421 research outputs found

    Multitemporal dendrogeomorphological analysis of slope instability in Upper Orcia Valley (Southern Tuscany, Italy)

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    The Upper Orcia Valley (Southern Tuscany, Italy) is a key site for the comprehension of denudation processes typically acting in Mediterranean badlands (calanchi) areas, thanks to the availability of long-lasting erosion monitoring datasets and the rapidity of erosion processes development. These features make the area suitable as an open air laboratory for the study of badlands dynamic and changes in geoheritage due to erosion (i.e. active geomorphosites). Decadal multitemporal investigations on the erosion rates and the geomorphological dynamics of the study area allowed to highlight a decrease in the average water erosion rates during the last 60 years. More in detail, a reduction of bare land and, consequently, of erosion processes effectiveness and a contemporary increasing frequency of mass wasting events were recorded. These trends can be partly related to the land cover changes occurred in the study area from the 1950s onwards, which consist of the significant increase of reforestation practices and important other forms of human impacts on slopes, mainly land levelling for agricultural exploitation. In order to better identify the most significant phases of geomorphological instability occurred in this area during the last decades, an integrated approach based on multitemporal geomorphological mapping and dendrogeomorphology analysis on specimen of Pinus nigra Arn. was used. In detail, trees colonizing a denudation slope located in the surrounding of the Radicofani town (Tuscany, Italy) and characterized by calanchi and shallow mass movements deposits, were analyzed for the 1985-2012 time period. The analysis of the growth anomaly indexes and of compression wood allowed to determine a spatio-temporal differentiation along the slope and respect to an undisturbed reference site. The negative anomaly index results to be more pronounced in the trees located on the investigated slope with respect to the ones sampled in a non-disturbed area. Compression wood characterizes trees on slope sectors mainly affected by runoff and/or mass movements with a different persistence. Erosion rates were finally calculated through dendrogeomorphological analysis on tree roots exposure (0.31-3 cm/y runoff prevailing; 5.86-27.5 cm/y, mass movements prevailing). Dendrogeomorphological results are in accordance with those obtained in the investigated areas with multitemporal photogrammetric and geomorphologic analyses

    Signals of 20th-century warming from the glaciers in the Central Italian Alps

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    The Lombard Alps in the central sector of the Italian Alps are one of the most intensively glacierized regions on the southern side of the chain (about 113 km2 of ice cover). All of the glaciers have been retreating since the beginning of the 20th century, but the trend is not uniform. Since the 1950s there has been a drop in the percentage of retreating snouts and an increase in stationary and advancing snouts. After 1985 the glaciers in the Lombard Alps began a new recession phase that is still going on. This pattern is consistent with temperature variations in Lombardy in the 20th century. According to data from Sondrio station, four alternating warming and cooling phases ran be distinguished in 20th-century warming. The Lombard glaciers well recorded the last three phases, showing evident signs of the 1955–88 cold phase, with a response time of about 20 years, and may be considered good indicators of 20th-century temperature trends

    Multi-temporal mapping of the Upper Rhone Valley (Valais, Switzerland): fluvial landscape changes at the end of the Little Ice Age (18th–19th centuries)

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    The Upper Rhone Valley (Valais, Switzerland) has been heavily modified over the past 200 years by human activity and natural processes. A qualitative analysis of the morphological and land- use evolution of the Rhone River floodplain since the end of the eighteenth century was carried out using historical maps from 1780 to 1860 processed with Structure-from-Motion (SfM) and Geographical Information System (GIS) tools. This study aims to produce a long-term analysis of river management and land-use change in a stretch of the Upper Rhone Valley around the town of Sion based on a time series of maps, realised in the years 1780–1802, 1820–1845, 1847, 1850s, 1852–1857, 1859–1860. The historical maps were digitised, and for each of the corresponding periods, a map was produced within a GIS. The comparison of the maps was completed by using documentary sources or subsequent studies. With the intention to identify the fluvial landscape changes and past river management, six multitemporal maps were produced. Finally, this research aims to provide helpful diachronic information for planning a future sustainable landscape development in Valais

    Assessment and selection of geomorphosites and trails in the Miage Glacier Area (Western Italian Alps)

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    Glacial environments are considered geomorphosites because they exhibit all of the features that characterise sites of geomorphological interest. The Miage Glacier, in particular, is the most important debris-covered glacier of the Italian Alps, and it has been extensively studied since the 18th century because of its scientific features. In this area, the geomorphological and geological attributes are evaluated at 11 sites that have been individuated along the three main touristic trails, which allow an exploration of the surroundings of the glacial tongue and its two main lobes. Using a methodology previously tested in a fluvial environment, single sites and trails are quantitatively assessed to determine the most suitable trail for educational purposes. Hazards that could potentially affect the trails are considered in terms of both risk education and final selection of the most suitable trails for the various possible user groups. The richness of scientific data in this area should increase its importance as a geomorphosite by increasing the educational value of the Miage Glacier and the Veny Valley

    Posibilidades de la integración latinoamericana en condiciones de escasa interdependencia

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    This article aims to assess the real possibilities of Latin American integration taking into account the conditions of low interdependence among our countries since the Colonial Era. The realistic exercise does not hinder, however, the identification of at least one area of concrete interdependence and relevant in what the region has to offer the world, which is energy and the provision and conservation of natural resources. Based on the recognition of the vulnerability of those resources and on the normative horizon of “relational autonomy” the commitment to energy integration as a strategy of a structural and concrete integration can not only serve as a basis for sustainable economic growth, but for creating a strong political alliance aiming for a more stable and predictable integration.Este artículo tiene por objetivo evaluar las posibilidades reales de la integración latinoamericana teniendo en cuenta las condiciones de escasa interdependencia entre nuestros países, que se remontan a la época colonial. El ejercicio realista no impide, sin embargo, identificar al menos un área de interdependencia concreta y relevante, vinculada a aquello que la región tiene para ofrecer al mundo: la energía y la provisión y conservación de recursos naturales. Es desde el reconocimiento de la vulnerabilidad de esos recursos, y con el horizonte normativo de la “autonomía relacional”, que la apuesta por la integración energética como estrategia de integración estructural y concreta puede no solo servir de base para un crecimiento económico sustentable, sino también para la creación de una fuerte alianza política que sea fundamento de una integración más estable y previsible

    Eugenio Tironi, Apología de la Intuición, Ariel, Santiago de Chile, 2014, 399 p.

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    Uno de los objetivos del libro es ofrecer respuestas a la supuesta crisis de confianza respecto a las instituciones, la clase política y las élites en general; o bien, como dice el subtítulo, “cómo comprender el desprestigio de la democracia y la empresa”. Buena parte del problema, según el autor, se debe a que las respuestas frente a esta crisis siguen haciendo como si nada hubiera cambiado de fondo, como si se tratara de meros ajustes, de una mejor gestión de lo existente y de la búsqueda d..

    Water driven processes and landforms evolution rates in mountain geomorphosites : examples from Swiss Alps

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    Geomorphic processes driven by water are particularly active in mountain environments, especially under the current climate conditions. Erosion and dissolution processes shape meaningful landforms, in different kinds of deposits and rocks, and in some cases they are classified as geomorphosites. Such landforms, especially earth pyramids and rock pillars, are usually characterized by a high scientific value (e.g., representativeness, ecologic support role) and by additional values (e.g., cultural and aesthetic value) contributing to the local geoheritage. Mountain geomorphosites are growing in importance within scientific community and their morphological evolution can affect the global value of the site itself (e.g., integrity). In this paper, after a first review on the terminology used for classifying landforms modelled by water runoff and on their meaning within the mountain environment, the results of a detailed research performed at two sample sites, included in the Swiss National Inventory of Geosites, are presented. The two study sites are representative respectively of: i) water runoff on glacial deposits shaping earth pyramids (Pyramides d'Euseigne); ii) water dissolution on gypsum rocks, modelling articulate karst landscapes (Pyramides de gypse du Col de la Croix). For each site, landforms evolution was investigated and denudation rates were estimated by means of different methods: iconographic material analysis, quantitative geomorphology and dendrogeomorphology on exposed roots. Despite the long-term, average rates obtained by means of roots exposure for both water runoff on glacial deposits (e.g., 5.8 mm/y) and dissolution on gypsum rocks (5.6 mm/y) are comparable. Moreover, a strict relation between the activity degree of processes, the integrity of the site and the assignment of geomorphosites to a specific category (i.e., active, passive or evolving passive) emerged from the results
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