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RIBOLINI A., ISOLA I., ZANCHETTA G., BINI M. & SULPIZIO R.

Glacial features on the Galicica Mountains, Macedonia: preliminary
report

Pages 247-255

Abstract

Glacial features were described for the first time on the Galicia Mountains, a mountain range separating the lakes of Ohrid and Prespa in Macedonia. The geomorphological mapping of part of this range allowed to document the existence of frontal and lateral moraines, as well as trimlines, cirques and polished rocks. These glacial features allowed the reconstruction of the original topography of the glaciers that deposited the frontal moraines. The Equilibrium Line Altitude (ELA) of three different phases of expansion was calculated (ca. 1850 m, ca. 2000 m and 2130 m a.s.l.) through the Area-Altitude Balance Ratio (AABR) method, and correlated with the values available for the Balkan region and northern Greece. An attribution to Last Glacial Maximum (LGM) and Lateglacial (Oldest and Younger Dryas) was argued for the glacial phases of Galicica Mountains, in agreement with the ELAs of dated moraines in the region, as well as in the Apennines and Maritime Alps. Through the extrapolation of summer temperatures at the ELAs for the single glacial phases, the amount of precipitation needed to sustain the glaciers existence was calculated (3500-3700 mm of weq) using a well established polynomial regression. The attribution to the LGM of the lowermost frontal moraine points out to an older age for the till found well below the examined area, near the Prespa Lake shore. This indicates that a more extended glaciation phase occurred during the Middle Pleistocene.

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RASKA P., KIRCHNER K. & RASKA M.

Winter microclimatic regime of low-altitude scree slopes and its relation to topography: case study from the Ceske Stredohori Mts. (N Czech Republic)

Pages 235-246

Abstract

Many low- to mid-altitude Central-European scree slopes display microclimatic regimes with thermal anomalies throughout the year. These anomalies favour stenoecious species, some of them considered to be glacial relics. In this study, we present a pilot study focusing on the evaluation of topographical factors (elementary landforms, slope profile, clast size) that predispose the formation of different microclimatic regimes at screes that have similar physico-geographical characteristics. We carried out detailed geomorphologic mapping at four scree slopes in the Ceske Stredohori Mts. (Northern Czech Republic). The mapping was supplemented with snow cover monitoring, observations of microclimate-induced features (ice holes with cold air exhalation and vents of warm air), and temperature measurements from the prolonged winter period of 2007-2008. The results showed distinct differences in the microclimatic regime of the four study sites. A concave foot slope built by large boulders was the major factor inducing cold exhalations and the persistence of ice and snow. Slope inclination and vegetation patterns played a limited role. Warm vents within the upper part of the screes were strictly related to specific landforms (terminal lobes and elevations) and to mid-size clasts. The results are discussed using a geomorphologic evaluation of sites in the region that display thermal anomalies. The regional analyses indicate that the warm vents are mainly located on the southern slopes (due to higher incoming solar radiation) and at higher altitudes. The screes with cold air exhalations (freezing screes) are located at lower altitudes and on slopes with different orientations.

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MICCADEI E., MASCIOLI F., ORRÙ P., PIACENTINI T. & PULIGA G.

Late Quaternary paleolandscape of submerged inner continental shelf areas of Tremiti Islands archipelago (northern Puglia)

Pages 223-234

Abstract

The Tremiti Islands archipelago, located north of Gargano promontory’s coast, is part of a complex geological area within the Adriatic basin, facing the junction between central and southern Apennines. This area is well known for Neogenic-Quaternary stratigraphic, tectonic and seismologic aspects and is crucial for the definition of Late Quaternary Adriatic basin evolution. This work gives a contribution of geomorphological data concerning the inner continental shelf around the islands. It incorporates bathymetrical analysis and side scan sonar survey, focused on the recognition of main submerged landforms, from coastline down to about 70 m b.s.l. Geophysical acquisitions were improved with direct observations, carried out by means of a two year scuba-dive geomorphological survey. The study of continental shelf outlines a geomorphologic setting that includes marine and coastal features, but also tectonic, fluvial, karst and slope landforms. The correlation of the below sea level geomorphological features, with landforms and deposits of above sea level areas, provide a contribution to the reconstruction of Late Quaternary landscape and geomorphological evolution, as the result of tectonics, sea-level fluctuations and marine, coastal, and continental geomorphological processes.

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MASTRONUZZI G., CAPUTO R., DI BUCCI D., FRACASSI U., IURILLI V., MILELLA M., PIGNATELLI C., SANSÒ P. & SELLERI G.

Middle-Late Pleistocene evolution of the Adriatic coastline of Southern Apulia (Italy) in response to relative sea-level changes

Pages 195-206

Abstract

The Adriatic coastal area stretching from Monopoli to Brindisi in Apulia is characterised by landforms and marine/coastal deposits of Middle- Upper Pleistocene age. An E-W striking fault system, roughly corresponding to the geographic “Soglia Messapica”, is also present. This area shows the effects of different phases of coastal evolution. During the Middle Pleistocene, north of the Soglia Messapica, thin coastal deposits accumulated and abrasion surfaces were cut whereas, to the south, marine sediments were deposited. During the last interglacial period, two thin transgressive beach deposits formed along with a dune belt and backdune deposits. From the geodynamic point of view, facies and elevation of marine and coastal deposits suggest that before 125 ka the region north of the Soglia Messapica was uplifting with a higher rate than the southern one. Afterwards, both areas north and south of the Soglia Messapica showed a similar tectonic behaviour, characterised by stability or, locally, by low subsidence rates. Mesostructural analysis on extensional joints indicates that at least three separate deformational events occurred during the Middle and Late Pleistocene. If matched against the uplift rate changes, this structural evolution may be interpreted as due to the shift toward the SE of the peripheral bulge related to the Ionian slab subduction process and to the set up of a different tectonic event in the Late Pleistocene. In the study area such event is essentially characterised by widespread stability, coupled with the development of joint sets which suggest a doming- like deformation mechanism.

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LEONELLI G., BATTIPAGLIA G., CHERUBINI P., MORRA DI CELLA U. & PELFINI M.

Chemical elements and heavy metals in European larch tree rings from remote and polluted sites in the European Alps

Pages 195-206

Abstract

Air pollution dispersal in the European Alps has been studied both
for glacial and forest environments. In this study, chemical elements and
heavy metals in the tree rings were analyzed for seven sites of European
larch (Larix decidua Mill.) in the Italian European Alps. At three sites in
the proximities of the Mont Blanc Tunnel (MBT) entrance the analyses
were performed at the yearly scale on the periods 1950-1970 (comprising
the MBT opening in 1965) and 1985-2008 (comprising the 3-yr MBT closure
after the 1999 car accident) with the aim to check if trees recorded at the yearly scale variations in chemical elements and changes in heavy metals concentrations over time. At the regional scale, the analyses on heavy metals were conducted without annual resolution for most sites on the common periods 1950-1970 / 1985-1998 with the aim to detect possible ongoing trends and differences between some Alpine sites. Chemical elements concentrations at Entrèves (EN) sites varied significantly between heartwood and sapwood with generally higher concentrations in sapwood. At EN sites no clear patterns were found for heavy metals before and after the MBT opening and during its 3-yr closure. We found that the “high” site (ENH) was generally less polluted than the “close” (ENC) and the “far” (ENF) sites. At site ENC we found higher values of Cr, Ni and Cu, whereas at site ENF we found higher values for all the other elements analyzed. The analysis of heavy metals at the regional scale revealed generally no significant temporal changes in concentrations except for Cr and Cu, showing higher values in the recent period. On comparing the heavy metals concentration between the seven sites, the Palud site showed almost always the highest concentrations, except for Ni and Cu that were higher in two remote sites close to glacial environments in the Gressoney and Valtellina valleys. Dendrochemical analysis revealed that the temporal information in the tree rings is covered by too many signals and no environmental changes are recorded at the yearly scale by European larch. However tree rings may provide useful information on ongoing long-term trends and on the spatial definition of pollutant dispersal in the Alpine environment.

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LENTINI G., CRISTOFANELLI P., DUCHI R., MARINONI A., VERZA G., VUILLERMOZ E., TOFFOLON R. & BONASONI P.

Mount Rwenzori (4750 m a.s.l., Uganda): meteorological characterization and Air-Mass transport analysis

Pages 183-193

Abstract

The meteorological conditions at Mount Rwenzori (RWZ), in Western Uganda, are explored by analysing meteorological observations carried out during the years 2006-2009 by an Automatic Weather Station (AWS) installed at 4750 m a.s.l. in the eastern part of the Mount Stanley (0° 22’ N and 29° 52’ E), the most extensive RWZ glacial mass.
The AWS provides hourly measurements of the main meteorological variables: air temperature, rain precipitation, atmospheric pressure, relative humidity, wind speed and direction, and global short-wave irradiance. In this work we described the typical seasonal and diurnal variations of the meteorological parameters recorded during the period October 2006 – August 2007 and July 2008 – June 2009. Throughout these periods, a remarkable low variability of the main meteorological parameters is detected, as expected for an equatorial high-altitude site. Only for the rain precipitation amount a direct influence of the Inter Tropical Convergence Zone (ITCZ) can be detected. As deduced by the analysis of the typical seasonal diurnal variations, the local mountain weather regime is likely to dominate the variability of the meteorological parameters at RWZ. These measurements permitted to characterize for the first time the meteorological conditions of the Rwenzori Mountains. In addition, the Lagrangian model HYSPLIT has been used to calculate a 2-year climatology of three-dimensional air-mass back-trajectories in order to provide a description of the synoptic-scale atmospheric circulation affecting the measurement site, and verify the seasonal influence of the ITCZ on large-scale atmospheric circulation at RWZ.

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DUNCAN R., GINESU S., SECCHI F. & SIAS S.

The recent evolution of the Sinis region (western coast of Sardinia, Italy) on the basis of new radiometric data of the pliocenic volcanism

Pages 175-181

Abstract

The present paper focuses on the relationships between Pliocene volcanic activity and geomorphological evolution of Sinis region (western Sardinia, Italy). Plio-Pleistocene volcanic activity plays a key role in the recent landscape evolution. Morphological evolution has been reconstructed on the basis of chronological data obtained on different volcanic episodes.
In order to constrain the evolution model, Ar/Ar radiometric studies have been carried out on volcanic episodes of Sa Mulargia and Catalano island. The landscape is characterized by smooth morphologies and a poorly defined hydrographic network; volcanic relief shows relief inversion processes. These processes produced a roughly NS trending drainage in the western sector, favored by extensional faults that conditioned the geomorphological features commonly observed in the coastline. Several ponds in the eastern Sinis area are likely related to the interaction of morphogenetic processes favored by tectonic activity and sea level fluctuation and variation of Tirso river, the main river of Sardinia.

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AUCELLI P.P.C., FORTINI P., ROSSKOPF C.M., SCORPIO V. & VISCOSI V.

Recent channel adjustments and riparian vegetation response: some examples from Molise (Italy)

Pages 161-173

Abstract

An integrated geomorphological and ecological approach was adopted to investigate the relation between recent channel adjustments and riparian vegetation evolution by performing a large-scale multi-temporal analysis of channel and land cover features and a study of the present-day floristic setting along the three major river systems present in Molise (Southern Italy), the Volturno, Biferno and Trigno. Our results highlight
the major channel adjustments that occurred between 1954 and 2009 consisting in progressive morphological changes, extreme channel narrowing (between 84% and 97%) and moderate to very intense channel incision (between 2 and 10.5 m). These channel adjustments led to the progressive stabilization of most of the formerly active channel systems and were accompanied by substantial changes in the riparian vegetation
which now appears largely, but not completely, in equilibrium with the present river dynamics. Major differences may be noted between the studied river reaches in relation to their state of naturalness, floristic richness and differentiation in vegetation types, which appear particularly controlled by the amount of channel incision and human disturbance. Our findings underline the importance of fluvial dynamics and trends in controlling the development and structure of riparian vegetation and the connected ecological status of river systems.

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SURIAN N., RINALDI M. & PELLEGRINI L.

Channel adjustements and implications for river management and restoration

Pages 145-152

Abstract

Most Italian rivers have experienced widespread channel adjustments over the last 100 years, mainly in response to a range of human activities. The aim of this paper is to show how knowledge of channel adjustment and reconstruction of evolutionary trajectory are or can be used in river management and restoration. The first part of the paper deals with channel adjustments and summarizes the results of recent studies carried out on twelve rivers in northern and central Italy. The second part illustrates three examples of application. The selected rivers have undergone almost the same processes in
terms of temporal trends. Initially, river channels underwent a long phase of narrowing (up to 80%) and incision (up to 8-10 m), which started at the end of the 19th century and was very intense from the 1950s to the 1980s. Then, over the last 15-20 years, channel widening and sedimentation, or bed-level stabilization, have become the dominant processes in most of the rivers, though channel narrowing is still ongoing in some reaches. Channel adjustments were mainly driven by human actions, but the role of large floods was also notable in some cases. Different human interventions have been identified as the causes of channel adjustments (sediment mining, channelization, dams, reforestation and torrent control
works). Such interventions have caused a dramatic alteration of the sediment regime, whereas effects on channel-forming discharges have seldom been observed.

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