ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

cirque (hanging glacier) and valley type. On the [ara
Mountain, where the vast plain at 2200-2400 meters altitude
exists, a glacier of plateau type was developed.
BRIAN MENOUNOS
Holocene, debris-flow activity within the Colorado
Front Range
Department of Geography, University of British Columbia,
1984 West Mall, Vancouver, British Columbia, V6T 1Z2, Canada
Debris flows are an effective sediment transfer mechanism
within many alpine areas of the world. This statement was
recently tested within a mountain range of Colorado by
specifically: a) addressing their presence and geomorphic
significance within contemporary times; b) evaluating their
effectiveness through the Holocene Epoch.
Within this environment, debris flows occur preferentially
on southwest-facing slopes, west of the Continental Divide
in basins with relatively high ruggedness numbers. Magnitude
of the flows range from 100 to as large as 8000 m'
with a mean volume of 900 m', Recurrence intervals for individual
basins vary, but are generally less than 100 years.
An estimate for geomorphic work produced by annual debris
flow activity (1.69x10 6
Joules km yr") was calculated
as a means to quantify the effectiveness of debris flows in
surface denudation. When evaluated within the context of
other Front Range hillslope process rates, debris flows are
significant in alpine, landform development. Comparison
of this effectiveness with data from other mountain environments'
however, indicates that Front Range debris flow
activity is low and may be explained by lithologicand climatic
controls.
Given the evidence of Front Range, climate change within
the Holocene, past rates may show no relationship to contemporary
activity. A Holocene chronology of debris flow
activity for the Front Range Mountains was developed as a
means of comparing past and present effectiveness. Incorporation
of lichenometric, pedologic, and accelerator mass
spectrometry (Ams 14C dating of terrestrial deposits indicate
that debris flow activity coincides with recognized Neoglacial
activity during the late Holocene. A larger than expected
number of deposits date to the Audubon Glacial
Advance (1850-950 yr BP) and supports the contention
that hillslope instability is enhanced during times of climatic
deterioration.
A longer and more robust record of debris flow activity
exists within lacustrine sediments obtained from a Front
Range, alpine lake (Sky Pond). Fifteen Ams 14C ages provide
absolute ages for several debris-flow units and allows
estimates to be made on others through extrapolation. In
contrast to the terrestrial record, the largest and most numerous
lacustrine debris-flow laminae were deposited durirlg
a period of regional climatic amelioration (8000-4500
272
yr BP). Minimum sediment yield estimates for the catchment,
inferred from the accumulation of minerogenic matter
within the lake, was also greater than during late Holocene
time. This evidence, combined with re-interpretations
of previous sedimentary records from other depositional
environments in the Front Range, suggests that mid-Holocene
episodic sedimentation exhibited regional synchroneity.
Changes in debris flow activity and other forms of
episodic sedimentation were most likely driven by the onset
and availability of monsoonal inclusions into Colorado
during the Holocene and not due to the exceedence of
geomorphic thresholds. Unlike many alpine environments,
however, a correspondence between enhanced debris flow
activity and climatic amelioration exists for the Front Range.
Differences in precipitation regimes are the most likely
sources of this discrepancy and implies that alpine environments
will respond to future climate change differently.
GABOR MEZ6s1 & J6ZSEF SZATMARI
Assessment of the wind erosion activity on the Southern
Part of the Great Hungarian Plain
University of Szeged, Department of Physical Geography
H-6722 Szeged, Egyetem str. 2, Hungary
Wind erosion processes endanger nearly 23 ro of the total
surface of the Danube- Tisza Interfluve region. Thus it is
apprent that conservation of light sand soils against wind
erosion is vital, so much as privatization started in the first
years of this decade brought fundamental changes in facilities
of soil protection. In 80's a county-wide soil protection
network directed the resaech to reduce the damages. After
the privatization (1988-89) the landuse (type and structure)
was changed. The results of this process were overlapped
with the natural aridification tendency of the South
Hungarian Region. Both changes indicated us to launch a
research project with the following aims:
- to build up stations for measurements of deflation and
accumulation of sandy soils,
- to provide suitable information and advice for the private
landowners
- to asssess the risk of wind erosion in the Danube-Tisza
Interfuve region for the regional dvelopment plan..
In this study we would like to summerize last problem, to
border the territories endangered by wind erosion and also
to define the size of these areas. We marked out 64 km 2
large area around the stations. The monitoring methods of
the test area were elaborated. After collecting and meausring
of the geomorphological, soil and landuse characteristics
these data were transported to a database. The idea of
the analysis based on Gis and remote sensing methods. We
selected the surfaces covered by sandy soils, the surface
was used as cultivated area and posited not in the deprression
between sand dunes. There are the where the wind