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Two glacial deposits in the Gesso valley ( Maritime, Alps) have been 10 Be-dated at 20 140±1080 (weighted mean± SD) and 16 590±970 years, respectively, thus constraining the Last Glacial Maximum ( LGM) and Gschnitz stadials in the southwestern part of the Alps. The LGM age is chronologically coherent with MIS 2 and synchronous with most other LGM moraines in the Alps. The Gschnitz stadial also appears to be in agreement with the ages obtained from other Alpine sites and with Heinrich Event I. This suggests that the Alpine glaciers reacted simultaneously and essentially synchronously with the climate change associated with Heinrich Event 1. The Equilibrium Line Altitudes ( ELAs) of the LGM and Gschnitz reconstructed palaeoglaciers are 1850 and 1910 m a.s.l., respectively. The ELA comparison across the Alps indicates that the palaeoclimate of the Maritime Alps during the LGM was rather different from that of other Alpine sectors. However, the similar Gschnitz ELA value between the Gesso valley and other sites across the mountain chain indicates that Alpine glaciers responded with the same intensity to the climate change associated with Heinrich Event I. Overall, these results suggest that the interaction between the atmospheric circulation of air masses and local Alpine orography was more complex than has previously been argued. [ABSTRACT FROM AUTHOR]

In the southernmost tract of the Alps (Italian-French Maritime Alps), extensively covered by glaciers during the Last Glacial Maximum, about 30 small glaciers were present by the end of the Little Ice Age. The aim of this paper is to document the progressive decrease towards exhaustion of these glaciers, located at the latitude of 44° N, highlighting the factors affecting their retreat. All available data sources were investigated for this work including: the annual glaciers fluctuations record, comparative analyses of historical maps and multi-temporal oblique photographs and direct surveys in the field. The history of the Maritime Alps glaciers fluctuations was thoroughly reconstructed. Stationary conditions were observed from 1896 up to the beginning of the 1930s; since then they underwent phases of withdrawal with variable intensity. In the early 1990s, only six glaciers were still present, the extent of which were all was dramatically reduced. In the past two decades, the Maritime Alps glacier fronts experienced a global retreat of about 100 m, with a sharp acceleration after 2002. Currently ice patches along cirque walls and/or semi-buried lenses of ice are still present; morphological evidence of permafrost creeping in the glacier forefield accounts for the incipient transition to periglacial landforms (i.e. rock glaciers). The main factors controlling glaciers retreat seem to have been their original extent at the beginning of the current regressive phase and their distance from the main chain divide. From a climatic point of view unfavourable factors for glaciers persistence have been in the last decades a remarkable and sharp temperature increase, a decrease in winter snowfall and a shift of the rainfall peak from autumn to spring. [ABSTRACT FROM AUTHOR]

Four boulder samples from the Piano del Praiet frontal moraine in the Gesso della Barra Valley (Maritime Alps) have been 10Be dated. The results give a weighted mean age of 11 340±370 (870) yr, constraining the frontal moraine to the Egesen glacial stadial, during the Younger Dryas cold phase. By applying the same 10Be production rate to other Egesen moraines previously dated in the Alps, we obtain similar ages for all of them. This suggests a synchroneity of the Egesen deglaciation in the European Alps at the end of the Younger Dryas. From the palaeoshape of the Egesen glacier, reconstructed by means of geomorphological mapping, an Equilibrium Line Altitude depression (δELA) of −520 to −530 m, with respect to the present-day ELA, and of −260 to −320 m, with respect to the Little Ice Age ELA, has been calculated. Comparison with other Alpine sector δELAs indicates that the Maritime Alps experienced humid climatic conditions during the Younger Dryas. [ABSTRACT FROM AUTHOR]

Abstract: The proposed experimental study is aimed at contributing to the landslide susceptibility evaluation using a multidisciplinary approach: geological, geomorphological and geo-engineering survey, together with multivariate statistical analysis and GIS technique. It is included in a wider research project, aimed at defining the landslide hazard in the area of the map no. 250 “Castelnuovo di Garfagnana” (1:50000 scale). This study is based on the realization of a landslides inventory map and statistical data analysis using probabilistic methods. The methodology applied in ranking slope instability proceeded step by step. At first, geomorphologic investigation was performed in order to realize a landslide inventory map. A GIS database was created to collect the characteristics related to landslides geometry, type of movement and state of activity. Geo-engineering survey and characterization with in situ and laboratory tests allowed assessing Rock Mass Classification and geotechnical properties of soils (texture and consistency). The statistical approach for evaluating the landslide susceptibility is based on the assumption that the landslide probability for the currently landslides-free areas could be evaluated studying the conditions which led to past and present instability. A set of environmental factors, thought to be related to landslides, were analysed and their spatial distribution organized in different layers. Then, GIS-supported spatial analysis, conditional and multivariate analysis, allowed to calculate the connections between instability factors and landslide distribution. This step evolved towards two distinct statistical methods, both indirect and quantitative, leading to a classification of the land surface in some different susceptibility domains. Conditional analysis was applied to a particular type of terrain unit named Unique Condition Unit (UCU) that is a unique combination of the instability factors. The computer-aided evaluation of the landslide index within each UCU represents the probability of landslide occurrence, according to Bayes statistical concept. Multivariate analysis was applied to the same set of instability factors, but to a different type of terrain unit, the grid cell. The results showed a quantitative response, more reliable about the effectiveness of each instability factors, with the possibility of verifying their statistical significance. [Copyright &y& Elsevier]

The morphometry of 432 glacial cirques in the Maritime Alps (Western French-Italian Alps), studied over several years of fieldwork, was analysed with the use of a geographical information system. Some of the parameters automatically evaluated from digital elevation models required an objective and relatively new definition. In particular, cirque length was measured along a line that, from the threshold midpoint, splits the cirque into two equivalent surfaces; cirque width was automatically drawn as the longest line inscribed in the cirque and perpendicular to the length line. Significant correlations were found among the different factors and parameters analysed. In particular, cirque shape analysis showed that cirques develop allometrically in the three dimensions, i.e. more in length and width than in altitudinal range. Nevertheless cirques of the Maritime Alps have a regular, almost circular shape (meanL/Wvalue= 1.07). The correlations among length, width and area are all very high (r2= 0.8–0.9). In terms of size, cirques show a wide range in area from 0.06 to 5.2 km2 with a mean value of 0.4 km2. The largest cirques are found on SSW-facing slopes and at high elevations. Small cirques can be found at all altitudes but all those at high elevation are part of compound cirques at the main head valleys. Most cirques (37%) are characterized by a northern aspect; NE and SW are also frequent directions. [ABSTRACT FROM AUTHOR]

We combined data from geomorphologic surveys, glacial modelling, and 10Be exposure ages of boulders on moraines, to investigate the Last Glacial Maximum (LGM) and the early retreat glacial phases in the Stura Valley of the Maritime Alps. We used the exposure ages to reconstruct the timing of standstills or readvances which interrupted the post-LGM withdrawal, initiated ∼24 ka. We mapped and dated the frontal moraines of a first glacial standstill/readvance at a short distance (∼7 km) from the maximum external limit of the LGM, which occurred at ∼22 ka, and a second one at ∼19 ka (Bühl stadial). This morpho-chronologic succession is congruent with that obtained in the adjacent Gesso Valley and, combined with the similarity of Equilibrium Line Altitude values, demonstrates a consistent glacial response in the Maritime Alps to climatic forcing. Our data are chronologically consistent with those of the southern flank of the European Alps, stressing not only a general synchroneity of the LGM across the various sectors, but also that of a LGM recessional standstill or readvance at ∼22 ka. The short distance between the LGM moraines and the recessionary phase moraines, and minimal difference in ELA indicate a modest variation in the mass balance of the Maritime Alps glaciers during this time interval. A similar modest variation between LGM and the first recessional phase glacier mass balance is also found throughout the western sector of the Southern Alps but is considerably more pronounced for the glaciers of the central-eastern sectors. This behaviour can be explained by the interplay between the moisture supplied by southern currents sourced in the Western Mediterranean and that advected by the westerlies sourced in the North Atlantic, which affected the various sectors of the Southern Alps differently. • New LGM and early deglaciation dated in the Maritime Alps (southwestern Alps). • Modest glacial mass balance change between the LGM and post-LGM early stadials. • Maritime Alps climate was wetter than the central-eastern southern Alps. [ABSTRACT FROM AUTHOR]

Abstract: Along the rock coasts of the Gulf of La Spezia, which are characterised by a Mediterranean microtidal environment, a limited number of small rock platforms are scattered, constrained in elevation within 5m above present-day sea level. This work deals with a number of these rock platforms, formed in different rock types (one in limestone and two in dolomite), that show differences in their morphology. This paper aims to provide a quantitative examination of why there are morphological differences between platforms in this region. To achieve this purpose, factors controlling platform morphology and the processes acting on them are investigated through a comparative analysis of rock strength. Rebound values, obtained testing rock surfaces with the Schmidt hammer, were compared between different platforms and between different sectors of the same platform. Each platform was subdivided into two parts based on visual difference in rock surface colour, characterised by differences in occurrence of weathering microforms and bioerosive agents. Rebound values in the lower part of the platforms proved to be lower than in the upper part, providing quantitative assessment of the occurrence of weathering acting to different extents in the upper and lower part of the shore platforms (weathering degraded rock strength in the lower part by about 15%). It was demonstrated that on the upper part of platforms, displaying moderate evidence of physical and biological weathering, lithology significantly influences the rock strength. On the portion of platforms closer to sea level, instead, differential exposure histories of the same rock type in the same environmental setting can yield statistically significant variations in rock strength values. Thus, it is clear that in the lower part of the investigated platforms, the degree of weathering has strong bearing on rock strength, and that variations in rock strength are not solely due to lithology. According to the results of this work, experimental values of rock strength of platforms in the study area depend both on the rock type and on physical weathering due to frequently repeated wetting and drying and bioerosion. Lithology is then an important factor controlling platform shape and weathering is an important process operating on them. [Copyright &y& Elsevier]

The indentation index, which is the ratio between the real length of a coast and its Euclidean length, is a parameter applied to characterize rock coasts and to study their evolution. Rather than subjectively selecting two or more sectors of a rock coast, the method proposed in this paper considers analyzing the indentation index on the same coastline previously split into several adjacent tracts with equal Euclidean length. By digitizing the coastline in a GIS environment, it becomes possible to test several Euclidean length values on the same coastline, obtaining a different spatial variability of the indentation index with each trial. The best length values that maximize the spatial variability of the indentation index are those that determine an indentation index pattern characterized by high variance and low spatial autocorrelation. The spatial distribution of the indentation index can eventually be analyzed considering known littoral forces acting on the studied coast. When more than one Euclidean length value is found to maximize the variability of indentation index within the same coast, it is likely that there are one or more littoral forces acting or interacting differently at different scales. [ABSTRACT FROM AUTHOR]