Hydrological response in catchments whit debris covered glaciers in the semi-arid Andes, Chile

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Caro, A.; McPhee, J.; MacDonell, S.; Pellicciotti, F.; Ayala, A.

2016-12-01

Glaciers in the semi-arid Andes Cordillera in Chile have shrank rapidly during the 20th century. Negative mass balance contributes to increase the surface area of debris-covered glaciers. Recent research in Chile suggests that contributions from glaciers to summer season river flow in dry years is very important, however hydrological processes determining the glacier contribution are still poorly understood in the region. This work seeks to determine appropriate parameters for the simulation of melt volume in two watersheds dominated by debris-covered glaciers, in order to understand its variability in time and space, in the area with the largest population in Chile. The hydrological simulation is performed for the Tapado (30°S) and Pirámide (33ºS) glaciers, which can be defined as cold and temperate respectively. To simulate the hydrological behaviour we adopt the physically-based TOPographic Kinematic wave APproximation model (TOPKAPI-ETH). The hydrometeorological records necessary model runs have been collected through fieldwork from 2013 to 2015. Regarding the calibration of the model parameters melting ETI, its observed that the value for TF in Pirámide is a third of the value for Tapado glacier, while SRF is half in Tapado regarding to Pirámide. The runoff in the glaciers, the constant snow and ice storage are higher in Tapado regarding Pirámide. Results show a contribution of glacial outflow to runoff during 2015 of 55% in Tapado and 77% in Pirámide, with maximum contributions between January and March in Tapado and Pirámide between November and March, presenting the relevance of the permanence of snow cover during spring and shelter that provides debris-covered in reducing the melting glacier. The results have allowed to know the relevance of the glacier contribution to mountain streams, allowing to know the calibration parameters most relevant in the hydrology balance of glacier basins in the Andes.

Impact of Santiago de Chile urban atmospheric pollution on anthropogenic trace elements enrichment in snow precipitation at Cerro Colorado, Central Andes

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Cereceda-Balic, F.; Palomo-Marín, M. R.; Bernalte, E.; Vidal, V.; Christie, J.; Fadic, X.; Guevara, J. L.; Miro, C.; Pinilla Gil, E.

2012-02-01

Seasonal snow precipitation in the Andes mountain range is evaluated as an environmental indicator of the composition of atmospheric emissions in Santiago de Chile metropolitan area, by measuring a set of representative trace elements in snow samples by ICP-MS. Three late winter sampling campaigns (2003, 2008 and 2009) were conducted in three sampling areas around Cerro Colorado, a Central Andes mountain range sector NE of Santiago (36 km). Nevados de Chillán, a sector in The Andes located about 500 km south from the metropolitan area, was selected as a reference area. The experimental results at Cerro Colorado and Nevados de Chillán were compared with previously published data of fresh snow from remote and urban background sites. High snow concentrations of a range of anthropogenic marker elements were found at Cerro Colorado, probably derived from Santiago urban aerosol transport and deposition combined with the effect of mining and smelting activities in the area, whereas Nevados de Chillán levels roughly correspond to urban background areas. Enhanced concentrations in surface snow respect to deeper samples are discussed. Significant differences found between the 2003, 2008 and 2009 anthropogenic source markers profiles at Cerro Colorado sampling points were correlated with changes in emission sources at the city. The preliminary results obtained in this study, the first of this kind in the southern hemisphere, show promising use of snow precipitation in the Central Andes as a suitable matrix for receptor model studies aimed at identifying and quantifying pollution sources in Santiago de Chile.

Craniofacial chronological microdifferentiation of human prehistoric populations of the Azapa valley, northern Chile Microdiferenciación cronológica craneofacial de poblaciones humanas prehistóricas del Valle de Azapa, norte de Chile

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FRANCISCO ROTHHAMMER

2002-03-01

Full Text Available Archeological evidence suggest that the cultural developments occurred in the highlands around lake Titicaca in the Central Andes, exerted influence on the cultural elaborations of the human groups that peopled the valley of Azapa, close to the city of Arica, and the Pacific coast of northern Chile. In this communication we show by means of a distance analysis, that a craniofacial differentiation accompanied the process of cultural evolution in the valley. The biological influence of Tiwanaku is partially reflected in craniofacial morphology, providing preliminary evidence that cultural changes were associated to intermittent gene flow from the highlands, specially during the Alto Ramírez and San Miguel phasesLos desarrollos culturales ocurridos en el altiplano en el área circumtiticaca en los Andes centrales, ejercieron influencia sobre las elaboraciones culturales de los grupos humanos que poblaban el Valle de Azapa cercano a la ciudad de Arica y la costa del norte de Chile. En esta comunicación presentamos un análisis de distancias que demostró que una diferenciación craniofacial acompaño en el valle el proceso de evolución cultural. La influencia biológica de Tiwanaku se refleja parcialmente en la morfología craniofacial, proporcionando evidencia preliminar de que los cambios culturales en el valle se realizaron acompañados de flujo génico intermitente desde el altiplano, especialmente durante las fases Alto Ramírez y San Miguel

Glaciation in the Andes during the Lateglacial and Holocene

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Rodbell, Donald T.; Smith, Jacqueline A.; Mark, Bryan G.

2009-10-01

advances in the interval between 1.0 and 2.5 ka. Moraines that correlate with the LIA of the Northern Hemisphere are seen in all presently glacierized mountain ranges; most of these date to within the past 450 years. Outboard of these moraines in many regions are moraines of a slightly more extensive advance that occurred several hundred years prior to the onset of the LIA. Priorities for future work include filling in several prominent spatial gaps in the distribution of chronologic studies. For the Lateglacial these gaps include the arid regions of northern Chile and Argentina, the southern Peruvian Andes between 11.5°and 13.5°S, and the Andes of northern Peru and southern Ecuador between 3° and 9°S. Areas in need of better representation in regional datasets of Holocene glaciation include all of the Andes north of the Equator. Specific chronologic priorities include the need for close bracketing radiocarbon ages for purported Early and Mid-Holocene moraines, and the increased application of cosmogenic radionuclide dating to Lateglacial and Early Holocene moraines that are already constrained by maximum-limiting radiocarbon ages.

High altitude C4 grasslands in the northern Andes: relicts from glacial conditions?

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Boom, A.; Mora, G.; Cleef, A.M.; Hooghiemstra, H.

2001-01-01

The altitudinal vegetation distribution in the northern Andes during glacial time differed from the present-day conditions as a result of temperature and precipitation change. New evidence indicate that as a response to a reduced atmospheric partial CO2 pressure (pCO2), the competitive balance

Bofedales: high altitude peatlands of the central Andes Bofedales: turberas de alta montaña de los Andes centrales

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FRANCISCO A SQUEO

2006-06-01

Full Text Available There is an exceptional group of alpine peatlands in the world situated in the arid grasslands of the central Andes. The peatlands in northern Chile occur in the most arid part of their range. Members of the Juncaceae are the primary peat-forming plant species. Fresh and mildly saline groundwaters originate from glaciers, snowmelt and rain are the water sources for the northern Chile peatlands. Paleoecological investigations suggest that some peatlands are recent features of the landscape having developed within the last three thousand years or less. These peatlands are unique, extremely fragile water features sensitive to climate changes and human disturbances such as regional mining activity. Much more work is required to develop scientifically based sound management and conservation programs for the rare plants and animals that live in them and to ensure the future livelihoods of the indigenous peoples who depend on themExiste un grupo excepcional de turberas (bofedales de alta montaña en el mundo situados en la estepa árida de los Andes centrales. Los bofedales en el norte de Chile están presentes en la parte más árida de su rango. Las principales especies de plantas responsables de la formación de turba corresponden a miembros de Juncaceae. El agua fresca y medianamente salina de los bofedales proviene de agua subterránea asociada a riachuelos proveniente de glaciares, derretimiento de nieve y lluvia. Investigaciones paleoecológicas sugieren que algunos bofedales son integrantes recientes del paisaje, habiéndose desarrollado durante los últimos tres mil años o menos. Estos bofedales son entidades únicas, extremadamente frágiles por su dependencia del agua, sensibles a los cambios climáticos y vulnerables a la alteración humana tal como la actividad minera en la región. Se requiere mucho más trabajo para desarrollar programas de manejo y conservación, con sólidas bases científicas, de las plantas y animales que viven en

Angiosperm flora and biogeography of the páramo region of Colombia, northern Andes

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Londoño, C.; Cleef, A.; Madriñan, S.

2014-01-01

Páramo is the neotropical high elevation ecosystem in the northern Andes and Central America consisting of multiple dissected open areas above 3000 m a.s.l. Complex evolutionary processes that occurred within these ecosystems gave rise to a unique tropical Andean flora. Previous phytogeographical

Use of high-resolution satellite images for detection of geological structures related to Central Andes geothermal field, Chile.

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Benavides-Rivas, C. L.; Soto-Pinto, C. A.; Arellano-Baeza, A. A.

2014-12-01

Central valley and the border with Argentina in the center, and in the fault system Liquiñe-Ofqui in the South of the country. High resolution images from the LANDSAT 8 satellite have been used to delineate the geological structures related to the potential geothermal reservoirs located at the northern end of the Southern Volcanic Zone of Chile. It was done by applying the lineament extraction technique, using the ADALGEO software, developed by [Soto et al., 2013]. These structures have been compared with the distribution of main geological structures obtained in the field. It was found that the lineament density increases in the areas of the major heat flux indicating that the lineament analysis could be a power tool for the detection of faults and joint zones associated to the geothermal fields. A lineament is generally defined as a straight or slightly curved feature in the landscape visible satellite image as an aligned sequence of pixel intensity contrast compared to the background. The system features extracted from satellite images is not identical to the geological lineaments that are generally determined by ground surveys, however, generally reflects the structure of faults and fractures in the crust. A temporal sequence of eight Landsat multispectral images of Central Andes geothermal field, located in VI region de Chile, was used to study changes in the configuration of the lineaments during 2011. The presence of minerals with silicification, epidotization, and albitization, which are typical for geothrmal reservoirs, was also identified, using their spectral characteristics, and subsequently corroborated in the field. Both lineament analysis and spectral analysis gave similar location of the reservoir, which increases reliability of the results.

New GPS velocity field in the northern Andes (Peru - Ecuador - Colombia): heterogeneous locking along the subduction, northeastwards motion of the Northern Andes

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Nocquet, J.; Mothes, P. A.; Villegas Lanza, J.; Chlieh, M.; Jarrin, P.; Vallée, M.; Tavera, H.; Ruiz, G.; Regnier, M.; Rolandone, F.

2010-12-01

Rapid subduction of the Nazca plate beneath the northen Andes margin (~6 cm/yr) results in two different processes: (1) elastic stress is accumulating along the Nazca/South American plate interface which is responsible for one of the largest megathrust earthquake sequences during the last century. The 500-km-long rupture zone of the 1906 (Mw= 8.8) event was partially reactivated by three events from the 1942 (Mw = 7.8), 1958 (Mw = 7.7), to the 1979 (Mw = 8.2). However, south of latitude 1°S, no M>8 earthquake has been reported in the last three centuries, suggesting that this area is slipping aseismically (2) permanent deformation causes opening of the Gulf of Guayaquil, with northeastwards motion of the Northern Andean Block (NAB). We present a new GPS velocity field covering the northern Andes from south of the Gulf of Guayaquil to the Caribbean plate. Our velocity field includes new continuously-recording GPS stations installed along the Ecuadorian coast, together with campaign sites observed since 1994 in the CASA project (Kellogg et al., 1989). We first estimate the long-term kinematics of the NAB in a joint inversion including GPS data, earthquake slip vectors, and quaternary slip rates on major faults. The inversion provides an Euler pole located at long. -107.8°E, lat. 36.2°N, 0.091°/Ma and indicates little internal deformation of the NAB (wrms=1.2 mm/yr). As a consequence, 30% of the obliquity of the Nazca/South America motion is accommodated by transcurrent to transpressive motion along the eastern boundary of the NAB. Residual velocities with respect to the NAB are then modeled in terms Models indicate a patchwork of highly coupled asperities encompassed by aseismic patches over the area of rupture of the M~8.8 1906 earthquake. Very low coupling is found along the southern Ecuadorian and northern Peru subduction.

Classification of debris-covered glaciers and rock glaciers in the Andes of central Chile

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Janke, Jason R.; Bellisario, Antonio C.; Ferrando, Francisco A.

2015-07-01

In the Dry Andes of Chile (17 to 35° S), debris-covered glaciers and rock glaciers are differentiated from true glaciers based on the percentage of surface debris cover, thickness of surface debris, and ice content. Internal ice is preserved by an insulating cover of thick debris, which acts as a storage reservoir to release water during the summer and early fall. These landforms are more numerous than glaciers in the central Andes; however, the existing legislation only recognizes uncovered or semicovered glaciers as a water resource. Glaciers, debris-covered glaciers, and rock glaciers are being altered or removed by mining operations to extract valuable minerals from the mountains. In addition, agricultural expansion and population growth in this region have placed additional demands on water resources. In a warmer climate, as glaciers recede and seasonal water availability becomes condensed over the course of a snowmelt season, rock glaciers and debris-covered glaciers contribute a larger component of base flow to rivers and streams. As a result, identifying and locating these features to implement sustainable regional planning for water resources is important. The objective of this study is to develop a classification system to identify debris-covered glaciers and rock glaciers based on the interpretation of satellite imagery and aerial photographs. The classification system is linked to field observations and measurements of ice content. Debris-covered glaciers have three subclasses: surface coverage of semi (class 1) and fully covered (class 2) glaciers differentiates the first two forms, whereas debris thickness is critical for class 3 when glaciers become buried with more than 3 m of surface debris. Based on field observations, the amount of ice decreases from more than 85%, to 65-85%, to 45-65% for semi, fully, and buried debris-covered glaciers, respectively. Rock glaciers are characterized by three stages. Class 4 rock glaciers have pronounced

The Bulimulidae (Mollusca: Pulmonata) from the Región de Atacama, northern Chile.

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Araya, Juan Francisco

2015-01-01

The bulimulid genus Bostryx Troschel, 1847 is the most species-rich genus of land snails found in Chile, with the majority of its species found only in the northern part of the country, usually in arid coastal zones. This genus has been sparsely studied in Chile and there is little information on their distribution, diversity or ecology. Here, for the first time, a formal analysis of the diversity of bulimulids in the Región de Atacama, northern Chile, is reported. Of the seventeen species recorded for the area, most of them were efectively found in the field collections and one record was based on literature. Five taxa are described as new: Bostryx ancavilorum sp. nov., Bostryx breurei sp. nov., Bostryx calderaensis sp. nov., Bostryx ireneae sp. nov. and Bostryx valdovinosi sp. nov., and the known geographic distribution of seven species is extended. Results reveal that the Región de Atacama is the richest region in terrestrial snails in Chile, after the Juan Fernández Archipelago. All of the terrestrial molluscan species occurring in the area are endemic to Chile, most of them with restricted geographic distributions along the coastal zones, and none of them are currently protected by law. Further sampling in northern Chile will probably reveal more snail species to be discovered and described.

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.

Air temperature change in the northern and southern tropical Andes linked to North-Atlantic stadials and Greenland interstadials

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Urrego, Dunia H.; Hooghiemstra, Henry

2016-04-01

We use eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the signature of millennial-scale climate variability during the last 30,000 years, in particular the Younger Dryas (YD), Heinrich stadials (HS) and Greenland interstadials (GI). We identify rapid responses of the vegetation to millennial-scale climate variability in the tropical Andes. The signature of HS and the YD are generally recorded as downslope migrations of the upper forest line (UFL), and are likely linked to air temperature cooling. The GI1 signal is overall comparable between northern and southern records and indicates upslope UFL migrations and warming in the tropical Andes. Our marker for lake level changes indicates a north to south difference that could be related to moisture availability. The direction of air temperature change recorded by the Andean vegetation is consistent with millennial-scale cryosphere and sea surface temperature records from the American tropics, but suggests a potential difference between the magnitude of temperature change in the ocean and the atmosphere.

International Uranium Resources Evaluation Project (IUREP) national favourability studies: Chile

International Nuclear Information System (INIS)

1977-08-01

Chile has an area of 740,760 square kilometers. The capital is Santiago. The country is 4,183 km. long and ranges from 22.5 to about 354 km. in width. Its chief topographic features para]lei each other - the Coastal Range, Andes Mountains and Central Valley. The Coastal Range rises to 2,130 meters in the north, but averages from 610 to 700 meters high generally. The range plunges into the Pacific Ocean far south of Valparaiso and reappears in the southern archipelagic islands. The Andes extend along nearly the entire length of Chile and contain 100 volcanoes. Andean peaks range mostly from 3,000 to 6,700 meters in elevation. In southern Chile the Andes are lower, and contain about a dozen major lakes. The mountains disappear in Chilean Patagonia, but reappear at Cape Horn. The Central Valley lies between the Coastal Range and the Andes, being best defined in the midland region as a 64 to 72 km sloping plain. It is the Chilean heartland with three-quarters of the country's population. Salt basins are found over much of northern Chile in the very arid desert, while the region south of the Gulf of Reloncavi consists of unpopulated islands, fjords, channels and heavily forested mountains. The Strait of Magellan, the Tierra del Fuego archipelago and a flat grassland area make up the extreme southern end of the country. Much of Chile is subject to flash floods, earthquakes, volcanic eruptions, landslides and avalanches. In September 1976 the Comision Chilena de Energia Nuclear (CCEN) was given exclusive rights to negotiate contracts with private companies for the exploration, development and mining of uranium and other radioactive minerals. The new law provides the CCEN with considerable flexibility in the terms of the contracts. Pre-964 owners of uranium deposits may reach agreements with foreign companies to mine the uranium, but since 1964 all uranium has belonged to the state. Uranium produced in the country can only be exported after Chile's needs have been met. The

Spatial coincidence and similar geochemistry of Late Triassic and Eocene-Oligocene magmatism in the Andes of northern Chile: evidence from the MMH porphyry type Cu-Mo deposit, Chuquicamata District

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Zentilli, Marcos; Maksaev, Victor; Boric, Ricardo; Wilson, Jessica

2018-04-01

The MMH porphyry type copper-molybdenum deposit in northern Chile is the newest mine in the Chuquicamata District, one of largest copper concentrations on Earth. Mineralized Eocene-Oligocene porphyry intrusions are hosted by essentially barren Triassic granodiorites. Despite a century of exploitation, geologists still have problems in the mine distinguishing the Triassic granodiorite from the most important ore-carrying Eocene porphyries in the district. To resolve the problem, internally consistent high-quality geochemical analyses of the Triassic and Tertiary intrusives were carried out: explaining the confusion, they show that the rock units in question are nearly identical in composition and thus respond equally to hydrothermal alteration. In detail, the only difference in terms of chemical composition is that the main Eocene-Oligocene porphyries carry relatively less Fe and Ni. Unexpectedly, the mineralized Eocene-Oligocene porphyries have consistently less U and Th than other Tertiary intrusions in the district, a characteristic that may be valuable in exploration. The supergiant copper-molybdenum deposits in the Central Andes were formed within a narrow interval between 45 and 31 Ma, close to 7% of the 200 My duration of "Andean" magmatism, which resulted from subduction of oceanic lithosphere under South America since the Jurassic. Although recent work has shown that subduction was active on the margin since Paleozoic times, pre-Andean (pre-Jurassic) "Gondwanan" magmatism is often described as being very different, having involved crustal melting and the generation of massive peraluminous rhyolites and granites. This study shows that the indistinguishable Late Triassic and Eocene-Oligocene intrusions occupy the same narrow NS geographic belt in northern Chile. If it is accepted that magma character may determine the potential to generate economic Cu-Mo deposits, then Late Triassic volcano-plutonic centres in the same location in the South American margin

Central Chile

Science.gov (United States)

2002-01-01

The beginning of spring in central Chile looked like this to SeaWiFS. The snow-covered Andes mark the country's eastern border, and phytoplankton blooms and river sediment plumes fill the waters off its west coast. A large eddy due west of Concepcion is highlighted by the phytoplankton it contains.

Social Well-Being Among Colombian and Peruvian Immigrants in Northern Chile.

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Urzúa Morales, Alfonso; Delgado-Valencia, Eric; Rojas-Ballesteros, Mariela; Caqueo-Urízar, Alejandra

2017-10-01

In recent years, northern Chile has received a large number of immigrants attracted mainly by mining and related services. The last population census revealed that 70.5 % of foreigners in Chile came from South America, and were mainly Peruvians (30.5 %), Argentines (16.8 %), and Colombians (8.1 %). The aim of this cross-sectional study is to describe the social well-being levels reported by Colombian and Peruvian immigrants in northern Chile, as well as their connection to socio-demographic and relational factors. The Spanish version of the Scale of Social Well-being (Keyes in Soc Psychol Q 61:121-140, 1998) was administered to 431 men and women over 18 years old, with a minimum residence of 6 months in the city of Antofagasta. The highest-rated aspect was Social Contribution, and the lowest-rated aspect was Social Acceptance. The relational variables that show statistically significant differences in both populations relate to who the subject lives with, the degree of contact that the subject has with people from Chile, and the subject's relationship status. There are no differences that indicate a higher level of social well-being in one population more than the other; however, it appears that the Peruvian population has a greater perception of Social Coherence, while Colombians show a greater perception of Social Contribution.

Sr and Nd isotopic and trace element compositions of Quaternary volcanic centers of the Southern Andes

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Futa, K.; Stern, C.R.

1988-01-01

Isotopic compositions of samples from six Quaternary volcanoes located in the northern and southern extremities of the Southern Volcanic Zone (SVZ, 33-46??S) of the Andes and from four centers in the Austral Volcanic Zone (AVZ, 49-54??S) range for 87Sr 86Sr from 0.70280 to 0.70591 and for 143Nd 144Nd from 0.51314 to 0.51255. The ranges are significantly greater than previously reported from the southern Andes but are different from the isotopic compositions of volcanoes in the central and northern Andes. Basalts and basaltic andesites from three centers just north of the Chile Rise-Trench triple junction have 87Sr 86Sr, 143Nd 144Nd, La Yb, Ba La, and Hf Lu that lie within the relatively restricted ranges of the basic magmas erupted from the volcanic centers as far north as 35??S in the SVZ of the Andes. The trace element and Sr and Nd isotopic characteristics of these magmas may be explained by source region contamination of subarc asthenosphere, with contaminants derived from subducted pelagic sediments and seawater-altered basalts by dehydration of subducted oceanic lithosphere. In the northern extremity of the SVZ between 33?? and 34??S, basaltic andesites and andesites have higher 87Sr 86Sr, Rb Cs, and Hf Lu, and lower 143Nd 144Nd than basalts and basaltic andesites erupted farther south in the SVZ, which suggests involvement of components derived from the continental crust. In the AVZ, the most primitive sample, high-Mg andesite from the southernmost volcanic center in the Andes (54??S) has Sr and Nd isotopic compositions and K Rb and Ba La similar to MORB. The high La Yb of this sample suggests formation by small degrees of partial melting of subducted MORB with garnet as a residue. Samples from centers farther north in the AVZ show a regionally regular northward increase in SiO2, K2O, Rb, Ba, Ba La, and 87Sr 86Sr and decrease in MgO, Sr, K Rb, Rb Cs, and 143Nd 144Nd, suggesting increasingly greater degrees of fractional crystallization and associated intra

Triassic volcanic units in coastal region of Antofagasta, northern Chile

International Nuclear Information System (INIS)

Basso, M.; Cortes, J.A.; Marinovic, N

2001-01-01

U-Pb geochronological evidence of a Middle to Late Triassic volcanic event was found in the coastal region of Antofagasta, northern Chile (23 o -23 o 30 ). Two new ages were obtained from rhyolitic tuffs and an associated dome, which have classically been attributed to the Jurassic La Negra Formation (au)

Late cenozoic tectonic and geomorphic evolution of the Patagonian Andes between 42oS and 52oS, southern Chile assessed using fission-track thermochronology

International Nuclear Information System (INIS)

Thomson, S.N; Herve, F; Stockhert, B.; Brix, M.R.; Adriasola, A

2001-01-01

Fission-track (FT) analysis has been applied in the Patagonian Andes of southern Chile to assess the late Cenozoic geomorphic and tectonic response of the overriding plate to subduction of the Chile rise active oceanic spreading centre (Thomson et al., 2001). The timing and nature of tectonic uplift and denudation along the southern parts of the major transpression intra-arc Liquine-Ofqui fault (LOF) system have also been investigated (Thomson, 2001, submitted). Results from 130 FT ages (72 zircon and 58 apatite ages) and 39 apatite track length measurements reveal initiation of rapid cooling and denudation at ca. 30 Ma at the western margin of southern continental South America. This was followed by a ca. 200km eastward migration of the locus of maximum denudation to the position of the present day topographic divide between ca. 30 Ma and ca. 12 to 10 Ma. East of the Andean divide less than 3 km of denudation has occurred since the Late Cretaceous. Enhanced denudation is interpreted to be the result of increased tectonic uplift driven by a large increase in convergence rates at ca. 28 to 26 Ma that triggered orographically enhanced precipitation on the west-side of the Patagonian Andes allowing increased erosion by fluvial incision and mass transport processes. The eastward migration of the locus of maximum denudation can be related to either coeval eastward migration of the retro-arc deformation front, the effects of subduction erosion in the overriding plate at the Peru-Chile trench or shallowing of the angle of subduction. Away from the influence of the LOF the process of spreading centre subduction and collision itself coincides with an overall slow-down in denudation rates in the overriding plate most likely caused by a major reduction in the main tectonic force driving tectonic uplift in the upper plate to subduction. In contrast to the Andes south of ca. 46 o S, increased cooling and denudation related to transpression induced rock uplift and erosion along

ANDES: An Underground Laboratory in South America

Science.gov (United States)

Dib, Claudio O.

ANDES (Agua Negra Deep Experiment Site) is an underground laboratory, proposed to be built inside the Agua Negra road tunnel that will connect Chile (IV Region) with Argentina (San Juan Province) under the Andes Mountains. The Laboratory will be 1750 meters under the rock, becoming the 3rd deepest underground laboratory of this kind in the world, and the first in the Southern Hemisphere. ANDES will be an international Laboratory, managed by a Latin American consortium. The laboratory will host experiments in Particle and Astroparticle Physics, such as Neutrino and Dark Matter searches, Seismology, Geology, Geophysics and Biology. It will also be used for the development of low background instrumentation and related services. Here we present the general features of the proposed laboratory, the current status of the proposal and some of its opportunities for science.

Coupled geohazards at Southern Andes (Copahue-Lanín volcanoes): Chile's GEO supersite proposal

Science.gov (United States)

Lara, Luis E.; Cordova, Loreto

2017-04-01

Southern Andes are a young and active mountain belt where volcanism and tectonic processes (and those related to the hydrometeorological conditions controlled by this geological setting) pose a significant threat to the growing communities nearby. This proposal focus on a ca. 200 km long segment of the Southern Andes where 9 stratovolcanoes and 2 distributed volcanic fields are located, just along a tectonic corridor defined by the northern segment of the Liquiñe-Ofqui Faul System (LOFS), a long-lived active strike-slip fault running for 1200 km. Volcanoes in this area take part of the central province of the Andean Southern Volcanic Zone (37-41°S), particularly the northermost portion that is limited at the south by an Andean tranverse fault (Lanalhue Fault, which define the Villarrica-Lanin volcanic chain) and run along the horse-tail array of the LOFS to the north. Most of the stravolcanoes are atop of the LOFS main branch with only 3 exceptions (Callaqui, Tolhuaca and Lanín) 15-20 km away, but related to transverse faults. Hazards in the segment derive from the activity of some of the most active volcanoes in South America (e.g., Villarrica, Llaima), others with long-lasting weak activity (e.g., Copahue) or some volcanoes with low frequency but high magnitude eruptions in the geological record. Only since the beggining of the 20th century 80 eruptions have been recorded in this area. In addition, activity of the LOFS has been detected prior to some eruptions and coeval with some others (e.g., Lonquimay 1989). A strong two-way coupling between tectonics and volcanism has been proposed for the segment but only recently detected by geophysical techniques or numerical modelling. Tectonic triggered landslides are frequent in this region together with debris flows at erupting ice-covered volcanoes or stream headed at high altitude basins. The latter scenario seems to be worst at present because of global climate change. Ground-based monitoring networks for both

On the generation of coastal lows in central Chile

International Nuclear Information System (INIS)

Rutllant, J.

1994-07-01

Previous studies of the coastal-low occurrences in central Chile have been aimed at the formulation of a conceptual model to explain observed features in connection with applied studies. The most prominent weather pattern associated with CL occurrences, (type A), coincides with the onset of a warm, middle-troposphere ridge over central Chile, and a surface high over northern Argentina. The synoptic forcing of the low is related to weak frontal disturbances that travel equatorwards. They result in a thickening of the marine layer that becomes blocked by the coastal escarpment, at the time of the onset of the ridge aloft. The blocking of the stable air above the subsidence inversion by the Andes is also hypothesized. The analysis of the subsidence inversion, the geometry of the coastal and Andes mountain ranges, and a scale analysis of the non-dimensional governing equations for the generation of the coastal lows, following the approach of Reason and Steyn (1990); leads to the conclusion that both blocking actions are strong and persistent in central Chile. An interactive mechanism between the upper and lower blocking effects is postulated to explain the cyclonic vorticity and the initial steering of the coastal lows. The scale analysis of the governing equations for the propagation stage of the low suggests that, departing for the South African case, non-linearity is important here, and that solitary Kelvin waves could be expected. Theoretical phase propagation speeds and Rossby radii are found to range between 8 and 15 m s-1 and 100-250 km, respectively. The importance of strong southerly winds ahead of the low and weak winds at its trailing edge is also stressed, as another major departure from the coastal-low behaviour elsewhere. (author). 17 refs, 4 figs, 4 tabs

Protection of Northern Chile as an ICOMOS/IAU ``Window to the Universe''

Science.gov (United States)

Smith, Malcolm G.

2015-03-01

Over the last two decades, La Serena's population has increased by about 70 percent. A site description of the AURA Observatory in Chile as a ``Window to the Universe`` is now available on the recently-launched UNESCO-IAU Astronomical Heritage Web Portal, www.astronomicalheritage.net This can serve as an example of possible material for the Chilean authorities, should they wish to propose the dark skies over much of northern Chile for protection as a World Scientific Heritage site. Some of the steps involved are discussed briefly here.

Geothermal Potential Evaluation for Northern Chile and Suggestions for New Energy Plans

Directory of Open Access Journals (Sweden)

Monia Procesi

2014-08-01

Full Text Available Chile is a country rich in natural resources, and it is the world’s largest producer and exporter of copper. Mining is the main industry and is an essential part of the Chilean economy, but the country has limited indigenous fossil fuels—over 90% of the country’s fossil fuels must be imported. The electricity market in Chile comprises two main independent systems: the Northern Interconnected Power Grid (SING and the Central Interconnected Power Grid (SIC. Currently, the primary Chilean energy source is imported fossil fuels, whereas hydropower represents the main indigenous source. Other renewables such as wind, solar, biomass and geothermics are as yet poorly developed. Specifically, geothermal energy has not been exploited in Chile, but among all renewables it has the greatest potential. The transition from thermal power plants to renewable energy power plants is an important target for the Chilean Government in order to reduce dependence on imported fossil fuels. In this framework, the proposed study presents an evaluation of the geothermal potential for northern Chile in terms of power generation. The El Tatio, Surire, Puchuldiza, Orriputunco-Olca and Apacheta geothermal fields are considered for the analysis. The estimated electrical power is approximately 1300 MWe, and the energy supply is 10,200 GWh/year. This means that more than 30% of the SING energy could be provided from geothermal energy, reducing the dependence on imported fossil fuels, saving 8 Mton/year of CO2 and supplying the mining industry, which is Chile’s primary energy user.

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.

Natural gas across the Andes : a case study of an international business venture

Energy Technology Data Exchange (ETDEWEB)

Figueroa, E.B.; Smith, B.

2002-07-01

This book describes the challenges and complexities of constructing the GasAndes pipeline from Argentinian gas fields across the Andes to Santiago in Chile. The project was a joint international effort between Canada's NOVA Corporation, Chile's Gasco and Gener, and Argentina's Compania General de Combustibles and Techint Compania Tecnica Internacional. The book relates how NOVA Gas International, together with its partners, accomplished the task of constructing the first major natural gas pipeline across the Andes mountains despite significant challenges such as steep mountain slopes, many river crossings, high altitude, high winds and bitter cold. It describes how the partnership developed and how political and socio-economic issues were dealt with. It demonstrates how business practices were modified to deal with local conditions and to ensure that the fragile environment of the Andean meadows was protected. It also describes how the builders of the pipeline addressed the concerns of communities along the pipeline route. The pipeline was constructed at a time when democracy was returning and market economies were shifting from a reduced role of government in the energy sector. The 463 km GasAndes pipeline has been in operation since August 7, 1997. refs., tabs., figs.

Molecular phylogeography of the Andean alpine plant, Gunnera magellanica

Science.gov (United States)

Shimizu, M.; Fujii, N.; Ito, M.; Asakawa, T.; Nishida, H.; Suyama, C.; Ueda, K.

2015-12-01

To clarify the evolutionary history of Gunnera magellanica (Gunneraceae), an alpine plant of the Andes mountains, we performed molecular phylogeographic analyses based on the sequences of an internal transcribed spacer (ITS) of nuclear ribosomal DNA and four non-coding regions (trnH-psbA, trnL-trnF, atpB-rbcL, rpl16 intron) of chloroplast DNA. We investigated 3, 4, 4 and 11 populations in, Ecuador, Bolivia, Argentina, and Chile, respectively, and detected six ITS genotypes (Types A-F) in G. magellanica. Five genotypes (Types A-E) were observed in the northern Andes population (Ecuador and Bolivia); only one ITS genotype (Type F) was observed in the southern Andes population (Chile and Argentina). Phylogenetic analyses showed that the ITS genotypes of the northern and southern Andes populations form different clades with high bootstrap probability. Furthermore, network analysis, analysis of molecular variance, and spatial analysis of molecular variance showed that there were two major clusters (the northern and southern Andes populations) in this species. Furthermore, in chloroplast DNA analysis, three major clades (northern Andes, Chillan, and southern Andes) were inferred from phylogenetic analyses using four non-coding regions, a finding that was supported by the above three types of analysis. The Chillan clade is the northernmost population in the southern Andes populations. With the exception of the Chillan clade (Chillan population), results of nuclear DNA and chloroplast DNA analyses were consistent. Both markers showed that the northern and southern Andes populations of G. magellanica were genetically different from each other. This type of clear phylogeographical structure was supported by PERMUT analysis according to Pons & Petit (1995, 1996). Moreover, based on our preliminary estimation that is based on the ITS sequences, the northern and southern Andes clades diverged ~0.63-3 million years ago, during a period of upheaval in the Andes. This suggests

Power supply for pumping systems in northern Chile: Photovoltaics as alternative to grid extension and diesel engines

International Nuclear Information System (INIS)

Chueco-Fernandez, Francisco J.; Bayod-Rujula, Angel A.

2010-01-01

This paper examines and compares the cost-effectiveness to energize pumping systems in remote areas on northern Chile by means of photovoltaic systems, diesel engines and grid extension. Variables such as the distance to the power grid, the voltage grid, the prices of electricity and fuel, and the required investments, are taken into account. The comparison is made for wide range of variable values, distances and pumping requirements. The results obtained are useful for choosing the best alternative for the power supply of pumping systems in wells in Northern Chile. (author)

Chile.

Science.gov (United States)

1988-09-01

Chile is a long (2650 miles), narrow (250 miles at widest point) country sandwiched between the Andes mountains and the Pacific. The northern desert is rich in copper and nitrates; the temperate middle region is agricultural and supports the major cities, including Santiago, the capital, and the port of Valparaiso; and the southern region is a cold and damp area of forests, grasslands, lakes, and fjords. The country is divided into 12 administrative regions. Chile's population of 12.5 million are mainly of Spanish or Indian descent or mestizos. Literacy is 92.3%, and the national language is Spanish. Infant mortality is 18.1/1000, and life expectancy is 68.2 years. 82% of the people are urban, and most are Roman Catholics. Chile was settled by the Spanish in 1541 and attached to the Viceroyalty of Peru. Independence was won in 1818 under the leadership of Bernardo O'Higgins. In the 1880s Chile extended its sovereignty over the Strait of Magellan in the south and areas of southern Peru and Bolivia in the north. An officially parliamentary government, elected by universal suffrage, drifted into oligarchy and finally into a military dictatorship under Carlos Ibanez in 1924. Constitutional government was restored in 1932. The Christian Democratic government of Eduardo Frei (1964-70) inaugurated major reforms, including land redistribution, education, and far-reaching social and economic policies. A Marxist government under Salvador Allende lasted from 1970 to 1973 when the present military government of General Pinochet Ugarte took power, overthrew Allende, abolished the Congress, and banned political parties. It has moved the country in the direction of a free market economy but at the cost of systematic violations of human rights. A new constitution was promulgated in 1981, and congressional elections have been scheduled for October, 1989. A "National Accord for Transition to Full Democracy" was mediated by the Catholic Church in 1985. The social reforms of the

Glacialmorphological reconstruction of glacier advances and glacial lake outburst floods at the Cachapoal glacier in the Dry Central Andes of Chile (34°S)

Science.gov (United States)

Iturrizaga, Lasafam; Charrier, Reynaldo

2013-04-01

Throughout the Andes Mountain range of South America a general trend of glacier shrinkage has taken place in the last century. Only a few glaciers have shown a rather non-continuous trend of glacier retreat and temporally advanced or even surged during the mid-19th to 20th century. One of the earliest assumed glacier surges has occurred in the upper Cachapoal catchment area at the homonymous glacier. In climatic respect the Cachapoal glacier is located in the transition zone from the most southern part of the Dry Central Andes of Chile to the more humid zone of the Wet Andes. The region is affected mainly by winter precipitation deriving from the Westerlies. The debris-covered, 12 km-long Cachapoal glacier represents one of the largest valley glaciers in the Central Andes. It is an avalanche-fed glacier with an almost 1500 m-high head wall in its upper catchment area flowing down from Picos del Barroso (5180 m) and terminates at an elevation of 2630 m a.s.l. with a bifurcated glacier tongue. A large moraine complex, almost 2 km in length and 500 m in width, separates the two glacier lobes. During times of advanced glacier tongue positions the Ríos Molina and Cachapoal may be have blocked independently at two distinct localities which are situated about 2300 m apart from each other. A blockage with temporal lake formation has occurred at least in the years 1848, 1955 and 1981 (cf. Plagemann 1887, Peña 1981), from which the rupture of the earliest glacier barrier has been the most devastating. This event is locally reminded as "la gran avenida en seco" in the historical record. Geomorphological evidence of the past historical and modern glacier expansions is given in the proglacial area by a fresh dead-ice hummocky topography and glacial trimlines at the valley flanks. More down valley broad outwash plains and boulder clusters indicate past high energy floods produced by glacier lake outbursts. Regarding the small size of the catchment area of the Río Molina

Subvolcanic contact metasomatism at El Laco Volcanic Complex, Central Andes Metasomatismo de contacto subvolcánico en el Complejo Volcánico El Laco, Andes centrales

Directory of Open Access Journals (Sweden)

José A Naranjo

2010-01-01

Full Text Available Studies of drill cores from the Pasos Blancos area at El Laco in the central Andes, northern Chile, give evidence of an intense and extensive subvolcanic contact-metasomatic process. This process resulted from shallow-level emplacement of very volatile-rich iron-oxide magma, with discharge of volatiles that resulted in extensive fracturing of overlying volcanic rocks. The brecciated rocks were altered (mainly extensive scapolitization and formation of pyroxene by hot magmatic fluids emitted from the cooling intrusion , and accompanied by magnetite deposition. With time and decreasing temperature, the metasomatic fluids evolved to fluids of hydrothermal character, and a final recent geothermal event took place that deposited superficial gypsum over a large part of the El Laco Volcanic Complex.Estudios realizados en testigos de sondajes en el area de Pasos Blancos en El Laco, en los Andes Centrales del norte de Chile, dan evidencias de un intenso y extenso proceso subvolcánico de metasomatismo de contacto. Este proceso es el resultado de un emplazamiento a poca profundidad de un magma de óxido de fierro muy rico en volátiles y cuya descarga de gases produjo un intenso fracturamiento de las rocas sobrepuestas. Las rocas brechizadas fueron alteradas (principalmente una extensa escapolitización y formación de piroxeno, junto con la depositación de magnetita, por los fluidos magmáticos calientes emitidos por la intrusión durante su enfriamiento. Los fluidos metasomáticos evolucionaron en el tiempo y con la disminución de temperatura, a fluidos de carácter hidrotermal y finalmente tuvo lugar un evento geotérmico reciente, el cual depositó yeso superficial en gran parte del Complejo Volcánico El Laco.

The shallow-water chitons (Mollusca, Polyplacophora of Caldera, Region of Atacama, northern Chile

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Juan Francisco Araya

2015-03-01

Full Text Available The Molluscan species of the northern littoral of Chile have been sparsely studied. This work reviews for the first time the diversity of polyplacophoran molluscs around the port of Caldera, in the Region of Atacama (26°45’49”S; 70°45’17”W to 27°20’23”S; 70°56’46”W, northern Chile. Eleven species were found in this study: Acanthopleura echinata (Barnes, 1824; Callistochiton pulchellus (Gray, 1828; Calloplax vivipara (Plate, 1899, Chaetopleura peruviana (Lamarck, 1819; Chiton cumingsii Frembly, 1827; Chiton granosus Frembly, 1827; Chiton magnificus Deshayes, 1827; Enoplochiton niger (Barnes, 1824, Radsia barnesii (Gray, 1828, Tonicia atrata (G. B. Sowerby II, 1840 and Tonicia chilensis (Frembly, 1827. All of the species occurring in the area have distributions in the southeastern Pacific Ocean, from Ecuador to central Chile, and three of them are species endemic to the Chilean coasts (Calloplax vivipara, Radsia barnesii, and Tonicia atrata. This diversity of species is comparable to that of better surveyed faunas of central and southern Chile or Patagonia. Of the eleven species recorded, the geographic distribution records for Callistochiton pulchellus, Radsia barnesii and Tonicia atrata are extended, and Calloplax vivipara is found alive again after 40 years, filling a gap in its known distribution. Illustrations of living specimens in their habitat, distribution records and a taxonomic key for all the studied taxa are also provided.

Glacial Hazards in Chile: Processes, Assessment, Mitigation and Risk Management Strategies

Science.gov (United States)

Glasser, N. F.; Wilson, R.; Casassa, G., Sr.; Reynolds, J.; Harrison, S.; Shannon, S. R.; Schaefer, M.; Iribarran, P.

2017-12-01

Glacial Lake Outburst Floods (GLOFs) are capable of travelling considerable distances from their source and they represent one of the most important glacial hazards. In line with observations in other parts of the world, the frequency of GLOF events in Chile has increased in recent decades highlighting the need to quantify the flood risk posed to downstream areas. This poster presents the work of the `Glacial Hazards in Chile' project which aims to (1) better understand the processes that govern the development of GLOFs in Chile, (2) estimate the socio-economic effects of GLOFs in Chile, and (3) provide a GLOF risk assessment framework that can be applied to Chile and other lower income countries globally. As an initial step towards the completion of these aims, we have recently compiled the first glacial lake inventory for the central and Patagonian Andes, which details the temporal development of glacial lakes in this region over the past three decades. This analysis was used to identify two lakes of interest that were visited during a fieldwork expedition in February 2017. The first of these, Lago Chileno in Patagonia, has recently produced a large GLOF causing significant damage to the downstream floodplain, whilst the second was identified as one of the fastest growing lakes in the central Andes. Both these lakes were surveyed using aerial imagery acquired with a drone and a custom-built bathymetry boat, data from which will help to improve our understanding of the physical processes associated with glacial lake development and failure within the Chilean Andes.

Three new species of Neofidelia (Hymenoptera: Apoidea: Megachilidae) from Northern Chile.

Science.gov (United States)

Dumesh, Sheila; Packer, Laurence

2013-02-01

Neofidelia apacheta Dumesh and Packer, sp. nov., N. camanchaca Dumesh and Packer, sp. nov., and N. submersa Dumesh and Packer, sp. nov. are described from northern Chile. Neofidelia apacheta is known from large numbers of specimens and localities at moderately high elevation (1600-3200m). Neofidelia camanchaca is only known from the ho-lotype male. Neofidelia submersa is known from the holotype male and a pair of paratypes in poor condition, all from a coastal fog oasis. Comparisons are made with the two previously described species of the genus. The collection of N. apa-cheta from so far north in Chile suggests that Neofidelia is likely to be found in southern Peru. A key for the five species of the genus is provided.

Calcite Twin Analysis in the Central Andes of Northern Argentina and Southern Bolivia

Science.gov (United States)

Hardesty, E.; Hindle, D.

2005-12-01

The use of calcite twinning to infer compression directions and strain axes patterns has been applied widely in both fold and thrust belts, and continental interiors. Calcite twinning is noted to be one of the most precise methods for determining the internal strain of deformed rocks. Until now, such data from the deformed plate boundary of the Central Andes were lacking. This study has examined twinning orientations along the deformed Andean foreland (southern Bolivia and northern Argentina) from -25 to -20 latitude. In the Central Andes, we find an abundance of calcite twins in intervals of the Cretaceous age Yacorite limestone. Twin samples were collected, measured for orientation and type (I and II can be best used for strain analysis), and processed using the Groshong method, to give resultant strain tensors. The orientations of the twin short axes trend mostly NE-SW, which is close to the plate convergence direction. However, in a limited number of samples from the north, adjacent to the southern culmination of the active Subandean fold thrust belt, they trend NW-SE. This difference may be related to the more active, or more recent, shortening of the southern portion of the Eastern Cordillera, south of the culmination of the Subandean belt. This implies that twin short axes vary consistently with respect to geographic location and local tectonic regime. NW-SE trends in the northern region match well with fault kinematic studies in rocks pre-dating the San Juan del Oro unconformity (9-10 Ma). NE-SW trends in the south could correspond to much younger (~1-3 Ma) fault kinematic trends. In the Eastern Cordillera, where there is present day tectonic activity, the plunges of the twin short axes are found to be almost horizontal. This suggests that the twins were formed after folding occurred.

Calculated WIMP signals at the ANDES laboratory: comparison with northern and southern located dark matter detectors

Science.gov (United States)

Civitarese, O.; Fushimi, K. J.; Mosquera, M. E.

2016-12-01

Weakly interacting massive particles (WIMPs) are possible components of the Universe’s dark matter (DM). The detection of WIMPs is signaled by the recoil of the atomic nuclei which form a detector. CoGeNT at the Soudan Underground Laboratory (SUL) and DAMA at the Laboratori Nazionali del Gran Sasso (LNGS) have reported data on annual modulation of signals attributed to WIMPs. Both experiments are located in laboratories in the Northern Hemisphere. DM detectors are planned to operate (or already operate) in laboratories in the Southern Hemisphere, including SABRE at Stawell Underground Physics Laboratory (SUPL) in Australia, and DM-ICE in Antarctica. In this work we have analyzed the dependence of diurnal and annual modulation of signals, pertaining to the detection of WIMP, on the coordinates of the laboratory, for experiments which may be performed in the planned new Agua Negra Deep Experimental Site (ANDES) underground facility, to be built in San Juan, Argentina. We made predictions for NaI and Ge-type detectors placed in ANDES, to compare with DAMA, CoGeNT, SABRE and DM-ICE arrays, and found that the diurnal modulation of the signals, at the ANDES site, is amplified at its maximum value, both for NaI (Ge)-type detectors, while the annual modulation remains unaffected by the change in coordinates from north to south.

Calculated WIMP signals at the ANDES laboratory: comparison with northern and southern located dark matter detectors

International Nuclear Information System (INIS)

Civitarese, O; Mosquera, M E; Fushimi, K J

2016-01-01

Weakly interacting massive particles (WIMPs) are possible components of the Universe’s dark matter (DM). The detection of WIMPs is signaled by the recoil of the atomic nuclei which form a detector. CoGeNT at the Soudan Underground Laboratory (SUL) and DAMA at the Laboratori Nazionali del Gran Sasso (LNGS) have reported data on annual modulation of signals attributed to WIMPs. Both experiments are located in laboratories in the Northern Hemisphere. DM detectors are planned to operate (or already operate) in laboratories in the Southern Hemisphere, including SABRE at Stawell Underground Physics Laboratory (SUPL) in Australia, and DM-ICE in Antarctica. In this work we have analyzed the dependence of diurnal and annual modulation of signals, pertaining to the detection of WIMP, on the coordinates of the laboratory, for experiments which may be performed in the planned new Agua Negra Deep Experimental Site (ANDES) underground facility, to be built in San Juan, Argentina. We made predictions for NaI and Ge-type detectors placed in ANDES, to compare with DAMA, CoGeNT, SABRE and DM-ICE arrays, and found that the diurnal modulation of the signals, at the ANDES site, is amplified at its maximum value, both for NaI (Ge)-type detectors, while the annual modulation remains unaffected by the change in coordinates from north to south. (paper)

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

Glacial lakes of the Central and Patagonian Andes

Science.gov (United States)

Wilson, Ryan; Glasser, Neil F.; Reynolds, John M.; Harrison, Stephan; Anacona, Pablo Iribarren; Schaefer, Marius; Shannon, Sarah

2018-03-01

The prevalence and increased frequency of high-magnitude Glacial Lake Outburst Floods (GLOFs) in the Chilean and Argentinean Andes suggests this region will be prone to similar events in the future as glaciers continue to retreat and thin under a warming climate. Despite this situation, monitoring of glacial lake development in this region has been limited, with past investigations only covering relatively small regions of Patagonia. This study presents new glacial lake inventories for 1986, 2000 and 2016, covering the Central Andes, Northern Patagonia and Southern Patagonia. Our aim was to characterise the physical attributes, spatial distribution and temporal development of glacial lakes in these three sub-regions using Landsat satellite imagery and image datasets available in Google Earth and Bing Maps. Glacial lake water volume was also estimated using an empirical area-volume scaling approach. Results reveal that glacial lakes across the study area have increased in number (43%) and areal extent (7%) between 1986 and 2016. Such changes equate to a glacial lake water volume increase of 65 km3 during the 30-year observation period. However, glacial lake growth and emergence was shown to vary sub-regionally according to localised topography, meteorology, climate change, rate of glacier change and the availability of low gradient ice areas. These and other factors are likely to influence the occurrence of GLOFs in the future. This analysis represents the first large-scale census of glacial lakes in Chile and Argentina and will allow for a better understanding of lake development in this region, as well as, providing a basis for future GLOF risk assessments.

Discovering the Complexity of Capable Faults in Northern Chile

Science.gov (United States)

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.

Weathering as the limiting factor of denudation in the Western escarpment of the Andes

Science.gov (United States)

Abbühl, L. M.; Schlunegger, F.; Kracht, O.; Ramseyer, K.; Rieke-Zapp, D.; Aldahan, A.; von Blanckenburg, F.

2009-04-01

A crucial issue in process geomorphology is the search for the scale and the extent to which precipitation, and climate in general, influences the nature and the rates of sediment transfer (weathering, erosion, sediment transport and deposition). We present an analysis of the possible interplay between precipitation, weathering and denudation rates for the western Andean slope between the Cordillera and the Pacific coast. It is based on morphometric studies and quantitative 10Be denudation rate estimates of three transverse river systems (Piura at 5°S, Pisco at 13°S, and Lluta at 18°S) draining the Western escarpment of the Peruvian and North Chilean Andes. The systems originate at elevations >3000 m above sea level, cover an area between 3000 and 10'000 km2 and discharge into the Pacific Ocean. The precipitation rate pattern implies a hyperarid climate at the coast, and semi-arid to semi-humid conditions in the Cordillera where the streams rise. There, climatic conditions are generally controlled by the easterlies that deliver moisture from the Atlantic Ocean via the low level Andean jet. The precipitation rate pattern of the Cordillera shows a North-South decreasing trend, from ca. 1000 mm/yr in Northern Peru to 150 mm/yr in Northern Chile. In these higher regions of the drainage basins, hillslopes are convex with nearly constant curvatures and are mantled by a >1 m thick regolith cover. In addition, hillslope erosion is limited to the regolith-bedrock interface. We interpret these geomorphic features to indicate weathering-controlled sediment discharge. In the lower river segments, beyond tectonic knickzones, regular precipitation is almost absent. For the case of the Piura river in Northern Peru, precipitation in this segment occurs in relation to highly episodic El Niño events related to the westerlies. This results in a supply-limited sediment discharge, leading to predominance of channelized processes on the hillslopes, a spare regolith cover and an

A new species of Eccopsis Zeller (Lepidoptera, Tortricidae from the coastal valleys of northern Chile, with the first continental record of E. galapagana Razowski & Landry

Directory of Open Access Journals (Sweden)

Héctor A. Vargas

2011-06-01

Full Text Available A new species of Eccopsis Zeller (Lepidoptera, Tortricidae from the coastal valleys of northern Chile, with the first continental record of E. galapagana Razowski & Landry. Eccopsis Zeller, 1852 is reported for the first time from Chile. Eccopsis razowskii Vargas, n. sp. is described and illustrated based on specimens reared from larvae collected on native Acacia macracantha Willd. (Fabaceae in the coastal valleys of the northern Chilean desert. Eccopsis galapagana Razowski & Landry, 2008, previously known only from the Galapagos Islands, Ecuador, is recorded for the first time from continental South America. Larvae of the latter were collected in northern Chile feeding on Prosopis alba Griseb (Fabaceae.

Nurse effect in seedling establishment: facilitation and tolerance to damage in the Andes of central Chile Efecto nodriza en el establecimiento de plántulas: facilitación y tolerancia al daño en los Andes de Chile central

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IAN S ACUÑA-RODRÍGUEZ

2006-09-01

Full Text Available Nurse effects, which occur when one plant species enhances the survival or growth of another plant species, are predicted to be most relevant in stressful environments. These effects are particulary important during seedling establishment due to their vulnerability to both biotic and abiotic factors, such as herbivory and drought. Tolerance to herbivory reflects the degree to which plants are able to regrow and reproduce after damage, and should vary with resource availability. In the high Andes of central Chile, the cushion plant Laretia acaulis (Apiaceae acts as a buffer against environmental stress, enhancing survival of several associated plant species. We hypothesized that tolerance to herbivory of seedlings growing inside the canopy of L. acaulis should be greater than that of seedlings growing outside the cushion plant. We conducted a field experiment to test this hypothesis for two native perennial species in the high Andes of central Chile: Hordeum comosum (Poaceae and Haplopappus anthylloides (Asteraceae. Seedlings of each species were planted inside and outside L. acaulis cushions and half of them received manual damage (50 % foliar tissue removed. Seedlings growing inside the nurse species showed high survival independent of the damage treatment. Whereas position (inside or outside the cushion plant did not affect tolerance of Haplopappus anthylloides, it significantly affected tolerance of Hordeum comosum. Thus, we found similar survival of damaged and control seedlings of H. comosum inside the cushions, but survival of damaged seedlings in the bare ground was lower than that of control seedlings. We verified the occurrence of nurse effects of Laretia acaulis on the establishment of both species, and detected enhancement of tolerance to damage in Hordeum comosum in this stressful habitatSe ha sugerido que el efecto nodriza, el cual se evidencia cuando una especie vegetal incrementa la supervivencia o el crecimiento de otra, es m

Subduction zone guided waves in Northern Chile

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Garth, Thomas; Rietbrock, Andreas

2016-04-01

Guided wave dispersion is observed in subduction zones as high frequency energy is retained and delayed by low velocity structure in the subducting slab, while lower frequency energy is able to travel at the faster velocities associated with the surrounding mantle material. As subduction zone guided waves spend longer interacting with the low velocity structure of the slab than any other seismic phase, they have a unique capability to resolve these low velocity structures. In Northern Chile, guided wave arrivals are clearly observed on two stations in the Chilean fore-arc on permanent stations of the IPOC network. High frequency (> 5 Hz) P-wave arrivals are delayed by approximately 2 seconds compared to the low frequency (young subducting lithosphere also has the potential to carry much larger amounts of water to the mantle than has previously been appreciated.

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

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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...

A remote sensing assessment of the impact of the 2010 Maule, Chile earthquake (Mw 8.8) on the volcanoes of the southern Andes

Science.gov (United States)

Pritchard, M. E.; Welch, M.; Jay, J.; Button, N.

2011-12-01

There are tantalizing, but controversial, indications that great earthquakes affect arc-wide volcanic activity. For example, analysis of historic eruptions at volcanoes of the southern Andes has shown that 3-4 eruptions were likely seismically triggered by Mw > 8 earthquakes in the Chile subduction zone -- particularly the 1906 and 1960 earthquakes (e.g., Watt et al., 2009). However, the 27 February 2010 Mw 8.8 Maule, Chile earthquake that ruptured the subduction zone between the 1960 and 1906 earthquakes does not appear to have triggered 3-4 volcanic eruptions in the same area in the 12 months after the event. In an effort to understand the relation between a large earthquake and volcanic unrest, we use a variety of satellite instruments to look for more subtle (i.e., not leading to eruption), but detectable change in thermal or deformation activity at the volcanoes of the southern Andes after the Maule earthquake and its aftershocks. For all of the volcanoes in the catalog of the Smithsonian Institution (approximately 80), we use nighttime MODIS and ASTER data to assess the thermal activity and ALOS InSAR data to characterize the surface deformation before and after the earthquake. The ALOS InSAR data are not ideal for detecting changes in deformation before and after the earthquake because of the small number of acquisitions in austral summer as well as ionospheric and tropospheric artifacts. We estimate that we could detect deformation > 5 cm/year. Similarly, the ASTER and MODIS data suffer respectively from poor temporal and spatial resolution of thermal anomalies. We update previous InSAR work that identified at least 8 areas of volcanic deformation in the southern Andes related to eruptive processes, subsidence of past lava flows, or surface uplift not associated with an eruption (Fournier et al., 2010). Of greatest interest are the two volcanic areas with the largest deformation signals between 2007-2008 (both > 15 cm/yr in the radar line of sight): Laguna

Diversidad de la familia Carabidae (Coleoptera en Chile Diversity of the family Carabidae (Coleoptera in Chile

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SERGIO ROIG-JUÑENT

2001-09-01

Full Text Available Carabidae constituye dentro de los coléopteros chilenos, la cuarta familia en importancia por su cantidad de especies. El presente trabajo incluye una breve compilación acerca de la historia de la familia y de las primeras expediciones realizadas en Chile. También se realizan comparaciones de la diversidad de carábidos chilenos con respecto a otros países y el Neotrópico. Para Chile, se conocen 21 tribus, con 95 géneros y 365 especies, que representan el 38,8, 28,8 y 7,9 % de la fauna del Neotrópico, respectivamente. Chile posee un bajo número de tribus comparado con otros países, sin embargo, constituye un área importante por la presencia de seis tribus relictuales, principalmente pangeicas o gondwánicas. Chile posee 18 géneros endémicos (18,5 % de su fauna de Carabidae, 28 cuya distribución está restringida a Chile y Argentina y seis restringidos a Chile, Argentina y Uruguay. La cantidad de especies presentes en Chile es inferior a la que poseen otros países de América del Sur, pero la cantidad de especies endémicas es muy alta (204 y representa el 55,8 % de su fauna de carábidos. El alto grado de endemismo que posee Chile con respecto a otros países de América del Sur puede deberse a su condición de aislamiento, siendo las barreras más importantes la región desértica del norte y la cordillera de Los Andes. Este hecho también se vislumbra por la ausencia de importantes tribus neotropicales como Galeritini, Scaritini y Brachinini. También se incluyen en este trabajo claves para la identificación de todas las tribus y géneros presentes en Chile, como así también una breve descripción acerca de la diversidad y ambientes en los que se encuentra cada géneroThe family Carabidae is the fourth largest Coleoptera family in Chile. The present work includes a brief compilation on the taxonomic history of the family and the first expeditions to Chile. In addition, knowledge of carabid diversity in Chile is compared with

Changes of glaciers in the Andes of Chile and priorities for future work.

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Pellicciotti, F; Ragettli, S; Carenzo, M; McPhee, J

2014-09-15

Glaciers in the Andes of Chile seem to be shrinking and possibly loosing mass, but the number and types of studies conducted, constrained mainly by data availability, are not sufficient to provide a synopsis of glacier changes for the past or future or explain in an explicit way causes of the observed changes. In this paper, we provide a systematic review of changes in glaciers for the entire country, followed by a discussion of the studies that have provided evidence of such changes. We identify a missing type of work in distributed, physically-oriented modelling studies that are needed to bridge the gap between the numerous remote sensing studies and the specific, point scale works focused on process understanding. We use an advanced mass balance model applied to one of the best monitored glaciers in the region to investigate four main research issues that should be addressed in modelling studies for a sound assessment of glacier changes: 1) the use of physically-based models of glacier ablation (energy balance models) versus more empirical models (enhanced temperature index approaches); 2) the importance of the correct extrapolation of air temperature forcing on glaciers and in high elevation areas and the large uncertainty in model outputs associated with it; 3) the role played by snow gravitational redistribution; and 4) the uncertainty associated with future climate scenarios. We quantify differences in model outputs associated with each of these choices, and conclude with suggestions for future work directions. © 2013 Elsevier B.V. All rights reserved.

Microbial eukaryote diversity in the marine oxygen minimum zone off northern Chile

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Parris, Darren J.; Ganesh, Sangita; Edgcomb, Virginia P.; Stewart, Frank J.; DeLong, Edward

2014-01-01

Molecular surveys are revealing diverse eukaryotic assemblages in oxygen-limited ocean waters. These communities may play pivotal ecological roles through autotrophy, feeding, and a wide range of symbiotic associations with prokaryotes. We used 18S rRNA gene sequencing to provide the first snapshot of pelagic microeukaryotic community structure in two cellular size fractions (0.2-1.6 µm, >1.6 µm) from seven depths through the anoxic oxygen minimum zone (OMZ) off northern Chile. Sequencing ...

First remarks on the nesting biology of Hypodynerus andeus (Packard (Hymenoptera, Vespidae, Eumeninae in the Azapa valley, northern Chile

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Felipe Méndez-Abarca

2012-06-01

Full Text Available First remarks on the nesting biology of Hypodynerus andeus (Packard (Hymenoptera, Vespidae, Eumeninae in the Azapa valley, northern Chile. Some aspects about the nesting biology of the potter wasp Hypodynerus andeus (Packard, 1869 are reported for the first time. Observations were carried out at the Azapa valley, coastal desert of northern Chile. A total of sixty nests were collected and examined, each composed by 1-14 cells, most of them found attached to concrete lamp posts. The only preys recorded in the cells were Geometridae (Lepidoptera caterpillars and the presence of the parasitoid Anthrax sp. (Diptera, Bombyliidae was also recorded. A number of arthropods belonging to different groups, mainly spiders, were found occupying empty nests.

Historia y documentos sobre la colonización alemana en Chile.

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Carrasco , Eduardo; Gleisner , Christine; Winkler , Lisette; de Pablo , Elisabeth

2007-01-01

Fonds audiovisuel du programme ESCoM-AAR (Equipe Sémiotique Cognitive et nouveaux Médias - Archives Audiovisuelles de la Recherche; 2001 - 2016).; Eduardo CARRASCO, Spezialist der Geschichte sowie des Kulturmanagements (Universität von Los Andes in Santiago de Chile) und Christine GLEISNER haben an der pontifikal-katholischen Universität Chiles Geschichte studiert. In dieser Reportage sprechen Sie von Ihren Arbeiten für die Archive « Emilio Held Winkler » des Chilenisch-Deutschen Verbands in ...

Oxygenation variability off Northern Chile during the last two centuries

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Díaz-Ochoa, J. A.; Pantoja, S.; de Lange, G. J.; Lange, C. B.; Sánchez, G. E.; Acuña, V. R.; Muñoz, P.; Vargas, G.

2010-07-01

The Peru Chile Current ecosystem is characterized by high biological productivity and important fisheries. Although this system is likely to be severely affected by climate change, its response to current global warming is still uncertain. In this paper we analyze 10-166 year old sediments in two cores collected in Mejillones Bay, an anoxic sedimentary setting favorable for preservation of proxies. Based on a 166 year chronology we used indicators of bottom water oxygenation proxies (Mo, V, S, and the (lycopane+n-C35)/n-C31) ratio) and surface water productivity (biogenic opal, counts of diatom valves, biogenic Ba, organic carbon and chlorins) to reconstruct environmental variations in Mejillones Bay. We find that at decadal scales, and during the last two centuries, a shift in the coastal marine ecosystem off Northern Chile took place which was characterized by intense ENSO-like activity and large fluctuations in biological export productivity, in bottom water oxygenation, and increased eolic activity (inferred from Ti/Al and Zr/Al). On top of this short-term variability, a gradual increase of sulfidic conditions has occurred being even more intensified since the early 1960s.

Bloom of the Yessotoxin producing dinoflagellate Protoceratium reticulatum (Dinophyceae) in Northern Chile

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Álvarez, Gonzalo; Uribe, Eduardo; Díaz, Rosario; Braun, Mauricio; Mariño, Carmen; Blanco, Juan

2011-05-01

In summer 2007, a dinoflagellate preliminarily identified as Protoceratium reticulatum bloomed in Bahía Mejillones, northern Chile. Phytoplankton samples were analyzed in detail by light and scanning electron microscopy revealing the presence of resting cyst and motile cells of P. reticulatum. Oceanographic and phytoplankton data suggest that the bloom was initiated offshore by motile cells and germinated cysts during an upwelling pulse. These cells were advected into the bay when upwelling relaxed and grew without any relevant competitor. Phytoplankton net samples were found to contain yessotoxin as the only toxin in an estimated proportion of 0.2 and 0.4 pg cell - 1 , thus confirming that P. reticulatum is a source of yessotoxin in northern Chilean waters and consequently that it poses a risk for human health and mollusk exploitation in the area.

Parasite loads and altitudinal distribution of Liolaemus lizards in the central Chilean Andes Cargas parasitarias y distribución de lagartijas Liolaemus en los Andes de Chile central

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JOHN H. CAROTHERS

2001-09-01

Full Text Available This study compared the distributions of ten species of Liolaemus lizards in the central Chilean Andes to the distributions of four types of parasites: malaria-causing Plasmodium, gut nematodes, ticks, and mites. We wanted to see if parasite numbers might be a factor in determining distributional limits of the lizards. We found that there was no evidence of malarial infestation of the lizards, that ticks were almost absent, that more often than not mite numbers decreased at the distributional limits of the lizards, and that gut nematodes confined to the herbivorous lizards in our sample may well be beneficial rather than detrimental. Rather than parasitism, other biotic interactions (e.g., predation or competition are more likely candidates as factors influencing lizard elevational distributions, as are abiotic characteristics such as microhabitat availabilities and thermal factorsEste estudio compara las distribuciones de diez especies de lagartijas Liolaemus en los Andes de Chile central, con las distribuciones de cuatro tipos de parásitos: Plasmodium causantes de malaria, nemátodos intestinales, garrapatas y ácaros. Quisimos verificar si los números de parásitos pudieran ser un factor determinante de los límites de distribución de las lagartijas. Encontramos que no había evidencia de infestación por malaria en las lagartijas; que las garrapatas estaban casi ausentes; que los números de ácaros más a menudo decrecían que aumentaban en los límites distribucionales de las lagartijas; y que los nemátodos intestinales confinados a las lagartijas herbívoras en nuestra muestra bien podían ser beneficiosos antes que dañinos. Más bien que parasitismo, otras interacciones bióticas (e.g., depredación o competencia son candidatos más probables como factores que influyen las distribuciones altitudinales de las lagartijas, además de características abióticas tales como la disponibilidad de microhábitats y los factores térmicos

First host plant records for Iridopsis hausmanni Vargas (Lepidoptera, Geometridae in the coastal valleys of northern Chile

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Héctor A. Vargas

2014-03-01

Full Text Available First host plant records for Iridopsis hausmanni Vargas (Lepidoptera, Geometridae in the coastal valleys of northern Chile. The trees Haplorhus peruviana Engl. and Schinus molle L. (Anacardiaceae are mentioned as the first host plant records for the little known native moth Iridopsis hausmanni Vargas, 2007 (Lepidoptera, Geometridae, Ennominae in the coastal valleys of the northern Chilean Atacama Desert. This is also the first record of Anacardiaceae as host plant for a Neotropical species of Iridopsis Warren, 1894.

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

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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.

Los indios cuzcos de Chile colonial : estrategias semánticas,usos de la memoria y gestión de identidades entre inmigrantes andinos (siglos XVI-XVII)1

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Valenzuela-Márquez, Jaime

2010-01-01

El artículo explora la inmigración de indígenas de los Andes en Chile colonial y las estrategias que desarrollaron para insertarse en el medio urbano de Santiago. En particular, se estudia la emergencia de un gentilicio, el cuzco, como categoría de identidad, como autoreferencia construida por los mismos inmigrantes y heredada por sus descendientes, y como denominación recogida por las instancias coloniales. This article explores the immigration of Indians from the Andes in Chile colonial ...

The subduction erosion and mantle source region contamination model of Andean arc magmatism: Isotopic evidence from igneous rocks of central Chile

International Nuclear Information System (INIS)

Stern, Charles R

2001-01-01

Continental crust may be incorporated in mantle-derived Andean magmas as these magmas rise through the crust (Hildreth and Moorbath, 1988), or alternatively, crust may be tectonically transported into the mantle by subduction of trench sediments and subduction erosion of the continental margin, and then added into the mantle source region of Andean magmas (Stern, 1991). Since the mantle has relatively low Sr, Nd, and Pb concentrations compared to continental crust, differences in the isotopic compositions of magmas erupted in different region of the Andes may be produced by relatively small differences in the amount of subducted crust added to the mantle source region of these magmas. By comparison, significantly larger amounts of crust must be assimilated by mantle-derived magmas to produce isotopic differences of similar magnitude. Therefore, constraining the process by which continental crust is incorporated in Andean magmas has important implications for understanding the chemical cycling that takes place in the Andean subduction-related magma factory. Isotopic data suggest the incorporation of a greater proportion of crust in Andean magmas erupted at the northern portion of the Southern Volcanic Zone of central Chile compared to those erupted in the southern portion of the Southern Volcanic Zone of south central Chile (SSVZ) (Stern et al., 1984; Futa and Stern, 1988; Hildreth and Moorbath, 1988). The NSVZ occurs just south of the current locus of the subduction of the Juan Fernandez Ridge. The southward migration of the locus of subduction of this ridge has resulted in decreasing subduction angle below the NSVZ, the eastward migration of the volcanic front of the Andean arc, and an increase in the crustal thickness below the arc. These factors together have caused changes, since the middle Miocene, in the isotopic composition of Andean igneous rocks of central Chile. The data indicate a close chronologic relation between the southward migrations of the locus

Rock Glacier Response to Climate Change in the Argentinian Andes

Science.gov (United States)

Drewes, J.; Korup, O.; Moreiras, S.

2017-12-01

Rock glaciers are bodies of frozen debris and ice that move under the influence of gravity in permafrost areas. Rock glaciers may store a large amount of sediments and play an important role as prime movers of debris in the Andean sediment cascade. However, little is known about how much sediment and water rock glaciers may store at the mountain-belt scale, and the few existing estimates vary considerably. We address this question for the Argentinian Andes, for which a new glacial inventory containing more than 6500 rock glaciers gives us the opportunity to analyse their relevance within the sediment cascade. We examine the inventory for catchments in five sub-regions, i.e. the Desert Andes (22°-31°S); the Central Andes (31°-36°S); the Northern Andes of Patagonia (36°-45°S); the Southern Andes of Patagonia (45°-52°S); and Tierra del Fuego (52°-55°S), together with climate variables of the WorldClim datasets, and digital topographic data, to estimate how rock-glacier extents may change under different past and future climate scenarios. We observe for the northern Desert Andes that rock glacier toes are at 4000 to 5000 m a.s.l. and a mean annual temperature range of 3° and 8°C, though most rock glaciers are in areas with mean annual temperatures between -5 and 5°C, marking a distinct thermal niche. Rock glaciers are traditionally viewed as diagnostic of sporadic alpine permafrost and their toes are often near the annual mean 0°C isotherm. However, we find that only rock glaciers in the southern Desert Andes and Central Andes are located where annual mean temperature is -2°C. Future scenarios project an increase of > four degrees in these areas, which may further degrade ground ice and potentially change the rates at which rock glaciers advance. Where active rock glaciers become inactive their coarse material, which was formerly bound by ice, may be released into the sediment cascade, whereas accelerating or rapidly downwasting rock glaciers may either

Co-evolution of land use changes, water quality deterioration and social conflicts in arid Northern Chile

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Zang, Carina; Dame, Juliane

2017-04-01

Water scarcity concerns not only the limited availability of water but also water of inadequate quality in terms of its designated purposes. Arid regions, such as found in Northern Chile, are especially vulnerable to water contamination, owing to missing dilution. Additionally, the national government of Chile's goal to make the country a globally important food exporter has led to the widespread expansion of agricultural surfaces over the last 20 years, thereby increasing pressure on limited water resources and water quality. Mining, being one of the most important economic sectors in Chile, threatens both surface and groundwater quality. This scenario increases the potential for water use conflicts, which is further compounded by the demand for potable water provided by rivers and groundwater. In order to better understand the role of both physical and human dimensions of water quality, this research uses a socio-hydrological conceptual framework. This approach is used in order to broaden the scope of hydrology to include the anthropogenic impact on the environment. It therefore focuses on human and natural interactions and two-sided feedback loops, instead of purely hydrological cycles. Using the case study of the Rio Huasco watershed changes in water quality, which originate at the nexus of physical parameters, social conflicts and changing land use regimes in Northern Chile, are discussed. This region was chosen as an exemplary case for the development of Chile's arid regions: the valley is located at the southern edge of the Atacama Desert, where water scarcity is a major problem. At present, the watershed is predominantly used for agriculture. Many small farmers still practise strip cultivation, but are pressured to shift towards an international export-orientated future with monocultures. International companies are planning to mine the Pascua Lama Mine, one of the world's biggest gold reserves located in the headwaters of the Rio Huasco. Meanwhile, the

Latest Miocene-Pliocene Tiliviche Paleolake, Atacama Desert, Northern Chile 19.5°S: Paleoclimatic and Paleohydrologic Implications

Science.gov (United States)

Kirk-Lawlor, N. E.; Jordan, T. E.; Rech, J.; Lehmann, S.

2010-12-01

Endorheic paleolake deposits of diatomite, mudstone, sandstone, and evaporites are exposed in the Atacama Desert of northern Chile. This study focuses on a major latest Miocene-Pliocene paleolake system centered at 19.5°S, near Tiliviche. A diatiomite unit, up to 35m thick, composed of 0.2-1.5m thick beds of massive, white diatiomite, free of plant matter and root traces, is interpreted have formed from lacustrine diatom blooms. At its maximum extent, the lake would have had a surface area of roughly 200 km2, based on the extent of the diatomite unit, and might have been 50-100 m deep, as inferred by the relationship between the diatomite unit and modern topography. The Tiliviche paleolake initially formed before 6.4 Ma, and much of its sedimentary record formed under a wetter climatic and hydrologic regime than the present. Prior to 3.5 Ma, the lake had evolved into a groundwater-fed saltpan. Polygonally fractured efflorescent halite evaporite and bedded gypsum and gypsarenite evaporite deposits that overlie the diatomite unit are evidence of this saltpan environment. The modern Atacama Desert is hyperarid, with an average precipitation of 2 mm/yr in the driest areas. The paleosol record demonstrates that hyperarid conditions dominated this region since the middle Miocene, albeit with multiple fluctuations to less arid conditions of short to moderately long duration. This hyperaridity is due to the desert’s latitude, ocean currents and the rainshadow created by the Andes. There is no evidence that the rainshadow effect has diminished since the late Miocene, hence global climate changes affecting ocean temperatures and atmospheric patterns likely caused the wetter periods in the Atacama. In particular, prior workers noted wetter conditions in the region ~6-5 Ma, followed by a return to hyper-arid conditions. The regional Pliocene return to hyperaridity coincided with the desiccation of the Tiliviche endorheic lake system. During the late Miocene (~6-5 Ma) wetter

A dichotomous species of Codium (Bryopsidales, Chlorophyta is colonizing northern Chile Una especie dicotómica de Codium (Bryopsidales, Chlorophyta está colonizando el norte de Chile

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ALEJANDRA GONZÁLEZ

2004-06-01

Full Text Available In late 2001 and early 2002, a dichotomous species of Codium appeared colonizing the low intertidal and shallow subtidal bottoms of Caldera Bay, northern Chile (27° 03’ S, 70° 51’ W. Due to the ecological and economic impact the species is having in Caldera Bay and its potential spread along the Chilean coastline, we studied the taxonomic identity of the species and examined its relationships with other dichotomous species of Codium reported for temperate Pacific South America. Morphological analyses suggest that the seaweeds from Caldera Bay belong to Codium fragile (Suringar Hariot. Not only is there strong agreement in internal and external morphological characters, but among all the species reported for Peru and Chile, this is the only one exhibiting utricles with rounded, apiculate tip terminating in a mucron. This species has a broad geographic distribution in temperate waters. In Chile it was known only from the coasts of Valdivia to the Straits of Magellan (39° 48’ S, 73° 26’ W to 53° 10’ S, 73° 49’ W. This is the first record of C. fragile in northern Chile, and this study discusses several alternative hypotheses for the presence of the species into this area. The morphological characteristics of the material collected in Caldera partially agree with diagnostic characters known for C. fragile subspecies tasmanicum and C. fragile subspecies tomentosoides. However, the rapid population spread of the species in northern Chile, and recent molecular analysis support the identification of this form as the invasive C. fragile subspecies tomentosoidesA fines de 2001 y principio de 2002, apareció en el norte de Chile una especie del género Codium, de morfología dicotómica, colonizando los niveles intermareales y submareales de la Bahía de Caldera (27° 03’ S, 70° 51’ O. Debido al impacto ecológico y económico que ha provocado esta especie en la Bahía de Caldera y a su dispersión potencial a lo largo de la costa de

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

Science.gov (United States)

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

Thallium isotope variations in an ore-bearing continental igneous setting: Collahuasi Formation, northern Chile

Science.gov (United States)

Baker, R. G. A.; Rehkämper, M.; Ihlenfeld, C.; Oates, C. J.; Coggon, R.

2010-08-01

Thallium is a highly incompatible element and a large fraction of the bulk silicate Earth Tl budget is, therefore, expected to reside in the continental crust. Nonetheless, the Tl isotope systematics of continental rocks are essentially unexplored at present. Here, we present new Tl isotope composition and concentration data for a suite of 36 intrusive and extrusive igneous rocks from the vicinity of porphyry Cu deposits in the Collahuasi Formation of the Central Andes in northern Chile. The igneous lithologies of the rocks are variably affected by the hydrothermal alteration that accompanied the formation of the Cu deposits. The samples display Tl concentrations that vary by more than an order of magnitude, from 0.1 to 3.2 μg/g, whilst ɛ 205Tl ranges between -5.1 and +0.1 (ɛ 205Tl is the deviation of the 205Tl/ 203Tl isotope ratio of a sample from a standard in parts per 10 4). These variations are primarily thought to be a consequence of hydrothermal alteration processes, including metasomatic transport of Tl, and formation/breakdown of Tl-bearing minerals, which are associated with small but significant Tl isotope effects. The Tl abundances show excellent correlations with both K and Rb concentrations but no co-variation with Cu. This demonstrates that Tl displays only limited chalcophile affinity in the continental crust of the Collahuasi Formation, but behaves as a lithophile element with a distribution that is primarily governed by partitioning of Tl + into K +-bearing phases. Collahuasi samples with propylitic alteration features, which are derived from the marginal parts of the hydrothermal systems, have, on average, slightly lighter Tl isotope compositions than rocks from the more central sericitic and argillic alteration zones. This small but statistically significant difference most likely reflects preferential retention of isotopically heavy Tl in alteration phases, such as white micas and clays, which formed during sericitic and argillic alteration.

Slope instabilities along the Western Andean Escarpment and the main canyons in Northern Chile

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Crosta, G.; Hermanns, R. L.; Valbuzzi, E.; Dehls, J.; Yugsi Molina, F. X.; Sepulveda, S.

2012-04-01

The western slope of the Andes of northern Chile - southern Perù is generally subdivided from the west to the east into the morphological units of: the Coastal Cordillera, Central Depression, the Western Escarpment-Precordillera and the Western Andean Cordillera. The western escarpment and Precordillera are formed by the Azapa coarse-grained clastic formation (sandstones, conglomerates, mudstones) and the Oxaya (rhyodacitic ignimbrites) and Diablo volcanoclastic formations (Oligocene and Miocene). Important uplift has been suggested between the deposition of the Oxaya and Diablo formations. The entire area has been characterized by a long-term hyperaridity (Atacama desert), initially established between 20 and 15 Ma, and this caused a strong difference between the long term continuous uplift and low denudation rates. This long sector of the central western escarpment and Precordillera is incised by deep canyons and subparallel drainage network in the upper part. The drainage network developed in two main phases: a lower-middle Miocene phase with formation of a parallel poorly structured drainage network cutting into the Oxaya formation, and presently well preserved; the canyons have been incised in the initial topography starting around 9 Ma and up to about 3.8 Ma with subsequent refilling episodes. Valley incision (ave. rate of 0.2 mm yr-1) has been controlled by topographic uplift and less arid climate (after 7 Ma). As a consequence of these geologic and climatic settings the evolution of this area has been characterized by canyon incision and extremely large slope instabilities. These slope instabilities occur in the "interfluvial" sectors of the western escarpment and Precordillera and along the canyon flanks. Landslides affecting the preserved paleosurfaces, interested by the parallel drainage network in the Oxaya formation, involve volumes of various cubic kilometres (Lluta collapse, Latagualla Landslide) and can control the drainage network. These mega

Local climate change induced by groundwater overexploitation in a high Andean arid watershed, Laguna Lagunillas basin, northern Chile

Science.gov (United States)

Scheihing, Konstantin; Tröger, Uwe

2018-05-01

The Laguna Lagunillas basin in the arid Andes of northern Chile exhibits a shallow aquifer and is exposed to extreme air temperature variations from 20 to -25 °C. Between 1991 and 2012, groundwater levels in the Pampa Lagunillas aquifer fell from near-surface to 15 m below ground level (bgl) due to severe overexploitation. In the same period, local mean monthly minimum temperatures started a declining trend, dropping by 3-8 °C relative to a nearby reference station. Meanwhile, mean monthly maximum summer temperatures shifted abruptly upwards by 2.7 °C on average in around 1996. The observed air temperature downturns and upturns are in accordance with detected anomalies in land-surface temperature imagery. Two major factors may be causing the local climate change. One is related to a water-table decline below the evaporative energy potential extinction depth of 2 m bgl, which causes an up-heating of the bare soil surface and, in turn, influences the lower atmosphere. At the same time, the removal of near-surface groundwater reduces the thermal conductivity of the upper sedimentary layer, which consequently diminishes the heat exchange between the aquifer (constant heat source of 10 °C) and the lower atmosphere during nights, leading to a severe dropping of minimum air temperatures. The observed critical water-level drawdown was 2-3 m bgl. Future and existing water-production projects in arid high Andean basins with shallow groundwater should avoid a decline of near-surface groundwater below 2 m bgl and take groundwater-climate interactions into account when identifying and monitoring potential environmental impacts.

Fires in Chile

Science.gov (United States)

2002-01-01

On February 5, 2002, the dense smoke from numerous forest fires stretched out over the Pacific Ocean about 400 miles south of Santiago, Chile. This true-color Moderate-resolution Imaging Spectroradiometer (MODIS) image shows the fires, which are located near the city of Temuco. The fires are indicated with red dots (boxes in the high-resolution imagery). The fires were burning near several national parks and nature reserves in an area of the Chilean Andes where tourism is very popular. Southeast of the fires, the vegetation along the banks of the Rio Negro in Argentina stands out in dark green. Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC

Mafic enclaves in dacitic domes and their relation with La Poruña scoria cone, Central Andes, northern Chile

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González-Maurel, O. P.; Gallmeyer, G.; Godoy, B.; Menzies, A.; le Roux, P. J.; Harris, C.

2017-12-01

Chao Dacite, Chillahuita, Cerro Pabellón, Chanka, Chac-Inca, and Cerro La Torta (or Tocorpuri) are dacitic domes of late Pleistocene age (30 to 140 ka; Renzulli et al., 2006; Tierney et al., 2016) located in Northern Chilean Central Andean province (NCCA; 17°20'S - 27°40'S). While, La Poruña is a 180 m high basaltic-andesite scoria cone erupted ca. 100 ka (Wörner et al., 2000). This scoria cone is also located at the NCCA, 26 km to the SW of Chanka and 45 km to the NW of Chao Dacite. The dacitic domes are generally porphyritic and highly crystalline lavas (30 - 50 vol % phenocrysts, plagioclase > biotite > amphibole > quartz ≥ accessory), with hyalopilitic or intersertal groundmass. These domes contain mafic enclaves, mostly andesite in composition, with plagioclase > amphibole > biotite ≥ clinopyroxene ≥ olivine ≥ accessory phenocryst (10 - 20 vol %) in a lightly oxidized groundmass with intersertal or intergranular textures. In contrast, La Poruña rocks are mostly aphanitic (75 - 85 vol % groundmass) and highly vesicular, with plagioclase > olivine ≥ clinopyroxene ≥ orthopyroxene phenocrysts in an intersertal or hyalopilitic groundmass. Although petrographically different, the composition (57 wt % SiO2; 580 ppm Sr, 87Sr/86Sr = 0.7066) of mafic enclaves from Cerro Pabellón dome are similar to the lava flows and pyroclastic blocks of La Poruña scoria cone (55 - 59 wt % SiO2; 560 - 610 ppm Sr; 0.7062 - 0.7066 87Sr/86Sr). Based on this data and the eruption ages of these volcanic structures, we suggest that the mafic enclaves and La Poruña magmas are co-genetic. Thus, we propose that the genesis of these mafic enclaves is associated with the origin of less evolved parental magmas erupted in the NCCA, such as those from La Poruña. In this case, the mafic enclaves would represent batches of less evolved magmas that ascended from deeper sources and probably contributed in the eruption of the dacitic domes. Renzulli et al., 2006. In XI Congreso Geol

Protecting Dark Skies in Chile

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Smith, R. Chris; Sanhueza, Pedro; Phillips, Mark

2018-01-01

Current projections indicate that Chile will host approximately 70% of the astronomical collecting area on Earth by 2030, augmenting the enormous area of ALMA with that of three next-generation optical telescopes: LSST, GMTO, and E-ELT. These cutting-edge facilities represent billions of dollars of investment in the astronomical facilities hosted in Chile. The Chilean government, Chilean astronomical community, and the international observatories in Chile have recognized that these investments are threatened by light pollution, and have formed a strong collaboration to work at managing the threats. We will provide an update on the work being done in Chile, ranging from training municipalities about new lighting regulations to exploring international recognition of the dark sky sites of Northern Chile.

Seasonal and elevational contrasts in temperature trends in Central Chile between 1979 and 2015

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Burger, F.; Brock, B.; Montecinos, A.

2018-03-01

We analyze trends in temperature from 18 temperature stations and one upper air sounding site at 30°-35° S in central Chile between 1979-2015, to explore geographical and season temperature trends and their controls, using regional ocean-atmosphere indices. Significant warming trends are widespread at inland stations, while trends are non-significant or negative at coastal sites, as found in previous studies. However, ubiquitous warming across the region in the past 8 years, suggests the recent period of coastal cooling has ended. Significant warming trends are largely restricted to austral spring, summer and autumn seasons, with very few significant positive or negative trends in winter identified. Autumn warming is notably strong in the Andes, which, together with significant warming in spring, could help to explain the negative mass balance of snow and glaciers in the region. A strong Pacific maritime influence on regional temperature trends is inferred through correlation with the Interdecadal Pacific Oscillation (IPO) index and coastal sea surface temperature, but the strength of this influence rapidly diminishes inland, and the majority of valley, and all Andes, sites are independent of the IPO index. Instead, valley and Andes sites, and mid-troposphere temperature in the coastal radiosonde profile, show correlation with the autumn Antarctic Oscillation which, in its current positive phase, promotes subsidence and warming at the latitude of central Chile.

Use of time series of optical and SAR images in the estimation of snow cover for the optimization of water use in the Andes of Argentina and Chile

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Salinas de Salmuni, Graciela; Cabezas Cartes, Ricardo; Menicocci, Felix

2014-05-01

This paper describes the progress in the bilateral cooperation project between academic and water resources management institutions from the Andes region of Argentina and Chile. The study zone is located in fragile ecosystems and mountain areas of the Andes (limit zone between the Province of San Juan, Argentina, and the IV Region of Coquimbo, Chile), with arid climate, where snow precipitates in the headwaters of watershed feed the rivers of the region by melting, which are the only source of water for human use, productive and energetic activities, as well as the native flora and fauna. CONAE, the Argentine Space Agency, participates in the Project through the provision of satellite data to the users and by this it contributes to ensuring the continuity of the results of the project. Also, it provides training in digital image processing. The project also includes the participation of water resource management institutions like Secretaria de Recursos Hidricos of Argentina and the Centro de Información de Recursos Naturales de Chile (CIREN), and of academic institution like the University of San Juan (Argentina) and University of La Serena (Chile). These institutions benefit from the incorporation of new methodologies advanced digital image processing and training of staff (researcher, lecturers, PhD Students and technical). Objectives: 1-Improve water distribution incorporating space technology for application in the prediction models of the stream flow. 2- Conduct an inventory of glaciers as well as studies in selected watersheds in the Andean region, aiming to know the water resource, its availability and potential risks to communities in the region. 3. Contribute to vulnerability studies in biodiversity Andean watersheds. Results: For estimation Snow cover Area, the MODIS images are appropriate due their high temporal resolution and allows for monitoring large areas (greater than 10 km) The proposed methodology (Use of snow index, NSDI) is appropriate for

Magmatic fluid inclusions from the Zaldivar Deposits, Northern Chile: The role of early metal-bearing fluids in a Porphyry copper system

NARCIS (Netherlands)

drs Campos, E.; Touret, J.L.R.; Nikogosian, I.

2006-01-01

The occurrence of a distinct type of multi-solid, highly-saline fluid inclusions, hosted in igneous quartz phenocrysts from the Llamo porphyry, in the Zaldívar porphyry copper deposit of northern Chile is documented. Total homogenization of the multi-solid type inclusions occurs at magmatic

"Magmatic fluid inclusions from the Zaldivar deposit, Northern Chile: The role of Early metal-bearing fluids in a porphyry copper system."

NARCIS (Netherlands)

drs Campos, E.; Touret, J.L.R.; Nikogosian, I.

2006-01-01

The occurrence of a distinct type of multi-solid, highly-saline fluid inclusions, hosted in igneous quartz phenocrysts from the Llamo porphyry, in the Zaldívar porphyry copper deposit of northern Chile is documented. Total homogenization of the multi-solid type inclusions occurs at magmatic

Mid-Holocene Climate and Culture Change in the Atacama Desert, Northern Chile

Science.gov (United States)

Grosjean, Martin; Núñez, Lautaro; Cartajena, Isabel; Messerli, Bruno

1997-09-01

Twenty archaeological campsites intercalated between more than 30 debris flows caused by heavy rainfall events between 6200 and 3100 14C yr B.P. have recently been discovered at Quebrada Puripica in the Atacama Desert of northern Chile. This record provides detailed information about extreme, short-lived climatic events during the hyperarid mid-Holocene period. For the first time, we found evidence of continuous human occupation in this area, filling the regional hiatus in the Atacama basin ("Silencio Arqueologico") between 8000 and 4800 14C yr B.P. The transformation of Early Archaic hunters into the complex Late Archaic cultural tradition was an adaptive process. During this time, the site was a local ecological refuge with abundant resources in a generally hostile environment.

Late Oligocene-Early Miocene compressional tectosedimentary episode and associated land-mammal faunas in the Andes of central Chile and adjacent Argentina (32 37°s)

Science.gov (United States)

Semper, Thierry; Marshall, Larry G.; Rivano, Sergio; Godoy, Estanislao

1994-01-01

A reassessment of the geologic and land-mammal fossil evidence used in attribution of a tectosedimentary episode in the Andes between 32 and 37°S to the Middle Eocene "Incaic tectonic phase" of Peru indicates that the episode occurred during Late Oligocene-Early Miocene times(~ 27-20 Ma). From west to east, three structural domains are recognized for this time span in the study area: a volcanic arc (Chile); a thin-skinned, E-verging fold-thrust belt (Cordillera Principal, Chile-Argentina border strip); and a foreland basin (Argentina). Initiation of thrusting in the Cordillera Principal fold-thrust belt produced the coeval initiation of sedimentation in the foreland basin of adjacent Argentina. This onset of foreland deposition postdates strata bearing a Divisaderan Land Mammal Age fauna (i.e. ~ 35-30 Ma) and is marked at ~ 36°30'S by the base of the "Rodados Lustrosos" conglomerates, which are conformably overlain by sedimentary rocks containing a Deseadan Land Mammal Age fauna (i.e. ~ 29-21 Ma). Geologic relationships between the thick volcanic Abanico (Coya-Machalí) and Farellones formations also demonstrate that this tectosedimentary episode practically ended at ~ 20 Ma at least in the volcanic arc, and was therefore roughly coeval with the major tectonic crisis (~ 27-19 Ma) known in northwestern Andean Bolivia some 1500 km to the north. This strongly suggests that a long, outstanding tectonic upheaval affected at least an extended 12-37°S segment of the Andean margin of South America during Late Oligocene and Early Miocene times.

A study of SO2 emissions and ground surface displacements at Lastarria volcano, Antofagasta Region, Northern Chile

Science.gov (United States)

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.

Andes: An intelligent homework helper

Science.gov (United States)

van de Sande, Brett; Vanlehn, Kurt; Treacy, Don; Shelby, Bob; Wintersgill, Mary

2007-03-01

Andes (www.andes.pitt.edu) is an intelligent tutor homework system designed for use as the homework portion of an introductory physics course. It encourages students to use good problem solving techniques and provides immediate feedback on each step of a problem solution along with hints on request. I will discuss how Andes works, from a student perspective, and present research demonstrating its effectiveness as a pedagogical tool. Then, I will discuss using Andes as a tool for conducting education research, briefly reviewing several studies conducted using Andes. Finally, I will show how logs of student solutions to Andes problems can be used to develop cognitive models of student learning.

Pollution in coastal fog at Alto Patache, Northern Chile.

Science.gov (United States)

Sträter, Ellen; Westbeld, Anna; Klemm, Otto

2010-11-01

The Atacama Desert in Northern Chile is one of the most arid places on earth. However, fog occurs regularly at the coastal mountain range and can be collected at different sites in Chile to supply settlements at the coast with freshwater. This is also planned in the fog oasis Alto Patache (20°49'S, 70°09'W). For this pilot study, we collected fog water samples in July and August 2008 for chemical analysis to find indications for its suitability for domestic use. Fog water samples were taken with a cylindrical scientific fog collector and from the net and the storage tank of a Large Fog Collector (LFC). The pHs of advective fog, originating from the stratus cloud deck over the Eastern Pacific, varied between 2.9 and 3.5. Orographic fog, which was formed locally, exhibited a pH of 2.5. About 50% of the total ionic concentration was due to sea salt. High percentages of sulfate and very high enrichment factors (versus sea salt) of heavy metals were found. Both backward trajectories and the enrichment factors indicate that the high concentrations of ions and heavy metals in fog were influenced by anthropogenic activities along the Chilean Pacific Coast such as power plants, mining, and steel industry. We found no direct indication for the importance of other sources such as the emission of dimethyl sulfide from the ocean and subsequent atmospheric oxidation for acidity and sulfate or soil erosion for heavy metal concentrations. When fog water was collected by the LFC, it apparently picked up large amounts of dry deposition which accumulated on the nets during fog-free periods. This material is rinsed off the collector shortly after the onset of a fog event with the water collected first. During the first flush, some concentrations of acidity, nitrate, As, and Se, largely exceeded the Chilean drinking water limits. Before any use of fog water for domestic purpose, its quality should be checked on a regular basis. Strategies to mitigate fog water pollution are given.

Application of PIXE to the characterization of vitreous dacites from archaeolgical sites in the Atacama region in northern Chile

Energy Technology Data Exchange (ETDEWEB)

Morales, J.R.; Cancino, S. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago 1 (Chile); Miranda, P. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago 1 (Chile)], E-mail: pjmirand@gmail.com; Dinator, M.I. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Nunoa, Santiago 1 (Chile); Seelenfreund, A. [Universidad Academia de Humanismo Cristiano, Condell 343, Providencia, Santiago (Chile)

2007-11-15

Geochemical characterization studies using PIXE were carried out on 21 vitreous dacite artifacts from early formative archaeological sites in the Atacama region, in northern Chile, and on 13 samples taken from two potential volcanic sources located within the region. Performing statistical analyses it was possible to obtain elemental concentration patterns for the archaeological samples of this material and match some of these artifacts with the geological source samples.

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

Parasites of the flatfish Paralichthys adspersus (Steindachner, 1867 (Pleuronectiformes from northern Chile

Directory of Open Access Journals (Sweden)

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.

Large slope instabilities in Northern Chile and Southern Peru

Science.gov (United States)

Crosta, Giovanni B.; Hermanns, Reginald L.; Valbuzzi, Elena; Frattini, Paolo; Valagussa, Andrea

2014-05-01

Deep canyon incision into Tertiary paleosurfaces and large slope instabilities along the canyon flanks characterize the landscape of western slope of the Andes of northern Chile and South Peru. This area belongs to the Coastal Escarpment and Precordillera and is formed by coarse-grained clastic and volcanoclastic formations. The area is characterized by intense seismicity and long-term hyperaridity (Atacama Desert). Landslides along the canyon flanks affect volumes generally up to 1 km3 and locally evolved in large rock avalanches. We prepared a landslide inventory covering an area of about 30,000 km2, extending from Iquique (Chile) to the South and Tacna (Peru) to the North. A total of 606 landslides have been mapped in the area by use of satellite images and direct field surveys, prevalently including large phenomena. The landslides range from 1 10-3 km2 to 464 km2 (Lluta landslide). The total landslide area, inclusive of the landslide scarp and of the deposit, amounts to about 2,130 km2 (about 7% of the area). The mega landslides can be classified as large block slides that can evolve in large rock avalanches (e.g. Minimini landslide). Their initiation seems to be strongly associated to the presence of secondary faults and large fractures transversal to the slope. These landslides show evidence suggesting a re-incision by the main canyon network. This seems particularly true for the Lluta collapse where the main 'landslide' mass is masked or deleted by the successive erosion. Other landslides have been mapped along the Coastal Escarpment and some of the major tectonic escarpments with an E-W trend. We examined area-frequency distributions of landslides by developing logarithmically binned, non-cumulative size frequency distributions that report frequency density as a function of landslide planar area A. The size frequency distribution presents a strong undersampling for smaller landslides, due to the extremely old age of the inventory. For landslides larger than

Millennial-scale vegetation changes in the tropical Andes using ecological grouping and ordination methods

NARCIS (Netherlands)

Urrego, D.H.; Hooghiemstra, H.; Rama-Corredor, O.; Martrat, B.; Grimalt, J.O.; Thompson, L.; Bush, M.B.; González-Carranza, Z.; Hanselman, J.; Valencia, B.; Velásquez-Ruiz, C.

2016-01-01

We compare eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the last 30 000 years, with particular emphasis on the Pleistocene to Holocene transition. We explore ecological grouping and downcore

Los costos de la expedición militar a Chile, 1815-1818

Directory of Open Access Journals (Sweden)

Beatriz Bragoni

2016-09-01

Full Text Available Este trabajo explora las estrategias utilizadas para financiar la creación y el sostenimiento del Ejército de los Andes y los instrumentos fiscales utilizados para conseguirlo. El análisis de los distintos rubros que integraban las cajas del ejército permite examinar el peso de los recursos aportados por el gobierno central y por la jurisdicción cuyana. Asimismo, analiza el destino de los fondos a través del estudio de los presupuestos del ejército, con el objetivo de ponderar el peso que tuvieron los salarios en el total de los gastos militares durante la etapa previa al cruce de los Andes, y en la posterior, cuando el ejército estaba en Chile bajo severas condiciones fiscales de los gobiernos patriotas.

Monitoring rock glacier dynamics and ground temperatures in the semiarid Andes (Chile, 30°S)

Science.gov (United States)

Brenning, Alexander; Azócar, Guillermo F.; Bodin, Xavier

2013-04-01

Rock glaciers and mountain permafrost are widespread in the high semiarid Andes of Chile, where they concentrate greater amounts of ice than glaciers. Rock glaciers are of particular interest because in some cases the permafrost they contain might be in a degrading in response to climatic warming. This could result in increased dynamics and even to destabilization, which has been observed on some rock glaciers in the studied area. Displacement rates and active-layer temperatures of two rock glaciers as well as ground surface temperatures of the periglacial environment in the upper Elqui valley have been monitored since summer 2009/10 with funding from the Chilean Dirección General de Aguas. Differential GPS measurements of 115 points on the surface of two rock glaciers since April 2010 showed horizontal displacements of up to 1.3 m/a on the Llano de las Liebres rock glacier and up to 1.2 m/a on the Tapado rock glacier. General velocity patterns are consistent with the morphological evidence of activity (e.g., front slopes, looseness of debris) and for the Tapado complex, a clearly distinct activity from the debris-covered glacier was observed. Temperature measurements in four boreholes indicate active-layer depths of about 2.5 m at the highest locations on the Tapado rock glacier (~4400 m a.s.l.) and about 8 m near the front of the Llano rock glacier (3786 m a.s.l.). Spatial patterns of mean ground surface temperature (MGST) were analyzed with regards to influences of elevation, potential incoming solar radiation, location on ice-debris landforms (rock and debris-covered glaciers), and snow cover duration using linear mixed-effects models. While accounting for the other variables, sites with long-lasting snow patches had ~0.4°C lower MGST, and ice-debris landforms had ~0.4-0.6°C lower MGST than general debris surfaces, highlighting important local modifications to the general topographic variation of ground thermal conditions.

Distribution of greenhouse gases in hyper-arid and arid areas of northern Chile and the contribution of the high altitude wetland microbiome (Salar de Huasco, Chile).

Science.gov (United States)

Molina, Verónica; Eissler, Yoanna; Cornejo, Marcela; Galand, Pierre E; Dorador, Cristina; Hengst, Martha; Fernandez, Camila; Francois, Jean Pierre

2018-04-06

Northern Chile harbors different bioclimatic zones including hyper-arid and arid ecosystems and hotspots of microbial life, such as high altitude wetlands, which may contribute differentially to greenhouse gases (GHG) such as carbon dioxide (CO 2 ), methane (CH 4 ) and nitrous oxide (N 2 O). In this study, we explored ground level GHG distribution and the potential role of a wetland situated at 3800 m.a.s.l, and characterized by high solar radiation arid to hyper-arid zones. The microbiome from the water and sediments was described by high-throughput sequencing 16S rRNA and rDNA genes. The results indicate that GHG at ground level were variable along the elevation gradient potentially associated with different bioclimatic zones, reaching high values at the high Andean steppe and variable but lower values in the Atacama Desert and at the wetland. The water areas of the wetland presented high concentrations of CH 4 and CO 2 , particularly at the spring areas and in air bubbles below microbial mats. The microbial community was rich (> 40 phyla), including archaea and bacteria potentially active in the different matrices studied (water, sediments and mats). Functional microbial groups associated with GHG recycling were detected at low frequency, i.e., arid and arid areas of northern Chile are sites of GHG exchange associated with various bioclimatic zones and particularly in aquatic areas of the wetland where this ecosystem could represent a net sink of N 2 O and a source for CH 4 and CO 2 .

The Glaciation of the Ecuadorian Andes

Science.gov (United States)

Schubert, Carlos

This pleasing book fills the gap in the knowledge about Pleistocene and recent glaciation between Colombia and Peru. A significant amount of data exists already for Colombia and Venezuela and for Peru, Bolivia, and, particularly, Chile. Hastenrath has now given us a description of glaciers and glaciation underneath the equator in the Andes.The book begins with brief summaries of the physiography and the atmospheric circulation, which give the general setting of Ecuador. Then follow detailed descriptions of the glaciers and glacial morphology of all the important mountains of the Western and Eastern Cordilleras. These are well illustrated, and a particularly useful feature is the comparison of old photographs and paintings of glaciers with modern photographs, many taken by the author. All illustrate the spectacular retreat of the glaciers in the Ecuadorian Andes during the last century and correlate quite well with observations elsewhere. This retreat is snown quantitatively in Table 4, in terms of decrease in glacier-covered area since the glacial advance of moraine stage III. The area of present-day glaciers is about 10% of the area during that stage (compared with about 1.5% in the Sierra Nevada de Mérida, Venezuela). A series of maps show the glacial morphology of the mountains (unfortunately, some of the maps have been included within the binding, thus losing some information; they could have been reduced somewhat to fit a single page or, if too large, could have been included in the pocket, together with the map of Chimborazo-Carihuairazo).

EL ROL DEL ANTICICLÓN PACÍFICO EN LA CAÍDA DE NIEVE EN LOS ANDES ÁRIDOS

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Arnobio G. Poblete

2016-12-01

Full Text Available This article aims to study in depth the role the anticyclone subtropical eastern South Pacific (ASPSO on the nival precipitation in the arid Andes, its seasonal variability, fluctuations in the long and medium scale and associations with snowfall. For this reason, the incidence on the ratio of precipitation, the SST in the South Pacific Ocean, precipitable water, wind zonal, Radiation in Outgoing Long Wave and Omega were analyzed. The methodology consisted in the evaluation of the ASPSO through the definition of an index, based on Santiago de Chile (PSGO measured surface atmospheric pressure. This would allow its surveillance and the processing of its temporal behavior in the statistical analysis. The results showed significant time - space associations within the involved variables, which confirmed in all cases the negative impact of ASPSO related to snowfall in the Andes mountains. period 1909-2015.

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

Factors structuring the phytoplankton community in the upwelling site off El Loa River in northern Chile

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Herrera, Liliana; Escribano, Ruben

2006-06-01

Understanding processes affecting the structure of the autotrophic community in marine ecosystems is relevant because species-dependent characters may affect productivity and carbon fluxes of the ocean. In this work, we studied the influence of oceanographic variability on phytoplankton species composition at a coastal upwelling site off northern Chile. Four seasonal cruises carried out during 2003 off El Loa River (21°S) showed that upwelling occurs year-round supporting a large number of diatoms, dinoflagellates, naked nanoflagellates, and silicoflagellates. The analysis of species composition showed that changes in the structure of the autotrophic community are expressed both in abundance and in differences in species assemblages. These changes occurred not only over the seasonal scale but also over the spatial pattern of distribution, and they correlated well to temporal variability of upwelling and spatial variation of upwelling conditions over the cross-shelf axis. A K-means clustering and principal component analyses showed that species assemblages can be represented by few dominant species strongly coupled to alternate upwelling vs. non-upwelling conditions. Both conditions are well defined, and mostly explained by changes in depth of the upper boundary of the oxygen minimum zone (OMZ) (a prominent feature in northern Chile), surface temperature and water column stratification. Abundance of dominant phytoplankton species were strongly correlated to both OMZ depth and water column stratification. Processes through which OMZ depth might influence species abundance and composition are unknown, although they may relate to changes in redox conditions which affect the nutrient field. Another explanation may relate to changes in grazing pressure derived from the effect of low oxygen water on zooplankton vertical distribution.

Proximity to mining industry and respiratory diseases in children in a community in Northern Chile: A cross-sectional study.

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Herrera, Ronald; Radon, Katja; von Ehrenstein, Ondine S; Cifuentes, Stella; Muñoz, Daniel Moraga; Berger, Ursula

2016-06-07

In a community in northern Chile, explosive procedures are used by two local industrial mines (gold, copper). We hypothesized that the prevalence of asthma and rhinoconjunctivitis in the community may be associated with air pollution emissions generated by the mines. A cross-sectional study of 288 children (aged 6-15 years) was conducted in a community in northern Chile using a validated questionnaire in 2009. The proximity between each child's place of residence and the mines was assessed as indicator of exposure to mining related air pollutants. Logistic regression, semiparametric models and spatial Bayesian models with a parametric form for distance were used to calculate odds ratios and 95 % confidence intervals. The prevalence of asthma and rhinoconjunctivitis was 24 and 34 %, respectively. For rhinoconjunctivitis, the odds ratio for average distance between both mines and child's residence was 1.72 (95 % confidence interval 1.00, 3.04). The spatial Bayesian models suggested a considerable increase in the risk for respiratory diseases closer to the mines, and only beyond a minimum distance of more than 1800 m the health impact was considered to be negligible. The findings indicate that air pollution emissions related to industrial gold or copper mines mainly occurring in rural Chilean communities might increase the risk of respiratory diseases in children.

Distribution of Euphausia mucronata at the upwelling area of Peninsula Mejillones, northern Chile: The influence of the oxygen minimum layer

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Escribano, R.; Marin, V.; Irribarren, C.

2000-01-01

Analysis of zooplankton samples from 53 stations obtained around Peninsula Mejillones (Northern Chile), from two strata: 0-50 m and 150-200 m, during active upwelling in December 1996, allowed the study of horizontal and vertical distribution of Euphausia mucronata, endemic Krill of the Humboldt Current. Information from CTDO and a fluorometer was used to analyze the influence of oceanographic variables on distribution of E. mucronata. E. mucronata was found distributed all around the Peninsu...

Range expansion of Oligoryzomys longicaudatus (Rodentia, Sigmodontinae in Patagonian Chile, and first record of Hantavirus in the region Ampliación del rango de distribución de Oligoryzomys longicaudatus (Rodentia, Sigmodontinae en la Patagonia de Chile y primer registro de Hantavirus en la región

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SEBASTIÁN BELMAR-LUCERO

2009-06-01

Full Text Available At present, 20 species of Oligoryzomys (Rodentia, Sigmodontinae are recognized in the Neotropical region, most of them distinguished by their karyotypes, which fluctuates between 46-70 chromosomes. Two species are currently recognized in Chile, Oligoryzomys longicaudatus (Bennet, 1832; "colilargo" or the long-tailed pygmy rice rat; 2n = 56, which ranges from 27° to approximately 51° S, and O. magellanicus (Bennet, 1836; Magellanic pygmy rice rat; 2n = 54, south of 51° S in the Patagonian region of Chile and Argentina. As part of an ongoing research on the southern Patagonia of Chile, we report the results of small mammal samplings in six localities. We karyotyped 28 specimens and we also sequenced the hypervariable mtDNA region I in 22 individuals, aligning these sequences with an under development phylogeny of O. longicaudatus. We also evaluated the serology and viral charge in all captured specimens to detect the presence of antibodies to Andes virus (ANDV through Strip Immunoblot Assay (SIA, and of viral genome by RT-PCR. The results consistently showed that the karyotype of southern Patagonia specimens was 2n = 56, equal to that of O. longicaudatus, and that individuals from this area do not differentiate phylogenetically from those of the northern range of distribution. In addition, the serology showed the presence of antibodies IgG anti-ANDV and of viral genome in heart, kidney, spleen, and lungs of a single specimen of Oligoryzomys from the locality of Fuerte Bulnes in the Magallanes region. We conclude that all specimens trapped south of 51° S correspond to Oligoryzomys longicaudatus, thus expanding the distribution of this specie! from 51° to at least 55° S. The results also extended the disiribution of the Andes strain of Hantavirus to southernmost Patagonia.Actualmente se reconocen 20 especies de Oligoryzomys (Rodentia, Sigmodontinae en la región Neotropical, la mayoría de ellas distinguidas por sus cariotipos, los que fluct

The Lower Cretaceous Way Group of northern Chile: An alluvial fan-fan delta complex

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Flint, S.; Clemmey, H.; Turner, P.

1986-01-01

Alluvial fan sediments of the Lower Cretaceous Coloso Basin in northern Chile were deposited in a half-graben and derived from andesitic volcanics of a former island arc. Transport directions were towards the east, away from the present-day Peru-Chile trench. Grain flow, density modified grain flow and sheetflow processes were responsible for most of the sediment deposition with cohesive debris flows playing only a minor part. An early phase of conglomerate deposition (Coloso Formation) into a restricted basin records the transition from proximal fan facies with abundant grain flows and remobilized screes to mid-fan facies dominated by sheetflows. Stratiform copper mineralization near the top of the lower conglomerates is related to the unroofing of the Jurassic island arc. This mineralization comprises copper sulphide-cemented sands and gravels and formed by the reaction of mineralized detritus with diagenetic and hydrothermal solutions. A later phase of deposition (Lombriz Formation) includes sandstones, siltstones and conglomerates with a source area different from the Coloso Formation. This change in source may be related to strike-slip tectonics as the basin extended. The Lombriz conglomerates pass distally (eastwards) into red sandstones and purple siltstones with thin limestones deposited under marine conditions. This sequence is interpreted as a major fan delta complex. It passes conformably into marine carbonates of the Tableado Formation signifying the complete drowning of the basin in lower Cretaceous times.

Nitrous oxide and N-nutrient cycling in the oxygen minimum zone off northern Chile

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Farías, Laura; Paulmier, Aurélien; Gallegos, Mauricio

2007-02-01

Measurements of dissolved gases (O 2, N 2O), nutrients (NO 3-, NO 2-, PO 43-), and oceanographic variables were performed off northern Chile (˜21°S) between March 2000 and July 2004, in order to characterize the existing oxygen minimum zone (OMZ) and identify processes involved in N 2O cycling. Both N 2O and NO 3- displayed sharp, shallow peaks with concentrations of up to 124 nM (1370% saturation) and 26 μM, respectively, in association with a strong oxycline that impinges on the euphotic zone. NO 2- accumulation below the oxycline's base reached up to 9 μM. The vertical distribution of physical and chemical parameters and the existing relationships between apparent oxygen utilization (AOU), apparent N 2O production (ΔN 2O), and NO 3- revealed three main layers within the upper OMZ. The first layer, or the upper part of the oxycline, is located between the base of the mixed layer and the mid-point of the oxycline (around σ t=25.5 kg m -3). There the O 2 declines from ˜250 to ˜50 μM, and strong (but opposing) O 2 and NO 3- gradients and their associated AOU-ΔN 2O and AOU-NO 3- relationships indicate that nitrification produces N 2O and NO 3- in the presence of light. The second layer, or lower part of the oxycline, represents the upper OMZ boundary and is located between the middle and the base of the oxycline (25.926.2 kg m -3, which is typical of Equatorial Subsurface Water (ESSW). In this layer, N 2O and NO 3- continue to decrease, but a large NO 2- accumulation is observed. Considering all the data, a biogeochemical model for the upper OMZ off northern of Chile is proposed, in which nitrification and denitrification differentially mediate N 2O cycling in each layer.

Isotopic and Hydrogeochemical Techniques for the Sustainable Management of Water Resources in an Aridwater Shed of Northern Chile

Energy Technology Data Exchange (ETDEWEB)

Oyarzun, R. [Departamento Ingenieria de Minas, Universidad de La Serena and Centro de Estudios Avanzados en Zonas Aridas, La Serena (Chile); Oyarzun, J.; Maturana, H.; Jofre, E. [Departamento Ingenieria de Minas, Universidad de La Serena (Chile); Munoz, J. F.; Ortiz, C. [Departamento de Ingenieria Hidraulica y Ambiental, Pontificia Universidad Catolica (Chile); Aguirre, E.; Marin, S. [Comision Chilena de Energia Nuclear (Chile); Kretschmer, N. [Centro de Estudios Avanzados en Zonas Aridas, La Serena (Chile)

2013-07-15

Water is the main limiting factor for the development of Northern Chile. South of 26{sup o}S, major conflicts are related to the allocation of water and the interaction between surface and shallow groundwater, when used by farmers. The conflict is aggravated due to little knowledge about these interactions. Isotope techniques can add valuable information for the assessment of water interactions and the definition of suitable integrated watershed management strategies. This is pursued in the Limari basin within the ongoing CHI/8/029 project, mainly funded by the IAEA. (author)

Isotopic evolution of aqueous sulphate in northern Chile water

International Nuclear Information System (INIS)

Aravena, R.; Suzuki, O.; Fritz, P.; Pena, H.; Rauert, W.

1987-01-01

Full text: The extremely arid condition of northern Chile is the main obstacle to the present and future development of urban centres and economic activities in the region. The existing water resources are scarce. During the last decade, isotope techniques have been applied to investigate aspects such as the origin and residence time of the groundwater, these being extremely important for water development and water management. This paper presents 18 O and 34 S data in aqueous sulphate, as well as 18 O, 2 H, and 3 H from springs, rivers and groundwater samples of the Pampa del Tamarugal and Salar de Llamara basins. The principal aim of this study was to investigate the isotope evolution of the sulphate, the origin of the sulphur, the groundwater flow path, and the possibility of using the 18 O of the sulphate as a tracer for estimation of the residence time of the groundwater. Springs that have their recharge area in the high Altiplano (Salar del Huasco basin) show δ values between +5.0 per mille and +6.0 per mille for the 18 O and +5.0 per mille and +9.0 per mille for the 34 S isotope. Springs from lower altitude, show an isotope content between + 8.6 per mille and + 10.6 per mille for 18 O and +7.4 per mille and + 11.7 per mille for 34 S. The groundwaters in the Pampa aquifers, based on their hydrogen and oxygen isotope composition, are associated with different recharge areas. However, these waters show an isotope range for the sulphate similar to .he one of the springs, and no clear relationships are observed between isotope content, flow path and residence time. This pattern could be related to the poorly defined aquifer systems present in the Pampa. The Llamara groundwaters have a uniform isotope content and are the most enriched in the region (δ 18 O = -6.0 per mille and δ 2 H = -50 per mille). The isotope composition of their sulphate compares well with the Pampa groundwater, indicating a similar sulphate source. The isotope composition of gypsum

Ecology, Genetic Diversity, and Phylogeographic Structure of Andes Virus in Humans and Rodents in Chile▿

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Medina, Rafael A.; Torres-Perez, Fernando; Galeno, Hector; Navarrete, Maritza; Vial, Pablo A.; Palma, R. Eduardo; Ferres, Marcela; Cook, Joseph A.; Hjelle, Brian

2009-01-01

Andes virus (ANDV) is the predominant etiologic agent of hantavirus cardiopulmonary syndrome (HCPS) in southern South America. In Chile, serologically confirmed human hantavirus infections have occurred throughout a wide latitudinal distribution extending from the regions of Valparaíso (32 to 33°S) to Aysén (46°S) in southern Patagonia. In this study, we found seropositive rodents further north in the Coquimbo region (30°S) in Chile. Rodent seroprevalence was 1.4%, with Oligoryzomys longicaudatus displaying the highest seroprevalence (5.9%), followed by Abrothrix longipilis (1.9%) and other species exhibiting ≤0.6% seropositivity. We sequenced partial ANDV small (S) segment RNA from 6 HCPS patients and 32 rodents of four different species collected throughout the known range of hantavirus infection in Chile. Phylogenetic analyses showed two major ANDV South (ANDV Sout) clades, congruent with two major Chilean ecoregions, Mediterranean (Chilean matorral [shrubland]) and Valdivian temperate forest. Human and rodent samples grouped according to geographic location. Phylogenetic comparative analyses of portions of S and medium segments (encoding glycoproteins Gn and Gc) from a subset of rodent specimens exhibited similar topologies, corroborating two major ANDV Sout clades in Chile and suggesting that yet unknown factors influence viral gene flow and persistence throughout the two Chilean ecoregions. Genetic algorithms for recombination detection identified recombination events within the S segment. Molecular demographic analyses showed that the virus is undergoing purifying selection and demonstrated a recent exponential growth in the effective number of ANDV Sout infections in Chile that correlates with the increased number of human cases reported. Although we determined virus sequences from four rodent species, our results confirmed O. longicaudatus as the primary ANDV Sout reservoir in Chile. While evidence of geographic differentiation exists, a single

The pre-Columbian introduction and dispersal of Algarrobo (Prosopis, Section Algarobia) in the Atacama Desert of northern Chile

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Gayo, Eugenia M.; Santoro, Calogero M.; De Pol-Holz, Ricardo; Latorre, Claudio

2017-01-01

Archaeological and palaeoecological studies throughout the Americas have documented widespread landscape and environmental transformation during the pre-Columbian era. The highly dynamic Formative (or Neolithic) period in northern Chile (ca. 3700–1550 yr BP) brought about the local establishment of agriculture, introduction of new crops (maize, quinoa, manioc, beans, etc.) along with a major population increase, new emergent villages and technological innovations. Even trees such as the Algarrobos (Prosopis section Algarobia) may have been part of this transformation. Here, we provide evidence that these species were not native to the Atacama Desert of Chile (18–27°S), appearing only in the late Holocene and most likely due to human actions. We assembled a database composed of 41 taxon specific AMS radiocarbon dates from archaeobotanical and palaeoecological records (rodent middens, leaf litter deposits), as well an extensive bibliographical review comprising archaeobotanical, paleoecological, phylogenetic and taxonomic data to evaluate the chronology of introduction and dispersal of these trees. Although Algarrobos could have appeared as early as 4200 yr BP in northernmost Chile, they only became common throughout the Atacama over a thousand years later, during and after the Formative period. Cultural and natural factors likely contributed to its spread and consolidation as a major silvicultural resource. PMID:28742126

Floristic changes in alpine plant communities induced by the cushion plant Azorella madreporica (Apiaceae in the Andes of central Chile Cambios florísticos en comunidades de plantas alpinas inducidos por la planta en cojín Azorella madrepórica (Apiaceae en los Andes de Chile central

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CONSTANZA L QUIROZ

2009-06-01

Full Text Available It is well known that the number of plant species associated with nurse plants increases with elevation. However, studies conducted so far have largely ignored the effect of nurse plants on other community attributes, such as the species abundances, diversity and evenness. Moreover, changes in these community attributes along environmental gradients have also been seldom examined. The present study evaluates the effect of the cushion plant Azorella madrepórica (Apiaceae on species richness, species abundance, diversity and evenness of vascular plants at two elevations in the Andes of central Chile. Theoretically, the impact of this nurse cushion plant on these community attributes should be grater at a higher elevation. Results showed that the proportion of plant species associated with cushion plants increases with elevation, and the abundance of some species is also greater within cushions than on bare ground. Although the proportion of species growing within cushions increased with elevation, diversity and evenness were higher on bare ground. This is due to some few species that attained very high densities within cushions, generating assemblages highly dominated by some few species. Ordination analyses indicated differences in species assemblages within and outside A. madrepórica at the higher elevation. Therefore, the influence of cushion plants on community structure changes with elevation. Accordingly, we suggest that attributes other than species richness must be included in future studies in order to analyze the impact of nurse species on community structure along environmental gradients.Se sabe que el número de especies asociado a plantas nodrizas aumenta con la altitud. Sin embargo, el efecto de plantas nodrizas sobre otros atributos de las comunidades, como la abundancia de especies, diversidad y equidad, ha sido largamente ignorado. Más aún, cambios en estos atributos en gradientes ambientales han sido pocas veces examinados

Isotope hydrology and geochemistry of northern Chile groundwaters

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1995-01-01

no renovable. This paper reviews studies that applied isotope techniques in aquifers located in the Pampa del Tamarugal and the Salar de Atacama Basins in northern Chile. The main aims of these studies were to obtain information about the origin and residence time of groundwater, groundwater quality, evaporation rates from Salares, and the relationship between flooding and aquifer recharge. The main conclusions of these studies, that have implications for water resources management in this region are: a most of the groundwater is of good quality, with the exception of areas close to the Salares b a multiaquifer system was identified in the Pampa del Tamarugal basin, associated with recharge areas located at different altitudes and c a significant portion of the groundwaters in the Pampa aquifers should be treated as a non renewable water resource.

Diversity of the genus Polylepis (Rosaceae, Sanguisorbeae in the Peruvian Andes

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Wilfredo Mendoza

2011-08-01

Full Text Available This study provides information on the diversity of Peruvian species of Polylepis. Nineteen (19 species are reported here (more than 70% of the 27 species registered for the whole Andean region. As a result, Peru could be considered as the country with the largest diversity of Polylepis species, in comparison with Bolivia (13, Ecuador (7, Argentina (4, Colombia (3, Chile (2, and Venezuela (1. The species occur in 19 departments of Peru, with the majority of them in Cusco (10 and Ayacucho (8. Species diversity is mostly concentrated in the Peruvian southern Andes (15 species, with the region becoming the potential center of diversification of the genus Polylepis. Regarding their altitudinal distribution, the greatest diversity (18 is found between 3000 and 4000 m.

EL SECUESTRO DE LAS HISTORIAS INDÍGENAS: ITENERARIO Y LIMITACIONES DEL TIEMPO LINEAL EN CHILE

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MAXIMILIANO SALINAS CAMPOS

2015-01-01

Full Text Available La historia de Chile está cruzada por el conflicto entre la cultura moderna europea y las culturas indígenas. El tiempo lineal impuesto por el Estado nacional ha dejado al descubierto su irresponsabilidad con el tiempo indígena de los Andes. Esta temporalidad expresa una profunda y sustentable «ontología arcaica». Tras el fin de la Guerra Fría, y la postdictadura de Pinochet, esta propuesta se vuelve acuciante con las demandas políticas y los desafíos epistémicos indígenas del siglo XXI. En el «círculo de la vida» estos pueblos reclaman presencia, pasado y futuro: su historia. Este trabajo es resultado del proyecto de investigación de la Universidad de Santiago de Chile sobre la historia y la cultura de los pueblos indígenas en Chile en los siglos XX y XXI (Fondecyt 1121083, 2012-2014.

Saline-boron stress in northern Chile olive accessions: water relations, B and Cl contents and impact on plant growth

OpenAIRE

Escobar, Hugo; Lara, Nelson; Zapata, Yubinza; Urbina, Camilo; Rodriguez, Manuel; Figueroa, Leonardo

2013-01-01

H. Escobar, N. Lara, Y. Zapata, C. Urbina, M. Rodriguez, and L. Figueroa. 2013. Saline-boron stress in northern Chile olive accessions: water relations, B and Cl contents and impact on plant growth. Cien. Inv. Agr. 40(3): 597-607. The objective of this study was to analyze the effect of saline-boron stress on the vegetative growth, dry leaf weight, water potential (Ψw), relative water content, and leaf and root B and Cl- contents in 8 accessions of olive. Rooted one-year-old plants were culti...

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

Seasonal climatology of hydrographic conditions in the upwelling region off northern Chile

Science.gov (United States)

Blanco, J. L.; Thomas, A. C.; Carr, M.-E.; Strub, P. T.

2001-06-01

Over 30 years of hydrographic data from the northern Chile (18°S-24°S) upwelling region are used to calculate the surface and subsurface seasonal climatology extending 400 km offshore. The data are interpolated to a grid with sufficient spatial resolution to preserve cross-shelf gradients and then presented as means within four seasons: austral winter (July-September), spring (October-December), summer (January-March), and fall (April-June). Climatological monthly wind forcing, surface temperature, and sea level from three coastal stations indicate equatorward (upwelling favorable) winds throughout the year, weakest in the north. Seasonal maximum alongshore wind stress is in late spring and summer (December-March). Major water masses of the region are identified in climatological T-S plots and their sources and implied circulation discussed. Surface fields and vertical transects of temperature and salinity confirm that upwelling occurs year-round, strongest in summer and weakest in winter, bringing relatively fresh water to the surface nearshore. Surface geostrophic flow nearshore is equatorward throughout the year. During summer, an anticyclonic circulation feature in the north which extends to at least 200 m depth is evident in geopotential anomaly and in both temperature and geopotential variance fields. Subsurface fields indicate generally poleward flow throughout the year, strongest in an undercurrent near the coast. This undercurrent is strongest in summer and most persistent and organized in the south (south of 21°S). A subsurface oxygen minimum, centered at ˜250 m, is strongest at lower latitudes. Low-salinity subsurface water intrudes into the study area near 100 m, predominantly in offshore regions, strongest during summer and fall and in the southernmost portion of the region. The climatological fields are compared to features off Baja within the somewhat analogous California Current and to measurements from higher latitudes within the Chile

Antecedentes geobotánicos de una cuenca andina de Chile Central

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Quintanilla Pérez, V.

2004-12-01

Full Text Available Like any other mountain ecosystem; the Andes Mountains show an outstanding phytoecological specificity. This is because of the influence of ecological conditions; as well as the presence of special vegetation groups. These groups of plants show a well defined structure and functionality; arising from the adaptation of biological behavior to the regional altitude. Nevertheless; despite the rigourous climatic conditions; plants do have access to water supplies. A latitudinal vegetation distribution is proposed; based on three vegetation belts: montane; subandine and andine. A remarkable similarity can be noticed between the montane plant communities and those corresponding to the central lower valleys. In addition; the influence of geomorphological processes on plant life and its distribution is presented. Finally; a case study in the highlands of the Andes; Santiago de Chile; is discussed.

[fr] Comme tous les systèmes de montagne du monde; les Andes du Chili Central présentent une identité phytoécologique; qui se manifeste par l'action des conditions écologiques très particulières et par la présence de groupements végétaux qui montrent une individualité par rapport à ces caractères structurels et fonctionels; résultant de l'adaptation des plantes aux effets de l'altitude; avec des conditions climatiques difficiles; mais pourtant avec la possibilité de profiter des reserves du sol en eau. Dans ces montagnes on a établi une zonation en altitude; et on peut distinguer trois étages: montagnard; subandin et andin. Les seuils altimétriques des étages changent selon les versants; mais tous présentent une certaine richesse d'espèces endémiques. Cependant on remarque les ressemblances floristiques de l'étage montagnard avec les vallées centrales du pays. On présente aussi un aperçu des effets de la dynamique agressive des processus géomorphologiques de montagne sur la vie des plantes; avec une étude de cas dans les

Expanding Geophysical and Geochemical Investigation of Causes of Extraordinary Unrest at the Laguna del Maule (Rhyolitic) Volcanic Field, Southern Andes, Chile

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Singer, B. S.

2014-12-01

The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007 the crust here has been inflating at an astonishing rate of 25 cm/yr. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ~20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. Swarms of volcano-tectonic and long period earthquakes, mostly of M San Juan-Argentina, Nanyang Technological University-Singapore, SERNAGEOMIN, OVDAS, USGS, and SEGEMAR-Argentina. Team members will be introduced in this presentation. Our approach includes augmenting the OVDAS array of 6 permanent seisic stations with 40 additional instruments to conduct tomographic, receiver function and ambient noise studies. We continue to collect 4-D gravity data from 37 stations. Surface deformation is monitored via cGPS at 5 permanent receivers and InSAR data. A magnetotelluric survey across the Andes at 36o S is planned. Geochemical studies include mineral zoning and U-Th disequilibrium of zircons to constrain the timing of magma intrusion and mixing events prior to the current unrest. The overall aim is to integrate these observations and to construct numerical models of system dynamics. We are developing communications protocols and a web site to facilitate sharing of findings among the team members and with the public.

Latitudinal discontinuity in thermal conditions along the nearshore of central-northern Chile.

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Tapia, Fabian J; Largier, John L; Castillo, Manuel; Wieters, Evie A; Navarrete, Sergio A

2014-01-01

Over the past decade, evidence of abrupt latitudinal changes in the dynamics, structure and genetic variability of intertidal and subtidal benthic communities along central-northern Chile has been found consistently at 30-32°S. Changes in the advective and thermal environment in nearshore waters have been inferred from ecological patterns, since analyses of in situ physical data have thus far been missing. Here we analyze a unique set of shoreline temperature data, gathered over 4-10 years at 15 sites between 28-35°S, and combine it with satellite-derived winds and sea surface temperatures to investigate the latitudinal transition in nearshore oceanographic conditions suggested by recent ecological studies. Our results show a marked transition in thermal conditions at 30-31°S, superimposed on a broad latitudinal trend, and small-scale structures associated with cape-and-bay topography. The seasonal cycle dominated temperature variability throughout the region, but its relative importance decreased abruptly south of 30-31°S, as variability at synoptic and intra-seasonal scales became more important. The response of shoreline temperatures to meridional wind stress also changed abruptly at the transition, leading to a sharp drop in the occurrence of low-temperature waters at northern sites, and a concurrent decrease in corticated algal biomass. Together, these results suggest a limitation of nitrate availability in nearshore waters north of the transition. The localized alongshore change results from the interaction of latitudinal trends (e.g., wind stress, surface warming, inertial period) with a major headland-bay system (Punta Lengua de Vaca at 30.25°S), which juxtaposes a southern stretch of coast characterized by upwelling with a northern stretch of coast characterized by warm surface waters and stratification. This transition likely generates a number of latitude-dependent controls on ecological processes in the nearshore that can explain species

Karyotypic polymorphism and evolution within and between the Liolaemus monticola (Iguanidae "northern 2n = 38-40" chromosome race populations in central Chile Polimorfismo cromosómico y evolución intra e inter poblacional de la raza cromosómica "Norte 2n = 28-40" de Liolaemus monticola (Iguanidae en Chile Central

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MADELEINE LAMBOROT

2001-03-01

Full Text Available Chromosomal genotypes were scored from 359 Liolaemus monticola lizards of the "northern, 2n = 38-40" chromosomal race from 21 locality samples between the Maipo (and one of its tributaries and the Aconcagua (and one of its tributaries ribers, plus a sample from the interracial hybridization zone, and some representative locality samples of the "southern 2n = 34" and the "multiple fission 2n = 42-44" chromosomal races for comparisons. The first seven variable chromosomal pairs were coded as Mendelian genotypes and statistically summarized by several clustering and population genetic algorithms. Spatial and temporal differentiation was assessed by chromosome frequencies, chromosomal diversity and heterozygosity. While no differentiation was found for diversity in the "northern 2n = 38-40" race, chromosomal frequencies and heterozygosity showed significant spatial differentiation that permit distinguishing between the coastal, Andean and transversal mountain range populations. The sample of Cuesta Chacabuco may represent a hybrid zone between the other two range samples. The origin of the chromosomal rearrangements, the population cytogenetics, and the recombination patterns resulting from chromosomal heterozygosity are compared in these chromosomal races, thus expanding the geographical area. These patterns are discussed with respect to the evolution of this complex in Chile and the importance of the riverine barriers in central ChileSe cuantificaron los "genotipos" cromosómicos para 359 lagartijas de 21 muestras poblacionales de la raza "Norte, 2n = 38-40" comprendida entre los ríos: río Maipo y uno de sus afluentes el río Yeso y río Aconcagua (y uno de sus afluentes el río Juncal. Con fines comparativos agregamos una muestra de la zona de hibridación interracial, algunas muestras representativas de la raza "Sur 2n = 34" y una de la raza "múltiples fisiones 2n = 42-44". Los siete primeros pares cromosómicos variables fueron codificados

U-Pb and K-Ar geochronology from the Cerro Empexa Formation, 1st and 2nd Regions, Precordillera, northern Chile

International Nuclear Information System (INIS)

Tomlinson, A.J; Martin, M.W; Blanco, N.; Perez de Arce, C

2001-01-01

The Cerro Empexa Formation (Galli, 1957) is a regionally distributed andesitic volcanic and continental sedimentary unit exposed in the Precordillera of the 1st and 2nd Regions of northern Chile. The formation has generally been considered to lie within the Lower or 'mid' Cretaceous, however, this assignment is based on scant, unreliable geochronologic data. Furthermore, there are conflicting interpretations as to whether the unit predates or postdates the first major Mesozoic shortening event affecting northern Chile. Because of the formation's presumed mid-Cretaceous age and its stratigraphic position over older back-arc sedimentary successions, the unit has been interpreted to represent products of the first eastward jump in the Andean magmatic arc from the arc's initial position in the Cordillera de la Costa (Scheuber and Reutter, 1992). In this paper we present the results of mapping and field observations that indicate exposures previously assigned to the Cerro Empexa Formation include two andesitic volcanic units separated by a major unconformity. The Cerro Empexa Formation proper lies above this unconformity. We also present U-Pb zircon and K-Ar geochronology that indicate the Cerro Empexa Formation is latest Cretaceous in its lower levels, and integrate our data with previously reported 40 Ar/ 39 Ar and fission-track data in the Cerros de Montecristo area (Maksaev, 1990; Maksaev and Zentilli, 1999) to show that 1800±600 m of rocks were deposited within ca. 2.5 m.y (au)

The influence of acculturation strategies in quality of life by immigrants in Northern Chile.

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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.

Enriched Nitrate and Depleted Nitrite Isotopic Signatures in the OMZ off Northern Chile

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Bristow, L. A.; Altabet, M. A.; Stewart, F.; Delong, E.; Ulloa, O.

2010-12-01

The vast majority of fixed nitrogen loss from the ocean’s water-column occurs in the O2 minimum zones of the Arabian Sea and the eastern tropical North and South Pacific (ETNP and ETSP). In these regions, subsurface O2 concentrations reach suboxic levels that favor microbial production of N2 gas from combined N sources via heterotrophic denitrification and anammox. One of the most intense oxygen minimum zones (OMZ) is found in the ETSP, especially off northern Chile, where O2 depleted waters can reach into the photic zone as a result of coastal upwelling and a narrow continental shelf. Despite the importance of these regions there still remains much uncertainty about N cycling in these regions. We present δ15N and δ18O isotope data for nitrate and δ15N data for nitrite, which along with corroborating relative gene abundances from metagenomes provide insight into N-cycling processes both within and above the OMZ. Depth profiles showed some of the highest δ15N nitrate values seen to date in an OMZ (up to 32‰), which has implications for tracing denitrification related biogeochemical signals throughout the Pacific and for downcore recording of past changes in OMZ intensity. Co-occurring nitrite δ15N in the OMZ fell in the range -6 to -20‰, resulting in a δ15N offset between co-occurring nitrate and nitrite in the range 30 to 40‰. This offset is greater than that expected from heterotrophic denitrification alone, implying either a larger isotope effect for the first enzymatic step in denitrification (NO3- reduction to NO2-) than previously estimated from field and culture studies or, more likely, that additional processes are enhancing this separation. NO3- consumption by heterotrophic denitrification has been shown to increase both δ15N and δ18O of nitrate in a 1:1 ratio. The slope for samples in the OMZ off northern Chile show a clear but surprisingly negative deviation from the expected slope of 1, again suggesting additional processes are occurring

Hydrological Modeling of Highly Glacierized Basins (Andes, Alps, and Central Asia

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Nina Omani

2017-02-01

Full Text Available The Soil and Water Assessment Tool (SWAT was used to simulate five glacierized river basins that are global in coverage and vary in climate. The river basins included the Narayani (Nepal, Vakhsh (Central Asia, Rhone (Switzerland, Mendoza (Central Andes, Argentina, and Central Dry Andes (Chile, with a total area of 85,000 km2. A modified SWAT snow algorithm was applied in order to consider spatial variation of associated snowmelt/accumulation by elevation band across each subbasin. In previous studies, melt rates varied as a function of elevation because of an air temperature gradient while the snow parameters were constant throughout the entire basin. A major improvement of the new snow algorithm is the separation of the glaciers from seasonal snow based on their characteristics. Two SWAT snow algorithms were evaluated in simulation of monthly runoff from the glaciered watersheds: (1 the snow parameters are lumped (constant throughout the entire basin and (2 the snow parameters are spatially variable based on elevation bands of a subbasin (modified snow algorithm. Applying the distributed SWAT snow algorithm improved the model performance in simulation of monthly runoff with snow-glacial regime, so that mean RSR decreased to 0.49 from 0.55 and NSE increased to 0.75 from 0.69. Improvement of model performance was negligible in simulations of monthly runoff from the basins with a monsoon runoff regime.

Andes: An Intelligent Homework System for Introductory Physics

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van de Sande, Brett; VanLehn, K.; Hausmann, R.; Treacy, D.; Shelby, R.

2006-12-01

We know that students benefit from solving homework problems under the guidance of an expert (human) tutor. The Andes system (http://www.andes.pitt.edu) is designed for students to solve homework problems under the guidance of an expert computer tutor. Andes encourages students to use sound problem solving techniques and provides immediate right/wrong feedback on each step of a solution. On request, Andes also provides hints based on previous student actions. I will discuss how Andes works, from a student's perspective, and summarize research that demonstrates its effectiveness as a pedagogical tool. I will also discuss how Andes can function as a tool for conducting educational research, presenting an investigation of students' hint usage as an example.

Protection of Existing and Potential Astronomical Sites in Chile - an Update.

Science.gov (United States)

Smith, M. G.; Sanhueza, P.; Norman, D.; Schwarz, H.; Orellana, D.

2002-12-01

The IAU's Working Group on Controlling Light Pollution (iauwg) has declared Mauna Kea and a wide strip of Northern Chile between Antofagasta and Chajnanator as top priorities for its efforts to protect existing and potential sites in the Northern and Southern hemispheres respectively. This report provides an update on the iauwg's co-ordinated efforts to protect areas around the major international optical observatories in Chile, as well as the "Chilean Special Zone" (CSZ) mentioned above. This zone is of current and potential interest for the installation of extremely large optical telescopes and includes the ALMA radio-astronomy site. The CSZ is potentially vulnerable to adverse effects of mining in the region. Progess has been made in demonstrating to local mining interests within the CSZ the economic advantages of quality lighting. Educational and outreach activities to a variety of target audiences are building on legislation covering dark skies - itself part of work by the Chilean government to protect the natural heritage of Chile. Substantial good will was generated by an international, bilingual conference held last March in Chile. Just in the region around AURA's Observatory in Chile (Gemini South, CTIO and SOAR), a portable planetarium has been used to reach out to over 600 teachers and 65,000 pupils in the RedLaSer schools network within the last three years. This has attracted the direct interest of Chile's Ministry of Education. Videoconferencing over Internet2 is being used for educational purposes between Chile and various sites in the US. The NSF- initiated Mamalluca municipal observatory now receives more visitors than all the international observatories in Chile combined and is the focus of an expanding local industry of astronomical eco-tourism. Most of this work was supported by funding from, or via, the US NSF through CTIO and Gemini, and from ESO, OCIW, CONAMA and the IDA.

A Million-Year Record of Glaciation in the Tropical Andes

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Smith, J. A.; Seltzer, G. O.; Rodbell, D. T.; Farber, D. L.; Finkel, R. C.

2004-12-01

We present a longterm record of glaciation in the tropical Andes based on cosmogenic dating (10Be) of boulders on moraines. Well-preserved moraines in deglaciated valleys bordering the Junin Plain in central Peru ( ˜11° S, 76° W, 4000 m) were deposited during several glacial cycles extending back more than one million years before present (1 Myr BP). The presence of boulders with zero-erosion 10Be exposure ages >1 Myr constrains boulder erosion rates to relatively low values. For boulders at high altitudes, however, even low boulder erosion rates (0.3 to 0.5 m/Myr) make calculated old exposure ages markedly older [e.g., ˜20% older for a zero-erosion age of 400,000 10Be years (400 10Be kyr)]. Exposure ages recalculated with boulder erosion rates of 0.3 m/Myr straddle interglacial marine isotope stage (MIS) 11 ( ˜430-390 kyr BP), fall within glacial MIS 12 ( ˜480-430 kyr BP), but skip over glacial MIS 16 ( ˜670-630 kyr BP), perhaps the largest ice volume of the past 2 Myr. Increasing the erosion rate used in the calculations to 0.5 m/Myr moves ages into both MIS 11 and MIS 16. If we assume that the older Andean glaciations were indeed synchronous with global ice volume, our data suggest that boulder preservation cannot be treated as a simple linear process. Conversely, the data may be suggesting correctly that glaciation of the tropical Andes was not synchronous with the global glaciations as inferred from the marine isotope record. Our chronology for the last glacial maximum (LGM) in the region supports the idea of asynchrony between the global ice volume record and the terrestrial record of glaciation in the tropical Andes. The LGM in the Junin region of Peru and in the Cordillera Real of Bolivia (16° S 68° W) occurred ˜34 to 22 10Be kyr BP and was less extensive than older glaciations. Asynchrony between the LGM in the Northern Hemisphere ( ˜21 kyr BP) and the tropical Andes suggests that previous glaciations in the tropical Andes may have been

A further contribution to the knowledge of two inadequately known species of geophilid centipedes from the Andes of South-Central Chile, currently assigned to the genus Plateurytion Attems, 1909 (Chilopoda: Geophilomorpha).

Science.gov (United States)

Pereira, Luis Alberto

2015-10-06

Two poorly known species of geophilid centipedes from the Andes of South-Central Chile, i.e., Plateurytion mundus (Chamberlin, 1955) and Plateurytion zapallar (Chamberlin, 1955) (Myriapoda: Chilopoda: Geophilomorpha), are herein redescribed and illustrated after type specimens of both taxa and new material of the latter, rectifying the condition of the coxosternites of the second maxillae, which are medially joined through a narrow, hyaline and non-areolate membranous isthmus only (instead of "broadly fused as in Pachymerium", as stated by Chamberlin), this being consistent with the current generic assignment of these species under Plateurytion Attems, 1909. New data on many morphological features of specific value, until now unknown, are also given for both taxa. Plateurytion zapallar is reported for the first time from Coquimbo region, 11 Km N of Los Vilos (Elqui province), Valparaíso region, Quebrada Huaquén, Pichicuy (Petorca province), La Campana National Park (Quillota province), and Quebrada el Tigre, Cachagua (Valparíso province). A key for identification of the South American species currently included in Plateurytion is given.

Analysis of benthic macroinvertebrates and biotic indices to evaluate water quality in rivers impacted by mining activities in northern Chile

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Alvial I.E.

2013-02-01

Full Text Available Catchments in the semiarid regions are especially susceptible to environmental perturbation associated with water scarcity, hydrological variations and overuse by anthropogenic activities. Using multivariate analysis to relate environmental and biological data, and diversity and biotic indices (ChBMWP, ChIBF, we analyzed the macroinvertebrate composition of 12 rivers of the semiarid region of northern Chile. A non-metric multidimensional scaling for macroinvertebrate taxa and a principal component analysis for environmental variables strongly separated upstream sites (e.g. Vacas Heladas and Malo Rivers, which presented low pH and high dissolved metal concentrations, from other sites. Effectively, CCA showed that metals and low pH, associated with the altitudinal gradient, determined the distributional patterns of macroinvertebrates in the Elqui catchment. The causes of these particular conditions could be related to geological processes and human impact. The biotic indices applied to the sampling sites corroborated and reflected these characteristics, with La Laguna and Turbio Rivers showing a diverse macroinvertebrate community and moderate to good water quality, and the Claro River showing favorable conditions for the development of aquatic biota, indicating its better quality relative to other stations. To the middle and low part of the basin, a change in the composition of the community was observed, with species that suggest an impact by an increase in organic matter, due to agricultural activities and urban settlements concentrated in this area. Our results suggest that macroinvertebrate taxa in northern Chile may be exceptional species, adapted to unfavorable geochemical conditions, and emphasize the need for protection of the semiarid basins of the region.

Cobre labrado, alambique y aguardiente. Chile y Argentina, 1586-1850

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Pablo Lacoste

2016-01-01

Full Text Available El estudio examina el desarrollo de la producción, transporte y distribu- ción de cobres labrados y alambiques para elaborar aguardiente en Chile y el oeste de la actual Argentina, desde el primer alambique registrado (1586 hasta mediados del siglo XIX. Se detecta que el principal polo de manufactura de estos artefactos se encontraba en el Norte Chico de Chile, entre Huasco y La Serena. Desde allí, el uso de los alambiques se difundió por un amplio espacio. La ruta del alambique y el cobre labrado se extendió por 5.000 kilómetros, llegando a Guayaquil, Trujillo, Callao, Cinti, Jujuy y Salta por el norte; y a Valdivia y Chiloé por el sur, a ambos lados de la cordillera de los Andes. Floreció así un intenso proceso de integración socioeconómica regional, a la vez que se fortaleció el desa- rrollo agroindustrial con la posibilidad de destilar aguardientes. De esta manera se sentaron las bases para el surgimiento de varios productos típicos.

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 �

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 Lautaro Basin: A record of inversion tectonics in northern Chile La Cuenca Lautaro: un registro de inversión tectónica en el norte de Chile

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Fernando Martínez

2012-05-01

Full Text Available The Triassic and Jurassic tectonic history of northern Chile has been dominated by extension, although clear evidence about the nature and geometry of the extensional basins and subsequent inversion structures has been adequately illustrated in only a few cases. In this contribution we present a structural study of the Lautaro Basin located at the western edge of the Frontal Cordillera in the Atacama region of northern Chile. The Lautaro Basin is a Jurassic half-graben, filled by at least 2,600 m of marine deposits of the Lautaro Formation and developed on top of, at least 2,000 m of Triassic volcanic successions of the La Ternera Formation, also accumulated during an earlier period of extensional deformation. Detailed field mapping and construction of a regional balanced cross-section, supported by good exposures along the Copiapó River valley, allow reconstruction of the structural style of both the Jurassic and Triassic extensional depocenters. New structural data have shown that the Lautaro Basin has a complex structural framework reflected in two major Mesozoic extensional periods, overprinted by Cenozoic inversion involving thin- and thick-skinned tectonics. Shortening was accommodated by a combination of inversion of pre-existing normal faults, buttresses, development of footwall short-cuts, and both thin and thick-skinned thrusting. New estimates of shortening are up to 13.1 km (30%, while Mesozoic extension is estimated to be 3 km (7%.Durante el Triásico y Jurásico la evolución tectónica del norte de Chile fue dominada por extensión cortical. No obstante, evidencias claras acerca del estilo estructural y subsecuente inversión de las cuencas asociadas con el evento extensional, han sido ilustradas en pocos casos. En este trabajo, se presenta un estudio estructural de la Cuenca Lautaro, localizada en el borde occidental de la Cordillera Frontal, en la región de Atacama del norte de Chile. La Cuenca Lautaro, es un hemigraben que

Phytogeography of the vascular páramo flora of Ramal de Guaramacal (Andes, Venezuela) and its ties to other páramo floras

OpenAIRE

Cuello, N.L.; Cleef, A.M.; Aymard, G.

2010-01-01

Ramal de Guaramacal is an outlier and lower elevation mountain range located at the northeastern end of the Venezuelan Andes. Phytogeographical patterns and affinities of the low altitude and wet vascular páramo flora of Ramal de Guaramacal, have been studied with emphasis in to the analysis of the floristic connections of the Guaramacal páramo flora with the neighboring dry páramos of the Sierra Nevada de Mérida and other páramo floras of the northern Andes and Central America. A total of 25...

Unveiling current Guanaco distribution in chile based upon niche structure of phylogeographic lineages: Andean puna to subpolar forests.

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Benito A González

Full Text Available Niche description and differentiation at broad geographic scales have been recent major topics in ecology and evolution. Describing the environmental niche structure of sister taxa with known evolutionary trajectories stands out as a useful exercise in understanding niche requirements. Here we model the environmental niche structure and distribution of the recently resolved phylogeography of guanaco (Lama guanicoe lineages on the western slope of the southern Andes. Using a maximum entropy framework, field data, and information on climate, topography, human density, and vegetation cover, we identify differences between the two subspecies (L.g.cacsilensis, L.g.guanicoe and their intermediate-hybrid lineage, that most likely determine the distribution of this species. While aridity seems to be a major factor influencing the distribution at the species-level (annual precipitation <900 mm, we also document important differences in niche specificity for each subspecies, where distribution of Northern lineage is explained mainly by elevation (mean = 3,413 m and precipitation seasonality (mean = 161 mm, hybrid lineage by annual precipitation (mean = 139 mm, and Southern subspecies by annual precipitation (mean = 553 mm, precipitation seasonality (mean = 21 mm and grass cover (mean = 8.2%. Among lineages, we detected low levels of niche overlap: I (Similarity Index = 0.06 and D (Schoener's Similarity Index = 0.01; and higher levels when comparing Northern and Southern subspecies with hybrids lineage ( I = 0.32-0.10 and D = 0.12-0.03, respectively. This suggests that important ecological and/or evolutionary processes are shaping the niche of guanacos in Chile, producing discrepancies when comparing range distribution at the species-level (81,756 km(2 with lineages-level (65,321 km(2. The subspecies-specific description of niche structure is provided here based upon detailed spatial distribution of the lineages of guanacos in Chile. Such description

Importance of water quality on plant abundance and diversity in high-alpine meadows of the Yerba Loca Natural Sanctuary at the Andes of north-central Chile Importancia de la calidad del agua sobre la abundancia y diversidad vegetal en vegas altoandinas del Santuario Natural Yerba Loca en los Andes de Chile centro-norte

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ROSANNA GINOCCHIO

2008-12-01

Full Text Available Porphyry Cu-Mo deposits have influenced surface water quality in high-Andes of north-central Chile since the Miocene. Water anomalies may reduce species abundance and diversity in alpine meadows as acidic and metal-rich waters are highly toxic to plants The study assessed the importance of surface water quality on plant abundance and diversity in high-alpine meadows at the Yerba Loca Natural Santuary (YLNS, central Chile (33°15' S, 70°18' W. Hydrochemical and plant prospecting were carried out on Piedra Carvajal, Chorrillos del Plomo and La Lata meadows the growing seasons of 2006 and 2007. Direct gradient analysis was performed through canonical correspondence analysis (CCA to look for relationships among water chemistry and plant factors. High variability in water chemistry was found inside and among meadows, particularly for pH, sulphate, electric conductivity, hardness, and total dissolved Cu, Zn, Cd, Pb and Fe. Data on species abundance and water chemical factors suggests that pH and total dissolved Cu are very important factor determining changes in plant abundance and diversity in study meadows. For instance, Festuca purpurascens, Colobanthus quitensis, and Arenaria rivularis are abundant in habitals with Cu-rich waters while Festuca magellanica, Patosia clandestina, Plantago barbata, Werneria pygmea, and Erigeron andícola are abundant in habitals with dilute waters.Los megadepósitos de pórfidos de Cu-Mo han influido sobre la calidad de las aguas superficiales en las zonas altoandinas del centro-norte de Chile desde el Mioceno. Estas alteraciones en la calidad de las aguas podrían afectar negativamente a la vegetación presente en las vegas altoandinas, ya que las aguas acidas y ricas en metales son altamente tóxicas para las plantas. En este estudio se evaluó el efecto de la calidad de las aguas en la abundancia y diversidad florística de las vegas altoandinas del Santuario de la Naturaleza Yerba Loca (SNYL, en Chile central (33

Variability of 14C reservoir age and air-sea flux of CO2 in the Peru-Chile upwelling region during the past 12,000 years

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Carré, Matthieu; Jackson, Donald; Maldonado, Antonio; Chase, Brian M.; Sachs, Julian P.

2016-01-01

The variability of radiocarbon marine reservoir age through time and space limits the accuracy of chronologies in marine paleo-environmental archives. We report here new radiocarbon reservoir ages (ΔR) from the central coast of Chile ( 32°S) for the Holocene period and compare these values to existing reservoir age reconstructions from southern Peru and northern Chile. Late Holocene ΔR values show little variability from central Chile to Peru. Prior to 6000 cal yr BP, however, ΔR values were markedly increased in southern Peru and northern Chile, while similar or slightly lower-than-modern ΔR values were observed in central Chile. This extended dataset suggests that the early Holocene was characterized by a substantial increase in the latitudinal gradient of marine reservoir age between central and northern Chile. This change in the marine reservoir ages indicates that the early Holocene air-sea flux of CO2 could have been up to five times more intense than in the late Holocene in the Peruvian upwelling, while slightly reduced in central Chile. Our results show that oceanic circulation changes in the Humboldt system during the Holocene have substantially modified the air-sea carbon flux in this region.

A 22,000-Year Record of Monsoonal Precipitation from Northern Chile's Atacama Desert.

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Betancourt; Latorre; Rech; Quade; Rylander

2000-09-01

Fossil rodent middens and wetland deposits from the central Atacama Desert (22 degrees to 24 degrees S) indicate increasing summer precipitation, grass cover, and groundwater levels from 16.2 to 10.5 calendar kiloyears before present (ky B.P.). Higher elevation shrubs and summer-flowering grasses expanded downslope across what is now the edge of Absolute Desert, a broad expanse now largely devoid of rainfall and vegetation. Paradoxically, this pluvial period coincided with the summer insolation minimum and reduced adiabatic heating over the central Andes. Summer precipitation over the central Andes and central Atacama may depend on remote teleconnections between seasonal insolation forcing in both hemispheres, the Asian monsoon, and Pacific sea surface temperature gradients. A less pronounced episode of higher groundwater levels in the central Atacama from 8 to 3 ky B.P. conflicts with an extreme lowstand of Lake Titicaca, indicating either different climatic forcing or different response times and sensitivities to climatic change.

Las sociedades anónimas cruzan los Andes: los inversores chilenos en Neuquén al comenzar el siglo XX

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Graciela Blanco

2012-08-01

Full Text Available El territorio de Neuquén, en el norte de la Patagonia, atrajo la mirada de diversos inversores privados a partir del avance militar que realizó el Estado nacional sobre los grupos indígenas y de la conquista de las tierras del sur argentino; tierras que fueron ofrecidas a particulares en propiedad o arrendamiento en condiciones muy beneficiosas. Este trabajo analiza la conformación en Chile, en los primeros años del siglo XX, de sociedades anónimas que explicitaban como objetivo central la intención de comprar tierras a ambos lados de la Cordillera de los Andes para la explotación agroganadera y la comercialización, y estudia específicamente el origen, itinerario y organización productiva de una de esas sociedades en Neuquén.Neuquen territory, in the north of the Patagonia, attracted the look of diverse investors after from the military advance that realized the national State on the indigenous groups and of the conquest of the lands of the Argentine's south, lands that were offered to individuals in property or lease in very beneficial conditions. This work analyzes the conformation in Chile, in the first years of the 20th century, of joint-stock companies that stated explicitly as central aim the intention of buying lands on both sides of the Mountain chain of the Andes for the agricultural and livestock exploitation and the commercialization, and there studies specifically the origin, itinerary and productive organization of one of these companies in Neuquen.

Imaging and Understanding Foreshock and Aftershock Behavior Around the 2014 Iquique, Northern Chile, Earthquake

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Yang, H.; Meng, X.; Peng, Z.; Newman, A. V.; Hu, S.; Williamson, A.

2014-12-01

On April 1st, 2014, a moment magnitude (MW) 8.2 earthquake occurred offshore Iquique, Northern Chile. There were numerous smaller earthquakes preceding and following the mainshock, making it an ideal case to study the spatio-temporal relation among these events and their association with the mainshock. We applied a matched-filter technique to detect previously missing foreshocks and aftershocks of the 2014 Iquique earthquake. Using more than 900 template events recorded by 19 broadband seismic stations (network code CX) operated by the GEOFON Program of GFZ Potsdam, we found 4392 earthquakes between March 1st and April 3rd, 2014, including more than 30 earthquakes with magnitude larger than 4 that were previously missed in the catalog from the Chile National Seismological Center. Additionally, we found numerous small earthquakes with magnitudes between 1 and 2 preceding the largest foreshock, an MW 6.7 event occurring on March 16th, approximately 2 weeks before the Iquique mainshock. We observed that the foreshocks migrated northward at a speed of approximately 6 km/day. Using a finite fault slip model of the mainshock determined from teleseismic waveform inversion (Hayes, 2014), we calculated the Coulomb stress changes in the nearby regions of the mainshock. We found that there was ~200% increase in seismicity in the areas with increased Coulomb stress. Our next step is to evaluate the Coulomb stress changes associated with earlier foreshocks and their roles in triggering later foreshocks, and possibly the mainshock. For this, we plan to create a fault model of the temporal evolution of the Coulomb behavior along the interface with time, assuming Wells and Coppersmith (1994) type fault parameters. These results will be compared with double-difference relocations (using HypoDD), presenting a more accurate understanding of the spatial-temporal evolution of foreshocks and aftershocks of the 2014 Iquique earthquake.

Stable isotope tracers of water vapor sources in the Atacama Desert, Northern Chile: a pilot study on the Chajnantor Plateau

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Samuels, K. E.; Galewsky, J.; Sharp, Z. D.; Rella, C.; Ward, D.

2010-12-01

Subtropical deserts form in response to the interaction of large-scale processes, including atmospheric circulation and oceanic currents, with local features like topography. The degree to which each of these factors controls desert formation and the anticipated impacts of variations in each as climate changes, however, are poorly understood. Stable isotope compositions of water vapor in desert air can help to distinguish between moisture sources and processes that control aridity. The Atacama Desert, located in northern Chile between latitudes 23S and 27S, provides a natural laboratory in which to test the degree to which water vapor isotopologues enable the distinction between processes that control humidity, including the Hadley Circulation, the cold Humboldt Current off the coast of Chile, and the orographic effect of the Andes, in this subtropical desert. Water vapor isotopologues and concentrations were measured in real time using a cavity-ringdown spectrometer deployed on the Chajnantor Plateau over a three-week period from mid-July early August 2010. The elevation of the Plateau, 5000 m amsl (~550 hPa), places it above the boundary layer, allowing the evaluation of the Rayleigh fractionation model from the coast inland. Values reported by the instrument were verified with air samples taken at the coast and the Plateau, which were analyzed on an MAT-252 mass spectrometer. Water vapor concentrations and δD values varied spatially and temporally. Water vapor concentrations on the Plateau ranged from 200 to 3664 ppmv with a mean value of 536 ppmv. In contrast, water vapor concentrations at the coast were approximately 10000 ppmv, and at Yungay, 60 km inland, water vapor concentrations ranged from 1300 to 2000 ppmv from morning to evening. δD values on the Plateau ranged from -526‰ to -100‰ with a mean value of 290‰ with enriched values correlated to periods with higher water vapor concentrations. There are no strong diurnal variations in water vapor

Enfermedad de Chagas en poblaciones prehistóricas del norte de Chile Chagas disease in prehistoric populations of northern Chile

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NANCY ORELLANA-HALKYER

2010-12-01

Full Text Available La enfermedad de Chagas es producida por el parásito Trypanosoma cruzi, el cual afecta tanto a seres humanos como a animales, en particular mamíferos marsupiales y placentarios. Las vías de transmisión son diversas, siendo una de las más importantes la vía vectorial, en la que participan insectos infectados con este parásito, animales y humanos. En este artículo de revisión discutimos los postulados sobre la vía de transmisión oral, los hallazgos de T. cruzi en momias de América y especialmente en las del norte de Chile. Presentamos además información que apunta a que la enfermedad de Chagas estuvo presente mucho antes de la conquista europea y de la construcción de viviendas de adobe. Comentamos las hipótesis sobre el vector domiciliado más importante de Sudamérica, Triatoma infestans, su antigüedad en la costa de Arica y los reportes más recientes de otros vectores silvestres. También se discute la información relacionada a la participación en el ciclo de T. cruzi de distintos mamíferos silvestres de Chile y asimismo proponemos el estudio paleoparasitológico en restos zooarqueológicos para conocer las especies de mamíferos reservónos de T. cruzi en la antigüedad.Chagas diseases is produced by a parasite named Trypanosoma cruzi, that affects humans and other marsupial and placental mammals. Transmission routes are diverse, but the most important transmission is the vector route, which involves the triatomine insects, wild and domestic infected animáis, and humans. Here we review the data about oral transmission route and the evidences of the etiological agent (Trypanosoma cruzi of Chagas disease in pre-Columbian American mummies, making a critical review of the infection in northern Chile. Moreover, we comment on the hypotheses suggested in relation to the most important vector of the infection in South América Triatoma infestans, its antiquity in the Arica coast, and the recent reports about other wild infected

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.

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

An Analysis of Mass Balance of Chilean Glaciers

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Ambinakudige, S.; Tetteh, L.

2013-12-01

Glaciers in Chile range from very small glacierets found on the isolated volcanoes of northern Chile to the 13,000 sq.km Southern Patagonian Ice Field. Regular monitoring of these glaciers is very important as they are considered as sensitive indicators of climate change. Millions of people's lives are dependent on these glaciers for fresh water and irrigation purpose. In this study, mass balances of several Chilean glaciers were estimated using Aster satellite images between 2007 and 2012. Highly accurate DEMs were created with supplementary information from IceSat data. The result indicated a negative mass balance for many glaciers indicating the need for further monitoring of glaciers in the Andes.

Geomorphological characterization of endorheic basins in northern Chile

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Dorsaz, J.; Gironas, J. A.; Escauriaza, C. R.; Rinaldo, A.

2011-12-01

Quantitative geomorphology regroups a large number of interesting tools to characterize natural basins across scales. The application of these tools to several river basins allows the description and comparison of geomorphological properties at different spatial scales as oppose to more traditional descriptors that are typically applied at a single scale, meaning the catchment scale. Most of the recent research using these quantitative geomorphological tools has focused on open catchments and no specific attention has been given to endorheic basins, and the possibility of having particular features that distinguish them from exorheic catchments. The main objective of our study is to characterize endorheic basins and investigate whether these special geomorphological features can be identified. Because scaling invariance is a widely observed and relatively well quantified property of open basins, it provides a suitable tool to characterize differences between the geomorphology of closed and open basins. Our investigation focuses on three closed basins located in northern Chile which describe well the diversity in the geomorphology and geology of this arid region. Results show that endhoreic basins exhibit different slope-area and flow paths sinuosity regimes compared to those observed in open basins. These differences are in agreement with the particular self-similar behavior across spatial scales of the Euclidean length of subcatchments, as well as the Hack's law and Horton's ratios. These regimes imply different physical processes inside the channel network regardless of the basin area, and they seem to be related to the endorheic character of these basins. The analysis of the probability density functions of contributing areas and lengths to the lower region shows that the hypothesis of self-similarity can also be applied to closed basins. Theoretical expressions for these distributions were derived and validated by the data. Future research will focus on (1

Metazoan parasite fauna of the bigeye flounder, Hippoglossina macrops, from Northern Chile. Influence of host age and sex

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González M Teresa

2001-01-01

Full Text Available The metazoan parasite fauna of Hippoglossina macrops (n = 123 from northern Chile (30°S is quantitatively described for the first time, and the role of host age and sex was evaluated. Twelve parasite species were recovered, including 5 ectoparasites (2 Monogenea, 2 Copepoda and 1 Piscicolidae and 7 endoparasites (1 Digenea, 3 Cestoda, 2 Acanthocephala, and 1 Nematoda. The copepod Holobomolochus chilensis, the monogenean Neoheterobothrium sp., the adult acanthocephalan Floridosentis sp. and the hirudinean, Gliptonobdella sp. are new geographical and host records. The most prevalent ectoparasitic species were the monogenean, Neoheterobothrium sp. and the copepod, H. chilensis. Among endoparasites, the acanthocephalans Floridosentis sp. and Corynosoma australe were most prevalent and abundant. Prevalence and mean intensity of infection for most parasitic species were not affected by host sex, however the prevalence of Floridosentis sp. was significantly greater in males. Intensity of infection was positively correlated with host age for Neoheterobothrium sp., and negatively correlated for Floridosentis sp. and H. chilensis. The helminth species richness of the host H. macrops was lower compared to related flatfishes from the Northern Hemisphere. The relationship of the helminth fauna of H. macrops, its feeding habits and ecological habitats are discussed.

Hydrogeomorphic Investigation of the 2015 Atacama Floods, Northern Chile

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Wilcox, A. C.; Escauriaza, C. R.; Agredano, R., Jr.; Mignot, E.; Gironas, J. A.; Cienfuegos, R.; Mao, L.

2015-12-01

In March 2015 unusual atmospheric conditions over the Atacama Desert of northern Chile, the driest area on Earth outside of Antarctica, produced many years worth of rainfall in a 24-hour period. The resulting sediment-rich floods caused dozens of deaths and/or disappearances, over $1 billion in estimated damage, and widespread geomorphic change. Here we describe the hydrologic and geomorphic drivers and responses to the 2015 Atacama floods, including characterization of the hydrologic forcing, water and sediment routing from source areas in the upper watershed to the outlet at the Pacific Ocean, and urban flooding impacts of this event. In a region where few direct measurements of precipitation and discharge during these events are available, we combined hydrologic and hydraulic modeling with field and aerial photograph interpretation of sediment sources and geomorphic change. A remarkable element of the flood, particularly with respect to its effects on urban areas, was its high sediment load. Despite widespread hillslope erosion in the form of rilling and gullying initiated by overland flow, sediment from these sources typically did not reach valley bottoms, and only limited, small-scale mass wasting was observed. Field observations indicated that the sediment load was primarily derived from dramatic erosion of channel bed, bank, and floodplain material (i.e., valley fill). In the coastal city of Chañaral, flooding of the Salado River produced maximum water depths over 6 m, meters-thick mud deposition in buildings and along city streets, flow velocities larger than 8 m/s, and coastal erosion. Broader implications of studying the Atacama flooding include hazard reduction, the history of copper mining and more than five decades of contamination in many of the affected watersheds, and the Atacama's status as a terrestrial analog for Mars.

Mental health of indigenous school children in Northern Chile.

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Caqueo-Urízar, Alejandra; Urzúa, Alfonso; De Munter, Koen

2014-01-17

Anxiety and depressive disorders occur in all stages of life and are the most common childhood disorders. However, only recently has attention been paid to mental health problems in indigenous children and studies of anxiety and depressive disorders in these children are still scarce. This study compares the prevalence of anxiety and depressive symptoms in Aymara and non-Aymara children. Among the Aymara children, the study examines the relations between these symptoms and the degree of involvement with Aymara culture. We recruited 748 children aged 9 to 15 years from nine schools serving low socioeconomic classes in the city of Arica, in northern Chile. The children were equally divided between boys and girls and 37% of the children were Aymara. To evaluate anxiety and depressive symptoms we used the Stress in Children (SiC) instrument and the Children Depression Inventory-Short version (CDI-S), and used an instrument we developed to assess level of involvement in the Aymara culture. There was no significant difference between Aymara and non-Aymara children on any of the instrument scales. Dividing the Aymara children into high-involvement (n = 89) and low-involvement (n = 186) groups, the low-involvement group had significantly higher scores on the Hopelessness subscale of the CDI-S (p = 0.02) and scores of marginally higher significance in overall Anxiety on the SiC (p = 0.06). Although Aymara children have migrated from the high Andean plateau to the city, this migration has not resulted in a greater presence of anxiety and depressive symptoms. Greater involvement with the Aymara culture may be a protective factor against anxiety and depressive symptoms in Aymara children. This point to an additional benefit of maintaining cultural traditions within this population.

Evaluation of a New Mexico Landrace and Two Commercial Chile (Capsicum annuum Cultivars under Four Furrow Irrigation Schedules

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Israel Joukhadar

2018-02-01

Full Text Available Commercial and landrace chile (Capsicum annuum cultivars are cultivated under furrow irrigation systems in Northern New Mexico. Yield and physiological differences between commercial and landrace chile cultivars under furrow irrigation systems have not been evaluated. In 2011 and 2012 two commercial chiles, ‘Sandia’ and ‘NuMex Big Jim’, with one landrace chile, ‘Chimayo’, were evaluated under four irrigation schedules, with irrigation once every 7, 9, 11, and 13-days. These four schedules represent possible water availability for farmers in Northern New Mexico. In 2011 there were inconsistent yield patterns; fresh red chile yield of ‘Chimayo’ at the seven-day interval was 90% more than at the nine-day interval. ‘Sandia’ had 138% better yields at the seven- than at the nine-day interval. ‘Chimayo’ fresh green chile yields at the nine-day interval were 47% better than the seven-day interval. ‘NuMex Big Jim’ fresh green yields were 40% greater at the seven-day interval than the 13-day interval. In 2012 no yield components were statistically different for cultivars across irrigation intervals. This data shows commercial green and landrace chile cultivars can be furrow irrigated as water becomes available on 7, 9, 11, or 13-day intervals with no yield effect.

Late Pleistocene to Holocene tephrostratigraphy of the Lonquimay Volcano, South Central Chile

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Gilbert, D.; Freundt, A.; Kutterolf, S.; Burkert, C.

2010-12-01

The Lonquimay Volcanic Complex (LVC) in South Central Chile (38.38°S, 71.58°W) is part of the Southern Volcanic Zone of the Andes, which formed in response to the subduction of the Nazca Plate beneath the South American Plate. During the course of its magmatic evolution, the LVC produced explosive eruptions documented in the succession of widespread tephra deposits, as well as large lava flows that originated from the main edifice and several adjacent minor eruptive centers. The last eruptive phase in Lonquimays volcanic evolution occurred from 1988-1990. It led to the formation of the Navidad cinder cone with its associated 10.2 km long lava flow, and a widely distributed tephra blanket of andesitic composition (Moreno and Gardeweg, 1989). During recent field work we reinvestigated and complemented the LVC tephrostratigraphy as originally established by Polanco (1998)by detailed logging of 22 outcrops and collecting 126 stratigraphically controlled samples that were analyzed for their matrix glass, mineral and bulk rock compositions. This data set allows us to verify and extend the field-based correlations, and to establish a tephrostratigraphy for the LVC that comprises 15 stratigraphic units (LQA-LQO) and provides a framework for ongoing investigations of the petrogenetic evolution of the LVC. The stratigraphic record identifies at least 13 explosive eruptions of VEI > 3 that occurred since the last glaciation period (17150 a BP, McCulloch et al. 2000). Magmatic compositions of the tephra deposits range from basaltic scoriae (51wt% SiO2) to evolved dacitic pumice lapilli layers (67wt% SiO2), and thus have a wider compositional range than the chemically distinct andesitic lavas (57-63wt%) of the LVC. The vertical succession of tephra compositions reflects four periods of progressive magmatic differentiation, each successively tapped by several eruptions. The maximum degree of fractionation reached during these periods increases to younger ages. The

Zooplankton associated with the oxygen minimum zone system in the northern upwelling region of Chile during March 2000

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Escribano, Ruben; Hidalgo, Pamela; Krautz, Cristina

2009-07-01

Zooplankton in the coastal upwelling region off northern Chile may play a significant biogeochemical role by promoting carbon flux into the subsurface OMZ (oxygen minimum zone). This work identifies the dominant zooplankton species inhabiting the area influenced by the OMZ in March 2000 off Iquique (20°S, northern Chile). Abundance and vertical distribution studies revealed 17 copepod and 9 euphausiid species distributed between the surface and 600 m at four stations sampled both by day and by night. Some abundant species remained in the well-oxygenated upper layer (30 m), with no evidence of diel vertical migration, apparently restricted by a shallow (40-60 m) oxycline. Other species, however, were found closely associated with the OMZ. The large-sized copepod Eucalanus inermis was found below the oxycline and performed diel vertical migrations into the OMZ, whereas the very abundant Euphausia mucronata performed extensive diel vertical migrations between the surface waters and the core of the OMZ (200 m), even crossing it. A complete assessment of copepods and euphausiids revealed that the whole sampled water column (0-600 m) is occupied by distinct species having well-defined habitats, some of them within the OMZ. Ontogenetic migrations were evident in Eucalanidae and E. mucronata. Estimates of species biomass showed a substantial (>75% of total zooplankton biomass) daily exchange of C between the photic layer and the OMZ. Both E. inermis and E. mucronata can actively exchange about 37.8 g C m -2 d -1 between the upper well-oxygenated (0-60 m) layer and the deeper (60-600 m) OMZ layer. This migrant biomass may contribute about 7.2 g C m -2 d -1 to the OMZ system through respiration, mortality, and production of fecal pellets within the OMZ. This movement of zooplankton in and out of the OMZ, mainly as a result of the migratory behavior of E. mucronata, suggests a very efficient mechanism for introducing large amounts of freshly produced carbon into the OMZ

Tsunamigenic scenarios for southern Peru and northern Chile seismic gap: Deterministic and probabilistic hybrid approach for hazard assessment

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González-Carrasco, J. F.; Gonzalez, G.; Aránguiz, R.; Yanez, G. A.; Melgar, D.; Salazar, P.; Shrivastava, M. N.; Das, R.; Catalan, P. A.; Cienfuegos, R.

2017-12-01

Plausible worst-case tsunamigenic scenarios definition plays a relevant role in tsunami hazard assessment focused in emergency preparedness and evacuation planning for coastal communities. During the last decade, the occurrence of major and moderate tsunamigenic earthquakes along worldwide subduction zones has given clues about critical parameters involved in near-field tsunami inundation processes, i.e. slip spatial distribution, shelf resonance of edge waves and local geomorphology effects. To analyze the effects of these seismic and hydrodynamic variables over the epistemic uncertainty of coastal inundation, we implement a combined methodology using deterministic and probabilistic approaches to construct 420 tsunamigenic scenarios in a mature seismic gap of southern Peru and northern Chile, extended from 17ºS to 24ºS. The deterministic scenarios are calculated using a regional distribution of trench-parallel gravity anomaly (TPGA) and trench-parallel topography anomaly (TPTA), three-dimensional Slab 1.0 worldwide subduction zones geometry model and published interseismic coupling (ISC) distributions. As result, we find four higher slip deficit zones interpreted as major seismic asperities of the gap, used in a hierarchical tree scheme to generate ten tsunamigenic scenarios with seismic magnitudes fluctuates between Mw 8.4 to Mw 8.9. Additionally, we construct ten homogeneous slip scenarios as inundation baseline. For the probabilistic approach, we implement a Karhunen - Loève expansion to generate 400 stochastic tsunamigenic scenarios over the maximum extension of the gap, with the same magnitude range of the deterministic sources. All the scenarios are simulated through a non-hydrostatic tsunami model Neowave 2D, using a classical nesting scheme, for five coastal major cities in northern Chile (Arica, Iquique, Tocopilla, Mejillones and Antofagasta) obtaining high resolution data of inundation depth, runup, coastal currents and sea level elevation. The

Meteorological Conditions of Floods In The Chilean Andes Mountains

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Vergara, J.

Catastrophic floods occurred on mountains River during 2000 and 2001. The meteo- rological conditions of flood during the last five years have analyzed. For example, the flood of June 29 of 2000 occurred after one of extremely wettest June of the last 40 years were snowfall was 991cm in the Aconcagua Valley. Infrequently storms activ- ity generated a huge snowfall and rainfall over the Andes mountains on June of 2000 (1525mm in El Maule Valley) and the end of the unusually period, the flood was trig- gered by rising temperatures on the mountains and heavy rain (199mm in 24 hours) fall over the fresh snow on the morning of June 29 and floods wave developed and moved down along of the all river located on Central part of Chile, the foods peak was 2970.5m3/s on the El Maule basin in the morning of June 29. The regional meteoro- logical models with the hydrological forecasting was used for alert of the floods.

Terral De Vicuna, a Foehnlike Wind in Semiarid Northern Chile: Meteorological Aspects and Implications for the Fulfillment of Chill Requirements in Deciduous Fruit Trees

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Montes, Carlo; Rutllant, Jose A.; Aguirre, Anita; Bascunan-Godoy, Luisa; Julia, Cristobal

2016-01-01

The terral de Vicuña is a warm and dry wind that flows down the Elqui Valley in north-central Chile typically at dawn and early morning. Given that most terral episodes occur in austral winter when chill accumulation by deciduous fruit trees proceeds, negative effects on agriculture may be expected. During 11 (2004-14) winters a meteorological characterization of terral winds and the assessment of their impact on chill accumulation, by the modified Utah Model and the Dynamic Model, were performed. Within this period, 67 terral days (TD) were identified as those in which nighttime to early morning wind direction and speed, air temperature, and relative humidity reached defined thresholds on an hourly basis (terral hours). Most frequent TD featured 6-9 consecutive terral hours; duration is considered here as a proxy for their intensity. Synoptic-scale meteorological analysis shows that 65% of moderate and strong terral events develop as a cold, migratory anticyclone drifts poleward of the study area, coinciding with the onset of a midtropospheric ridge over central Chile, bringing southwest winds on top of the Andes (approximately 500-hPa level). The remaining 35% are either associated with 500-hPa easterlies (foehn like), with prefrontal conditions ahead of a trough driving northwest 500-hPa winds, or with transitional 500-hPa westerlies.Assessments of chill accumulation during TD show that, although present average and cold winter conditions do not represent a major TD hazard to local agriculture, lower chill accumulation associated with anomalously high nocturnal temperatures could be significantly more important during present and future warmer winters.

Methane fluxes from a wet puna ecosystem in the Peruvian Andes

Science.gov (United States)

Jones, Sam; Diem, Torsten; Priscila Huaraca Quispe, Lidia; Quispe Ccahuana, Adan Julian; Meir, Patrick; Arn Teh, Yit

2014-05-01

Discrepancies exist between top-down and bottom-up estimates of the tropical South American atmospheric methane budget. This suggests that current source-sink inventories fail to adequately characterise the landscapes of the region. This may be particularly true of Andean environments where very few field observations have been made. The high tropical Andes, between tree and permanent snow-lines, is home to diverse grass, shrub and giant rosette dominated ecosystems known variously from Venezuela to northern Chile and Argentina as paramo, jalca and puna. In humid regions these are characterised by wet, organic-rich mineral soils, peat-forming wetlands and shallow lakes. Such conditions are likely to promote methane production and potentially represent a regionally significant source to the atmosphere that should be considered. We report on methane fluxes from a bunch-grass dominated puna habitat at 3500 m above sea level in south-eastern Peru. Mean annual temperature and precipitation are 11 °C and 2500 mm, respectively. Temperature is aseasonal but experiences considerable diurnal variations with overnight frosting common-place. In contrast, rainfall is intensely episodic and has a pronounced wet season between September and March. Sampling encompassed a range of topographic features, such as grassland on freely draining, gently inclined or steep slopes and depressions containing bogs, over a 3 ha ridge to basin transition. Monthly sampling was carried out between January 2011 and June 2013 to investigate seasonal variability in methane fluxes. Intensive sampling campaigns were conducted to investigate spatial and short-term variations on a daily basis in two nine-day campaigns during wet and dry season. The site was a net source of methane to the atmosphere during the period of study. Methane fluxes were dominated by emissions from bogs, whereas, freely draining grassland exhibited weak source or marginal sink activity. Temporal variations were most notable at

Influence of spatial resolution on precipitation simulations for the central Andes Mountains

Science.gov (United States)

Trachte, Katja; Bendix, Jörg

2013-04-01

The climate of South America is highly influenced by the north-south oriented Andes Mountains. Their complex structure causes modifications of large-scale atmospheric circulations resulting in various mesoscale phenomena as well as a high variability in the local conditions. Due to their height and length the terrain generates distinctly climate conditions between the western and the eastern slopes. While in the tropical regions along the western flanks the conditions are cold and arid, the eastern slopes are dominated by warm-moist and rainy air coming from the Amazon basin. Below 35° S the situation reverses with rather semiarid conditions in the eastern part and temperate rainy climate along southern Chile. Generally, global circulation models (GCMs) describe the state of the global climate and its changes, but are disabled to capture regional or even local features due to their coarse resolution. This is particularly true in heterogeneous regions such as the Andes Mountains, where local driving features, e. g. local circulation systems, highly varies on small scales and thus, lead to a high variability of rainfall distributions. An appropriate technique to overcome this problem and to gain regional and local scale rainfall information is the dynamical downscaling of the global data using a regional climate model (RCM). The poster presents results of the evaluation of the performance of the Weather Research and Forecasting (WRF) model over South America with special focus on the central Andes Mountains of Ecuador. A sensitivity study regarding the cumulus parametrization, microphysics, boundary layer processes and the radiation budget is conducted. With 17 simulations consisting of 16 parametrization scheme combinations and 1 default run a suitable model set-up for climate research in this region is supposed to be evaluated. The simulations were conducted in a two-way nested mode i) to examine the best physics scheme combination for the target and ii) to

EL SECUESTRO DE LAS HISTORIAS INDÍGENAS: ITENERARIO Y LIMITACIONES DEL TIEMPO LINEAL EN CHILE

OpenAIRE

MAXIMILIANO SALINAS CAMPOS

2015-01-01

La historia de Chile está cruzada por el conflicto entre la cultura moderna europea y las culturas indígenas. El tiempo lineal impuesto por el Estado nacional ha dejado al descubierto su irresponsabilidad con el tiempo indígena de los Andes. Esta temporalidad expresa una profunda y sustentable «ontología arcaica». Tras el fin de la Guerra Fría, y la postdictadura de Pinochet, esta propuesta se vuelve acuciante con las demandas políticas y los desafíos epistémicos indígenas del siglo XXI. En...

EL SECUESTRO DE LAS HISTORIAS INDÍGENAS: ITINERARIO Y LIMITACIONES DEL TIEMPO LINEAL EN CHILE

OpenAIRE

Salinas Campos, Maximiliano

2015-01-01

La historia de Chile está cruzada por el conflicto entre la cultura moderna europea y las culturas indígenas. El tiempo lineal impuesto por el Estado nacional ha dejado al descubierto su irresponsabilidad con el tiempo indígena de los Andes. Esta temporalidad expresa una profunda y sustentable «ontología arcaica». Tras el fin de la Guerra Fría, y la postdictadura de Pinochet, esta propuesta se vuelve acuciante con las demandas políticas y los desafíos epistémicos indígenas del siglo XXI. En e...

The text of the Agreement of 22 September 1982 between Chile and the Agency for the application of safeguards in connection with the supply of nuclear material from the United Kingdom of Great Britain and Northern Ireland

International Nuclear Information System (INIS)

1983-07-01

The full text of the agreement of 22 September 1982 between Chile and the Agency for the application of safeguards to nuclear material supplied from the United Kingdom of Great Britain and Northern Ireland is presented

Presencia de los géneros invasores Mus y Rattus en áreas naturales de Chile: un riesgo ambiental y epidemiológico Presence of the invasive genera Mus and Rattus in natural areas in Chile: an environmental and epidemiological risk

Directory of Open Access Journals (Sweden)

GABRIEL LOBOS

2005-03-01

Full Text Available Realizamos un estudio que incluyó muestreos y prospecciones en un gradiente latitudinal en Chile continental para determinar la presencia y ausencia de roedores murinos introducidos, particularmente Mus musculus, Rattus rattus y R. norvegicus en áreas naturales o silvestres a lo largo de Chile. Además se analizó el riesgo epidemiológico que representan estas especies en el marco de un estudio sobre el virus Hanta. Los resultados mostraron que M. musculus rara vez es recolectado en áreas naturales. Sin embargo, las dos especies de Rattus han invadido ampliamente la región mediterránea chilena. Las regiones desérticas, los ambientes de alturas y las regiones australes, serían biótopos restringidos para estos invasores. Desde una perspectiva epidemiológica, la presencia del virus Hanta (variedades Andes y Seoul en Rattus es un elemento que demuestra que las especies invasoras además de generar impactos ecológicos, pueden ocasionar problemas económicos y de salud pública. La fragilidad de los ecosistemas mediterráneos determina que la presencia de especies exóticas constituya un elemento de alto riesgo para la conservación del patrimonio natural del país. Probablemente, la conservación de áreas naturales constituye la mejor herramienta para enfrentar a estas especies exóticasWe conducted a latitudinal study in natural areas of continental Chile to evaluate the occurrence of the introduced murine rodents Mus musculus, Rattus rattus and R. norvegicus. Furthermore, we evaluated the epidemiological risk of these species as part of an ongoing study on Hantavirus. The results allowed us to conclude that M. musculus occurs rarely in natural environments. However, the two species of Rattus have widely invaded the mediterranean region of Chile. Desert, altitudinal and high latitude regions seem to be restricted areas for these invasive rodents. From an epidemiological perspective, the occurrence of Hantavirus in Rattus (Andes and Seoul

Seasonal and geographical variability in some trace elements of Pacific oysters (Crassostrea Gigas) cultured in two different bays of Northern Chile

International Nuclear Information System (INIS)

Gras, N.; Thieck, M.; Munoz, L.

1991-01-01

Chile has approximately 4,500 kilometers of continental coastline on the Pacific Ocean. It is therefore in a favorable position to develop fishing activities, since its waters contain a great variety of marine resources, namely, fish, shellfish and seaweeds. Fishing in Chile plays an important role in production. Metal contamination of the marine ecosystem is a pervasive and worldwide problem. Consequently, seafood consuming and exporting countries have gradually increased the need to improve the quality of their products in order to meet the required standards. In turn, this implies the need to adopt more efficient methods to analyze these resources by carrying out studies that will provide greater integral knowledge on the levels of essential and toxic trace elements found in seafood. In the present study, seasonal and geographical variability of some trace elements content of Pacific Oysters (Crassostrea Gigas) cultured, greatly demanded on the international market, are investigated. Samples for the analysis were collected from two different bays of Northern Chile, where heavy-metal pollution is already recognized as a problem. The trace elements content of this mollusk was studied at monthly intervals for 12 months (September 1987-August 1988). The determination of Cu was carried out using radiochemical neutron activation analysis and the other trace elements like Cd, As, Br, Na, Se, Cr, Fe, Zn and Co, were determined through neutron activation analysis in its purely instrumental form. NBS Standard Reference Materials were used to determine the accuracy of both methods. Significant differences were found comparing the content of copper and cadmium at the different seasons and locations of capture

Changing Student Attitudes using Andes, An Intelligent Homework System

Science.gov (United States)

van de Sande, Brett; Vanlehn, Kurt; Treacy, Don; Shelby, Bob; Wintersgill, Mary

2007-03-01

The size of introductory physics lectures often inhibits personal homework assistance and timely corrective feedback. Andes, an intelligent homework help system designed for two semesters of introductory physics, can fill this need by encouraging students to use sound problem solving techniques and providing immediate feedback on each step of a solution. On request, Andes provides principles-based hints based on previous student actions. A multi-year study at the U.S. Naval Academy demonstrates that students using Andes perform better than students working the same problems as graded pencil and paper homeworks. In addition, student attitude surveys show that Andes is preferred over other homework systems. These findings have implications for student attitudes toward, and mastery of, physics. See http://www.andes.pitt.edu for more information.

Coupling between the environment and the pelagic resources exploited off northern Chile: ecosystem indicators and a conceptual model Acoplamiento entre el ambiente y los recursos pelágicos explotados en el norte de Chile: un modelo conceptual

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Eleuterio Yáñez

2008-01-01

Full Text Available The eastern boundary of the Chile-Peru Current System constitutes one of the most biologically productive ecosystems in the world, due largely to coastal upwelling and the horizontal advection of nutrients. In this ecosystem, El Niño events are of great importance in the interannual variability of the environment. A change was observed in the environmental regime at the beginning of the 1970s with the onset of the 1972-1973 El Niño, marking an important decrease in the anchovy fishery (Engraulis ringens. After the mid-1970s, sardine (Sardinops sagax landings increased noticeably. A second regime shift at the end of the 1980s was seen mostly in the noticeable recovery of anchovy and the decline of sardine. Herein, we present an integrated conceptual model of the different local and large-scale phenomena that affect the marine environment off northern Chile and the distribution and abundance of pelagic resources. The model considers an analysis of environmental and bio-fishery data on different scales and describes how the interdecadal (associated with re-gime shifts and interannual (associated with El Niño events fluctuations in the Equatorial Pacific are mani-fested in the eastern South Pacific and, therefore, in the northern zone off Chile, affecting the annual eyele, the dynamic of the coastal trapped waves, and coastal upwelling. In this framework, interdecadal fluctuations play an important role in the anchovy-sardine-anchovy replacement sequence.El borde oriental del Sistema de Corrientes de Chile-Perú constituye uno de los ecosistemas de mayor productividad biológica del mundo, debido principalmente a la surgencia costera y advección horizontal de nutrientes. En este ecosistema, los eventos El Niño son de mayor importancia en la variabilidad interanual del ambiente. No obstante, un cambio de régimen ambiental es observado a inicio de los 70's el que hubiera comenzado con El Niño 1972-73 y que marca la gran disminución de la

The Ongoing 2011 Eruption of Cordón Caulle (Southern Andes) and its Related Hazards

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Amigo, A.; Lara, L. E.; Silva, C.; Orozco, G.; Bertin, D.

2011-12-01

On June 4, 2011, at 18:45 UTC, Cordón Caulle volcano (Southern Andes, 40.52S, 72.14W) erupted explosively after 51 years of quiescence. The last eruption occurred in 1960 and was triggered by the great Mw 9.5 Chile earthquake. The ongoing eruption started after 2 months of increased shallow seismicity as recorded by OVDAS (the volcano observatory at Sernageomin). This close monitoring effort allowed a timely eruption forecast with at least 3 hours of warning, which facilitated the crisis response. In addition to this successful performance, for the first time in Chile volcanic hazards were assessed in advance supporting the emergency management. In particular, tephra dispersal was daily forecasted using the ASHFALL advection-diffusion model and potential lahars and PDC impact zones were delineated according to numerical approaches. The first eruptive stage lasted 27 hours. It was characterized by ca. 15-km strong Plinian-like column, associated with the emission of 0.2 - 0.4 km3 of magma (DRE). Tephra fallout mostly occurred in Chile and Argentina, although fine particles and aerosols circumnavigated the globe twice, causing disruptions on air navigation across the Southern Hemisphere. The second ongoing eruptive stage has been characterized by persistent weak plumes and lava emission at effusion rates in the range of 20 and 60 m3/s, which total volume is estimated case of successful eruption forecast and hazards assessment but it is also an important case-study of silicic eruptions in an arc segment where mostly mafic magmas have been erupted during the Holocene.

Different Phases of Earthquake Cycle Reflected in GPS Measured Crustal Deformations along the Andes

Science.gov (United States)

Khazaradze, G.; Klotz, J.

2001-12-01

The South American Geodynamic Activities (SAGA) project was initiated in 1993 by the GeoForschungsZentrum together with host organizations in Argentina and Chile with the main objective of studying the kinematics and dynamics of present-day deformation processes along the central and southern Andes. Currently the SAGA network consists of 230 geodetic markers spanning more than 2000 km long distance from Peru/Chile border in the north to Cape Horn in the south. The majority of the observed crustal deformation field is relatively homogenous: roughly parallel to the plate convergence direction and decreasing in magnitude away from the deformation front. This pattern is characteristic for the \\textit{inter-seismic} phase of earthquake deformation cycle and can be explained by the elastic strain accumulation due to locking of the thrust interface between the subducting Nazca and the overriding South America plates. However, in addition to the dominant inter-seismic signal, close examination of the observed velocity field also reveals significant spatial and temporal variations, contrary to the commonly used assumption of constant deformation rates. This variation is especially pronounced for the measurements in the vicinity of the 1995 Mw8.0 Antofagasta earthquake (22{° }S-26{° }S). Here, after capturing up to 1 meters of \\textit{co-seismic} displacements associated with this event, the analysis of data obtained during the three following field campaigns (1996-1999), reveals highly time dependent deformation pattern. This can be explained by the decreasing importance of \\textit{post-seismic} effects of the Antofagasta event relative to the increasing dominance of the inter-seismic phase of subduction. Perhaps, even more interesting time dependent observations have been detected in the southern part the SAGA network (38{° }S-43{° }S).Here, after 35 years of the occurrence of the 1960 Mw9.5 Chile earthquake, we still see the continuing post-seismic effects of this

A glacial record of the last termination in the southern tropical Andes

Science.gov (United States)

Bromley, G. R.; Schaefer, J. M.; Winckler, G.; Hall, B. L.; Todd, C. E.; Rademaker, K.

2012-12-01

The last glacial termination represents the highest-magnitude climate change of the last hundred thousand years. Accurate resolution of events during the termination is vital to our understanding of how - and why - the global climate system transitions from a full glacial to interglacial state, as well as the causes of abrupt climate change during the late-glacial period. Palaeoclimate data from low latitudes, though relatively sparse, are particularly valuable, since the tropical ocean and atmosphere likely play a crucial role in Quaternary climate variability on all timescales. We present a detailed glacier record from the Andes of southern Peru (15°S), resolved with 3He surface-exposure dating and spanning the last glacial maximum and termination. Our dataset reveals that glaciers in this part of the Southern Hemisphere maintained their Late Pleistocene maxima for several millennia and that the onset of the termination may have occurred relatively late. Deglaciation was punctuated by two major advances during the late-glacial period. Following the glacial-interglacial transition, our preliminary chronologic and morphologic data suggest that, in contrast to the Northern Hemisphere, glaciers in the southern tropical Andes have experienced overall shrinkage during the Holocene.

Kinematics, Exhumation, and Sedimentation of the North Central Andes (Bolivia): An Integrated Thermochronometer and Thermokinematic Modeling Approach

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Rak, Adam J.; McQuarrie, Nadine; Ehlers, Todd A.

2017-11-01

Quantifying mountain building processes in convergent orogens requires determination of the timing and rate of deformation in the overriding plate. In the central Andes, large discrepancies in both timing and rate of deformation prevent evaluating the shortening history in light of internal or external forcing factors. Geologic map patterns, age and location of reset thermochronometer systems, and synorogenic sediment distribution are all a function of the geometry, kinematics, and rate of deformation in a fold-thrust-belt-foreland basin (FTB-FB) system. To determine the timing and rate of deformation in the northern Bolivian Andes, we link thermokinematic modeling to a sequentially forward modeled, balanced cross section isostatically accounting for thrust loads and erosion. Displacement vectors, in 10 km increments, are assigned variable ages to create velocity fields in a thermokinematic model for predicting thermochronometer ages. We match both the pattern of predicted cooling ages with the across strike pattern of measured zircon fission track, apatite fission track, and apatite (U-Th)/He cooling ages as well as the modeled age of FB formations to published sedimentary sections. Results indicate that northern Bolivian FTB deformation started at 50 Ma and may have begun as early as 55 Ma. Acceptable rates of shortening permit either a constant rate of shortening ( 4-5 mm/yr) or varying shortening rates with faster rates (7-10 mm/yr) at 45-50 Ma and 12-8 Ma, significantly slower rates (2-4 mm/yr) from 35 to 15 Ma and indicate the northern Bolivian Subandes started deforming between 19 and 14 Ma.

Seismicity Structure of the Downgoing Nazca Slab in Northern Chile

Science.gov (United States)

Sippl, C.; Schurr, B.

2017-12-01

We applied an automatized earthquake detection and location algorithm to 8 years of continuous seismic data from the IPOC network in Northern Chile, located in the forearc between about 18.5°S and 24°S. The resulting seismicity catalog contains more than 113k double-difference relocated earthquake hypocenters and features a completeness magnitude around 2.8. Despite the occurrence of two megathrust earthquakes with vigorous aftershock seismicity in the studied time period (the 2007 Tocopilla and the 2014 Iquique earthquakes), >60% of the retrieved seismicity is located in a highly active band of intermediate-depth earthquakes (80-120 km deep) within the downgoing Nazca slab.We obtain a triple seismic zone in the updip part of the slab, with the three parallel dipping planes corresponding to the plate interface, the oceanic Moho (ca. 8 km below the interface) and a third band in the mantle lithosphere 26-28 km beneath the slab top. The plate interface seismicity terminates abruptly at a depth of 55 km. At about 80-90 km depth, the remaining two planes of seismicity then merge into the single, 20 km thick cluster of vigorous seismicity mentioned above, which terminates at 120 km depth. This cluster is located directly beneath the volcanic arc and shows a pronounced kink in the slab dipping angle. Intra-slab seismicity is most likely related to metamorphic dehydration reactions, hence our high-resolution earthquake distribution can be considered a map of metamorphic reactions (although a possibly incomplete one, since not all reactions necessarily invoke seismicity). By correlating this distribution with isotherms from thermal models as well as geophysical imaging results from previous studies, we attempt to get a glimpse at the processes that produce the different patches of intraslab seismicity at intermediate depths.

High-resolution paleoclimate records of Holocene hydroclimatic variability in the Eastern Colombian Andes from Lago de Tota

Science.gov (United States)

Ahmed, M. N.; Bird, B. W.; Escobar, J.; Polissar, P. J.

2017-12-01

The Northern Hemisphere (NH) South American Monsoon (SAM) is a significant source of precipitation for the North Andes (north of 0˚) and has major control over regional hydroclimate variability. Holocene-length histories of NH SAM variability are few compared to the Southern Hemisphere (SH), limiting understanding of how these systems are connected on orbital and shorter timescales. Here, we present multi-proxy lake-sediment-based paleoclimate and paleohydrologic reconstructions from Lago de Tota, Colombia, using sedimentological, geochemical and leaf-wax hydrogen isotopic indicators from radiometically dated cores. The results indicate periods of wet and dry climate phases during the past 9000 BP with an average Holocene sedimentation rate 33cm/kyr. An increase in total organic matter (TOM) content and finer grain-size distributions was observed from 8000 to 3200 BP, suggesting a period of high lake level. This was followed by lower TOM and coarser grain sizes, suggesting lower lake levels from 3200 BP to the present. Although Tota's lake level pattern is antiphased with other lake level reconstructions from the NH and SH Andes, it is consistent with hypothesized changes in atmospheric convection over the Andes during the Holocene and the way in which they would be modified by the so-called dry island effect in the Colombian Andes. This suggests that a common forcing mechanism can be invoked to explain differing millennial-scale Andean hydroclimate changes, namely atmospheric convection. Orbital and Pacific atmosphere-forcing are therefore likely to have played a significant role in driving pan-Andean hydroclimate variability based on their inter-hemispheric influence on Andean convection.

Terrigenous sediment supply along the Chilean continental margin: modern regional patterns of texture and composition

Science.gov (United States)

Lamy, F.; Hebbeln, D.; Wefer, G.

The regional patterns of texture and composition of modern continental slope and pelagic sediments off Chile between 25°S and 43°S reflect the latitudinal segmentation of geological, morphological, and climatic features of the continental hinterland. Grain-size characteristics are controlled by the grain-size of source rocks, the weathering regime, and mode of sediment input (eolian off northern Chile vs fluvial further south). Bulk-mineral assemblages reveal a low grade of maturity. Regional variations are governed by the source-rock composition of the different geological terranes and the relative source-rock contribution of the Coastal Range and Andes, as controlled by the continental hydrology. The relative abundance of clay minerals is also predominantly influenced by the source-rock composition and partly by continental smectite neoformation. Latitudinal variations of illite crystallinities along the Chilean continental slope (and west of the Peru-Chile trench) clearly reflect modifications of the weathering regime which correspond to the strong climatic zonation of Chile.

Draft genome sequence of chloride-tolerant Leptospirillum ferriphilum Sp-Cl from industrial bioleaching operations in northern Chile.

Science.gov (United States)

Issotta, Francisco; Galleguillos, Pedro A; Moya-Beltrán, Ana; Davis-Belmar, Carol S; Rautenbach, George; Covarrubias, Paulo C; Acosta, Mauricio; Ossandon, Francisco J; Contador, Yasna; Holmes, David S; Marín-Eliantonio, Sabrina; Quatrini, Raquel; Demergasso, Cecilia

2016-01-01

Leptospirillum ferriphilum Sp-Cl is a Gram negative, thermotolerant, curved, rod-shaped bacterium, isolated from an industrial bioleaching operation in northern Chile, where chalcocite is the major copper mineral and copper hydroxychloride atacamite is present in variable proportions in the ore. This strain has unique features as compared to the other members of the species, namely resistance to elevated concentrations of chloride, sulfate and metals. Basic microbiological features and genomic properties of this biotechnologically relevant strain are described in this work. The 2,475,669 bp draft genome is arranged into 74 scaffolds of 74 contigs. A total of 48 RNA genes and 2,834 protein coding genes were predicted from its annotation; 55 % of these were assigned a putative function. Release of the genome sequence of this strain will provide further understanding of the mechanisms used by acidophilic bacteria to endure high osmotic stress and high chloride levels and of the role of chloride-tolerant iron-oxidizers in industrial bioleaching operations.

[First report of Montagnea arenaria (D.C.) Zeller (Agaricales) in Chile].

Science.gov (United States)

Madrid Lorca, Hugo; Muñoz, Mélica

2006-06-01

Montagnea arenaria (D.C.) Zeller (Agaricales), an interesting basidiomycete adapted to arid environments is recorded for the first time from a sample collected on sandy soil in the northern zone of Chile. Its mature fruiting body is described. Taxonomic and ecological comments are also addressed.

Light hydrocarbons as redox and temperature indicators in the geothermal field of El Tatio (northern Chile)

Energy Technology Data Exchange (ETDEWEB)

Tassi, F. [University of Florence (Italy). Dept. of Earth Sciences; Martinez, C. [University Catolica del Norte, Antofagasta (Chile). Dept. of Earth Science; Vaselli, O. [University of Florence (Italy). Dept. of Earth Sciences; Institute of Geosciences and Earth Resources, Florence (Italy). National Council of Research; Capaccioni, B. [University of Urbino (Italy). Institute of Volcanology and Geochemistry; Viramonte, J. [National University of Salta (Argentina). Institute GEONORTE and CONICET

2005-11-15

El Tatio (northern Chile), one of the largest geothermal fields of South America, is presently undergoing a new program of geothermal exploration, after the failure of the first exploration phase in the early 1970s. The geochemical features of the fluid discharges characterizing this system mainly consist of boiling pools and fumaroles, and represent the result of a complex mixing process involving 3 main components: (i) hydrothermal; (ii) atmospheric; (iii) magmatic. Chemical reactions involving light hydrocarbons equilibrate at higher temperature than those directly measured in the geothermal wells and calculated on the basis of the composition of the inorganic gas species. This suggests that in the deeper parts of the hydrothermal system temperatures higher than 300{sup o}C may be achieved. Such results can have a strong impact for the evaluation of the potential resources of this geothermal system. Moreover, the chemical characteristics of the organic gas fraction allow the assessment of the chemical-physical conditions governing the geochemical processes acting on geothermal fluids at depth. (author)

Insights on the structural control of a Neogene forearc basin in Northern Chile: A geophysical approach

Science.gov (United States)

García-Pérez, Tiaren; Marquardt, Carlos; Yáñez, Gonzalo; Cembrano, José; Gomila, Rodrigo; Santibañez, Isabel; Maringue, José

2018-06-01

The comprehensive study of intramountain basins located in the Coastal Cordillera of the continental emergent Andean forearc in Northern Chile, enables the better understanding of the nature and evolution of the upper crustal deformation during the Neogene and Quaternary. A case study is the extensive extensional half-graben Alto Hospicio basin. The basin is cut by the Coastal Cliff, which exposes the deformed Neogene basin fill. Also exposed are several structural systems, some of which affect Quaternary surfaces. The results of the integrated geophysical surveys (Electromagnetic Transient and Gravity) allow us to fully constrain the geometry of the Alto Hospicio basin and the lithological relationship between the subsurface geological units. The structural geology analysis assesses the deformation regimes affecting the faults present in the basin and surrounding area. Altogether evidence a change in the deformation regime from an EW extensional deformation during the Miocene-Pliocene to a NS compression in the Quaternary as is presented in this study. We suggest this deformation change is related to a small change in the convergence vector orientation during the Pliocene.

Wearing the marks of violence: Unusual trauma patterning at Coyo Oriental, Northern Chile.

Science.gov (United States)

Torres-Rouff, Christina; Hubbe, Mark; Pestle, William J

2018-05-02

In this article, we present analyses of traumatic injury data from the Middle Period Coyo Oriental cemetery in northern Chile. We test a series of hypotheses about the role of sex, foreign contact, ritual access, and temporal shifts, in the patterning of cranial trauma in this cemetery. Two hundred and twenty-seven crania from Coyo Oriental were analyzed using standard bioarcheological methods to determine sex and age as well as the presence of cranial fractures. We also documented the presence of Tiwanaku goods, objects tied to warfare or hunting, camelid offerings, snuff paraphernalia, and items related to mining. We recorded 98 cranial fractures in the sample with 94.9% (93/98) on the anterior of the cranium. No significant differences are observed in the prevalence of trauma by sex, type of grave, or date. However, Coyo Oriental's trauma prevalence is two to three times higher than other Middle Period sites. The prevalence and location of these injuries suggest that conflict at Coyo Oriental, while of the same nature, was at a scale different to that seen elsewhere in the oases. We posit here that the development of social hierarchy, population growth, expansive social networks, and foreign contact that characterized the Middle Period may have resulted in a need for social control among the emergent elites of the region. © 2018 Wiley Periodicals, Inc.

National control and eradication program of bovine tuberculosis in Chile.

Science.gov (United States)

Max, Vanessa; Paredes, Luis; Rivera, Alejandro; Ternicier, Claudio

2011-07-05

There have been reports of the presence of bovine tuberculosis (TB) in Chile for more than 100 years. Several prevalence studies have revealed that there is a wide spectrum of disease across the country with certain geographic areas where the disease is endemic through to other geographic areas where infection is sporadic and at very low prevalence. In 2009, this information was used to divide Chile into different geographic zones based on prevalence rates. This will enable the correct actions to be undertaken to reduce the prevalence of TB. Thus the northern part of Chile which has a medium to high prevalence of TB will be categorized as a control zone. In contrast, the southern part of Chile which has a high proportion of the bovine population, has a low prevalence of TB and will be classified as an eradication zone (Paredes, 2008). Although there have been several past attempts to create a national control and eradication program in Chile, none has been successful. A national program is proposed, and outlined in this paper. Progress toward program initiation in 2009 has been difficult, mostly because of the global economic crisis, difficulties in the milk and meat industry, and social and political issues. Copyright © 2011 Elsevier B.V. All rights reserved.

Scale of human mobility in the southern Andes (Argentina and Chile): A new framework based on strontium isotopes.

Science.gov (United States)

Barberena, Ramiro; Durán, Víctor A; Novellino, Paula; Winocur, Diego; Benítez, Anahí; Tessone, Augusto; Quiroga, María N; Marsh, Erik J; Gasco, Alejandra; Cortegoso, Valeria; Lucero, Gustavo; Llano, Carina; Knudson, Kelly J

2017-10-01

The goal of this article is to assess the scale of human paleomobility and ecological complementarity between the lowlands and highlands in the southern Andes during the last 2,300 years. By providing isotope results for human bone and teeth samples, we assess a hypothesis of "high residential mobility" suggested on the basis of oxygen isotopes from human remains. We develop an isotopic assessment of human mobility in a mountain landscape combining strontium and oxygen isotopes. We analyze bone and teeth samples as an approach to life-history changes in spatial residence. Human samples from the main geological units and periods within the last two millennia are selected. We present a framework for the analysis of bioavailable strontium based on the combination of the geological data with isotope results for rodent samples. The 87 Sr/ 86 Sr values from human samples indicate residential stability within geological regions along life history. When comparing strontium and oxygen values for the same human samples, we record a divergent pattern: while δ 18 O values for samples from distant regions overlap widely, there are important differences in 87 Sr/ 86 Sr values. Despite the large socio-economic changes recorded, 87 Sr/ 86 Sr values indicate a persisting scenario of low systematic mobility between the different geological regions. Our results suggest that strontium isotope values provide the most germane means to track patterns of human occupation of distinct regions in complex geological landscapes, offering a much higher spatial resolution than oxygen isotopes in the southern Andes. © 2017 Wiley Periodicals, Inc.

Cenozoic basin thermal history reconstruction and petroleum systems in the eastern Colombian Andes

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Parra, Mauricio; Mora, Andres; Ketcham, Richard A.; Stockli, Daniel F.; Almendral, Ariel

2017-04-01

Late Mesozoic-Cenozoic retro-arc foreland basins along the eastern margin of the Andes in South America host the world's best detrital record for the study of subduction orogenesis. There, the world's most prolific petroleum system occur in the northernmost of these foreland basin systems, in Ecuador, Colombia and Venezuela, yet over 90% of the discovered hydrocarbons there occur in one single province in norteastern Venezuela. A successful industry-academy collaboration applied a multidisciplinary approach to the study of the north Andes with the aim of investigating both, the driving mechanisms of orogenesis, and its impact on hydrocarbon accumulation in eastern Colombia. The Eastern Cordillera is an inversion orogen located at the leading edge of the northern Andes. Syn-rift subsidence favored the accumulation of km-thick organic matter rich shales in a back-arc basin in the early Cretaceous. Subsequent late Cretaceous thermal subsidence prompted the accumulation of shallow marine sandstones and shales, the latter including the Turonian-Cenomanian main hydrocarbon source-rock. Early Andean uplift since the Paleocene led to development of a flexural basin, filled with mainly non-marine strata. We have studied the Meso-Cenozoic thermal evolution of these basins through modeling of a large thermochronometric database including hundreds of apatite and zircon fission-track and (U-Th)/He data, as well as paleothermometric information based on vitrinite reflectance and present-day temperatures measured in boreholes. The detrital record of Andean construction was also investigated through detrital zircon U-Pb geochronometry in outcrop and borehole samples. A comprehensive burial/exhumation history has been accomplished through three main modeling strategies. First, one-dimensional subsidence was used to invert the pre-extensional lithospheric thicknesses, the magnitude of stretching, and the resulting heat flow associated to extension. The amount of eroded section and

The Neogene rise of the tropical Andes facilitated diversification of wax palms (Ceroxylon: Arecaceae) through geographical colonization and climatic niche separation

DEFF Research Database (Denmark)

Sanín, María José; Kissling, W. Daniel; Bacon, Christine D.

2016-01-01

The tropical Andes are a biodiversity hotspot, partly due to their rich and complex floristic composition. A fundamental question regarding this outstanding biodiversity is what role the Andean orogeny has played in species diversification. Ceroxylon is a genus of endemic Andean palms that stands...... gradients. Ancestral areas were reconstructed under a model allowing for founder-event speciation and climatic niches were inferred from climatic variables at present-day occurrences of all species. Niche evolution in a phylogenetic framework was evaluated by testing differences between the climatic niches...... of clades. Our analyses identified four main clades, with a general pattern of diversification through geographical colonization from south to north after the Pliocene uplift of the northern Andes. Adaptation to low temperatures was conserved at the generic level, with climatic niche differentiation among...

Observations of Comets and Eclipses in the Andes

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Ziółkowski, Mariusz

There is no doubt that the Incas possessed a system for observing and interpreting unusual astronomical phenomena, such as eclipses or comets. References to it, however, are scarce, often of anecdotal nature and are not collected into any coherent "Inca observation catalog". The best documented of such events is the "Ataw Wallpa's comet", seen in Cajamarca in July of 1533 and the solar eclipse, that in 1543, prevented conquistador Lucas Martínez from discovering the rich silver mines in northern Chile. Archived descriptions of the Andean population's reaction to these phenomena indicate that they were treated as extremely important omens, that should not, under any circumstances, be ignored.

Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador.

Science.gov (United States)

Zapata-Ríos, Galo; Branch, Lyn C

2018-01-01

Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km) were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus), puma (Puma concolor), striped hog-nosed skunk (Conepatus semistriatus), and Andean bear (Tremarctos ornatus)]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

Biomass size-spectra of macrobenthic communities in the oxygen minimum zone off Chile

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Quiroga, Eduardo; Quiñones, Renato; Palma, Maritza; Sellanes, Javier; Gallardo, Víctor A.; Gerdes, Dieter; Rowe, Gilbert

2005-01-01

Estimates of macrofaunal secondary production and normalized biomass size-spectra (NBSS) were constructed for macrobenthic communities associated with the oxygen minimum zone (OMZ) in four areas of the continental margin off Chile. The presence of low oxygen conditions in the Humboldt Current System (HCS) off Chile was shown to have important effects on the size structure and secondary production of the benthic communities living in this ecosystem. The distribution of normalized biomass by size was linear (log 2-log 2 scale) at all stations. The slope of the NBSS ranged from -0.481 to -0.908. There were significant differences between the slopes of the NBS-spectra from the stations located in the OMZ (slope = -0.837) and those located outside the OMZ (slope = -0.463) ( p oxygen conditions (Chile (6.8 g C m -2 y -1) than off northern Chile (2.02 g C m -2 y -1) and off southern Chile (0.83 g C m -2 y -1). A comparison with other studies suggests that secondary production in terms of carbon equivalents was higher than in other upwelling regions.

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.

Lymnaea viatrix and Lymnaea columella in the neotropical region: a distributional outline

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W. Lobato Paraense

1982-06-01

Full Text Available A review of lymnaeid samples collected by the author from 106 localities in Mexico, Cuba, Jamaica, Haiti, Dominican Republic, Puerto Rico, Martinique, Saint Lucia, Guatemala, Costa Rica, Panamá, Ecuador, Peru, Bolivia, Chile, Argentina, Uruguay andBrazil showed that one of them (from Ecuador belonged to Lymnaea cousini Jousseaume, 1887, and all the others to either L. viatrix Orbigny, 1835 or l. columella Say, 1817. The ranges of L. viatrix and L. columella overlap in Middle America, and in northern and southern South America (Venezuela-Colombia-Ecuador and northeastern Argentina-Uruguay-southernmost Brazil, respectively. L. viatrix was the only species found in Peru west of the Andes and in Chile, and is supposed to have migrated eastward to Argentina via the Negro river basin. The range of L. columella in South America is discontinuous. The species has been recorded from Venezuela, Colombia and Ecuador and, east of the Andes, from latitudes 15º S (central-west Brazil to 35º S (La Plata, Argentina. Such a gap may be attributed to either introduction from the northern into the southern area, or migration along the unsampled region on the eastern side of the Andes, or extinction in the now vacant area. No lymnaeids have been found so far in Brazil north of latitude 15º S and in the Guianas.A revisão de amostras de limneídeos coletados pelo autor em 106 localidades no México, Cuba, Jamaica, Haiti, República Dominicana, Porto Rico, Martinica, Santa Lúcia, Guatemala, Costa Rica, Panamá, Equador, Peru, Bolívia, Chile, Argentina, Uruguai e Brasil mostrou que uma delas (do Equador pertencia a Lymnaea cousini Jousseaume, 1887, e que todas as outras pertenciam a L. viatrix Orbigny, 1835 ou a L. columella Say, 1817. As distribuições da L. viatrix e da l. columella sobrepõem-se na Meso-América e na América do Sul setentrional (Venezuela-Colômbia-Equador e meridional (nordeste da Argentina-Uruguai-extremo sul do Brasil. A L. viatrix foi a

Imaging Seismic Source Variations Using Back-Projection Methods at El Tatio Geyser Field, Northern Chile

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Kelly, C. L.; Lawrence, J. F.

2014-12-01

During October 2012, 51 geophones and 6 broadband seismometers were deployed in an ~50x50m region surrounding a periodically erupting columnar geyser in the El Tatio Geyser Field, Chile. The dense array served as the seismic framework for a collaborative project to study the mechanics of complex hydrothermal systems. Contemporaneously, complementary geophysical measurements (including down-hole temperature and pressure, discharge rates, thermal imaging, water chemistry, and video) were also collected. Located on the western flanks of the Andes Mountains at an elevation of 4200m, El Tatio is the third largest geyser field in the world. Its non-pristine condition makes it an ideal location to perform minutely invasive geophysical studies. The El Jefe Geyser was chosen for its easily accessible conduit and extremely periodic eruption cycle (~120s). During approximately 2 weeks of continuous recording, we recorded ~2500 nighttime eruptions which lack cultural noise from tourism. With ample data, we aim to study how the source varies spatially and temporally during each phase of the geyser's eruption cycle. We are developing a new back-projection processing technique to improve source imaging for diffuse signals. Our method was previously applied to the Sierra Negra Volcano system, which also exhibits repeating harmonic and diffuse seismic sources. We back-project correlated seismic signals from the receivers back to their sources, assuming linear source to receiver paths and a known velocity model (obtained from ambient noise tomography). We apply polarization filters to isolate individual and concurrent geyser energy associated with P and S phases. We generate 4D, time-lapsed images of the geyser source field that illustrate how the source distribution changes through the eruption cycle. We compare images for pre-eruption, co-eruption, post-eruption and quiescent periods. We use our images to assess eruption mechanics in the system (i.e. top-down vs. bottom-up) and

LA-ICP-MS zircon U-Pb geochronology to constrain the age of post-Neocomian continental deposits of the Cerrillos Formation, Atacama Region , northern Chile: tectonic and metallogenic implications Geocronología U-Pb en circón por LA-ICP-MS para circunscribir la edad de depósitos continentales post-neocomianos de la Formacion Cerrillos, Región de Atacama, norte de Chile: implicancias tectónicas y metalogénicas

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Víctor Maksaev

2009-07-01

Full Text Available New U-Pb zircon dating of volcamc intercalations in the lower conglomeratic part of the Cerrillos Formation shows that its deposition extended in time at least from 110.7±1.7 to 99.7±1.6 Ma. The significantly younger U-Pb zircon age of 69.5±1.0 Ma obtained for the upper volcamc part of the Cerrillos Formation suggests recurrence of volcanism in the Late Cretaceous instead of continual volcanic activity. A minimum late Maastrichtian age for the Cerrillos Formation and its initial deformation was determined by the U-Pb zircon age range from 66.9±1.0 to 65.2±1.0 Ma for the lower part of the unconformably overlying Hornitos Formation. The new U-Pb data for the Cerrillos and Hornitos formations poses questions about the Campanian-Maastrichtian age range currently ascribed to the latter. The lower part of the Cerrillos Formation represents a major change in the sedimentary regime from previous marine carbonate sedimentation in a back-arc basin until the late Aptian to subsequent coarse alluvial sedimentation and volcanism since the early Albian. The lower part of the Cerrillos Formation is interpreted as the development of coalescent alluvial fans thinning inland, accompanied by volcanism. These developed as the result of transpressive deformation and uplift of the area of the current Coastal Cordillera by late Aptian, leading to subsequent active erosion and sedimentation inland, along with the eastward shift of the magmatic foci in the Región . Amineralizing period of Cu-Au porphyries overlaps in time with the deposition of the Cerrillos Formation in northern Chile; marking also a significant change in the metallogeny of the Andes of northern Chile.Nuevas dataciones U-Pb obtenidas para intercalaciones volcánicas en la parte inferior conglomerádica de la Formacion Cerrillos muestran que su depositacion se extendió en el tiempo al menos desde 110,7±1,7 hasta 99,7±1,6 Ma. La edad U-Pb significativamente más joven de 69,5±1,0 Ma obtenida

A promising location in Patagonia for paleoclimate and paleoenvironmental reconstructions revealed by shallow firn core from Monte San Valentin (Northern patagonia Icefield, Chile)

DEFF Research Database (Denmark)

Vimeux, F.; de Angelis, M.; Ginot, P.

2008-01-01

temperature is -11.9°C at 10-m depth allowing to expect well preserved both chemical and isotopic signals, unperturbed by water percolation. The dating of the core, on the basis of a multi-proxy approach combining annual layer counting and radionuclide measurements, shows that past environment and climate can......The study of past climate variability from ice core investigations has been largely developed both in polar areas over the past decades and, more recently, in tropical regions, specifically along the South American Andes between 0° and 20°S. However a large gap still remains at mid......-latitudes in the Southern Hemisphere. In this framework, a 15.3-m long shallow firn core has been extracted in March 2005 from the summit plateau of Monte San Valentín (3747 m, 46°35'S, 73°19'W) in the Northern Patagonia Icefield to test its potential for paleoclimate and paleoenvironmental reconstructions. The firn...

Rock avalanches clusters along the northern Chile coastal scarp

Science.gov (United States)

Crosta, G. B.; Hermanns, R. L.; Dehls, J.; Lari, S.; Sepulveda, S.

2017-07-01

Rock avalanche clusters can be relevant indicators of the evolution of specific regions. They can be used to define: the type and intensity of triggering events, their recurrence and potential probability of occurrence, the progressive damage of the rock mass, the mechanisms of transport and deposition, as well as the environmental conditions at the time of occurrence. This paper tackles these subjects by analyzing two main clusters of rock avalanches (each event between 0.6 and 30 Mm3), separated by few kilometers and located along the coastal scarp of Northern Chile, south of Iquique. It lies, hence, within a seismic area characterized by a long seismic gap that ended on April 1st, 2014 with a Mw 8.2 earthquake. The scar position, high along the coastal cliff, supports seismic triggering for these clusters. The deposits' relative positions are used to obtain the sequence of rock avalanching events for each cluster. The progressive decrease of volume in the sequence of rock avalanches forming each cluster fits well the theoretical models for successive slope failures. These sequences seem to agree with those derived by dating the deposits with ages spanning between 4 kyr and 60 kyr. An average uplift rate of 0.2 mm/yr in the last 40 kyr is estimated for the coastal plain giving a further constraint to the rock avalanche deposition considering the absence of reworking of the deposits. Volume estimates and datings allow the estimation of an erosion rate contribution of about 0.098-0.112 mm km- 2 yr- 1 which is well comparable to values presented in the literature for earthquake induced landslides. We have carried out numerical modeling in order to analyze the mobility of the rock avalanches and examine the environmental conditions that controlled the runout. In doing so, we have considered the sequence of individual rock avalanches within the specific clusters, thus including in the models the confining effect caused by the presence of previous deposits. Bingham

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.

Intraseasonal variability of organized convective systems in the Central Andes: Relationship to Regional Dynamical Features

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Mohr, K. I.; Slayback, D. A.; Nicholls, S.; Yager, K.

2013-12-01

The Andes extend from the west coast of Colombia (10N) to the southern tip of Chile (53S). In southern Peru and Bolivia, the Central Andes is split into separate eastern and western cordilleras, with a high plateau (≥ 3000 m), the Altiplano, between them. Because 90% of the Earth's tropical mountain glaciers are located in the Central Andes, our study focuses on this region, defining its zonal extent as 7S-21S and the meridional extent as the terrain 1000 m and greater. Although intense convection occurs during the wet season in the Altiplano, it is not included in the lists of regions with frequent or the most intense convection. The scarcity of in-situ observations with sufficient density and temporal resolution to resolve individual storms or even mesoscale-organized cloud systems and documented biases in microwave-based rainfall products in poorly gauged mountainous regions have impeded the development of an extensive literature on convection and convective systems in this region. With the tropical glaciers receding at unprecedented rates, leaving seasonal precipitation as an increasingly important input to the water balance in alpine valley ecosystems and streams, understanding the nature and characteristics of the seasonal precipitation becomes increasingly important for the rural economies in this region. Previous work in analyzing precipitation in the Central Andes has emphasized interannual variability with respect to ENSO, this is the first study to focus on shorter scale variability with respect to organized convection. The present study took advantage of the University of Utah's Precipitation Features database compiled from 14 years of TRMM observations (1998-2012), supplemented by field observations of rainfall and streamflow, historical gauge data, and long-term WRF-simulations, to analyze the intraseasonal variability of precipitating systems and their relationship regional dynamical features such as the Bolivian High. Through time series and

Absolute paleointensity of the Earth's magnetic field during Jurassic: case study of La Negra Formation (northern Chile)

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Morales, Juan; Goguitchaichvili, Avto; Alva-Valdivia, Luis M.; Urrutia-Fucugauchi, Jaime

2003-08-01

We carried out a detailed rock-magnetic and paleointensity study of the ˜187-Ma volcanic succession from northern Chile. A total of 32 consecutive lava flows (about 280 oriented standard paleomagnetic cores) were collected at the Tocopilla locality. Only 26 samples with apparently preserved primary magnetic mineralogy and without secondary magnetization components were pre-selected for Thellier paleointensity determination. Eleven samples coming from four lava flows yielded reliable paleointensity estimates. The flow-mean virtual dipole moments range from 3.7±0.9 to 7.1±0.5 (10 22 A m 2). This corresponds to a mean value of (5.0±1.8)×10 22 A m 2, which is in reasonably good agreement with other comparable quality paleointensity determinations from the Middle Jurassic. Given the large dispersion and the very poor distribution of reliable absolute intensity data, it is hard to draw any firm conclusions regarding the time evolution of the geomagnetic field. To cite this article: J. Morales et al., C. R. Geoscience 335 (2003).

Metals content in surface waters of an upwelling system of the northern Humboldt Current (Mejillones Bay, Chile)

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Valdés, Jorge; Román, Domingo; Alvarez, Gabriel; Ortlieb, Luc; Guiñez, Marcos

Physical-chemical parameters (temperature, salinity, dissolved oxygen, nutrients, and chlorophyll concentration) of surface waters were used to evaluate the influence of biological and physical processes over the metal concentrations (Cd, Ni, V, Mo, Mn, and Fe) in different periods of a normal annual cycle (June 2002 and April 2003), in Mejillones Bay (23° S), one of northern Chile's strongest upwelling cells. Two points were sampled every 2 months, but statistical analysis of these parameters did not show any spatial differences in surface water composition (annual average) in this bay. The order of total and dissolved metals by abundance (annual mean) in the Mejillones Bay surface waters during the sampling period was Cd Oxygen Minimum Zone which characterizes the Mejillones bay should have an important influence on surface distribution of trace metals and can explain the high temporal variability observed in most of the metals analyzed in this work. A two-box conceptual model is proposed to suggest possible influences on metals in surface waters of this coastal ecosystem.

Photosynthetic performance of Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae in a high-elevation site of the Andes of central Chile Desempeño fotosintético de Colobanthus quitensis (Kunth Bartl. (Caryophyllaceae en los Andes de Chile central

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M. ANGÉLICA CASANOVA-KATNY

2006-03-01

Full Text Available Photosynthesis of Colobanthus quitensis and mesoclimatic conditions of air temperature and light intensity during the growing season were investigated at 2,650 m in the central Chilean Andes. On three typical days of the growing period (January, March and May, CO2 exchange and chlorophyll fluorescence were measured. In addition, a series of fluorescence response curves with increasing light intensity at different temperatures were performed to estimate the propensity of Andean C. quitensis populations to be photoinhibited. Net Photosynthesis (Pn was low (ca. 2.0 mmol CO2 m-2s-1 during the morning and noon in days with high photosynthetic active radiation (PAR, above 1,800 mmol photons m-2s-1. Pn increased in the afternoon (3.5-4.8 mmol CO2 m-2s-1 when PAR decreased to ca. 1,400 mmol photons m-2s-1 and leaf temperature were ca. 20 °C. Fv/Fm in the diurnal periods was between 0.7-0.75 without evidence of photoinhibition. Leaves at 15 and 22 °C exhibited a slow decrease of F PSII with the increase in actinic light intensity, although the fraction of reaction centers open (expressed by qP remained higher at 22 °C. NPQ was saturated at light intensities close to 500 mmol photons m-2s-1 in leaves at 22 °C and at higher intensities at 15 °C, suggesting that NPQ could be a mechanism of energy dissipation at high light intensity and high leaf temperature in the field. Our results indicated that C. quitensis is not photodamaged during the diurnal cycle and that the low Pn registered during some diurnal periods are likely to be related with photorespiration, which has been suggested as an efficient protective mechanism for photoinhibition in alpine plants. Our results are also compared with the photosynthetic performance of C. quitensis populations from the maritime AntarcticSe estudió la fotosíntesis de Colobanthus quitensis y las condiciones mesoclimáticas de temperatura del aire e intensidad lumínica a 2.650 m en los Andes de Chile central. Se

Andes 1997 Gravity Data

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National Oceanic and Atmospheric Administration, Department of Commerce — The Central Andes gravity data (6,151 records) were compiled by Professor Gotze and the MIGRA Group. This data base was received in April, 1997. Principal gravity...

The 2010-2015 megadrought in central Chile: impacts on regional hydroclimate and vegetation

Science.gov (United States)

Garreaud, René D.; Alvarez-Garreton, Camila; Barichivich, Jonathan; Boisier, Juan Pablo; Christie, Duncan; Galleguillos, Mauricio; LeQuesne, Carlos; McPhee, James; Zambrano-Bigiarini, Mauricio

2017-12-01

Since 2010 an uninterrupted sequence of dry years, with annual rainfall deficits ranging from 25 to 45 %, has prevailed in central Chile (western South America, 30-38° S). Although intense 1- or 2-year droughts are recurrent in this Mediterranean-like region, the ongoing event stands out because of its longevity and large extent. The extraordinary character of the so-called central Chile megadrought (MD) was established against century long historical records and a millennial tree-ring reconstruction of regional precipitation. The largest MD-averaged rainfall relative anomalies occurred in the northern, semi-arid sector of central Chile, but the event was unprecedented to the south of 35° S. ENSO-neutral conditions have prevailed since 2011 (except for the strong El Niño in 2015), contrasting with La Niña conditions that often accompanied past droughts. The precipitation deficit diminished the Andean snowpack and resulted in amplified declines (up to 90 %) of river flow, reservoir volumes and groundwater levels along central Chile and westernmost Argentina. In some semi-arid basins we found a decrease in the runoff-to-rainfall coefficient. A substantial decrease in vegetation productivity occurred in the shrubland-dominated, northern sector, but a mix of greening and browning patches occurred farther south, where irrigated croplands and exotic forest plantations dominate. The ongoing warming in central Chile, making the MD one of the warmest 6-year periods on record, may have also contributed to such complex vegetation changes by increasing potential evapotranspiration. We also report some of the measures taken by the central government to relieve the MD effects and the public perception of this event. The understanding of the nature and biophysical impacts of the MD helps as a foundation for preparedness efforts to confront a dry, warm future regional climate scenario.

Decomposition of sinking proteinaceous material during fall in the oxygen minimum zone off northern Chile

Science.gov (United States)

Pantoja, Silvio; Sepúlveda, Julio; González, Humberto E.

2004-01-01

We investigated the fate of sinking proteinaceous material in the oxygen minimum zone off northern Chile by deploying sediment traps at 30 m (base of the oxygenated layer) and 300 m (bottom of the O 2-depleted layer) during a 3-day experiment. Most of photosynthetically produced protein (82%) degraded in the top 30 m; an additional 15% decayed between 30 and 300 m, within the suboxic zone; and ca. 1% reached surface sediments at 1200 m depth. Sinking protein remained diagenetically labile in the top 300-m of the water column, as indicated by degradation indices and degradation rate constants of trap material, both characteristic of fresh material. We conclude that particulate protein degradation is not affected by the occurrence of the suboxic layer between 30 and 300 m in the water column. This conclusion is consistent with a model of degradation of particulate protein controlled by extracellular enzymatic hydrolysis and not dependent on O 2 availability. Assuming that our fall results are representative for an annual cycle and the whole oxygen minimum zone, suboxic decay of sinking protein in the oxygen minimum zone could support a production of 2 Tg N 2 yr -1, consistent with independent estimates of denitrification rates in the area.

Mammalian carnivore occupancy is inversely related to presence of domestic dogs in the high Andes of Ecuador.

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Galo Zapata-Ríos

Full Text Available Although the Andes have long been occupied by people, habitat loss, fragmentation through deforestation, and other human activities such as introduction of invasive species have increased drastically during the past century. The Ecuadorian Andes are considered a biodiversity hotspot. However, the fauna and threats to the region are poorly studied, and understanding of factors that shape the distribution of species in habitats disturbed by human activities is needed to identify and mitigate region-wide threats to wildlife. We evaluated factors associated with patterns of occurrence of Andean carnivores in landscapes of the northern Ecuadorian Andes, particularly habitat loss, fragmentation, and occupancy of domestic dogs, and determined whether thresholds occurred for these factors beyond which carnivore occurrence declined markedly. Five study areas (each 20 x 20 km were surveyed with a total effort of 2,800 camera trap nights. Occupancies of four of the eight carnivores known from the region were best predicted by occupancy of domestic dogs rather than measures of habitat loss and fragmentation [Andean fox (Pseudalopex culpaeus, puma (Puma concolor, striped hog-nosed skunk (Conepatus semistriatus, and Andean bear (Tremarctos ornatus]. The two largest carnivores, puma and Andean bear, demonstrated significant threshold responses to the presence of domestic dogs at two sites. Four smaller carnivores were recorded too infrequently to model occupancy, and at least two of these species appear to be in decline. The magnitude of domestic dog impacts on native species in tropical areas like the Ecuadorian Andes currently are not recognized. Results of our study indicate that small and large carnivores are in urgent need of conservation and clearly point to dogs as a significant threat to a broad range of native species.

Chile's pipelines - who's out in the cold?

International Nuclear Information System (INIS)

Bellhouse, G.

1998-01-01

There is a battle on in Northern Chile to supply the region with gas and electricity. Two pipelines and a transmission line are being built, but there is insufficient demand to merit the construction of all of these projects. It is widely believed that the first pipeline to be finished will be the overall winner, but the situation is not that simple. A more sensible conclusion could be the merger of the two pipeline projects, rationalising supply of gas to the region. (Author)

ASTER Andes

Science.gov (United States)

2000-01-01

In this image of the Andes along the Chile-Bolivia border, the visible and infrared data have been computer enhanced to exaggerate the color differences of the different materials. The scene is dominated by the Pampa Luxsar lava complex, occupying the upper right two-thirds of the scene. Lava flows are distributed around remnants of large dissected cones, the largest of which is Cerro Luxsar. On the middle left edge of the image are the Olca and Parumastrato volcanoes, which appear in blue due to a lack of vegetation (colored red in this composite). This image covers an area 60 kilometers (37 miles) wide and 60 kilometers (37 miles) long in three bands of the reflected visible and infrared wavelength region. It was acquired on April 7, 2000.The image is located at 21 degrees south latitude, 68.3 degrees west longitude. Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of International Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. science team leader; Moshe Pniel of JPL is the project manager. ASTER is the only high-resolution imaging sensor on Terra. The primary goal of the ASTER mission is to obtain high-resolution image data in 14 channels over the entire land surface, as well as black and white stereo images. With revisit time of between 4 and 16 days, ASTER will provide the capability for repeat coverage of changing areas on Earth's surface.The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping and monitoring dynamic conditions and temporal change. Examples of applications include monitoring glacial advances and retreats

Contrasting Climate Change Impact on River Flow from Glacierised Catchments in the Himalayan and Andes Mountains

Science.gov (United States)

Pellicciotti, F.; Ragettli, S.; Immerzeel, W. W. W.

2016-12-01

Glaciers and glacierised catchments in mountainous regions react to a changing climate in different manners depending on climate and glacier characteristics. Despite the key role of mountain ranges as natural water towers, their hydrological balance and future changes in glacier runoff associated with climate warming remain poorly understood because of high meteorological variability, physical inaccessibility and the complex interplay between climate, cryosphere and hydrological processes. We use a state-of-the art glacio-hydrological model informed by data from high altitude observations and the latest CMIP5 climate change scenarios to quantify the climate change impact on glaciers and runoff for two contrasting catchments vulnerable to changes in the cryosphere. The two catchments are located in the Central Andes of Chile and in the Nepalese Himalaya in close vicinity of densely populated areas. Although both sites are projected to experience a strong decrease in glacier area, they show remarkably different hydrological responses. Icemelt is on a rising limb in Langtang at least until 2041-2050 and starts to decrease afterwards, while in Juncal icemelt was already beyond its tipping point at the beginning of the 21st century. This contrasting response can be explained by differences in the elevation distribution of the glaciers in the two regions. In Juncal, many glaciers are melting up to the highest elevations already during the reference period (2000-2010) and increasing melt rates due to higher air temperatures cannot compensate the loss of glacier area. In Langtang, large sections of the glaciers at high elevations are currently not exposed to melt, but will be in the future, thus compensating for the loss of glacier area at lower elevations. As a result of these changes and projected changes in precipitation, in Juncal runoff will sharply decrease in the future and the runoff seasonality is sensitive to projected climatic changes. In Langtang, future water

Osseous skeletal material and fish scales in marine sediments under the oxygen minimum zone off northern and central Chile

Science.gov (United States)

Milessi, Andrés C.; Sellanes, Javier; Gallardo, Víctor A.; Lange, Carina B.

2005-08-01

The significance of whale falls for the study of the biogeography, evolution and biodiversity of deep-sea biota has been recently recognized by international programs since large carcasses are known to give rise to biogenic chemosynthetic ecosystems. However, the plain accumulation of smaller bone material in the shallower settings of the continental shelf and upper slope under the hypoxic conditions of the Oxygen Minimum Zone (OMZ), has received much less attention. Here we describe new findings of skeletal material and fish scales in marine sediments under the OMZ off northern and central Chile which, combined with previous reports for the study area, lead us to suggest the existence of a band in the benthos of accumulation of bones and scales extending at least twenty degrees in latitude (18-38° S). Future studies should focus on the characterization of biotic communities living upon these resources in order to elucidate their peculiarities and importance in the Eastern South Pacific.

Weather Type classification over Chile; patterns, trends, and impact in precipitation and temperature

Science.gov (United States)

Frias, T.; Trigo, R. M.; Garreaud, R.

2009-04-01

The Andes Cordillera induces considerable disturbances on the structure and evolution of the pressure systems that influences South America. Different weather types for southern South America are derived from the daily maps of geopotential height at 850hPa corresponding to a 42 year period, spanning from 1958 to 2000. Here we have used the ECWMF ERA-40 reanalysis dataset to construct an automated version of the Lamb Weather type (WTs) classification scheme (Jones et al., 1993) developed for the UK. We have identified 8 basic WTs (Cyclonic, Anticyclonic and 6 main directional types) following a similar methodology to that previously adopted by Trigo and DaCamara, 2000 (for Iberia). This classification was applied to two regions of study (CLnorth and CLsouth) which differ 20° in latitude, so that the vast Chile territory could be covered. Then were assessed the impact of the occurrence of this weather types in precipitation in Chile, as well as in the distribution of precipitation and temperature fields (reanalysis data) in southern half of South America. The results allow to conclude that the precipitation in central region of Chile is largely linked with the class occurrence (concerning CLnorth) of cyclonic circulation and of West quadrant (SW, W and NW), despite of it's relatively low frequency. In CLsouth, for its part, it is verified that the most frequent circulation is from the west quadrant, although the associated amount of rainfall is lower than in CLnorth. There was also a general decrease of precipitation at local weather stations chosen in the considered period of study, particularly in austral winter.

The high Andes, gene flow and a stable hybrid zone shape the genetic structure of a wide-ranging South American parrot

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Schaefer H Martin

2011-06-01

Full Text Available Abstract Background While the gene flow in some organisms is strongly affected by physical barriers and geographical distance, other highly mobile species are able to overcome such constraints. In southern South America, the Andes (here up to 6,900 m may constitute a formidable barrier to dispersal. In addition, this region was affected by cycles of intercalating arid/moist periods during the Upper/Late Pleistocene and Holocene. These factors may have been crucial in driving the phylogeographic structure of the vertebrate fauna of the region. Here we test these hypotheses in the burrowing parrot Cyanoliseus patagonus (Aves, Psittaciformes across its wide distributional range in Chile and Argentina. Results Our data show a Chilean origin for this species, with a single migration event across the Andes during the Upper/Late Pleistocene, which gave rise to all extant Argentinean mitochondrial lineages. Analyses suggest a complex population structure for burrowing parrots in Argentina, which includes a hybrid zone that has remained stable for several thousand years. Within this zone, introgression by expanding haplotypes has resulted in the evolution of an intermediate phenotype. Multivariate regressions show that present day climatic variables have a strong influence on the distribution of genetic heterogeneity, accounting for almost half of the variation in the data. Conclusions Here we show how huge barriers like the Andes and the regional environmental conditions imposed constraints on the ability of a parrot species to colonise new habitats, affecting the way in which populations diverged and thus, genetic structure. When contact between divergent populations was re-established, a stable hybrid zone was formed, functioning as a channel for genetic exchange between populations.

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 �

Population dynamics of the rat Microryzomys minutus (Rodentia: Muridae in the Venezuelan Andes

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Daniel R Cabello

2006-06-01

Full Text Available The population dynamics of the small forest rice rat Microryzomys minutus, a murid rodent that occurs in the high altitudes of the northern and central Andes, was studied in disturbed and primary environments in a cloud forest of the Venezuelan Andes (Juan Pablo Peñaloza National Park, 8º11’N, 71º49’W. We collected 121 animals (66♀♀ and 55♂♂ between 1995 and 1998, using pitfall traps with formalin. Adult males were heavier than adult females. Relative abundance was much greater in the disturbed environments (over 10 individuals in some periods than in the primary cloud forest: 4-8 individuals. In the disturbed environments, the rats were extremely abundant in the first sampling period, and less frequent afterwards. In the cropland, abundance showed some fluctuations during the study and displayed two small abundance peaks in March-June 1997 and 1998. In the mined area, the rats had irregular fluctuations until March-June 1997 and were not recorded in July-October 1997. The occurrence of this rat in both disturbed and natural habitats confirms the wide ecological tolerance of this species. Rev. Biol. Trop. 54(2: 651-. Epub 2006 Jun 01.Se analizó la dinámica poblacional de las pequeñas ratas silvestres del arroz Microryzomys minutus en ambientes alterados y primarios, en un bosque nublado de los Andes venezolanos. El estudio fue basado en 121 animales (66♀♀ y 55♂♂ recolectados entre 1995 y 1998, usando trampas que contenían formalina. Esta especie está presente en ambos hábitats lo que confirma su amplia tolerancia ecológica. La abundancia poblacional fue mayor en ambientes alterados que en los no alterados. M. minutus presenta dimorfismo sexual en el peso: los machos son más pesados que las hembras.

Presencia del género Stegomastodon entre los restos fósiles de mastodontes de Chile (Gomphotheriidae, Pleistoceno superior

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Alberdi, M. T.

2005-04-01

Full Text Available New Gomphotheriidae fossils encouraged the authors to study recently obtained them and review some others materials of this family that were classified in 2000 as Cuvieronius hyodon (Fischer. Together with new tusks remains, the recovery of the anterior portion of the cranial symphysis (alveolar zone of a skull from Taguatagua is remarkable. The morphology of the available tusks and the characteristics of the anterior part of the symphysis allow the assignment of these remains to Stegomastodon. The occurrence of this genus at the end of the Pleistocene in Chile is established. Fossils are compared with others remains from South America and probable dispersal routes through the Andes cordillera are discussed.Nuevos materiales fósiles de Gomphotheriidae obtenidos recientemente, estimularon a los autores a estudiarlos y a revisar algunos otros restos de esta familia, que habían sido asignados, el año 2000, a Cuvieronius hyodon (Fischer. Junto a nuevos restos de defensas, destaca la recuperación de la parte anterior de la sínfisis craneal (zona alveolar de un cráneo de Taguatagua. La morfología de las defensas disponibles y las características de la porción anterior de la sínfisis, permiten asignar estos materiales al género Stegomastodon, fundamentando así la presencia de este género en el Pleistoceno terminal de Chile. Se comparan con otros restos de América del Sur y se discuten las probables vías de migración de estos mamíferos a través de la cordillera de los Andes.

Diagenetic changes in Concholepas concholepas shells (Gastropoda, Muricidae) in the hyper-arid conditions of Northern Chile - implications for palaeoenvironmental reconstructions

Science.gov (United States)

Guzmán, N.; Dauphin, Y.; Cuif, J. P.; Denis, A.; Ortlieb, L.

2009-02-01

Variations in the chemical composition of fossil biogenic carbonates, and in particular of mollusc shells, have been used in a range of palaeoenvironmental reconstructions. It is of primary importance, therefore, to detect and understand the diagenetic processes that may modify the original chemical signature. This microstructural and biogeochemical study focuses on modern and fossil (Holocene and Pleistocene) shells of a littoral gastropod of Northern Chile, and on the characterization of mineral component transformations at the nanometric scale and concomitant intracrystalline organic compound modifications. The inner aragonite layer of the shell exhibits more complex deteriorations than the calcite layer. This preliminary study confirms that physical and chemical alterations of various components of mollusc shell biocrystals are complex and might manifest in different ways even within a single individual. The single criterion of determining the mineralogical composition to verify the conservation state of shell samples is insufficient.

Listening carefully. Unique observations of harmonic tremor at Lascar volcano, Chile

Energy Technology Data Exchange (ETDEWEB)

Hellweg, M. [Stuttgart Univ., Stuttgart (Germany). Inst. fuer Geophysik

1999-06-01

During the deployment of Proyecto de Investigacion Sismologica de la Cordillera Occidental 94 (PISCO '94) in the Atacama Desert of Northern Chile, a broadband seismic station and a network od three short-period three-component stations were installed around the active volcano Lascar (Chile). The paper analyzes the resulting data set, which include a sequence of harmonic tremor with a fundamental at a about 0.63 Hz and up to 30 overtones lasting 18 h. Power spectra and spectrograms of Lascar's harmonic tremor from the various stations demonstrate that the frequencies recorded cannot be explained as path effects, and must therefore be attributed to mechanisms at or near the source.

The 2010–2015 megadrought in central Chile: impacts on regional hydroclimate and vegetation

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R. D. Garreaud

2017-12-01

Full Text Available Since 2010 an uninterrupted sequence of dry years, with annual rainfall deficits ranging from 25 to 45 %, has prevailed in central Chile (western South America, 30–38° S. Although intense 1- or 2-year droughts are recurrent in this Mediterranean-like region, the ongoing event stands out because of its longevity and large extent. The extraordinary character of the so-called central Chile megadrought (MD was established against century long historical records and a millennial tree-ring reconstruction of regional precipitation. The largest MD-averaged rainfall relative anomalies occurred in the northern, semi-arid sector of central Chile, but the event was unprecedented to the south of 35° S. ENSO-neutral conditions have prevailed since 2011 (except for the strong El Niño in 2015, contrasting with La Niña conditions that often accompanied past droughts. The precipitation deficit diminished the Andean snowpack and resulted in amplified declines (up to 90 % of river flow, reservoir volumes and groundwater levels along central Chile and westernmost Argentina. In some semi-arid basins we found a decrease in the runoff-to-rainfall coefficient. A substantial decrease in vegetation productivity occurred in the shrubland-dominated, northern sector, but a mix of greening and browning patches occurred farther south, where irrigated croplands and exotic forest plantations dominate. The ongoing warming in central Chile, making the MD one of the warmest 6-year periods on record, may have also contributed to such complex vegetation changes by increasing potential evapotranspiration. We also report some of the measures taken by the central government to relieve the MD effects and the public perception of this event. The understanding of the nature and biophysical impacts of the MD helps as a foundation for preparedness efforts to confront a dry, warm future regional climate scenario.

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

Spectral scaling of the aftershocks of the Tocopilla 2007 earthquake in northern Chile

Science.gov (United States)

Lancieri, M.; Madariaga, R.; Bonilla, F.

2012-04-01

We study the scaling of spectral properties of a set of 68 aftershocks of the 2007 November 14 Tocopilla (M 7.8) earthquake in northern Chile. These are all subduction events with similar reverse faulting focal mechanism that were recorded by a homogenous network of continuously recording strong motion instruments. The seismic moment and the corner frequency are obtained assuming that the aftershocks satisfy an inverse omega-square spectral decay; radiated energy is computed integrating the square velocity spectrum corrected for attenuation at high frequencies and for the finite bandwidth effect. Using a graphical approach, we test the scaling of seismic spectrum, and the scale invariance of the apparent stress drop with the earthquake size. To test whether the Tocopilla aftershocks scale with a single parameter, we introduce a non-dimensional number, ?, that should be constant if earthquakes are self-similar. For the Tocopilla aftershocks, Cr varies by a factor of 2. More interestingly, Cr for the aftershocks is close to 2, the value that is expected for events that are approximately modelled by a circular crack. Thus, in spite of obvious differences in waveforms, the aftershocks of the Tocopilla earthquake are self-similar. The main shock is different because its records contain large near-field waves. Finally, we investigate the scaling of energy release rate, Gc, with the slip. We estimated Gc from our previous estimates of the source parameters, assuming a simple circular crack model. We find that Gc values scale with the slip, and are in good agreement with those found by Abercrombie and Rice for the Northridge aftershocks.

Changes in Tsunami Risk Perception in Northern Chile After the April 1 2014 Tsunami

Science.gov (United States)

Carvalho, L.; Lagos, M.

2016-12-01

Tsunamis are a permanent risk in the coast of Chile. Apart from that, the coastal settlements and the Chilean State, historically, have underestimated the danger of tsunamis. On April 1 2014, a magnitude Mw 8.2 earthquake and a minor tsunami occurred off the coast of northern Chile. Considering that over decades this region has been awaiting an earthquake that would generate a large tsunami, in this study we inquired if the familiarity with the subject tsunami and the lack of frequent tsunamis or occurrence of non-hazardous tsunamis for people could lead to adaptive responses to underestimate the danger. The purpose of this study was to evaluate the perceived risk of tsunami in the city of Arica, before and after the April 1 2014 event. A questionnaire was designed and applied in two time periods to 547 people living in low coastal areas in Arica. In the first step, the survey was applied in March 2014. While in step 2, new questions were included and the survey was reapplied, a year after the minor tsunami. A descriptive analysis of data was performed, followed by a comparison between means. We identified illusion of invulnerability, especially regarding to assessment that preparedness and education actions are enough. Answers about lack of belief in the occurrence of future tsunamis were also reported. At the same time, there were learning elements identified. After April 1, a larger number of participants described self-protection actions for emergency, as well as performing of preventive actions. In addition, we mapped answers about the tsunami danger degree in different locations in the city, where we observed a high knowledge of it. When compared with other hazards, the concern about tsunamis were very high, lower than earthquakes hazard, but higher than pollution, crime and rain. Moreover, we identified place attachment in answers about sense of security and affective bonds with home and their location. We discussed the relationship between risk perception

A review of the Hexactinellida (Porifera) of Chile, with the first record of Caulophacus Schulze, 1885 (Lyssacinosida: Rossellidae) from the Southeastern Pacific Ocean.

Science.gov (United States)

Reiswig, Henry M; Araya, Juan Francisco

2014-12-02

All records of the 15 hexactinellid sponge species known to occur off Chile are reviewed, including the first record in the Southeastern Pacific of the genus Caulophacus Schulze, 1885, with the new species Caulophacus chilense sp. n. collected as bycatch in the deep water fisheries of the Patagonian toothfish Dissostichus eleginoides Smitt, 1898 off Caldera (27ºS), Region of Atacama, northern Chile. All Chilean hexactinellid species occur in bathyal to abyssal depths (from 256 up to 4142 m); nine of them are reported for the Sala y Gomez and Nazca Ridges, with one species each in the Juan Fernandez Archipelago and Easter Island. The Chilean hexactinellid fauna is still largely unknown, consisting of only 2.5 % of the known hexactinellid extant species. Further studies and deep water sampling are essential to assess their ecology and distribution, particularly in northern Chile.

A new species of iguanid lizard, genus Stenocercus (Squamata, Iguania), from the Central Andes in Peru.

Science.gov (United States)

Venegas, Pablo J; Echevarría, Lourdes Y; García-Burneo, Karla; Koch, Claudia

2016-12-04

We describe a new species of Stenocercus from the montane forest of the right margin of the Marañón river in the northern portion of the Central Andes in northern Peru (Amazonas and La Libertad departments), at elevations ranging from 2300 to 3035 m. Stenocercus omari sp. nov. differs from other Stenocercus species, with the exception of S. amydrorhytus, S. chrysopygus, S. cupreus, S. johaberfellneri, S. latebrosus, S. melanopygus, S. modestus, S. ornatissimus, S. orientalis, and S. stigmosus, by having granular scales on the posterior surfaces of thighs, a conspicuous antehumeral fold and by lacking a vertebral crest. However, Stenocercus omari sp. nov. is easily distinguished from the aforementioned species, except S. orientalis, by the presence of prominently keeled dorsal head scales. The new species differs from S. orientalis by lacking a prominent oblique neck fold and by having a distinct deep postfemoral mite pocket.

Gender relations and masculinity in northern Chile mining areas: ethnography in schoperías Relações de género e masculinidade em áreas de mineração do norte do Chile: etnografia em schoperías

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Jaime Barrientos Delgado

2011-06-01

Full Text Available This paper deals with an ethnography aimed at describing and understanding the gendered organization of schopería life and masculinity in northern Chile. Schoperías are characterized physically and socially and the effects these premises have on gender relations and masculinity assigned to them by waitresses and clients are studied. Schoperías are beer halls, mainly for men, served by women, located in cities near copper mines in Chile. They are strongly gendered and classed places. Schoperías are reference scenarios for men and their performance; they are premises that privilege masculine socialization and heterosexual hegemonic masculine performance. Paradoxically, they are at the same time unique places where male friendship and complicity take place, allowing homosociability and the expression of a certain type of affection and feelings among men.O artigo baseia-se numa etnografia com a qual se pretendeu descrever e compreender a organização das schoperías em função do género e a masculinidade no Norte do Chile. As schoperías são caraterizadas física e socialmente e são estudados os efeitos que estes locais produzem nas relações de género e na masculinidade que lhes é atribuída pelas empregadas e pelos clientes. As schoperías são cervejarias destinadas sobretudo aos homens, que são servidos por mulheres, localizadas em cidades próximas de minas de cobre no Chile. São lugares fortemente marcados pelo género e pela classe. As schoperías são cenários de referência para os homens e a sua performance; são locais que privilegiam a socialização masculina e a performance masculina heterossexual e hegemónica. Paradoxalmente, são ao mesmo tempo lugares singulares onde a amizade e a cumplicidade masculinas têm lugar, permitindo a homossociabilidade e a expressão de um certo tipo de afeto e sentimentos entre homens.

The Southern Central Andes vertical axis tectonic rotations: relations with the deformation pattern Rotaciones tectónicas según ejes verticales en los Andes Centrales del Sur: relaciones con el patrón de deformación

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Claudia Prezzi

2012-05-01

progreso del conocimiento de los períodos de deformación en los Andes, permitiendo un análisis más detallado de la distribución espacial y temporal de las rotaciones detectadas. En este trabajo se recopilan y analizan los datos paleomagnéticos cenozoicos disponibles para la región que se extiende entre los 19° y los 27,5°S. Los resultados obtenidos sugieren la posible existencia de distintos dominios rotacionales con diferentes características. Aparentemente existe una estrecha correlación entre el estilo y el patrón espacial y temporal de deformación y la magnitud de las rotaciones según ejes verticales. Sin embargo, para investigar de manera más detallada dicha relación, es necesario disponer de un mayor número de datos paleomagnéticos. Especialmente, deberían llevarse a cabo nuevos estudios paleomagnéticos de rocas paleógenas del Altiplano-Puna, de rocas paleógenas y neógenas de la Cordillera Oriental y de rocas neógenas del norte de Chile.

Sustainable groundwater development under climate change in the Valle de Azapa, northern Chile

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Herrera, P. A.; Balic, I.

2015-12-01

The Valle de Azapa is located at the northern border of the Atacama Desert, which is considered the driest place on earth. Agriculture is the main economic activity of the valley and it is possible due to the exploitation of groundwater pumped from the aquifer of the area, which is replenished by sporadic rainfall that occurred at the Andes. The high demand on the aquifer has generated a situation that is considered as fragile or unsustainable for the future. This situation could be worsened by the forecasted climate change impact on the region, which would result in reductions in precipitation of up to 40% in the next 100 years. This was the main motivation to study the potential impact of climate change on the sustainability of the aquifer under different water demand scenarios through numerical simulations. We model the impact of climate change by generating stochastic precipitation series that consider reductions between 0 and 40% during the next 100 years. We use the precipitation series to estimate recharge rates through a previously calibrated correlation. For each recharge series we consider three different scenarios: reduction, no change and increase in the water demand. We then use a groundwater model to analyze the evolution of the storage and natural discharge of the aquifer. The main conclusion is that even though the aquifer storage is reduced at the end of the analyzed period, it is still significant in comparison to the extracted groundwater. However, the extraction of groundwater significantly reduces and, in some cases, completely eliminates natural discharge such as springs that exist in the area. This indicates that the system reaches a long-term operation state during the simulated period and that discharges from wells are mainly covered by reductions of the natural discharge of the system. We relate this last finding to the concept of the "Water Budget Myth" proposed by Bredehoeft & Papadopulus (1982). We finish by commenting on possible

Microbial eukaryote diversity in the marine oxygen minimum zone off northern Chile

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Parris, Darren J.; Ganesh, Sangita; Edgcomb, Virginia P.; DeLong, Edward F.; Stewart, Frank J.

2014-01-01

Molecular surveys are revealing diverse eukaryotic assemblages in oxygen-limited ocean waters. These communities may play pivotal ecological roles through autotrophy, feeding, and a wide range of symbiotic associations with prokaryotes. We used 18S rRNA gene sequencing to provide the first snapshot of pelagic microeukaryotic community structure in two cellular size fractions (0.2–1.6 μm, >1.6 μm) from seven depths through the anoxic oxygen minimum zone (OMZ) off northern Chile. Sequencing of >154,000 amplicons revealed contrasting patterns of phylogenetic diversity across size fractions and depths. Protist and total eukaryote diversity in the >1.6 μm fraction peaked at the chlorophyll maximum in the upper photic zone before declining by ~50% in the OMZ. In contrast, diversity in the 0.2–1.6 μm fraction, though also elevated in the upper photic zone, increased four-fold from the lower oxycline to a maximum at the anoxic OMZ core. Dinoflagellates of the Dinophyceae and endosymbiotic Syndiniales clades dominated the protist assemblage at all depths (~40–70% of sequences). Other protist groups varied with depth, with the anoxic zone community of the larger size fraction enriched in euglenozoan flagellates and acantharean radiolarians (up to 18 and 40% of all sequences, respectively). The OMZ 0.2–1.6 μm fraction was dominated (11–99%) by Syndiniales, which exhibited depth-specific variation in composition and total richness despite uniform oxygen conditions. Metazoan sequences, though confined primarily to the 1.6 μm fraction above the OMZ, were also detected within the anoxic zone where groups such as copepods increased in abundance relative to the oxycline and upper OMZ. These data, compared to those from other low-oxygen sites, reveal variation in OMZ microeukaryote composition, helping to identify clades with potential adaptations to oxygen-depletion. PMID:25389417

Bacteriohopanepolyols along redox gradients in the Humboldt Current System off northern Chile.

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Matys, E D; Sepúlveda, J; Pantoja, S; Lange, C B; Caniupán, M; Lamy, F; Summons, R E

2017-11-01

Marine oxygen minimum zones (OMZs) are characterized by the presence of subsurface suboxic or anoxic waters where diverse microbial processes are responsible for the removal of fixed nitrogen. OMZs have expanded over past decades and are expected to continue expanding in response to the changing climate. The implications for marine biogeochemistry, particularly nitrogen cycling, are uncertain. Cell membrane lipids (biomarkers), such as bacterial bacteriohopanepolyols (BHPs) and their degradation products (hopanoids), have distinctive structural attributes that convey information about their biological sources. Since the discovery of fossil hopanoids in ancient sediments, the study of BHPs has been of great biogeochemical interest due to their potential to serve as proxies for bacteria in the geological record. A stereoisomer of bacteriohopanetetrol (BHT), BHT II, has been previously identified in OMZ waters and has as been unequivocally identified in culture enrichments of anammox bacteria, a key group contributing to nitrogen loss in marine OMZs. We tested BHT II as a proxy for suboxia/anoxia and anammox bacteria in suspended organic matter across OMZ waters of the Humboldt Current System off northern Chile, as well as in surface and deeply buried sediments (125-150 ky). The BHT II ratio (BHT II/total BHT) increases as oxygen content decreases through the water column, consistent with previous results from Perú, the Cariaco Basin and the Arabian Sea, and in line with microbiological evidence indicating intense anammox activity in the Chilean OMZ. Notably, BHT II is transported from the water column to surface sediments, and preserved in deeply buried sediments, where the BHT II ratio correlates with changes in δ 15 N sediment values during glacial-interglacial transitions. This study suggests that BHT II offers a proxy for past changes in the relative importance of anammox, and fluctuations in nitrogen cycling in response to ocean redox changes through the

First record of folivory on a newly documented host plant for the little known geometrid moth Eupithecia yubitzae Vargas & Parra (Lepidoptera, Geometridae in northern Chile

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Héctor A. Vargas

2015-06-01

Full Text Available The native tree Schinus molle (Anacardiacae is reported for the first time as a host plant for larvae of the little known geometrid moth Eupithecia yubitzae Vargas & Parra (Lepidoptera, Geometridae in the Atacama Desert of northern Chile, based on morphology and DNA barcodes. This discovery importantly expands the host range of E. yubitzae, as previous records were restricted to Fabaceae trees. Larvae were previously known as florivorous, while these were found to be folivorous on S. molle. Furthermore, host-associated cryptic larval polychromatism was detected, as larvae collected on S. molle were found to be mostly pale green, contrasting with the dark yellow ground color of the larvae typically collected on fabaceous host plants.

Glacial recession in the Tropical Andes from the Little Ice Age: the case of Ampato Volcanic Complex (Southern Peru

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Alcalá, J.; Palacios, D.; Zamorano, J. J.

2010-03-01

Data published over the last decade reveal substantial glacial recession in the tropical Andes since the Little Ice Age (LIA), (Ramirez, et al., 2001; Rabatel, et al., 2005; Rabatel, et al., 2008; Vuille, et al., 2008; Hastenrath, 2009; Jomelli, et al., 2009), and a growing rate of recession since the 1980’s caused by global warming (Ramirez, et al., 2001; Vuille, et al., 2008). Today there is great interest in the evolution of these ice masses due to heightened awareness of climate change and of the strategic importance that glaciers have as a hydrologic resource for communities in arid climate zones in the tropical Andes (Mark, 2008; Vuille et al., 2008). Cordillera Blanca forms part of the Andes Mountains of northern Peru, and is a chosen site for many studies on glacier evolution. Vuille et al. 2008 determined that a considerable area of ice mass was lost at Huascarán-Chopicalqui glacier (18% from 1920-1970) and Astesonraju glacier (20% from 1962-2003). Studies at Coropuna volcano, which has the most extensive glacier field in the western range of southern Peru, also report a strong melting trend that began with only minimal recession from 1955-1986 (4%), but increased to 14% from 1986-2007 (Úbeda et al., 2009). Only a few of the Andes glaciers are consistently monitored, and the most comprehensive data are for Chacaltaya and Zongo glaciers (16º S) in Bolivia. Since the maximum LIA, Chacaltaya has lost 89% of its surface area, particularly in recent years. By 1983, the totaled loss was five times the shrinkage for the period 1940-1963 (Ramirez, et al., 2001). Zongo glacier maintained equilibrium from 1956-1975, but later experienced a period dominated by continuous recession (Soruco, et al., 2009). This study expands current knowledge of glacier evolution since the LIA in the Central Volcanic Zone (CVZ; 14º - 27º S) (Stern, 2004) of the Andes. The study site was chosen in an area that had never been used for preliminary research of this type, concretely

Sexual and age differences in ecological variables of the lizard Microlophus atacamensis (Tropiduridae from northern Chile Diferencias sexuales y etárias en variables ecológicas del lagarto Microlophus atacamensis (Tropiduridae del norte de Chile

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MARCELA VIDAL

2002-06-01

Full Text Available Microlophus is a lizard genus of South-America which has many species with sexual size dimorphism. An ecological study was performed on M. atacamensis, a species inhabiting the intertidal zone of the coast of northern Chile. The following questions were addressed: (1 does M. atacamensis exhibit sexual dimorphism? (2 do individuals of different age and sex segregate spatially? (3 do individuals of different age and sex use different type of microhabitat? and (4 do individuals of different sexes exhibit differences in thermoregulatory characteristics? The study was conducted in different localities from northern Chile, which include two types of rocky systems used by this species, a high and a low type. At the moment of lizard capture, type of microhabitat, height of perch, body, air and substrate temperatures, were recorded. Individuals were then measured and weighted, and separated by age class and sex. Results indicate that this species exhibits sexual dimorphism, males being larger. There were no intersexual differences in microhabitat used and height of perch in the high type system, although adults and subadults were spatially segregated from juveniles. In the low type system adult females shared microhabitat with juveniles, a probable consequence of behaviors related to the burying of eggs. There were no differences between sexes in thermal characteristics, and body temperature of lizards showed independence from external thermal conditionsMicrolophus es un género de lagartos Sudamericanos, el cual tiene varias especies que presentan dimorfismo sexual del tamaño. Se realizó un estudio ecológico en Microlophus atacamensis, especie del intermareal de la costa del norte de Chile, para responder a las siguientes preguntas: (1 ¿presenta M. atacamensis dimorfismo sexual? (2 ¿existe segregación espacial entre individuos de diferentes edades y sexos? (3 ¿existe utilización diferencial de los tipos de hábitats, entre individuos de

The finding of eggs of Diphyllobothrium in human coprolites (4.100-1.950 BC from Northern Chile

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Luiz Fernando Ferreira

1984-06-01

Full Text Available Twenty six coprolites from an archaeological site in the province of Iquique, northern Chile, were examined for parasites. Coprolites were found in two excavation units, I and II (Tiliviche site, dated respectively at 5,900 B.C. to 4,110 B.C. and 4,110 B.C. to 1,950 B.C., and identified as of human origin. Only at the unit II coprolites containing helminth eggs identified as Diphyllobothrium pacificum were found. The presence of this tapeworm, a parasite of the American Sea Lion, in human coprolites, points to a diet which included marine fishes and provides information on the antiquity of infection by Diphyllobothrium pacificum. It is interesting to note that Baer (1969 suggests the presence of this tapeworm in pre-Columbian populations when diagnosing the first human cases in today's population in Peru.Os autores realizaram exame parasitológico de vinte e seis coprólitos encontrados em um sítio arqueológico no norte do Chile, Província de Iquique.O material foi colhido em duas unidades de escavação, I e II (sitio Tiliviche datados respectivamente de 5.900 a.C. a 4.100 a.C. e 4.110 a.C. a 1.950 a.C. e identificados como de origem humana.Na unidade II foram observados ovos de helmintos diagnosticados como de Diphyllobothrium pacificum. Esse achado nos informa sobre a antiguidade da infecção bem como sobre os hábitos alimentares dessas populações, uma vez que a contaminação se da por ingestão de peixes marinhos. E interessante assinalar que Baer (1969, ao descrever pela primeira vez a infecção humana por esse cestódeo em populações atuais do Peru, sugere a sua presença nas populações pré-colombianas.

Spatial and temporal variability of planktonic archaeal abundance in the Humboldt Current System off Chile

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Quiñones, Renato A.; Levipan, Héctor A.; Urrutia, Homero

2009-07-01

The latest advances in the field of microbial ecology have shown that planktonic Archaea are one of the most abundant unicellular microorganisms of the oceans. However, no information is available on the contribution this group makes to the prokaryote assemblages that inhabit the eastern South Pacific Ocean. Here, we describe the relative abundance and vertical distribution of planktonic Archaea off northern and central-southern Chile. Data come from several cruises and a 45-month time series at a station located on the shelf off central-southern Chile. Both the taxonomic composition of the prokaryote community and its relative abundance were determined using quantitative dot blot 16S-rRNA hybridizations. Total Archaea in central-southern Chile made up 6-87% of the prokaryote rRNA in the water column and did not present evidence of any seasonal pattern. Crenarchaea were the most abundant archaeal group at this site and were significantly associated with the ammonium concentration ( r2=0.16, p=0.0003, n=80). Archaeal abundance in the time series was usually greater in the deeper layer (>50 m), with contributions reaching up to ˜90% of the prokaryote rRNA on certain occasions, and decreasing towards the surface. Important increments in the relative abundance of total Archaea were observed on given dates at the surface of the time-series station off central-southern Chile. Off northern Chile, total Archaea normally contributed from ˜10% to 50% of the prokaryote rRNA found between 10 and 1000 m, and were generally important in the mesopelagic realm. Our results indicate that Archaea constitute an important fraction of the prokaryote assemblage in the water column of the Humboldt Current System, especially in the oxygen minimum zone.

Diagenetic changes in Concholepas concholepas shells (Gastropoda, Muricidae in the hyper-arid conditions of Northern Chile – implications for palaeoenvironmental reconstructions

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L. Ortlieb

2009-02-01

Full Text Available Variations in the chemical composition of fossil biogenic carbonates, and in particular of mollusc shells, have been used in a range of palaeoenvironmental reconstructions. It is of primary importance, therefore, to detect and understand the diagenetic processes that may modify the original chemical signature. This microstructural and biogeochemical study focuses on modern and fossil (Holocene and Pleistocene shells of a littoral gastropod of Northern Chile, and on the characterization of mineral component transformations at the nanometric scale and concomitant intracrystalline organic compound modifications. The inner aragonite layer of the shell exhibits more complex deteriorations than the calcite layer. This preliminary study confirms that physical and chemical alterations of various components of mollusc shell biocrystals are complex and might manifest in different ways even within a single individual. The single criterion of determining the mineralogical composition to verify the conservation state of shell samples is insufficient.

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

Water and sediment quality of the Lake Andes and Choteau Creek basins, South Dakota, 1983-2000

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Sando, Steven Kent; Neitzert, Kathleen M.

2003-01-01

The Bureau of Reclamation has proposed construction of the Lake Andes/Wagner Irrigation Demonstration Project to investigate environmental effects of irrigation of glacial till soils substantially derived from marine shales. During 1983-2000, the U.S. Geological Survey collected hydrologic, water-quality, and sediment data in the Lake Andes and Choteau Creek Basins, and on the Missouri River upstream and downstream from Choteau Creek, to provide baseline information in support of the proposed demonstration project. Lake Andes has a drainage area of about 230 mi2 (square miles). Tributaries to Lake Andes are ephemeral. Water-level fluctuations in Lake Andes can be large, and the lake has been completely dry on several occasions. The outlet aqueduct from Lake Andes feeds into Garden Creek, which enters Lake Francis Case just upstream from Fort Randall Dam on the Missouri River. For Lake Andes tributary stations, calcium, magnesium, and sodium are approximately codominant among the cations, and sulfate is the dominant anion. Dissolved-solids concentrations typically range from about 1,000 mg/L (milligrams per liter) to about 1,700 mg/L. Major-ion concentrations for Lake Andes tend to be higher than the tributaries and generally increase downstream in Lake Andes. Proportions of major ions are similar among the different lake units (with the exception of Owens Bay), with calcium, magnesium, and sodium being approximately codominant among cations, and sulfate being the dominant anion. Owens Bay is characterized by a calcium sulfate water type. Dissolved-solids concentrations for Lake Andes typically range from about 1,400 to 2,000 mg/L. Whole-water nitrogen and phosphorus concentrations are similar among the Lake Andes tributaries, with median whole-water nitrogen concentrations ranging from about 1.6 to 2.4 mg/L, and median whole-water phosphorus concentrations ranging from about 0.5 to 0.7 mg/L. Whole-water nitrogen concentrations in Lake Andes are similar among the

The GalileoMobile starts its South American voyage - Astronomy education goes on tour through the Andes Mountains

Science.gov (United States)

2009-10-01

and November 2009, and will cover 5000 kilometres. The voyage will largely take place across the Altiplano, or high plateau, shared by Peru, Bolivia and Chile, which is among the poorest regions in these countries. South America and the Andes Mountains were particularly chosen for the GalileoMobile Project for several reasons. IYA2009 already has a strong presence in the region through national contacts, including three Cornerstone IYA2009 projects: Developing Astronomy Globally, Universe Awareness and the Galileo Teacher Training Programme, which are all official partners of the project. Most people in Peru, Bolivia and Chile speak the same language, Spanish [1], and have a rich astronomical heritage dating back to the pre-Columbian Inca and Tiwanaku civilisations that lived on the Altiplano. The region's high elevation and the quality of its skies for astronomical observations also made it an attractive candidate for the maiden voyage of the GalileoMobile. The journey starts today 5 October 2009 in Antofagasta, Chile, with a free, public inauguration event at 19:00 in the Berta González Square at the Universidad Católica del Norte. The event, which will include observations of the night sky, is organised by ESO in collaboration with Explora II Region and the Astronomy Institute of the University. From Antofagasta the GalileoMobile heads north through La Paz in Bolivia and on into Peru. The return trip to Antofagasta goes via the Panamericana coastal road, and passes near the home of ESO's world-class observatory, the Very Large Telescope at Cerro Paranal. ESO Education and Outreach coordinator in Chile, Laura Ventura, will assist the GalileoMobile team as they greet communities throughout Chile's northern deserts. "The GalileoMobile is a wonderful initiative, and a unique opportunity to reinforce educational activities in the north of Chile and the neighbouring countries. It will promote greater awareness of astronomy and science", says Ventura. "We are looking

Clinical and Demographical Characteristics of Patients with Medication Overuse Headache in Argentina and Chile

DEFF Research Database (Denmark)

Shand, Beatriz; Goicochea, Maria Teresa; Valenzuela, Raul

2015-01-01

population was formed by 240 MOH subjects, 110 from Chile and 130 from Argentina, consecutively attending the local headache centres. In each centre, specifically trained neurologist interviewed and confirmed the diagnosis according to the ICHD-II criteria. A detailed history was collected on an electronic......BACKGROUND: Data on the characteristics of Medication Overuse Headache (MOH) in Latin American (LA) are scarce. Here we report the demographic and clinical features of the MOH patients from Argentina and Chile enrolled in the multinational COMOESTAS project in the period 2008-2010. METHODS: The LA......, where it affects mostly women, in the most active decades of life. Some differences emerge as regards the demographic and clinical characteristics of MOH in this population as compared to Europe or Northern America. What seems more worrying about MOH in Argentina and Chile is that most patients overuse...

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

Altiplano and portions of the Eastern Cordillera, and at approximately 40 under the sub-Andes and westernmost edge of the Beni basin. Unlike previous studies farther south, we do not see an increased crustal thickness beneath the Eastern Cordillera. The CAUGHT station coverage is also ideal for Ambient Noise Tomography (ANT) to investigate the seismic shear wave velocities in the upper crust (<30 km depth). ANT will be used to estimate the depth of basins in the northern Altiplano, and aid in constraining the upper crustal shear wave velocities for improved migration of receiver functions to depth. McQuarrie, N., Barnes, J., and Ehlers, T.A., 2008, Geometric, kinematic and erosional history of the central Andean Plateau (15-17°S), northern Bolivia: Tectonics, v. 27, TC3007, doi:10.1029/2006TC002054.

Issues of affinity: exploring population structure in the Middle and Regional Developments Periods of San Pedro de Atacama, Chile.

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Torres-Rouff, Christina; Knudson, Kelly J; Hubbe, Mark

2013-11-01

The Middle Period (AD 400-1000) in northern Chile's Atacama oases is characterized by an increase in social complexity and regional interaction, much of which was organized around the power and impact of the Tiwanaku polity. Despite the strong cultural influence of Tiwanaku and numerous other groups evident in interactions with Atacameños, the role of immigration into the oases during this period is unclear. While archaeological and bioarchaeological research in the region has shown no evidence that clearly indicates large groups of foreign immigrants, the contemporary increase in interregional exchange networks connecting the oases to other parts of the Andes suggests residential mobility and the possibility that movement of people both into and out of the oases accompanied these foreign influences. Here, we analyze biodistance through cranial non-metric traits in a skeletal sample from prehistoric San Pedro de Atacama to elucidate the extent of foreign influence in the oases and discuss its implications. We analyzed 715 individuals from the Middle Period (AD 400-1000) and later Regional Developments Period (AD 1000-1450), and found greater phenotypic differences between Middle Period cemeteries than among cemeteries in the subsequent period. We argue that this greater diversity extends beyond the relationship between the oases and the renowned Tiwanaku polity and reflects the role of the oases and its different ayllus as a node and way station for the Middle Period's myriad interregional networks. Copyright © 2013 Wiley Periodicals, Inc.

Prediction of extreme floods in the Central Andes by means of Complex Networks

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Boers, Niklas; Bookhagen, Bodo; Barbosa, Henrique; Marwan, Norbert; Kurths, Jürgen; Marengo, Jose

2014-05-01

Based on a non-linear synchronisation measure and complex network theory, we present a novel framework for the prediction of extreme events of spatially embedded, interrelated time series. This method is general in the sense that it can be applied to any type of spatially sampled time series with significant interrelations, ranging from climate observables to biological or stock market data. In this presentation, we apply our method to extreme rainfall in South America and show how this leads to the prediction of more than 60% (90% during El Niño conditions) of extreme rainfall events in the eastern Central Andes of Bolivia and northern Argentina, with only 1% false alarms. From paleoclimatic to decadal time scales, the Central Andes continue to be subject to pronounced changes in climatic conditions. In particular, our and past work shows that frequency as well as magnitudes of extreme rainfall events have increased significantly during past decades, calling for a better understanding of the involved climatic mechanisms. Due to their large spatial extend and occurrence at high elevations, these extreme events often lead to severe floods and landslides with disastrous socioeconomic impacts. They regularly affect tens of thousands of people and produce estimated costs of the order of several hundred million USD. Alongside with the societal value of predicting natural hazards, our study provides insights into the responsible climatic features and suggests interactions between Rossby waves in polar regions and large scale (sub-)tropical moisture transport as a driver of subseasonal variability of the South American monsoon system. Predictable extreme events result from the propagation of extreme rainfall from the region of Buenos Aires towards the Central Andes given characteristic atmospheric conditions. Our results indicate that the role of frontal systems originating from Rossby waves in polar latitudes is much more dominant for controlling extreme rainfall in

The evolution of seabirds in the Humboldt Current: new clues from the Pliocene of Central Chile.

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Martín Chávez Hoffmeister

Full Text Available During the last decade, new Neogene fossil assemblages from South America have revealed important clues about the evolution of seabird faunas in one of the major upwelling systems of the world: the Humboldt Current. However, most of this record comes from arid Northern Chile and Southern Peru and, in consequence, our knowledge of the evolutionary history of seabirds in the temperate transitional zone is negligible. A new Late Pliocene assemblage of fossil birds from the coastal locality of Horcon in Central Chile offers a unique opportunity to fill this gap.Isolated bones of a medium-sized penguin are the most abundant bird remains. Morphological and cladistic analyses reveal that these specimens represent a new species of crested penguin, Eudyptes calauina sp. nov. Eudyptes is a penguin genus that inhabit temperate and subantarctic regions and currently absent in central Chile. Additionally, a partial skeleton of a small species of cormorant and a partial tarsometatarsus of a sooty shearwater have been identified.The Horcon fossils suggest the existence of a mixed avifauna in central Chile during the Pliocene in concordance with the latitudinal thermal gradient. This resembles the current assemblages from the transitional zone, with the presence of species shared with Northern Chile and Southern Peru and a previously unrecorded penguin currently absent from the Humboldt System but present in the Magellanic region. Comparison of Pliocene seabird diversity across the Pacific coast of South America shows that the Horcon avifauna represents a distinctive assemblage linking the living faunas with the Late Miocene ones. A comparison with the fossil record near the Benguela Current (west coast of southern Africa suggests that the thermic gradient could play an important role in the preservation of a higher diversity of cold/temperate seabirds in the Humboldt Current.

Oxygenation variability in Mejillones Bay, off northern Chile, during the last two centuries

NARCIS (Netherlands)

Diaz-Ochoa, J.A.; Pantoja, S.; de Lange, G.J.; Lange, C.B.; Sanchez, G.E.; Acuna, V.R.; Munoz, P.; Vargas, G.

2011-01-01

The Peru Chile Current ecosystem is characterized by high biological productivity and important fisheries. Although this system is likely to be severely affected by climate change, its response to current global warming is still uncertain. In this paper, we analyze 10–166 year-old sediments in two

Protecting the Local Dark-Sky Areas around the International Observatories in Chile.

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Smith, M. G.

2001-12-01

This report covers efforts by IAU Commission 50's new Working Group on Light Pollution to slow or halt the spread of incipient light pollution near the VLT, the Magellan 6.5m telescopes, Gemini South, SOAR, Blanco and many smaller telescopes in Chile. An effort has just begun to protect the ALMA site in Northern Chile from RFI. Such work includes extensive outreach programs to the local population, schools and industry as well as to local, regional and national levels of government in Chile. The group is working internationally with such organizations as the IDA; one member has recently led the production of "The first world atlas of the artificial night-sky brightness". These efforts have resulted in the first national-level environmental legislation covering dark skies as part of a government effort to protect the environment. Chilean manufacturers are now producing competitive, full-cut-off, street lighting designed specifically to comply with the new legislation. The Chilean national tourism agency is supporting "Astronomical Tourism" based on the dark, clear skies of Chile. An international conference on Controlling Light Pollution and RFI will be held in La Serena, Chile on 5-7 March, 2002, backed up by a parallel meeting of Chilean amateur astronomers. Much work remains to be done. Most of this work is supported by funding from the US National Science Foundation through CTIO, and from ESO, OCIW and CONAMA.

Diversification of clearwing butterflies with the rise of the Andes.

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De-Silva, Donna Lisa; Elias, Marianne; Willmott, Keith; Mallet, James; Day, Julia J

2016-01-01

Despite the greatest butterfly diversity on Earth occurring in the Neotropical Andes and Amazonia, there is still keen debate about the origins of this exceptional biota. A densely sampled calibrated phylogeny for a widespread butterfly subtribe, Oleriina (Nymphalidae: Ithomiini) was used to estimate the origin, colonization history and diversification of this species-rich group. Neotropics. Ancestral elevation and biogeographical ranges were reconstructed using data generated from detailed range maps and applying the dispersal-extinction-cladogenesis model using stratified palaeogeographical time slice matrices. The pattern of diversification through time was examined by comparing constant and variable rate models. We also tested the hypothesis that a change in elevation is associated with speciation. The Oleriina likely originated in the Andes in the Early to Middle Miocene and rapidly diversified to include four genera all of which also originated in the Andes. These clades, together with four species groups, experienced varying spatial and temporal patterns of diversification. An overall early burst and decreasing diversification rate is identified, and this pattern is reflected for most subclades. Changes in the palaeogeological landscape, particularly the prolonged uplift of the Andes, had a profound impact on the diversification of the subtribe. The Oleriina mostly remained within the Andes and vicariant speciation resulted in some instances. Dynamic dispersal occurred with the disappearance of geological barriers such as the Acre System and the subtribe exploited newly available habitats. Our results confirm the role of the Andean uplift in the evolution of Neotropical biodiversity.

On geographic barriers and Pleistocene glaciations: Tracing the diversification of the Russet-crowned Warbler (Myiothlypis coronata) along the Andes

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2018-01-01

We studied the phylogeography and plumage variation of the Russet-crowned Warbler (Myiothlypis coronata), from Venezuela to Bolivia, with focus on populations from Ecuador and northern Peru. We analyzed sequences of mitochondrial and nuclear genes, geographic distributions, as well as photographs of specimens deposited at museum collections. Phylogenetic analyses identified three major lineages formed by populations from: Venezuela and Colombia (M. c. regulus), Ecuador and northern Peru (M. elata, M. castaneiceps, M. orientalis, M. c. chapmani), and central Peru and Bolivia (M. c. coronata). We found further population structure within M. c. regulus and M. c. coronata, and population structure and complexity of plumage variation within the Ecuador-northern Peru lineage. Time-calibrated trees estimated that most intraspecific variation originated during the Pleistocene; however, this pattern may not be attributed to an increase in diversification rate during that period. We discuss these results in the context of the importance of geographic-ecological barriers in promoting lineage diversification along the Andes and put forward a preliminary taxonomic proposal for major lineages identified in this study. PMID:29522515

On geographic barriers and Pleistocene glaciations: Tracing the diversification of the Russet-crowned Warbler (Myiothlypis coronata) along the Andes.

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Prieto-Torres, David A; Cuervo, Andrés M; Bonaccorso, Elisa

2018-01-01

We studied the phylogeography and plumage variation of the Russet-crowned Warbler (Myiothlypis coronata), from Venezuela to Bolivia, with focus on populations from Ecuador and northern Peru. We analyzed sequences of mitochondrial and nuclear genes, geographic distributions, as well as photographs of specimens deposited at museum collections. Phylogenetic analyses identified three major lineages formed by populations from: Venezuela and Colombia (M. c. regulus), Ecuador and northern Peru (M. elata, M. castaneiceps, M. orientalis, M. c. chapmani), and central Peru and Bolivia (M. c. coronata). We found further population structure within M. c. regulus and M. c. coronata, and population structure and complexity of plumage variation within the Ecuador-northern Peru lineage. Time-calibrated trees estimated that most intraspecific variation originated during the Pleistocene; however, this pattern may not be attributed to an increase in diversification rate during that period. We discuss these results in the context of the importance of geographic-ecological barriers in promoting lineage diversification along the Andes and put forward a preliminary taxonomic proposal for major lineages identified in this study.

Observations of the Breakdown of Mountain Waves Over the Andes Lidar Observatory at Cerro Pachon on 8/9 July 2012

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Hecht, J. H.; Fritts, D. C.; Wang, L.; Gelinas, L. J.; Rudy, R. J.; Walterscheid, R. L.; Taylor, M. J.; Pautet, P. D.; Smith, S.; Franke, S. J.

2018-01-01

Although mountain waves (MWs) are thought to be a ubiquitous feature of the wintertime southern Andes stratosphere, it was not known whether these waves propagated up to the mesopause region until Smith et al. (2009) confirmed their presence via airglow observations. The new Andes Lidar Observatory at Cerro Pachon in Chile provided the opportunity for a further study of these waves. Since MWs have near-zero phase speed, and zero wind lines often occur in the winter upper mesosphere (80 to 100 km altitude) region due to the reversal of the zonal mean and tidal wind, MW breakdown may routinely occur at these altitudes. Here we report on very high spatial/temporal resolution observations of the initiation of MW breakdown in the mesopause region. Because the waves are nearly stationary, the breakdown process was observed over several hours; a much longer interval than has previously been observed for any gravity wave breakdown. During the breakdown process observations were made of initial horseshoe-shaped vortices, leading to successive vortex rings, as is also commonly seen in Direct Numerical Simulations (DNS) of idealized and multiscale gravity wave breaking. Kelvin-Helmholtz instability (KHI) structures were also observed to form. Comparing the structure of observed KHI with the results of existing DNS allowed an estimate of the turbulent kinematic viscosity. This viscosity was found to be around 25 m2/s, a value larger than the nominal viscosity that is used in models.

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.

Espectro polínico y análisis fisicoquímico de mieles de la Región del Biobío, Chile

OpenAIRE

Navarrete, Carolina; Muñoz-Olivera, Gladys; Wells, Guillermo; Becerra, Julio; Alarcón, Julio; Finot, Víctor L.

2016-01-01

RESUMEN Se analizó el espectro polínico y las características fisicoquímicas de 13 muestras de mieles producidas por Apis mellifera en dos áreas con diferente grado de intervención antrópica en la Región del Biobío, Provincia de Ñuble, Chile: a) Depresión Intermedia y b) zonas precordilleranas de la Cordillera de los Andes. Los datos polínicos y físicoquímicos se sometieron a análisis de componentes principales y la diversidad polínica se calculó con el índice de diversidad de Shannon-Weaver ...

Simulation model of the scallop (Argopecten purpuratus farming in northern Chile: some applications in the decision making process Modelo de simulación para el cultivo del ostión (Argopecten purpuratus en el norte de Chile: aplicaciones para la toma de decisiones

Directory of Open Access Journals (Sweden)

Renato Molina

2012-09-01

Full Text Available Aquaculture farming is a complex system integrating several disciplines, including biology, engineering and economics, all which need to be correctly intertwined to have a profitable and environmentally sustainable activity. During the past recent years, scallop (Argopectenpurpuratus farmers in northern Chile have come to comprehend the hard way that aquaculture producers operate in a complex and dynamic environment where natural and economic factors are in constant change. Thus, to keep a profitable and competitive business in today's world, aquaculture farm managers are in need of relatively easy to use tools for efficient and timely decision making. Harvest size and time, mortality and growth rates, stocking rates, costs and market prices are important variables and parameters to monitor, where decisions with respect to their levels or values have to be made. In this context, non-linear and dynamic quantitative bioeconomic models should become valuable tools, for periodic decision making in the aquaculture business. This paper shows how to emulate Chilean scallop farming using a simulation model that mimics some of the industry's features. The model presented here focuses on a scallop aquaculture center that uses the common technology approach of pearl net and lanterns of the northern region of Chile, and analyses the farming strategies based on harvesting size. Also, these strategies were subject to variations in the parameters in order to identify patterns and asses the sensibility of the model to input values.La acuicultura es un sistema complejo que integra varias disciplinas, incluyendo la biología, ingeniería y economía, las cuales deben ser correctamente entrelazadas para lograr una actividad rentable y ambientalmente sostenible. Durante los últimos anos, los cultivadores del ostión del norte (Argopecten purpuratus en Chile han comprendido de la peor manera, que las actividades de acuicultura operan en un entorno complejo y din

A dynamical analysis of the seismic activity of Villarrica volcano (Chile) during September-October 2000

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Tarraga, Marta [Departamento de Volcanologia. Museo Nacional de Ciencias Naturales, CSIC, Madrid (Spain)], E-mail: martat@mncn.csic.es; Carniel, Roberto [Dipartimento di Georisorse e Territorio, Universita di Udine, Via Cotonificio 114, 33100 Udine (Italy)], E-mail: roberto.carniel@uniud.it; Ortiz, Ramon; Garcia, Alicia [Departamento de Volcanologia. Museo Nacional de Ciencias Naturales, CSIC, Madrid (Spain); Moreno, Hugo [Observatorio Volcanologico de los Andes del Sur (OVDAS), Servicio Nacional de Geologia y Mineria de Chile (SERNAGEOMIN), Temuco, IX Region (Chile)

2008-09-15

Although Villarrica volcano in Chile is one of the most active in the southern Andes, the literature studying its seismic activity is relatively scarce. An interesting problem recently tackled is the possibility for a regional tectonic event to trigger a change in the volcanic activity of this basaltic to basaltic-andesitic volcano, which is in turn reflected in the time evolution of the properly volcanic seismicity, especially in the form of a continuous volcanic tremor. In this work, we conduct a spectral, dynamical and statistical analysis of the tremor recorded during September and October 2000, in order to characterize the anomalous behaviour of the volcano following a tectonic event recorded on 20th September 2000. The observed dynamical transitions are compared with remote sensing and visual observations describing the changes in the eruptive style of the volcano.

A dynamical analysis of the seismic activity of Villarrica volcano (Chile) during September-October 2000

International Nuclear Information System (INIS)

Tarraga, Marta; Carniel, Roberto; Ortiz, Ramon; Garcia, Alicia; Moreno, Hugo

2008-01-01

Although Villarrica volcano in Chile is one of the most active in the southern Andes, the literature studying its seismic activity is relatively scarce. An interesting problem recently tackled is the possibility for a regional tectonic event to trigger a change in the volcanic activity of this basaltic to basaltic-andesitic volcano, which is in turn reflected in the time evolution of the properly volcanic seismicity, especially in the form of a continuous volcanic tremor. In this work, we conduct a spectral, dynamical and statistical analysis of the tremor recorded during September and October 2000, in order to characterize the anomalous behaviour of the volcano following a tectonic event recorded on 20th September 2000. The observed dynamical transitions are compared with remote sensing and visual observations describing the changes in the eruptive style of the volcano

Tourism in Chile | CTIO

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Program PIA Program GO-FAAR Program Other Opportunities Tourism Visits to Tololo Astro tourism in Chile Tourism in Chile Information for travelers Visit Tololo Media Relations News Press Release Publications ‹› You are here CTIO Home » Outreach » Tourism » Tourism in Chile Tourism in Chile Map of

Complex brittle deformation pattern along the Southern Patagonian Andes (Argentina)

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Barberón, Vanesa; Sue, Christian; Ronda, Gonzalo; Ghiglione, Matías

2016-04-01

The Southern Patagonian Andes is located in the southern extreme of the Pacific subduction zone, where the Antartic oceanic plate sinks underneath South America. The history of the area begins with compression during Paleozoic, Jurassic extension associated to the rift and opening of the South Atlantic Ocean, then a sag stage in the Lower Cretaceous followed by a foreland phase as a result of plate tectonics (Ghiglione et al., 2016). The kinematic study is concentrated in the Argentinean foothills, between 46°40' and 48° SL. We measured around 800 fault planes and their striaes with the sense of movement in order to characterize the stress field. The software used to make the stress inversion were Tensor (Delvaux, 2011) and Multiple Inverse Method MIM (Yamaji et al., 2011). The stress field map was built with the results of the MIM. We present new data from 48 sites located in the northern sector of the Southern Patagonian Andes. The measurements were made in several rocks from Paleozoic to Lower Cretaceous, even though most were taken in pyroclastic jurassic rocks from El Quemado Complex. Paleostress tensors obtained are mostly strike-slip, although a 25% is normal and there are a few compresional. The pattern of faults found is complex. In some sites the tensor can be locally linked to satellite images and observations from the field or be related to a major thrust front. There is no clear correlation between the age and/or lithology with the tensor since the youngest rocks measured are Lower Cretaceous. Probably there are several generations of family faults connected to different and recent tectonic phases then the paleostress tensors might correspond to the latest tectonic events.

Genetic diversity of Phytophthora infestans in the Northern Andean region.

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Cárdenas, Martha; Grajales, Alejandro; Sierra, Roberto; Rojas, Alejandro; González-Almario, Adriana; Vargas, Angela; Marín, Mauricio; Fermín, Gustavo; Lagos, Luz E; Grünwald, Niklaus J; Bernal, Adriana; Salazar, Camilo; Restrepo, Silvia

2011-02-09

Phytophthora infestans (Mont.) de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana) and tree tomato (Solanum betaceum), all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a) and one mitochondrial (Cox1) region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a.

Genetic diversity of Phytophthora infestans in the Northern Andean region

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Grünwald Niklaus J

2011-02-01

Full Text Available Abstract Background Phytophthora infestans (Mont. de Bary, the causal agent of potato late blight, is responsible for tremendous crop losses worldwide. Countries in the northern part of the Andes dedicate a large proportion of the highlands to the production of potato, and more recently, solanaceous fruits such as cape gooseberry (Physalis peruviana and tree tomato (Solanum betaceum, all of which are hosts of this oomycete. In the Andean region, P. infestans populations have been well characterized in Ecuador and Peru, but are poorly understood in Colombia and Venezuela. To understand the P. infestans population structure in the Northern part of the Andes, four nuclear regions (ITS, Ras, β-tubulin and Avr3a and one mitochondrial (Cox1 region were analyzed in isolates of P. infestans sampled from different hosts in Colombia and Venezuela. Results Low genetic diversity was found within this sample of P. infestans isolates from crops within several regions of Colombia and Venezuela, revealing the presence of clonal populations of the pathogen in this region. We detected low frequency heterozygotes, and their distribution patterns might be a consequence of a high migration rate among populations with poor effective gene flow. Consistent genetic differentiation exists among isolates from different regions. Conclusions The results here suggest that in the Northern Andean region P. infestans is a clonal population with some within-clone variation. P. infestans populations in Venezuela reflect historic isolation that is being reinforced by a recent self-sufficiency of potato seeds. In summary, the P. infestans population is mainly shaped by migration and probably by the appearance of variants of key effectors such as Avr3a.

Enhancing Graduate Education and Research in Ocean Sciences at the Universidad de Concepcion (UDEC) and in Chile: Cooperation Between UDEC and Woods Hole Oceanographic Institution.

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Farrington, J.; Pantoja, S.

2007-05-01

The Woods Hole Oceanographic Institution, USA (WHOI) and the University of Concepcion, Chile (UDEC) entered into an MOU to enhance graduate education and research in ocean sciences in Chile and enhance research for understanding the Southeastern Pacific Ocean. The MOU was drafted and signed after exchange visits of faculty. The formulation of a five year program of activities included: exchange of faculty for purposes of enhancing research, teaching and advising; visits of Chilean graduate students to WHOI for several months of supplemental study and research in the area of their thesis research; participation of Chilean faculty and graduate students in WHOI faculty led cruises off Chile and Peru (with Peruvian colleagues); a postdoctoral fellowship program for Chilean ocean scientists at WHOI; and the establishment of an Austral Summer Institute of advanced undergraduate and graduate level intensive two to three week courses on diverse topics at the cutting edge of ocean science research co-sponsored by WHOI and UDEC for Chilean and South American students with faculty drawn from WHOI and other U.S. universities with ocean sciences graduate schools and departments, e.g. Scripps Institution of Oceanography, University of Delaware. The program has been evaluated by external review and received excellent comments. The success of the program has been due mainly to: (1) the cooperative attitude and enthusiasm of the faculty colleagues of both Chilean Universities (especially UDEC) and WHOI, students and postdoctoral fellows, and (2) a generous grant from the Fundacion Andes- Chile enabling these activities.

Nueva localidad para Alsodes tumultuosus Veloso, Iturra & Galleguillos, 1979 (Amphibia, Alsodidae en la Cordillera de los Andes, Region de O’Higgins, Chile

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Diego Ramírez Álvarez

2015-06-01

Full Text Available Alsodes tumultuosus Veloso, Iturra & Galleguillos, 1979 es un anfibio endémico de Chile, descrito y hasta hace poco conocido únicamente en su localidad tipo, los arroyos cordilleranos del Sector La Parva, en la región Metropolitana. En este artículo se detalla el hallazgo de una nueva localidad para esta especie, en la región de O’Higgins, aproximadamente a 100 kilómetros al sur de La Parva. Este hallazgo, sugiere la ampliación del rango de distribución de esta especie al cordón cordillerano Andino de la región de O’Higgins, y señala la necesidad de efectuar mayores prospecciones e investigación de la especie, que permitan definir claramente su estado de conservación en Chile.

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

Quantitative Temperature Reconstructions from Holocene and Late Glacial Lake Sediments in the Tropical Andes using Chironomidae (non-biting midges)

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Matthews-Bird, F.; Gosling, W. D.; Brooks, S. J.; Montoya, E.; Coe, A. L.

2014-12-01

Chironomidae (non-biting midges) is a family of two-winged aquatic insects of the order Diptera. They are globally distributed and one of the most diverse families within aquatic ecosystems. The insects are stenotopic, and the rapid turnover of species and their ability to colonise quickly favourable habitats means chironomids are extremely sensitive to environmental change, notably temperature. Through the development of quantitative temperature inference models chironomids have become important palaeoecological tools. Proxies capable of generating independent estimates of past climate are crucial to disentangling climate signals and ecosystem response in the palaeoecological record. This project has developed the first modern environmental calibration data set in order to use chironomids from the Tropical Andes as quantitative climate proxies. Using surface sediments from c. 60 lakes from Bolivia, Peru and Ecuador we have developed an inference model capable of reconstructing temperatures, with a prediction error of 1-2°C, from fossil assemblages. Here we present the first Lateglacial and Holocene chironomid-inferred temperature reconstructions from two sites in the tropical Andes. The first record, from a high elevation (4153 m asl) lake in the Bolivian Andes, shows persistently cool temperatures for the past 15 kyr, punctuated by warm episodes in the early Holocene (9-10 kyr BP). The chironomid-inferred Holocene temperature trends from a lake sediment record on the eastern Andean flank of Ecuador (1248 m asl) spanning the last 5 millennia are synchronous with temperature changes in the NGRIP ice core record. The temperature estimates suggest along the eastern flank of the Andes, at lower latitudes (~1°S), climate closely resemble the well-established fluctuations of the Northern Hemisphere for this time period. Late-glacial climate fluctuations across South America are still disputed with some palaeoecological records suggesting evidence for Younger Dryas

Landscape connectivity among remnant populations of guanaco (Lama guanicoe Müller, 1776) in an arid region of Chile impacted by global change.

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Espinosa, Mara I; Gouin, Nicolas; Squeo, Francisco A; López, David; Bertin, Angéline

2018-01-01

Connectivity between populations plays a key role in the long-term persistence of species in fragmented habitats. This is of particular concern for biodiversity preservation in drylands, since water limited landscapes are typically characterized by little suitable habitat cover, high habitat fragmentation, harsh matrices, and are being rapidly degraded at a global scale. In this study, we modelled landscape connectivity between 11 guanaco Lama guanicoe populations in Chile's arid Norte Chico, a region that supports the last remnant coastal populations of this emblematic herbivore indigenous to South America. We produced a habitat suitability model to derive a regional surface resistance map, and used circuit theory to map functional connectivity, investigate the relative isolation between populations, and identify those that contribute most to the patch connectivity network. Predicted suitable habitat for L. guanicoe represented about 25% of the study region (i.e., 29,173 km 2 ) and was heterogeneously distributed along a continuous stretch along the Andes, and discontinuous patches along the coast. As a result, we found that high connectivity current flows in the mid and high Andes formed a wide, continuous connectivity corridor, enabling connectivity between all high Andean populations. Coastal populations, in contrast, were more isolated. These groups demonstrate no inter-population connectivity between themselves, only with higher altitude populations, and for two of them, animal movement was linked to the effectiveness of wildlife crossings along the Pan-American highway. Our results indicate that functional connectivity is an issue of concern for L. guanicoe in Chile's Norte Chico, implying that future conservation and management plans should emphasize strategies aimed at conserving functional connectivity between coastal and Andean populations, as well as the protection of habitat patches likely to act as stepping stones within the connectivity network.

Chile.

Science.gov (United States)

1992-05-01

The background notes on Chile provide a statistical summary of the population, geography, government, and the economy, and more descriptive text on the history, population, government, economy, defense, and foreign relations. In brief, Chile has 13.3 million Spanish Indian (Mestizos), European, and Indian inhabitants and an annual growth rate of 1.6%. 96% are literate. Infant mortality is 18/1000. 34% of the population are involved in industry and commerce, 30% in services, 19% in agriculture and forestry and fishing, 7% in construction, and 2% in mining. The major city is Santiago. The government, which gained independence in 1810, is a republic with executive, legislative, and judicial branches. There are 12 regions. There are 6 major political parties. Suffrage is universal at 18 years. Gross domestic product (GDP) is $29.2 billion. The annual growth rate is 5% and inflation is 19%. Copper, timber, fish, iron ore, nitrates, precious metals, and molybdenum are its natural resources. Agricultural products are 9% of GDP and include wheat, potatoes, corn, sugar beets, onions, beans, fruits, and livestock. Industry is 21% of GDP and includes mineral refining, metal manufacturing, food and fish processing, paper and wood products, and finished textiles. $8.3 billion is the value of exports and $7 billion of imports. Export markets are in Japan, the US, Germany, Brazil, and the United Kingdom. Chile received $3.5 billion in economic aid between 1949-85, but little in recent years. 83% live in urban centers, principally around Santiago. Congressional representation is made on the basis of elections by a unique binomial majority system. Principal government officials are identified. Chile has a diversified free market economy and is almost self-sufficient in food production. The US is a primary trading partner. 49% of Chile's exports are minerals. Chile maintains diplomatic relations with 70 countries, however, relations are strained with Argentina and Bolivia. Relations

SRTM Perspective of Colored Height and Shaded Relief Laguna Mellquina, Andes Mountains, Argentina

Science.gov (United States)

2001-01-01

This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM)view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters (2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.Three visualization methods were combined to produce this image: shading, color coding of topographic height and a perspective view. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations. The perspective is toward the west, 20 degrees off horizontal with 2X vertical exaggeration. The back (west) edge of the data set forms a false skyline within the Andes Range.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved

Rb-Sr ages and initial 87Sr/86Sr ratios of late paleozoic granitic rocks from northern Chile

International Nuclear Information System (INIS)

Shibata, Ken; Ishihara, Shunso; Ulriksen, C.E.

1984-01-01

Rb-Sr whole-rock isochron ages were determined on three suites of so-called Paleozoic granitic rocks from northern coastal Chile. The granitic rocks from the Valparaiso and Ci Funcho areas are dated as 296.3 +- 5.4 Ma and 262.2 +- 4.6 Ma, respectively, which are in accord with geologically estimated age. The rocks from the Chanaral area is dated as 212.8 +- 8.6 Ma, which is correlated close to the Triassic-Jurassic boundary age. A K-Ar age of 196 +- 6 Ma was obtained on biotite in granite from Esmeralda between Ci Funcho and Chanaral. These age results demonstrate that no Precambrian plutonism occurred in the studied area, and that so-called Paleozoic granitic rocks in the Ci Funcho-Chanaral area are divided into Permian and early Mesozoic in age. Initial 87 Sr/ 86 Sr ratios of the ilmenite-series granitic rocks from the coastal region are 0.70641 (Valparaiso), 0.70635 (Ci Funcho) and 0.70455 (Chanaral). These relatively low ratios deny substantial crustal contribution to the granitoids. The initial ratios of magnetite-series granitoids from porphyry- and manto-type mineralized areas (Chiquicamata, El Salvador and Tocopilla) are as low as 0.70344 to 0.70464. (author)

Redescripción y consideraciones biogeográfcas de dos especies de Scotobius (Coleoptera: Tenebrionidae de ambientes montanos del centro de Argentina y Chile Redescription and biogeographic considerations of two species of Scotobius (Coleoptera: Tenebrionidae from mountain environments of central Argentina and Chile

Directory of Open Access Journals (Sweden)

Violeta A. Silvestro

2012-12-01

Full Text Available El género neotropical Scotobius Germar (Tenebrioninae: Scotobiini comprende 61 especies distribuidas desde el centro de Perú y sur de Brasil hasta el sur de Argentina y Chile. En este trabajo, revisamos dos especies de Scotobius que habitan el oeste de las provincias de San Juan, Mendoza y Neuquén (Argentina y en Chile central, a lo largo de la Cordillera de los Andes y las montañas extra-andinas en Argentina: S. punctatus Eschscholtz, 1831 y S. andrassyi Kaszab, 1969. Se proveen redescripciones utilizando nuevos caracteres morfológicos y se proporcionan fotografías de los adultos y de los pronotos. Se consigna la distribución geográfica, rangos altitudinales y las provincias biogeográficas en las que habitan estas especies. Se utiliza un modelo predictivo de distribución de especies para proponer hipótesis sobre los factores que influencian la distribución espacial y que explicarían la alopatría de ambas especies.The Neotropical genus Scotobius Germar (Tenebrioninae: Scotobiini comprises 61 species distributed from central Peru and southern Brazil to southern Argentine and Chile. In this contribution two species of Scotobius: S. punctatus Eschscholtz, 1831 and S. andrassyi Kaszab, 1969, that inhabit in western San Juan, Mendoza, and Neuquén provinces (Argentina and in central Chile, along the “Cordillera de los Andes” and extra-Andean mountains in Argentina, are revised. Redescriptions using new morphological data and photographs of habitus and pronota are provided. This article informs about the geographic distribution, altitudinal ranges and the biogeographic provinces that these species inhabit. A predictive model of species distribution is presented to propose hypothesis about the factors that influence the space distribution and the allopatry of these two species.

Promoting Dark Sky Protection in Chile: the Gabriel Mistral IDA Dark Sky Sanctuary and Other AURA Initiatives

Science.gov (United States)

Smith, R. Chris; Smith, Malcolm; Pompea, Stephen; Sanhueza, Pedro; AURA-Chile EPO Team

2018-01-01

For over 20 years, AURA has been leading efforts promoting the protection of dark skies in northern Chile. Efforts began in the early 1990s at AURA's Cerro Tololo Inter-American Observatory (CTIO), working in collaboration with other international observatories in Chile including Las Campanas Observatory (LCO) and the European Southern Observatory (ESO). CTIO also partnered with local communities, for example supporting Vicuña's effort to establish the first municipal observatory in Chile. Today we have developed a multifaceted effort of dark sky protection, including proactive government relations at national and local levels, a strong educational and public outreach program, and a program of highlighting international recognition of the dark skies through the IDA Dark Sky Places program. Work on international recognition has included the declaration of the Gabriel Mistral IDA Dark Sky Sanctuary, the first such IDA sanctuary in the world.

Litterfall production under pine plantations in the southern Andes region of Ecuador

Directory of Open Access Journals (Sweden)

Pablo Quichimbo

2016-09-01

Full Text Available Litterfall research is an interesting aspect in environmental studies due to its significance in nutrient cycling specially in regions like the Andes where the interactions between biomass production and its decomposition is poorly understood. This study is focusing in the litterfall biomass production under pine plantations in southern Ecuador. The litterfall production was studied for five months at two-week intervals in three pine forest sites located in the southern Andes region of Ecuador. Monthly litterfall production ranged between 1067-1907 kg ha-1, in comparison with other coniferous stands around the world, this study revealed a higher litterfall production for tropical areas and particularly the highest production under pine plantations in the Andes region. This high litterfall production highlights the upmost importance of this forest component as a potential nutrient reservoir involved in the global nutrient cycling under landscapes dominated by this exotic forest specie in the tropical Andes.

Charles Darwin in the Andes

Science.gov (United States)

Bizzo, Nelio; Bizzo, Luis Eduardo Maestrelli

2006-01-01

Considering geological time as an important epistemological obstacle to the construction of ideas on biological evolution, a study was carried out on the so-called "Darwin Papers". The conclusion was that Charles Darwin's excursion in the Andes during March-April 1835 was a crucial step in this regard. An expedition was carried out in…

Redescripción y consideraciones biogeográficas de dos especies de Scotobius (Coleoptera: Tenebrionidae de ambientes montanos del centro de Argentina y Chile

Directory of Open Access Journals (Sweden)

Violeta A. SILVESTRO

2012-01-01

Full Text Available El género neotropical Scotobius Germar (Tenebrioninae: Scotobiini comprende 61 especies distribuidas desde el centro de Perú y sur de Brasil hasta el sur de Argentina y Chile. En este trabajo, revisamos dos especies de Scotobius que habitan el oeste de las provincias de San Juan, Mendoza y Neuquén (Argentina y en Chile central, a lo largo de la Cordillera de los Andes y las montañas extra-andinas en Argentina: S. punctatus Eschscholtz, 1831 y S. andrassyi Kaszab, 1969. Se proveen redescripciones utilizando nuevos caracteres morfológicos y se proporcionan fotografías de los adultos y de los pronotos. Se consigna la distribución geográfica, rangos altitudinales y las provincias biogeográficas en las que habitan estas especies. Se utiliza un modelo predictivo de distribución de especies para proponer hipótesis sobre los factores que influencian la distribución espacial y que explicarían la alopatría de ambas especies.

SRTM Colored Height and Shaded Relief: Laguna Mellquina, Andes Mountains, Argentina

Science.gov (United States)

2001-01-01

This depiction of an area south of San Martin de Los Andes, Argentina, is the first Shuttle Radar Topography Mission (SRTM) view of the Andes Mountains, the tallest mountain chain in the western hemisphere. This particular site does not include the higher Andes peaks, but it does include steep-sided valleys and other distinctive landforms carved by Pleistocene glaciers. Elevations here range from about 700 to 2,440 meters(2,300 to 8,000 feet). This region is very active tectonically and volcanically, and the landforms provide a record of the changes that have occurred over many thousands of years. Large lakes fill the broad mountain valleys, and the spectacular scenery here makes this area a popular resort destination for Argentinians.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U

DNA from herbarium specimens settles a controversy about origins of the European potato.

Science.gov (United States)

Ames, Mercedes; Spooner, David M

2008-02-01

Landrace potato cultivars are native to two areas in South America: the high Andes from eastern Venezuela to northern Argentina and the lowlands of south-central Chile. Potato first appeared outside of South America in Europe in 1567 and rapidly diffused worldwide. Two competing hypotheses suggested the origin of the "European" potato from the Andes or from lowland Chile, but the Andean origin has been widely accepted over the last 60 years. All modern potato cultivars predominantly have Chilean germplasm, explained as originating from breeding with Chilean landraces subsequent to the late blight epidemics beginning in 1845 in the UK. The Andean origin has been questioned recently through examination of landraces in India and the Canary Islands, but this evidence is inferential. Through a plastid DNA deletion marker from historical herbarium specimens, we report that the Andean potato predominated in the 1700s, but the Chilean potato was introduced into Europe as early as 1811 and became predominant long before the late blight epidemics in the UK. Our results provide the first direct evidence of these events and change the history of introduction of the European potato. They shed new light on the value of past breeding efforts to recreate the European potato from Andean forms and highlight the value of herbarium specimens in investigating origins of crop plants.

Evolutionary persistence in Gunnera and the contribution of southern plant groups to the tropical Andes biodiversity hotspot

Directory of Open Access Journals (Sweden)

Christine D. Bacon

2018-03-01

Full Text Available Several studies have demonstrated the contribution of northern immigrants to the flora of the tropical Andes—the world’s richest and most diverse biodiversity hotspot. However, much less is known about the biogeographic history and diversification of Andean groups with southern origins, although it has been suggested that northern and southern groups have contributed roughly equally to the high Andean (i.e., páramo flora. Here we infer the evolutionary history of the southern hemisphere plant genus Gunnera, a lineage with a rich fossil history and an important ecological role as an early colonising species characteristic of wet, montane environments. Our results show striking contrasts in species diversification, where some species may have persisted for some 90 million years, and whereas others date to less than 2 Ma since origination. The outstanding longevity of the group is likely linked to a high degree of niche conservatism across its highly disjunct range, whereby Gunnera tracks damp and boggy soils in cool habitats. Colonisation of the northern Andes is related to Quaternary climate change, with subsequent rapid diversification appearing to be driven by their ability to take advantage of environmental opportunities. This study demonstrates the composite origin of a mega-diverse biota.

International Uranium Resources Evaluation Project (IUREP) national favourability studies: Bolivia

International Nuclear Information System (INIS)

1977-08-01

Bolivia has an area of 1,098,580 square kilometers. Its capital is La Paz. The western part of the country is dominated by two ranges of the Andes Mountains, the Cordillera Occidental on the vest flank of the high plateau (Altiplano) and the Cordillera Real (or Oriental) on the east flank. The northern Andes average 5,486 meters in elevation; the southern Andes are not as lofty. The Altiplano is 3,658 to A,267 meters high and 129 km. in average width; it is the largest basin of inland drainage in South America and contains the renowned Lake Titicaca on the Peruvian-Bolivian border. The eastern tropical lowlands or pampas (Oriente) comprise about two-thirds of the country, with rain forest in the northern portion. An intermediate zone of valleys and basins lies between the eastern Andes and Oriente. Bolivia differs from other Andean countries, like Chile, Peru and Ecuador, in having large areas of Preeambrian schists, gneisses, migmatites and granites. These crop out in the eastern part of the country. Parts of these rocks contain banded iron formations (i.e., in the Muttin region) and are probably early Precambrian in age. Little systematic exploration for uranium was undertaken in Bolivia until the late 1960's. In 1967, 1968 and 1969 technical assistance was requested from, and provided by, the IAEA. This work led to evaluation of radioactive anomalies in veins of northeast Bolivia and in sandstones in the extreme southern part of the country. Although no uranium reserves are now credited to Bolivia, the geologic possibilities for several kinds of uranium deposits coupled with the relatively limited work done to date suggest that uranium orebodies will be discovered. It is estimated that the potential resources of Bolivia are in the range of 10,000 to 100,000 tonnes uranium

The Sabethines of Northern Andean Coffee-Growing Regions of Colombia.

Science.gov (United States)

Suaza-Vasco, Juan; López-Rubio, Andrés; Galeano, Juan; Uribe, Sandra; Vélez, Iván; Porter, Charles

2015-06-01

Sampling for sabethine mosquitoes occurred intermittently from September 2007 to April 2013 in 17 municipalities, located in 5 departments (divisions) in the northern Andean coffee-growing regions of Colombia. Of the 9 genera within the Sabethini tribe known to occur in the Neotropical region, 6 were encountered including 15 species: Jonhbelkinia ulopus, Limatus durhamii, Sabethes ignotus, Sa. luxodens, Sa. undosus, Shannoniana fluviatilis, Trichoprosopon compressum, Tr. digitatum, Tr. evansae, Tr. pallidiventer s.l., Tr. pallidiventer s.s., Wyeomyia arthrostigma, Wy. oblita, Wy. ulocoma, and Wy. undulata. The species Sa. luxodens and Wy. undulata constitute new records for Colombia. These records broaden the knowledge of this important group that includes some important species related to the arbovirus transmission. Records are from the northern Colombian Andes, a region noted for coffee cultivation and ecotourism.

A measurement of the cosmic microwave background from the high Chilean Andes

Science.gov (United States)

Miller, Amber Dawn

A measurement of the angular spectrum of the Cosmic Microwave Background (CMB) between l = 50 and l = 400 is described. Data were obtained using HEMT radiometers at 30 and 40 GHz with angular resolutions of ≈1 deg and ≈0.7 deg respectively and with SIS based receivers at 144 GHz with angular resolution of ≈0.2 deg. Observations were made from Cerro Toco in the Chilean altiplano at an altitude of 17,000 feet in the Northern Chilean Andes. We find that the angular spectrum rises from l = 50 to a peak at l ≈ 200 and falls off at higher angular scales. A peak in the angular spectrum with amplitude, deltaTl ≈ 85muK is thus located for the first time with a single instrument at l ≈ 200. In addition, we find that the detected anisotropy has the spectrum of the CMB. Cosmological implications of this result are discussed.

Influence of climate variability on anchovy reproductive timing off northern Chile

Science.gov (United States)

Contreras-Reyes, Javier E.; Canales, T. Mariella; Rojas, Pablo M.

2016-12-01

We investigated the relationship between environmental variables and the Gonadosomatic Monthly Mean (GMM) index of anchovy (Engraulis ringens) to understand how the environment affects the dynamics of anchovy reproductive timing. The data examined corresponds to biological information collected from samples of the landings off northern Chile (18°21‧S, 24°00‧S) during the period 1990-2010. We used the Humboldt Current Index (HCI) and the Multivariate ENSO Index (MEI), which combine several physical-oceanographic factors in the Tropical and South Pacific regions. Using the GMM index, we studied the dynamics of anchovy reproductive timing at different intervals of length, specifically females with a length between 11.5 and 14 cm (medium class) and longer than 14 cm (large class). Seasonal Autoregressive Integrated Mobile Average (SARIMA) was used to predict missing observations. The trends of the environment and reproductive indexes were explored via the Breaks For Additive Season and Trend (BFAST) statistical technique and the relationship between these indexes via cross-correlation functions (CCF) analysis. Our results showed that the habitat of anchovy switched from cool to warm condition, which also influenced gonad development. This was revealed by two and three significant changes (breaks) in the trend of the HCI and MEI indexes, and two significant breaks in the GMM of each time series of anchovy females (medium and large). Negative cross-correlation between the MEI index and GMM of medium and large class females was found, indicating that as the environment gets warmer (positive value of MEI) a decrease in the reproductive activity of anchovy can be expected. Correlation between the MEI index and larger females was stronger than with medium females. Additionally, our results indicate that the GMM index of anchovy for both length classes reaches two maximums per year; the first from August to September and the second from December to January. The

A large and unusually colored new snake species of the genus Tantilla (Squamata; Colubridae) from the Peruvian Andes.

Science.gov (United States)

Koch, Claudia; Venegas, Pablo J

2016-01-01

A new colubrid species of the genus Tantilla from the dry forest of the northern Peruvian Andes is described on the basis of two specimens, which exhibit a conspicuous sexual dimorphism. Tantilla tjiasmantoi sp. nov. represents the third species of the genus in Peru. The new species is easily distinguished from its congeners by the combination of scalation characteristics and the unusual transversely-banded color pattern on the dorsum. A detailed description of the skull morphology of the new species is given based on micro-computed tomography images. The habitat of this new species is gravely threatened due to human interventions. Conservation efforts are urgently needed in the inter-Andean valley of the Maranon River.

Cerro Amarillo rhyolites, advanced AFC in the northern SVZ, Chile

International Nuclear Information System (INIS)

Godoy, E; Hildreth, W

2001-01-01

Cerro Amarillo is a Quaternary medium size (500m high, 2 km 2 ) rhyolite dome complex located close to the Chile-Argentina border, reaching a height of 4162 m, between the headwaters of the Rio Colina and the Nieves Negras Pass. It overlies a broad anticline of thick Middle Jurassic pelites (Alvarez et al., 1997). Thiele (1980) includes this complex in his 'Unidad Volcanica Antigua', a Pleistocene composite map unit made up of andesites and trachyandesites. Ramos et al. (1997), while recognizing its rhyolitic character, assigned a Tertiary age to the lava domes, most likely based on the late Pliocene age of silicic dikes outcropping eastward, in Argentina. Both the lack of younger overlying units and freshness of its components, together with preservation of the unconsolidated, easily eroded pyroclastic deposits at its base, suggest, however, that it is not older than Pleistocene (au)

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

Science.gov (United States)

McPhee, James; Mengual, Sebastian; MacDonell, Shelley

2017-04-01

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

Review of Coagulation Technology for Removal of Arsenic: Case of Chile

OpenAIRE

Sancha, Ana María

2006-01-01

Coagulation technology has been used since 1970 in northern Chile for removing arsenic from drinking-water. This experience suggests that coagulation is an effective technology for the removal of arsenic. It is currently possible to reduce arsenic from 400 μg/L to 10 μg/L at a rate of 500 L/sec, assuming pH, oxidizing and coagulation agents are strictly controlled. The Chilean experience with the removal of arsenic demonstrates that the water matrix dictates the selection of the arsenic-remov...

An inventory and estimate of water stored in firn fields, glaciers, debris-covered glaciers, and rock glaciers in the Aconcagua River Basin, Chile

Science.gov (United States)

Janke, Jason R.; Ng, Sam; Bellisario, Antonio

2017-11-01

An inventory of firn fields, glaciers, debris-covered glaciers, and rock glaciers was conducted in the Aconcagua River Basin of the semiarid Andes of central Chile. A total of 916 landforms were identified, of which rock glaciers were the most abundant (669) and occupied the most total area. Glaciers and debris-covered glaciers were less numerous, but were about five times larger in comparison. The total area occupied by glaciers and debris-covered glaciers was roughly equivalent to the total area of rock glaciers. Debris-covered glaciers and rock glaciers were subcategorized into six ice-content classes based on interpretation of surface morphology with high-resolution satellite imagery. Over 50% of rock glaciers fell within a transitional stage; 85% of debris-covered glaciers were either fully covered or buried. Most landforms occupied elevations between 3500 and 4500 m. Glaciers and firn occurred at higher elevations compared to rock glaciers and debris-covered glaciers. Rock glaciers had a greater frequency in the northern part of the study area where arid climate conditions exist. Firn and glaciers were oriented south, debris-covered glaciers west, and rock glaciers southwest. An analysis of water contribution of each landform in the upper Andes of the Aconcagua River Basin was conducted using formulas that associate the size of the landforms to estimates of water stored. Minimum and maximum water storage was calculated based on a range of debris to ice content ratios for debris-covered glaciers and rock glaciers. In the Aconcagua River Basin, rock glaciers accounted for 48 to 64% of the water stored within the landforms analyzed; glaciers accounted for 15 to 25%; debris-covered glaciers were estimated at 15 to 19%; firn fields contained only about 5 to 8% of the water stored. Expansion of agriculture, prolonged drought, and removal of ice-rich landforms for mining have put additional pressure on already scarce water resources. To develop long

Glacier monitoring and glacier-climate interactions in the tropical Andes: A review

Science.gov (United States)

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

2017-08-01

In this review, we summarized the evolution of glacier monitoring in the tropical Andes during the last few decades, particularly after the development of remote sensing and photogrammetry. Advantages and limitations of glacier mapping, applied so far, in Venezuela, Colombia, Ecuador, Peru and Bolivia are discussed in detail. Glacier parameters such as the equilibrium line altitude, snowline and mass balance were given special attention in understanding the complex cryosphere-climate interactions, particularly using remote sensing techniques. Glaciers in the inner and the outer tropics were considered separately based on the precipitation and temperature conditions within a new framework. The applicability of various methods to use glacier records to understand and reconstruct the tropical Andean climate between the Last Glacial Maximum (11,700 years ago) and the present is also explored in this paper. Results from various studies published recently were analyzed and we tried to understand the differences in the magnitudes of glacier responses towards the climatic perturbations in the inner tropics and the outer tropics. Inner tropical glaciers, particularly those in Venezuela and Colombia near the January Intertropical Convergence Zone (ITCZ), are more vulnerable to increase in temperature. Surface energy balance experiments show that outer tropical glaciers respond to precipitation variability very rapidly in comparison with the temperature variability, particularly when moving towards the subtropics. We also analyzed the gradients in glacier response to climate change from the Pacific coast towards the Amazon Basin as well as with the elevation. Based on the current trends synthesised from recent studies, it is hypothesized that the glaciers in the inner tropics and the southern wet outer tropics will disappear first as a response to global warming whereas glaciers in the northern wet outer tropics and dry outer tropics show resistance to warming trends due to

External and gastrointestinal parasites of the rufous-collared sparrow Zonotrichia capensis (Passeriformes, Emberizidae in Chile

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Sebastián Llanos-Soto

Full Text Available Abstract A total of 277 rufous-collared sparrows, Zonotrichia capensis Müller, 1776 (Emberizidae, were examined for external parasites. The birds were captured using mist nets in seven locations in northern and central Chile. Additionally, seven carcasses from central Chile (the Biobío region were necropsied to evaluate the presence of endoparasite infection. Ectoparasites were found on 35.8% (99/277 of the examined birds and they were represented by the following arthropods: feather mites Amerodectes zonotrichiae Mironov and González-Acuña, 2014 (Analgoidea: Proctophyllodidae, Proctophyllodes polyxenus Atyeo and Braasch, 1966 (Analgoidea: Proctophyllodidae, and Trouessartia capensis Berla, 1959 (Analgoidea: Trouessartiidae; a louse Philopterus sp. (Phthiraptera: Ischnocera; and ticks Amblyomma tigrinum Koch, 1844 (Acari: Ixodidae and Ixodes auritulus Neumann, 1904 (Acari: Ixodidae. Two of the seven necropsied carcasses were infected with the acanthocephalan Mediorhynchus papillosus Van Cleave, 1916 (Gigantorhynchida: Gigantorhynchidae. To our knowledge, this study reports P. polyxenus, Philopterus sp., A. tigrinum, and M. papillosus for the first time for Z. capensis and expands the distributional range for T. capensis to Chile.

Serological Evidence of Hantavirus Infection in Apparently Healthy People from Rural and Slum Communities in Southern Chile

Directory of Open Access Journals (Sweden)

Claudia Muñoz-Zanzi

2015-04-01

Full Text Available Hantavirus disease in America has been recognizable because of its rapid progression in clinical cases, occurrence in previously healthy young adults, and high case fatality rate. Hantavirus disease has been proposed now to define the diversity of clinical manifestations. Since 1995, a total of 902 cases of hantavirus pulmonary syndrome have been reported in Chile, caused by Andes virus (ANDV, with overall fatality of 32%. This report describes the sero-epidemiology of hantavirus in apparently healthy people in rural and urban slum communities from southern Chile. Ten of 934 samples yielded a positive result resulting in a seroprevalence of 1.07% (95% confidence intervals: 0.05%–2.0%. A higher proportion of positive samples was found among individuals from rural villages (1.3% and slums (1.5% compared with farms (0.5%. Seropositivity was associated with age (p = 0.011, low education level (p = 0.006 and occupations linked to the household (homemaker, retired, or student (p = 0.016. No evidence of infection was found in 38 sigmodontinae rodents trapped in the peri-domestic environment. Our findings highlight that exposure risk was associated with less documented risk factors, such as women in slum and rural villages, and the occurrence of infection that may have presented as flu-like illness that did not require medical attention or was misdiagnosed.

Climatic zoning of chia (Salvia hispanica L. in Chile using a species distribution model

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Daniela Cortés

2017-12-01

Full Text Available Salvia hispanica L., known as chia, is a plant species originally from tropical and subtropical Mesoamerica. It is economically important because its seeds produce omega-3, thus its demand has increased in Chile and internationally. As there is no commercial production in Chile, we investigated the places in the country where this species could be cultivated in order to satisfy at the least the national demand. The aim of the study was to quantify the main climatic requirements of chia and to produce a climatic aptitude map for chia cultivation in Chile. The methodology was based on the Maxent species distribution model. We used 78 georeferenced data points where chia is grown throughout the world, mostly from the GBIF database, along with raster climatic layers from the Worldclim project. We estimated the performance curves of annual precipitation and temperature along with their respective optimal and critical values, in analogy with the Ecocrop method. The maps used two scenarios for crops in different conditions, with and without irrigation. The results indicated that the intermediate depression and coastal edge of mainly the Arica y Parinacota, Tarapacá, Antofagasta and Atacama regions have optimum conditions for irrigated crops, but it would be impossible in rainfed conditions. We conclude that chia’s cultivation niche is reduced due to its tropical climate requirements; however, it can be cultivated under irrigation in northern Chile.

Climatic zoning of chia (Salvia hispanica L.) in Chile using a species distribution model

International Nuclear Information System (INIS)

Cortés, D.; Silva, H.; Baginsky, C.; Morales, L.

2017-01-01

Salvia hispanica L., known as chia, is a plant species originally from tropical and subtropical Mesoamerica. It is economically important because its seeds produce omega-3, thus its demand has increased in Chile and internationally. As there is no commercial production in Chile, we investigated the places in the country where this species could be cultivated in order to satisfy at the least the national demand. The aim of the study was to quantify the main climatic requirements of chia and to produce a climatic aptitude map for chia cultivation in Chile. The methodology was based on the Maxent species distribution model. We used 78 georeferenced data points where chia is grown throughout the world, mostly from the GBIF database, along with raster climatic layers from the Worldclim project. We estimated the performance curves of annual precipitation and temperature along with their respective optimal and critical values, in analogy with the Ecocrop method. The maps used two scenarios for crops in different conditions, with and without irrigation. The results indicated that the intermediate depression and coastal edge of mainly the Arica y Parinacota, Tarapacá, Antofagasta and Atacama regions have optimum conditions for irrigated crops, but it would be impossible in rainfed conditions. We conclude that chia’s cultivation niche is reduced due to its tropical climate requirements; however, it can be cultivated under irrigation in northern Chile.

Climatic zoning of chia (Salvia hispanica L.) in Chile using a species distribution model

Energy Technology Data Exchange (ETDEWEB)

Cortés, D.; Silva, H.; Baginsky, C.; Morales, L.

2017-07-01

Salvia hispanica L., known as chia, is a plant species originally from tropical and subtropical Mesoamerica. It is economically important because its seeds produce omega-3, thus its demand has increased in Chile and internationally. As there is no commercial production in Chile, we investigated the places in the country where this species could be cultivated in order to satisfy at the least the national demand. The aim of the study was to quantify the main climatic requirements of chia and to produce a climatic aptitude map for chia cultivation in Chile. The methodology was based on the Maxent species distribution model. We used 78 georeferenced data points where chia is grown throughout the world, mostly from the GBIF database, along with raster climatic layers from the Worldclim project. We estimated the performance curves of annual precipitation and temperature along with their respective optimal and critical values, in analogy with the Ecocrop method. The maps used two scenarios for crops in different conditions, with and without irrigation. The results indicated that the intermediate depression and coastal edge of mainly the Arica y Parinacota, Tarapacá, Antofagasta and Atacama regions have optimum conditions for irrigated crops, but it would be impossible in rainfed conditions. We conclude that chia’s cultivation niche is reduced due to its tropical climate requirements; however, it can be cultivated under irrigation in northern Chile.

The Maritime Cultural Landscape of Northern Patagonia

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Lira, Nicolás

2017-12-01

This article is a contribution to the study of the indigenous navigation and its boats in the region of northern Patagonia. This article also aims to contribute to the understanding of indigenous navigation practices and technologies and their origins from prehistoric times to the mid-twentieth century. It presents and discusses the concept of Westerdahl's Maritime Cultural Landscape in relation to other landscape concepts. This model is applied to northern Patagonia in order to discuss if it is possible to speak of a true maritime culture in the region. For this purpose, archaeological, historical and ethnographic data are presented in an integrative and innovative methodology for the discipline. Finally, the Maritime Cultural Landscape model will allow the integration of aquatic and terrestrial landscapes as routes traveled by native inhabitants of northern Patagonia and southern Chile, and propose an important and diversified maritime, river and lake tradition.

Exploring pain in the Andes--learning from the Quichua (Inca) people experience.

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Incayawar, Mario; Saucier, Jean-François

2015-05-01

There is a mounting recognition that culture profoundly shapes human pain experience. The 28 million indigenous people of the Andes in South America, mainly the Quichua (Inca) people, share a distinctive culture. However, little is known about their pain experience and suffering. The aim of the present study was to explore how Quichua adults perceive, describe, and cope with the pain. An exploratory qualitative/descriptive study was conducted with a convenience sample of 40 Quichua adults, including 15 women and 25 men, in the Northern Highlands of Ecuador. Data were collected through structured interviews of approximately 3 h, using a Quichua questionnaire called "The Nature of Pain" [Nanay Jahua Tapuicuna]. The interviews covered the notions of causation of pain, vulnerability to pain, responses to pain, aggravating factors, frequent locations of pain, types of pain, duration, characteristics of pain, control of pain, pathways to care, and preventive measures of pain. Basic descriptive analyses were performed. The Quichuas' pain experience is complex and their strategies to cope with it are sophisticated. According to the Quichuas, emotions, life events, co-morbid conditions, and spirits, among others factors play an important role in the origin, diagnosis, and treatment of pain. They strongly embrace biomedicine and physicians as well as Quichua traditional medicine and traditional healers. Family members and neighbors are also valuable sources of health care and pain control. The pathway to pain care that the Quichua people prefer is inclusive and pluralistic. The knowledge of the Quichua ethnographic "emic" details of their belief system and coping strategies to control pain are clinically useful not only for the health professional working in the Andes, some Quichua cultural characteristics related to pain could be useful to the culturally competent health practitioner who is making efforts to provide high-quality medical care in rural and multicultural

Common catabolic enzyme patterns in a microplankton community of the Humboldt Current System off northern and central-south Chile: Malate dehydrogenase activity as an index of water-column metabolism in an oxygen minimum zone

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González, R. R.; Quiñones, R. A.

2009-07-01

An extensive subsurface oxygen minimum zone off northern and central-south Chile, associated with the Peru-Chile undercurrent, has important effects on the metabolism of the organisms inhabiting therein. Planktonic species deal with the hypoxic and anoxic environments by relying on biochemical as well as physiological processes related to their anaerobic metabolisms. Here we characterize, for the first time, the potential enzymatic activities involved in the aerobic and anaerobic energy production pathways of microplanktonic organisms (oxygen concentration and microplanktonic biomass in the oxygen minimum zone and adjacent areas of the Humboldt Current System water column. Our results demonstrate significant potential enzymatic activity of catabolic pathways in the oxygen minimum zone. Malate dehydrogenase had the highest oxidizing activity of nicotinamide adenine dinucleotide (reduced form) in the batch of catabolic enzymatic activities assayed, including potential pyruvate oxidoreductases activity, the electron transport system, and dissimilatory nitrate reductase. Malate dehydrogenase correlated significantly with almost all the enzymes analyzed within and above the oxygen minimum zone, and also with the oxygen concentration and microplankton biomass in the water column of the Humboldt Current System, especially in the oxygen minimum zone off Iquique. These results suggest a possible specific pattern for the catabolic activity of the microplanktonic realm associated with the oxygen minimum zone spread along the Humboldt Current System off Chile. We hypothesize that malate dehydrogenase activity could be an appropriate indicator of microplankton catabolism in the oxygen minimum zone and adjacent areas.

Primer "Entrenamiento en Metodologías de Investigación Clínica en Chile" (EMIC-Chile: Fundamentos psicoeducativos First "Training in Clinical Research Methodologies in Chile" (EMIC-Chile: Psychoeducational foundations

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B. Cabieses

2010-12-01

Full Text Available EMIC-Chile ("Entrenamiento en Metodologías para la Investigación Clínica en Chile" es un proyecto académico desarrollado durante el año 2008 en Chile para entrenar a profesionales de la salud y disciplinas afines en metodología de investigación clínica, con el objetivo de aumentar la calidad de los proyectos de investigación con fines concursables en nuestro país. El propósito de este artículo es dar a conocer el programa y sus fundamentos teóricos de enseñanza-aprendizaje, que estuvieron en la base de la estructura, metodología, evaluación y sistematización del conocimiento entregado. Para ello, primero se describe el programa, la metodología, la evaluación y el seguimiento. Posteriormente se detallan los aspectos psicoeducativos considerados, con especial énfasis en el aprendizaje social y la educación de adultos. Finalmente, se discute en torno a las posibles consideraciones de este programa para futuras intervenciones educativas en investigación en salud en Chile. Se espera que esta experiencia y sus fundamentos educativos sirvan de motor para futuras iniciativas en el área, a favor de la investigación en salud en Chile.EMIC-Chile ("Entrenamiento en Metodologías para la Investigación Clínica en Chile" is an academic project developed in Chile during 2008 to train health professionals in clinical research. The purpose of this initiative was to improve the quality of research projects that are submitted to apply for public funding. The aim of this article is to describe the psycho-educative theories that supported this training program, its structure, methods and evaluation. Firstly, the program is described in detail. Secondly, psycho-educative theories are described, with special emphasis of social learning theory and education for adults. Finally, implications of EMIC-Chile are stated, in order to improve future research training experiences in Chile. It is expected that this article enhance other research experts

Estimation of the heat/Na flux using lidar data recorded at ALO, Cerro Pachon, Chile

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Vargas, F.; Gardner, C. S.; Liu, A. Z.; Swenson, G. R.

2013-12-01

In this poster, lidar nigh-time data are used to estimate the vertical fluxes of heat and Na at the mesopause region due to dissipating gravity waves presenting periods from 5 min to 8 h, and vertical wavelengths > 2 km. About 60 hours of good quality data were recorded near the equinox during two observation campaigns held in Mar, 2012 and Apr, 2013 at the Andes Lidar Observatory (30.3S,70.7W). These first measurements of the heat/Na flux in the southern hemisphere will be discussed and compared with those from the northern hemisphere stations obtained at the Starfire Optical Range, NM, and Maui, HW.

New ICT in the Peruvian Andes: Theoretical Foundation and Bibliographical Balance

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Mario Sánchez-Dávila

2016-04-01

Full Text Available On the one hand, this paper explains the theoretical foundations on which this proposal for digital anthropology in the Peruvian Andes is based (on the origins of digital anthropology, discussions on oral and written technology, and theories of digital technology as social practice. And, on the other hand, this paper presents a bibliographical balance of the studies on the new ICT in the Peruvian Andes (on identity expression, productive development and formal education in the Andean world.

Influence of Biological Factors on Connectivity Patterns for Concholepas concholepas (loco) in Chile.

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Garavelli, Lysel; Colas, François; Verley, Philippe; Kaplan, David Michael; Yannicelli, Beatriz; Lett, Christophe

2016-01-01

In marine benthic ecosystems, larval connectivity is a major process influencing the maintenance and distribution of invertebrate populations. Larval connectivity is a complex process to study as it is determined by several interacting factors. Here we use an individual-based, biophysical model, to disentangle the effects of such factors, namely larval vertical migration, larval growth, larval mortality, adults fecundity, and habitat availability, for the marine gastropod Concholepas concholepas (loco) in Chile. Lower transport success and higher dispersal distances are observed including larval vertical migration in the model. We find an overall decrease in larval transport success to settlement areas from northern to southern Chile. This spatial gradient results from the combination of current direction and intensity, seawater temperature, and available habitat. From our simulated connectivity patterns we then identify subpopulations of loco along the Chilean coast, which could serve as a basis for spatial management of this resource in the future.

Unveiling current Guanaco distribution in chile based upon niche structure of phylogeographic lineages: Andean puna to subpolar forests.

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González, Benito A; Samaniego, Horacio; Marín, Juan Carlos; Estades, Cristián F

2013-01-01

Niche description and differentiation at broad geographic scales have been recent major topics in ecology and evolution. Describing the environmental niche structure of sister taxa with known evolutionary trajectories stands out as a useful exercise in understanding niche requirements. Here we model the environmental niche structure and distribution of the recently resolved phylogeography of guanaco (Lama guanicoe) lineages on the western slope of the southern Andes. Using a maximum entropy framework, field data, and information on climate, topography, human density, and vegetation cover, we identify differences between the two subspecies (L.g.cacsilensis, L.g.guanicoe) and their intermediate-hybrid lineage, that most likely determine the distribution of this species. While aridity seems to be a major factor influencing the distribution at the species-level (annual precipitation ecological and/or evolutionary processes are shaping the niche of guanacos in Chile, producing discrepancies when comparing range distribution at the species-level (81,756 km(2)) with lineages-level (65,321 km(2)). The subspecies-specific description of niche structure is provided here based upon detailed spatial distribution of the lineages of guanacos in Chile. Such description provides a scientific tool to further develop large scale plans for habitat conservation and preservation of intraspecific genetic variability for this far ranging South American camelid, which inhabits a diversity of ecoregion types from Andean puna to subpolar forests.

Total arsenic, lead, and cadmium levels in vegetables cultivated at the Andean villages of northern Chile.

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Queirolo, F; Stegen, S; Restovic, M; Paz, M; Ostapczuk, P; Schwuger, M J; Muñoz, L

2000-06-08

Various vegetables (broad beans, corn, potato, alfalfa and onion) were sampled in northern Chile, Antofagasta Region. They are the basis of human nutrition in this region and of great relevance to human health. This region is characterized by volcanic events (eruptions, thermal springs, etc.). Most of the vegetables cultivated in this area enter the local markets for a population of approximately 4000 people, whose ancestors were mainly atacameños and quechuas (local indigenous people). The cadmium and lead in these foods was determined by differential pulse anodic stripping voltammetry (DPASV). Results indicate that the highest concentration of Pb and Cd are in the potato skin, while the edible part of the potatoes contained a lower concentration of these metals. The INAA analyses of As in the vegetables from Socaire and Talabre, two towns located close to active volcanoes (e.g. Lascar), show a very high As content: 1850 microg/kg in corn (Socaire) and 860 microg/kg in potatoes (+ skin) (Talabre). These values exceed the National Standard for arsenic (500 microg/kg) by approximately 400% and 180%, respectively. In general, the data show a concentration of Pb greater than Cd with the potential for some vegetables to accumulate heavy metals, The values, expressed in fresh weight, vary from 0.2 to 40 microg/g for Cd and from 0.6 to 94 microg/g for Pb. These concentration intervals, except that of arsenic, are within the recommended standards in the Food Sanitary Regulation (Decree 977), which, expressed as fresh weight, must be equal to or smaller than 500 microg/kg for Pb. There is no legal standard for Cd.

Environmental evidence of fossil fuel pollution in Laguna Chica de San Pedro lake sediments (Central Chile)

International Nuclear Information System (INIS)

Chirinos, L.; Rose, N.L.; Urrutia, R.; Munoz, P.; Torrejon, F.; Torres, L.; Cruces, F.; Araneda, A.; Zaror, C.

2006-01-01

This paper describes lake sediment spheroidal carbonaceous particle (SCP) profiles from Laguna Chica San Pedro, located in the Biobio Region, Chile (36 o 51' S, 73 o 05' W). The earliest presence of SCPs was found at 16 cm depth, corresponding to the 1915-1937 period, at the very onset of industrial activities in the study area. No SCPs were found at lower depths. SCP concentrations in Laguna Chica San Pedro lake sediments were directly related to local industrial activities. Moreover, no SCPs were found in Galletue lake (38 o 41' S, 71 o 17.5' W), a pristine high mountain water body used here as a reference site, suggesting that contribution from long distance atmospheric transport could be neglected, unlike published data from remote Northern Hemisphere lakes. These results are the first SCP sediment profiles from Chile, showing a direct relationship with fossil fuel consumption in the region. Cores were dated using the 21 Pb technique. - The lake sediment record of SCPs shows the record of fossil-fuel derived pollution in Central Chile

Environmental evidence of fossil fuel pollution in Laguna Chica de San Pedro lake sediments (Central Chile)

Energy Technology Data Exchange (ETDEWEB)

Chirinos, L. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile)]. E-mail: lchirin@pucp.edu.pe; Rose, N.L. [Environmental Change Research Centre, University College London, 26 Bedford Way, London WG1HOAP (United Kingdom); Urrutia, R. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Munoz, P. [Departamento de Biologia Marina, Universidad Catolica del Norte, Larrondo 1281, Coquimbo (Chile); Torrejon, F. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Torres, L. [Departamento de Botanica, Universidad de Concepcion, Concepcion (Chile); Cruces, F. [Departamento de Botanica, Universidad de Concepcion, Concepcion (Chile); Araneda, A. [Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepcion, PO Box 160-C, Concepcion (Chile); Zaror, C. [Facultad de Ingenieria Quimica, Universidad de Concepcion, Concepcion (Chile)

2006-05-15

This paper describes lake sediment spheroidal carbonaceous particle (SCP) profiles from Laguna Chica San Pedro, located in the Biobio Region, Chile (36{sup o} 51' S, 73{sup o} 05' W). The earliest presence of SCPs was found at 16 cm depth, corresponding to the 1915-1937 period, at the very onset of industrial activities in the study area. No SCPs were found at lower depths. SCP concentrations in Laguna Chica San Pedro lake sediments were directly related to local industrial activities. Moreover, no SCPs were found in Galletue lake (38{sup o} 41' S, 71{sup o} 17.5' W), a pristine high mountain water body used here as a reference site, suggesting that contribution from long distance atmospheric transport could be neglected, unlike published data from remote Northern Hemisphere lakes. These results are the first SCP sediment profiles from Chile, showing a direct relationship with fossil fuel consumption in the region. Cores were dated using the {sup 21}Pb technique. - The lake sediment record of SCPs shows the record of fossil-fuel derived pollution in Central Chile.

A millennium of metallurgy recorded by lake sediments from Morococha, Peruvian Andes.

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Cooke, Colin A; Abbott, Mark B; Wolfe, Alexander P; Kittleson, John L

2007-05-15

To date, information concerning pre-Colonial metallurgy in South America has largely been limited to the archaeological record of artifacts. Here, we reconstruct a millennium of smelting activity in the Peruvian Andes using the lake-sediment stratigraphy of atmospherically derived metals (Pb, Zn, Cu, Ag, Sb, Bi, and Ti) and lead isotopic ratios (206Pb/ 207Pb) associated with smelting from the Morococha mining region in the central Peruvian Andes. The earliest evidence for metallurgy occurs ca. 1000 A.D., coinciding with the fall of the Wari Empire and decentralization of local populations. Smelting during this interval appears to have been aimed at copper and copper alloys, because of large increases in Zn and Cu relative to Pb. A subsequent switch to silver metallurgy under Inca control (ca. 1450 to conquest, 1533 A.D.) is indicated by increases in Pb, Sb, and Bi, a conclusion supported by further increases of these metals during Colonial mining, which targeted silver extraction. Rapid development of the central Andes during the 20th century raised metal burdens by an order of magnitude above previous levels. Our results represent the first evidence for pre-Colonial smelting in the central Peruvian Andes, and corroborate the sensitivity of lake sediments to pre-Colonial metallurgical activity suggested by earlier findings from Bolivia.

Hydrogeology and sustainable future groundwater abstraction from the Agua Verde aquifer in the Atacama Desert, northern Chile

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Urrutia, Javier; Jódar, Jorge; Medina, Agustín; Herrera, Christian; Chong, Guillermo; Urqueta, Harry; Luque, José A.

2018-03-01

The hyper-arid conditions prevailing in Agua Verde aquifer in northern Chile make this system the most important water source for nearby towns and mining industries. Due to the growing demand for water in this region, recharge is investigated along with the impact of intense pumping activity in this aquifer. A conceptual model of the hydrogeological system is developed and implemented into a two-dimensional groundwater-flow numerical model. To assess the impact of climate change and groundwater extraction, several scenarios are simulated considering variations in both aquifer recharge and withdrawals. The estimated average groundwater lateral recharge from Precordillera (pre-mountain range) is about 4,482 m3/day. The scenarios that consider an increase of water withdrawal show a non-sustainable groundwater consumption leading to an over-exploitation of the resource, because the outflows surpasses inflows, causing storage depletion. The greater the depletion, the larger the impact of recharge reduction caused by the considered future climate change. This result indicates that the combined effects of such factors may have a severe impact on groundwater availability as found in other groundwater-dependent regions located in arid environments. Furthermore, the scenarios that consider a reduction of the extraction flow rate show that it may be possible to partially alleviate the damage already caused to the aquifer by the continuous extractions since 1974, and it can partially counteract climate change impacts on future groundwater availability caused by a decrease in precipitation (and so in recharge), if the desalination plant in Taltal increases its capacity.

Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes.

Science.gov (United States)

Herrera, Christian; Custodio, Emilio; Chong, Guillermo; Lambán, Luis Javier; Riquelme, Rodrigo; Wilke, Hans; Jódar, Jorge; Urrutia, Javier; Urqueta, Harry; Sarmiento, Alvaro; Gamboa, Carolina; Lictevout, Elisabeth

2016-01-15

Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water-rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ(18)O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano. Copyright © 2015 Elsevier B.V. All rights reserved.

Tapetes microbianos del Salar de Llamará, norte de Chile Microbial mats from the Llamará salt flat, northern Chile

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CECILIA DEMERGASSO

2003-09-01

incluyendo cocos y bacilos no identificados. En todos los tapetes muestreados en el Salar se encontraron bacterias reductoras de sulfato.Stratified photosynthetic microbial mats are described from the Salar de Llamará, a salt flat basin located in the Atacama desert of northern Chile. Microscopic and spectrophotometric techniques were used. The thickness of the photic zone of these communities spans 8 to 30 mm. This is probably due to the grain size and mineralogical composition of associated sediments. Three different types of mats were recognized. A first one was characterized by a green pigmented layer; a second with orange and green coloured layers, and the third with orange and green layers and an additional purple layer. At one sampling site, no pigmented layers were present. Sediments underlying the mats were white, but in one site, black coloured sediments were observed; this dark colour is probably the result of iron sulphide precipitation. Predominant microorganisms in the orange pigmented layers were diatoms and unicellular cyanobacteria, mainly from the Cyanothece and Synechococcus groups. Filamentous cyanobacteria Microleus sp. and Oscillatoria sp. were the most abundant in the green layer. When interstitial brines reached salinities between 12 and 33 %, no diatoms were observed, and the coccoidal cyanobacteria from the Synechococcus, Cyanothece and Gloeocapsa groups and genus Gloeobacter predominated over filamentous Cyanobacteria in the green layer. The purple layer was built primarily of anoxygenic phototrophic bacteria similar to cells of the genera Chromatium and Thiocapsa. Absorption spectra revealed that chlorophyll a is the most abundant pigment in most of analyzed samples. Integrated values of chlorophyll a and bacteriochlorophyll a reached values of up to 230 and 144 mg m-2 along all of the pigmented zone, respectively. Abundant non-photosynthetic microorganisms were found in the mats, including unidentified cocci and bacilli. Sulphate reducing

Unraveling the diversification history of grasshoppers belonging to the “Trimerotropis pallidipennis” (Oedipodinae: Acrididae species group: a hotspot of biodiversity in the Central Andes

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Noelia Verónica Guzmán

2017-09-01

Full Text Available The Andean Mountain range has been recognized as one of the biodiversity hotspots of the world. The proposed mechanisms for such species diversification, among others, are due to the elevation processes occurring during the Miocene and the intensive glacial action during the Pleistocene. In this study we investigated the diversification history of the grasshopper Trimerotropis pallidipennis species complex which shows a particularly wide latitudinal and altitudinal distribution range across the northern, central and southern Andes in South America. Many genetic lineages of this complex have been so far discovered, making it an excellent model to investigate the role of the central Andes Mountains together with climatic fluctuations as drivers of speciation. Phylogenetics, biogeographic and molecular clock analyses using a multi-locus dataset revealed that in Peru there are at least two, and possibly four genetic lineages. Two different stocks originated from a common ancestor from North/Central America—would have dispersed toward southern latitudes favored by the closure of the Panama Isthmus giving rise to two lineages, the coastal and mountain lineages, which still coexist in Peru (i.e., T. pallidipennis and T. andeana. Subsequent vicariant and dispersal events continued the differentiation process, giving rise to three to six genetic lineages (i.e., clades detected in this study, which were geographically restricted to locations dispersed over the central Andes Mountains in South America. Our results provide another interesting example of “island diversification” motored by the topography plus unstable climatic conditions during the Pleistocene, pointing out the presence of a hotspot of diversification in the Andean region of Peru.

Morfología periglacial del volcán Llullaillaco (Chile/Argentina

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Schroder, H.

2000-12-01

Full Text Available The periglacial processes in the High Andes and resulting periglacial phenomena are presented here by example of Mt. Llullaillaco, at 24°43’ S and 68°32’W, on the frontier between Argentina and Chile. The landforming processes reflect the recent and present extremely arid climate as well as the different age of the volcanics. The range of periglacial landforms, the vertical distribution and association that are described here, result from the interactions of climate and bedrocks. The upper periglacial limits are the highest of the world. The identified phenomena allow to differentiate between the subandine (below 4,100 m, subandine/andine (4,100-4,300 m, andine (4,300-4,700 m, lower periglacial (4,700-5,800 m, medium periglacial (5,800-6,300 m and upper periglacial (6,300-6,739 m altitudinal zones. Due to the extreme aridity glaciers cannot form today. Their absence therefore is not due to insufficiently low temperatures, but to lack of humidity.

[de]
Die periglaziale Oberflachenformung und der sich daraus ergebende periglaziale Formenschatz werden im Bereich der Hochanden am Beispiel des Llullaillaco bei 24°43' s.Br. und 68°32' w.L. nuf der Grenze zwischen Argentinien und Chile vorgestellt. Die Formungsprozesse spiegeln das subrezent und rezent extrem trockene Klima sowie das unterschiedliche Alter der Vulkanite ivider. Aus den neigungsdifferenzierten Wechselbeziehungen mit Klima und Gestein ergeben sich eine Vielzahl von Periglazialformen, deren hohenwiirtige Verteilung und Vergesellschaftung beschrieben werden. Die periglazialen Hohengrenzen sind die hochsten unserer Erde. Entsprechend dem ausgegliederten Formenschatz konnte zwischen subandiner (unter 4100 m, subandiner/andiner (4100-4300 m, andiner (4300-4700 m, unterer periglazialer (4700-5800 m, mittlerer periglazialer (5800-6300 m und obérer periglazialer Stufe (6300-6739 m unterschieden werden. Die extreme Trockenheit filhrt dazu, dass sich rezent keine Gletscher

Glacier shrinkage and water resources in the Andes

Science.gov (United States)

Francou, Bernard; Coudrain, Anne

For more than a century glaciers around the world have been melting as air temperatures rise due to a combination of natural processes and human activity. The disappearance of these glaciers can have wide-ranging effects, such as the creation of new natural hazards or changes in stream flow that could threaten water suppliesSome of the most dramatic melting has occurred in the Andes mountain range in South America. To highlight the climatic and glacial change in the Andes and to encourage the scientific community to strengthen the glacier observation network that stretches from Colombia to the Patagonian ice fields, the Instituto Nacional de Recursos Naturales (INRENA), Perú, and the Institute of Research and Development (IRD), France, recently organized the second Symposium on Mass Balance of Andean Glaciers in Huaráz,Perú.

Reasons for an outstanding plant diversity in the tropical Andes of Southern Ecuador

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Michael Richter

2009-06-01

Full Text Available Long-term field studies in the scope of a multidisciplinary project in southern Ecuador revealed extraordinary high species numbers of many organismic groups. This article discusses reasons for the outstanding vascular plant diversity using a hierarchical scale-oriented top-down approach (Grüninger 2005, from the global scale to the local microscale. The global scale explains general (paleo- ecological factors valid for most parts of the humid tropics, addressing various hypotheses and theories, such as the “greater effective evolutionary time”, constant input of “accidentals”, the “seasonal variability hypothesis”, the “intermediate disturbance hypothesis”, and the impact of soil fertility. The macroscale focuses on the Andes in northwestern South America. The tropical Andes are characterised by many taxa of restricted range which is particularly true for the Amotape-Huancabamba region, i.e. the so called Andean Depression, which is effective as discrete phytogeographic transition as well as barrier zone. Interdigitation of northern and southern flora elements, habitat fragmentation, geological and landscape history, and a high speciation rate due to rapid genetic radiation of some taxa contribute to a high degree of diversification. The mesoscale deals with the special environmental features of the eastern mountain range, the Cordillera Real and surrounding areas in southern Ecuador. Various climatic characteristics, the orographic heterogeneity, the geologic and edaphic conditions as well as human impact are the most prominent factors augmenting plant species diversity. On microscale, prevailing regimes of disturbance and environmental stresses, the orographic basement, as well as the general role on the various mountain chains are considered. Here, micro-habitats e.g. niches for epiphytes, effects of micro-relief patterns, and successions after small-sized disturbance events are screened. Direct effects of human impact are

Astro Tourism in Chile | CTIO

Science.gov (United States)

Program PIA Program GO-FAAR Program Other Opportunities Tourism Visits to Tololo Astro tourism in Chile Tourism in Chile Information for travelers Visit Tololo Media Relations News Press Release Publications ‹› You are here CTIO Home » Outreach » Tourism » Astro Tourism in Chile Astro Tourism in

Seismicity preliminary results in a geothermal and volcano activity area: study case Liquiñe-Ofqui fault system in Southern Andes, Chile

Science.gov (United States)

Estay, N. P.; Yáñez Morroni, G.; Crempien, J. G. F.; Roquer, T.

2017-12-01

Fluid transport through the crust takes place in domains with high permeability. For this reason, fault damage zones are a main feature where fluids may circulate unimpeded, since they have much larger permeability than normal country rocks. With the location of earthquakes, it is possible to infer fault geometry and stress field of the crust, therefore we can determine potential places where fluid circualtion is taking place. With that purpose, we installed a seismic network in an active volcanic-geothermal system, the Liquiñe-Ofqui Fault System (LOFS), located in Puyuhuapi, Southern Andes (44°-45°S). This allowed to link epicentral seismicity, focal mechanisms and surface expression of fluid circulation (hot-springs and volcanos). The LOFS is composed by two NS-striking dextral master faults, and several secondary NE-striking dextral and normal faults. Surface manifestation of fluid circulation in Puyuhuapi area are: 1) six hot-springs, most of them spatially associated with different mapped faults; 2) seven minor eruptive centers aligned over a 10-km-along one of the master NS-striking fault, and; 3) the Melimouyu strato-volcano without any spatial relationship with mapped faults. The network consists of 6 short period seismometers (S31f-2.0a sensor of IESE, with natural frequency of 2Hz), that were installed between July 2016 and August 2017; also 4 permanent broad-band seismometers (Guralp 6TD/ CD 24 sensor) which belong to the Volcano Observatory of Southern Andes (OVDAS). Preliminary results show a correlation between seismicity and surface manifestation of fluid circulation. Seismicity has a heterogeneous distribution: most of the earthquake are concentrated is the master NS-striking fault with fluid circulation manifestations; however along the segments without surface manifestation of fluids do not have seismicity. These results suggest that fluid circulation mostly occur in areas with high seismicity, and thus, the increment in fluid pressure enhances

Patrones geográficos de distribuci��n de árboles y arbustos en la zona de transición climática mediterráneo-templada de Chile Geographic patterns of distribution of trees and shrubs in the transitional Mediterranean-temperate climatic zone of Chile

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ERNESTO A. TENEB

2004-03-01

Full Text Available Uno de los principales objetivos de la biogeografía es determinar si las especies se distribuyen en el espacio en forma aleatoria o si existen grupos de especies con patrones de distribución comunes. En el presente estudio determinamos a través de técnicas cuantitativas si existen corotipos, es decir, grupos de especies con patrones de distribución común entre los árboles y arbustos en la zona de transición climática mediterráneo-templada de Chile, Octava Región de Chile. Adicionalmente, evaluamos la relación entre el clima y la distribución de los diferentes grupos de árboles y arbustos de la Octava Región. El análisis de agrupamiento de especies permitió definir 24 corotipos significativos, de los cuales 18 responden significativamente con alguna variable ambiental analizada. La temperatura media anual, la temperatura media invernal y la temperatura media de verano resultaron ser las variables que mejor explican el patrón de distribución de la mayoría de los corotipos. Las tendencias geográficas de los corotipos y su relación con las variables ambientales fueron evaluadas mediante un análisis de ordenación. Los resultados señalan que los corotipos con distribución en la cordillera de los Andes se correlacionan con la temperatura de invierno en tanto que los corotipos con distribución costera se correlacionan con la mediterraneidad. Se discute respecto de la utilización de una nueva aproximación para el análisis fitogeográfico y de su utilidad en el estudio de la relación entre la vegetación y los factores ambientales que determinan su distribuciónOne main aim of biogeography is to determine if species are randomly distributed or if there exist groups of species with common distributional patterns known as chorotypes. In this study, we determined through quantitative techniques if there exists such chorotypes for trees and shrubs in the transitional Mediterranean-temperate climatic zone of Chile, Eigth

Palabras y silencios: la retórica del poder en los Andes

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1997-01-01

Full Text Available PAROLES ET SILENCES : LA RETHORIQUE DU POUVOIR DANS LES ANDES. La parole condense différents arguments et formes de pouvoir dans les sociétés andines. Le domaine social et le cadre cérémoniel appartiennent à ceux qui articulent bien les mots. La différenciation entre la valeur octroyée à la parole et celle correspondant aux silences implique diverses modalités de prestige de reconnaissance sociale et de pouvoir rituel dans les Andes. Les personnes, les vivants et les savants exercent une maîtrise subtile de la parole face aux étrangers, aux défunts et aux sots, qui demeurent socialement “muets”, silencieux. La palabra condensa diferentes argumentos y formas de poder en las sociedades andinas. El dominio social y el ámbito ceremonial pertenecen a los buenos articuladores de palabras. La diferenciación entre el valor otorgado a la palabra y el que corresponde a los silencios implica diferentes modalidades de prestigio, reconocimiento social y poder ritual en los Andes. Las personas, los vivos y los sabios ejercen un dominio exquisito de la palabra frente a los extraños, los difuntos y los “necios” que permanecen socialmente “mudos”, callados. WORDS AND SILENCES: THE RHETORIC OF POWER IN THE ANDES. Words have different meanings and means to exercise power in Andean societies. Social power and ceremonial environments belong people who are fluent in language. The difference between the value ascribed to the spoken word and that ascribed to silence implies several kinds of prestige, social recognition and ritual power in the Andes. “Ordinary”, alive and wise people exert an exquisite authority with words as compared with strange, dead and “stupid people” who remain socially 'dumb', silent.

Un réseau d'observation des glaciers dans les Andes tropicales

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1995-01-01

Full Text Available Par leur grande sensibilité au changement climatique, les glaciers tropicaux sont d’excellents indicateurs de l’évolution du climat et, en même temps, des objets hydrologiques susceptibles d’évoluer rapidement dans le futur. On montre que l’actuel recul accéléré des glaciers dans les Andes centrales et les conséquences qu’il peut avoir en matière hydrologique et de risques naturels rendent nécessaire un programme de surveillance de ces glaciers au niveau de toute la chaîne, ce que l’ORSTOM contribue à faire depuis 1991. UNA RED DE OBSERVACIÓN DE LOS GLACIARES EN LOS ANDES TROPICALES. Por su gran sensibilidad al cambio climático, los glaciares tropicales son excelentes indicadores de la evolución del clima, así como objectos hidrológicos susceptibles de una evolución rápida en el futuro. Considerando el actual retroceso acelerado de los glaciares en los Andes centrales y las consecuencias que puede tener a nivel hidrológico así como en el campo de los riesgos naturales, es necesario un programa de monitoreo de los glaciares a nivel de toda la cordillera, que es lo que ORSTOM contribuye a hacer desde 1991. A GLACIER MONITORING NETWORK IN THE TROPICAL ANDES. The high sensibility of Tropical glaciers to climatic forcing make it possible to use them as reliable indicators of climate evolution, as well as hydrological systems which could change rapidly in the future. Considering the present increase in glacier retreat in central Andes and the consequences induced by this evolution on water resources and natural hazards, a monitoring program at a large scale appears to be highly desirable. This has been the objective of ORSTOM since 1991.

An InSAR-based survey of volcanic deformation in the central Andes

Science.gov (United States)

Pritchard, M. E.; Simons, M.

2004-02-01

We extend an earlier interferometric synthetic aperture radar (InSAR) survey covering about 900 remote volcanos of the central Andes (14°-27°S) between the years 1992 and 2002. Our survey reveals broad (10s of km), roughly axisymmetric deformation at 4 volcanic centers: two stratovolcanoes are inflating (Uturuncu, Bolivia, and Hualca Hualca, Peru); another source of inflation on the border between Chile and Argentina is not obviously associated with a volcanic edifice (here called Lazufre); and a caldera (Cerro Blanco, also called Robledo) in northwest Argentina is subsiding. We explore the range of source depths and volumes allowed by our observations, using spherical, ellipsoidal and crack-like source geometries. We further examine the effects of local topography upon the deformation field and invert for a spherical point-source in both elastic half-space and layered-space crustal models. We use a global search algorithm, with gradient search methods used to further constrain best-fitting models. Inferred source depths are model-dependent, with differences in the assumed source geometry generating a larger range of accepted depths than variations in elastic structure. Source depths relative to sea level are: 8-18 km at Hualca Hualca; 12-25 km for Uturuncu; 5-13 km for Lazufre, and 5-10 km at Cerro Blanco. Deformation at all four volcanoes seems to be time-dependent, and only Uturuncu and Cerro Blanco were deforming during the entire time period of observation. Inflation at Hualca Hualca stopped in 1997, perhaps related to a large eruption of nearby Sabancaya volcano in May 1997, although there is no obvious relation between the rate of deformation and the eruptions of Sabancaya. We do not observe any deformation associated with eruptions of Lascar, Chile, at 16 other volcanoes that had recent small eruptions or fumarolic activity, or associated with a short-lived thermal anomaly at Chiliques volcano. We posit a hydrothermal system at Cerro Blanco to explain the

Influence of Biological Factors on Connectivity Patterns for Concholepas concholepas (loco in Chile.

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Lysel Garavelli

Full Text Available In marine benthic ecosystems, larval connectivity is a major process influencing the maintenance and distribution of invertebrate populations. Larval connectivity is a complex process to study as it is determined by several interacting factors. Here we use an individual-based, biophysical model, to disentangle the effects of such factors, namely larval vertical migration, larval growth, larval mortality, adults fecundity, and habitat availability, for the marine gastropod Concholepas concholepas (loco in Chile. Lower transport success and higher dispersal distances are observed including larval vertical migration in the model. We find an overall decrease in larval transport success to settlement areas from northern to southern Chile. This spatial gradient results from the combination of current direction and intensity, seawater temperature, and available habitat. From our simulated connectivity patterns we then identify subpopulations of loco along the Chilean coast, which could serve as a basis for spatial management of this resource in the future.

The GNSS Component of the Seismic Monitoring System in Chile

Science.gov (United States)

Barrientos, S. E.

2016-12-01

Chile is amongst the most seismically active countries in the world. Since mid-XVI Century, a magnitude 8 or more earthquake has taken place every dozen of years, as an average. In the last 100 years, more than ten events with magnitudes around 8 or larger have taken place in this part of world. Three events with M>8 have taken place only in the last six years. The largest earthquake ever recorded took place in May, 1960, in southern Chile. Such extreme seismic activity is the result of the interaction of the Nazca, Antarctic, Scotia and South American plates in southwestern South America where Chile is located. These megathrust earthquakes exhibit long rupture regions reaching several hundreds of km with fault displacements of several tens of meters. At least eighteen of these earthquakes have generated local tsunamis with runups larger than 4 m -including events in 2010, 2014 and 2015- therefore it is mandatory to establish a system with capabilities to rapidly evaluate the tsunamigenic potential of these events. In 2013, the newly created National Seismological Center (CSN) of the University of Chile was tasked to upgrade the countrýs seismic network by increasing the numbers of real-time monitoring stations. The most important change to previous practices is the establishment of a GNSS network composed by 130 devices, in addition to the incorporation of 65 new collocated broadband and strong motion instruments. Additional 297 strong motion instruments for engineering purposes complement the system. Forty units -of the 130 devices- present an optional RTX capability, where satellite orbits and clock corrections are sent to the field device producing a 1-Hz position stream at 4-cm level. First records of ground displacement -using this technology-were recorded at the time of the largest aftershock (Mw=7.6) of the sequence that affected northern Chile in 2014. The CSN is currently developing automatic detectors and amplitude estimators of displacement from the

Distribution and habitat ecology of the sorediate species of Menegazzia (Parmeliaceae, lichenized Ascomycota in Chile Distribución y ecología de las especies sorediosas de Menegazzia (Parmeliaceae, Ascomycota liquenizado en Chile

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JARLE W BJERKE

2003-03-01

Full Text Available ABSTRACT The taxonomy and ecology of the sorediate species of Menegazzia from the southernmost regions of Chile and Argentina and the South Atlantic Islands was recently published, only with sporadic reports from the more northern regions. In the present work the distribution patterns and habitat ecology of the sorediate species are discussed, with emphasis on the area north of 48º S. Eleven species are treated. Menegazzia subpertusa, an epiphyte of sclerophyll scrubs, is recorded from South America for the first time (Chile and Argentina. Menegazzia neozelandica has a disjunct distribution in Chile, with occurrences in Fray Jorge (Fourth Region of Chile and on Islas Juan Fernández, and along the coast south of latitude 38º S. Menegazzia kawesqarica and M. tenuis are most common in the southernmost part of Chile, but are also found at high altitudes at lower latitudes. Additional treated species are M. chrysogaster, M. fumarprotocetrarica, M. globulifera, M. magellanica, M. norsorediata, M. sanguinascens and M. wandae. Several of the sorediate species are early colonisers of newly developed substrates. They show variable occurrences along light and humidity gradients. Distribution maps and a revised key are presented.Recientemente se han publicado datos sobre la taxonomía y ecología de las especies sorediosas de Menegazzia representadas en las regiones más australes de Chile y Argentina e islas del Atlántico Sur, además de registros esporádicos en zonas ubicadas más al norte en Chile. En este trabajo se discuten los patrones de distribución y la ecología del hábitat de 11 especies sorediosas, con especial enfásis en aquellas que se desarrollan al norte de los 48º S. Menegazzia subpertusa, un epífito de arbustos esclerófilos, se registra por primera vez en América (Chile y Argentina. Menegazzia neozelandica tiene una distribución discontinua en Chile; ha sido recolectada en Fray Jorge (Cuarta Región de Chile, Islas Juan Fern

Cosmogenic 10Be Dating of Early and Latest Holocene Moraines on Nevado Salcantay in the Southern Peruvian Andes

Science.gov (United States)

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

2007-12-01

A two-fold sequence of nested lateral and end moraines was mapped in a glacial trough emanating from the southwest flank of Nevado Salcantay (6271 m; ~13°S latitude), the highest peak in the Cordillera Vilcabamba of southern Peru. The field area is situated 25 km due south of the archaeological site of Machu Picchu. Outer and inner moraines in the sequence were deposited by valley glaciers that terminated ~5 km and ~3 km, respectively, from their headwall on the Salcantay summit massif. Cosmogenic 10Be surface exposure dating of granitic boulders sampled on the Salcantay moraines is underway and has provided the first numerical ages for these deposits. Initial results indicate ages of 8.1 ± 0.1 10Be ka for the outer moraine and 200 ± 20 10Be years for the sharp-crested inner moraine. These ages are derived using the CRONUS-Earth 10Be exposure age calculator (version 2.0) and expressed with respect to the Lal- Stone production rate scaling scheme using the standard atmosphere. The outer and inner moraine ages correspond to glacial events during the early and latest Holocene, respectively. Further 10Be dating of the mapped moraines and similar deposits observed in adjacent drainages on Nevado Salcantay is anticipated to yield a high-resolution chronology of valley glaciation in this segment of the southern Peruvian Andes. The new results bridge an important gap between existing Andean glacier records to the north and south, and complement available ice core and lacustrine paleoclimate records in the vicinity, thereby expanding spatial and temporal coverage for identifying patterns of Holocene climate change in the tropical Andes. Notably, the inner moraine age correlates with the timing of the Little Ice Age as defined in northern mid- and high latitude glacier records, and suggests considerable expansion of valley glaciers in the southern Peruvian Andes during this climatic minimum. Apart from their paleoclimatic significance, the initial results also demonstrate

La formacion de anillos de crecimiento en Fissurella crassa en el norte de Chile

OpenAIRE

Bretos, Marta

1980-01-01

Growth discontinuity in molluscs result in the formation of rings on their shells. Two kind of rings may be formed: disturbance and growth rings. Growth rings can be used to determine the age of molluscs with long life span. For this, it is necessary to know how many growth rings are formed per year. It has been demonstrated experimentally, using marked specimens, that F. crassa forms two growth rings per year at Huayquique, Northern Chile. They are formed during winter and summer. Disturbanc...

Biochemical features of a Protoceratium reticulatum red tide in Chipana Bay (Northern Chile in summer conditions

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Sergio Rossi

2010-11-01

Full Text Available Protoceratium reticulatum is considered a potential toxic dinoflagellate. This paper describes a high-frequency monitoring study performed at Chipana Bay (northern Chile, sampling over 48 hours in a near-bottom shallow coastal area to quantify the biochemical features of a red tide dominated by this microscopic algae. This area belongs to the Humboldt Current upwelling system, and is considered highly productive for artisanal fisheries. Total chlorophyll a, total lipids, particulate organic carbon and nitrogen, fatty acids and major phytoplankton group concentration (i.e. dinoflagellates, diatoms, ciliates and cysts were studied in 7-hour intervals in February 2007. Our results indicate a high concentration of potential available food in the form of lipids ranging from 50 to 300 μg L-1 for benthic suspension feeders, i.e. bivalves. The dominance of P. reticulatum (60-80% of the total cell concentration per litre, ranging from 55x103 to 384x103 cells L-1 can be considered as a possible interference for harvesting in this productive area, although the toxicity of this algae was not proved in the present study. The main dinoflagellate fatty acid markers [18:0, 18:4(n-3, 20:5(n-3, and 22:6(n-3] showed high proportions (% during the short time cycle and in at least two cases [the 18:4 (n-3 and 22:6 (n-3 fatty acids] a highly significant relationship with dinoflagellate concentration (cells L-1. The topographical and benthic structure (mainly kelp forest of the zone helps to retain particles and nutrients that may in part explain the high productivity and food availability, but the presence of recurrent red tides in this coastal area—if they prove to be toxic—is argued to be a major problem for local fisheries.

Ontogenetic Responses of Calanus chilensis to Hypoxia from Northern Chile (23ºS), Humboldt Current Ecosystem

Science.gov (United States)

Ruz, P. M.; Hidalgo, P.; Escribano, R.; Franco-Cisterna, B.; Yebra, L.; Keister, J. E.

2016-02-01

Eastern Boundary Upwelling Systems are being subjected to expansion, intensification and shoaling of Oxygen Minimum Zones (OMZ's), as a result of ongoing climate change. To understand how dominant epipelagic copepods may respond to stressful conditions induced by low oxygen, we experimentally studied the effect of hypoxia over the stage-specific physiology of Calanus chilensis from the Mejillones Bay (23°S — 70°W), northern Chile, during the winters of 2013 and 2014. Females, eggs and nauplii (NI to NIV) of C. chilensis were incubated under hypoxia ( 0.7 mg O2 L-1) and normoxia ( 8.3 mg O2 L-1) conditions at a constant temperature of 14ºC as to estimate egg production rate (EPR), hatching success (HS) and naupliar growth and development time. Additionally, we estimated survivorship by using Neutral Red technique, and also examined female metabolism by measuring specific activity of the enzymes Aminoacyl-tRNA synthetases (spAARS) (growth index) and the electron transport system (spETS) (potential respiration). Survival of females and EPR were not significantly affected by dissolved oxygen (DO) conditions, coinciding with no significant changes in their metabolism. By contrast, HS was reduced from normoxia (70%) to hypoxia (30%), whereas naupliar growth (NI to NIII) was lower under hypoxia (0.155 ± 0.007 d-1) than normoxia (0.237 ± 0.006 d-1), resulting also in a longer development time, 6.490 ± 0.353 d and 4.238 ± 0.149 d, respectively. Most eggs and nauplii collected at the end of the experiments were alive, although a higher proportion of organisms were recovered in normoxia than hypoxia. Our results revealed stage-specific responses to hypoxia in C. chilensis and the importance of ontogenetic responses to variable levels of oxygenation in the upwelling zone.

Glacier mass balance reconstruction by sublimation induced enrichment of chemical species on Cerro Tapado (Chilean Andes

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P. Ginot

2006-01-01

Full Text Available A 36 m long ice core down to bedrock from the Cerro Tapado glacier (5536 m a.s.l, 30°08' S, 69°55' W was analyzed to reconstruct past climatic conditions for Northern Chile. Because of the marked seasonality in the precipitation (short wet winter and extended dry summer periods in this region, major snow ablation and related post-depositional processes occur on the glacier surface during summer periods. They include predominantly sublimation and dry deposition. Assuming that, like measured during the field campaign, the enrichment of chloride was always related to sublimation, the chemical record along the ice core may be applied to reconstruct the history of such secondary processes linked to the past climatic conditions over northern Chile. For the time period 1962–1999, a mean annual net accumulation of 316 mm water equivalent (weq and 327 mm weq loss by sublimation was deduced by this method. This corresponds to an initial total annual accumulation of 539 mm weq. The annual variability of the accumulation and sublimation is related with the Southern Oscillation Index (SOI: higher net-accumulation during El-Niño years and more sublimation during La Niña years. The deepest part of the ice record shows a time discontinuity; with an ice body deposited under different climatic conditions: 290 mm higher precipitation but with reduced seasonal distribution (+470 mm in winter and –180 mm in summer and –3°C lower mean annual temperature. Unfortunately, its age is unknown. The comparison with regional proxy data however let us conclude that the glacier buildup did most likely occur after the dry mid-Holocene.

The effect of drainage on organic matter accumulation and plant communities of high-altitude peatlands in the Colombian tropical Andes

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J.C. Benavides

2014-04-01

Full Text Available The tropical Andes store and regulate water outflow that serves nearly 60 million people. Most of the water is for un-managed agricultural irrigation. In this work I report how the drainage of peatlands has adversely affected the development of plant communities and recent carbon accumulation in a páramo massif at 2500 to 3800 m altitude in the northern Andes. I surveyed vegetation and water chemistry in 26 peatlands with differing intensities of drainage. Peat cores to 50 cm from two sites with contrasting drainage histories were dated using 210Pb, and used to compare historical vegetation changes and carbon accumulation rates. (A Species composition was much affected by drainage, which resulted in a reduction in cover of Sphagnum and other peat-forming species, and the encroachment of sedges and Juncus effusus. The ability of peat to store water and carbon was also reduced in drained peatlands. Vegetation records show a shift towards sedge-Juncus communities around 50 years ago when agricultural use of water increased. (B Peat and carbon accumulation rates were lower in drained sites, indicating either greater decomposition rates of the upper peat column or lower production by the changed plant communities. The ecological services offered by peatlands to agrarian communities downstream are important. Measures to prevent peatland destruction are needed urgently.

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.

Modernitet og forbrugskultur i Chile

DEFF Research Database (Denmark)

Cristoffanini, Pablo Rolando

2012-01-01

I de sidste årtier er Chile blevet et egentligt forbrugersamfund. Udbredelsen af forbrugskulturen og forbrugerismen er centrale fænomener i chilenernes dagligliv og har nået et omfang, som har konsekvenser for de borgere, der ikke kan deltage fuldt ud heri, noget som er typisk for et samfund med en...... ujævn økonomisk udvikling og med store sociale forskelle. Denne proces er ikke et produkt af en stille, fredelig og naturlig samfundsudvikling, således som magteliten og de toneangivende intellektuelle i Chile har fremstillet det. Som jeg vil vise, er skabelsen af et egentlig forbrugssamfund knyttet til...... til i dag. Ifølge disse er Chile blevet et moderne samfund netop i kraft af, at Chile er et ægte forbrugersamfund med alt, hvad dette indebærer, såvel materielt som symbolsk. For det tredje er billedet af Chile som en ”supermoderne” nation i den latinamerikanske kontekst en udbredt forestilling hos...

conelchilenoresistentearte, Solidaridad: Chile Vive, una Exposición en España contra el Chile Dictatorial withthechileanresistantart, Solidarity: Chile Vive, an Exposition in Spain against the Dictatorial Chile

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Francisco Godoy

2010-12-01

Full Text Available En 1987 se realiza en Madrid Chile Vive, megaexposición que incluye diferentes manifestaciones artísticas para dar cuenta de la vitalidad cultural de Chile en dictadura. El ensayo, partiendo de una discusión conceptual sobre el problema de la exposición de arte latinoamericano en el extranjero, analiza la configuración de esta exposición, centrándose en las artes visuales como alineación unitaria de un discurso político de país, además de examinar su repercusión en la prensa española de la época. Por otro lado, reflexiona sobre las inclusiones y exclusiones de artistas y las proyecciones de Chile Vive en el problema de la exposición del arte chileno en el extranjero, particularmente el de un periodo tan complejo como el producido durante la dictadura militar.In 1987, Chile Vive, a mega-exhibition that included different artistic expressions, was performed in Madrid to inform people about the cultural vitality of Chile during their dictatorship. This essay will focus on a conceptual discussion about the problem of Latin American art exhibitions abroad. It will analyze the configuration of the mentioned exhibition, focusing on visual arts as a unitary alignment of a political discourse of nation. The text will also examine the repercussion in the Media of Spain in that period of time. On the other hand, the article will develop some thoughts on the artists incorporations, exclusions and projections of Chile Vive, focusing on why the exhibition of Chilean art abroad might be problematic, particularly the ones that belongs to this complex period of time; the military dictatorship.

Distribution of Euphausia mucronata at the upwelling area of Peninsula Mejillones, northern Chile: The influence of the oxygen minimum layer

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R. Escribano

2000-03-01

Full Text Available Analysis of zooplankton samples from 53 stations obtained around Peninsula Mejillones (Northern Chile, from two strata: 0-50 m and 150-200 m, during active upwelling in December 1996, allowed the study of horizontal and vertical distribution of Euphausia mucronata, endemic Krill of the Humboldt Current. Information from CTDO and a fluorometer was used to analyze the influence of oceanographic variables on distribution of E. mucronata. E. mucronata was found distributed all around the Peninsula, although with greater aggregations in the southern area, especially in the deeper layer. Stepwise multiple regression showed that none of the variables (temperature, salinity and chlorophyll was significantly correlated to numerical abundance of the species. However there was a significant effect of depth of the oxygen minimum layer (OML, defined as 0.5 ml O2 l-1, on integrated abundance of the species, such that individuals are more likely to be found in areas where the OML is deeper. A vertical distribution parameter suggested a diurnal migrational pattern. This parameter was also correlated with distance to shoreline. The OML rises abrutply in nearshore areas because of active upwelling, but there are still nearshore zones where the OML remains deep. Therefore E. mucronata appears to aggregate around the upwelling lenses and filaments, where phytoplankton is more concentrated, but at the same time avoiding places where the OML is too shallow.

Gastrointestinal parasites of Lamas in the Bolivian Andes

DEFF Research Database (Denmark)

Nissen, Anne Malene; Nees, Ellinor Spörndly; Monrad, Jesper

A cross sectional study was conducted to determine prevalences and intensities of gastrointestinal (GIT) parasites in lamas in the Bolivian Andes. A quantitative and qualitative necro-copro-parasitlogical study was performed on 33 lamas between October and December 2007. At the time of necropsy t...

Migmatization and low-pressure overprinting metamorphism as record of two pre-Cretaceous tectonic episodes in the Santander Massif of the Andean basement in northern Colombia (NW South America)

Science.gov (United States)

Zuluaga, C. A.; Amaya, S.; Urueña, C.; Bernet, M.

2017-03-01

The core of the Santander Massif in the northern Andes of Colombia is dominated by migmatitic gneisses with a 7.5 kbar. Lithologies are overprinted by low-pressure metamorphism, related to extensive Jurassic intrusions and linked with growth of cordierite and equilibration of low-pressure mineral assemblages, recorded metamorphic conditions are Pangaea.

Reflections on Andes' Goal-Free User Interface

Science.gov (United States)

VanLehn, Kurt

2016-01-01

Although the Andes project produced many results over its 18 years of activity, this commentary focuses on its contributions to understanding how a goal-free user interface impacts the overall design and performance of a step-based tutoring system. Whereas a goal-aligned user interface displays relevant goals as blank boxes or empty locations that…

Loco or no loco? Holocene climatic fluctuations, human demography and community base management of coastal resources in northern Chile

Science.gov (United States)

Santoro, Calogero M.; Gayo, Eugenia M.; Carter, Chris; Standen, Vivien G.; Castro, Victoria; Valenzuela, Daniela; De Pol-Holz, Ricardo; Marquet, Pablo A.; Latorre, Claudio

2017-10-01

The abundance of the southern Pacific mollusk loco (Concholepas concholepas), among other conspicuous marine supplies, are often cited as critical resources behind the long-term cultural and demographic fluctuations of prehistoric hunter-gatherers at the coastal Atacama Desert. These societies inhabited one of the world’s most productive marine environments flanked by one the world’s driest deserts. Both of these environments have witnessed significant ecological variation since people first colonized them at the end of the Pleistocene (c. 13,000 cal yr BP). Here, we examine the relationship between the relative abundance of shellfish (a staple resource) along a 9,500-year sequence of archaeological shell midden accumulations at Caleta (a small inlet or cove) Vitor, with past demographic trends (established via summed probability distributions of radiocarbon ages) and technological innovations together with paleoceanographic data on past primary productivity. We find that shellfish extraction varied considerably from one cultural period to the next in terms of the number of species and their abundance, with diversity increasing during periods of regionally decreased productivity. Such shifts in consumption patterns are considered community based management decisions, and for the most part they were synchronous with large and unusual regional demographic fluctuations experienced by prehistoric coastal societies in northern Chile. When taken together with their technological innovations, our data illustrates how these human groups tailored their socio-cultural patterns to what were often abrupt and prolonged environmental changes throughout the Holocene.

Loco or no Loco? Holocene Climatic Fluctuations, Human Demography, and Community Based Management of Coastal Resources in Northern Chile

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Calogero M. Santoro

2017-10-01

Full Text Available The abundance of the southern Pacific mollusk loco (Concholepas concholepas, among other conspicuous marine supplies, are often cited as critical resources behind the long-term cultural and demographic fluctuations of prehistoric hunter-gatherers in the coastal Atacama Desert. These societies inhabited one of the world's most productive marine environments flanked by one the world's driest deserts. Both of these environments have witnessed significant ecological variation since people first colonized them at the end of the Pleistocene (c. 13,000 cal yr BP. Here, we examine the relationship between the relative abundance of shellfish (a staple resource along a 9,500-year sequence of archeological shell midden accumulations at Caleta (a small inlet or cove Vitor, with past demographic trends (established via summed probability distributions of radiocarbon ages and technological innovations together with paleoceanographic data on past primary productivity. We find that shellfish extraction varied considerably from one cultural period to the next in terms of the number of species and their abundance, with diversity increasing during periods of regionally decreased productivity. Such shifts in consumption patterns are considered community based management decisions, and for the most part they were synchronous with large and unusual regional demographic fluctuations experienced by prehistoric coastal societies in northern Chile. When taken together with their technological innovations, our data illustrates how these human groups tailored their socio-cultural patterns to what were often abrupt and prolonged environmental changes throughout the Holocene.

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

Applications of NASA Earth Observation Imagery in Google Earth Engine to Estimate Glacier Trends and Water Availability in Chile's Aconcagua Watershed

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Webb, M. J.; Babis, B.; Deland, S.; McGurk, G.

2017-12-01

The Aconcagua basin of Central Chile, just north of the capital city of Santiago, is characterized by the glaciated Andes to the east, which supply meltwater runoff to the lower fertile river valleys. Known for the production of fruit and vegetable crops, the region is experiencing stressed hydrologic resources as a result of anomalous climate conditions and anthropogenic water consumption. Traditionally, the wet and cool winter months account for 80 percent of Aconcagua's total annual precipitation, while dry and warm conditions prevail during the summer months. Consequently, the basin depends on seasonal glacial accumulation to provide water storage for the dry season when up to 67 percent of water is derived from glacial runoff. Overall, 70 percent of regional water is consumed by agricultural practices, specifically the fruit and vegetable farming that thrives in Aconcagua's Mediterranean-type climate. Globally, weather intensification and the rising zero-degree isotherm are poised to threaten the stability and longevity of glacial water resources. In recent years, Chile has experienced periods of prolonged drought as well as glacier shrinkage. The Aconcagua basin is especially vulnerable to these changes as a consequence of its agricultural economies and reliance on sub-tropical glaciers for water resources. Aconcagua is among the top three regions contributing to Chile's gross domestic product (GDP). Furthermore, in 2011 the Chilean government announced plans to increase the national land under irrigation by 57 percent by 2022. In partnership with the Chilean Ministry of Agriculture, the objective of this research was to integrate NASA Earth observations in conjunction with in situ river discharge measurements into Google Earth Engine to enhance regional understanding of current and future climate conditions in Chile. The remotely-sensed datasets included Landsat TM/OLI derived glacial extent, Terra MODIS snow cover and surface temperature, and Aqua AMSR

A first insight on the population structure of Mycobacterium tuberculosis complex as studied by spoligotyping and MIRU-VNTRs in Santiago, Chile.

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Balcells, María Elvira; García, Patricia; Meza, Paulina; Peña, Carlos; Cifuentes, Marcela; Couvin, David; Rastogi, Nalin

2015-01-01

Tuberculosis (TB) remains a significant public health problem worldwide, but the ecology of the prevalent mycobacterial strains, and their transmission, can vary depending on country and region. Chile is a country with low incidence of TB, that has a geographically isolated location in relation to the rest of South American countries due to the Andes Mountains, but recent migration from neighboring countries has changed this situation. We aimed to assess the genotypic diversity of Mycobacterium tuberculosis complex (MTBC) strains in Santiago, Chile, and compare with reports from other Latin-American countries. We analyzed MTBC isolates from pulmonary tuberculosis cases collected between years 2008 and 2013 in Central Santiago, using two genotyping methods: spoligotyping and 12-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTRs). Data obtained were analyzed and compared to the SITVIT2 database. Mean age of the patients was 47.5 years and 61% were male; 11.6% were migrants. Of 103 strains (1 isolate/patient) included, there were 56 distinct spoligotype patterns. Of these, 16 strains (15.5%) corresponded to orphan strains in the SITVIT2 database, not previously reported. Latin American and Mediterranean (LAM) (34%) and T (33%) lineages were the most prevalent strains, followed by Haarlem lineage (16.5%). Beijing family was scarcely represented with only two cases (1.9%), one of them isolated from a Peruvian migrant. The most frequent clustered spoligotypes were SIT33/LAM3 (10.7%), SIT53/T1 (8.7%), SIT50/H3 (7.8%), and SIT37/T3 (6.8%). We conclude that LAM and T genotypes are the most prevalent genotypes of MTBC in Santiago, Chile, and together correspond to almost two thirds of analyzed strains, which is similar to strain distribution reported from other countries of Latin America. Nevertheless, the high proportion of SIT37/T3, which was rarely found in other Latin American countries, may underline a specific history or

Between Andes and Amazon: the genetic profile of the Arawak-speaking Yanesha.

Science.gov (United States)

Barbieri, Chiara; Heggarty, Paul; Yang Yao, Daniele; Ferri, Gianmarco; De Fanti, Sara; Sarno, Stefania; Ciani, Graziella; Boattini, Alessio; Luiselli, Donata; Pettener, Davide

2014-12-01

The Yanesha are a Peruvian population who inhabit an environment transitional between the Andes and Amazonia. They present cultural traits characteristic of both regions, including in the language they speak: Yanesha belongs to the Arawak language family (which very likely originated in the Amazon/Orinoco lowlands), but has been strongly influenced by Quechua, the most widespread language family of the Andes. Given their location and cultural make-up, the Yanesha make for an ideal case study for investigating language and population dynamics across the Andes-Amazonia divide. In this study, we analyze data from high and mid-altitude Yanesha villages, both Y chromosome (17 STRs and 16 SNPs diagnostic for assigning haplogroups) and mtDNA data (control region sequences and 3 SNPs and one INDEL diagnostic for assigning haplogroups). We uncover sex-biased genetic trends that probably arose in different stages: first, a male-biased gene flow from Andean regions, genetically consistent with highland Quechua-speakers and probably dating back to Inca expansion; and second, traces of European contact consistent with Y chromosome lineages from Italy and Tyrol, in line with historically documented migrations. Most research in the history, archaeology and linguistics of South America has long been characterized by perceptions of a sharp divide between the Andes and Amazonia; our results serve as a clear case-study confirming demographic flows across that 'divide'. © 2014 The Authors. American journal of physical Anthropology published by Wiley Periodocals, Inc.

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

Science.gov (United States)

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.

Across and along arc geochemical variations in altered volcanic rocks: Evidence from mineral chemistry of Jurassic lavas in northern Chile, and tectonic implications

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Rossel, Pablo; Oliveros, Verónica; Ducea, Mihai N.; Hernandez, Laura

2015-12-01

Postmagmatic processes mask the original whole-rock chemistry of most Mesozoic igneous rocks from the Andean arc and back-arc units preserved in Chile. Mineral assemblages corresponding to subgreenschist metamorphic facies and/or propylitic hydrothermal alteration are ubiquitous in volcanic and plutonic rocks, suggesting element mobility at macroscopic and microscopic scale. However, fresh primary phenocrysts of clinopyroxene and plagioclase do occur in some of the altered rocks. We use major and trace element chemistry of such mineral phases to infer the geochemical variations of four Jurassic arc and four back-arc units from northern Chile. Clinopyroxene belonging to rocks of the main arc and two units of the bark-arc are augites with low contents of HFSE and REE; they originated from melting of an asthenospheric mantle source. Clinopyroxenes from a third back-arc unit show typical OIB affinities, with high Ti and trace element contents and low Si. Trace elemental variations in clinopyroxenes from these arc and back-arc units suggest that olivine and clinopyroxene were the main fractionating phases during early stages of magma evolution. The last back-arc unit shows a broad spectrum of clinopyroxene compositions that includes depleted arc-like augite, high Al and high Sr-Ca diopside (adakite-like signature). The origin of these lavas is the result of melting of a mixture of depleted mantle plus Sr-rich sediments and subsequent high pressure fractionation of garnet. Thermobarometric calculations suggest that the Jurassic arc and back-arc magmatism had at least one crustal stagnation level where crystallization and fractionation took place, located at ca. ~ 8-15 km. The depth of this stagnation level is consistent with lower-middle crust boundary in extensional settings. Crystallization conditions calculated for high Al diopsides suggest a deeper stagnation level that is not consistent with a thinned back-arc continental crust. Thus minor garnet fractionation

The effect of offset on fracture permeability of rocks from the Southern Andes Volcanic Zone, Chile

Science.gov (United States)

Pérez-Flores, P.; Wang, G.; Mitchell, T. M.; Meredith, P. G.; Nara, Y.; Sarkar, V.; Cembrano, J.

2017-11-01

The Southern Andes Volcanic Zone (SVZ) represents one of the largest undeveloped geothermal provinces in the world. Development of the geothermal potential requires a detailed understanding of fluid transport properties of its main lithologies. The permeability of SVZ rocks is altered by the presence of fracture damage zones produced by the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). We have therefore measured the permeability of four representative lithologies from the volcanic basement in this area: crystalline tuff, andesitic dike, altered andesite and granodiorite. For comparative purposes, we have also measured the permeability of samples of Seljadalur basalt, an Icelandic rock with widely studied and reported hydraulic properties. Specifically, we present the results of a systematic study of the effect of fractures and fracture offsets on permeability as a function of increasing effective pressure. Baseline measurements on intact samples of SVZ rocks show that the granodiorite has a permeability (10-18 m2), two orders of magnitude higher than that of the volcanic rocks (10-20 m2). The presence of throughgoing mated macro-fractures increases permeability by between four and six orders of magnitude, with the highest permeability recorded for the crystalline tuff. Increasing fracture offset to produce unmated fractures results in large increases in permeability up to some characteristic value of offset, beyond which permeability changes only marginally. The increase in permeability with offset appears to depend on fracture roughness and aperture, and these are different for each lithology. Overall, fractured SVZ rocks with finite offsets record permeability values consistent with those commonly found in geothermal reservoirs (>10-16 m2), which potentially allow convective/advective flow to develop. Hence, our results demonstrate that the fracture damage zones developed within the SVZ produce permeable regions, especially within the

Association of vectors and environmental conditions during the emergence of Peruvian horse sickness orbivirus and Yunnan orbivirus in northern Peru.

Science.gov (United States)

Méndez-López, María R; Attoui, Houssam; Florin, David; Calisher, Charles H; Florian-Carrillo, J Christian; Montero, Stephanie

2015-12-01

Since 1983, cases of diseased donkeys and horses with symptoms similar to those produced by alphaviruses were identified in two departments in northern Peru; however serological testing ruled out the presence of those viruses and attempts to isolate an agent were also unproductive. In 1997, also in northern Peru, two new orbiviruses were discovered, each recognized as a causative agent of neurological diseases in livestock and domestic animals and, at the same time, mosquitoes were found to be infected with these viruses. Peruvian horse sickness virus (PHSV) was isolated from pools of culicid mosquitoes, Aedes serratus and Psorophora ferox, and Yunnan virus (YUOV) was isolated from Aedes scapularis in the subtropical jungle (upper jungle) located on the slope between the east side of the Andes and the Amazonian basin in the Department of San Martín. Both viruses later were recovered from mosquitoes collected above the slope between the west side of the Andes and the coast (Department of Piura) in humid subtropical areas associated with the Piura River basin. In this region, PHSV was isolated from Anopheles albimanus and YUOV was isolated from Ae. scapularis. We discuss the ecology of vector mosquitoes during the outbreaks in the areas where these mosquitoes were found. © 2015 The Society for Vector Ecology.

Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes

Energy Technology Data Exchange (ETDEWEB)

Herrera, Christian, E-mail: cherrera@ucn.cl [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Custodio, Emilio [Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona (Spain); Chong, Guillermo [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Lambán, Luis Javier [Geological Institute of Spain (IGME), Zaragoza (Spain); Riquelme, Rodrigo; Wilke, Hans [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Jódar, Jorge [Department of Geo-Engineering, Technical University of Catalonia/Barcelona Tech (UPC), Barcelona (Spain); Urrutia, Javier; Urqueta, Harry [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Centro de Investigación Tecnológica del Agua en el Desierto (CEITSAZA), Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); Sarmiento, Alvaro [Departamento de Ciencias Geológicas, Universidad Católica del Norte, Casilla 1280, Antofagasta (Chile); and others

2016-01-15

Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200 mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water–rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ{sup 18}O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano. - Highlights: • Recent volcanism formations play a key role in producing recharge. • Groundwater can flow across local

Groundwater flow in a closed basin with a saline shallow lake in a volcanic area: Laguna Tuyajto, northern Chilean Altiplano of the Andes

International Nuclear Information System (INIS)

Herrera, Christian; Custodio, Emilio; Chong, Guillermo; Lambán, Luis Javier; Riquelme, Rodrigo; Wilke, Hans; Jódar, Jorge; Urrutia, Javier; Urqueta, Harry; Sarmiento, Alvaro

2016-01-01

Laguna Tuyajto is a small, shallow saline water lake in the Andean Altiplano of northern Chile. In the eastern side it is fed by springs that discharge groundwater of the nearby volcanic aquifers. The area is arid: rainfall does not exceed 200 mm/year in the rainiest parts. The stable isotopic content of spring water shows that the recharge is originated mainly from winter rain, snow melt, and to a lesser extent from some short and intense sporadic rainfall events. Most of the spring water outflowing in the northern side of Laguna Tuyajto is recharged in the Tuyajto volcano. Most of the spring water in the eastern side and groundwater are recharged at higher elevations, in the rims of the nearby endorheic basins of Pampa Colorada and Pampa Las Tecas to the East. The presence of tritium in some deep wells in Pampa Colorada and Pampa Las Tecas indicates recent recharge. Gas emission in recent volcanoes increase the sulfate content of atmospheric deposition and this is reflected in local groundwater. The chemical composition and concentration of spring waters are the result of meteoric water evapo-concentration, water–rock interaction, and mainly the dissolution of old and buried evaporitic deposits. Groundwater flow is mostly shallow due to a low permeability ignimbrite layer of regional extent, which also hinders brine spreading below and around the lake. High deep temperatures near the recent Tuyajto volcano explain the high dissolved silica contents and the δ"1"8O shift to heavier values found in some of the spring waters. Laguna Tuyajto is a terminal lake where salts cumulate, mostly halite, but some brine transfer to the Salar de Aguas Calientes-3 cannot be excluded. The hydrogeological behavior of Laguna Tuyajto constitutes a model to understand the functioning of many other similar basins in other areas in the Andean Altiplano. - Highlights: • Recent volcanism formations play a key role in producing recharge. • Groundwater can flow across local

Registro nuevo de Amphipyrinae en Chile A new record of Amphipyrinae from Chile

Directory of Open Access Journals (Sweden)

Tania S. Olivares

2006-12-01

Full Text Available Se registra por primera vez en Chile la especie Agrotisia subhyalina Hampson, entre las latitudes 18° 29' S 70° 20' O hasta 29° 54' S 71° 16' O (I-IV regiones en Chile. Se redescriben los genitales del macho y de la hembra y se presentan algunos aspectos taxonómicos de la especie.The species Agrotisia subhyalina Hampson is recorded for the first time from Chile (18° 29' S 70° 20' W to 29° 54' S 71° 16' W, I to IV Chilean regions. Redescriptions of male and female are presented, along with some taxonomic aspects of the species.

Current Discussions Between ESO and Chile

Science.gov (United States)

1995-04-01

[Joint Press Release by the Government of the Republic of Chile and the European Southern Observatory. The text is issued simultaneously in Santiago de Chile (in Spanish) and at the ESO Headquarters in Garching (in English).] Today, Tuesday, 18 April 1995, at the ESO Headquarters in Garching (Germany), Mr. Roberto Cifuentes, Plenipotentiary Ambassador representing the Government of the Republic of Chile, and the Director General of the European Southern Observatory, Professor Riccardo Giacconi, have signed a Supplementary, Interpretative and Amending Agreement to the Convention of 6 November 1963 which governs the relations between Chile and this International Organisation. This Agreement which in practice signifies a widening and strengthening of the cooperative relations between the Organisation and the Chilean scientific community will hereafter be submitted for ratification by the National Congress of the Republic of Chile (the Parliament) and by the ESO Council. According to the Agreement signed today, Chilean astronomers will have privileged access within up to 10 percent observing time on all present and future ESO telescopes in Chile. Moreover, ESO accepts to incorporate into its labour regulations for Chilean personnel concepts like freedom of association and collective bargaining. This signing of the Supplementary, Interpretative and Amending Agreement to the original Convention of 1963 follows after months of constructive dialogue between the parties. It constitutes an important step towards a solution of some of the pending points on the current agenda for discussions between the Government of Chile and ESO. Among the issues still pending, ESO has informed the Government of Chile that respect for its immunities by the Chilean State is of vital importance for the continuation of the construction of the world's largest telescope at Paranal, as well as the continued presence of the Organisation in Chile. The Chilean Government, on its side, and concerning

Estructura de la población antigua de la costa norte de Chile

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Cocilovo, José Alberto

2003-01-01

Full Text Available El poblamiento arcaico del Área Centro Sur Andina, iniciado en los albores del XI milenio AP., es producido por cazadores y recolectores que ocupan progresivamente el área altiplánica, los valles fluviales y las cuencas intermedias derivados de grupos paleoindios. El proceso de dispersión que involucra la exploración, conquista y adaptación a distintos ambientes, biotopos y ecosistemas produjo la fragmentación de la población original de los cazadores holocénicos tempranos (11000-8000 AP y su progresiva divergencia genética posiblemente asociada con diferentes modelos adaptativos propuestos por la arqueología (Núñez y Santoro, 1990. Si bien los registros bioantropológicos de épocas tan tempranas son sumamente escasos, la estructura de la población antigua se proyecta en el tiempo permitiendo explicar la variación geográfica de los grupos arcaicos tardíos y formativos. En el presente informe se analizan los resultados de varios trabajos realizados con materiales bien cronometrados para explicar el poblamiento de la costa norte de Chile. Se emplearon datos métricos y no métricos obtenidos en relevamientos modernos de sitios de la costa de Arica y Valle de Azapa, Pisagua, Norte Semiárido y Zona Central de Chile. Se analizan y discuten distintos modelos elaborados para comprender el proceso microevolutivo a nivel local, suponiendo un desarrollo en relativo aislamiento moderado por eventos demográficos dependientes de acontecimientos económicos y sociopolíticos de rango medio a nivel regional (transhumancia y de rango amplio (migraciones, originados en el área circuntiticaca y en los Andes Centrales que determinaron al final, la configuración de las sociedades multiétnicas del Período Tardío.

Internationalization of SMES: business opportunities in Chile

OpenAIRE

Correia, João Filipe Amado

2016-01-01

The main goal of this study is to identify the main business opportunities in Chile, legal advantages in the business perspective and entry strategies for small and medium sized enterprises (SMEs). The methodology used was qualitative, by conducting several interviews with chamber of commerce representative from Portugal in Chile and Chile in Portugal, several young entrepreneurs from different nations operating in Chile, the CEO of a Spanish company that decided to not internationalize to...

Glacier loss and hydro-social risks in the Peruvian Andes

Science.gov (United States)

Mark, Bryan G.; French, Adam; Baraer, Michel; Carey, Mark; Bury, Jeffrey; Young, Kenneth R.; Polk, Molly H.; Wigmore, Oliver; Lagos, Pablo; Crumley, Ryan; McKenzie, Jeffrey M.; Lautz, Laura

2017-12-01

Accelerating glacier recession in tropical highlands and in the Peruvian Andes specifically is a manifestation of global climate change that is influencing the hydrologic cycle and impacting water resources across a range of socio-environmental systems. Despite predictions regarding the negative effects of long-term glacier decline on water availability, many uncertainties remain regarding the timing and variability of hydrologic changes and their impacts. To improve context-specific understandings of the effects of climate change and glacial melt on water resources in the tropical Andes, this article synthesizes results from long-term transdisciplinary research with new findings from two glacierized Peruvian watersheds to develop and apply a multi-level conceptual framework focused on the coupled biophysical and social determinants of water access and hydro-social risks in these settings. The framework identifies several interacting variables-hydrologic transformation, land cover change, perceptions of water availability, water use and infrastructure in local and regional economies, and water rights and governance-to broadly assess how glacier change is embedded with social risks and vulnerability across diverse water uses and sectors. The primary focus is on the Santa River watershed draining the Cordillera Blanca to the Pacific. Additional analysis of hydrologic change and water access in the geographically distinct Shullcas River watershed draining the Huaytapallana massif towards the city of Huancayo further illuminates the heterogeneous character of hydrologic risk and vulnerability in the Andes.

The atypical Caribbean-Colombia oceanic plateau and its role in the deformation of the Northern Andes

Science.gov (United States)

Ferrari, L.; Lopez-Martinez, M.; Petrone, C. M.; Serrano, L.

2013-05-01

The Late Cretaceous to Early Tertiary tectono-magmatic evolution of the Northern Andes has been strongly influenced by the dextral oblique interaction of the Caribbean-Colombian oceanic plateau (CCOP) with northwestern South America. This complex interaction has resulted in several pulses of transpressional deformation and crustal accretion to the South America plate but also in a widespread deformation in the plateau itself. In this peculiar type of orogeny one of the factors controlling the deformation is the crustal structure and thus the rheological profiles of the two lithospheric sections that interact. The genesis of the CCOP has been traditionally associated to the melting of the Galapagos plume head when it impacted the Farallon plate, which is supposed to have built an unsubductable and thick crustal section. This interpretation was based on the apparent clustering of ages at ~91-89 Ma for several obducted fragments of the CCOP in northwestern South America and in the Caribbean islands. However, seismic profiles show that magmatism added a very variable amount but no more than 10 km of igneous material to the original crust of the Farallon plate, making the CCOP much more irregular than other oceanic plateaus. Recent studies of key areas of the obducted part of the CCOP contradict the notion that the plateau formed by melting of a plume head at ~ 90 Ma. Particularly, new geochronologic data and petrologic modeling from the small Gorgona Island document a magmatic activity spanning the whole Late Cretaceous (98.7±7.7 to 64.4±5 Ma) and a progressive increase in the degree of melting and melt extraction with time. Multiple magmatic pulses over several tens of Ma in small areas like Gorgona, are also recognized in other areas of the CCOP, documenting a long period of igneous activity with peaks at 74-76, 80-82, and 88-90 Ma in decreasing order of importance. Even older, Early Cretaceous ages, have been reported for fragments in Costa Rica and Curaçao. A

Estimation of slip scenarios of mega-thrust earthquakes and strong motion simulations for Central Andes, Peru

Science.gov (United States)

Pulido, N.; Tavera, H.; Aguilar, Z.; Chlieh, M.; Calderon, D.; Sekiguchi, T.; Nakai, S.; Yamazaki, F.

2012-12-01

all scenario slips for central Andes, and for an average soil condition, exhibit similar amplitudes and attenuation characteristics with distance as the PGA and PGV values observed during the 2010 Maule (Mw 8.8), and 2011 Tohoku-oki (Mw 9.0) earthquakes. Our results clearly indicate that the simulated ground motions for scenarios with deep rupture nucleations (~40 km) are consistently smaller than the ground motions obtained for shallower rupture nucleations. We also performed strong ground motion simulations in metropolitan Lima by using the aforementioned slip scenarios, and incorporating site amplifications obtained from several microtremors array surveys conducted at representative geotechnical zones in this city. Our simulated PGA and PGV in Lima reach values of 1000 cm/s^2 and 80 cm/s. Our results show that the largest values of PGA (at Puente Piedra district, Northern Lima) are related with short period site effects, whereas the largest values of PGV are related with large site amplifications for periods from 1s to 1.5s (at Callao, Villa el Salvador and La Molina districts). Our results also indicate that the simulated PGA and PGV in central Lima (Parque de la Reserva) are in average 2~3 times larger than the values recorded by a strong motion instrument installed at this location, during the 1974 (Mw8.0) and 1966 (Mw8.0) earthquakes off-shore Lima.

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.

Dynamics of a Puelche foehn event in the Andes

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Lea Beusch

2018-01-01

Full Text Available In this numerical modelling study, we investigate a Puelche foehn event (25–26 March 2014 in the southern Andes – a region with sparse observations. The synoptic environment as well as the mesoscale structure and the dynamics of the easterly wind are examined with European Centre for Medium-Range Weather Forecasts (ECMWF analyses and a simulation with the mesoscale non-hydrostatic limited-area weather prediction model COSMO with a grid spacing of 2.2 km.The large-scale synoptic situation leading to this Puelche event is characterized by a mid-tropospheric cut-off low above the mountain range, the formation of a coastal surface low, as well as high pressure extending over the southern Andes. Easterly winds extend throughout the entire troposphere, indicative of a deep foehn flow. In the free troposphere, the easterlies are geostrophically balanced and develop in association with increasing pressure to the south. In contrast, within the planetary boundary layer, the easterly winds occur predominantly due to an increasing cross-range large-scale pressure gradient with only a weak geostrophic component. Kinematic trajectories indicate that a significant part of the Puelche air mass originates from above an inversion on the upstream side of the Andes. Some air parcels, however, ascend on the upstream side to crest height as the boundary layer deepens during daytime and/or flow through gaps across the mountain range. Hence, this Puelche event shares characteristics of both a blocked and a non-blocked foehn type.

Calculate the high solar radiation for photovoltaic panels in Chile; Aproximacio al calculo de la oferta de energia por paneles fotovoltaicos en Chile

Energy Technology Data Exchange (ETDEWEB)

Cancino, Beatriz; Roth, Pedro; Stolz, German [Universidad Tecnica Federico Santa Maria, Valparaiso (Chile); Bonneschky, Alexis [Cottbus University, Cottbus (Germany)

2000-07-01

The aim of this work was to develop a method which permits to calculate and predict the theoretically possible electrical energy which can be obtained in different places in Chile with photovoltaic panels used in solar home systems. Chile is a country with a high solar radiation, specially in its northern part, between parallels 18 degrees with a daily mean energy of 4600 Wh/m{sup 2} over the year and 37 degrees, with 3700 Wh/m{sup 2}. Therefore, the use of photovoltaic power is an interesting alternative to be studied and used. Nevertheless, the photovoltaic possibilities have not been studied and no evaluation of real possibilities exist. In a previous paper, the absence of an installation guide for solar home systems have been mentioned. And also the lack of information regarding the real electrical energy needs of people. This work pretends to be the first approximation to a detailed chart and list of possible electric supplies using photovoltaic panels in different locations of Chile. It is made with a computer program which permits to calculate the solar radiation on a tilted surface, on a hourly bases. It uses geographical data and the daily average of monthly radiation. Therefore, the hourly energy, harnessed by the panel can be established and the total energy for some place calculated. [Spanish] El objetivo de este trabajo, es el de mostrar a traves de un listado y un mapa nacional, la cantidad teorica de energia electrica que puede ser obtenida a traves del uso de paneles fotovoltaicos principalmente destinados a Solar Home System (SHS) en Chile. Chile es un pais con una alta oferta de energia solar ubicada principalmente en la zona norte y centro del pais, aproximadamente entre los paralelos 18 grados (sobre 4600 Wh/m{sup 2} dia promedio anual) y 37 grados Sur (sobre 3700 Wh/m{sup 2} dia promedio anual). Por lo que el uso de paneles fotovoltaicos representa una alternativa interesante de ser estudiada y aprovechada. Sin embargo, no existe una evaluacion

La formación de anillos de crecimiento en Fissurella crassa en el norte de Chile

OpenAIRE

Marta Bretos

1980-01-01

Growth discontinuity in molluscs result in the formation of rings on their shells. Two kind of rings may be formed: disturbance and growth rings. Growth rings can be used to determine the age of molluscs with long life span. For this, it is necessary to know how many growth rings are formed per year. It has been demonstrated experimentally, using marked specimens, that F. crassa forms two growth rings per year at Huayquique, Northern Chile. They are formed during winter and summer. Disturbanc...

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

-Columbian cultures." Archaeometry 47: 137-185. Miller, D. C. and P. W. Birkeland (1992). "Soil catena variation along an alpine climatic transect, northern Peruvian Andes." Geoderma 55(3): 211-223. Schittek, K., et al. (2014). "Holocene environmental changes in the highlands of the southern Peruvian Andes (14° S) and their impact on pre-Columbian cultures." Climate of the past discussions 10: 1707-1746.

Las infracomunidades de parásitos de dos especies de Scartichthys (Pisces: Blenniidae en localidades cercanas del norte de Chile Parasite infracommunities of two blennid species, Scartichthys (Pisces: Blenniidae, at nearby localities off northern Chile

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KAREN FLORES

2009-03-01

Full Text Available Se comparan las infracomunidades de parásitos de dos especies congenéricas y simpátridas de peces marinos: Scartichthys viridis (Valenciennes 1836 y Scartichthys gigas (Steindachner 1876 (Pisces: Blenniidae, en tres localidades del intermareal rocoso de Iquique (20°32' S, 70°11' O, norte de Chile, separadas por no más de 6 km, con muestras recolectadas entre agosto y septiembre de 2005. El objetivo fue evaluar la variabilidad de la riqueza, abundancia, diversidad, dominancia y composición en una escala espacial y temporal reducida. En total, se recolectaron 2.110 individuos parásitos en los 134 hospedadores examinados, los que pertenecían a 14 taxa. Se encontró una gran similitud en la composición y en las propiedades agregadas de las infracomunidades, tanto entre especies de hospedadores como entre sitios de estudio. Se interpreta que las condiciones ambientales, los factores ecológicos como el uso del habitat y de los recursos alimentarios, y los factores evolutivos como el alto grado de parentesco de estas especies de Scartichthys, son las principales influencias en la alta similitud parasitaria encontrada.The infracommunities of metazoan parasites in two congeneric and sympatric marine fish species, Scartichthys viridis (Valenciennes 1836 and Scartichthys gigas (Steindachner 1876, were studied and compared between three localities of the intertidal rocky shore off the coast of northern Chile, near Iquique (20°32' S, 70°11' W, which were separated by no more than 6 km. Samples were collected between August and September 2005. The goal of this study was to assess the variability in richness, abundance, diversity, dominance and parasite composition between close localities sampled within a short period. In all, 2,110 parasite individuals were collected from the 134 hosts examined, and 14 parasite taxa were identified. There was great similarity in the aggregated and compositional properties of the infracommunities, both between

Rule of Repression in Chile.

Science.gov (United States)

American Indian Journal, 1979

1979-01-01

This report on the current condition of the Mapuche Indians of Chile is edited from a document on the "Situation of Human Rights in Chile" and details the repressive and inhumane treatment of the largest indigenous ethnic minority in the country. (Author/RTS)

Evidence for Cenozoic extensional basin development and tectonic inversion south of the flat-slab segment, southern Central Andes, Chile (33° 36°S.L.)

Science.gov (United States)

Charrier, R.; Baeza, O.; Elgueta, S.; Flynn, J. J.; Gans, P.; Kay, S. M.; Muñoz, N.; Wyss, A. R.; Zurita, E.

2002-04-01

The mainly volcanic Cenozoic deposits that make up much of the western part of the Principal Cordillera in Central Chile are generally subdivided into two major units: an older Abanico or Coya-Machalí Formation and a younger Farellones Formation. Difficulty in differentiating these units has led to considerable debate. On the basis of the wide distribution, great thickness, and presence of sedimentary intercalations, it has been postulated that these arc volcanics were deposited in an intermontane basin; more recently, it has been proposed that this basin developed under extensional conditions and underwent subsequent tectonic inversion. We present field, geochronologic, geochemical, and thermal maturity data that support the latter interpretation. Collectively, this new information clarifies the stratigraphic, tectonic, and paleogeographic evolution of these deposits. The vast geographic extent of the Abanico Formation and lateral equivalents, which reach from at least 32°30' to 44°S along the Principal Cordillera, its great thickness, and the presence of repeated thick fluvial and lacustrine intercalations all indicate deposition in a large, strongly subsident, and probably north-south oriented basin, developed between middle to late Eocene and Oligocene. The unconformable contact with underlying Mesozoic units observed at several localities indicates that deposition followed a substantial erosional episode during late Cretaceous and/or early Cenozoic time. Basal deposits of the Abanico Formation near Termas del Flaco increase rapidly in thickness to the west. Still further to the west, a thick Abanico section contains, in its upper part, mammal fossils older than those found in the basal deposits near Termas. This evidence indicates a major space of deposition west of this locality, which had been filled before deposition took place at Termas. The east-vergent, high-angle El Fierro thrust fault on the east side of the westward-growing deposits is interpreted

Screening for new accumulator plants in Andes Range mines

Science.gov (United States)

Bech, Jaume; Roca, Núria

2016-04-01

accumulated considerable concentrations of Cu and Zn. The species from the genus Bidens (Asteraceae) were able not only to accumulate high shoot As concentrations (> 1000 μg g-1 in B. cynapiifolia from Peru) but also considerable amounts of Pb (B. humilis from Chile). The highest Cu shoot concentrations were found in Mullinum spinosum (870 μg g-1) and in B. cynapiifolia (620 μg g-1). The shoot accumulation of Zn was highest in Baccharis amdatensis (>1900 μg g-1) and in Rumex crispus (1300 μg g-1) from the Ag mine in Ecuador (Bech et al., 2002). In the Peruvian Andes, B. triplinervia can be considered interesting for phytostabilization, due to its capacity to restrict the accumulation of elevated amounts of Pb and Zn in the shoots.

Artemia (Crustacea, Anostraca in Chile: a review of basic and applied biology Artemia Crustacea, Anostraca en Chile: revisión de la biología básica y aplicada

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Patricio De los Rios-Escalante

2012-09-01

Full Text Available The brine shrimp Artemia in Chile has been studied since the 1980s, initially on populations inhabiting shallow coastal and inland mountain ponds, and saltworks in northern and central Chile. Based on morphometric and molecular evidence, these populations were identified as A. franciscana. In the 1990s, A. persimilis was recorded from southern Patagonia, a species previously considered endemic to Argentina. Recently, two new populations of A.franciscana have been recorded, from one saline coastal pond in northern Chile and from a saltwork in central Chile. The scope for further research to increase both understanding of the strain characterization and basic population ecology descriptions of the Chilean brine shrimps and improve their conservation status is discussed. It is suggested that future studies should investigate first the management of local brine shrimp population for local aquaculture or conservation resources, other direction would be the effects of ultraviolet radiation (UVR exposition that is notoriously high in brine shrimp habitats. This last factor is very important because the UVR is an important mutagen on the genetic structure of the populations. In this scenario, it is suggest a carefully management for introduced brine shrimp populations for local aquaculture for avoid alterations in native populations that due their genetic isolation would need conservation procedures for avoid local extinctions.El camarón de salmuera o Artemia ha sido estudiado en Chile desde la década de 1980, las primeras descripciones de poblaciones fueron para lagunas someras en zonas costeras y de montana, y en salinas artificiales en la zona central y norte de Chile. Sobre la base de evidencias morfométricas y moleculares estas poblaciones fueron descritas como A. franciscana. En la década de 1990, se describió la presencia de A. persimilis en la zona sur de la Patagonia, lo cual fue una ampliación del rango de distribución significativa

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Platform for Exchange between African Research Scientists and ... Argentina, South America, Brazil, Chile, Mexico, North And Central America ... Organic farming in the Peruvian Andes ... Integrated crop and goat breeding in Tanzania.

Constraining the hydration of the subducting Nazca plate beneath Northern Chile using subduction zone guided waves

Science.gov (United States)

Garth, Tom; Rietbrock, Andreas

2017-09-01

Guided wave dispersion is observed from earthquakes at 180-280 km depth recorded at stations in the fore-arc of Northern Chile, where the 44 Ma Nazca plate subducts beneath South America. Characteristic P-wave dispersion is observed at several stations in the Chilean fore-arc with high frequency energy (>5 Hz) arriving up to 3 s after low frequency (accounted for if dipping low velocity fault zones are included within the subducting lithospheric mantle. A grid search over possible LVL and faults zone parameters (width, velocity contrast and separation distance) was carried out to constrain the best fitting model parameters. Our results imply that fault zone structures of 0.5-1.0 km thickness, and 5-10 km spacing, consistent with observations at the outer rise are present within the subducted slab at intermediate depths. We propose that these low velocity fault zone structures represent the hydrated structure within the lithospheric mantle. They may be formed initially by normal faults at the outer rise, which act as a pathway for fluids to penetrate the deeper slab due to the bending and unbending stresses within the subducting plate. Our observations suggest that the lithospheric mantle is 5-15% serpentinised, and therefore may transport approximately 13-42 Tg/Myr of water per meter of arc. The guided wave observations also suggest that a thin LVL (∼1 km thick) interpreted as un-eclogitised subducted oceanic crust persists to depths of at least 220 km. Comparison of the inferred seismic velocities with those predicted for various MORB assemblages suggest that this thin LVL may be accounted for by low velocity lawsonite-bearing assemblages, suggesting that some mineral-bound water within the oceanic crust may be transported well beyond the volcanic arc. While older subducting slabs may carry more water per metre of arc, approximately one third of the oceanic material subducted globally is of a similar age to the Nazca plate. This suggests that subducting oceanic

Tracking Hydrothermal Fluid Pathways from Surface Alteration Mineralogy: The Case of Licancura Geothermal Field, Northern Chile

Science.gov (United States)

Camus, E.; Elizalde, J. D.; Morata, D.; Wechsler, C.

2017-12-01

In geothermal systems alteration minerals are evidence of hot fluid flow, being present even in absence of other surface manifestations. Because these minerals result from the interaction between geothermal fluids and surrounding host rocks, they will provide information about features of thermal fluids as temperature, composition and pH, allowing tracking their changes and evolution. In this work, we study the Licancura Geothermal field located in the Andean Cordillera in Northern Chile. The combination of Principal Components Analysis on ASTER-L1T imagery and X Ray Diffraction (XRD) allow us to interpret fluid conditions and the areas where fluid flow took place. Results from red, green, blue color composite imagery show the presence of three types of secondary paragenesis. The first one corresponds to hematite and goethite, mainly at the east of the area, in the zone of eroded Pliocene volcanic edifices. The second one, mainly at the center of the area, highlighting propylitic alteration, includes minerals such as chlorite, illite, calcite, zeolites, and epidote. The third paragenesis, spatially related to the intersection between faults, represents advanced argillic alteration, includes minerals as alunite, kaolinite, and jarosite. XRD analysis support results from remote sensing techniques. These results suggest an acid pH hydrothermal fluid reaching temperatures at surface up to 80-100°C, which used faults as a conduit, originating advanced argillic minerals. The same fluid was, probably, responsible for propylitic paragenesis. However, iron oxides paragenesis identified in the area of eroded volcanoes probably corresponds to other processes associated with weathering rather than geothermal activity. In this work, we propose the applicability of remote sensing techniques as a first level exploration tool useful for high-altitude geothermal fields. Detailed clay mineral studies (XRD and SEM) would allow us to a better characterization of the geothermal fluid

Primer registro del frutero pechinegro Pipreola lubomirskii (Aves, Cotingidae en la vertiente occidental de los Andes

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Letty Salinas

2013-06-01

Full Text Available El frutero pechinegro, Pipreola lubomirskii, es un cotíngido registrado como raro y de distribución local en los Andes del Norte. Antes del presente registro sólo había sido reportado para la vertiente oriental del Perú y Ecuador, así como los Andes del sur de Colombia. El presente registro amplia su distribución a los bosques montañosos de la vertiente occidental de los Andes peruanos, habiéndose encontrado en los bosques nublados del valle del río Zaña, en el departamento de Cajamarca (6º50’-6º52’ latitud S, 79º10’-79º07’ longitud O.

Interseismic Coupling, Co- and Post-seismic Slip: a Stochastic View on the Northern Chilean Subduction Zone

Science.gov (United States)

Jolivet, R.; Duputel, Z.; Simons, M.; Jiang, J.; Riel, B. V.; Moore, A. W.; Owen, S. E.

2017-12-01

Mapping subsurface fault slip during the different phases of the seismic cycle provides a probe of the mechanical properties and the state of stress along these faults. We focus on the northern Chile megathrust where first order estimates of interseismic fault locking suggests little to no overlap between regions slipping seismically versus those that are dominantly aseismic. However, published distributions of slip, be they during seismic or aseismic phases, rely on unphysical regularization of the inverse problem, thereby cluttering attempts to quantify the degree of overlap between seismic and aseismic slip. Considering all the implications of aseismic slip on our understanding of the nucleation, propagation and arrest of seismic ruptures, it is of utmost importance to quantify our confidence in the current description of fault coupling. Here, we take advantage of 20 years of InSAR observations and more than a decade of GPS measurements to derive probabilistic maps of inter-seismic coupling, as well as co-seismic and post-seismic slip along the northern Chile subduction megathrust. A wide InSAR velocity map is derived using a novel multi-pixel time series analysis method accounting for orbital errors, atmospheric noise and ground deformation. We use AlTar, a massively parallel Monte Carlo Markov Chain algorithm exploiting the acceleration capabilities of Graphic Processing Units, to derive the probability density functions (PDF) of slip. In northern Chile, we find high probabilities for a complete release of the elastic strain accumulated since the 1877 earthquake by the 2014, Iquique earthquake and for the presence of a large, independent, locked asperity left untapped by recent events, north of the Mejillones peninsula. We evaluate the probability of overlap between the co-, inter- and post-seismic slip and consider the potential occurrence of slow, aseismic slip events along this portion of the subduction zone.

Rapid Diversification and Time Explain Amphibian Richness at Different Scales in the Tropical Andes, Earth's Most Biodiverse Hotspot.

Science.gov (United States)

Hutter, Carl R; Lambert, Shea M; Wiens, John J

2017-12-01

The Tropical Andes make up Earth's most species-rich biodiversity hotspot for both animals and plants. Nevertheless, the ecological and evolutionary processes underlying this extraordinary richness remain uncertain. Here, we examine the processes that generate high richness in the Tropical Andes relative to other regions in South America and across different elevations within the Andes, using frogs as a model system. We combine distributional data, a newly generated time-calibrated phylogeny for 2,318 frog species, and phylogenetic comparative methods to test the relative importance of diversification rates and colonization times for explaining Andean diversity at different scales. At larger scales (among regions and families), we find that faster diversification rates in Andean clades most likely explain high Andean richness. In contrast, at smaller temporal and spatial scales (within family-level clades within the Andes), diversification rates rarely explain richness patterns. Instead, we show that colonization times are important for shaping elevational richness patterns within the Andes, with more species found in habitats colonized earlier. We suggest that these scale-dependent patterns might apply to many other richness gradients. Recognition of this scale dependence may help to reconcile conflicting results among studies of richness patterns across habitats, regions, and organisms.

AREAS OF ENDEMISM IN THE SOUTHERN CENTRAL ANDES

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Lone Aagesen

2012-01-01

Full Text Available Este trabajo analiza la distribución de especies de plantas vasculares endémicas de la porción sur de los Andes centrales (sudoeste de Bolivia y noroeste de Argentina. En el análisis se incluyeron 540 especies endémicas de la región estudiada (aproximadamente 720.600 km2. La mayoría de las especies endémicas se halla en ambientes semiáridos, entre 1500-3500 m s.m., encontrándose principalmente en valles, laderas y mesetas del topográficamente complejo sur de los Andes centrales. Las áreas de endemismos aquí halladas se presentan consecuentemente en ambientes áridos y no en ambientes húmedos subtropicales de las Yungas tucumano-bolivianas, a pesar de que en esta última región la diversidad de plantas vasculares es mayor. Se identificaron un total de 17 patrones de distribución bien definidos, y parcialmente solapados. El patrón de distribución más amplio define un área general de endemismos para los Andes centrales. Esta área se extiende a lo largo de casi toda la región y está delimitada por especies que se distribuyen en ambientes desérticos a sub-húmedos en laderas, valles o regiones altoandinas. Casi todas las restantes áreas de endemismo se encuentran anidadas dentro del patrón de distribución amplio antes citado, superponiéndose en el sentido norte-sur a lo largo de pendientes y valles de los Andes y de las Sierras Pampeanas. A pesar del sesgo observado en la distribución hacia ambientes áridos, aproximadamente la mitad de las especies endémicas están restringidas a unas pocas áreas de alto endemismo, las que se encuentran en yuxtaposición con las zonas más lluviosas de la región. Estas áreas de alto endemismo incluyen los rangos de hábitat más amplios de la región en términos de altitud y precipitación, siendo las especies endémicas igualmente variables en sus requerimientos de humedad y elevación. Las unidades fitogeográficas previamente definidas por diversos autores no fueron encontradas

Microevolution of human archaic groups of Arica, northern Chile, and its genetic contribution to populations from the Formative Period Microevolución de grupos humanos arcaicos de Arica, norte de Chile, y su contribución genética a las poblaciones del Período Formativo

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HÉCTOR HUGO VARELA

2006-06-01

Full Text Available The microevolution of the archaic populations from Chile's northern coast and its morphological contribution to Formative period groups was studied. The sample comprised 181 individuals belonging to two Archaic (Morro-Uhle and Morro 1-1/6 and one Formative (Playa Miller-7 [Plm-7] series of the coast and one sample from the Formative (Alto Ramírez exhumed at the Azapa Valley. A total of 29 metric variables of the cranium were analyzed. Biological variability was assessed using discriminant analysis and Mahalanobis' D² distance stadistic (MDS. Population structure was inferred using a method based on quantitative genetic theory that predicts a lineal relationship between average within-group phenotypic variance and group distance to the population centroid. The four samples studied proved to be different from a morphologic point of view. The greatest distance was observed between Plm-7 (coast Formative and Alto Ramirez (valley Formative, the least between Morro-Uhle and Morro 1-1/6, the remaining distances presenting intermediate values. Regarding the total population, the most divergent group was Alto Ramírez and the least divergent was Morro1-1/6. A gradual biologic change was observed between Archaic (Morro Uhle and Morro 1-1/6 and coastal Formative populations (Plm-7 pointing to a morphological (genetic contribution of Archaic fishermen to Formative population of Chile's northern coast, without excluding gene flow from other groups of the South Central Andean AreaEstudiamos la microevolución de las poblaciones arcaicas de la costa norte y sus contribuciones morfológicas al Período Formativo. La muestra comprendió 181 individuos pertenecientes a dos colecciones arcaicas de la costa (Morro-Uhle y Morro 1-1/6 y una al formativo (Alto Ramírez exhumada en el Valle de Azapa. Un total de 29 variables métricas del cráneo fueron analizadas. La variabilidad biológica fue determinada utilizando análisis discriminante y distancias de

Global Albedo

Science.gov (United States)

2002-01-01

Once home to the powerful Inca Empire, the spectacular vistas and canyons of the South American Andes are now a favorite to mountain bikers, climbers and other tourists looking for an adventure. This true color image of the Central Andes and surrounding landscape was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. The dark green area to the right of the brown mountains are the Gran Chaco planes, which consist mostly of alluvial fans and wetlands. To the west is the Pacific Ocean. In the upper half of this image, the Andes are formed by two distinct mountain ranges that appear as darker reddish-brown bands running northwest to southeast. Between the two ranges, shown in a lighter brown, sits the Altiplano plateau, which spans southern Peru and northern Bolivia. The plateau sits at 3660 meters (12,000 feet) and is covered in mazelike canyons, marshlands and lakes. The largest of the lakes-Lake Titticaca-can be seen as the dark blue patch in southern Peru. The two mountain ranges supporting the plateau eventually come together along the border of Argentina and Chile to form one continuous range. The Andes have been forming over the past 170 million years as the Nazca Plate lying under the Pacific Ocean has forced its way under the South American Plate and pushed up its western edge. The subduction of one plate under the other has given rise to a number of volcanoes that dot the western edge of the mountain range. Earthquakes are also very common in this region. Image by NASA GSFC, based on data from the MODIS science team.

Preferences for berries among consumers in southern Chile: blueberries are produced but are they consumed?

Science.gov (United States)

Schnettler, Berta; Miranda, Horacio; Sepúlveda, José; Denegri, Marianela; Mora, Marcos; Lobos, Germán

2011-09-01

Blueberry plantations in Chile are oriented exclusively towards exports to northern hemisphere countries; however, this fruit has recently been introduced into the domestic market due to the increased supply and a fall in export market prices. Based on the previously mentioned, the objectives of the present study were to evaluate consumer preferences for 3 species of berries (blueberries, strawberries, and raspberries), sold loose (unpackaged) as opposed to packaged and branded, at different prices, in one of the principal blueberry producing areas of Chile; and to distinguish consumer segments by their preferences. To do this a survey was applied to 400 people in the Araucanía Region of southern Chile, who were responsible for purchasing fruit for their households. Conjoint analysis showed a preference for raspberries and strawberries over blueberries, packaged and branded, at the lowest price. Total of 2 principal segments were distinguished by cluster analysis: "price sensitive" (42.7%), who preferred strawberries, and "sensitive to species of berry" (47.5%), who preferred raspberries and strawberries. The segments presented different profiles in their demographic make-up and fruit consumption behavior. Strategies are discussed that might reverse the low acceptance of blueberries in the Chilean domestic market. This study presents information on the introduction of new fresh foods into the market. © 2011 Institute of Food Technologists®

Developing services for climate impact and adaptation baseline information and methodologies for the Andes

Science.gov (United States)

Huggel, C.

2012-04-01

Impacts of climate change are observed and projected across a range of ecosystems and economic sectors, and mountain regions thereby rank among the hotspots of climate change. The Andes are considered particularly vulnerable to climate change, not only due to fragile ecosystems but also due to the high vulnerability of the population. Natural resources such as water systems play a critical role and are observed and projected to be seriously affected. Adaptation to climate change impacts is therefore crucial to contain the negative effects on the population. Adaptation projects require information on the climate and affected socio-environmental systems. There is, however, generally a lack of methodological guidelines how to generate the necessary scientific information and how to communicate to implementing governmental and non-governmental institutions. This is particularly important in view of the international funds for adaptation such as the Green Climate Fund established and set into process at the UNFCCC Conferences of the Parties in Cancun 2010 and Durban 2011. To facilitate this process international and regional organizations (World Bank and Andean Community) and a consortium of research institutions have joined forces to develop and define comprehensive methodologies for baseline and climate change impact assessments for the Andes, with an application potential to other mountain regions (AndesPlus project). Considered are the climatological baseline of a region, and the assessment of trends based on ground meteorological stations, reanalysis data, and satellite information. A challenge is the scarcity of climate information in the Andes, and the complex climatology of the mountain terrain. A climate data platform has been developed for the southern Peruvian Andes and is a key element for climate data service and exchange. Water resources are among the key livelihood components for the Andean population, and local and national economy, in particular for

Wildfires in Chile: A review

Science.gov (United States)

Úbeda, Xavier; Sarricolea, Pablo

2016-11-01

This paper reviews the literature examining the wildfire phenomenon in Chile. Since ancient times, Chile's wildfires have shaped the country's landscape, but today, as in many other parts of the world, the fire regime - pattern, frequency and intensity - has grown at an alarming rate. In 2014, > 8000 fires were responsible for burning c. 130,000 ha, making it the worst year in Chile's recent history. The reasons for this increase appear to be the increment in the area planted with flammable species; the rejection of these landscape modifications on the part of local communities that target these plantations in arson attacks; and, the adoption of intensive forest management practices resulting in the accumulation of a high fuel load. These trends have left many native species in a precarious situation and forest plantation companies under considerable financial pressure. An additional problem is posed by fires at the wildland urban interface (WUI), threatening those inhabitants that live in Chile's most heavily populated cities. The prevalence of natural fires in Chile; the relationship between certain plant species and fire in terms of seed germination strategies and plant adaptation; the relationship between fire and invasive species; and, the need for fire prevention systems and territorial plans that include fire risk assessments are some of the key aspects discussed in this article. Several of the questions raised will require further research, including just how fire-dependent the ecosystems in Chile are, how the forest at the WUI can be better managed to prevent human and material damage, and how best to address the social controversy that pits the Mapuche population against the timber companies.

From Seismic Scenarios to Earthquake Risk Assessment: A Case Study for Iquique, Chile.

Science.gov (United States)

Aguirre, P.; Fortuno, C.; Martin, J. C. D. L. L.; Vasquez, J.

2015-12-01

Iquique is a strategic city and economic center in northern Chile, and is located in a large seismic gap where a megathrust earthquake and tsunami is expected. Although it was hit by a Mw 8.2 earthquake on April 1st 2014, which caused moderate damage, geophysical evidence still suggests that there is potential for a larger event, so a thorough risk assessment is key to understand the physical, social, and economic effects of such potential event, and devise appropriate mitigation plans. Hence, Iquique has been selected as a prime study case for the implementation of a risk assessment platform in Chile. Our study integrates research on three main elements of risk calculations: hazard evaluation, exposure model, and physical vulnerabilities. To characterize the hazard field, a set of synthetic seismic scenarios have been developed based on plate interlocking and the residual slip potential that results from subtracting the slip occurred during the April 1st 2014 rupture fault mechanism, obtained using InSAR+GPS inversion. Additional scenarios were developed based of the fault rupture model of the Maule 2010 Mw 8.8 earthquake and on the local plate locking models in northern Chile. These rupture models define a collection of possible realizations of earthquake geometries parameterized in terms of critical variables like slip magnitude, rise time, mean propagation velocity, directivity, and other, which are propagated to obtain a hazard map for Iquique (e.g. PGA, PGV, PDG). Furthermore, a large body of public and local data was used to construct a detailed exposure model for Iquique, including aggregated building count, demographics, essential facilities, and lifelines. This model together with the PGA maps for the April 1st 2014 earthquake are used to calibrate HAZUS outputs against observed damage, and adjust the fragility curves of physical systems according to more detailed analyses of typical Chilean building types and their structural properties, plus historical

Dynamics of a large, restless, rhyolitic magma system at Laguna del Maule, southern Andes, Chile

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Singer, Brad S.; Andersen, Nathan L.; Le Mével, Hélène; Feigl, Kurt L.; DeMets, Charles; Tikoff, Basil; Thurber, Clifford H.; Jicha, Brian R.; Cardonna, Carlos; Córdova, Loreto; Gil, Fernando; Unsworth, Martyn J.; Williams-Jones, Glyn; Miller, Craig W.; Fierstein, Judith; Hildreth, Edward; Vazquez, Jorge A.

2014-01-01

Explosive eruptions of large-volume rhyolitic magma systems are common in the geologic record and pose a major potential threat to society. Unlike other natural hazards, such as earthquakes and tsunamis, a large rhyolitic volcano may provide warning signs long before a caldera-forming eruption occurs. Yet, these signs—and what they imply about magma-crust dynamics—are not well known. This is because we have learned how these systems form, grow, and erupt mainly from the study of ash flow tuffs deposited tens to hundreds of thousands of years ago or more, or from the geophysical imaging of the unerupted portions of the reservoirs beneath the associated calderas. The Laguna del Maule Volcanic Field, Chile, includes an unusually large and recent concentration of silicic eruptions. Since 2007, the crust there has been inflating at an astonishing rate of at least 25 cm/yr. This unique opportunity to investigate the dynamics of a large rhyolitic system while magma migration, reservoir growth, and crustal deformation are actively under way is stimulating a new international collaboration. Findings thus far lead to the hypothesis that the silicic vents have tapped an extensive layer of crystal-poor, rhyolitic melt that began to form atop a magmatic mush zone that was established by ca. 20 ka with a renewed phase of rhyolite eruptions during the Holocene. Modeling of surface deformation, magnetotelluric data, and gravity changes suggest that magma is currently intruding at a depth of ~5 km. The next phase of this investigation seeks to enlarge the sets of geophysical and geochemical data and to use these observations in numerical models of system dynamics.

La fauna de caprélidos (Crustacea: Amphipoda: Caprellidea de la costa de Coquimbo, centro-norte de Chile, con una clave taxonómica para la identificación de las especies The caprellid fauna (Crustacea: Amphipoda: Caprellidea from the coast of Coquimbo, Northern-central Chile, with a taxonomic key for species identification

Directory of Open Access Journals (Sweden)

JOSÉ M. GUERRA-GARCÍA

2001-12-01

difficult due to the high degree of intra-specific morphological variability and the fact that literature and specimens from Museums are not easily located. The objective of the present study was to provide the taxonomical tools to identify the most common caprellid species from northern-central Chile. Several habitats were examined (buoys, boulders, algal/seagrass beds and six caprellid species were found: Caprellina longicollis (Nicolet, 1849, Caprella equilibra Say, 1818, C. scaura Templeton, 1836, C. verrucosa Boeck, 1871; Deutella venenosa Mayer, 1890 and Paracaprella pusilla Mayer, 1890. Caprella scaura, C. verrucosa and D. venenosa were most abundant among algae, hydrozoans and bryozoans growing on buoys. Caprella equilibra, also present on buoys, was most abundant underneath boulders in exposed rocky intertidal zones, where additionally D. venenosa and P. pusilla were found. Caprella scaura was dominant in plant beds above sandy subtidal bottom, especially among the alga Gracilaria chilensis and the seagrass Heterozostera tasmanica, where it occurred together with Caprellina longicollis. Paracaprella pusilla represents a new citation for the pacific coasts of S-America, being a new record for Chile. The species D. venenosa, which was recorded for the first time since the original description by Mayer in the year 1890, is considered an endemic species from the central coast of Chile

Tiwanaku influence and social inequality: A bioarchaeological, biogeochemical, and contextual analysis of the Larache cemetery, San Pedro de Atacama, Northern Chile.

Science.gov (United States)

Torres-Rouff, Christina; Knudson, Kelly J; Pestle, William J; Stovel, Emily M

2015-12-01

To assess the relationship between the Tiwanaku polity and the individuals buried at the Middle Horizon (∼AD500-1000) cemetery of Larache in northern Chile, a site that has been singled out as a potential elite foreign enclave. We explore this association through the skeletal remains of 48 individuals interred at the cemetery of Larache using bioarchaeological, biogeochemical, and artifactual evidence. Data from cranial modification practices, violent injury, and the mortuary assemblage are used to explore culturally constructed elements of status and identity, radiogenic strontium isotope analyses provide us with a perspective on the geographic origins of these individuals, and stable carbon and nitrogen analyses allow discussion of paleodiet and access to resources. Radiogenic strontium isotope values show the presence of multiple first generation migrants at Larache. Stable carbon and nitrogen isotope data reveal significant differences among individuals. The mortuary context reveals a standard pattern for the oases but also includes a series of unusual burials with abundant gold and few other objects. Interestingly, both local and nonlocal individuals with different head shapes had access to the differentiated burial context; however nonlocal individuals appear to be the only ones with a heavily maize-based diet. Our evidence shows that Larache served as a burial place for a diverse, yet culturally integrated and potentially elite segment of the Atacameño population, but not a foreign enclave as had been postulated. © 2015 Wiley Periodicals, Inc.

Rapid characterization of seismic sources in Chile: Contribution of the GNSS component

Science.gov (United States)

Barrientos, S. E.; Riquelme, S.; Baez, J. C., Sr.

2017-12-01

The recently created National Seismological Center (CSN) of the University of Chile was tasked to upgrade the countrýs seismic network in 2013. The upgrade included new 65 collocated accelerometer and broadband instruments together with 130 GNSS devices designed to transmit their data in real time. Forty units of the GNSS devices include the RTX option, a real time 1-Hz positioning capability at 4-cm error level. The observation system is complemented with 297 additional stand-alone strong motion instruments mainly located in basins for seismic engineering purposes. Broadband data can be accessed in real time from IRIS Data Management Service under networks C and C1. Strong motion event data can be retrieved through the CSN database (evtdb.csn.uchile.cl). A server is being established to handle GNSS data requests through an NTRIP Caster. Completion of the connectivity of the GNSS remote units to the main acquisition servers is expected to take place within several months. In addition to the 40 units providing real time positioning through the RTX option, Precise Point Positioning (PPP) algorithms are being tested on the CSN main servers to enable real time estimates every second for all GNSS remote devices. Because of the high earthquake productivity rate in Chile, the RTX system capabilities have been positively tested in two cases already, demonstrating their excellent performance: i) the main aftershock (M7.6) of the April 1, 2014, northern Chile event and ii) the April 24, 2017, (M6.9) event in central Chile. The former produced coastal horizontal static displacements of the order of 30 cm while the latter of the order of 5 cm. In addition to rapid earthquake characterization through static deformation, W-phase displacement waveform inversions are included in the fast analysis providing excellent results. These new applications and methodologies have profoundly impacted the rapid evaluation of the tsunamigenic potential of large earthquakes in the near field.

Arsenic-induced skin lesions among Atacameño people in Northern Chile despite good nutrition and centuries of exposure.

Science.gov (United States)

Smith, A H; Arroyo, A P; Mazumder, D N; Kosnett, M J; Hernandez, A L; Beeris, M; Smith, M M; Moore, L E

2000-07-01

It has been suggested that the indigenous Atacameño people in Northern Chile might be protected from the health effects of arsenic in drinking water because of many centuries of exposure. Here we report on the first intensive investigation of arsenic-induced skin lesions in this population. We selected 11 families (44 participants) from the village of Chiu Chiu, which is supplied with water containing between 750 and 800 microg/L inorganic arsenic. For comparison, 8 families (31 participants) were also selected from a village where the water contains approximately 10 microg/L inorganic arsenic. After being transported to the nearest city for blind assessment, participants were examined by four physicians with experience in studying arsenic-induced lesions. Four of the six men from the exposed village, who had been drinking the contaminated water for more than 20 years, were diagnosed with skin lesions due to arsenic, but none of the women had definite lesions. A 13-year-old girl had definite skin pigmentation changes due to arsenic, and a 19-year-old boy had both pigmentation changes and keratoses on the palms of his hands and the soles of his feet. Family interviews identified a wide range of fruits and vegetables consumed daily by the affected participants, as well as the weekly intake of red meat and chicken. However, the prevalence of skin lesions among men and children in the small population studied was similar to that reported with corresponding arsenic drinking water concentrations in both Taiwan and West Bengal, India--populations in which extensive malnutrition has been thought to increase susceptibility.

Chile Energy Policy Review 2009

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-10-22

Since 1990, Chile has been the fastest growing economy in Latin America thanks to sound economic management and integration into the global economy. Chile can also be proud of its energy policy achievements. The pioneering privatisation and liberalisation of its electricity sector in the 1980s was the foundation for a competitive energy sector, which has sustained the rapid growth of the Chilean economy over the past two decades. Nonetheless, Chile faces the continuing challenge of finding additional energy supplies to fuel economic growth. Chile has limited fossil energy resources and depends on imports to meet three-quarters of its energy needs. The country's electricity sector has faced three periods of significant stress over the past decade. The last episode took place in 2007/2008, when the loss of natural gas imports from Argentina was further exacerbated by a drought in the central system, where hydropower normally accounts for over half of electricity generation. Drawing on the experience of IEA member countries, the Review assesses Chile's major energy challenges and provides recommendations. Six main themes emerge: the successful liberalisation of the power sector in the 1980s; the essential role played by the state in ensuring energy security; the re-formulation of Chile's long-term energy policy; the proposed reorganisation of the institutional framework; greater independence for the system operators; and the need for a clear framework of regulation so that long-term investment decisions integrate social and environmental costs. This publication is essential reading for all who are interested in Chilean energy issues and in learning about the important role sound energy policy can play in developing a nation's economic and social welfare.

Vnější ekonomické vztahy Chile

OpenAIRE

Horáková, Anna

2007-01-01

Práce se zabývá vnějšími ekonomickými vztahy Chile. V první části je charakterizována ekonomika Chile. V druhé části je zmapován vývoj obchodní politiky Chile a zapojování Chile do ekonomické integrace. Poslední kapitola nejprve analyzuje vývoj obchodu Chile, ilustruje problém jednostranného zaměření chilského exportu a analyzuje obchodní vztahy s EU, USA a Čínou. Následně jsou naznačeny nové ?role? Chile ve vztahu ke světovému obchodu.

[Papillomavirus and cervical cancer in Chile].

Science.gov (United States)

O'Ryan, Miguel; Valenzuela, María Teresa

2008-11-01

Molecular, clinical and epidemiological studies have established beyond doubt that human papiloma viruses (HPV) cause cervical cancer. The virus is also associated with genital warts and other less common cancers in oropharynx, vulva, vagina and penis. Worldwide, VPH genotypes 16 and 18 are the most common high risk genotypes, detected in near 70% of women with cervical cancer. The discovery of a cause-effect relationship between several carcinogenic microorganisms and cancer open avenues for new diagnostic, treatment and prevention strategies. In this issue of Revista Médica de Chile, two papers on HPV are presented. Guzman and colleagues demonstrate that HPV can be detected in 66% to 77% of healthy male adolescents bypolymerase chain reaction and that positivity depends on the site of the penis that is sampled. These results support the role of male to female transmission of high risk HPVs in Chile and should lead to even more active educational campaigns. The second paper provides recommendations for HPV vaccine use in Chile, generated by the Immunization Advisory Committee of the Chilean Infectious Disease Society. To issue these recommendations, the Committee analyzes the epidemiological information available on HPV infection and cervical cancer in Chile, vaccine safety and effectiveness data, and describes cost-effectiveness studies. Taking into account that universal vaccination is controversial, the Committee favors vaccine use in Chile and it's incorporation into a national program. However, there is an indication that the country requires the implementation of an integrated surveillance approach including cross matching of data obtained from HPV genotype surveillance, monitoring of vaccination coverage, and surveillance of cervical cancer. The final decision of universal vaccine use in Chile should be based on a through analysis of information.ev Mid Chile

Chile: Civil-Military Relations and Democratic Consolidation

Science.gov (United States)

1998-12-01

Publishers, 1992), 41. 26 Javier Martinez and Alvaro Diaz , Chile The Great Transformation (Harrisonburg, Virginia: The Brookings Institution, 1996...the world economy, by means of technological advancements, makes it necessary to reduce 32 Javier Martinez and Alvaro Diaz , Chile the Great...disapproves the executive’s budget. There is no 60 Alicia Frohman, "Chile: External Actors and the Transition to Democracy," in Beyond Sovereignty

Pre-, Co-, and Post-Seismic Fault Slip in the Northern Chile Seismic Gap Associated with the April 1, 2014 (Mw 8.2) Pisagua Earthquake.

Science.gov (United States)

Simons, M.; Duputel, Z.; Fielding, E. J.; Galetzka, J.; Genrich, J. F.; Jiang, J.; Jolivet, R.; Kanamori, H.; Moore, A. W.; Ortega Culaciati, F. H.; Owen, S. E.; Riel, B. V.; Rivera, L. A.; Carrizo, D.; Cotte, N.; Jara, J.; Klotz, J.; Norabuena, E. O.; Ortega, I.; Socquet, A.; Samsonov, S. V.; Valderas Bermejo, M.

2014-12-01

The April 1, 2014 (Mw 8.2) Pisagua Earthquake occurred in Northern Chile, within a long recognized seismic gap in the Central Andean region that last experienced major megathrust events in 1868 and 1877. We built a continuous GPS network starting in 2005, with the ultimate goal of understanding the kinematics and dynamics of this portion of the subduction zone. Using observations from this network, as well as others in the region, combined with InSAR, seismic and tsunami observations, we obtain estimates of inter-seismic, co-seismic and initial post-seismic fault slip using an internally consistent Bayesian unregularized approach. We evaluate the extent of spatial overlap between regions of fault slip during this different time periods. Of particular interest to this event is the extent and nature of any geodetic evidence for transient slow fault slip preceding the Pisagua Earthquake mainshock. To this end, we compare daily and high rate GPS solutions, the former of which shows long period transient motion started about 15 days before the mainshock and with maximum registered amplitude of 14.2 +/- 2 [mm] at site PSGA. Contrary to published findings, we find that pre-seismic deformation seen by the GPS network can be explained as coseismic motion associated with the multiple foreshocks.

Estimación de la temperatura superficial del mar desde datos satelitales NOAA-AVHRR: validación de algoritmos aplicados a la costa norte de Chile Sea surface temperature estimation from NOAA-AVHRR satellite data: validation of algorithms applied to the northern coast of Chile

Directory of Open Access Journals (Sweden)

Juan C Parra

2011-01-01

Full Text Available Se aplicaron y compararon tres algoritmos del tipo Split-Window (SW, que permitieron estimar la temperatura superficial del mar desde datos aportados por el sensor Advanced Very High Resolution Radiometer (AVHRR, a bordo de la serie de satélites de la National Oceanic and Atmospheric Administration (NOAA. La validación de los algoritmos fue lograda por comparación con mediciones in situ de temperatura del mar provenientes de una boya hidrográfica, ubicada frente a la costa norte de Chile (21°21'S, 70°6'W; Región de Tarapacá, a 3 km de la costa aproximadamente. Los mejores resultados se obtuvieron por aplicación del algoritmo propuesto por Sobrino & Raissouni (2000. En efecto, diferencias entre la temperatura medida in situ y la estimada por SW, permitieron evidenciar una media y desviación estándar de 0,3° y 0,8°K, respectivamente.The present article applies and compares three split-window (SW algorithms, which allowed the estimation of sea surface temperature using data obtained from the Advanced Very High Resolution Radiometer (AVHRR on board the National Oceanic and Atmospheric Administration (NOAA series of satellites. The algorithms were validated by comparison with in situ measurements of sea temperature obtained from a hydrographical buoy located off the coast of northern Chile (21°21'S, 70°6'W; Tarapacá Región, approximately 3 km from the coast. The best results were obtained by the application of the algorithm proposed by Sobrino & Raissouni (2000. The mean and standard deviation of the differences between the temperatures measured in situ and those estimated by SW were 0.3° and 0.8°K, respectively.

Zahraničně obchodní politika Chile

OpenAIRE

Horáková, Anna

2009-01-01

The Diploma thesis focuses on foreign trade policy of Chile. The first part is a brief summary of socio-economic characteristics of the country. The following section deals with the individual strategies in the approach to foreign trade policy applied in Chile since independence to the present. It exams the determinants of changes in foreign trade policy of Chile and monitors changes in territorial and commodity structure of the foreign trade of Chile. In the final section assesses the curren...

Use of high-resolution satellite images for detection of geological structures related to Calerias geothermal field, Chile

Science.gov (United States)

Arellano-Baeza, A. A.; Urzua, L.

2011-12-01

Chile has enormous potential to use the geothermal resources for electric energy generation. The main geothermal fields are located in the Central Andean Volcanic Chain in the North, between the Central valley and the border with Argentina in the center, and in the fault system Liquiñe-Ofqui in the South of the country. High resolution images from the LANDSAT and ASTER satellites have been used to delineate the geological structures related to the Calerias geothermal field located at the northern end of the Southern Volcanic Zone of Chile. It was done by applying the lineament extraction technique developed by authors. These structures have been compared with the distribution of main geological structures obtained in the field. It was found that the lineament density increases in the areas of the major heat flux indicating that the lineament analysis could be a power tool for the detection of faults and joint zones associated to the geothermal fields.

Primary Medical Care in Chile

DEFF Research Database (Denmark)

Scarpaci, Joseph L.

Primary medical care in Chile: accessibility under military rule [Front Cover] [Front Matter] [Title Page] Contents Tables Figures Preface Chapter 1: Introduction Chapter 2: The Restructuring of Medical Care Financing in Chile Chapter 3: Inflation and Medical Care Accessibility Chapter 4: Help......-Seeking Behavior of the Urban Poor Chapter 5: Spatial Organization and Medical Care Accessibility Chapter 6: Conclusion...

Copper Bioleaching in Chile

OpenAIRE

Juan Carlos Gentina; Fernando Acevedo

2016-01-01

Chile has a great tradition of producing and exporting copper. Over the last several decades, it has become the first producer on an international level. Its copper reserves are also the most important on the planet. However, after years of mineral exploitation, the ease of extracting copper oxides and ore copper content has diminished. To keep the production level high, the introduction of new technologies has become necessary. One that has been successful is bioleaching. Chile had the first...

Andes hantavirus variant in rodents, southern Amazon Basin, Peru.

Science.gov (United States)

Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M; Salmon-Mulanovich, Gabriela; Guezala, M Claudia; Albujar, Christian; Mendoza, A Patricia; Tinoco, Yeny O; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah; Nichol, Stuart T; Hirschberg, David L; Lipkin, W Ian; Bausch, Daniel G; Montgomery, Joel M

2014-02-01

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

Andes Hantavirus Variant in Rodents, Southern Amazon Basin, Peru

OpenAIRE

Razuri, Hugo; Tokarz, Rafal; Ghersi, Bruno M.; Salmon-Mulanovich, Gabriela; Guezala, M. Claudia; Albujar, Christian; Mendoza, A. Patricia; Tinoco, Yeny O.; Cruz, Christopher; Silva, Maria; Vasquez, Alicia; Pacheco, Víctor; Ströher, Ute; Guerrero, Lisa Wiggleton; Cannon, Deborah

2014-01-01

We investigated hantaviruses in rodents in the southern Amazon Basin of Peru and identified an Andes virus variant from Neacomys spinosus mice. This finding extends the known range of this virus in South America and the range of recognized hantaviruses in Peru. Further studies of the epizoology of hantaviruses in this region are warranted.

Altitudinal gradients, midwinter melt, and wind effects on snow accumulation in semiarid midlatitude Andes under La Niña conditions

Science.gov (United States)

Ayala, A.; McPhee, J.; Vargas, X.

2014-04-01

The Andes Cordillera remains a sparsely monitored and studied snow hydrology environment in comparison to similar mountain ranges in the Northern Hemisphere. In order to uncover some of the key processes driving snow water equivalent (SWE) spatial variability, we present and analyze a distributed SWE data set, sampled at the end of accumulation season 2011. Three representative catchments across the region were monitored, obtaining measurements in an elevation range spanning 2000 to 3900 m asl and from 32.4° to 34.0°S in latitude. Climatic conditions during this season corresponded to a moderate La Niña phenomenon, which is generally correlated with lower-than normal accumulation. Collected measurements can be described at the regional and watershed extents by altitudinal gradients that imply an increase by a factor of two in snow depth between 2200 and 3000 m asl, though with significant variability at the upper sites. In these upper sites, we found north-facing, wind-sheltered slopes showing 25% less average SWE values than south-facing, wind-exposed ones. This suggests that under these conditions, solar radiation dominated wind transport effects in controlling end-of-winter variability. Nevertheless, we found clusters of snow depth measurements above 3000 m asl that can be explained by wind exposure differences. This is the first documented snow depth data set of this spatial extent for this region, and it is framed within an ongoing research effort aimed at improving understanding and modeling of snow hydrology in the extratropical Andes Cordillera.

Parasites of the Green-backed Firecrown (Sephanoides sephaniodes in Chile Parásitos del picaflor chico (Sephanoides sephaniodes en Chile

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Daniel González-Acuña

2011-12-01

Full Text Available Gastrointestinal and external parasites from 12 Green-backed Firecrown (Sephanoides sephaniodes were collected between January 2004 and December 2008 from the Biobío Region south-central Chile and Santiago (central Chile. Helminths collected included 1 trematode species (Mosesia sp. and 1 cestode species (Hymenolepis trinidadensis. The mite Proctophyllodes huitzilopchtlii was the only ectoparasite species found. All these parasites represent new records for Chile and the first parasites reported for this host species.Se recolectaron parásitos internos (gastrointestinales y externos de 12 picaflores (Sephanoides sephaniodes entre enero del 2004 y diciembre del 2008, de la región del Biobío en el centro-sur de Chile y en Santiago, en la región central de Chile. Los helmintos recolectados incluyeron 1 especie de trematodo (Mosesia sp. y 1 de cestodo (Hymenolepis trinidadensis. Únicamente se encontró 1 especie de ectoparásito, el ácaro Proctophyllodes huitzilopchtlii. Todos los parásitos mencionados representan nuevos registros para Chile y se registran por primera vez para este hospedero.

Diversidad taxonómica y denso-actividad de solífugos (Arachnida: Solifugae asociados a un ecosistema desértico costero del centro norte de Chile Taxonomic diversity and density-activity of solpugids (Arachnida: Solifugae in a coastal desert ecosystem in the northern centre of Chile

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Daniel E. Valdivia

2008-06-01

Full Text Available En Chile, el orden Solifugae está representado por 14 especies agrupadas en 10 géneros, distribuidos en las tres familias descritas en Sudamérica: Ammotrechidae, Mummuciidae y Daesiidae. En el presente trabajo se documenta la composición genérica y/o específica de solífugos asociados a un ecosistema desértico costero del centro norte de Chile, y se muestran las variaciones de su denso-actividad. El estudio se realizó en el sector costero de Punta de Choros (29°21'S, 71°10'O; 17 msnm, durante los meses de junio, agosto, octubre y noviembre de 2005. Entre los 249 ejemplares capturados, se reconoció la presencia de tres familias, cuatro géneros y cinco especies. Éstas fueron Procleobis sp., Sedna pirata Muma (Ammotrechidae, Mummucia sp., Mummucia variegata (Gervais (Mummuciidae y Ammotrechelis goetschi Roewer (Daesiidae. La mayor denso-actividad de solífugos se registró en los meses de octubre, 5 especies (ca 30 % del total capturado; y noviembre, 3 especies (ca 41 % del total capturado. Mientras que algunas especies se mostraron activas durante todo el período de estudio (e.g., Ammotrechelis goetschi, otras presentaron actividad parcial. Por ejemplo, Mummucia variegata manifestó actividad entre agosto y noviembre; Sedna pirata entre octubre y noviembre y tanto Procleobis sp. como Mummucia sp. estuvieron activas sólo en octubre. La diversidad y la denso-actividad de Solifugae estarían determinadas por factores biológicos y ecológicos.In Chile the order Solifugae is represented by 14 species arranged in 10 genera distributed among the three families described for South America: Ammotrechidae, Mummuciidae and Daesiidae. The present work documents the taxonomic composition of solpugids in a desert coastal ecosystem of the northern centre of Chile and describes variation in their density-activity. The study was carried out in the coastal sector of Punta de Choros (29°21'S, 71°10'W; 17 masl during June, August, October and

Correlation of Early Tertiary Terrestrial Deposits of the Amaga Basin, Cauca Depression, Colombian Andes

Science.gov (United States)

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

2001-05-01

The Amaga Formation of the Amaga Basin preserves early Tertiary terrestrial deposits of many facies: channel, crevasse splay, paludal, flood plain, point bar, etc. These deposits lie between two major strike-slip fault zones, the Cauca and the Romeral in the Cauca Valley of the northern Andes of Colombia. Coal deposits characterize the lower part of the stratigraphic section; fine to medium clastic sediments otherwise dominate the sections. Within the basin, correlation between sections is difficult because various discontinuities interrupt the continuity of the strata. These include Tertiary intrusives, folding and faulting. Rapid lateral facies changes further complicate the correlations. Detailed studies on five stratigraphic sections are underway. Multiple methods of correlating sections are being used, including fluvial sequence stratigraphy in outcrops, architectural facies analysis, heavy mineral separates, grain-size and grain-ratio variations, paleocurrent directions, and magnetic property variations. Distinctive regional variations in magnetic anisotropic susceptibility indicate areas in which tectonic effects overprint sedimentary fabrics. The presence of secondary hematite and siderite is related to that overprinting. A major compositional break (identified by grain-ratio variations) has been found in the middle of the section. The integrated correlation results are summarized.

Development of methods for evaluating options for improving air quality in Santiago, Chile and its environs. Final report

Energy Technology Data Exchange (ETDEWEB)

Williams, M.D.; Brown, M.J.

1993-10-01

Santiago, Chile has a serious air pollution problem. Aerosols reach very high levels and ozone exceeds US ambient standards on over 100 days a year. Chileans are very concerned about the poor air quality of Santiago and the effect of emissions from their copper smelters both near Santiago and at other sites. Officials from both the Santiago metropolitan air quality commission (La Comision Especial de Descontaminacion de le Region Metropolitana) and a government owned copper development company (La Empress Nacional de Mineria (ENAMI)) have asked for assistance to deal with the air quality problems in the city and associated with smelter emissions. This report describes the first steps in that effort. Santiago lies in a valley between a small coastal range to the west and the towering Andes to the cast. Air motion is greatly affected by the major topographical features which include the Pacific Ocean, the coastal range, and the Andes. In this first year of work the authors concentrated on gathering information on the meteorology, topography, and air quality of the metropolitan region. They examined two smelter sites and applied models to them to help their understanding and to provide assistance to ENAMI. One smelter, Ventanas, was located on the Pacific coast to the northwest of Santiago, while the other, Paipote, was located several hundred kilometers to the north. The Ventanas emissions may potentially affect Santiago air quality. Several advantages of working with the smelters in the first phase of the project are: (1) there is more monitoring in the vicinity of the smelters, (2) the development of a useful emission inventory is easier, (3) they pose a simpler problem of immediate interest whose resolution will provide an early benefit to the Chilean colleagues, and (4) the authors gain important experience as they prepare to delve deeper into Santiago`s air pollution problems.

Physical, chemical and mineralogical evolution of the Tolhuaca geothermal system, southern Andes, Chile: Insights into the interplay between hydrothermal alteration and brittle deformation

Science.gov (United States)

Sanchez-Alfaro, Pablo; Reich, Martin; Arancibia, Gloria; Pérez-Flores, Pamela; Cembrano, José; Driesner, Thomas; Lizama, Martin; Rowland, Julie; Morata, Diego; Heinrich, Christoph A.; Tardani, Daniele; Campos, Eduardo

2016-09-01

In this study, we unravel the physical, chemical and mineralogical evolution of the active Tolhuaca geothermal system in the Andes of southern Chile. We used temperature measurements in the deep wells and geochemical analyses of borehole fluid samples to constrain present-day fluid conditions. In addition, we reconstructed the paleo-fluid temperatures and chemistry from microthermometry and LA-ICP-MS analysis of fluid inclusions taken from well-constrained parageneses in vein samples retrieved from a 1000 m borehole core. Based on core logging, mineralogical observations and fluid inclusions data we identify four stages (S1-S4) of progressive hydrothermal alteration. An early heating event (S1) was followed by the formation of a clay-rich cap in the upper zone (propylitic alteration assemblage at greater depth (S2). Boiling, flashing and brecciation occurred later (S3), followed by a final phase of fluid mixing and boiling (S4). The evolution of hydrothermal alteration at Tolhuaca has produced a mineralogical, hydrological and structural vertical segmentation of the system through the development of a low-permeability, low-cohesion clay-rich cap at shallow depth. The quantitative chemical analyses of fluid inclusions and borehole fluids reveal a significant change in chemical conditions during the evolution of Tolhuaca. Whereas borehole (present-day) fluids are rich in Au, B and As, but Cu-poor (B/Na 100.5, As/Na 10- 1.1, Cu/Na 10- 4.2), the paleofluids trapped in fluid inclusions are Cu-rich but poor in B and As (B/Na 10- 1, As/Na 10- 2.5, Cu/Na 10- 2.5 in average). We interpret the fluctuations in fluid chemistry at Tolhuaca as the result of transient supply of metal-rich, magmatically derived fluids where As, Au and Cu are geochemically decoupled. Since these fluctuating physical and chemical conditions at the reservoir produced a mineralogical vertical segmentation of the system that affects the mechanical and hydrological properties of host rock, we explored

Chile; Staff Report for the 2003 Article IV Consultation

OpenAIRE

International Monetary Fund

2003-01-01

Chile has successfully resisted contagion from neighboring countries difficulties. Chile's inflation targeting framework has successfully anchored inflation expectations and increased the economy's resilience to external shocks while maintaining price stability. The floating exchange rate regime is an essential part of the macroeconomic policy framework and continues to serve Chile well. The interest in recapitalizing the central bank is welcomed. Executive Directors commend Chile for the tra...

A new species of Trechisibus from Peruvian Andes (Coleoptera: Carabidae, Trechinae

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Pedro Delgado

2016-06-01

Full Text Available In this work the new species Trechisibus (s. str. delestali sp. n., is described from the southern Peruvian Andes. The morphological differences with the geographically closest species of the subgenus are also presented and discussed.

Decision analysis applied to the fishery of the sea snail Concholepas concholepas from central northern coast of Chile

OpenAIRE

Tam, J.; Palma, W.; Riofrio, M.; Aracena, O.; Lepez, M.I.

1996-01-01

Formal decision analysis was applied to the management of loco (Concholepas concholepas, Fam. Muricidae) in Chile, 29-35 degrees S. Four interested groups were considered "Fishers", "Scientists", "Buyers" and the "State", along with three fishing effort levels and four subobjectives. The method was found to encourage the emergence of a consensus (here: halving of effort), and is recommended for use in other fisheries.

The helminth fauna of CHIle: IV. Nematodes of the genera Anisakis Dujardin, 1845 AND Phocanema Myers, 1954 in relation with gastric ulcers in a South American Sea Lion, Otaria byronia.

Science.gov (United States)

Cattan, P E; Babero, B B; Torres, D

1976-10-01

A gastric ulcer was diagnosed in a South American Sea Lion, Otario byronia, captured along the northern coast of Chile. Species of Anisakis and Phocanema were found to be associated with the lesions. A discussion of the histopathologic damage observed is presented, along with probable etiology of the ulcer.

Where Do Mexico and Chile Stand on Inclusive Education? Short Title: Inclusion in Mexico and Chile

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García-Cedillo, Ismael; Romero-Contreras, Silvia; Ramos-Abadie, Liliana

2015-01-01

This paper discusses the background, current situation and challenges of educational integration and inclusive education in Mexico and Chile. These countries obtained similar low results on the academic achievement of their students (Mexico last and Chile second last) among OECD countries; and above average scores, among Latin-American countries.…

Radioactive wastes management development in Chile

International Nuclear Information System (INIS)

Mir, S.A.; Cruz, P.F.; Rivera, J.D.; Jorquera, O.H.

1994-01-01

A Facility for immobilizing and conditioning of radioactive wastes generated in Chile, has recently started in operation. It is a Radioactive Wastes Treatment Plant, RWTP, whose owner is Comision Chilena de Energia Nuclear, CCHEN. A Storgement Building of Conditioned Wastes accomplishes the facility for medium and low level activity wastes. The Project has been carried with participation of chilean professionals at CCHEN and Technical Assistance of International Atomic Energy Agency, IAEA. Processes developed are volume reduction by compaction; immobilization by cementation and conditioning. Equipment has been selected to process radioactive wastes into a 200 liters drum, in which wastes are definitively conditioned, avoiding exposition and contamination risks. The Plant has capacity to treat low and medium activity radioactive wastes produced in Chile due to Reactor Experimental No. 1 operation, and annex Laboratories in Nuclear Research Centers, as also those produced by users of nuclear techniques in Industries, Hospitals, Research Centers and Universities, in the whole country. With the infrastructure developed in Chile, a centralization of Radioactive Wastes Management activities is achieved. A data base system helps to control and register radioactive wastes arising in Chile. Generation of radioactive wastes in Chile, has found solution for the present production and that of near future

The biomethane potential in Chile

International Nuclear Information System (INIS)

Seiffert, M.; Kaltschmitt, M.; Miranda, J.A.

2009-01-01

Within the last decade natural gas gained considerable importance in Chile. The contribution of natural gas within the energy system will increase in the future by predicted 3.6% annually until the year 2015. Due to limited resources within its own country, the energy system of Chile depends on natural gas imports preferential from Argentina. Therefore, the aim of several stakeholders from policy and industry is to reduce the share of imported primary energy within the overall energy system. In order to reach this goal, the use of domestic resources and particularly the utilisation of biomass as one of the most important renewable sources of energy in Chile could play an important role. Against this background, the goal of this paper is the analysis of the technical potentials of biomethane as a substitute for natural gas. For the production of biomethane the anaerobic or bio-chemical (i.e. Biogas) as well as the thermo-chemical conversion pathways (i.e. Bio-SNG) are considered. The results of this analysis show that biomass converted to biomethane is a promising energy provision option for Chile and it contributes to the reduction of greenhouse gas emissions

Retail Bank Interest Rate Pass-Through; Is Chile Atypical?

OpenAIRE

Alessandro Rebucci; Marco A Espinosa-Vega

2003-01-01

This paper investigates empirically the pass-through of money market interest rates to retail banking interest rates in Chile, the United States, Canada, Australia, New Zealand, and five European countries. Overall, Chile's pass-through does not appear atypical. Based on a standard error-correction model, we find that, as in most countries considered, Chile's measured pass-through is incomplete. But Chile's pass-through is also faster than in many other countries considered and is comparable ...

Tectonostratigraphic reconstruction Cretaceous volcano-sedimentary in the northwestern Andes: from extensional tectonics to arc accretion.

Science.gov (United States)

Zapata, S.; Patino, A. M.; Cardona, A.; Mejia, D.; Leon, S.; Jaramillo, J. S.; Valencia, V.; Parra, M.; Hincapie, S.

2014-12-01

Active continental margins characterized by continuous convergence experienced overimposed tectonic configurations that allowed the formation of volcanic arcs, back arc basins, transtensional divergent tectonics or the accretion of exotic volcanic terranes. Such record, particularly the extensional phases, can be partially destroyed and obscure by multiple deformational events, the accretion of exotic terranes and strike slip fragmentation along the margin. The tectonic evolution of the northern Andes during the Mesozoic is the result of post Pangea extension followed by the installation of a long-lived Jurassic volcanic arc (209 - 136 ma) that apparently stops between 136 Ma and 110 Ma. The Quebradagrande Complex has been define as a single Lower Cretaceous volcano-sedimentary unit exposed in the western flank of the Central Cordillera of the Colombian Andes that growth after the Late Jurassic to Early Cretaceous magmatic hiatus. The origin of this unit have been related either to an oceanic volcanic arc or a marginal basin environment. The existence of such contrasting models reflect the regional perspective followed in published studies and the paucity of detail analysis of the volcano-sedimentary sequences.We integrate multiple approaches including structural mapping, stratigraphy, geochemistry, U-Pb provenance and geochronology to improve the understanding of this unit and track the earlier phases of accumulation that are mask on the overimposed tectonic history. Our preliminary results suggest the existence of different volcano-sedimentary units that accumulated between 100 Ma and 82 Ma.The older Lower Cretaceous sequences was deposited over Triassic metamorphic continental crust and include a upward basin deepening record characterized by thick fan delta conglomerates, followed by distal turbidites and a syn-sedimentary volcanic record at 100 ma. The other sequence include a 85 - 82 Ma fringing arc that was also formed close to the continental margin or

Socioeconomic determinants of disability in Chile.

Science.gov (United States)

Zitko Melo, Pedro; Cabieses Valdes, Báltica

2011-10-01

Disability is a worldwide public health priority. A shift from a biomedical perspective of dysfunction to a broader social understanding of disability has been proposed. Among many different social factors described in the past, socioeconomic position remains as a key multidimensional determinant of health. The study goal was to analyze the relationship between disability and different domains of socioeconomic position in Chile. Cross-sectional analysis of an anonymized population-based survey conducted in Chile in 2006. Any disability (dichotomous variable) and 6 different types of disability were analyzed on the bases of their relationship with income quintiles, occupational status, educational level, and material living standards (quality of the housing, overcrowding rate and sanitary conditions). Confounding and interaction effects were explored using R statistical program. Income, education, occupation, and material measures of socioeconomic position, along with some sociodemographic characteristics of the population, were independently associated with the chance of being disabled in Chile. Interestingly, classic measures of socioeconomic position (income, education, and occupation) were consistently associated with any disability in Chile, whereas material living conditions were partially confounded by these classic measures. In addition to this, each type of disability showed a particular pattern of related social determinants, which also varied by age group. This study contributed to the understanding of disability in Chile and how different domains of socioeconomic position might be associated with this prevalent condition. Disability remains a complex multidimensional public health problem in Chile that requires the inclusion of a wide range of risk factors, of which socioeconomic position is particularly relevant. Copyright © 2011 Elsevier Inc. All rights reserved.

Environmental lithium exposure in the north of Chile - Tissue exposure indices

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Leonardo T. Figueroa

2013-09-01

Full Text Available Background: northern Chile has the highest levels of lithium in surface waters in the world which is reflected in very high lithium levels in the plants and animals that depend on these water systems and consequently in the indigenous population.Methods: the lithium tissue burdens in populations from two valleys in the extreme north of Chile have been studied. The bulk of this report is based on analyses of lithium levels in urine, hair, and breast milk in the population of several villages. Data on serum levels, some of which had been previously published, are included for the sake of completeness. Since this paper reports studies by several groups of workers samples were analysed by a variety of methods. These include atomic emission, atomic absorption, other photospectroscopic techniques and mass spectroscopy.Results: in all samples studied the average lithium level (5.3 ppm was found to be significantly elevated compared to levels reported in the literature and measured in this study for people not exposed to high levels in water and food (0.009-0.228 ppm.Conclusions: the people studied represent a unique longitudinal cohort. The work should provide important insights into the potential neuroprotective effects of lithium also help us set guidelines to assess the risks from high dose environmental exposure.

Boundary Condition Effects on Hillslope Form and Soil Development Along a Climatic Gradient From Semiarid to Hyperarid in Northern Chile

Science.gov (United States)

Owen, J. J.; Dietrich, W. E.; Nishiizumi, K.; Bellugi, D.; Amundson, R.

2008-12-01

Modeling the development of hillslopes using mass balance equations has generated many testable hypotheses related to morphology, process rates, and soil properties, however it is only relatively recently that techniques for constraining these models (such as cosmogenic radionuclides) have become commonplace. As such, many hypotheses related to the effects of boundary conditions or climate on process rates and soil properties have been left untested. We selected pairs of hillslopes along a precipitation gradient in northern Chile (24°-30° S) which were either bounded by actively eroding (bedrock-bedded) channels or by stable or aggradational landforms (pediments, colluvial aprons, valley bottoms). For each hillslope we measured soil properties, atmospheric deposition rates, and bedrock denudation rates. We observe significant changes in soil properties with climate: there is a shift from thick, weathered soils in the semiarid south, to the near absence of soil in the arid middle, to salt-rich soils in the hyperarid north. Coincident with these are dramatic changes in the types and rates of processes acting on the soils. We found relatively quick, biotically-driven soil formation and transport in the south, and very slow, salt-driven processes in the north. Additionally, we observe systematic differences between hillslopes of different boundary condition within the same climate zone, such as thicker soils, gentler slopes, and slower erosion rates on hillslopes with a non-eroding boundary versus an eroding boundary. These support general predictions based on hillslope soil mass balance equations and geomorphic transport laws. Using parameters derived from our field data, we attempt to use a mass balance model of hillslope development to explore the effect of changing boundary conditions and/or shifting climate.

[Beginning of the Microbiology education in Chile: formation centers].

Science.gov (United States)

Osorio, Carlos

2015-08-01

The first Chair of Microbiology in Chile was created in the School of Medicine of the Cañadilla at the University of Chile in 1892. Dr. Alejandro del Río Soto Aguilar was its first Professor. For almost three decades it was the only educational center for microbiologists in Chile. Among them were the first Professors of the new School of Medicine of the Catholic University of Chile and of the University of Concepción.

El proceso emprendedor en Chile

OpenAIRE

José Miguel Benavente

2004-01-01

Este estudio analiza los factores que afectan en forma positiva y negativa el proceso de creación de emprendimientos dinámicos en Chile. Se basa en una encuesta a 200 empresas jóvenes, la cual es parte de una muestra de casi 2000 empresas de América Latina. El presente estudio se enfoca básicamente en el segmento de nuevos emprendimientos existentes en Chile.

Analysis of La Dehesa paleo-landslide. Central Pre-Andes of Argentina

Science.gov (United States)

Tapia Baldis, Carla; Rothis, Luis Martín; Perucca, Laura; Esper Angillieri, María; Vargas, Horacio; Ponce, David; Allis, Carlos

2018-04-01

The main objective of this paper is to consider the influence of Quaternary faults as likely triggering factor for rockslides occurrence in the Central Pre-Andes, a region with intense shallow seismic activity. A rockslide deposit was selected as study case, placed in the western flank of La Dehesa and Talacasto (DT) range (31°3‧37″ S and 68°46‧ 8″ W). Applied methodology includes the characterization of main discontinuities, reconstruction of the topography using a high-resolution digital elevation model, safety factor calculation along the sliding surface and, Newmark displacements estimation for three different hypothetical seismic scenarios, recreated from existing neotectonic local information. Equilibrium-limit method's results confirm that study case, La Dehesa rockslide (LDR), had a stable and safe slope's configuration under static conditions. However, a seismic horizontal coefficient between 0.2 and 0.3 decreases safety factor below the safety threshold. Newmark's displacements for different seismic reconstructed scenarios varies between 4.1 and 15.9 cm, values that agreed with a coherent failure process, likely triggered by Pleistocene to Holocene seismogenic sources in Central Pre-Andes. LDR trigger could be assigned mainly to an earthquake related to La Dehesa Quaternary fault (LDF) activity; however, similar movements produced by neighboring faults should not be discarded. LDR triggering related to climatic conditions is despised. Finally, the methodology presented in this work is easy to reproduce and may be applied to other rockslides located in the mountainous areas of the Central Pre-Andes of Argentina.

Intra-arc Seismicity: Geometry and Kinematic Constraints of Active Faulting along Northern Liquiñe-Ofqui and Andean Transverse Fault Systems [38º and 40ºS, Southern Andes

Science.gov (United States)

Sielfeld, G.; Lange, D.; Cembrano, J. M.

2017-12-01

Intra-arc crustal seismicity documents the schizosphere tectonic state along active magmatic arcs. At oblique-convergent margins, a significant portion of bulk transpressional deformation is accommodated in intra-arc regions, as a consequence of stress and strain partitioning. Simultaneously, crustal fluid migration mechanisms may be controlled by the geometry and kinematics of crustal high strain domains. In such domains shallow earthquakes have been associated with either margin-parallel strike-slip faults or to volcano-tectonic activity. However, very little is known on the nature and kinematics of Southern Andes intra-arc crustal seismicity and its relation with crustal faults. Here we present results of a passive seismicity study based on 16 months of data collected from 33 seismometers deployed along the intra-arc region of Southern Andes between 38˚S and 40˚S. This region is characterized by a long-lived interplay among margin-parallel strike-slip faults (Liquiñe-Ofqui Fault System, LOFS), second order Andean-transverse-faults (ATF), volcanism and hydrothermal activity. Seismic signals recorded by our network document small magnitude (0.2P and 2,796 S phase arrival times have been located with NonLinLoc. First arrival polarities and amplitude ratios of well-constrained events, were used for focal mechanism inversion. Local seismicity occurs at shallow levels down to depth of ca. 16 km, associated either with stratovolcanoes or to master, N10˚E, and subsidiary, NE to ENE, striking branches of the LOFS. Strike-slip focal mechanisms are consistent with the long-term kinematics documented by field structural-geology studies. Unexpected, well-defined NW-SE elongated clusters are also reported. In particular, a 72-hour-long, N60˚W-oriented seismicity swarm took place at Caburgua Lake area, describing a ca. 36x12x1km3 faulting crustal volume. Results imply a unique snapshot on shallow crustal tectonics, contributing to the understanding of faulting processes

Crustal contributions to arc magmatism in the Andes of Central Chile

Science.gov (United States)

Hildreth, W.; Moorbath, S.

1988-01-01

Fifteen andesite-dacite stratovolcanoes on the volcanic front of a single segment of the Andean arc show along-arc changes in isotopic and elemental ratios that demonstrate large crustal contributions to magma genesis. All 15 centers lie 90 km above the Benioff zone and 280??20 km from the trench axis. Rate and geometry of subduction and composition and age of subducted sediments and seafloor are nearly constant along the segment. Nonetheless, from S to N along the volcanic front (at 57.5% SiO2) K2O rises from 1.1 to 2.4 wt %, Ba from 300 to 600 ppm, and Ce from 25 to 50 ppm, whereas FeO*/MgO declines from >2.5 to 1.4. Ce/Yb and Hf/Lu triple northward, in part reflecting suppression of HREE enrichment by deep-crustal garnet. Rb, Cs, Th, and U contents all rise markedly from S to N, but Rb/Cs values double northward - opposite to prediction were the regional alkali enrichment controlled by sediment subduction. K/Rb drops steeply and scatters greatly within many (biotite-free) andesitic suites. Wide diversity in Zr/Hf, Zr/Rb, Ba/Ta, and Ba/La within and among neighboring suites (which lack zircon and alkali feldspar) largely reflects local variability of intracrustal (not slab or mantle) contributions. Pb-isotope data define a limited range that straddles the Stacey-Kramers line, is bracketed by values of local basement rocks, in part plots above the field of Nazca plate sediment, and shows no indication of a steep (mantle+sedimentary) Pb mixing trend. 87Sr/86Sr values rise northward from 0.7036 to 0.7057, and 143Nd/144Nd values drop from 0.5129 to 0.5125. A northward climb in basal elevation of volcanic-front edifices from 1350 m to 4500 m elevation coincides with a Bougueranomaly gradient from -95 to -295 mgal, interpreted to indicate thickening of the crust from 30-35 km to 50-60 km. Complementary to the thickening crust, the mantle wedge beneath the front thins northward from about 60 km to 30-40 km (as slab depth is constant). The thick northern crust contains

Influencia del fenómeno ENSO sobre la precipitación nival en el sector andino de Chile central durante el invierno

Directory of Open Access Journals (Sweden)

1998-01-01

Full Text Available INFLUENCE DU PHÉNOMÈNE ENSO SUR LES PRÉCIPITATIONS NEIGEUSES DANS LE CENTRE DU CHILI ANDIN AU COURS DE L’HIVER AUSTRAL. On analyse l’influence du phénomène El Niño/Oscillation du Sud (ENSO sur les précipitations nivales dans les Andes du Chili central au cours de l’hiver. Pour cela, on a utilisé l’information obtenue sur des sites spécifiques (routes de neige situées entre 30° et 38° S et les anomalies de Température de Surface de la Mer (TSM du bloc Niño 3, comme indicateur de l’importance des événements chauds ou froids dans le Pacifique équatorial central. Au nord de 35°S, l’accumulation de neige tend à être supérieure à la normale quand l’anomalie moyenne de TSM dépasse +1°C au cours de la période mai-août. Dans ce même secteur, on enregistre une précipitation inférieure à la normale les hivers caractérisés par une anomalie de TSM inférieure à -0,5°C. Dans la zone située au sud de 35° S, l’influence du phénomène ENSO sur l’accumulation de neige n’est plus significative. Se analiza la influencia del fenómeno El Niño/Oscilación del Sur (ENSO sobre la precipitación nival en los Andes de Chile central durante el invierno. Para esto, se utiliza información de rutas de nieve localizadas entre 30° y 38° S, y de anomalías de temperatura superficial del mar (TSM en la región Niño 3 como un indicador de la magnitud de los eventos cálidos y fríos en el Pacífico ecuatorial central. En la región al norte de 35° S, la acumulación de nieve durante el invierno tiende a ser superior a lo normal cuando la magnitud de la anomalía media de TSM en el periodo mayo-agosto supera +1,0° C. En este mismo sector se verifica que durante los inviernos caracterizados por una anomalía de TSM inferior a -0,5° C, suele registrarse una precipitación nival inferior a lo normal. En el sector al sur de los 35° S, la influencia del fenómeno ENSO sobre la acumulación de nieve durante el invierno no es

Snow cover dynamics in Andean watersheds of Chile (32.0-39.5° S) during the years 2000-2016

Science.gov (United States)

Stehr, Alejandra; Aguayo, Mauricio

2017-10-01

Andean watersheds present important snowfall accumulation mainly during the winter, which melts during the spring and part of the summer. The effect of snowmelt on the water balance can be critical to sustain agriculture activities, hydropower generation, urban water supplies and wildlife. In Chile, 25 % of the territory between the region of Valparaiso and Araucanía comprises areas where snow precipitation occurs. As in many other difficult-to-access regions of the world, there is a lack of hydrological data of the Chilean Andes related to discharge, snow courses, and snow depths, which complicates the analysis of important hydrological processes (e.g. water availability). Remote sensing provides a promising opportunity to enhance the assessment and monitoring of the spatial and temporal variability of snow characteristics, such as the snow cover area (SCA) and snow cover dynamic (SCD). With regards to the foregoing questions, the objective of the study is to evaluate the spatiotemporal dynamics of the SCA at five watersheds (Aconcagua, Rapel, Maule, Biobío and Toltén) located in the Chilean Andes, between latitude 32.0 and 39.5° S, and to analyse its relationship with the precipitation regime/pattern and El Niño-Southern Oscillation (ENSO) events. Those watersheds were chosen because of their importance in terms of their number of inhabitants, and economic activities depending on water resources. The SCA area was obtained from MOD10A2 for the period 2000-2016, and the SCD was analysed through a number of statistical tests to explore observed trends. In order to verify the SCA for trend analysis, a validation of the MOD10A2 product was done, consisting of the comparison of snow presence predicted by MODIS with ground observations. Results indicate that there is an overall agreement of 81 to 98 % between SCA determined from ground observations and MOD10A2, showing that the MODIS snow product can be taken as a feasible remote sensing tool for SCA estimation in

Aspects of Integration and Adaptation of Croatian Immigrants in Chile

Directory of Open Access Journals (Sweden)

Marina Perić

2004-09-01

Full Text Available The emigration of Croats to Chile was a part of transoceanic migration that occurred at the end of the 19th and at the beginning of the 20th century. Croatia at the time was within the Austro-Hungarian Monarchy. The most important area of emigration was Dalmatia, especially the island of Brač. Emigration went on without organisation, with no emigration policy or legislative framework. The main routes of emigration to Chile were to its northern parts (Antofagasta and Tarapaca and southern parts (the province Magallanes. In the new social milieu, in the immigration country – i.e. Chile, Croatian immigrants passed through various processes of integration and adaptation. The openness of Chilean society and politics to cultural pluralism gave them the opportunity to freely express themselves and their ethnicity. On the other hand, Chilean laws did not permit dual citizenship, and thus the children of the immigrants automatically became Chileans. Croatian immigrants at first nurtured a mechanical type of solidarity, since their migration was a chain development and they lived in groups of relatives and friends. After they assured for themselves the material necessities of life, they began to establish societies and were recognized from the outside as an immigrant group, distinct from other such groups. With time social stratification developed among them. They lived in communion with many other immigrant groups. They were attracted to all Slavic immigrant groups and they also have good relations with Chileans. Mixed marriages, mostly with Chileans, quickened the process of assimilation and brought about the almost total disappearance of the Croatian language. This paper is based on research, until the present, made by Croatian and Chilean authors into the historical sources and newspaper articles analysing the process of integration of immigrants on three social levels: within Chilean society, within their own immigrant groups and in regard to

Holocene tephra-fall deposits of southern and austral Andes volcanic zones (33-54oS): eruption recurrence

International Nuclear Information System (INIS)

Naranjo, J.A.; Polanco, E.; Lara, L; Moreno, H; Stern, C.R

2001-01-01

Radiometric 14 C dating is a very useful tool to study the chronostratigraphy of pyroclastic deposits. In addition, 14 C ages are essential parameters for the estimation of the recurrence time of the explosive volcanic activity. The origin, distribution and relative age of mappable Holocene tephra-fall deposits of the Southern Andes Volcanic Zone (SVZ) and Austral Andes Volcanic Zone (AVZ) from 33 o S-54 o S, were studied and their recurrence period is analysed (au)

The current situation for gastric cancer in Chile.

Science.gov (United States)

Caglevic, Christian; Silva, Shirley; Mahave, Mauricio; Rolfo, Christian; Gallardo, Jorge

2016-01-01

Gastric cancer is a neoplasm with a high incidence and mortality rate in Chile where more than 3000 people die every year from this type of cancer. This study shows the clinical and epidemiological considerations of this disease, information about translational research on this pathology in Chile, the contribution of Chilean doctors to the development of gastric cancer management awareness and the general situation of gastric cancer in Chile.

Biogeografía marina de Chile continental Marine biogeography of continental Chile

Directory of Open Access Journals (Sweden)

PATRICIO A. CAMUS

2001-09-01

literature review on the marine biogeography of Chile and related subjects, with the following objectives: (a to summarize the oceanographic, climatic and geomorphologic characteristics of the Chilean continental coast; (b to discuss 27 biogeographic classifications published for the Chilean coast, analyzing both the procedures and criteria used by their authors, along with their main conclusions and agreements; (c to assess the vicariant and dispersal processes associated with the displacement and modification of the regional biotas, regarding the available antecedentes on the prevailing conditions and main events during the Tertiary and Quaternary periods; and (d to propose a scenario of biogeographic change based on historical determinants and their influence on the formation, character, and dynamics of biotas along the Chilean coast, emphasizing the identification and biogeographic nature of the main spatial units. From the preceding information, I propose a hypothesis of biogeographic classification for the level of biotas, not necessarily coincident with prior studies at lower levels such as flora or fauna. This classification identifies three major spatial units: a southern area which comprises an austral biota (Magellan Province, a northern area which comprises a warm-temperate biota (Peruvian Province, and a non transitional, Intermediate Area including mixed components of biota and exhibiting a poor biogeographic definition of both its character and hierarchical rank. I also discuss the different nature of two transitional zones located at the boundaries of the Intermediate Area, a southward induced transition and a northward contact transition, likely produced by the migration of biotas and glacial-tectonic events, respectively

Rising Expectations in Brazil and Chile

Science.gov (United States)

Elacqua, Gregory; Alves, Fatima

2014-01-01

Two themes connect Brazil and Chile: one is economic success; the other is social unrest. Protests rocked cities across Brazil in June 2013, and in Chile, recent student protests turned violent. Yet living conditions in both nations are better now than they've ever been. Successful economic and social reforms over the last two decades have led to…

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.

ESO and Chile: 10 Years of Productive Scientific Collaboration

Science.gov (United States)

2006-06-01

ESO and the Government of Chile launched today the book "10 Years Exploring the Universe", written by the beneficiaries of the ESO-Chile Joint Committee. This annual fund provides grants for individual Chilean scientists, research infrastructures, scientific congresses, workshops for science teachers and astronomy outreach programmes for the public. In a ceremony held in Santiago on 19 June 2006, the European Organisation for Astronomical Research in the Southern Hemisphere (ESO) and the Chilean Ministry of Foreign Affairs marked the 10th Anniversary of the Supplementary Agreement, which granted to Chilean astronomers up to 10 percent of the total observing time on ESO telescopes. This agreement also established an annual fund for the development of astronomy, managed by the so-called "ESO-Chile Joint Committee". ESO PR Photo 21/06 ESO PR Photo 21/06 Ten Years ESO-Chile Agreement Ceremony The celebration event was hosted by ESO Director General, Dr. Catherine Cesarsky, and the Director of Special Policy for the Chilean Ministry of Foreign Affairs, Ambassador Luis Winter. "ESO's commitment is, and always will be, to promote astronomy and scientific knowledge in the country hosting our observatories", said ESO Director General, Dr. Catherine Cesarsky. "We hope Chile and Europe will continue with great achievements in this fascinating joint adventure, the exploration of the universe." On behalf of the Government of Chile, Ambassador Luis Winter outlined the historical importance of the Supplementary Agreement, ratified by the Chilean Congress in 1996. "Such is the magnitude of ESO-Chile Joint Committee that, only in 2005, this annual fund represented 8 percent of all financing sources for Chilean astronomy, including those from Government and universities", Ambassador Winter said. The ESO Representative and Head of Science in Chile, Dr. Felix Mirabel, and the appointed Chilean astronomer for the ESO-Chile Joint Committee, Dr. Leonardo Bronfman, also took part in the

Multiproxy Holocene paleoclimate records from the southern Peruvian Andes - what new can we learn from the stable carbon isotope composition of high altitude organic matter deposits?

Science.gov (United States)

Skrzypek, Grzegorz; Engel, Zbyněk

2015-04-01

Interpretation of the Central Andean paleoclimate over the last millennia still represents a research challenge demanding deeper studies [1,2]. Several high-resolution paleoclimate proxies for the last 10,000 years have been developed for the northern hemisphere. However, similar proxies are very limited for South America, particularly for high altitudes where, for example, tree-ring chronologies are not available and instrumental records are very limited. Consequently, our knowledge of high altitude climate changes in arid regions of the Peruvian Andes mainly relies on ice-core and lake deposit studies. In our study, we used a new alternative proxy for interpretation of palaeoclimate conditions based on a peat core taken from the Carhuasanta Valley at the foot of Nevado Mismi in the southern Peruvian Andes (15° 30'S, 71° 43'W, 4809m a.s.l.). The stable carbon isotope composition (δ13C) of Distichia peat reflects mainly the relative variation of the mean air temperature during subsequent growing seasons [3], and allows reconstructions of palaeotemperature changes. In contrast, peat organic carbon concentration (C % wt) records mainly wetness in the valley, directly corresponding to the changes in runoff in the upper part of the catchment. The most prominent climate changes recorded in the peat over last 4ka occurred between 3040 and 2750 cal. yrs BP. The initial warming turned to a very 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, when the temperature increased again. This event coincides with significant changes in peat and ice core records in the Central Andes that match 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

Checklist, diversity and distribution of testate amoebae in Chile.

Science.gov (United States)

Fernández, Leonardo D; Lara, Enrique; Mitchell, Edward A D

2015-10-01

Bringing together more than 170 years of data, this study represents the first attempt to construct a species checklist and analyze the diversity and distribution of testate amoebae in Chile, a country that encompasses the southwestern region of South America, countless islands and part of the Antarctic. In Chile, known diversity includes 416 testate amoeba taxa (64 genera, 352 infrageneric taxa), 24 of which are here reported for the first time. Species-accumulation plots show that in Chile, the number of testate amoeba species reported has been continually increasing since the mid-19th century without leveling off. Testate amoebae have been recorded in 37 different habitats, though they are more diverse in peatlands and rainforest soils. Only 11% of species are widespread in continental Chile, while the remaining 89% of the species exhibit medium or short latitudinal distribution ranges. Also, species composition of insular Chile and the Chilean Antarctic territory is a depauperated subset of that found in continental Chile. Nearly, the 10% of the species reported here are endemic to Chile and many of them are distributed only within the so-called Chilean biodiversity hotspot (ca. 25° S-47° S). These findings are here thoroughly discussed in a biogeographical and evolutionary context. Copyright © 2015 Elsevier GmbH. All rights reserved.

Serum levels of interleukin-6 are linked to the severity of the disease caused by Andes Virus.

Directory of Open Access Journals (Sweden)

Jenniffer Angulo

2017-07-01

Full Text Available Andes virus (ANDV is the etiological agent of hantavirus cardiopulmonary syndrome in Chile. In this study, we evaluated the profile of the pro-inflammatory cytokines IL-1β, IL-12p70, IL-21, TNF-α, IFN-γ, IL-10 and IL-6 in serum samples of ANDV-infected patients at the time of hospitalization. The mean levels of circulating cytokines were determined by a Bead-Based Multiplex assay coupled with Luminex detection technology, in order to compare 43 serum samples of healthy controls and 43 samples of ANDV-infected patients that had been categorized according to the severity of disease. When compared to the controls, no significant differences in IL-1β concentration were observed in ANDV-infected patients (p = 0.9672, whereas levels of IL-12p70 and IL-21 were significantly lower in infected cases (p = <0.0001. Significantly elevated levels of TNF-α, IFN-γ, IL-10, and IL-6 were detected in ANDV-infected individuals (p = <0.0001, 0.0036, <0.0001, <0.0001, respectively. Notably, IL-6 levels were significantly higher (40-fold in the 22 patients with severe symptoms compared to the 21 individuals with mild symptoms (p = <0.0001. Using multivariate regression models, we show that IL-6 levels has a crude OR of 14.4 (CI: 3.3-63.1. In conclusion, the serum level of IL-6 is a significant predictor of the severity of the clinical outcome of ANDV-induced disease.

From state terrorism to state errorism: post-Pinochet Chile's long search for truth and justice.

Science.gov (United States)

Wyndham, Marivic; Read, Peter

2010-02-01

Patio 29 lies in the northern sector of Santiago's General Cemetery. To the naked eye, it is a grim unweeded field of some twelve hundred rusted tin crosses. But to the families of the 1,197 detained-disappeared during Augusto Pinochet's brutal dictatorship, Patio 29 is both a site of horror and a site of hope. Its story begins in September-December 1973 when 320 early victims of the repression were brought there in makeshift wooden crates that held as many as three bodies each, and buried in unmarked graves. A few years later, two hundred of those graves were exhumed by the military, and the remains presumably cremated. For another decade, the mass grave remained silent, yielding few of its secrets to the families' demands to know: Where are they? Today, nineteen years into the so-called transition to democracy, Patio 29--the most important single finding in relation to Chile's detained-disappeared-still refuses to reveal the identities of those victims, pressing upon the government of Michelle Bachelet a new question: Who are they? First state terror, now state error have conspired to make Patio 29 one of Chile's principal horror-cum-hopescapes.

Diet, dietary selectivity and density of South American grey fox, Lycalopex griseus, in Central Chile.

Science.gov (United States)

Muñoz-Pedreros, Andrés; Yáñez, José; Norambuena, Heraldo V; Zúñiga, Alfredo

2018-01-01

The South American grey fox Lycalopex griseus is a canid widely distributed in southern South America; however, some aspects of its biology are still poorly known. We studied the diet and density of L. griseus in the Lago Peñuelas Biosphere Reserve, in Central Chile. The trophic niche breadth was B = 6.16 (B sta = 0.47) and prey diversity was H' = 2.46 (H max ' = 3.17, J' = 0.78). The highest proportions of prey consumed in the diet were Oryctolagus cuniculus (52.21%) and other mammals (32.78%). We compared these results with a latitudinal gradient of diet results for this species in Chile. L. griseus eats mostly mammals (>90% of total prey), consuming the rodent Phyllotis darwini and reptiles in the northern zone; Oryctolagus cuniculus, Octodon degus and Abrocoma bennetti in the central zone; Abrothrix spp. and lagomorphs in the southern zone; and Lepus capensis and Ovis aries in the austral zone. The estimated density of L. griseus in Lago Peñuelas NR was 1.3 foxes/km 2 . © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

On the extension of the analytic nodal diffusion solver ANDES to sodium fast reactors

International Nuclear Information System (INIS)

Ochoa, R.; Herrero, J.J.; Garcia-Herranz, N.

2011-01-01

Within the framework of the Collaborative Project for a European Sodium Fast Reactor, the reactor physics group at UPM is working on the extension of its in-house multi-scale advanced deterministic code COBAYA3 to Sodium Fast Reactors (SFR). COBAYA3 is a 3D multigroup neutron kinetics diffusion code that can be used either as a pin-by-pin code or as a stand-alone nodal code by using the analytic nodal diffusion solver ANDES. It is coupled with thermal-hydraulics codes such as COBRA-TF and FLICA, allowing transient analysis of LWR at both fine-mesh and coarse-mesh scales. In order to enable also 3D pin-by-pin and nodal coupled NK-TH simulations of SFR, different developments are in progress. This paper presents the first steps towards the application of COBAYA3 to this type of reactors. ANDES solver, already extended to triangular-Z geometry, has been applied to fast reactor steady-state calculations. The required cross section libraries were generated with ERANOS code for several configurations. Here some of the limitations encountered when attempting to apply the Analytical Coarse Mesh Finite Difference (ACMFD) method - implemented inside ANDES - to fast reactor calculations are discussed and the sensitivity of the method to the energy-group structure is studied. In order to reinforce some of the conclusions obtained two calculations are presented. The first one involves a 3D mini-core model in 33 groups, where the ANDES solver presents several issues. And secondly, a benchmark from the NEA for a small 3D FBR in hexagonal-Z geometry in 4 energy groups is used to verify the good convergence of the code in a few-energy-group structure. (author)

The forest vegetation of Ramal de Guaramacal in the Venezuelan Andes

NARCIS (Netherlands)

Cuello, A.N.L.; Cleef, A.M.

2009-01-01

Montane forest community composition of Ranial de Guaramacal, Venezuelan Andes, was studied along the altitudinal gradient on both sides of the range with different slope expositions. Thirty five 0.1 ha plots were Surveyed, with variable intervals of 30 to 150 meters between 1350 in and 2890 in and

The forest vegetation of Ramal de Guaramacal in the Venezuelan Andes

NARCIS (Netherlands)

Cuello A., N.L.; Cleef, A.M.

2009-01-01

Montane forest community composition of Ramal de Guaramacal, Venezuelan Andes, was studied along the altitudinal gradient on both sides of the range with different slope expositions. Thirty five 0.1 ha plots were surveyed, with variable intervals of 30 to 150 meters between 1350 m and 2890 m and

A new genus of Platynini (Coleoptera: Carabidae) from Argentina

OpenAIRE

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 ...

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

Directory of Open Access Journals (Sweden)

A. Casteller

2008-05-01

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

Mepraia spinolai in the Southeastern Pacific Ocean Coast (Chile - First insular record and feeding pattern on the Pan de Azúcar Island

Directory of Open Access Journals (Sweden)

Sagua Franco Hernán

2000-01-01

Full Text Available In a field collection performed at Pan de Azúcar Island in Northern Chile, 95 specimens representing all instars of Mepraia spinolai were collected. The intestinal contents of 55 specimens were examined for Trypanosoma cruzi infection and were found to be negative. This is the first record of an insular habitat for M. spinolai, where the insects had fed mainly on seabirds (78%, some on marine mammals (5%, and some on reptiles (7%.

Chile: los mapuches y el Bicentenario Chile: Mapuches e do Bicentenario Chile: Mapuche and the Bicentennial

Directory of Open Access Journals (Sweden)

José Bengoa

2011-12-01

Full Text Available El Bicentenario de la República de Chile se conmemoró en el mes de septiembre del año 2010. Además de marcar un importante hito histórico, coincidió con un cambio político en el Gobierno del país, el que pasó de la Concertación de Partidos por la Democracia a la Alianza de partidos formada por la derecha chilena. Se cumplieron por tanto 20 años desde que en el año 1990 cambiara el Gobierno militar presidido por el general Pinochet. Ese largo tiempo, dos décadas, coincide con un período de políticas que el Estado ha implementado hacia los Pueblos Indígenas. El Proyecto “Conmemoraciones y Memorias Subalternas” ha realizado durante el año 2010 un conjunto de investigaciones de terreno y documentales tendientes a comprender del modo más objetivo y científico lo ocurrido en el período y por tanto la situación actual de las sociedades mapuches en sus complejas relaciones con la chilena.O Bicentenario da República do Chile comemorou-se no mês de Setembro do ano 2010. Junto com transformar-se num marco histórico, coincidiu com uma mudança política no Governo do país, que passou da Concertação de Partidos pela Democracia (centro-esquerda à Aliança de partidos formada pela direita chilena. Cumpriram-se por tanto 20 anos desde que em 1990 mudasse o Governo militar presidido pelo general Pinochet. Esse longo tempo, duas décadas, coincide com um período de políticas que o Estado implementou para com os Povos Indígenas. O Projeto “Comemorações e Memórias Subalternas” realizou durante o ano 2010 um conjunto de pesquisas de campo e documentais tendentes a compreender do modo mais objetivo e científico o ocorrido no período e, por tanto, a situação atual das sociedades mapuches em suas complexas relações com a chilena.The conmeration of the 200 years of the Independence of Chile was in September 2010. This year was also the political change from the Concertación de Partidos por la Democracia to the right

Evaluation of Water Resources in Bolivia, South America

Science.gov (United States)

1991-01-01

liters/second demanded). Because of the effects of the drought, SEMAPA (Servicio Municipal de Agua Potables y Alcantarillado, the area water supply...departments of Potosi and Cochabamba and is in the eastern range of the Andes mountains. The western edge of the department borders Chile and is in the...Cochabamba to the east, Potosi to the south and Chile to the West. Encompassing 53,588 square kilometers, Oruro ranks fifth in size out of the seven

Phylogeny of Neotropical Cercosaura (Squamata: Gymnophthalmidae) lizards.

Science.gov (United States)

Torres-Carvajal, Omar; Lobos, Simón E; Venegas, Pablo J

2015-12-01

Among Neotropical lizards, the geographically widespread gymnophthalmid Cercosaura as currently defined includes lowland and highland taxa from Panama to Argentina, with some species occurring in the northern Andes. In this study we analyze three mitochondrial (12S, 16S, ND4) and one nuclear (c-mos) gene using Bayesian methods to clarify the phylogenetic relationships among most species of Cercosaura based on a well-supported phylogenetic hypothesis that also includes a large sample of other taxa within Cercosaurini. The phylogenetic tree obtained in this paper shows that Cercosaura as currently defined is not monophyletic. Two species from the northern Andes (C. dicra and C. vertebralis) are nested within Pholidobolus, which has been formerly recognized as a major radiation along the Andes of Ecuador and Colombia. Therefore, Cercosaura has probably not diversified in the northern Andes, although the phylogenetic position of C. hypnoides from the Andes of Colombia remains unknown. Tree topology and genetic distances support both recognition of C. ocellata bassleri as a distinct species, C. bassleri, and recognition of C. argula and C. oshaughnessyi as two different species. In the interest of promoting clarity and precision regarding the names of clades of gymnophthalmid lizards, we propose a phylogenetic definition of Cercosaura. Copyright © 2015 Elsevier Inc. All rights reserved.

Oxygenation variability in Mejillones Bay, off northern Chile, during the last two centuries

Science.gov (United States)

Díaz-Ochoa, J. A.; Pantoja, S.; de Lange, G. J.; Lange, C. B.; Sánchez, G. E.; Acuña, V. R.; Muñoz, P.; Vargas, G.

2011-01-01

The Peru Chile Current ecosystem is characterized by high biological productivity and important fisheries. Although this system is likely to be severely affected by climate change, its response to current global warming is still uncertain. In this paper, we analyze 10-166 year-old sediments in two cores collected from Mejillones Bay, an anoxic sedimentary setting favorable for the preservation of proxies. Based on a 166-year chronology, we used proxies of bottom-water oxygenation (Mo, V, S, and the (lycopane + n-C35)/n-C31 ratio) and surface water productivity (biogenic opal, counts of diatom valves, biogenic Ba, organic carbon, and chlorins) to reconstruct environmental variations in Mejillones Bay. During the last two centuries, a shift took place in the coastal marine ecosystem of Bahia Mejillones at decadal scales. This shift was characterized by intense ENSO-like activity, large-scale fluctuations in biological export productivity and bottom water oxygenation, and increased eolian activity (inferred from Ti/Al and Zr/Al). This short-term variability was accompanied by a gradual increase of sulfidic conditions that has intensified since the early 1960s.

Palm harvest impact in the western Amazon, Andes and Pacific lowlands

DEFF Research Database (Denmark)

Balslev, Henrik

2011-01-01

Palms are the most useful group of plants in tropical American forests and in this project we study the effect of extraction and trade of palms on forests in the western Amazon, Andes, and Pacific lowlands. We determine the size of the resource by making palm community studies in the different...

[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.

Landscape-based discretization for modeling of hydrological processes in the semi-arid Andes Cordillera: a case study in Morales Basin

Science.gov (United States)

Videla Giering, Y. A., III; McPhee, J. P.; Pomeroy, J. W.

2017-12-01

Improved understanding of cryosphere processes in the Subtropical Andes is essencial to secure water supply in Central Chile. An ongoing challenge is to identify the main controls on snow accumulation and ablation at multiple scales. In this study, we use the Cold Regions hydrological model (CRHM) to simulate the evolution of seasonal snow cover in the basin of the Estero Morales between the period 2000-2016. The model was forced with radiation, temperature, humidity, wind and precipitation data obtained from downscaled Era-Interim outputs. The basin was disaggregated spatially through representative hydrological processes and and geomorphological into HRU's. 22% of snow in the basin is subject to reallocation by topographic effects, while net short wave radiation would explain major changes in snowmelt. 80% of summer runoff comes from glacial melting, while temperature and soil properties are key factors controlling infiltration and contribution to the runoff at all times of the year. The model results indicate that 78.2% of precipitation corresponds to snow while 21.8% to rain. The flow rates of snowmelting are the main component in the water balance, accounting for approximately 62.8% of the total rainfall. It is important to point out that during the total period of modeling (2010-2016), it was noted that the 23.08% of the total annual flow corresponds to glacial melting, however for the period 2010 - 2015 this percentage increases to 45.3%, in spite of this were not observed variations in the volume of subsurface and groundwater flow. This suggests first: that systems such as analyzed in this article, have a great importance because they are fragile in terms of response and the ground due to its topographic features (such as slope and conductivity) is not able to store large percentages of resources until the end of the summer season; and second, to understand that mountain systems with presence of glaciers, naturally are regulated compared to sudden changes

Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes.

OpenAIRE

Manzanilla, María D.; Molina de González Méndez, Tivizay; Caltagirone, Raimondo; Vera , Mariflor; Torres, Adrián R.

2007-01-01

Editorial. ¡Ya tenemos símbolo, ícono o logotipo!. Now we have symbol, icono or logo!. Salinas, Pedro José Accidentes domésticos en ancianos. Municipio Libertador. Mérida. 1993-1996. Domestics accidents in elderly people. Libertador County of Mérida State. 1993-1996. Salinas, Pedro José Rojas Márquez, Reina Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes. Stress and symptoms in health staff of the Hospital Universitario de Los Andes. Méri...

Mycorrhizal compatibility and symbiotic seed germination of orchids from the Coastal Range and Andes in south central Chile.

Science.gov (United States)

Herrera, Hector; Valadares, Rafael; Contreras, Domingo; Bashan, Yoav; Arriagada, Cesar

2017-04-01

Little is known about Orchidaceae plants in Chile and their mycorrhizal associations, a key issue for designing protective actions for endangered species. We investigated root fungi from seven terrestrial orchid species to identify potential mycorrhizal fungi. The main characteristics of Rhizoctonia-like fungi were observed under light microscopy, and isolates were identified through PCR-ITS sequencing. Molecular identification of fungal sequences showed a high diversity of fungi colonizing roots. Fungal ability to germinate seeds of different orchids was determined in symbiotic germination tests; 24 fungal groups were isolated, belonging to the genera Tulasnella, Ceratobasidium, and Thanatephorus. Furthermore, dark septate and other endophytic fungi were identified. The high number of Rhizoctonia-like fungi obtained from adult orchids from the Coastal mountain range suggests that, after germination, these orchids may complement their nutritional demands through mycoheterotrophy. Nonetheless, beneficial associations with other endophytic fungi may also co-exist. In this study, isolated mycorrhizal fungi had the ability to induce seed germination at different efficiencies and with low specificity. Germin ation rates were low, but protocorms continued to develop for 60 days. A Tulasnella sp. isolated from Chloraea gavilu was most effective to induce seed germination of different species. The dark septate endophytic (DSE) fungi did not show any effect on seed development; however, their widespread occurrence in some orchids suggests a putative role in plant establishment.

Tectonic control of erosion in the southern Central Andes

Science.gov (United States)

Val, Pedro; Venerdini, Agostina L.; Ouimet, William; Alvarado, Patricia; Hoke, Gregory D.

2018-01-01

Landscape evolution modeling and global compilations of exhumation data indicate that a wetter climate, mainly through orographic rainfall, can govern the spatial distribution of erosion rates and crustal strain across an orogenic wedge. However, detecting this link is not straightforward since these relationships can be modulated by tectonic forcing and/or obscured by heavy-tailed frequencies of catchment discharge. This study combines new and published along-strike average rates of catchment erosion constrained by 10Be and river-gauge data in the Central Andes between 28°S and 36°S. These data reveal a nearly identical latitudinal pattern in erosion rates on both sides of the range, reaching a maximum of 0.27 mm/a near 34°S. Collectively, data on topographic and fluvial relief, variability of rainfall and discharge, and crustal seismicity suggest that the along-strike pattern of erosion rates in the southern Central Andes is largely independent of climate, but closely relates to the N-S distribution of shallow crustal seismicity and diachronous surface uplift. The consistently high erosion rates on either side of the orogen near 34°S imply that climate plays a secondary role in the mass flux through an orogenic wedge where the perturbation to base level is similar on both sides.

Studies to Control Endemic Typhoid Fever in Chile

Science.gov (United States)

1983-01-30

Bol. Inst. Bacteriol. Chile 1976; 18:33-37. 30. Escaff, M, Urbina, A, Mary, J. Contaminacion de repollos regados con aguas servidas. Agricultura...Tecnica 1979; 39:59-62. - 31. Lobos, H, Greive, R, Quijada, M, Brandt, H. Pesquisa del genero Vibrio en aguas servidas. Bol. Inst. Bact. Chile 1974; 16:40...REPORT #2 0") STUDIES TO CONTROL ENDEMIC TYPHOID N FEVER IN CHILE 0) ANNUAL REPORT U’ Contract Period 1/1/82-12/31/82 • I REPORT PREPARED BY: L

Far-IR measurements at Cerro Toco, Chile: FIRST, REFIR, and AERI

Science.gov (United States)

Cageao, Richard P.; Alford, J. Ashley; Johnson, David G.; Kratz, David P.; Mlynczak, Martin G.

2010-09-01

In mid-2009, the Radiative Heating in the Underexplored Bands Campaign II (RHUBC-II) was conducted from Cerro Toco, Chile, a high, dry, remote mountain plateau, 23°S , 67.8°W at 5.4km, in the Atacama Desert of Northern Chile. From this site, dominant IR water vapor absorption bands and continuum, saturated when viewed from the surface at lower altitudes, or in less dry locales, were investigated in detail, elucidating infrared (IR) absorption and emission in the atmosphere. Three Fourier Transform InfraRed (FTIR) instruments were at the site, the Far-Infrared Spectroscopy of the Troposphere (FIRST), the Radiation Explorer in the Far Infrared (REFIR), and the Atmospheric Emitted Radiance Interferometer (AERI). In a side-by-side comparison, these measured atmospheric downwelling radiation, with overlapping spectral coverage from 5 to 100μm (2000 to 100cm-1), and instrument spectral resolutions from 0.5 to 0.643cm-1, unapodized. In addition to the FTIR and other ground-based IR and microwave instrumentation, pressure/temperature/relative humidity measuring sondes, for atmospheric profiles to 18km, were launched from the site several times a day. The derived water vapor profiles, determined at times matching the FTIR measurement times, were used to model atmospheric radiative transfer. Comparison of instrument data, all at the same spectral resolution, and model calculations, are presented along with a technique for determining adjustments to line-by-line calculation continuum models. This was a major objective of the campaign.

Resignificación de la muerte en los Andes: La festividad de Wiñay Pacha o todas las almas en Santiago de Chile

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Francisca Fernández Droguett

2014-12-01

Full Text Available Desde el 2009 diversas organizaciones y agrupaciones de danza y música andina, han comenzado a conmemorar el día de difuntos en la ciudad de Santiago, denominándola Wiñay Pacha o Todas Almas. El siguiente artículo tiene por objetivo caracterizar esta práctica festiva desde los elementos culturales que configuran la visión de la muerte de los pueblos indígenas de Los Andes, a través de la vivencia del duelo y la forma de conmemorar a los difuntos, para luego reflexionar el modo en que se ha ido resignificando en el contexto urbano, mediante la revisión de su origen como festividad y su expresión como reivindicación de otros modos de vivenciar la muerte. La investigación se aborda desde una aproximación etnográfica, utilizando para la recopilación de datos la revisión bibliográfica, observación participante y entrevistas en profundidad.

Expedition Atacama - project AMOS in Chile

Science.gov (United States)

Tóth, J.; Kaniansky, S.

2016-01-01

The Slovak Video Meteor Network operates since 2009 (Tóth et al., 2011). It currently consists of four semi-automated all-sky video cameras, developed at the Astronomical Observatory in Modra, Comenius University in Bratislava, Slovakia. Two new generations of AMOS (All-sky Meteor Orbit System) cameras operate fully automatically at the Canary Islands, Tenerife and La Palma, since March 2015 (Tóth et al., 2015). As a logical step, we plan to cover the southern hemisphere from Chile. We present observational experiences in meteor astronomy from the Atacama Desert and other astronomical sites in Chile. This summary of the observations lists meteor spectra records (26) between Nov.5-13, 2015 mostly Taurid meteors, single and double station meteors as well as the first light from the permanent AMOS stations in Chile.

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

Strengthen the use of scientific evidence to inform climate policy, negotiations ... Evaluating the impact of digital tools to teach math and science in Chile ... Business Cooperation and Regional Productive Development in Chile, El Salvador, ...

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...

The 2011-2012 eruption of Cordón Caulle volcano (Southern Andes): Evolution, crisis management and current hazards

Science.gov (United States)

Silva Parejas, C.; Lara, L. E.; Bertin, D.; Amigo, A.; Orozco, G.

2012-04-01

A new kind of integrated approach was for first time achieved during the eruptive crisis of Cordón Caulle volcano (Southern Andes, 40.59°S, 72.12°W) in Chile. The monitoring network of SERNAGEOMIN around the volcano detected the increasing precursory seismicity, alerting the imminence of an eruption about 5 hours before its onset, on June 4, 2011. In addition, SERNAGEOMIN generated daily forecasts of tephra dispersal and fall (ASHFALL advection-diffusion model), and prepared simulations of areas affected by the possible occurrence of lahars and pyroclastic flows. Models were improved with observed effects on the field and satellite imagery, resulting in a good correlation. The information was timely supplied to the authorities as well as recommendations in order to better precise the vulnerable areas. Eruption has initially occurred from a couple of overlapped cones located along the eastern fault scarp of the Pleistocene-Holocene extensional graben of Cordón Caulle. Eruptive products have virtually the same bulk composition as those of the historical 1921 and 1960 eruptions, corresponding to phenocryst-poor rhyodacites (67-70 % SiO2). During the first eruptive stage, a ca. 15-km strong Plinian column lasting 27 hours emitted 0.2-0.4 km3 of magma (DRE). Thick tephra deposits have been accumulated in Chile and Argentina, whereas fine particles and aerosols dispersion disrupted air navigation across the Southern Hemisphere. The second ongoing eruptive stage, which started in mid-June, has been characterized by lava emission already covering a total area comparable to the 1960 lava flows with a total estimated volume Argentina until the end of the year. Main current hazards at Cordón Caulle volcano are fine tephra fallout, secondary lahars, minor explosions and lava flow front collapse. Even if this case can be considered successful from the point of view of eruption forecast and hazard assessment, a new protocol of volcanic alerts has been recently signed

Andean tectonics: Implications for Satellite Geodesy

Science.gov (United States)

Allenby, R. J.

1984-01-01

Current knowledge and theories of large scale Andean tectonics as they relate to site planning for the NASA Crustal Dynamics Program's proposed high precision geodetic measurements of relative motions between the Nazca and South American plates are summarized. The Nazca Plate and its eastern margin, the Peru-Chile Trench, is considered a prototype plate marked by rapid motion, strong seismicity and well defined boundaries. Tectonic activity across the Andes results from the Nazca Plate subducting under the South American plate in a series of discrete platelets with different widths and dip angles. This in turn, is reflected in the tectonic complexity of the Andes which are a multitutde of orogenic belts superimposed on each other since the Precambrian. Sites for Crustal Dynamics Program measurements are being located to investigate both interplate and extraplate motions. Observing operations have already been initiated at Arequipa, Peru and Easter Island, Santiago and Cerro Tololo, Chile. Sites under consideration include Iquique, Chile; Oruro and Santa Cruz, Bolivia; Cuzco, Lima, Huancayo and Bayovar, Peru; and Quito and the Galapagos Islands, Ecuador. Based on scientific considerations, Santa Cruz, Huancayo (or Lima), Quito and the Galapagos Islands should be replaced by Isla San Felix, Chile; Brazilia or Petrolina, Brazil; and Guayaquil, Ecuador. If resources permit, additional important sites would be Buenaventura and Villavicencio or Puerto La Concordia, Colombia; and Mendoza and Cordoba, Argentina.

Anthopleura radians, a new species of sea anemone (Cnidaria: Actiniaria: Actiniidae from northern Chile, with comments on other species of the genus from the South Pacific Ocean

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Carlos Spano

2017-05-01

Full Text Available A new species of sea anemone, Anthopleura radians n. sp., is described from the intertidal zone of northern Chile and the taxonomic status of the other Anthopleura species from the South Pacific are discussed. A. radians n. sp. is characterized by a yellow-whitish and brown checkerboard-like pattern on the oral disc, adhesive verrucae along the entire column and a series of marginal projections, each bearing a brightly-colored acrorhagus on the oral surface. This is the seventh species of Anthopleura described from the South Pacific Ocean; each one distinguished by a particular combination of differences related to their coloration pattern, presence of zooxanthellae, cnidae, and mode of reproduction. Some of these species have not been reported since their original description and thus require to be taxonomically validated. A. hermaphroditica and A. aureoradiata are synonyms considering the lack of differences seen between live specimens, museum collections and published records. A. radians could also be a junior synonym of A. minima, however, no type material was found for testing this hypothesis. Furthermore, it is crucial to designate neotypes for A. inconspicua, A. rosea and A. minima since there are no name-bearing types reported for these species.

Intelectuais e política no Chile: Apontamentos sobre a revista Aurora de Chile (1938-1940

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Ana Amélia M.C. Melo

Full Text Available Resumo O objetivo deste artigo é o de examinar a revista Aurora de Chile que circula em Santiago entre 1938-1940. Criada por Pablo Neruda esta publicação apresentou-se como um importante órgão de comunicação da Alianza de Intelectuales de Chile para la Defensa de la Cultura (AICH, entidade fundada em articulação com outras organizações internacionais de intelectuais e com orientação da Comintern. A revista situou-se nos debates políticos e culturais desses anos no Chile e atuou vigorosamente na defesa dos princípios da democracia, das liberdades públicas e contra o fascismo. Neste estudo busco demonstrar o papel desta revista como uma das vozes da perspectiva frentista que passou a orientar o Partido Comunista Chileno no período.

[Health inequality gap in inmigrant versus local children in Chile].

Science.gov (United States)

Cabieses, Baltica; Chepo, Macarena; Oyarte, Marcela; Markkula, Niina; Bustos, Patricia; Pedrero, Víctor; Delgado, Iris

2017-12-01

Children and young international migrants face different health challenges compa red with the local population, particularly if they live in insecure environments or adverse social conditions. This study seeks to identify gaps in health outcomes of children between immigrant and local population in Chile. This study analyses data from three sources: (i) Born in Chile: Electronic records of antenatal visits from all municipal antenatal clinics of Recoleta in 2012; (ii) Growing up in Chile: Population survey "National Socioeconomic Characterization" (CASEN) from 2013 and (iii) Getting sick in Chile: Data of all hospital discharges in 2012, provided by the department of statistics and health information (DEIS) of the Ministry of Health. (I) Born in Chile: Im migrants more frequently have psychosocial risk (62.3% vs 50.1% in Chileans) and enter later into the program (63.1% vs 33.4% enter later than 14 weeks of pregnancy). All birth outcomes were better among immigrants (e.g. caesarean sections rates: 24.2% immigrants vs % Chileans). (ii) Growing up in Chile: A higher proportion of migrant children is outside the school system and lives in multidi mensional poverty (40% immigrants vs 23.2% Chileans). (iii) Getting sick in Chile: Injuries and other external causes were more frequent cause of hospitalisation among migrants (23.6%) than the local population (16.7%) aged between 7 and 14 years. Addressing the needs of the children in Chile, regardless of their immigration status, is an ethical, legal and moral imperative.

Primer "Entrenamiento en Metodologías de Investigación Clínica en Chile" (EMIC-Chile: Fundamentos psicoeducativos

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B. Cabieses

Full Text Available EMIC-Chile ("Entrenamiento en Metodologías para la Investigación Clínica en Chile" es un proyecto académico desarrollado durante el año 2008 en Chile para entrenar a profesionales de la salud y disciplinas afines en metodología de investigación clínica, con el objetivo de aumentar la calidad de los proyectos de investigación con fines concursables en nuestro país. El propósito de este artículo es dar a conocer el programa y sus fundamentos teóricos de enseñanza-aprendizaje, que estuvieron en la base de la estructura, metodología, evaluación y sistematización del conocimiento entregado. Para ello, primero se describe el programa, la metodología, la evaluación y el seguimiento. Posteriormente se detallan los aspectos psicoeducativos considerados, con especial énfasis en el aprendizaje social y la educación de adultos. Finalmente, se discute en torno a las posibles consideraciones de este programa para futuras intervenciones educativas en investigación en salud en Chile. Se espera que esta experiencia y sus fundamentos educativos sirvan de motor para futuras iniciativas en el área, a favor de la investigación en salud en Chile.

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

Science.gov (United States)

2009-09-01

fall) 2008. As shown later, the event had typical features and produced 30–50 mm of rainfall in central Chile. Our analysis is based on in situ and...collective comments and suggestions have greatly improved the manuscript. We also thank Direccion de Aguas of Chile, and Mr. Dan Dawson of the

Eso's Situation in Chile

Science.gov (United States)

1995-02-01

ESO, the European Southern Observatory, in reply to questions raised by the international media, as well as an ongoing debate about the so-called "Paranal case" in Chilean newspapers, would like to make a number of related observations concerning its status and continued operation in that country [1]. THE ESO OBSERVATORY SITES IN CHILE The European Southern Observatory, an international organisation established and supported by eight European countries, has been operating more than 30 years in the Republic of Chile. Here ESO maintains one of the world's prime astronomical observatories on the La Silla mountain in the southern part of the Atacama desert. This location is in the Fourth Chilean Region, some 600 km north of Santiago de Chile. In order to protect the La Silla site against dust and light pollution from possible future mining industries, roads and settlements, ESO early acquired the territory around this site. It totals about 825 sq. km and has effectively contributed to the preservation of its continued, excellent "astronomical" quality. Each year, more than 500 astronomers from European countries, Chile and elsewhere profit from this when they come to La Silla to observe with one or more of the 15 telescopes now located there. In 1987, the ESO Council [2] decided to embark upon one of the most prestigious and technologically advanced projects ever conceived in astronomy, the Very Large Telescope (VLT). It will consist of four interconnected 8.2-metre telescopes and will become the largest optical telescope in the world when it is ready. It is safe to predict that many exciting discoveries will be made with this instrument, and it will undoubtedly play a very important role in our exploration of the distant universe and its many mysteries during the coming decades. THE VLT AND PARANAL In order to find the best site for the VLT, ESO performed a thorough investigation of many possible mountain tops, both near La Silla and in Northern Chile. They showed

A solar radiation database for Chile.

Science.gov (United States)

Molina, Alejandra; Falvey, Mark; Rondanelli, Roberto

2017-11-01

Chile hosts some of the sunniest places on earth, which has led to a growing solar energy industry in recent years. However, the lack of high resolution measurements of solar irradiance becomes a critical obstacle for both financing and design of solar installations. Besides the Atacama Desert, Chile displays a large array of "solar climates" due to large latitude and altitude variations, and so provides a useful testbed for the development of solar irradiance maps. Here a new public database for surface solar irradiance over Chile is presented. This database includes hourly irradiance from 2004 to 2016 at 90 m horizontal resolution over continental Chile. Our results are based on global reanalysis data to force a radiative transfer model for clear sky solar irradiance and an empirical model based on geostationary satellite data for cloudy conditions. The results have been validated using 140 surface solar irradiance stations throughout the country. Model mean percentage error in hourly time series of global horizontal irradiance is only 0.73%, considering both clear and cloudy days. The simplicity and accuracy of the model over a wide range of solar conditions provides confidence that the model can be easily generalized to other regions of the world.

Future Temperatures and Precipitations in the Arid Northern-Central Chile: A Multi-Model Downscaling Approach

Science.gov (United States)

Souvignet, M.; Heinrich, J.

2010-03-01

Downscaling of global climate outputs is necessary to transfer projections of potential climate change scenarios to local levels. This is of special interest to dry mountainous areas, which are particularly vulnerable to climate change due to risks of reduced freshwater availability. These areas play a key role for hydrology since they usually receive the highest local precipitation rates stored in form of snow and glaciers. In the central-northern Chile (Norte Chico, 26-33ºS), where agriculture still serves as a backbone of the economy as well as ensures the well being of people, the knowledge of water resources availability is essential. The region is characterised by a semiarid climate with a mean annual precipitation inferior to 100mm. Moreover, the local climate is also highly influenced by the ENSO phenomenon, which accounts for the strong inter-annual variability in precipitation patterns. Although historical and spatially extensive precipitation data in the headwaters of the basins in this region are not readily available, records at coastal stations show worrisome trends. For instance, the average precipitation in La Serena, the most important city located in the Coquimbo Region, has decreased dramatically in the past 100 years. The 30-year monthly average has decreased from 170 mm in the early 20th century to values less than 80 mm nowadays. Climate Change is expected to strengthen this pattern in the region, and therefore strongly influence local hydrological patterns. The objectives of this study are i) to develop climate change scenarios (2046-2099) for the Norte Chico using multi-model predictions in terms of temperatures and precipitations, and ii) to compare the efficiency of two downscaling techniques in arid mountainous regions. In addition, this study aims at iii) providing decision makers with sound analysis of potential impact of Climate Change on streamflow in the region. For the present study, future local climate scenarios were developed

Mountain building in the central Andes

Science.gov (United States)

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

Evaluation of the hydrogeological interconnection between the Salar de Maricunga and the Piedra Pomez basins, Atacama Region, Chile; An isotope and geochemical approach

International Nuclear Information System (INIS)

Iriarte, S.; Santibanez, I; Aravena, R

2001-01-01

Groundwater is the main water source for the mining industry in the Altiplano of northern Chile. Groundwater also plays a significant role as a water source for lagoons, wetlands and salares, which are important ecosystems for animal life and vegetation communities that exist in this arid region. The rational use and protection of the groundwater resource requires a good understanding of the aquifer systems. One of the key components in the assessment of water resources in Northern Chile, is the hydrogeological interconnection between basins. During the last three years, as part of a major hydrogeological project, Sernageomin has been working in the Altiplano of the Atacama region (Iriarte et al., 1998; Iriarte, 1999; Venegas et al., 2000; Santibanez, in prep.). This study included the evaluation of the geometry and groundwater potential of the aquifers and the chemical characterization of the surface and groundwater. Part of this study has focused on the Salar de Maricunga and the Campo de Piedra Pomez basins, due to an increasing demand for groundwater resources in this area by the mining industry. This paper discusses the use of isotope and geochemical tools that were used to evaluate the hydrogeological interconnection between the Salar de Maricunga and the Piedra Pomez basins. The geological and hydrogeological framework of this work is discussed in detail by Iriarte (1999) (au)

Hybrid Literacies: The Case of a Quechua Community in the Andes

Science.gov (United States)

de la Piedra, Maria Teresa

2009-01-01

Drawing on data from an ethnographic study in a Quechua rural community in the Peruvian Andes, this article examines hybrid literacy practices among bilingual rural speakers in the context of the household and the community. I examine the coexistence of two types of textual practices that operate side by side, at times integrated in the same…

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.

First record of Phoebis argante chincha Lamas (Lepidoptera, Pieridae in Chile

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Héctor A. Vargas

2011-09-01

Full Text Available First record of Phoebis argante chincha Lamas (Lepidoptera, Pieridae in Chile. The presence of Phoebis argante chincha Lamas, 1976 (Lepidoptera, Pieridae is reported for the first time in Chile, from the Azapa valley, Arica.Primeiro registro de Phoebis argante chincha Lamas (Lepidoptera, Pieridae no Chile. A presença de Phoebis argante chincha Lamas, 1976 (Lepidoptera; Pieridae é mencionada pela primeira vez para o Chile, no vale de Azapa, Arica.

[Consumption of antidepressants in Chile from 1992 to 2004].

Science.gov (United States)

Jirón, Marcela; Machado, Márcio; Ruiz, Inés

2008-09-01

Data from the Ministry of Health show that in Chile in 2004, 17% of the population had some form of depression, and mood disorders are the tenth cause of disability-adjusted life years (DALY) loss. To determine consumption of antidepressants (ADs) in Chile from 1992 to 2004. National sales data were obtained from the company IMS Health Chile and converted into defined daily doses (DDDs) per 1,000 inhabitants per day. Available ADs were classified in four pharmacological groups (i.e., serotonin-norepinephrine reuptake inhibitors, SNRLs; selective-serotonin reuptake inhibitors, SSRLs; tricyclic antidepressants, TCAs; and others). Total economic burden of ADs utilization and cost per DDDs were also calculated. Trends over time were analyzed using Pearson-R2. Total ADs consumption in Chile measured by DDDs per 1,000 inhabitants per day (DHD) increased linearly (y =0.901x + 1.9129; R2 =0.9296; p economic burden of ADs in Chile (total cost of DDDs consumed) increased from US$65.4 million in 2001 to US$74.6 million in 2004 (14% increase). Average cost per DDD of all AD increased linearly, however not significantly from US$ 0.94 in 2001 to US$ 1.04 in 2004 (y =0.0362x + 0.8784; R2 =0.7382; p =0,262). DDDs per 1,000 inhabitants per day increased linearly over 470% from 1992-2004. SSRLs were the most commonly consumed drugs in Chile. Future research should evaluate the cost-effectiveness of antidepressants in Chile, comparing the results with drug utilization, and determining if unnecessary expenditures have been paid out.

ISOSTATICALLY DISTURBED TERRAIN OF NORTHWESTERN ANDES MOUNTAINS FROM SPECTRALLY CORRELATED FREE-AIR AND GRAVITY TERRAIN DATA

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Hernández P Orlando

2006-12-01

Full Text Available Recently revised models on global tectonics describe the convergence of the North Andes, Nazca, Caribbean and South American Plates and their seismicity, volcanism, active faulting and extreme
topography. The current plate boundaries of the area are mainly interpreted from volcanic and seismic datasets with variable confidence levels. New insights on the isostatic state and plate boundaries of
the northwestern Andes Mountains can be obtained from the spectral analysis of recently available gravity and topography data.
Isostatically disturbed terrain produces free-air anomalies that are highly correlated with the gravity effects of the terrain. The terrain gravity effects (TGE and free air gravity anomalies (FAGA of the
Andes mountains spectral correlation data confirms that these mountains are isostatically disturbed. Strong negative terrain-correlated FAGA along western South America and the Greater and Lesser Antilles are consistent with anomalously deepened mantle displaced by subducting oceanic plates.

Inversion of the compensated terrain gravity effects (CTGE reveals plate subduction systems with alternating shallower and steeper subduction angles. The gravity modeling highlights crustal
deformation from plate collision and subduction and other constraints on the tectonism of the plate boundary zones for the region.

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.

Oxygenation variability in Mejillones Bay, off northern Chile, during the last two centuries

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J. A. Díaz-Ochoa

2011-01-01

Full Text Available The Peru Chile Current ecosystem is characterized by high biological productivity and important fisheries. Although this system is likely to be severely affected by climate change, its response to current global warming is still uncertain. In this paper, we analyze 10–166 year-old sediments in two cores collected from Mejillones Bay, an anoxic sedimentary setting favorable for the preservation of proxies. Based on a 166-year chronology, we used proxies of bottom-water oxygenation (Mo, V, S, and the (lycopane + n−C₃₅/n−C₃₁ ratio and surface water productivity (biogenic opal, counts of diatom valves, biogenic Ba, organic carbon, and chlorins to reconstruct environmental variations in Mejillones Bay. During the last two centuries, a shift took place in the coastal marine ecosystem of Bahia Mejillones at decadal scales. This shift was characterized by intense ENSO-like activity, large-scale fluctuations in biological export productivity and bottom water oxygenation, and increased eolian activity (inferred from Ti/Al and Zr/Al. This short-term variability was accompanied by a gradual increase of sulfidic conditions that has intensified since the early 1960s.

Ausentismo laboral de causa médica en el Instituto Autónomo Hospital Universitario de Los Andes.

OpenAIRE

Parada de Denis, María Eugenia; Rivas Padilla, Fernando; Moreno Barrios, Reyla; Rincón, Eglis; Mejía, Zurayma; Mora, Dania Margarita

2006-01-01

Editorial. ¡Ya tenemos símbolo, ícono o logotipo!. Now we have symbol, icono or logo!. Salinas, Pedro José Accidentes domésticos en ancianos. Municipio Libertador. Mérida. 1993-1996. Domestics accidents in elderly people. Libertador County of Mérida State. 1993-1996. Salinas, Pedro José Rojas Márquez, Reina Estrés y síntomas en personal de salud del Hospital Universitario de Los Andes. Stress and symptoms in health staff of the Hospital Universitario de Los Andes. Méri...

Snow cover dynamics in Andean watersheds of Chile (32.0–39.5° S during the years 2000–2016

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A. Stehr

2017-10-01

Full Text Available Andean watersheds present important snowfall accumulation mainly during the winter, which melts during the spring and part of the summer. The effect of snowmelt on the water balance can be critical to sustain agriculture activities, hydropower generation, urban water supplies and wildlife. In Chile, 25 % of the territory between the region of Valparaiso and Araucanía comprises areas where snow precipitation occurs. As in many other difficult-to-access regions of the world, there is a lack of hydrological data of the Chilean Andes related to discharge, snow courses, and snow depths, which complicates the analysis of important hydrological processes (e.g. water availability. Remote sensing provides a promising opportunity to enhance the assessment and monitoring of the spatial and temporal variability of snow characteristics, such as the snow cover area (SCA and snow cover dynamic (SCD. With regards to the foregoing questions, the objective of the study is to evaluate the spatiotemporal dynamics of the SCA at five watersheds (Aconcagua, Rapel, Maule, Biobío and Toltén located in the Chilean Andes, between latitude 32.0 and 39.5° S, and to analyse its relationship with the precipitation regime/pattern and El Niño–Southern Oscillation (ENSO events. Those watersheds were chosen because of their importance in terms of their number of inhabitants, and economic activities depending on water resources. The SCA area was obtained from MOD10A2 for the period 2000–2016, and the SCD was analysed through a number of statistical tests to explore observed trends. In order to verify the SCA for trend analysis, a validation of the MOD10A2 product was done, consisting of the comparison of snow presence predicted by MODIS with ground observations. Results indicate that there is an overall agreement of 81 to 98 % between SCA determined from ground observations and MOD10A2, showing that the MODIS snow product can be taken as a feasible remote sensing

The analytic nodal diffusion solver ANDES in multigroups for 3D rectangular geometry: Development and performance analysis

International Nuclear Information System (INIS)

Lozano, Juan-Andres; Garcia-Herranz, Nuria; Ahnert, Carol; Aragones, Jose-Maria

2008-01-01

In this work we address the development and implementation of the analytic coarse-mesh finite-difference (ACMFD) method in a nodal neutron diffusion solver called ANDES. The first version of the solver is implemented in any number of neutron energy groups, and in 3D Cartesian geometries; thus it mainly addresses PWR and BWR core simulations. The details about the generalization to multigroups and 3D, as well as the implementation of the method are given. The transverse integration procedure is the scheme chosen to extend the ACMFD formulation to multidimensional problems. The role of the transverse leakage treatment in the accuracy of the nodal solutions is analyzed in detail: the involved assumptions, the limitations of the method in terms of nodal width, the alternative approaches to implement the transverse leakage terms in nodal methods - implicit or explicit -, and the error assessment due to transverse integration. A new approach for solving the control rod 'cusping' problem, based on the direct application of the ACMFD method, is also developed and implemented in ANDES. The solver architecture turns ANDES into an user-friendly, modular and easily linkable tool, as required to be integrated into common software platforms for multi-scale and multi-physics simulations. ANDES can be used either as a stand-alone nodal code or as a solver to accelerate the convergence of whole core pin-by-pin code systems. The verification and performance of the solver are demonstrated using both proof-of-principle test cases and well-referenced international benchmarks

The 2012-2014 eruptive cycle of Copahue Volcano, Southern Andes. Magmatic-Hydrothermal system interaction and manifestations.

Science.gov (United States)

Morales, Sergio; Alarcón, Alex; Basualto, Daniel; Bengoa, Cintia; Bertín, Daniel; Cardona, Carlos; Córdova, Maria; Franco, Luis; Gil, Fernando; Hernandez, Erasmo; Lara, Luis; Lazo, Jonathan; Mardones, Cristian; Medina, Roxana; Peña, Paola; Quijada, Jonathan; San Martín, Juan; Valderrama, Oscar

2015-04-01

Copahue Volcano (COPV), in Southern Andes of Chile, is an andesitic-basaltic stratovolcano, which is located on the western margin of Caviahue Caldera. The COPV have a NE-trending fissure with 9 aligned vents, being El Agrio the main currently active vent, with ca. 400 m in diameter. The COPV is placed into an extensive hydrothermal system which has modulated its recent 2012-2014 eruptive activity, with small phreatic to phreatomagmatic eruptions and isolated weak strombolian episodes and formation of crater lakes inside the main crater. Since 2012, the Southern Andes Volcano Observatory (OVDAS) carried out the real-time monitoring with seismic broadband stations, GPS, infrasound sensors and webcams. In this work, we report pre, sin, and post-eruptive seismic activity of the last two main eruptions (Dec, 2012 and Oct, 2014) both with different seismic precursors and superficial activity, showing the second one a particularly appearance of seismic quiescence episodes preceding explosive activity, as an indicator of interaction between magmatic-hydrothermal systems. The first episode, in late 2012, was characterized by a low frequency (0.3-0.4 Hz and 1.0-1.5 Hz) continuous tremor which increased gradually from background noise level amplitude to values of reduced displacement (DR), close to 50 cm2 at the peak of the eruption, reaching an eruptive column of ~1.5 km height. After few months of recording low energy seismicity, a sequence of low frequency, repetitive and low energy seismic events arose, with a frequency of occurrence up to 300 events/hour. Also, the VLP earthquakes were added to the record probably associated with magma intrusion into a deep magmatic chamber during all stages of eruptive process, joined to the record of VT seismicity during the same period, which is located throughout the Caviahue Caldera area. Both kind of seismic patterns were again recorded in October 2014, being the precursor of the new eruptive cycle at this time as well as the

Observations of rapid-fire event tremor at Lascar volcano, Chile

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H. Rademacher

1996-06-01

Full Text Available During the Proyecto de Investigaciòn Sismològica de la Cordillera Occidental (PISCO '94 in the Atacama desert of Northern Chile, a continuously recording broadband seismic station was installed to the NW of the currently active volcano, Lascar. For the month of April, 1994, an additional network of three, short period, three-component stations was deployed around the volcano to help discriminate its seismic signals from other local seismicity. During the deployment, the volcanic activity at Lascar appeared to be limited mainly to the emission of steam and SO2. Tremor from Lascar is a random, «rapid-fire» series of events with a wide range of amplitudes and a quasi-fractal structure. The tremor is generated by an ensemble of independent elementary sources clustered in the volcanic edifice. In the short-term, the excitation of the sources fluctuates strongly, while the long-term power spectrum is very stationary.

Chile ushers in new hydro era

International Nuclear Information System (INIS)

Moxon, S.

1997-01-01

The planned construction of two hydroelectric power plants at Peuchen and Mampil, will help to meet Chile's growing electricity demand. Securing finance for the project has been straight forward thanks to the optimal hydrological conditions, rivers with a very strong flow providing a large head of water over short distance. Hydropower plays a central role in Chile's generating capacity providing 70% of total energy consumption. Thus, the future of these projects will be highly successful, it is argued. (UK)

Studies to Control Endemic Typhoid Fever in Chile

Science.gov (United States)

1985-09-01

Society for Microbiology, Chapter 16. 10. Medina E, Yrarrazaval M. (1983) Fiebre tifoidea en Chile: Consideraciones epideniologicas. Revista Medica de...epidesiologia de la fiebre tifoidea . Boletin de !a Escuela de Medicina, Pontificia universidad catolica de Chile. 30:113-119. 14. Reyes H, Olea M, Hernandez

Spent Fuel in Chile

International Nuclear Information System (INIS)

López Lizana, F.

2015-01-01

The government has made a complete and serious study of many different aspects and possible road maps for nuclear electric power with strong emphasis on safety and energy independence. In the study, the chapter of SFM has not been a relevant issue at this early stage due to the fact that it has been left for later implementation stage. This paper deals with the options Chile might consider in managing its Spent Fuel taking into account foreign experience and factors related to safety, economics, public acceptance and possible novel approaches in spent fuel treatment. The country’s distinctiveness and past experience in this area taking into account that Chile has two research reactors which will have an influence in the design of the Spent Fuel option. (author)

A 17-year Record of Meteorological Observations Across the Gran Campo Nevado Ice Cap in Southern Patagonia, Chile, Related to Synoptic Weather Types and Climate Modes

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Stephanie S. Weidemann

2018-05-01

Full Text Available The network of long-term meteorological observations in Southernmost Patagonia is still sparse but crucial to improve our understanding of climatic variability, in particular in the more elevated and partially glaciated Southernmost Andes. Here we present a unique 17-year meteorological record (2000–2016 of four automatic weather stations (AWS across the Gran Campo Nevado Ice Cap (53°S in the Southernmost Andes (Chile and the conventional weather station Jorge Schythe of the Instituto de la Patagonia in Punta Arenas for comparison. We revisit the relationship between in situ observations and large-scale climate models as well as mesoscale weather patterns. For this purpose, a 37-year record of ERA Interim Reanalysis data has been used to compute a weather type classification based on a hierarchical correlation-based leader algorithm. The orographic perturbation on the predominantly westerly airflow determines the hydroclimatic response across the mountain range, leading to significant west-east gradients of precipitation, air temperature and humidity. Annual precipitation sums heavily drop within only tens of kilometers from ~7,500 mm a−1 to less than 800 mm a−1. The occurrence of high precipitation events of up to 620 mm in 5 days and wet spells of up to 61 consecutive days underscore the year-around wet conditions in the Southernmost Andes. Given the strong link between large-scale circulation and orographically controlled precipitation, the synoptic-scale weather conditions largely determine the precipitation and temperature variability on all time scales. Major synoptic weather types with distinct low-pressure cells in the Weddell Sea or Bellingshausen Sea, causing a prevailing southwesterly, northwesterly or westerly airflow, determine the weather conditions in Southernmost Patagonia during 68% of the year. At Gran Campo Nevado, more than 80% of extreme precipitation events occur during the persistence of these weather types. The

75 FR 3756 - Preserved Mushrooms from Chile, China, India, and Indonesia

Science.gov (United States)

2010-01-22

...)] Preserved Mushrooms from Chile, China, India, and Indonesia AGENCY: United States International Trade... preserved mushrooms from Chile, China, India, and Indonesia. SUMMARY: The Commission hereby gives notice of... mushrooms from Chile, China, India, and Indonesia would be likely to lead to continuation or recurrence of...

Genetic composition of Mytilus species in mussel populations from southern Chile Composición genética de especies de Mytilus en poblaciones de mejillón del sur de Chile

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María Angélica Larraín

2012-11-01

Full Text Available Mussels are one of the most cultivated and commercialized bivalves worldwide and in southern Chile its culture represent an important economic activity. The species identification within the Mytilus genera, by morphological features, is unreliable, so we used a polymorphism RFLP in the gene encoding the polyphenolic adhesive protein as a species-specific genetic marker to describe Mytilus species diversity in southern Chile, and evaluate possible applications in traceability, food quality and safety. Using Me 15-16 marker most mussels were M. chilensis, finding no other pure individuals; however, putative hybrids of M. chilensis x M. trossulus and M. chilensis x M. galloprovincialis were detected. There was no evidence of M. edulis. The presence of the M. trossulus allele, faraway from its distribution area, demands further analysis with different genetic markers to allow a better understanding of its origin. In addition, the correspondence between markers that distinguishes northern from southern hemisphere M. galloprovincialis, with those who discriminates between M. chilensis and M. galloprovincialis would contribute to the taxonomic status of Chilean blue mussels. In Chile, the genetic composition of Mytilus indicates that geographical origin of mussels and its traceability cannot be established merely from the identification of the species. The use of other markers would be required.Los mejillones son una de las especies de bivalvos más cultivadas y comercializadas, en el sur de Chile donde su cultivo representa una actividad económica importante. La identificación de la especie dentro del género Mytilus, basada en las características morfológicas no es confiable por lo que se utilizó un polimorfismo RFLP en el gen que codifica la proteína adhesiva polifenólica como marcador genético específico de la especie para describir la diversidad de especies Mytilus en el sur de Chile, y evaluar posibles aplicaciones en trazabilidad

Cabaña ED

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Lorena Troncoso Valencia

2018-01-01

Full Text Available Este proyecto denominado Cabaña Ed, de la arquitecta chilena Lorena Troncoso Valencia, es parte de una serie de obras emplazadas en la comuna de Pinto, Región de Ñuble de Chile. Zona de frondosa vegetación de árboles autóctonos y con fugas visuales hacia la cordillera de los Andes. La Cabaña Ed, donde predomina el uso de la madera, se integra muy sutilmente con ese entorno natural. Cabin ED, by the Chilean architect Lorena Troncoso Valencia, is part of a series of works located in the commune of Pinto, Ñuble Region, Chile. This area is characterized by lush vegetation of native trees and visual towards the Andes leaks. In this project the use of wood predominates, which is subtly integrated with the natural environment. In the edition of REVISTARQUIS 11, another project of the architect, located in that same zone of tourist development was presented.

Ecología trófica de Girella laevifrons (Pisces: Kyphosidae en zonas intermareales rocosas del norte de Chile afectadas y no afectadas por contaminantes derivados de la minería del cobre Trophic ecology of Girella laevifrons (Pisces: Kyphosidae in rocky intertidal zones of northern Chile affected an non-affected by copper mine tailings

Directory of Open Access Journals (Sweden)

JOSE MIGUEL FARIÑA

2000-03-01

Full Text Available La zonas intermareales de localidades de la costa norte de Chile afectadas por contaminantes derivados de la minería del cobre, presentan una diversidad de especies sésiles menor que las localidades no afectadas. Girella laevifrons es un pez altamente representado en zonas intermareales rocosas del norte de Chile. En el presente trabajo se analiza y compara la ecología trófica de esta especie, en relación con las diferencias en la composición de especies sésiles de sitios contaminados y no contaminados. Los resultados muestran diferencias significativas en la composición trófica de los ejemplares presentes en los sitios afectados y no afectados. Dentro de los sitios afectados, se observan diferencias en los tamaños y en las concentraciones de cobre corporales, las cuales pueden estar relacionadas directamente con la disponibilidad de alimento e indirectamente con interacciones con otros organismos intermarealesThe intertidal zone at several sites of the northern Chilean coast affected by copper mine tailings, shows a lower diversity of sessile species than the non-affected ones. Girella laevifrons is a fish highly represented in rocky intertidal shores of these sites. In this study we analized and compared, the dietary composition of this species and its relation with the intertidal sessile assemblages of contaminated and non-contaminated sites. The results show significant differences in the dietary composition of the fishes occurring in contaminated and non-contaminated sites. Within the contaminated sites, the differences in body sizes and in the body concentrations of copper could be related directly to the food availability and indirectly to the interactions with other intertidal species

Primer registro de Heliotropium amplexicaule (Heliotropiaceae) en Chile

OpenAIRE

Ibáñez, Sergio; Luebert, Federico; Gómez, Miguel

2011-01-01

The presence of the commonly known weed Heliotropium amplexicaule (Heliotropiaceae) is reported for Chile first time, from a collection recently made in Santiago. Its potential as weed in Chile is discussed in the context of the experience of other countries where the species has become naturalised.

Recent Discoveries of the Paijanense in The Upper Chicama, Moche and Virú Valleys, Northern Perú: New Perspectives on the First Hunter-Gatherers in the Andes of South America

OpenAIRE

Briceño, Jesús

2014-01-01

We present newly-registered Paiján sites in the interior and upper parts of the Chicama, Moche and Virú valleys, with strong tiesto the highland region. The research indicates that Paiján hunter-gatherers were not only a coastal group whose subsistence was basedon marine resources. They also occupied diverse ecological environments preferring springs with high mobility across the Andes and exploiting diverse resources, such as white-tail deer (Odocoileus virginianus) and raw materials for pro...

Estudio del campo ocupacional del traductor en Santiago de Chile (A Study of Opportunities for Professional Translators in Santiago, Chile).

Science.gov (United States)

Cabrera, Ileana; And Others

A study of translation as a profession in Chile covered two areas: a diagnostic study of the real need for literary, scientific, and technical translations, and a followup study of graduates of the translation degree program at the Catholic Pontifical University of Chile (Santiago). The analysis considered the relationship between the need for…

The Revolutionary Left and Terrorist Violence in Chile.

Science.gov (United States)

1986-06-01

Fraude Electoral Designada por la Facultad de Derecho de la Pontifica Universidad de Chile," in Libro Blanco del Cambio de Gobierno de Chile, Editorial...Chilean law, could not be invaded by the police. The MIR never became a formal political party. It completely rejected the electoral process

Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters

Science.gov (United States)

2007-05-01

Microbiology . All Rights Reserved. Temporal Analysis of Andes Virus and Sin Nombre Virus Infections of Syrian Hamsters Victoria Wahl-Jensen,1 Jennifer...Ye, C., J. Prescott , R. Nofchissey, D. Goade, and B. Hjelle. 2004. Neutralizing antibodies and Sin Nombre virus RNA after recovery from hantavirus

The TF1 Radio Astronomy Working Group in the Andean ROAD: goals and challenges for 2025

Science.gov (United States)

Chaparro Molano, G.

2017-07-01

Since the creation of the Andean Regional Office of Astronomy for Development (OAD) of the International Astronomical Union, one of the main goals has been to foster a scientific culture of radio astronomy in countries of the central and northern Andes (Bolivia, Colombia, Ecuador, Perú, and Venezuela). For this reason, Andean ROAD Task Force 1 (Research and Education in Universities) created the Radio Astronomy Working Group to set a path along which collaborative endeavors can grow and yield scientific results. The first official meeting of the Working Group took place in Bogotá, Colombia during the 2nd Astronomá en los Andes Workshop (2015) where scientists actively developing projects in radio astronomy set goals for the near future, such as improving mobility for researchers and students, developing collaborations in related areas such as engineering and data science, and building transnational collaborations aiming at developing VLBI across the countries of the Andean ROAD and beyond. In this poster, I present current projects and associated research groups (ROAS - Perú, SiAMo - Colombia, Alfa-Orion UTP - Colombia, RAIG - Chile) and discuss goalposts and current challenges in the development of transnational radioastronomical projects. As a case study, I present the development and early astronomical results of the privately funded UECCI 4m Radio Telescope for 21 cm line observations in Bogotá, Colombia.

La formación de anillos de crecimiento en Fissurella crassa en el norte de Chile

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Marta Bretos

1980-12-01

Full Text Available Growth discontinuity in molluscs result in the formation of rings on their shells. Two kind of rings may be formed: disturbance and growth rings. Growth rings can be used to determine the age of molluscs with long life span. For this, it is necessary to know how many growth rings are formed per year. It has been demonstrated experimentally, using marked specimens, that F. crassa forms two growth rings per year at Huayquique, Northern Chile. They are formed during winter and summer. Disturbance ring formation has also been observed as a result of sawing marks on their shells. A growth curve for this species is proposed on the basis of Walford's line.

Jazz en Chile: su historia y función social Jazz in Chile: its history and social function

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Álvaro Menanteau

2008-12-01

Full Text Available Este artículo presenta una visión general de la historia del jazz en Chile que destaca la función social de esta música y el cambio que tuvo a través del tiempo. Estos cambios se relacionaron con diferentes valoraciones de la práctica jazzística local. En un principio el jazz fue música popular masiva. Posteriormente fue valorado estéticamente por un segmento de élite, quienes eran profesionales en áreas no musicales y en muchos casos eran instrumentistas aficionados. En una tercera etapa, músicos profesionales asumieron la práctica del jazz como una plataforma para fusionar el lenguaje jazzístico con recursos tomados de la música tradicional chilena. Este tránsito del jazz en Chile está cruzado por factores socioeconómicos y estéticos, que se analizan en el trabajo.The article presents an overview of the history of jazz in Chile on the basis of the social function of jazz and the changes it has underwent over the years in terms of the valúes it has represented for Chilean society. Initially jazz was considered as mass popular music. Afterwards it was valued in aesthetic terms by a group belonging to the élite of Chilean society. Many of them belonged to non-music professions and in some cases were amateur musicians. Most recently professional musicians took up jazz as the basis for combining the jazz style with elements belonging to traditional music of Chile. This process in Chile is also influenced by social, economic and aesthetic aspects which are explored in this article.

The Native Fruit Geoffroea decorticans from Arid Northern Chile: Phenolic Composition, Antioxidant Activities and In Vitro Inhibition of Pro-Inflammatory and Metabolic Syndrome-Associated Enzymes

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Felipe Jiménez-Aspee

2017-09-01

Full Text Available The native tree Geoffroea decorticans (chañar grows in the arid lands of northern Chile. It has been used as a food plant since prehistoric times. Phenolic-enriched extracts (PEEs of Chilean chañar fruits were assessed for their chemical composition, antioxidant properties and inhibition of pro-inflammatory and metabolic syndrome-associated enzymes. Phenolic profiles were determined by HPLC-DAD-MS/MS. The PEEs of G. decorticans showed a strong effect towards the enzymes COX-1/COX-2, with inhibition percentages ranging from inactive to 92.1% and inactive to 76.0% at 50 µg PEE/mL, respectively. The IC50 values of the PEEs towards lipoxygenase and phospholipase A2 inhibitory activity were between 43.6–96.8 and 98.9–156.0 μg PEE/mL, respectively. Samples inhibited α-glucosidase (IC50 0.8–7.3 μg PEE/mL and lipase (9.9 to >100 μg PEE/mL. However, samples did not inhibit α-amylase. The HPLC-DAD-MS analysis of the PEEs allowed the tentative identification of 53 compounds, mainly flavonol glycosides and procyanidins. The procyanidin content of the Chilean G. decorticans pulp was positively correlated with the antioxidant activity and the inhibition of the enzyme α-glucosidase. These results indicate that the Chilean chañar fruit contains bioactive polyphenols with functional properties.

The state of solar energy resource assessment in Chile

Energy Technology Data Exchange (ETDEWEB)

Ortega, Alberto; Escobar, Rodrigo [Mechanical and Metallurgical Engineering Department, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, Macul, Santiago (Chile); Colle, Sergio [Laboratorios de Engenharia de Processos de Conversao e Tecnologia de Energia - LEPTEN, Mechanical Engineering Department, Universidade Federal de Santa Catarina, Florianopolis (Brazil); de Abreu, Samuel Luna [IFSC - Instituto Federal de Santa Catarina, Campus Sao Jose, Sao Jose - SC (Brazil)

2010-11-15

The Chilean government has determined that a renewable energy quota of up to 10% of the electrical energy generated must be met by 2024. This plan has already sparked interest in wind, geothermal, hydro and biomass power plants in order to introduce renewable energy systems to the country. Solar energy is being considered only for demonstration, small-scale CSP plants and for domestic water heating applications. This apparent lack of interest in solar energy is partly due to the absence of a valid solar energy database, adequate for energy system simulation and planning activities. One of the available solar radiation databases is 20-40 years old, with measurements taken by pyranographs and Campbell-Stokes devices. A second database from the Chilean Meteorological Service is composed by pyranometer readings, sparsely distributed along the country and available from 1988, with a number of these stations operating intermittently. The Chilean government through its National Energy Commission (CNE) has contracted the formulation of a simulation model and also the deployment of network of measurement stations in northern Chile. Recent efforts by the authors have resulted in a preliminary assessment by satellite image processing. Here, we compare the existing databases of solar radiation in Chile. Monthly mean solar energy maps are created from ground measurements and satellite estimations and compared. It is found that significant deviation exists between sources, and that all ground-station measurements display unknown uncertainty levels, thus highlighting the need for a proper, country-wide long-term resource assessment initiative. However, the solar energy levels throughout the country can be considered as high, and it is thought that they are adequate for energy planning activities - although not yet for proper power plant design and dimensioning. (author)

Feeding habits of four species of mesopelagic fishes from the Northern Chilean.

Science.gov (United States)

Oliva A, Eduardo; Ulloa H, Raúl; Bleck Z, Jorge

2006-06-01

The feeding habits of four species of mesopelagic fishes from northern Chile are described: Triphoturus mexicanus, Diogenichtys atlanticus, Vinciguerria lucetia and Cyclothone acclinidens. Samples were captured in September 1988 between 18 degrees 25' and 19 degrees 09'S in the South West Pacific. The quantitative and qualitative analyses of the stomach content showed that the species have a zooplanktophagous opportunistic behavior, mainly predating on Crustaceans, especially on Copepods. The evaluation of the trophic spectrum and diversity of T. mexicanus and C. acclinidens suggests that these are nictoepipelagic species, while D. atlanticus and V. lucetia would be typical mesopelagic.

Psicología comunitaria y políticas sociales en Chile Psicologia comunitaria e políticas sociais no Chile Community psychology and social policies in Chile

Directory of Open Access Journals (Sweden)

Jaime Alfaro Inzunza

2009-08-01

Full Text Available En este artículo analizamos la relación entre Psicología Comunitaria y políticas sociales, estableciendo la influencia de las políticas sociales sobre el desarrollo contemporáneo de la Psicología Comunitaria en Chile. Sostenemos que su consolidación como profesión se asocia estrechamente a la implementación de políticas sociales a partir de la década de los noventa y su conformación actual está condicionada y tensionada por las orientaciones de estas políticas. Se examina la evolución tanto de las políticas sociales como de la Psicología Comunitaria en Chile, los puntos de encuentro y las tensiones, de las que derivamos una serie de desafíos y proyecciones que examinamos en el presente artículo, con el objetivo de avanzar en la comprensión de esta relación.Este artigo investigou a relação entre a Psicologia Comunitária e as políticas sociais, estabelecendo a influência das políticas sociais sobre o desenvolvimento contemporâneo da Psicologia Comunitária no Chile. Afirmamos que a sua consolidação como profissão está intimamente associada à implementação de políticas sociais desde a década de noventa e sua formação atual está condicionada e tensionada pelas diretrizes dessas políticas. O estudo analisa a evolução das políticas sociais e da psicologia comunitária no Chile, os pontos de encontro e de tensão, dos quais se deriva uma série de desafios e projeções discutidos neste artigo com o objetivo de fazer avançar a compreensão desta relação.In this article we analyze the evolution of community psychology in Chile, and the influences of social policies in its development. We hold that its consolidation as a profession is closely associated to the implementation of social policies since the nineties, and its present conformation is determined and tightened by the orientation of these policies. From the evolution of social policies and Community Psychology in Chile we have come up with a series