ABSTRACTS / RESUMES - Comitato Glaciologico Italiano

trend (the Arsiani, Sarnsari, J avakheti). A specific type of a
volcanic relief with monogenic and polygenic volcanoes of
central type was formed with which. a great amount of
piroclastic material, lava sheets and lava flows are connected.
The age of volcanic relief is Mio-Pliocene (Sarmatian,
Meotian, Pontian) and Eopleistocene-Pleistocene) in the
South Georgian upland, and Antropogene in the central
part of the Greater Caucasus. The last volcanic eruption
in Georgia took place 6000 years ago in the Kazbek
massif.
STANISLAV A. MAKAROV
Soil avalanchings in theBaikal Region
Institute of Geography at the Siberian Division of the Russian Academy
of Sciences, Ulanbatorskaya str. 1,664033 Irkutsk, Russia
Soil avalanchings from slopes that occur in the mountain
ridge of Lake Baikal, refer to major natural catastrophes,
causing destructions of engineer constructions, Depending
on the geological structure of the slope sediments in the
Baikal Region, three types of soil avalanching are distinguished:
Type 1. Soil avalanchings forming in gently sloping narrow
gullies of the run-off in eluvial-deluvial sediments, having a
foliated structure (fig. a). Section of the sediments (from
top to bottom):
-'"" the first layer: gruss-detrital sediments, filler - sand
loam, content 30-40%, sand loam filtration coefficient
0.06-0.45 m/day, and layer thickness up to 0.6 m;
- the second layer: sand with inclusions of gruss and detritus'
sand filtration coefficient 2,-4 111/day, and layer thickness
from 0.5 to 5.0 m;
- the third layer: ledge rocks greatly decayed and seamy.
The filtration rate in the second layer is several times higher
than in the first; therefore, long-lasting and intense
rains give rise to ground slope run-off in the second layer
which produces a hydrodynamic upthrust of the first layer
in the lower part of the slope, as a consequence of which
water-saturated slope sediments go unstable, and soil avalanching
sets in.
Type 2. Soil avalanchings that form in glacial sediments
above their contact with solid rocks. Downward the slope
they transform to mudflows, with well-defined courses in
eluvial-deluvial sediments (fig. b).
Type 3. Soil avalanchings that form in valleys of temporary
water currents, with the thickness of loose sediments ranging
from 5 to 10 m (fig. c)
Because of the complicated and diverse character of the
natural conditions of the Baikal Region, as part of further
investigation the types of avalanchings identified here will
incorporate not only intermediate forms of soil avalan 'chings
but also, possibly, hew ones.
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