ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

a dendrochronological data series as the reference series
represents a particularly reliable starting point because the
delay is calculated in terms of a synthesis of the climatic variables'
as implemented by the trees themselves. Moreover,
this method has the potential for a vast range of applications.
In fact, numerous valley glaciers reached wooded
areas during the advance phase starting from the Little Ice
Age and thereafter. Tree records of the events are thus
available everywhere. Dendrochronological data series may
therefore represent a valid tool for estimating the response
times of Alpine glaciers.
GIOVANNI BATTISTA PELLEGRINI
Some applications of the new Geomorphological Map of
Italy at 1:50,000 Scale. The Sheet (063) BeIIuno
Dipartimento di Geologia, Paleontologia e Geofisica,
Universita di Padova, via Rudena 3,35123 Padova, Italy
This poster aims to illustrate some possible applications of
the Geomorphological Map of the Sheet (063) Belluno, such
as the Geomorphological Asset Map and the Geomorphological
Hazard Map.
The investigated area is in a Prealpine zone characterized
by a great variety of landforms related to its .lithological
and tectonic features. Neotectonic is particularly important
and its effects can be clearly observed expecially in the
drainage network. The main features of this area deal with
morphotectonic, glacial morphology, fluvial morphology
and morphology due to gravity.
Study and mapping of landforms and processes, both active
and inactive, give valuable informations to understand
the evolution of the landscape. These informations help
the decision-maker in the environmental management. Because
of their scales the geomorphological map and the derivative
application maps (geomorphological asset map
and geomorphological hazard map) can not be directly
used for urban plannings or for construction plannings. Inr:
stead, these maps are suitable for an identification of landscape
resources and for regional planning, both for residential
areas and for industrial areas.
The Geomorphological Map allows to define both those
areas that must be protected and valorized because they
are environmental assets, and those areas suitable for human
settlements because there is no geologic or hydraulic
hazard. In environmental planning active slope processes
limit the use of certain areas. This means to consider not
only the landslides, active or dormant, known and mapped,
but also slopes that can be subjected to possible future
failures. Other areas not suitable for settlements are those
that can be flooded or that can be involved by fluvial
erosion.
In the Belluno area other edification limits exist because
the whole area is classified as a sismic zone (Znd category).
The Geomorphological Asset Map points out those features
of the landscape that have a special value from a cultural
and a naturalistic point of view and that should be protected
and valorized.
The Geomorphological Hazard Map shows those areas
where there are active geomorphic processes or that are
potentially unstable, as it results from the Geomorphological
Map.
FERNANDO X. PEREYRA
Break up of Gondwanaland and long-term landscape
evolution of Pampean Plains, Argentina
Department of Geological Sciences, Fce y N-Uba, C. Universitaria,
Pab. II, 1428 Capital Federal, Argentina
Until present there are not studies that relate the geomorphic
evolution of Pampean Plains with its tectonic setting.
The Pampean Plain has more than 600000 km', placed
beetween 30 -38 Sand 57 -65 W, in central eastern
Argentina. It consist basically in a gently rolling landscape
resulting from fluvial (large floodplains) and aeolian (loessic)
accretion. The region tectonic setting corresponds to a
passive margin (lower plate), composed of positive and negative
elements. These are related to differential behavior
due to the breaking up of Gondwanaland (Atlantic Ocean
formation), mainly by reactivation of precambric and paleozoic
ages structures. The positive elements are Sierras
Australes, wich is a late Paleozoic-Triassic collision orogen,
and Sierras Septentrionales, an older system of precambrian-early
paleozoic ages. Northeast of the region, in subsoil
and outcropping in Uruguay, is the Rio de la Plata
Craton, also Precambric. Negative elements are: Salado
Basin, an aulacogene (+ 6000 m of subsidence) and Colorado,
Macachin, Rosario and Laboulaye intracratonic basins,
all of these related to the opening of Atlantic Ocean,
developed beetween late Jurassic and middle Tertiary
mainly by tectonic subsidence. The development of these
basins was partially responsible for the uplifting of neighbouring
areas, possibly by upwarping: flexural isostasy because
of denudation and subsidence of the basins by deposition
added to the effect of domal uplift related to drifting
and non uniform extension. These structures experimented
some reactivation in upper Cenozoic by Andean Orogeny
and the development of the passive margin.
The existence of two remnants of planation surfaces (coinciding
with the ranges of Buenos Aires Province), partly
eroded and fragmented by late mesozoic-tertiary uplifts is
proposed. They resulted from the presence of a cratonic
regime, formed by etchplanation, pediplanation and fluvial
processes, probably during the Triassic-middle Jurassic lapse.
Paleogeographic data show evidence of periods of
subtropical climates for this region of Gondwanaland
before the opening of the Atlantic Ocean. Planation surface
of Australes Range was developed in early-middle Pa-
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