ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

of 5-20 m in the zone of wave transformation, and it is divided
into substows of ancient bar (with a height of 3.5 m,
and a length of 200 m), bedplate - an ancient bed of inflowing
river, flattened, slightly inclined, terrace side and
fragments of abrasion ridges. The facies of substows of ancient
accumulative terrace are also divided on the basis of
biogeocenotic varieties.
Complete sets of Bnc are encountered only in bays; and
they are composed of three, for benches, and of two, for
accumulative plains, terraces of different height and age.
The called units of a morphological division are either partially
absent or are undefined in a topography in other coastal
forms. A depths, where a bench is overlain with a mantle
of accumulative sediments, is different for each of compound
stows depending on a coastal topography, proximity
of a river delta and a volume of a river flow, and a type
of water body and a direction of along-coast constituent
of drift-gradient currents. It is established that the individual
set of BNC of lower rank is typical of each of 15 compound
stows modificated with the help of a correlation
analysis.
MAY C. MODENESI-GAUTTIERI\ SILVIO T. HIRUMA 1
& CLAUDIO RrCCOMINI 2
Geomorphological evolution and tectonic reactivation in
a tropical plateau (Campos do ]ordao, SE Brasil)
1 Instituto Geologico, Secretaria do Meio Ambiente do Estado de Sao
Paulo, Caixa Postal 8772, 04301-903, Sao Paulo, SP, Brasil
2Instituto de Geociencias, Universidade de Sao Paulo and Research Fellow
of Cnpq, Caixa Postal 11.348, 05422-970, Sao Paulo, SP, Brasil
The distribution and nature of landforms in southeastern
Brasil clearly show the heritage of the Cenozoic tectonic
processes that followed the opening of the south Atlantic
ocean basin. During the Palaeogene (Eocene-Miocene)
normal reactivation of old Brasiliano/Pan-African shear
zones brought about a striking tectonic feature: the Continental
Rift of Southeastern Brasil. In eastern Sao Paulo this
structure is topographically expressed by the Serra do Mar
and Serra cia Mantiqueira, as elevated geomorphic units,
and the Taubate Basin, as the downthrown unit. Further
uplift of probable Miocene/Pre-Pleistocene age would have
accentuated differences in altitude between compartments.
At the southwestern end of the main block of the Serra da
Mantiqueira, the Campos do jordao Plateau is individualized
by morphostructural and climatic characteristics. During
the Quaternary its elevation above 2000 m resulted in
a typical tropical montane landscape system, the «altos
campos». On the summits of the plateau (1900-2007 m),
this landscape is characterized by local relief of 40-50 m,
generalized hillslope convexities, shallow slope depressions
and relatively broad floodplains filled with peaty sedi-
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ments. In this area, along the northeast-trending lineaments
of the Precambrian Jundiuvira Fault, the Galvao
valley presents three geomorphological compartments separated
by breaks in the longitudinal profile. Knickpoints
occur where the Jundiuvira fault cuts lineaments in zones
with evidence of reactivation that seem to have been preferential
sites for the stream piracy phenomena observed
along the Mantiqueira divide. These facts plus morphological
evidence such as assymetric valleys with straight scarps,
triangular and trapezoidal facets, hanging valleys, countercurrent
confluence, etc., are indicative of the reactivation
of ancient regional structures.
Morphostructural analysis of part of the Campos do
Jordao Plateau, including characterization of Quaternary
deposits and brittle tectonic structures, has led to the identification
of three superposed neotectonic regimes of Holocene
age: an initial E-W right-lateral transcurrent binary
with left-lateral movement of NNW transcurrent faults,
followed by E-W extension that affected stone-line deposits,
and a final E-W compression that generated shear
joints in colluvium, organic-rich soils and peat deposits.
Quaternary evolution of the landscape of the main tropical
montane system of southeast Brasil thus reflects a combination
of climatic influences and recurrent neotectonic
activity.
SALVATORE MONTELEONE, GIUSEPPE PIPITONE
& MARIA SABATINO
Geological and environmental characteristics of the new
towns built after the 1968 earthquake in the Belice Valley
(Western Sicily)
Dipartimento di Geologia e Geodesia, Universita di Palermo,
corso Tukory 131, 90134 Palermo, Italy
In January 1968 an earthquake of magnitude Richter 6.0
shook western Sicily causing over 400 deaths. The epicentre
was in the valley of the River Belice. The earthquake
caused considerable damage in ten
towns in the provinces of Agrigento, Palermo, Trapani and
totally destroyed the towns of Gibellina, Poggioreale and
Salaparuta in the province of Trapani, and Montevago in
the province of Agrigento. These towns were rebuilt in
new locations some kilometres from the original sites. The
choices regarding the new sites and their urbanization were
in the responsibility of the State.
This study on the new sites of Gibellina, Poggioreale and
Salaparuta shows that missknowledge of the geological,
geomorphological and geoenvironmental characteristics
led to mistaken choices of territorial planning when reconstruction
began. It has been found that the modifications
to morphoevolutionary processes caused by human intervention
have triggered considerable alterations in the evolution
of the territory, creating a situation of hydrogeologi-