatorios sobre embarazo y maternidad/paternidad en hombres y mujeres jóvenes, de enseñanza media de establecimientos privados y municipalizados de las ciudades de Antofagasta y Calama, Chile. Asimismo, se interpretan las construcciones subjetivas y sociales de acuerdo a dimensiones de género y nivel socioeconómico. La producción de información se llevó a cabo a través de entrevistas semiestructuradas y grupos de conversación. Los pri...

VIOLENCIA PSICOLÓGICA EN EL NOVIAZGO EN ESTUDIANTES UNIVERSITARIOS CHILENOS: DIFERENCIAS EN EL APEGO Y LA EMPATÍA DIÁDICA

OpenAIRE

Mónica Guzmán-González; Stephanie García; Bárbara Sandoval; Nicol Vásquez; Camila Villagrán

2014-01-01

El propósito del estudio fue evaluar diferencias en el apego romántico y la empatía diádica en función de la presencia/ausencia de violencia psicológica perpetrada en relaciones de noviazgo entre jóvenes universitarios. La muestra constó de 470 estudiantes entre los 18 y 28 años de la ciudad de Antofagasta, Chile, quienes completaron el cuestionario de Experiencias en Relaciones Cercanas (Brennan, Clark & Shaver, 1998), el Índice de Reactividad Interpersonal para Parejas (Péloquin & Lafontain...

Recursos vegetales: uso, consumo y producción en la Puna meridional argentina (5000-1500 AP)

OpenAIRE

Aguirre, María Gabriela

2012-01-01

Esta investigación es una contribución al conocimiento sobre los recursos vegetales empleados en el pasado en la microrregión de Antofagasta de la Sierra (Catamarca, Argentina). Se aborda la gestión de los recursos vegetales en un lapso que se extiende entre aproximadamente los 5.000 a 1.500 años antes del presente. Se optó por un enfoque que permitiera contemplar las diferentes formas de relación entre los grupos humanos y las plantas y además que proporcionara una representación d...

Nueva especie de zapote de monte (Phragmotheca, Bombacacea en bosques premontanos del centro de Colombia

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Fernández Alonso José Luis

1999-11-01

Full Text Available A new species of Phragmotheca (Bombacaceae is described and illustrated. This represents the first record of this genus in premontane forest (subandean belt and is also the first locality for Phragmotheca in the Eastern Cordillera of Colombia. The genus was previously known only from the Chocó biogeographic region and the Amazonian lowlands.Se describe e ilustra una nueva especie de Phragmotheca (Bombacaceae, que representa el primer registro del género en bosques premontanos (franja subandina y en la Cordillera Oriental de Colombia. Phragmotheca era conocido hasta ahora, sólo de la región biogeográfica chocoana y de la planicie amazónica.

The Balearic Islands in the Alpine Orogeny

Energy Technology Data Exchange (ETDEWEB)

Bourrouilh, R.

2016-10-01

The place of the Balearic Islands in the Alpine orogeny is examined using detailed sedimentology studies, stratigraphical studies from the Lower Devonian (Lochkovian) to modern times and a careful tectonic review of sedimentary formations from the Western Mediterranean. Despite being considered as the ultimate end of the north-eastern termination of the Betic Cordillera, the history of the Balearic archipelago seems to be closer to the tectonic opening of the Gulf of Valencia and to the Corsica-Sardinia rotation, and thus to the tectonic history of the Western Mediterranean Sea, than to the tectonics of the Betic Cordillera which appear as its symmetrical image with respect to this opening. (Author)

Gestión, protección y despoblación en las Reservas de la Biosfera de la Cordillera Cantábrica

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Santos González, J.

2016-12-01

Full Text Available Our study analyses the current status of the Biosphere Reserves on the Cantabrian Mountains, especially the relationships that they have with other Protected Natural Areas with which very often coincide. These relationships concerns management bodies and one of their main problems that has to do with their negative demographic dynamic that has led to an intense depopulation and aging of their local population. Although twelve reserves have been declared, there are still many areas which have not been named reserves but they potentially could. This tells us that we are still far from a Biosphere Reserve of the Great Cantabrian Mountain Range. The management is different depending on the regions: in Asturias, it is the regional administrative department which performs its management; in Galicia, the provincial administrative department and in Castilla and León, it’s the local government who is in charge of its management. Depopulation is one of the most serious problems suffered almost by every Cantabrian reserves and as a process has not stopped yet. The status of the Biosphere Reserve has yet to find its place in the context of other figures that are clearly under protection. In general, the aim of our study is to underline the importance of separating this figure from other more consolidated concerning Protected Natural Areas, and also, to raise awareness about the serious process of aging and depopulation expressed in their territories.Se analiza la situación actual de las Reservas de la Biosfera de la Cordillera Cantábrica, en especial las relaciones que tienen con los Espacios Naturales Protegidos, con los que a menudo coinciden, las relativas a sus órganos de gestión y a uno de sus principales problemas actuales: su dinámica demográfica negativa que ha desembocado en una intensa despoblación y envejecimiento. Aunque se han declarado doce reservas, aún hay muchas zonas que potencialmente lo podían ser, por lo que aún se est

Depositional Record of the Bagua Basin, Northern Peru: Implications for Climate and Tectonic Evolution of Tropical South America

Science.gov (United States)

Moreno, F.; George, S. W. M.; Williams, L. A.; Horton, B. K.; Garzione, C. N.

2015-12-01

The Andes Mountains exert critical controls on the climate, hydrology, and biodiversity of South America. The Bagua Basin, a low elevation (400-600 m) intermontane basin in northern Peru, offers a unique opportunity to study the ecological, climatic, and structural evolution of the western topographic boundary of the Amazonian foreland. Situated between the Marañon fold-thrust belt of the Western Cordillera and basement block uplifts of the Eastern Cordillera, the Bagua region contains a protracted, semi-continuous record of Triassic through Pleistocene sedimentation. Whereas Triassic-Cretaceous marine deposits were potentially related to extension and regional thermal subsidence, a Paleocene-Eocene shift to shallow marine and fluvial systems marks the onset of foreland basin conditions. Oligocene-Miocene sedimentation corresponds to a braided-meandering fluvial system with exceptional development of paleosols. In this study, we use new detrital zircon U-Pb geochronologic and oxygen stable isotopic datasets to establish a chronology of pre-Andean and Andean processes within the Bagua Basin. Detrital zircon geochronology provides constraints on when the Western and Eastern cordilleras shed sediments into the basin. Syndepositional zircons within Eocene, Oligocene and Miocene strata provide key age control for a previously poorly constrained depositional chronology. Preliminary results suggest a dramatic provenance shift in which Paleocene deposits contain almost exclusively cratonic populations (500-1600 Ma) whereas Eocene deposits show a mix of syndepositional zircons from the magmatic arc, recycled Mesozoic zircons, and cratonic zircon populations. Oxygen stable isotopes (δ18O) of carbonate nodules from Neogene paleosols will help elucidate when the Eastern Cordillera became an orographic barrier intercepting moisture from the Amazon basin to the east. Together, these records will help uncover the history of tectonics and climate interaction in tropical South

Ring faults and ring dikes around the Orientale basin on the Moon.

Science.gov (United States)

Andrews-Hanna, Jeffrey C; Head, James W; Johnson, Brandon; Keane, James T; Kiefer, Walter S; McGovern, Patrick J; Neumann, Gregory A; Wieczorek, Mark A; Zuber, Maria T

2018-08-01

The Orientale basin is the youngest and best-preserved multiring impact basin on the Moon, having experienced only modest modification by subsequent impacts and volcanism. Orientale is often treated as the type example of a multiring basin, with three prominent rings outside of the inner depression: the Inner Rook Montes, the Outer Rook Montes, and the Cordillera. Here we use gravity data from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission to reveal the subsurface structure of Orientale and its ring system. Gradients of the gravity data reveal a continuous ring dike intruded into the Outer Rook along the plane of the fault associated with the ring scarp. The volume of this ring dike is ~18 times greater than the volume of all extrusive mare deposits associated with the basin. The gravity gradient signature of the Cordillera ring indicates an offset along the fault across a shallow density interface, interpreted to be the base of the low-density ejecta blanket. Both gravity gradients and crustal thickness models indicate that the edge of the central cavity is shifted inward relative to the equivalent Inner Rook ring at the surface. Models of the deep basin structure show inflections along the crust-mantle interface at both the Outer Rook and Cordillera rings, indicating that the basin ring faults extend from the surface to at least the base of the crust. Fault dips range from 13-22° for the Cordillera fault in the northeastern quadrant, to 90° for the Outer Rook in the northwestern quadrant. The fault dips for both outer rings are lowest in the northeast, possibly due to the effects of either the direction of projectile motion or regional gradients in pre-impact crustal thickness. Similar ring dikes and ring faults are observed around the majority of lunar basins.

Characterization of the structure of the Salar de Atacama Basin through gravimetric profiles and interval velocity analysis.

Science.gov (United States)

Becerra, J.; Bascunan, S. A.; Maksymowicz, A.; Martínez, F.; Arriagada, C.

2017-12-01

The structure of the basins found in the Preandean Depression in the northern Central Andes has remained elusive, partly due to a poor understanding of the structural styles and stratigraphy beneath their surface. An independent approach to the multiple interpretations of seismic lines available is the analysis of 2D gravity profiles. An E-W profile was performed across the basin, closely matching the surficial trace of previous seismic lines. The profile shows three gravimetric lows, the most relevant being one beneath the Llano de la Paciencia- Cordillera de la Sal, comprised of deformed evaporitic and terrigenous deposits of Oligocene-Early Miocene age. The structure which bounds this gravity low has a steeper dip on its eastern side, bounding the eastern side of the Cordillera de la Sal, which is at odds with previous studies that interpreted its western contact with Cretaceous outcrops as the possible basin boundary. The 3-D analyses of seismic interval velocity data around the gravimetric survey reveal a major vertical contrast in the eastern portion of the profile, interpreted as the bottom of the evaporite successions, followed to the west by a complex, narrow and deep zone of low velocities. Westward, the Cretaceous rocks record higher velocities than its post-Paleocene counterparts, and an almost uniform increase in velocity with depth. The major gravity anomaly is closely related to the Cordillera de la Sal, which consists of an array of folds and reverse faults involving Oligocene to recent deposits. We propose that the faults which generated Oligocene extension are not at the western border of the basin, but around the Cordillera de la Sal, which is the result of Miocene inversion of the same system. Strike-slip deformation was also probably a major contributor in basin formation, as shown by the narrow yet deep shape of the depocenter.

A new species of Microkayla (Anura: Craugastoridae: Holoadeninae) from Department La Paz, Bolivia.

Science.gov (United States)

DE LA Riva, Ignacio; Cortez, Claudia; Burrowes, Patricia A

2017-12-12

We describe a new species of direct-developing frog of the genus Microkayla from the Cordillera Real of the Bolivian Andes, in the Department of La Paz. The new species, Microkayla huayna sp. nov., is closely related to M. teqta and can be distinguished from other species of the genus by its brown dorsal skin and the presence of a large dark brown vocal sac in males. This is the second species of Microkayla known from the Zongo Valley, and the ninth in the Cordillera Real, contributing to a total of 22 described species in Bolivia. Given its small distribution range, we recommend to considering it as Vulnerable according to IUCN criteria.

Characterization by PCR of Vibrio parahaemolyticus isolates collected during the 1997-1998 Chilean outbreak

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JOSÉ LUIS CÓRDOVA

2002-01-01

Full Text Available Between November 1997 and April 1998, several human gastroenteritis cases were reported in Antofagasta, a city in the north of Chile. This outbreak was associated with the consumption of shellfish, and the etiologic agent responsible was identified as Vibrio parahaemolyticus. This was the first report of this bacterium causing an epidemic in Chile. V. parahaemolyticus was the only pathogenic bacterium isolated from patient stools and from shellfish samples. These isolates were analyzed by polymerase chain reaction (PCR amplification of the pR72H gene, a species-specific sequence. Based on the pR72H gene amplification pattern, at least three different isolates of V. parahaemolyticus were found. Two isolates (named amplicons A and C generated PCR products of approximately 400 bp and 340 bp respectively, while another type of isolate designated B, did not generate a PCR product, regardless of which method of DNA purification was used. Sequence analysis of the amplicons A and C shows that they have an 80 bp and 183 bp conserved region at the 5'end of the gene. However, both isolates have different sequences at their 3' terminus and are also different from the pR72H sequence originally reported. Using this PCR assay we demonstrated that these three isolates were found in clinical samples as well as in shellfish. The warm seawater caused by the climatological phenomena "El Niño" perhaps favored the geographic dispersion of the bacterium (bacterial bloom occurring in Antofagasta that occurred during that time of year

Characterization by PCR of Vibrio parahaemolyticus isolates collected during the 1997-1998 Chilean outbreak.

Science.gov (United States)

Córdova, José Luis; Astorga, Josefa; Silva, Wally; Riquelme, Carlos

2002-01-01

Between November 1997 and April 1998, several human gastroenteritis cases were reported in Antofagasta, a city in the north of Chile. This outbreak was associated with the consumption of shellfish, and the etiologic agent responsible was identified as Vibrio parahaemolyticus. This was the first report of this bacterium causing an epidemic in Chile. V. parahaemolyticus was the only pathogenic bacterium isolated from patient stools and from shellfish samples. These isolates were analyzed by polymerase chain reaction (PCR) amplification of the pR72H gene, a species-specific sequence. Based on the pR72H gene amplification pattern, at least three different isolates of V. parahaemolyticus were found. Two isolates (named amplicons A and C) generated PCR products of approximately 400 bp and 340 bp respectively, while another type of isolate designated B, did not generate a PCR product, regardless of which method of DNA purification was used. Sequence analysis of the amplicons A and C shows that they have an 80 bp and 183 bp conserved region at the 5' end of the gene. However, both isolates have different sequences at their 3' terminus and are also different from the pR72H sequence originally reported. Using this PCR assay we demonstrated that these three isolates were found in clinical samples as well as in shellfish. The warm seawater caused by the climatological phenomena "El Niño" perhaps favored the geographic dispersion of the bacterium (bacterial bloom) occurring in Antofagasta that occurred during that time of year.

PIGMENTOS Y PINTURAS DE MINERAL DE COBRE EN LA REGIÓN DE TARAPACÁ, NORTE DE CHILE: NUEVOS DATOS PARA UNA TECNOLOGÍA PIGMENTARIA PREHISPÁNICA

OpenAIRE

Sepúlveda,Marcela; Figueroa,Valentina; Cárcamo,José

2014-01-01

La explotación de los recursos minerales de cobre en el norte de Chile implicó la producción de pigmentos azules y verdes identificados, hasta ahora, en pintura rupestre, en nódulos y en estado de polvo al interior de contenedores de cuero provenientes de distintos cementerios de la cuenca del río Loa, región de Antofagasta, desierto de Atacama. En este artículo, se presentan los primeros resultados de análisis físico-químicos de pintura verde aplicada sobre distintos soportes de cuero: másca...

Monitoreo del glaciar Artesonraju, cordillera blanca

OpenAIRE

Instituto Nacional de Recursos Naturales. Intendencia de Recursos Hídricos. Unidad de Glaciología y Recursos Hídricos; Gómez López, Jesús; Gonzáles Lizarme, Gilber; Cochachín Rapre, Alejo; Quijano, Joe; Tournoud, Matthieu

2003-01-01

Muestra la evolución del glaciar Artesonraju, como sensor del cambio climático y fuente de recurso hídrico, asimismo calcula el balance glaciológico en base a datos hidrometereológicos. Este glaciar esta ubicado en el distrito de Caraz, provincia de Huaylas, departamento de Ancash.

Bolivia Altiplano and Cordillera Occidental Data

Data.gov (United States)

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

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

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Jorge Ignacio del Valle

2011-09-01

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

Slope movements in Callejón de Huyalas, Peru

Czech Academy of Sciences Publication Activity Database

Vilímek, V.; Zapata, M. L.; Stemberk, Josef

2003-01-01

Roč. 35, supplementum (2003), s. 39-51 ISSN 0300-5402 Institutional research plan: CEZ:AV0Z3046908 Keywords : slope movements * natural hazards * Cordillera Blanca Subject RIV: DB - Geology ; Mineralogy

Maxillaria jostii Dodson (Orchidaceae un nuevo registro para la Flora del Perú

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Eric F. Rodríguez Rodríguez

2013-12-01

Full Text Available Se presenta a Maxillaria jostii Dodson (Orchidaceae como una nueva adición a la Flora del Perú procedente de los substratos de roca arenisca de la Cordillera subandina de Huarango (provincia San Ignacio, departamento Cajamarca, una prolongación sureña de la Cordillera del Cóndor rica en especies. Maxillaria jostii ha sido considerada como una especie endémica para Ecuador (Zamora-Chinchipe, Morona-Santiago; sin embargo, con el presente estudio se amplía su distribución geográfica hacia el Perú. Esta nueva contribución al conocimiento de la flora del país es el resultado del trabajo de campo y de herbario, gracias al Proyecto Binacional «Inventario Botánico de la Región de la Cordillera del Cóndor, Ecuador y Perú, 2005-2007», desarrollado entre las instituciones: MO, HUT, LOJA y QCNE. La contrastación específica se realizó con las especies documentadas en el «Catálogo de las Angiospermas y Gimnospermas del Perú» (Brako & Zarucchi 1993, «Diez años de adiciones a la flora del Perú: 1993-2003» (Ulloa Ulloa et al. 2004 y «Nuevas Adiciones de Angiospermas a la Flora del Perú» (Rodríguez et al. 2006b.

Mineralogic and Petrofabric Clues to Evolution of the Early Tertiary Amaga Basin, Colombian Andes

Science.gov (United States)

Sierra, G. M.; MacDonald, W. D.

2002-05-01

The Amaga Basin is a coal-bearing early to mid Tertiary Basin located in the Cauca Valley between the Cordillera Oriental and Cordillera Central of Colombia. The main sedimentary filling, the Late Oligocene to Late Miocene Amaga Formation, has been divided into two Members (Lower and Upper). This division was made possible 1) by identifying stratigraphic base level fluctuations through petrographic characteristics of the associated sandstones and 2) by the distinctive regional variations in magnetic anisotropic susceptibility (AMS). The latter is particularly effective in indicating areas in which tectonic effects overprint sedimentary fabric. Three tectonic stages have affected the Amaga Coal basin: 1. An extensional event during dry seasons that accompanied strike-slip movements along the Cauca-Pat¡a and Romeral faults systems, associated with the eastward approach of the Nazca plate toward the South America plate at 25 m.a.; this extension event was accompanied by highly aggraded braided river deposits whose stacking patterns show a low accumulation/supply (A/S) ratio 2. A rapid subsidence event (prior to 10 m.a.) accompanied by a strong climatic influence (humid, with rainy seasons), representing extensional movements across the Cauca depression and related to the initial eastward migration of a magmatic arc from the Western Cordillera; this allowed the formation of swamps representing epochs of high A/S ratio. 3. A thrusting and folding episode along the Cauca depression coeval with an incipient phase of Combia Formation volcanism (10-7m.a.), during periods of both dry and wet seasons, related to the eastward migration of the magmatic arc into the Central Cordillera; this permitted the development of highly aggraded braided rivers whose stacking patterns represent the lowest A/S ratio of the Amaga Formation. Mineralogic variations and ratios reflect source area contributions and are useful in diagnosing relative uplift and subsidence of the continental shield

Lung function in adults following in utero and childhood exposure to arsenic in drinking water: preliminary findings.

Science.gov (United States)

Dauphiné, David C; Ferreccio, Catterina; Guntur, Sandeep; Yuan, Yan; Hammond, S Katharine; Balmes, John; Smith, Allan H; Steinmaus, Craig

2011-08-01

Evidence suggests that arsenic in drinking water causes non-malignant lung disease, but nearly all data concern exposed adults. The desert city of Antofagasta (population 257,976) in northern Chile had high concentrations of arsenic in drinking water (>800 μg/l) from 1958 until 1970, when a new treatment plant was installed. This scenario, with its large population, distinct period of high exposure, and accurate data on past exposure, is virtually unprecedented in environmental epidemiology. We conducted a pilot study on early-life arsenic exposure and long-term lung function. We present these preliminary findings because of the magnitude of the effects observed. We recruited a convenience sample consisting primarily of nursing school employees in Antofagasta and Arica, a city with low drinking water arsenic. Lung function and respiratory symptoms in 32 adults exposed to >800 μg/l arsenic before age 10 were compared to 65 adults without high early-life exposure. Early-life arsenic exposure was associated with 11.5% lower forced expiratory volume in 1 s (FEV(1)) (P = 0.04), 12.2% lower forced vital capacity (FVC) (P = 0.04), and increased breathlessness (prevalence odds ratio = 5.94, 95% confidence interval 1.36-26.0). Exposure-response relationships between early-life arsenic concentration and adult FEV(1) and FVC were also identified (P trend = 0.03). Early-life exposure to arsenic in drinking water may have irreversible respiratory effects of a magnitude similar to smoking throughout adulthood. Given the small study size and non-random recruitment methods, further research is needed to confirm these findings.

Guiones sexuales de la seducción, el erotismo y los encuentros sexuales en el norte de Chile Sexual scripts about seduction, eroticism and sexual encounters in the north of Chile

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Jimena Silva Segovia

2008-08-01

Full Text Available Este artículo analiza las diversas expresiones que adquieren los encuentros sexuales, la seducción y el erotismo en el norte de Chile. El estudio se realizó usando la Teoría de los scripts sexuales. Se entrevistó a 46 hombres y mujeres de 18 a 69 años de edad de las ciudades de Antofagasta y Calama. Las conclusiones revelan que la construcción de los guiones sexuales se refuerza con los modelos socioculturales inequitativos y jerarquizados existentes en las relaciones de género predominantes en la sociedad chilena, sobretodo en una zona del país donde predomina la minería como principal actividad económica. Además, en los sectores socioeconómicos más bajos se observan, elementos asociados a los modelos más tradicionales, mientras que guiones sexuales con elementos más flexibles y equitativos en los niveles más altos.This article observes the diverse expressions of sexual encounters, seduction and eroticism in the North of Chile. The study was realized using the Sexual Scripts theory. We interviewed 46 men and women from 18 through 69 years of age from the cities of Antofagasta and Calama. The main conclusions reveal that the construction of the sexual scripts is reinforced by the sociocultural inequitable models and predominant gender relationships in the Chilean society, especially in that area, where mining is the most important economic activity. Moreover, in the lower socioeconomic levels we can find elements associated with the most traditional models, whereas sexual scripts with more flexible and equitable elements are found in higher socioeconomic strata.

Aeromagnetic and Bouger Gravity Data from Bolivia

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — As part of a two-year assessment of the geology and mineral resources of the Altiplano and Cordillera Occidental, Bolivia, aeromagnetic and gravity data were...

Tectonics, hydrothermal zoning, and uranium in the central Andes

Energy Technology Data Exchange (ETDEWEB)

Gabelman, J W

1961-01-01

The geological features of the Peruvian Andes are discussed in some detail. The geologic history of the Andrean tectonics was found to be virtually the same as that represented in both North and South American Cordillera. The study indicated that Andrean hydrothermal mineralization occurred intermittently but in close time relation with accompanying deformations from the late Cretaceous or early Tertiary up to the present. The mineralization cycle is discussed as it relates to several metals, particularly uranium. Uranium is believed to occupy the same several temperature--environmental positions in the Andes that it does throughout the rest of the western hemisphere Cordillera. Even though uranium is present in minor quantities in several high-to-moderate-temperature environments, the bulk of uranium present in the cycle is believed to precipitate in the subepithermal environment.

Estudios de competitividad en sistemas urbano - territoriales

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Esteban Soms García

2007-05-01

El Ministerio de Planificación y Cooperación de Chile, ha desarrollado varios estudios relacionados con la competitividad regional, destinados a pronosticar y evaluar los impactos positivos y negativos que podrían derivarse de los recientes Acuerdos de Libre Comercio suscritos por Chile con la Comunidad Europea, Estados Unidos y Corea, más los acuerdos ad portas con los Países de la APEC. En lo referente a competitividad urbana, destacan algunos estudios y proyectos relacionados con el programa gubernamental "Ciudades para el Bicentenario", impulsado el Ministerio de Vivienda y Urbanismo y los Gobiernos Regionales de Antofagasta, Bio Bio, Valparaíso y Santiago.

COLUMNEA RANGELII (GESNERIACEAE, A NEW SPECIES FROM THE SERRANÍA DE LOS PARAGUAS IN THE COLOMBIAN ANDES

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Amaya Marisol

2012-06-01

Full Text Available A new species of Columnea belonging to the section Collandra (Gesneriaceae from La Serranía de los Paraguas in the Department of Valle del Cauca (Cordillera Occidental, Colombia, is described and illustrated.

Source apportionment of PM10 and PM2.5 in a desert region in northern Chile

International Nuclear Information System (INIS)

Jorquera, Héctor; Barraza, Francisco

2013-01-01

Estimating contributions of anthropogenic sources to ambient particulate matter (PM) in desert regions is a challenging issue because wind erosion contributions are ubiquitous, significant and difficult to quantify by using source-oriented, dispersion models. A receptor modeling analysis has been applied to ambient PM 10 and PM 2.5 measured in an industrial zone ∼ 20 km SE of Antofagasta (23.63°S, 70.39°W), a midsize coastal city in northern Chile; the monitoring site is within a desert region that extends from northern Chile to southern Perú. Integrated 24-hour ambient samples of PM 10 and PM 2.5 were taken with Harvard Impactors; samples were analyzed by X Ray Fluorescence, ionic chromatography (NO 3 − and SO 4 = ), atomic absorption (Na + , K + ) and thermal optical transmission for elemental and organic carbon determination. Receptor modeling was carried out using Positive Matrix Factorization (US EPA Version 3.0); sources were identified by looking at specific tracers, tracer ratios, local winds and wind trajectories computed from NOAA's HYSPLIT model. For the PM 2.5 fraction, six contributions were found — cement plant, 33.7 ± 1.3%; soil dust, 22.4 ± 1.6%; sulfates, 17.8 ± 1.7%; mineral stockpiles and brine plant, 12.4 ± 1.2%; Antofagasta, 8.5 ± 1.3% and copper smelter, 5.3 ± 0.8%. For the PM 10 fraction five sources were identified — cement plant, 38.2 ± 1.5%; soil dust, 31.2 ± 2.3%; mineral stockpiles and brine plant, 12.7 ± 1.7%; copper smelter, 11.5 ± 1.6% and marine aerosol, 6.5 ± 2.4%. Therefore local sources contribute to ambient PM concentrations more than distant sources (Antofagasta, marine aerosol) do. Soil dust is enriched with deposition of marine aerosol and calcium, sulfates and heavy metals from surrounding industrial activities. The mean contribution of suspended soil dust to PM 10 is 50 μg/m 3 and the peak daily value is 104 μg/m 3 . For the PM 2.5 fraction, suspended soil dust contributes with an average of 9.3 �

Estudio de la anurofauna del municipio de Ibagué

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M. H. Bernal

2000-07-01

Full Text Available Colombia es considerada, en el mundo, el país más rico en especies de anfibios (Lynch, 1998. De las 4.300 especies registradas en el planeta, Colombia presenta 583 (Ruiz et al., 1996. Esto refleja la gran riqueza que el país tiene respecto a la diversidad  no sólo de anfibios, sino también de otros grupos de animales y plantas. Entre los anfibios el mayor número de especies se encuentra en el orden Anura, los comúnmente conocidos como ranas y sapos, le sigue el orden Urodela (salamandras y por ultimo esta el Apoda (cecilias. En Colombia se han reportado 540 especies de anuros, pertenecientes a 56 géneros y 9 familias (Ruiz et 01., 1996. Por otra parte, entre las regiones de Colombia con mayor aporte a la diversidad de anuros esta la Cordillera Central. Estimulados por esta riqueza de anuros y dada las amplias zonas del país aún desconocidas a nivel de inventarios, entre ellas el municipio de Ibagué, el cual por su posición geográfica en la Cordillera Central y por su variedad de niveles altitudinales, ecosistemas y el hábitat para el albergue de los anuros, se llevó a cabo el presente estudio, con el propósito de reconocer el aporte de este municipio a la diversidad descrita con respecto a la Cordillera Central ya Colombia.

First evidence of tumor-like anomaly infestation in Copepods from the central Indian Ridge

Digital Repository Service at National Institute of Oceanography (India)

Bhandare, C.; Ingole, B.S.

manuscript. This is the contribution No. 4338 of NTO, Goa. References 1 Peralta P & Claps M. Plankton of a high mountain shallow lake (Los Horcones, High Los Andes Cordillera, Mendoza, Argentina). Verhandlungen der Int. Vereinigung fuer Theoretische und...

A New Species of Geotrigona(Hymenoptera: Apidae, Meliponini, with Comments on the Genus in Colombia

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Victor H. Gonzalez

2007-08-01

Full Text Available We describe the stingless bee Geotrigona kaba sp. nov. from the cordillera Central of Colombia. We also provide new geographical records and comments on the other two species of the genus that occur in Colombia.

Reptiles de zonas bajas de Yacopí (Cundinamarca, Colombia

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Rafael Ángel Moreno Arias

2006-01-01

Full Text Available Se efectuó un inventario de reptiles que ocurren por debajo de 1.000 m en el municipio de Yacopí, Cundinamarca, Colombia. Se registraron 47 especies (26 Sauria, 19 Serpentes, un Amphisbaenia y un Testudinata, la familia y género más ricos fueron Colubridae y Anolis. La riqueza entre Sauria y  Serpentes fue diferente a la que se encuentra en el país. La fauna se agrupó según su distribución en dos tipos:  Trasandino (al oeste de la cordillera Oriental y Amplio (tanto al este como al oeste de la misma cordillera, los Saurios fueron más numerosos en el primero y las Serpentes en el segundo. Se encontró que la mayoría de reptiles se distribuye entre 0 y 2.000 m.

Nueva especie y comentarios morfológicos y fitogeográficos en el género Aragoa H.B.K., (Scrophulariaceae Nueva especie y comentarios morfológicos y fitogeográficos en el género Aragoa H.B.K., (Scrophulariaceae

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Fernández Alonso José Luis

1991-06-01

Full Text Available Se describe una nueva especie del género Aragoa H.B.K. (Scrophulariaceae. A. romeroi  Fernández Alonso, propia de zonas subparamunas de la Sierra de Perijá, Cordillera Oriental, Colombia. Se subdivide el género en tres "grupos" de especies, comentándose su relación morfológica y fitogeográfica. Paralelamente se discute la ubicación de la nueva especie dentro del género. A new species of Aragoa H.B.K. (Scrophulariaceae, A. romeroi Fernández Alonso, characteristic of the subparamo zone of the Sierra de Perijá, Eastern Cordillera, Colombia is described. A division of the genus in three groups is made and their morphological and phytogeographical relationships are commented. Simultaneously, the location of the new species within the genus is discussed.

Four New Species of Nepenthes L. (Nepenthaceae from the Central Mountains of Mindanao, Philippines

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Thomas Gronemeyer

2014-06-01

Full Text Available Together with the islands of Sumatra (Indonesia and Borneo (Indonesia, Malaysia, the Philippines are the main center of diversity for carnivorous pitcher plants of the genus, Nepenthes L. Nepenthes are the largest of all carnivorous plants, and the species with the biggest pitchers are capable of trapping and digesting small amphibians and even mammals. The central cordillera of Mindanao Island in the south of the Philippines is mostly covered with old, primary forest and is the largest remaining cohesive, untouched area of wilderness in the Philippines. In a recent field exploration of two areas of the central cordillera, namely Mount Sumagaya and a section of the Pantaron range, four new taxa of Nepenthes were discovered. These four remarkable new species, N. pantaronensis, N. cornuta, N. talaandig and N. amabilis, are described, illustrated and assessed.

Constraints on deformation of the Southern Andes since the Cretaceous from anisotropy of magnetic susceptibility

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Maffione, Marco; Hernandez-Moreno, Catalina; Ghiglione, Matias C.; Speranza, Fabio; van Hinsbergen, Douwe J.J.; Lodolo, Emanuele

2015-01-01

The southernmost segment of the Andean Cordillera underwent a complex deformation history characterized by alternation of contractional, extensional, and strike-slip tectonics. Key elements of southern Andean deformation that remain poorly constrained, include the origin of the orogenic bend known

Efectos de la tectónica y el clima en la configuración morfológica del relieve costero del norte de Chile Tectonic and climatic effects in the morphologic configuration of the coastal relief of northern Chile

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Jorge Quezada

2010-01-01

Full Text Available En este trabajo se analiza el relieve de la vertiente occidental de la Cordillera de la Costa del norte de Chile, la cual está caracterizada por la ocurrencia del gran Acantilado Costero. El objetivo central de este estudio es establecer los controles tectónico-climáticos en la configuración del relieve del borde costero del norte de Chile. La metodología utilizada consiste básicamente en un estudio detallado del relieve mediante índices geomorfológicos cuantitativos tales como grado de incisión, curvas e integrales hipsométricas, perfiles de thalweg e índice de sinuosidad. Estos índices se aplicaron a modelos de elevación digitales e imágenes satelitales. Los resultados más relevantes muestran que el relieve de la vertiente occidental de la Cordillera de la Costa exhibe creciente incremento de la intensidad de la erosión al aumentar la latitud. Este incremento no es uniforme; procesos relacionados con la tectónica como subsidencia/alzamiento litoral y actividad de fallas, y por otra parte la erosión de la paleotopografía de la Cordillera de la Costa debido a los procesos ligados a la construcción del Acantilado Costero y el aumento de la precipitación, afectan la morfología del relieve del borde costero del norte de Chile. La existencia y excelente preservación del Acantilado Costero resulta de un marcado desequilibrio entre las tasas de alzamiento y las tasas de erosión, cuya diferencia es de una a dos órdenes de magnitud, controlada por el marco climático de hiperaridez extrema del Desierto de Atacama que se ha mantenido por lo menos desde los últimos 2 Ma. Las variaciones en la intensidad de la erosión desde el norte hacia el sur se interpretan como resultado del incremento en la tasa de precipitación en un orden de magnitud en esa misma dirección.This work analyzes the morphological features of the western margin of the northern Chile Coastal Cordillera, character-ized by the presence of a major Coastal Cliff

Streamflow responses in Chile to megathrust earthquakes in the 20th and 21st centuries

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Mohr, Christian; Manga, Michael; Wang, Chi-yuen; Korup, Oliver

2016-04-01

Both coseismic static stress and dynamic stresses associated with seismic waves may cause responses in hydrological systems. Such responses include changes in the water level, hydrochemistry and streamflow discharge. Earthquake effects on hydrological systems provide a means to study the interaction between stress changes and regional hydrology, which is otherwise rarely possible. Chile is a country of frequent and large earthquakes and thus provides abundant opportunities to study such interactions and processes. We analyze streamflow responses in Chile to several megathrust earthquakes, including the 1943 Mw 8.1 Coquimbo, 1950 Mw 8.2 Antofagasta, 1960 Mw 9.5 Valdivia, 1985 Mw 8.0 Valparaiso, 1995 Mw 8.0 Antofagasta, 2010 Mw 8.8 Maule, and the 2014 Mw 8.2 Iquique earthquakes. We use data from 716 stream gauges distributed from the Altiplano in the North to Tierra del Fuego in the South. This network covers the Andes mountain ranges, the central valley, the Coastal Mountain ranges and (mainly in the more southern parts) the Coastal flats. We combine empirical magnitude-distance relationships, machine learning tools, and process-based modeling to characterize responses. We first assess the streamflow anomalies and relate these to topographical, hydro-climatic, geological and earthquake-related (volumetric and dynamic strain) factors using various classifiers. We then apply 1D-groundwater flow modeling to selected catchments in order to test competing hypotheses for the origin of streamflow changes. We show that the co-seismic responses of streamflow mostly involved increasing discharges. We conclude that enhanced vertical permeability can explain most streamflow responses at the regional scale. The total excess water released by a single earthquake, i.e. the Maule earthquake, yielded up to 1 km3. Against the background of megathrust earthquakes frequently hitting Chile, the amount of water released by earthquakes is substantial, particularly for the arid northern

High risks of lung disease associated with early-life and moderate lifetime arsenic exposure in northern Chile

Energy Technology Data Exchange (ETDEWEB)

Steinmaus, Craig, E-mail: craigs@berkeley.edu [Arsenic Health Effects Research Program, UC Berkeley School of Public Health, Berkeley, CA (United States); Ferreccio, Catterina; Acevedo, Johanna [School of Medicine, Pontificia Universidad Católica de Chile, Santiago (Chile); Advanced Center for Chronic Diseases (ACCDiS), FONDAP, Santiago (Chile); Balmes, John R [Arsenic Health Effects Research Program, UC Berkeley School of Public Health, Berkeley, CA (United States); Department of Medicine, University of California, San Francisco, San Francisco, CA (United States); Liaw, Jane [Arsenic Health Effects Research Program, UC Berkeley School of Public Health, Berkeley, CA (United States); Troncoso, Patricia [Laboratorio de Anatomía Patológica Dra. Patricia Troncoso, Iquique (Chile); Hospital Felix Bulnes, Departmento de Anatomía Patológica, Santiago (Chile); Dauphiné, David C [Arsenic Health Effects Research Program, UC Berkeley School of Public Health, Berkeley, CA (United States); Nardone, Anthony [Global Health Sciences Program, University of California, San Francisco, San Francisco, CA (United States); Smith, Allan H [Arsenic Health Effects Research Program, UC Berkeley School of Public Health, Berkeley, CA (United States)

2016-12-15

Background: Arsenic in drinking water has been associated with increases in lung disease, but information on the long-term impacts of early-life exposure or moderate exposure levels are limited. Methods: We investigated pulmonary disease and lung function in 795 subjects from three socio-demographically similar areas in northern Chile: Antofagasta, which had a well-described period of high arsenic water concentrations (860 μg/L) from 1958 to 1970; Iquique, which had long-term arsenic water concentrations near 60 μg/L; and Arica, with long-term water concentrations ≤ 10 μg/L. Results: Compared to adults never exposed > 10 μg/L, adults born in Antofagasta during the high exposure period had elevated odds ratios (OR) of respiratory symptoms (e.g., OR for shortness of breath = 5.56, 90% confidence interval (CI): 2.68–11.5), and decreases in pulmonary function (e.g., 224 mL decrease in forced vital capacity in nonsmokers, 90% CI: 97–351 mL). Subjects with long-term exposure to arsenic water concentrations near 60 μg/L also had increases in some pulmonary symptoms and reduced lung function. Conclusions: Overall, these findings provide new evidence that in utero or childhood arsenic exposure is associated with non-malignant pulmonary disease in adults. They also provide preliminary new evidence that long-term exposures to moderate levels of arsenic may be associated with lung toxicity, although the magnitude of these latter findings were greater than expected and should be confirmed. - Highlights: • Based on its unique geology, lifetime arsenic exposure can be assessed in north Chile. • Signs and symptoms of lung disease were associated with early-life arsenic exposure. • Evidence of lung disease was also associated with moderate arsenic exposure.

The role of historical and local factors in determining species composition of the highland avifauna of Costa Rica and Western Panamá

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Gilbert Barrantes

2009-11-01

Full Text Available The formation of the mountain ranges of Costa Rica and western Panamá, as well as the cold climatic conditions that prevailed during the upper Pleistocene, played a crucial role in determining the bird species composition of the highlands in this region. Glacial conditions favored dispersal movements of bird species from the Andes, and from the Neartic region. Subsequent inter-glacial conditions reduced the connectivity between neotropical highlands (e.g., Talamanca-Andes, and between neotropical highlands and Neartic temperate region, isolating recently established populations from the ancestral populations, and promoting speciation. Within Costa Rica, the highland vegetation and the birds that occupied this vegetation possibly had a continuous distribution throughout all mountain ranges during glacial periods. This vegetation retreated to the summit of the mountains during inter-glacial periods, fragmenting the original continuous bird populations and forming "sky islands", which decrease in size from Talamanca mountains towards the northwestern ranges. The sizes of such islands of available habitat determine the number of highland birds present in each mountain range. Rev. Biol. Trop. 57 (Suppl. 1: 333-349. Epub 2009 November 30.La formación de las cordilleras en Costa Rica y oeste de Panamá, así como las frías condiciones climáticas que prevalecieron durante la última parte del Pleistoceno, jugaron un papel muy importante en determinar la composición de las especies de aves en las tierras altas de esta región. Las condiciones glaciales favorecieron la dispersión de aves desde los Andes y desde la región Neártica. Las subsecuentes condiciones inter-glaciales redujeron la conectividad entre las zonas altas neotropicales (e.g., Talamanca-Andes y entre las zonas altas neotropicales y la región templada Neártica, aislando así las poblaciones recientemente establecidas, de las poblaciones ancestrales, fomentando la especiaci

Sexual Scripts about Seduction, Eroticism and Sexual Encounters in the North of Chile

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Jimena Silva Segovia

2008-05-01

Full Text Available This article observes the diverse expressions of sexual encounters, seduction and eroticism in the North of Chile. The study was realized using the Sexual Scripts theory. We interviewed 46 men and women from 18 through 69 years of age from the cities of Antofagasta and Calama. The main conclusions reveal that the construction of the sexual scripts is reinforced by the sociocultural inequitable models and predominant gender relationships in the Chilean society, especially in that area, where mining is the most important economic activity. Moreover, in the lower socioeconomic levels we can find elements associated with the most traditional models, whereas sexual scripts with more flexible and equitable elements are found in higher socioeconomic strata.

Water column distribution of phospholipid-derived fatty acids of marine microorganisms in the Humboldt Current system off northern Chile

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Espinosa, Luisa F.; Pantoja, Silvio; Pinto, Luis A.; Rullkötter, Jürgen

2009-07-01

Suspended particulate matter samples from the oxygenated surface zone, the oxygen minimum zone, and the oxygenated deeper zone were collected from the upwelling area off Antofagasta in northern Chile during austral autumn (April 2001) to study the composition of microbial phospholipid-derived fatty acid methyl esters, using capillary gas chromatography-mass spectrometry. Whereas phytoplanktonic carbon dominated living organic matter near the coast, bacterial carbon was most abundant offshore. The biomarker distribution showed some differences between the depth levels sampled, such as the highest microbial abundance in the epipelagic zone represented by phytoplankton, especially diatoms, and a homogeneous distribution of bacterial biomarkers, with no indication of vertical segregation of functional groups as previously thought.

Oroclinal Bending and Mountain Uplift in the Central Andes

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Mpodozis, C.; Arriagada, C.; Roperch, P.

2007-05-01

The large paleomagnetic database now available for the Central Andes permits a good understanding of the overall spatial and temporal variations of rotations. Mesozoic to Early Paleogene rocks along the forearc of northern Chile (23°-28°S) record significant clockwise rotations (>25°) [Arriagada et al., 2006, Tectonics, doi:10.1029/2005TC001923]. Along the forearc of southern Peru, counterclockwise rotations recorded within flat lying red-beds (Moquegua Formation) increase from about -30° at 17.5°S to - 45° at15.5°S and decrease through time from the late Eocene to the late Oligocene-early Miocene [Roperch et al., 2006, Tectonics, doi:10.1029/2005TC001882]. Recently published thermo-chronological studies show evidence for strong exhumation within Bolivian Eastern Cordillera and the Puna plateau starting in the Eocene while structural studies indicate that the majority of crustal shortening in the Eastern Cordillera occurred during the Eocene-Oligocene, although the final stages of deformation may have continued through the Early Miocene. Rotations in the Peruvian and north Chilean forearc thus occurred at the same time than deformation and exhumation/uplift within the Eastern Cordillera. In contrast Neogene forearc rocks in southern Peru and northern Chile do not show evidences of rotation but low magnitude (10°) counterclockwise rotations are usually found in mid to late Miocene rocks from the northern Altiplano. These Neogene rotations are concomitant with shortening in the Sub-Andean zone and sinistral strike-slip faulting along the eastern edge of the northern Altiplano. We interpret the rotation pattern along the southern Peru and north Chile forearc as a result of strong late Eocene- late Oligocene oroclinal bending of the Central Andes associated with shortening gradients along the Eastern Cordillera associated both with the Abancay deflection and the Arica bend. The amount and spatial distribution of pre-Neogene shortening needed to account for

Endangering of the dam stability of Palcacocha Lake by slope movements, in Peru

Czech Academy of Sciences Publication Activity Database

Vilímek, V.; Zapata, M. L.; Klimeš, Jan; Patzelt, Z.; Santillán, N.

2005-01-01

Roč. 2, č. 2 (2005), s. 107-115 ISSN 1612-510X Grant - others:GA MŠk(CZ) LA 157 Institutional research plan: CEZ:AV0Z30460519 Keywords : landslides * glacial lakes * Cordillera Blanca Subject RIV: DC - Siesmology, Volcanology, Earth Structure

The advertisement call of Centrolene notostictum (Anura, Centrolenidae) with a new record of geographic distribution in Tolima, Colombia.

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Viuche-Lozano, Andres; Enciso-Calle, Maria Paula; Bernal, Manuel Hernando

2018-02-05

Centrolene notostictum Ruiz-Carranza Lynch,1991 is a glassfrog known from the Cordillera Oriental of Colombia-in the Departments of Boyacá, Cundinamarca, Norte de Santander and Santander (Frost 2017)-and the Venezuelan versant of the Sierra de Perijá (Rojas et al. 2012) from 1600 to 2440 masl. Although males have been found calling on the upper surface of the leaves of ferns and Heliconeaceae on the margins of a small fast-flowing stream (Rojas et al. 2012), no quantitative description of the advertisement call of C. notostictum is currently available. During fieldwork in the Galilea Natural Forest (on the western slope of Cordillera Oriental in the municipality of Villarrica, department of Tolima, Colombia) in 2016 and 2017, we found three vocalizing males of C. notostictum. Herein, we report the first geographic record of this species for the department of Tolima and describe its previously unknown advertisement call.

A new species of Silvinichthys (Siluriformes, Trichomycteridae) lacking pelvic fins from mid-elevation localities of the southern Andes, with comments on the genus.

Science.gov (United States)

Fernández, L; Sanabria, E A; Quiroga, L B; Vari, R P

2014-02-01

Silvinichthys huachi new species, is described from a stream along the lower slope of the Andean Cordillera in the Provincia de San Juan, Argentina. It shares the distinctive modifications characteristic of Silvinichthys, but is distinguished from the four previously described congeners by the combination of a lack of the pelvic fin and the pelvic girdle, details of pigmentation and various meristic and morphometric features. Silvinichthys huachi is apparently endemic to the type locality situated within an arid region of western central Argentina in the Andino Cuyana Province. Major gaps in the range of species of Silvinichthys may indicate that the origin of the genus predates the uplift events that subdivided drainages along the eastern slopes of the Andean Cordillera in west central Argentina. Silvinichthys huachi is hypothesized to be the sister species of Silvinichthys bortayro. © 2014 The Fisheries Society of the British Isles.

Palaeogene to Early Miocene sedimentary history of the Sierra Espuña (Malaguide complex, internal zone of the Betic cordilleras, SE Spain. Evidence for extra-Malaguide (Sardinian? provenance of oligocene conglomerates: Palaeogeographic implications

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Geel, T.

1996-12-01

Full Text Available The Sierra Espuña is situated at the northern edge of the Internal Zone in the eastern Betic Cordilleras and is part of the unmetamorphosed Malaguide Complex. Palaeontological and sedimentological analysis of the Eocene to Aquitanian sediments on the northwest side of the Espuña yielded unexpected new information of importance for the reconstruction of the history of the Espuña itself and the Malaguides in general. The socalled Upper Eocene (Auversian rocks are of Early Oligocene (P20 age and contain supermature detritus derived from outside the Malaguide realm. The hundreds of meters thick limestone conglomerate formation of the Espuña is of Middle Oligocene (P21 age and represents a backstepping fan delta complex at the margin of a carbonate platform situated to the northeast of the Espuña. Analysis of the clasts suggests that this platform was a part of the north Sardinian block given the majority of fragments of Upper Jurassic sheltered inner platform (Clypeina-Trocholina limestones and dolomites. Contrary to former views (Paquet, 1966; Lonergan, 1993, the conglomerates cannot be considered to be the erosional products of Malaguide imbricated units. Therefore, one of the main arguments for early (Late Eocene to Oligocene thrusting and nappe emplacement in the Espuña area is not valido Other arguments for early kinematics are discussed, among others the allegedly continuous sedimentation from the Late Eocene until the Langhian northwest of the Espuña. Our data indicate the existence of a stratigraphic gap, comprising the middle Aquitanian to middle Burdigalian. A new model for the development of the Espuña within the Malaguide realm during the Palaeogene to Early Miocene is presented. Main thrusting and nappe emplacement is thought to have been taken place during the late Aquitanian. Finally, the recently proposed 2000 clockwise rotation of the Espuña as a coherent block during the Early to Middle Miocene (AlIerton el al., 1993 is

Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

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Moscol Olivera, M.C.; Cleef, A.M.

2009-01-01

Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 in were examined along two altitudinal transects crossing the

UNA NUEVA ESPECIE DE SOLANUM SECCIÓN GEMINATA (SOLANACEAE DE COLOMBIA

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GRANADOS-TOCHOY JUAN CARLOS

2006-06-01

Full Text Available Se describe Solanum sagittantherum Granados-Tochoy & C.I. Orozco, una nuevaespecie de Solanum sección Geminata encontrada en la Cordillera Oriental de losAndes de Colombia. Se presenta información sobre su distribución, hábitat y taxonomía.

The paleobotanical record of Colombia: Implications for biogeography and biodiversity

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Hooghiemstra, H.; Wijninga, V.M.; Cleef, A.M.

2006-01-01

Plant microfossil and macrofossil associations obtained from six dated sections from the area of the basin of Bogota¿ (2550 m, Eastern Cordillera, Colombia) show the evolution of the late Neogene Andean montane forest, triggered by the Andean orogeny. Progressive adaptation of warm tropical taxa to

The dynamic history of the upper forest line ecotone in the northern Andes

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Hooghiemstra, H.; Berrio, J.C.; Groot, M.H.M.; Bogotá-A, R.G.; Moscol Olivera, M.; González-Carranza, Z.; Myster, R.W.

2012-01-01

In the Andean cordilleras very conspicuous ecotones can be found. The transition from continuous upper montane forest to treeless herbaceous vegetation, regionally known as "páramo" (Cleef 1981; Luteyn 1999) is known as the "upper forest line" (UFL) or "timber line" (Holtmeier 2009). Above the UFL

Vegetation composition and altitudinal distribution of Andean rain forests in El Angel and Guandera reserves, northern Ecuador

NARCIS (Netherlands)

Moscol Olivera, M.C.; Cleef, A.M.

2009-01-01

Patterns of vascular plant species composition and structure of the remaining rain forest of the Andean Cordillera in northern Ecuador were studied in two reserves: Guandera and El Angel. Thirty three plots located between 3300 and 3700 m were examined along two altitudinal transects crossing the

Biogeographic patterns of Colombian frogs and toads

International Nuclear Information System (INIS)

Lynch, John D.; Ruiz Carranza, Pedro M; Ardila Robayo, Maria Cristina

1997-01-01

Using the data provided in Ruiz-Carranza et al. (1996) the distributions of the 540 species of frogs and toads are partitioned among ten ecogeographic units of Colombia defined on the basis of precipitation and elevation. Some lowlands areas (pacific lowlands, Amazonian) exhibit high diversity (85-94 species) but lowlands areas in general are impoverished (30-52 species), especially when contrasted with upland areas. The three Andean cordilleras harbor between 87 and 121 species of frogs and toads, demonstrating that the biodiversity of Colombia resides primarily in its montane components, not in its lowland rain forests. When biological endemicity is separated from political endemicity, five areas of high endemicity remain (the three Andean cordilleras, the Sierra Nevada de Santa Marta, and the pacific lowlands). We endeavor to explain this description by recourse to cladistic analyses of several groups of leptodactylid frogs where we find that the general pattern of diversification is by means of horizontal diversification (allopatric speciation) with a minor contribution from vertical diversification

Colobanthus Quitensis (H.B.K. Bartl. (Caryophyllaceae en los Andes Colombianos

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Aguirre C. Jaime

1982-04-01

Full Text Available Colobantbus quitensis y Deschampsia antarctica son las dos únicas fanerogamas nativas presentes hoy dia en el continente antártico (Green, 1970. La primera tiene una distribución amplia en regiones templadas y frías de América Latina, desde la Tierra del Fuego hasta México (Moore, 1972.  En noviembre de 1978 se realizó una exploración geobotánica corta al Páramo Alto del Almorzadero en la Cordillera Oriental, Departamento de Santander; en el piso pantanoso de un vallecito a 3.900 m (El Tutal se encontraron algunas maticas dispersas de Colobanthus quitensis (biótipo laxa cerca de una corriente lenta de agua. El hallazgo anterior de Colobanthus quitensis en la región del Nevado del Ruiz en la Cordillera Central motivó la elaboración del presente trabajo, con el fin de dar a conocer los caracteres morfológicos, palinológicos y sociológicos de esta interesante especie.

Especie nueva de Scybalocanthon (Coleoptera: Scarabaeinae: Canthonini y descripción de la variación del órgano genital masculino A new species of Scybalocanthon (Coleoptera: Scarabaeinae: Canthonini and description of the variation of the male genitalia

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Fredy Molano Rendón

2010-12-01

Full Text Available Se describe Scybalocanthon arcabuquensis Molano y Medina, sp.nov. La distribución de esta especie se encuentra restringida a los bosques de roble del municipio de Arcabuco, Departamento de Boyacá, sobre la cordillera Oriental de los Andes en Colombia. El órgano genital del macho se describe e ilustra, se discute la variación de las estructuras del saco interno de varias especies del género, y se proponen algunas estructuras del órgano genital como posibles caracteres únicos que definen el género.Scybalocanthon arcabuquensis Molano y Medina, sp. nov. is described. The species is restricted to the oak forest at Arcabuco municipality, department of Boyacá, Eastern Cordillera of the Colombian Andes. The male genitalia is described and illustrated, the variation of structures of the internal sac is discussed for various species of the genus and some structures from the internal male genitalia are proposed as possible unique characters useful for defining the genus.

Geologic sources of energy

Science.gov (United States)

Bundtzen, Thomas K.; Nokleberg, Warren J.; Bundtzen, Thomas K.; Nokleberg, Warren J.; Price, Raymond A.; Scholl, David W.; Stone, David B.

2017-01-01

This chapter describes the exploration, development, and geologic setting of petroleum resources (including tar sands), coal resources (including coalbed methane), and geothermal energy resources of the Northern Cordillera.For petroleum resources, the chapter describes: (1) the history of petroleum development and production, first for Alaska and then for the Canadian Cordillera; and (2) generalized basin analysis geologic settings for the six major petroleum basins that are illustrated in summary maps and cross sections. Subsequent sections of the chapter describe the nature and geologic setting of tar sand resources, geothermal energy resources, and coal resources. The area distribution of the energy resources of the region are depicted in the Energy Resources Map that has multiple layers that can be displayed in various arrangements. Employing this map in a separate window while reading the text will be greatly beneficial. Many geographic names are employed in the descriptions throughout this chapter. While reading this chapter, viewing the Geographic Regions Layer of the Energy Resources Map, as needed, will be valuable.

Estructura y composición florística de tres robledales en la región norte de la cordillera central de Colombia

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Juan D León

2009-12-01

Full Text Available La alta diversidad florística que albergan los ecosistemas andinos está siendo amenazada por fuertes presiones de origen antrópico. Uno de estos ecosistemas son los robledales, bosques dominados por la especie Quercus humboldtii, que se encuentra seriamente amenazada en Colombia porque su madera es valiosa comercial y dendroenergéticamente. En este estudio, se caracterizó la composición florística y la estructura de tres robledales de los Andes colombianos, con el fin de determinar su similaridad. En cada sitio, se estableció una parcela permanente (5 000 m² donde se muestrearon todos los árboles con D ≥ 10 cm. En los tres sitios, la especie dominante fue Q. humboldtii, pero la similitud florística entre ellos no fue alta. La estructura por clases de tamaño para los tres sitios fue en forma de J invertida, aunque varió la abundancia de individuos por clase diamétrica. Los resultados indican que los robledales estudiados difieren en su composición florística y estructura a pesar de presentar características biofísicas similares. Las diferencias encontradas se deben posiblemente, a los diferentes factores que interactúan en cada sitio como la historia de uso, intensidad y duración de las perturbaciones antrópicas pasadas, topografía, fauna y clima local, que se ven reflejados en los parámetros estructurales de la vegetación.Structure and floristic composition of three oak forests in the northern region of the Central Cordillera in Colombia. Andean ecosystems harbor a high floristic diversity, which is being threatened by human disturbances such us deforestation and by the expansion of the agricultural frontier. One of these ecosystems are the Andean oak forests dominated by Quercus humboldtii, a threatened species in Colombia. We assessed the floristic composition and structure of three Andean oak forests located in three localities (San Andrés de Cuerquia, Belmira and Guarne of Antioquia. The main goal was to determine

THE MODERN RACISM SCALE: PSYCHOMETRIC

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MANUEL CÁRDENAS

2007-08-01

Full Text Available An adaption of McConahay, Harder and Batts’ (1981 moderm racism scale is presented for Chilean population andits psychometric properties, (reliability and validity are studied, along with its relationship with other relevantpsychosocial variables in studies on prejudice and ethnic discrimination (authoritarianism, religiousness, politicalposition, etc., as well as with other forms of prejudice (gender stereotypes and homophobia. The sample consistedof 120 participants, students of psychology, resident in the city of Antofagasta (a geographical zone with a highnumber of Latin-American inmigrants. Our findings show that the scale seems to be a reliable instrument to measurethe prejudice towards Bolivian immigrants in our social environment. Likewise, important differences among thesubjects are detected with high and low scores in the psychosocial variables used.

The caves of Cunday (Colombia, South America)

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Hammen, van der Th.; Nelson, H.W.

1955-01-01

A short time ago rumors reached Bogota that a big cavesystem had been discovered by some farmers in the southwest of the department of Tolima, between the villages of Cunday and Purificación. This region belongs morphologically and geologically to the Eastern Cordillera, and forms the westernmost

Aptychi from the Berriasian/Valanginian (France and Spain): New stratigraphical and morphological details

Czech Academy of Sciences Publication Activity Database

Vašíček, Zdeněk; Janssen, N. M. M.; Klein, J.

2016-01-01

Roč. 86, č. 3 (2016), s. 265-272 ISSN 0208-9068 Institutional support: RVO:68145535 Keywords : Lamellaptychi * Berriasian/Valanginian * Vocontian Basin * Betic Cordillera Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.833, year: 2016 http://www.asgp.pl/sites/default/files/volumes/86_3_265_272.pdf

Lamellaptychi from the Lower Cretaceous of south-east Spain (Murcia and Jaen provinces)

Czech Academy of Sciences Publication Activity Database

Vašíček, Zdeněk; Company, M.; Měchová, L.

2015-01-01

Roč. 276, č. 3 (2015), s. 335-351 ISSN 0077-7749 Institutional support: RVO:68145535 Keywords : Lower Cretaceous * aptychi * ammonite zonation * Betic Cordillera Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.719, year: 2015 http://cretaceous.ru/files/pub/temp3/vasicek_et_al_2015_lamellaptychi.pdf

The species of the genus Pseudoniphargus Chevreux, 1901 (Amphipoda) from northern Spain

NARCIS (Netherlands)

Notenboom, Jos

1986-01-01

Based on new material collected in 1983, 1984, and 1985, the genus Pseudoniphargus proves to be distributed in northern Spain from Asturias, in the western part of the Cordillera Cantabrica, to Navarra and Huesca, in the headlands of the Pyrenees; and from coastal Atlantic regions up to the northern

Pliocene-Lower Pleistocene shallow-water mixed siliciclastics and carbonates (Yanigua and Los Haitises formations) in eastern Hispaniola (Dominican Republic)

Science.gov (United States)

Braga, Juan C.; Díaz de Neira, Alberto; Lasseur, Eric; Mediato, José; Aguirre, Julio; Abad, Manuel; Hernaiz-Huerta, Pedro P.; Monthel, Jacques; Pérez-Valera, Fernando; Lopera, Eusebio

2012-07-01

The virtually unfolded sedimentary cover of the Cordilleras Central and Oriental in the eastern Dominican Republic (eastern Hispaniola, tropical North Atlantic) largely consists of Pliocene to Early Pleistocene mixed siliciclastics and carbonates. These deposits have been grouped into two laterally interfingering mapping units, the Yanigua and Los Haitises formations. The former (mainly siliciclastics) comprises marl, marly limestone, and minor conglomerate, sandstone, lignite, and carbonaceous clay and crops out closest to the basement. The Los Haitises Formation mainly consists of limestone and intercalating beds of marly limestone and marl. Lithological mapping at the 1:50,000 scale and facies analysis of twelve measured sections and of additional fourteen outcrops suggest that these deposits mainly formed on a shallow-water marine platform fringing the precursor reliefs of the Cordillera Oriental and the southeastern end of the Cordillera Central. Only a limited proportion of sediment formed in floodplains and marshes. Marl and marly limestone dominated the inner platform sediments. Terrigenous mud decreased away from the emergent basement and carbonate sedimentation dominated the more external platform. Corals, molluscs, echinoids, foraminifers, bryozoans, coralline algae, and Halimeda are the main components with varying amounts of carbonate mud. The platform was generally a low-energy environment with seagrass patches. In the inner platform, corals grew as isolated colonies or as small patch reefs dominated by Porites in marly and bioclastic substrates. Branching corals (Stylophora and Acropora) grew in extensive carpets in more distal areas. At least in the last stage of its development (Early Pleistocene), the platform was rimmed by a reef barrier similar to the Holocene Caribbean barrier reefs, with Acropora gr. palmata, A. cervicornis, Porites, Montastrea, Siderastrea, and Diploria as the main reef builders.

Pinus sylvestris L. subsp. nevadensis (Christ Heywood in southern Spain: An endangered endemic Mediterranean forest

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Olmedo-Cobo Antonio José

2017-01-01

Full Text Available Pinus sylvestris subsp. nevadensis is the most endangered pine in Spain. This taxon takes refuge in only two massifs of the Betic Cordillera -Sierra Nevada and Sierra de Baza-, where its forests represent the southernmost limit of the species global distribution, surviving under conditions of geographic, demographic and ecological marginality in the upper treeline boundary that makes them very vulnerable to any environmental change or external aggression. This research establishes for the first time, and for the entire Betic Cordillera, the locations and ecological patterns of these pine forests, their plant dynamic and floristic composition, and provides an updated map of the current and potential distribution area of this subspecies. The methodological process for this research has consisted of an integrated phytosociological and biogeographical analysis of vegetation and the resulting landscape, through fieldwork covering in as much detail as possible the distribution area of P. sylvestris in the Betic Cordillera, and a review of the bibliographic background. Taking into account the results, P. sylvestris subsp. nevadensis forests survive at present under hostile Mediterranean conditions due to the special physical characteristics of the microenvironments in which they have taken refuge, mainly the cool, relatively moist climate of their ecological niches and the relatively impermeable soils that forests occupy. However, there are significant ecological obstacles for the future preservation of this pine in southern Spain, and therefore it is necessary for the creation of programmes to protect these threatened endemic and post-glacial relict forests through continued monitoring of their evolution and further research studying the processes that make this ecosystem as a whole so unique and valuable.

Desarrollo de cronologías de ancho de anillos para alerce (Fitzroya cupressoides en Contao y Mirador, Chile Development of tree-ring chronologies for alerce (Fitzroya Cupressoides in Contao and Mirador, Chile

Directory of Open Access Journals (Sweden)

EDUARDO NEIRA

2000-12-01

Full Text Available Se desarrollaron dos cronologías de ancho de anillos de crecimiento a partir de muestras de alerce (Fitzroya cupressoides (Molina Johnston, colectadas en dos sitios: Contao, Cordillera de los Andes (41º 33'S, 72º 38'W, y Mirador, en la Cordillera de la Costa (40º 10'S, 73º 42'W. En la elaboración de las cronologías se utilizó el programa COFECHA para verificar el cofechado y se desarrolló para cada sitio una cronología utilizando el programa computacional ARSTAN. Se compararon las cronologías Contao y Mirador, con otras existentes para alerce encontrándose una alta similitud de la cronología Contao con la desarrollada para Lenca (41º 33'S, 72º 36' W. Contao presentó los valores más altos en los estadígrafos analizados con relación a las demás cronologías. Se observaron diferencias entre las cronologías provenientes de la Cordillera de la Costa y de los Andes en los últimos 150 años, probablemente producto de explotaciones humanas e incendios ocurridos en la cordillera de la Costa. La correlación con variables climáticas fue similar en su tendencia a la de otros estudios previos, documentando una correlación negativa con las temperaturas y positiva con las precipitaciones del verano anterior al período de crecimientoTwo ring-width chronologies were developed using samples from alerce (Fitzroya cupressoides (Molina Johnston. These were collected from two different sites; Contao, in the Andean Range and Mirador, in the Coastal Range. The series from the each site were cross-dated and COFECHA program was used to verify this process. Once correctly cross-dated, ARSTAN program was used to build up a chronology for each site (Contao and Mirador. These chronologies were compared with other existing chronologies. Contao presented the best statistics when compared to the other chronologies. Differences between chronologies from the Coastal and Andes Ranges were detected mainly during the last 150 years. Before this period

Evolution and outburst risk analysis of moraine-dammed lakes in the ...

Indian Academy of Sciences (India)

negative mass balance but is consistent with the rapid expansion of the ... nities and cities, resulting in great loss of life and the ... Cascades, western North America; the Cordillera. Blanca, Peru; central Asia; and the central and ... loss of life and property downstream. ..... This work was funded by National Social Sci-.

Species richness and origin of the bryophyte flora of the Colombian Andes

NARCIS (Netherlands)

Gradstein, S.R.; Reenen, van G.B.A.; Griffin, D.

1988-01-01

Based on data from the ECOANDES project, a phytogeographical analysis has been made of the bryophyte flora along the wet, foggy western slope (1000-4500 m) and the drier eastern slope (500-4500 m) of the Colombian Central Cordillera at the ‘Parque de los Nevados’. Species richness increases with

A Holocene pollen record of vegetation change and human impact from Pantano de Vargas, an intra-Andean basin of Duitama, Colombia

NARCIS (Netherlands)

Gomez, A.; Berrio, J.C.; Hooghiemstra, H.; Becerra, M.; Marchant, R.

2007-01-01

Holocene environments in the intra-Andean basin of Duitama (Eastern Cordillera of Colombia, 2510 m altitude) are presented based on the 620 cm long Vargas pollen and sediment record. Seven AMS radiocarbon dates show these lake and swamp sediments represent the period from 8800 to 2610 14C yr BP. We

Late Pleistocene and Holocene activity of the Atacazo-Ninahuilca Volcanic Complex (Ecuador)

NARCIS (Netherlands)

Hidalgo, Silvana; Monzier, Michel; Almeida, Eduardo; Chazot, Gilles; Eissen, Jean-Philippe; van der Plicht, Johannes; Hall, Minard L.

2008-01-01

The Atacazo-Ninahuilca Volcanic Complex (ANVC) is located in the Western Cordillera of Ecuador, 10 km southwest of Quito. At least six periods of Pleistocene to Holocene activity (N1 to N6) have been preserved in the geologic record as tephra fallouts and pyroclastic flow deposits. New field data,

Geomorphologic impacts of the glacial lake outburst flood from Lake No. 513 (Peru)

Czech Academy of Sciences Publication Activity Database

Vilímek, V.; Klimeš, Jan; Emmer, A.; Benešová, M.

2015-01-01

Roč. 73, č. 9 (2015), s. 5233-5244 ISSN 1866-6280 R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : GLOF * debris flow * natural hazard * deglaciation * Cordillera Blanca * Peru Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 1.765, year: 2014

A Preliminary Study of Riparian Songbirds in Costa Rica, with Emphasis on Wintering Louisiana Waterthrushes

Science.gov (United States)

Terry L. Master; Robert S. Mulvihill; Robert C. Leberman; Julio Sanchez; Ernesto Carmen

2005-01-01

We made preliminary observations on the winter distribution, ecology and behavior of Louisiana Waterthrushes (Seiurus motacilla) in Costa Rica during January 1999 and 2000. We visited 24 headwater streams in three of the four principal mountain ranges in the country (Cordilleras Tilarán, Central, and the Talamanca) and confirmed the...

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

Science.gov (United States)

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

2012-04-01

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

Consecuencias del retroceso glaciar en la Cordillera boliviana

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Hoffmann, D.

2008-12-01

Full Text Available Glaciers have proven to be an excellent indicator of climate variations throughout the Holocene there are a number of studies on the recent trend towards disappearance of Bolivian glaciers. But at present, practically no research has been carried out on the consequences the melting and eventual disappearance of the country’s glaciers has and might have on the economic and social situation of its population. Thus, this country study on socio-economic impacts of glacier retreat is a first approach to get an overview of what and where might be expected in the future. Bolivian glaciers represent around 20% of the world’s tropical glacier area (Jordan 1991. The increased melting and disappearance started at the beginning of the 80s, with another increase during the last 5-10 years. Thus it is probable that most of the smaller glaciers which have not already vanished will have completely disappeared within 10 to 20 years from today. Impacts of glacier retreat are most likely to be mainly local, in some cases regional, which means that local authorities must play a vital role in this context. The supply of (drinking water for the growing urban conglomeration La Paz – El Alto, is the main issue with shrinking glaciers in Bolivia.

A la fecha existe un importante número de estudios que demuestran la tendencia actual hacia la desaparición de los glaciares bolivianos. El presente estudio del impacto socio-económico del retroceso de los glaciares es un primer intento de obtener un panorama sobre dónde y qué cambios se podría esperar en un futuro cercano. Aproximadamente el 80% de los glaciares bolivianos tienen una superficie menor a 0,5 km^²; por lo tanto, es muy probable que la mayoría de ellos hayan desaparecido completamente durante los próximos 10 a 15 años. Los impactos socio-económicos se harán notar sobre todo en un nivel local, y los elementos más preocupantes son, por un lado, la falta de investigación sobre el tema y por otro, la falta de una conciencia pública sobre el problema en la población boliviana y que una parte socio-políticamente importante y numerosa de la población será probablemente más afectada, la metrópoli La Paz – El Alto.

Steady-state exhumation pattern in the central Andes SE Peru

NARCIS (Netherlands)

Ruiz, G.M.H.; Carlotto, V.; van Heiningen, P.S.; Andriessen, P.A.M.

2009-01-01

The Western Cordillera of SE Peru is part of the Central Andes and is situated to the west of the Eastern Andes from which it is separated by the northern termination of the Altiplano - the Inter-Andean Valley. It is a volcanic-volcano-detrital chain that developed in the Palaeogene, and is

Fostering Early Math Comprehension: Experimental Evidence from Paraguay

Science.gov (United States)

Naslund-Hadley, Emma; Parker, Susan W.; Hernandez-Agramonte, Juan Manuel

2014-01-01

Research indicates that preschool children need to learn pre-math skills to build a foundation for primary- and secondary-level mathematics. This paper presents the results from the early stages of a pilot mathematics program implemented in Cordillera, Paraguay. In a context of significant gaps in teacher preparation and pedagogy, the program uses…

¿Es posible la integración residencial en las ciudades chilenas?: Disposición de los grupos medios y altos a la integración con grupos de extracción popular

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Francisco Sabatini

2012-09-01

Full Text Available Con relativa independencia de su nivel social, edad y sexo, los residentes de las ciudades chilenas de Santiago, Antofagasta y Temuco muestran una significativa disposición a la integración residencial con personas de otra condición social. Sin embargo, dicha valoración de la integración enfrenta, por una parte, obstáculos y temores concretos (como el menoscabo a las plusvalías o respecto de la formación de los hijos que dificultan que se materialice en barrios menos segregados; y por otra, actitudes y conductas "clasistas". En términos prácticos, esta cultura urbana tensionada y ambivalente, junto a la relativa asimetría que presenta la segregación residencial entre sus dimensiones principales en el medio latinoamericano y a la prevalencia de una mezcla de indiferencia y tolerancia en la relación con el "otro", propia de las ciudades modernas, otorgarían viabilidad cultural a futuras políticas de reducción de la segregación.With relative independence of their social level, age or sex, the residents of the Chilean cities of Santiago, Antofagasta and Temuco show a significant disposition to residential integration with people of different social conditions. However, this positive evaluation of integration is confronted by concrete obstacles and fears (like the possible damage to the value of their properties or to the education of their children that make the materialization of less segregated neighborhoods harder, on the one hand, and "classist" attitudes and conducts, on the other. In practical terms, this ambivalent urban culture, together with a relative assymetry of residential segregation are the main dimensions in the Latin American context. These, together with a mixture of indifference and tolerance towards the "other", which are characteristic of modern cities, give cultural viability to future policies for the reduction of segregation.

EL ACRE Y LOS "ASUNTOS DEL PACÍFICO: BOLIVIA, BRASIL, CHILE Y ESTADOS UNIDOS, 1898-1909

Directory of Open Access Journals (Sweden)

Cristián Garay Vera

2008-12-01

Full Text Available Este trabajo sitúa el problema de la guerra del Acre en un contexto multilateral, reconociendo la vigencia del equilibrio de poder como parte del razonamiento de la conducción de las políticas exteriores en juego. Se aplica el concepto de frontera de F. J. Turner, para explicar cómo las fronteras permeables pusieron a Brasil y Bolivia en confrontación, por la maniobra boliviana de configurar una concesión a inversionistas estadounidenses, británicos y franceses, que fue interpretada por Brasil como una maniobra imperialista de Estados Unidos. Entones Brasil se acercó a Chile, y afrontaron juntos los problemas del Acre y de Antofagasta, que derivaron en las redacciones de los tratados de Petrópolis (1903 y de Paz y Amistad (1904. El artículo postula que Bolivia procedió de esta forma para impedir el avance brasileño, peruano y paraguayo sobre sus fronteras, y que la búsqueda del paraguas estadounidense fue una idea que Bolivia gestó para compensar el desequilibrio de poder.This work considers the Acre War as part of a multilateral context where the equilibrium of power was important in the reasoning behind the establishment of foreign relations. It uses the frontier concept developed by F. J. Turner to explain why their open frontier put Brazil and Bolivia in confrontation. This happened because of the Bolivian strategy of granting land to investors from the United States, Great Britain and France, which was interpreted by Brazil as an imperialist action promoted by the United States. This explains why Brazil established a cióse relationship with Chile to confront together their problems in Acre and Antofagasta, which led to the drafting of the Petrópilis (1903 and Paz y Amistad (1904 treaties. The article argues that Bolivia proceeded this way to avoid a Brazilian, Peruvian or Paraguayan territorial advance, seeking the support of the United States to compénsate the imbalance of power.

Biomarkers for screening of lung cancer and pre-neoplastic lesions in a high risk Chilean population

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Marta I Adonis

2014-01-01

Full Text Available BACKGROUND: The mortality of lung cancer (LC, increases each year in the world, in spite of any advances, in development of new drugs to advance stages of LC. The high incidence of LC has been associated with smoking habit, genetic diversity and environmental pollution. Antofagasta region has been reported to have the highest LC mortality rate in Chile and its inhabitants were exposed to arsenic in their drinking water in concentrations as high as 870 μg/L. Non-invasive techniques such as biomarkers (Automatic Quantitative Cytometry: AQC and DR70 and Auto Fluorescence Bronchoscopy (AFB might be potentially useful as a supplementary diagnostic approach and early detection. Early detection is one of the most important factors to intervene and prevent cancer progression in LC. This is a work of an ongoing prospective bimodality cancer surveillance study in high risk LC volunteers. Enrolment was done in subjects from Antofagasta and Metropolitan regions. In addition, we enrolled subjects who were suspected of having lung cancer. AQC, DR70 and AFB were used as tools in the detection of pre-neoplastic (PNL and neoplastic lesions (NL. RESULTS: Half of the samples, classified as suspicious by AFB, were confirmed as metaplasia or dysplasia by histopathology. For LC, DR70 showed a higher sensitivity (95.8% and specificity (91.9% than AQC. However, for PNL AQC showed a higher sensitivity (91.9% than DR70 (27.3%, although both with low PPV values. As a pre screener, both biomarkers might be employed as complementary tools to detect LC, especially as serially combined tests, with a sensitivity of 60% and a PPV of 65.2%. Additionally, the use of parallel combined tests might support the detection of PNL (sensitivity 91.2%; PPV 49.1%. CONCLUSION: This work adds information on cellular and molecular biomarkers to complement imaging techniques for early detection of LC in Latin America that might contribute to formulate policies concerning screening of LC

Overview about polluted sites management by mining activities in coastal-desertic zones

Science.gov (United States)

Reyes, Arturo; Letelier, María Victoria; Arenas, Franko; Cuevas, Jacqueline; Fuentes, Bárbara

2016-04-01

In Chile the main mining operations as well as artisanal and small-scale mining (copper, gold and silver) are located in desert areas. A large number of abandoned polluted sites with heavy metals and metalloids (Hg, Pb, Cu, Sb, As) remain in coastal areas close to human centers. The aim of this work was to identify the best remediation alternatives considering the physic-chemical characteristics of the coastal-desertic soils. The concentrations of above mentioned pollutants as well as soil properties were determined. The results showed variable concentration of the pollutants, highest detected values were: Hg (46.5 mg kg-1), Pb (84.7 mg kg-1), Cu (283.0 mg kg-1), Sb (90 mg kg-1), As (2,691 mg kg-1). The soils characteristic were: high alkalinity with pH: 7.75-9.66, high electric conductivity (EC: 1.94-118 mScm-1), sodium adsorption ratio (SAR: 5.07-8.22) and low permeability of the soils. Coastal-desertic sites are potential sources of pollution for population, and for terrestrial and marine ecosystems. Exposure routes of pollution for the population include: primary, by incidental ingestion and inhalation of soil and dust and secondary, by the ingestion of marine sediments, sea food and seawater. Rehabilitation of coastal-desertic sites, by using techniques like soil washing in situ, chemical stabilization, or phytostabilization, is conditioned by physic-chemical properties of the soils. In these cases the recommendation for an appropriate management, remediation and use of the sites includes: 1) physic chemical characterization of the soils, 2) evaluation of environmental risk, 3) education of the population and 3) application of a remediation technology according to soil characteristic and the planned use of the sites. Acknowledgments: Funding for this study was supported by the Regional Council of Antofagasta under Project Estudio de ingeniería para la remediación de sitios abandonados con potencial presencia de contaminantes identificados en la comuna de

Murciélagos de cola corta (Carollia: Phyllostomidae del Parque Nacional Natural Gorgona (Colombia y sus implicaciones biogeográficas

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Oscar E Murillo-García

2014-02-01

Full Text Available La identidad de la especie de Carollia (Chiroptera: Phyllostomidae en el Parque Nacional Natural Gorgona ha sido controvertida debido a la alta similitud entre C. perspicillata y C. brevicauda. C. perspicillata es la especie con mayor probabilidad de habitar en la isla debido a que actualmente se distribuye en las tierras bajas de la costa pacífica colombiana, mientras C. brevicauda es una especie predominantemente de tierras altas. Con el objetivo de resolver la controversia acerca de la especie del género Carollia que habita la isla, se realizaron análisis morfométricos con base en característica de cráneos y mandíbulas de especímenes de las dos especies y del PNN Gorgona. Los resultados evidenciaron que, contrario a lo esperado, esta población insular es morfológicamente más similar a C. brevicauda. Evidencia biológica para diferentes grupos de organismos sugiere que Gorgona puede haber estado conectada a los andes y las zonas bajas del pacífico del sur de Colombia-norte de Ecuador en el pasado. Por otra parte, existe evidencia geológica que muestra que Gorgona es la parte más alta de una cordillera (Cordillera de la Costa que se encuentra sumergida actualmente, pero que probablemente fue parte del continente durante el Pleistoceno. Por lo tanto, con base en esta evidencia biológica y geológica se plantea la hipótesis de una ruta de colonización de C. brevicauda a Gorgona desde los Andes a través de la Cordillera de la Costa. Este proceso pudo facilitarse por el descenso marino durante las glaciaciones del Pleistoceno.

The 11 May 2011 earthquake at Lorca (SE Spain) viewed in a structural-tectonic context

NARCIS (Netherlands)

Vissers, R.L.M.; Meijninger, B.M.L.

2011-01-01

The Lorca earthquake of 11 May 2011 in the Betic Cordillera of SE Spain occurred almost exactly on the Alhama de Murcia fault, a marked fault that forms part of a NE-SW trending belt of faults and thrusts. The fault belt is reminiscent of a strike-slip corridor, but recent structural studies have

Glacier-related landforms and glacial lakes in Huascarán National Park, Peru

Czech Academy of Sciences Publication Activity Database

Vilímek, V.; Klimeš, Jan; Červená, L.

2016-01-01

Roč. 12, č. 1 (2016), s. 193-202 ISSN 1744-5647 R&D Projects: GA ČR(CZ) GAP209/11/1000 Institutional support: RVO:67985891 Keywords : moraines * rock glaciers * glacial lakes * Cordillera Blanca * Huascarán National Park * Peru Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 2.174, year: 2016

Conversaciones sobre el litoral cordillerano

OpenAIRE

Browne,Enrique; Browne,Tomás

2009-01-01

Dos arquitectos dialogan sobre los Andes desde su propia vivencia. El territorio de Chile se entiende como límite natural entre mar y cordillera, donde suceden apretadamente una serie de eventos particulares: fallas geológicas, cerros que penetran en las ciudades y torrentes que bajan al mar caracterizan y diferencian sus paisajes.

On Chilean Loxosceles (Araneae: Sicariidae: first description of the males of L. surca and L. coquimbo, new records of L. laeta and three remarkable new species from coastal deserts

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Antonio D. Brescovit

2017-12-01

Full Text Available Loxosceles Heineken & Lowe, 1832 spiders are infamous for their medical importance, but a taxonomic picture of the genus is still far from complete. In this study, the Chilean species of Loxosceles are described and mapped. The males of Loxosceles surca Gertsch, 1967 and L. coquimbo Gertsch, 1967 are described for the first time. Three new species with narrow distributions are described from central and northern Chile: Loxosceles diaguita sp. nov. from the Antofagasta Region, L. pallalla sp. nov. from Coquimbo and L. vallenar sp. nov. from Atacama. The first two species are remarkable in their morphology and do not fit into any of Gertsch’s species groups, suggesting that Chile still harbours an undiscovered phylogenetic diversity of the genus. New distribution records for Loxosceles laeta (Nicolet, 1849 are provided throughout Chile.

Add to the ambiguity of the word body. An exercise from the sexuality of young miner northern Chile.

Directory of Open Access Journals (Sweden)

Carolina Ferrante

2013-12-01

Full Text Available En este trabajo se reseña y analiza la reciente publicación editada por Jimena Silva Segovia y Leyla Mendez Caro (2013 Cuerpos y Metáforas. Estudio de los significados culturales del cuerpo y las sexualidades juveniles,  Antofagasta: Ediciones Universidad Católica del Norte, Observatorio Regional de Desarrollo Humano.  Tal libro es el resultado del Proyecto FONDECYT 1110301, a cargo de la Dra. Jimena Silva Segovia. A lo largo de los capítulos que componen el trabajo una densidad en la mirada transversaliza la lectura: la recuperación del carácter ambiguo del cuerpo. Este elemento convierte a este excelente texto en material de consulta para todo investigador del campo de la sociología del cuerpo y las emociones.

Sedimentologic indicators of the Miocene tectonic evolution in the Nunchia syncline

International Nuclear Information System (INIS)

Ramirez Arias, Juan Carlos; Mora, Andres; Parra, Mauricio

2010-01-01

The study area corresponds to the Nunchia syncline, which is located in the eastern foothills of the eastern cordillera of Colombia. This structure is bounded by the Yopal thrust to the east, and Guaicaramo thrust to the west. This syncline has mostly outcrops of Miocene units, which belong to the Carbonera (C1-C5), Leon and Guayabo formations. Here we use sedimentologic data, especially in the Guayabo Formation, in order to determine the influence of active tectonics during its deposition. Petrographic analyses of sandstones indicate the presence of components associated with upper Cretaceous - Paleocene formations in the eastern cordillera. Paleocurrent orientation shows a preferential trend towards the se during the deposition of most of the studied formations, with a reversal in flow direction towards the W-NW during the deposition of the middle Guayabo Formation preserved in the Nunchia syncline. The collected data allows establishing a structural evolution in the Nunchia syncline which was therefore active during most of the Miocene. This evolution appears to be continuous, although fragmentation of the geological record shows more specific periods of tectonic activity.

Environmental variables, remote sensing and geographical information systems applied to the study of Rhodnius prolixus distribution in Colombia

International Nuclear Information System (INIS)

Guhl, Felipe

2010-01-01

A data base of the entomological survey performer during the Chagas Disease National Control Programme (CHDNCP) in 1997 - 2001 and temporal satellite images masp containing 57 environmental variables were used to build Rhodnius prolixus dispersion predictive maps in Colombia, based on temporal images, Fourier analyses and a discriminative multivaried statistical analyses of the variables studied. The maps show the dispersion of this species and its implication on the Chagas disease transmission in Colombia. A clear division in the predictive dispersion of R. prolixus in two geographical zones was found: one area in the southeast of the Eastern Cordillera associated with the environmental variables used in the present study and a second zone in the Andean Valleys, East of the Eastern Cordillera not much defined by the same variables. This would suggest that the Southwest Region. of Colombia presents a tendency to a wider dispersion of R. prolixus associated to other variables like human intervention. Sylvatic populations of R. prolixus were found recently in Attalea butyracea palm trees in this Region of the Eastern Planes demonstrating the prediction of the presence of this species.

Copper removal from contaminated soils by soil washing process using camellian-derived saponin

Science.gov (United States)

Reyes, Arturo; Fernanda Campos, Maria; Videla, Álvaro; Letelier, María Victoria; Fuentes, Bárbara

2015-04-01

Antofagasta Region in North of Chile has been the main copper producer district in the world. As a consequence of a lack of mining closure regulation, a large number of abandon small-to-medium size metal-contaminated sites have been identified in the last survey performed by the Chilean Government. Therefore, more research development on sustainable reclamation technologies must be made in this extreme arid-dry zone. The objective of this study is to test the effectiveness of soil remediation by washing contaminated soil using camellian-derived saponin for the mobilization of copper. Soil samples were taken from an abandoned copper mine site located at 30 km North Antofagasta city. They were dried and sieved at 75 µm for physico-chemical characterization. A commercial saponin extracted from camellias seed was used as biosurfactant. The soil used contains 67.4 % sand, 26.3 % silt and 6.3 % clay. The soil is highly saline (electric conductivity, 61 mScm-1), with low organic matter content (0.41%), with pH 7.30, and a high copper concentration (2200 mg Kg-1 soil). According to the sequential extraction procedure of the whole soil, copper species are mainly as exchangeable fraction (608.2 mg Kg-1 soil) and reducible fraction (787.3 mg Kg-1 soil), whereas the oxidizable and residual fractions are around 205.7 and 598.8 mg Kg-1 soil, respectively. Soil particles under 75 µm contain higher copper concentrations (1242 mg Kg-1 soil) than the particle fraction over 75 µm (912 mg Kg-1 soil). All washing assays were conducted in triplicate using a standard batch technique with and without pH adjustment. The testing protocols includes evaluation of four solid to liquid ratio (0.5:50; 1.0:50; 2.0:50, and 5.0:50) and three saponin concentrations (0, 1, and 4 mg L-1). After shaking (24 h, 20±1 °C) and subsequently filtration (0.45 µm), the supernatants were analyzed for copper and pH. The removal efficiencies of copper by saponin solutions were calculated in according to the

Landscape evolution and origin of Lake Fúquene (Colombia): Tectonics, erosion and sedimentation processes during the Pleistocene

NARCIS (Netherlands)

Sarmiento, G.; Gaviria, S.; Hooghiemstra, H.; Berrio, J.C.; van der Hammen, T.

2008-01-01

The Basin of Ubaté-Chichinquirá (5°28′N, 73°45′ W, c. 2580 m altitude) includes the Fúquene Valley and is located in the central part of the Eastern Cordillera of Colombia. Rocks and sediments were folded and faulted during the Miocene, uplifted during the (late) Pliocene, and affected by glaciers

Vegetation types on Mount Akiki, Northern Luzon, Philippines

NARCIS (Netherlands)

Bout, I.E.

2002-01-01

Mount Akiki (16° 37’ N, 120° 53’ E, c. 2760 m alt.) is one of the highest mountain peaks in the Cordillera mountain range, Luzon Island, Philippines. It is situated in the municipality of Benguet, north-east of Baguio City (a world famous tourist city in the region) and is north-west of Mt Pulog,

BOMBACACEAE NEOTROPICAE NOVAE VEL MINUS COGNITAE VII. REDESCUBRIMIENTO DE PACHIRA PULCHRA PLANCH. & LIND. EX TRIANA & PLANCH

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FERNÁNDEZ-ALONSO JOSÉ LUIS

2003-06-01

Full Text Available Se aclara la identidad de Pachira pulchra, especie poco conocida descrita del nortede la Cordillera Oriental de Colombia y se complementa su descripción al darse aconocer sus frutos y semillas. Se incluye una clave para el grupo de especiesandinas del género Pachira, relacionadas con la que se comenta en este trabajo.

Advances in the knowledge of the mining geological anomaly uraniferous Medano Rico, Disc. Jachal, San Juan Province

International Nuclear Information System (INIS)

Matar, M.; Arroqui, A.; Wetten, A.; Banchig, P.; Iglesias, R.

2010-01-01

Preliminary results of research carried out in the area of ​​Medano Rico, Dto Jachal San Juan Province, under the project Implementation of a model for exploration of uranium in Pre cordillera describes this work. The research tasks are intended to deepen the knowledge of the area to establish a genetic model of uranium anomaly

Espacios cohabitados: Proposiciones sobre la ambigüedad espacial de Valparaíso

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Claudio Astudillo

2011-12-01

El siguiente artículo intenta explicar la incidencia que tiene la autoconstrucción de la vivienda en las diversas relaciones cotidianas de la ciudad que llegan a constituir nuevas formas de cohabitación ambiguas pero complejas, basándose en los resultados de una investigación experiencial en el Cerro Cordillera titulada "la casa inacabada".

El mundo del libro: Enero de 1967

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Agustín Rodríguez Garavito

1967-01-01

Full Text Available Se presentan las reseñas de las siguientes obras y autores: -Escritos de dos economistas coloniales. De Narváez, Antonio -La cordillera de Bogotá. Hettner, Alfred -La restauración constitucional. E. Acosta, Pablo -Canciones para asumir tu vuelo. Bonilla-Naar, Alfonso -Colombia historia y estampas. Paredes Pardo y Nereo, Jaime.

Geology of quadrangles H-12, H-13, and parts of I-12 and I-13, (zone III) in northeastern Santander Department, Colombia

Science.gov (United States)

Ward, Dwight Edward; Goldsmith, Richard; Cruz, Jaime B.; Restrepo, Hernan A.

1974-01-01

A program of geologic mapping and mineral investigation in Colombia was undertaken cooperatively by the Colombian Instituto Nacional de Investigaciones Geologico-Mineras (formerly known as the Inventario Minero Nacional), and the U. S. Geological Survey; by the Government of Colombia and the Agency for International Development, U. S. Department of State. The purpose was to study, and evaluate mineral resources (excluding of petroleum, coal, emeralds, and alluvial gold) of four selected areas, designated Zones I to IV, that total about 70,000 km2. The work in Zone III, in the Cordillera Oriental, was done from 1965 to 1968. The northeast trend of the Cordillera Oriental of Colombia swings abruptly to north-northwest in the area of this report, and divides around the southern end of the Maracaibo Basin. This section of the Cordillera Oriental is referred to as the Santander Massif. Radiometric age determinations indicate that the oldest rocks of the Santander massif are Precambrian and include high-grade gneiss, schist, and migmatite of the Bucaramanga Formation. These rocks were probably part of the Precambrian Guayana Shield. Low- to medium-grade metamorphic rocks of late Precambrian to Ordovician age .include phyllite, schist, metasiltstone, metasandstone, and marble of the Silgara Formation, a geosynclinal series of considerable extent in the Cordillera Oriental and possibly the Cordillera de Merida of Venezuela. Orthogneiss ranging from granite to tonalite is widely distributed in the high- and medium-grade metamorphic rocks of the central core of the massif and probably represents rocks of two ages, Precambrian and Ordovician to Early Devonian. Younger orthogneiss and the Silgara are overlain by Middle Devonian beds of the Floresta Formation which show a generally low but varying degree of metamorphism. Phyllite and argillite are common, and infrequent marble and other calcareous beds are fossiliferous. Except for recrystallization in limestones of !the

The illitization of dickite: chemical and structural evolution of illite from diagenetic to metamorphic conditions

Czech Academy of Sciences Publication Activity Database

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

2009-01-01

Roč. 21, č. 2 (2009), s. 361-372 ISSN 0935-1221 Grant - others:Ministerio de Educacion y Ciencia (ES) CGL 2006-02481; Ministerio de Educacion y Ciencia (ES) RNM-199 Institutional research plan: CEZ:AV0Z30130516 Keywords : Betic-Rif Cordillera * anchizone * dickite * illite * Na-K white mica * TEM/AEM Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.450, year: 2009

Agate and Amethyst Project. Detailed Exploration of amethyst deposits. Gemological District Los Catalanes - Artigas, Uruguay

International Nuclear Information System (INIS)

Techera, J.

2011-01-01

The objective of this project is to achieve the knowledge of the amethyst geodes deposits filled with hard rock. For this purpose have studied two sites located in pilot mine Santino and pilot mine La Cordillera in the Gemoligical district Los Catalnes in Artigas town. The importance of this mineral riches is the base of mining projects that generate jobs and services.

San Pedro de la Paz: elementos del patrimonio natural estructurantes del paisaje urbano, seccional El Venado

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Leonel Pérez Bustamante

2003-09-01

Full Text Available El proyecto Plan Seccional El Venado se circunscribe en la intención de desarrollar un proyecto inmobiliario de gran extensión territorial en las mesetas de la Cordillera de Nahuelbuta, comuna de San Pedro de la Paz, en el denominado fundo El Venado.

Geomorphological aspects of the Pisuerga drainage area in the Cantabrian mountains (Spain)

NARCIS (Netherlands)

Nossin, J.J.

1959-01-01

Capítulo 1. Introducción Se han ejecutado investigaciones geomorfológicas en la parte meridional de la Cordillera Cantábrica (dib. 1), en el terreno drenado por el tramo superior del Río Pisuerga, por el Río Camesa, afluente del mismo, y por el Río Rubagón, afluente del Río Camesa. Se encuentra la

Parasites of the flatfish Paralichthys adspersus (Steindachner, 1867 (Pleuronectiformes from northern Chile

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Marcelo E Oliva

1996-06-01

Full Text Available Three species of protistan and 22 species of metazoan parasites were obtained from a sample of 179 flatfish, (Paralichthys adspersus taken-off Antofagasta, northern Chile. Prevalence of infection of seven parasites (Protista: 1, Copepoda: 2, Digenea: 1, Acantocephala: 1, Nematoda: 2 was significantly and positively correlated with host size. Host's sex do not seem to affect prevalence of infection, except for Nybelinia surmenicola, Capillaria sp. and Anisakis sp. (prevalence of infection significantly greater in males than females and Philometra sp. (prevalence higher in females. Mean abundance is correlated with size in nine species (Protista: 1, Copepoda: 2, Digenea: 3, Acantocephala: 1, Nematoda: 2. Host's sex do not affect mean abundance, except for Cainocreadium sp. and Philometra sp.(mean abundance higher in females and Nybelinia surmenicola, Capillaria sp. and Anisakis sp. (mean abundance higher in males.

Biostratigraphy of the upper Bajocian-middle Callovian (Middle Jurassic), South America

Science.gov (United States)

Riccardi, A. C.; Westermann, G. E. G.; Elmi, S.

The biostratigraphic division of the upper Bajocian-middle Callovian of South America is based on ammonites from different sections of the following provinces and regions: Neuquén, Mendoza, and San Juan in Argentina; Malleco, Linares, Talca, Atacama, Antofagasta, and Tarapacá in Chile. The complete upper Bajocian-middle Callovian succession includes the following biostratigraphic units: the Megasphaeroceras magnum assemblage zone, lowermost upper Bajocian; the Cadomites-Tulitidae mixed assemblages, (?lower) middle and upper Bathonian; the Steinmanni zone, index Lilloettia steinmanni (Spath), uppermost Bathonian, with two local horizons— Stenocephalites gerthi horizon (Argentina) and Choffatia jupiter horizon (northern Chile); the Vergarensis zone, index Eurycephalites vergarensis (Burck.), near the Bathonian-Callovian boundary; the Bodenbenderi zone, index Neuqueniceras (Frickites) bodenbenderi (Tornq.), lower Callovian; the Proximum zone, index Hecticoceras proximum Elmi, uppermost lower Callovian; and the Rehmannia (Loczyceras) patagoniensis horizon, middle Callovian.

Discursos sobre normas relativas a sexualidad en jóvenes del norte de Chile

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Jimena Silva-Segovia

2015-01-01

Full Text Available Resumen: Esta investigación tuvo por objetivo conocer los discursos institucionales de la sexualidad y el autocuidado juvenil. Los participantes fueron hombres y mujeres jóvenes de entre 15 y 19 años, pertenecientes a establecimientos educativos públicos, privados y universitarios de la ciudad de Antofagasta, en el norte de Chile. Se trabajó con una metodología cualitativa, aplicando entrevistas en profundidad a 24 sujetos. Los principales hallazgos sugieren una relación flexible del sujeto joven con las normativas institucionales, en algunos casos adscribiéndose a sus mandatos y, en otros, ejerciendo disidencias. Asimismo, se advirtió una implementación deficiente de programas en educación sexual, constituyendo una problemática transversal en establecimientos privados y públicos, aunque con mayores repercusiones sociales en estos últimos.

Leaching of copper concentrates using NaCl and soluble copper contributed by the own concentrate; Lixiviacion de concentrados de cobre utilizando NaCl y el cobre soluble aportado por el propio concentrado

Energy Technology Data Exchange (ETDEWEB)

Herrero, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Vinals, J.

2005-07-01

Leaching of copper concentrates using cupric chloro complexes, generated in situ by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variable such as a chloride concentration, soluble copper concentration, leaching time, solid percentage and temperature were studied. DRX and EDS analyzed some of the residues. the experimental results indicated that it is possible to obtain solutions having high copper content (15 to 35 g/L) and 2 to 5 g/L free acid in order to submit this solution directly to a solvent extraction stage. The leaching tests use common reactive and low cost such as sodium chloride and sulfuric acid. (Author) 16 refs.

Leaching of copper concentrates using NaCl and soluble copper contributed by the own concentrate

International Nuclear Information System (INIS)

Herrero, O.; Bernal, N.; Quiroz, R.; Fuentes, G.; Vinals, J.

2005-01-01

Leaching of copper concentrates using cupric chloro complexes, generated in situ by the reaction between Cu(II), aported by the soluble copper content of the concentrate, and sodium chloride in acid media was studied. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Chemical and mineralogical characterization from original concentrates was made. Typical variable such as a chloride concentration, soluble copper concentration, leaching time, solid percentage and temperature were studied. DRX and EDS analyzed some of the residues. the experimental results indicated that it is possible to obtain solutions having high copper content (15 to 35 g/L) and 2 to 5 g/L free acid in order to submit this solution directly to a solvent extraction stage. The leaching tests use common reactive and low cost such as sodium chloride and sulfuric acid. (Author) 16 refs

Amino acid biogeo- and stereochemistry in coastal Chilean sediments

DEFF Research Database (Denmark)

Lomstein, Bente Aagaard; Jørgensen, Bo Barker; Schubert, Carsten J.

2006-01-01

The spatial distribution of total hydrolysable amino acids (THAA) and amino acid enantiomers (D- and L-forms) was investigated in sediments underlying two contrasting Chilean upwelling regions,: at ~23°S off Antofagasta and at ~36°S off Concepcion. The contribution of amino acids to total organic...... carbon (%TAAC: 7-14%) and total nitrogen (%TAAN: 23-38%) in surface sediments decreased with increasing water depth (from 126 to 1350 m) indicating that organic matter becomes increasingly decomposed in surface sediments at greater water depth. Changes in the ratio between the protein amino acid...... aspartate and its non-protein degradation product β-alanine confirmed this observation. Furthermore, estimates of THAA mineralization showed that sedimentary amino acid reactivity decreased with both increasing water depth as well as progressive degradation status of the organic matter that was incorporated...

Petrology of the Miocene igneous rocks in the Altar region, main Cordillera of San Juan, Argentina. A geodynamic model within the context of the Andean flat-slab segment and metallogenesis

Science.gov (United States)

Maydagán, Laura; Franchini, Marta; Chiaradia, Massimo; Pons, Josefina; Impiccini, Agnes; Toohey, Jeff; Rey, Roger

2011-07-01

The Altar porphyry Cu-(Au-Mo) deposit (31° 29' S, 70° 28' W) is located in the Andean Main Cordillera of San Juan Province (Argentina), in the southern portion of the flat-slab segment (28-33°S), 25 km north of the world-class porphyry Cu-Mo deposits of Los Pelambres and El Pachón. Igneous rocks in the area have been grouped into the Early Miocene Lower Volcanic Complex -composed of intercalations of lava flows and thin volcaniclastic units that grade upwards to a thick massive tuff- and the Middle-Late Miocene Upper Subvolcanic Suite that consists of a series of porphyritic stocks and dikes and magmatic and hydrothermal breccias. The Lower Volcanic Complex represents an Early Miocene arc (20.8 Ma ± 0.3 Ma; U-Pb age) erupted over a steep subduction zone. Their magmas equilibrated with an assemblage consisting of plagioclase- and pyroxene-dominated mineral residues, and experienced fractional crystallization and crustal contamination procesess. Their radiogenic signatures are interpreted to indicate conditions of relatively thickened continental crust in Altar during the Early Miocene, compared to the south and west. The Upper Subvolcanic Suite represents the development of a Middle-Late Miocene arc (11.75 ± 0.24 Ma, 10.35 ± 0.32 Ma; U-Pb ages) emplaced over a shallow subduction zone. A magmatic gap in Altar area betwen the Lower Volcanic Complex and Upper Subvolcanic Suite correlates with documented higher rates of compression in this period, that may have favored the storage of the USS magmas in cameras within the crust. Magmas of the Upper Subvolcanic Suite require a hornblende-bearing residual mineral assemblage that is interpreted to reflect their higher water contents. The relatively uniform radiogenic isotope compositions of the Upper Subvolcanic Suite magmas suggest a homogeneously mixed crust-mantle contribution in the source region. They have similar REE signatures as other fertile intrusives of the flat-slab. The differences observed in their

Climbing in the high volcanoes of central Mexico

Science.gov (United States)

Secor, R. J.

1984-01-01

A chain of volcanoes extends across central Mexico along the 19th parallel, a line just south of Mexico City. The westernmost of these peaks is Nevado de Colima at 4,636 feet above sea level. A subsidiary summit of Nevado de Colima is Volcan de Colima, locally called Fuego (fire) it still emits sulphurous fumes and an occasional plume of smoke since its disastrous eruption in 1941. Parictuin, now dormant, was born in the fall of 1943 when a cornfield suddenly erupted. Within 18 months, the cone grew more than 1,700 feet. Nevado de Toluca is a 15,433-foot volcanic peak south of the city of Toluca. Just southeast of Mexico City are two high volcanoes that are permanently covered by snow: Iztaccihuatl (17,342 fet) and Popocatepetl (17,887 feet) Further east is the third highest mountain in North America: 18,700-foot Citlateptl, or El Pico de Orizaba. North of these high peaks are two volcanoes, 14, 436-foot La Malinche and Cofre de Perote at 14,048 feet. This range of mountains is known variously as the Cordillera de Anahuac, the Sierra Volcanica Transversal, or the Cordillera Neovolcanica. 

Molecular identification of vectors of Leishmania in Colombia: mitochondrial introgression in the Lutzomyia townsendi series.

Science.gov (United States)

Testa, J M; Montoya-Lerma, J; Cadena, H; Oviedo, M; Ready, P D

2002-12-01

The identity of the sandfly vectors of Leishmania braziliensis in Valle del Cauca Department, Colombia, was originally given as Lutzomyia townsendi, but then changed to L. youngi, another member of the L. townsendi series (Verrucarum group) with isomorphic females. To identify members of this series in Valle del Cauca, we analyzed the nuclear gene elongation factor-alpha (EF-alpha) and the mitochondrial gene cytochrome b (Cyt b). DNA sequences from the L. verrucarum series (L. columbiana, L. evansi and L. ovallesi) were used as outgroups. Flies from two locations on the western cordillera of the Andes were identified as L. townsendi s.s., according to male morphology and distinctive gene lineages. In the third location, on the central cordillera of the Andes, most specimens were identified as belonging to a geographical population of L. youngi, according to male morphology, an EF-alpha lineage shared with L. youngi from the Venezuelan-type locality, and a distinctive Cyt b sub-lineage. All other specimens were identified as L. youngi with the introgressed Cyt b sequences of L. townsendi. Such interspecific introgression implies that vectorial traits and ecological associations may no longer be viewed as fixed properties of different morphospecies.

Paleontología y ambientes sedimentarios del Triásico medio, Muschelkalk, de la Cordillera Ibérica 1: Cuencas y Valencia. España

Directory of Open Access Journals (Sweden)

López Gómez, J.

1989-12-01

, constituyen la Facies Muscbelkalk al SE. de la Rama Castel1ana de la Cordil1era Ibérica. Este trabajo enfoca el estudio paleontológico y de los medios sedimentarios de las dos unidades carbonatadas (d.L. y d.c.C.. Para ello, se han utilizado 10 columnas estratigráficas a lo largo de todo el área de estudio en las cuales se han diferenciado 9 asociaciones de facies constituidas cada una por una secuencia característica de menos de 2 m. de espesor. Se ha escogido una serie tipo en la que se han diferenciado 9 tramos constituidos cada uno de el10s por la repetición de una misma secuencia de las anteriormente citadas. Del análisis de estas secuencias han sido diferenciados tres distintos subambientes para cada unidad carbonatada, siendo éstos de bajio, zona protegida poco profunda y zona supramareal «shoal», «lagoon» y «Sabkba», respectivamente dentro de una rampa somera, y dos episodios en el desarrollo del sistema deposicional, uno primero y corto transgresivo y otro segundo y mayor de carácter regresivo. Posiblemente debido a los efectos de la dolomitización, el registro fósil es en general escaso y mal conservado. El mayor contenido está constituido por moluscos de la clase Bivalvia que refleja una asociación bentónica principalmente compuesta por suspensívoros. Aunque los bivalvos son encontrados en ambas unidades carbonatadas, en la superior (d.c.C., la diversidad específica es mayor. El análisis tafonómico realizado nos permite identificar algunas asociaciones autóctonas, formadas principalmente por elementos acumulados en ambas unidades. Se define cuantitativamente la «Fauna de Teruel», como el conjunto de bivalvos característicos de las capas terminales del Muscbelkalk carbonatado más alto de la Cordillera Ibérica; para esta definición, nos basamos principalmente en los bal1azgos de las series de Villora y Henarejos. El conjunto de bivalvos está formado mayoritariamente por infaunales, seguido de endo y epibisados con una

New stratigraphic, chronologic, and magnetic fabric constraints for Neogene and Quaternary ignimbrites in the Central Andes (South Peru)

Science.gov (United States)

De La Rupelle, A.; Thouret, J. C.; Cubukcu, H. E.; Jicha, B.; Bréard, E.; Gerbe, M.-C.; Le Pennec, J.-L.; Diot, H.; Boivin, P.

2012-04-01

Central Andean deformation history in southern Peru is recorded in Neogene volcanic units of Ocoña and Cotahuasi canyons that cut across the western Cordillera. Acceleration (100 km3) Nazca (c.24.6 Ma), Alpabamba (19.4-18.0 Ma), and Huaylillas (14.25-12.7 Ma) ignimbrite sheets preceded the canyon incision, whereas sheets of smaller volume (Peru, stratigraphy, chronology, AMS, fabric, Neogene, Quaternary.

Indigenous Social Capital in Traditional Agro-Food Marketing Systems: The Role of Trust in Governance Structure Selection in the Philippine Highlands

OpenAIRE

Milagrosa, Aimee; Slangen, Louis H.G.

2006-01-01

The decision-making of indigenous Ibaloi and Kankanaey growers in seven highland communities of Benguet, Cordillera region Philippines was captured in three models. The models explain factors affecting their selection of primary transacting partners. The farmers three main primary marketing links are commissioners, wholesalers and contractors. Commissioner-led governance structures are market-based and the relationship is motivated by profit. Wholesaler-led governance structures are partly-ma...

An addition to the diversity of dendrobatid frogs in Venezuela: description of three new collared frogs (Anura: Dendrobatidae: Mannophryne

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César Luis Barrio-Amorós

2010-07-01

Full Text Available Three new species of collared frogs of the genus Mannophryne are described from Venezuela. Two are newly discovered taxa from the Venezuelan Andes, whereas the third species, previously confused with M. trinitatis, is from the Caracas area in the Cordillera de la Costa. The call of the three new species and that of Mannophryne collaris are described. Taxonomic, zoogeographic, and conservation issues are discussed.

Geometry of the neoproterozoic and paleozoic rift margin of western Laurentia: Implications for mineral deposit settings

Science.gov (United States)

Lund, K.

2008-01-01

The U.S. and Canadian Cordilleran miogeocline evolved during several phases of Cryogenian-Devonian intracontinental rifting that formed the western mangin of Laurentia. Recent field and dating studies across central Idaho and northern Nevada result in identification of two segments of the rift margin. Resulting interpretations of rift geometry in the northern U.S. Cordillera are compatible with interpretations of northwest- striking asymmetric extensional segments subdivided by northeast-striking transform and transfer segments. The new interpretation permits integration of miogeoclinal segments along the length of the western North American Cordillera. For the U.S. Cordillera, miogeoclinal segments include the St. Mary-Moyie transform, eastern Washington- eastern Idaho upper-plate margin, Snake River transfer, Nevada-Utah lower-plate margin, and Mina transfer. The rift is orthogonal to most older basement domains, but the location of the transform-transfer zones suggests control of them by basement domain boundaries. The zigzag geometry of reentrants and promontories along the rift is paralleled by salients and recesses in younger thrust belts and by segmentation of younger extensional domains. Likewise, transform transfer zones localized subsequent transcurrent structures and igneous activity. Sediment-hosted mineral deposits trace the same zigzag geometry along the margin. Sedimentary exhalative (sedex) Zn-Pb-Ag ??Au and barite mineral deposits formed in continental-slope rocks during the Late Devonian-Mississippian and to a lesser degree, during the Cambrian-Early Ordovician. Such deposits formed during episodes of renewed extension along miogeoclinal segments. Carbonate-hosted Mississippi Valley- type (MVT) Zn-Pb deposits formed in structurally reactivated continental shelf rocks during the Late Devonian-Mississippian and Mesozoic due to reactivation of preexisting structures. The distribution and abundance of sedex and MVT deposits are controlled by the

Constraints on deformation of the Southern Andes since the Cretaceous from anisotropy of magnetic susceptibility

Science.gov (United States)

Maffione, Marco; Hernandez-Moreno, Catalina; Ghiglione, Matias C.; Speranza, Fabio; van Hinsbergen, Douwe J. J.; Lodolo, Emanuele

2015-12-01

The southernmost segment of the Andean Cordillera underwent a complex deformation history characterized by alternation of contractional, extensional, and strike-slip tectonics. Key elements of southern Andean deformation that remain poorly constrained, include the origin of the orogenic bend known as the Patagonian Orocline (here renamed as Patagonian Arc), and the exhumation mechanism of an upper amphibolite facies metamorphic complex currently exposed in Cordillera Darwin. Here, we present results of anisotropy of magnetic susceptibility (AMS) from 22 sites in Upper Cretaceous to upper Eocene sedimentary rocks within the internal structural domain of the Magallanes fold-and-thrust belt in Tierra del Fuego (Argentina). AMS parameters from most sites reveal a weak tectonic overprint of the original magnetic fabric, which was likely acquired upon layer-parallel shortening soon after sedimentation. Magnetic lineation from 17 sites is interpreted to have formed during compressive tectonic phases associated to a continuous N-S contraction. Our data, combined with the existing AMS database from adjacent areas, show that the Early Cretaceous-late Oligocene tectonic phases in the Southern Andes yielded continuous contraction, variable from E-W in the Patagonian Andes to N-S in the Fuegian Andes, which defined a radial strain field. A direct implication is that the exhumation of the Cordillera Darwin metamorphic complex occurred under compressive, rather than extensional or strike-slip tectonics, as alternatively proposed. If we agree with recent works considering the curved Magallanes fold-and-thrust belt as a primary arc (i.e., no relative vertical-axis rotation of the limbs occurs during its formation), then other mechanisms different from oroclinal bending should be invoked to explain the documented radial strain field. We tentatively propose a kinematic model in which reactivation of variably oriented Jurassic faults at the South American continental margin controlled

Detrital Zircon Provenance Record of Pre-Andean to Modern Tectonics in the Northern Andes: Examples from Peru, Ecuador, and Colombia

Science.gov (United States)

George, S. W. M.; Jackson, L. J.; Horton, B. K.

2015-12-01

Detrital zircon U-Pb age distributions from modern rivers and Mesozoic-Cenozoic basin fill in the northern Andes provide insights into pre-Andean, Andean, and active uplift and exhumation of distinctive sediment source regions. Diagnostic age signatures enable straightforward discrimination of competing sediment sources within the Andean magmatic arc (Western Cordillera-Central Cordillera), retroarc fold-thrust belt (Eastern Cordillera-Subandean Zone), and Amazonian craton (composed of several basement provinces). More complex, however, are the mid/late Cenozoic provenance records generated by recycling of basin fill originally deposited during early/mid Mesozoic extension, late Mesozoic thermal subsidence, and early Cenozoic shortening. Although subject to time-transgressive trends, regionally significant provenance patterns in Peru, Ecuador, and Colombia reveal: (1) Triassic-Jurassic growth of extensional subbasins fed by local block uplifts (with commonly unimodal 300­-150 Ma age peaks); (2) Cretaceous deposition in an extensive postrift setting fed by principally cratonic sources (with common 1800-900 Ma ages); and (3) Cenozoic growth of a broad flexural basin fed initially fed by magmatic-arc rocks (100-0 Ma), then later dominance by thrust-belt sedimentary rocks with progressively greater degrees of basin recycling (yielding diverse and variable age populations from the aforementioned source regions). U-Pb results from modern rivers and smaller subbasins prove useful in evaluating source-to-sink relationships, downstream mixing relationships, hinterland-foreland basin connectivity, paleodrainage integration, and tectonic/paleotopographic reconstructions. Most but not all of the elevated intermontane basins in the modern hinterland of the northern Andes contain provenance records consistent with genesis in a broader foreland basin developed at low elevation. Downstream variations within modern axial rivers and Cenozoic axial basins inform predictive models of

Seismological observations at the Northern Andean region of Colombia: Evidence for a shallowly subducting Caribbean Slab and an extensional regime in the upper plate

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Monsalve, G.; Cardona, A.; Yarce, J.; Alvira, D.; Poveda, E.

2013-05-01

A number of seismological observations, among which we can mention teleseismic travel time residuals, P to S receiver functions and Pn velocity quantification, suggest a clear distinction between the seismic structure of the crust and uppermost mantle between the plains on the Caribbean coast of Colombia and the mountains at the Northern Andean region. Absolute and relative travel time residuals indicate the presence of a seismically fast material in the upper mantle beneath northern Colombia; preliminary results of Pn studies show a region of relatively slow Pn velocities (between 7.8 and 7.9 km/s) underneath the Caribbean coast, contrasting with values greater than 8 km/s beneath the Central and Western cordilleras of Colombia, and the Pacific coast; receiver functions suggest a significantly thinner crust beneath the Caribbean coast, with a crustal thickness between 25 and 30 km, than beneath the Northern Andean zone at the cordilleras of Colombia, where it exceeds 40 km and reaches about 57 km at the location of Bogota. Besides the obviuos discrepancies that appear in response to different topography, we think that the seismological observations are a consequence of the presence of two very distinct slab segments beneath Colombia and contrasting behaviors of the upper plate, which correspond to Caribbean and Nazca subductions. Our seismic observations can be explained by a shallowly subducting Caribbean Plate, in the absence of an asthenospheric wedge, that steepens at about the location of the Bucaramanga nest, and a thinned continental crust that reflects an extensional component linked to oblique convergence of the Caribbean, which contrasts with the crustal thickening in the Andean Cordillera linked to crustal shortening and Nazca plate subuction. These new data are consistent with the idea of of a relatively warm Nazca slab of Neogene age which seems to have a relatively frontal convergence, and a colder, more buoyant Caribbean slab which represents an

Síntesis biogeográfica y fitosociológica de la vegetación del Parque Natural de la Sierra de Baza (Cordillera Bética, Andalucía, Sur de España

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Olmedo-Cobo, José Antonio

2014-12-01

Full Text Available We present a synthesis of the vegetation of Natural Park of Sierra de Baza (Baetic mountain range, Andalusia, Southern Spain from a biogeographical and phytosociological approach integrated; the guidelines of the analysis are the series of vegetation and plant associations. We start of the literature review and field work to the syntaxonomical classification of different phytocoenoses identified, highlighting the status of this territory as enclave among various chorological sectors of Betic biogeographic province that have a clear influence on the configuration of different plant communities of Sierra de Baza. This has allowed the incorporation of new features and nuances of some phytosociological issues recently established, from the last biogeographical sectorization has been carried out for this territory.Se presenta una síntesis de la vegetación del Parque Natural de la Sierra de Baza (Cordillera Bética, Andalucía, Sur de España desde un enfoque biogeográfico y fitosociológico integrado, siendo las directrices del análisis las series de vegetación y las asociaciones vegetales. Se parte de la revisión bibliográfica y del trabajo de campo para la clasificación sintaxonómica de las distintas fitocenosis identificadas, resaltando la condición de este territorio como enclave situado entre varios sectores corológicos de la provincia biogeográfica Bética que tienen una clara influencia en la configuración de las diferentes comunidades vegetales de la Sierra de Baza. Todo ello ha permitido incorporar algunas novedades y matizaciones de ciertas cuestiones fitosociológicas establecidas recientemente, partiendo de la última sectorización biogeográfica que se ha llevado a cabo para este territorio. [fr] L’article pose une synthèse de la végétation du parc naturel de la Sierra de Baza (Cordillère Bétique Andalousie, Sud de l’Espagne à partir d’une approche biogéographique et phytosociologique intégrée; les

Preliminary Results From the CAUGHT Experiment: Investigation of the North Central Andes Subsurface Using Receiver Functions and Ambient Noise Tomography

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Ryan, J. C.; Ward, K. M.; Porter, R. C.; Beck, S. L.; Zandt, G.; Wagner, L. S.; Minaya, E.; Tavera, H.

2011-12-01

Jamie Ryan, Kevin M. Ward, Ryan Porter, Susan Beck, George Zandt, Lara Wagner, Estela Minaya, and Hernando Tavera The University of Arizona The University of North Carolina San Calixto Observatorio, La Paz, Bolivia IGP, Lima, Peru In order to investigate the interplay between crustal shortening, lithospheric removal, and surface uplift we have deployed 50 broadband seismometers in northwestern Bolivia and southern Peru as part of the interdisciplinary Central Andean Uplift and Geodynamics of High Topography (CAUGHT) project. The morphotectonic units of the central Andes from west to east, consist of the Western Cordillera, the active volcanic arc, the Altiplano, an internally drained basin (~4 km elevation), the Eastern Cordillera, the high peaks (~6 km elevation) of an older fold and thrust belt, the Subandean zone, the lower elevation active fold and thrust belt, and the foreland Beni basin. Between northwestern Bolivia and southern Peru, the Altiplano pinches out north of Lake Titicaca as the Andes narrow northward. The CAUGHT seismic instruments were deployed between 13° to 18° S latitudes to investigate the crust and mantle lithosphere of the central Andes in this transitional zone. In northwest Bolivia, perpendicular to the strike of the Andes, there is a total of 275 km of documented upper crustal shortening (15° to 17°S) (McQuarrie et al, 2008). Associated with the shortening is crustal thickening and possibly lithospheric removal as the thickening lithospheric root becomes unstable. An important first order study is to compare upper crustal shortening estimates with present day crustal thickness. To estimate crustal thickness, we have calculated receiver functions using an iterative deconvolution method and used common conversion point stacking along the same profile as the geologically based shortening estimates. In our preliminary results, we observed a strong P to S conversion corresponding to the Moho at approximately 60-65 km depth underneath the

Orientale and Caloris

Science.gov (United States)

McCauley, J.F.

1977-01-01

Applications of experimental explosion-crater data to Orientale and recent geologic mapping of the basin have produced a new stratigraphy and genetic model for Orientale that are also applicable to Caloris. The inner-basin scarp of Orientale is thought to be a bench separating the upper parts of the basin from its deep bowl-shaped interior. The elongated and complexly fractured domes of the basin floor formed by inward compression in the terminal stages of the cratering sequence. The Inner Montes Rook are considered a central peak ring. The Montes Rook and the nonlineated knobby and associated smoother materials that overlie the Cordillera scarp around much of its circumference are the uppermost parts of the overturned rim flap which formed early in the cratering event. The knobs and smaller massifs are probably coherent blocks quarried from deep within the moon. They were among the last materials to leave the basin and had little radial momentum unlike the lineated Hevelius which formed earlier by disaggregation of the rim flap, secondary cratering, and the ground surge. The Cordillera scarp, best seen on the east side of the basin but poorly developed and discontinuous on the west, is a primary feature formed early in the crater excavation process by basinward motions of the walls and the fractured zone beyond the rim of the expanding cavity. The Cordillera scarp is overlain by ejecta over most of its extent, and post-basin internal slumping, previously thought to be important, must be a subordinate process in development of the scarp. The basin fill in Caloris has no counterpart in Orientale but the materials between the most prominent scarp and the weakly developed outer scarp appear to be the degraded and possibly mantled equivalents of the massifs and knobs associated with the Montes Rook. The radially lineated terrain that generally lies beyond the outer scarp of Caloris is considered the subdued counterpart of the Hevelius Formation, which generally shows

FIBRAS ANIMALES ARQUEOLÓGICAS. ESTUDIO DE LA ESTRUCTURA FÍSICA CELULAR DE LAS FIBRAS/Archaeological animal fibres. Study of their physical cellular structure

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María del Carmen Reigadas

2012-11-01

Full Text Available El análisis microscópico de la morfología de fibras animales se ha empleado conjuntamente con otras líneas de evidencia, brindando información taxonómica útil para reconstruir posibles escenarios que den cuenta de las estrategias implementadas por las sociedades cazadoras- recolectoras y/ o productoras, en vistas a la explotación y aprovechamiento de los recursos animales. En esta oportunidad y en el marco de la vía mencionada, se presenta como complemento de los resultados obtenidos a partir de las variables cualitativas y cuantitativas tales como grosor, médula, tipo de fibra y color, el avance realizado en el estudio de la corteza, estructura no contemplada hasta el presente. Se evalúa a partir de la información generada su relevancia en la búsqueda de indicadores interespecíficos. El análisis fue realizado en muestras correspondientes al nivel 4 del sitio Cueva Salamanca 1 (7500 + 60 AP [Beta 178223] (Pintar 2004 y nivel 4 de Quebrada Seca 3 (Cal. 3684- 4226 1s (Aschero et al. 1993-94, ambos localizados en la puna meridional (Antofagasta de la Sierra, Argentina de las cuales ya se disponen designaciones taxonómicas obtenidas por análisis morfológico. Abstract Microscopic analysis of the morphology of animal fibers has been used in conjunction with other lines of evidence, providing useful taxonomic information to reconstruct scenarios that account for the strategies implemented by hunter-gatherers and producers, in view of the use of animal resources. Here, the advance made in the study of cortical cells is offered as a complement to results obtained from qualitative and quantitative variables such as thickness, medulla, fiber type and color. The information gained is used to evaluate the relevance in the search of interspecific indicators. The analysis was performed on samples corresponding to level 4 from Cueva Salamanca 1 (7500 ± 60 BP [Beta 178223] (Pintar 2004 and level 4 from Quebrada Seca 3 (Cal. 3684 to 4226 1s

Sustainability Assessment in Development Planning in Sub-National Territories: Regional Development Strategies in Chile

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Iván Franchi-Arzola

2018-05-01

Full Text Available In Chile, the increasing occurrence of socio-environmental conflicts demonstrates that Regional Development Strategies—Estrategia Regional de Desarrollo (ERD—as the main development policy of subnational territories (Regions, must consider sustainability as a central objective. The Taxonomy of Sustainability constitutes an assessment method that allows us to determine the correlation between the definitions of these public policies and the strategies for transition to sustainable development. The ERD of the Antofagasta and Aysén regions are the ones presenting the highest Taxonomic Index; this indicates a higher strategic content for the promotion of sustainability. It is also noted that the political will that conditions the principles and values on which the ERD are based is strongly determined by investment projects and socio-environmental conflicts, which represent the tension between environmental protection and the capacity and interests of regional society in the development project.

Crimen y exhibición de prostitutas en el norte de Chile: Producción y uso de las imágenes del cuerpo de mujeres asesinadas

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Lilith Kraushaar

2013-07-01

Full Text Available Las clasificaciones de ciertos cuerpos, específicamente aquí el de "la prostituta" en momentos históricos específicos, nos plantean interrogantes sobre los imaginarios y las significaciones que las constituyeron, y los mecanismos que se utilizaron para lograr la distinción de estos cuerpos prostitucionales. Desde estos cuestionamientos analizamos algunas imágenes mediáticas de dos casos policiales de mujeres asesinadas: "La mujer de botas negras" en Calama de 1969 y "la mujer fondeada" en Antofagasta de 1983, en el norte de Chile. Su exposición y debate evidenció la convergencia de discursos de sexualidad, violencia y deseo de las relaciones de género y clase en la figura de "la prostituta" y su posterior influencia en la resignificación de estas mujeres como santas populares en esas ciudades mineras.

IDEALES REGULATORIOS SOBRE EMBARAZO Y MATERNIDAD EN HOMBRES Y MUJERES JÓVENES DEL NORTE DE CHILE

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Jimena Silva Segovia

Full Text Available Resumen Este artículo se propone comprender los ideales regulatorios sobre embarazo y maternidad/paternidad en hombres y mujeres jóvenes, de enseñanza media de establecimientos privados y municipalizados de las ciudades de Antofagasta y Calama, Chile. Asimismo, se interpretan las construcciones subjetivas y sociales de acuerdo a dimensiones de género y nivel socioeconómico. La producción de información se llevó a cabo a través de entrevistas semiestructuradas y grupos de conversación. Los principales hallazgos sugieren cuatro ideales regulatorios que intervienen en la construcción de sujeto-joven: Idealesadultocéntricos, Ideales de Género, Ideales religiosos e Ideales familiares. Éstos intervienen de forma dinámica como soporte sociocultural regulatorio de las construcciones de sujeto-joven y sus discursos sobre el embarazo.

[Mental health and stress by acculturation in immigrants from South America in northern Chile].

Science.gov (United States)

Urzúa M, Alfonso; Heredia B, Osvaldo; Caqueo-Urízar, Alejandra

2016-05-01

Coping with changes brought about by immigration and social circumstances that often characterize this process may cause mental health problems. To analyze the relationship between acculturation stress and mental health symptoms in South American immigrants residing in Antofagasta, Chile. The OQ questionnaire, which assesses mental health and the acculturation stress questionnaire from Ruiz, were answered by 431 immigrants (53.8% Colombian and 46.2% Peruvian) aged between 18 and 65 years old. The major source of acculturation stress was distance from origin, followed by difficulties in social relationships and perceived discrimination and rejection. About 50% of respondents had elevated levels of discomfort in their life, with mental health problems derived from their adjustment to social roles and relationships. There was a high correlation between acculturation stress levels and severity of mental health symptoms. Immigrants are exposed to high levels of stress resulting in a negative impact on their mental health.

The influence of acculturation strategies in quality of life by immigrants in Northern Chile.

Science.gov (United States)

Urzúa, Alfonso; Ferrer, Rodrigo; Canales Gaete, Valentina; Núñez Aragón, Dominique; Ravanal Labraña, Ivanna; Tabilo Poblete, Bárbara

2017-03-01

To establish the influence of acculturation strategies on quality of life, henceforth QoL. Using a cross-sectional design, two questionnaires were applied, the WHOQoL-BREF from the World Health Organization and Basabe's acculturation strategies. The questionnaires were applied to 853 Colombian and Peruvian immigrants living in Northern Chilean cities of Arica, Antofagasta and Santiago de Chile. In the psychological and social domains, as well as in the overall assessment of QoL, the most beneficial strategies are those where customs are maintained from the homeland, where "integration" then "separation" are the most beneficial. On the contrary, when the strategy for maintaining homeland customs is low, the QoL tends to be lower. The strategy of "marginalized" is associated with a lower QoL. Acculturation strategies mildly or moderately affect the psychological and social domains of quality of life as well as the overall assessment of QoL.

Persistent Engagement in Colombia

Science.gov (United States)

2014-07-01

the southwest to the northeast, provide the elevation that affords much of the population reprieve from the tropical heat . The Cordillera Oriental...intensification of urban terrorism and guerrilla warfare in 2001 had the opposite of the intended effect. Rather than cowing the government and its supporters, it...theorists have stressed the need for insurgents to conduct conventional warfare in the latter stages of conflict. Only conventional military forces

Taxonomic new species of Espeletiopsis cuatrec and Espeletia Mutis ex humb and Bonpl. (Asteraceae, Heliantheae, Espeletiinae) from Colombia

International Nuclear Information System (INIS)

Diaz Piedrahita, Santiago; Rodriguez Cabeza, Betsy Viviana.

2010-01-01

Three new species of Espeletia Mutis ex Humb and Bonpl. and a new species of Espeletiopsis Cuatrec., all from the Cordillera Oriental of Colombia, are named, described and illustrated. These new taxa were recorded from northern Colombia, Guanenta Alto Rio Fonce Flora and Fauna Sanctuary in Santander and in the paramos of Rabanal in Raquira, Pisba National Natural Park in Socota and La Cortadera in Siachoque in Boyaca.

Mesozoic–Cenozoic Evolution of the Western Margin of South America: Case Study of the Peruvian Andes

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Laura Gonzalez

2013-06-01

Full Text Available Based on the structural style and physiographic criteria, the Central Andes of Peru can be divided into segments running parallel to the Pacific coast. The westernmost segment, the Coastal Belt, consists of a Late Jurassic–Cretaceous volcanic arc sequence that was accreted to the South American craton in Cretaceous times. The Mesozoic strata of the adjacent Western Cordillera represent an ENE-vergent fold-and-thrust belt that formed in Eocene times. Tight upright folds developed above a shallow detachment horizon in the West, while more open folds formed above a deeper detachment horizon towards the East and in the neighboring Central Highlands. A completely different style with steeply dipping reverse faults and open folds affecting the Neoproterozoic crystalline basement is typical for the Eastern Cordillera. The Subandean Zone is characterized by mainly NE-vergent imbricate thrusting which occurred in Neogene times. A quantitative estimate of the shortening of the orogen obtained from balanced cross-sections indicates a total shortening of 120–150 km (24%–27%. This shortening was coevel with the Neogene westward drift of South America, occurred at rates between 3 and 4.7 mm/year and was responsible for the high elevation of the Peruvian Andes.

Programa de repoblamiento comuna de Santiago: un programa de gestión urbana

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Mauricio Valenzuela Verdugo

2003-09-01

Full Text Available En cuanto a su situación geográfica y topográfica, la ciudad de Santiago se encuentra ubicada en un valle precordillerano de la Cordillera de Los Andes, a unos 100 kilómetros del Océano Pacífico; y se ha desarrollado en una cuenca hidrográfica de 60 kilómetros de largo en el sentido norte sur, y unos 40 kilómetros de ancho en el sentido oriente poniente. Su aspecto general es de una planicie con pendiente aproximada de un 1% en el sentido oriente poniente, y con una altura promedio en torno a los 500 metros sobre el nivel del mar. Esta cuenca se encuentra rodeada en todo su entorno por cordones montañosos de una altura promedio de 1.500 metros, con una apertura hacia la Cordillera de Los Andes (denominado Cajón del Maipo, y otras dos aperturas (una hacia el norte y la otra hacia el sur que no coinciden linealmente, lo que no permite una ventilación del valle en el sentido horizontal de sur a norte.

The volcanism of the western part of the Los Frailes Meseta (Bolivia): a representative example of the Andean volcanism since the Upper Oligocene; Le volcanisme de la bordure occidentale de la Meseta de Los Frailes (Bolivie): un jalon representatif du volcanisme andin depuis l`Oligocene superieur

Energy Technology Data Exchange (ETDEWEB)

Leroy, L. [Nancy-1 Univ., 54 (France); Jimenez, N.

1996-12-31

The Los Frailes Meseta (Bolivia) is one of the large tertiary ignimbritic fields of the inner volcanic arc from Central Andes (Central Volcanic Zone. CVZ), in contact zone between the Altiplano to the west and the Eastern Cordillera to the east. Field observations and mineralogical and geochemical studies (major and trace elements) lead to distinguish two types of volcanism in the western border to the Meseta. During the Middle Miocene and Pliocene, the volcanic activity can be subdivided into three pyroclastic emission cycles, the Larco, Coroma and Pliocene ignimbrites, the first two being separated by the Quechua 2 orogeny. All these ignimbrites are very similar and correspond to peraluminous rhyolites to rhyodacites. In the studies area, the Coroma cycle is the only one where an ignimbrite-less evolved resurgent dome association can be observed. Beside these ignimbrites, isolated small lava flows and domes overlay and/or intrude all the other formations. They are meta-aluminous lavas with a shoshonitic affinity. A quaternary age can be attributed to his second volcanism. These two volcanic types are well-known in the CVZ and are related to the different deformation stages, either compressional or extensional, which occur alternately in the Cordillera since 26 Ma. (authors). 61 refs., 12 figs., 3 tabs.

The volcanism of the western part of the Los Frailes Meseta (Bolivia): a representative example of the Andean volcanism since the Upper Oligocene

International Nuclear Information System (INIS)

Leroy, L.; Jimenez, N.

1996-01-01

The Los Frailes Meseta (Bolivia) is one of the large tertiary ignimbritic fields of the inner volcanic arc from Central Andes (Central Volcanic Zone. CVZ), in contact zone between the Altiplano to the west and the Eastern Cordillera to the east. Field observations and mineralogical and geochemical studies (major and trace elements) lead to distinguish two types of volcanism in the western border to the Meseta. During the Middle Miocene and Pliocene, the volcanic activity can be subdivided into three pyroclastic emission cycles, the Larco, Coroma and Pliocene ignimbrites, the first two being separated by the Quechua 2 orogeny. All these ignimbrites are very similar and correspond to peraluminous rhyolites to rhyodacites. In the studies area, the Coroma cycle is the only one where an ignimbrite-less evolved resurgent dome association can be observed. Beside these ignimbrites, isolated small lava flows and domes overlay and/or intrude all the other formations. They are meta-aluminous lavas with a shoshonitic affinity. A quaternary age can be attributed to his second volcanism. These two volcanic types are well-known in the CVZ and are related to the different deformation stages, either compressional or extensional, which occur alternately in the Cordillera since 26 Ma. (authors). 61 refs., 12 figs., 3 tabs

Metalogenia de las mineralizaciones filonianas Pb-Sb de «Leonor» y «Aragon» (Ateca, Zaragoza

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Benito García, R.

1988-08-01

Full Text Available The geological, geochemical and metallogenetic features of some Pb-Sb mineralizations, were studied in this paper. These ore deposits are located in thbe Ateca region (Zaragoza, Spain, in the west part of the Iberian Range.The parageneses include mainly heteromorphite, galena, sphalerite, boumonite and baryte. The geochemical analyses of the host rocks show the lack of anomalys of Pb, Zn, Cu and Ba. The hypothesis of an hydrothermal origin could be established for these mineralizations in relation with the permian calc-alkaline magmatism of the Iberian Range.En este trabajo se estudian los caracteres geológicos, geoquímicos y metalogénicos de algunas mineralizaciones Pb-Sb de la zona de Ateca (Zaragoza, en la Rama Occidental de la Cordillera Ibérica.La paragénesis incluye heteromorfita, galena, esfalerita, boumonita y baritina, principalmente. Los análisis geoquímicos de las rocas encajantes revelan la inexistencia de anomalías en elementos metalogénicos en las mismas. Por último, podría establecerse la hipótesis de un origen hidrotermal de la mineralización relacionado con el magmatismo calcoalcalino de edad pérmica de la Cordillera Ibérica.

La red de monitoreo glacio-hidrologico de ORSTOM y de sus contrapartes en Bolivia, Peru y Ecuador : une herramienta para el estudio del recalentamiento global y de sus consecuencias en los tropicos

OpenAIRE

Pouyaud, Bernard; Francou, Bernard; Ribstein, Pierre

1995-01-01

Desde hace algunos años, junto con sus contrapartes sudamericanas de Bolivia, Peru y Ecuador, ORSTOM mantiene una red de mediciones en algunos glaciares representativos de estos 3 paises. Los glaciares tropicales son, en efecto, objetos hidrologicos que integran particularmente bien los efectos de un cambio climatico. Es asi que los primeros resultados evidenciaron la influencia de los acontecimientos ENSO sobre la hidrologia glaciar, con efectos contrastados en la Cordillera Real de Bolivia ...

Patterns in the distribution of vegetation in paramo areas: heterogeneity and spacial dependence

OpenAIRE

Arellano-P., Henry; Rangel-CH, J. Orlando

2012-01-01

Two methods of exploratory spatial data analysis (ESDA), analysis of spatial heterogeneity and dependence (auto-correlation), - - were applied to the cover patterns from ten paramo localities in the Central and Eastern cordilleras of Colombia. Among the localities studied, the high montane region of the Serrania de Perija, the paramo region of the Los Nevados National Park, and the paramo region under management of CORPOGUAVIO showed a good state of conservation and satisfactory level of conn...

Birds, Lower Sangay National Park, Morona-Santiago, Ecuador

OpenAIRE

Guevara, E.; Santander, T.; Guevara, J. E.; Gualotuña, R.; Ortiz, V.

2010-01-01

Sangay National Park is located at the mid-eastern Andean foothills of the Cordillera Oriental of Ecuador. We present a preliminary avifauna inventory corresponding to the lower zone of the Sangay National Park (SNP). One-hundred and twenty-seven bird species belonging to 39 families were recorded, including noteworthy records that represent range extensions for four species, Phaetornis hispidus (Gould 1846) (White-bearded Hermit), Ramphastos ambiguus Swainson 1823 (Black-mandibled Toucan), P...

Identifying the origin of underground water in the Andean Cordillera

International Nuclear Information System (INIS)

Rodriguez, C.O.

1979-01-01

Two problems associated with groundwater flow were fully identified by the application of geochemical techniques. The first was related to the Palacio tunnel, where infiltration of 400 litres/min caused caving-in and other problems which held up construction for several months. To anticipate further problems and to plan the requisite engineering work, a study was carried out to locate the origin of the groundwater responsible for these difficulties. Water samples were taken from the four possible sources: a pool, a series of large fissures, superficial fluvioglacial deposits and the Guadalupe sandstone which crops out one kilometre from the cave-in site. After correlation of the results of chemical analyses with geological and hydrological information about the area, the conclusion was reached that the groundwater in question flows from the Guadalupe sandstone through fractures and secondary openings. The second problem studied was that of the immense Quebradablanca landslide caused by infiltration of water into and percolation through alluvial deposits. A drainage system had already been designed to intercept and collect direct infiltration water above the alluvium, thereby preventing the latter from becoming saturated. The present study was carried out to determine whether there was groundwater flow from the rocks adjacent to the alluvium. The results of the geochemical analysis indicate that most of the water does in fact come from the adjacent hard rock rather than from direct infiltration of rain-water above the alluvium. This shows that the drainage system designed is insufficient for preventing saturation of the rock and that a more extensive and costly system would be needed to control the groundwater flow. (author)

La formación Capas Rojas: caracterización y génesis

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Molina, J. M.

1999-04-01

Full Text Available The characteristics (lithofacies, biofacies, age, thickness, vertical and lateral relations, etc., and significance of the Capas Rojas Formation (Upper Cretaceous-Eocene are analysed. This formation crops out widely in the Subbetic (External Zones of the Betic Cordillera. The Capas Rojas Formation presents a great uniformity in the wide sectors of this cordillera and has its equivalent in facies and age, in the Scaglia Rossa Formation of the Apennines and southern Alps and also in equally analogous formations in other Alpine Mediterranean domains. From the available sedimentological and paleoecological data, mainly from the macrofossils (isolated rudists and echinoids content and from the ichnofacies analysis, it is concluded that its deposition took place in a hemipelagic marine environment with a moderate depth (a few hundreds of metres during a long interval of time (40-50 Ma with a very low sedimentation rate (a few millimetres per thousand years. From the analysis of the evolution of the continental margin in which was deposited, and of their equivalents in other Alpine domains, is deduced that the beginning of its deposition recorded the end of the differentiation in troughs and swells of these passive margins in the advanced stages of the rifting, so that this unit, in wide sector of the basin covered areas with an irregular topography in the bottom, mainly controlled by faults and slowly leveled them.Se analizan las características (litofacies, biofacies, edad, potencia, etc. de la Formación Capas Rojas (Cretácico superior-Eoceno que aflora extensamente en el Subbético, dentro de las Zonas Externas de la Cordillera Bética. Esta formación presenta una gran uniformidad de facies en amplios sectores de la cordillera y tiene su equivalente, en facies y en edad, en la Formación Scaglia Rossa de los Apeninos del centro de Italia y de los Alpes meridionales y en formaciones igualmente análogas en otros dominios alpinos mediterráneos. A

Geodynamic controls on the contamination of Cenozoic arc magmas in the southern Central Andes: Insights from the O and Hf isotopic composition of zircon

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Jones, Rosemary E.; Kirstein, Linda A.; Kasemann, Simone A.; Dhuime, Bruno; Elliott, Tim; Litvak, Vanesa D.; Alonso, Ricardo; Hinton, Richard

2015-09-01

Subduction zones, such as the Andean convergent margin of South America, are sites of active continental growth and crustal recycling. The composition of arc magmas, and therefore new continental crust, reflects variable contributions from mantle, crustal and subducted reservoirs. Temporal (Ma) and spatial (km) variations in these contributions to southern Central Andean arc magmas are investigated in relation to the changing plate geometry and geodynamic setting of the southern Central Andes (28-32° S) during the Cenozoic. The in-situ analysis of O and Hf isotopes in zircon, from both intrusive (granitoids) and extrusive (basaltic andesites to rhyolites) Late Cretaceous - Late Miocene arc magmatic rocks, combined with high resolution U-Pb dating, demonstrates distinct across-arc variations. Mantle-like δ18O(zircon) values (+5.4‰ to +5.7‰ (±0.4 (2σ))) and juvenile initial εHf(zircon) values (+8.3 (±0.8 (2σ)) to +10.0 (±0.9 (2σ))), combined with a lack of zircon inheritance suggests that the Late Cretaceous (∼73 Ma) to Eocene (∼39 Ma) granitoids emplaced in the Principal Cordillera of Chile formed from mantle-derived melts with very limited interaction with continental crustal material, therefore representing a sustained period of upper crustal growth. Late Eocene (∼36 Ma) to Early Miocene (∼17 Ma) volcanic arc rocks present in the Frontal Cordillera have 'mantle-like' δ18O(zircon) values (+4.8‰ (±0.2 (2σ) to +5.8‰ (±0.5 (2σ))), but less radiogenic initial εHf(zircon) values (+1.0 (±1.1 (2σ)) to +4.0 (±0.6 (2σ))) providing evidence for mixing of mantle-derived melts with the Late Paleozoic - Early Mesozoic basement (up to ∼20%). The assimilation of both Late Paleozoic - Early Mesozoic Andean crust and a Grenville-aged basement is required to produce the higher than 'mantle-like' δ18O(zircon) values (+5.5‰ (±0.6 (2σ) to +7.2‰ (±0.4 (2σ))) and unradiogenic, initial εHf(zircon) values (-3.9 (±1.0 (2σ)) to +1.6 (±4.4 (2�

Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile)

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Bahlburg, H.; Breitkreuz, C.

The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin

Main natural hazards and vulnerability studies for some historical constructions and urban sectors of Valparaiso City (Chile)

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Romanelli, F.

2009-04-01

The Project "MAR VASTO" ("Risk Management in Valparaíso/Manejo de Riesgos en Valparaíso, Servicios Técnicos", 2007) started in March 2007, with coordination of ENEA (Italian Agency for New Technologies, Energy and Environment), participation of several partners (Italy: University of Ferrara, Faculties of Architecture and Engineering; University of Padua, Faculty of Engineering; Abdus Salam International Centre for Theoretical Physics of Trieste; Chile: Valparaíso Technical University Federico Santa Maria, Civil Works Department; Santiago University of Chile, Division Structures Constructions Geotechnics), and support of local stakeholders. Being Valparaíso included since 2003 in the UNESCO Word Heritage List of protected sites, the project main goals are the following: to collect, analyze and elaborate the existing information, with a satisfying evaluation of main hazards; to develop a GIS digital archive, well organized, user-friendly and easy to be implemented in the future, providing maps and scenarios of specific and multiple risk; to provide a vulnerability analysis for three historical churches (San Francisco del Baron, Las Hermanitas de la Providencia, La Matríz, made by various materials - masonry, concrete, wood and adobe - and located in different city sites) and for a building stock in the Cerro Cordillera (partially inside the UNESCO area), analyzing more than 200 constructions; to suggest guidelines for future urban planning and strengthening interventions. In the framework of the MAR VASTO Project, the most important hazards have been investigated carried out. With regard to seismic hazard, "state-of-the-art" information has been provided by Chilean partners and stakeholders, using materials of several studies and stored in original earthquake reports, local newspapers and magazines. The activities performed by the Italian team regarded the definition, for the city of Valparaiso, of earthquake scenarios and maps based on the neo

A study of SO2 emissions and ground surface displacements at Lastarria volcano, Antofagasta Region, Northern Chile

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Krewcun, Lucie G.

Lastarria volcano (Chile) is located at the North-West margin of the 'Lazufre' ground inflation signal (37x45 km2), constantly uplifting at a rate of ˜2.5 cm/year since 1996 (Pritchard and Simons 2002; Froger et al. 2007). The Lastarria volcano has the double interest to be superimposed on a second, smaller-scale inflation signal and to be the only degassing area of the Lazufre signal. In this project, we compared daily SO2 burdens recorded by AURA's OMI mission for 2005-2010 with Ground Surface Displacements (GSD) calculated from the Advanced Synthetic Aperture Radar (ASAR) images for 2003-2010. We found a constant maximum displacement rate of 2.44 cm/year for the period 2003-2007 and 0.80- 0.95 cm/year for the period 2007-2010. Total SO 2 emitted is 67.0 kT for the period 2005-2010, but detection of weak SO2 degassing signals in the Andes remains challenging owing to increased noise in the South Atlantic radiation Anomaly region.

Spatio-temporal variation of anthropogenic marine debris on Chilean beaches.

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Hidalgo-Ruz, Valeria; Honorato-Zimmer, Daniela; Gatta-Rosemary, Magdalena; Nuñez, Paloma; Hinojosa, Iván A; Thiel, Martin

2018-01-01

We examined the hypothesis that in an emerging economy such as Chile the abundances of Anthropogenic Marine Debris (AMD) on beaches are increasing over time. The citizen science program Científicos de la Basura ("Litter Scientists") conducted three national surveys (2008, 2012 and 2016) to determine AMD composition, abundance, spatial patterns and temporal trends. AMD was found on all beaches along the entire Chilean coast. Highest percentages of AMD in all surveys were plastics and cigarette butts, which can be attributed to local sources (i.e. beach users). The Antofagasta region in northern Chile had the highest abundance of AMD compared with all other zones. Higher abundances of AMD were found at the upper stations from almost all zones. No significant tendency of increasing or decreasing AMD densities was observed during the 8years covered by our study, which suggests that economic development alone cannot explain temporal trends in AMD densities. Copyright © 2017 Elsevier Ltd. All rights reserved.

Natural Ventilation: A Mitigation Strategy to Reduce Overheating In Buildings under Urban Heat Island Effect in South American Cities

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Palme, Massimo; Carrasco, Claudio; Ángel Gálvez, Miguel; Inostroza, Luis

2017-10-01

Urban heat island effect often produces an increase of overheating sensation inside of buildings. To evacuate this heat, the current use of air conditioning increases the energy consumption of buildings. As a good alternative, natural ventilation is one of the best strategies to obtain indoor comfort conditions, even in summer season, if buildings and urban designs are appropriated. In this work, the overheating risk of a small house is evaluated in four South American cities: Guayaquil, Lima, Antofagasta and Valparaíso, with and without considering the UHI effect. Then, natural ventilation is assessed in order to understand the capability of this passive strategy to assure comfort inside the house. Results show that an important portion of the indoor heat can be evacuated, however the temperature rising (especially during the night) due to UHI can generate a saturation effect if appropriate technical solutions, like the increase in the air speed that can be obtained with good urban design, are not considered.

Featured Image: Extinction in Our Inner Galaxy

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Kohler, Susanna

2017-11-01

In this map of the innermost galaxy, which spans only a few square degrees at the Milky Ways center, we can seethe locations of more than 31 million objects obtained from the VISTA Variables in the Va Lctea (VVV) survey. This near-infrared atlas traces stellar populations in the inner Milky Way that are dimmed and reddened by interstellar dust and gas a process known as extinction in a predictable way. Led by Javier Alonso-Garca (University of Antofagasta and the Millennium Institute of Astrophysics in Chile), a team of scientists has now used the VVV measurements of these stars to better understand the distribution of gas and dust that causes extinction in our inner galaxy particularly in the most central, highly reddened, and crowded areas of the Milky Way. For more information, check out the paper below.CitationJavier Alonso-Garca et al 2017 ApJL 849 L13. doi:10.3847/2041-8213/aa92c3

VIOLENCIA PSICOLÓGICA EN EL NOVIAZGO EN ESTUDIANTES UNIVERSITARIOS CHILENOS: DIFERENCIAS EN EL APEGO Y LA EMPATÍA DIÁDICA

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Mónica Guzmán-González

2014-01-01

Full Text Available El propósito del estudio fue evaluar diferencias en el apego romántico y la empatía diádica en función de la presencia/ausencia de violencia psicológica perpetrada en relaciones de noviazgo entre jóvenes universitarios. La muestra constó de 470 estudiantes entre los 18 y 28 años de la ciudad de Antofagasta, Chile, quienes completaron el cuestionario de Experiencias en Relaciones Cercanas (Brennan, Clark & Shaver, 1998, el Índice de Reactividad Interpersonal para Parejas (Péloquin & Lafontaine, 2010 y la Escala de Tácticas de Conflicto (CTS2 (Straus, 1996. Los resultados permiten concluir que las personas que ejercieron violencia psicológica en el último año presentan niveles más altos de ansiedad y niveles más bajos de toma de perspectiva y preocupación empática. No se detectaron diferencias en la evitación asociada al apego.

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

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Luz Bibiana Moscoso Marín

2005-12-01

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

Past and Present Weathering Recorded in Cretaceous Shale Samples from Colombia - Implications for Paleoenvironmental Reconstructions

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Mahoney, C.; März, C.; Wagner, T.

2016-12-01

It is well known that for geochemical studies on ancient rocks, outcrop samples can be compromised by present-day weathering. This raises the fundamental question, if only outcrop samples are available, how reliable can paleoenvironmental reconstructions be? To answer this question, shale samples have been gathered from Cretaceous outcrops of the Eastern Cordillera of Colombia, and analysed by XRF and Fe speciation in order to investigate paleo-redox conditions in this margin basin of the Proto-Atlantic. The samples are consistently depleted (relative to average shale) in redox-related trace metals and in total Fe indicating oxic conditions, whereas Fe speciation (highly reactive over total Fe) indicates anoxic conditions. We ask if this depletion in trace metals and total Fe is due to a lack of primary supply from the depositional environment, or if is it caused by modern oxidative outcrop weathering in this tropical mountainous setting? Our results from artificial weathering experiments confirm that certain trace metals U, Zn and Mo are easily leached from the samples, whereas Fe is quantitatively retained in the samples due to conversion of pyrite and siderite to Fe oxides. Pristine samples from wells in the adjacent Middle Magdalena Valley Basin (MMV) also exhibit total Fe depletion, but are up to 2000-fold enriched in Mo. This combined evidence indicates that the depletion of trace metals may be due to contemporary weathering, but there has to be a paleoenvironmental reason behind the low total Fe signature. The Guiana Shield was the probable source of sediment to the Cretaceous basin. The Chemical Index of Alteration suggest the source of detrital material was initially highly weathered (average 83, maximum 95). Ancient laterites have been identified on the Guiana Shield, and retention of Fe in these laterites may explain the low Fe input into the Eastern Cordillera basin. These results confirm that trace metal-based redox proxies may be seriously affected by

Vulnerability assessment of skiing-dependent businesses to the effects of climate change in Banff and Jasper National Parks, Canada

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Reynolds, David Michael

This qualitative study examines the potential positive and negative socio-economic impacts that may emerge from the long-term effects of climate change on skiing-dependent businesses in Banff and Jasper National Parks, Canada. My goal was to determine whether or not skiing-related tourism in the parks in the 2020s and 2050s is more or less socio-economically vulnerable to the effects of climate change on snow cover, temperatures and ski season length at ski resorts in the parks. My study explored the level of awareness and personal perceptions of 60 skiing-dependent business managers about how the impact of climate change on ski resorts may influence future socio-economics of ski tourism businesses. I employed a vulnerability assessment approach and adopted some elements of grounded theory. My primary data sources are interviews with managers and the outcome of the geographical factors index (GFI). Supporting methods include: an analysis and interpretation of climate model data and an interpretation of the economic analysis of skiing in the parks. The interview data were sorted and coded to establish concepts and findings by interview questions, while the GFI model rated and ranked 24 regional ski resorts in the Canadian Cordillera. The findings answered the research questions and helped me conclude what the future socio-economic vulnerability may be of skiing-dependent businesses in the parks. The interviews revealed that managers are not informed about climate change and they have not seen any urgency to consider the effects on business. The GFI revealed that the ski resorts in the parks ranked in the top ten of 24 ski resorts in the Cordillera based on 14 common geographical factors. The economic reports suggest skiing is the foundation of the winter economy in the parks and any impact on skiing would directly impact other skiing-dependent businesses. Research indicates that the effects of climate change may have less economic impact on skiing

Alstroemeriaceae en Perú y áreas vecinas

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Anton Hofreiter

2006-10-01

Full Text Available Las Alstroemeriaceae peruanas fueron revisadas por última vez por Killip (1936. Es necesaria una nueva revisión. Cinco viajes de campo de varias semanas cada uno fueron emprendidos a Sudamérica con el fin de estudiar las plantas in situ. En el presente trabajo se describe la historia taxonómica y colección de los géneros con especial énfasis en el Perú. El área descrita no considera fronteras políticas sino unidades geográficas de acuerdo a Baumann (1988, Berry (1982, Duellman (1979, Simpson (1975, 1979 y Weigend (2002. Se reconocen cinco unidades geográficas: Región Amotape-Huancabamba (Ecuador, Perú, Cordillera Occidental (Perú, Cordillera Central (Perú, Cordillera Oriental (Bolivia, Perú y el Altiplano (Bolivia, Perú. Se brinda una clave taxonómica en inglés y español para determinar las especies del Perú. Para cada una de las especies se discute la forma típica de crecimiento y su variabilidad, preferencias de hábitat y distribución general. Se identifican las especies de Ruiz & Pavón (1802. Ellos describieron en su Flora de Chile y Perú 23 especies de Alstroemeria, 18 fueron de Perú, ahora 17 son incluidas en Bomarea, todas proceden de Perú. El género Bomarea está subdividido en 4 subgéneros: Baccata, Bomarea s. str., Sphaerine y Winchurea (Hofreiter & Tillich, 2002. Alstroemeria no es dividido en subgéneros, pero existen dos grupos reconocidos, Alstroemeria de Chile y Brasil. En el área de estudio se encuentran dos especies de Alstroemeria y 68 de Bomarea, de ellas 43 especies pertenecen al subgénero Bomarea, 9 especies al subgénero Sphaerine y 16 especies al subgénero Wichuraea. El subgénero Baccata no se encuentra en el área de estudio. Seis de las especies del género Bomarea son nuevas para la ciencia: B. amazonica, B. libertadensis, B. lopezii, B. macusanii, B. pseudopurpurea, B. weigendii.

Sr isotopes at Copahue Volcanic Center, Neuquen, Argentina: Preliminary report

International Nuclear Information System (INIS)

Linares, E.; Ostera, H.A.; Cagnoni, M.C

2001-01-01

The Copahue Volcanic Center is located in the Cordillera Principal, at 38 L.S., in the Argentina- Chilean border. Detailed geological, geochronological and structural studies were carried out during the last decade (Pesce, 1989; Delpino y Bermudez, 1993; Linares et al., 1995, 1999; Folguera y Ramos, 2000; among others). We present Sr isotopes data on the main units of the Volcanic Center, coupled with a major element geochemistry, to constrain the evolution of the volcanic center (au)

Presa con revestimiento asfáltico

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Proudfit, D. P.

1960-07-01

Full Text Available La presa denominada Montgomery se halla situada sobre el río South Platte River, a unos 8 km aguas arriba de la ciudad de Alma, del Estado de Colorado (EE. UU., y en la ladera oriental de la cordillera Continental Divide. El cuerpo o dique de esta presa está constituido por piedra, revestida con una capa de hormigón asfáltico en el paramento de contacto con el agua.

Can the Trinidad and Tobago Defence Force be Used Successfully as an Instrument of Nation Building in Trinidad and Tobago

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1994-06-03

nations face. Like Lundberg and Martin, they believe that humanitarian assistance, to needy nations, in the form of providing food, shelter , and clothing...there is the flat to rolling plateau of Patagonia which has many sheep ranches. To the west of Argentina is the Cordillera of the Andes and to the...constructing nesting islands and wildlife shelters .20 ’ Assistance was given to the Grazing Service by the CCC. Its members constructed springs and reservoirs in

Advances and trends on earthquake-triggered landslide research in Spain

OpenAIRE

García Mayordomo, Julián; Rodríguez Peces, Martín Jesús; Azañón, J.M.; Insúa Arévalo, Juan Miguel

2009-01-01

This work reviews the current situation of earthquake‐triggered landslide studies in Spain both from the point of view of regional assessment and site‐specific cases. Regional assessments have been undertaken in areas of the Betic Cordillera (South and Southeast Spain): Alcoy Basin, Lorca Basin, Granada Basin and Sierra Nevada Range; and Central Pyrenees (North Spain and Andorra). Specific studies are very scarce, outstanding those related to the Güevéjar landslide (Granada) –triggered by 175...

Prehnite-pumpellyite facies metamorphism in the Cenozoic Abanico Formation, Andes of central Chile (33°50'S): chemical and scale controls on mineral assemblages, reaction progress and the equilibrium state Metamorfismo de facies prehnita-pumpellyita en la Formación Abanico del Cenozoico, Andes centrales de Chile (33°50'S): controles químicos y de escala sobre las asociaciones minerales, el progreso de la reacción y el estado de equilibrio

OpenAIRE

Marcia Muñoz; Luis Aguirre; Mario Vergara; Alain Demant; Francisco Fuentes; Andrés Fock

2010-01-01

In the El Volcan and Rodeo de los Bueyes areas, Andean Principal Cordillera (east of Santiago; 33°50'S), an Upper Oligocene-Lower Miocene volcanic series belonging to the Abanico Formation (Late Eocene-Early Miocene) is exposed. The rock successions outcropping in both areas, ca. 3,300 m total thickness, have been affected by very low-grade, non-deformative metamorphism in the prehnite-pumpellyite facies. This is represented by the widespread development of secondary mineral assemblages compo...

Prehnite-pumpellyite facies metamorphism in the Cenozoic Abanico Formation, Andes of central Chile (33°50'S): chemical and scale controls on mineral assemblages, reaction progress and the equilibrium state

OpenAIRE

Muñoz,Marcia; Aguirre,Luis; Vergara,Mario; Demant,Alain; Fuentes,Francisco; Fock,Andrés

2010-01-01

In the El Volcan and Rodeo de los Bueyes areas, Andean Principal Cordillera (east of Santiago; 33°50'S), an Upper Oligocene-Lower Miocene volcanic series belonging to the Abanico Formation (Late Eocene-Early Miocene) is exposed. The rock successions outcropping in both areas, ca. 3,300 m total thickness, have been affected by very low-grade, non-deformative metamorphism in the prehnite-pumpellyite facies. This is represented by the widespread development of secondary mineral assemblages compo...

Description of Lutzomyia velezi, a new species of phlebotomine sand fly (Diptera: Psychodidae) from the Department of Antioquia, Colombia

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Bejarano, Eduar Elías; Vivero, Rafael José; Uribe, Sandra

2010-01-01

The phlebotomine sand fly Lutzomyia velezi sp.nov. was described and illustrated from male specimens collected by light trap in the Reserva Natural Cañon del Río Claro in the Central Cordillera of the Colombian Andes. The new species belongs to the series sanguinaria of the subgenus Helcocyrtomyia, which is represented in Colombia by Lutzomyia cirrita, Lutzomyia hartmanni, Lutzomyia sanguinaria, Lutzomyia scorzai, Lutzomyia sp. of Pichindé and Lutzomyia tortura. The new species can be differe...

EXTINCTION RISK OR LACK OF SAMPLING IN A THREATENED SPECIES: GENETIC STRUCTURE AND ENVIRONMENTAL SUITABILITY OF THE NEOTROPICAL FROG PRISTIMANTIS PENELOPUS (ANURA: CRAUGASTORIDAE

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ADRIANA RESTREPO

Full Text Available ABSTRACT IUCN Red Lists have been a valuable tool to prioritize conservation plans in endemic neotropical frogs. However, many areas in this region are poorly known in terms of their diversity and endemism. Based on examined museum specimens of the threatened species Pristimantis penelopus we revised its geographic distribution and determined the habitat suitability using niche modeling techniques. Using a mitochondrial fragment of COI gene, we determine the phylogenetic position and the extent of the genetic variation across its distribution in Colombia. We present the first records of P. penelopus for the Cordillera Oriental, the western versant of Cordillera Occidental and the northern portion of the Cauca river basin. Based on the molecular phylogenetic analysis, Pristimantis penelopus belongs to the P. ridens series sensu (Padial et al., 2014. The mean of intraspecific genetic variation is 2.1% and the variation among population ranges between 2.3 and 3.5%. The genetic distance between the western populations and the Magdalena Valley populations suggests a potential phylogeographic break in northwestern Antioquia. We expand the realized distribution by 258 kilometers north, 200 km east and 223 km northwest. Based on our results and according to the IUCN criteria we propose a new category for the species and highlight the need to increase the surveys in poorly known regions to better understand the geographic distribution and conservation status of listed species.

Kinetically limited weathering at low denudation rates in semiarid climatic conditions

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Schoonejans, Jérôme; Vanacker, Veerle; Opfergelt, Sophie; Ameijeiras-Mariño, Yolanda; Christl, Marcus

2016-02-01

Biogeochemical cycling within the Critical Zone depends on the interactions between minerals and fluids controlling chemical weathering and physical erosion rates. In this study, we explore the role of water availability in controlling soil chemical weathering in semiarid climatic conditions. Weathering rates and intensities were evaluated for nine soil profiles located on convex ridge crests of three mountain ranges in the Spanish Betic Cordillera. We combine a geochemical mass balance with 10Be cosmogenic nuclides to constrain chemical weathering intensities and long-term denudation rates. As such, this study presents new data on chemical weathering and 10Be-derived denudation for understudied semiarid climate systems. In the Betic Cordillera, chemical weathering intensities are relatively low (~5 to 30% of the total denudation of the soil) and negatively correlated with the magnitude of the water deficit in soils. Chemical mass losses are inversely related to denudation rates (14-109 mm/kyr) and positively to soil thickness (14-58 cm); these results are consistent with kinetic limitation of chemical weathering rates. A worldwide compilation of chemical weathering data suggests that soil water balance may regulate the coupling between chemical weathering and physical erosion by modulating soil solute fluxes. Therefore, future landscape evolution models that seek to link chemical weathering and physical erosion should include soil water flux as an essential driver of weathering.

Sequential chemical extraction of heavy metals in a study of the chemical alteration of mine tailings at Ticapampa (Huaraz, Peru); Extraccion quimica secuencial de metales pesados en el estudio de alteracion quimica de relaves de mina en Ticapampa (Huaraz, Peru)

Energy Technology Data Exchange (ETDEWEB)

Jara Facundo, M. A.

2011-07-01

The upper reaches of the Rio Santa (Huaraz, Peru) are highly affected by the mining activities of generally small and very small mining companies located in two specific areas, Cordillera Blanca, and Cordillera Negra, with the largest mining claims located in the districts of Recuay and Ticapampa. To assess the mobility and bioavailability of heavy metals in the abandoned tailings pond belonging to the Alianza mining company in the district of Ticapampa, and to identify the fractions to which they are associated we applied a sequential chemical extraction. The results were compared with studies into their mineralogical characterization, a quantitative chemical analysis and a determination of potential acidity and potential neutralization by the ABA (acid-base accounting) method applied to samples of tailings. The sequential extraction procedure confirmed the mode of general alteration observed in the area through mineralogical studies: a relatively easy mobility of Pb, and Cd, and considerable immobility with regard to Ag, Cr and Co, as well as an intermediate mobility of Cu, Zn, and As. Significant cadmium and lead contents found in the most mobile fractions of the tailings may represent an environmental threat, bearing in mind the toxic nature of these elements. Despite the low mobility of arsenic, the total quantities of this element are so high that the waters of the Rio Santa are being affected. (Author) 22 refs.

Geochronologic synthesis of the Piedra Alta Terrane, Uruguay

International Nuclear Information System (INIS)

Preciozzi, F.; Peel, E.

2006-01-01

In the Pre cordillera of Córdoba there are sixteen bands of ductile deformation, which allows tectonic significance assign them to four groups. One of them, which belongs to Deformation Gaza Tunnels, consists of post metamorphic strips uprooting of Orogen Pampeano Cambrian reverse nature, produced by convergent general shear (transpressional), related to collisional stages terrain Posthumous Pampa against Gondwana margin, and famatinian subduction. New radiometric data obtained by the K / Ar method amphiboles and micas allow better narrow activity tectonics of the strip, which would have nucleated after the M2 metamorphic peak (ca. 534 Ma), uprooted the Orogen Cambrian and Ordovician exhumándolo up early (onset of subduction Famatinian), when located the Charquina (474 ​​Ma) granodiorite. The period of tectonic activity FDLT (ca. 64 Ma), coincide with the approach of land Cuyania the Gondwana margin, prior to placement and final collision in the Middle to Late Ordovician. At the same time, in the field Pampeano they would be producing con tractional stages end collision with terrain Pampa the western margin of Gondwana. Subsequently, the FDLT would have cooled to the middle Silurian, when the Sierras de Cordoba and San Luis They continued their exhumation through isotherm muscovite. After cooling this generalized, deformation occurs and Devonian magmatism that penetrativamente affected the Pre cordillera eastern

Burmeistera minutiflora (Campanulaceae-Lobelioideae, a new species from the high Andes of Antioquia (Colombia with the smallest flowers in the genus

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Garzón Venegas, Javier

2012-12-01

Full Text Available Burmeistera minutiflora (Campanulaceae-Lobelioideae, a new species of sect. Barbatae, is here described, illustrated, and keyed out with respect to other species of the genus with small flowers (i.e. corolla tube < 1 cm long. The new species is a small herb that grows in the understory of remnants of cloud montane forests of the Western cordillera of Antioquia, Colombia. The dimensions of the corolla and the berries correspond without doubts to the smallest size of reproductive structures in the genus. The small floral size contrasts with the colorful, bright red and yellow corollas.

Se describe Burmeistera minutiflora (Campanulaceae-Lobelioideae, una nueva especie de la sect. Barbatae, y se ilustra e incluye en una clave en la que se contrasta con otras especies de flores diminutas (i.e. con corola < 1 cm. La nueva especie es una hierba pequeña, que crece en el sotobosque de remanentes de bosques nublados de la Cordillera Occidental de Antioquia, Colombia. Las pequeñas dimensiones de la corola y de las bayas corresponden si lugar a dudas a las estructuras reproductivas de menor tamaño conocidas en el género. El pequeño tamaño de las flores contrasta con la vivacidad de las corolas rojas brillantes y amarillas.

Evidence of an upper ordovician thermo-metamorphic event in the SW-Corner of the Cantabrian Mountains (N-Spain

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Krumm, S.

1992-12-01

Full Text Available According to Illite «crystallinity» (IC data, the metamorphic evolution of the SW Cantabrian Mountains took place in several steps. After a Precambrian deformation with accompanying low-grade metamorphism a thermal event during the Upper Ordovician affected the Cambro-Ordovician sediments. This event is marked by anchizonal IC values in the Pre-Silurian sequence contrasting the diagenetic data obtained from Siluro-Devonian rocks.Apparently, the metamorphic history in that part of the Cantabrian Mountains ended during the Late Ordovician, a Hercynian metamorphism cannot be proven conclusively.Segun la cristalinidad de Illita (IC la evolución metamórfica de la zona sudoeste de la Cordillera Cantábrica tuvo lugar en varias etapas. Siguiendo una deformación precámbrica con un metamorfismo de bajo grado, un evento térmico durante el Ordovícico Superior afecto a la secuencia Cambro-Ordovícica. Este evento esta marcado en las rocas pre-Silúricas por valores de IC indicando la anchizona. Estos datos contrastan con valores obtenidos de la secuencia Siluro-Devónica, que son característicos de la diagénesis.Aparentemente, la evolución metamórfica del sudoeste de la Cordillera Cantábrica termino durante el Ordovícico, un metamorfismo Hercínico no pudo ser comprobado.

Relationships between mineralization and silicic volcanism in the central Andes

Energy Technology Data Exchange (ETDEWEB)

Francis, P.W.; Halls, C.; Baker, M.C.W.

1983-10-01

Studies of late Tertiary silicic volcanic centers in the Western and Eastern Cordilleras of the Central Andes show that three volcanic environments are appropriate sites for mineralization: (1) ring-fracture extrusions post-dating large calderas; (2) similar extrusions within ignimbrite shields; and (3) isolated, small silicic volcanoes. Subvolcanic tin mineralization in the Eastern Cordillera is located in silicic stocks and associated breccias of Miocene age. The Cerro Rico stock, Potosi, Bolivia, contains tin and silver mineralization and has an intrusion age apparently millions of years younger than that of the associated Kari Kari caldera. Similar age relationships between mineralization and caldera formation have been described from the San Juan province, Colorado. The vein deposits of Chocaya, southern Bolivia, were emplaced in the lower part of an ignimbrite shield, a type of volcanic edifice as yet unrecognized in comparable areas of silicic volcanism. The El Salvador porphyry copper deposit, Chile, is related to silicic stocks which may have been intruded along a caldera ring fracture. Existing models for the genesis of porphyry copper deposits suggest that they formed in granodioritic stocks located in the infrastructure of andesitic stratovolcanoes. The dome of La Soufriere, Guadeloupe is proposed as a modern analog for the surface expression of subvolcanic mineralization processes, the phreatic eruptions there suggesting the formation of hydrothermal breccia bodies in depth.

Metamorfismo de baja presión, su relación con el desarrollo de la Cuenca Puncoviscana, plutonismo y régimen tectónico. Argentina

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Durand, F. R.

1992-12-01

Full Text Available In the Cordillera Oriental Argentina (22 and 26° S, the Puncoviscana Formation Basin was developed, in which an extensional tectonic setting would had been supported from Upper Precambrian to Middle Ordovician. That is suggested by the limited crustal thickening, the insignificant uplift after deformation, the sedimentary-synchronous basic-alkalic lavas and the growth of a low-pressure high-temperature metamorphism that culminates in anatectic migmatites, which have no explanation by the only magmatic heat derived from the little trondhjemite-granodiorite diapires intruded during the Middle Ordovician.En la Cordillera Oriental Argentina (22 y 26° S, se desarrolló la cuenca de la Formación Puncoviscana, en la que predominó un régimen tectónico de extensión cortical, que se habría mantenido desde el Precámbrico Superior hasta el Ordovícico Medio, sugerido por el escaso engrosamiento cortical, el insignificante ascenso después de la deformación y las capas de lavas básicas alcalinas intercaladas. El desarrollo de un metamorfismo de baja presión y alta temperatura culmina en migmatitas anatécticas, que no pueden explicarse por la sola acción del calor magmático derivado de los pequeños diapiros trondhjemíticos y granodioríticos, intruidos durante el Ordovícico Medio.

Carbon storage and long-term rate of accumulation in high-altitude Andean peatlands of Bolivia

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J.A. Hribljan

2015-11-01

Full Text Available (1 The high-altitude (4,500+ m Andean mountain range of north-western Bolivia contains many peatlands. Despite heavy grazing pressure and potential damage from climate change, little is known about these peatlands. Our objective was to quantify carbon pools, basal ages and long-term peat accumulation rates in peatlands in two areas of the arid puna ecoregion of Bolivia: near the village of Manasaya in the Sajama National Park (Cordillera Occidentale, and in the Tuni Condoriri National Park (Cordillera Real. (2 We cored to 5 m depth in the Manasaya peatland, whose age at 5 m was ca. 3,675 yr. BP with a LARCA of 47 g m-2 yr-1. However, probing indicated that the maximum depth was 7–10 m with a total estimated (by extrapolation carbon stock of 1,040 Mg ha-1. The Tuni peat body was 5.5 m thick and initiated ca. 2,560 cal. yr. BP. The peatland carbon stock was 572 Mg ha-1 with a long-term rate of carbon accumulation (LARCA of 37 g m-2 yr-1. (3 Despite the dry environment of the Bolivian puna, the region contains numerous peatlands with high carbon stocks and rapid carbon accumulation rates. These peatlands are heavily used for llama and alpaca grazing.

EL NORTE GRANDE DE CHILE: LA DEFINICIÓN HISTÓRICA DE SUS LÍMITES, ZONAS Y LÍNEAS DE FRONTERAS, Y LA IMPORTANCIA DE LAS CIUDADES COMO GEOSÍMBOLOS FRONTERIZOS

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SERGIO GONZÁLEZ

2011-05-01

Full Text Available Resumen Este artículo analiza el desarrollo histórico del Norte Grande de Chile durante el siglo diecinueve y el primer tercio del siglo veinte, con sus diversas zonas de fronteras y límites fronterizos respectivos, donde ciertos geosímbolos han tenido un papel muy relevante como demarcadores. Sin embargo, considera la urbanización de la frontera como un proceso clave en la reproducción social y cultural del estado-nación. Destaca en ese proceso de urbanización del Norte Grande de Chile, la importancia del desierto de Atacama y de algunas ciudades como geosímbolos, analiza los casos de Antofagasta, Iquique y Arica. También discute teóricamente la diferencia entre límite fronterizo y línea de frontera, al primer concepto lo asocia a una problemática propia del siglo diecinueve y veinte, donde la frontera es un rígido demarcador de la otredad y, el segundo concepto, lo asocia al fenómeno de la globalización y a la posibilidad de construir en las fronteras urbanizadas alianzas estratégicas y regiones asociativas transfronterizas. Conceptos clave: zonas de fronteras, límites fronterizos, líneas de frontera, geosímbolos, transfrontera. Abstract This article analyzes the historical development of the Big North of Chile during the 19th century and the first third of the 20th century, with its own various border areas and frontier boundaries, where certain geosymbols have had a very relevant role demarcating. However, it considers the urbanization of the frontier as a key process in the social and cultural reproduction of the nation-state. It emphasizes in that process of urbanization of the Big North of Chile, the importance of the Atacama Desert and some cities as geosymbols, it analyzes the cases of Antofagasta, Iquique and Arica. It also theoretically discusses the difference between the frontier boundary and border line, it associates the first concept with problematic issues typical of the 19th and 20th centuries, where the

Evaluación en ambiente natural, del uso de biopelículas marinas en el asentamiento larval de Argopecten purpuratus (Lamarck, 1819 Evaluation in natural environment of use of marine biofilms, in the larval settlement of Argopecten purpuratus (Lamarck, 1819

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Marcela Cantillánez

2010-01-01

Full Text Available En una granja marina ubicada colindante con el área de reserva marina “La Rinconada” (Antofagasta, Chile, se evaluó el asentamiento larval del pectínido Argopecten purpuratus sobre colectores impregnados con películas multi-específicas, de las diatomeas Navicula sp. y Amphora sp., y de la cepa bacteriana NC1, aisladas desde colectores utilizados en captaciones comerciales de esta especie que presentaron altos índices de fijación, y que bajo condiciones controladas de criadero y laboratorio, han mostrando altos niveles de asentamiento larval. Los resultados obtenidos con el uso de estas biopelículas, sobre colectores instalados en forma paralela a los utilizados por la empresa para la captación de semilla con fines comerciales, no mostraron diferencias significativas entre los diferentes tratamientos probados y el control, respecto a las fijaciones ocurridas en un lapso de 30 días de inmersión. Se discute, debido a los tiempos que demandaron las larvas de la primera cohorte en asentarse sobre los colectores tratados, un posible reemplazo de las biopelículas utilizadas, por otra común en todos ellos y atractiva para el asentamiento de las larvas, como causa de la ausencia de efectos significativos de los tratamientos probados en el medio natural. Se recomienda la necesidad de establecer el tiempo de permanencia, en el ambiente natural, de las biopelículas impregnadas a los colectores en laboratorio.In a commercial farm located near the Marine Reserve “La Rinconada” (Antofagasta, Chile the larval settlement of Argopecten purpuratus on artificial collectors impregnated with multiespecific films of marine diatoms Navicula sp. and Amphora sp. and, bacterial strain NC1 were evaluated, These biofilms were isolates from artificial collector used in commercial activities with highest index of settlement in hatchery and laboratory conditions. The results to use this biofilms in collectors installed in same condition of commercial

Una nueva especie de Lepidoblepharis (Sauria, Gekkonidae de la Cordillera Central de Colombia Una nueva especie de Lepidoblepharis (Sauria, Gekkonidae de la Cordillera Central de Colombia

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Ayala Stephen C.

1986-12-01

Full Text Available A third Lepidoblepharis is described from temperate elevations in the Colombian Andes. Unlike L. colombianus or L. duolepis, the new species from central Antioquia is a small, moderately short toed species, reaching about 30 mm snout-vent length. Most specimens have prominent rust colored dorsolateral stripes on the tail. Una tercera especie de Lepidoblepharis se describe de zonas templadas de los Andes de Colombia. A diferencia de L. colombianus o L. duolepis, la nueva especie de Antioquia es una especie de menor tamaño que alcanza unos 30 mm de longitud rostro-ano, y los dedos son moderadamente cortos. La mayoría de los ejemplares tiene franjas dorsolaterales muy notorias de color herrumbre en la cola.

DEFORMACION CORTICAL Y PELIGRO SISMICO ASOCIADO A LA FALLA SAN RAMON EN EL FRENTE CORDILLERANO DE SANTIAGO, CHILE CENTRAL (33°S)

OpenAIRE

RAULD PLOTT, RODRIGO ANDRES; RAULD PLOTT, RODRIGO ANDRES

2011-01-01

1) El orógeno Andino es fundamentalmente bi-vergente, incluyendo un gran sistema de fallas inversas cabalgantes en el frente occidental chileno, que son sintéticas con respecto al acoplamiento tectónico causante de la orogenia Andina (subducción de la placa Nazca, oceánica, bajo la placa Sudamericana, continental); 2) El funcionamiento del Cabalgamiento Andino Occidental (West Andean Thrust, WAT), documentado por la estructura con vergencia oeste de la Cordillera Principal en Chile, tiene ...

Evaluación, implementación de sistema dispacht: control de equipos en minería a cielo abierto, en la empresa minera coripuno s.a.c.

OpenAIRE

Requejo Mejía, Paul Alexander

2016-01-01

Mining Untuca Unit is located in the southeast of Peru , on the eastern flank of the Eastern Cordillera de los Andes del Sur, having NW -SE orientation and consists of peaks exceeding 4,000 meters to reach altitudes greater than 5,000 m , presenting many perpetual snow. Politically is located in the District of Quiaca, Province of Sandia, Department of Puno. The work carried out show that the area is positive, white for the location of economic interest and through regional geological interp...

Controles y guías en la Exploración de cuerpos Argentíferos en Skarn del yacimiento de Uchucchacua Cajatambo-Lima

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Martinez Rosales, Pascual; Martinez Rosales, Pascual; Martinez Rosales, Pascual

1986-01-01

El Yacimiento de Ag-Mn (Pb-Zn) de Uchucchacua está ubicado en el extremo sur de la Cordillera Raura, Provincia de Cajatambo, Departamento de Lima. Consiste principalmente en una serie de filones tales como las vetas Luz, Socorro, Camucha, Rosa, Casualidad, Plomopampa, Huantajalla, Mercedes y Candelaria. También se conocen cuerpos de reemplazamiento adyacentes a las vetas corno son Rosa Norte, Viviana e Irma; emplazadas en calizas y margas de la Formación Jumasha del Cretáceo Superior. L...

The awakening of Kumpanam: History and myth at an environmental conflict in the Amazonia

OpenAIRE

Garra, Simone

2012-01-01

In the last years the Awajún people, settled in the Río Cenepa watershed (Department of Amazonas, Peru) are struggling to defend their land from the impact of the mining activities in the Cordillera del Condor mountains. The myth of Kumpanan, an ancestor associated to the homonymous pick, located in the mining area, has been revitalized, with a new meaning, mirroring the current social and environmental contingency of the area. This contributes to rethink the linkages existing between «histor...

desertification process altoandina olleros district area (Huaraz, ancash)

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Cruz Reyes, Fray Masias

2014-01-01

The territory of Olleros district is considered high Andean, and extends from 3600 masl. Olleros bounded on the east by the Cordillera Blanca, so the entire territory corresponde to the western side of this, which is characterized by steep slopes over 20% of its length. Being a very rugged territory because of the steady flow of water from the numerous ravines or talwegs (in this case: Mashuan, Aco, Arzobispo, Puyhuan, Rurec and Arhuey), there can be distinguished four natural regions: Quech...

Island of Luzon, Philippines

Science.gov (United States)

1990-01-01

In this north to south view of the Island of Luzon, Philippines (13.0N, 120.0E), the prominent Cordillera Central mountain range where gold, copper and silver are mined. The several large rivers that drain this region normally carry a heavy silt load to the sea but the absence of sediment plumes in this view is evidence of hot dry weather and lack of recent rains. Manila, the capital city is just visible at the south end of the island.

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

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Rejas, J. G.

2014-12-01

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

Efectos del prejuicio sexual en la salud mental de gays y lesbianas, en la ciudad de Antofagasta, Chile

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Fabiola Gómez

Full Text Available Este artículo caracteriza diferencias en relación al prejuicio sexual en la salud mental de personas homosexuales y heterosexuales. En el estudio se incluyeron medidas de Bienestar Psicológico y Bienestar Social, así como medidas de Distrés Psicológico (SCL-90-R. La muestra con la que se ha trabajado está compuesta por 110 personas (55 homosexuales y 55 heterosexuales, cuyas edades fluctuan entre 18 y 49 años. Si bien no se encontraron diferencias en la salud mental de personas homosexuales y heterosexuales, sí se reportaron diferencias en los análisis segmentados por sexo y orientación sexual. Por su parte, en este estudio, el prejuicio sexual apareció relacionado significativamente con algunas de las dimensiones de salud mental indagadas.

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

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Enrique Arbeláez-Cortés

2011-06-01

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

Tortugas del Cretácico Inferior de la Cuenca Vasco-Cantábrica: el registro Hauteriviense-Barremiense de Vega de Pas (Cantabria)

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Pérez García, Adán; Murelaga, Xabier

2013-01-01

El registro de tortugas del Cretácico Inferior de España es muy abundante y diverso. Hasta ahora todos los hallazgos provenían de la Cordillera Ibérica. Se presenta aquí material de tortugas hallado en la Cuenca Vasco- Cantábrica. Estos ejemplares, provenientes del Hauteriviense-Barremiense de la Formación Vega de Pas (Cantabria), corresponden a placas tanto del espaldar como del plastrón. Se reconoce la presencia de un representante indeterminado de Eucryptodira, que difier...

Caracterización de dos sistemas de abanicos aluviales húmedos en el Terciario de la Depresión Intermedia (Cuenca-Guadalajara)

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Torres Pérez-Hidalgo, Trinidad José

1986-01-01

En este trabajo se comparan las características de dos abanicos aluviales del Primer Ciclo Neógeno (Ageniense superior-Aragoniense inferior) de la Depresion Intermedia. Estos abanicos tienen una serie de características comunes como: área fuente en la Cordillera Ibérica, períodos alternantes de funcinamiento de canales de baja y alta sinuosidad e interdigitación dista1 con depósitos lacustres de yesos bioturbados. Se diferencian en la orientación de paleocorrientes y presenc...

Los sistemas aluviales miocenos del borde noreste de la Cuenca de Madrid: sector Cifuentes - Las Inviernas (Guadalajara)

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Alonso-Zarza, Ana María; Calvo Sorando, José Pedro; García del Cura, M. Ángeles; Hoyos,, M.

1990-01-01

El relleno mioceno en el borde noreste de la Cuenca de Madrid aparece constituido por varios complejos detríticos que se desarrollan a partir de los relieves mesozoicos de la Cordillera Ibérica, que constituye en este área el borde de la cuenca terciaria. Se definen esencialmente dos tipos de sistemas deposicionales dentro de las áreas marginales de la cuenca: abanicos aluviales y depósitos de ladera. Dentro de los primeros, que constituyen los elementos de mayor envergadura y los contribu...

Plan de comercialización Heliraid Patagonia

OpenAIRE

Mella, Natalia

2012-01-01

La Patagonia Argentina Austral, es considerada un icono a nivel mundial, reúne un conjunto de provincias y aspectos naturales únicos en el mundo1. La Cordillera de los Antes, sus paisajes, su geografía, y su historia. Muchos han sido los aventureros que dieron su vida por explorar y conocer esta zona. Y no todos vivieron para contarlo. Tradicionalmente, la Patagonia se caracterizaba por un escaso desarrollo comercial a raíz de los altos costos y su inaccesibilidad geográfica. Hoy, el desarrol...

CARACTERÍSTICAS NUTRICIONALES Y ANTIOXIDANTES DE LA FRUTA CURUBA LARGA (Passiflora mollisima Bailey)

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CHAPARRO R, DIANA CAROLINA; MALDONADO C, MARIA ELENA; FRANCO L, MARÍA CAMILA; URANGO M, LUZ AMPARO

2015-01-01

La presente revisión muestra el valor nutricional y el impacto para la salud humana del consumo de la fruta curuba larga (Passiflora mollisima Bailey), con base a las características nutricionales y antioxidantes. Pertenece a la familia de las pasifloráceas, es originaria de la zona andina del continente americano y en Colombia se cultiva principalmente en las cordilleras oriental y occidental. Esta fruta es fuente de vitaminas A, C y riboflavina; contiene potasio, fósforo, magnesio, sodio, c...

A review of the albidohirta group of Ptilothrix (Hymenoptera: Apidae: Emphorini

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Arturo ROIG ALSINA

2007-01-01

Full Text Available El grupo albidohirta de Ptilothrix Smith incluye tres especies: Ptilothrix albidohirta Brèthes, P. concolor sp. nov. y P. nemoralis sp. nov. Este grupo se conoce del oeste y norte de la Argentina y del centro de Bolivia. Una de sus especies, P. albidohirta, llega hasta los 3.600 m s.n.m. en la cordillera de los Andes, en tanto que las otras dos especies habitan en el llano. Se caracteriza el grupo y se describen e ilustran las especies.

Caracterización preliminar de la lepidopterofauna (insecta: rophalocera) presente en la reserva privada: refugio del oso de anteojos (Calvario –Meta), Colombia

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Ruth Castillo; Diana Cabrera; Elizabeth Lombana

2011-01-01

Ubicada en el piedemonte de la cordillera Oriental, la reserva privada: Refugio del Oso de Anteojos, se encuentra sujeta a presión antrópicalocal representada por deforestación, quemas,pastoreo y caza de fauna silvestre. Por tanto, es necesario conocer el estado de conservación de algunas áreas mediante el empleo de organismos bioindicadores como los Lepidopteros (Rhopalocera). Los muestreos se realizaron en los meses de mayo, junio, julio y septiembre de 2008, en cuatro zonas características...

Geología de la región del Cerro Guanaquero, Río Diamante, Mendoza

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Federico Fuentes; Victor A. Ramos

2008-01-01

El estudio realizado presenta nuevos datos sobre un sector poco conocido de la Cordillera Principal de Mendoza, en la alta cuenca del río Diamante en las adyacencias del cerro Guanaquero, y los primeros datos geocronológicos de sus rocas volcánicas. Las unidades geológicas presentes en el área se dividen en cuatro grupos principales: secuencias sedimentarias mesozoicas marinas y continentales intensamente plegadas y falladas; intrusivos y volcanitas intermedias de edad neógena; rocas volcánic...

Geología de la región del Cerro Guanaquero, Río Diamante, Mendoza Geology of Cerro Guanaquero region, Diamante River, Mendoza

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Federico Fuentes; Victor A. Ramos

2008-01-01

El estudio realizado presenta nuevos datos sobre un sector poco conocido de la Cordillera Principal de Mendoza, en la alta cuenca del río Diamante en las adyacencias del cerro Guanaquero, y los primeros datos geocronológicos de sus rocas volcánicas. Las unidades geológicas presentes en el área se dividen en cuatro grupos principales: secuencias sedimentarias mesozoicas marinas y continentales intensamente plegadas y falladas; intrusivos y volcanitas intermedias de edad neógena; rocas volcánic...

A new genus of Platynini (Coleoptera: Carabidae) from Argentina

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ROIG-JUÑENT, Sergio

2003-01-01

Los Platynini constituyen un grupo de carábidos distribuidos ampliamente en América del Sur, existiendo la mayor diversidad de especies en las regiones tropicales de altura de Los Andes. En la Argentina y Chile, la mayoría de las especies de Platynini se hallan distribuidas en áreas extracordilleranas, conociéndose pocos datos para la región Andina. A partir de recolecciones realizadas en la Precordillera y Cordillera de los Andes en Mendoza (Argentina), se hallaron ejemplares pertenecientes ...

Cuando los muiscas diversificaron la agricultura y crearon el intercambio

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Carl Henrik Langebaek

1985-02-01

Full Text Available Al comienzo del siglo XVI y de la conquista del centro de la actual Colombia, los españoles encontraron un grupo indígena, los muiscas, que habitaban en los valles interandinos fríos y en las tierras adyacentes de la cordillera Oriental. Su territorio abarcaba una amplia porción del ramal andino, desde los páramos de Sumapaz, al sur, hasta el valle transversal del Chicamocha, al norte, en los actuales departamentos de Cundinamarca y Boyacá.

Asynchronous Glacial Chronologies in the Central Andes (15-40°S) and Paleoclimatic Implications

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Zech, R.; Kull, C.; Kubik, P. W.; Veit, H.

2006-12-01

We have established glacial chronologies along a N-S transect over the Central Andes using 10Be surface exposure dating. Our results show that maximum glacial advances occurred asynchronously and reflect the varying influence and shifts of the major atmospheric circulation systems during the Late Quaternary: the tropical circulation in the north and the westerlies in the south. In Bolivia (three research areas in the Cordillera Real and the Cordillera Cochabamba, ~15°S) glacial advances could be dated to ~20 and 12 ka BP. This is in good agreement with published exposure age data from moraines in Bolivia and Peru (provided that all ages are calculated following the same scaling system). Accordingly, the maximum glaciation there probably occurred roughly synchronous to the temperature minimum of the global Last Glacial Maximum (LGM) and the lateglacial cold reversals. Strict correlation with neither the Younger Dryas in the northern hemisphere, nor the Antarctic Cold Reversal is possible due to the current systematic exposure age uncertainties (~10%). Glacier-Climate-Modelling corroborates the sensitivity of the reconstructed glaciers to temperature changes, rather than precipitation. On the contrary, there is good evidence for the dominant role of precipitation changes on the glacial chronologies in the lee of the Cordillera Occidental, i.e. on the Altiplano and further south. The pronounced lateglacial wet phase, which is well documented in lake transgression phases as far south as 28°S (-> tropical moisture source), seems to have caused glacial advances even at ~30°S. In two research areas in Chile at that latitude, we were able to date several lateglacial moraines. Besides, the maximum datable glaciation there occurred at ~30 ka BP. That is significantly earlier than the LGM (sensu strictu) and points to favourable climate conditions for glaciation at that time (particularly increased precipitation). We conclude that the westerlies were more intensive or

Pliocene and Pleistocene chronostratigraphy of continental sediments underlying the Altiplano at La Paz, Bolivia

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Roberts, Nicholas J.; Barendregt, René W.; Clague, John J.

2018-06-01

Continental sediments underlying the Altiplano plateau provide insight into the late Cenozoic evolution of the Central Andes. We characterize the magnetostratigraphy and lithostratigraphy of the upper part of this fill sequence along a transect extending southwestward from the Cordillera Real at La Paz, Bolivia, where it is best exposed. Multiple polarity reversals and the locally extensive, 2.74-Ma Chijini Tuff enable correlation between our six sections and three previously reported sections. The tuff ties the composite polarity sequence to the geomagnetic polarity time scale, demonstrating that the stratigraphic record extends from the latest Gilbert Chron (ca. 3.8 Ma) to the late Olduvai subchron (ca. 1.8 Ma), or possibly Jaramillo subchron (ca. 1.0 Ma). The sequence provides Earth's longest known record of low-latitude glaciation and the only record of Pliocene tropical glaciation. It includes evidence for 16 late Pliocene and Early Pleistocene glaciations, separated by interglacials of sufficient length (>103-104 a) to produce mature soil profiles. Successively larger ice caps formed directly before, during, and after the globally warm mid-Piacenzian (3.265-3.025 Ma), and throughout Plio-Pleistocene climate deterioration. The late Pliocene glacial units predate the onset of widespread Northern Hemisphere continental glaciation and in most cases unambiguously correspond to specific cool peaks of the astronomically tuned, benthic oxygen isotope (δ18O) record, including marine isotope stages MG2, M2, KM2, and G10. The glacial events broadly coincide with those nearer both poles, suggesting inter-hemispheric climate linkages. The early formation and subsequent expansion of ice caps beyond glacier margins of the Last Glacial Maximum suggest that the Cordillera Real likely attained its modern height before ca. 3.4 Ma. The number and timing of glaciations, and long-term sediment accumulation and incision rates suggest that the local Altiplano surface formed by ca

On the Origin of Pantepui montane biotas: A Perspective Based on the Phylogeny of Aulacorhynchus toucanets.

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Elisa Bonaccorso

Full Text Available To understand the origin of Pantepui montane biotas, we studied the biogeography of toucanets in the genus Aulacorhynchus. These birds are ideal for analyzing historical relationships among Neotropical montane regions, given their geographic distribution from Mexico south to Bolivia, including northern Venezuela (Cordillera de la Costa, and the Pantepui. Analyses were based on molecular phylogenies using mitochondrial and nuclear DNA sequences. Topology tests were applied to compare alternative hypotheses that may explain the current distribution of Aulacorhynchus toucanets, in the context of previous hypotheses of the origin of Pantepui montane biotas. Biogeographic reconstructions in RASP and Lagrange were used to estimate the ancestral area of the genus, and an analysis in BEAST was used to estimate a time framework for its diversification. A sister relationship between the Pantepui and Andes+Cordillera de la Costa was significantly more likely than topologies indicating other hypothesis for the origin of Pantepui populations. The Andes was inferred as the ancestral area for Aulacorhynchus, and the group has diversified since the late Miocene. The biogeographic patterns found herein, in which the Andes are the source for biotas of other regions, are consistent with those found for flowerpiercers and tanagers, and do not support the hypothesis of the geologically old Pantepui as a source of Neotropical montain diversity. Based on the high potential for cryptic speciation and isolation of Pantepui populations, we consider that phylogenetic studies of additional taxa are important from a conservation perspective.

Nuevas evidencias de la presencia del Oso Andino (Tremarctos ornatus en las Yungas de Puno, el registro más austral de Perú

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Gisella Márquez

2011-05-01

Full Text Available El oso de anteojos Tremarctos ornatus es el único representante de la familia Ursidae en Suramérica. La población más grande y de distribución continua del oso andino en el Perú, se localiza en la ladera oriental de la cordillera oriental, incluyendo al departamento de Puno, donde casi todos los registros de esta especie provienen solamente de encuestas. Se describe aquí dos registros indirectos de la presencia del oso en el departamento de Puno, obtenidos en agosto del año 2009. El primer registro corresponde a una feca, con semillas perteneciente a la familia Lauraceae, encontrada en Yanacocha; y el segundo registro corresponde a unas marcas de garras del oso hallado en Challohuma. Este último representa el registro más austral con- firmado para la distribución del oso de anteojos en el Perú. Nuestros registros evidencian una continuidad en la distribución de esta especie en la vertiente oriental de la cordillera andina, desde el sur del Perú hasta el noroeste de Bolivia. Estos registros se hallan también muy próximos al Parque Nacional Bahuaja Sonene (PNBS, uno de los corredores de conservación más importantes en el mundo, y muestran la importancia de establecer estrategias de conservación tanto dentro como fuera de la zona de amortiguamiento del PNBS.

Tectonic geomorphology of large normal faults bounding the Cuzco rift basin within the southern Peruvian Andes

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Byers, C.; Mann, P.

2015-12-01

The Cuzco basin forms a 80-wide, relatively flat valley within the High Andes of southern Peru. This larger basin includes the regional capital of Cuzco and the Urubamba Valley, or "Sacred Valley of the Incas" favored by the Incas for its mild climate and broader expanses of less rugged and arable land. The valley is bounded on its northern edge by a 100-km-long and 10-km-wide zone of down-to-the-south systems of normal faults that separate the lower area of the down-dropped plateau of central Peru and the more elevated area of the Eastern Cordillera foldbelt that overthrusts the Amazon lowlands to the east. Previous workers have shown that the normal faults are dipslip with up to 600 m of measured displacements, reflect north-south extension, and have Holocene displacments with some linked to destructive, historical earthquakes. We have constructed topographic and structural cross sections across the entire area to demonstrate the normal fault on a the plateau peneplain. The footwall of the Eastern Cordillera, capped by snowcapped peaks in excess of 6 km, tilts a peneplain surface northward while the hanging wall of the Cuzco basin is radially arched. Erosion is accelerated along the trend of the normal fault zone. As the normal fault zone changes its strike from east-west to more more northwest-southeast, normal displacement decreases and is replaced by a left-lateral strike-slip component.

Up and down the blind alley: population divergence with scant gene flow in an endangered tropical lineage of Andean palms (Ceroxylon quindiuense clade: Ceroxyloideae).

Science.gov (United States)

Sanín, María José; Zapata, Patricia; Pintaud, Jean-Christophe; Galeano, Gloria; Bohórquez, Adriana; Tohme, Joseph; Hansen, Michael Møller

2017-02-10

Given the geographical complexity of the Andes, species distributions hold interesting information regarding the history of isolation and gene flow across geographic barriers and ecological gradients. Moreover, current threats to the region’s enormous plant diversity pose an additional challenge to the understanding of these patterns. We explored the geographic structure of genetic diversity within the Ceroxylon quindiuense species complex (wax palms) at a regional scale, using a model-based approach to disentangle the historical mechanisms by which these species have dispersed over a range encompassing 17° of latitude in the tropical Andes. A total of 10 microsatellite loci were cross-amplified in 8 populations of the 3 species comprising the C. quindiuense complex. Analyses performed include estimates of molecular diversity and genetic structure, testing for genetic bottlenecks and an evaluation of the colonization scenario under approximate Bayesian computation. We showed that there was a geographical diversity gradient reflecting the orogenetic pattern of the northern Andes and its end at the cordilleras facing the Caribbean Sea. A general pattern of diversity suggests that the cordilleras of Colombia have served as historical recipients of gene flow occurring only scantly along the northern Andes. We provided evidence of important isolation between the largest populations of this complex, suggesting that both historical constraints to dispersal but also current anthropogenic effects might explain the high levels of population structuring. We provide a list of advisable measures for conservation stakeholders.

Discovery of modern (post-1850 CE) lavas in south-central British Columbia, Canada: Origin from coal fires or intraplate volcanism?

Science.gov (United States)

Canil, Dante; Mihalynuk, Mitch; Lacourse, Terri

2018-01-01

We describe three unusual lavas in the Northern Cordillera in south-central British Columbia, Canada, occurring as spatter, scoria and blocks over small 400 m2 areas. The lavas coat and weld cobbles and pebbles in glacial till and are vesicular and glassy with microlites of clinopyroxene and plagioclase, and xenocrysts of quartz, feldspar or clinopyroxene. Chemically the lavas are basaltic trachyandesite (55-61 wt% SiO2) with trace element patterns similar to average British Columbia upper crust, except for having higher V and lower Zr, Hf, Nb, Th and U. Melting experiments and plagioclase-melt thermometry on the glasses, and phase equilibrium in simple systems, require liquidus temperatures of 1150-1300 °C. Interaction of the liquids with carbonaceous matter at low pressure formed Fe metal spherules and SiC. Radiocarbon ages of charcoal and dendrochronology show the lavas are modern, emplaced in the last 120 years. The similar bulk composition of these lavas to several other Quaternary-aged volcanic centers in the North American Cordillera, some of which show recent seismic activity, could suggest a possible tectonic origin, but the deposits are unusually small and show no central vent for emplacement. Conversely, the balance of evidence would suggest an origin from coal fires or hot gas venting, but is less consistent with the observed calc- and per-alkaline lava compositions, and the lack of known local coal-bearing strata as a heat source. Other anthropogenic origins for the lavas are considered less plausible.

Fitoplancton y aspectos físicos y químicos de la laguna de Chingaza en Cundinamarca, Colombia Fitoplancton y aspectos físicos y químicos de la laguna de Chingaza en Cundinamarca, Colombia

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Donato R. John Charles

1991-12-01

Full Text Available En la laguna de Chingaza (3265 m alt. Cordillera Oriental Colombiana, se realizaron muestreos de fitoplancton, mediciones de temperatura, oxígeno y parámetros físicos y químicos. La comunidad de fitoplancton comprende principalmente Desmidiaceae, Bacillariophyceae, y Cyanophyceae: La Desmidiacea Closterium sp. es la dominante durante la mayor parte del muestreo, pero en octubre (1989 la Cianofícea Oscillatoria sp. es la más significativa. En esta misma época la laguna presenta estratificación térmica y deficiencia de nitrógeno en sus aguas. Debido a los bajos valores en la relación nitrógeno/fósforo, conductividad, sólidos disueltos, acidez y ciertos organismos indicadores la laguna de chingaza es oligotrófica. At the Chingaza pond (3.265 m alt., located on the eastern Colombian cordillera, samples and measurements of temperature, oxygen, and physical-chemical parameters were taken. Phytoplankton community mainly consisted of Desmidiaceae, Bacillariophyceae, and Cyanophceae. Desmidiaceae species dominated in most samples, but in october (1989 Oscillatoria sp. (Cyanophyceae was the most abundant species. During the latter period the laguna exhibited strong thermal stratification and its inorganic nitrogen content was extremely low. It is believed that this is a good example of an oligotrophic pond given the presence of certain bioindicators, the low nitrogen/phosphorus ratio, conductivity, and quantity of suspended solids.

PWV, Temperature and Wind Statistics at Sites Suitable For mm and Sub-mm Wavelengths Astronomy

Science.gov (United States)

Otarola, Angel; Travouillon, Tony; De Breuck, Carlos; Radford, Simon; Matsushita, Satoki; Pérez-Beaupuits, Juan P.

2018-01-01

Atmospheric water vapor is the main limiting factor of atmospheric transparency in the mm and sub-mm wavelength spectral windows. Thus, dry sites are needed for the installation and successful operation of radio astronomy observatories exploiting those spectral windows. Other parameters that play an important role in the mechanical response of radio telescopes exposed to the environmental conditions are: temperature, and in particular temperature gradients that induce thermal deformation of mechanical structures, as well as wind magnitude that induce pointing jitter affecting this way the required accuracy in the ability to point to a cosmic source during the observations. Temperature and wind are variables of special consideration when planning the installation and operations of large aperture radio telescopes. This work summarizes the statistics of precipitable water vapor (PWV), temperature and wind monitored at sites by the costal mountain range, as well as on t he west slope of the Andes mountain range in the region of Antofagasta, Chile. This information could prove useful for the planning of the Atacama Large-Aperture Submm/mm Telescope (AtLast).

Leaching of copper concentrates with high arsenic content in chlorine-chloride media

International Nuclear Information System (INIS)

Herreros, O.; Fuentes, G.; Quiroz, R.; Vinals, J.

2003-01-01

This work reports the results of copper concentrates leaching which have high arsenic concepts (up to 2.5%). The treatments were carried out using chlorine that forms from sodium hypochlorite and sulphuric acid. The aim of this work is to obtain a solution having high copper content 4 to 6 g/l and 5 to 7 g/l free acid in order to submit it directly to a solvent extraction stage. In addition, this solution should have minimum content of arsenic and chloride ions. To carry out this investigation, an acrylic reactor was constructed where the leaching tests were made at constant temperature in a thermostatic bath under atmospheric pressure. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Typical variables were studied, such as leaching agent concentration, leaching time, pulp density and temperature among others. Some of the residues were analyzed by XRD and EPS. On the other hand, the solutions were analyzed by Atomic Absorption Spectroscopy. The results indicate solutions having the contents stated above can be obtained. (Author) 19 refs

Leaching of copper concentrates with high arsenic content in chlorine-chloride media; Lixiviacion de concentrados de cobre con alto contenido de arsenico en medio cloro-cloruro

Energy Technology Data Exchange (ETDEWEB)

Herreros, O.; Fuentes, G.; Quiroz, R.; Vinals, J.

2003-07-01

This work reports the results of copper concentrates leaching which have high arsenic concepts (up to 2.5%). The treatments were carried out using chlorine that forms from sodium hypochlorite and sulphuric acid. The aim of this work is to obtain a solution having high copper content 4 to 6 g/l and 5 to 7 g/l free acid in order to submit it directly to a solvent extraction stage. In addition, this solution should have minimum content of arsenic and chloride ions. To carry out this investigation, an acrylic reactor was constructed where the leaching tests were made at constant temperature in a thermostatic bath under atmospheric pressure. The concentrate samples were obtained from mineral processing plants from Antofagasta, Chile. Typical variables were studied, such as leaching agent concentration, leaching time, pulp density and temperature among others. Some of the residues were analyzed by XRD and EPS. On the other hand, the solutions were analyzed by Atomic Absorption Spectroscopy. The results indicate solutions having the contents stated above can be obtained. (Author) 19 refs.

Metazoan meiofauna within the oxygen-minimum zone off Chile: Results of the 2001-PUCK expedition

Science.gov (United States)

Veit-Köhler, Gritta; Gerdes, Dieter; Quiroga, Eduardo; Hebbeln, Dierk; Sellanes, Javier

2009-07-01

A quantitative study of metazoan meiofauna was carried out at continental shelf and slope stations affected by the oxygen-minimum zone in the eastern South Pacific off Chile. Densities of meiobenthos at the investigated stations off Antofagasta (22°S), Concepción (36°S), and Chiloé (42°S) ranged from 1282.1 to 8847.8 ind 10 cm -2. Oxygen deficiency led only to average abundances, despite higher food availability and freshness at the corresponding sites. Sediment organic carbon, chlorophyll- a, and phaeopigment contents were used as measures of the input from water-column primary production, which accumulated at the oxygen-minimum zone stations. The highest abundances were found at a station with an oxygen content of 0.79 mL L -1, which was slightly elevated from what is defined as oxygen minimum (0.5 mL L -1). The most oxygenated site yielded the lowest densities. Meiofauna assemblages became more diverse with increasing bottom-water oxygenation, whereas nematodes were the most abundant taxon at every station, followed by annelids, copepods, and nauplii.

Viticultura tropical a gran altitud. Condiciones y expresiones del terroir

OpenAIRE

Marco Quijano Rico

2009-01-01

Nuestro proyecto se inició en 1982 en la Loma de Puntalarga, entre 2500 y2600 metros de altitud, a 5,78 ºN y 72,98 ºW, en la cordillera oriental de los Andes. Las variedades más utilizadas actualmente son Pinot noir, Riesling y cruzamientos de Riesling x Silvaner. Desde 1984 se realizan trabajos de investigación sobre temas pertinentes. La baja latitud, la elevada altitud, el volumen de precipitación relativamente modesto y la transparencia del cielo, determinan el flujo de radiación solar in...

Variabilidad espacial y temporal de la temperatura del aire en la zona cafetera colombiana

OpenAIRE

Edna Paola Pérez Rendón; Víctor Hugo Ramírez Builes; Andrés Javier Peña Quiñones

2016-01-01

La zona cafetera colombiana está ubicada en- teramente en el hemisferio norte, entre los 1 y 11° grados de latitud, sobre la cordillera de los Andes. Esta condición (ecuatorial andina) ha hecho que se dé por sentado que la variación temporal de la temperatura es mínima y que por ello, en su mayor parte la variabilidad de este elemento es es- pacial, atribuible casi exclusivamente a los cambios en altura sobre el nivel del mar. En este estudio se exploran factores de variación al...

Potencial y plan exportador agua mineral BE

OpenAIRE

López Rodríguez, Diana Carolina; Rojas Isaza, Alejandro

2012-01-01

Agua Mineral BE Ltda es una empresa dedicada a la extracción, embotellado y comercialización de agua mineral colombiana, originada en las cordilleras de los Andes. Se caracteriza por ser de alta pureza y ser una bebida funcional, que trae beneficios adicionales a la salud por su composición de minerales, oligoelementos y electrolitos. Las condiciones de la empresa resultaron ser muy atractivas para desarrollar una investigación, por otro lado, el dueño y gerente general mostro gran interés en...

Planeamiento estratégico de la Provincia de Cajabamba

OpenAIRE

Leyva Ojeda, Ralph William; Manzanares Grados, Ruth Aracelis; Urbano Chunga, Elizabeth Gladys; Zeta Chulle, José de la Rosa

2017-01-01

La provincia de Cajabamba está ubicada en el extremo sur de la región de Cajamarca, conocida por su paradisiaca belleza de la Cordillera de los Andes del Perú, combinada con sus recursos mineros, productos agropecuarios y el comercio entre sus cuatro distritos y con otras regiones incluida la capital, presenta un alto grado de pobreza y pobreza extrema en su población, además de un bajo número de asistentes a educación secundaria, carreras técnicas y universitarios, debido a un...

Neoelmis guarani Shepard & Barr, a sexually dimorphic new species from Paraguay (Insecta: Coleoptera: Elmidae: Elminae).

Science.gov (United States)

Shepard, William D; Barr, Cheryl B

2016-02-22

Neoelmis guarani new species is described and illustrated from specimens collected in streams of the Cordillera de los Altos, southeast of Asunción and near the towns of Piribebuy and Chololó, Paraguay. Males and females of this species exhibit strong secondary sexual dimorphism not found in other known species of Neoelmis. Males have striking modifications of the pro- and mesothoracic legs and bear a pair of ventrally projecting processes on both the mesoventrite and the second abdominal ventrite. Females have the elytra modified with a pair of dorsal projections.

Una nueva especie de bolitoglossa (caudata: plethodontidae) de las selvas del magdalena medio en colombia

OpenAIRE

Acosta Galvis, Andrés R.; Restrepo, Ana E.

2010-01-01

Se describe una nueva especie del genero Bolitoglossa del grupo alfa (sensu Wake & Lynch, 1976) denominada Bolitoglossa lozanoi de las selvas húmedas relictuales del valle del Río Magdalena en La Cordillera Central de Colombia (loe. typ.: Río La Miel, Mpio. La Victoria, Departamento de Caldas, 500 m.s.n.m.); la nueva especie es reconocible por su cuerpo robusto, las palmeaduras manuales y pediales extensas, su patrón cromático ventral café con punteaduras café más oscuras y crema, ojos no pro...

Sedimentología y evolución paleogeográfica de la cubeta de Las Hoyas (Cretácico inferior, Serranía de Cuenca)

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Fregenal-Martínez, M. A.; Meléndez, N.

1993-01-01

[ES] La cubeta de Las Hoyas (Serranía de Cuenca, Cordillera Ibérica) sufrió un relleno sedimentario complejo durante el Cretácico inferior. En un contexto de rift intracontinental, la cubeta de Las Hoyas se encontraba localizada sobre un bloque subsidente controlado por directrices tectónicas ONO-ESE y NO-SE. La variación a lo largo del tiempo del equilibrio entre la tasa de sedimentación y la tectónica sinsedimentaria activa, en interacción con una serie de factores intra y...

Caracterización de dos sistemas de abanicos aluviales húmedos en el Terciario de la Depresión Intermedia (Cuenca-Guadalajara)

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de TORRES, T.; ZAPATA, J. L.

1986-01-01

En este trabajo se comparan las características de dos abanicos aluviales del Primer Ciclo Neógeno (Ageniense superior-Aragoniense inferior) de la Depresion Intermedia. Estos abanicos tienen una serie de características comunes como: área fuente en la Cordillera Ibérica, períodos alternantes de funcinamiento de canales de baja y alta sinuosidad e interdigitación distal con depósitos lacustres de yesos bioturbados. Se diferencian en la orientación de paleocorrientes y presencia en uno de ellos...