ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

FULVIO BARALDI 1, DORIANO CASTALDINI 2
& MAURO MARCHETTI 2
Geomorphological impact assessment in the
River Mincio Plain (Province of Mantua, Northern Italy)
1 U.O. 4.8 Gruppo Nazionale Difesa dalle Catastrofi Idrogeologiche,
Cnr, 41100 Modena, Italy
2 Dipartimento di Scienze della Terra, Universita di Modena,
l.go S. Eufemia 19,41100 Modena, Italy
The research takes into account the landscape modifications
induced by man's activity in the past 40 years in the sector
of the River Mincio plain located between the Pleistocene
morainic hills of Lake Garda to the north and the Mantua
lakes to the south. From the geomorphological standpoint
the study area is comprised within a stretch of territorymade
up of the outwash plain deposited by. the spills of the
Garda glacier and the wide triangle-shaped depression cut
by the river Mincio, north of the city of Mantua.
The morphological setting within this depression is characterised
by several scarps of varying height, mainly developed
in a N-S direction, which form various orders of terraces.
The study includes a detailed bibliographical research,
the examination of maps and of aerial photographs taken
in different years and a morphological survey carried out
in the present day.
The plain sector considered has been subjected to intense
quarrying activities since the beginning of this century, because
the outcropping sediments have good characteristics
as building materials. Indeed, the outwash plain and the
terraces inside the Mincio erosional depression are mainly
made up of rounded coarse gravels. From a petrographic
viewpoint, carbonatic, magmatic and metamorphic rocks
are present in various percentages.
The open quarries are classified as trench quarries exploited
above the water table and trench quarries exploited
below the water table. The first-type quarries are excavated
only up to a depth of a few metres below the original
ground surface and, in any case, up to about 1 m above the
maximum level of the water table. When no longer in use,
these quarries are reclaimed for farming after the laying of
a pedogenised level of organic soil on their floor. The second-type
quarries can reach a depth of up to 20 m and
when no longer in use are abandoned or in some cases
used as occasional dumping sites or equipped for recreational
fishing.
All these quarrying activities have caused relevant landscape
changes. The trench quarries above the water table appear
as large, deep rectangular holes, which impress an
«artificial» look on the area affected; also the trench quarries
below the water table have formed several small ponds
which are extremely different in shape from natural bodies
of water (moreover, the interception at ground level of the
most superficial aquifer causes potential pollution hazards
owing to the possible uncontrolled inflow of waste materials).
More in general, quarrying activities have implied
the partial or total obliteration of relict fluvial landforms,
such as terraces and paleo-riverbeds.
The reclamation of the quarrying areas implies their restitution
to farming practices, according to management criteria
based on the safeguard of natural assets and landscape
values.
Another aspect of man'S activities during the past decades
concerns the construction of important artificial canals
(Scaricatore Pozzolo-Mincio and Diversivo Mincio) which,
besides modifying the natural flow of both surface and
sub-surface waters, have altered the natural morphological
features of the areas affected.
In this research a simple methodology for the assessment
of the scientific quality of landforms was applied. According
to this model, the scientific quality for each element
of the landforms is given by the product of their intrinsic
scientific value and their condition of preservation. The
impact on the landscape is defined as the reduction in
scientific quality due to the assessment of the degree of damage
produced by man's activity in the past 40 years.
ILONA BARANY-KEVEI
Connection between morphology and ecological factors
of karstdolines (Aggtelek Hills, Hungary)
Department of Physical Geography, University of Szeged,
H-6722. Szeged, p.o. box 653, Hungary
The Aggtelek Karst Region was declared as a part of
World Heritage on 2 December 1995. Its surface and subsurface
karst formations are worth protecting. Since the
formation of the Aggtelek National Park (1985) the measures
taken to limit human activity have brought about some
predictable improvement in maintaining a state close to
the natural conditions.
The karstdepressions in Aggtelek are situated in various
orographic, lihologic and tectonic situation. On this basis
three main groups may be distinguished (Barany & Mezosi,
1995): dolines situated at the height 310-350 m, 270-280
and around 500 m. Present paper permitted to identify first
of all the connection between the doline assymetry and
ecological processes. Karstdolines are environmentally very
sensitive site point of the karst region, for this reason the
research of environmental change in this form is very important,
too. Morphology of dolines indicate the characters
of doline-development depend on exogenic factors.
The climate and the microclimate play the most important
role of doline development. The soils covering the karstforming
rock, through the a-biogeneous and biogeneous
processes going on in them, indicate the nature and the order
of magnitude of the corrosion process.
From this point view by the side of climate and microclimate
the vegetation play an important role in the intensity
of corrosion. In Aggtelek we have found lot of degraded
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