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Medium-term sediment production and erosion rate in gullies of Fossa Bradanica, Basilicata [Produzione di sedimenti e tassi di erosione a medio termine nei "gullies" della Fossa Bradanica, Basilicata]
No full textGully erosion is an important soil degradation process in a range of environments, causing considerable soil loss and producing large volumes of sediment and it has a very significant contribution to total soil loss in Mediterranean areas. Nothwistanding its importance in the soil erosion processes, gully erosion has been long neglected because it is difficult to study and to predict. Consequently, there is a need for monitoring, experimental and modelling studies of gully erosion as a basis for predicting the effects of environmental change (climatic and land use changes) on gully erosion rates. A key issue to be addressed, as the basis for predicting the effects of global changes such as land use and climate changes, is the mapping and quantification of gully erosion and sediment production rates. At present no standardized procedures are available for measuring gully erosion rates and controlling factors. At the medium-time scale (10-70 years) aerial photographs have been analysed to measure temporal changes in length, area or volume of various gully tipes. In this respect, contribution has been the use of multi-temporal DEMs to map active gully areas and compute sediment production and deposition within gullies. In Basilicata (Southern Italy), agricultural soils underwent continuous degradation during the last century due to the highly erodible nature of outcropping terrains and to the anthropic pressure favoured by the introduction of Common Agricultural Policy (CAP) measures, which, especially in the last 30 years, has led to the reclamation of scrub lands and badlands for durum wheat cultivation. All these practices have accelerated the natural soil erosion processes, leading to the depletion of soil organic matter (i.e. reduction of soil structure stability) and favouring crusting, runoff production, gully erosion and shallow mass movements. On the basis of these considerations, some research questions remain open, the most importance one in Basilicata is: what is the contribution of gully erosion to overall soil loss and sediment production at different temporal and spatial scales and under different climatic and land use conditions? In this paper we attempt to answer to this question adopting the consolidate procedure in GIS to determine medium-term sediment production and deposition rates in a large gullies of Fossa Bradanica, Basilicata, Southern Italy. This method, which is based on the subtraction of multi-date elevation values from digital elevation model, does not produce significant errors in the estimetes and has been considered as a valide technique in the estimating net erosion in gully areas. Infact, in comparison with other methods, it also includes sediment produced by processes other than only overland flow, i.e. downcutting, headcutting, and mass movements and bank erosion
Deep-seated gravitational movements of Craco (Basilicata Ionica) [Il movimento gravitativo di Craco (Basilica Ionica)]
No full textThe Craco ridge (Matera, Southern Italy) experienced repeated landslide movements, particularly along the southwestern slope, starting from the end of the year 1959. The Craco village, located at the top of the ridge, was almost completely abandoned between 1965 and 1980 because of protracted landslide activity. The ridge is oriented NW-SE and is located at the most external thrust front of the
Southern Apennines. A geological and geomorphological survey has been performed in the area that extends between the Salandrella and Bruscata creeks. Detailed mapping has been used to show the relationships between landscape evolution and the various landforms in the frontal part of a recent mountain belt. Furthermore, several exposures document the relationships between strongly deformed tectonic units and the Pliocene deposits, composed of clays, sandstones and conglomerates, that sedimented during the
late deformational stages of the mountain belt (Balduzzi et alii, 1982; Sella et alii, 1988; Pieri et alii, 1997; Bentivenga et alii, 2003). The area underwent generalised uplift since the beginning of Middle Pleistocene, as shown by the altitude of the terraced deposits of the same age, all around the Taranto Gulf (Bentivenga et al., 2004). Interaction between uplift and quaternary climate changes led to the
deposition of terraced alluvial units during the late Middle-Late Pleistocene and to the deepening of the valleys that were filled by minor
aggradational deposits during the Holocene. The detailed geomorphological map is useful to understand the importance of the gravitational
movements in shaping the present landscape. A relationship between the morphological sequences and the deposits responsible
for the landscape evolution has been defined. The slopes of the Craco ridge have been shaped by streams, badland erosional processes, and, more significantly, by huge landslides, that affected all the oucropping lithologies. Multitemporal analysis has been used
to show the evolution of the gravitational movements during the last 50 years. In this paper we suggest that landslides represent the
reactivation of a deep-seated gravitational slope deformation. Furthermore, we propose that evidence coming from studies of
Quaternary geology and geomorphology should be taken into account to analise huge gravitational movements, a relevant topic in risk assessment still poorly investigated in the Italian territory
Geological and geophysical characterization of the Brindisi di Montagna Scalo landslide (Basilicata, Southern Italy)
No full textThe Brindisi di Montagna Scalo Landslide in Southern Italy is an active complex mass movement, which affects the left slope of the Basento River. In the last few decades, this landslide has been continuously monitored, as it directly threatened some of the most important communication routes in the Basilicata Region. Nevertheless, little progresses have been made to prevent further landslide advancement, and continuous maintenance is required. With the aims of better understanding, the main factors controlling the evolution of this landslide, and suggesting the most appropriate countermeasures, a multidisciplinary study, based on the integration of direct and indirect techniques, was carried out. Direct techniques included multi-temporal geomorphological analysis of the slope, alongside geological and structural field observations. Indirect techniques consisted of electrical resistivity tomography acquisition. The combined analyses of the geological and geophysical data showed that Quaternary tectonic processes played a fundamental role as a predisposing factor, whereas seasonal rainfall, and the perpetual undercutting by erosional processes caused by the Basento River at the toe of the landslide are the main triggering mechanisms. The Brindisi di Montagna Scalo Landslide represents an outstanding case-study, concerning the interaction between a flow-like complex landslide and essential linear infrastructure, such as motorways and railways
Note brevi e riassunti del Convegno Annuale del Gruppo Italiano di Geologia Strutturale (Potenza, 7-8 Giugno, 2010)
No full textInfluenza delle precipitazioni e dei cicli umido-secco sulla morfogenesi calanchiva in un’area semiarida della Basilicata (Italia Meridionale)
No full textA new interpretation of terraces in the Taranto Gulf: the role of extensional faulting
No full textThe Taranto Gulf of southern Italy provides an excellent case where it is possible to document the importance of normal faults
in displacing terraced deposits. The study area is located at the front of the southern Apennines, that is a fold-and-thrust belt
developed following the closure of the Mesozoic Tethys Ocean, and the deformation of the Adriatic passive margin during Tertiary
and Quaternary times. The outer, eastern parts of the belt were structured in Quaternary, i.e. up to Middle Pleistocene times.
The front of the chain is partially sealed by Pliocene–Pleistocene foredeep deposits, which represent the infill of the Bradanic
Trough. The upper portion of the middle Pleistocene succession consists of marine sands and conglomerates that in the previous
literature have been arranged in several orders of terraces. Analysis of aerial photographs and geomorphological mapping has
shown the occurrence of prominent geomorphic lineaments, which appear to control the local drainage pattern. Some of these
structures coincide with the map trace of normal faults that produce vertical offsets of the marine terrace surfaces in the order of ca.
10 m each. Many of the fault escarpments reduce their elevation and terminate laterally. In other cases fault escarpments are
laterally continuous and can be traced for up to 3–4 km. Scarp height is between 2 and 10 m. Their mean trend ranges from NNE–
SSW to ENE–WSWand defines an arcuate pattern that mimics the present coastline.
An accurate geomorphological, sedimentological and stratigraphic analysis has been carried out in a selected area of the
Bradanic Trough (Pisticci transect) to investigate in detail the relationships between normal faults and the development of the
terraces. This analysis allowed us to recognise five facies associations related to the upper and lower beachface and to the neritic
clays which represent the substratum of the terraces. More importantly, we observed that all the terraced deposits in the Pisticci
transect could be referred to a single sedimentary body displaced by faults. The terraced deposits are related to an event of beach
progradation, of Middle Pleistocene age, which has been documented in other areas of the Italian peninsula. These results outline
an intimate relationship between the arcuate trend of the recognised fault set and the present coastline pattern. The development of
the normal faults can be related to large-scale gravitational processes developed after the general tilting towards the SE of the Bradanic Trough
Implications of decadal changes in precipitation and land use policy to soil erosion in Basilicata, Italy
No full textGlobal change and long-term gully sediment production dynamics in Basilicata, southern Italy
No full textThe Fossa Bradanica in Basilicata (S Italy) is affected by almost 15% permanent Pleistocene and Holocene gullies. In the past decades climate versus land use management have dramatically increase both the soil loss rate and the muddy-flooding frequency. In this paper the impact of global change on soil production rates and erosion/deposition dynamics at medium-time scale (1949-2000) for two permanent gullies (Fosso Lavandaio and Fosso San Teodoro) has been studied. Pluviometric regime, land use changes and multi-temporal (1949, 1986 and 2000) subtraction method of digital elevation models have been conducted. From 1949 to 1986 the sediment production rate was estimated in 1,988.43 Mg ha -1 year -1 at Fosso Lavandaio and in 808.5 Mg ha -1 year -1 at Fosso San Teodoro, with deposition prevailing over erosion processes. From 1986 to 2000 the sediment production rate was estimated in 2,487.92 Mg ha -1 year -1 at Fosso Lavandaio and in 2,883.9 Mg ha -1 year -1 at Fosso San Teodoro, with higher values of net erosion. The data confirm that the increase in sedimentation would be due to human activities, in particular the levelling of gully heads for the production of cereals and orchards. Differently, the increase of the erosion processes depends on the recent changes of the pluviometric regime characterized by the extension of dry horizon and the concentration of high magnitude precipitation in macro-events of three to four consecutive days. © 2012 Springer-Verlag
Marine terraces and extensional faulting in the Taranto Gulf, Bradanic Trough, Southern Italy
No full textThe front of the Southern Apennines in the Taranto Gulf is sealed by Pliocene-Pleistocene foredeep deposits, which represent the infill of the Bradanic Trough. The upper portion of the Middle Pleistocene succession consists of marine sands and conglomerates, that previous work considered arranged in several orders of terraces. The local drainage pattern appears controlled by priminent geomorphic lineaments. Some of these structures coincide with normal faults with vertical offsets of ca. 10 m each. Their trend defines an arcuate pattern that mimics the present coastline.
Filedwork shows that all the terraced deposits belong to a single sedimentary body displaced by normal faults. The terraced deposits are related to an event of beach progradation, of Middle Pleistocene age, documented in other areas of the Italian peninsula. The recognition of normal faults offsetting a single terrace unit outline an intimate relationship between the arcuate trend of the mapped fault set and the present coaastline pattern. Normal fault development can be related to large-scalòe gravitational processes developed after the general tilting towards SE of the Bradanic Trough
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