ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

ien, il existe merne des cirques exposes plein sud Ie long
de lignes de crete de 1600-1700 m. L'intensite de l'englacement
est aussi attestee par des vallums situes jusqu'amoins
de 700 m d'altitude (5 cas) alors que Ie plus haut sommet
est de 1956 m.
Si 1'on suit la «methode des sommets» (Vergletscherungsfldcbe)
qui consiste a rechercher l' altitude minimale des
cretes ayant permis l'alimentation glaciaire, il existait done
un decalage de l'ordre de 400 m en moyenne entre la position
de la limite des neiges permanentes au-dessus des
Prealpes Francaises du Sud et de l'Apennin Septentrional.
La valeur plus basse de l'ancienne limite des neiges au-dessus
de l'Apennin Septentrional est en accord avec la repartition
actuelle des precipitations. II tombe 1228 mm par an
au sommet du Mont Ventoux contre plus de 2000 mm sur
les sommets de l'Apennin ligure ou de celui de Parme, et
merne bien plus de 3000 mm sur Ie coeur des Alpes Apuanes.
Ces abats d' eau de l'Apennin Septentrional s'expliquent
par sa position de premiere barriere montagneuse
face aux flux humides de SW associes a l'aire de cyclogenese
du Golfe de Genes. Les analyses palynologiques
confirment la nuance humide voire «oceanique» du climat
du maximum glaciaire du Wiirm recent: une sapiniere pure
recouvrait la plaine cotiere au droit des Alpes Apuanes
englacees,
LAWRENCE K. JEJE
Landuse changes and sediment yeld in parts
of central Western Nigeria
Department of Geography, Obafemi Awolowo University,
Ile - lfe, Nigeria
12, 3rd order basins were randomly selected from an area
of similar geology (quartzite-quartschists) and relief (ridge
and valley topography) in parts of Central Western Nigeria
noted for upland rice cultivation which has involved the
virtual transformation of a dry rain forest into contiguous
farmlands. The basins were monitored for 1 year with
emphasis on runoff and sediment yield.
The six forested basins had 55-81 % forest cover while the
farmed basins had 56-89% farm coverage. All the streams
were perennial. The farmed basins had significantly higher
values of specific suspended sediment yield at 3.7-46.5
tkm-2yr-1 and an average of 23.5 tkm-2yr-1 than the forested
basins at values ranging from 0.9 tkm-2yr-1 to 14.0
tkm-2yr-1 with an average of 6.6 tkm-2yr-1 of which
54.82 % were produced by Q1 storm runoff in contrast to
the farmed basins where most of the suspended sediment
yield were associated with Q10 and Q50 discharges.
Solute load was 0.75-15.9 times suspended sediment load
in all thebasins, averaging 7.91 times in the forested and
2.03 times in the farmed basins. Specific solute load varied
from 6.0 to 28.3 tkm-2yr-1 averaging 18.05 tkm-2yr-1 from
220
the forested basins and 6.7 to 42.6 tkm-Zyr-I and averaging
19.65 tkm-2yr-1 in the farmed basins.
With a mean of 26.8 m3 km-2yr-1 denudation rate is significantly
less in the forested than in the farmed basins with
a mean of 41.35 m 3 km-2yr-1(cf. Douglas 1967 a & b, in
the Cameron Hills of Malaysia).
VIBHASH C. IHA & U.K. MANDAL
Geo-engineering mapping of the Saintoli Gad Basin,
Garhwal Himalaya
Department of Geography, Visva-Bharati University, Santiniketan, India
In this paper, an attempt has been made to prepare a
geoengineering map of the Saintoli Gad basin, Garhwal
Himalaya, India. The Geoengineering map of basin warrants
geographical investigation for three main aspects, namely:
(i) existence of the drainage basin in the physical environment,
(ii) its relation with various geomorphological
processes, and (iii) its significance for human use. The
drainage basins are mainly characterized by geo-engineering
properties. Keeping the above facts into consideration
the Saintoli Gad has been mapped.
The engineering properties such as landforms, rock units,
tectnics, soil units and geomorphic processes (mass-movement
and erosion) have been examined. The investigation
also examines the joint spacing and rock mass strength of
various rock types found in the basin.
After superimposition of all above data, a geoengineering
map for the Saintoli Gad has been prepared. It is noted
that the basin is characterized by four terrain stability units
such as low, medium, high and very high, characterized by
joint spacing of 5-10, 10-25, 25-50 and 50-100 ern and
compressive rock strength of 650, 1100, 1350 and 3400
kg/ern' respectively. Applications of this map have also
been discussed.
PETER JOHANSSON-
Geomorphological evidences for the age of the esker
chains in NE Finnish Lapland
Geological Survey of Finland, p.o. box 77, FIN-96101
Rovaniemi, Finland
In the northeastern part of Finnish Lapland, at least three
crossing esker systems of various ages exist, two of them
till-covered. Weak glacial erosion and deposition prevailing
in the Weichselian ice-divide zone have made possible
the preservation of old esker ridges. These esker systems