ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

VALERIO AGNESI 1, MAURIZIO DEL MONTE 2, CIPRIANO DI
MAGGIO \ PAOLA FREDI 2 , TOMMASO MACALUSO ', SILVANA
MARINO 1 & VINCENZA MESSANA 1
Integrated geomorphological analysis of a drainage basin
of Sicily (Italy) as basis for the correct territorial
management
1Dipartimento di Geologia e Geodesia, Universita di Palermo,
Palermo, Italy
2 Dipartimento di Scienze della Terra, Universita La Sapienza,
Roma, Italy
In Sicily, like in other mediterranean regions, the shaping
of the relief is mainly determined by slope processes. These
processes are principally surface water erosion phenomena
and mass movements, and are particularly active at
the time of very intense rainfall, with disastrous effects, following
which the interventions usually involve great expense
for the public but often have unsatisfactory results.
The correct management of a territory thus requires proper
geomorphological studies, which are indispensable
for the identification of relief shaping processes and the
definition of their role in the evolution of the physical environment.
The case considered consists in the geomorphological
study of the basin of the Fiume Imera Settentrionale (Western
Sicily). The study was conducted in integrate manner.
On one hand geomorphological survey and the compilation
of thematic maps on various scales were carried out,
with the aim at identifying active geomorphological processes;
on the other hand quantitative analysis technique were
used in order to assess the entity of these processes.
The examined basin flows to the Tyrrhenian shore and extends
for 342 km'; it is characterized by the presence of extensive
outcroops of claystones in the middle-low sectors
of the slopes and in the valley floor areas, while the upper
parts of the slopes consist of successions of calcareous
rocks. The whole basin presents considerable problems
with regard to processes of geomorphological evolution,
mainly evidenced in widespread landslide phenomena of
marked cyclic character and in highly active linear and
areal erosion processes affecting extensive portions of the
slopes and determining diffuse geomorphologically hazardous
conditions. This state has strongly influenced human
activities and given rise to an agricoltural and pastural subsistence
economy; while the building in the basin of a stretch
of the Palermo-Catania motorway (of fundamental importance
for Sicily) led to considerable impact on the environment
and to drastic modifications of the river bed, which
has enhanced the geomorphological risk.
This study is divided into various phases regarding geomorphological
cartography on various scales and detailed
field analyses of important landslide phenomena. An assessment
was made of the extent of areal erosion processes by
means of surveys and detailed enquiries in significant areas
and through quantitative analysis of the main morphometric
features of the watershed.
The findings of the research, in association with quantitative
results based on measuring of solid load effected in the
last few years, have made it possible to correlate theoretical
data with directly measured ones. The study has allowed to
assess the role of landslide and erosion phenomena in the
slope processes of sample areas characterized by different
geological and geomorphological conditions. It has also
been possible to define the variability of the intensity of
these processes in climatically homogeneous zones and to
quantify the entity of erosion by the compilation of erosion
index maps for homogeneous areas, thus providing the
premisses for the correct management of the territory.
VALERIO AGNESI, CIPRIANO DI MAGGIO
& TOMMASO MACALUSO
Morphostructural setting and geomorphological evolution
in the Madonie Mountains (Northern Sicily, Italy)
Dipartimento di Geologia e Geodesia, Universita di Palermo,
corso Tukory 131,90134 Palermo, Italy
Geomorphological studies conducted in the Madonie
Mountains have made it possible to identify various
morphostructures responsible for the differentiation of the
landscapes in this sector of the Sicilian Apennines. The
tectonic style of overthrust nappes and faulted fold, which
distinguishes this sector, and the lithological features of
outcropping rocks have determined the occurrence of relief
forms strongly controlled by structural setting. On the
basis of the different geomorphological configuration it is
possible to distinguish four broad sectors:
1. the Monte dei Cervi massif, consisting of rocks with different
geomechanical behaviour affected by a faulted anticline;
these conditions have favoured the development of
forms of selective erosion and the activation of deep seated .
gravitational slope deformations, which have given rise respectively
to structural slopes, large morphoselection depressions,
trenches and areas with isolated and variously
rotated blocks;
2. the Pizzo Carbonara and Pizzo Dipilo reliefs, consisting
of intensely faulted and fractured calcareous rocks which
have determined the presence of small and large karst
forms aligned along the main tectonic directions;
3. the Monte Quacella-Monte Daino massif, consisting of
intensely fractured dolomitic rocks, the escarpments of
which are considerably degraded by mechanical disgregation
and gravitational phenomena and are delimited by
thick debris nappes;
4. piedmont areas, characterized by marly-clay and arenaceous
outcrops, with cuesta type monoclinal structures
that are widely affected by mass movements and surface
water erosion phenomena.
The highest portions of many of the reliefs consist mainly
of calcareous rocks, and present remnants of suspended
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