ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

with large amounts of large woody debris plotted within
the general field defined by data from bedrock reaches,
but were cobble/gravel bedded streams in the local low­
-gradient areas between the debris structures, a finding similar
to that reported by Montgomery & alii (1996) in the
Satsop River basin. Our findings show that (i) an area-slope
threshold generally defines bedrock and alluvial channel
morphology in Pacific Northwest channels, but that (ii)
regional differences in the threshold value appear to depend
on lithology, and (iii) variations in sediment supply
and the influence of large woody debris can locally
overwhelm these general trends.
GIUSEPPE MASTRONUZZI 1, GIOVANNI PALMENTOLA 1,
PAOLO SANSO 1, STEPHEN CROOKS 2, KENNETH PYE 2
& ANDREW THOMAS 2
Coastal cliff erosion in southern Italy and southeast
England: environmental controls
and management problems
1Dipartimento di Geologia e Geofisica,
Universita di Bari, via Orabona 4, 70125 Bari, Italy
2 Postgraduate Research Institute for Sedimentology, University
of Reading, Whiteknights, Reading RG6 6AB, UK
The erosion of coastal cliff is a process of fundamental importance
in a number of contexts including threats posed
to cliff top properties, the maintenance of sites of geological,
scientific and archaeological interest and the provision
of sediment to neighbouring beaches and other depositionalenvironments.
This subject is currently being jointly investigated
by English and Italian research teams with the
financial support of Crui and the British Council.
In southeastern Apulia, three contrasting examples of soft
cliff erosion are provided at Cerano, Otranto and Porto
Miggiano. The coastal area surrounding, Cerano is characterized
by a high cliff cut in clayey sands with a narrow
sand beach at its foot. Cliff evolution is dominated by mass
movements triggered by tension cracks and subsequent
weathering; wave action is responsible for the removal of
failed cliff material. Groynes and other defences works have
recntly been constructed to create a wide beach in front
.of part of the cliff which is backed by a power plant under
construction. The coast north of Otranto is characterized
by cliffs up to 15 m high developed in weak, layered calcarenites
which in several place are rapidly retreating due to
rock falls. Two main group of processes are responsible:
(1) weathering induce by seepage along strata planes combined
with wave action, and (2) cave formation and widening
with subsequent roof collapse. In the area surrounding
Porto Miggiano, south of Otranto, an indented cliff
up to 30 m high is developed in weak calcarenites. Cliff retreat
here is mainly by rock falls induced by wave impact
which loosens metre-scale rock block along major joints.
In several parts of eastern and southern England, soft cliff
composed of a variety of Tertiary and Quaternary lithologies
are eroding at rates of up to 2 m/yr. Actively eroding
cliffs were formerly much more extensive, but large sections
of coast have been protected by defence works
since the middle of the last century. Some section of coast,
e.g. between Weybourne and Happisburgh in northeast
Norfolk, now display an indented plan form due to differential
erosion between adjacent unprotected and protected
sections of cliff. In the softest lithologies, composed of
complex sequences of glacial till, sands and silts, cliff retreat
occurs due to a combination of land drainage and wave
undercutting of the toe slope during storms, leading to
large scale rotational slides and mudflows. Average rates of
recession over the past century have been 1-2 m/yr. On
harder lithologies, such as Chalk near Hunstanton in
northwest Norfolk, retreat occurs mainly by wave undercutting
and rock falls. Average rate of recession here have
been 6 m/yr) occur on cliffs composed of uncosolidated
and weakly consolidated sandy sediments as for
example at Covelithe in Suffolk. Currently, there is active
debate concerning whether such cliffs should be left undefended,
and, indeed, whether' existing defences should be
removed in some areas. Work currently in hand aims to
model the likely pattern of cliff evolution in different lithology
and wave energy settings which may follow removal of
defences.
NIKOLAJ MASYUK, NIKOLAI KHARITONOV
& VALENTIN P ASHOVA
The assessment of major and trace elements' migration
in conditions of steppe landscape
Agroecology Institute, Dniepropetrovsk Agrouniversity,
25 st. Voroshilov, Dniepropetrovsk, 320027, Ukraine
Investigation of typical for centre of Ukraine steppe the
landscape has been done.Slopes with steepness 1,5 degree
had weak -expressed erosion soils. Slopes with steepness
1,5-7 degree had washed off upper horizon of humus more
than 2 time.
It was established that nitrogen and phosphorus contents
in the slope soils were 1,5-2 times lower that in plain.Erosion
of soils leads to reduction of heavy metal concentration
too.The content its elements was Ni 5,2-9,7, Cr 1,4­
5,0 and Pb 8,6-11,1 mg/kg. We have showed that number
of ammonificatedmicroorganizms on the sunlit slopes was
1,5-2 times bigger than on the shady slopes.
The investigations of effectiveness of new fertilizers' forms
were conducted in the conditions of greenhouse and field
experiments. Results of field experiments have showed
that increasing of barley yield from polymer-based fertilizer
use was 0,5 ton/ha on the plain and 1,0 ton/ha on the
slope.
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