Supplementi di Geografia Fisica e Dinamica Quaternaria

Analyses of selected samples coming from a well exposed plio-pleistocenic stratigraphic section located along the coastline of northwestern Sardinia, allow us to evaluate the recent geomorphological evolution of a sector belonging to an ancient valley infilled by sedimentary deposits, mainly of continental environment. The palaeovalley filling has been favored by erosional processes in post-Tyrrhenian regression times under climate exchange recorded during Holocene. The occurrence of halite mineral phase in the studied stratigraphic sequence, suggests the prolonged occurrence of salt environments during the early phase of post-Tyrrhenian regression before the begin of an aeolian regime. Assuming a uniform erosive process for the last 80 Ka, we evaluate its the efficiency on the basis of the volume of deposits infilling the investigated palaeovalley. The obtained deposition rate is about 0.5 m<sup>3</sup>/year.
Cores obtained from boreholes drilled in the town of Como are composed of glacio-lacustrine sediments covered by fluviatile gravel of local provenance. A layer of black sand at the base of the gravel contains wood, from which a 14 C age of 11 730 BP has been obtained. This is a first minimum age for the complete deglaciation of the Lake Como basin. -from English summary
Taking into consideration the available documentation (maps and literature), a tentative is made to outline the evolution of Ghiacciaio Nord delle Locce since 1854. The unit examined is the third largest glacier in the Ossola valleys (within the Italian border); however the glaciological information on it has been scarce and unsatisfactory until the investigations of VAW/ETH, following to the outburst of Lago delle Locce in 1979. Some geographical information on the present Ghiacciaio Nord delle Locce, together with its glacial deposits, is first given. Then the map sources on which a part of the present investigation is based are carefully and critically reviewed, stressing on the problem of elevations. As no precipitation data for the upper, glacierized Valle Anzasca are available, some data from the ENEL dams in neighbouring Valle Antrona are presented: they show that there is a continuous decrease of precipitations since 1978, causing the present glacier retreat after a short time span of steady state and even short glacier advance. The available literature concerning Ghiacciaio Nord delle Locce is then critically reviewed and the investigations of the glaciologists of the VAW/ETH of Zurich, Switzerland, on Lago delle Locce and Ghiacciaio Nord delle Locce, are also recognized. Among the glaciological results of this research program, we underline the assessment of the dynamical behaviour of Ghiacciaio Nord delle Locce after sinking of Lago delle Locce level. A final section describes the present terminal and confluence condition of the investigated glacier.
The theme of the conference, held at Como, was 'The upper Pleistocene in Italy'. The first 5 papers give a description of various aspects of the Wurm in northern, piedmont Italy; 6 papers discuss the upper Pleistocene in Italy as a whole; the final 3 contributions are papers delivered at the conference. Citation details of the individual papers are entered on our machine-readable bibliographical database. -M.A.Bass
In July 2003, during a dry period, debris flows occurred on the large , polygenic fan (0.85 km2; elevation difference of 500 m) at the foot of the Glacier de Frébouge (Val Ferret). These events deeply incised the western fan sector and deposited ∼ 30000 m3 of coarse material in the distal part of the fan. The first debris flow on 17 July may have been triggered by a glacial water pocket outburst flood, a nor uncommon process in the Mont Blanc massif. The other ones developed in three steps: (i) ice avalanching of a part of the Glacier de Frébouge front; (ii) damming of the proglacial torrent gorge by the ice deposit; (iii) outburst flood due to dam collapse, with debris flow formation. Increasing ice avalanching at the hanging front of retreating glaciers constitutes an important natural hazard factor in alpine high mountain tourist areas.
False colour composite (RGB: TM5, TM4, TM3) of Landsat image for the year 2003. 
The map of classes identified on the image of year 2003. 
This paper presents the results obtained from the analysis of one recent Landsat TM image for the study of the status of some glaciers on Eastern Italian Alps. Then these results are compared with a set of multitemporal Landsat images from the Eighties. A fuzzy set based classification technique permitted to quantify snow and exposed ice extents in glaciated areas. Integration with topographic information allowed to derive the elevation of glacier terminus, although the result is overestimated due to some problems with digital elevation data and frontal debris coverage. A comparison of front altitude changes data derived from satellite image processing with elevation measured during field surveys supports the knowledge of the size of glacier reduction of the last decades. On Aurine and Pusteresi Alps glaciers, the changes in the last twenty years result to be a reduction corresponding to the 40% of the glaciated surface in the '80s, but a lot of the glaciers are now characterized by a new extent debris coverage in the frontal zones.
Crevasse splays caused by the flood event of December 2003 in the Rhône Delta (Mediterranean France) offered the opportunity to study the «stage I» of Smith & alii (1989), as contemporary analogues for quantifying lateral erosion and overbank deposition in the flood plain. From two study cases («Petit Argence» and «Claire Farine»), main hydrogeomorphological impacts of December 2003 flood event and sedimentary facies associated with each crevasse-splay sub-environment (crevasse channel, crevasse-splay lobe, proximal and distal flood basin) are detailed. Fluvial landforms, sediment-body geometries and sedimentary-facies characteristics are determined using a combination of topographic maps, remote sensing data, field measurements, and laboratory analyses. Spatial distribution of hydraulic parameters such as mean flow velocity, bed shear stress, and specific stream power is derived from relationship with mean flow depth, sediment structure, sediment grain size, sediment thickness, and distance from the Petit Rhône channel/dyke breach. Sedimentological analysis highlights different gradients of downstream thickness, fining, and sorting of sediments. The 3-D geometry of crevasse splays is reconstructed with calculation of the sedimentary volume deposited or eroded in the delta-plain area. Sediment balance (674,227 ± 33,711 m3) derived from December 2003 crevasse splays is correlated with the delta-plain sediment balance.
The marine and transitional terrains extensively cropping out near Varda were studied and dated through Th/U measurements on corals. The dates range between 103 and 209 Kyr BP indicating a Tyrrhenian age for the entire sequence. From their areal distribution, the deposits appear to belong to three distinct transgressive cycles in onlap relations. Their ages substantially correspond on the well known 5.3, 5.5 and 7.1 isotopic sub-stages. -from Authors
Tectonic analysis is a fundamental tool to understand kinematics and behaviour of active faults, and to assess of the seismic risk of an area. Structural-geological and morphotectonic analysis of the Monte Sant'Angelo fault clearly indicate it to be active. Detailed measurements of the morphology of the mountain slope and of the cumulative scarp allowed to kinematically characterize this fault with a vertical slip rate of 0,7 ± 0,2 mm/yr and a right-lateral slip-rate of 1 ± 0,2 mm/yr. Evidence of cumulated coseismic surface ruptures have been recognized along the main fault trace, and it was even possible to estimate a maximum magnitude of M = 6,9 and a recurrence time of 1860 ± 460 years for such earthquakes. Historically, similar earthquakes are not documented on this fault, and the area is in fact classified with a maximum felt intensity of VII-VIII MCS. Nonetheless, a strong earthquake at Monte Sant'Angelo is described in one of the most important medieval sacred legends, and traditionally dated around the 5(th) century A.D. By combining tectonic, archeological and historical data, the most recent of the observed faulting events could be identified as the possible result of the earthquake reported in that legend. The main results of this study are therefore: 1) identification of a strong italian earthquake (6<M<7) in the Roman-Middle Ages period, as well as of its epicenter; 2) determination of the kinematic and seismological parameters of the active fault implied in that earthquake; 3) individuation of its possible coseismic surface rupture. An interesting observation arises also from the recognition of some secondary fractures which, due to their particular location and shape, may have been interpreted as 'the footprints' of Archangel Michael, whose descent was believed to be the cause of the earthquake.
Several ice caves have been discovered in the Pyrenees. Among them, cave A294 hosts one of the most interesting ice deposits, which is mainly composed of firn ice. This paper investigates the present-day climate dynamics and the isotopic composition of precipitation, dripping water and ramp snow) to evaluate the palaeoclimatic potential of the ice cave deposit. The cave experiences a chimney effect during the winter but acts as a thermal trap during the summer. Four climate phases with mean annual temperatures ranging from -0.77 to 0.26°C have been interpreted along the year. At present-day conditions, even though some congelation ice forms annually, the ice has a negative mass balance with an annual ice loss of ca. 12 m3 that mainly affects the walls of the ice deposit. The seasonal variability of the stable isotopic (δ18O and δD) composition of dripping water and ramp snow has a smaller amplitude compared to that of the precipitation (rain and snow). The data show a good correlation (r 2=0.94) and match the Global Meteoric Water Line. We hypothesise that the metamorphosis of snow into ice causes no significant postdepositional alteration, and thus the ice from cave A294 may be used as a reliable palaeoclimatic archive. Given the reduced volume of ice deposits in the region and their rapid melting, it is extremely urgent to study the ice record in cave A294.
On September 26 th 2005, Italy's first Automatic Weather Station (AWS) was set up on the melting surface of a glacier (Forni Glacier, Upper Valtellina, Stelvio National Park, Lombardy Alps). The AWS (named AWS1 Forni) is equipped with 12 different sensors to collect data on the main atmospheric parameters serving to describe the glacier boundary layer. The data collected during the first year of operation are presented in this paper, along with some preliminary comments. The results obtained are consistent with those from other AWSs located around the world on the melting surfaces of glaciers, thus underlining the correct selection of the location for this AWS and proper operation of the instruments. The analysis of incoming and outgoing radiation permitted the quantification of the albedo values: c. 0.7 for snow and c. 0.3 for ice, with an annual value of 0.417 and thus only c. 21 % of the solar radiation available at the top of the atmosphere being absorbed by the Forni Glacier surface. The snow pit stratigraphy was found to match the instrumental snow level record very closely.
Several studies carried out previously on the Gran Sasso Range and nearby (Monti della Laga) in Province of L'Aquila (Abruzzi, Italy) noted qualitative relationships among the rock fracturing degree, and the karst landforms. This research deals with the identification of more detailed relationship between some geo-strucrural and morphologic elements and karst features. The rock fracturing conditions of carbonat e formations are like to increase the karst processes by the forming of preferential way for penetrating waters. A comparison between jointing class and surface karst landform was carried out using a standard GIS approach (ILWIS). T he results showed a significant inverse correlation between jointing density classes and the karst polygonal features. Moreover by combining the geostructural information with the karst landform. occurrence, the AA. conclude that: the faults occurrence and proximity are like to increase both the jointing density and the fissure permeability of the carbonate rocks; the high degree of rock jointing is favouring a rapid water penetration so hindering more complex karst landform genesis. Some petrographic observations suggest that the hard limestone are showing more micro-stress features than softer ones.
The National Park of Gran Sasso-Monri della Lags (Abruzzo, Central Italy) is representative of a mountainous Mediterranean environment, with a range of elevation from 800 to 2900 meters above sea level and commonly occurring landslides, particularly in the northern belt of the Park. Two main geological formation groups are predominant in the area: the oldest one (of the Trias to Miocene periods) consists of marine carbonate rock formations, which have been tectonically overthrusted by more recent siliciclastic formations during the last orogenetic phase of the Central Appcnnines (Upper Miocene - Lower Pliocene); these are formed mainly by sandstone and marlstone of the Miocene age and bear the name Flysch della Laga. The research carried out on a pilot area of the Park was addressed to obtain a small scale mapping of both distribution and intensity of the slope instability factors. This was accomplished by considering the percentage occurrence of some instability factors, as the ratio of friction-angle to layering dip-angle less than 1, and the occurrence of morphological signs of instability as active talus. The resulting map (IFP) which could be interpreted as expression of potential susceptibility to slope instability, was not similar to a previous instability hazard map of the same area made by traditional parametric methodology. Instead the IFP map compared with actual distribution of instability phenomena (landslides, badlands, active scree deposits, etc.) over the same area resulted positively correlated at 0.99 probability level. The proposed method seems to be able for predicting the susceptibility to instability trend not only over whole territory but also in areas assumed after traditional methods to have homogeneously distributed hazard class.
Results obtained for the River Sinello drainage basin, emplaced in a lithologically variable and structurally complex area. The morphological pattern of the basin seems to be controlled by some tectonic directions, among which N-S, E-W, NE-SW, and NW-SE are especially outstanding. The NW-SE, NE-SW and E-W directions seem to have acted in the most ancient time; the latter, however is likely to have been reactivated, as it clearly controls, together with the N-S trending tectonic line, the very recent evolution of the drainage network. These processes are particularly evident and widespread in the mountain sector, also due to strong tectonization. Particularly active is denudation on slopes, mainly consisting of landslides, often of remarkable size. The hypsometric analysis made it possible to define accurately the areas which are affected by intense morphogenetic processes. Markedly downward convective curves show that fluvial deepening is the dominant processes in the partial basins of the Sinello headwater.
The geomorphologic study and cartography of the summit area of the Gran Sasso d'Italia are presented. The area is located between the Corno Grande and the Corno Piccolo. The area also contains a geomorphologic rarity, the Ghiacciaio del Calderone, the southernmost glacier in Europe and the only one in the central-Mediterranean area. The present geomorphological scenario was mainly created by glacial processes. Gravitational processes, together with running waters, karst, cryogenic phenomena and human activity have not been of major importance in shaping the present landscape. The survey data have been collected, georeferenced and analysed in a GIS (Geographic Information System) environment and the principal graphic output is represented by a geomorphologic map. Particular attention has been paid to the graphic and informative solutions proposed in order to describe interacting processes and landforms both at the spatial and temporal level.
A few km far from the confluence of the Fioio Valley into the Carsoli basin, some hundreds m2 wide and ca. 1.5 m thick carbonatic deposit is present, embedded within late Middle Pleistocene alluvial gravels. The deposit formation might be related to sub-aerial deposition of CaCO3 (tufa) from emerging groundwater. A U/Th dating to 46 ± 6 ka BP constrains the deposit within the MIS 3, corresponding to a phase of warming between the MIS 4 and 2.
The strong influence of nature on human life during ancient times requires that people must have chosen their habitats based on the limits of their technology, especially of farming technology, and an understanding of natural conditions. To verify this assumption, the correlation between natural environment and habitat placement in the Daegu basin in Korea over the recent Holocene has been investigated. In this paper, we attempt to correlate various changes in the natural environment of the Daegu basin with the location of burial sites, cultivated fields, and residential areas during the Bronze Age, the Iron Age, and the proto-Three Kingdoms Age. We also compared the changes in location and extent of inhabited areas to the development of tools, soil characteristics, and to the climatic changes based on the sea level changes during the Holocene. We conclude that people probably did limit their habitats according to their understanding of their environment and their technology.
During the last two decades a renewed interest emerged in the scientific community for geoheritage, geoconservation and geotourism research. This was the reason for the International Association of Geomorphologists (IAG) for creating a specific working group (WG) on geomorphosites, that is the geomorphological part of geoheritage, in 2001. This paper reviews the main improvements made in the field of geomorphosite research during the period 2001-2012. A first domain of research concerned conceptual studies, in particular the definition of geomorphosites and the question of their value, as well as the links between geomorphological heritage and geodiversity. Some members of the WG also developed specific methods to assess geomorphosites and proposed guidelines for their mapping and the realisation of geoproducts. The work carried out during the last decade allows us to propose new perspectives, in particular on scale issues, the relationships between geoheritage and geodiversity assessment, the elaboration of guides of practices, and the integration with other disciplines (social and educational sciences, computer sciences, process geomorphology).
The paper describes the erosion processes acting at La Fossa cone (Vulcano Island, Italy). La Fossa cone is a stratovolcano made up of pyroclastic deposits and lavas covered by tuffs from the last eruption, dated 1888-90. Its flanks are affected by intense water erosion phenomena leading to the formation of denudation surfaces due to sheet erosion, rills, gullies and small canyons. As a consequence of very intense rainfalls, episodic debris flows occur along main gullies and canyons. Fumarolic activity plays an important role in the control of erosion processes, being both an obstacle for the growth of vegetation and a weathering factor. The GIS analysis and comparison of geo-referenced maps and aerial photos highlighted the influence of man-made structures on erosion processes, with particular reference to deep modifications in the natural stream network induced by buildings and roads. The combined effects of volcanic and anthropogenic activities, together with the additional role played by the strong inter-annual variability of rainfall amounts and intensities, give rise to significant changes in water erosion rates. A total volume of 5,700 m3 of volcanic products eroded between the years 1980 and 2008 from the upper portion of La Fossa cone has been estimated by GIS analysis.
Sezione geologica schematica della morena L3 (rn) (per l'ubicazione v. fig. 2). R = roccia. In evidenza le date 14C espresse in anni B.P., non calibrate, con le relative sigle di laboratorio.
Geomorphological, glacial geological, lichenometrical and dendrochronological studies have been carried on the Upper Val di Genova with the aim of reconstructing Holocene fluctuations of the Vedretta della Lobbia. The maximum extention reached by the glacier during the Little Ice Age is marked by a moraine near the Malga Matarot bassa, at about 1790 m. The age of this moraine lies between 1645 A.D. and 1845 A.D. The maximum position of the same glacier during the Holocene has been determined at a slightly more advanced point (before 5310 14C yr BP). An end moraine located about 100 m South of the Malga Matarot bassa, at about 1790 m, marks the position reached by the glacier in the second half of the last Century. In the 20th Century, the Vedretta della Lobbia gradually retreated to its present position at about 2570 m. When the galcier was at its maximum position during the Little Ice Age, the snowline was situated about 60 m below the present snowline (2950). -from English summary
Two active rock glaciers occur in the eastern and northeastern cirques Cadin del Ghiacciaio and Cadin di Croda Rossa at Croda Rossa in the Eastern Dolomites, South Tyrol (northern Italy). Both rock glaciers display a tongue-shaped morphology with typical surface morphology of transverse ridges and furrows. The rock glaciers are composed of limestone and dolomite debris derived from Upper Triassic and Lower Jurassic carbonate rocks. Compared to rock glaciers of regions with metamorphic bedrock the debris of both rock glaciers is finer grained and the surface morphology is less well developed. Due to the karstified bedrock beneath both rock glaciers almost all meltwater is released along karst cavities and there is almost no surface discharge. The thermal regime within the debris layer is strongly influenced by the local weather conditions. Ground temperatures are significantly lower than on permafrost-free ground outside the rock glaciers. Annual flow velocities are low compared to other rock glaciers, ranging mostly between 5 and 20 cm. Internal structures (shear planes) interpreted by georadar data, flow velocities and particularly ice exposures at the upper part of Cadin del Ghiacciaio rock glacier clearly indicate that this rock glacier developed from a debris-covered cirque glacier and is under permafrost conditions still today. We suggest that Cadin del Ghiacciaio rock glacier has developed from a small avalanche-fed cirque glacier during retreat through inefficiency of sediment transfer from the glacier ice to the meltwater. Cadin di Croda Rossa rock glacier lacks ice exposures and shows differ-ent internal structures indicating that this is probably an ice-cemented rock glacier.
The Apennines and the Dinarides consist of nappes thrust towards the Adriatic Sea, which is underlain by largely undisturbed rocks. Plate tectonic reconstructions are very varied, with supposed subduction in many different directions. Besides this there is an over-ruling concept that a plate called the Adriatic (or Adria) Plate moved north from Africa to Europe where its collision helped to create the Alps. Some think the plate is still moving. The total tectonic setting, together with palaeontological and seismic data, suggests that the older model of two converging nappe belts meeting a common foreland best fits the observed facts.
Two pedostratigraphic sequences located between the Euganean and Berici hills (Veneto region, north-eastern Italy) were investigated. In such sequences, morphogenic and pedogenic processes could be ascribed to the Late Pleistocene climatic evolution, based on pedostratigraphic characteristics and on archaeological finds. The series prove the degradation of the vegetation cover along the local slopes, followed by the truncation of paleosols due to widespread hillwash phenomena. The latter result in the concentration of coarser elements along an erosional surface, with successive displacement due to gelifluction. This process indicates climatic change towards glacial conditions, with an open environment that is characterized also by loess sedimentation.
The existence of a transatlasic acolian system through the eastern Saharian Atlas point out massive migrations of mobile sands from the High Plains in the North, to the Sahara desert to the South and confirm that in Algeria, there is not a progression of desertification from the Sahara toward the North. The age of these sand displacements is ancient and dates back to the upper Pleistocene and the Holocene. A new chronology of upper Holocene, supported by 12 new datings 14C indicates variations of arid periods and humid periods. This new chronology caracterise an evolution stage since 4000 BP marked by the rapidity of paleoenvironments instabilities during the upper Holocene period through the Zibans range with the development of four sequences: a humid phase during 3300-3000 14C yr BP; an arid phase during 2900-2500 14C yr BP; a humid phase during 2400-2200 14C yr BP; an arid period between 2200 and 1650 14C yr BP dominated by incision of rivers where man's role became more and more higher. The present day remobilisation of sands doesn't justify an aridification of the climate.
This research proposes a new database for the census and characterization of rock glaciers based on the analysis of aerial photographs. The methodology proposed combines the stereoscopic observation of aerial photographs with the use of a GIS for the mapping and identification of the main morphometric parameters of the deposits. Use of the GIS, in fact, allows the measurement of specific parameters (length, width, gradient, etc.). The GIS is also used for the management, organization and visualization of the data, by means of the creation of a database linked with the geographic elements on the map. On the basis of recent research carried out in many alpine areas, the information in the database integrate and update that already available in the literature and used for the Rock Glacier Inventory of the Italian Alps. In particular, the most recent definitions have been used regarding the state of activity of the rock glaciers (classified as active/inactive or relict according to specific characteristics), their geometry (lobe-shaped, tongue-shaped or cqui-dimensional deposits) and general aspect (simple or composite deposits). Other fields of the database define the origin of the debris feeding the deposits, their location, their relation with glacial and nival forms, their relations with local vegetation boundaries and characteristics of their surface morphology. The new database was tested in the Upper Va d'Ultimo (OrdesCevedale Group), an alpine area of about 30 km' with a significant variety of landforms. The application of the database and methodology proposed enabled us to describe adequately an alpine area distinguished by a relevant diversity of landforms, giving us a precise and complete starting point for their monitoring.
Subjectivity is a major problem in the assessment of landscape visual qualities, especially in built up areas. This paper field-tests a quantitative method for visual quality assessment which is based on social survey results, used to define a weighted visual quality scale, which is then calculated and cumulated for each pixel covering land deemed visible from a particular lookout point and converted into map format through a GIS system. This case study of the visual quality in the neighbourhoods of the city of Pécs suggested a north to south decline in the visual quality the the urban landscape. However, different modes of calculation produce widely different results and the approach awaits both refinement and ground-truthing.
The study zone extends over an area of ca. 3.5 km2 in the Tyrrhenian Coastal Chain, northern Calabria, Italy. It includes an east-facing slope for all its length and the valley floor of the Licetto Torrent that drains to the Tyrrhenian sea. The complex Geology is made of different thrust nappes forming an allochtonous tectonic building piled up in Oligocene Lower Miocene, upon which Quaternary alluvial and colluvial deposits lie. Deep-seated gravitational slope deformation of Sackung type affects the Greci slope (Lago, Calabria, Italy). The study faces this complex phenomenon by means of geological, structural, geophysical, geomorphologie, geotechhical, historical and dendrochronological tools. Monitoring of surficial and deep-seated displacements is one of the fundamental investigations. GPS measurements, performed since 1996, depict a complex scenario of displacement, consisting in different sectors moving at rates ranging from less than 0.2 cm/y to 10 cm/y. Measurement of deep-seated displacements have been performed along two inclinometric verticals both 100 m deep. At northern site displacements consist in an upper section 28 m deep moving at a steady rate of ca. 1 cm/y; at the southern site displacement rate is much larger, ca. 10 cm/y, and rather uniform, down to a depth of 60 m. These results provide kinematic data regarding the present evolution of the phenomena, necessary for developing a geotechnical model of the unstable slope and, consequently, to define the most probable collapse scenario.
A geomorphological and geomechanical study was carried out on the calcarenite cliff where the ruins of Canossa casde lie (Reggio Emilia Apennines, Italy). This area is of great historical importance since it was the centre of a very powerful fief in the Middle Ages and has been a national monument for two centuries. In more recent times, it has been subject to degradational problems affecting the rock slopes and posing serious problems for the preservation of the castle and the safety of visitors. The methodological approach utilised is based on a specific survey of rock quality and geomorphological hazard in relation to the high tourist vocation of this geomorphosite.
Land resources management is becoming an important issue in regions affected by natural hazards. The sustainable development of land resources depends on the understanding of the processes and dynamics active within the landscape. In southern African countries soil erosion and the related problems such as water quality issues or decreasing soil productivity are the main problems affecting the inhabitants of rural and urban areas. Therefore increasing attention has been focussed on the problems related to soil erosion over the last few years. This can also be seen from the increasing number of erosion studies and the development and application of erosion models. This study deals with the identification of spatially distributed erosion forms and processes in the Mkomazi-river catchment (KwaZulu/Natal-South Africa) and the Mbuluzi-river catchment (Kingdom of Swaziland). The study was carried out within the framework of an interdisciplinary EU-funded Project aimed at developing an Integrated Water Resources Management System (IWRMS) for water resources analyses and prognostic scenario planning in semi-arid catchments of Southern Africa. Within this more general framework, a concept was drawn up, that integrates the information about the spatial and temporal distribution of soil erosion phenomena. Once the areas subject to different erosion processes and dynamics have been identified, this information can be used in the erosion modelling process, thus providing a fully distributed modelling structure. This structure consists of entities with the same behaviour in terms of their erosion process dynamics and therefore they are called Erosion Response Units (ERUs). Consequently the concept of Erosion Response Units can be utilized to identify the distribution of erosion processes in a river catchment and to model the different erosion processes active within the catchment. The examples from Southern Africa show the methods used to delineate these erosion response units. Furthermore the concept was successfully applied for modelling the soil erosion processes in the catchment.
In southern African countries soil erosion and the related problems like water quality issues or decreasing soil productivity are the main topics affecting the inhabitants of rural and urban areas. Therefore the problems related to soil erosion were more and more focused in the recent past. This can be also documented by a increasing number of erosion studies and the development and application of erosion models. Nevertheless gully erosion phenomena have been completely neglected in erosion modelling. Thus because the development of erosion models was focused on regions with intense agriculture of developed countries on the one hand and because of the spatial and temporal heterogeneity of gully erosion processes on the other. This study regards the identification of gully erosion forms and processes in the Mbuluzi-river catchment (Kingdom of Swaziland) using the Erosion Response Units concept (ERU). The following modelling of the gully erosion was done successively with a physically based dynamic gully model. The input data were obtained by remote sensing techniques (API method) and GIS-analyses. The example from Southern Africa show that the methods applied are able to identify areas affected by gully erosion. Furthermore it is possible to estimate the amount of soil loss due to gully erosion, which is not taken into consideration with the USLE-type models.
Various erosion rate monitors have been exploited to evaluate the denudational history of the Orange River basin from the Mesozoic to the present. Extrapolation back in time from contemporary sediment loads is hazardous, even throughout the Holocene, and low temperature thermochronometry is unable to provide constraints on the recent cooling history, so that a gap cannot be bridged between a Cretaceous period of significant post-rift denudation and a recent acceleration of the human impact. In the first period the role of tectonics may be viewed as the driving force whereas cropland soil losses have dramatically increased through gully erosion during the last century. This paper highlights the limitations of comparing denudations rates over a long period of time as measurements of current processes appear irrelevant for interpreting long-term landscape evolution. Two ways of acquiring an understanding of landforms are to be considered as they bear evidence of an irreducible disparity between the tectonic and anthropic imprints.
In the coast of the eastern promontory of the Gulf of La Spezia (Liguria, Italy), it was identified a scree slope which is partially buried and partially reworked by a following translational landslide. An examination of the morphological and fabric characteristics of the scree slope revealed that it is made up of three stacked layers (a, b, c) of which the lowest (a) corresponds to a talus slope, the middle layer (b) to the accumulation of materials from debris flows and the highest (c) to the combined action of debris flows and localized falls from the overlying walls. The age 14C attributed to a wood sample (Fagus sp.) found inside the scree slope enabled us to associate its formation, and indirectly the formation of the landslide which partially reworks it, to the cold and damp climatic phase that characterised the early Middle Ages (V cent.-VIII cent. A.D.).
Some of the man-made features have integrated into the landscape as its organic part and influence geomorphic and environmental processes. In the paper the function of terraces on arable land (Ackerterrassen) and in vineyards is investigated. The test area is a valley on the western margin of the Odenwald Mountains, the Meerbach valley, near the town Bensheim, Hesse, Germany. In the Rhine valley limited availability of land and the increasing concentration of population called for intensive farming on small plots at a very early date. Although some of the early settlements were later abandoned, some ancient patterns of cultivation manifested in a wealth of man-made features in the landscape, have survived to this day. The landscape ecological significance of terraces is manifested through the redistribution of moisture and nutrients available for agricultural crops. A survey of nutrient losses through runoff was made in various cross-sections and it was found that the partial basins with more terraces insignificantly contribute to the nutrient load of the trunk stream. That is interpreted as an evidence to the efficiency of man-made terraces in the conservation of soil fertility and in the prevention of eutrophication of water bodies.
Thanks to the linear regression method, monthly and yearly temperature gradients have been calculated; in particular the yearly 0.45°C/100 m. Through the altimetric gradient the monthly and yearly altitude of 0°C was calculated. In this last decade, the temperature trend has shown a sensible fall, especially in Spring and in Summer. As far as rainfall is concerned, a negative trend was also revealed for all seasons. In particular, at the Chiotas station the yearly decrease is considerable and may be measured at 23 mm/year. The same trend was noticed in snowfall where, at higher stations, such as the Piastra and Chiotas dams, it reaches 13 and 23 mm/year respectively. -English summary
This paper presents the results of geoarchaeological research in the Portuguese Tagus Valley. Until recently, the Late Quaternary evolution of the Conhal of Arneiro (Nisa, Northeastern Alentejo, Portugal) was poorly examined and understood. Especially the large-scale exploitation for placer gold in historical times complicated the landscape reconstruction, Lis it systematically obliterated large parts of the archaeological and palaeoenvironmental record. The Pleistocene T2 Tagus River terrace was exploited over an area of 0.6 km(2), resulting in the removal of ca. 8.4x10(6) m. Of auriferous sediments. The sterile waste products that were evacuated towards the Tagus and its tributaries, clicked parts of the valleys and covered the Late Glacial-Holocene T1 terrace. A geoarchaeological approach was vital to assess the different natural and anthropogenic processes and their interactions during the Late Quaternary, Firstly, the anthropogenic landforms were identified and interpreted as to their function in the exploitation process. Within this framework, the preserved fluvial landforms could be analysed and the Late Quaternary riverine evolution be reconstructed. It is important to stress the patrimonial value of the Conhal since the unique cultural landscape created by the mining activities has been well preserved. The importance of such old industrial sites is however often disregarded. Of all the placer gold exploitations along the Tagus, only the Conhal area has been declared historical mining patrimony. The research presented in this paper can serve its,I guideline for the analysis of comparable areas and can be a stimulus towards protection and preservation of this unique heritage.
An cxtensional tectonic phase from the Late Pliocene to present with a maximum value in Lower-Middle Pleistocene strongly controlled the evolution of the central Apennines area and the Umbria region as well. Together with this extensional condition, isostatic uplift occurred in Lower Pliocene. As a consequence two large and continuous basins crossed the area from NW to SE. Along the eastern margin of the region, parallel to the first ones, other smaller basins are present. The depressions are recognizable as intramomane basins crossed by superficial drainage networks belonging to River Tevere catchment. Alluvial and colluvial deposits, eroded from neighbouring slopes, fill the basins. Alluvial fans are one of the most common deposition landforms in this environment. In this paper, wc started from a mapping inventory of alluvial fans in Umbria region. Identification and mapping of fans were carried out in the field, by using topographic maps and interpreting two sets of black and white aerial photographs. The boundaries of the fans were also crosschecked using a digital derivate hillshade from the 90 m DEM. The fan boundaries were drawn interactively on the shaded relief map based on the spatial distributions of slope, local relief and curvature. The fans are divided in inactive delta and fan delta and in active alluvial fans. Alluvial fans in technically active areas are related to the ratio of sedimentation to uplift rate. Geometric and sedimentary characteristics of the fans allow to understand the fault activity distribution in lhe region. We supposed a more recent evolution of the fans going from west to cast, according to the extensional stress field migration.
The Nyírség is the second largest alluvial fan in Hungary, built by the Tisza River during the Quaternary. Its typical geomorphic features are dunes belonging to the parabolic dune association, formed at the end of the Würm Glaciation. The Holocene reactivation of dune formation is very unlikely under contemporary climatic setting, though, human activity (deforestation, overgrazing) could lead to sand movement. The aim of the present study is to determine the age and intensity of eolian activity in an interdune depression, in relation with natural and human-induced vegetational changes. For the investigation sedimentological and palynological analyses, radiocarbon and OSL measurements, archaeological findings and archive data were applied. In the Atlantic Phase, despite of humid climate, forest fires were abundant as a consequence of slash-and-burn cultivation. Thus, wind could transport dune material to the studied interdune surface. In the Subboreal Phase agriculture became more and more significant in the area, and runoff and wind erosion intensified. As a result, the wetland was repeatedly covered by thin sand layers. During historical times the radiocarbon and OSL measurements indicate two erosional periods.
The geomorphology of the central Veneto plain has been analysed using a high-resolution DEM, remote sensing and field survey. The study area consists of three alluvial mcgafans: the Montebelluna megafan (Piave River, pre-LGM); the Nervesa megafan (Piave River, LGM - Upper Holocene); the Bassano megafan (Brenta River, LGM). The gravelly, coneshaped, steep (0.8-0.4%) Montebelluna megafan outcrops just in the piedmont sector, as its distal reaches are buried by the Bassano and Nervesa mcgafans. These latter extend from the Southern Alps piedmont to the lagoon of Venice. Within a distance of 10-15 km from the Prealpine foothills, their apical parts are cone-shaped and rather steep (0.60.3%), consisting mainly of gravels. Through a gradual transition, the distal parts become markedly less steep (reaching values ≤ 0.1%) and articulated in systems of fluvial ridges and elongated depressions. The ridges are generally ≤ 1 km wide and several km long. They are mainly composed of sandy deposits, while the depressions are silty-clay. The most significant erosive landforms are related to: i) the head trenching of the Bassano megafan, which probably took place at the end of the LGM because of a disequilibrium between solid and liquid discharges of the Brenta river, related to the de-glaciation of the mountain catchment; ii) the downcutting and lateral erosion of the eastern lobe of the Montebelluna megafan during the Upper Pleistocene and the Holocene, due to the tectonic uplift of the piedmont sector between the Aviano and Sacile faults. Active tectonics at the buried Southern Alpine thrust front led to the faulting of the apical portions of the Montebelluna, Nervesa and Bassano megafans, with the formation of tectonic scarps. Geomorphological evidence of a south-west tectonic tilting of a relict alluvial surface is also detectable in the distal fringes of the Bassano megafan.
The author describes the characteristic features of alluviation related to various types of depressions and tectonic tendencies in the submontane zones presenting the examples mainly from Himalayan foredeep, Carpathian foredeep, Hungarian Plain and Po Basin. He distinguishes active mountain fronts with active aggradation and mature relief of submontane depression dissected by younger valleys. Special attention is concentrated on the role of climatic fluctuations at the PleistoceneHolocene transition and in the Holocene. During last two millennia it is observed a very distinct acceleration of deposition controlled by human activity, which in many cases turned the trend in the alluviation of submontane depressions.
The aim of the research is the 3D reconstruction of a glacier surface through the use of satellite stereoscopic images and Geographical Information Systems (GIS). The project's double goal is to improve Digital Terrain Model (DTM) extraction techniques in morphologically highlycomplex areas and to obtain a high resolution DTM for studying, monitoring, and quantifying the glacial resource. The extraction of the high-resolution glacial surface DTM faces different challenges due to the extreme physical variability of the surface. Glacier ice is a continuously moving deformable material that can locally generate morphologically complex structures such as seracs and crevasses. These features show a seasonal variability linked to meteorological conditions. An additional reason of complexity is the presence of debris (surface moraines) and snow cover: they can apparently alter the spatial shape of the glacier as well as its own elevation. The aim of the research is to identify a fast, reproducible, and reliable method to support the traditional glacier survey and monitoring techniques. From the technological point of view, we also want to verify the chances offered by new remote sensing acquisition systems and relevant elaboration software. This first part of the research has been of value in proving the reliability of the aerial and satellite images plane/elevation data elaboration system, in checking the acquisition difficulties and costs, and in testing the utilization limits of the remote sensed data.
The study of rockfall (volume > 100 m3) in high mountain is essential to understand landscape evolution and to evaluate natural hazards. The number of rockfalls is presently rising in the Alps, while vulnerability is increasing at high elevation and in valleys. Due to the lack of systematic observations, frequency and volume of rockfalls, as well as their triggering factors remain poorly understood. Until today, most of the studies on rockfall carried out in high Alpine rockwalls were indeed devoted to individual events, while systematic surveys are needed to clarify the role of regional factors such as permafrost degradation. Here we present the network of observers (guides, hut keepers, mountaineers) which sets aside the documentation of all the rockfall events that occur in the central part of the Mont-Blanc massif. Operational since 2007, this network allowed identifying and documenting 251 rockfalls between 2007 and 2011. Checked and completed each year by extensive field work, data from the network are then analysed through a Geographic Information System to statistically characterise these rockfalls. The results of the first five years of survey indicate that permafrost degradation is the main rockfall triggering factor.
Eleven stations located at different altitudes in the Italian part of the Lake Maggiore watershed (North-Western Italy) were selected to highlight trends in temperature and precipitation. The data available cover a period of about 30 years for six of the stations and 60-70 years for five sites. Data (maximum and minimum temperatures, precipitation amount, snow cover) were collected on a daily basis, and monthly, annual and seasonal values calculated. The results clearly showed increasing trends of temperature at most sites, with different significance for minimum and maximum temperatures and for the different seasons. Examination of the longest data series suggests that it is mainly in the last 30 years that this tendency towards warming has emerged. No significant trend emerged for precipitation amount, apart from a decrease recorded at one site. The analysis of data on a daily basis at four stations showed that precipitation volume has been quite constant in the last 70 years, while the number of rainy days per year has been decreasing, a particularly striking trend over the last 25-30 years. These results lead to the hypothesis that there has been an increasing occurrence of stormy precipitation events in the last decades.
This study deals with the glacial landforms and deposits of the Vallone Bellunese (Piave glacier) which date back to a period that began with the alpine deglaciation and ended with the Boiling interstadial. This period was characterized by a rapid increase of temperature and a retreat of glaciers from the main alpine valleys. Through the investigations carried out in the last years, in particular detailed geomorphological mapping, drillings, radiometric darings and pollen analysis of two peat-bogs (Modolo and Chiesurazza), it has been possible to reconstruct an upto-date chronological outline of the geomorphological evolution of this area during the Late Pleistocene-Holocene, and to improve the present knowledge on the alpine deglaciation in the southern side of the Alps. The Salce Stadial is defined; in that stadial the equilibrium-line altitude was about 1660 m and therefore it could be considered as one of the «ancient stadials» that occurred just after the LGM. The Salce Stadial had climatic conditions not so different from those of the LGM and an age between 16,200 and 15,000 years BP, therefore it is older than Bölling interstadial.
In the Late Pleistocene, when the Piave glacier retreated from the end moraine system areas towards the Dolomitic region, several large landslides took place in the Belluno Prealps. The chronology of such landslides is mainly based on spatial relationships between mass movements and glacial or fluvial features, but poorly based on radiometric dating. The aim of this study is improving the existing data set on landslide chronology to clarify the relationship between deglaciation and landslides, that is the sensitivity of an alpine environment to climatic changes. The research is based on different types of data (geomorphological field survey, geophysical investigations, drillings, radiometric dating and pollen analysis) and focused on four large gravitational phenomena (Fadalto, Madonna del Pare, Masiere di Vedana and Marziai landslides). Different strategies were adopted in order to date mass movements, according to the environmental conditions in which they occurred. In some cases landslide debris reached a valley bottom free of ice and dammed the valley, whereas in others mass movement took place during deglaciation. Therefore investigations were addressed to define the age of landslide deposits, of lacustrine sediments upstream of accumulation zones and of glacial sediments of specific deglaciation phases, Obtaining chronological information through radiocarbon method turned out a difficult task, mainly for the scarcity of organic matter suitable for dating. Also OSL method did not give satisfactory results. Notwithstanding such dating problems, the use of different data and evidence (geomorphological, stratigraphical, geophysical, and palynological) has allowed a quite accurate definition of landslide chronology. For instance, according to pollen types and concentration it is possible to establish that the landslides occurred during the first phases of deglaciation. The main conclusions are: (a) all the examined mass movements took place between 17,000 and 15,000 years BP; (b) there is a clear relationship between landslides and the climatic changes that occurred during the last glacialinterglacial transition; (c) reaction time of slopes to glacier retreat was relatively short. Finally, we do not exclude the hypothesis that tectonics could have played a role as for slope instability during a period of glacial unloading and lithospheric rebound.
The study presented summarizes selected results of a nationwide glacier inventory project supported by the Swiss National Research Programme (NRP 31) on «Climate Changes and natural Catastrophes» completed in 1999. The data were obtained by the glaciological reconstruction and homogeneous parameterization of the 1850 glacier situation in the Swiss Alps (the last advance period of the Little Ice Age). The statistical comparison with the present-day glaciation (recorded in 1973) provides for the first time a complete synopsis of various glaciological and geographical aspects of longterm glacier retreat in the period since 1850. Attempts were made, based on the new inventory data, to model potential ice decay scenarios for the Swiss Alps and to estimate the glaciological consequences of an enhanced atmospheric warming. Since the end of the Little Ice Age the mean vertical 2:1-ELA shift (AAR = 0.67) of glaciers with normal topographic characteristics is in the order of -90 m. This unfavourable change in mass balance conditions has led to a substantial glacier area loss in the Swiss Alps of approximataly 500 km2 (27 percent) and to an ice volume loss of 33 km (31 percent) The relative amount of ice-decay (area, volume, length) is highly variable on an individual scale but in general shows a significant inverse correlation with former glacier size. The simulation of different 2:1-ELA-rise scenarios outlines the high sensitivity of alpine glaciation in respect of future climate changes. A strongly accelerated but regionally differentiated glacier decay within the next few decades would be the result of the 21st century based atmospheric warming scenarios.
The high mountain landscape is changing, following the climatic trend. Glaciers are retreating and new scenarios and mountain trails are now utilizable by tourists. The environment is somewhere affected by human impact due to the increased frequentation. Where mountain trails are cut on steep slopes a deepening of paths can be observed. In the present work the soil loss along some paths in the Upper Valrellina was estimated. Along paths located below the timberline a dendrochronological analysis was carried out in order to evaluate the damages on roots, and on tree growth. Samples of stems and exposed roots were collected from 34 living trees. Two reference chronologies were built for Larix decidua Mill. and Pinus cembra L. The results show changes in the trees and roots growth in the last rwenty years. The deepening of the trail has been extremely rapid on the lateral moraine of the Forni Glacier (13 mm in less than ten years) on the left side of the valley, frequented since 1995.
In the Alps, there is a long tradition of scientific research on glaciers and on landscapes formed by perennial surface ice. Investigation of problems connected to high-mountain permafrost is much newer. The interest in both, however, has risen considerably during recent years. This is primarily due to their close relationship with climate change. Glaciers and permafrost do indeed react sensitively to changes in atmospheric temperature because of their proximity to the melting point. As a consequence, climatic changes during the 20th century have caused pronounced effects in the glacial and periglacial belts of mountain areas. Fast if not accelerating changes in ice conditions of cold mountain areas now increasingly influence the appearance and perception of alpine landscapes, the seasonality of melt-water runoff, the intensity of erosion and sedimentation, the stability of high-atitude slopes and the general hazard situation. To anticipate and mitigate such consequences of climate change represents a challenge of historical dimensions to the fields of glacial and periglacial geomorphology.
The landscape around the summit of the Monte Beigua Massif (1.287 m a.s.l.) is characterised by the accumulation of large blocks without any source rock faces at their head and by some relict rocky relief. The aims of the present paper are to analyse systematically these landforms, to provide an explanation of their genesis, and to reconstruct the paleoclimatic evolution of this area. Eleven block accumulations have been analysed from a morphological, morphometrical and sedimentological point of view. The block accumulations are all characterised by open work texture at least in the upper 1.5 m, their angular or subangular shape, their frequent vertical dipping, the none or little vegetation in contrast to the woodland coverage just outside the landforms. All these morphological characteristics, and above all, the surface flow structures and pattern blocks, suggest that solifluction, gelifluction or frost creep or a combination of these can be considered responsible for the downvalley movement of these accumulations. To understand whether the periglacial conditions are still present in the area or not, two dataloggers, each one with 4 external thermistors, were installed in January 2003. The subsurface temperature (2 cm) has a range between -13°C and 30°C with very strong diurnal oscillations that, during late winter, can reach 35°C. During the early winter there are very frequent daily freezing-thawing cycles that decrease at the end of the winter and the onset of the spring. The relatively high frost penetration measured now and the usually low winter snow cover suggest a very effective frost action in the past, especially during the Wurm, when the MAAT reached 10-15°C less than in modern times (Clark, 1972) and in this case could be calculated around -2°-0°C. The formation of blockstreams is tentatively attributed to cryotic conditions during the Wurm.
On September 14, 1994, due to rapidly changing meteorological conditions an important debris flow on the northern slope of Mr. Pelmo (Dolomites, Eastern Alps), originating in Val d'Arcia, reached the underlying main road (S.S. 251), covering a part of it. In the detachment zone this event caused the outcropping of a small plate of ice, which extended to about a hundred metres in length, which had remained hidden by the slope debris. Following this event a program of geomorphological, meteorological and geophysical research was carried out in the summers of 1996-99 in the Val d'Arcia. The aim was to ascertain the existence, the extension and the thickness of the mass of ice buried under the detritic cover; to locate the presence of permafrost and to find out the correlations with the debris flow, with respect to the geomorphological and meteorological local context. The geomorphological research was based on a detailed mapping, on a 1:10,000 scale, in the area including the whole Dolomitic group of Mt. Pelmo, with a particular interest to the northern slope, where clear evidence of glacial, periglacial and gravitational processes and deposits still active have been recognised. From the study of this deposits it has been possible to reconstruct the würmian glaciation phases from the Late Glacial to nowadays. In particular, the most recent evolutional history of the glacier has been reconstructed by analysing the terminal moraines of the Little Ice Age present along the eastern sector of the Val d'Arcia. This research has brought to light the areas involved by the debris flow of September 1994, the active landslides on the slopes of Mt. Pelmo and the gullies periodically interested by avalanches. The geomorphological research has been complemented by a detailed meteorological analysis of the September 1994 event, carried out by ARPAV, the Avalanche Centre of Arabba (BL). The geophysical prospection carried out in Val d'Arcia, based on a series of GPR profiles and vertical electrical soundings (VES), pointed out the structures underlying the debris cover. The GPR survey was done using a GSSI SIR-2 device, equipped with 100, 400 and 500 MHz monostatic antennas. Three longitudinal and four perpendicular to the valley axis profiles were made, for a total length of more than 2 200 metres, including the parts of profile repeated with different antennas. The results obtained by the GPR survey along the main 1 km long profile, from West to East for the whole width of the glacier, agree with those obtained by VES which also allowed the calibration of the radargrams time scale. The very high resolution given by this technique allowed the recognition of an interface being interpreted as separation surface between the glacier ant the sub-glacial till or the bedrock and the calculation of the debris cover thickness along the GPR profiles directions.
Top-cited authors
Carlo Baroni
  • Università di Pisa
Francesco Dramis
  • Università Degli Studi Roma Tre
Giuseppe Orombelli
  • Università degli Studi di Milano-Bicocca
Mauro Coltorti
  • Università degli Studi di Siena
Michael Maerker
  • Leibniz Centre for Agricultural Landscape Research (ZALF) & University of Pavia