The glacial traces in the «parco Nazionale d 'A bruzzo » area (Central Apennines): Preliminary note

In the mountainous area of the «Parco Nazionale d' Abruzzo »,
characterized by several massifs with maximum altitudes frequently
above the 2 000 m, a large number of glacial traces can be observed.
The examination of new evidence discovered and the re -examination
of those already known has permitted to reconstruct several distinct
glacial events. In the studied area the cirques are the most frequent
forms due to glacial modelling, even though other glacial remains like
troughs and moraine deposits are found in association with them. In
a number of places the existence of several episods of glaciation is
provided by the occurence of a cirque stairway observed on the same
slope. Starting from the more complete and best preserved local sequence an attempt was made to put into order all the other glacial traces.
Correlations have been based on relative position and morphology of
the cirques and the snow limits. As a result, it seemed likely to refer
the observed evidence to four distinct events of glaciation. The first
glacial event (pre -wiirmian glaciation, probably Riss) is characterized
by a snow limit situated about 1 340 meters a.s.l, and evidenced by
few glacial forms in the massifs of Toppe del Tesoro, S. Nicola and
the Meta Mountains. They consist of large badly preserved cirque-like
depressions situated about 1 300-1 400 meters a.s.l., and moraine
deposits whose position and distribution largely contrasts with the actual orographic configuration.
During a new glacial advance (maximum wiirrnian expansion) the
snow limit rised to 1 560 m. Numerous are the traces relative to this
ad vance, consisting in a large number of erosional forms , like cirques
and glacial troughs, and morainic deposits which frequently preserve
their ori ginal morphology forming lateral and frontal moraines.
The third event (first late Wiirmian stage = first apenninic stage
of FEDERICI, 1979) is characterized by a further rise of the snow limit
now situated about 1 760 m. The evidences rel ative to this minor expansion consist only of erosional forms except one morainic deposit
rico gnized on the eastern side of the Meta Mountains. Effects relative to the fourth event (second late Wiirmian stage = second apenninic sta ge of FEDERICI, 1979) can be observed only in the reliefs situated North of the Sangro Valley and in the Meta Mountains, while
in the other reliefs the snow limit, situated about 1 970 m, had already
reached or passed the altitude of their highest peaks.
A summary examination of the distribution and the morphological
features of the glacial traces studied shows that the area South of the
Sangro valley seems to have developed greater glaciers that the part
of the studied area situated at the North of the same valley.