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Sample records for deposit northern chile

  1. 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

  2. "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

  3. A genetic link between magnetite mineralization and diorite intrusion at the El Romeral iron oxide-apatite deposit, northern Chile

    Science.gov (United States)

    Rojas, Paula A.; Barra, Fernando; Reich, Martin; Deditius, Artur; Simon, Adam; Uribe, Francisco; Romero, Rurik; Rojo, Mario

    2018-01-01

    El Romeral is one of the largest iron oxide-apatite (IOA) deposits in the Coastal Cordillera of northern Chile. The Cerro Principal magnetite ore body at El Romeral comprises massive magnetite intergrown with actinolite, with minor apatite, scapolite, and sulfides (pyrite ± chalcopyrite). Several generations of magnetite were identified by using a combination of optical and electron microscopy techniques. The main mineralization event is represented by zoned magnetite grains with inclusion-rich cores and inclusion-poor rims, which form the massive magnetite ore body. This main magnetite stage was followed by two late hydrothermal events that are represented by magnetite veinlets that crosscut the massive ore body and by disseminated magnetite in the andesite host rock and in the Romeral diorite. The sulfur stable isotope signature of the late hydrothermal sulfides indicates a magmatic origin for sulfur (δ34S between - 0.8 and 2.9‰), in agreement with previous δ34S data reported for other Chilean IOA and iron oxide-copper-gold deposits. New 40Ar/39Ar dating of actinolite associated with the main magnetite ore stage yielded ages of ca. 128 Ma, concordant within error with a U-Pb zircon age for the Romeral diorite (129.0 ± 0.9 Ma; mean square weighted deviation = 1.9, n = 28). The late hydrothermal magnetite-biotite mineralization is constrained at ca. 118 Ma by 40Ar/39Ar dating of secondary biotite. This potassic alteration is about 10 Ma younger than the main mineralization episode, and it may be related to post-mineralization dikes that crosscut and remobilize Fe from the main magnetite ore body. These data reveal a clear genetic association between magnetite ore formation, sulfide mineralization, and the diorite intrusion at El Romeral (at 129 Ma), followed by a late and more restricted stage of hydrothermal alteration associated with the emplacement of post-ore dikes at ca. 118 Ma. Therefore, this new evidence supports a magmatic-hydrothermal model for the

  4. Stable isotope evidence for an atmospheric origin of desert nitrate deposits in northern Chile and southern California, U.S.A.

    Science.gov (United States)

    Böhlke, J.K.; Ericksen, G.E.; Revesz, K.

    1997-01-01

    Natural surficial accumulations of nitrate-rich salts in the Atacama Desert, northern Chile, and in the Death Valley region of the Mojave Desert, southern California, are well known, but despite many geologic and geochemical studies, the origins of the nitrates have remained controversial. N and O isotopes in nitrate, and S isotopes in coexisting soluble sulfate, were measured to determine if some proposed N sources could be supported or rejected, and to determine if the isotopic signature of these natural deposits could be used to distinguish them from various types of anthropogenic nitrate contamination that might be found in desert groundwaters. High-grade caliche-type nitrate deposits from both localities have ??15N values that range from -5 to +5???, but are mostly near 0???. Values of ??15N near 0??? are consistent with either bulk atmospheric N deposition or microbial N fixation as major sources of the N in the deposits. ??18O values of those desert nitrates with ??15N near 0??? range from about +31 to + 50??? (V-SMOW), significantly higher than that of atmospheric O2 (+ 23.5???). Such high values of ??18O are considered unlikely to result entirely from nitrification of reduced N, but rather resemble those of modern atmospheric nitrate in precipitation from some other localities. Assuming that limited modern atmospheric isotope data are applicable to the deposits, and allowing for nitrification of co-deposited ammonium, it is estimated that the fraction of the nitrate in the deposits that could be accounted for isotopically by atmospheric N deposition may be at least 20% and possibly as much as 100%. ??34S values are less diagnostic but could also be consistent with atmospheric components in some of the soluble sulfates associated with the deposits. The stable isotope data support the hypothesis that some high-grade caliche-type nitrate-rich salt deposits in some of the Earth's hyperarid deserts represent long-term accumulations of atmospheric deposition

  5. Trace Element Geochemistry of Magnetite and Accesory Phases from El Romeral Iron Oxide-Apatite Deposit, Northern Chile

    Science.gov (United States)

    Barra, F.; Rojas, P.; Reich, M.; Deditius, A.; Simon, A. C.

    2017-12-01

    Iron oxide-apatite (IOA) or "Kiruna-type" deposits are an important source of Fe, P, REE, among other essential elements for society. Three main hypotheses have been proposed to explain the genesis of these controversial deposits, which invoke liquid immiscibility, hydrothermal replacement or a magmatic-hydrothermal origin driven by flotation of magnetite-bubble pairs. Here we focus on the El Romeral, one of the largest IOA deposits located in the southernmost part of the Cretaceous Chilean Iron Belt. We combined SEM observations and EMPA analyses of magnetite, actinolite, pyrite, and apatite, with micro-Raman determinations of mineral inclusions within magnetite grains. Two textural types of magnetite were identified at El Romeral: (i) inclusion-rich magnetite (Mag I), and (ii) inclusion-poor magnetite (Mag II) that are commonly surrounding the inclusion-rich Mag I grains. Mag I is characterized by high V ( 2500-2800 ppm) and Ti (300-1000 ppm) contents with high-temperature mineral inclusions such as ilmenite, Ti-pargasite and clinochlore at depth, and quartz and phlogopite inclusions in shallower samples. These characteristics are consistent with a magmatic origin for Mag I. Inclusion-poor magnetite (Mag II) have high V (2400-2600 ppm) and lower Ti (70-200 ppm) contents than Mag I, which point to chemical changes of the mineralizing fluid(s). An increase in thermal gradient with depth is evidenced by the presence of high-temperature (low #Fe) actinolite, as well as F-rich apatite and pyrite with high Co:Ni (>1) in the deep zones. In contrast, lower Co:Ni ratios (<0.5) in pyrite and higher Cl contents in OH-rich apatite are detected in samples from shallower levels. This vertical chemical variation supports a magmatic-hydrothermal origin for the El Romeral deposit, and point to compositional changes driven by decompression of a magnetite-fluid suspension.

  6. Subduction zone guided waves in Northern Chile

    Science.gov (United States)

    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.

  7. 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

    Science.gov (United States)

    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

  8. 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.

  9. 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)

  10. 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

  11. Black carbon and other light-absorbing impurities in the Andes of Northern Chile

    Science.gov (United States)

    Rowe, P. M.; Cordero, R.; Warren, S. G.; Pankow, A.; Jorquera, J.; Schrempf, M.; Doherty, S. J.; Cabellero, M.; Carrasco, J. F.; Neshyba, S.

    2015-12-01

    Black carbon (BC) and other light-absorbing impurities in snow absorb solar radiation and thus have the potential to accelerate glacial retreat and snowmelt. In Chile, glaciers and seasonal snow are important sources of water for irrigation and domestic uses. In July 2015 (Austral winter) we sampled snow in the western Andes in a north-south transect of Chile from 18 S to 34 S. Most of the sampled snow had fallen during a single synoptic event, during 11-13 July. The snow was melted and passed through 0.4 micrometer nuclepore filters. Preliminary estimates indicate that (1) the ratio of BC to dust in snow increases going south from Northern to Central Chile, and (2) in snow sampled during the two weeks following the snowstorm, the impurities were concentrated in the upper 5 cm of snow, indicating that the surface layer became polluted over time by dry deposition.

  12. Isotopic composition and origin of the precipitation in Northern Chile

    International Nuclear Information System (INIS)

    Aravena, R.; Pena, H.; Grilli, A.; Pollastri, A.; Fuenzalida, H.

    1997-01-01

    Full text: A three years isotope data on precipitation collected in northern Chile show a very distinct pattern, with depleted δ 18 and -150/00 observed at high altitude stations, compared to δ 18 0 values ranging between - 10 and -6/00 measured at the lower altitude areas. The depleted δ 0 values observed in the high altitude area, the Altiplano, are related to different processes that affect the air masses as moved from the Atlantic, crossed the Amazon Basin (continental effect), ascend the Andes (altitude effect) and precipitated (convective effect) in the Altiplano. It is postulated that a second source of moisture, associated to air masses from the Pacific, explained the enriched isotopic values observed in the lower altitude areas. Similar isotopic pattern, documented in springs and groundwater, indicates that the rain data presented in this paper is an accurate representation of the long term behavior of the isotopic composition of the rain in northern Chile

  13. 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.

  14. Hydrogeomorphic Investigation of the 2015 Atacama Floods, Northern Chile

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  16. Isotopic composition and origin of the precipitation in Northern Chile

    International Nuclear Information System (INIS)

    Aravena, R.; Suzuki, O.; Pena, H.; Pollastri, A.; Fuenzalida, H.; Grilli, A.

    1999-01-01

    A 3 a data set of isotopes in precipitation from northern Chile show a very distinct pattern, with δ 18 O values ranging between -18 and -15per thousand at high altitude stations, compared to δ 18 O values between -10 and -6per thousand at the lower altitude areas. The 18 O-depleted values observed in the high altitude area, the Altiplano, are related to processes that affect the air masses that originated over the Atlantic, cross the Amazon Basin (continental effect), ascend the Andes (altitude effect) and precipitated (convective effect) in the Altiplano. It is postulated that a second source of moisture, associated with air masses from the Pacific, may contribute to the 18 O-enriched values observed in the lower altitude areas. Similar isotopic patterns are documented in springs and groundwater indicating that the data presented in this paper are an accurate representation of the long term behavior isotopic composition of rain in northern Chile. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  17. Isotopic composition and origin of the precipitation in Northern Chile

    Energy Technology Data Exchange (ETDEWEB)

    Aravena, R. [Department of Earth Sciences, University of Waterloo, Waterloo (Canada); Suzuki, O. [Exploracion y Desarrollo de Recursos Hidricos, Santiago (Chile); Pena, H. [Direccion General de Aguas, Ministerio de Obras Publicas, Santiago (Chile); Pollastri, A. [Comision Chilena de Energia Nuclear, Santiago (Chile); Fuenzalida, H. [Departamento de Geofisica, Universidad of Chile, Santiago (Chile); Grilli, A. [Empresa Metropolitana de Obras Sanitarias, Santiago (Chile)

    1999-06-01

    A 3 a data set of isotopes in precipitation from northern Chile show a very distinct pattern, with {delta}{sup 18}O values ranging between -18 and -15per thousand at high altitude stations, compared to {delta}{sup 18}O values between -10 and -6per thousand at the lower altitude areas. The {sup 18}O-depleted values observed in the high altitude area, the Altiplano, are related to processes that affect the air masses that originated over the Atlantic, cross the Amazon Basin (continental effect), ascend the Andes (altitude effect) and precipitated (convective effect) in the Altiplano. It is postulated that a second source of moisture, associated with air masses from the Pacific, may contribute to the {sup 18}O-enriched values observed in the lower altitude areas. Similar isotopic patterns are documented in springs and groundwater indicating that the data presented in this paper are an accurate representation of the long term behavior isotopic composition of rain in northern Chile. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  18. 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

  19. Oxygenation variability 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.

    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.

  20. 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

  1. 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)

  2. 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

  3. Uranium and thorium deposits of Northern Ontario

    International Nuclear Information System (INIS)

    Robertson, J.A.; Gould, K.L.

    1983-01-01

    This, the second edition of the uranium-thorium deposit inventory, describes briefly the deposits of uranium and/or thorium in northern Ontario, which for the purposes of this circular is defined as that part of Ontario lying north and west of the Grenville Front. The most significant of the deposits described are fossil placers lying at or near the base of the Middle Precambrian Huronian Supergroup. These include the producing and past-producing mines of the Elliot Lake - Agnew Lake area. Also included are the pitchblende veins spatially associated with Late Precambrian (Keweenawan) diabase dikes of the Theano Point - Montreal River area. Miscellaneous Early Precambrian pegmatite, pitchblende-coffinite-sulphide occurrences near the Middle-Early Precambrian unconformity fringing the Lake Superior basin, and disseminations in diabase, granitic rocks, alkalic complexes and breccias scattered throughout northern Ontario make up the rest of the occurrences

  4. Isotope hydrology and geochemistry of northern Chile groundwaters

    Directory of Open Access Journals (Sweden)

    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.

  5. Mental health of indigenous school children in Northern Chile.

    Science.gov (United States)

    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.

  6. 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.

  7. Geomorphological characterization of endorheic basins in northern Chile

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  9. Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile.

    Science.gov (United States)

    Whelley, Patrick L; Jay, J; Calder, E S; Pritchard, M E; Cassidy, N J; Alcaraz, S; Pavez, A

    Unconsolidated pyroclastic flow deposits of the 1993 eruption of Lascar Volcano, Chile, have, with time, become increasingly dissected by a network of deeply penetrating fractures. The fracture network comprises orthogonal sets of decimeter-wide linear voids that form a pseudo-polygonal grid visible on the deposit surface. In this work, we combine shallow surface geophysical imaging tools with remote sensing observations and direct field measurements of the deposit to investigate these fractures and their underlying causal mechanisms. Based on ground penetrating radar images, the fractures are observed to have propagated to depths of up to 10 m. In addition, orbiting radar interferometry shows that deposit subsidence of up to 1 cm/year -1 occurred between 1993 and 1996 with continued subsidence occurring at a slower rate thereafter. In situ measurements show that 1 m below the surface, the 1993 deposits remain 5°C to 15°C hotter, 18 years after emplacement, than adjacent deposits. Based on the observed subsidence as well as estimated cooling rates, the fractures are inferred to be the combined result of deaeration, thermal contraction, and sedimentary compaction in the months to years following deposition. Significant environmental factors, including regional earthquakes in 1995 and 2007, accelerated settling at punctuated moments in time. The spatially variable fracture pattern relates to surface slope and lithofacies variations as well as substrate lithology. Similar fractures have been reported in other ignimbrites but are generally exposed only in cross section and are often attributed to formation by external forces. Here we suggest that such interpretations should be invoked with caution, and deformation including post-emplacement subsidence and fracturing of loosely packed ash-rich deposits in the months to years post-emplacement is a process inherent in the settling of pyroclastic material.

  10. Uranium deposits: northern Denver Julesburg basin, Colorado

    International Nuclear Information System (INIS)

    Reade, H.L.

    1978-01-01

    The Fox Hills Sandstone and the Laramie Formation (Upper Cretaceous) are the host rocks for uranium deposits in Weld County, northern Denver Julesburg basin, Colorado. The uranium deposits discovered in the Grover and Sand Creek areas occur in well-defined north--south trending channel sandstones of the Laramie Formation whereas the sandstone channel in the upper part of the Fox Hills Sandstone trends east--west. Mineralization was localized where the lithology was favorable for uranium accumulation. Exploration was guided by log interpretation methods similar to those proposed by Bruce Rubin for the Powder River basin, Wyoming, because alteration could not be readily identified in drilling samples. The uranium host rocks consist of medium- to fine-grained carbonaceous, feldspathic fluvial channel sandstones. The uranium deposits consist of simple to stacked roll fronts. Reserve estimates for the deposits are: (1) Grover 1,007,000 lbs with an average grade of 0.14 percent eU 3 O 8 ,2) Sand Creek 154,000 lbs with an average grade of 0.08 percent eU 3 O 8 , and 3) The Pawnee deposit 1,060,000 lbs with an average grade of 0.07 percent eU 3 O 8 . The configuration of the geochemical cells in the Grover and Sand Creek sandstones indicate that uraniferous fluids moved northward whereas in the Pawnee sandstone of the Fox Hills uraniferous fluids moved southward. Precipitation of uranium in the frontal zone probably was caused by downdip migration of oxygcnated groundwater high in uranium content moving through a favorable highly carbonaceous and pyritic host sandstone

  11. 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.

  12. 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.

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    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 ...

  17. 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

  18. Paleozoic evolution of active margin basins in the southern Central Andes (northwestern Argentina and northern Chile)

    Science.gov (United States)

    Bahlburg, H.; Breitkreuz, C.

    The geodynamic evolution of the Paleozoic continental margin of Gondwana in the region of the southern Central Andes is characterized by the westward progression of orogenic basin formation through time. The Ordovician basin in the northwest Argentinian Cordillera Oriental and Puna originated as an Early Ordovician back-arc basin. The contemporaneous magmatic arc of an east-dipping subduction zone was presumably located in northern Chile. In the back-arc basin, a ca. 3500 meter, fining-up volcaniclastic apron connected to the arc formed during the Arenigian. Increased subsidence in the late Arenigian allowed for the accomodation of large volumes of volcaniclastic turbidites during the Middle Ordovician. Subsidence and sedimentation were caused by the onset of collision between the para-autochthonous Arequipa Massif Terrane (AMT) and the South American margin at the Arenigian-Llanvirnian transition. This led to eastward thrusting of the arc complex over its back-arc basin and, consequently, to its transformation into a marine foreland basin. As a result of thrusting in the west, a flexural bulge formed in the east, leading to uplift and emergence of the Cordillera Oriental shelf during the Guandacol Event at the Arenigian-Llanvirnian transition. The basin fill was folded during the terminal collision of the AMT during the Oclóyic Orogeny (Ashgillian). The folded strata were intruded post-tectonically by the presumably Silurian granitoids of the "Faja Eruptiva de la Puna Oriental." The orogeny led to the formation of the positive area of the Arco Puneño. West of the Arco Puneño, a further marine basin developed during the Early Devonian, the eastern shelf of which occupied the area of the Cordillera Occidental, Depresión Preandina, and Precordillera. The corresponding deep marine turbidite basin was located in the region of the Cordillera de la Costa. Deposition continued until the basin fill was folded in the early Late Carboniferous Toco Orogeny. The basin

  19. 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.

  20. 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.

  1. Constraints on sediment transfer from the Andes to the coast of northern Chile

    Science.gov (United States)

    Binnie, Steven; Liermann, Ariane; Dunai, Tibor; Dewald, Alfred; Heinze, Stefan

    2013-04-01

    While rates of denudation have been suggested as having the potential to link tectonic processes with climate in many settings, the roles that sediment transport must also play have been largely neglected. It is the transport, or not, of eroded material, not necessarily the rate at which that material is produced which is the critical factor in many models of tectonic-climatic interactions. The notable lack of sediment in sections of the Peru-Chile trench has been implicated as a key control of subduction zone processes and consequently Andean mountain building, but little empirical data on sediment transport in the region exists. Here, we present the initial results of a study aiming to constrain the westward transfer of sediment from the Andes Mountains to the Pacific Coast of northern Chile by using in situ-produced cosmogenic nuclides. Fluvial sediments were collected at the mouths of several large catchments between 19° S and 26° S, where they drain into the Pacific, and also from upstream locations within each catchment. Sample sites were selected in order to investigate the cosmogenic nuclide derived basin-averaged denudation rates of the western flank of the Andes, and to compare this with the cosmogenic nuclide concentrations of fluvial sediments further downstream where the catchments exit to the coast. A simplistic interpretation of the cosmogenic 10Be concentrations as denudation rates gives results varying between ~10 and 300 m/Myr. We would expect the most rapid erosion to occur on the steeper, wetter western Andean flank and for slower erosion to be recorded from the more gentle sloping, hyperarid/arid regions between the foothills of the Andes and the Pacific coast. This pattern is observed in some basins but in others the nuclide concentrations imply the opposite, with several-fold higher erosion rates measured for the large catchments sampled at the coast in comparison to their mountainous Andean headwaters. One explanation for this unusual

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

    Science.gov (United States)

    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.

  3. 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)

  4. Mass balance and hydrological contribution of glaciers in northern and central Chile

    Science.gov (United States)

    MacDonell, Shelley; Vivero, Sebastian; McPhee, James; Ayala, Alvaro; Pellicciotti, Francesca; Campos, Cristian; Caro, Dennys; Ponce, Rodrigo

    2016-04-01

    Water is a critical resource in the northern and central regions of Chile, as the area supports more than 40% of the country's population, and the regional economy depends on agricultural production and mining, which are two industries that rely heavily on a consistent water supply. Due to relatively low rates of rainfall, meltwater from snow and ice bodies in the highland areas provides a key component of the annual water supply in these areas. Consequently, accurate estimates of the rates of ablation of the cryosphere (i.e. snow and ice) are crucial for predicting current supply rates, and future projections. Whilst snow is generally a larger contributor of freshwater, during periods of drought, glaciers provide a significant source. This study aims to determine the contribution of glaciers to two catchments in northern and central Chile during a 2.5 year period, which largely consisted of extreme dry periods, but also included the recent El Niño event. This study combined field and modelling studies to understand glacier and rock glacier contributions in the Tapado (30°S), Yeso (33°S) catchments. In the field we undertook glaciological mass balance monitoring of three glaciers, monitored albedo and snow line changes using automatic cameras for three glaciers, measured discharge continuously at several points, installed six automatic weather stations and used thermistors to monitor thermal regime changes of two rock glaciers. The combination of these datasets where used to drive energy balance and hydrological models to estimate the contribution of ice bodies to streamflow in the two studied catchments. Over the course of the study all glaciers maintained a negative mass balance, however glaciers in central Chile lost more mass, which is due to the higher melt rates experienced due to lower elevations and higher temperatures. Areas free of debris generally contributed more to streamflow than sediment covered regions, and snow generally contributed more over

  5. Acid deposition in the northern hemisphere

    Energy Technology Data Exchange (ETDEWEB)

    Longhurst, J.W.S.; Green, S.E.; Lee, D.S.

    1987-02-01

    Examines the phenomenon of acid deposition: the distribution and magnitude of sources and its actual and potential direct and indirect effects on soils, forests and other vegetation; wildlife, freshwaters, materials and health. The wide range of technological and other controls that are available to reduce the emissions of pollutants contributing to the phenomenon is also examined and includes pre-combustion control of pollutants, removal during combustion and post-combustion control. Also considered are political responses to acidification, acid deposition monitoring in the United Kingdom and the treatment of acidified areas.

  6. The discovery and geophysical response of the Atlántida Cu-Au porphyry deposit, Chile

    Science.gov (United States)

    Hope, Matthew; Andersson, Steve

    2016-03-01

    The discovery of the Atlántida Cu-Au-Mo porphyry deposit, which is unconformably overlain by 25-80 m of gravels, is a recent example of exploration success under cover in a traditional mining jurisdiction. Early acquisition of geophysics was a key tool in the discovery, and in later guiding further exploration drilling throughout the life of the project. Detailed review of the geophysical response of the deposit, with respect to the distribution of lithologies and alteration, coupled with their petrophysical properties has allowed full characterisation, despite no exposure at the surface of host rock nor porphyry-style mineralisation. Data acquired over the project include induced polarisation, magnetotellurics, ground and airborne magnetics, ground-based gravimetry, and petrophysical sampling. The distribution of the key geological features of the deposit has been inferred via acquisition of petrophysical properties and interpretation of surface geophysical datasets. Magnetic susceptibility is influenced strongly by both alteration and primary lithology, whilst density variations are dominated by primary lithological control. Several studies have shown that electrical properties may map the footprint of the hydrothermal system and associated mineralisation, via a combination of chargeability and resistivity. These properties are observed in geophysical datasets acquired at surface and allow further targeting and sterilisation at the deposit and project scale. By understanding these geophysical characteristics in a geological context, these data can be used to infer distribution of lithological units, depth to exploration targets and the potential for high grade mineralisation. Future exploration will likely be increasingly reliant on the understanding of the surface manifestations of buried deposits in remotely acquired data. This review summarises the application and results of these principles at the Atlántida project of northern Chile. Geophysical data can be

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. Geochemistry of the Patricia Zn-Pb-Ag Deposit (paguanta, NE Chile)

    Science.gov (United States)

    Chinchilla Benavides, D.; Merinero Palomares, R.; Piña García, R.; Ortega Menor, L.; Lunar Hernández, R.

    2013-12-01

    The Patricia Zn-Pb-Ag ore deposit is located within the Paguanta mining project, situated at the northern end of the Andean Oligocene Porphyry Copper Belt of Chile. The sulfide mineralization occurs as W-E oriented veins hosted in volcanic rocks, mainly andesite (pyroclastic, ash and lavas), of Upper Cretaceous to Middle Tertiary age. The ore mineralogy (obtained by EMPA analyses) comprises in order of abundance, pyrite, sphalerite (5.5 - 10.89 wt % Fe, 9.8-19 % molar FeS and 0.52 wt % Cd), galena, arsenopyrite, chalcopyrite and Ag-bearing sulfosalts. The veins show a zoned and banded internal structure with pyrite at the edges and sphalerite in the center. The Ag occurs mostly as Ag-Cu-Sb sulfosalts, in order of abundance: series freibergite - argentotennantite -polybasite and stephanite. Other minor Ag phases such as argentite, pyrargirite and diaphorite were also identified. These Ag phases are typically associated with the base-metal sulfides. Freibergite occurs filling voids within sphalerite, chalcopyrite and at the contact between sphalerite and galena. Polybasite, stephanite, pyrargirite and argentite are mostly in close association with freibergite. In the case of diaphorite, it commonly occurs filling voids between galena crystals or as inclusions within galena. Some minor Ag-bearing sulfosalts are also identified between pyrite crystals. The alteration minerals are dominated by chlorite, illite and kaolinite. The gangue minerals consist of quartz and carbonates identified by XRD as kutnahorite. We obtained linear correlation statistically significant only for Ag, As Au, Cd, Cu, Pb, Sb and Zn and therefore we generated an enhanced scatter plot matrix of these elements. Bulk rock analyses (ICP/MS and XRF) of drill cores show that Ag is strongly and positively correlated with Pb and As, moderately with Cd, Sb, Au and Zn and weakly with Cu, while Au is moderately and positively correlated with Ag, As, Cd, Sb and Zn and weakly with Cu and Pb. These results

  10. 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...

  11. 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.

  12. 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.

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

    Science.gov (United States)

    Urzúa, Alfonso; Ferrer, Rodrigo; Canales Gaete, Valentina; Núñez Aragón, Dominique; Ravanal Labraña, Ivanna; Tabilo Poblete, Bárbara

    2017-03-01

    To establish the influence of acculturation strategies on quality of life, henceforth QoL. Using a cross-sectional design, two questionnaires were applied, the WHOQoL-BREF from the World Health Organization and Basabe's acculturation strategies. The questionnaires were applied to 853 Colombian and Peruvian immigrants living in Northern Chilean cities of Arica, Antofagasta and Santiago de Chile. In the psychological and social domains, as well as in the overall assessment of QoL, the most beneficial strategies are those where customs are maintained from the homeland, where "integration" then "separation" are the most beneficial. On the contrary, when the strategy for maintaining homeland customs is low, the QoL tends to be lower. The strategy of "marginalized" is associated with a lower QoL. Acculturation strategies mildly or moderately affect the psychological and social domains of quality of life as well as the overall assessment of QoL.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. 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

  18. 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.

  19. 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)

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

    Science.gov (United States)

    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.

  1. 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

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

    Directory of Open Access Journals (Sweden)

    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.

  3. A special issue devoted to gold deposits in northern Nevada: Part 2. Carlin-type Deposits

    Science.gov (United States)

    Hofstra, Albert H.; John, David A.; Theodore, Ted G.

    2003-01-01

    This is the second of two special issues of Economic Geology devoted to gold deposits in northern Nevada. Readers interested in a general overview of these deposits, their economic significance, their context within the tectonic evolution of the region, and synoptic references on each gold deposit type are directed to the preface of the first special issue (John et al., 2003). Volume 98, issue 2, contains five papers that address regional aspects important to the genesis of gold deposits in northern Nevada and five papers that present detailed studies of epithermal deposits and districts. All of the regional papers are pertinent to Carlin-type gold deposits, because they address the age of mineralization (Arehart et al., 2003), origin and evolutionary history of the northwest-striking mineral belts that localize many deposits (Grauch et al., 2003), nature of the middle and lower crust below these mineral belts (Howard, 2003), district- to deposit-scale stream sediment and lithogeochemical anomalies (Theodore et al., 2003), and stratigraphy and structure of a district located along a northeast-striking lineament (Peters et al., 2003).

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

    Science.gov (United States)

    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

  5. 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.

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

    OpenAIRE

    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...

  7. 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

    Directory of Open Access Journals (Sweden)

    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

  8. 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

  9. 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

  10. 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.

  11. 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)

  12. 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.

  13. 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.

  14. 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.

  15. Holocene tephra deposits in the northern Okinawa Trough

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The mineralogical and geochemical characteristics of sediments of Core CSH1, which was collected from the northern Okinawa Trough, indicate that large amounts of volcanic materials have deposited in the northern Okinawa Trough during the Holocene. On the basis of down-core variations in mineral and element contents of sediments, two layers in the uppermost section of Core CSH1 characterized by high quartz, Na2O, MnO, K2O, uranium contents and low contents of clay minerals, volatiles, Fe2O3, MgO, CaO and strontium, have been identified as the tephra deposits. Systematic grain-size measurements also suggest that sediments from the northern Okinawa Trough are made up of terrigenous materials and volcanic ashes with different proportion during the Holocene. The sediments of tephra layers in Core CSH1 show bi-modal patterns in grain-size distribution with modal grain-sizes of 74.3 and 7.81 μm,respectively. According to the radiocarbon dating on shells of zooplankton foraminifera, two tephra layers in Core CSH1, formed at 7 250 and 10 870 a BP (cal), approximately correspond to the K-Ah tephra [7 300 a BP (cal)] and the eruption of Kuju Volcano (12~10 ka BP), respectively.

  16. Fluxgate Magnetometer system mounted on UAS system: First field test at Dominga IOCG deposit, Chile

    Science.gov (United States)

    Yanez, G. A.; Banchero, L.; Marco, A.; Figueroa, R.

    2016-12-01

    With the support of Fundacion Chile (FCH) grant, we developed an airborne magnetic system (GeoMagDrone GFDAS) mounted on a UAS octodrone platform (DJI, S1000), based on a low cost/light-weight fluxgate magnetometer (FGM-301) and a robust/light-weight data logger for position, temperature, radar altimeter and 3 magnetic components at 16 Hz recording. Fluxgate magnetometer is hanging from the UAS platform at a distance of 2.5m where the EM noise is reduced to less than 2 nT. The whole geophysical system, including batteries, weights 650 gr., with an autonomy of 2 hours. Magnetometer calibration includes the 9 coefficients of amplitude, offset, and orthogonality, and temperature correction. We test the system over the IOCG deposit of Dominga-Chile, a magnetite ore (40%) (a block of 2x3 km with NS lines separated every 50m and a clearance of 40m, the mineral deposit buried 50-100m from the surface, where a ground magnetic survey was conducted previously. Ground conditions includes relatively rough topography with slopes of 10-20%, and some windy days. We use the digital terrain model SRTM30 to define the drape flight shape Average flight performance includes a mean speed of 35-40 km/hour, and an UAS battery consumption of 18-12 minutes depending on the wind conditions. A good correspondence was found between plan deployment and survey results in terms of line direction/separation/clearance. Line path were flown with errors less than 5 meters, whereas clearance of 40m was kept depending on the amount of control points used. The comparison between ground survey and GeoMagDrone results show a perfect match (anomaly amplitude/shape and noise envelope), validating in this way the system developed. Main concern for the productive application of this technology in unmanned geophysical platforms is the battery performance and the quality of digital terrain models to follow the topography.

  17. Wet deposition of poly- and perfluorinated compounds in Northern Germany

    International Nuclear Information System (INIS)

    Dreyer, Annekatrin; Matthias, Volker; Weinberg, Ingo; Ebinghaus, Ralf

    2010-01-01

    Twenty precipitation samples were taken concurrently with air samples at a northern German monitoring site over a period of 7 months in 2007 and 2008. Thirty four poly- and perfluorinated compounds (PFC) were determined in rain water samples by solid phase extraction and HPLC-MS/MS analysis. Seventeen compounds were detected in rain water with ΣPFC concentrations ranging from 1.6 ng L -1 to 48.6 ng L -1 . Perfluorooctanoate (PFOA) and perfluorobutanate (PFBA) were the compounds that were usually observed in highest concentrations. Calculated ΣPFC deposition rates were between 2 and 91 ng m -2 d -1 . These findings indicate that particle phase PFC are deposited from the atmosphere by precipitation. A relationship between PFC wet deposition and air concentration may be established via precipitation amounts. Trajectory analysis revealed that PFC concentration and deposition estimates in precipitation can only be explained if a detailed air mass history is considered. - Information on air mass history, meteorological conditions, and distribution of PFC sources is necessary to understand and estimate PFC concentrations and wet deposition.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  20. 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

  1. Gigantic landslides versus glacial deposits: on origin of large hummock deposits in Alai Valley, Northern Pamir

    Science.gov (United States)

    Reznichenko, Natalya

    2015-04-01

    As glaciers are sensitive to local climate, their moraines position and ages are used to infer past climates and glacier dynamics. These chronologies are only valid if all dated moraines are formed as the result of climatically driven advance and subsequent retreat. Hence, any accurate palaeoenvironmental reconstruction requires thorough identification of the landform genesis by complex approach including geomorphological, sedimentological and structural landform investigation. Here are presented the implication of such approach for the reconstruction of the mega-hummocky deposits formation both of glacial and landslide origin in the glaciated Alai Valley of the Northern Pamir with further discussion on these and similar deposits validity for palaeoclimatic reconstructions. The Tibetan Plateau valleys are the largest glaciated regions beyond the ice sheets with high potential to provide the best geological record of glacial chronologies and, however, with higher probabilities of the numerous rock avalanche deposits including those that were initially considered of glacial origin (Hewitt, 1999). The Alai Valley is the largest intermountain depression in the upper reaches of the Amudarja River basin that has captured numerous unidentified extensive hummocky deposits descending from the Zaalai Range of Northern Pamir, covering area in more than 800 km2. Such vast hummocky deposits are usually could be formed either: 1) glacially by rapid glacial retreat due to the climate signal or triggered a-climatically glacial changes, such as glacial surge or landslide impact, or 2) during the landslide emplacement. Combination of sediment tests on agglomerates forming only in rock avalanche material (Reznichenko et al., 2012) and detailed geomorphological and sedimentological descriptions of these deposits allowed reconstructing the glacial deposition in the Koman and Lenin glacial catchments with identification of two gigantic rock avalanches and their relation to this glacial

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

    Directory of Open Access Journals (Sweden)

    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

  3. 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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. 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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  9. 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 .

  10. 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...

  11. 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)

  12. Geomorphic effects and sedimentological record of flash floods in the Copiapó River salt marsh (Atacama coast, Northern Chile)

    Science.gov (United States)

    Abad, Manuel; Fernández, Rolando; Izquierdo, Tatiana

    2017-04-01

    The Copiapó River is located South of the Atacama Desert (northern Chile) that is considered one of the most arid areas of the planet. On March 25 2015 this fluvial valley experienced one the largest hydrometeorological events recorded in historical times. The rain, unusually high, favored the run off in fluvial channels and alluvial fans that were dry for decades and triggered the rise and overflow of the Copiapó River at different points along the valley causing severe damages. In this work, we realize a characterization of the geomorphic configuration of the Copiapó River before and after this event with the aim of analyzing the main changes produced in the river mouth, where and extent coastal wetland of high ecological value is developed. The geomorphological mapping show a drastic change in the river mouth with the development of forms related with the river overflow and the flooding of the coastal plain such as levees, activation of abandoned channels, flooding lagoons, widening and deepening of the main channel, foredune rupture and, more importantly, a large mud sheet that covers almost the 80% of the study area, including the wetland and the main coastal dune systems. Just a small area of the wetland, far from the main channel, was not affected by this process as it was protected by the levees formed during the first stages of the overflow. The mud flow facies are homogeneous and consist of a layer of massive silty sands with a maximum thickness of 10-75 cm overlied by 5-20 cm of clay with wavy top and carbonaceous rest. It also presents a wide development of mud cracks and salt crusts. At the same time, 4 stages have been differentiated along the event: 1) arrival to the wetland of the first surge that flows in the channel and flooding of the southern sector of the wetland; 2) flooding of the complete mouth area because of the peak discharge arrival and generalize overflow with and associate muddy facies deposition; 3) erosional stage of the channel

  13. 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

  14. 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

  15. 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

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    Miguel Avendaño

    2011-07-01

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

  19. 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

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

    Science.gov (United States)

    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.

  1. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  4. Recurrence of water bodies in the hyperarid core of the Atacama Desert - New insights into the Late Pleistocene paleoclimate history of Northern Chile

    Science.gov (United States)

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

    2017-12-01

    The Atacama Desert of northern Chile is regarded as the driest desert on Earth. Although still controversially discussed, overall arid to hyperarid conditions in the Atacama are thought to have persisted at least since the early Miocene, but were frequently punctuated by pluvial phases. The knowledge of past changes in humidity is strongly hampered by the fact that sediment records from the central Atacama Desert, which enable longer-scale precipitation reconstructions, are rare and mostly restricted to the Miocene/Pliocene or the late Pleistocene <50 kyrs. In this study, we focus on a sediment record from the hyperarid core of the Atacama Desert, derived from a tectonically blocked clay pan in the Coastal Cordillera (20°04'33.64"S, 69°55'01.75"W). This clay pan `Huara' has been initially investigated by a geophysical survey in spring 2015, followed by drilling of a short core (HU-III) covering the uppermost 4 m of sediment. Initial results of the ground penetrating radar (GPR) and horizontal to vertical (H/V) spectral ratio measurements indicate well-stratified sediment bodies in the basin with a maximum sediment infill of 30 ± 4 m. The chronology of core HU-III was established by a combination of optically stimulated luminescence (OSL) and paleomagnetic dating. The sedimentological and geochemical data of core HU-III as well as it's sediment geophysical properties indicate the primary accumulation of fine-grained sediments over the past ca. 50 kyrs, interpreted to be deposited under arid conditions with only sporadic precipitation. Intercalated coarser horizons indicate several periods of semiarid climate conditions, causing multiple phases of local alluvial deposition from the interior catchment area into the clay pan. The results are in agreement with a cosmogenic nuclide study from an adjacent meander system, indicating that the whole sediment sequence of the Huara clay pan covers the regional climate history of the past 500 - 700 kyrs.

  5. 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.

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

    International Nuclear Information System (INIS)

    Diaz, A.; Vivallo, W

    2001-01-01

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

  7. 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

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

    Directory of Open Access Journals (Sweden)

    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

  9. 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.

  10. The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile - Marine sources and diagenetic effects.

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    Friedrich Lucassen

    Full Text Available Seabird excrements (guano have been preserved in the arid climate of Northern Chile since at least the Pliocene. The deposits of marine organic material in coastal areas potentially open a window into the present and past composition of the coastal ocean and its food web. We use the stable isotope composition of nitrogen and carbon as well as element contents to compare the principal prey of the birds, the Peruvian anchovy, with the composition of modern guano. We also investigate the impact of diagenetic changes on the isotopic composition and elemental contents of the pure ornithogenic sediments, starting with modern stratified deposits and extending to fossil guano. Where possible, 14C systematics is used for age information. The nitrogen and carbon isotopic composition of the marine prey (Peruvian anchovy of the birds is complex as it shows strong systematic variations with latitude. The detailed study of a modern profile that represents a few years of guano deposition up to present reveals systematic changes in nitrogen and carbon isotopic composition towards heavier values that increase with age, i.e. depth. Only the uppermost, youngest layers of modern guano show compositional affinity to the prey of the birds. In the profile, the simultaneous loss of nitrogen and carbon occurs by degassing, and non-volatile elements like phosphorous and calcium are passively enriched in the residual guano. Fossil guano deposits are very low in nitrogen and low in carbon contents, and show very heavy nitrogen isotopic compositions. One result of the study is that the use of guano for tracing nitrogen and carbon isotopic and elemental composition in the marine food web of the birds is restricted to fresh material. Despite systematic changes during diagenesis, there is little promise to retrieve reliable values of marine nitrogen and carbon signatures from older guano. However, the changes in isotopic composition from primary marine nitrogen isotopic

  11. [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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  14. Fossil Microorganisms in Archaean deposits of Northern Karelia

    Science.gov (United States)

    Astafieva, M. M.; Hoover, R. B.; Rozanov, A. Y.; Vrevskiy, A. B.

    2005-01-01

    Newly found biomorphic microstructures from the Upper Archaean (lopian) rocks from Northern Karelia are described. The presence of various microorganisms of bacterial nature and even cyanobacteria (and possibly eukaryotic forms) is suggested. The necessity of employing methods of electron microscopy, as well as traditional methods, while studying the very early manifestations of life in Archaean and Early Proterozoic is noted.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. 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.

  17. 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.

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

    Science.gov (United States)

    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).

  19. Late Pleistocene glaciations of the arid subtropical Andes and new results from the Chajnantor Plateau, northern Chile

    Science.gov (United States)

    Ward, Dylan J.; Cesta, Jason M.; Galewsky, Joseph; Sagredo, Esteban

    2015-11-01

    The spatiotemporal pattern of glaciation along the Andes Mountains is an important proxy record reflecting the varying influence of global and regional circulation features on South American climate. However, the timing and extent of glaciation in key parts of the orogen, particularly the deglaciated arid Andes, are poorly constrained. We present new cosmogenic 10Be and 36Cl exposure ages for glacial features on and near the Chajnantor Plateau (23 °S). The new dates, although scattered due to cosmogenic inheritance, imply that the most recent extensive glacial occupation ended before or during the global Last Glacial Maximum (LGM). We discuss this new record in the context of published glacial chronologies from glacial features in Peru, Bolivia, and northern Chile rescaled using the latest cosmogenic 10Be production rate calibration for the tropical Andes. The results imply regionally synchronous moraine stabilization ca. 25-40 ka, 15-17 ka, and 12-14 ka, with the youngest of these moraines absent in records south of ∼20 °S, including in our new Chajnantor area chronology. This spatial pattern implicates easterly moisture in generating sufficient snowfall to glaciate the driest parts of the Andes, while allowing a role for westerly moisture, possibly modulated by the migration of the Southern Westerly Wind belt, in the regions near and south of the Atacama Desert.

  20. 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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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)

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Sedimentology and preservation of aeolian sediments on steep terrains: Incipient sand ramps on the Atacama coast (northern Chile)

    Science.gov (United States)

    Ventra, Dario; Rodríguez-López, Juan Pedro; de Boer, Poppe L.

    2017-05-01

    The origin of topographically controlled aeolian landforms in high-relief settings is difficult to synthesize under general models, given the dependence of such accumulations on local morphology. Quaternary sand ramps have been linked to palaeoclimate, regional geomorphology and wind patterns; however, controls on the early development and preservation of such landforms are poorly known. This study describes the morphology and sedimentology of complex sedimentary aprons along steep coastal slopes in the Atacama Desert (Chile). Direct slope accessibility and continuous stratigraphic exposures enable comparisons between active processes and stratigraphic signatures. Stratigraphic facies distribution and its links with patterns of aeolian deposition show that the preservation of wind-laid sediments depends on the morphology and processes of specific slope sectors. The spatial organization of runoff depends on bedrock configuration and directly controls the permanence or erosion of aeolian sediment. The occurrence of either water or mass flows depends on the role of aeolian fines in the rheology of flash floods. In turn, the establishment of a rugged surface topography controlled by patterns of mass-flow deposition creates local accommodation for aeolian fines, sustaining the initial aggradation of a colluvial-aeolian system. By contrast, slopes subject to runoff develop a thin, extensive aeolian mantle whose featureless surface is subject mostly to sediment bypass down- and across-slope; the corresponding stratigraphic record comprises almost exclusively thin debris-flow and sheetflood deposits. Slope morphology and processes are fundamental in promoting or inhibiting aeolian aggradation in mountain settings. Long-term sand-ramp construction depends on climate and regional topography, but the initial development is probably controlled by local geomorphic factors. The observed interactions between wind and topography in the study area may also represent a process

  6. Discussion on prospecting potential for rich uranium deposits in Xiazhuang uranium ore-field, northern Guangdong

    International Nuclear Information System (INIS)

    Wu Lieqin; Tan Zhengzhong

    2004-01-01

    Based on analyzing the prospecting potential for uranium deposits in Xiazhuang uranium ore field this paper discusses the prospecting for rich uranium deposits and prospecting potential in the region. Research achievements indicate: that the Xiazhuang ore-field is an ore-concentrated area where uranium has been highly enriched, and possesses good prospecting potential and perspective, becoming one of the most important prospecting areas for locating rich uranium deposits in northern Guangdong; that the 'intersection type', the alkaline metasomatic fractured rock type and the vein-group type uranium deposits are main targets and the prospecting direction for future uranium prospecting in this region

  7. Risk factors for mercury exposure of children in a rural mining town in northern Chile.

    Directory of Open Access Journals (Sweden)

    Johan Ohlander

    Full Text Available Traditional gold mining is associated with mercury exposure. Especially vulnerable to its neurotoxic effects is the developing nervous system of a child. We aimed to investigate risk factors of mercury exposure among children in a rural mining town in Chile.Using a validated questionnaire distributed to the parents of the children, a priori mercury risk factors, potential exposure pathways and demographics of the children were obtained. Mercury levels were measured through analyzing fingernail samples. Logistic regression modeling the effect of risk factors on mercury levels above the 75(th percentile were made, adjusted for potential confounders.The 288 children had a mean age of 9.6 years (SD = 1.9. The mean mercury level in the study population was 0.13 µg/g (SD 0.11, median 0.10, range 0.001-0.86 µg/g. The strongest risk factor for children's odds of high mercury levels (>75(th percentile, 0.165 µg/g was to play inside a house where a family member worked with mercury (OR adjusted 3.49 95% CI 1.23-9.89. Additionally, children whose parents worked in industrial gold mining had higher odds of high mercury levels than children whose parents worked in industrial copper mining or outside mining activities.Mercury exposure through small-scale gold mining might affect children in their home environments. These results may further help to convince the local population of banning mercury burning inside the households.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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

  11. New paleoparasitological investigations from the pre-inca to hispanic contact period in northern Chile.

    Science.gov (United States)

    de Souza, Mônica Vieira; da Silva, Lucélia Guedes Ribeiro; Silva-Pinto, Verónica; Mendez-Quiros, Pablo; de Miranda Chaves, Sergio Augusto; Iñiguez, Alena Mayo

    2018-02-01

    Paleoparasitological studies have demonstrated that changes in environment or culture are reflected in the patterns of parasitic infection diseases in populations worldwide. The advent of agriculture and animal domestication, with its accompanying reduction in human mobility and expanding population involves changes in or emergence of, parasites, the so-called first epidemiological transition. Cultural processes related to territory occupation contribute to both loss and acquisition of parasites. The archaeological site Lluta 57 in the Lluta Valley, Chile, provides a chronology of the transition from the pre-Inca or Late Intermediate Period (LIP), through the Late or Inca Period (LP), to the Hispanic Contact Period (HCP), providing the possibility of evaluating this epidemiological transition. The aim of this study was to conduct a paleoparasitological investigation of to gain insight into the dynamics of parasitism in Lluta people throughout the Inca expansion. Fourteen human coprolites from the three periods were rehydrated, submitted to spontaneous sedimentation, and examined by light microscopy for the presence of intestinal parasite eggs, pollen grains, and micro-remains. Eggs of four parasites: Enterobius vermicularis, Trichostrongylus sp., Trichuris sp., and Eimeria macusaniensis were recovered. Frequency, diversity, and number of parasite eggs per sample increased over the studied time period. Trichostrongylus sp. and E. macusaniensis were recorded in the region for the first time. Enterobius vermicularis eggs, absent in the LIP, were present as a hyper-infection in LP. The presence of E. macusaniensis is likely related to exploitation of llamas, which were used for food and transport and as sacrificial offerings. The paleobotanical analysis revealed ten families of pollen grains, as well as phytoliths and floral remains. In contrast to parasitological results, a diachronic pattern was not detected. Evolution of the settlements, with the advent of larger

  12. REE characteristics and uranium metallogenesis of sandstone-type uranium deposits in northern Sichuan

    International Nuclear Information System (INIS)

    Zhu Xiyang; Wang Yunliang; Wang Zhichang; Zhang Chengjiang

    2004-01-01

    On the basis of the analysis of a large number of samples at sandstone-type uranium deposits in northern Sichuan, this paper analyses the REE composition of country rocks, ores, calcite-veins and uranium minerals, and systematically summarizes their REE geochemical characteristics, and discusses variation regularity of REE during depositional and diagenetic processes. By comparing these characteristics with those of typical hydrothermal volcanics-type and metamorphic rock type uranium deposits both at home and abroad, authors suggest that sandstone-type uranium deposits in northern Sichuan are characterized by REE geochemical features of hydrothermal reworking metallogenesis, the uranium mineralization has experienced two stages: the diagenetic preconcentration and the concentration of hydrothermal reworking

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

    Science.gov (United States)

    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.

  14. 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.

  15. 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.

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

    Science.gov (United States)

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

    2016-01-01

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

  17. Effect of coastal urbanization on sandy beach coleoptera Phaleria maculata (Kulzer, 1959) in northern Chile.

    Science.gov (United States)

    González, Sergio A; Yáñez-Navea, Katherine; Muñoz, Mauricio

    2014-06-15

    The beetle Phaleria maculata is a common inhabitant of the upper intertidal fringe of Chilean beaches. Anthropogenic intervention in coastal areas has increased intensely, leading to changes in the flora and fauna of sandy beaches. To examine the impact of human activities on P. maculata, we studied several beaches along the northern Chilean coast. Beaches were characterized based on morphodynamics and the level of intervention, leading to the estimation of an "Urbanization Index" based on various indicators. The analysis showed a significant inverse correlation between the rate of urbanization and night sky quality. Larval and adult beetles were almost absent on beaches with high levels of urbanization. The results of simple and multiple correlations based on nMDS ordination showed an inverse relationship between increases in urbanization and the abundance of beetles. Because darkling beetles are very sensitive to human interventions on sandy beaches, we suggest that they are ideal indicator organisms for the health of these environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

    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.

  19. Submarine fans and associated deposits in the Lower Tertiary of Guipuzcoa (Northern Spain)

    NARCIS (Netherlands)

    Vliet, van A.

    1982-01-01

    The Lower Tertiary outcrop along the coast of Guipuzcoa, northern Spain, consists exclusively of deep-marine sediments, deposited in a narrow elongated (ESE-WNW) basin. The early Tertiary sedimentary history of this basin can be described in terms of three main phases:

    - a phase of

  20. Biomass burning in eastern Europe during spring 2006 caused high deposition of ammonium in northern Fennoscandia

    DEFF Research Database (Denmark)

    Karlsson, Per Erik; Ferm, Martin; Pihl Karlsson, Gunilla

    2013-01-01

    High air concentrations of ammonium were detected at low and high altitude sites in Sweden, Finland and Norway during the spring 2006, coinciding with polluted air from biomass burning in eastern Europe passing over central and northern Fennoscandia. Unusually high values for throughfall deposition...... of ammonium were detected at one low altitude site and several high altitude sites in north Sweden. The occurrence of the high ammonium in throughfall differed between the summer months 2006, most likely related to the timing of precipitation events. The ammonia dry deposition may have contributed to unusual...... visible injuries on the tree vegetation in northern Fennoscandia that occurred during 2006, in combination with high ozone concentrations. It is concluded that long-range transport of ammonium from large-scale biomass burning may contribute substantially to the nitrogen load at northern latitudes. © 2013...

  1. Description of extreme-wave deposits on the northern coast of Bonaire, Netherlands Antilles

    Science.gov (United States)

    Watt, Steven G.; Jaffe, Bruce E.; Morton, Robert A.; Richmond, Bruce M.; Gelfencaum, Guy

    2010-01-01

    To develop a better understanding of the origins of extreme-wave deposits and to help assess the potential risk of future overwash events, a field mapping survey was conducted in November 2006 on the northern coast of Bonaire, Netherlands Antilles. Deposits were mapped and analyzed to help develop a systematic sedimentological approach to distinguish the type of extreme-wave event (tsunamis or storms) or combination of events that formed and modified the deposits over time. Extreme-wave deposits on the northern coast of Bonaire between Boka Onima and Boka Olivia have formed sand sheets, poly-modal ridge complexes, and boulder fields on a Pleistocene limestone platform 3?8 meters above sea level. The deposits exhibit characteristics that are consistent with both large storm and tsunami processes that often overlap one another. Sand sheets occur as low-relief features underlying and incorporated with boulder field deposits. The seaward edge of ridge complexes are deposited up to 70 m from the shoreline and can extend over 200 m inland. Over 600 clasts were measured in fields and range in size from coarse gravel to fine block, weigh up to 165 metric tons, and are placed over 280 m from the shoreline. Our analyses indicate that the deposits may have been produced by a combination of hurricane and tsunami events spanning 10s to 1000s of years. Comparing the different deposit morphologies between study sites highlights the importance of shoreline orientation to the distribution of extreme-wave deposits onshore. However, further investigation is required to fully understand the processes that have produced and modified these deposits over time.

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

    Science.gov (United States)

    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

  3. Os isotopes and cooper sources for stratiform (mantos) cooper deposits of Chile

    International Nuclear Information System (INIS)

    Munizaga, Francisco; Ruiz, Joaquin; Freydier, Claire

    1998-01-01

    The sources of copper have been determined by studying trace elements osmium and rhenium as well as osmium isotope ratio in copper-bearing porphyry of Chuquicamata, el Teniente and Andacollo and in the stratiform copper deposits of Mantos Blancos, El Soldado, Cerro Negro and Talcuna

  4. Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China

    Science.gov (United States)

    Pan, Y. P.; Wang, Y. S.

    2015-01-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatiotemporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at 10 sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites, while the wet deposition exhibited less spatial variation. In addition, the seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for potassium, nickel, arsenic, lead, zinc, cadmium, selenium, silver and thallium, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution of the particles. We found that atmospheric inputs of copper, lead, zinc, cadmium, arsenic and

  5. The specifics of operating minor deposits (as given by the examples of gas condensate deposits of the Northern Caucasus

    Directory of Open Access Journals (Sweden)

    Р. А. Гасумов

    2016-08-01

    Full Text Available One of the most important directions in upgrading well productivity in the process of mining hydrocarbons consists in fighting with salt formation and salt deposition. Solving that problem becomes especially actual when operating deposits that are in their final stage of exploitation in complex mining and geological conditions accompanied by deposition of salts in the well foot area of oil bed and their sedimentation on the sub-surface and surface equipment. It provokes a drop in well productivity and results in off-schedule repair works. Specifics are considered of exploiting minor gas condensate deposits of the Northern Caucasus that are operated under complicated mining and geological conditions of anomalously high bed pressures, high temperatures, strong depressions on the beds and inflow of mineralized water from water saturated seams.Processes are studied of salt deposition from heavy hydrocarbons in the well foot and the bed area surrounding it. Water sample analyses data from different wells have demonstrated that the main salts carrier is the associated water, and the principal sedimenting agents are corrosion products, as confirmed by the results of microscopic studies. The dynamics is presented of salt deposition in the “well foot – wellhead – separator” system retrieved from the results of studies of reaction products in the well foot zone of oil bed.It is demonstrated that the efficiency of struggling with salt deposition in the course of mining hydrocarbons depends on comprehensive approach to the problem, the principal thrust lying with prevention of such deposition.Possible ways are considered to prevent precipitation of ferric compounds in the course of operating gas condensate wells, a way is suggested to intensify gas inflow.

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

    Science.gov (United States)

    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

  7. Diagenesis of Permian alluvial fan deposits of Northern Switzerland

    International Nuclear Information System (INIS)

    Bluem, W.

    1987-01-01

    Fine-grained sandstones of Permian alluvial fan deposits from three Nagra boreholes (Weiach, Riniken, Kaisten) and an exploration well, drilled at Wintersingen are clast supported, moderately sorted arkosic greywackes containing typically 2-20 % clayey matrix. Petrographic studies indicate that the origin of this clayey matrix is postdepositional. Mechanical infiltration of fines and diagenetic reddening of detrital and authigenic iron oxides are the earliest recorded events. Additionally, nodular calcites of calcrete origin and fibrous illitic clays are also ascribed to the eogenetic environment. The present strong compaction fabric results from general lack of eogenetic framework supporting cements. During mesogenesis, secondary porosity was generated through partial removal of early calcite. At the same time, a first generation of syntaxial quartz cementation and a subsequent fibrous illite authigenesis took place. Leaching of detrital K-feldspars post-dating compaction is recorded throughout the studied boreholes. The following burial diagenetic events differ between the various boreholes: in Weiach and Wintersingen kaolinite, illite, prismatic quartz and ankerite/siderite are recorded; in Riniken K-feldspar, illite, prismatic quartz and dolomite developed; whilst in Kaisten K-feldspar and microcrystalline quartz-cement dominate. These differences reflect the chemistry, pH and ionic strength of the pore fluids. Filling of veins by dolomite/ankerite, iron-rich and subsequent iron-poor calcite is the latest recorded event. (author) 21 refs., 10 figs., 1 tab

  8. A genetic model based on evapoconcentration for sediment-hosted exotic-Cu mineralization in arid environments: the case of the El Tesoro Central copper deposit, Atacama Desert, Chile

    Science.gov (United States)

    Fernández-Mort, A.; Riquelme, R.; Alonso-Zarza, A. M.; Campos, E.; Bissig, T.; Mpodozis, C.; Carretier, S.; Herrera, C.; Tapia, M.; Pizarro, H.; Muñoz, S.

    2017-12-01

    Although the formation of exotic-Cu deposits is controlled by multiple factors, the role of the sedimentary environment has not been well defined. We present a case study of the El Tesoro Central exotic-Cu deposit located in the Atacama Desert of northern Chile. This deposit consists of two mineralized bodies hosted within Late Cenozoic gravels deposited in an arid continental environment dominated by alluvial fans with sub-surficial ponded water bodies formed at the foot of these fans or within the interfan areas. Both exotic-Cu orebodies mostly consist of chrysocolla, copper wad, atacamite, paratacamite, quartz, opal, and calcite. The most commonly observed paragenesis comprises chrysocolla, silica minerals, and calcite and records a progressive increase in pH, which is notably influenced by evaporation. The results of stable isotope analyses (δ13C and δ18O) and hydrogeochemical simulations confirm that evapoconcentration is the main controlling factor in the exotic-Cu mineralization at El Tesoro Central. This conclusion complements the traditional genetic model based on the gradual neutralization of highly oversaturated Cu-bearing solutions that progressively cement the gravels and underlying bedrock regardless of the depositional environment. This study concludes that in exotic-Cu deposits formed relatively far from the source, a favorable sedimentary environment and particular hydrologic and climatic conditions are essential to trap, accumulate, evapoconcentrate, neutralize and saturate Cu-bearing solutions to trigger mineralization. Thus, detailed sedimentological studies should be incorporated when devising exploration strategies in order to discover new exotic-Cu resources, particularly if they are expected to have formed relatively far from the metal sources.

  9. 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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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

  11. Evolution of Mars’ Northern Polar Seasonal CO2 deposits: variations in surface brightness and bulk density

    Science.gov (United States)

    Mount, Christopher P.; Titus, Timothy N.

    2015-01-01

    Small scale variations of seasonal ice are explored at different geomorphic units on the Northern Polar Seasonal Cap (NPSC). We use seasonal rock shadow measurements, combined with visible and thermal observations, to calculate density over time. The coupling of volume density and albedo allows us to determine the microphysical state of the seasonal CO2 ice. We find two distinct endmembers across the NPSC: 1) Snow deposits may anneal to form an overlying slab layer that fractures. These low density deposits maintain relatively constant densities over springtime. 2) Porous slab deposits likely anneal rapidly in early spring and fracture in late spring. These high density deposits dramatically increase in density over time. The endmembers appear to be correlated with latitude.

  12. 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

    Directory of Open Access Journals (Sweden)

    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

  13. 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

  14. 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.

  15. Multiple origins of large hummock deposits in Alai Valley, Northern Pamir: Implications for palaeoclimate reconstructions

    Science.gov (United States)

    Reznichenko, N. V.; Andrews, G. R.; Geater, R. E.; Strom, A.

    2017-05-01

    This paper interprets the origin of several of the largest hummocky landform assemblages in the Alai Valley, Northern Pamir - a formerly glaciated intermontane depression. The vast hummocky deposits in the Koman-Suu and Achik-Tash river catchments are found to be of two contrasting modes of formation: glacial hummocks deposited during Koman and Lenin Glaciers withdraw and avalanche hummocks produced during catastrophic Koman and Lenin rock avalanches. The origins of the deposits we assessed through remote and field-based geomorphological mapping, as well as sedimentological investigations, which included clast analysis and the identification of micro-scale agglomerates indicative of rock avalanche emplacement. Both the Koman and Lenin rock avalanches were large, catastrophic events (with run-outs of 34 and 24 km, respectively, and a volume over 1 × 109 m3 each) that occurred subsequent to glacier withdrawal from the area. The complex conditions on the moment of the rock avalanche emplacement promoted unusual deposits geomorphology and extensive run-outs. The landslide landforms formed over the pre-existing glacial hummocks and fluvial deposits, and are geomorphologically and sedimentologically distinct from the larger glacial hummocks. The reconstruction of this sequence of events has implications for how hummock dating should be interpreted. This research illustrates large scale catastrophic landsliding in the glacial environment, and adds to the ongoing debate about the misidentification of rock avalanche deposits as of glacial origin, and their relevance to palaeoclimatological and palaeoseismological reconstructions.

  16. 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

  17. 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

    Directory of Open Access Journals (Sweden)

    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

  18. Geomorphological analysis, monitoring and modeling of large rock avalanches in northern Chile (Iquique area) for regional hazard assessment.

    Science.gov (United States)

    Yugsi Molina, F. X.; Hermanns, R. L.; Crosta, G. B.; Dehls, J.; Sosio, R.; Sepúlveda, S. A.

    2012-04-01

    mapped characterized by well defined lateral levees and clear internal morphological features (ridges and furrows, hummocks). Rock avalanche run out simulations have been carried out to back analyze the sites using DAN 3D and a 3 m pixel resolution digital elevation model (DEM) obtained from stereoscopic Geoeye-1 images to assess parameters that controlled propagation mechanism and impact area extent of the events. The older lobes were dated by radiocarbon methods. Results indicate ages higher than 40,000 yr BP for the northern site. The second site could only be dated relatively with an underlying terrace that resulted older than the age limit of radiocarbon dating (43.500 yr BP). All the deposits are positioned well above (40-70 m) the present sea level rise, and at the reported uplift rates for the area, they could be associated to events older than some hundreds of thousand years. A more complete record of the failure history of the sites will be obtained when results of cosmogenic nuclides (CN) and luminescence dating will become available later this year. Several other smaller rock avalanches have been mapped in the study area. Satellite-based radar interferometry (InSAR) was performed using ERS-1 and ERS-2 scenes from 1995-2000 as well as ENVISAT ASAR scenes from 2004-2010. Both datasets show only small deformation in the area. This deformation includes sliding of small surficial slope deposits and subsidence apparently due to local groundwater withdrawal. No deformation of bedrock along the escarpment edge is observed. Results show that only major rock avalanches could reach the main access roads to Iquique and currently no large slope segments show signs of large displacement rates. Moreover, there is no strong correlation between M > 8 earthquakes return periods and age of the dated deposits, which implies that large rock avalanches could have been triggered by other factors. Hence, from a hazard and risk perspective, it is unlikely that large rock avalanches

  19. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. 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

    Directory of Open Access Journals (Sweden)

    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.

  2. Occurrence and dry deposition of organophosphate esters in atmospheric particles over the northern South China Sea.

    Science.gov (United States)

    Lai, Senchao; Xie, Zhiyong; Song, Tianli; Tang, Jianhui; Zhang, Yingyi; Mi, Wenying; Peng, Jinhu; Zhao, Yan; Zou, Shichun; Ebinghaus, Ralf

    2015-05-01

    Nine organophosphate esters (OPEs) in airborne particles were measured during a cruise campaign over the northern South China Sea (SCS) from September to October 2013. The concentration of the total OPEs (∑OPEs) was 47.1-160.9 pg m(-3), which are lower than previous measurements in marine atmosphere environments. Higher OPE concentrations were observed in terrestrially influenced samples, suggesting that OPE concentrations were significantly influenced by air mass transport. Chlorinated OPEs were the dominant OPEs, accounting for 65.8-83.7% of the ∑OPEs. Tris-(2-chloroethyl) phosphate (TCEP) was the predominant OPE compound in the samples (45.0±12.1%), followed by tris-(1-chloro-2-propyl) phosphates (TCPPs) (28.8±8.9%). Dry particle-bound deposition fluxes ranged from 8.2 to 27.8 ng m(-2) d(-1) for the ∑OPEs. Moreover, the dry deposition input of the ∑OPEs was estimated to be 4.98 ton y(-1) in 2013 in a vast area of northern SCS. About half of the input was found to relate to air masses originating from China. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Two coarse pyroclastic flow deposits, northern Mono-Inyo Craters, CA

    Science.gov (United States)

    Dennen, R. L.; Bursik, M. I.; Stokes, P. J.; Lagamba, M.; Fontanella, N.; Hintz, A. R.; Jayko, A. S.

    2010-12-01

    -out distance of the Panum BAF is smaller than previously reported. Thus, there are multiple, coarse pyroclastic flow-like deposits at the northern end of the Mono-Inyo Craters, reflecting multiple phases of dome destruction. The lower blast deposit is proposed to be a blast event predating the Panum eruption, possibly originating from Pumice Pit. The Panum BAF consists of three main facies, formed by three separate, sequential events. A debris avalanche deposited a train of jigsaw clasts along a narrow path, followed by a block and ash flow that spread material over a wider region. Finally, molten rhyolite was exposed by the earlier events, resulting in rapid foam expansion and creation of a bread crusted reticulite-bearing facies.

  4. Stable isotope evidence for formation from magmatic fluids of the mineralized breccias in the Los Bronces and El Teniente copper deposits, Central Chile

    International Nuclear Information System (INIS)

    Skewes, M.A; Arevalo, A; Holmgren, C.; Stern, C.R

    2001-01-01

    The giant Miocene and Pliocene Rio Blanco-Los Bronces (Warnaars et al., 1985; Serrano et al., 1996; Vargas et al., 1999) and El Teniente (Camus, 1975; Cuadra, 1986; Skewes and Arevalo, 2000) copper deposits of central Chile are among the largest copper deposits in the world. Hypogene copper ore is more significant than supergene ore in these deposits, and most of the hypogene copper occurs in the matrix of multiple clusters of breccias (Skewes and Stern, 1994; 1995). The origin of the large mineralized breccia pipes in these and other Andean copper deposits has been attributed to the explosive expansion of magmatic aqueous fluids derived from cooling plutons (Emmons, 1938; Kents, 1964; Warnaars et al., 1985; Sillitoe, 1985; Skewes and Stern, 1994, 1995). Warnaars et al. (1985) and Skewes and Stern (1996) suggested that mineral deposition in the matrix of these breccias took place by the rapid cooling of the same magmatic fluids that generated the brecciation. Highly saline, high-temperature magmatic fluid inclusions occur in quartz and tourmaline in the matrix of these breccias (Holmgren et al., 1988; Vargas et al., 1999; Skewes et al., 2001) (au)

  5. Study of southern CHAONAN sag lower continental slope basin deposition character in Northern South China Sea

    Science.gov (United States)

    Tang, Y.

    2009-12-01

    Northern South China Sea Margin locates in Eurasian plate,Indian-Australia plate,Pacific Plates.The South China Sea had underwent a complicated tectonic evolution in Cenozoic.During rifting,the continental shelf and slope forms a series of Cenozoic sedimentary basins,including Qiongdongnan basin,Pearl River Mouth basin,Taixinan basin.These basins fill in thick Cenozoic fluviolacustrine facies,transitional facies,marine facies,abyssal facies sediment,recording the evolution history of South China Sea Margin rifting and ocean basin extending.The studies of tectonics and deposition of depression in the Southern Chaonan Sag of lower continental slope in the Norther South China Sea were dealt with,based on the sequence stratigraphy and depositional facies interpretation of seismic profiles acquired by cruises of“China and Germany Joint Study on Marine Geosciences in the South China Sea”and“The formation,evolution and key issues of important resources in China marginal sea",and combining with ODP 1148 cole and LW33-1-1 well.The free-air gravity anomaly of the break up of the continental and ocean appears comparatively low negative anomaly traps which extended in EW,it is the reflection of passive margin gravitational effect.Bouguer gravity anomaly is comparatively low which is gradient zone extended NE-SW.Magnetic anomaly lies in Magnetic Quiet Zone at the Northern Continental Margin of the South China Sea.The Cenozoic sediments of lower continental slope in Southern Chaonan Sag can be divided into five stratum interface:SB5.5,SB10.5,SB16.5,SB23.8 and Hg,their ages are of Pliocene-Quaternary,late Miocene,middle Miocene,early Miocene,paleogene.The tectonic evolution of low continental slope depressions can be divided into rifting,rifting-depression transitional and depression stages,while their depositional environments change from river to shallow marine and abyssa1,which results in different topography in different stages.The topographic evolvement in the study

  6. Five-year records of mercury wet deposition flux at GMOS sites in the Northern and Southern hemispheres

    Science.gov (United States)

    Sprovieri, Francesca; Pirrone, Nicola; Bencardino, Mariantonia; D'Amore, Francesco; Angot, Helene; Barbante, Carlo; Brunke, Ernst-Günther; Arcega-Cabrera, Flor; Cairns, Warren; Comero, Sara; Diéguez, María del Carmen; Dommergue, Aurélien; Ebinghaus, Ralf; Feng, Xin Bin; Fu, Xuewu; Garcia, Patricia Elizabeth; Gawlik, Bernd Manfred; Hageström, Ulla; Hansson, Katarina; Horvat, Milena; Kotnik, Jože; Labuschagne, Casper; Magand, Olivier; Martin, Lynwill; Mashyanov, Nikolay; Mkololo, Thumeka; Munthe, John; Obolkin, Vladimir; Ramirez Islas, Martha; Sena, Fabrizio; Somerset, Vernon; Spandow, Pia; Vardè, Massimiliano; Walters, Chavon; Wängberg, Ingvar; Weigelt, Andreas; Yang, Xu; Zhang, Hui

    2017-02-01

    The atmospheric deposition of mercury (Hg) occurs via several mechanisms, including dry and wet scavenging by precipitation events. In an effort to understand the atmospheric cycling and seasonal depositional characteristics of Hg, wet deposition samples were collected for approximately 5 years at 17 selected GMOS monitoring sites located in the Northern and Southern hemispheres in the framework of the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual and seasonal patterns in Hg wet deposition samples. Interannual differences in total wet deposition are mostly linked with precipitation volume, with the greatest deposition flux occurring in the wettest years. This data set provides a new insight into baseline concentrations of THg concentrations in precipitation worldwide, particularly in regions such as the Southern Hemisphere and tropical areas where wet deposition as well as atmospheric Hg species were not investigated before, opening the way for future and additional simultaneous measurements across the GMOS network as well as new findings in future modeling studies.

  7. Reconstructing depositional processes and history from reservoir stratigraphy: Englebright Lake, Yuba River, northern California

    Science.gov (United States)

    Snyder, N.P.; Wright, S.A.; Alpers, Charles N.; Flint, L.E.; Holmes, C.W.; Rubin, D.M.

    2006-01-01

    Reservoirs provide the opportunity to link watershed history with its stratigraphic record. We analyze sediment cores from a northern California reservoir in the context of hydrologic history, watershed management, and depositional processes. Observations of recent depositional patterns, sediment-transport calculations, and 137CS geochronology support a conceptual model in which the reservoir delta progrades during floods of short duration (days) and is modified during prolonged (weeks to months) drawdowns that rework topset beds and transport sand from topsets to foresets. Sediment coarser than 0.25-0.5 mm. deposits in foresets and topsets, and finer material falls out of suspension as bottomset beds. Simple hydraulic calculations indicate that fine sand (0.063-0.5 mm) is transported into the distal bottomset area only during floods. The overall stratigraphy suggests that two phases of delta building occurred in the reservoir. The first, from dam construction in 1940 to 1970, was heavily influenced by annual, prolonged >20 m drawdowns of the water level. The second, built on top of the first, reflects sedimentation from 1970 to 2002 when the influence of drawdowns was less. Sedimentation rates in the central part of the reservoir have declined ???25% since 1970, likely reflecting a combination of fewer large floods, changes in watershed management, and winnowing of stored hydraulic mining sediment. Copyright 2006 by the American Geophysical Union.

  8. Anastomosing river deposits: palaeoenvironmental control on coal quality and distribution, Northern Karoo Basin

    Energy Technology Data Exchange (ETDEWEB)

    Cairncross, B

    1980-01-01

    Borehole data from an area close to the northern margin of the Karoo Basin 110 m thick coal reveal a bearing succession of the Vryheid Formation overlying Dwyka tillite. The lowermost sediments reflect processes of deglaciation with a complex array of glaciolacustrine, glaciofluvial and alluvial-outwash fan deposits. Above this paraglacial milieu, tundra-type peat bogs developed in inactive areas and account for the two thick basal coal seams (No. 1 and 2 seams). During accumulation of peat which was later to form the extensive No. 2 coal seam, active clastic sedimentation was confined to laterally restricted river channels which incised into the underlying peat. Lateral migration was inhibited by vegetation stabilized river banks and channel deposits are characterized by vertically accreted upward-fining cycles. Channel fill consists of coarse-grinder bedload sediment deposited in anastomosing streams. Flood episodes are marked by widespread, but thin (< 1 m), shale zones that intercalate with the channel sandstones. Both sandstone and shale units are completely enveloped by No. 2 coal seams. This clastic parting influences No. 2 coal seam distribution and ash content. 23 references

  9. 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

    Directory of Open Access Journals (Sweden)

    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

  10. Age and paragenesis of mineralisation at Coronation Hill uranium deposit, Northern Territory, Australia

    Science.gov (United States)

    Orth, Karin; Meffre, Sebastien; Davidson, Garry

    2014-06-01

    Coronation Hill is a U + Au + platinum group elements deposit in the South Alligator Valley (SAV) field in northern Australia, south of the better known unconformity-style U East Alligator Rivers (EAR) field. The SAV field differs from the EAR by having a more complex basin-basement architecture. A volcanically active fault trough (Jawoyn Sub-basin) developed on older basement and then was disrupted by renewed faulting, before being buried beneath regional McArthur Basin sandstones that are also the main hanging wall to the EAR deposits. Primary mineralisation at Coronation Hill formed at 1607 ± 26 Ma (rather than 600-900 Ma as previously thought), and so it is likely that the SAV was part of a single west McArthur Basin dilational event. Most ore is hosted in sub-vertical faults and breccias in the competent volcanic cover sequence. This favoured fluid mixing, acid buffering (forming illite) and oxidation of Fe2+ and reduced C-rich assemblages as important uranium depositional mechanisms. However, reduction of U in fractured older pyrite (Pb model age of 1833 ± 67 Ma) is an important trap in diorite. Some primary ore was remobilised at 675 ± 21 Ma to form coarse uraninite + Ni-Co pyrite networks containing radiogenic Pb. Coronation Hill is polymetallic, and in this respect resembles the `egress'-style U deposits in the Athabascan Basin (Canada). However, these are all cover-hosted. A hypothesis for further testing is that Coronation Hill is also egress-style, with ores formed by fluids rising through basement-hosted fault networks (U reduction by diorite pyrite and carbonaceous shale), and into veins and breccias in the overlying Jawoyn Sub-basin volcano-sedimentary succession.

  11. Reconstructing the Holocene depositional environments along the northern coast of Sfax (Tunisia): Mineralogical and sedimentological approaches

    Science.gov (United States)

    Lamourou, Ali; Touir, Jamel; Fagel, Nathalie

    2017-05-01

    A sedimentological and mineralogical study of sedimentary cores allowed reconstructing the evolution of depositional environments along the Northern coast of Sfax (Tunisia). The aim of this research work is to identify the factors controlling the sedimentation from the Holocene to the Present time. Three 30-m sediment cores collected by drilling at 30 m water depth were analyzed for their color, magnetic susceptibility signal, grain size by laser diffraction, organic matter content by loss of ignition, carbonate content by calcimetry and mineralogy by X-ray diffraction on bulk powder and clay <2 μm. They broadly present the same sedimentological and mineralogical features. Microscopical observations of petrographic slides allowed identifying six main sedimentary facies. Bulk mineralogical assemblages comprised clay minerals, quartz, calcite, gypsum and K-feldspars were examined. Considerable change was observed in the carbonate content that mimicked the bioclaste abundance and diluted the detrital minerals (clay minerals, quartz and feldspars). The gypsum mainly occurred in the lower sedimentary columns (SC12 and SC9) and in the upper/middle of core SC6. The clay fraction was made of a mixture of kaolinite, illite, smectite and palygorskite with no clear variation through core depth. Both grain-size parameters and magnetic susceptibility profile showed a sharp transition in the upper 2-5 m of the sedimentological columns. Coarse, sandy to gravely sediments characterized by a low magnetic susceptibility signal were replaced by fine bioclastic-rich clayey sediments. The analysis of vertical succession of depositional facies revealed a fluvial depositional environment (coastal plain) basically marked by fluvial channels and inundation plains at the bottom of all cores. However, core-top sediments recorded a littoral marine environment with sand depositions rich in gastropods, lamellibranches and algæ. Depositional facies, sedimentological and mineralogical

  12. Volcaniclastic and sedimentary deposits in Late Oligocene/Early Miocene Smrekovec Volcanic Complex, northern Slovenia

    Science.gov (United States)

    Kralj, Polona

    2010-05-01

    Late Oligocene/Early Miocene volcanic activity in northern Slovenia is related to post-collisional accommodation of continental Apulian and oceanic European plates (von Blanckenburg and Davis, 1996). It occurred in one of small south-western marginal depressions of the Pannonian basin system, locally termed the Smrekovec Basin (Hanfland et al., 2004). Contemporaneous clastic sedimentation is evidenced by several hundred metres thick succession composed mainly of mudstone, siltstone and sand. Smrekovec Volcanic Complex (SVC) is an eroded and tectonically uplifted remain of a larger submarine stratovolcano edifice, built of lavas, shallow or subsurface intrusive bodies, and pyroclastic, hyaloclastic, syn-eruptively resedimented volcaniclastic and reworked volcaniclastic-sedimentary deposits (Kralj, 1996). The development of lithofacies of syn-eruptively resedimented deposits is controlled by the proximity to the ancient volcano summit and the volcano sloping. Moreover, close to the rising volcano edifice, distinct shallow-water environments with siliciclastic sedimentation developed. Syn-eruptively resedimented deposits are the most widespread and are related to volcaniclastic debris flows and volcaniclastic tubidity flows. Volcaniclastic debris flow deposits are subdivided into lithofacies Bx - polymict volcaniclastic breccia, and Bt - volcaniclastic tuff-breccia. Bx occurs as tabular, up to some ten metres thick bodies with abundant up to 5 dm large angular lava clasts and angular or rounded clasts of fine-grained tuff, and tuffaceous matrix. Bt forms basal, massive layers in fining-upward sequences. The main constituent is tuffaceous matrix; up to 1.5 dm large clasts of lavas and tuffs are subordinate. In a distance up to 2 km from the former volcano summit (proximal area), Bt predominates in the sequence lithofacies composition (~75 %), and attains a thickness of up to 4 m. At a distance of 2-4 km (distal area), a maximum Bt thickness rarely exceeds 5 dm, an

  13. THE CONTROL OF COCAINE IN THE NORTHERN REGION OF TARAPACA, CHILE, AS A RESULT OF THE IMPLEMENTATION OF THE “PLAN FRONTERA NORTE” (NORTHERN BORDERS PLAN

    Directory of Open Access Journals (Sweden)

    Juan Pablo Vidal Andrade

    2017-12-01

    Full Text Available The Northern Borders Plan was created as a unilateral policy by the Chilean government to address the problems of drug trafficking and transnational organized crime. It is important to determine and analyze the results of this policy and the actual impact of the drug trafficking controlC thereafter this article aims to analyze and check the variation of results and policies on security and traffic control of cocaine hydrochloride, from “Plan Frontera Norte” in the northern region of Tarapaca, from the perspective of one of the active organizations responsible for combating against the multidimensional threat: the Chilean Policia de Investigaciones.(PDI. The methodology of the article is the analysis of the situation of that policy through the data comparison, given basically by the public accounts of civilian police and official documents, which allow a deeper and serious analysis.

  14. Biomarkers and taphonomic processes in fresh and fossil biosignatures from Hot Spring silica deposits in El Tatio Chile, as a Mars Analogue

    Science.gov (United States)

    Carrizo, D.; Sánchez-García, L.; Parro, V.; Cady, S. L.; Cabrol, N. A.

    2017-09-01

    Biomarkers characterization and taphonomic process of recent and fossil biosignatures in extreme environments with analogies to Mars is essential to understanding how life could develop and survive in this conditions. Siliceous sinter deposits on Mars where similar to those found in the hydrothermal hot springs and geysers from El Tatio, Chile. Organic preservation have been shown in this study. Many different labile functional groups (i.e., carboxylic acids, alcohols, aldehydes, etc.) were found in both "age" samples. A shift in congener pattern for the different lipids families were found and discuss. This results give insight in taphonomic processes actin in this extreme environment, which could be used as a baseline in Mars exploration.

  15. Performance model to assist solar thermal power plant siting in northern Chile based on backup fuel consumption

    Energy Technology Data Exchange (ETDEWEB)

    Larrain, Teresita; Escobar, Rodrigo; Vergara, Julio [Departamento de Ingenieria Mecanica y Metalurgica, Pontificia Universidad Catolica de Chile, Vicuna Mackenna 4860, Macul, Santiago (Chile)

    2010-08-15

    In response to environmental awareness, Chile introduced sustainability goals in its electricity law. Power producers must deliver 5% from renewable sources by 2010 and 10% by 2024. The Chilean desert has a large available surface with one of the highest radiation levels and clearest skies in the World. These factors imply that solar power is an option for this task. However, a commercial plant requires a fossil fuel system to backup the sunlight intermittency. The authors developed a thermodynamical model to estimate the backup fraction needed in a 100 MW hybrid -solar-fossil- parabolic trough power plant. This paper presents the model aiming to predicting the performance and exploring its usefulness in assisting site selection among four locations. Since solar radiation data are only available in a monthly average, we introduced two approaches to feed the model. One data set provided an average month with identical days throughout and the other one considered an artificial month of different daylight profiles on an hourly basis for the same monthly average. We recommend a best plant location based on minimum fossil fuel backup, contributing to optimal siting from the energy perspective. Utilities will refine their policy goals more closely when a precise solar energy data set becomes available. (author)

  16. 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.

  17. 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

    Directory of Open Access Journals (Sweden)

    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.

  18. 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.

  19. 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.

  20. Transport of acid forming emissions and potential effects of deposition in northeastern Alberta and northern Saskatchewan: a problem analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shewchuk, S.R.; Abouguendia, Z.M.; Atton, F.M.; Dublin, J.; Godwin, R.C.; Holowaychuk, N.; Hopkinson, R.; Liaw, W.K.; Maybank, J.; Padbury, G.A.

    1981-01-01

    The purpose of this report is to study the potential effects of acid rain in northeastern Alberta and northern Saskatchewan. A problem analysis was conducted of the transport, transformations and deposition of emissions in this region. Studied are the atmospheric processes, geology and soils, natural vegetation, and the aquatic systems. At present, no environmental damage attributable to acidic deposition has been detected in this region. Field surveys in the region have detected no effects of industrial emissions on vegetation except within a few kilometers of industrial operations. The earliest effects of acid deposition tend to appear within aquatic systems. Ten recommendations based on these findings are discussed. 109 references, 22 figures, 10 tables.

  1. Variación ambiental y patrones di etarios del erizo negro Tetrapygus niger en costas intermareales rocosas del norte de Chile Environmental variation and dietary patterns of the black urchin Tetrapygus niger in rocky intertidal shores of northern Chile

    Directory of Open Access Journals (Sweden)

    ARTURO H NAVARRETE

    2008-09-01

    temperatura superficial del mar, y fue significativamente menor en todo el período de El Niño 2004-2005. Nuestros datos sugieren que T. niger es un generalista polífago cuyos patrones de consumo son fuertemente modulados por la fluctuación t��rmica ambiental. Además, hipotetizamos que T. niger puede usar estrategias oportunistas y selectivas sobre distintos recursos, y que su conectividad y posición trófica serían más complejas que las de un simple consumidor primario.The role and impact of herbivores on rocky intertidal food webs could be more complex and diverse than previously considered, particularly in the case of larger and more abundant consumers such as the black urchin Tetrapygus niger (Molina in the coast of Chile. In this context, we analyzed the variation in diet richness and composition of the black urchin in four rocky intertidal communities over a 1,000 km stretch of coast in northern Chile, sampled seasonally between the austral winter of 2004 and spring of 2005. The 2004-2005 El Niño event took place during the study, and we incorporated its potential effects to this evaluation. For each community and season, we measured the abundance of species present in 45 quadrants (0.25 m² distributed between five permanent blocks, collecting about 10 individuals of T. niger to measure their body size (dry biomass and maximum diameter and to determine the number, identity and occurrence frequency of dietary items in their gastric tract. We collected a total of 251 urchin individuals, which consumed 89 items of algae (64 % and invertebrates (36 %; including other herbivores. A significant inverse relationship between the number of ingested animal items and body size suggests that T. niger changes its diet throughout the ontogeny. Dietary niche breadth was high but tended to decrease toward lower latitudes. The spectrum and occurrence frequency of dietary items were not significantly different among communities, despite their marked differences in upwelling

  2. Effects of the 1982-1983 El Niño on the marine phytoplankton off northern Chile

    Science.gov (United States)

    Avaria, Sergio; MuñOz, Pablo

    1987-12-01

    The evolution of phytoplankton was studied between December 1980 and August 1985. A total of 1269 net and water samples were obtained in 11 cruises as part of the Estudio Regional del Fenómeno El Niño-Chile Program covering the area extending from Arica (18°30'S) to Chañaral (26°20'S) from the coast to 200 n. mi (370 km) westward. In the period which preceded the 1982-1983 El Niño event, the coastal phytoplankton consisted predominantly of blooming diatom species which support a large phytoplanktonic biomass. The cell density up to 20 n. mi (37 km) off the coast was over 100 cells mL-1, with a maximum density nucleus near the coast, where values over 1000 cells mL-1 were found. With the anomalous conditions produced by El Niño in December 1982, changes were detected in the phytoplankton biomass and composition. There was a marked decrease in the biomass, the diatom dominance was restricted to a narrow coast band of 2 to 3 n. mi (3.7-5.5 km), and warm water species of diatoms and dinoflagellates reached the coast. These conditions reached their maximum intensity in May 1983. Phytoplankton started to return to normal conditions in December 1983 with a predominance of large diatoms, which support a biomass somewhat larger than that during El Niño. Small diatoms returned as the dominant species in large blooms in 1985. The cell numbers reached values similar to those during pre-Niño conditions, with a normal neritic and oceanic phytoplankton distribution. Red tides caused by the ciliate Mesodinium rubrum were common during normal conditions before and after El Niño.

  3. Insights into Andean slope hydrology: reservoir characteristics of the thermal Pica spring system, Pampa del Tamarugal, northern Chile

    Science.gov (United States)

    Scheihing, Konstantin W.; Moya, Claudio E.; Tröger, Uwe

    2017-09-01

    The thermal Pica springs, at ˜1,400 m above sea level (asl) in the Pampa del Tamarugal (Chile), represent a low-saline spring system at the eastern margin of the hyper-arid Atacama Desert, where groundwater resources are scarce. This study investigates the hydrogeological and geothermal characteristics of their feed reservoir, fostered by the interpretation of a 20-km east-west-heading reflection-seismic line in the transition zone from the Andean Precordillera to the Pampa del Tamarugal. Additional hydrochemical, isotope and hydrologic time-series data support the integrated analysis. One of the main factors that enabled the development of the spring-related vertical fracture system at Pica, is a disruption zone in the Mesozoic Basement caused by intrusive formations. This destabilized the younger Oligocene units under the given tectonic stress conditions; thus, the respective groundwater reservoir is made up of fractured Oligocene units of low to moderate permeability. Groundwater recharge takes place in the Precordillera at ˜3,800 m asl. From there groundwater flow covers a height difference of ˜3,000 m with a maximum circulation depth of ˜800-950 m, where the waters obtain their geothermal imprint. The maximal expected reservoir temperature, as confirmed by geothermometers, is ˜55 °C. Corrected mean residence times of spring water and groundwater plot at 1,200-4,300 years BP and yield average interstitial velocities of 6.5-22 m/year. At the same time, the hydraulic head signal, as induced by recharge events in the Precordillera, is transmitted within 20-24 months over a distance of ˜32 km towards the Andean foothills at Pica and Puquio Nunez.

  4. Marine resource reliance in the human populations of the Atacama Desert, northern Chile - A view from prehistory

    Science.gov (United States)

    King, Charlotte L.; Millard, Andrew R.; Gröcke, Darren R.; Standen, Vivien G.; Arriaza, Bernardo T.; Halcrow, Siân E.

    2018-02-01

    The Atacama Desert is one of the most inhospitable terrestrial environments on Earth, yet the upwelling of the Humboldt Current off the coast has resulted in the presence of a rich marine biota. It is this marine environment which first enabled the human settlement of the northern Atacama Desert, and continues to form the basis of regional economies today. In this paper we explore how the desert has shaped human dietary choices throughout prehistory, using carbon and nitrogen isotope analysis of human bone collagen (n = 80) to reconstruct the diets of the inhabitants of the Arica region of the northern Atacama. This area is one of the driest parts of the desert, but has been generally understudied in terms of dietary adaptation. Statistical analysis using FRUITS has allowed deconvolution of isotopic signals to create dietary reconstructions and highlight the continued importance of marine resources throughout the archaeological sequence. Location also appears to have played a role in dietary choices, with inland sites having 10-20% less calories from marine foods than coastal sites. We also highlight evidence for the increasing importance of maize consumption, coinciding with contact with highland polities. In all periods apart from the earliest Archaic, however, there is significant variability between individuals in terms of dietary resource use. We conclude that marine resource use, and broad-spectrum economies persisted throughout prehistory. We interpret these results as reflecting a deliberate choice to retain dietary diversity as a buffer against resource instability.

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

    Science.gov (United States)

    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

  6. New data on OSL dating of Early Khalynian deposits of Northern Caspian

    Science.gov (United States)

    Sychev, Nikita; Yanina, Tamara; Svitoch, Alexander; Kurbanov, Redzhep; Badyukova, Ekaterina

    2016-04-01

    Ponto-Caspian region is the key region the study of which can provide information about the paleogeographic history of the central Eurasia, particularly revealing the history of the East European Plain, the Caucasus and Central Asia. However, despite the long history of the study, today there is no accepted general stratigraphic scheme of the Caspian Sea. One of the most interesting and important stages of Late Pleistocene history of Caspian is Khalynian transgression which is divided into two major phases: early and ate. In the Caspian lowland Lower Khalynian stage are represented by a unique type of deposit - "chocolate clays". A distinctive feature of these sediments is widely distributed among Lower Khalynian deposits of Northern Caspian and the Volga region. All clay deposits are confined to the diverse origins of depression before-Khalynian relief. Chocolate clays formation consists of facies: mono-clay (typological), layered, sand- and silty-clay (Svitoch, Yanina, 1997). Determining the age of chocolate clays by optically stimulated luminescence (OSL) in our view will allow bettering the understanding of their genesis. Age of chocolate clays of Lower Volga was widely dated using the radiocarbon. However, the existing chronology is controversial, raises a number of issues, primarily due to the material of which are used for dating - thin shells of Caspian mollusks of the Didacna Eichw. genus, which are characterized by a significant isotopic exchange with the enclosing sediments (Arslanov, 2015). Lower Volga region is characterized by very complex geological structure of the Late Pleistocene deposits (alternating continental aeolian, alluvial and slope sediments with marine Caspian deposits of different age). There are many conflicting opinions, not only with respect to paleogeographic features of the area, but also to its precise chronology. The differences in opinion over the age of the individual stages of development of the Caspian Sea (transgressions and

  7. Trends of deposition fluxes and loadings of sulfur dioxide and nitrogen oxides in the artificial Three Northern Regions Shelter Forest across northern China

    International Nuclear Information System (INIS)

    Zhang, Xiaodong; Huang, Tao; Zhang, Leiming; Gao, Hong; Shen, Yanjie; Ma, Jianmin

    2015-01-01

    This study provides the first estimate of dry deposition fluxes of criteria air pollutants (SO_2 and NO_x) across the Three Northern Regions Shelter Forest (TNRSF) region in Northern China and their long-term trends from 1982 to 2010 using the inferential method. Dry deposition velocities of SO_2 and NO_x increased in many places of the TNRSF up to 118.2% for SO_2 and 112.1% for NO_x over the last three decades due to the increased vegetation coverage over the TNRSF. The highest atmospheric deposition fluxes of SO_2 and NO_x were found in the Central-North China region, followed by the Northeast and the Northwest China regions of the TNRSF. A total of 820,000 t SO_2 and 218,000 t NO_x was estimated to be removed from the atmosphere through dry deposition process over the TNRSF from 1982 to 2010. About 50% of the total removal occurred in the Central-North China region. The estimated total SO_2 and NO_x dry deposition fluxes from 1982 to 2010 between a TNRSF site in this region and an adjacent farmland outside the TNRSF showed that the fluxes of these two chemicals at the TNRSF site were the factors of 2–3 greater than their fluxes in the farmland. - Highlights: • We investigate removal of air pollutants by the Three-North Shelter Forest (Green Great Wall) in China. • The trend of SO_2 and NO_x dry deposition velocity and flux over the TNRSF increase over the last three decades. • Increasing trends of deposition fluxes of SO_2 and NO_x are more evident in Central-North and Northeast China. • We show higher deposition fluxes of SO_2 and NO_x within the TNSF than outside TNRSF. • Stronger removal of air pollutants by the TNRSF is expected when other criteria air pollutants are taken into account. - The TNRSF is demonstrated to be an effective sink for SO_2 and NO_x and has increased the removal of air pollutants from Northern China.

  8. Evaluación del crecimiento del pulpo común Octopus mimus del norte de Chile alimentado con dietas formuladas Growth evaluation of octopus (Octopus mimus from northern Chile fed with formulated diets

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    Oscar Zúñiga

    2011-11-01

    Full Text Available Durante 57 días se comparó el crecimiento y sobreviviencia de pulpos juveniles Octopus mimus del norte de Chile alimentados con tres diferentes dietas: dos dietas húmedas (A y B aglutinadas con solución de gelatina embutidas en tripa de cordero y una dieta control (C natural. La dieta (A fue elaborada en base a una mezcla de filete triturado del pescado Cheilodactylus variegatus con harina de pellet para salmón, la dieta (B con pasta de almeja (Protothaca thaca mezclada con filete de Ch. variegatus y la dieta control consistió en el suministro de almejas frescas congeladas (C. Basado en un diseño experimental de medidas repetidas, los pulpos se mantuvieron individualmente en estanques de 70 L con circulación de agua de mar y aireación permanente. Los pulpos que consumieron la dieta B no experimentaron mortalidad y la dieta control C presentó mortalidad del 16,7%, sus crecimiento fueron similares (P > 0,05 con tasas de crecimiento absoluta (AGR de 7,0 ± 0,91 (g d-1 y 6,6 ± 1,10 (g d-1 respectivamente. Los pulpos alimentados con la dieta A registraron mortalidad de 33,3% y tasa de crecimiento absoluta negativa, AGR= -1,70 ± 0,37 (g d-1. La dieta A que contenía como ingrediente pellet para salmón molido como harina no tuvo una adecuada aceptación y los ejemplares experimentaron disminución de su peso. La dieta B preparada con gelatina de origen animal como aglutinante, no implicó un efecto negativo en la palatabilidad y aceptabilidad en comparación al control basada en almeja fresca congelada, incluso los organismos lograron crecimientos similares. Los resultados permitirán a futuro mejorar la calidad nutricional de dietas artificiales para maximizar el crecimiento de O. mimus en cautiverio.The growth and survival of juvenile octopus, Octopus mimus, from northern Chile, fed three different diets were analyze during 57 days. Two of the diets (A and B were wet diets stuffed in lamb gut with a gelatin solution, and the third (C was

  9. Reconstruction of the palaeoenvironment using biomarkers and clay mineralogy in loess deposits of northern Iran

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    A. Shahriari

    2016-10-01

    Full Text Available Introduction: Knowledge about palaeoenviroment and palaeovegetation provides information about how vegetation reacts on climate fluctuations in the past, what will help understanding current and future developments caused by e.g. climate change. Northern Iranian Loess-Plateau forms a strongly dissected landscape with steeply sloping loess hills. This loess record reflects numerous cycles of climate change and landscape evolution for the Middle to Late Quaternary period. therefore, this study was done for reconstruction of palaeoenvironment (climate and vegetation in loess-palaeosol sequences in northern Iran. Therefore, this study aims at a preliminary reconstruction of palaeovegetation and palaeoenvironment, in loess-palaeosol sequences along a cliomosequnce in Northern Iran. Materials and Methods: Two loess-palaeosol sequences (Agh Band and Nowdeh sections were chosen in Golestan province, in northern Iran and step-wise profiles were prepared. Agh Band section is located in the western most part of the Northern Iranian loess plateau and has about 50 m thickness of loess deposits. Nowdeh loess-palaeosol sequence is located about 20 km southeast of Gonbad-e Kavus, in the vicinity of the Nowdeh River. Soil sampling was done in several field campaigns in spring 2012. More than 30cm of the surface deposits were removed in order to reach for undisturbed loess and palaeosols and one mixed sample was taken from each horizonA comparison of palaeosols with modern soils formed under known Holocene climatic conditions, which are derived from substrates with similar granulometric and mineralogical composition are suited for reconstructing past climate and environment. Hence, six modern soil profiles were prepared along the climosequnce and the vegetation cover changed from grassland in the dry area to dense shrub land and forest in the moist part of the ecological gradient. For reconstruction of palaeoenvironment (climate and vegetation some basic physico

  10. Protecting Dark Skies in Chile

    Science.gov (United States)

    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.

  11. Metals in bulk deposition and surface waters at two upland locations in northern England

    Energy Technology Data Exchange (ETDEWEB)

    Lawlor, A.J.; Tipping, E

    2003-02-01

    Surface water concentrations of potentially-toxic metals depend upon atmospheric deposition and catchment biogeochemical processes. - Concentrations of aluminium and minor metals (Mn, Ni, Cu, Zn, Sr, Cd, Ba, Pb) were measured in precipitation and surface water at two upland locations (Upper Duddon Valley, UDV; Great Dun Fell, GDF) in northern England for 1 year commencing April 1998. At both locations, the loads in bulk precipitation were at the lower ends of ranges reported for other rural and remote sites, for the period 1985-1995. The deposited metals were mostly in the dissolved form, and their concentrations tended to be greatest when rainfall volumes were low. The concentrations of Cu, Zn and Pb in deposition were correlated (r{sup 2}{>=}0.40) with concentrations of non-marine sulphate. Three streams, ranging in mean pH from 5.07 to 7.07, and with mean concentrations of dissolved organic carbon (DOC) <1 mg l{sup -1}, were monitored at UDV, and two pools (mean pH 4.89 and 6.83, mean DOC 22 and 15 mg l{sup -1}) at GDF. Aluminium and the minor metals were mainly in the dissolved form, and in the following ranges (means of 49-51 samples, {mu}g l{sup -1}): Al 36-530, Mn 4.4-36, Ni 0.26-2.8, Cu 0.25-1.7, Zn 2.1-30, Cd 0.03-0.16, Ba 1.9-140, Pb 0.10-4.5. Concentrations were generally higher at GDF. Differences in metal concentrations between the two locations and between waters at each location, and temporal variations in individual waters, can be explained qualitatively in terms of sorption to solid-phase soil organic matter and mineral surfaces, complexation and transport by DOC, and chemical weathering. The UDV catchments are sinks for Pb and sources of Al, Mn, Sr, Cd and Ba. The GDF catchments are sources of Al, Mn, Ni, Zn, Sr, Cd and Ba. Other metals measured at the two locations are approximately in balance. Comparison of metal:silicon ratios in the surface waters with values for silicate rocks indicates enrichment of Ni and Cu, and substantial enrichment of

  12. Carbonate cementation in the late glacial outwash and beach deposits in northern Estonia

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    Maris Rattas

    2014-02-01

    Full Text Available The sedimentary environments, morphology and formation of carbonate cement in the late glacial glaciofluvial outwash and beach deposits in northern Estonia are discussed. Cementation is observed in well-drained, highly porous carbonaceous debris-rich gravel and sand-forming, resistant ledges in otherwise unconsolidated sediments. The cemented units occur as laterally continuous layers or as isolated lenticular patches with thicknesses from a few centimetres to 3 m. The cement is found in two main morphologies: (1 cement crusts or coatings around detrital grains and (2 massive cement almost entirely filling interparticle pores and intraparticle voids. It is exclusively composed of low-Mg calcite with angular equant to slightly elongated rhombohedral and scalenohedral or prismatic crystals, which indicate precipitation from meteoric or connate fresh surface (glacial lake water and/or near-surface groundwater under low to moderate supersaturation and flow conditions. The absence of organic structures within the cement suggests that cementation is essentially inorganic. The cement exhibits both meteoric vadose and phreatic features and most probably occurred close to the vadose–phreatic interface, where the conditions were transitional and/or fluctuating. Cementation has mainly taken place by CO2-degassing in response to fluctuations in groundwater level and flow conditions, controlled by the Baltic Ice Lake water level, and seasonal cold and/or dry climate conditions.

  13. Restoration of degraded drylands in northern Chile: The need of local stakeholders' participation to prevent and combat desertification

    Science.gov (United States)

    Jorquera-Jaramillo, Carmen; Yáñez-Acevedo, Marcia; Gutiérrez, Julio R.; Cortés-Bugueño, José Luis; Pastén-Marambio, Víctor; Barraza-Cepeda, Claudia

    2015-04-01

    Desertification is one of the main factors determining poverty, long-term socio-economic problems, natural resources depletion and disturbances in rural communities living at the Coquimbo Region drylands (North-Central Chile). The Chilean State, along with private initiatives, have invested 473.6 Million dollars (1976 to 2008) to recover degraded areas through afforestation and soil management of 1,373,758 hectares. However, there is no information about the impact of the practices and changes experienced by the local stakeholders. Therefore, there is a need for a comprehensive evaluation considering both socioeconomic and biophysical aspects. To this end, a Protocol on Integrated Assessment (IAPro, PRACTICE project) was applied in two rural communities, involving communal afforested sites and their adjacent degraded drylands: El Sauce (ES, Limarí province) and Las Cañas (LC, Choapa province), Coquimbo Region. Participatory afforestation and soil conservation projects were implemented at both sites by the Chilean National Forestry Service (CONAF) in agreement with each local community (Jiménez y Tapia Agricultural Community at ES and Las Cañas de Choapa Peasant's Community at LC). The protocol involved 7 steps: (1) Stakeholder platform identification and engagement; (2) Baseline assessment and selection of site-specific indicators; (3) Integration and weighting of common and site-specific indicators; (4) Data collection; (5) Integrating and perspectives on a MCDA (Multi-Criteria Decision Analysis); (6) Collective Integrated assessment and knowledge sharing; (7) Dissemination. Interviews involved local and institutional stakeholders related to both sites' implementation, administration and/or local impacts. For the ES site, 5 actions were defined and assessed: No action (control); fences; mechanic and biological practices (soil stabilization, runoff control on slopes); runoff control in micro-basins, gullies and ravines; and footpath for educational and

  14. The Amazon-Laurentian connection as viewed from the Middle Proterozoic rocks in the central Andes, western Bolivia and northern Chile

    Science.gov (United States)

    Tosdal, R.M.

    1996-01-01

    Middle Proterozoic rocks underlying the Andes in western Bolivia, western Argentina, and northern Chile and Early Proterozoic rocks of the Arequipa massif in southern Peru?? from the Arequipa-Antofalla craton. These rocks are discontinuously exposed beneath Mesozoic and Cenozoic rocks, but abundant crystalline clasts in Tertiary sedimentary rocks in the western altiplano allow indirect samples of the craton. Near Berenguela, western Bolivia, the Oligocene and Miocene Mauri Formation contains boulders of granodiorite augen gneiss (1171??20 Ma and 1158??12 Ma; U-Pb zircon), quartzose gneiss and granofels that are inferred to have arkosic protoliths (1100 Ma source region; U-Pb zircon), quartzofeldspathic and mafic orthogneisses that have amphibolite- and granulite-facies metamorphic mineral assemblages (???1080 Ma metamorphism; U-Pb zircon), and undeformed granitic rocks of Phanerozoic(?) age. The Middle Proterozoic crystalline rocks from Berenguela and elsewhere in western Bolivia and from the Middle Proterozoic Bele??n Schist in northern Chile generally have present-day low 206Pb/204Pb ( 15.57), and elevated 208Pb/204Pb (37.2 to 50.7) indicative of high time-averaged Th/U values. The Middle Proterozoic rocks in general have higher presentday 206Pb/204Pb values than those of the Early Proterozoic rocks of the Arequipa massif (206Pb/204Pb between 16.1 and 17.1) but lower than rocks of the southern Arequipa-Antofalla craton (206Pb/204Pb> 18.5), a difference inferred to reflect Grenvillian granulite metamorphism. The Pb isotopic compositions for the various Proterozoic rocks lie on common Pb isotopic growth curves, implying that Pb incorporated in rocks composing the Arequipa-Antofalla craton was extracted from a similar evolving Pb isotopic reservoir. Evidently, the craton has been a coherent terrane since the Middle Proterozoic. Moreover, the Pb isotopic compositions for the Arequipa-Antofalla craton overlap those of the Amazon craton, thereby supporting a link

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

    Directory of Open Access Journals (Sweden)

    Hans Niemeyer

    2009-01-01

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

  16. 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.

  17. Calibrating coseismic coastal land-level changes during the 2014 Iquique (Mw=8.2) earthquake (northern Chile) with leveling, GPS and intertidal biota.

    Science.gov (United States)

    Jaramillo, Eduardo; Melnick, Daniel; Baez, Juan Carlos; Montecino, Henry; Lagos, Nelson A; Acuña, Emilio; Manzano, Mario; Camus, Patricio A

    2017-01-01

    The April 1st 2014 Iquique earthquake (MW 8.1) occurred along the northern Chile margin where the Nazca plate is subducted below the South American continent. The last great megathrust earthquake here, in 1877 of Mw ~8.8 opened a seismic gap, which was only partly closed by the 2014 earthquake. Prior to the earthquake in 2013, and shortly after it we compared data from leveled benchmarks, deployed campaign GPS instruments, continuous GPS stations and estimated sea levels using the upper vertical level of rocky shore benthic organisms including algae, barnacles, and mussels. Land-level changes estimated from mean elevations of benchmarks indicate subsidence along a ~100-km stretch of coast, ranging from 3 to 9 cm at Corazones (18°30'S) to between 30 and 50 cm at Pisagua (19°30'S). About 15 cm of uplift was measured along the southern part of the rupture at Chanabaya (20°50'S). Land-level changes obtained from benchmarks and campaign GPS were similar at most sites (mean difference 3.7±3.2 cm). Higher differences however, were found between benchmarks and continuous GPS (mean difference 8.5±3.6 cm), possibly because sites were not collocated and separated by several kilometers. Subsidence estimated from the upper limits of intertidal fauna at Pisagua ranged between 40 to 60 cm, in general agreement with benchmarks and GPS. At Chanavaya, the magnitude and sense of displacement of the upper marine limit was variable across species, possibly due to species-dependent differences in ecology. Among the studied species, measurements on lithothamnioid calcareous algae most closely matched those made with benchmarks and GPS. When properly calibrated, rocky shore benthic species may be used to accurately measure land-level changes along coasts affected by subduction earthquakes. Our calibration of those methods will improve their accuracy when applied to coasts lacking pre-earthquake data and in estimating deformation during pre-instrumental earthquakes.

  18. 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.

  19. Egg production and hatching success of Calanus chilensis and Acartia tonsa in the northern Chile upwelling zone (23°S), Humboldt Current System

    Science.gov (United States)

    Ruz, Paula M.; Hidalgo, Pamela; Yáñez, Sonia; Escribano, Rubén; Keister, Julie E.

    2015-08-01

    Oxygen Minimum Zones (OMZ's) are expanding and intensifying as result of climate change, affecting Eastern Boundary Upwelling Systems. Local effects of vertical movements of OMZ's that result from changes in upwelling intensity could reduce or expand the oxygenated surface layer that most zooplanktonic species inhabit in coastal areas. Using the copepods Calanus chilensis and Acartia tonsa as model organisms, an experimental test of the impact of different dissolved oxygen (DO) concentrations (between 0.5 and 5 ml L- 1) on egg production and hatching success was carried out and compared with field estimations of egg production, female and egg abundance in Mejillones Bay (23°S). Abundance of C. chilensis was highly variability and no consistent pattern in egg production and hatching success was found across DO levels, whereas A. tonsa egg production had maximum values between 2.6 and 4.7 ml O2 L- 1 and hatching success was positively correlated with DO (r = 0.75). In the field, temperature was the main factor controlling the dynamics of both species, while Chl-a and DO were also correlated with C. chilensis and A. tonsa, respectively. Principal Component Analysis showed that abundances of both copepods were controlled by temperature, stratification, OMZ depth, and Ekman transport, which together explained more than 70% of the total variance and were the main factors that modulated the populations of C. chilensis and A. tonsa in the upwelling zone of northern Chile (23°S). The differential responses of C. chilensis and A. tonsa to changes in DO concentrations associated with vertical movements of the OMZ suggest that C. chilensis may be better adapted to hypoxic conditions than A. tonsa, however both species are successful and persistent all year-round. We suggest that physiological responses of copepods could be used to evaluate population dynamics affected by the shoaling of OMZ's and the repercussions to trophic food webs of eastern boundary current systems.

  20. Estuary deposits in the Río Baguales Formation (Chattian-Aquitanean, Magallanes Province, Chile Depósitos estuarinos en la Formación Río Baguales (Chattiano-Aquitaniano, Provincia de Magallanes, Chile

    Directory of Open Access Journals (Sweden)

    Jacobus P Le Roux

    2010-07-01

    Full Text Available Very little work has been done on the stratigraphy and sedimentology of the upper Oligocene-Lower Miocene Río Baguales Formation in the Magallanes Province of southern Chile since its original definition in 1957. A detailed stratigraphic section of the upper part of the formation exposed west of the Baguales River is presented, with an interpretation of depositional environments. This indicates a prograding shoreline in which estuary mouth, middle estuary (lagoon and bay head delta facies are represented. Large-scale delta slope foresets indicate progradation towards the north and northwest, whereas southeast-directed cross-beds on the delta front probably suggest wave action. The general sequence reflects a gradual sea-level fall largely counteracted by tectonic subsidence, which provided the ne-cessary accommodation space for thick tidal flat and subtidal deposits to accumulate. A longer period of transgression towards the top of the succession may be related to a rise in sea-level or accelerated tectonic subsidence, whereas a major regression commencing at around 23.3 Ma probably coincides with the opening of the Drake Passage and the growth of the East Antarctic Ice Sheet.Hay muy pocos trabajos sobre la estratigrafía y sedimentología de la Formación Río Baguales del Oligoceno superior-Mioceno inferior en la Provincia de Magallanes del sur de Chile, luego de su primera definición en 1957. Se presenta un perfil estratigráfico detallado de la parte superior de la formación al oeste del río Baguales, con una interpretación de los ambientes de depositación. Se identificó una costa progradante con facies de boca de estuario, medio de estuario (laguna y delta de cabecera. Las grandes capas frontales del talud deltaico indican progradación hacia el norte y noroeste, mientras que la presencia de laminación cruzada inclinada hacia el sureste sugiere la acción de oleaje. La sucesión en general refleja una caída gradual del nivel del

  1. Exploring the diversity and antimicrobial potential of marine Actinobacteria from the Comau Fjord in Northern Patagonia, Chile

    Directory of Open Access Journals (Sweden)

    Agustina Undabarrena

    2016-07-01

    Full Text Available Bioprospecting natural products in marine bacteria from fjord environments are attractive due to their unique geographical features. Although Actinobacteria are well known for producing a myriad of bioactive compounds, investigations regarding fjord-derived marine Actinobacteria are scarce. In this study, the diversity and biotechnological potential of Actinobacteria isolated from marine sediments within the Comau fjord, in Northern Chilean Patagonia, were assessed by culture-based approaches. The 16S rRNA gene sequences revealed that members phylogenetically related to the Micrococcaceae, Dermabacteraceae, Brevibacteriaceae, Corynebacteriaceae, Microbacteriaceae, Dietziaceae, Nocardiaceae and Streptomycetaceae families were present at the Comau fjord. A high diversity of cultivable Actinobacteria (10 genera was retrieved by using only five different isolation media. Four isolates belonging to Arthrobacter, Brevibacterium, Corynebacterium and Kocuria genera showed 16S rRNA gene identity <98.7% suggesting that they are novel species. Physiological features such as salt tolerance, artificial sea water requirement, growth temperature, pigmentation and antimicrobial activity were evaluated. Arthrobacter, Brachybacterium, Curtobacterium, Rhodococcus and Streptomyces isolates showed strong inhibition against both Gram-negative Pseudomonas aeruginosa, Escherichia coli and Salmonella enterica and Gram-positive Staphylococcus aureus, Listeria monocytogenes. Antimicrobial activities in Brachybacterium, Curtobacterium and Rhodococcus have been scarcely reported, suggesting that non-mycelial strains are a suitable source of bioactive compounds. In addition, all strains bear at least one of the biosynthetic genes coding for NRPS (91%, PKS I (18% and PKS II (73%.Our results indicate that the Comau fjord is a promising source of novel Actinobacteria with biotechnological potential for producing biologically active compounds.

  2. TRANSITION FROM CARBONATE PLATFORM TO PELAGIC DEPOSITION (MID JURASSIC- LATE CRETACEOUS, VOURINOS MASSIF, NORTHERN GREECE

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    NICOLAOS CARRAS

    2004-03-01

    Full Text Available A Jurassic- Cretaceous carbonate succession crops out along the Zyghosti Rema, Kozani (Northern Greece. The substratum consists of the ophiolitic succession of the Vourinos Massif (Pelagonian Domain: serpentinites tectonically overlain by basalts, with thin lenses of radiolarian cherts of middle Bathonian age. The contact with the overlying Jurassic limestones is tectonic. Eight informal units have been distinguished within the Mesozoic limestones, from the base upwards. (A bioclastic, intraclastic and oolitic packstone (Callovian- Oxfordian. (B bioclastic packstone and coral boundstone (Oxfordian . (C bioclastic and oncoidal wackestone with Clypeina jurassica (Oxfordian- Upper Kimmeridgian. (D (Upper Kimmeridgian- Portlandian: oncoidal packstone and rudstone (facies D1; intraclastic and bioclastic grainstone and packstone (facies D2; neptunian dykes with intraclastic and bioclastic wackestone and packstone filling (facies D3; neptunian dykes with Fe-Mn rich laterite filling and with pink silty filling of early Late Cretaceous age. An unconformity surface, due to emersion and erosion of the platform during the latest Jurassic- Early Cretaceous, is overlain by (E intraclastic, bioclastic packstone and grainstone (Cenomanian. (F massive body of debrites with coral, echinoderm, algae and rudist large clasts (facies F1 (Cenomanian; turbiditic beds of bioclastic, intraclastic and lithoclastic rudstone and grainstone (facies F2. (G thin bedded bioclastic mudstone and wackestone with planktonic foraminifers and radiolarians, alternating with turbiditic beds of bioclastic, intraclastic packstone and rudstone and with conglomeratic levels and slumped beds of the previous turbidites (upper Santonian- lower Campanian. (H: bioclastic packstone with planktonic foraminifers (facies H1 (lower Campanian - ?Maastrichtian; amalgamated turbiditic beds of bioclastic wackestone and packstone with planktonic foraminifers (facies H2; turbiditic beds of bioclastic

  3. Litho- and chemostratigraphy of the Flatreef PGE deposit, northern Bushveld Complex

    Science.gov (United States)

    Grobler, D. F.; Brits, J. A. N.; Maier, W. D.; Crossingham, A.

    2018-05-01

    The Flatreef is a world-class platinum-group element (PGE) deposit recently discovered down-dip from existing mining and exploration operations on the northern limb of the Bushveld Complex. Current indicated resources stand at 42 Moz PGE (346 Mt with 3.8 g/t Pt+Pd+Rh+Au, 0.32% Ni and 0.16% Cu) which, in the case of Pt, is equivalent to 10 years global annual production, making it one of the largest PGE deposits on earth. The grade and thickness of the Flatreef mineralised interval is highly unusual, with some drill core intersections containing up to 4.5 g/t Pt+Pd+Rh+Au over 90 m in drill core. Here, we document the down-dip and along-strike litho- and chemostratigraphy of the Flatreef and its footwall and hanging wall rocks, based on a diamond drill core database totalling > 720 km. At the base of the sequence intersected in the drill cores are up to 700-m-thick sills of ultramafic rocks (dunite, harzburgite, pyroxenite) emplaced into pelitic, dolomitic, and locally quartzitic and evaporitic rocks belonging to the Duitschland Formation of the Transvaal Supergroup. Next is an approximately 100-200-m sequence of low-grade-sulphide-mineralised, layered mafic-ultramafic rocks containing abundant sedimentary xenoliths and, in places, several chromite seams or stringers. This is overlain by a 100-m-thick sequence of well-mineralised mafic-ultramafic rocks (the Flatreef sensu strictu), overlain by a laterally persistent mottled compositional analogies at the base of > 1 km of homogenous Main Zone gabbronorite. Based on stratigraphic, lithological and compositional alanalogies to the layered rocks in the eastern and western Bushveld Complex, we correlate the Flatreef and its chromite bearing footwall rocks with the Upper Critical Zone, notably the interval between the UG2 chromitite and the Bastard Reef as found elsewhere in the Bushveld Complex. This includes recognition of a Merensky Reef correlative. The ultramafic rocks below the main chromitite seam (UG2 correlative

  4. Geochemical Prospecting of a Uraniferous Bog Deposit at Masugnsbyn, Northern Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Armands, Goesta

    1961-01-15

    In connection with prospecting for uranium ores in northern Sweden a peat bog, situated 4.5 km NW of Masugnsbyn, Norrbotten, Sweden and showing a remarkable content of uranium, was discovered. Closer investigation of several samples of the peat indicated that the comparatively high content of uranium and radon was connected with the occurrence of radioactive springs in the region. It was found that four different kinds of water were responsible for the supply of radioactive material to the peat, viz: ground water, surface water, spring water and ground water emanating from fractured rock. The spring water - probably a mixture of ground water and water from the fractured rock - contains uranium to the extent of micrograms per litre. The pH is about 7. The uranium content of the water system deriving from the fractured rock is about 200-300 micrograms per litre. The maximum radon content is about 3000 emans. The pH is >7 and the specific conductivity about 150 x 10{sup -6}/Ohm/cm The radioactive peat is characterised by extremely low gamma radioactivity which may be due to the recent emplacement of uranium by spring waters. It is suggested that the peat in question has served as a 'collector' for uranium, rare earth metals etc., since the pH condition - pH about 7 - was favourable to the settling of these elements. The uranium enrichment seems to be due to a transport of Na, Mg and Ca bicarbonates emanating from dolomite deposits or pegmatitic granite dikes in the vicinity of the peat, the bicarbonate waters serving as carriers of the uranium.

  5. Geochemical Prospecting of a Uraniferous Bog Deposit at Masugnsbyn, Northern Sweden

    International Nuclear Information System (INIS)

    Armands, Goesta

    1961-01-01

    In connection with prospecting for uranium ores in northern Sweden a peat bog, situated 4.5 km NW of Masugnsbyn, Norrbotten, Sweden and showing a remarkable content of uranium, was discovered. Closer investigation of several samples of the peat indicated that the comparatively high content of uranium and radon was connected with the occurrence of radioactive springs in the region. It was found that four different kinds of water were responsible for the supply of radioactive material to the peat, viz: ground water, surface water, spring water and ground water emanating from fractured rock. The spring water - probably a mixture of ground water and water from the fractured rock - contains uranium to the extent of micrograms per litre. The pH is about 7. The uranium content of the water system deriving from the fractured rock is about 200-300 micrograms per litre. The maximum radon content is about 3000 emans. The pH is >7 and the specific conductivity about 150 x 10 -6 /Ohm/cm The radioactive peat is characterised by extremely low gamma radioactivity which may be due to the recent emplacement of uranium by spring waters. It is suggested that the peat in question has served as a 'collector' for uranium, rare earth metals etc., since the pH condition - pH about 7 - was favourable to the settling of these elements. The uranium enrichment seems to be due to a transport of Na, Mg and Ca bicarbonates emanating from dolomite deposits or pegmatitic granite dikes in the vicinity of the peat, the bicarbonate waters serving as carriers of the uranium

  6. Environmental studies in two communes of Santiago de Chile by the analysis of magnetic properties of particulate matter deposited on leaves of roadside trees

    Science.gov (United States)

    Muñoz, David; Aguilar, Bertha; Fuentealba, Raúl; Préndez, Margarita

    2017-03-01

    Emissions from motor vehicles are considered to be one of the main sources of airborne particulate matter in Santiago. International researchers have shown that particulate matter contains metal oxides and magnetic particles, both of which are emitted mainly from vehicles exhaust pipes. On the other hand, trees are effective in reducing such contamination, so that they act as passive collectors of particulate matter. This work presents the results obtained from the first magnetic study of the particulate matter collected in two areas of the city of Santiago de Chile. Magnetic susceptibility and Saturation Isothermic Remanent Magnetization (SIRM) were determined in leaves from abundant urban trees and from urban dust samples. Results indicate that most of the samples contain ferromagnetic minerals with magnetite (Fe3O4) as the main carrier. Values of magnetic susceptibility (SI ×10-6 m3/kg) in the range 0.04-0.24 for leaves and in the range 10-45 for urban dust were determinated. In one of the city areas studied, significant correlation between the particulate matter deposited on leaves of Platanus orientalis and measured traffic flows was obtained. In addition, it was possible to estimate that the species Platanus orientalis and Acer negundo have a better ability to capture particulate matter than the species Robinia pseudoacacia.

  7. NKS NordRisk. Atlas of long-range atmospheric dispersion and deposition of radionuclides from selected risk sites in the Northern Hemisphere

    International Nuclear Information System (INIS)

    Havskov Soerensen, J.; Baklanov, A.; Mahura, A.; Lauritzen, Bent; Mikkelsen, Torben

    2008-07-01

    Within the NKS NordRisk project, 'Nuclear risk from atmospheric dispersion in Northern Europe', the NKS NordRisk Atlas has been developed. The atlas describes risks from hypothetical long-range atmospheric dispersion and deposition of radionuclides from selected nuclear risk sites in the Northern Hemisphere. A number of case studies of long-term long-range atmospheric transport and deposition of radionuclides has been developed, based on two years of meteorological data. Radionuclide concentrations in air and radionuclide depositions have been evaluated and examples of long-term averages of the dispersion and deposition and of the variability around these mean values are provided. (au)

  8. NKS NordRisk. Atlas of long-range atmospheric dispersion and deposition of radionuclides from selected risk sites in the Northern Hemisphere

    Energy Technology Data Exchange (ETDEWEB)

    Havskov Soerensen, J.; Baklanov, A.; Mahura, A. (Danish Meteorological Institute, Copenhagen (Denmark)); Lauritzen, Bent; Mikkelsen, Torben (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy, Roskilde (Denmark))

    2008-07-15

    Within the NKS NordRisk project, 'Nuclear risk from atmospheric dispersion in Northern Europe', the NKS NordRisk Atlas has been developed. The atlas describes risks from hypothetical long-range atmospheric dispersion and deposition of radionuclides from selected nuclear risk sites in the Northern Hemisphere. A number of case studies of long-term long-range atmospheric transport and deposition of radionuclides has been developed, based on two years of meteorological data. Radionuclide concentrations in air and radionuclide depositions have been evaluated and examples of long-term averages of the dispersion and deposition and of the variability around these mean values are provided. (au)

  9. Source of sulphur in the Ebro Basin (Northern Spain). Tertiary nonmarine evaporite deposits as evidenced by sulphur isotopes

    International Nuclear Information System (INIS)

    Birnbaum, S.J.; Coleman, D.

    1979-01-01

    The Ebro Basin is an intermontane basin, located in northern Spain, filled with Tertiary (largely Oligocene and Miocene) elastic and chemical deposits. Sulphur isotopes are utilized to determine the source of sulphur in the sulphate deposits (predominantly gypsum with accessory thenardite, mirabolite and epsomite). Data obtained from Tertiary gypsum rocks produce a range of delta 34 S values from +9.16% to + 14.02% with a mean of +13.61%. Data obtained from Triassic gypsum rocks (in source area) produce a range from +13.73% to +15.14%, with a mean of +14.66%. Values for Tertiary marine water range from +18% to +24%. These data indicate a nonmarine origin for sulpur within the Tertiary sulphate rocks. The contribution of Triassic sulphur to the groundwater system, plus varying degrees of dilution by isotopically lighter (atmospheric and sulphide) sulphur, best explains the isotopic ratios observed in the Tertiary Basin deposits. (Auth.)

  10. 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

    Science.gov (United States)

    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.

  11. Geochemical gradients within modern and fossil shells of Concholepas concholepas from northern Chile: an insight into U-Th systematics and diagenetic/authigenic isotopic imprints in mollusk shells

    Science.gov (United States)

    Labonne, Maylis; Hillaire-Marcel, Claude

    2000-05-01

    Seriate geochemical measurements through shells of one modern, one Holocene, and two Sangamonian Concholepas concholepas, from marine terraces of Northern Chile, were performed to document diagenetic vs. authigenic geochemical signatures, and to better interpret U-series ages on such material. Subsamples were recovered by drilling from the outer calcitic layer to the inner aragonitic layer of each of the studied shells. Unfortunately, this sampling procedure induces artifacts, notably the convertion of up to ˜20% of calcite into aragonite, and of up to ˜6% of aragonite into calcite, as well as in the epimerization of a few percent of isoleucine into D-alloisoleucine/ L-isoleucine. Negligible sampling artifacts were noticed for stable isotope and total amino acid contents. Diagenetic effects on the geochemical properties of the shells are particularly pronounced in the inner aragonitic layer and more discrete in the outer calcitic layer. The time-dependent decay of the organic matrix of the shell is illustrated by a one order of magnitude lower total amino acid content in the Sangamonian specimens by comparison with the modern shell. Conversely, the Sangamonian shells U contents increase by a similar factor and 13C- 18O enrichments as high as 2 to 3‰ seem also to occur through the same time interval possibly due to partial replacement of aragonite by gypsum. The decay of the organic matrix of the aragonitic layer of the shell is thought to play a major role with respect to U-uptake processes and stable isotope shifts. Nevertheless, asymptotic 230Th-ages (˜100 ka) in the inner U-rich layers of the Sangamonian shells, and 234U/ 238U ratios compatible with a marine origin for U, suggest U-uptake within a short diagenetic interval, when marine waters were still bathing the embedding sediment. Thus, U-series ages on fossil mollusks from such a hyper-arid environment should not differ much from the age of the corresponding marine unit deposition. However, the

  12. Aerobic ammonium oxidation in the oxycline and oxygen minimum zone of the eastern tropical South Pacific off northern Chile (˜20°S)

    Science.gov (United States)

    Molina, Verónica; Farías, Laura

    2009-07-01

    Aerobic NH 4+ oxidation rates were measured along the strong oxygen gradient associated with the oxygen minimum zone (OMZ) of the eastern tropical South Pacific off northern Chile (˜20°S) during 2000, 2003, and 2004. This process was examined by comparing NH 4+ rates of change during dark incubations, with and without the addition of allylthiourea, a classical inhibitor of the ammonia monooxygenase enzyme of ammonium-oxidizing bacteria. The contribution of aerobic NH 4+ oxidation in dark carbon fixation and NO 2- rates of change were also explored. Thirteen samples were retrieved from the oxycline (252 to ⩽5 μM O 2; 15 to ˜65 m depth) and three from the oxygen minimum core (⩽5 μM O 2; 100-200 m depth). Aerobic NH 4+ oxidation rates were mainly detected in the upper part (15-30 m depth) of the oxycline, with rates ranging from 0.16 to 0.79 μM d -1, but not towards the oxycline base (40-65 m depth). In the oxygen minimum core, aerobic NH 4+ oxidation was in the upper range and higher than in the upper part of the oxycline (0.70 and 1.0 μM d -1). Carbon fixation rates through aerobic NH 4+ oxidation ranged from 0.18 to 0.43 μg C L -1 d -1 and contributed between 33% and 57% of the total dark carbon fixation, mainly towards the oxycline base and, in a single experiment, in the upper part of the oxycline. NO 2- consumption was high (up to 10 μM d -1) towards the oxycline base and OMZ core, but was significantly reduced in experiments amended with allylthiourea, indicating that aerobic NH 4+ oxidation could contribute between 8% and 76% of NO 2- production, which in turn could be available for denitrifiers. Overall, these results support the important role of aerobic NH 4+ oxidizers in the nitrogen and carbon cycling in the OMZ and at its upper boundary.

  13. Intrusive hyaloclastite and peperitic breccias associated to sill and cryptodome emplacement on an Early Paleocene polymagmatic compound cone-dome volcanic complex from El Guanaco mine, Northern Chile

    Science.gov (United States)

    Páez, G. N.; Permuy Vidal, C.; Galina, M.; López, L.; Jovic, S. M.; Guido, D. M.

    2018-04-01

    This work explores the textural characteristics, morphology and facies architecture of well-preserved Paleocene hyaloclastic and peperitic breccias associated with subvolcanic intrusions at El Guanaco gold mine (Northern Chile). The El Guanaco mine volcanic sequence is part of a polymagmatic compound cone-dome volcanic complex grouping several dacitic domes and maar-diatremes, and subordinated subvolcanic intrusions of basaltic, andesitic and dacitic compositions. The Soledad-Peñafiel Fault System is a first order regional structure controlling the location and style of the volcanism in the region. Three different intrusive bodies (Basaltic sills, Dacitic cryptodomes and Andesitic cryptodomes) were found to intrude into a wet and poorly consolidated pyroclastic sequence representing the upper portions of a maar-diatreme. Consequently, extensive quench fragmentation and fluidization along their contacts occurred, leading to the formation of widespread breccia bodies enclosing a coherent nucleus. Differences in matrix composition allows to define two main breccias types: 1) poorly-sorted monomictic breccias (intrusive hyaloclastites) and 2) poorly-sorted tuff-matrix breccias (peperites). The observed facies architecture is interpreted as the result of the interplay of several factors, including: 1) magma viscosity, 2) the geometry of the intrusives, and 3) variations on the consolidation degree of the host rocks. Additionally, the overall geometry of each intrusive is interpreted to be controlled by the effective viscosity of the magmas along with the available magma volume at the time of the intrusions. The presence of three compositionally different subvolcanic bodies with intrusive hyaloclastite and peperite envelopes indicate, not only that all these intrusions occurred in a short period of time (probably less than 2-3 Ma), but also that the volcaniciclastic pile suffer little or none compaction nor consolidation during that time. The presence of three

  14. Permian depositional age of metaturbidites of the Duque de York Complex, southern Chile: U-Pb SHRIMP data and palynology

    International Nuclear Information System (INIS)

    Sepulveda, Fernando A; Palma-Heldt, Sylvia; Herve, Francisco; Fanning, Mark

    2010-01-01

    The Duque de York Complex (DYC) is part of the low grade metamorphic accretionary complexes of the pre-Andean Patagonian 'basement'. It is a sedimentary succession exposed along the western margin of southernmost South America. New U-Pb zircon ages and palynological data restrict the maximum depositional age of the DYC to the limit between the early Permian (Kungurian) and the middle Permian (Roadian). The palynological association recorded in the DYC, characterized mainly by Gymnospermopsida pollen, indicates a humid environment of forest with an under-growth of ferns. Regional paleogeographic correlations point out that an interpretation of DYC as an autochthonous terrane cannot be discarded, contrasting with previous hypotheses which suggest an allochthonous character for this complex

  15. General geology, alteration, and iron deposits in the Palaeoproterozoic Misi region, northern Finland

    Directory of Open Access Journals (Sweden)

    Tero Niiranen

    2003-01-01

    Full Text Available The Paleoproterozoic Misi region forms the northeastern part of the Peräpohja Schist Belt in northern Finland. The area comprises mafic volcanic and sedimentary rocks, differentiated gabbros, and late-orogenic granitoids. Three geochemically different mafic volcanic units were recognised: LREE-depleted amygdaloidal lavas, slightly LREE-enriched lavas, and mafic tuffs that have a flat REE pattern. Sedimentary rocks include arkosites, mica gneisses, dolomitic marbles, quartzites, tuffites, mica schists, calc-silicate rocks and graphite-bearing schists. Two types of gabbros wereidentified: one with a LREE-enriched pattern and another with flat REE pattern. The age of the former is according to Perttunen and Vaasjoki (2001 2117±4 Ma, whereas there is no age determination for the latter. The granitoid intrusions belong to the ca. 1800 Malate-orogenic group of the Central Lapland Granitoid Complex. The geochemistry and the stable isotope data on mafic lavas and dolomitic marbles show similarities with the mafic volcanic rocks and marbles of the lower part of the Kivalo group in the western part of Peräpohja Schist Belt. Peak metamorphic conditions in the region vary from upper-greenschist to upper-amphibolite facies. Three major stages of deformation were distinguished: N-S compressional D1 with ductile deformation, NE-SW compressional D2 with ductile to brittle-ductile deformation, and E-W compressional D3 with brittle deformation. Several magnetite occurrences are known in the region and four of those have been mined for iron. The ores are mainly composed of magnetite with minor haematite, pyrite, chalcopyrite and bornite. Besides iron, the ores contain small amounts of P, S and V aswell as trace amounts of Cu, Co, Te and Au. The magnetite bodies are hosted by skarnoids within the ca. 2220–2120 Ma dolomitic marble-quartzite sequence, and highly differentiated, intensely albitised, LREE-enriched gabbro. Multistage and -type alteration is

  16. Tufa in Northern England: depositional facies, carbonate mineral fabrics, and role of biomineralization

    Science.gov (United States)

    Manzo, E.; Mawson, M.; Perri, E.; Tucker, M. E.

    2009-04-01

    Tufas are widely scattered in northern England, being concentrated in areas of limestone (Carboniferous and Permian), where there are springs, seepages, streams and waterfalls with waters supersatured in respect of calcite. Some deposits are clearly related to faults. Tufas have been examined in Gordale and Malham (SW Yorkshire), Teesdale and Weardale (Co. Durham), Sunderland (Tyne & Wear) and Great Asby Fell (Cumbria). A variety of tufa types are developed: spring-related pisoids and moss tufa, fluviatile barrage and waterfall tufa, and seepage and spring tufa with microbial oncoids in a paludal setting. We present preliminary data and observations on tufa in the Teesdale area, which forms along the valley-side adjacent to the River Tees. Locally here, a tiny stream draining agricultural land runs over a sandstone outcrop at the top of a 30 metre high slope; water descends the 30-60 degrees slope, creating tiny waterfalls and pools across an area reaching 10 metres wide, on the way down towards the river. Three main facies are recognizable in the tufa deposits: carbonate crusts, moss tufa and pisoids. In the upper part of the slope tufa occurs as sub-vertical 0.5-5 cm thick carbonate crusts forming "sheets" with a bulbous external surface covered by a green biofilm, with some insect larvae. Encrustations form upon surfaces of rock exposures and pebbles, and coat plant fragments (leaves, twigs, pine cones). Tufa precipitation, particularly on mosses, liverworts and leaves (moss tufa), creates a series of rimmed pools, a few decimetres across and centimetres deep. Apart from the presence of moss, which gives the tufa has a vacuolar texture, the main constituents are cyanobacteria and diatoms. The moss tufa deposit may reach a metre or more in height and several metres in width, notably towards the base of the slope, adjacent to the river. Within the small pools on the slope, pisoids and partially calcified plant remains accumulate. They also occur abundantly in the

  17. Simulated nitrogen deposition causes a decline of intra- and extraradical abundance of arbuscular mycorrhizal fungi and changes in microbial community structure in northern hardwood forests

    Science.gov (United States)

    Linda T.A. van Diepen; Erik A. Lilleskov; Kurt S. Pregitzer; R. Michael Miller

    2010-01-01

    Increased nitrogen (N) deposition caused by human activities has altered ecosystem functioning and biodiversity. To understand the effects of altered N availability, we measured the abundance of arbuscular mycorrhizal fungi (AMF) and the microbial community in northern hardwood forests exposed to long-term (12 years) simulated N deposition (30 kg N ha-1...

  18. Tailings transport and deposition downstream of the Northern Hercules (Moline) mine in the catchment of the Mary River, Northern Territory

    International Nuclear Information System (INIS)

    Cull, R.F.; East, T.J.; Marten, R.; Murray, A.S.; Duggan, K.

    1986-01-01

    Milling of uraniferous and other metalliferous ores at the Northern Hercules (Moline) Mine near Pine Creek produced some 246,000 tonnes of tailings between 1959 and the closure of the mill in 1972. During this period tailings were contained by several bunds which later failed resulting in the erosion and transport of tailings by tributaries of the Mary River. Suspended sediment concentrations as high as 94 g/L were recorded in Tailings Creek immediately downstream of the eroding tailings pile during the 1984/85 wet season and the total yield was equivalent to a mean erosion rate for the tailings area of 4 mm/yr. This erosion rate is about two orders of magnitude higher than natural rates in the Pine Creek area. Erosion rates of the tailings pile have, however, decreased perhaps by as much as a factor of eight since the last bund was breached. Radioactive dose rates recorded along a series of transects across floodplains downstream of the mill are consistently related to the sedimentary environment. The main channel is associated with low dose rates, and the relatively low energy environments of backswamps and flood bypass channels are characterised by higher dose rates. Longitudinally, dose rates on the floodplain generally decrease with distance downstream although the rate of decrease is not constant, and appears to be dependent upon the hydrological and geomorphic character of the catchment

  19. Noble gas and halogen constraints on fluid sources in iron oxide-copper-gold mineralization: Mantoverde and La Candelaria, Northern Chile

    Science.gov (United States)

    Marschik, Robert; Kendrick, Mark A.

    2015-03-01

    The noble gas (Ar, Kr, Xe) and halogen (Cl, Br, I) composition of fluid inclusions in hydrothermal quartz and calcite related to the hypogene iron oxide-copper-gold (IOCG) mineralization at Mantoverde and Candelaria, Chile, have been investigated to provide new insights of fluid and salinity sources in Andean IOCG deposits. A combination of mechanical extraction by crushing and thermal decrepitation methods was applied and collectively indicate that fluid inclusions with salinities ranging from 3.4 up to 64 wt% NaCl equivalent have molar Br/Cl and I/Cl ratios of between 0.5 × 10-3 and 3.0 × 10-3 and I/Cl of between 8 × 10-6 and 25 × 10-6 in the majority of samples, with maximum values of 5.2 × 10-3 obtained for Br/Cl and 64 × 10-6 for I/Cl in fluid inclusions within individual samples. The fluid inclusions have age-corrected 40Ar/36Ar ratios ranging from the atmospheric value of 296 up to 490 ± 45, indicating the presence of crustal- or mantle-derived excess 40Ar in the fluid inclusions of most samples. The fluid inclusions have 84Kr/36Ar and 130Xe/36Ar ratios intermediate of air and air-saturated water. However, 40Ar/36Ar is not correlated with either 84Kr/36Ar or 130Xe/36Ar, and the fluid inclusion 36Ar concentrations of 0.2-3.5 × 10-10 mol/g (calculated from measured Cl/36Ar and thermometric salinity measurements) extend below the seawater value of 0.34 × 10-10 mol/g, suggesting that contamination with modern air is a minor artifact. The range of fluid inclusion Br/Cl and I/Cl ratios overlap those previously documented for the mantle and magmatic-hydrothermal ore deposits, and the fluids' unusually low 36Ar concentration is consistent with the involvement of magmatic-hydrothermal fluids. Input of additional non-magmatic fluid components is suggested by the spread in Br/Cl and I/Cl to values characteristic of bittern brine sedimentary formation waters and near atmospheric 40Ar/36Ar. These data are compatible with mixing of magmatic-hydrothermal fluids

  20. Simulated nitrogen deposition affects community structure of arbuscular mycorrhizal fungi in northern hardwood forests

    Science.gov (United States)

    Linda T.A. Van Diepen; Erik Lilleskov; Kurt S. Pregitzer

    2011-01-01

    Our previous investigation found elevated nitrogen deposition caused declines in abundance of arbuscular mycorrhizal fungi (AMF) associated with forest trees, but little is known about how nitrogen affects the AMF community composition and structure within forest ecosystems. We hypothesized that N deposition would lead to significant changes in the AMF community...

  1. Impact of enhanced ozone deposition and halogen chemistry on tropospheric ozone over the Northern Hemisphere

    Science.gov (United States)

    Fate of ozone in marine environments has been receiving increased attention due to the tightening of ambient air quality standards. The role of deposition and halogen chemistry is examined through incorporation of an enhanced ozone deposition algorithm and inclusion of halogen ch...

  2. Case history of the discovery of the Jabiluka uranium deposits, East Alligator River region, Northern Territory of Australia

    International Nuclear Information System (INIS)

    Rowntree, J.C.; Mosher, D.V.

    1976-01-01

    Pancontinental Mining Limited acquired exploration rights over an area in the East Alligator River Region, Northern Territory, Australia, in 1970. Subsequently, Getty Oil Development Company Limited acquired a substantial minority interest in the property. The Jabiluka deposits were discovered during the course of exploration and are currently the largest of the four major uranium deposits in the East Alligator River Region. This region at present contains 24% of the western world's reasonably assured resources of uranium. The exploration techniques employed during primary and secondary exploration on the property between 1971 and 1975 and during the delineation of the Jabiluka deposits are discussed in detail. The case history illustrates the exploration philosophy which was successfully employed on the Jabiluka property. The philosophy encompasses the following points: The need for an assessment on the limits of airborne radiometric surveys; the necessity for detection and evaluation of point source anomalies; the necessity for exploration along extensions of favourable lithologies; and the desirability of modification of exploration techniques on different types of anomalies. Some aspects of this philosophy may be useful in exploration for similar stratabound uranium deposits in other areas. (author)

  3. 87Sr/86Sr in gypsic soils of hyperarid settings as an altitude proxy: results for northern Chile (19-22°S) and paleoaltimetry applications

    Science.gov (United States)

    Cosentino, N. J.; Jordan, T. E.; Derry, L. A.

    2012-12-01

    Quantification of uplift of a continental surface relative to sea level is still challenging. We have developed a new altimeter based on the 87Sr/86Sr ratio of modern accumulations of salts (incipient soils) in hyperarid settings like those present in northern Chile's Atacama Desert, which lies in the forearc of the Nazca-South America plate system. The proposed altimeter is based on the first order topographic control on the extent of coastal fog. Advective events bring offshore-generated stratocumulus clouds to the continent, generating fog between 400 and 1100 m.a.s.l.. In the hyperarid desert, thin layers of calcium sulfate, among other salts, accumulate on the surface. The main sources of the calcium sulfates are i) Pacific-sourced fog that transports aerosols and dissolved salts inland, which are precipitated upon evaporation, ii) wind that transports salts derived from the weathering of Andean magmatic arc rocks, which may be recycled through salars, and to a lesser extent, iii) salts derived from volcanic emissions. While the latter two have an average 87Sr/86Sr isotopic ratio of 0.70749, the fog source has a value corresponding to seawater (0.70917). Due to the high atomic weight of Sr and to the low relative mass difference of isotopes 87Sr and 86Sr, environmental isotopic fractionation is minimal. This makes 87Sr/86Sr an excellent proxy for the primary source of the calcium sulfates and the calcium sulfates' Sr. Samples from four E-W transects of the forearc between 19.75° to 23.75° S demonstrate variations in 87Sr/86Sr for altitudes between 200 and 2700 m.a.s.l.. There is a correlation between the modern salts' 87Sr/86Sr and its altitude of formation for altitudes between ~400 and ~800 m.a.s.l., above which the 87Sr/86Sr falls abruptly until reaching values similar to or lower than the Andean average. The fact that this correlation is observed for the whole dataset (including all four transects) suggests that the relationship is regional rather than

  4. Microfaunal analysis of late Quaternary deposits of the northern Bering Sea.

    Science.gov (United States)

    McDougall, K.

    1982-01-01

    Holocene microfaunal associations and distribution patterns define three inner-shelf (1-20m) biofacies in Norton Sound, northern Bering Sea. The Holocene facies relations are the basis for interpreting early Holocene and late Pleistocene environmental conditions in the NE Bering Sea area. Norton Sound cores provide evidence of two marine transgressions and a varying river input.-from Author

  5. Surface ozone seasonality under global change: Influence from dry deposition and isoprene emissions at northern mid-latitudes

    Science.gov (United States)

    Clifton, O.; Paulot, F.; Fiore, A. M.; Horowitz, L. W.; Malyshev, S.; Shevliakova, E.; Correa, G. J. P.; Lin, M.

    2017-12-01

    Identifying the contributions of nonlinear chemistry and transport to observed surface ozone seasonal cycles over land using global models relies on an accurate representation of ozone uptake by vegetation (dry deposition). It is well established that in the absence of ozone precursor emission changes, a warming climate will increase surface ozone in polluted regions, and that a rise in temperature-dependent isoprene emissions would exacerbate this "climate penalty". However, the influence of changes in ozone dry deposition, expected to evolve with climate and land use, is often overlooked in air quality projections. With a new scheme that represents dry deposition within the NOAA GFDL dynamic vegetation land model (LM3) coupled to the NOAA GFDL atmospheric chemistry-climate model (AM3), we simulate the impact of 21st century climate and land use on ozone dry deposition and isoprene emissions. This dry deposition parameterization is a version of the Wesely scheme, but uses parameters explicitly calculated by LM3 that respond to climate and land use (e.g., stomatal conductance, canopy interception of water, leaf area index). The parameterization includes a nonstomatal deposition dependence on humidity. We evaluate climatological present-day seasonal cycles of ozone deposition velocities and abundances with those observed at northern mid-latitude sites. With a set of 2010s and 2090s decadal simulations under a high climate warming scenario (RCP8.5) and a sensitivity simulation with well-mixed greenhouse gases following RCP8.5 but air pollutants held at 2010 levels (RCP8.5_WMGG), we examine changes in surface ozone seasonal cycles. We build on our previous findings, which indicate that strong reductions in anthropogenic NOx emissions under RCP8.5 cause the surface ozone seasonal cycle over the NE USA to reverse, shifting from a summer peak at present to a winter peak by 2100. Under RCP8.5_WMGG, we parse the separate effects of climate and land use on ozone dry

  6. Source contribution to the bulk atmospheric deposition of minor and trace elements in a Northern Spanish coastal urban area

    Science.gov (United States)

    Fernández-Olmo, Ignacio; Puente, Mariano; Montecalvo, Lucia; Irabien, Angel

    2014-08-01

    The bulk atmospheric deposition of the minor and trace elements As, Cd, Cr, Cu, Mn, Mo, Ni, Pb, Ti, V and Zn was investigated in Santander, a Northern Spanish coastal city. Bulk deposition samples were collected monthly for three years using a bottle/funnel device. Taking into account that heavy metals are bioavailable only in their soluble forms, water-soluble and water-insoluble fractions were evaluated separately for element concentration. The fluxes of the studied elements in the bulk deposition exhibited the following order: Zn > Mn ≫ Cu > Cr > Pb > V > Ni ≫ As > Mo > Cd. The fluxes of Zn and Mn were more than 10 times higher than those of the other elements, with maximum values of 554.5 and 334.1 μg m- 2 day- 1, respectively. Low solubilities (below 22%) were found for Cr, Ti and Pb, whereas the highest solubility was found for Zn (78%). With the exception of Cu, all of the studied metals in the water-soluble fraction of the atmospheric deposition showed seasonal dependence, due to the seasonal variability of precipitation. The enrichment factors (EFs) of Cu, Cd and Zn were higher than 100, indicating a clear anthropogenic origin. The EF of Mn (50) was below 100, but an exclusively industrial origin is suggested. Positive Matrix Factorisation (PMF) was used for the source apportionment of the studied minor and trace elements in the soluble fraction. Four factors were identified from PMF, and their chemical profiles were compared with those calculated from known sources that were previously identified in Santander Bay: two industrial sources, the first of which was characterised by Zn and Mn, which contributes 62.5% of the total deposition flux of the studied elements; a traffic source; and a maritime source. Zinc and Mn are considered to be the most characteristic pollutants of the studied area.

  7. 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

  8. NKS NordRisk II: Atlas of long-range atmospheric dispersion and deposition of radionuclides from selected risk sites in the Northern Hemisphere

    DEFF Research Database (Denmark)

    Smith Korsholm, Ulrik; Astrup, Poul; Lauritzen, Bent

    The present atlas has been developed within the NKS/NordRisk-II project "Nuclear risk from atmospheric dispersion in Northern Europe". The atlas describes risks from hypothetical long-range dispersion and deposition of radionuclides from 16 nuclear risk sites on the Northern Hemisphere...... spanning the climate variability associated with the North Atlantic Oscillation, and corresponding time evolution of the ensemble mean atmospheric dispersion....

  9. The computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in Northern Xinjiang, China

    Energy Technology Data Exchange (ETDEWEB)

    Zhengbang, Wang; Mingkuan, Qin; Ruiquan, Zhao; Shenghuang, Tang [Beijing Research Inst. of Uranium Geology, CNNC (China); Baoqun, Wang; Shuangxing, Lin [Geo-prospecting Team No. 216, CNNC (China)

    2001-08-01

    The process of establishment of the model includes following steps: (1) Systematically studying a known typical in-situ leachable sandstone type uranium deposit--Deposit No. 512 in Yili basin, analyzing its controlling factors and establishing its metallogenetic model; (2) Establishing the metallogenetic models of this type of uranium deposit and uranium-bearing area on the basis of comparison study on the deposit No. 512 with the same type uranium deposits in the world; (3) Creating the computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in northern Xinjiang; (4) Determining the standards of giving a evaluation-mark for each controlling factor of in-situ leachable sandstone type uranium deposit and uranium-bearing area; (5) Evaluating uranium potential and prospect of the unknown objective target.

  10. The computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in Northern Xinjiang, China

    International Nuclear Information System (INIS)

    Wang Zhengbang; Qin Mingkuan; Zhao Ruiquan; Tang Shenghuang; Wang Baoqun; Lin Shuangxing

    2001-01-01

    The process of establishment of the model includes following steps: (1) Systematically studying a known typical in-situ leachable sandstone type uranium deposit--Deposit No. 512 in Yili basin, analyzing its controlling factors and establishing its metallogenetic model; (2) Establishing the metallogenetic models of this type of uranium deposit and uranium-bearing area on the basis of comparison study on the deposit No. 512 with the same type uranium deposits in the world; (3) Creating the computerized semi-quantitative comprehensive identification-evaluation model for the large-sized in-situ leachable sandstone type uranium deposits in northern Xinjiang; (4) Determining the standards of giving a evaluation-mark for each controlling factor of in-situ leachable sandstone type uranium deposit and uranium-bearing area; (5) Evaluating uranium potential and prospect of the unknown objective target

  11. Uranium deposits in the Beaverlodge area, northern Saskatchewan: their relationship to the Martin Group (Proterozoic) and the underlying basement

    International Nuclear Information System (INIS)

    Mazimhaka, P.K.; Hendry, H.E.

    1989-01-01

    The rocks of the Martin Group crop out in an area 60 km by 50 km north of Lake Athabasca near Uranium City, northern Saskatchewan. This area has numerous uranium showings within a few kilometres of the unconformity below the Martin Group. Mineralization occurs in fault zones, in basement rocks and in sedimentary and volcanic rocks of the Martin Group. Martin Group sediments accumulated in alluvial fans, braided streams, and ephemeral lakes. The thickest sequence (8 km to 10 km) is preserved in the Beaverlodge area, near Uranium City. The style of sedimentation changed through time as the basin evolved from deposition of conglomeratic detritus along fault scarps to the accumulation of silt in ephemeral lakes. The uneven nature of the sub-Martin unconformity surface, the lithotype of the lowermost conglomerates and breccias (Beaverlodge Formation), and the shape of the basin fill indicate deposition in fault-controlled basins. The earliest economic uranium mineralization in the rocks of the Martin Group was epigenetic. The mineralization was coeval with that in basement rocks. Economic mineralization in basement rocks and in the lowermost formation of the Martin Group is close to the unconformity. Epigenetic uranium mineralization thus appears to have resulted from processes that were related, in time and space, to either the formation of the unconformity or the deposition of the Martin Group or both. (author). 29 refs, 5 figs

  12. The Application of Borehole Seismic Techniques in Mine Development at the Millennium Uranium Deposit, Northern Saskatchewan, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Wood, G.; O’Dowd, C., E-mail: garnet_wood@cameco.com [Cameco Corporation, Saskatoon, Saskatchewan (Canada); Cosma, C.; Enescu, N. [Vibrometric Canada Ltd., Toronto, Ontario (Canada)

    2014-05-15

    The Millennium uranium deposit is located within the Athabasca Basin of northern Saskatchewan, Canada. The deposit is situated in metasedimentary rocks, is controlled by multiple sub-vertical faults, and crossfaults and is overlain by over 500 m of intensely altered, porous Manitou Falls group sandstones. The rock quality directly surrounding the deposit is greatly reduced because of alteration and post-Athabasca sandstone structures, which provide conduits for the migration of basinal and meteoric fluids. This leads to significant risk for mine development and shaft sinking, because of the increased potential for water inflow into mine workings. To mitigate the risk involved with mining in such complex geology several projects were proposed as part of a pre-feasibility study. Of these, seismic methods were identified as the best tool to potentially identify alteration and structurally compromised zones. Subsequently, a comprehensive surface and borehole seismic program was completed in an attempt to delineate these engineering hazards and to provide assurance of success of the shaft sinking and mine development. This was the first time a seismic program of this scale was undertaken for geotechnical studies during mine development in the Athabasca Basin. (author)

  13. Dynamic modelling of atmospherically-deposited Ni, Cu, Zn, Cd and Pb in Pennine catchments (northern England)

    International Nuclear Information System (INIS)

    Tipping, E.; Rothwell, J.J.; Shotbolt, L.; Lawlor, A.J.

    2010-01-01

    Simulation modelling with CHUM-AM was carried out to investigate the accumulation and release of atmospherically-deposited heavy metals (Ni, Cu, Zn, Cd and Pb) in six moorland catchments, five with organic-rich soils, one with calcareous brown earths, in the Pennine chain of northern England. The model considers two soil layers and a third layer of weathering mineral matter, and operates on a yearly timestep, driven by deposition scenarios covering the period 1400-2010. The principal processes controlling heavy metals are competitive solid-solution partitioning of solutes, chemical interactions in solution, and chemical weathering. Agreement between observed and simulated soil metal pools and surface water concentrations for recent years was generally satisfactory, the results confirming that most contemporary soil metal is from atmospheric pollution. Metals in catchments with organic-rich soils show some mobility, especially under more acid conditions, but the calcareous mineral soils have retained nearly all anthropogenic metal inputs. Complexation by dissolved organic matter and co-transport accounts for up to 80% of the Cu in surface waters. - CHUM-AM is applied to six differing moorland catchments to account for the accumulation and leaching of atmospherically-deposited trace metals over the past several centuries.

  14. Dynamic modelling of atmospherically-deposited Ni, Cu, Zn, Cd and Pb in Pennine catchments (northern England)

    Energy Technology Data Exchange (ETDEWEB)

    Tipping, E., E-mail: et@ceh.ac.u [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Rothwell, J.J. [Upland Environments Research Unit, School of Environment and Development, University of Manchester, Manchester M13 9PL (United Kingdom); Shotbolt, L. [Geography Department, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Lawlor, A.J. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)

    2010-05-15

    Simulation modelling with CHUM-AM was carried out to investigate the accumulation and release of atmospherically-deposited heavy metals (Ni, Cu, Zn, Cd and Pb) in six moorland catchments, five with organic-rich soils, one with calcareous brown earths, in the Pennine chain of northern England. The model considers two soil layers and a third layer of weathering mineral matter, and operates on a yearly timestep, driven by deposition scenarios covering the period 1400-2010. The principal processes controlling heavy metals are competitive solid-solution partitioning of solutes, chemical interactions in solution, and chemical weathering. Agreement between observed and simulated soil metal pools and surface water concentrations for recent years was generally satisfactory, the results confirming that most contemporary soil metal is from atmospheric pollution. Metals in catchments with organic-rich soils show some mobility, especially under more acid conditions, but the calcareous mineral soils have retained nearly all anthropogenic metal inputs. Complexation by dissolved organic matter and co-transport accounts for up to 80% of the Cu in surface waters. - CHUM-AM is applied to six differing moorland catchments to account for the accumulation and leaching of atmospherically-deposited trace metals over the past several centuries.

  15. 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.

  16. Oxygen at Nanomolar Levels Reversibly Suppresses Process Rates and Gene Expression in Anammox and Denitrification in the Oxygen Minimum Zone off Northern Chile

    OpenAIRE

    Dalsgaard, Tage; Stewart, Frank J.; Thamdrup, Bo; De Brabandere, Loreto; Revsbech, Niels Peter; Ulloa, Osvaldo; Canfield, Don E.; DeLong, Edward

    2014-01-01

    A major percentage (20 to 40%) of global marine fixed-nitrogen loss occurs in oxygen minimum zones (OMZs). Concentrations of O[subscript 2] and the sensitivity of the anaerobic N[subscript 2]-producing processes of anammox and denitrification determine where this loss occurs. We studied experimentally how O[subscript 2] at nanomolar levels affects anammox and denitrification rates and the transcription of nitrogen cycle genes in the anoxic OMZ off Chile. Rates of anammox and denitrification w...

  17. Deposition Velocities of C1 - C5 Alkyl Nitrates at a Northern Colorado Site

    Science.gov (United States)

    Abeleira, A.; Sive, B. C.; Farmer, D.; Swarthout, B.

    2017-12-01

    Organic nitrates (RONO2) are ubiquitous in the troposphere and are part of gas-phase oxidized nitrogen (NOy = NOx + HNO3 + HONO + N2O5 + HO2NO2 + PAN + NO3 + RONO2). RONO2 can act as both sinks and sources of HOx (RO + RO2 + OH) and NOx (NO + NO2), contributing to the nonlinearity of ozone (O3) formation. It is thus potentially important to understand sinks of RONO2, and how they change seasonally, in order to predict O3 on local, regional and global scales. We focus here on speciated C1 - C5 monofunctional alkyl nitrates (C1 - C5 ANs). In polluted continental regions the dominant source of C1 - C5 ANs is the OH-initiated oxidation of parent alkanes in the presence of NO, and thus changes seasonally with OH mixing ratios. Direct emissions of C1 - C2 ANs include oceanic sources and biomass burning. The sinks of C1 - C5 ANs include OH oxidation and photolysis, both of which release O3 precursors. Chemical transport models tend to overestimate the mixing ratios of small ANs indicating that a missing sink is not included. Wet deposition of C1 - C5 ANs is typically ignored due to the very low Henry's Law constants of these species. However, dry deposition of total organic nitrogen has been observed to be substantial. The dry deposition velocity of methyl nitrate has previously been estimated from summer observations at a rural New England site with a value of 0.13 cm s-1. Here we report deposition velocities for C1 - C5 ANs from surface observations at the Boulder Atmospheric Observatory (BAO) in Erie, Colorado during winter 2011 and spring 2015. We calculate deposition velocities from the observed decay in C1 - C5 ANs at night during periods with a stable nocturnal boundary layer height of 100 - 200 meters. Ideal meteorological conditions were observed for 5 nights during the 2011 NACHTT campaign (February - March 2011), and for 5 nights during the 2015 SONGNEX campaign (March - May 2015). Deposition velocities increased with alkyl nitrate size, ranging from 0.15 cm

  18. Fluid inclusion and oxygen isotope studies of the Nabarlek and Jabiluka uranium deposits, Northern Territory, Australia

    International Nuclear Information System (INIS)

    Ypma, P.J.M.; Fuzikawa, K.

    1980-01-01

    We lack a basic understanding of the solutions producing the uranium deposits of the Alligator Rivers Uranium Field (ARUF). Several theories have been proposed ranging from syngenetic, epigenetic hydrothermal, epigenetic metamorphogenic, surficial origin (Ferguson et al., this volume), and mobilization by evaporite deposits. As for a precipitation mechanism, we do not seem to find much beyond the presence of graphite in some ore-bearing and intra-formational strata, and pre-uranium sulphides, none of which reducing factors are common throughout all ore bodies. This study was initiated with the aim of obtaining direct fluid inclusion evidence of the solution transport and precipitation of uranium

  19. Hippidion saldiasi Roth, 1899 (Mammalia, Perissodactyla en el Pleistoceno tardío de Calama, norte de Chile Late Pleistocene Hippidion saldiasi Roth, 1899 (Mammalia, Perissodactyla from Calama, northern Chile

    Directory of Open Access Journals (Sweden)

    MARÍA TERESA ALBERDI

    2007-06-01

    Full Text Available Se describen restos del género Hippidion procedentes de la zona del desierto de Atacama (Calama, Segunda Región de Chile. El conjunto analizado corresponde a un esqueleto bastante completo proveniente del yacimiento Betecsa 1, así como escasas unidades del yacimiento Kamac Mayu. En ambos sitios se identifica H. saldiasi. A partir de dos dataciones radiométricas por AMS del ejemplar estudiado, los restos se sitúan estratigráficamente en el Pleistoceno Superior (21.070 ± 100 AP y 21.380 ± 100 14C AP. Se infieren datos ambientales y de dieta a partir de análisis de isótopos estables en los restos de Hippidion saldiasi del sitio Betecsa 1 cuyo valor de δ13C en hueso fue de -15,45 y el valor en esmalte de dientes fue de -16,68, sugiriendo una alimentación con pastos C3. El cráneo recuperado es el primero conocido de esta especieThis paper describes the Hippidion bones recovered from the Atacama Desert (Calama, Second Region of Chile. The analyzed assemblage corresponds to a nearly complete skeleton from Betecsa 1 site and more poorly preserved remains from Kamac Mayu site. In both H. saldiasi is identified. Two 14C radiometric determinations indicate late Pleistocene age for these remains (21,070 ± 100 BP and 21,380 ± 100 BP. Environmental and diet inferences from stable isotope analysis are also presented. The δ13C value from Betecsa 1 horses (-15.45 from bone sample and -16.68 from enamel sample suggest a dietary adaptation exclusively C3 feeders. This is the first skull and associated skeleton recovered of this species

  20. Tectonic and climatic controls on continental depositional facies in the Karoo Basin of northern Natal, South Africa

    Science.gov (United States)

    Turner, Brian R.

    1986-02-01

    The eastern Karoo Basin, South Africa, contains a thick sequence of terrigenous clastic sediments comprising a meanderbelt facies, braided channel facies divided into coarse and fine subfacies, fluviolacustrine facies and aeolian facies. Depositional trends and changes in fluvial style reflect a progressive increase in aridity of the climate under stable tectonic conditions, interrupted by two phases of source area tectonism and the development of fine and coarse clastic wedges of the braided channel subfacies; the latter signifying a short interlude of cool, wet conditions. The fine braided channel subfacies occurs in the upper part of the meanderbelt facies, which was deposited by ephemeral, meandering mixed-load streams of variable discharge and sinuosity, under dry, semi-arid climatic conditions. These deposited complex, internally discordant channel sands and well-developed levee deposits. Following deposition of the coarse braided channel subfacies semi-arid conditions returned and fluvial deposition was dominated by ephemeral, straight to slightly sinuous mixed load streams characterised by simple channel sand bodies. As the aridity of the climate increased, the streams became more localised and carried an increasing proportion of fines. Interbedded with and overlying the fluvial deposits is a mudstone-dominated lacustrine sequence grading up into aeolian sands suggesting a playa lake-type situation. The general absence of evaporites from these sediments is attributed to the fresh nature of the lake waters, as evidenced by the freshwater aquatic organisms and clay-mineral suite, the lack of adequate inflow for solute accumulation and the removal of dust impregnated by salts from the surface of the dry lake bed during the dry season by superheated, upward-spiralling columns of air. Broadly similar environments to the fluvio-lacustrine and aeolian facies sequence are to be found in the Lake Eyre Basin of central Australia and the Okavango "delta" of northern

  1. The Upper Devonian deposits in the northern part of Leon (Cantabrian Mountains, Northwestern Spain)

    NARCIS (Netherlands)

    Loevezijn, van G.B.S.; Raven, J.G.M.

    1983-01-01

    During the Late Devonian, deposition in the Cantabrian Mountains was largely controlled by movements along faults. By way of intermitting subsidence of the area south of the Sabero-Gordón line and the connected progradation of the coast during the Frasnian and early Famennian, three regressive

  2. Comparisons of measured and modelled ozone deposition to forests in northern Europe

    DEFF Research Database (Denmark)

    Touvinen, J. P.; Simpson, D.; Mikkelsen, Teis Nørgaard

    2001-01-01

    The performance of a new dry deposition module, developedfor the European-scale mapping and modelling of ozone flux to vegetation, was tested against micrometeorological ozone and water vapour flux measurements. The measurement data are for twoconiferous (Scots pine in Finland, Norway spruce...

  3. Quantification of surface uplift by using paleo beach deposits (Oman, Northern Indian Ocean)

    Science.gov (United States)

    Hoffmann, Gösta; Schneider, Bastian; Monschau, Martin; Mechernich, Silke

    2017-04-01

    The study focusses on a coastal area along the Arabian Sea in Oman. Here, a staircase of marine terraces is seen as geomorphological evidence suggesting sub-recent uplift of a crustal block in the northeast of the Arabian Peninsula. The erosional terraces are cut into Paleocene to Early Eocene limestone formations. These limestone formations are underlain by allochtonous ophiolites. We mapped the terraces over a distance of 60 km and identified at least 8 terrace levels in elevations up to 350 m above present sea level. The uppermost terraces are erosional, whereas the lower ones are depositional in style. Mollusc and coral remains as well as beach-rock are encountered on the terrace surfaces. The formations are dissected by NW-SE trending faults. Some of the terraces are very pronounced features in the landscape and easy to trace, others are partly eroded and preserved as remnants only. The deposit along the shoreline angle act as a datum making use of the fact that the rocks formed in a defined horizontal level which is the paleo-sea level. Hence, any offset from the primary depositional level is evidence for neotectonic movements. We utilise differential GPS to map the elevation of beachrock deposits. Age constraints on terrace formation is derived by sampling the beachrock deposits and dating using cosmogenic nuclii. The results indicate ongoing uplift in the range of less than a millimetre per year. The uplift is differential as the terraces are tilted. We mapped oblique normal and strike-slip faults in the younger terraces. We hypothesise that the mechanism responsible for the uplift is not tectonics but driven by the serpentinisation of the ophiolite that underlie the limestone formations. One process during the serpentinisation is the hydration of the mantle rocks which is responsible for a decrease in density. The resulting buoyancy and significant solid volume increase lead to the observed deformation including uplift.

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

    Science.gov (United States)

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

    2015-12-01

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

  5. 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

    Directory of Open Access Journals (Sweden)

    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.

  6. Task 50 - deposition of lignites in the Fort Union Group and related strata of the northern Great Plains

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, J.H.; Roth, B.; Kihm, A.J.

    1997-08-11

    Late Cretaceous, Paleocene, and early Eocene geologic and paleontologic studies were undertaken in western North Dakota, eastern and south-central Montana, and northwestern and northeastern Wyoming. These study areas comprise the Williston, Bighorn, and Powder River Basins, all of which contain significant lignite resources. Research was undertaken in these basins because they have the best geologic sections and fossil record for the development of a chronostratigraphic (time-rock) framework for the correlation of lignite beds and other economic resources. A thorough understanding of the precise geologic age of the deposition of sediments permits a powerful means of interpreting the record of geologic events across the northern Great Plains. Such an understanding allows for rigorous interpretation of paleoenviromnents and estimates of resource potential and quality in this area of economically significant deposits. This work is part of ongoing research to document change in the composition of molluscan fossil faunas to provide a paleoenvironmentally sensitive independent means of interpreting time intervals of brief duration during the Late Cretaceous, Paleocene, and Eocene. This study focuses on the record of mollusks and, to a lesser extent, mammals in the (1) Hell Creek-Tullock Formations, which include the Cretaceous-Paleocene boundary, in the western portion of the Williston Basin, Montana; (2) uppermost Cretaceous, Paleocene, and lowermost Eocene strata in western North Dakota, which -includes the last interior seaway in North Dakota; (3) upper Paleocene and lowermost Eocene of the northern portion of the Bighorn Basin of south-central Montana and northwestern Wyoming; and (4) Powder River Basin of northeastern Wyoming and southeastern Montana. The geologic record provides different physical and paleontological information to aid in interpreting the geologic record through the study interval.

  7. New insights into trace elements deposition in the snow packs at remote alpine glaciers in the northern Tibetan Plateau, China.

    Science.gov (United States)

    Dong, Zhiwen; Kang, Shichang; Qin, Xiang; Li, Xiaofei; Qin, Dahe; Ren, Jiawen

    2015-10-01

    Trace element pollution resulting from anthropogenic emissions is evident throughout most of the atmosphere and has the potential to create environmental and health risks. In this study we investigated trace element deposition in the snowpacks at two different locations in the northern Tibetan Plateau, including the Laohugou (LHG) and the Tanggula (TGL) glacier basins, and its related atmospheric pollution information in these glacier areas, mainly focusing on 18 trace elements (Li, Be, V, Cr, Co, Ni, Cu, Zn, Ga, Rb, Nb, Mo, Cd, Sb, Cs, Ba, Tl, and Pb). The results clearly demonstrate that pronounced increases of both concentrations and crustal enrichment factors (EFs) are observed in the snowpack at the TGL glacier basin compared to that of the LHG glacier basin, with the highest EFs for Sb and Zn in the TGL basin, whereas with the highest EFs for Sb and Cd in the LHG basin. Compared with other studies in the Tibetan Plateau and surrounding regions, trace element concentration showed gradually decreasing trend from Himalayan regions (southern Tibetan Plateau) to the TGL basin (central Tibetan Plateau), and to the LHG basin (northern Tibetan Plateau), which probably implied the significant influence of atmospheric trace element transport from south Asia to the central Tibetan Plateau. Moreover, EF calculations at two sites showed that most of the heavy metals (e.g., Cu, Zn, Mo, Cd, Sb, and Pb) were from anthropogenic sources and some other elements (e.g., Li, Rb, and Ba) were mainly originated from crustal sources. MODIS atmospheric optical depth (AOD) fields derived using the Deep Blue algorithm and CALIOP/CALIPSO transect showed significant influence of atmospheric pollutant transport from south Asia to the Tibetan Plateau, which probably caused the increased concentrations and EFs of trace element deposition in the snowpack on the TGL glacier basin. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. 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

  9. 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

    Directory of Open Access Journals (Sweden)

    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

  10. Gold deposit styles and placer gold characterisation in northern and east-central Madagascar

    Science.gov (United States)

    Pitfield, Peter E. J; Styles, Michael T.; Taylor, Cliff D.; Key, Roger M.; Bauer,; Ralison, A

    2009-01-01

    Microchemical characterisation of bedrock and placer gold grains from six gold districts within the Archaean domains and intervening Neoproterozoic Anaboriana-Manampotsy belt of northern and east-central Madagascar show few opaque inclusions (e.g pyrrhotite, Bi tellurides) but wide range of Ag contents (40wt%). Some districts exhibit multiple source populations of grains. The ‘greenstone belt’ terranes have an orogenic gold signature locally with an intrusion-related to epithermal overprint. Proterozoic metasediments with felsic to ultramafic bodies yield dominantly intrusion-related gold. A high proportion of secondary gold (<0.5wt% Ag) is related to recycling of paleoplacers and erosion of post-Gondwana planation surfaces and indicates that some mesothermal gold systems were already partially to wholly removed by erosion by the PermoTriassic.

  11. Optimal geophysical complex and methods for investigation of peleogene and upper cretaceous deposits in search and exploratory wells in the northern areas of Tumen region

    International Nuclear Information System (INIS)

    Nelepchenko, O.M.; Akhiyarov, V.Kh.

    1975-01-01

    A number of geophysical studies of the Paleogene and upper Cretaceous deposits in prospecting and exploration boreholes in the northern part of the Tyumen field are described. The studies include, besides the essential ones, neutron logging with thermal neutrons (NKT-50), infrared logging, and lateral logging

  12. Atmospheric deposition and canopy exchange processes in alpine forest ecosystems (northern Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Balestrini, R. [Water Research Institute, Brugherio (Italy); Tagliaferri, A. [Regional Forestry Board (Italy)

    2001-07-01

    Throughfall and bulk precipitation chemistry were studied for five years (June 1994-May 1999) at two high elevation forest sites (Val Gerola and Val Masino) which were known to differ in terms of tree health, as assessed by live crown condition. The ion concentration of bulk precipitation samples did not differ significantly between sites, except for Mg{sup 2+}, while the throughfall concentrations differed in the measured values of H{sup +}, N-NO{sub 3}{sup -}, Cl{sup -}, Na{sup +}, K{sup +}, DOC and weak organic acids. The results of the application of the canopy exchange model indicated a higher contribution from the dry deposition of N-NO{sub 3}{sup -}, N-NH{sub 4}{sup +} and H{sup +} at Val Gerola, where the damage symptoms were more evident. In addition, the canopy leaching of Ca{sup 2+}, K{sup +} and weak organic acids were 47%, 21% and 27% higher at Val Gerola than at Val Masino. Annual SO{sub 4}{sup 2-} deposition fluxes (21.3kg ha{sup -1}yr{sup -1} at Val Masino and 23.6kgha{sup -1}yr{sup -1} at Val Gerola) were similar to those reported for moderately polluted European and U.S. sites. Annual N loads were 13.6 and 13.1kgha{sup -1}yr{sup -1} in the bulk input, and 15.0 and 18.0kgha{sup -1}yr{sup -1} in throughfall inputs, at Val Masino and Val Gerola, respectively. The contribution of the organic fraction to the total N atmospheric deposition load is significant, constituting 17% of the bulk flux and 40% of the throughfall flux. Measured nitrogen loads exceed the critical nutrient loads by several kgNha{sup -1} at both stations. In particular the nitrogen throughfall load at Val Gerola was about 3 times higher than the critical values. (author)

  13. Age of uranium ores at Ranger and Jabiluka unconformity vein deposits, Northern Territory, Australia

    International Nuclear Information System (INIS)

    Ludwig, K.R.; Grauch, R.I.; Nutt, C.J.; Frishman, D.; Nash, J.T.; Simmons, K.R.

    1985-01-01

    The Ranger and Jabiluka uranium deposits are the largest in the Alligator Rivers Uranium Field (ARUF), which contains at least 20% of the world's low-cost uranium reserves. Ore occurs in early Proterozoic metasediments, below an unconformity with sandstones of the 1.65 Ga Kombolgie Formation. This study uses U-Pb isotope data from over 60 whole-rock drill core samples that contained a variety of mineral assemblages and textures. Data for Ranger samples indicate a well-defined age of 1.74 +/-.02 Ga. This 1.74 Ga age is distinctly pre-Kombolgie, so the Ranger deposit cannot have been formed by processes requiring its presence. This Ranger age is consistent, however, with mineralization related to heating associated with either the emplacement of early post-metamorphic granites, or possibly with intrusion of the nearby Oenpelli Dolerite. In contrast, data for the least-altered Jabiluka ores yield a concordia-intercept age of 1.44 +/-.02 Ga--significantly younger than the Ranger age, and also younger than the Komobolgie. This age may correspond to a regional thermal event, as indicated both by mafic dikes of roughly this age and a zircon lower-intercept age from a nearby granite-gneiss. Thus, together with the well-defined ∼900 Ma age of ores at the Nabarlek deposit, there are at least 3 distinct periods of major U-mineralization in the ARUF. Data for both Ranger and Jabiluka indicate the same, profound isotopic disturbance at some time in the interval of 0.4-0.6 Ga. Possibly this time corresponds to the development of basins and associated basalt flows to the W and SW, a suggested by Crick et. al. (1980)

  14. High-Resolution Subsurface Imaging and Stratigraphy of Quaternary Deposits, Marapanim Estuary, Northern Brazil

    Science.gov (United States)

    Silva, C. A.; Souza Filho, P. M.; Gouvea Luiz, J.

    2007-05-01

    The Marapanim estuary is situated in the Para Coastal Plain, North Brazil. It is characterized by an embayed coastline developed on Neogene and Quaternary sediments of the Barreiras and Pos-Barreiras Group. This system is strongly influenced by macrotidal regimes with semidiurnal tides and by humid tropical climate conditions. The interpretation of GPR-reflections presented in this paper is based on correlation of the GPR signal with stratigraphic data acquired on the coastal plain through five cores that were taken along GPR survey lines from the recent deposits and outcrops observed along to the coastal area. The profiles were obtained using a Geophysical Survey Systems Inc., Model YR-2 GPR, with monostatic 700 MHz antenna that permitted to get records of subsurface deposits at 20m depth. Were collected 54 radar sections completing a total of 4.360m. The field data were analyzed using a RADAN software and applying different filters. The interpretation of radar facies following the principles of seismic stratigraphy that permitted analyze the sedimentary facies and facies architecture in order to understand the lithology, depositional environments and stratigraphic evolution of this sedimentary succession as well as to leading to a more precise stratigraphic framework for the Neogene to Quaternary deposits at Marapanim coastal plain. Facies characteristics and sedimentologic analysis (i.e., texture, composition and structure aspects) were investigated from five cores collected through a Rammkernsonde system. The locations were determined using a Global Positioning System. Remote sensing images (Landsat-7 ETM+ and RADARSAT-1 Wide) and SRTM elevation data were used to identify and define the distribution of the different morphologic units. The Coastal Plain extends west-east of the mouth of the Marapanim River, where were identified six morphologic units: paleodune, strand plain, recent coastal dune, macrotidal sandy beach, mangrove and salt marsh. The integration

  15. Controls of tectonics and sediment source locations on along-strike variations in transgressive deposits on the northern California margin

    Science.gov (United States)

    Spinelli, G.A.; Field, M.E.

    2003-01-01

    We identify two surfaces in the shallow subsurface on the Eel River margin offshore northern California, a lowstand erosion surface, likely formed during the last glacial maximum, and an overlying surface likely formed during the most recent transgression of the shoreline. The lowstand erosion surface, which extends from the inner shelf to near the shelfbreak and from the Eel River to Trinidad Head (???80 km), truncates underlying strata on the shelf. Above the surface, inferred transgressive coastal and estuarine sedimentary units separate it from the transgressive surface on the shelf. Early in the transgression, Eel River sediment was likely both transported down the Eel Canyon and dispersed on the slope, allowing transgressive coastal sediment from the smaller Mad River to accumulate in a recognizable deposit on the shelf. The location of coastal Mad River sediment accumulation was controlled by the location of the paleo-Mad River. Throughout the remainder of the transgression, dispersed sediment from the Eel River accumulated an average of 20 m of onlapping shelf deposits. The distribution and thickness of these transgressive marine units was strongly modified by northwest-southeast trending folds. Thick sediment packages accumulated over structural lows in the lowstand surface. The thinnest sediment accumulations (0-10 m) were deposited over structural highs along faults and uplifting anticlines. The Eel margin, an active margin with steep, high sediment-load streams, has developed a thick transgressive systems tract. On this margin sediment accumulates as rapidly as the processes of uplift and downwarp locally create and destroy accommodation space. Sequence stratigraphic models of tectonically active margins should account for variations in accommodation space along margins as well as across them. ?? 2003 Elsevier Science B.V. All rights reserved.

  16. Air pollution in northern Sweden. Deposition, levels and effects Oct 1994 - Sep 1995; Luftfoeroreningar i norra Sverige. Nedfall, halter och effekter oktober 1994 - september 1995

    Energy Technology Data Exchange (ETDEWEB)

    Hallgren-Larsson, E; Sjoeberg, K; Westling, O

    1996-06-01

    The purpose of the monitoring programme is to quantify sulphur and nitrogen deposition to forests, and to illustrate possible acidification of the soil. Deposition is investigated by precipitation studies in open field areas and as throughfall. Soil water chemistry in the forest stands is used as indicator of soil conditions. Air concentrations of sulphur dioxide, nitrogen dioxide, and ammonia were measured at two sites in the county of Jaemtland. This report concerns the hydrological year from October 1994 through September 1995 for 17 locations in the four most northern counties of Sweden. The results are compared with previous years and other regions in Sweden. The results shows a gradient with more precipitation, higher concentrations and larger deposition of sulphur and nitrogen at coastal than at inland locations. Mean from all 17 locations were pH 4.8 and sulphur concentration 0.4 mg/l (SO{sub 4}-S{sub ex}). Concentrations of nitrogen as nitrate and as ammonium were about 0.2 mg/l each. About half of the locations received larger amounts than target loads set for northern Sweden. Deposition of sulphur decreased in the county of Norrbotten during the last 4 years. Greater loads of sulphur and nitrogen were deposited in southern than in northern Sweden. The most acidified soil solutions (pH 4.5-4.6) with highest concentrations of aluminium were found at coastal locations outside Luleaa and Umeaa. At many locations in southern Sweden acidified soil solutions, rich in aluminium and poor in base cations, were detected. Similar conditions were found at two coastal locations in northern Sweden. Highest air concentrations of sulphur dioxide were found during January 1995. Nitrogen dioxide concentrations were highest during November 1994 through March 1995. A gradient of air concentrations of sulphur dioxide was found, with decreasing concentrations from southern to northern Sweden. 15 refs, 57 figs, 11 tabs

  17. NKS NordRisk II: Atlas of long-range atmospheric dispersion and deposition of radionuclides from selected risk sites in the Northern Hemisphere

    International Nuclear Information System (INIS)

    Smith Korsholm, U.; Havskov Soerensen, J.; Astrup, P.; Lauritzen, B.

    2011-04-01

    The present atlas has been developed within the NKS/NordRisk-II project 'Nuclear risk from atmospheric dispersion in Northern Europe'. The atlas describes risks from hypothetical long-range dispersion and deposition of radionuclides from 16 nuclear risk sites on the Northern Hemisphere. The atmospheric dispersion model calculations cover a period of 30 days following each release to ensure almost complete deposition of the dispersed material. The atlas contains maps showing the total deposition and time-integrated air concentration of Cs-137 and I-131 based on three years of meteorological data spanning the climate variability associated with the North Atlantic Oscillation, and corresponding time evolution of the ensemble mean atmospheric dispersion. (Author)

  18. NKS NordRisk II: Atlas of long-range atmospheric dispersion and deposition of radionuclides from selected risk sites in the Northern Hemisphere

    Energy Technology Data Exchange (ETDEWEB)

    Smith Korsholm, U.; Havskov Soerensen, J. (Danish Meteorological Institute (DMI), Copenhagen (Denmark)); Astrup, P.; Lauritzen, B. (Technical Univ. of Denmark, Risoe National Lab. for Sustainable Energy. Radiation Research Div., Roskilde (Denmark))

    2011-04-15

    The present atlas has been developed within the NKS/NordRisk-II project 'Nuclear risk from atmospheric dispersion in Northern Europe'. The atlas describes risks from hypothetical long-range dispersion and deposition of radionuclides from 16 nuclear risk sites on the Northern Hemisphere. The atmospheric dispersion model calculations cover a period of 30 days following each release to ensure almost complete deposition of the dispersed material. The atlas contains maps showing the total deposition and time-integrated air concentration of Cs-137 and I-131 based on three years of meteorological data spanning the climate variability associated with the North Atlantic Oscillation, and corresponding time evolution of the ensemble mean atmospheric dispersion. (Author)

  19. Fluvial depositional environment evolving into deltaic setting with marine influences in the buntsandstein of northern vosges (France)

    Science.gov (United States)

    Gall, Jean-Claude

    The Buntsandstein in the Northern Vosges (France) originates mainly in an inland braidplain fluvial environment which passes in the upper part of the sequence into deltaic milieu in the coastal plain along the border of the sea, with the continental environment finally being drowned with the transgression of the shallow sea. The fluvial sedimentation is characterized by the presence of two facies throughout the Buntsandstein : channel facies and overbank plain facies. The channel facies comprises sandy and conglomeratic deposits forming within active streams by strong currents, whereas the overbank plain facies is built up of silty-clayey sandstones or silt/clay originating in stagnant water in abandoned watercourses, ponds, pools and puddles. The significance of particularly the floodplain sediments is subjected to considerable changes throughout the Buntsandstein sequence. There are all stages of transition between overbank plain deposits being only preserved in ghost-like facies as reworked clasts due to effective secondary removal of primarily occasionally formed suspension fines, and an abundance of autochthonous floodplain sediments in the depositional record resulting from favourable conditions of primary origin and secondary preservation. Reworked ventifacts within fluvial channel sediments testify to subordinate aeolian influences in the alluvial plain, with reasonable reworking, however, having removed all in situ traces of wind activity. Declining aridity of palaeoclimate towards the top is indicated by the appearance of violet horizon palaeosols in the Zone-Limite-Violette and the Couches intermédiaires being accompanied by Bröckelbank carbonate breccias originating from concentration of reworked fragments of pedogenic carbonate nodules. Biogenic traces are in the lower part of the sequence mainly present as Planolites burrows in the finer-grained sediments. Palaeosalinities as revealed from boron contents indicate progressively increasing

  20. Discussion on the petrochemistry characteristics and uranium deposit of Xiazhuang pluton in northern Guangdong province

    International Nuclear Information System (INIS)

    Wu Jiguang

    2011-01-01

    The element characteristic of Indo-Chinese epoch Xiazhuang granite is rich in silicon (SiO 2 =69.13%∼73.39%), alkalis (K 2 O+Na 2 O=7.49%∼8.69%), the ASI=1.01∼1.21 and ratio of w (K 2 O)/w (Na 2 O)>1, Xiazhuang pluton is belong to high potassium calcium-alkaline and aluminous series rocks. It shows that the pluton is typical S-type granite, little part is A-type granite character. Under the extension tectonic setting of lithosphere, the Xiazhuang pluton is partial melting product that making up metamorphic mud and sandstone together. By analysing the tectonic setting,the pluton is belong to post-collision granite that original rock provide abundant of uranium content for granite and the tectonic setting of forming provide the moving channels and occurrence space for uranium deposit. (authors)

  1. 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

    Directory of Open Access Journals (Sweden)

    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

  2. Optical dating of eolian deposits since the last interglacial along the northern margin of the Chinese Loess Plateau

    Science.gov (United States)

    Lü, Tongyan; Sun, Jimin; Gong, Zhijun

    2018-04-01

    Understanding the chronology of eolian sand-loess-paleosol sequences along the northern margin of the Chinese Loess Plateau (CLP) is crucial for comprehending climate change and the advance and retreat of the adjacent Mu Us desert. In this study, a sand-loess-soil sequence from the northern margin of the CLP was studied by applying the single aliquot regenerative (SAR) protocol to quartz grains, and the multi-elevated-temperature post-IR IRSL (MET-pIRIR) protocol to K-feldspar grains. For equivalent dose (De) determination, 63-90 μm quartz and K-feldspar grains were used. Our results indicate that the MET-pIRIR ages of K-feldspar grains in this sequence range from 94.4 ± 7.0 ka to 148.3 ± 13.3 ka for the last interglacial paleosol (S1); for the upper part of the section, quartz-based SAR-OSL dating was used, yielding ages spanning from 5.8 ± 0.4 ka to 35.9 ± 4.1 ka. After cross-checking these results with previously-reported isochron OSL and TL ages, the reliability of the MET-pIRIR protocol when applied to the last interglacial paleosol was confirmed. Based on a new OSL chronology of the Shimao profile, the studied eolian deposits can be broadly correlated with the last glacial-interglacial cycle, but their dating also points to sedimentary hiatuses occurring at 94.4 ka, 35.9 ka and 5.8 ka, due most probably to strong wind erosion caused by intensified cold-dry winter monsoonal circulations during the last glacial maxima.

  3. 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

  4. 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.

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

    Science.gov (United States)

    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.

  6. Hydrogeologic field study of the Koongarra uranium deposit in the Northern Territory of Australia

    International Nuclear Information System (INIS)

    Marley, R.D.

    1990-01-01

    This study is focused on the hydrogeologic characterization of the more southwesterly of the two Koongarra orebodies. The general objective is to augment the current hydrogeologic understanding of groundwater flow so that realistic transport models can be developed. Water level, aquifer tests, and slug-test data indicate that the Koongarra uranium deposit is within a low permeability, semi-confined, fractured-schist aquifer. Water levels demonstrate semi-diurnal and diurnal fluctuations related to earth tides and evapotranspiration stresses. Hydraulic test data were analyzed with homogenous isotropic and homogenous anisotropic models which allowed parameter estimation for sub-regions of the study area. Dominant anisotropy is subparallel to lithologic layering and the reverse fault. Slug tests reveal regions controlled by low storage but highly conductive fractures and isolated regions of low conductivity. Hydraulic connection of the weathered zone with the underlying schist is dependent on clay content and fractures. Environmental isotopes indicate ground water has been isolated from the atmosphere for a least 40 years and possibly several thousand years in some locations. Water budget calculations indicate the majority of recharge must be from direct infiltration through the weathered profile to account for the calculated ground-water fluxes. 36 refs., 12 tabs., 52 figs

  7. 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 » Tourism in Chile Tourism in Chile Map of

  8. Characterization of Particulate Matter Profiling and Alveolar Deposition from Biomass Burning in Northern Thailand: The 7-SEAS Study

    Science.gov (United States)

    Chuang, Hsiao-Chi; Hsiao, Ta-Chih; Wang, Sheng-Hsiang; Tsay, Si-Chee; Lin, Neng-Huei

    2016-01-01

    Biomass burning (BB) frequently occurs in SouthEast Asia (SEA), which significantly affects the air quality and could consequently lead to adverse health effects. The aim of this study was to characterize particulate matter (PM) and black carbon (BC) emitted from BB source regions in SEA and their potential of deposition in the alveolar region of human lungs. A 31-day characterization of PM profiling was conducted at the Doi Ang Khang (DAK) meteorology station in northern Thailand in March 2013. Substantial numbers of PM (10147 +/- 5800 # per cubic centimeter) with a geometric mean diameter (GMD) of 114.4 +/- 9.2 nm were found at the study site. The PM of less than 2.5 micron in aerodynamic diameter (PM sub 2.5) hourly-average mass concentration was 78.0 +/- 34.5 per cubic microgram whereas the black carbon (BC) mass concentration was 4.4 +/- 2.6 micrograms per cubic meter. Notably, high concentrations of nanoparticle surface area (100.5 +/- 54.6 square micrometers per cubic centimeter) emitted from biomass burning can be inhaled into the human alveolar region. Significant correlations with fire counts within different ranges around DAK were found for particle number, the surface area concentration of alveolar deposition, and BC. In conclusion, biomass burning is an important PM source in SEA, particularly nanoparticles, which has high potency to be inhaled into the lung environment and interact with alveolar cells, leading to adverse respiratory effects. The fire counts within 100 to 150 km shows the highest Pearson's r for particle number and surface area concentration. It suggests 12 to 24 hr could be a fair time scale for initial aging process of BB aerosols. Importantly, the people lives in this region could have higher risk for PM exposure.

  9. Fluid evolution and ore genesis of the Dalingshang deposit, Dahutang W-Cu ore field, northern Jiangxi Province, South China

    Science.gov (United States)

    Peng, Ning-Jun; Jiang, Shao-Yong; Xiong, Suo-Fei; Pi, Dao-Hui

    2018-02-01

    The Dalingshang W-Cu deposit is located in the North section of the Dahutang ore field, northern Jiangxi Province, South China. Vein- and breccia-style tungsten-copper mineralization is genetically associated with Mesozoic S-type granitic rocks. Infrared and conventional microthermometric studies of both gangue and ore minerals show that the homogenization temperatures for primary fluid inclusions in wolframite ( 340 °C) are similar to those in scheelite ( 330 °C), but about 40 °C higher than those of apatite ( 300 °C) and generally 70 °C higher than those in coexisting quartz ( 270 °C). Laser Raman analysis identifies CH4 and N2 without CO2 in fluid inclusions in scheelite and coexisting quartz, while fluid inclusions in quartz of the sulfide stage have variable CO2 content. The ore-forming fluids overall are characterized by high- to medium-temperature, low-salinity, CH4, N2, and/or CO2-bearing aqueous fluids. Chalcopyrite, muscovite, and sphalerite are the most abundant solids recognized in fluid inclusions from different ores. The H-O-S-Pb isotope compositions favor a dominantly magmatic origin for ores and fluids, while some depleted δ34S values (- 14.4 to - 0.9‰) of sulfides from the sulfide stage are most likely produced by an increase of oxygen fugacity, possibly caused by inflow of oxidized meteoric waters. The microthermometric data also indicate that a simple cooling process formed early scheelite and wolframite. However, increasing involvement of meteoric waters and fluid mixing may trigger a successive deposition of base metal sulfides. Fluid-rock interaction was critical for scheelite mineralization as indicated by in-situ LA-ICP-MS analysis of trace elements in scheelite.

  10. Leaf area and foliar biomass relationships in northern hardwood forests located along an 800 km acid deposition gradient

    International Nuclear Information System (INIS)

    Burton, A.J.; Pregitzer, K.S.; Reed, D.D.

    1991-01-01

    The canopies of northern hardwood forests dominated by sugar maple (Acer saccharum Marsh.) were examined at five locations spanning 800 km along an acid deposition and climatic gradient in the Great Lakes region. Leaf area index (LAI) calculated from litterfall ranged from 6.0 to 8.0 in 1988, from 4.9 to 7.9 in 1989, and from 5.3 to 7.8 in 1990. The data suggest that maximum LAI for the sites is between 7 and 8. Insect defoliation and the allocation of assimilates to reproductive parts in large seed years reduced LAI by up to 34%. Allometric equations for leaf area and foliar biomass were not significantly different among sites. They predicted higher LAI values than were estimated from litterfall and could not account for the influences of defoliation and seed production. Canopy transmittance was a viable alternative for estimating LAI. Extinction coefficients (K) of 0.49 to 0.65 were appropriate for solar elevations of 63 degree to 41 degree. Patterns of specific leaf area (SLA) were similar for the sites. Average sugar maple SLA increased from 147 cm 2 g -1 in the upper 5 m of the canopy to 389 cm 2 g -1 in the seeding layer. Litterfall SLA averaged 196 cm 2 g -1 for all species and 192 cm 2 g -1 for sugar maple. Similarity among the sites in allometric relationships, maximum LAI, canopy transmittance, and patterns of SLA suggests these characteristics were controlled primarily by the similar nutrient and moisture availability at the sites. A general increasing trend in litter production along the gradient could not be attributed to N deposition or length of growing season due to year to year variability resulting from insect defoliation and seed production

  11. Influence of Late Paleozoic Gondwana glaciations on the depositional evolution of the northern Pangean shelf, North Greenland, Svalbard and the Barents Sea

    DEFF Research Database (Denmark)

    Stemmerik, Lars

    2008-01-01

    Outcrop and subsurface data from the central northern margin of the Pangean shelf in North Greenland, Svalbard, and the Norwegian Barents Sea record the depositional response of a Northern Hemisphere subtropical shelf to Late Carboniferous-Early Permian (Bashkirian-Sakmarian) Gondwana glaciations....... The dominant motif is that of meters to tens of meters of exposure-capped cycles of carbonates, mixed carbonates, and siliciclastics and, in older stratigraphic levels, siliciclastics and gypsum. Halitegypsum-carbonate cycles developed in deeper, isolated basins. Individual cycles of carbonate and mixed...

  12. Thermoluminescence applied to uranium exploration and genesis of the Westmoreland uranium deposits - implications for the Northern Territory

    International Nuclear Information System (INIS)

    Hochman, M.B.M.; Ypma, P.J.M.

    1984-01-01

    The Westmoreland uranium deposits occur on the northern flank of the Murphy Tectonic Ridge in the upper member of the Westmoreland Conglomerate. Uranium mineralisation is spatially associated with the contact of the overlying basaltic Siegal Volcanics and the margins of intrusive dolerite dykes which are geochemically similar to the Siegal Volcanics. Thermoluminescence measurements on 800 samples from within the orebodies and surrounding host rock have indicated that all of the Westmoreland Conglomerate has suffered major radiation damage attributable to at least 10 ppm uranium over 10 9 years. The underlying rhyolitic Mid Proterozoic Cliffdale Volcanics have distinctive TL glow curves indicative of radiation sensitisation caused by high uranium contents. These volcanics are part of the Mid Proterozoic volcanic event known to be enriched in uranium. The Westmoreland Conglomerate has been derived by erosion of the uranium-rich Cliffdale Volcanics and associated Nicholson Granite Complex which makes it likely that the Westmoreland Conglomerate had a high inherent uranium content. It is proposed that this precontained uranium within the Westmoreland Conglomerate was remobilized in a convective cell system possibly triggered by intrusion of dolerite dykes, or by a later rejuvenation of vertical structures which provided an ascending heat flow. Pitchblende was precipitated where suitable reducing conditions existed close to the basic volcanics and dykes

  13. Depositional environments, provenance and paleoclimatic implications of Ordovician siliciclastic rocks of the Thango Formation, Spiti Valley, Tethys Himalaya, northern India

    Science.gov (United States)

    Rashid, Shaik A.; Ganai, Javid A.

    2018-05-01

    Recently published findings indicate that the Ordovician period has been much more dynamic than previously anticipated thus making this period significant in geological time. The Ordovician of India can best be studied in the Spiti region because the Spiti basin records the complete uninterrupted history of excellent marine sedimentary rocks starting from Cambrian to Paleogene which were deposited along the northern margin of India. Due to these reasons the geochemical data on the Ordovician rocks from the Spiti region is uncommon. The present geochemical study on the Ordovician Thango Formation (Sanugba Group) is mainly aimed to understand the provenance and the paleoclimatic conditions. The sandstones are the dominant lithology of the Thango Formation with intercalations of minor amount of shales. Detailed petrographic and sedimentological analysis of these rocks suggest that three major depositional environments, viz., fluvial, transitional and marine prevailed in the basin representing transgressive and regressive phases. The major and trace element ratios such as SiO2/Al2O3, K2O/Na2O and La-Th- Sc discrimination diagram suggest that these rocks were deposited in passive margin tectonic settings. Various geochemical discriminants and elemental ratios such as K2O/Na2O, Al2O3/TiO2, La/Sc, Th/Sc, Cr/Th, Zr/Sc, (Gd/Yb)N and pronounced negative Eu anomalies indicate the rocks to be the product of weathering of post-Archean granites. The striking similarities of the multi-elemental spider diagrams of the studied sediments and the Himalayan granitoids indicate that sediments are sourced from the Proterozoic orogenic belts of the Himalayan region. Chemical index of alteration (CIA) values of the studied sediments (55-72) suggest that the source rocks underwent low to moderate degree of chemical weathering. The span of the CIA values (55-72) recorded in the sediments from the Spiti region may have resulted from varying degrees of weathering conditions in the source area

  14. Evolution of magmatism from the uppermost cretaceous to Oligocene, and its relationship to changing tectonic regime, in the Inca de Oro-El Salvador area (Northern Chile)

    International Nuclear Information System (INIS)

    Cornejo, Paula; Matthews, Stephen

    2001-01-01

    We present geochronological and petrological data for extrusive and intrusive rocks in the Inca de Oro and El Salvador sheets (in prep.), and the Potrerillos (Tomlinson et al., 1999) and Salar de Maricunga sheets (Cornejo et al., 1998), III Region, Chile (26 o -27 o S). Most of these data were collected as part of the SERNAGEOMIN regional mapping programme. Additionally, we include published data for El Salvador and Potrerillos districts (Cornejo et al., 1997; Marsh et al., 1997; Gustafson et al., 2001). The dataset includes K/Ar, Ar/Ar and U-Pb mineral ages, which have been carefully selected for quality. The area is underlain by Carboniferous-Permian granitic basement rocks, which are covered by Triassic to Early Upper Cretaceous volcanic and sedimentary successions, including both marine and continental sequences (Cornejo et al., 1993). The period studied in this paper includes extrusive and intrusive rocks of Maastrichtian to Oligocene age, which are of particular interest since they record the 'preparation' of the lithosphere prior to, during, and after the mid-Eocene Incaic deformation and associated porphyry copper event. Shortening in the early-upper Cretaceous (95-85Ma; e.g. Mpodozis and Ramos, 1989; Arevalo and Grocott, 2000) deformed large areas of northen Chile, and marked the transition from the dominance of intra-arc extension to that of shortening punctuated by periods of extension. We recognise seven tectono-magmatic periods from the uppermost Cretaceous to Oligocene, comprising a volcanic sedimentary event contemporaneous with an extensional tectonic regime in the Upper Cretaceous, associated with graben formation, followed by an important compressive event at the beginning of the Tertiary. The middle Paleocene was again dominated by voluminous volcanic activity (collapse calderas) in an extensional regime. During the lowest Eocene the magmatic activity in the area shows a gradual transition from pyroxene-bearing to amphibole-bearing lithologies

  15. Rapid tectonic and paleogeographic evolution associated with the development of the Chucal anticline and the Chucal-Lauca Basin in the Altiplano of Arica, northern Chile

    Science.gov (United States)

    Charrier, Reynaldo; Chávez, Alvaro N.; Elgueta, Sara; Hérail, Gérard; Flynn, John J.; Croft, Darin A.; Wyss, André R.; Riquelme, Rodrigo; García, Marcelo

    2005-05-01

    The east-vergent Chucal thrust system, on the east side of the Chapiquiña-Belén ridge in the Western Cordillera, was continuously or almost continuously active for ˜18 m.y. (2.7 Ma). Contractional activity deformed late Oligocene tuffaceous, fluvial, or distal alluvial deposits of the uppermost Lupica Formation; fluvial and lacustrine deposits of the Miocene Chucal Formation; tuffaceous and coarse fluvial deposits of the Quebrada Macusa Formation; and the lower part of the westernmost, latest Miocene?—Pliocene, essentially lacustrine Lauca Formation. It controlled the paleogeographic and paleoenvironmental conditions in which these units were deposited. More humid conditions on the east side of the Chapiquiña-Belén ridge favored the development of an abundant mammal fauna and flora. The deformation is characterized by the Jaropilla thrust fault and the Chucal anticline, which is east of the fault. Deformation on the Chucal anticline began before the deposition of the Chucal Formation and was controlled by a blind thrust fault. The west flank has a nearly constant dip (45-50°) to the west and nearly continuous stratigraphic units, whereas on the east flank, the dip angle is variable, diminishing away from the axis, and the stratigraphic units are discontinuous. The anticline growth on this flank caused the development of three observable progressive unconformities. Deformation was particularly rapid during the deposition of the ˜600 m thick Chucal Formation (between the 21.7±0.8 Ma old uppermost Lupica Formation and the 17.5±0.4 Ma old base of the Quebrada Macusa Formation, a 4 m.y. period). The deformation rate decreased during the deposition of both (1) the ˜200 m thick Quebrada Macusa Formation (between the 17.5±0.4 Ma age of its basal deposits and the ˜11 Ma age of its uppermost levels, a 7 m.y. period) and (2) the lower Lauca Formation (between the ˜11 Ma age of the upper Quebrada Macusa Formation and the 2.3±0.7 Ma old Lauca ignimbrite, which

  16. Meat quality attributes of the Longissimus lumborum muscle of the Kh'ara genotype of llama (Lama glama) reared extensively in northern Chile.

    Science.gov (United States)

    Mamani-Linares, L W; Gallo, C B

    2013-05-01

    Twenty male llama of the Kh'ara genotype, reared extensively in the north of Chile, were slaughtered at ages between 2 and 4 permanent teeth (2 to 3.5years) and analyses were carried out on the Longissimus lumborum muscle, including composition (moisture, fat, protein, ash, cholesterol, amino acids, fatty acid profile and collagen content) and meat quality parameters (pH, color, water holding capacity and Warner-Bratzler shear-force). Llama meat was characterized by a low cholesterol (39.04mg/100g) and intramuscular fat (1.56%) content, a total collagen content of 6.28mg/g, of which 20.28% was soluble collagen. Amino acid composition and fatty acid profile were similar to those found for beef finished on forage. Llama meat showed a low n-6/n-3 (4.69) and hypocholesterolemic/hypercholesterolemic (1.55) ratio and acceptable values of DFA (65.78%). Quality parameters in llama Longissimus muscle were within the ranges reported for more traditional meats such as beef and lamb. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Estimation of Arsenic Intake from Drinking Water and Food (Raw and Cooked in a Rural Village of Northern Chile. Urine as a Biomarker of Recent Exposure

    Directory of Open Access Journals (Sweden)

    Oscar Pablo Diaz

    2015-05-01

    Full Text Available The aim of this study was to estimate both the contribution of drinking water and food (raw and cooked to the total (t-As and inorganic (i-As arsenic intake and the exposure of inhabitants of Socaire, a rural village in Chile´s Antofagasta Region, by using urine as biomarker. The i-As intake from food and water was estimated using samples collected between November 2008 and September 2009. A 24-hour dietary recall questionnaire was given to 20 participants. Drinking water, food (raw and cooked and urine samples were collected directly from the homes where the interviewees lived. The percentage of i-As/t-As in the drinking water that contributed to the total intake was variable (26.8–92.9. Cereals and vegetables are the food groups that contain higher concentrations of i-As. All of the participants interviewed exceeded the reference intake FAO/OMS (149.8 µg∙i-As·day−1 by approximately nine times. The concentration of t-As in urine in each individual ranged from 78 to 459 ng·mL−1. Estimated As intake from drinking water and food was not associated with total urinary As concentration. The results show that both drinking water and food substantially contribute to i-As intake and an increased exposure risk to adult residents in contaminated areas.

  18. Estimation of Arsenic Intake from Drinking Water and Food (Raw and Cooked) in a Rural Village of Northern Chile. Urine as a Biomarker of Recent Exposure

    Science.gov (United States)

    Diaz, Oscar Pablo; Arcos, Rafael; Tapia, Yasna; Pastene, Rubén; Velez, Dínoraz; Devesa, Vicenta; Montoro, Rosa; Aguilera, Valeska; Becerra, Miriam

    2015-01-01

    The aim of this study was to estimate both the contribution of drinking water and food (raw and cooked) to the total (t-As) and inorganic (i-As) arsenic intake and the exposure of inhabitants of Socaire, a rural village in Chile´s Antofagasta Region, by using urine as biomarker. The i-As intake from food and water was estimated using samples collected between November 2008 and September 2009. A 24-hour dietary recall questionnaire was given to 20 participants. Drinking water, food (raw and cooked) and urine samples were collected directly from the homes where the interviewees lived. The percentage of i-As/t-As in the drinking water that contributed to the total intake was variable (26.8–92.9). Cereals and vegetables are the food groups that contain higher concentrations of i-As. All of the participants interviewed exceeded the reference intake FAO/OMS (149.8 µg∙i-As·day−1) by approximately nine times. The concentration of t-As in urine in each individual ranged from 78 to 459 ng·mL−1. Estimated As intake from drinking water and food was not associated with total urinary As concentration. The results show that both drinking water and food substantially contribute to i-As intake and an increased exposure risk to adult residents in contaminated areas. PMID:26006131

  19. 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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

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

    2003-09-01

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

  1. 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

  2. ALS-based hummock size-distance relationship assessment of Mt Shasta debris avalanche deposit, Northern California, USA

    Science.gov (United States)

    Tortini, Riccardo; Carn, Simon; van Wyk de Vries, Benjamin

    2015-04-01

    The failure of destabilized volcano flanks is a likely occurrence during the lifetime of a stratovolcano, generating large debris avalanches and drastically changing landforms around volcanoes. The significant hazards associated with these events in the Cascade range were demonstrated, for example, by the collapse of Mt St Helens (WA), which triggered its devastating explosive eruption in 1980. The rapid modification of the landforms due to these events makes it difficult to estimate the magnitude of prehistoric avalanches. However, the widespread preservation of hummocks along the course of rockslide-debris avalanches is highly significant for understanding the physical characteristics of these landslides. Mt Shasta is a 4,317 m high, snow-capped, steep-sloped stratovolcano located in Northern California. The current edifice began forming on the remnants of an ancestral Mt Shasta that collapsed ~300-380k years ago producing one of the largest debris avalanches known on Earth. The debris avalanche deposit (DAD) covers a surface of ~450 km2 across the Shasta valley, with an estimated volume of ~26 km3. We analyze ALS data on hummocks from the prehistoric Shasta valley DAD in northern California (USA) to derive the relationship between hummock size and distance from landslide source, and interpret the geomorphic significance of the intercept and slope coefficients of the observed functional relationships. Given the limited extent of the ALS survey (i.e. 40 km2), the high-resolution dataset is used for validation of the morphological parameters extracted from freely available, broader coverage DTMs such as the National Elevation Dataset (NED). The ALS dataset also permits the identification of subtle topographic features not apparent in the field or in coarser resolution datasets, including a previously unmapped fault, of crucial importance for both seismic and volcanic hazard assessment in volcanic areas. We present evidence from the Shasta DAD of neotectonic

  3. 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

  4. Low-pressure evolution of arc magmas in thickened crust: The San Pedro-Linzor volcanic chain, Central Andes, Northern Chile

    Science.gov (United States)

    Godoy, Benigno; Wörner, Gerhard; Kojima, Shoji; Aguilera, Felipe; Simon, Klaus; Hartmann, Gerald

    2014-07-01

    Magmatism at Andean Central Volcanic Zone (CVZ), or Central Andes, is strongly influenced by differentiation and assimilation at high pressures that occurred at lower levels of the thick continental crust. This is typically shown by high light to heavy rare earth element ratios (LREE/HREE) of the erupted lavas at this volcanic zone. Increase of these ratios with time is interpreted as a change to magma evolution in the presence of garnet during evolution of Central Andes. Such geochemical signals could be introduced into the magmas be high-pressure fractionation with garnet on the liquidus and/or assimilation from crustal rocks with a garnet-bearing residue. However, lavas erupted at San Pedro-Linzor volcanic chain show no evidence of garnet fractionation in their trace element patterns. This volcanic chain is located in the active volcanic arc, between 22°00‧S and 22°30‧S, over a continental crust ˜70 km thick. Sampled lavas show Sr/Y and Sm/Yb ratios Chile. We relate our geochemical observations to shallow crustal evolution of primitive magmas involving a high degree of assimilation of upper continental crust. We emphasize that low pressure AFC- (Assimilation Fractional Crystallization) type evolution of the San Pedro-Linzor volcanic chain reflects storage, fractionation, and contamination of mantle-derived magmas at the upper felsic crust (<40 km depth). The ascent of mantle-derived magmas to mid-crustal levels is related with the extensional regime that has existed in this zone of arc-front offset since Late-Miocene age, and the relatively thin portion of mafic lower crust observed below the volcanic chain.

  5. True Volumes of Slope Failure Estimated From a Quaternary Mass-Transport Deposit in the Northern South China Sea

    Science.gov (United States)

    Sun, Qiliang; Alves, Tiago M.; Lu, Xiangyang; Chen, Chuanxu; Xie, Xinong

    2018-03-01

    Submarine slope failure can mobilize large amounts of seafloor sediment, as shown in varied offshore locations around the world. Submarine landslide volumes are usually estimated by mapping their tops and bases on seismic data. However, two essential components of the total volume of failed sediments are overlooked in most estimates: (a) the volume of subseismic turbidites generated during slope failure and (b) the volume of shear compaction occurring during the emplacement of failed sediment. In this study, the true volume of a large submarine landslide in the northern South China Sea is estimated using seismic, multibeam bathymetry and Ocean Drilling Program/Integrated Ocean Drilling Program well data. The submarine landslide was evacuated on the continental slope and deposited in an ocean basin connected to the slope through a narrow moat. This particular character of the sea floor provides an opportunity to estimate the amount of strata remobilized by slope instability. The imaged volume of the studied landslide is 1035 ± 64 km3, 406 ± 28 km3 on the slope and 629 ± 36 km3 in the ocean basin. The volume of subseismic turbidites is 86 km3 (median value), and the volume of shear compaction is 100 km3, which are 8.6% and 9.7% of the landslide volume imaged on seismic data, respectively. This study highlights that the original volume of the failed sediments is significantly larger than that estimated using seismic and bathymetric data. Volume loss related to the generation of landslide-related turbidites and shear compaction must be considered when estimating the total volume of failed strata in the submarine realm.

  6. Natural and anthropogenic influences on depositional architecture of the Ural Delta, Kazakhstan, northern Caspian Sea, during the past 70 years

    Science.gov (United States)

    Scarelli, Frederico M.; Cantelli, Luigi; Barboza, Eduardo G.; Gabbianelli, Giovanni

    2017-05-01

    This paper focuses on the Ural Delta in the northern zone of the Caspian Sea, an area with particular characteristics, where intense influence from anthropogenic and natural factors exists, which acts on the fragile delta system. We built a database to integrate the data from the published sources, bathymetric survey, and recent images in the geographical information system (GIS) environment. The results were linked to the Caspian Sea level (CSL) curve, which had many variations, changing the Ural Delta system's dynamics and in its architecture. In addition, the anthropogenic changes contribute to shaping the actual Ural Delta architecture. Through the link between the results and CSL, we reconstructed an evolution model for the Ural Delta system for the last century and identified three different architectures for the Ural Delta, determined by the energy that acted on the system in the last century and by the anthropogenic changes. This work identifies six different delta phases, which are shaped by CSL changes during the last 70 years and by anthropogenic changes. The delta phases recognized are: i) a Lobate Delta phase, shaped during high CSL before 1935; ii) Natural Elongate Delta 1935-1950 formed during rapid CSL fall; iii) Anthropogenic Elongate Delta 1950-1966, formed during rapid CSL fall and after the Ural-Caspian Sea canal construction, which modified the sedimentary deposition on the delta; iv) Anthropogenic Elongate Delta 1966-1982 shaped during low CSL phase; v) Anthropogenic Elongate Delta 1982-1996 formed during a rapid CSL rise phase; and vi) Anthropogenic Elongate Delta 1996-2009 shaped during high CSL that represent the last phase and actual Ural Delta architecture.

  7. Heavy metals in soils and sedimentary deposits of the Padanian Plain (Ferrara, Northern Italy). Characterisation and biomonitoring

    Energy Technology Data Exchange (ETDEWEB)

    Bianchini, Gianluca; Natali, Claudio [Ferrara Univ. (Italy). Dept. of Earth Sciences; C.N.R, Pisa (Italy). Ist. di Geoscienze e Georisorse; Di Giuseppe, Dario; Beccaluva, Luigi [Ferrara Univ. (Italy). Dept. of Earth Sciences

    2012-08-15

    Purpose: This contribution investigates agricultural soils and sedimentary deposits in the province of Ferrara (Padanian alluvial plain, Northern Italy) in order to: examine their genesis; to define the geochemical background of the area; and to evaluate the existence of anthropogenic contamination. Moreover, environmental risk related to the presence of potentially toxic heavy metals that can be transferred into agricultural products (and consequently bio-accumulated in the food chain) was also assessed. Materials and methods: The analyses (reported in an extensive supplementary dataset) include XRD, XRF and ICP-MS assessment of bulk sediments, tests of metal extraction with aqua regia, as well as analyses of local agricultural products, i.e. biomonitoring which is important in the evaluation of element mobility. Results and discussion: Based on the results, GIS-based geochemical maps were produced and local background levels were defined. This approach demonstrated that high concentrations of Cr and Ni is a natural (geogenic) feature of the local alluvial terrains, which in turn is related to the origin and provenance of the sediments, as confirmed by the lack of top enrichment in all of the investigated sites. Tests of metal extraction and analyses of agricultural products provide guidelines for agricultural activities, suggesting that extensive use of sewage sludge, industrial slurry and manure (that are often rich in metals) should be minimised. Conclusions: The dataset reported in this paper shows that the agricultural terrains of the studied alluvial plain are not characterised by anthropogenic heavy metal pollution. In spite of the elevated natural background of Cr and Ni, most of the local agricultural products do not show significant evidence of bio-magnification. Exceptions are represented by forage grass (alfalfa) and corn (maize) that tend to uptake As and Ni, respectively. This demonstrates that in agricultural areas, a geochemical risk assessment

  8. Source of boron in the Palokas gold deposit, northern Finland: evidence from boron isotopes and major element composition of tourmaline

    Science.gov (United States)

    Ranta, Jukka-Pekka; Hanski, Eero; Cook, Nick; Lahaye, Yann

    2017-06-01

    The recently discovered Palokas gold deposit is part of the larger Rompas-Rajapalot gold-mineralized system located in the Paleoproterozoic Peräpohja Belt, northern Finland. Tourmaline is an important gangue mineral in the Palokas gold mineralization. It occurs as tourmalinite veins and as tourmaline crystals in sulfide-rich metasomatized gold-bearing rocks. In order to understand the origin of tourmaline in the gold-mineralized rocks, we have investigated the major element chemistry and boron isotope composition of tourmaline from three areas: (1) the Palokas gold mineralization, (2) a pegmatitic tourmaline granite, and (3) the evaporitic Petäjäskoski Formation. Based on textural evidence, tourmaline in gold mineralization is divided into two different types. Type 1 is located within the host rock and is cut by rock-forming anthophyllite crystals. Type 2 occurs in late veins and/or breccia zones consisting of approximately 80% tourmaline and 20% sulfides, commonly adjacent to quartz veins. All the studied tourmaline samples belong to the alkali-group tourmaline and can be classified as dravite and schorl. The δ11B values of the three localities lie in the same range, from 0 to -4‰. Tourmaline from the Au mineralization and from the Petäjäskoski Formation has similar compositional trends. Mg is the major substituent for Al; inferred low Fe3+/Fe2+ ratios and Na values (molybdenite related to the tourmaline-sulfide-quartz veins, we propose that the tourmaline-forming process is a result of a single magmatic-hydrothermal event related to the extensive granite magmatism at around 1.79-1.77 Ga. Tourmaline was crystallized throughout the hydrothermal process, which resulted in the paragenetic variation between type 1 and type 2. The close association of tourmaline and gold suggests that the gold precipitated from the same boron-rich source as tourmaline.

  9. High-resolution, multi-proxy characterization of the event deposit generated by the catastrophic events associated with the Mw 6.2 earthquake of 21 April 2007 in Aysén fjord (Chile)

    Science.gov (United States)

    De Batist, M. A.; Van Daele, M. E.; Cnudde, V.; Duyck, P.; Tjallingii, R. H.; Pino, M.; Urrutia, R.

    2012-12-01

    In 2007, a seismic swarm with more than 7000 recorded earthquakes affected the region around Aysén fjord, Chile (45°25'S). The series of seismic events reached a maximum on 21 April 2007, with an Mw 6.2 earthquake. Intensities as high as VIII to IX on the Modified Mercalli scale were reported around the epicenter. Multiple debris flows, rock slides and rock avalanches were triggered along the fjord's coastline, and several of these caused impact waves or tsunamis with wave heights of up to 6 m, which inundated the fjord shorelines and caused heavy damage and 10 casualties. In order to characterize in detail the imprint left by this series of catastrophic events in the sedimentary record of the fjord, we conducted a multi-disciplinary survey of the inner fjord region in December 2009. Multibeam bathymetry and high-resolution reflection seismic data reveal that large parts of the fjord basin floor, mostly at the foot of the fjord's steep underwater slopes, are covered by recent mass-wasting deposits or consist of mass-wasting-induced deformed basin-plain sediments. A series of short sediment cores collected throughout the inner fjord contain also the more distal deposits of this significant basin-wide mass-wasting event. By combining classical sedimentological techniques (i.e. grain-size analysis, LOI and magnetic susceptibility measurements, all at high resolution) with X-ray CT scanning and XRF scanning we were able to demonstrate that the event deposits encountered in the cores have a very complex signature and actually consist of a succession of several sub-deposits, comprising distal mass-flow deposits from different source areas (as evidenced by XRF-derived geochemical provenance indications) and with a different flow direction (as evidenced by CT-derived 3D flow-direction indications, such as imbricated rip-up mud clasts, cross and convolute laminations) and tsunami- or seiche-generated deposits. This allowed us to reconstruct the succession of sedimentary

  10. 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

    that of the Neotropics and other South American countries. There are 21 tribes of Carabidae represented in Chile (38.8 % of the total found in Neotropics, with 95 genera (28.2 % of the Neotropical fauna, and 365 species (7.9 % of the total from the Neotropics. Chile has a low number of tribes compared with other countries, but it is an important area because six relictual tribes occur within it, being mostly gondwanan or pangeic. At the generic level, 18 genera are endemic (18.5 % of Chilean genera, 28 genera are restricted to Chile and Argentina, and six to Chile, Argentina, and Uruguay. The number of carabid species in Chile is low compared with other South American countries, but the number of endemic species is high, 204, which is 55.8 % of the total carabid fauna of the country. This high endemicity in Chile might be due to Chile´s isolated situation in South America. The Andean mountains and the Northern Desert region, separate Chile from most of the neotropical fauna, as is shown by the absence of important tribes such as the Galeritini, Scaritini, and Brachinini. Keys for all genera present in Chile are provided, with a brief description of habitat and species richness of each

  11. Oxygen at nanomolar levels reversibly suppresses process rates and gene expression in anammox and denitrification in the oxygen minimum zone off northern Chile.

    Science.gov (United States)

    Dalsgaard, Tage; Stewart, Frank J; Thamdrup, Bo; De Brabandere, Loreto; Revsbech, Niels Peter; Ulloa, Osvaldo; Canfield, Don E; DeLong, Edward F

    2014-10-28

    A major percentage (20 to 40%) of global marine fixed-nitrogen loss occurs in oxygen minimum zones (OMZs). Concentrations of O2 and the sensitivity of the anaerobic N2-producing processes of anammox and denitrification determine where this loss occurs. We studied experimentally how O2 at nanomolar levels affects anammox and denitrification rates and the transcription of nitrogen cycle genes in the anoxic OMZ off Chile. Rates of anammox and denitrification were reversibly suppressed, most likely at the enzyme level. Fifty percent inhibition of N2 and N2O production by denitrification was achieved at 205 and 297 nM O2, respectively, whereas anammox was 50% inhibited at 886 nM O2. Coupled metatranscriptomic analysis revealed that transcripts encoding nitrous oxide reductase (nosZ), nitrite reductase (nirS), and nitric oxide reductase (norB) decreased in relative abundance above 200 nM O2. This O2 concentration did not suppress the transcription of other dissimilatory nitrogen cycle genes, including nitrate reductase (narG), hydrazine oxidoreductase (hzo), and nitrite reductase (nirK). However, taxonomic characterization of transcripts suggested inhibition of narG transcription in gammaproteobacteria, whereas the transcription of anammox narG, whose gene product is likely used to oxidatively replenish electrons for carbon fixation, was not inhibited. The taxonomic composition of transcripts differed among denitrification enzymes, suggesting that distinct groups of microorganisms mediate different steps of denitrification. Sulfide addition (1 µM) did not affect anammox or O2 inhibition kinetics but strongly stimulated N2O production by denitrification. These results identify new O2 thresholds for delimiting marine nitrogen loss and highlight the utility of integrating biogeochemical and metatranscriptomic analyses. The removal of fixed nitrogen via anammox and denitrification associated with low O2 concentrations in oceanic oxygen minimum zones (OMZ) is a major sink in

  12. Caracterización trófica del placóforo intermareal Enoplochiton niger en el norte de Chile: variación ambiental y patrones dietarios a nivel local y region Trophic characterization of the intertidal placophoran Enoplochiton niger in northern Chile: environmental variation and dietary patterns at local and regional levels

    Directory of Open Access Journals (Sweden)

    ALVARO G SANHUEZA

    2008-12-01

    .The role and impact of herbivores on rocky intertidal food webs could be more complex and diverse than previously considered, particularly in the case of larger and more abundant consumers such as the placophoran mollusc Enoplochiton niger. This species is one of the largest (up to 20 cm and ecologically most important grazers on rocky shores of northern Chile, but also one of the lesser known species in trophic terms. This work presents an assessment of the dietary patterns of E. niger in four communities of northern Chile, distributed along 1,000 km of coastline and sampled seasonally from winter 2004 to autumn 2006. The analysis included the relationship of its diet with physical and biological factors, and particularly the potential effect of the 2004-2005 El Niño event that occurred during the study period. At a regional level, the dietary spectrum of E. niger comprised a total of 98 food resources (60 algal Ítems and 38 invertebrate Ítems, and the most important Ítems were sessile organisms of encrusting and layer-forming growth habits. E. niger exhibited a very high niche breadth at both local and regional levels (ranging from 20.7 to 28.0; Levins' index, and its dietary richness at the individual level was independent from its body size. Both the number of dietary ítems consumed per individual and the taxonomic composition of the diet did not show statistical differences among communities, but they were significantly different between the El Niño and non-El Niño periods. There was no clear relationship between the dietary patterns of E. niger and the contrasting levels of upwelling intensity among the communities studied. The results show that E. niger is a generalist polyphagous consumer, and a potential omnivore, which could have a high level of impact on space occupancy patterns in the intertidal community.

  13. 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...

  14. Heavy mineral as a tool to refine the stratigraphy of kaolin deposits in the Rio Capim Area, Northern Brazil

    Directory of Open Access Journals (Sweden)

    Ana M. Góes

    2007-09-01

    Full Text Available Studies of heavy minerals in kaolin deposits from the Ipixuna Formation in the Rio Capim area (Northern Brazil showed a mature to super mature assemblage dominated by zircon and tourmaline, and subordinately rutile, kyanite and staurolite. These minerals do not change much throughout the whole section; however, each kaolin unit displays a particular signature, defined by differences in the proportions of the whole assemblage of heavy minerals, as well as of their textural characteristics. This work revealed that the lower and upper kaolin units can be definitely considered as distinct depositional sequences. A higher proportion of opaque minerals and higher zircon values characterize the lower unit. The higher volumes of anhedric, rounded to sub-rounded grains of zircon and tourmaline in the upper unit suggests that this includes grains that were undergone to a higher degree of reworking. The increased volume of unaltered staurolite and kyanite in the upper unit leads to conclude that, even considering sediment reworking, a distinct source must be invoked. The results also show that the characteristics of the heavy mineral assemblage from the intermediate unit are comparable with those from the upper unit, which suggests they might record a same stratigraphic sequence.Estudos de minerais pesados provenientes em depósitos cauliníticos da Formação Ipixuna na região do rio Capim (Brasil revelaram uma mineralogia matura a supermatura, representada dominantemente por zircão e turmalina e, subordinadamente, rutilo, cianita e estaurolita. Os minerais encontrados não variam muito, entretanto cada unidade caulinítica apresenta uma assinatura particular definida por diferenças nasproporções entre os principais minerais, assim como em suas características texturais. Este trabalho demonstrou que asunidades de caulim soft (inferior e semi-flint (superior podem ser consideradas seqüências deposicionais distintas. As altas percentagens de opacos

  15. Survival of brown trout during spring flood in DOC-rich streams in northern Sweden: the effect of present acid deposition and modelled pre-industrial water quality

    International Nuclear Information System (INIS)

    Laudon, Hjalmar; Poleo, Antonio B.S.; Voellestad, Leif Asbjoern; Bishop, Kevin

    2005-01-01

    Mortality and physiological responses in brown trout (Salmo trutta) were studied during spring snow melt in six streams in northern Sweden that differed in concentrations of dissolved organic carbon (DOC) and pH declines. Data from these streams were used to create an empirical model for predicting fish responses (mortality and physiological disturbances) in DOC-rich streams using readily accessible water chemistry parameters. The results suggest that fish in these systems can tolerate higher acidity and inorganic aluminium levels than fish in low DOC streams. But even with the relatively low contemporary deposition load, anthropogenic deposition can cause fish mortality in the most acid-sensitive surface waters in northern Sweden during spring flood. However, the results suggests that it is only in streams with high levels of organically complexed aluminium in combination with a natural pH decline to below 5.0 during the spring where current sulphur deposition can cause irreversible damage to brown trout in the region. This study support earlier studies suggesting that DOC has an ameliorating effect on physiological disturbances in humic waters but the study also shows that surviving fish recover physiologically when the water quality returns to less toxic conditions following a toxic high flow period. The physiological response under natural, pre-industrial conditions was also estimated. - High levels of complexed aluminum, at pH levels below 5.0, predisposes brown trout to sulfur-caused damage in the spring

  16. Survival of brown trout during spring flood in DOC-rich streams in northern Sweden: the effect of present acid deposition and modelled pre-industrial water quality

    Energy Technology Data Exchange (ETDEWEB)

    Laudon, Hjalmar [Department of Forest Ecology, Swedish University of Agricultural Sciences, SE-901 83 Umeaa (Sweden)]. E-mail: hjalmar.laudon@sek.slu.se; Poleo, Antonio B.S. [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Voellestad, Leif Asbjoern [Department of Biology, University of Oslo, P.O. Box 1066 Blindern, N-0316 Oslo (Norway); Bishop, Kevin [Department of Environmental Assessment, Swedish University of Agricultural Sciences, SE-750 07 Uppsala (Sweden)

    2005-05-01

    Mortality and physiological responses in brown trout (Salmo trutta) were studied during spring snow melt in six streams in northern Sweden that differed in concentrations of dissolved organic carbon (DOC) and pH declines. Data from these streams were used to create an empirical model for predicting fish responses (mortality and physiological disturbances) in DOC-rich streams using readily accessible water chemistry parameters. The results suggest that fish in these systems can tolerate higher acidity and inorganic aluminium levels than fish in low DOC streams. But even with the relatively low contemporary deposition load, anthropogenic deposition can cause fish mortality in the most acid-sensitive surface waters in northern Sweden during spring flood. However, the results suggests that it is only in streams with high levels of organically complexed aluminium in combination with a natural pH decline to below 5.0 during the spring where current sulphur deposition can cause irreversible damage to brown trout in the region. This study support earlier studies suggesting that DOC has an ameliorating effect on physiological disturbances in humic waters but the study also shows that surviving fish recover physiologically when the water quality returns to less toxic conditions following a toxic high flow period. The physiological response under natural, pre-industrial conditions was also estimated. - High levels of complexed aluminum, at pH levels below 5.0, predisposes brown trout to sulfur-caused damage in the spring.

  17. New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

    Science.gov (United States)

    Carmichael, Sarah K.; Doctor, Daniel H.; Wilson, Crystal G.; Feierstein, Joshua; McAleer, Ryan J.

    2017-01-01

    Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace and rare earth element (REE) geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered alluvial deposits that occur close to breccia-hosted Mn deposits in Virginia show geochemical signatures that are distinct from the breccia matrices and appear to reflect remobilization of earlier-emplaced Mn and concentration within supergene traps. Based on the proximity of all of the productive ore deposits to mapped faults or other zones of deformation, we suggest that the primary source of all of the Mn may have been deep seated, and that Mn oxides with supergene and/or biological characteristics resulted from the local remobilization and concentration of this primary Mn.

  18. Larval fish feeding ecology, growth and mortality from two basins with contrasting environmental conditions of an inner sea of northern Patagonia, Chile.

    Science.gov (United States)

    Landaeta, Mauricio F; Bustos, Claudia A; Contreras, Jorge E; Salas-Berríos, Franco; Palacios-Fuentes, Pámela; Alvarado-Niño, Mónica; Letelier, Jaime; Balbontín, Fernando

    2015-05-01

    During austral spring 2011, a survey was carried out in the inland sea (41°30'-44°S) of north Patagonia, South Pacific, studying a northern basin (NB: Reloncaví Fjord, Reloncaví Sound and Ancud Gulf) characterized by estuarine regime with stronger vertical stratification and warmer (11-14 °C) and most productive waters, and a southern basin (SB: Corcovado Gulf and Guafo mouth), with more oceanic water influence, showed mixed conditions of the water column, colder (11-10.5 °C) and less productive waters. Otolith microstructure and gut content analysis of larval lightfish Maurolicus parvipinnis and rockfish Sebastes oculatus were studied. Larval M. parvipinnis showed similar growth rates in both regions (0.13-0.15 mm d(-1)), but in NB larvae were larger-at-age than in SB. Larval S. oculatus showed no differences in size-at-age and larval growth (0.16 and 0.11 mm d(-1) for NB and SB, respectively). M. parvipinnis larvae from NB had larger number of prey items (mostly invertebrate eggs), similar total volume in their guts and smaller prey size than larvae collected in SB (mainly calanoid copepods). Larval S. oculatus had similar number, volume and body width of prey ingested at both basins, although prey ingestion rate by size was 5 times larger in NB than in SB, and prey composition varied from nauplii in NB to copepodites in SB. This study provides evidence that physical-biological interactions during larval stages of marine fishes from Chilean Patagonia are species-specific, and that in some cases large size-at-age correspond to increasing foraging success. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. A contribution to the hazards assessment at Copahue volcano (Argentina-Chile) by facies analysis of a recent pyroclastic density current deposit

    Science.gov (United States)

    Balbis, C.; Petrinovic, I. A.; Guzmán, S.

    2016-11-01

    We recognised and interpreted a recent pyroclastic density current (PDC) deposit at the Copahue volcano (Southern Andes), through a field survey and a sedimentological study. The relationships between the behaviour of the PDCs, the morphology of the Río Agrio valley and the eruptive dynamics were interpreted. We identified two lithofacies in the deposit that indicate variations in the eruptive dynamics: i) the opening of the conduit and the formation of a highly explosive eruption that formed a diluted PDC through the immediate collapse of the eruptive column; ii) a continued eruption which followed immediately and records the widening of the conduit, producing a dense PDC. The eruption occurred in 2000 CE, was phreatomagmatic (VEI ≤ 2), with a vesiculation level above 4000 m depth and fragmentation driven by the interaction of magma with an hydrothermal system at ca. 1500 m depth. As deduced from the comparison between the accessory lithics of this deposit and those of the 2012 CE eruption, the depth of onset of vesiculation and fragmentation level in this volcano is constant in depth. In order to reproduce the distribution pattern of this PDC's deposit and to simulate potential PDC's forming-processes, we made several computational modelling from "denser" to "more diluted" conditions. The latter fairly reproduces the distribution of the studied deposit and represents perhaps one of the most dangerous possible scenarios of the Copahue volcanic activity. PDCs occurrence has been considered in the last volcanic hazards map as a low probability process; evidences found in this contribution suggest instead to include them as more probable and thus very important for the hazards assessment of the Copahue volcano.

  20. Comparison of Spheroidal Carbonaceous Particle Data with Modelled Atmospheric Black Carbon Concentration and Deposition and Air Mass Sources in Northern Europe, 1850–2010

    Directory of Open Access Journals (Sweden)

    Meri Ruppel

    2013-01-01

    Full Text Available Spheroidal carbonaceous particles (SCP are a well-defined fraction of black carbon (BC, produced only by the incomplete combustion of fossil fuels such as coal and oil. Their past concentrations have been studied using environmental archives, but, additionally, historical trends of BC concentration and deposition can be estimated by modelling. These models are based on BC emission inventories, but actual measurements of BC concentration and deposition play an essential role in their evaluation and validation. We use the chemistry transport model OsloCTM2 to model historical time series of BC concentration and deposition from energy and industrial sources and compare these to sedimentary measurements of SCPs obtained from lake sediments in Northern Europe from 1850 to 2010. To determine the origin of SCPs we generated back trajectories of air masses to the study sites. Generally, trends of SCP deposition and modelled results agree reasonably well, showing rapidly increasing values from 1950, to a peak in 1980, and a decrease towards the present. Empirical SCP data show differences in deposition magnitude between the sites that are not captured by the model but which may be explained by different air mass transport patterns. The results highlight the need for numerous observational records to reliably validate model results.

  1. Five-year records of mercury wet deposition flux at GMOS sites in the Northern and Southern hemispheres

    CSIR Research Space (South Africa)

    Sprovieri, F

    2017-02-01

    Full Text Available samples were collected for approximately 5 years at 17 selected GMOS monitoring sites located in the Northern and Southern hemispheres in the framework of the Global Mercury Observation System (GMOS) project. Total mercury (THg) exhibited annual...

  2. The Aysen Glacier Trail (AGT): Fostering leadership and personal growth towards understanding our place in the environment through experiential learning and scientific inquiry in northern Patagonia, Chile

    Science.gov (United States)

    Sincavage, R.; Chambers, F. B.; Leidich, J.

    2017-12-01

    The Colonia Glacier, a low elevation mid-latitude glacier, drains the lee side of the central division of the Northern Patagonian Ice Field (NPI). As such, it serves as a microcosm of conditions on the NPI as a whole. Glaciers of this type have experienced extreme variability in Holocene thickness and extent, making them excellent indicators of local and regional climate conditions. Glacial lake outburst floods (GLOFs) originating in the remote Cachet Basin, dammed by the Colonia Glacier, have increased in frequency from once every 10 years to 3 times annually since 2008. These flood events are important in that they 1.) directly impact the livelihoods of downstream residents, 2.) may be linked to the overall health of the Colonia Glacier and, to a larger extent, the NPI, 3.) provide a natural laboratory for studying the dynamics of large flood events, and 4.) have downcut the sediments sequestered in the upper basin, revealing a rich Holocene sedimentologic and climate record. With improved access to this remote region through local partners in recent years, outstanding opportunities for scientific discovery, education, and outreach exist in one of the most beautiful and least-studied glacial regions on Earth. We propose establishing an NSF REU site here to further develop the abundant educational and research opportunities in this spectacular locale. We envision students participating under the REU will receive a broad-based background in glaciology and sedimentology prior to the field experience, and then participate in basic field research led by the PIs into understanding recent and Holocene linkages between climate change and the glacio-fluvio geomorphology of the NPI. A pilot program of 13 U.S. and Chilean students with wide-ranging backgrounds and degree levels was conducted in the winter of 2015-16. A two week backcountry trek across rocky terrain, mountain streams, active glaciers, and proglacial lakes in this seldom-visited region immersed the students

  3. Gold and copper deposits in Central Lapland, Northern Finland, with special reference to their exploration and exploitation

    OpenAIRE

    Korkalo, T. (Tuomo)

    2006-01-01

    Abstract At least 30 gold deposits verified by means of one or more notable diamond drill hole results have been discovered in Central Lapland in the last 20 years, and these can be divided spatially into groups, between which the metal composition varies. The deposits contain varying amounts of sulphides and sulpharsenides as well as gold. Pyrite is the most common sulphide mineral in the gold deposits associated with volcanic rocks, and usually pyrrhotite in those associated with sedimen...

  4. A preliminary analysis and assessment of hydrogeological conditions for in-situ leach mining of sandstone-type uranium deposit in northern Ordos basin

    International Nuclear Information System (INIS)

    Chen Fazheng; Zhao Jinfeng; Chang Baocheng; Gao Junyi

    2006-01-01

    A systematic analysis and assessment on hydrogeologic condition, the lithology and hydrogeologic structure of ore-hosting aquitfers, hydrodynamic condition, hydrochemical characteristics at a sandstone-type uranium deposit in northern Ordos basin is made in this paper. It has been concluded, that hydrogeologic condition in the study area is favorable, meeting the requirements for in-situ leach mining of the deposit. Aimed at the low artesian pressure head and low water output and based on the results of pumping-injection tests which led to the significant increase of water output, a technical scheme of pressured water injection has been proposed to artificially raise the artesian pressure head and increase the output of groundwater to satisfy the requirements of in-situ leach mining. (authors)

  5. Petrology and geochemistry of the orbicular granitoid of Caldera, northern Chile. Models and hypotheses on the formation of radial orbicular textures

    Science.gov (United States)

    Díaz-Alvarado, Juan; Rodríguez, Natalia; Rodríguez, Carmen; Fernández, Carlos; Constanzo, Ítalo

    2017-07-01

    The orbicular granitoid of Caldera, located at the northern part of the Chilean Coastal Range, is a spectacular example of radial textures in orbicular structures. The orbicular body crops out as a 375 m2 tabular to lensoidal intrusive sheet emplaced in the Lower Jurassic Relincho pluton. The orbicular structures are 3-7 cm in diameter ellipsoids hosted in a porphyritic matrix. The orbicules are comprised by a Qtz-dioritic core (3-5 cm in diameter) composed by Pl + Hbl + Qtz + Bt ± Kfs with equiaxial textures and a gabbroic shell (2-3 cm in diameter) characterized by feathery and radiate textures with a plagioclase + hornblende paragenesis. The radial shell crystals are rooted and orthogonally disposed in the irregular contact with the core. The radial shell, called here inner shell, is in contact with the granodioritic equiaxial interorbicular matrix through a 2-3 mm wide poikilitic band around the orbicule (outer shell). The outer shell and the matrix surrounding the orbicules are characterized by the presence of large hornblende and biotite oikocrystals that include fine-grained rounded plagioclase and magnetite. The oikocrystals of both the outer shell and the matrix have a circumferential arrangement around the orbicule, i.e. orthogonal to the radial inner shell. The coarse-grained granodioritic interorbicular matrix present pegmatitic domains with large acicular hornblende and K-feldspar megacrysts. This work presents a review of the textural characteristics of the orbicules and a complete new mineral and whole-rock geochemical study of the different parts of the orbicular granitoid, together with thermobarometric and crystallographic data, and theoretical modeling of the crystallization and element partitioning processes. We propose a model for the formation of the orbicular radial textures consisting of several processes that are suggested to occur fast and consecutively: superheating, volatile exsolution, undercooling, geochemical fractionation and

  6. Responses of nitrogen and carbon deposition rates in Comau Fjord (42°S, southern Chile) to natural and anthropogenic impacts during the last century

    Science.gov (United States)

    Mayr, Christoph; Rebolledo, Lorena; Schulte, Katharina; Schuster, Astrid; Zolitschka, Bernd; Försterra, Günter; Häussermann, Verena

    2014-04-01

    Carbon isotopes and C/N ratios are frequently used to separate allochthonous and autochthonous organic matter input into marine shelf sediments. We test the applicability of this approach for the sediment record from Comau Fjord in southern Chile (42°S) with the aim to reconstruct carbon and nitrogen mass accumulation rates and to determine their allochthonous and autochthonous sources for the last century. Comparisons with isotopic and geochemical signatures of potential organic matter sources demonstrate that mixtures between terrigenous soil and peat on the one hand and marine planktonic organic matter on the other hand readily explain variations of organic carbon (δ13Corg) and nitrogen (δ15N) isotopes as well as in C/N and N/C ratios and explain differences in absolute values of these parameters along a transect of cores. Nitrogen mass accumulation rates, calculated from δ15N and C/N ratio, and carbon mass accumulation rates, calculated from δ13Corg and N/C ratios of terrigenous organic matter, varied considerably less compared to those of autochthonous planktonic organic matter. Autochthonous carbon accumulation rates increased from between 1.2 and 5.2 g m-2 a-1 at the beginning of the last century to values between 21.5 and 29.9 g m-2 a-1 around the turn of the millennium. Even if the highest amount of diagenetic degradation is considered the mass accumulation rates increased by at least a factor of 2 within the last decades of the 20th century. The reasons for such a shift in primary productivity are discussed (1) in terms of recent climatic change in northwestern Patagonia possibly having lowered fluvial inflow into Comau Fjord and (2) in relation to anthropogenic eutrophication by rapidly expanding aquaculture. Given that allochthonous mass-accumulation rates remained fairly constant, we conclude that anthropogenic eutrophication caused by aquaculture is the more likely explanation for increased carbon and nitrogen accumulation rates in the last two

  7. Facies analysis, depositional environments and paleoclimate of the Cretaceous Bima Formation in the Gongola Sub - Basin, Northern Benue Trough, NE Nigeria

    Science.gov (United States)

    Shettima, B.; Abubakar, M. B.; Kuku, A.; Haruna, A. I.

    2018-01-01

    Facies analysis of the Cretaceous Bima Formation in the Gongola Sub -basin of the Northern Benue Trough northeastern Nigeria indicated that the Lower Bima Member is composed of alluvial fan and braided river facies associations. The alluvial fan depositional environment dominantly consists of debris flow facies that commonly occur as matrix supported conglomerate. This facies is locally associated with grain supported conglomerate and mudstone facies, representing sieve channel and mud flow deposits respectively, and these deposits may account for the proximal alluvial fan region of the Lower Bima Member. The distal fan facies were represented by gravel-bed braided river system of probably Scot - type model. This grade into sandy braided river systems with well developed floodplains facies, forming probably at the lowermost portion of the alluvial fan depositional gradient, where it inter-fingers with basinal facies. In the Middle Bima Member, the facies architecture is dominantly suggestive of deep perennial sand-bed braided river system with thickly developed amalgamated trough crossbedded sandstone facies fining to mudstone. Couplets of shallow channels are also locally common, attesting to the varying topography of the basin. The Upper Bima Member is characterized by shallow perennial sand-bed braided river system composed of successive succession of planar and trough crossbedded sandstone facies associations, and shallower channels of the flashy ephemeral sheetflood sand - bed river systems defined by interbedded succession of small scale trough crossbedded sandstone facies and parallel laminated sandstone facies. The overall stacking pattern of the facies succession of the Bima Formation in the Gongola Sub - basin is generally thinning and fining upwards cycles, indicating scarp retreat and deposition in a relatively passive margin setting. Dominance of kaolinite in the clay mineral fraction of the Bima Formation points to predominance of humid sub - tropical

  8. Topographic and depositional signature of old anthropic lakes in northern part of the Moldavian Plateau (NE Romania)

    Science.gov (United States)

    Ciprian Margarint, Mihai; Niculita, Mihai; Nemeth, Alexandra; Cristea, Ionut

    2017-04-01

    The role of humans and theirs social activities in reshaping earth surface is obvious in many places of the world. Anthropic fingerprints on Earth's surface morphology are recognizable by theirs topographic and depositional signatures that can cause considerable changes in geomorphological organization of the landscape, with direct consequences on Earth surface processes. Anthropic dams and their associated sediments represent recent archives that record environmental changes. They can provide substantial data to reconstruct general models in geomorphic evolution of hydrologic catchments and the identification of extreme meteorological events and sediment fluxes. Also, geochemical tracers provide us relevant indicators about climatic patterns and local condition of sedimentation processes. Until quite recently, the identification and counting the old lakes have been carried out mostly by studying different old maps and less by analyzing their fingerprints on the Earth surface. Considered a real revolution in geomorphology, the high-resolution LiDAR data allow us nowadays a more precise recognition of minor landforms, their extent and cross-relationships, as well as to discover surface features that have escaped the attention before. Furthermore, by using Electrical Resistivity Tomography techniques, the 3D extension of the sediments can be revealed. Anthropic lakes are one of the most particular hydrological anthropic features of the landscape in the northern part of the Moldavian Plateau (Eastern Carpathian lowland). The need for water supply, have forced the inhabitants to build dams of various sizes along the entire river network. Over the time, many dams were abandoned, while others have been relocated with an impressive dynamic at historical time scale. For more than 3000 sq km we have carried out an accurate inventory of abandoned dams using LIDAR imagery. Taking into consideration the last appearance of the lakes on the old maps, they were classified: pre

  9. Feeding and nutritional ecology of the edible sea urchin Loxechinus albus in the northern Chilean coast Ecología nutricional y alimenticia del erizo comestible Loxechinus albus en el norte de Chile

    Directory of Open Access Journals (Sweden)

    SOLANGE J GONZÁLEZ

    2008-12-01

    Full Text Available The red sea urchin Loxechinus albus, an economically important species oceurring along the Chilean littoral benthic systems, has been heavily exploited by artisanal fisheries in recent decades. However, basic knowledge of its trophic biology is still scarce. Studies of this kind are critical to the successful development of farming techniques as an alternative to the harvest of natural populations. The aims of this study were to quantify the composition of L. albus' natural diet, to determine the assimilation efficieney of the most important dietary components, and to experimentally examine the species' trophic selectivity. Adult and juvenile specimens were sampled in spring 1993 and summer, fall and winter 1994 from the shallow subtidal zone of Iquique, northern Chile. Neither juveniles ñor adults showed significant seasonal differences in dietary composition. The main Ítems in the diet were the green alga Ulva sp. for juveniles and the kelp Lessonia sp. for adults. In adults, assimilation efficieney (as percentage of the total organic matter ingested was not significantly different among individuals that consumed Lessonia sp. (48.7 %, Ulva sp. (44.6 % and Macrocystis (38.1 %, whereas in juveniles assimilation efficieney was significantly higher for individuals fed on the chlorophyte Ulva sp. (55.4 %, followed by Lessonia sp. (35.0 % and Macrocystis (25.5 %. These results suggest that L. albus undergoes an ontogenetic shift in the diet, consisting of a differential foraging strategy between juveniles and adults.El erizo Loxechinus albus (Molina, 1782 es un recurso de gran importancia económica en los sistemas bentónicos costeros, y que se encuentra bajo una fuerte presión de explotación. Sin embargo, los antecedentes sobre diversos aspectos básicos de su biología trófica son aún escasos. Estudios de esta naturaleza son importantes en razón a que constituyen la base para el desarrollo de técnicas de cultivo exitosas, alternativa a la

  10. Effects of sulfate deposition on pore water dissolved organic carbon, nutrients, and microbial enzyme activities in a northern peatland

    Science.gov (United States)

    L.R. Seifert-Monson; B.H. Hill; R.K. Kolka; T.M. Jicha; L.L. Lehto; C.M. Elonen

    2014-01-01

    Export of dissolved organic carbon from lakes and streams has increased throughout Europe and North America over the past several decades. One possible cause is altered deposition chemistry; specifically, decreasing sulfate inputs leading to changes in ionic strength and dissolved organic carbon solubility. To further investigate the relationship between deposition...

  11. Sedimentation of the basal Kombolgie Formation (Upper Precambrian-Carpentarian) Northern Territory, Australia: possible significance in the genesis of the underlying Alligator Rivers unconformity-type uranium deposits

    International Nuclear Information System (INIS)

    Ojakangas, R.W.

    1979-10-01

    The 1400 to 1500 My old Kombolgie Formation of the MacArthur Basin of the Northern Territory overlies or has overlain unconformity-type uranium deposits including Jabiluka, Ranger, Koongarra, Nabarlek and the small deposits of the South Alligator River Valley. A brief study of the basal portion of the formation showed it to consist entirely of mature conglomerates and quartzose sandstones. Analysis of the bedding types (planar cross beds, trough cross beds and parallel beds) and other sedimentary structures (mainly ripple marks and parting lineation) fit a braided alluvial plain model. A paleocurrent study utilizing about 400 measurements from nine localities located along the westward-facing 250 kilometer-long erosional escarpment of the Arnhem Land Plateau showed the dominant paleocurrent trend to be from west and northwest towards the east and southeast, with local divergence. The data and interpretation presented are relevant to the supergene model of uranium deposition at the unconformity, for they add to the suggestion that additional uranium deposits similar to Jabiluka Two may underlie the Kombolgie Formation eastward from the present escarpment

  12. Identification of Zn-Bearing Micas and Clays from the Cristal and Mina Grande Zinc Deposits (Bongará Province, Amazonas Region, Northern Peru

    Directory of Open Access Journals (Sweden)

    Giuseppe Arfè

    2017-11-01

    Full Text Available Zn-bearing phyllosilicates are common minerals in nonsulfide Zn deposits, but they seldom represent the prevailing economic species. However, even though the presence of Zn-bearing clays is considered as a disadvantage in mineral processing, their characteristics can give crucial information on the genesis of the oxidized mineralization. This research has been carried out on the Mina Grande and Cristal Zn-sulfide/nonsulfide deposits, which occur in the Bongará district (Northern Peru. In both of the deposits, Zn-bearing micas and clays occur as an accessory to the ore minerals. The XRD analyses and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS investigations revealed that the Zn-bearing micas that are occurring in both deposits mostly consist of I/S mixed layers of detrital origin, which have been partly altered or overprinted by sauconite during the supergene alteration of sulfides. Sporadic hendricksite was also identified in the Cristal nonsulfide mineral assemblage, whereas at Mina Grande, the fraipontite-zaccagnaite (3R-polytype association was detected. The identified zaccagnaite polytype suggests that both fraipontite and zaccagnaite are genetically related to weathering processes. The hendricksite detected at Cristal is a product of hydrothermal alteration, which is formed during the emplacement of sulfides. The complex nature of the identified phyllosilicates may be considered as evidence of the multiple processes (hydrothermal and supergene that occurred in the Bongará district.

  13. Late Paleozoic SEDEX deposits in South China formed in a carbonate platform at the northern margin of Gondwana

    Science.gov (United States)

    Qiu, Wenhong Johnson; Zhou, Mei-Fu; Liu, Zerui Ray

    2018-05-01

    SEDEX sulfide deposits hosted in black shale and carbonate are common in the South China Block. The Dajiangping pyrite deposit is the largest of these deposits and is made up of stratiform orebodies hosted in black shales. Sandstone interlayered with stratiform orebodies contains detrital zircon grains with the youngest ages of 429 Ma. Pyrite from the orebodies has a Re-Os isochron age of 389 ± 62 Ma, indicative of formation of the hosting strata and syngenetic pyrite ores in the mid-late Devonian. The hosting strata is a transgression sequence in a passive margin and composed of carbonaceous limestone in the lower part and black shales in the upper part. The ore-hosting black shales have high TOC (total organic carbon), Mo, As, Pb, Zn and Cd, indicating an anoxic-euxinic deep basin origin. The high redox proxies, V/(V + Ni) > 0.6 and V/Cr > 1, and the positive correlations of TOC with Mo and V in black shales are also consistent with an anoxic depositional environment. The Dajiangping deposit is located close to the NE-trending Wuchuan-Sihui fault, which was active during the Devonian. The mid-late Devonian mineralization age and the anoxic-euxinic deep basinal condition of this deposit thus imply that the formation of this deposit was causally linked to hydrothermal fluid exhalation in an anoxic fault-bounded basin that developed in a carbonate platform of the South China Block. The regional distribution of many Devonian, stratiform, carbonaceous sediment-hosted sulfide deposits along the NE-trending fault-bounded basins in South China, similar to the Dajiangping deposit, indicates that these deposits formed at a basin developed in the passive margin setting of the South China Block during the Devonian. This environment was caused by the break-up and northward migration of the South China Block from Gandwana.

  14. Concentración de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y sedimentos de una playa artificial, en la bahía San Jorge 23°S, norte de Chile Heavy metals concentration (Cu, Ni, Zn, Cd, Pb, in biota and sediments of an artificial beach, in San Jorge bay 23°S, northern Chile

    Directory of Open Access Journals (Sweden)

    Gabriel Castro

    2012-07-01

    Full Text Available Se evaluó el contenido de metales pesados (Cu, Ni, Zn, Cd, Pb en la biota y el sedimento de una playa artificial (Paraíso y una playa natural (El Lenguado, ubicadas en la bahía San Jorge, norte de Chile. Los resultados fueron utilizados para comparar ambos sistemas, el grado de cumplimiento de la normativa ambiental nacional e internacional, y el efecto de la construcción de la playa artificial sobre el nivel de contaminación por metales existentes históricamente en esa zona. En cada playa se ubicaron estaciones equidistantes que abarcaron desde el intermareal hasta el submareal de las cuales fueron extraídos los organismos. Se tomaron muestras de sedimento en cada playa y se determinaron las pendientes con el método de Emery. El análisis granulométrico evidenció el predominio de arena media en playa El Lenguado, y arena media y fina en playa Paraíso. El contenido de materia orgánica fue mayor en El Lenguado. En playa Paraíso se determinaron cinco phylum/superclase agrupados en 19 taxa, mientras que en El Lenguado se encontraron cuatro phylum/superclase agrupados en cc taxa. El contenido de metales en sedimentos y en la mayoría de organismos presentó valores mayores en playa Paraíso. Estos resultados, junto a las normas de calidad chilenas y norteamericanas, sugieren un evidente deterioro en la calidad ambiental de playa Paraíso lo que se demostró por un incremento en las concentraciones de estos metales desde su construcción, los que sobrepasan los límites establecidos por ambas normas.It was evaluated the heavy metal content (Cu, Ni, Zn, Cd, Pb in biota and sediment of an artificial beach (Paraíso and a natural beach (El Lenguado, both located in San Jorge bay, northern Chile. The results were used to compare both systems, the degree of fulfillment of national and international environmental regulations, and the effect of the construction of the artificial beach on the level of metal contamination historically existing in

  15. Forecasting of reservoir pressures of oil and gas bearing complexes in northern part of West Siberia for safety oil and gas deposits exploration and development

    Science.gov (United States)

    Gorbunov, P. A.; Vorobyov, S. V.

    2017-10-01

    In the paper the features of reservoir pressures changes in the northern part of West Siberian oil-and gas province are described. This research is based on the results of hydrodynamic studies in prospecting and explorating wells in Yamal-Nenets Autonomous District. In the Cenomanian, Albian, Aptian and in the top of Neocomian deposits, according to the research, reservoir pressure is usually equal to hydrostatic pressure. At the bottom of the Neocomian and Jurassic deposits zones with abnormally high reservoir pressures (AHRP) are distinguished within Gydan and Yamal Peninsula and in the Nadym-Pur-Taz interfluve. Authors performed the unique zoning of the territory of the Yamal-Nenets Autonomous District according to the patterns of changes of reservoir pressures in the section of the sedimentary cover. The performed zoning and structural modeling allow authors to create a set of the initial reservoir pressures maps for the main oil and gas bearing complexes of the northern part of West Siberia. The results of the survey should improve the efficiency of exploration drilling by preventing complications and accidents during this operation in zones with abnormally high reservoir pressures. In addition, the results of the study can be used to estimate gas resources within prospective areas of Yamal-Nenets Autonomous District.

  16. Systematic Lithologic Calibration of Neogene Mass-Transport Deposits Seismic Character in Mississippi Canyon of the Northern Gulf of Mexico, USA.

    Science.gov (United States)

    Gutierrez, M. A.; Snedden, J.

    2017-12-01

    Few publications have attempted detailed lithologic calibration of Mass Transport Deposits, usually as a byproduct of mud log descriptions. While the principal motivation for further understanding these slope failure deposits are driven by the economics of deep-water hydrocarbon exploration, the geohazard-related risks of storm-wave loading, and the shallow gas, also provide a driving concern for these deposits. Such risks can be mitigated and prevented by in depth analysis of slope stability and failure. The Mississippi Canyon of the Northern Gulf of Mexico is one of the few basins to contain enough available density of seismic and well data to provide a well-constrained lithologic characterization throughout a MTD-rich continental margin. The proposed hypothesis evaluates: 1) the differences between attached and detached MTDs in the Neogene Northern Gulf of Mexico through seismic characterization and well log analysis, 2) variations of MTD dimensions and map geometries in relation to depositional age throughout the northeastern and northcentral Gulf of Mexico, and 3) the differentiation between sand-prone and shale-prone MTD's in relation to associated depositional mechanisms. This study will attempt lithologic calibration of MTDs in Pleistocene -Miocene strata of the study area through integration of seismic observations (focused in supra-salt basins, which have the highest seismic data quality) and lithologic related information extracted from logs, mud logs (cuttings), and available core data to further constrain the distribution of MTD types, lithology, and geometries. Initial interpretations reflect a variance of seismic character responses to the presence of sandstone and shale (constrained by wells) throughout different regions and salt tectonic domains of the MTD geobodies. Further analysis will relate different seismic facies throughout MTDs to improve the understanding of seismic character and related lithologic facies throughout the deposits, in

  17. Effects of sulfate deposition on pore water dissolved organic carbon, nutrients, and microbial enzyme activities in a northern peatland

    Science.gov (United States)

    Export of dissolved organic carbon from lakes and streams has increased throughout Europe and North America over the past several decades. One possible cause is altered deposition chemistry; specifically, decreasing sulfate inputs leading to changes in ionic strength and dissolve...

  18. 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)

  19. Simulated Nitrogen Deposition has Minor Effects on Ecosystem Pools and Fluxes of Energy, Elements, and Biochemicals in a Northern Hardwoods Forest

    Science.gov (United States)

    Talhelm, A. F.; Pregitzer, K. S.; Burton, A. J.; Xia, M.; Zak, D. R.

    2017-12-01

    The elemental and biochemical composition of plant tissues is an important influence on primary productivity, decomposition, and other aspects of biogeochemistry. Human activity has greatly altered biogeochemical cycles in ecosystems downwind of industrialized regions through atmospheric nitrogen deposition, but most research on these effects focuses on individual elements or steps in biogeochemical cycles. Here, we quantified pools and fluxes of biomass, the four major organic elements (carbon, oxygen, hydrogen, nitrogen), four biochemical fractions (lignin, structural carbohydrates, cell walls, and soluble material), and energy in a mature northern hardwoods forest in Michigan. We sampled the organic and mineral soil, fine and coarse roots, leaf litter, green leaves, and wood for chemical analyses. We then combined these data with previously published and archival information on pools and fluxes within this forest, which included replicated plots receiving either ambient deposition or simulated nitrogen deposition (3 g N m-2 yr-1 for 18 years). Live wood was the largest pool of energy and all elements and biochemical fractions. However, the production of wood, leaf litter, and fine roots represented similar fluxes of carbon, hydrogen, oxygen, cell wall material, and energy, while nitrogen fluxes were dominated by leaf litter and fine roots. Notably, the flux of lignin via fine roots was 70% higher than any other flux. Experimental nitrogen deposition had relatively few significant effects, increasing foliar nitrogen, increasing the concentration of lignin in the soil organic horizon and decreasing pools of all elements and biochemical fractions in the soil organic horizon except nitrogen, lignin, and structural carbohydrates. Overall, we found that differences in tissue chemistry concentrations were important determinants of ecosystem-level pools and fluxes, but that nitrogen deposition had little effect on concentrations, pools, or fluxes in this mature forest

  20. 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

  1. Fluid Inclusion and Oxygen Isotope Constraints on the Origin and Hydrothermal Evolution of the Haisugou Porphyry Mo Deposit in the Northern Xilamulun District, NE China

    Directory of Open Access Journals (Sweden)

    Qihai Shu

    2017-01-01

    Full Text Available The Haisugou porphyry Mo deposit is located in the northern Xilamulun district, northeastern China. Based on alteration and mineralization styles and crosscutting relationships, the hydrothermal evolution in Haisugou can be divided into three stages: an early potassic alteration stage with no significant metal deposition, a synmineralization sericite-chlorite alteration stage with extensive Mo precipitation, and a postmineralization stage characterized by barren quartz and minor calcite and fluorite. The coexistence of high-salinity brine inclusions with low-salinity inclusions both in potassic alteration stage (~440°C and locally in the early time of mineralization stage (380–320°C indicates the occurrence of fluid boiling. The positive correlations between the homogenization temperatures and the salinities of the fluids and the low oxygen isotopic compositions (δ18Ofluid < 3‰ of the syn- to postmineralization quartz together suggest the mixing of magmatic fluids with meteoric water, which dominated the whole mineralization process. The early boiling fluids were not responsible for ore precipitation, whereas the mixing with meteoric water, which resulted in temperature decrease and dilution that significantly reduced the metal solubility, should have played the major role in Mo mineralization. Combined fluid inclusion microthermometry and chlorite geothermometer results reveal that ore deposition mainly occurred between 350 and 290°C in Haisugou.

  2. Research on metallogenic conditions of intersection-type uranium ore-deposits in Zhongdong area, Northern Guangdong province

    International Nuclear Information System (INIS)

    Wang Zhengqi; Wu Lieqin; Zhang Guoyu

    2007-12-01

    The methods following as field geological investigation, trace element geo- chemistry and isotope geochemistry were used in this project. Based on geological and geochemical characteristics of Xiaoshui uranium ore deposits in Zhongdong area, Xiazhuang ore-field, Guangdong province, it could be concluded that: (1) The Provenance of Cretaceous mantle is a enriched mantle; (2) Silicified zone-type and intersection-type uranium ore are distinctness in the metallogenic period and mineralization process, and main metallogenic period of Xiaoshui uranium ore-deposit is 73.5 Ma; (3) The sources of uranium mineralization substance derived from enriched mantle; and (4)The intersection-type high grade uranium deposits were controlled by substances derived from mantle (contain with U, CO 2 , F, et al), tracks of intersection of NWW-across with NNE-trending faults and lithology of diabase. (authors)

  3. Research on metallogenic conditions of intersection-type uranium ore-deposits in Zhongdong area, Northern Guangdong province

    Energy Technology Data Exchange (ETDEWEB)

    Zhengqi, Wang [East China Inst. of Technology, Fuzhou (China); [Beijing Research Inst. of Uranium Geology, Beijing (China); Lieqin, Wu [Institute No.290, CNNC, Shaoguan (China); Guoyu, Zhang [East China Inst. of Technology, Fuzhou (China)

    2007-12-15

    The methods following as field geological investigation, trace element geo- chemistry and isotope geochemistry were used in this project. Based on geological and geochemical characteristics of Xiaoshui uranium ore deposits in Zhongdong area, Xiazhuang ore-field, Guangdong province, it could be concluded that: (1) The Provenance of Cretaceous mantle is a enriched mantle; (2) Silicified zone-type and intersection-type uranium ore are distinctness in the metallogenic period and mineralization process, and main metallogenic period of Xiaoshui uranium ore-deposit is 73.5 Ma; (3) The sources of uranium mineralization substance derived from enriched mantle; and (4)The intersection-type high grade uranium deposits were controlled by substances derived from mantle (contain with U, CO{sub 2}, F, et al), tracks of intersection of NWW-across with NNE-trending faults and lithology of diabase. (authors)

  4. Evaluation of LANDSAT-2 (ERTS) images applied to geologic structures and mineral resources of South America. [Salar de Coposa, Chile and Salar of Uyuni, Bolivia

    Science.gov (United States)

    Carter, W. D. (Principal Investigator); Kowalik, W. S.

    1976-01-01

    The author has identified the following significant results. The Salar of Coposa is located in northern Chile along the frontier with Bolivia. The surface was divided into six general classes of materials. Analysis of LANDSAT image 1243-14001 by use of interactive multispectral computer (Image 100) enabled accurate repetition of these general classes based on reflectance. The Salar of Uyuni is the largest of the South American evaporite deposits. Using image 1243-13595, and parallel piped computer classification of reflectance units, the Salar was divided into nine classes ranging from deep to shallow water, water over salt, salt saturated with water, and several classes of dry salt.

  5. Modern processes of palynomorph deposition at lakes of the northern region of the Rio de Janeiro State, Brazil.

    Science.gov (United States)

    Luz, Cynthia F P da; Barth, Ortrud M; Silva, Cleverson G

    2010-09-01

    Palynological analysis of pollen, Pteridophyta spores and algae deposited in the superficial sediments at Lagoa de Cima and Lagoa do Campelo Lakes, located in the north of Rio de Janeiro state, was used to determine the spatial variation of the palynomorphs deposition. A total of 67 pollen types were identified at Lagoa de Cima, with an expressive contribution of regional arboreous taxa, hydrophytes and ruderal plants of the pastureland. The depositional pattern of palynomorphs depends on the fluvial leakage, the proximity of the local sedimentation to the inlet of the Imbé and Urubu Rivers and the bathymetry of lake bottom. The highest concentrations of palynomorphs were observed in the decentralized and less deeper area, without the interference of the northeastern wind. At Lagoa do Campelo, a total of 58 pollen types were identified, among which the majority of the pollen grains came from hydrophytes, with the highest concentrations found along the northeastern shore. The southeastern shore showed high percentages of pollen and spores with degraded exine and mechanical damage, due to the transport through the lake by the currents caused by the wind, confirmed by the depositional trend of damaged palinomorphs along the same direction as the prevailing winds.

  6. Preliminary discussion on prospecting potential for sandstone-type uranium deposits in meso-cenozoic basins, northern Ordos

    International Nuclear Information System (INIS)

    Di Yongqiang

    2002-01-01

    Characteristics of the regional stratigraphy, tectonic movement, geologic evolution and hydrogeology are briefly introduced. Using the metallogenic theory and prospecting criteria for interlayer oxidation zone sandstone-type uranium deposits, the author analyses the prospecting potential and main prospecting targets in the region, and proposes suggestions for further prospecting work as well

  7. 210Pb dating of sediments from the central and the northern Adriatic Sea: The deposition and preservation of sedimentary organic carbon

    International Nuclear Information System (INIS)

    Hamilton, T.; Fowler, S.; Miquel, J.C.; La Rosa, J.

    1996-04-01

    A central goal of the ELNA project is to assess the carbon assimilation capacity of the Northern Adriatic Sea. This requires fundamental quantitative information on budgets and sinks of organic carbon. Any change in carbon production in the water column should be reflected in the underlying sediments. Moreover, the fraction of particulate organic carbon reaching the sea floor which is subsequently preserved in the sediment will be strongly coupled to sediment accumulation and mixing. In this study a series of box cores were collected in order to characterize a hypothetical eutrophication gradient extending from the Po River outflow region in the north down to the shallow meso-Adriatic depression (Jabuka Pit). The main tasks assigned to IAEA-MEL were to provide 210 Pb derived sedimentation and dry-mass accumulation rates and to examine the possible correlations between sedimentary processes, the deposition and preservation of sedimentary organic carbon and pelagic primary productivity

  8. Nickeliferous minerals in the Cassiar Asbestos Deposit, Northern British Columbia (NTS 104/P/05) - Relevance for Nickel Exploration

    Czech Academy of Sciences Publication Activity Database

    Hora, Z. D.; Langrová, Anna; Pivec, E.

    2011-01-01

    Roč. 2010, 2011-1 (2011), s. 31-35 ISSN 0381-243X Institutional research plan: CEZ:AV0Z30130516 Keywords : Cassiar deposit * MINFILE 104P 005 * chrysolite asbestos * Cr-magnetite * nickel * Ni * heazlewoodite * serpentinization products * nickel minerals * awaruite Subject RIV: DB - Geology ; Mineralogy http://www.em.gov.bc.ca/Mining/Geoscience/PublicationsCatalogue/Fieldwork/Documents/2010/03_Hora_2010.pdf

  9. Cosmogenic 10Be Dating of Northern Quebec-Labrador Glacial Lake Shorelines and Drainage Deposits: Implications for the Final Meltwater Discharges of the Last Deglaciation

    Science.gov (United States)

    Roy, M.; Dube-Loubert, H.; Schaefer, J. M.; Hébert, S.

    2017-12-01

    The decay of the Laurentide ice sheet played an important role in the climate variability of the last deglaciation, notably through large discharges of meltwater from glacial lakes that disturbed the Atlantic meridional overturning oceanic circulation (AMOC). These former climate-forcing events are now under focus due to growing evidence showing that the present-day increase in freshwater releases from Greenland and other Arctic glaciers may potentially lead to a slowdown of the AMOC and cause important climate feedbacks. In northern Quebec and Labrador, the end of the deglaciation led to the formation of at least 10 important glacial lakes that drained into the nearby Labrador Sea where repeated meltwater discharges could have destabilized the ocean surface conditions in this key sector of the North Atlantic Ocean. Although the drainage of these ice-dammed lakes may form a good analogue for modern processes, the lack of direct constraints on the physiographic configuration and temporal evolution of these lakes limits our understanding of the timing and climate impact of these final meltwater pulses. Here we applied cosmogenic 10Be dating to raised boulder shorelines belonging to Lake Naskaupi, one of the largest glacial lakes in northern Quebec and Labrador. We reconstructed the lake extent and meltwater volume, as well as its lake-level history by systematic mapping of geomorphic features. We sampled a total of 16 boulders at 4 sites along the valley. In addition, we dated five boulders belonging to a large-scale outburst flood deposit recording the abrupt drainage of the lake. The distribution of the 21 ages shows a remarkable consistency, yielding a mean age of 7.8 ± 0.4 ka (1 outlier excluded). The ages from the shorelines are indistinguishable from those of the outburst flood deposit, suggesting that Lake Naskaupi existed for a relatively short time span. These new chronological data constrain the timing of the lake development and attendant drainage

  10. Plasticity in feeding selectivity and trophic structure of kelp forest associated fishes from northern Chile Plasticidad en la selección de alimento y estructura trófica de los peces asociados a bosques de macroalgas pardas del norte de Chile

    Directory of Open Access Journals (Sweden)

    ALEJANDRO PÉREZ-MATUS

    2012-03-01

    Full Text Available One of the primary ways in which species interact with their environment is through foraging; thereby directly consuming some fraction of their surrounding habitat. The habitat itself, in turn, may dictate the types of foraging opportunities that are available to the inhabitants. To investigate the relationship between habitat availability and diet composition of habitat-associated fishes, we estimated the relative abundance of the potential sessile and mobile prey items and the diet of the fish species assemblage associated to kelp forest. Specifically, diet and feeding selectivity of the kelp-forest associated fish assemblage were determined by calculating Manly's alpha selectivity index. We determined the diet of kelp forest associated fishes and their foraging behavior by comparing prey availability with those items present in the stomachs of fishes captured by gill net and spear gun. We calculated the degree of dietary overlap among fishes from four locations along the northern coast of Chile. Results indicate that utilization of prey by predators is predominantly affected by potential prey availability. With the exception of the two carnivorous species such as Pinguipes chilensis (Valenciennes, 1883 and Paralabrax humeralis (Cuvier & Valenciennes, 1828, whose diet did not change among sites, all other kelp-associated fishes changed their dietary habitats to consistent with the availability of local resources. Benthic resources changed among the different study sites, which led to differing diets even in the same species from different locations. Eleven of the 12 kelp forest fishes also showed some selectively for benthic prey. We conclude that the ability of fishes to be plastic in their feeding preference and, therefore, partition the benthic resources may set adaptations to co-exist in a dynamic environment such as kelp forest.Una de las principales formas en que las especies interactúan con su medio ambiente es a través de la

  11. Evaluación de metales redox-sensitivos como proxies de paleoxigenación en un ambiente marino hipóxico del norte de Chile Redox-sensitive metals evaluation as proxis of paleoxygenation in a hypoxic marine environment of northern Chile

    Directory of Open Access Journals (Sweden)

    JORGE VALDÉS

    2004-03-01

    metales registrada entre las muestras de la parte superior de los testigos (correspondientes a antes de 1996 y las muestras superficiales (correspondientes al año 2000 y tomadas en la misma zona de los testigos, pueden ser atribuidas al efecto de El Niño 1997-1998, el cual provocó un brusco descenso en el flujo de metales (principalmente Ni y Cd hacia los sedimentos, debido a una condición más oxigenada de la columna de agua. Este trabajo muestra que de los cinco metales analizados, solo en Ni y el Cd parecen tener un potencial como indicadores de paleoxigenación en la bahía Mejillones. Sin embargo, su uso está restringido para identificar cambios extremos desde una condición anóxica a una óxica en los sedimentos de fondo de esta bahía.The distribution of molybdenum, cadmium, zinc, vanadium and nickel, all redox-sensitive metals, was analyzed under a spatial (surface sediment samples and temporal (core samples perspective, in order to identify the potential of these metals for paleoxygenation interpretations in Mejillones bay, a hypoxic environment of northern Chile. Lithogenic supply (according to aluminum was discarded. Biogenic flux is not the unique factor that controls the mechanism of metals preservation in sediments of this bay. Spatial variation of metals concentration was investigated in relation to the bottom water oxygenation in each sampling station. Results showed that only Ni and Cd present a strong correlation with dissolved oxygen, increasing their concentration toward the deepest area of the bay were an oxygen minimum zone prevails with values around 0.02 mL L-1. The temporal variation in redox-sensitive metals, recorded in three sediments core covering the last 2,000 years, showed that bottom oxygenation of the bay changed from a more oxygenated environment in the past to a less oxygenated environment at present. A biogenic flux across a very well developed oxycline, associated to an anoxic sediment-water interface, are proposed to be the

  12. Spatial and temporal variability of 7Be and 210Pb wet deposition during four successive monsoon storms in a catchment of northern Laos

    International Nuclear Information System (INIS)

    Gourdin, E.; Evrard, O.; Huon, S.; Reyss, J.-L.; Ribolzi, O.; Bariac, T.; Sengtaheuanghoung, O.; Ayrault, S.

    2014-01-01

    Fallout radionuclides 7 Be and 210 Pb have been identified as potentially relevant temporal tracers for studying soil particles dynamics (surface vs. subsurface sources contribution; remobilization of in-channel sediment) during erosive events in river catchments. An increasing number of studies compared 7 Be: 210 Pb activity ratio in rainwater and sediment to estimate percentages of freshly eroded particles. However, the lack of data regarding the spatial and temporal variability of radionuclide wet deposition during individual storms has been identified as one of the main gaps in these estimates. In order to determine these key parameters, rainwater samples were collected at three stations during four storms that occurred at the beginning of the monsoon (June 2013) in the Houay Xon mountainous catchment in northern Laos. Rainwater 7 Be and 210 Pb activities measured using very low background hyperpure Germanium detectors ranged from 0.05 to 1.72 Bq L −1 and 0.02 to 0.26 Bq L −1 , respectively. Water δ 18 O were determined on the same samples. Total rainfall amount of the four sampled storms ranged from 4.8 to 26.4 mm (51 mm in total) at the time-fractionated collection point. Corresponding cumulative 7 Be and 210 Pb wet depositions during the sampling period were 17.6 and 2.9 Bq m −2 , respectively. The 7 Be: 210 Pb activity ratio varied (1) in space from 6 to 9 for daily deposition and (2) in time from 3 to 12 for samples successively collected. Intra-event evolution of rainwater 7 Be and 210 Pb activities as well as δ 18 O highlighted the progressive depletion of local infra-cloud atmosphere radionuclide stock with time (washout), which remains consistent with a Raleigh-type distillation process for water vapour. Intra-storm ratio increasing with time showed the increasing contribution of rainout scavenging. Implications of such variability for soil particle labelling and erosion studies are briefly discussed and recommendations are formulated for the

  13. The concentration, source and deposition flux of ammonium and nitrate in atmospheric particles during dust events at a coastal site in northern China

    Science.gov (United States)

    Qi, Jianhua; Liu, Xiaohuan; Yao, Xiaohong; Zhang, Ruifeng; Chen, Xiaojing; Lin, Xuehui; Gao, Huiwang; Liu, Ruhai

    2018-01-01

    Asian dust has been reported to carry anthropogenic reactive nitrogen during transport from source areas to the oceans. In this study, we attempted to characterize NH4+ and NO3- in atmospheric particles collected at a coastal site in northern China during spring dust events from 2008 to 2011. Based on the mass concentrations of NH4+ and NO3- in each total suspended particle (TSP) sample, the samples can be classified into increasing or decreasing types. In Category 1, the concentrations of NH4+ and NO3- were 20-440 % higher in dust day samples relative to samples collected immediately before or after a dust event. These concentrations decreased by 10-75 % in the dust day samples in Categories 2 and 3. Back trajectory analysis suggested that multiple factors, such as the transport distance prior to the reception site, the mixing layer depth on the transport route and the residence time across highly polluted regions, might affect the concentrations of NH4+ and NO3-. NH4+ in the dust day samples was likely either in the form of ammonium salts existing separately to dust aerosols or as the residual of incomplete reactions between ammonium salts and carbonate salts. NO3- in the dust day samples was attributed to various formation processes during the long-range transport. The positive matrix factorization (PMF) receptor model results showed that the contribution of soil dust increased from 23 to 36 % on dust days, with decreasing contributions from local anthropogenic inputs and associated secondary aerosols. The estimated deposition flux of NNH4++NO3- varied greatly from event to event; e.g., the dry deposition flux of NNH4++NO3- increased by 9-285 % in Category 1 but decreased by 46-73 % in Category 2. In Category 3, the average dry deposition fluxes of particulate nitrate and ammonium decreased by 46 % and increased by 10 %, respectively, leading to 11-48 % decrease in the fluxes of NNH4++NO3-.

  14. Effects of sand burial on dew deposition on moss soil crust in a revegetated area of the Tennger Desert, Northern China

    Science.gov (United States)

    Jia, Rong-liang; Li, Xin-rong; Liu, Li-chao; Pan, Yan-xia; Gao, Yan-hong; Wei, Yong-ping

    2014-11-01

    Sand burial and dew deposition are two fundamental phenomena profoundly influencing biological soil crusts in desert areas. However, little information is available regarding the effects of sand burial on dew deposition on biological soil crusts in desert ecosystems. In this study, we evaluated the effects of sand burial at depths of 0 (control), 0.5, 1, 2 and 4 mm on dew formation and evaporation of three dominant moss crusts in a revegetated area of the Tengger Desert (Northern China) in 2010. The results revealed that sand burial significantly decreased the amount of dew deposited on the three moss crust types by acting as a semi-insulator retarding the dew formation and evaporation rates. The changes in surface temperature cannot fully explain the variations of the formation and evaporation rates of dew by moss crusts buried by sand. The extension of dew retention time was reflected by the higher dew ratios (the ratio of dew amount at a certain time to the maximum value in a daily course) in the daytime, and may to some extent have acted as compensatory mechanisms that diminished the negative effects of the reduction of dew amount induced by sand burial of moss crusts. The resistances to reduction of dewfall caused by sand burial among the three moss crusts were also compared and it was found that Bryum argenteum crust showed the highest tolerance, followed by crusts dominated by Didymodon vinealis and Syntrichia caninervis. This sequence corresponds well with the successional order of the three moss crusts in the revegetated area, thereby suggesting that resistance to reduction of dewfall may act as one mechanism by which sand burial drives the succession of moss crusts in desert ecosystems. This side effect of dew reduction induced by sand burial on biological soil crusts should be considered in future ecosystem construction and management of desert area.

  15. 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.

  16. 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...

  17. Re-evaluation of the petrogenesis of the Proterozoic Jabiluka unconformity-related uranium deposit, Northern Territory, Australia

    Science.gov (United States)

    Polito, Paul A.; Kurt Kyser, T.; Thomas, David; Marlatt, Jim; Drever, Garth

    2005-11-01

    The world class Jabiluka unconformity-related uranium deposit in the Alligator Rivers Uranium Field, Australia, contains >163,000 tons of contained U3O8. Mineralization is hosted by shallow-to-steeply dipping basement rocks comprising graphitic units of chlorite-biotite-muscovite schist. These rocks are overlain by flat-lying coarse-grained sandstones belonging to the Kombolgie Subgroup. The deposit was discovered in 1971, but has never been mined. The construction of an 1,150 m decline into the upper eastern sector of the Jabiluka II deposit combined with closely spaced underground drilling in 1998 and 1999 allowed mapping and sampling from underground for the first time. Structural mapping, drill core logging and petrographic studies on polished thin sections established a detailed paragenesis that provided the framework for subsequent electron microprobe and X-ray diffraction, fluid inclusion, and O-H, U-Pb and 40Ar/39Ar isotope analysis. Uranium mineralization is structurally controlled within semi-brittle shears that are sub-conformable to the basement stratigraphy, and breccias that are developed within the hinge zone of fault-related folds adjacent to the shears. Uraninite is intimately associated with chlorite, sericite, hematite ± quartz. Electron microprobe and X-ray diffraction analysis of syn-ore illite and chlorite indicates a mineralization temperature of 200°C. Pre- and syn-ore minerals extracted from the Kombolgie Subgroup overlying the deposit and syn-ore alteration minerals in the Cahill Formation have δ18Ofluid and δ D fluid values of 4.0±3.7 and -27±17‰, respectively. These values are indistinguishable from illite separates extracted from diagenetic aquifers in the Kombolgie Subgroup up to 70 km to the south and east of the deposit and believed to be the source of the uraniferous fluid. New fluid inclusion microthermometry data reveal that the mineralising brine was saline, but not saturated. U-Pb and 207Pb/206Pb ratios of uraninite by

  18. Modern processes of palynomorph deposition at lakes of the northern region of the Rio de Janeiro State, Brazil

    Directory of Open Access Journals (Sweden)

    Cynthia F.P. da Luz

    2010-09-01

    Full Text Available Palynological analysis of pollen, Pteridophyta spores and algae deposited in the superficial sediments at Lagoa de Cima and Lagoa do Campelo Lakes, located in the north of Rio de Janeiro state, was used to determine the spatial variation of the palynomorphs deposition. A total of 67 pollen types were identified at Lagoa de Cima, with an expressive contribution of regional arboreous taxa, hydrophytes and ruderal plants of the pastureland. The depositional pattern of palynomorphs depends on the fluvial leakage, the proximity of the local sedimentation to the inlet of the Imbé and Urubu Rivers and the bathymetry of lake bottom. The highest concentrations of palynomorphs were observed in the decentralized and less deeper area, without the interference of the northeastern wind. At Lagoa do Campelo, a total of 58 pollen types were identified, among which the majority of the pollen grains came from hydrophytes, with the highest concentrations found along the northeastern shore. The southeastern shore showed high percentages of pollen and spores with degraded exine and mechanical damage, due to the transport through the lakeby the currents caused by the wind, confirmed by the depositional trend of damaged palinomorphs along the same direction as the prevailing winds.A análise palinológica de grãos de pólen, esporos de Pteridophyta e algas depositados nos sedimentos superficiais da Lagoa de Cima e Lagoa do Campelo, norte do Rio de Janeiro, foi usada para a avaliação da variação espacial de deposição dos palinomorfos. Um total de 67 tipos polínicos foi identificado na Lagoa de Cima, com expressiva contribuição de taxons arbóreos regionais, plantas hidrófitas e ruderais de pastagens. O padrão deposicional dos palinomorfos está sujeito às vazões fluviais, à proximidade do local de sedimentação em relação à desembocadura dos rios Imbé e Urubu e à batimetria do leito da lagoa. As maiores concentrações de palinomorfos foram

  19. Geochronological and thermochronological constraints on porphyry copper mineralization in the Domeyko alteration zone, northern Chile Determinaciones geocronológicas y termocronológicas para la mineralización de cobre porfídico en la zona de alteración de Domeyko, norte de Chile

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    Víctor Maksaev

    2010-01-01

    Full Text Available At Domeyko, 40 km south of Vallenar in northern Chile (28°57'S-70°53'W, the Dos Amigos and Tricolor porphyry copper centers are located within a north-south-elongated hydrothermal alteration zone 6x1.5 km of surface dimensions. The centers are related to tonalite to granodiorite porphyry stocks displaying potassic alteration, which are surrounded by Lower Cretaceous andesitic volcanic rocks with sericitic, kaolinite-illite and propylitic alteration zones. The western boundary of the alteration zone is marked by the post-mineralization Cachiyuyo Batholith of granodioritic to dioritic composition. U-Pb zircon ages for the Dos Amigos porphyry are of 106.Ü3.5 and 104.0±3.5 Ma; and 108.5±3.4 for the nearby Tricolor porphyry. The Cachiyuyo Batholith yielded U-Pb zircon ages of 99.6±1.8 and 99.1±1.9 Ma; and 40Ar/39Ar ages for biotite of 96.9±3.9 and 94.8±0.9 Ma. These dates indicate that batholith emplacement postdated the Dos Amigos and Tricolor porphyries, in agreement with geological relationships. Although copper mineralization is spatially and genetically related to the Lower Cretaceous (Albian porphyry stocks, most of the dated hydrothermal micas from the Dos Amigos and Tricolor porphyries yielded 40Ar/39Ar ages between 97.1±2.5 and 96.0±1.4 Ma, which overlap within error with the cooling ages obtained for the neighboring batholith. 40Ar/39Ar dating of micas revealed significant disturbance of their K-Ar isotopic systematics that complicates accurate determination of the timing of hydrothermal activity at Domeyko. Nevertheless, the 40Ar/39Ar data establish a minimum Late Cretaceous age for this activity. A fission track age of 59.8±9.8 Ma of apatite from the Dos Amigos porphyry indicates cooling through the temperature range of the apatite partial annealing zone (~125-60°C during the Paleocene; and an (U-Th/He age of 44.7±3.7 Ma of apatite from the same porphyry sample shows cooling through the temperature range of the apatite He

  20. Atmospheric heavy metal deposition in Northern Vietnam: Hanoi and Thainguyen case study using the moss biomonitoring technique, INAA and AAS.

    Science.gov (United States)

    Viet, Hung Nguyen; Frontasyeva, Marina Vladimirovna; Thi, Thu My Trinh; Gilbert, Daniel; Bernard, Nadine

    2010-06-01

    The moss technique is widely used to monitor atmospheric deposition of heavy metals in many countries in Europe, whereas this technique is scarcely used in Asia. To implement this international reliable and cheap methodology in the Asian countries, it is necessary to find proper moss types typical for the Asian environment and suitable for the biomonitoring purposes. Such a case study was undertaken in Vietnam for assessing the environmental situation in strongly contaminated areas using local species of moss Barbula indica. The study is focused on two areas characterized by different pollution sources: the Hanoi urban area and the Thainguyen metallurgical zone. Fifty-four moss samples were collected there according to standard sampling procedure adopted in Europe. Two complementary analytical techniques, atomic absorption spectrometry (AAS) and instrumental neutron activation analysis (INAA), were used for determination of elemental concentrations in moss samples. To characterize the pollution sources, multivariate statistical analysis was applied. A total of 38 metal elements were determined in the moss by the two analytical techniques. The results of descriptive statistics of metal concentration in moss from the city center and periphery of Hanoi determined by AAS are presented. The similar results for moss from Thainguyen province determined by INAA and AAS are given also. A comparison of mean elemental concentrations in moss of this work with those in different environmental conditions of other authors provides reasonable information on heavy metal atmospheric deposition levels. Factor loadings and factor scores were used to identify and apportion contamination sources at the sampling sites. The values of percentage of total of factors show two highly different types of pollution in the two examined areas-the Hanoi pollution composition with high portion of urban-traffic activity and soil dust (62%), and the one of Thainguyen with factors related to industrial

  1. Morphosedimentary and hydrographic features of the northern Argentine margin: The interplay between erosive, depositional and gravitational processes and its conceptual implications

    Science.gov (United States)

    Preu, Benedict; Hernández-Molina, F. Javier; Violante, Roberto; Piola, Alberto R.; Paterlini, C. Marcelo; Schwenk, Tilmann; Voigt, Ines; Krastel, Sebastian; Spiess, Volkhard

    2013-05-01

    Bottom currents and their margin-shaping character became a central aspect in the research field of sediment dynamics and paleoceanography during the last decades due to their potential to form large contourite depositional systems (CDS), consisting of both erosive and depositional features. A major CDS at the northern Argentine continental margin was studied off the Rio de la Plata River by means of seismo- and hydro-acoustic methods including conventional and high-resolution seismic, parametric echosounder and single and swath bathymetry. Additionally, hydrographic data were considered allowing jointly interpretation of morphosedimentary features and the oceanographic framework, which is dominated by the presence of the dynamic and highly variable Brazil-Malvinas Confluence. We focus on three regional contouritic terraces identified on the slope in the vicinity of the Mar del Plata Canyon. The shallowest one, the La Plata Terrace (˜500 m), is located at the Brazil Current/Antarctic Intermediate Water interface characterized by its deep and distinct thermocline. In ˜1200 m water depth the Ewing Terrace correlates with the Antarctic Intermediate Water/Upper Circumpolar Deep Water interface. At the foot of the slope in ˜3500 m the Necochea Terrace marks the transition between Lower Circumpolar Deep Water and Antarctic Bottom Water during glacial times. Based on these correlations, a comprehensive conceptual model is proposed, in which the onset and evolution of contourite terraces is controlled by short- and long-term variations of water mass interfaces. We suggest that the terrace genesis is strongly connected to the turbulent current pattern typical for water mass interfaces. Furthermore, the erosive processes necessary for terrace formation are probably enhanced due to internal waves, which are generated along strong density gradients typical for water mass interfaces. The terraces widen through time due to locally focused, partly helical currents along the

  2. Sources of Matter and Ore-Producing Fluid of the Tamunyer Gold-Sulfide Deposit (Northern Urals): Isotope Results

    Science.gov (United States)

    Zamyatina, D. A.; Murzin, V. V.

    2018-02-01

    The Tamunyer deposit is a typical example of gold-sulfide mineralization located in the lower lithologic-stratigraphic unit (S2-D1) of the Auerbach volcanic-plutonic belt. The latter comprises island-arc andesitic volcano-sediments, volcanics, and comagmatic intrusive formations. Carbonates have demonstrated intermediate values of δ13C between marine limestone and mantle. The quartz δ18O is in the range of 15.3-17.2‰. The δ34S of sulfides from the beresitized volcano-sedimentary rocks and ores varies widely from -7.5 to 12‰. The calculated isotope compositions of H2O, CO2, and H2S of the ore-bearing fluid imply two major sources of matter contributing to ore genesis: local rocks and foreign fluid. The ore-bearing fluid was formed by interaction and isotope equilibration between a deep magmatic fluid and marine carbonates (W/R 1), with the contribution of sulfur from the volcano-sedimentary rocks.

  3. Integration of 2D and 3D reflection seismic data with deep boreholes in the Kevitsa Ni-Cu-PGE deposit, northern Finland

    Science.gov (United States)

    Koivisto, Emilia; Malehmir, Alireza; Voipio, Teemu; Wijns, Chris

    2013-04-01

    Kevitsa is a large disseminated sulphide Ni-Cu-PGE deposit hosted by the Kevitsa mafic-ultramafic intrusion in northern Finland and dated as about 2.06 Ga old. The Geological Survey of Finland first discovered the Kevitsa deposit in 1987. Open pit mining by Kevitsa Mining Oy/First Quantum Minerals Ltd. commenced in June 2012. The final pit depth is planned to be 550-600 m. The estimated ore reserves of the Kevitsa intrusion are about 240 million tones (using a nickel cut-off grade of 0.1%). The expected life-of-mine is 20-30 years. More than 400 hundred holes have been drilled in the Kevitsa area, but most are concentrated close to the known deposit and do not provide a comprehensive understanding of the extent of the intrusion. The basal contact of the intrusion is penetrated by only about 30 drill holes, most of which are shallow. A better knowledge of the geometry of the intrusion would provide a framework for near-mine and deep exploration in the area. An exact knowledge on the basal contact of the intrusion would also provide an exploration target for the contact-type mineralization that is often more massive and richer in Ni-Cu. In December 2007, a series of 2D reflection seismic profiles was acquired in the Kevitsa area. It consisted of four connected survey lines between 6 and 11 km long. In 2010, the initial positive results of the 2D seismic survey led Kevitsa Mining Oy/First Quantum Minerals Ltd. to initiate a 3D reflection seismic survey. The 3D seismic survey is limited to the closer vicinity of the known deposit, while the 2D seismic survey was designed to provide a more regional view of the Kevitsa intrusive complex. The main aims of the 2D and 3D seismic surveys were to delineate the shape and extent of the ore-bearing Kevitsa intrusion and the geometry of some of the host rock and surrounding units, and extract information about the larger-scale structures and structures important for mine-planning purposes. The 2D and 3D seismic data were used to

  4. Origin and tectonic implications of the Zhaxikang Pb-Zn-Sb-Ag deposit in northern Himalaya: evidence from structures, Re-Os-Pb-S isotopes, and fluid inclusions

    Science.gov (United States)

    Zhou, Qing; Li, Wenchang; Qing, Chengshi; Lai, Yang; Li, Yingxu; Liao, Zhenwen; Wu, Jianyang; Wang, Shengwei; Dong, Lei; Tian, Enyuan

    2018-04-01

    The Zhaxikang Pb-Zn-Sb-Ag-(Au) deposits, located in the eastern part of northern Himalaya, totally contain more than 1.146 million tonnes (Mt) of Pb, 1.407 Mt of Zn, 0.345 Mt of Sb, and 3 kilotonnes (kt) of Ag. Our field observations suggest that these deposits are controlled by N-S trending and west- and steep-dipping normal faults, suggesting a hydrothermal rather than a syngenetic sedimentary origin. The Pb-Zn-Sb-Ag-(Cu-Au) mineralization formed in the Eocene as indicated by a Re-Os isochron age of 43.1 ± 2.5 Ma. Sulfide minerals have varying initial Pb isotopic compositions, with (206Pb/204Pb)i of 19.04-19.68, (207Pb/204Pb)i of 15.75-15.88, and (208Pb/204Pb)i of 39.66-40.31. Sulfur isotopic values display a narrow δ34S interval of +7.8-+12.2‰. These Pb-S isotopic data suggest that the Zhaxikang sources of Pb and S should be mainly from the coeval felsic magmas and partly from the surrounding Mesozoic strata including metasedimentary rocks and layered felsic volcanic rocks. Fluid inclusion studies indicate that the hydrothermal fluids have medium temperatures (200-336 °C) but varying salinities (1.40-18.25 wt.% NaCl equiv.) with densities of 0.75-0.95 g/cm3, possibly suggesting an evolution mixing between a high salinity fluid, perhaps of magmatic origin, with meteoric water.

  5. 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

  6. Changes in tree species richness, stand structure and soil properties in a successional chronosequence in northern Chiloé Island, Chile Cambios en la riqueza de especies arbóreas, estructura de rodales y propiedades del suelo en una cronosecuencia sucesional en el norte de la Isla de Chiloé, Chile

    Directory of Open Access Journals (Sweden)

    JUAN C. ARAVENA

    2002-06-01

    Full Text Available We studied a chronosequence of forest fragments in northern Chiloé Island, southern Chile, with the aim of assessing ecosystem recovery patterns following anthropogenic disturbance. Hypotheses regarding successional trends in tree species richness, the replacement of shade-intolerant by shade-tolerant species, and the impact of disturbance on soil properties were evaluated in nine forest stands. The chronosequence encompassed two early (minimum stand age Estudiamos una cronosecuencia de bosques sucesionales en el norte de la Isla de Chiloé, con el objeto de determinar sus patrones de recuperación luego de perturbación antrópica. Se evaluaron hipótesis referentes a las tendencias de cambio en la riqueza de especies arbóreas a lo largo de la sucesión, el reemplazo de especies sombra intolerantes por especies sombra tolerantes, y el impacto de la perturbación en las propiedades edáficas de estos fragmentos. Muestreamos nueve rodales, representados por dos bosques sucesionales tempranos (<15 años de edad mínima del rodal, tres rodales intermedios (30-60 años, tres avanzados (129-134 años, y un bosque antiguo (ca. 200 años. Las edades mínimas fueron estimadas a través de muestras de incremento radial de al menos 30 árboles del dosel por rodal. Los rodales tempranos e intermedios mostraron evidencias de perturbación por incendios moderados, con unos pocos grandes árboles vivos remanentes. En cada rodal se establecieron parcelas permanentes de 50 x 20 m para determinar densidades y áreas basales de árboles, con subparcelas interiores para estimar densidades de brinzales y plántulas. Para caracterizar los procesos edáficos en los rodales se determinó el pH del suelo, los contenidos totales de carbono (C y nitrógeno (N, N disponible y densidad aparente. En contraste con la hipótesis que predice una disminución de la riqueza de especies arbóreas en rodales más antiguos, debido a la exclusión de especies pioneras, la riqueza

  7. Outcrop analogue study of Permocarboniferous geothermal sandstone reservoir formations (northern Upper Rhine Graben, Germany): impact of mineral content, depositional environment and diagenesis on petrophysical properties

    Science.gov (United States)

    Aretz, Achim; Bär, Kristian; Götz, Annette E.; Sass, Ingo

    2016-07-01

    The Permocarboniferous siliciclastic formations represent the largest hydrothermal reservoir in the northern Upper Rhine Graben in SW Germany and have so far been investigated in large-scale studies only. The Cenozoic Upper Rhine Graben crosses the Permocarboniferous Saar-Nahe Basin, a Variscan intramontane molasse basin. Due to the subsidence in this graben structure, the top of the up to 2-km-thick Permocarboniferous is located at a depth of 600-2900 m and is overlain by Tertiary and Quaternary sediments. At this depth, the reservoir temperatures exceed 150 °C, which are sufficient for geothermal electricity generation with binary power plants. To further assess the potential of this geothermal reservoir, detailed information on thermophysical and hydraulic properties of the different lithostratigraphical units and their depositional environment is essential. Here, we present an integrated study of outcrop analogues and drill core material. In total, 850 outcrop samples were analyzed, measuring porosity, permeability, thermal conductivity and thermal diffusivity. Furthermore, 62 plugs were taken from drillings that encountered or intersected the Permocarboniferous at depths between 1800 and 2900 m. Petrographic analysis of 155 thin sections of outcrop samples and samples taken from reservoir depth was conducted to quantify the mineral composition, sorting and rounding of grains and the kind of cementation. Its influence on porosity, permeability, the degree of compaction and illitization was quantified. Three parameters influencing the reservoir properties of the Permocarboniferous were detected. The strongest and most destructive influence on reservoir quality is related to late diagenetic processes. An illitic and kaolinitic cementation and impregnation of bitumina document CO2- and CH4-rich acidic pore water conditions, which are interpreted as fluids that migrated along a hydraulic contact from an underlying Carboniferous hydrocarbon source rock. Migrating

  8. Biología poblacional de huirales submareales de Macrocystis integrifolia y Lessonia trabeculata (Laminariales, Phaeophyceae en un ecosistema de surgencia del norte de Chile: variabilidad interanual y El Niño 1997-1998 Population biology of the subtidal kelps Macrocystis integrifolia and Lessonia trabeculata (Laminariales, Phaeophyceae in an upwelling ecosystem of northern Chile: interannual variability and El Niño 1997-1998

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    J.M. ALONSO VEGA

    2005-03-01

    Full Text Available This paper describes the population biology of Lessonia trabeculata and Macrocystis integrifolia during and after the 1997-1998 El Niño in an area of permanent coastal upwelling in northern Chile. Spatial and temporal patterns of distribution were evaluated seasonally for adult and juvenile sporophytes of both species between 1996 and 2003. These two kelp form an assemblage distributed between 2 and 15 m depth, with disjunct patterns along a bathymetric gradient, including two morphs of L. trabeculata, the occurrence of which depends on the presence or absence of M. integrifolia. During the 1997-1998 El Niño the spatial-temporal patterns of abundance of the kelp assemblage were maintained by the continuity of coastal upwelling, which buffered and moderated superficial warming of the sea and depletion of nutrients. In this context, localities associated with coastal upwelling areas could function as "sources" of reproductive propagules after passage of El Niño, thus increasing kelp recolonization rates in "sink" localities, which suffered local kelp extinctions. Intensification of upwelling processes after the 1998-2000 La Niña increased nutrient inputs into subtidal habitats, favoring the productivity of the kelp assemblage. However, an abrupt change in the spatial-temporal patterns of abundance of the black sea urchin Tetrapygus niger, the most conspicuous benthic grazer in northern Chile, produced local extinctions of M. integrifolia and compression of the range of bathymetric distribution of L. trabeculata. Top-down (mortality of benthic carnivores during the 1997-1998 El Niño and bottom-up effects (intensity and frequency of upwelling in this subtidal coastal ecosystem appear to regulate the kelp-herbivore interactions in the study area. The main sources of reproductive propagules for the re-establishment of the assemblage kelp were fertile sporophytes which included isolated, low density patches of M.integrifolia located within the bed

  9. Tsygankoite, Mn8Tl8Hg2(Sb21Pb2TlΣ24S48, a New Sulfosalt from the Vorontsovskoe Gold Deposit, Northern Urals, Russia

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    Anatoly V. Kasatkin

    2018-05-01

    Full Text Available Tsygankoite, ideally Mn8Tl8Hg2(Sb21Pb2TlΣ24S48, is a new sulfosalt discovered at the Vorontsovskoe gold deposit, Northern Urals, Russia. It occurs as lath-like elongated crystals up to 0.2 mm embedded in calcite–dolomite–clinochlore matrix. The associated minerals also include aktashite, alabandite, arsenopyrite, barite, cinnabar, fluorapatite, orpiment, pyrite, realgar, routhierite, sphalerite, tilasite, and titanite. The new mineral is non-fluorescent, black, and opaque with a metallic lustre and black streak. It is brittle with an uneven fracture and no obvious parting and cleavage. Its Vickers hardness (VHN10 is 144 kg/mm2 (range 131–167 kg/mm2 and its calculated density is 5.450 g cm. In reflected light, tsygankoite is white; between crossed polars it is dark grey to black. It is strongly anisotropic: rotation tints vary from light grey to dark grey to black. Pleochroism and internal reflections are not observed. The chemical composition of tsygankoite (wt %, electron-microprobe data is: Mn 6.29, Hg 5.42, Tl 26.05, Pb 5.84, As 3.39, Sb 30.89, S 21.87, total 99.75. The empirical formula, calculated on the basis of 90 atoms pfu, is: Mn8.06Tl8.00Hg1.90(Sb17.87As3.19Pb1.99Tl0.97Σ24.02S48.03. Tsygankoite is monoclinic, space group C2/m, a = 21.362(4 Å, b = 3.8579(10 Å, c = 27.135(4 Å, β = 106.944(14°, V = 2139.19(17 Å3 and Z = 1. The five strongest diffraction peaks from X-ray powder pattern (listed as (d,Å(I(hkl are: 3.587(100(112, 3.353(70(−114, 3.204(88(405, 2.841(72(−513, and 2.786(99(−514. The crystal structure of tsygankoite was refined from single-crystal X-ray diffraction data to R = 0.0607 and consists of an alternation of two thick layer-like arrays, one based on PbS-archetype and the second on SnS-archetype. Tsygankoite has been approved by the IMA-CNMNC under the number 2017-088. It is named for Mikhail V. Tsyganko, a mineral collector from Severouralsk, Northern Urals, Russia, who collected the samples where the

  10. Evidence for large-magnitude, post-Eocene extension in the northern Shoshone Range, Nevada, and its implications for Carlin-type gold deposits in the lower plate of the Roberts Mountains allochthon

    Science.gov (United States)

    Colgan, Joseph P.; Henry, Christopher D.; John, David A.

    2014-01-01

    The northern Shoshone and Toiyabe Ranges in north-central Nevada expose numerous areas of mineralized Paleozoic rock, including major Carlin-type gold deposits at Pipeline and Cortez. Paleozoic rocks in these areas were previously interpreted to have undergone negligible postmineralization extension and tilting, but here we present new data that suggest major post-Eocene extension along west-dipping normal faults. Tertiary rocks in the northern Shoshone Range crop out in two W-NW–trending belts that locally overlie and intrude highly deformed Lower Paleozoic rocks of the Roberts Mountains allochthon. Tertiary exposures in the more extensive, northern belt were interpreted as subvertical breccia pipes (intrusions), but new field data indicate that these “pipes” consist of a 35.8 Ma densely welded dacitic ash flow tuff (informally named the tuff of Mount Lewis) interbedded with sandstones and coarse volcaniclastic deposits. Both tuff and sedimentary rocks strike N-S and dip 30° to 70° E; the steeply dipping compaction foliation in the tuffs was interpreted as subvertical flow foliation in breccia pipes. The southern belt along Mill Creek, previously mapped as undivided welded tuff, includes the tuff of Cove mine (34.4 Ma) and unit B of the Bates Mountain Tuff (30.6 Ma). These tuffs dip 30° to 50° east, suggesting that their west-dipping contacts with underlying Paleozoic rocks (previously mapped as depositional) are normal faults. Tertiary rocks in both belts were deposited on Paleozoic basement and none appear to be breccia pipes. We infer that their present east tilt is due to extension on west-dipping normal faults. Some of these faults may be the northern strands of middle Miocene (ca. 16 Ma) faults that cut and tilted the 34.0 Ma Caetano caldera ~40° east in the central Shoshone Range (

  11. El IDRC en Chile

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

    prácticas para promover la innovación ... Estudios para Latino américa sentaron las ... Argentina, Brasil, Canadá, Chile y Colombia. ... soluciones locales innovadoras y duraderas que apuntan a proporcionar opciones y cambios a aquellos ...

  12. The Mesozoic Caosiyao giant porphyry Mo deposit in Inner Mongolia, North China and Paleo-Pacific subduction-related magmatism in the northern North China Craton

    Science.gov (United States)

    Wu, Huaying; Zhang, Lianchang; Pirajno, Franco; Shu, Qihai; Zhang, Min; Zhu, Mingtian; Xiang, Peng

    2016-09-01

    The Caosiyao giant porphyry Mo deposit is located in the Wulanchabu area of Inner Mongolia, within the northern North China Craton (NCC). It contains more than 2385 Mt of ore with an average grade of 0.075% Mo. In the Caosiyao mining district, Mo mineralization occurs mainly in a Mesozoic granite porphyry as disseminations and stockworks, with some Mo distributed in Archean metamorphic rocks and diabase as stockworks and veins. The host granite porphyry is composed of two different phases that can be distinguished based on mineral assemblages and textures: one phase contains large and abundant phenocrysts (coarse-grained), while the other phase is characterized by fewer and smaller phenocrysts (medium-grained). Zircon U-Pb-Hf analyses of the former phase yielded a concordant 206Pb/238U age of 149.8 ± 2.4 Ma with a 206Pb/238U weighted mean age of 149.9 ± 2.4 Ma and εHf(t) values ranging from -12.2 to 18.3, while the latter phase gave a concordant 206Pb/238U age of 149.0 ± 2.2 Ma with a 206Pb/238U weighted mean age of 149.0 ± 2.1 Ma and εHf(t) values ranging from -13.1 to 17.7. Five samples of disseminated molybdenite have a 187Re-187Os isochron age of 149.5 ± 5.3 Ma with a weighted average age of 149.0 ± 1.8 Ma, whereas six veinlet-type molybdenite samples have a well-constrained 187Re-187Os isochron age of 146.9 ± 3.1 Ma and a weighted average age of 146.5 ± 0.8 Ma. Thus, it is suggested that the Mo mineralization of the Caosiyao deposit occurred during the Late Jurassic (ca. 147-149 Ma), almost coeval with the emplacement of the host granite porphyry (ca. 149-150 Ma). The host granite porphyry is characterized by high silica (SiO2 = 71.52-74.10 wt%), relatively high levels of oxidation (Fe2O3/FeO = 0.32-0.94 wt%) and high alkali element concentrations (Na2O + K2O = 8.21-8.76 wt%). The host granite porphyry also shows enrichments in U and K, and depletion in Ba, Sr, P, Eu, and Ti, suggesting strong fractional crystallization of plagioclase, biotite, and

  13. 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)

  14. Contenido de metales en Cancer polyodon (Crustacea: Decapoda en un sistema de bahías del norte de Chile (27°S Metal contents in Cancer polyodon (Crustacea: Decapoda in a bay system of northern Chile (27°S

    Directory of Open Access Journals (Sweden)

    Alexis Castillo

    2011-11-01

    Full Text Available El contenido de Zn, Cu, Cd, Pb, Fe, Al y Ni fue analizado en tejido muscular de Cancer polyodon en las bahías de Caldera, Calderilla, Inglesa y Salada (Atacama, Chile. Los resultados fueron comparados con estudios similares desarrollados por otros autores y la normativa de carácter nacional e internacional relacionada con el contenido de metales pesados en crustáceos para consumo humano. El orden de abundancia de los metales analizados en C. polyodon fue CdThe contents of Zn, Cu, Cd, Pb, Fe, Al and Ni in the muscle tissue of Cancer polyodon from Caldera, Calderilla, Inglesa, and Salada bays (Atacama, Chile were quantified. The results were compared with similar studies by other authors and with the national and international regulatory standards for heavy metal contents in crustaceans for human consumption. In increasing order, the metal contents in C. polyodon were: Cd< Ni< Cu< Pb< Zn

  15. 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.

  16. 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)

  17. Neogene basin infilling from cosmogenic nuclides (10Be and 21Ne) in Atacama, Chile

    Science.gov (United States)

    Sanchez, Caroline; Regard, Vincent; Carretier, Sébastien; Riquelme, Rodrigo; Blard, Pierre-Henri; Campos, Eduardo; Brichau, Stéphanie; Lupker, Marteen; Hérail, Gérard

    2017-04-01

    In the hyperarid Atacama Desert, northern Chile, Neogene sediments host copper rich layers (exotic supergene mineralization). Current mines are excavated into relatively thin (production (quickly decreasing with depth) and disintegration (not for 21Ne). Sampling depths are at ˜100 m and at ˜50 m below the desert surface. First, 21Ne gives lower boundaries for upstream erosion rates or local sedimentation rate. These bounds are between 2 and 10 m/Ma, which is quite important for the area. The ratio between the two cosmogenic nuclides indicate a maximum burial age of 12 Ma (minimal erosion rate of 15 m/Ma) and is surprisingly similar from bottom to top, indicating a probable rapid infilling. We finally processed a Monte-Carlo inversion. This inversion helps taking into account the post-deposition muonic production of cosmogenic nuclides. Inversion results is dependent on the muonic production scheme. Interestingly, the similarity in concentrations from bottom to top pleads for quite low production at depth. Our data finally indicates a quick infilling between 12.5 and 10 Ma BP accounting for ˜100 m of deposition (minimum sedimentation rate of 40 m/Ma).

  18. 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)

  19. 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...

  20. Chile rural electrification cooperation

    Energy Technology Data Exchange (ETDEWEB)

    Flowers, L. [National Renewable Energy Lab., Golden, CO (United States)

    1997-12-01

    The author describes a joint program to use renewables for rural electrification projects in Chile. The initial focus was in a limited part of the country, involving wind mapping, pilot project planning, training, and development of methodologies for comparative evaluations of resources. To this point three wind hybrid systems have been installed in one region, as a part of the regional private utility, and three additional projects are being designed. Additional resource assessment and training is ongoing. The author points out the difficulties in working with utilities, the importance of signed documentation, and the need to look at these programs as long term because of the time involved in introducing such new technologies.

  1. Phosphorus and uranium in fossils of Bahia Inglesa, Chile. Comparison with actual pieces

    International Nuclear Information System (INIS)

    Rojo L, M.

    1987-01-01

    In the phosphoric ore deposit of Bahia Inglesa, Chile, several fossils of selaqueous teeth and cetaceous bones have been recognized. Whales and sharks fossil and their present equivalent parts were submitted to chemical analysis and compared regarding some elements. A discussion about the deposit's origin, is presented. (M.C.K.)

  2. Forensic psychiatry in Chile.

    Science.gov (United States)

    St Denis, Emily E; Sepúlveda, Enrique; Téllez, Carlos; Arboleda-Flórez, Julio; Stuart, Heather; Lam, Miu

    2012-01-01

    Mental disorders are among the most prevalent of chronic disorders, and a high prevalence of these disorders has been consistently found in jails and prisons. This study was a retrospective case series that described the population of adults charged with a criminal offense who were court ordered to undergo a psychiatric assessment within the Medical Legal Service in Santiago, Chile from 2005 to 2006. Characteristics were explored in order to better understand this population in light of the recent reforms in the judicial and health systems of Chile. Ninety percent of sampled individuals were male, primarily between the ages of 18-39 years. Seventy percent of the evaluations came from the pre-reformed judicial system and 30% were from the reformed system. Approximately 63% of evaluated offenders were considered to have a psychiatric pathology, the most common being the personality disorders. Of the evaluated offenders, approximately 84% were considered by a psychiatrist to be criminally responsible for their crime, 7% were regarded as having diminished criminal responsibility, 4% were considered to be not criminally responsible for their crime, and 4% were cases where criminal responsibility was not applicable. Profession status, municipality of residence, type of residence, ICD-10 diagnosis, treatment recommendation, and criminal responsibility were found to be significantly different between male and female evaluated offenders. Results from this investigation will contribute to knowledge about forensic psychiatry and mental health in Latin America, and will hopefully pave the way for more research and international comparisons. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Robotics research in Chile

    Directory of Open Access Journals (Sweden)

    Javier Ruiz-del-Solar

    2016-12-01

    Full Text Available The development of research in robotics in a developing country is a challenging task. Factors such as low research funds, low trust from local companies and the government, and a small number of qualified researchers hinder the development of strong, local research groups. In this article, and as a case of study, we present our research group in robotics at the Advanced Mining Technology Center of the Universidad de Chile, and the way in which we have addressed these challenges. In 2008, we decided to focus our research efforts in mining, which is the main industry in Chile. We observed that this industry has needs in terms of safety, productivity, operational continuity, and environmental care. All these needs could be addressed with robotics and automation technology. In a first stage, we concentrate ourselves in building capabilities in field robotics, starting with the automation of a commercial vehicle. An important outcome of this project was the earn of the local mining industry confidence. Then, in a second stage started in 2012, we began working with the local mining industry in technological projects. In this article, we describe three of the technological projects that we have developed with industry support: (i an autonomous vehicle for mining environments without global positioning system coverage; (ii the inspection of the irrigation flow in heap leach piles using unmanned aerial vehicles and thermal cameras; and (iii an enhanced vision system for vehicle teleoperation in adverse climatic conditions.

  4. Recording of ocean-climate changes during the last 2,000 years in a hypoxic marine environment off northern Chile (23°S Registro de cambios océano-climáticos durante los últimos 2000 años en un ambiente marino hipóxico en el norte de Chile (23°S

    Directory of Open Access Journals (Sweden)

    LUC ORTLIEB

    2000-06-01

    Full Text Available Atmosphere-ocean interactions are particularly strong along the Chile-Peru coast and largely account for the extreme aridity of the Atacama Desert. Near the center of the driest part of this coastal desert, we found that the embayment Bahía Mejillones constitutes an unusually favorable setting for the formation and subsequent preservation of a sedimentary record of the successive oceanographic conditions of the last few thousand years. This work deals with relative abundance of various bio-indicators, including fish scales, foraminifers and phytoplankton, with a centimetre-scale resolution, in several gravity cores taken from 80 to 120 m depth, in a low-oxygen environment. We use this information to document ocean-climate changes at decadal to centennial time scales in the region. Radiocarbon dating on the bulk organic-rich sediment provides the chronological framework for the observed paleoceanographic changes. We interpret that an episode of relatively warmer water, with a stratified water column and enhanced anoxic ( 0.3 ml l-1 O2 conditions at the bottom of the water column, may correspond to the Little Ice Age (16th to mid-19th centuries. During the first millennium of our era, two thin sedimentary layers which present similarities with the bed assigned to the warm episode are interpreted as possible remnants of very strong, or " mega " El Niño events. The study confirms that Bahía Mejillones sediments did record ocean-climate changes with a very high time-resolution, and thus deserve a closer attention to investigate the ocean-atmosphere interactions over the last few thousand yearsLas interacciones océano-atmósfera son particularmente fuertes a lo largo de la costa de Chile y Perú y explican en gran parte la extrema aridez del desierto de Atacama. Cerca del sector más seco del desierto costero, hemos encontrado que la bahía semi-cerrada de Bahía Mejillones constituye un sitio particularmente favorable para la formación y

  5. Geological-geochemical characterization of the Semilus and upper Frasnian deposits of the northern part of the Timano-Pechorsk province. [USSR

    Energy Technology Data Exchange (ETDEWEB)

    Aminov, L.Z.; Peneva, A.Z.; Udot, V.F.

    1981-01-01

    A geochemical characterization of the semilux-upper-Frasnian sections of various Paleotectonic elements of the northern part of the Timano-Pechorsk province is presented. The distribution of oil and gas source rock is established and an assessment of the regions is given.

  6. 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

  7. 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.

  8. Climate change impacts on municipal, mining, and agricultural water supplies in Chile

    Science.gov (United States)

    Daniel G. Neary; Pablo Garcia-Chevesich

    2008-01-01

    Agricultural and municipal water supply interests in Chile rely heavily on streams which flow from the Andes Mountains. The highly productive Copiapo agricultural region, on the southern edge of the Atacama Desert, is a major supplier of fruit and other crops for the Northern American market during winter. This region relies entirely on snow and icemelt streams to...

  9. [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.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Zircon and cassiterite U-Pb ages, petrogeochemistry and metallogenesis of Sn deposits in the Sibao area, northern Guangxi: constraints on the neoproterozoic granitic magmatism and related Sn mineralization in the western Jiangnan Orogen, South China

    Science.gov (United States)

    Chen, Lei; Wang, Zongqi; Yan, Zhen; Gong, Jianghua; Ma, Shouxian

    2018-01-01

    A number of Sn deposits associated with Neoproterozoic granites are located in the western Jiangnan Orogen of northern Guangxi. The distribution of Sn mineralization is controlled by faults occurring within and around the Neoproterozoic granites. The hydrothermal alteration and mineralization of these Sn deposits exhibit zoning from the granite to the wall rock. The laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb ages of the cassiterite and zircon from ore-bearing granite in the Menggongshan Sn deposit are 829 ± 19 Ma and 822 ± 4 Ma, respectively, indicating that the Sn mineralization and granites formed in the Neoproterozoic and can considered to be products of coeval magmatic and hydrothermal activities. The ore-bearing granite and Neoproterozoic granites in northern Guangxi are high-K, calc-alkaline, peraluminous, S-type granites that are depleted in Nb, Ti, Sr and Ba and highly enriched in Rb, U and Pb. All the granites show steep fractionated light rare earth element (LREE) and flat heavy rare earth element (HREE) patterns, with strongly negative Eu anomalies. The ɛHf(t) values of the ore-bearing granite vary from - 9.0 to - 1.7, with an average value of - 4.1. Additionally, the ore-bearing granite exhibits low oxygen fugacity values. The magmatic source experienced partial melting during their evolution, and the source was dominated by recycled heterogeneous continental crustal materials. Our evidence confirms that the Neoproterozoic granites in northern Guangxi formed in a collisional tectonic setting. The collision between the Cathaysia and Yangtze blocks or between the Sibao arc (Jiangnan arc) and the Yangtze Block caused asthenospheric upwelling, leading to partial melting and recycling of the crust, forming the peraluminous S-type granites in the Neoproterozoic. The Sn mineralization has a close genetic relationship with the Neoproterozoic granite. The highly differentiated, peraluminous, B-enriched, crustally derived

  13. Variabilidad estacional de cadmio en un sistema de surgencia costera del norte de Chile (Bahía Mejillones del Sur, 23° S Seasonal variability of cadmium in a coastal upwelling system off northern Chile (Mejillones bay, 23° S

    Directory of Open Access Journals (Sweden)

    JORGE VALDÉS

    2006-12-01

    Full Text Available Entre junio de 2002 y abril de 2003 se midió el contenido de cadmio total y disuelto entre la superficie y los 100 m de profundidad, en dos estaciones localizadas en la bahía Mejillones del Sur. El rango de cadmio total y cadmio disuelto en las aguas de esta bahía fue 0,41-10,7 y 0,08-1,61 nM, respectivamente, durante el período de muestreo. Los resultados fueron correlacionados con la estructura físico-química de la columna de agua al momento del muestreo, de manera de estudiar los patrones de variabilidad estacional de este metal en este sistema de surgencia. Las condiciones oceanográficas imperantes durante este período correspondieron a un año normal (no-El Niño. Las masas de agua presentes en la bahía correspondieron a agua subantártica, subtropical y ecuatorial subsuperficial, con diferentes grados de mezcla y estratificación durante el período de estudio. Los perfiles de cadmio presentaron una distribución vertical clásica de un micronutriente. Sin embargo estos perfiles presentaron leves diferencias que pueden ser atribuidas a la condición de mezcla de las masas de agua al interior de la bahía. Un análisis multivariado de los parámetros registrados indicó que la variación temporal de cadmio en las aguas superficiales está asociada a las fluctuaciones de la clorofila a y la temperatura. Esto sugiere que, a escala estacional, la producción de biomasa fitoplanctónica sería el principal factor que controla la distribución de cadmio en esta bahía. Por otro lado, a pesar de que el cadmio es un metal redox sensitivo no se encontró un efecto significativo de la disponibilidad de oxígeno sobre el comportamiento de este metal, de manera que la condición micróxica de las aguas de fondo de la bahía no sería un factor preponderante en el flujo de cadmio hacia los sedimentos. La razón Cd/PO4 encontrada en Mejillones es similar a la reportada en otras zonas costeras de Chile. Los bajos valores y la tendencia temporal

  14. Algal wrack deposits and macroinfaunal arthropods on sandy beaches of the Chilean coast Depósitos de algas varadas y artrópodos macroinfaunales en playas de arena de la costa de Chile

    Directory of Open Access Journals (Sweden)

    EDUARDO JARAMILLO

    2006-09-01

    Full Text Available Four Chilean sandy beaches were sampled during the summer of 2000, to study the role of stranded algal wrack deposits on the population abundances of three detritus feeder species of the macroinfauna that inhabit the upper shore levels of that beaches: the talitrid amphipod Orchestoidea tuberculata Nicolet, the tylid isopod Tylos spinulosus Dana and the tenebrionid insect Phalerisida maculata Kulzer. The beaches were Apolillado (ca. 29° S, Quidico (ca. 38° S, Guabún and Mar Brava (ca. 42° S. Replicated samples were collected with a plastic cylinder (25 cm in diameter from algal wrack deposits including the sediments beneath the wrack and nearby bare sand areas. Samples were collected at two beach levels, one closer to the sea with fresh deposits and other located on the upper beach with dry alga. Algal wrack deposits were mostly composed of the brown algae Macrocystis pyrifera (L., Durvillaea antarctica (Chamisso Hariot and Lessonia nigrescens Bory. O. tuberculata was found in the algal wrack deposits and bare sands collected from Apolillado, Quidico, Guabún and Mar Brava. On the other hand, T. spinulosus was just found at Apolillado, while P. maculata occurred in the sands beneath algal wrack deposits and bare sands collected from Apolillado, Quidico and Guabún. In general, the mean abundances of O. tuberculata, P. maculta and T. spinulosus were significantly higher in those samples collected from sands beneath algal wrack deposits; i.e., 56, 61 and 14 times higher (overall means than in bare sands, respectively. It is concluded that stranded algal wrack deposits indeed promote an increase in population abundances of sandy beach detritus feeders, either because that deposits provide their main food source or shelter against variable environmental conditions (e.g., air temperature and humidity during daylight hours. That might well explain the patchiness shown by these organisms, either across or along shore. This conclusion has important

  15. The distribution, character, and rhenium content of molybdenite in the Aitik Cu-Au-Ag-(Mo) deposit and its southern extension in the northern Norrbotten ore district, northern Sweden.

    OpenAIRE

    Wanhainen, C.; Nigatu, W.; Selby, D.; McLeod, C.; Nordin, R.; Bolin, N-J.

    2014-01-01

    Molybdenite in the Aitik deposit and its southern extension was studied through mineralogical/chemical analysis and laboratory flotation tests. It is demonstrated that molybdenite varies considerably in grain size, ranging from coarse (>20 μm) to very fine (<2 μm) and occurs predominantly as single grains in the groundmass of the rocks, as grain aggregates, and intergrown with chalcopyrite and pyrite. The dominating molybdenite-bearing rocks are the mica schists, the quartz-monzodiori...

  16. [Protomedicato in Chile].

    Science.gov (United States)

    Pérez-Olea, J

    1991-09-01

    In 1566 Alonso de Villadiego was nominated by the Chilean Cabildo as "Adviser and Examiner in Surgery". By means of this edict, the Spanish Crown paralleled its classical health organization, inspired in rules coming from XIIIth century. The Hospital del Socorro was the focal point of these activities. It turned to be prosperous under the administration of "San Juan de Dios" monks (1617), who rebaptized the Hospital with their name. During the administration of the "Universidad de San Felipe" (1738-1839), the Protomedicato followed the standards imposed by the Cahir of Prima Medicina. Domingo Nevin, Frenchman, and José Antonio Ríos, Chilean, were the first and the last doctors in charge of this task. Ríos conducted the antivariolic campaign, supervised the "Midwifery Law" and controlled the medical and paramedical practice. Afterwards, the Institution plunged into a profound crisis to reflourish in 1833 when it was incorporated within the structure of the School of Medicine. Blest, Cox, Bustillos and Moran were the architects of its splendour. With the foundation of the Universidad de Chile in 1842, its Faculty of Medicine took over the Protomedicato functions. The Institution came to an end in 1892.

  17. Country watch: Chile.

    Science.gov (United States)

    Montoya Leiva, M

    1996-01-01

    Servicio Paz y Justicia (SERPAJ) is a nongovernmental organization (NGO) established in Chile in 1977. It supports fundamental human dignity and rights by fighting discrimination and exclusion based upon individual differences. SERPAJ promotes training, organization, and the political participation of community members as part of the democratic process, working mainly with the at risk women, street children, and youth of Santiago's working-class neighborhoods. Groups participate in workshops and training courses on human rights and development, civic education, and methods of non-violent community action. In 1987, SERPAJ-Sur Oriente began to include the topic of sexuality and AIDS/STDs in courses training working-class women as community human rights agents. The NGO is therefore one of the first mainstream Chilean human rights organizations to incorporate HIV/AIDS issues. A basic facts brochure was developed, followed by a pilot education project developed in one neighborhood which was then systematically replicated in other neighborhoods. The comments of some people who have participated in SERPAJ workshops are presented.

  18. complejidad en Chile

    Directory of Open Access Journals (Sweden)

    Miguel Alejandro Bustamante-Ubilla

    2015-01-01

    Full Text Available El presente estudio tiene por objetivo caracterizar el clima organizacional al interior de 2 hospitales dealta complejidad de Chile, determinando las dimensiones más y menos influyentes. Para su desarrollose aplicó un cuestionario que consta de 71 variables agrupadas en 14 dimensiones a una muestra de561 funcionarios. La interpretación de los resultados se realizó a través del análisis del valor prome-dio estandarizado y su confiabilidad ratificada mediante el alfa de Cronbach. A partir de lo anterior, sedeterminó que las dimensiones que influyen por encima del promedio fueron: identidad, motivaciónlaboral y responsabilidad; en tanto que las dimensiones que muestran un nivel de impacto por debajodel promedio resultaron ser: equipo y distribución de personas y material, administración del conflictoy comunicación.© 2015 Universidad ICESI. Publicado por Elsevier España, S.L.U. Este es un artículo Open Access bajo lalicencia CC BY (http://creativecommons.org/licenses/by/4.0/.

  19. 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...

  20. 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...

  1. Coronation Hill U-Au mine, South Alligator Valley, Northern Territory: an epigenetic sandstone-type deposit hosted by debris-flow conglomerate

    International Nuclear Information System (INIS)

    Needham, R.S.; Stuart-Smith, P.G.

    1987-01-01

    The host rock at the Coronation Hill U-Au mine is a debris flow conglomerate, developed in a high-energy fluvial environment during deposition of the Coronation Sandstone of the El Sherana Group. Mineralisation took place by movement of low-temperature fluids from the U-enriched volcanics into the conduit sandstone and eventually into the reduced debris flow conglomerate and carbonaceous shale

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

    Science.gov (United States)

    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.

  3. 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.

  4. 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.

  5. The development condition of longitudinal channels of a Lower Cretaceous formation and its perspective for sandstone type uranium deposits in the Erlian basin, northern China

    International Nuclear Information System (INIS)

    Qin, M.; Xu, Q.; Liu, W.; Song, J.; Chen, D.; Wei, S.

    2014-01-01

    The palaeochannel, which is classified as basal and interformational types on the basis of geological setting, is an important host for the sandstone type uranium deposit. Diversities exist in development conditions and uranium minerogenetic potential of the two types of palaeochanneles. The Erlian basin, about 105 km"2 and adjacent to channel-type uranium deposit provinces in Russia and Mongolia, is one of main uraniferous basins in the north of China. It is significant to research into development conditions of palaeochannels for uranium mineral exploration in the Erlian basin. 1. Geological background: The Erlian basin consists of five depressions which divide the basin and form alternations with uplifts and depressions. Sedimentary capping strata of the basin mainly is the Lower Cretaceous Bayanhua group (K1b) which consists of the Aershan group (K1ba), Tenger group (K1bt) and Saihan group (K1bs) from bottom to top. The Saihan group, which is the product in the phase of depression, is the most important uranous strata in the Erlian basin. 2. Development characteristic and condition of the longitudinal palaeochannel of the Saihan formation: Large-scale longitudinal multi-palaeochannels are identified in the center and northeast of the basin, such as the QiHaRiGeTu-SaiHanGaoBi palaeochannel (CH01), BaYanWuLa palaeochannel (CH02) and GaoLiHan palaeochanne l(CH03), et al., which character the length from several 10s of km to 100 km, width of several 10s of km and thickness of sand bodies from 20 m to 130 m, more or less. Palaeochannels of the Saihan formation are interformational type because the underlay is argillite at the top of the Tenggeer formation. Restrictive geological environments and conditions are necessary to form longitudinal channels and mainly are as follows: (1) the basin in the sustained step of depression; (2) sharp gradient (>5°?) in parts of sub-depressions and sufficient sedimentary supply from the upstream; (3) elongate erosional lowlands or

  6. Permian depositional age of metaturbidites of the Duque de York Complex, southern Chile: U-Pb SHRIMP data and palynology Edad pérmica de sedimentación de las metaturbiditas del Complejo Duque de York, sur de Chile: datos mediante U-Pb SHRIMP y palinología

    Directory of Open Access Journals (Sweden)

    Fernando A Sepúlveda

    2010-07-01

    Full Text Available The Duque de York Complex (DYC is part of the low grade metamorphic accretionary complexes of the pre-Andean Patagonian 'basement'. It is a sedimentary succession exposed along the western margin of southernmost South America. New U-Pb zircon ages and palynological data restrict the maximum depositional age of the DYC to the limit between the early Permian (Kungurian and the middle Permian (Roadian. The palynological association recorded in the DYC, characterized mainly by Gymnospermopsida pollen, indicates a humid environment of forest with an under-growth of ferns. Regional paleogeographic correlations point out that an interpretation of DYC as an autochthonous terrane cannot be discarded, contrasting with previous hypotheses which suggest an allochthonous character for this complex.El Complejo Duque de York (CDY forma parte de los complejos metamórficos acrecionarios del 'basamento' pre-Andino de la Patagonia, correspondiendo a una sucesión sedimentaria que añora a lo largo del margen occidental austral de Sudamérica. Nuevas edades U-Pb en circón, en combinación con información palinológica, permiten acotar la maxima edad de depósito posible del CDY al límite entre el Pérmico temprano (Kunguriano y el Pérmico medio (Roadiano. La asociación palinológica registrada en el CDY está caracterizada por Gymnospermopsida, e indica un ambiente húmedo de bosque con sotobosque de heléchos. Las correlaciones paleogeográñcas apuntan a que la condición de terreno autóctono del CDY no puede ser descartada, lo que se contrapone a hipótesis anteriores, las que sugieren un carácter alóctono para este complejo.

  7. The transtensional offshore portion of the northern San Andreas fault: Fault zone geometry, late Pleistocene to Holocene sediment deposition, shallow deformation patterns, and asymmetric basin growth

    Science.gov (United States)

    Beeson, Jeffrey W.; Johnson, Samuel Y.; Goldfinger, Chris

    2017-01-01

    We mapped an ~120 km offshore portion of the northern San Andreas fault (SAF) between Point Arena and Point Delgada using closely spaced seismic reflection profiles (1605 km), high-resolution multibeam bathymetry (~1600 km2), and marine magnetic data. This new data set documents SAF location and continuity, associated tectonic geomorphology, shallow stratigraphy, and deformation. Variable deformation patterns in the generally narrow (∼1 km wide) fault zone are largely associated with fault trend and with transtensional and transpressional fault bends.We divide this unique transtensional portion of the offshore SAF into six sections along and adjacent to the SAF based on fault trend, deformation styles, seismic stratigraphy, and seafloor bathymetry. In the southern region of the study area, the SAF includes a 10-km-long zone characterized by two active parallel fault strands. Slip transfer and long-term straightening of the fault trace in this zone are likely leading to transfer of a slice of the Pacific plate to the North American plate. The SAF in the northern region of the survey area passes through two sharp fault bends (∼9°, right stepping, and ∼8°, left stepping), resulting in both an asymmetric lazy Z–shape sedimentary basin (Noyo basin) and an uplifted rocky shoal (Tolo Bank). Seismic stratigraphic sequences and unconformities within the Noyo basin correlate with the previous 4 major Quaternary sea-level lowstands and record basin tilting of ∼0.6°/100 k.y. Migration of the basin depocenter indicates a lateral slip rate on the SAF of 10–19 mm/yr for the past 350 k.y.Data collected west of the SAF on the south flank of Cape Mendocino are inconsistent with the presence of an offshore fault strand that connects the SAF with the Mendocino Triple Junction. Instead, we suggest that the SAF previously mapped onshore at Point Delgada continues onshore northward and transitions to the King Range thrust.

  8. 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

  9. Forest nursery management in Chile

    Science.gov (United States)

    Rene Escobar R.; Manuel Sanchez O.; Guillermo Pereira C.

    2002-01-01

    The forest economy in Chile is based on products from artificial reforestation efforts on approximately 2 million ha. From these, about 1.5 million ha (75%) are planted with Pinus radiata, 400,000 ha (20%) with species of Eucalyptus, principally E. globulus and E. nitens, and the rest (5%) composed by other...

  10. A Controversial Source for a 1.2-1.5 km3 Debris Avalanche Deposit in Northern Ecuador: A Case Study of Cubilche Volcano

    Science.gov (United States)

    Mulas, M.; Bowman, L.; Roverato, M.; Larrea Marquez, P.; Casado, I.

    2017-12-01

    Debris avalanche deposits (DAD) are common products of catastrophic volcanic edifice collapses. These failure events leave peculiar horseshoe-shaped scars on the summits of stratovolcanoes. Cubilche Volcano (3826 masl), located S of the city of Ibarra (Imbabura Province) and E of the dormant Imbabura volcano, displays a distinct horseshoe-shaped scar towards the N. This post-collapse edifice that we name "Old Cubilche Volcano" (OCV) hosts an additional edifice, "Young Cubilche Volcano" (YCV), which partially covers the southern flank of OCV. Knowledge of Cubilche is critical because of its close proximity to the provincial capital of Ibarra. In fact, Imbabura edifice was built over the northwestern slope of OCV and partially covered it. The studied DAD (unknown age) has been recently linked to Imbabura Volcano as a product of its northwestern sector collapse (LePennec et al., 2011). Alternatively, previous work proposed that the DAD, covering 80 km2 and reaching >13 km distance with an estimated volume of 1.6 km3, was the product of the older OCV (Ruiz, 2003). To constrain the source of the DAD, detailed fieldwork with granulometric, petrological, and geochemical analyses of the deposit was conducted. Preliminary data points to Cubilche as the most likely source for this DAD in accordance with Ruiz (2003). The shaded relief image of the present day OCV shows that the morphology of the volcano is well-preserved on its southern, eastern, and western flanks. This allows the reconstruction of the morphology of OCV prior to the collapse through interpolation of elevation and altitude data of the preserved flanks. A DEM of the present day topography (12m horizontal resolution) obtained from TanDEM-X data was used for extrapolating the morphology. This methodology shows that the post-collapse base of the amphitheater was reconstructed by removing the relief of the present day YCV. The reconstructed topography of OCV shows that it could have been a symmetric cone, reaching

  11. The Distribution, Character, and Rhenium Content of Molybdenite in the Aitik Cu-Au-Ag-(Mo Deposit and Its Southern Extension in the Northern Norrbotten Ore District, Northern Sweden

    Directory of Open Access Journals (Sweden)

    Christina Wanhainen

    2014-12-01

    Full Text Available Molybdenite in the Aitik deposit and its southern extension was studied through mineralogical/chemical analysis and laboratory flotation tests. It is demonstrated that molybdenite varies considerably in grain size, ranging from coarse (>20 μm to very fine (<2 μm and occurs predominantly as single grains in the groundmass of the rocks, as grain aggregates, and intergrown with chalcopyrite and pyrite. The dominating molybdenite-bearing rocks are the mica schists, the quartz-monzodiorite, and the Salmijärvi biotite-amphibole gneiss, the latter containing mostly medium-coarsegrained molybdenite. Later geological features, such as garnet-magnetite-anhydrite-K feldspar alteration and pegmatite dikes appear to be responsible for a significant part of the distribution pattern of molybdenite. Molybdenite grains contain up to 1587 ppm Re, with an average of 211 ± 10 ppm in Aitik molybdenite and 452 ± 33 ppm in Salmijärvi molybdenite. The higher Re concentrations are found in molybdenite associated with sericite- and quartz-amphibole-magnetite altered rocks, whereas low Re values occur in rocks in which potassic alteration is prominent. Molybdenite recovery is influenced by the mineralogy of the host rock and the alteration grade; hence both of these factors will have an impact on potential recoveries. The recovery of molybdenite was lower from flotation feeds with significant amounts of Mg-bearing clay-micas.

  12. Zircon U-Pb geochronology and Sr-Nd-Pb-Hf isotopic constraints on the timing and origin of Mesozoic granitoids hosting the Mo deposits in northern Xilamulun district, NE China

    Science.gov (United States)

    Shu, Qihai; Lai, Yong; Zhou, Yitao; Xu, Jiajia; Wu, Huaying

    2015-12-01

    Located in the east section of the Central Asian orogen in northeastern China, the Xilamulun district comprises several newly discovered molybdenum deposits, primarily of porphyry type and Mesozoic ages. This district is divided by the Xilamulun fault into the southern and the northern parts. In this paper, we present new zircon U-Pb dating, trace elements and Hf isotope, and/or whole rock Sr-Nd-Pb isotopic results for the host granitoids from three Mo deposits (Yangchang, Haisugou and Shabutai) in northern Xilamulun. Our aim is to constrain the age and petrogenesis of these intrusions and their implications for Mo mineralization. Zircon U-Pb LA-ICP-MS dating shows that the monzogranites from the Shabutai and Yangchang deposits formed at 138.4 ± 1.5 and 137.4 ± 2.1 Ma, respectively, which is identical to the molybdenite Re-Os ages and coeval well with the other Mo deposits in this region, thereby indicating an Early Cretaceous magmatism and Mo mineralization event. Zircon Ce/Nd ratios from the mineralized intrusions are significantly higher than the barren granites, implying that the mineralization-related magmas are characterized by higher oxygen fugacity. These mineralized intrusions share similar zircon in-situ Hf and whole rock Sr-Nd isotopic compositions, with slightly negative to positive εHf(t) ranging from - 0.8 to + 10.0, restricted εNd(t) values from - 3.7 to + 1.6 but a little variable (87Sr/86Sr)i ratios between 0.7021 and 0.7074, indicative of formation from primary magmas generated from a dominantly juvenile lower crust source derived from depleted mantle, despite diverse consequent processes (e.g., magma mixing, fractional crystallization and crustal contamination) during their evolution. The Pb isotopes (whole rock) also show a narrow range of initial compositions, with (206Pb/204Pb)i = 18.03-18.88, (207Pb/204Pb)i = 15.48-15.58 and (208Pb/204Pb)i = 37.72-38.28, in agreement with Sr-Nd-Hf isotopes reflecting the dominance of a mantle component

  13. Effects of volcanic and hydrologic processes on forest vegetation: Chaitén Volcano, Chile

    Science.gov (United States)

    Frederick J. Swanson; Julia A. Jones; Charles M. Crisafulli; Antonio. Lara

    2013-01-01

    The 2008-2009 eruption of Chaiten Volcano (Chile) involved a variety of volcanic and associated hydrologic processes that damaged nearby forests. These processes included coarse (gravel) and fine (silt to sand) tephra fall, a laterally directed blast, fluvial deposition of remobilized tephra, a variety of low-temperature mass-movement processes, and a pyroclastic flow...

  14. 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...

  15. Chiliques volcano, Chile

    Science.gov (United States)

    2002-01-01

    A January 6, 2002 ASTER nighttime thermal infrared image of Chiliques volcano in Chile shows a hot spot in the summit crater and several others along the upper flanks of the edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24,2000 showed no thermal anomaly. Chiliques volcano was previously thought to be dormant. Rising to an elevation of 5778 m, Chiliques is a simple stratovolcano with a 500-m-diameter circular summit crater. This mountain is one of the most important high altitude ceremonial centers of the Incas. It is rarely visited due to its difficult accessibility. Climbing to the summit along Inca trails, numerous ruins are encountered; at the summit there are a series of constructions used for rituals. There is a beautiful lagoon in the crater that is almost always frozen.The daytime image was acquired on November 19, 2000 and was created by displaying ASTER bands 1,2 and 3 in blue, green and red. The nighttime image was acquired January 6, 2002, and is a color-coded display of a single thermal infrared band. The hottest areas are white, and colder areas are darker shades of red. Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.Both images cover an area of 7.5 x 7.5 km, and are centered at 23.6 degrees south latitude, 67.6 degrees west longitude.These images were acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.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 Economy, Trade and Industry. A joint U

  16. Identifying spectrometric signatures of phosphate deposits and enclosing sediments in Al-Awabed area, Northern Palmyrides, Central Syria, by the use of statistical factor analysis

    International Nuclear Information System (INIS)

    Asfahani, J.; Al-Hent, R.; Aissa, M.

    2007-01-01

    In previous published research, a factor analysis approach has been applied to airborne spectrometric data of Al-Awabed area, Northern Palmyrides, Syria. A model of four factors (F1, F2, F3 and F4) has proven to be sufficient to represent the acquired data, where 94% of the total data variance is explained. A powerful tool for direct differentiation of various rocks units is obtained through the mapping of these four factors, where a scored lithological map including 11 radiometric units is established. Ninety nine rock samples have been taken according to the four factors to be analyzed by the gamma spectrometry technique in order to determine their content of e U, e Th and K%. The analysis of 65 samples according to F1 indicates that uranium concentration varies between 2.74 and 123.3 ppm with an average of 58.85 ppm and a standard deviation of 32.53 ppm. The analysis of 18 samples taken according to F2 indicates that K% concentration varies between 0.001 and 0.324 with an average of 0.145 and a standard deviation of 0.122. The analysis of 16 samples taken according to F3 indicates that K% concentration varies between 0.024 and 0.558 with an average of 0.227 and a standard deviation of 0.133. These gamma-results are expected and fit very well with the results obtained by the factor analysis approach. Therefore, the validity and efficacy of the factor analysis approach, to be widely used as a guide in exploration and smart sampling for mining programs, are well demonstrated. The established phosphate maps show a width extension and distribution, and clearly indicate the potential of the research area, and it merits to be followed by economic exploration

  17. Prediction of Exploration Target Areas for GEM Deposits in Mogok Stone Tract, Northern Myanmar by Integrating Remote Sensing and Geoscience Data

    Science.gov (United States)

    Oo, Tin Ko

    2011-07-01

    The Mogok Stone Tract area has long been known for world famous finest ruby since 1597. The Mogok area lies in northern Myanmar and is located at about 205.99km northeast from Mandalay, the second largest city of Myanmar. The Mogok Group of metasedimentary rocks is divided into four units: (1) Wabyudaung Marble, (2) Ayenyeinchantha Calc-silicate, (3) Gwebin Quartzite, and (4) Kabe Gneiss. Igneous rocks in the Mogok area are classified into two units: (1) Kabaing Granite and (2) Pingutaung Leucogranite. The Mogok area has a complex structure involving several folds and faults. Using marbles and calc-silicates as marker horizons, a series of anticline and syncline can be identified such as Mogok syncline, Ongaing anticline, Bawpadan syncline, and Kyatpyin anticline. All the foldings show a low-angle plunge to the south. The main precious stones of the Mogok area are ruby and sapphire; and the other important semi-precious stones are spinel, topaz, peridot, garnet, apatite, beryl, tourmaline (rubellite), quartz, diopside, fluorite, and enstatite. Geological and remote sensing data are processed to extract the indicative features of gem mineralized areas: lithology, structure, and hydrothermal alteration. Density slice version of Landsat ETM band ratios 5/7 is used to map clay alterations. Filtering Landsat ETM band 5 by using edge detection filter is applied for lineament mapping. Spatial integration of various geoscience and remote sensing data sets such as geological maps, Landsat ETM images, and the location map of gem mines show the distribution of alteration zones associated with the gem mineralization in the study area. Geographic Information System (GIS) model has been designed and implemented by ARCVIEW software package based on the overlay of lithologic, lineament, and alteration vector maps. This process has resulted in delineation of most promising areas of probable gem mineralized zones as on the output map.

  18. Mineralogical, chemical, and crystallographic properties of supergene jarosite-group minerals from the Xitieshan Pb-Zn sulfide deposit, northern Tibetan Plateau, China

    Science.gov (United States)

    Chen, Lei; Li, Jian-Wei; Rye, Robert O.; Benzel, William H.; Lowers, H.A.; He, Ming-Zhong

    2013-01-01

    Supergene jarosite-group minerals are widespread in weathering profiles overlying Pb-Zn sulfide ores at Xitieshan, northern Tibetan Plateau, China. They consist predominantly of K-deficient natrojarosite, with lesser amounts of K-rich natrojarosite and plumbojarosite. Electron microprobe (EMP) analyses, scanning electron microcopy (SEM) investigation, and X-ray mapping reveal that the jarosite-group minerals are characterized by spectacular oscillatory zoning composed of alternating growth bands of K-deficient and K-bearing natrojarosite (K2O >1 wt.%). Plumbojarosite, whenever present, occurs as an overgrowth in the outermost bands, and its composition can be best represented by K0.29Na0.19Pb0.31Fe2.66Al0.22(SO4)1.65(PO4)0.31(AsO4)0.04(OH)7.37. The substitution of monovalent for divalent cations at the A site of plumbojarosite is charge balanced by the substitution of five-valent for six-valent anions in XO,4/sub> at the X site. Thermogravimetric analysis (TGA) of representative samples reveal mass losses of 11.46 wt.% at 446.6 °C and 21.42 wt.% at 683.4 °C due to dehydroxylation and desulfidation, respectively. TGA data also indicate that the natrojarosite structure collapses at 446.6 °C, resulting in the formation of NaFe(SO4)2 and minor hematite. The decomposition products of NaFe(SO4) are hematite and Na,2SO4. Powder X-ray diffraction (XRD) analyses show that the jarosite-group minerals have mean unit-cell parameters of a=7.315 ä and c=016.598 ä. XRD and EMP data support the view that substitutions of Na for K in the A site and full Fe occupancy in the B site can considerably decrease the unit-cell parameter c, but only slightly increase a. The results from this study suggest that the observed oscillatory zoning of jarosite-group minerals at Xitieshan resulted mainly from substitutions of K for Na at the A site and P for S at the X site.

  19. Contrasting isotopic signatures between anthropogenic and geogenic Zn and evidence for post-depositional fractionation processes in smelter-impacted soils from Northern France

    Science.gov (United States)

    Juillot, Farid; Maréchal, Chloe; Morin, Guillaume; Jouvin, Delphine; Cacaly, Sylvain; Telouk, Philipe; Benedetti, Marc F.; Ildefonse, Philippe; Sutton, Steve; Guyot, François; Brown, Gordon E., Jr.

    2011-05-01

    Zinc isotopes have been studied along two smelter-impacted soil profiles sampled near one of the largest Pb and Zn processing plants in Europe located in northern France, about 50 km south of Lille. Mean δ 66Zn values along these two soil profiles range from +0.22 ± 0.17‰ (2 σ) to +0.34 ± 0.17‰ (2 σ) at the lowest horizons and from +0.38 ± 0.45‰ (2 σ) to +0.76 ± 0.14‰ (2 σ) near the surface. The δ 66Zn values in the lowest horizons of the soils are interpreted as being representative of the local geochemical background (mean value +0.31 ± 0.38‰), whereas heavier δ 66Zn values near the surface of the two soils are related to anthropogenic Zn. This anthropogenic Zn occurs in the form of franklinite (ZnFe 2O 4)-bearing slag grains originating from processing wastes at the smelter site and exhibiting δ 66Zn values of +0.81 ± 0.20‰ (2 σ). The presence of franklinite is indicated by EXAFS analysis of the topsoil samples from both soil profiles as well as by micro-XANES analysis of the surface horizon of a third smelter-impacted soil from a distant site. These results indicate that naturally occurring Zn and smelter-derived Zn exhibit significantly different δ 66Zn values, which suggests that zinc isotopes can be used to distinguish between geogenic and anthropogenic sources of Zn in smelter-impacted soils. In addition to a possible influence of additional past sources of light Zn (likely Zn-sulfides and Zn-sulfates directly emitted by the smelter), the light δ 66Zn values in the surface horizons compared to smelter-derived slag materials are interpreted as resulting mainly from fractionation processes associated with biotic and/or abiotic pedological processes (Zn-bearing mineral precipitation, Zn complexation by organic matter, and plant uptake of Zn). This conclusion emphasizes the need for additional Zn isotopic studies before being able to use Zn isotopes to trace sources and pathways of this element in surface environments.

  20. Fog deposition to the Atacama desert

    Science.gov (United States)

    Westbeld, A.; Klemm, O.; Griessbaum, F.; Sträter, E.; Larrain, H.; Osses, P.; Cereceda, P.

    2010-07-01

    In the Atacama Desert, one of the driest places on earth, fog deposition plays an important role for the water balance and for the survival of vulnerable ecosystems. The eddy covariance method, previously applied for the quantification of fog deposition to forests in various parts of the world, was used for the first time to measure deposition of fog water to a desert. We estimated the amount of water available for the ecosystem by deposition and determined the relevant processes driving fog deposition. This is especially important for the species Tillandsia landbecki living in coastal Atacama at the limit of plant existence with fog and dew being the only sources of liquid water. Between 31 July and 19 August, 2008, measurements were realized in a 31 ha large Tillandsia carpet at Cerro Guanaco, located 15 km south of Iquique, northern Chile. Several data quality assurance procedures were applied. For the values in compliance with the applied criteria, the mean total deposition per hour was determined (0.04 L per m2) for foggy periods. This number was applied to estimate the amount of water deposited during the measuring period, during the entire month of August 2008, and throughout a whole year. For August 2008, a frequency of fog of 16 %, as established during the measuring period, was assumed. The frequency for a whole year was estimated from the differences of the collected amount of water obtained with standard fog collectors installed at Cerro Guanaco in an earlier study. Calculations resulted in an amount of 2.5 L per m2 of deposited fog water for the measuring period. During the entire August, 4.4 L per m2 have likely been available, and for a whole year, a total of 25 L per m2 was estimated to have reached the surface. Inaccuracies could have been caused by the low amount of data applied, and by a possible underestimation of the deposition due to additional formation of radiation fog during the fog events. Three days were used for further analysis because

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  3. Socialisme i Chile efter Pinochet

    DEFF Research Database (Denmark)

    Cristoffanini, Pablo Rolando

    2008-01-01

    Chile bliver ofte præsenteret som et paradigme for resten af det latinamerikanske kontinent: Et land med høj økonomisk vækst og politisk stabilitet. Landet har endda haft to socialistiske præsidenter siden 2000, den sidste den første kvindelige præsident. Succeshistorien har en bagside: De...... socialistiske regeringer har accepteret et begrænset demokrati og videreført en nyliberal økonomisk politik, der har bragt dem på konfrontationskurs med massebevægelserne og isoleret Chile fra de andre lande i regionen, der søger integration og gensidig støøte. Udgivelsesdato: Februar...

  4. Global deposition of airborne dioxin.

    Science.gov (United States)

    Booth, Shawn; Hui, Joe; Alojado, Zoraida; Lam, Vicky; Cheung, William; Zeller, Dirk; Steyn, Douw; Pauly, Daniel

    2013-10-15

    We present a global dioxin model that simulates one year of atmospheric emissions, transport processes, and depositions to the earth's terrestrial and marine habitats. We map starting emission levels for each land area, and we also map the resulting deposits to terrestrial and marine environments. This model confirms that 'hot spots' of deposition are likely to be in northern Europe, eastern North America, and in parts of Asia with the highest marine dioxin depositions being the northeast and northwest Atlantic, western Pacific, northern Indian Ocean and the Mediterranean. It also reveals that approximately 40% of airborne dioxin emissions are deposited to marine environments and that many countries in Africa receive more dioxin than they produce, which results in these countries being disproportionately impacted. Since human exposure to dioxin is largely through diet, this work highlights food producing areas that receive higher atmospheric deposits of dioxin than others. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. 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...

  6. 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

  7. Northern employment

    International Nuclear Information System (INIS)

    Zavitz, J.

    1997-01-01

    Hiring practices and policies and employment opportunities that were available in the Beaufort Sea and MacKenzie Delta project for local residents and for people from southern Canada were dealt with in this chapter. Depending on the source, Northern hiring was a mere token, or a genuine and successful effort on the part of the companies to involve the native population and to share with them the benefits of the project. The fact remains that opening up job opportunities for Northerners was not easily attained, and would never have been realized without the involvement of government and community organizations. Government also played a major role in developing policies and training regimes. By the end of exploration operations, the hiring of Northern residents in the oil and gas industry had become a requirement of drilling applications. Training programs were also created to ensure that Northern residents received the means necessary to take advantage of Northern employment opportunities

  8. Geology of volcanogenic massive sulfide deposit near Meli ...

    African Journals Online (AJOL)

    VMS) deposit near Meli/Rahwa, northern Ethiopia are presented in the paper. The study area forms part of Neoproterozoic basement of northern Ethiopia and southern part of the Arabian Nubian Shield (ANS). Selected surface rock samples of ...

  9. 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…

  10. Geochronology, geochemistry, and Sr-Nd-Pb-Hf isotopes of the Zhunsujihua granitoid intrusions associated with the molybdenum deposit, northern Inner Mongolia, China: implications for petrogenesis and tectonic setting

    Science.gov (United States)

    Zhang, Xiaojun; Lentz, David R.; Yao, Chunliang; Liu, Rui; Yang, Zhen; Mei, Yanxiong; Fan, Xianwang; Huang, Fei; Qin, Ying; Zhang, Kun; Zhang, Zhenfei

    2018-03-01

    The Zhunsujihua porphyry molybdenum deposit, located in northern Inner Mongolia of China that belongs to Central-Asian Orogenic Belt (CAOB), is the only Mo deposit formed in the late Carboniferous in this area so far. Its mineralization is mainly restricted to the Zhunsujihua granitoid intrusions, which are composed of the main granodiorite (GD) and crosscutting, virtually coeval minor syn-ore leucogranite (LG) and diorite porphyry (DP) dykes. LA-ICP-MS zircon U-Pb dating yields crystallization ages of 300.0 ± 2.0, 299.3 ± 2.0, and 299.0 ± 2.6 Ma for the GD, LG, and DP, respectively. The major and trace element lithogeochemical data show that the GD and LG are metaluminous to weakly peraluminous, high-K calc-alkaline series with I-type granite characteristics, strongly oxidized, with low concentrations of Ba, Nb, Sr, P, and Ti and elevated K and Rb contents, indicating typical arc magmatic features. The LG is a product derived by extensive fractional crystallization of a parental magma similar to the GD as evident from the lower Eu/Eu*, Nb/Ta, Zr/Hf, and T Zr. The moderately altered DP exhibits high concentrations of K, Rb, Cs, LREE, Y, and low Sr/Y, with a positive ɛ Nd (300 Ma), which indicates a mantle or juvenile source associated with an arc setting. The Sr-Nd-Hf isotope data show low I Sr (0.70406-0.70461) and moderate ɛ Nd (300 Ma) (-0.9 to 1.5) for the GD and LG, and relatively high ɛ Hf (300 Ma) values (-3.6 to +11.2) for the GD, suggesting the magma mainly originated from the juvenile lower crust that was derived from depleted mantle, with a minor component of ancient continental crust. Lead isotope data have characteristics of a lower crust source with minor contamination by upper crustal material. Combined with previous research, the Zhunsujihua granitoid intrusions developed in an intracontinental volcanic arc (Uliastai) associated with northward subduction of the Paleo-Asian Ocean plate during late Carboniferous to early Permian; this suggests

  11. 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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. [Antimicrobial susceptibility in Chile 2012].

    Science.gov (United States)

    Cifuentes-D, Marcela; Silva, Francisco; García, Patricia; Bello, Helia; Briceño, Isabel; Calvo-A, Mario; Labarca, Jaime

    2014-04-01

    Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.

  17. 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

  18. Field survey of the 16 September 2015 Chile tsunami

    Science.gov (United States)

    Lagos, Marcelo; Fritz, Hermann M.

    2016-04-01

    On the evening of 16 September, 2015 a magnitude Mw 8.3 earthquake occurred off the coast of central Chile's Coquimbo region. The ensuing tsunami caused significant inundation and damage in the Coquimbo or 4th region and mostly minor effects in neighbouring 3rd and 5th regions. Fortunately, ancestral knowledge from the past 1922 and 1943 tsunamis in the region along with the catastrophic 2010 Maule and recent 2014 tsunamis, as well as tsunami education and evacuation exercises prompted most coastal residents to spontaneously evacuate to high ground after the earthquake. There were a few tsunami victims; while a handful of fatalities were associated to earthquake induced building collapses and the physical stress of tsunami evacuation. The international scientist joined the local effort from September 20 to 26, 2015. The international tsunami survey team (ITST) interviewed numerous eyewitnesses and documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns, performance of the navigation infrastructure and impact on the natural environment. The ITST covered a 500 km stretch of coastline from Caleta Chañaral de Aceituno (28.8° S) south of Huasco down to Llolleo near San Antonio (33.6° S). We surveyed more than 40 locations and recorded more than 100 tsunami and runup heights with differential GPS and integrated laser range finders. The tsunami impact peaked at Caleta Totoral near Punta Aldea with both tsunami and runup heights exceeding 10 m as surveyed on September 22 and broadcasted nationwide that evening. Runup exceeded 10 m at a second uninhabited location some 15 km south of Caleta Totoral. A significant variation in tsunami impact was observed along the coastlines of central Chile at local and regional scales. The tsunami occurred in the evening hours limiting the availability of eyewitness video footages. Observations from the 2015 Chile tsunami are compared against the 1922, 1943, 2010 and 2014 Chile tsunamis. The

  19. The Maritime Cultural Landscape of Northern Patagonia

    Science.gov (United States)

    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.

  20. President of Chile at CERN

    CERN Multimedia

    2007-01-01

    The President of Chile, Michelle Bachelet, in the ATLAS cavern with, from left to right, Peter Jenni, ATLAS Spokesman, Vivian Heyl, CONICYT President, and Robert Aymar, CERN Director-General. Robert Aymar, CERN Director-General, and Vivian Heyl, CONICYT President, signing a cooperation agreement between CERN and Chile’s Comisión Nacional de Investigación Científica y Tecnológica (CONICYT).The President of Chile, Michelle Bachelet, paid a visit to CERN during her three-day tour of Switzerland. The charismatic Michelle Bachelet and her large delegation were greeted by the CERN Director-General and then taken to see the ATLAS experiment and the LHC. She also took time to meet the Chilean community working at CERN, comprising several physicists in the Theory Group and the ATLAS experiment. The meeting was followed by the signing of a cooperation agreement between CERN and Chile’s Comisión Nacional de Investigación Científi...

  1. Letter from Chile: Re-establishing health care in Chile

    Science.gov (United States)

    Jiménez, Jorge

    1993-01-01

    Chile's long term social policy has produced very impressive outcomes in general health indicators, with a national health service established as early as 1952. During the years of the Pinochet dictatorship (1973-89) public health institutions were greatly affected, with sharp diminution in financing which affected investment and salaries. The democratic government initiated in 1990 faced a difficult situation, with underpaid staff and decrepit hospitals. The ministry took immediate action to improve salaries and start an ambitious health sector reform including investment in infrastructure, technology, and modern management. Decentralisation and autonomy, changes in payment for service mechanisms, and a public-private mix are the main objectives of this reform, keeping the public role as predominant in the proposed structure. This process has been affected by union unrest and public opinion dissatisfaction, which tend to present obstacles to progress in this complicated issue. Imagesp729-ap730-a

  2. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. 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.

  5. 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

  6. The geographic distribution of Argas (Persicargas) miniatus and Argas (Persicargas) persicus (Acari: Argasidae) in America, with morphological and molecular diagnoses from Brazil, Chile and Cuba.

    Science.gov (United States)

    Muñoz-Leal, Sebastián; Venzal, José M; Nava, Santiago; Reyes, Mercedes; Martins, Thiago F; Leite, Romário C; Vilela, Vinicius L R; Benatti, Hector R; Ríos-Rosas, Daniela; Barros-Battesti, Darci M; González-Acuña, Daniel; Labruna, Marcelo B

    2018-01-01

    High similarity of morphological traits has historically overshadowed the identities and distributions of poultry-associated soft ticks Argas (Persicargas) miniatus and Argas (Persicargas) persicus in America. In order to model the occurrence of both parasites in the continent, in the current study we performed morphological and molecular analyses to identify ticks collected in hen houses from Brazil and northern Chile. Combining these results with literature data, and the examination of Argas allotments deposited in the tick collections "Coleção Nacional de Carrapatos Danilo Gonçalves Saraiva" (Brazil), the "Coleção Acarológica do Instituto Butantan São Paulo" (Brazil), and the "Colección Zoológica de la Academia de Ciencia de Cuba" (Cuba), we present a critical list with the localities where A. (P.) miniatus and A. (P.) persicus have been reported in the American continent. Our results confirmed the presence of A. (P.) miniatus in Brazil and Cuba, and A. (P.) persicus in Chile, which in particular, constitutes the first molecularly confirmed report of the later species for South America. Although A. (P.) miniatus and A. (P.) persicus have been documented in 21 American countries, the identity of some reports must still be considered as uncertain until detailed morphological and/or molecular studies are performed. When contrasted to a Köppen-Geiger climate classification, A. (P.) miniatus predominantly occurs in equatorial and A. (P.) persicus in arid climates. However, until undetermined reports of both species are correctly identified, any conclusion on their geo-climatological occurrence throughout the American continent would be rather speculative. Copyright © 2017 Elsevier GmbH. All rights reserved.

  7. 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

  8. 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.

  9. 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.

  10. Mujeres inmigrantes peruanas en Chile

    Directory of Open Access Journals (Sweden)

    Carolina Stefoni

    2002-01-01

    Full Text Available Este artículo reflexiona en torno a la situación de la migración peruana en Chile, en particular sobre la situación de exclusión social y laboral que enfrentan las mujeres inmigrantes en Santiago. La migración peruana se caracteriza por ser eminentemente femenina y con una alta concentración laboral de este grupo en el trabajo doméstico. ¿Por qué se han vuelto las labores la fuente principal de trabajo para estas mujeres?, ¿basta con señalar que se debe a mano de obra más barata o existen otros argumentos de tipo cultural y social que explican por qué empleadores/as chilenos contratan y prefieren a mujeres peruanas?

  11. Intercultural bilingual education in Chile

    Directory of Open Access Journals (Sweden)

    Williams Ibarra Figueroa

    2016-08-01

    Full Text Available This article is based on analysis of the actions of public bodies and institutions that are being created in Chile to meet demand in Intercultural Bilingual Education (IBE. The aim is to analyze the practical training of students in initial teacher training in intercultural basic education at the Catholic University of Temuco. In addition, reveal the working methods of collaborative field between family-school- community partnership in key initial identification and subsequent components and devices in the proper relationship of individuals, in order to establish criteria by biopsychosocial processes from the identity the Other and You as host in the plural diversity of human beings, with aim is to recommend  a public policy with an emphasis on multicultural values of each community, enriching the human condition and biopolitics regarding the integration from the educational training and the role that fits the state.

  12. Chile: perspectives in school health.

    Science.gov (United States)

    Langdon, M C; Gazmuri, C; Venegas, L

    1990-09-01

    The leading health problems of children and adolescents in Chile is reviewed. The Chilean educational system and how the system addresses its principal health problems are described. A school health program is described as well as other educational programs designed and developed by nongovernmental institutions which have a smaller coverage. Current research studies regarding growth and development, child morbidity, nutritional level, and mental health studies are reviewed. In addition, principal challenges that include developing more efficient ways of referring children, enriching the curriculum and teacher training, assigning school hours for health teachers, and enlarging coverage of the health care evaluation programs are outlined. Of special importance is developing prevention programs for parents and children using school and community leaders to prevent health problems in areas such as human sexuality education, decision-making, social abilities, and alcohol and drug abuse. Main efforts should be directed toward low-income families and children to improve life conditions.

  13. Village microgrids: The Chile project

    Energy Technology Data Exchange (ETDEWEB)

    Baring-Gould, E.I.

    1997-12-01

    This paper describes a village application in Chile. The objective was to demonstrate the technical, economic and institutional viability of renewable energy for rural electrification, as well as to allow local partners to gain experience with hybrid/renewable technology, resource assessment, system siting and operation. A micro-grid system is viewed as a small village system, up to 1200 kWh/day load with a 50 kW peak load. It can consist of components of wind, photovoltaic, batteries, and conventional generators. It is usually associated with a single generator source, and uses batteries to cover light day time loads. This paper looks at the experiences learned from this project with regard to all of the facets of planning and installing this project.

  14. Effects of volcanic and hydrologic processes on forest vegetation: Chaitén Volcano, Chile

    OpenAIRE

    Swanson,Frederick J; Jones,Julia A; Crisafulli,Charles M; Lara,Antonio

    2013-01-01

    The 2008-2009 eruption of Chaitén Volcano (Chile) involved a variety of volcanic and associated hydro-logic processes that damaged nearby forests. These processes included coarse (gravel) and fine (silt to sand) tephra fall, a laterally directed blast, fluvial deposition of remobilized tephra, a variety of low-temperature mass-movement processes, and a pyroclastic flow. Each of these geophysical processes constitutes a type of ecosystem disturbance which involves a distinctive suite of distur...

  15. Chile and Mercosur: One Strategic Perspective

    National Research Council Canada - National Science Library

    Oviedo, Humberto

    2000-01-01

    ... a big free trade area. Chile has been proactive to open its economy unilaterally and now is looking for creating the best conditions to participate in some important economic blocks, as a NAFTA, MERCOSUR, the Asian-Pacific...

  16. A decade towards better health in Chile.

    Science.gov (United States)

    Helmke, Irene

    2011-10-01

    In 1990, after 17 years of dictatorship, Chile started rebuilding its political system with a focus on improving social conditions and health. A recent study of the last 10 years shows some positive results. Irene Helmke reports.

  17. May 1960 Puerto Montt, Valdivia, Chile Images

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — On May 22, 1960, a Mw 9.5 earthquake, the largest earthquake ever instrumentally recorded, occurred in southern Chile. The series of earthquakes that followed...

  18. Surface Observations from Punta Arenas, Chile

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Surface Observations from Punta Arenas, in extreme southern Chile. WMO station ID 85934. Period of record 1896-1954. The original forms were scanned at the Museo...

  19. 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)

  20. Iodine-129, Iodine-127 and Caesium-137 in the environment: soils from Germany and Chile

    International Nuclear Information System (INIS)

    Daraoui, A.; Michel, R.; Gorny, M.; Jakob, D.; Sachse, R.; Synal, H.-A.; Alfimov, V.

    2012-01-01

    Soil profiles from Bavaria in southern Germany and from Chile were analysed for 129 I by accelerator mass spectrometry (AMS), for 127 I by inductively coupled plasma mass spectrometry (ICP-MS), and for 137 Cs by gamma-spectrometry. The mean deposition density of 137 Cs in soils from Bavaria was (41 × 1.5 ±1 ) kBq m −2 (geometric mean and geometric standard deviation), originating mostly from the Chernobyl fall-out. The deposition density of 129 I in these soils was (109 × 1.5 ±1 ) mBq m −2 . The dominant sources of 129 I in Bavaria are, however, the reprocessing plants La Hague and Sellafield and not the Chernobyl fall-out. The 129 I/ 127 I isotopic ratios of the Bavarian soils were between 10 −7 and 10 −10 , i.e. 10 2 –10 5 times higher than the ratios observed for the samples from Chile. The 129 I integral deposition densities in Chile, Easter Island and Antarctica were between 0.3 mBq m −2 and 2 mBq m −2 . In these soils, the observed 129 I/ 127 I ratios were about 10 −12 . The soils from Chile allow the determination of the 129 I fall-out from the atmospheric nuclear weapons explosions undisturbed from contaminations due to releases from reprocessing plants. An upper limit of the integral 129 I deposition density of the atmospheric nuclear weapons explosions on the Southern Hemisphere (27°S) is about 1 mBq m −2 . Finally, the dependence of the migration behaviour of 137 Cs, 127 I and of 129 I on the soil properties is discussed. It turns out that there is a distinctly different behaviour of 127 I, 129 I, and 137 Cs in the soils exhibiting different sorption mechanisms for old and recent iodine as well as for 137 Cs. - Highlights: ► I-129 from European reprocessing plants drastically changed its natural abundances. ► We report here inventories of the Cs-137 and I-129 in Bavaria and Chile. ► The dominant sources of I-129 in Bavaria are the European reprocessing plants. ► The dominant sources of I-129 in Chile are the atmospheric

  1. 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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Coastal evidence for Holocene subduction-zone earthquakes and tsunamis in central Chile

    Science.gov (United States)

    Dure, Tina; Cisternas, Marco; Horton, Benjamin; Ely, Lisa; Nelson, Alan R.; Wesson, Robert L.; Pilarczyk, Jessica

    2015-01-01

    The ∼500-year historical record of seismicity along the central Chile coast (30–34°S) is characterized by a series of ∼M 8.0–8.5 earthquakes followed by low tsunamis (tsunami (>10 m), but the frequency of such large events is unknown. We extend the seismic history of central Chile through a study of a lowland stratigraphic sequence along the metropolitan coast north of Valparaíso (33°S). At this site, higher relative sea level during the mid Holocene created a tidal marsh and the accommodation space necessary for sediment that preserves earthquake and tsunami evidence. Within this 2600-yr-long sequence, we traced six laterally continuous sand beds probably deposited by high tsunamis. Plant remains that underlie the sand beds were radiocarbon dated to 6200, 5600, 5000, 4400, 3800, and 3700 cal yr BP. Sediment properties and diatom assemblages of the sand beds—for example, anomalous marine planktonic diatoms and upward fining of silt-sized diatom valves—point to a marine sediment source and high-energy deposition. Grain-size analysis shows a strong similarity between inferred tsunami deposits and modern coastal sediment. Upward fining sequences characteristic of suspension deposition are present in five of the six sand beds. Despite the lack of significant lithologic changes between the sedimentary units under- and overlying tsunami deposits, we infer that the increase in freshwater siliceous microfossils in overlying units records coseismic uplift concurrent with the deposition of five of the sand beds. During our mid-Holocene window of evidence preservation, the mean recurrence interval of earthquakes and tsunamis is ∼500 years. Our findings imply that the frequency of historical earthquakes in central Chile is not representative of the greatest earthquakes and tsunamis that the central Chilean subduction zone has produced.

  5. Coastal evidence for Holocene subduction-zone earthquakes and tsunamis in central Chile

    Science.gov (United States)

    Dure, Tina; Cisternas, Marco; Horton, Benjamin; Ely, Lisa; Nelson, Alan R.; Wesson, Robert L.; Pilarczyk, Jessica

    2015-01-01

    The ∼500-year historical record of seismicity along the central Chile coast (30–34°S) is characterized by a series of ∼M 8.0–8.5 earthquakes followed by low tsunamis (10 m), but the frequency of such large events is unknown. We extend the seismic history of central Chile through a study of a lowland stratigraphic sequence along the metropolitan coast north of Valparaíso (33°S). At this site, higher relative sea level during the mid Holocene created a tidal marsh and the accommodation space necessary for sediment that preserves earthquake and tsunami evidence. Within this 2600-yr-long sequence, we traced six laterally continuous sand beds probably