ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

IRENEE HEYSE
The Middelkerke Sandbank in the Southern North Sea
(Flemish Banks, Belgian continental shelf)
Department of Geography, Physical Geography,
Research Unit of Marine and Coastal Geomorphology (Rumacog),
University of Gent, Krijgslaan 281-S8, 9000 Gent, Belgium
The Flemish Banks are a group of parallel sandbanks or tidal
current ridges (Off, 1993) situated on the French-Belgian
North Sea coast and streching in a SW-NE direction,
slightly oblique to the sandy macrotidal coastline. These
banks are separated by swales that dip to the NE and generally
do not reach below 30 m spring low waterlevel.
Their morphology has been studied by Van Veen (1936),
Off (1963), Houbolt (1968), Van Cauwenberghe (1971),
Caston (1972), Bastin (1974), Kenyon & alii (1981) De
Moor (198S), Ceuleneer & Lauwaert (1987), De Moor &
Lanckneus (1988,1989), Vlaeminck & alii (1989), Lanckneus
& alii (1989) and Heyse & De Moor (1996).
Each of these banks is about 20-30 km long, 10-20 m high
and 1-2 km wide. These dimensions and the general size
decrease to the east.
The Middelkerke Bank is the eastermost and the most shoreward
of the Flemish Banks. The coast is at a distance of
11-14 km (Middelkerke-Ostend section) and the bank has
a streamlined plan shape. The large-scale dimensions of
the bank can be summarized as follows: 10 km long, 1 km
wide, 10-11 m height, SW -NE orientation 36° north heading
ant an angle of 20° with the coastline (56° north heading).
The surroundings «deeps» have a more or less flat
bottom, the Negenvaam channel to the NW is 2 to 3 km
wide ant is 20 to 22 m deep, the Uitdiep to the SE is 1 to 3
km wide and 16 up to 19 m deep.
The cross-section of the Middelkerke Bank is typically
asymmetric, the NW flank being clearly steeper than the
SEC flank. The more or less flat top zone of the bank is situated
at -5 m and has a width of about 200 m The flank
profiles are mostly concave-convex with a middle slope
straight section. The most common bedforms are sandwaves,
subaqueous dunes of varying size and small scale
ripples.
In the framework of European Projects (Resecused and
Starfish), the Middelkerke Bank was selected to study the
morphodynamic evolution of the entire bank environment.
As well short time, medium term as long term evolution
was studied. Detailed investigations could be performed in
order to map in detail all the morphological bedform features
to monitor relevant near bottom sites in the watercolurnn,
to determine the hydrological conditions, to estimate
the impact of sand mobility and to evaluate the sand
budget evolution of the sandbank. Also the impact of extreme
storm events upon the bottom morphology was investigated
Results of the 6 year multidisciplinary programme are
presented.
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DAVID L. HIGGITT & ROBERT J. ALLISON
The form and development of slope profiles and boulder
pavements in the Eastern Badia, Jordan
Department of Geography, University of Durham, Durham,
DHI 3LE, U.K.
The Eastern Badia of Jordan includes 11 200 km 2 of arid
and semi-arid desert, where the ground surface has developed
on late Tertiary and Quaternary basalt lava flows. Topographically
the region has a maximum altitudinal variation
of around 800 m, with the highest ground in the
north-west on the foot-slopes of the Druz mountains. Locally,
differences in absolute relief between topographic highs
and lows are small, being no more than 10 m on the oldest
basalts but increasing to around 50 m for recent volcanic
centres where remnant extrusive cones are still evident.
The geomorphology of the Eastern Badia is dominated
by three characteristics. First, slope profiles which range
from concave to convex forms. Second, a rock boulder
cover across much of the ground surface, with distinct spatial
variations in the degree of boulder exposure.or burial.
Third, pans of fine grained sediment which accumulate at
topographic lows and are known locally as Qa and Marab.
Results are presented of a study which has investigated relationships
between basalt lava flow type and age, the form
of slope profiles and variations in the ground surface boulder
cover. As lava flow dissection occurs as a consequence
of landscape development, slope profiles change from convex
forms, characteristic of flows> 8.45 million years old,
to transects which are concave and characteristic of flows
< 1.45 million years old. The boulder cover variesbetween
the crest and the toe of slopes, the degree of exhumation
or burial providing an indication of the flux of fine grained
sediments as a consequence of sediment transfer processes,
particularly overland flow.
ANNE C. HINTON
Tidal changes and their consequences
School of Geography, Leeds University, LS2 9JT, Leeds, U.K.
Alterations to tidal levels are not necessarily the same as
those to mean sea level. Holocene tidal changes have been
shown to vary spatially in both magnitude and direction.
This situation is continuing at the present day and has wide-ranging
implications for future coastal development.
Man has had a significant impact on present trends by his
effect on nearshore zones.
An examination is made of tides in differing geomorphological
contexts to assess the impacts of coastal and offshore
morphology on the tidal regime. In open embayments, al-