ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

depositional body. The faster the sea-level fall, the more
probable the preservation of depositional bodies above the
retreating sea, e.g. in the form of beach ridges and coastal
dunes. An analysis supports similar results obtained on the
coasts of the Caspian Sea, an interior water body with the
extreme annual water-level fluctuations.
As a first approximation, a model of coastal development
under accelerating sea-level rise is established for the conditions
of excessive and insufficient sediment supply on
sand coasts. Under the former a moderate acceleration of
sea-level rise causes the change from mobilization of sediments
at a beachface and formation of a beach ridge to the
landward translation of the coastal depositional body and,
then, to its transformation. An extreme acceleration causes
burial of the coastal depositional body by a transgressive
sedimentary sequence. Under the latter mobilization of
existing scarce sediments turns to a landward movement of
a depositional body, erosion of its seaward slope, drowning,
and partial destruction. The extreme acceleration
may bring, in some cases, the total grading of the coastal
zone profile. The series of responses can be interpreted in
terms of a turn from quasi-equilibrium to disequilibrium
evolutionary patterns.
Sediment budget of a coastal segment may be the dominant
factor in coastal evolution under sea-level changes,
notably in cases where there is either heavily excessive or
insufficient supply of sediment. Both situations may result
in a dominantly landward movement of sediments. Moderate
inclination of the undervater coastal slope is possibly
another precondition for such a response.
YOURI SELIVERSTOV
Genesis of exerational relief
Department of Geography and Geoecology
of St. Petersburg State University 10th lini 33,
Vasil'yevskiy Ostrov, St. Petersburg 199178, Russia
Glacial erosion or exeration is not an effective process; the
majority of exerational forming has another origin, like denudational,
crumbling etc. The proof of this observation
can be carried out in the mountains of central Asia, the Altai,
the Sayansk mountains, Tyan-Shan etc., where the cirques
and crust are not exerational forming. We can say
even more nowadays glaciers don't destroy, but bury some
friable forming different genesis, which happened to be
there. Under the glaciers which are going away appear some
friable forming of different crust of weathering. Moraine
and especially boulder material are only transported by
glaciers. They appear because of first of all denudational
processes. All these points allow us to estimate the meaning
of glacial regions in another way, for example by
seeking for· some minerals.
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PROBHAT KUMAR SEN
Gemorphology of the Lower Ganga Basin,
West Bengal, India
Department of Geography, Burdwan University,
Burdwan, 713104, West Bengal, India
Ganga basin, one of the largest deltas of the world, has
only 1/3 of its Western section in West Bengal, India. The
river Ganga at present flows only for a small length from
the NW to SE in West Bengal before flowing down to
Bangladesh Ganga (Padma) delta.
The genetic classification of the delta as moribund, mature
and active deltas portray some remarkable hydrographic
features, palaeo-geomorphic and present-day geomorphic
forms and processes which can be recognised after careful
study of its evolution, micro-relief, lithologs and riparion
features.
Ganga delta, a composite one, is formed by the coalescence
of a number of deltas built up by its tributaries and distributaries
of which one group are those flowing down the
Himalays and the others from the Chotanagpur plateau.
The surface topographic forms do not provide a ready clue
to the demarcation of each of them unless .lithology and
palaeo-geomorphic investigations are carried out.
The moribund delta in the north, formed of older alluvium
manifest higher relief and distinct pedogenic processes of
leaching and hydrographic features of dying channels, vulnerable
to floods, spill channels, meander scars, cut-offs,
chuts etc. The mature delta is formed of newer alluvium,
bearing the imprints of oscillating channels, extreme sinuosity,meander
scars, backswamos, cut-offs etc. With
vehement bank-side erosion and innundation creating hazards.
The southernmost part facing the sea front, south of
Calcutta is the active delta zone experiencing tidal phenomena
through the creeks and anastomostic drainage. Salinity
and siltation are serious problems
In this paper the different aspects of the delta geomorphology
and problems have been discussed.
MATTI SEPPALA
Geomorphological aspects of road construction
in cold environments, Finland
Physical Geography Laboratory
p.o. box 9 Fin-00014, Helsinki University, Finland
The traditional concepts of roads were chosen to follow
easy landscapes and suitable landforms. When the traffic
and the size and weight of vehicles increased' and higher
speeds were used it required more straight roads. That
meant that the easy going relief could not always be fol-