ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

96, when approximately 500 mm of precipitation was registered
during three winter months. Channel flow lasted for
several months. Analysis of long-term data (1907-95) from
a meteorological station nearby show that only on three occasions
the rainfall total registered during a 3-month interval
exceeded the observed one.
The contrasting rainfall characteristics (i.e. high intensity,
short-term rainstorms versus continuous rainfall) produce
a complex catchment hydrology, which in term is responsible
of the highly variable sediment losses in the channel. A
simple relationship between rainfall, discharge and gullying
does not exist in the study area. The dominant process
is assumed to be surface erosion produced by running
water (pipes do not exist) as indicated by active headcut
retreat and lateral incision with subsequent bank collapses.
However, the importance of sediment humidity can not be
excluded.
BERNT SCHRODER
Human impact in Late Quaternary rift basin
geomorphology ofW-Anatoli a (Turkey), B. Menderes valley
Institut fur Geologie, Ruhr-Universitat Bochum,
Universitatsstr, 150, D-44801 Bochum, Germany
The fluvial systems of the Aegean coast in Turkey have
been operating since the Late Pliocene/Quaternary time.
The high influence of the west Anatolian rivers in shaping
the coastal configuration is due to the W-E-running horst/graben
tectonics at the eastern rim of Aegean Sea, influencing
both the direction and size of the catchment
areas as well as their high amount of easily erodable Neogene
sediments within the graben structures along the river
courses.
Intensive Late Holocene delta progradation is fairly well
known from some W-Anatolian rivers between Troy in the
Nand Kaunos in the S. The former «Latmian Gulf» in the
lower course of the B. Menderes valley is an area of extremely
rapid coastal change during the Late Holocene.
The human impact on the landscape in this area can be
traced and quantified by interdisciplinary field work and
in intimate contact with archaeologists. The increasing
growth of the «younger alluvial fan generation» as well as
that of the alluvial cones can be traced and dated by ceramics.
The data fit to stages of delta progradation.
i) Delta progradation since 5 ka
The flooding of the original marine embayment during the
Holocene sea level rise might have reached 60 km inland
from the present delta front.
The original contours of the Late Holocene Latmian Gulf
are under investigation. Data from water drillings indicate
Holocene marine strata below the fluvial delta plain reaching
50 km inland. The stages of the delta progradation
can be roughly reconstructed using archaeological data.
About 50 km' of suspended load have been accumulated
346
during Late Holocene time in the marine embayment this
giving rise to a prograding delta into its present position.
The onset of delta progradation seems to be intimately
connected with increasing human settlement since the
midth of the 4th millenium B.C..
The Holocene time-averaged fluvial sediment load is about
one tenth of that of Archaic to Early Byzantine time. At
present it is four times higher than «normal» and equals rivers
from areas of very high relief of low latitudes. The time-averaged
rate of mechanical erosion within the catchment
area (25.000 km') is about 0.5 m during the last 5 kyr.
ii) Late Holocene fan and slope deposits
The steep flanks of the Samsun Mts. at the northern rim of
the rift basin are bordered by many alluvial fans, some of
them coalescing. The main growth stages of these fans go
at least back to the last glacial marine lowstand. Afterwards
stream channels became entrenched into the fans.
The channels have been partly backfilled during the Holocene.
The thickness of alluvial fill in these young cones
may reach up to 6 m since Archaic time.
At the «normal» slopes of the smoother southern rim of
the rift basin late Holocene sheet flow deposits accumulated
in gently dipping alluvial cones from the Chalcolithic
period onward, reaching downfan thicknesses up to 6 m.
Gullying of slopes can be traced back to the Archaic period.
Intense slope wash and valley fills (up to 5 m) can be
older or even younger than Roman aqueducts.
iii) Environmental aspects
The early stages of deforestation and destruction/erosion
of soils in the area of Milet go back to the midth of the 4th
millenium B.C.. The most intensive human impact on the
landscape started during the Archaic period and lasted till
the Early Byzantine period.
LOTHAR SCHROTT
Water storage of permafrost in the semiarid Andes
Department of Geography, University of Bonn,
Meckenheimer Allee 166, 53115 Bonn, Germany
In many catchments of the semiarid subtropical Andes of
Argentina rock glaciers, as the visible expression of mountain
permafrost, are a widespread cryogenic phenomena
covering larger areas than glaciers do. Based on airphotograph
interpretation, geomorphological mapping and field
measurements (soil temperature, seismic soundings, discharge
measurements) the extent and hydrological significance
of high mountain permafrost is demonstrated.
Different approaches are applied in order to estimate
quantitatively the potential water store of permafrost bodies
and glaciers and to show how much meltwater they
constitute throughout the ablation period. On the basis of
an inventory, taking account of surface and thickness, the
potential ice content of glaciers and rock glaciers was cal-