Anisirrwv and Posvelov: The Landscape and Geobotanical Characteristics
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communities, but by stable and unstable primitive plant aggregations.
The physico-geographical characteristics of the research area
The Levinson-Lessing Lake basin is situated in the central part of the Taimyr peninsula, within
the limits of the Glavnaya Range in the Byrranga mountains. The centre of the territory is
located at 74° 30' N and has an area of about 500 km 2 . The elevation ranges from 47 m a.s.l. at
the lake surface up to 568 m. a.s.l. The average height of the mountains is about 300 m a.s.l.
and mountains occupy not less than 80 % of the territory. To the north, the Krasnaja river
enters the lake through a low-lying peatland plain, 5 km wide, influencedby ancient terraces and
bedrock outcrops. The lake is drained by the short (less than I km) Protoczny stream, which
flows into the Ledjanaja river and further on into Ledjanaja Bay of Taimyr Lake.
Geological structure and relief
The Byrranga mountains, running parallel to the northern coast of the Taimyr peninsula for
more than 1000 km, arose during the Hercynian (Palaeozoic) orogeny and have, since then,
undergone repeated tectonic dislocations, resulting in their current folded block structure. The
most common bedrock types are auleurolites. Dolerite, gabbro-dolerite and diabase intrusions
are also common, often in the form of weathered outcrops, and comprise the crests of ranges
and ledges. There are a few limestone plateaus, hardly weathered as a consequence of the low
mechanical durability of the bedrock. Traces of ancient karst are evident. Such deposits are
more widely distributed outside the lake basin, especially in the Levly river region, and often
adjoin coal slate outcrops. Tectonic dislocations are displayed through faulting, and are easily
distinguished on space photographs. The largest of the breaks is the Levinson-Lessing Lake
basin. This break is observed further southwards (Nedi Lake), and northwards (the valley of
the Zamknutaya river). The second largest break is the valley of the Krasnaja river. It is almost
rectilinear and runs parallel to the Glavnaja Range. Some small valleys (for example, the
Wresanny stream) may also be related to tectonic structures.
In the Quaternary, the territory was exposed to glaciations. The question of what type of ice
cover existed (ice sheet or alpine) and when the last glaciation occurred remains open. The
discovery of buried glacial ice with terminal moraine material in the Zamknutaja river valley is a
clear indication of glaciation. At modern scales of proluvial accumulation, alluvial fans of some
water channels could not have been generated (with respect to their current size and capacity);
hence, it is possible to assume that they were formed during deglaciation, when drainage was
large enough to explain the depositions. The degree of entrenchment of small valleys, even
those not affected by tectonic structures, is indicative of high speed deglaciation. On the other
hand, significant moraine and fluvioglacial deposits were not found anywhere (with the
exception of the afore-mentioned cases). Ancient terraced platforms are observed along the
entire lakeshore. There are up to 13 levels, the most easily distinguished of which lie at an
elevation of 100-120 m a.s.l. They usually resemble hills with flat tops, composed of rolled
and sometimes calcified pebbles.
Outside the lake basin, a significant portion of the flat surface of these terraces was preserved
in the Ledjanaja riverbed. This terrace fragment has a residual block structure (thermokarst with
an ancient network of ice lodes), demonstrating that its formation preceded active permafrost
processes. Proceeding from the foregoing, it is possible to rather confidently assert that the last
glaciation of Central Byrranga was alpine or even exclusively niche glaciers. and that it was
preceded by a significant marine transgression. Until now, the last glaciation was thought to
have been covering or half-covering (reticulate) (Antropogen of Taimyr, 1982: Strelkov, 1965;
Taimyr-Severnaja Zemlja region, 1970). Nevertheless, small niche-glaciers may have existed in
309
communities, but by stable and unstable primitive plant aggregations.
The physico-geographical characteristics of the research area
The Levinson-Lessing Lake basin is situated in the central part of the Taimyr peninsula, within
the limits of the Glavnaya Range in the Byrranga mountains. The centre of the territory is
located at 74° 30' N and has an area of about 500 km 2 . The elevation ranges from 47 m a.s.l. at
the lake surface up to 568 m. a.s.l. The average height of the mountains is about 300 m a.s.l.
and mountains occupy not less than 80 % of the territory. To the north, the Krasnaja river
enters the lake through a low-lying peatland plain, 5 km wide, influencedby ancient terraces and
bedrock outcrops. The lake is drained by the short (less than I km) Protoczny stream, which
flows into the Ledjanaja river and further on into Ledjanaja Bay of Taimyr Lake.
Geological structure and relief
The Byrranga mountains, running parallel to the northern coast of the Taimyr peninsula for
more than 1000 km, arose during the Hercynian (Palaeozoic) orogeny and have, since then,
undergone repeated tectonic dislocations, resulting in their current folded block structure. The
most common bedrock types are auleurolites. Dolerite, gabbro-dolerite and diabase intrusions
are also common, often in the form of weathered outcrops, and comprise the crests of ranges
and ledges. There are a few limestone plateaus, hardly weathered as a consequence of the low
mechanical durability of the bedrock. Traces of ancient karst are evident. Such deposits are
more widely distributed outside the lake basin, especially in the Levly river region, and often
adjoin coal slate outcrops. Tectonic dislocations are displayed through faulting, and are easily
distinguished on space photographs. The largest of the breaks is the Levinson-Lessing Lake
basin. This break is observed further southwards (Nedi Lake), and northwards (the valley of
the Zamknutaya river). The second largest break is the valley of the Krasnaja river. It is almost
rectilinear and runs parallel to the Glavnaja Range. Some small valleys (for example, the
Wresanny stream) may also be related to tectonic structures.
In the Quaternary, the territory was exposed to glaciations. The question of what type of ice
cover existed (ice sheet or alpine) and when the last glaciation occurred remains open. The
discovery of buried glacial ice with terminal moraine material in the Zamknutaja river valley is a
clear indication of glaciation. At modern scales of proluvial accumulation, alluvial fans of some
water channels could not have been generated (with respect to their current size and capacity);
hence, it is possible to assume that they were formed during deglaciation, when drainage was
large enough to explain the depositions. The degree of entrenchment of small valleys, even
those not affected by tectonic structures, is indicative of high speed deglaciation. On the other
hand, significant moraine and fluvioglacial deposits were not found anywhere (with the
exception of the afore-mentioned cases). Ancient terraced platforms are observed along the
entire lakeshore. There are up to 13 levels, the most easily distinguished of which lie at an
elevation of 100-120 m a.s.l. They usually resemble hills with flat tops, composed of rolled
and sometimes calcified pebbles.
Outside the lake basin, a significant portion of the flat surface of these terraces was preserved
in the Ledjanaja riverbed. This terrace fragment has a residual block structure (thermokarst with
an ancient network of ice lodes), demonstrating that its formation preceded active permafrost
processes. Proceeding from the foregoing, it is possible to rather confidently assert that the last
glaciation of Central Byrranga was alpine or even exclusively niche glaciers. and that it was
preceded by a significant marine transgression. Until now, the last glaciation was thought to
have been covering or half-covering (reticulate) (Antropogen of Taimyr, 1982: Strelkov, 1965;
Taimyr-Severnaja Zemlja region, 1970). Nevertheless, small niche-glaciers may have existed in