En el noroeste de la provincia de Santa Cruz, en la Patagonia austral argentina, se ubican los reconocidos destinos turísticos del “Glaciar Perito Moreno” y la localidad de “El Calafate”(El Glaciar ...Perito Moreno se encuentra en un parque nacional, donde se realizan diversas actividades: paseo sobre pasarelas, caminatas de diversa dificultad sobre el glaciar, navegaciones ,mientras que en la ciudad de El Calafate se pueden realizar actividades deportivas sobre el aledaño “Lago Argentino”). El objetivo es analizar los aspectos de Seguridad de cada una de las ofertas , que involucran a visitantes ,turistas y trabajadores del Turismo. Se propone una metodología que, a partir de la identificación de los peligros asociados a las diversas actividades, nos permita a modo de diagnóstico, valorar el riesgo potencial y en función de estos resultados, recomendar las medidas de Prevención correspondientes. Se pretende destacar la importancia de eliminar o minimizar los riesgos presentes y de esta manera asegurar una experiencia agradable, enriquecedora y segura a todos los que están involucrados en las actividades turísticas de los sitios analizados.
We present results of the estimation of surface changes associated with slope instability processes on the Upsala Channel by remote sensing and statistic techniques. Hillslopes, involving lateral ...moraines, of Upsala Channel at the Argentino Lake have become potentially unstable due to the retreat of Upsala Glacier during the last century. The glaciation and deglaciation processes modify the tensions on the slope stability and may generate landslide processes. A landslide movement destroyed the western edge of the Upsala Channel in February 2013. In addition, the region represents a great tourist attraction usually ships navigate through the Upsala Channel seeing impressive landscapes, especially the Upsala Glacier, stand out. Due to this risky situation the necessity of increasing the knowledge in the area has arisen but has not been addressed yet. Therefore, the main goal of the present study is to investigate the multivariate statistical techniques by the principal component analysis (PCA) and discriminative analysis (DA) in four testing areas (TASn). Besides, we include Pearson's correlation coefficient (PCC) and normal distribution (ND) to determine whether the testing areas suffered slope movements or were temporally stable. The study is based on Landsat optical satellite images, acquired during the period from October 2001 to April 2015. The results show that TAS1,2,4 are less stable, whereas TAS5 is a more stable area as compared to another TAS. The PC1 and PC2 principal components explained the total variability of the 76% data. The total apparent error of DA reached 2.2% points. The PCC achieved a positive trend during the years when movement on the slope surface was not observed; while during the periods when slope instability was observed, the correlation showed a negative trend. The TASn that had shown a different behavior presented contrasted Gaussian bells; they are more flattened in those years with instability events.
•The optimal images bands combination is crucial to extract information on the slopes.•The multivariate and bivariatetechniques allow estimating the events of instability.•The Upsala Channel shows paraglacial processes that generate slope instability.
The Río Mayer Formation (Berriasian–Albian) is part of the basal infill of the Austral Basin, southwestern Gondwana. In the Los Glaciares National Park (Santa Cruz Province) seven sections were ...sedimentologically studied in detail. The investigated interval is mainly composed of black mudstones and shales interbedded with marls and fine-grained sandstones. The vertical distribution of these lithologies provided the basis to distinguish three major units (lower, middle and upper). In general, within the Río Mayer Formation, two different developments of the Zoophycos ichnofacies were recognized. First, in the middle unit (Valanginian–Hauterivian), this ichnofacies shows a high degree of bioturbation having a bioturbation index (BI) between 3 and 4; Zoophycos specimens are of large size, the spreiten are nearly 1cm in height and more than 1m in width. This ichnogenus is associated with Chondrites and Bergaueria perata. Environmentally this ichnofacies formed during a transgression, the sedimentation rates were very low and promoted the accumulation of benthic food in the outer shelf. Second, the Zoophycos ichnofacies in the upper unit (Albian) exhibits a less intense degree of bioturbation (BI between 0 and 1) and; Zoophycos is of relatively small size, the spreiten are 0.3cm high and short. Typically are associated Ophiomorpha, Chondrites, Palaeophycus and Teredolites. When this ichnofacies formed, the prodelta margin prograded across the outer shelf and led to enhanced sedimentation rates further offshore resulting in the dilution of the nutrients.
•We study changes in the Zoophycos ichnofacies from the Lower Cretaceous of Patagonia.•Different intensities of bioturbation were recognized linked to environmental factors.•Sedimentation rate controls the availability of food for the Zoophycos trace-makers.
•The applicability of biogenic proxies for host-water isotope reconstructions in Patagonia was tested.•Oxygen isotope ratios of aquatic macrophytes, chironomids and ostracods were compared.•Aquatic ...macrophytes best reflected host-water isotopic composition.•No clear temperature dependency of isotopic fractionation was found for macrophytes and chironomids.
Oxygen stable isotopes (δ18O) of biogenic sedimentary components from lake sediment archives, such as ostracod valves, are frequently used for palaeoclimatic reconstructions. However, the effects of host water isotope changes, temperature-dependent fractionations, and vital effects on the isotopic ratios of such biogenic proxies often cannot be disentangled. Here, δ18O values of ostracod valves, head capsules of chironomid larvae and aquatic macrophyte cellulose from various lake and stream sites in southern Patagonia (41–52°S) are compared with δ18O values of their host waters. The best correlation between δ18O values of bioproxy and host water was obtained for aquatic cellulose exhibiting a slope of the regression of almost unity. Chironomid head capsules showed a strong correlation, but the data set was rather small (seven sites). The δ18O values of ostracod valves showed strong inter-specific vital effects. Strong offsets of ostracod values from isotopic equilibrium are possibly explained by re-working of subfossil valves, seasonality effects or different chemical composition of host waters. A weak, but significant temperature dependency of oxygen isotope fractionation was observed for cellulose of one aquatic taxon (Myriophyllum) and for ostracod calcite, but not for chironomids and aquatic moss cellulose. The present dataset suggests that δ18O values of aquatic cellulose are the most reliable proxy for host water isotope reconstructions, but clearly more investigations are needed to substantiate this finding.
The Berriasian–early Valanginian time interval is well represented in the Rio Mayer Formation in the Río Guanaco area (Austral Basin, Argentina). From this locality, well preserved belemnite shells ...of the genus Belemnopsis sp. and black shales are used to unravel the main palaeoenvironmental conditions of the seas at these high palaeo-latitudes (60°) of southern South America during the Early Cretaceous. Rare earth elements plus yttrium (REY) analyses performed in belemnites rostra reveal Ce anomalies and Y/Ho values that together suggest high oxidizing superficial seawater conditions. On the other hand, sedimentological, ichnological and geochemical (TOC, Ce anomaly and MnO) data, analyzed from the black shale matrix of belemnites, show that they may have been deposited on the bottom of the basin under oxygen deficiency. Cathodoluminescence, scanning electron microscopy, major and trace element geochemistry allowed determining the best preserved microtextures of the belemnites in order to obtain reliable δ18O and δ13C results. Palaeotemperatures calculated from the δ18O results, characterized the studied marine interval from Austral Basin as warm. The belemnites from this Lower Cretaceous succession may have lived under well oxygenated and warm seawater conditions, which were markedly different from those recorded in seafloor sediments (black shales) deposited under suboxic to anoxic conditions. The integration of global palaeotemperature data for the Berriasian–early Valanginian interval, allows suggesting a different gradient for the austral Patagonia at the Southern Hemisphere in relation to those recorded in the Northern Hemisphere.
•C-O isotopes reflect a primary signal in Belemnopsis sp. from the Río Mayer Fm.•Belemnites reveal oxic conditions while black shales indicate anoxic conditions.•The palaeotemperature estimations indicate a warm seawater for the studied interval.•The Early Cretaceous temperature gradients should have been different in both hemispheres.
Glaciar Perito Moreno (hereafter GPM; 50°30′S and 72°50′W) is a major outlet glacier from the South Patagonia Icefield. In contrast to most Patagonian glaciers, glaciological studies indicate that ...GPM has been advancing or remained stable during the 20th century. The advances periodically block Canal de los Témpanos creating an ice dam that impounds Brazo Sur–Rico arms of Lago Argentino, raising their elevations, until the water is released in a major outburst flood. Documentary evidence indicates that GPM reached the coast of Península de Magallanes for the first time in 1917. However, the first major damming and rupture event occurred in 1936, when the flooding of the shorelines of Brazo Sur–Rico killed thousands of Nothofagus trees, some still standing dead today. Naturalists who visited the area before 1936 described dense forests extending downslope to the shoreline, confirming the evidence of photographs from 1899 to 1928 displaying no standing dead trees by the shores. Estimates of the water level in Brazo Sur–Rico during each glacier damming vary but indicate values of 10–12 m for the 1936–1948 events and maxima of 23.5 m for the 1954–1956 ice dams. There is evidence for 21 ice dams between 1936 and 2013 with an average interval of c. four years from 1936 to 1988 and c. two years between 2004 and 2012. However, ring counts from standing Nothofagus dead trees along the flooded shorelines indicate that the oldest trees killed by drowning were at least 250 years old providing evidence of no major damming and rupture events from c. 1650 to 1936. These data indicate that damming and outburst events by GPM, world-renowned processes, did not occur for a long-term period before 1936. Unlike most glaciers in Patagonia, GPM was less extensive in the 1700s and 1800s than it is today.
The Patagonian Sublime provides a vivid, accessible, and cutting-edge investigation of the green economy and New Left politics in Argentina. Based on extensive field research in Glaciers National ...Park and the mountain village of El Chaltén, Marcos Mendoza deftly examines the diverse social worlds of alpine mountaineers, adventure trekkers, tourism entrepreneurs, seasonal laborers, park rangers, land managers, scientists, and others involved in the green economy. Mendoza explores the fraught intersection of the green economy with the New Left politics of the Néstor Kirchner and Cristina Fernández de Kirchner governments. Mendoza documents the strategies of capitalist development, national representation, and political rule embedded in the "green productivist" agenda pursued by Kirchner and Fernández. Mendoza shows how Andean Patagonian communities have responded to the challenges of community-based conservation, the fashioning of wilderness zones, and the drive to create place-based monopolies that allow ecotourism destinations to compete in the global consumer economy.
The Patagonian Sublime provides a vivid, accessible, and cutting-edge investigation of the green economy and New Left politics in Argentina. Based on extensive field research in Glaciers National ...Park and the mountain village of El Chaltén, Marcos Mendoza deftly examines the diverse social worlds of alpine mountaineers, adventure trekkers, tourism entrepreneurs, seasonal laborers, park rangers, land managers, scientists, and others involved in the green economy.
Mendoza explores the fraught intersection of the green economy with the New Left politics of the Néstor Kirchner and Cristina Fernández de Kirchner governments. Mendoza documents the strategies of capitalist development, national representation, and political rule embedded in the “green productivist” agenda pursued by Kirchner and Fernández. Mendoza shows how Andean Patagonian communities have responded to the challenges of community-based conservation, the fashioning of wilderness zones, and the drive to create place-based monopolies that allow ecotourism destinations to compete in the global consumer economy.
Ice elevation changes since 1975 and ice areal changes since 1945 of glaciers in the southeastern part of the Southern Patagonia Icefield (SPI) are presented. Comparison of digital elevation models, ...GPS, and optical survey data revealed high thinning rates for all the ablation areas of the glaciers, with average values between 1.4 and 3.4 m a−1 and maximum ice thinning of 7.6 m a−1. Ice elevation changes for the glacier accumulation areas were smaller than the estimated errors, and no significant trends could be detected. All the glaciers are retreating and shrinking considerably, with a total areal loss of 62.2 km2, which represents 8% of the total ice area of 1945. This trend is in agreement with other similar measurements carried out during recent decades for several glaciers of the SPI. The high thinning rates for the ablation areas of the SPI have been primarily interpreted as a result of the increase in temperature observed in the region, however, this warming trend is not large enough to account for all the ice thinning, indicating that dynamic factors could be important, especially in glaciers which have been thinning dramatically, allowing frontal calving fronts to reach nearly floating conditions. More measurements are needed to test and validate dynamic hypotheses related to glacier behavior in Patagonia.
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