ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

two detailed raster Digital Elevation Models and is addressed
to identify uniform physiographic units and landforms
outstanding from the geologic and volcanic hazards viewpoint.
Differences and similarities between the two islands
will be outlined.
FIG. 1 - Sketch map of Santorini island.
FIG. 2 - Sketch map of Vulcano island.
ANTHONY J. PARSONS
Sediment-transport competence of rain-impacted
interrill overland flow on semi-arid hillslopes
Department of Geography, University of Leicester, University Road,
Leicester, LEI 7RH, U.K.
On semi-arid hillslopes soils are typically coarse-textured
and stony, so that the supply of sediment for removal in interrill
overland flow may be limited as much by the competence
of the flow as by its capacity. Although competence
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has been extensively studied in river flow, equations developed
in that context are inappropriate for predicting the
competence of rain-impacted shallow flow where sediment
entrainment is achieved dominantly by raindrop impact. In
order to obtain a suitable predictive equation for sediment
transport under these conditions, laboratory experiments
were performed using a recirculating flume 4.80 m long
arid 0.50 m wide with a bed of fixed silica sand (median
diameter 1.5 mm), Rain falling onto the flume was varied
in intensity between 51 and 138 mm h-\ flow was introduced
from a header tank into the flume at rates ranging
from 0 to 0.64 I S-I, and experiments were conducted on
flume gradients between 3.5 and 10°. Particles ranging in
size from 3 to 10 mm were introduced into the flows in the
flume generated under the stated ranges of rainfall, flow
and flume gradient and the median transport distances of
between 10 and 25 particles of each size were recorded.
These experiments show that high transport distances of
particles are achieved only when high values of rainfall
energy are combined with high values of flow energy. The
combined effect of the two energy sources on transport distance
appears to be multiplicative, rather than additive.
This multiplicative combination of the effects of the two
energy sources is expressed in the following general transport
equation which was developed from the experimen­
tal data:
M.L = (RE.FE)1.636
in which M is particle mass, L is distance moved in unit
time (ern min-I), RE is rainfall energy (J m' S-I) and FE is
flow energy (J m' S-I), and for which r 2 = 0.53. This equation
provides the first available' means for predicting sediment-transport
competence of interrill overland flow. The
equation is limited in its utility insofar as it has been developed
using quartz grains and takes no account of variations
in absorption of rain energy by natural ground surfaces.
lEAN-FRANCOIS PASTRE\ MICHEL FONTUGNE 2 ,
or ANNE GEBHARDT 3, VINCENT KRIER 1,
CATHERINE KUZUCUOGLU 1 , CHANTAL LEROYER 4 ,
NICOLE LIMONDIN-LoZOUET I & NADINE TISNERAT 2
The morphosedimentary evolution of the river valleys
in the Paris Basin (France) during the Late and
Post-Glacial: climatic and human impacts
1Laboratoire de Geographie Physique, Ura 141 Cnrs,
1 place Aristide Briand, 92195 Meudon Cedex, France
2 Centre des Faibles Radioactivites, avenue de la Terrasse,
91118 Gif-sur-Yvette Cedex, France)
3 Laboratoire d'Anthropologie, Umr 0153 Cnrs, Campus de Beaulieu,
35042, Rennes Cedex, France
4 Centre National de Prehistoire et Umr 9933, 38 avenue du 26eme R.I.,
24000 Perigueux, France
The study of the Late-Glacial and Post-Glacial evolution
of the river valleys in the Paris Basin has been realized in
the frame of the rescue programme of archaeological exca-