1,721,089 research outputs found
The glacial history since the Last Glacial Maximum in the Forni Valley (Italian Central Alps). Reconstruction based on Schmidt's Hammer R-values and crystallinity ratio indices of soils
No full textKnowledge about deglaciation after the Last Glacial Maximum (LGM) in the mountain areas of the European Alps is still limited. In this study, we used Schmidt Hammer R-values (SH) and Crystallinity Ratio (CRF) indices of soils, together with historical data, to outline the glacial evolution of the Forni Glacier the biggest Italian glacier until some years ago, from the LGM to the present. The study area is in the Italian Central Alps, which has a well-known history after the LIA but many gaps before. By comparing results from the Forni Glacier and nearby Gavia Pass, we found that weathering rates may differ for the same lithology; therefore, SH requires a local calibration curve. A total of 6 different glacial phases were found in the study area before the LIA: 15 ka (phase I), 12.2 ka (phase II), 9.5 ka (phase III), 4.1 ka (phase IV), 3.2 ka (phase V), and 1.5 ka (phase VI). Phase I and phase II are common glacial phases in the Alps. Phase III was the biggest Holocene advance and the following were smaller than the LIA, accordingly to what happened in Triftjegletscher, a glacier on the northern side of the Alps with a similar catchment morphology. In the close Gavia Pass area, phase both phase III and phase V were larger than the LIA, suggesting that catchment morphology was more important than proximity for controlling Holocene glacial evolution. Interestingly, phase IV is rare in the Alps, but is contemporary to the 4 ka cold event. It was finally possible to identify the maximum of the LIA expansion in 1810 CE and this agree with recent studies that collocate one of the peaks of the LIA in the Alps in the first half of the 1800
Reconstruction of the glacial history after the Last Glacial Maximum in the Italian Central Alps using Schmidt's hammer R-values and crystallinity ratio indices of soils
No full textDespite the ongoing development of cosmogenic techniques to reconstruct deglaciation and glacial advances, these techniques are not always feasible for logistical and economic reasons. In this study, we used Schmidt Hammer R-values (SH) and Crystallinity Ratio (CRF) indices of soils, together with a limited number of absolute 14C dates, to outline the glacial evolution of the Gavia Valley. The study area is a sector of the Italian Central Alps with a glacial history that is poorly understood. Methodologically, we found that SH can be successfully applied to Late Pleistocene surfaces younger than 15ka in this Alpine region. The SH method generally underestimates the ages with respect to the CRF indices and the 14C dates. A total of 7 different glacial phases were found in the study area: 14.7ka (I phase), 13.7ka (II phase), 12.2–11.8ka (III phase), 10.2–9.7ka (IV phase), 7.5ka (V phase), 5.5ka (VI phase), 1.9ka (VII phase). These phases are generally consistent with the literature; however, the Little Ice Age was surely less extended respect the other Holocene advances (V and VI phase). This suggests that relatively short climatic variations during the Holocene were locally important
Evolution of the sparse debris cover during the ablation season at two small Alpine glaciers (Gran Zebrù and Sforzellina, Ortles-Cevedale group)
No full textDespite the increase of sparse debris on many glaciers in the world and its undisputed impact on glacier ablation, both its evolution and its detailed effect have been poorly investigated yet. In this study we evaluated the evolution of the sparse debris cover during the ablation season at two small glaciers of the Ortles-Cevedale group (Central Italian Alps, Italy), the eastern tongue of Gran Zebra glacier and Sforzellina glacier. We investigated the different effects of the sparse debris on albedo, on the glacier surface temperatures (using ground-based thermal imaging) and on ablation. The supraglacial debris cover increased three times faster at Sforzellina glacier, both in terms of mass and percentage debris cover, with a mean debris coverage rate of 621 g/m2 per day and a percentage of 2.07% per day, with respect to Gran Zebra glacier. As debris accumulates on the surface mainly by melt out of englacial debris, the debris coverage rates depend both on the ablation and on the englacial debris concentration, which was found to be higher at Sforzellina glacier (mean 10,810 g/m3) as compared to Gran Zebra glacier (mean 6131 g/m3). Debris is mainly composed by clasts coarser than 25 mm at both glaciers (ca 90%), with subangular sedimentary rocks prevailing at Gran Zebra and angular metamorphic rocks at Sforzellina glacier, suggesting a debris supply from the rockwalls surrounding the glaciers, with a longer englacial transport at Gran Zebra. Albedo decreases at increasing percentage of debris covering the surface, linearly at Sforzellina and logarithmically at Gran Zebra and surface temperatures are positively correlated with the mass of debris present on the glacier surface. The influence of the percentage of debris on the mean ablation rate is explained by a quadratic function, with the ablation rate increasing at increasing debris cover for moderate debris covers, due to the decreasing albedo, and decreasing ablation rates with high percentages of debris cover (>80%), due to the insulation effect of clasts
Using ground-based thermography to analyse surface temperature distribution and estimate debris thickness on Gran Zebrù glacier (Ortles-Cevedale, Italy)
No full textIn this paper we used ground-based thermal infrared imaging to investigate the spatial variability of surface temperatures on a mountain glacier at high spatial resolution and to estimate the supraglacial debris thickness distribution. The surveyed area is the eastern tongue of Gran Zebrù glacier, a small mountain glacier of the Ortles-Cevedale group (Italy). A FLIR E85 Thermal Camera was used to obtain a panoramic thermal image of the glacier surface on 30 September 2019 that was calibrated and georeferenced in order to obtain surface temperatures. Based on field data, debris thickness and debris surface temperature were correlated by using an exponential equation. The equation was used to estimate debris thickness on the glacier from the temperature data. The results show a spatial variability of surface temperatures, with the lowest temperatures found on snow and ice surfaces, and the highest on supraglacial debris. The estimated debris thicknesses show an inhomogeneous distribution, with a calculated mean debris thickness of 0.09 m in the areas of continous debris coverage. We found a good correspondence between measured and estimated debris thickness at 30 validation points (RMSE = 0.04 m and r = of 0.92). We demonstrated that ground-based thermal imaging can provide very high resolution maps of glacier surface temperatures and of debris thickness that can be used for the estimation of glacier ablation, with a spatial resolution more suitable than that offered by satellite data, especially for glaciers with a small area and with a heterogeneous surface
Climate change and rapid ice melt: Suggestions from abrupt permafrost degradation and ice melting in an alpine ice cave
No full textAmong the different elements of the mountain cryosphere, ice caves still represent the lesser known part of it. Here we present a seven-year-long record of air and rock temperature in a cave of the southeastern European Alps. We demonstrate how the presence of a permanent ice deposit in the cave is not only related to the net cooling effect of the air circulation, as it is well known, but also to the occurrence of relict permafrost. Through a detailed representation of temperature patterns inside the cave, both air and rock data show how after a period of perennially subzero (cryotic) conditions in the rock, ongoing anthropogenic climate warming is responsible for permafrost degradation despite the cooling effect of the air circulation in the cave. Data support the important role of cryotic conditions in the rock in preserving a permanent ice cave deposit in the present climate, even once the possible relict permafrost inherited from the past disappears. A thickness of 29–44 m of permafrost, possibly formed during the Little Ice Age, has now almost completely disappeared. The present abrupt ice degradation observed in this cave is further exacerbated by positive feedbacks related to warmer air circulation in the cave system
Rock glaciers inventory of the Italian Alps. Rhaetian A. Catasto dei rock glacier delle Alpi Italiane. Alpi Retiche
No full textInterest in rock glaciers has a long-standing tradition in ltaty. Harmann, Nangeroni and Capello pioneered work on this type of landfonn in the Wesfem and Central Alps,
starting from the mid 19205; this work was continued until the end of the 19505. After
that time. in other countries indepth research continued and developed beyond the
already completed descriptive phase, whereas in Italy specific research on this topic
was no longer being done. It was only at the start of the 19805 that within the scope of
work being done by the Glaciology Section of the Gruppo Nazionale Geografia Fisica e
Geomorfologia (National Group on Physical Geography and Geomorphology) of the
Consiglio Nazionale delle Ricerche (National Research Council), thanks to the efforts of
G.B. Casliglioni, interest in these landforms so characteristic of the morphoclimatic
periglacial and glacial domain, was renewed once again. This interest was then
transformed into the energetic activity of all of the members of the Sector as regards
the preparation of the inventory presented here
Psychodrama with women who are victims of violence: an international project
No full textThe EMPoWER research project we are introducing here has been conceived within the framework of the European Daphne initiatives and has already completed the first preliminary organisation opening in the activities promoted during Fepto meetings between 2009 and 2010. The initiative is the second part of a research, already accomplished and directed by Ines Testoni titled “mafia's psychism and female corporeality management1”, whose main objective was to understand what are the psychological and social factors exposing woman to the trade of the international prostitution market. The achieved results demonstrate that in several traditionalistic areas, where the family relationship are matrifocal and the social culture is patriarchal, the international mafia gets rich intercepting women and treating them as commodities for sex and servitude trade. It is emerged amongst the main causes of this phenomenon that in the generation mandate between mother and daughter the women’s masochistic attitude towards men is kept unchanged over the centuries. The subordination is a relational mode that the mother teaches to the daughter, demanding her to assimilate it
Radiocarbon dating of the Postglacial morphologic evolution in upper Valtellina and Livignese area (Sondrio, Central Alps)”,
No full textThe use of iron chemical analysis of podzols to date the Late Pleistocene–Holocene deglaciation history of the Central Italian Alps
No full textPodzols that have developed on glacial and periglacial features provide the opportunity to reconstruct glacial evolution after the Last Glacial Maximum (LGM) using different soil indices. Analysing 17 soils classified as podzol, we used the crystallinity ratio of free iron oxides (CRF) on both the A and Bs horizons, and absolute ages for the same landforms containing the soil profile, to create dating curves. Two equations were generated: age = 4566.9 × ln (CRF) + 1760 (1), and age = 3907 × ln (CRF) + 3508.2 (2). The reliability of the curves was evaluated with the Feo/Fed ratio, and with the difference of ages calculated using both equations. Equation (2) is considered more reliable because the A horizon may be influenced by new pedogenesis on the pre-existing podzol, leading to the development of a new type of soil. By dating the soils, we reconstructed the glacial history of the three main upper branches of the LGM Adda Glacier in the Central Italian Alps, specifically the Stelvio Pass area (ST), Gavia Pass area (GV), and the Val Viola valley (VV). Seven glacial advances were identified at 16.7–14.7 ka (phase I), 12.3 ka (phase II), 11 ka (phase III), 10–9.7 ka (phase IV), 9 ka (phase V), 7.5 ka (phase VI) and 5.3 ka (phase VII). The first five phases are chronologically similar to the main Late Pleistocene–Early Holocene phases recorded in the Central European Alps. The last two Holocene phases, which are both longer in duration than the Little Ice Age, are recorded in ST and GV. Interestingly, these phases generally are not recorded in the rest of the Central European Alps, where the late Holocene glaciers were smaller than their present size
apporti tra vegetazione e permafrost discontinuo in ambiente alpino. Val Vallaccia (Livigno, Sondrio)
No full textanalisi dei rapporti tra vegetazione e permafrost discontinuo sulle Alpi centrali Italiane
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