Relief and
geological structure
The geological
structure of the
gigantic region,
including the
north-western coast
of the Taimyr
Peninsula, the
islands of the
south-eastern part
of the
Kara
Sea and a considerable
part of the adjacent
water area, is
complex and diverse.
It is therefore
advisable to look
separately at the
geology and relief
of the islands,
lying far in the sea
(Uedineniya,
Sergueya Kirova,
Voronina, Izvestiy
TSIK, Sverdrup), and
of the north-western
coast of Taimyr –
from the Pyasina
delta to the
Chelyuskin Cape; the
latter incorporates
also the numerous
islands which are
located not far from
the continental
coast – the Minina
Skerries, the
Nordensheld
Archipelago and
others.
Islands of the
south-eastern part
of the
Kara
Sea.
Three large
stratigraphical
complexes can be
singled out in the
structure of the
islands of the
south-eastern part
of the
Kara
Sea: Proterozoic,
Cretaceous and
Quaternary (Dibner,
Zakharov, 1970). The
rocks of the Middle
and Upper
Proterozoic make up
the
Izvestiy
TSIK Islands
(Adler, Ul, 1936).
The rock strata are
transpierced with
numerous up to
2 m
thick quartz and
quartzite lodes. On
the gently sloping
upland of the
islands` central
part these rocks are
covered with brown
swampy loam with
detritus. No erratic
boulders and glacial
sediments have been
found on the
Troinoy
Island.
The relief of the
Izvestiy TSIK
Archipelago is
formed by two stages
of 35-
40 m
and 16 -
23 m
high
geotectonic-denudating
plains, a 5 –
13 m
high 1st
socle marine terrace
and a
2.5 m
high modern marine
terrace. The larger
islands – Troinoy
(the maximum height
–
42 m)
and
Pologuiy-Sergueyeva
(26
m)
are gently-sloping
dome-shaped uplands
with numerous rocky
precipices and
ridges in the
central part. Each
island consists of
several such
massifs, connected
with each other with
low marine terraces.
The maximum height
marks are found on
the ridges. The
300 m
long and up to 120
wide ridges are
placers of boulders
up to
3 m
across. There is a
bird colony on one
of such ridges,
situated along the
seashore (Romanenko
and others, 1994).
The intensity of
denudating processes
on the
Troinoy
Island
is at the present
time quite low. The
relief creating role
of erosion, deluvial
wash-off and
nivation is most
noticeable. The
majority of the
erosive forms are
70-100
m
wide hollows without
a flow bed with
slightly sloping
banks and detritus
bottom sides. Their
depth does not
increase 0.5 –
1 m.
In spring the
hollows are filled
with a snow and
water mass (“nyasha”).
The only
canyon-shaped
ravine, at the
bottom of which
3 m
high drifted snow
remains during the
entire summer, is
located to the west
of the
Polusotenny
Cape.
Bedrocks have been
found at the bottom
of the ravine.
Low Cretaceous
aleurites with sands
and lenses of brown
coal, interlayers of
limestone with
calcite and
silicified wood are
widespread on the
islands: Isachenko,
Uedineniya, Arctic
Institute and
Sverdrup. A jugular
vertebra of a
Plesiosaurus, found
on the Uedineniya
island, indicates
the coastal genesis
of the sediments.
Upper Cretaceous
aleurites and sands
with small pebbles
and gravel are found
on the Sverdrup and
Arctic
Institute
Islands.
Quaternary sea
sediments build up
lower terraces with
the height of 7-10
m
and 2-4
m
on the islands:
Izvestiy TSIK,
Uedineniya and
Arctic Institute.
Pebbles and detritus
of local rocks
prevail in their
structure on the
Izvestiy TSIK
Archipelago, on
other islands –
well-sorted sands
and silty-sandy
sediments with
Macoma
baltica and
Seppiros
groenlandicus
shells.
The relief of the
islands in the
south-eastern part
of the
Kara
Sea
is not notable for a
great variety. There
are mostly plains of
different origins,
rising 20 –
50 m
above the sea level.
The exception is the
islands: Zapadny
Kamenny, Rastorgueva
and Morzhovy,
located in the
Pyasinsky
Bay.
Their heights reach
respectively 159.4,
134.1 and
86 m.
They are steeply
sloping
geotectonic-denudating
uplands (Pogrebitsky,
1970).
Up to 30% of the
area of the
Sverdrup
Island
is covered with up
to
2 m
high sandy marine
terraces. The island
is surrounded by
vast sand banks. In
the centre of the
island there is a
22-28
m
high erosive plain,
lowering in the
south and south-west
to 12-18
m.
It is built up by
sandy and clayey
sediments, rumpled
in folds in the west
of the island.
Erratic boulders and
blocks of
3 m
across are
widespread there.
The prevailing rocks
among them,
widespread in the
Minina Skerries and
the Nordensheld
Archipelago, are
granites, diorites,
gabbro and
gneiss-granites.
A buried peatbog was
found in a 7-12
m
high precipice in
the northern part of
the island. The peat
accumulation began
about 11 900 year
ago and stopped
about 9 500 years
ago (Tarasov and
others, 1995). The
results of the
peat`s investigation
indicated that there
was no covering
glaciation on the
shelf of the Kara
Sea in the Late
Pleistocene. The
coastal lowlands and
vast areas of
dewatered shelf
were, apparently, at
that time the area
of manifestation of
active congelation
and eolithic
processes. Polygonal
lode ice of low
thickness was being
formed. Erosion,
deflation and
diluvial wash-off
prevail among other
erosive and
denudating processes
on the
Sverdrup
Island.
The island is
intersected with
numerous valleys
with symmetrical
transversal profiles
and weakly turfed
slopes.
The Russkiy Island,
the second largest
in the Nordensheld
Archipelago (309
sq.m), is built up
by metamorphosed
shales, sandstones
and aleurolites of
Early-Middle
Proterozoic (Pogrebitsky,
1970), overlapped
with thin (up to
2 m)
eluvial and deluvial
dry dense loam with
a large (up to 50%)
share of detritus
and gravel. There
are a lot of erratic
boulders, blocks of
granite,
gneiss-granites and
quartz with the
diameter up to
2 m.
The island is a
dome-shaped upland
with a shorter and
steeper western
macroslope and a
longer and flatter
eastern slope. The
top surface with the
height of 30-39
m
is disturbed with 1-2
m
deep flowless
hollows with the
diameter up to
1 km.
In the south-east
there is a 7-8
m
geotectonic bench,
broken by gullies –
the Upper Medvezhy
Brook. In the
north-west the top
surface slighty
lowers towards the
sea, in the
south-east it is
adjoined by
sub-horizontal 17-26
m
high sections, on
which two 3-4
m
deep kettles with
very humid bottoms
are located. The
lower south-western
part of the island
is a 9-14
m
high flat terrace.
The
Arctic
Institute
Islands
is an erosive plain
with 8-12
m
and 18-25
m
high sub-horizontal
sections and 4-7
m
and 0-1.5
m
high marine
terraces. There are
practically no
brows; the steepness
of the slopes,
practically deprived
of vegetation,
amounts to 2-5
degrees. The
Bolshoy
Island is made up on the
surface by
fine-grained sands
and numerous erratic
boulders and pebbles
of different rock
kinds.
On the
Voronina
Island
two terraces of the
supposedly sea
origin with the
heights of 4-8
m
and 10-17
m
can be singled out.
They are connected
with beach sections.
The
Isachenko
Island
is considerably
higher (57
m).
It is the larger
island in the
Sergueya Kirova
Archipelago. The
surfaces with the
heights of 2-5
m,
12-18
m,
30-40
m
and 45-50
m
can be singled out
there. On the
Slozhny Island, the
second larger in the
Archipelago, the 10-18
m
high surface is
broken by a dense
(2.08 km/sq.km) net
of gullies and is
cut by a canyon-type
brook valley with
geotectonic benches
on the slopes. The
5-10
m
high terrace,
supposedly of the
sea origin, is
practically
unbroken. There are
numerous erratic
boulders on the
Kirova and
Voronina
Islands (Dibner, Zakharov,
1970).
In the western part
of the
Uedineniya
Island
(maximum height –
27 m)
the very first
explorers (Gakkel,
1934; Serguyev,
1934) marked out an
elevated
gully-broken and
sea-destroyed
surface with the
height of 20-27
m.
The eastern part of
the island is taken
up by a 2-3
m
high marine terrace.
The western part of
the island is being
intensively
destroyed. Already
in
1939 a
residential house,
built in 1934, was
subjected to an
immediate threat,
and was carried
9 m
away without being
dismantled. In 1942
it had to be moved
to a new place
again. As the
seashore was
destroyed, the
number of nests of
the gulls, living on
it, also decreased.
In 1943 one of the
lakes was
transformed into a
bay after a storm,
the water level
dropped by
0.5 m
and geese stopped
nesting on it. (Nazarov,
1948).
The
Sibiryakova
Island can be with a
sufficient
confidence
attributed to
alluvial plains; the
major part of it is
taken up by
sub-horizontal caps
with the heights of
11-16m and 20-30
m.
They have mostly
turned into swamps
or lakes, are
covered with
polygonal soils and
fall to the sea as
12 m
high benches. The
island`s seashore is
being intensively
destroyed.
The underwater
foundation of the
majority of the
islands is the
Central
Kara Plateau.
The Izvestiy TSIK
Archipelago is a
fragment of the pre-Kambrian
Kara Massif, which
was not subjected to
the Late Hersynian
Plication. In the
Early Pleistocene
the
Kara
Sea
islands were
subjected to small
plicate-dumping
movements, the
traces of which have
been found on the
Kirova and
Uedineniya islands.
In the Late
Pleistocene the
Central
Kara
Plateau was subjected to
continental
glaciation. Since
the maximum depths
around all the
islands nowadays do
not exceed
50 m,
we can affirm that
they were connected
with the Continent
during the peak of
the Sartansk
regression at the
end of the Late
Pleistocene.
The north-western
coast of
Taimyr.
The islands of the
Taimyr Shoal and the
north-western coast
of
Taimyr
have a similar
geological
structure. Here we
can single out
Archean, Proterozoic,
Paleozoic (Kambrian
– Early Permian),
Cretaceous and
Quaternary
stratigraphical
complexes. Vast
gangway sills were
formed here as a
result of an
intensive volcanic
activity at the end
of the Upper
Permian.
Archean and
Proterozoic
gneisses, shales,
tuffites, sandstones
and conglomerates
are widespread at
the coastal section
from the Nordensheld
Archipelago to the
Minina Skerries.
A complex of marine
Kambrian-Lower-Permian
limestones and
shales lies on them;
it is overlapped
with a carboniferous
complex of Permian
lagoon-continental
and continental
sediments. The
productive layer
ends with a volcanic
complex of the Late
Permian – Early
Triassic. Early
Cretaceous sediments
are quite developed
on the
Chelyuskin
Cape
(Markov and others,
1957).
In the northern part
of Taimyr Upper
Quaternary sediments
are widespread.
Among them we can
single out marine
sediments of boreal
transgression,
Zyryansk glacial,
Karginsk lake-aluvial
and Sartansk glacial
sediments.
The sediments of the
boreal transgression
are 50-60
m
thick. Among the
sediments of
Zyryansk age with
the thickness up to
60 m
we can single out
proper glacial
sediments (moraine),
water-glacial and
lake-glacial
sediments. The
water-glacial
Zyryansk layers are
represented by silty
sands and sandy
boulder loams.
The above-lying
sediments of the
inter-glacial age
have a number of
typical
characteristics: a
large (several
meters thick) peat
layer, numerous
inclusions of bones
of animals –
representatives of
the “Mammoth Fauna
Complex” – mammoth,
musk-ox, bull,
reindeer; thick
polygonal lode ice.
The predominant
opinion before was
that these sediments
were of the sea
origin, but nowadays
the majority of
researchers tend to
acknowledge them as
those of the lake-aluvial
origin.
One can often come
across
pebble-detritus
conical and
semi-spherical
ridges and hills in
the Taimyr
mountains, at the
height of more than
80 m.
These formations
reach sometimes the
height of 10 –
15 m.
The impression is
that some of them
were created by
means of a directed
pressure from
outside. This is
also indicated by
the folds located in
the sand-and-pebble
sediments. Their
formation could be
caused by a pushing
action of the
Sartansk glacier.
There were vast
glacier-bordering
lakes during the
Sartansk glaciation.
6-8
m
high marine
terraces, formed
predominantly by
pebbles, are
widespread at the
seashore. Eluvial
sediments and
various types of
slope sediments
mostly of a
large-fragmented
composition are very
widespread in the
mountains.
The history of
development of the
accumulative relief
of North-Western
Taimyr consists of
three main stages of
its active
formation:
Kazantsevsk,
Zyryansk and
Karginsk, when the
appearance of the
territory and the
composition of the
sediments, forming
it, changed
considerably. The
Sartansk and
Holocenic Periods
made the relief more
complex, having left
the appearance of
its main features
almost without
alteration. The
history of the
relief`s development
became more complex
by the way of uneven
block-type tectonic
movements.
The leading modern
geomorphological
processes are river
thermoerosion,
deluvial wash-off,
solifluction, bald
mountain levelling
and a number of
glacial processes:
nivation,
thermokarst,
swelling, frost
induced cracking. A
staircase of
mountainous terraces
has been formed in
the mountains.
The territory of the
Great Arctic Nature
Reserve is included
in the
goemorphological
province “North of
Middle Siberia” (Geomorphological
division of the
USSR, 1980). Within
the bounds of
Taimyr`s continental
part there are two
geomorphological
districts:
Pyasino-Taimyrsky
and Chelyuskinsky
with the prevailing
hilly relief, the
absolute heights
reaching 350-400
m.
The islands of the
Taimyr shoal are
included in the
shelf Taimyr
sub-area.
The continental part
of the Nature
Reserve is mostly
situated within the
bounds of the
territory of the
Kara mountainous
massif. Within the
bounds of the area
“Upland Region
Byrranga” V.M.
Makeyev (1970) has
marked out a hilly
upland denudating
plain with an
intensive glacial
manifestation, the
gently-sloping wavy
accumulative
Leningradskaya
depression and a
plateau, as well as
a hilly upland
geotectonic
denudating plain of
the
Chelyuskin
Cape.
These sub-districts
are included in the
Kara massif, the two
sections of which
are divided by the
Leningradskaya
depression. The
relief is formed
here by large hills,
ridges and upland
with the traces of
glacial activity and
divided by erosive
hollows. The latter
often have a shape
of a trough.
Abrasive marine
terraces of various
heights are present
in the coastal area.
The abrasive-exarative
lowland of the
Khariton
Laptev
Coast and the sculptural-accumulative
lowland of the
Chelyuskin
Cape belong to
gently-sloping wavy
lowland coastal
plains. Their
characteristic
features are: a
small absolute
height, the
alternation of
upland and lowland
and a stage
structure. The
surface of the 2-3
m,
7-8m, 12-15m and 20-30
m
terraces is made
more complex by
smaller forms of
mezzo- and
micro-relief:
ridges, knolls,
hillocks, pebble
hills, geotectonic
soils and polygons.
The relief of
North-Western Taimyr
has been developing
during a long period
of time, denudating
processes
prevailing.
Therefore, this
territory is noted
for rather thin
layers of friable
sediments (the first
several tens of
meters), which can
mostly be found in
hollows and
depressions. The
most significant
factors of relief
transformation in
the Pleistocene were
block and rupture
tectonics, sea level
fluctuations,
glaciations, as well
as a complex of
denudating and
sloping processes:
weathering (mostly
physical),
cryoplanation,
landslide and
crumbling processes
and solifluction.
There were two
glaciation periods
in the Pleistocene
and one in the
Holocene.
The Zyryansk
and Sartansk Late
Quaternary
glaciations were
divided by the
Karginsk warming,
during which the
lake-aluvial plain
conditions were
prevailing on the
majority of the
territory. The
Zyryansk glaciation
had a semi-covering
nature and vast
glacier-bordering
lakes appeared at
the end of this
period. The Sartansk
glaciation had a
mountain-valley
nature.
The modern relief of
the Kara Sea islands
is developing under
the influence of the
Sea`s activity,
considerable parts
of the islands being
washed out.
Low-intensive
denudating processes
and river erosion
are prevailing in
the mountainous part
of Taimyr. The
majority of the
investigated
territory is taken
up by geotectonic
and
geotectonic-denudating
plains with the
traces of glacial
influence; on the
seashore – by
sculptural-accumulative
and abrasive-exarative
lowlands.
Permafrost
Multi-year frozen
rocks are widespread
on the whole
territory of the
Great Arctic Nature
Reserve. This
territory belongs to
the Northern
geocryological zone
of Middle Siberia (Geocryology
of the USSR, 1989).
The thickness of the
multi-year frozen
rocks reaches 500-700
m
in valleys and 200-300
m
in interfluves; in
Western Taimyr
ridges – 700-900
m
and 300-500
m
respectively. The
temperatures of the
frozen sequence vary
from – 7 to – 9o
C, in the
mountains they reach
– 11 – (-13) 9o
C. Detritus-block
rocks with
loamy-and-sandy-loamy
enclosures and
lentil-type latticed
and basal cryogenic
textures prevail
among sincryogenic
deluvial-aluvial and
sloping formations
with the thickness
of not more than
5 m.
Separate ice
lenticles can be
found in cracks and
clearances between
rock blocks. The
general ice content
is 20 to 60%. Ice is
usually found in the
form of lenticles
and inter-layers in
the lower part of
the sequence.
Intermontane
depressions and
river valleys are
overlapped with
loamy sediments with
thin ice lodes. We
can presume that
deep taliks were
formed under the
valleys of the
larger rivers –
Pyasina and
Nizhnyaya Taimyra.
Pre-quaternary (Archean
and Paleozoic)
bedrocks, widespread
on the territory of
the Nature Reserve,
also belong to
frozen rocks. The
total ice content of
the rocks does not
exceed 2-15%.
Peculiar ledges of
underground ice are
formed on the
islands. Thus, on
the
Russkiy
Island in the Nordensheld
Archipelago a loam
layer with
underground ice was
formed on the cap of
the shales and
sandstones of the
Proterozoic.
1 m
thick ice lodes were
found in the bank
steeps build up by
frozen bluish
grey-green loams
with detritus and
gruss in the north
and north-east of
the island. Apart
from it, numerous
ice inter-layers and
lenticles, up to
10 cm
long and 3-4
cm
thick, can be found
in the loam sequence
with a lentil
cryogenic texture.
Small thermokarsts
and thermocirques
are formed on the
ice inter-layers and
lenticles.
Numerous
2 m
thick ice lodes open
up in bank steeps of
the
Farvaterny
Island
and the islands of
the Pyasina delta,
which are built up
by sandstone and
loam sediments.
Thus, underground
ice of different
kinds can be found
on the islands near
the Taimyr coast:
polygonal-lode,
segregational,
ice-cement and
sublimational. There
are practically no
injection and layer
ice. Schlieren and
lenticles of
segregational ice
are the most
widespread. On the
islands built up by
bedrocks (Russkiy,
Izvestiy TSIK) and
overlapped with
eluvium one can find
ice deposits, which
were apparently
formed as a result
of the burial of sea
ice and firns, and
also their
subsequent
re-crystallization.
Climate
The weather
conditions of the
Great Arctic Nature
Reserve are notable
for their
considerable
variability from
year to year.
However, there are
general
consistencies of
temperature and
precipitation
distribution on the
territory of the
Nature Reserve,
preconditioned by
the character of
atmospheric
circulation above
the
Kara
Sea.
Thus, July 1987 was
at all the stations
generally cold,
whereas August 1990
– warm and humid.
The period since
1986 till 1991 was
rather dry and cold
in the south-eastern
part of the
Kara
Sea
and in the
north-western coast
of
Taimyr.
In winter the winds
of southern bearing
(southern,
south-western and
south-eastern)
prevail, in summer –
north-western,
northern and
north-eastern. At
the
Chelyuskin
Cape winds blow in summer mostly along
the
Vilkitsky
Strait,
western and eastern
directions being
predominant.
On the
Izvestiy
TSIK
Islands north-eastern and
eastern winds
prevail, western
winds blowing very
seldom. Still
weather occurs only
in 8.9% cases. The
average wind speeds
do not change by the
direction very much.
The strongest winds
are south-western,
southern and
northern (6.8
m/sec), the weakest
– eastern (5.7
m/sec). Summer and
autumn are the most
stormy time on the
islands. Thus, July
1992 numbered 19
days with a wind
stronger than 10
m/sec and 5 days,
when the wind speed
exceeded 15 m/sec.
At the same time,
there were only six
relatively calm
days, when the wind
was not stronger
than 5 m/sec. In
fact that was a very
cold year, the
average July
temperature
amounting only to
0.7oC.
Analyzing the
distribution of the
annual precipitation
amount we can draw a
conclusion that it
is not only
determined by the
character of
atmospheric
circulation, but
also by
microclimatic
peculiarities of the
area of the
station`s location.
The fluctuation of
the average
multi-year annual
precipitation
amounts between the
station reaches
140 mm
(in summer time –
much lower). The
maximum amount of
precipitation (390 –
400 mm)
falls on the
southernmost island
–
Dixon,
in the vicinity of
which open water
remains for a long
time. The minimum
precipitation amount
(259 –
270 mm)
is noted on the
Uedineniya
Island,
located at open sea.
In the warm season
the maximum
precipitation falls
on the
Dixon and
on the
Pravda
Island,
located in the
southern part of the
Nordensheld
Archipelago. The
smallest amount of
precipitation falls
on the
Izvestiy
TSIK Islands
and the
Chelyuskin
Cape. This can probably be
explained by the
fact that it falls
predominantly in the
form of drizzling
and not raining.
Thus, in July 1992
the precipitation
was noted on the
Troinoy
Island
during 17 days, but
its monthly amount
turned out to be
only
26 mm
– much lower than
the average
multi-year value.
Hard precipitation
can fall the whole
year round
practically
everywhere, and in
summer hard and
liquid precipitation
often alternate. In
the case of in-blows
of warm tropical air
torrential rains
occur, very seldom –
also with
thunderstorms. Fogs
and drizzling are
often observed in
summertime on the
islands and at the
seashore.
Snow covers the
tundra usually in
late August – early
September, but the
steady snow cover
forms in mid-late
September. The
northernmost parts
get covered with
snow earlier than
the southern ones.
The snowless period
is the longest on
the
Dixon
(103-110 days). The
snow lies the
longest on the
Chelyuskin
Cape
(300 days). On the
Nordensheld
Archipelago the snow
cover usually forms
earlier and stays
longer. The complete
melting of the snow
usually takes place
in late June – early
July.
The average height
of the snow cover is
not large due to
strong winds,
blowing it away from
the tundra surface.
The average maximum
value of the snow
cover height is the
largest (45-50
cm)
on the Russkiy and
Izvestiy
TSIK
Islands and also on the
Chelyuskin
Cape.
The maximum
thickness of the
snow cover is noted
on the
Uedineniya
Island
and the
Pravda
Island
(30 –
31 cm).
Rivers and lakes
North-Western Taimyr
belongs to districts
of excessive
humidity. Due to an
immense thickness of
multi-year frozen
rocks there is
practically no
filtration here, and
water remains on the
tundra surface,
forming numerous
lakes. This
territory has also a
dense river network.
The largest rivers
are Pyasina (length
–
818 km,
basin area – 182 000
sq km, average
velocity – 2600 –
4000 cu m/sec,
stream flow – 86 cu
km; the largest
tributaries – Agapa,
Yangoda and Dudypta
flow into Pyasina in
the upper and middle
stream sections) and
Nizhnyaya Taimyra
(length –
187 km,
basin area – 124 000
sq km, average
velocity – 1200-1300
cu m/sec, stream
flow – 35.2 cu km;
the largest
tributaries – the
Shrenk and
Trautfetter rivers).
A large number of
rivers flow directly
into the
Pyasinsky
Bay (Uboinaya, Morzhovaya, Beguicheva
and others) and the
south-eastern part
of the
Kara
Sea
(Lenivaya,
Khutudabiga and
others).
The majority of
large rivers have
well-structured
valleys with several
stages of flood
plains and usually
with two terraces.
The composition of
their sediments
consists mostly of
sands and sandy
loams (Pyasina,
Nizhnyaya Taimyra)
and gravel-pebble
sediments (Lenivaya,
Khutudabiga). The
vast areas of the
seashore are taken
up by delta plains
of the Pyasina and
Nizhnyaya Taimyra
rivers. Deposits of
polygonal-lode ice,
thicker than at
other sections, as
well as numerous
lakes were formed
here as a result of
a rather lengthy
period of regular
flooding. The
detailed relief
investigation in the
Pyasina delta has
shown that it was
mostly formed in the
second half of the
Holocene. Small (up
to 10 000 sq km)
lakes prevail. Lakes
on the upper and
middle flood plains
mostly have a round
shape, on the lower
– linear-elongated.
The flood plains
were subjected
during the Holocene
to an intensive
thermokarst
reworking, and up to
15% of the flood
plains` area are
taken up by drained
lake kettles.
Polygonal relief is
widespread on the
landings of the
flood plain
terraces. On the
upper flood plain
and on the first
terrace it is in the
stage of
destruction.
Ice drift and high
water on the rivers
occur in June,
freezing-over – in
September. Small
rivers are noted for
short-term level
rises, connected
with intensive
precipitation. The
estuary widths of
the Pyasina and
Nizhnaya Taimyra
rivers reach several
kilometers, the
depth – to 35-40
m
in some pits, which
apparently are of
the thermokarst
origin.
The lakes in the
northern part of
Taimyr are not
sufficiently
studied. There is
absolutely no
information about
the majority of
them; the depths are
known only in those
water bodies, which
are used for
fishing. Lakes in
the mountainous part
of the
Peninsula
are not frequent,
mostly in some deep
(several tens of
meters) kettles with
steep (15-20
degrees) slopes.
Their formation
could be connected
with the local
conditions of the
latest glacier
retreat – the
melting of the
“dead” ice massifs,
remaining in the
mountainous kettles
of the tectonic
origin.
Small water
reservoirs appeared
in the Late Holocene
in lower parts of
the relief in the
sections of thin
polygonal-lode ice`s
melting. Small (up
to
1 km
across) bottoms of
drained lakes can be
found infrequently.
On the Arctic
Institute Islands
lakes are mostly
associated with the
superface of the 1st
marine terrace with
the height of 4-7
m,
the values of the
waterline`s absolute
height not exceeding
1 m.
Two lakes are
located on the
bottom of the swampy
khasyrey. If the
archipelago`s relief
is much dissected,
the formation of
water reservoirs on
sandy interfluves is
practically
impossible. Five
lakes on the
Voronina
Island
are located on the
superface of the
modern marine
terrace. Three lakes
are formed by
temporary water
flows dammed by a
beach barrier. The
larger water
reservoir is located
in the southern part
of the island; it is
separated from the
sea by 50 –
400 m
wide sand bars and
is connected with it
by at least two
channels.
Some single water
reservoirs up to
100 m
across can be found
in the central part
of the
Izvestiy
TSIK Islands.
Along the southern
coast of the
Troinoy
Island there are several
lakes of the
residual-marine
origin (Dlinnoye,
Uglovatoye, Sredneye
and Utinoye) with
the depth up to
7 m,
separated from the
sea by pebble bars.
In the year of high
ice coverage some of
them (Dlinnoye) were
connected with the
sea by deep channels
with a rapid current
from the lake to the
sea. Becoming
gradually shallower
the water reservoirs
of such type get
completely isolated
from the sea (Uglovatoye
Lake),
as the pebble bars
widen. Small shallow
lakes are also
located at the brook
sources. Their
existence is
ephemeral and is
exclusively
connected with the
snow-melting period.
On two large islands
of the Serguey Kirov
Archipelago, in
particular on the
Slozhny
Island, there are 14 lakes, 3 of which
are in the estuaries
of temporary water
flows, and on the
Isachenko
Island
there are 8 lakes,
all the lakes lying
on the sand
superfaces of the
modern marine
terrace, directly on
the seashore, behind
beach barriers.
On the
Rastorgueva
Island (Pyasinsky
Bay)
there are two large
lakes, along with
numerous smaller
water reservoirs,
which are located on
turfed sections in
the central part of
the island.
There are few lakes
on the
Russkiy
Island.
They are mostly
pools with the
diameter up to
10 m
and the depth up to
0.5 m;
shallow water
reservoirs with
constantly changing
coastal lines and
mossy bottoms are
widespread in the
bottoms of hollows.
There are lakes with
the diameter up to
60 m,
overgrown with moss
and sedge, in two
isolated kettles
with strongly
humidified bottoms
in the centre of the
island. We can
presume that these
isolated kettles of
an almost regular
isometric shape are
the bottoms of dried
lakes. The area of
the residual lakes
in the kettles`
bottoms increases
considerably in the
period of snow
melting. The
Gusinoye Lake and
several smaller
water reservoirs on
the island`s eastern
coast are typical
residual-marine
lakes. In the cold
1992 year they were
connected with the
sea, in the warmer
1993 – separated
from it by 5 –
50 m
wide pebble bars.
These formations are
ephemeral as lakes.
Few residual-marine
lakes on the
Sverdrup
Island
are located on the
superface of a
2.5 m
high modern marine
terrace in the
immediate vicinity
of the sea and near
the rear suture of
the terrace. Small
islands can
extremely rarely be
found on strongly
rugged interfluves
of the island, where
thin polygonal-lode
ice is widespread.
The melting of this
ice at some time in
the past could lead
to the formation of
small recesses,
where atmospheric
water accumulated.
The large
residual-marine
lake
Medvezhiye is located on the southern
coast of the
Uedineniya
Island. The majority of
the other lakes is
located on the
surface of the 0.5 –
2.5 m
high modern marine
terrace built up by
sands. Except
Medvezhiye, the
coastal lines of all
other water
reservoirs change
due to the wave
activity and the
exaration of the ice
floes washed onto
the coast. Two small
lakes, the larger
having the length of
80 m
and the width of
40 m,
were used by the
first winterers for
water supply (Makkaveyev,
1957). In wintertime
they froze to the
bottom.
Some islands are
completely deprived
of water reservoirs.
One of them, for
example, is the
Morzhovy
Island in the
Pyasinsky
Bay,
which is a
80.2 m
high intrusive
massif with steep
slopes, which have
no conditions for
lake formation. A
lot of islands of
the Nordensheld
Archipelago are only
covered with placers
of rocks (Pedashenko,
Bianki, Matros and
others). However, as
soon as the
conditions for water
stay are created,
primary small lakes
and pools with the
depth to
0.5 m
and the length up to
25 m
immediately form
there (Pravda
Island). They dry
out in dry years and
appear again in
rainy years.
The majority of the
lakes on the islands
of the
Kara
Sea
are formed as a
result of the sea
lagoons` being
separated from the
sea. Their mode is
completely
determined by the
hydrogeological and
ice modes of the
surrounding water
area. Small primary
thermokarst water
bodies can be found
also in the
interfluves. They do
not exist for a long
time, since they get
quickly overgrown
with vegetation or
drained.
Soils
Primitive skeletal
soils (with a large
amount of
large-fragmented
materials) prevail
on the territory of
the Great Arctic
Nature Reserve.
Sections with
medallion
micro-relief – spots
of open ground,
separated by narrow
vegetative borders –
are widespread on
the seashore and the
islands. In the
medallion spots one
can single out humus
gleyey soils and
tundra eluvial
low-humus soils
(Atlas of the
Arctic, 1985).
Primitive detritus
and humus-detritus
soils prevail in the
mountains.
Considerable areas,
both on the
Continent and on the
islands, are taken
up by stone placers
– chaotic
accumulations of
sharp-angled blocks
up to 2-3
m
across, and are
practically deprived
of the vegetative
cover. A peculiar
hillocky-hummocky
cellular
micro-relief is
formed on the
islands built up by
sandy sediments,
blown out by the
wind, for example on
the
Sverdrup
Island. |
