Ecology/6.
Ecologic monitoring
D.V. Ulrich, Cand.Sc.
(Engineering); G.O. Zhbankov, postgraduate student; S.E. Denisov, Dr.Sc.
(Engineering)
South Ural State
University, Russia
Stratigraphy and petrography of
Karabash syncline.
The
characterized region is composed of volcanic sedimentary rocks of the lower and
middle Paleozoic era metamorphosed in terms of the greenschist facies and
breached by the linear intrusions. To the west and east along regional tectonic
dislocation greenstone bodies come into contact with highly metamorphosed rock
units of Uraltauskiy and Ilmenskiy solid masses correspondingly. The above
mentioned units are partially eluviated and overlapped by thin sedimentary
cover of blanket quaternary deposits of various genesis and composition.
Upper
volcanic sedimentary formation (S1 ln-w): deposits with the name of
upper volcanic sedimentary formation crop out to the day in the central part of
Karabash syncline, the region where they build up western roots of Sidorkiniy
mountains, western slopes of Berezovskiy and Konniy ridges; and can be visible
along eastern slopes of Lysaya, Zolotaya and Karabash mountains to the south
beyond the characterized area.
There
is no a complete uninterrupted section of formation within this area.
The
composition of the characterized formation consist of three steeply pitching to
the east benches (65º - 80º), they are lower volcanogenic (traprocks,
porphyrite and calc sinters with interbedded tuff sandstone); middle sandstone
(tufaceous sandstones of mafic composition with siliceous tuffites interbedded
at the base, rarely of a mixed composition with quartzite shale rocks
interbedded at the top); and upper schist ones (phyllitic clayed, topsoil and
quartzite schists).
There
are mutual transitions between these benches. Visible thickness of formation is
800-1000 meters.
Sedimentary
volcanogenic formation (S2ld-D1c): It is composed with
deposits united in the stratum and developed within Miassko-Sugomakskiy and
Saimonovo-Sharabrinskiy blocks.
In
terms of lithological composition the formation can be divided into two
sub-formations, they are the lower (sedimentary) and the upper (volcanogenic)
ones.
Lower
(sedimentary) sub-formation represents conformable clayed, sandy clayed and
quartzite schists and tufaceous and shaly sandstones. We can observe relatively
thin interbedded small-grained crystalline limestone (10-15 m) and rarely
pyroxene porphyrites. The thickness of a sub-formation is 300-350 m.
Upper
(volcanogenic) sub-formation is much more popular and represents pyroxene,
plagioclase and pyroxene, basaltic, andesite-basaltic porphyrites and their
sinters. In a sub-formation thin interbedded tufaceous sandstones are
developed.
Middle
volcanogenic formation (D1c-D2e): the formation is
composed of a great number of rocks. It has the following stones metamorphosed
to a variable degree: they are traprocks, diabase porphyrites, and their
sinters and tufaceous sandstones. There are heavy lenses of marmorized
limestones (up to 250 m) in separate blocks of the formation. The thickness of
formation is unfixed and is increasing from north to south.
Upper
volcanogenic formation (D2å-gv): the composition of
rocks built up the formation is of a variable and unbalanced character: there
are felsic and mafic porphyrites and sinters, alteration of clay shale, carbon
siliceous, quartz sericite and other schists; tufaceous sandstones; rarely banded
iron formations. In the area of Karabash town in the lower part of the section
at volcanogenic formation bedding there are siliceous, carbon and siliceous,
clay shale rocks and tuffites. In the middle part of the formation a heavy unit
of marmoized limestones (up to 300 m) is logged.
Intrusive
rocks: intrusive rocks are expanding in the characterized region. They present
a wide range of ultramafic, mafic and felsic rocks. Intrusive rocks of the
region are dated to lower Middle Devonian and Middle Upper Devonian Cycles.
Lower-Middle-Upper
Devonian Cycle: corniferous apopyroxenite rocks and grey gabbro amphibolites
dismanteled in the valley of the Olkhovka River, to the north-west of the
region in the Ufaleiskiy metamorphic aureole with greenstone units of
Tagilo-Magnitogork mountain trench belong to the cycle. From west along the
tectonic deformation they come into contact with sedimentary rocks of the
Curtin suite composed by garnet mica schists. Residuals of the schists can be
seen in the eastern aureole of pyroxenites with later gabbro intrusions (D2-3)
as well as inside the intrusions. From south gabbro pyroxenites intrusion is
outlined by gabbro serpentinites of Middle Upper Devonian era which is the
northern end of the Talovskie mountains group.
Gabbro
amphibolites are massive medium granular and slightly interstratified rocks of
a dark or dark grey color. There can be banded varieties, deformed into minor
folds and presented by interdigitation of dark bands consisting of protobase
with interbeds enriched by plagioclase.
Middle
Upper Devonian Intrusive Cycle: basic number of solid masses within described
region composed of serpentinites and intrusions which are difficult to
differentiate from pyroxenites to plagiogranites belongs to this cycle.
Intrusions
of the cycle transect the whole unit of greenstone rocks, which are dated to
from the Upper Ordovician period till the Givetian age of Middle Devonian.
In
the formation of intrusions we may identify two stages that seem to be divided
by a small period of time.
Serpentine
belts confined to the zones of deep-seated faults belong to the first intrusive stage. In the
described region from north-east to south-west Sidorkinskaya branch of
Sidorkinsko-Karabash serpentine belt, which is in its turn divided into two
chains: western and eastern ones, is traced.
The
exposure of serpentinites is not the same. They usually give rocky outcrop and heavy
block rocky debris on the top of the mountains and hills. Bed-rock outcrops
occur less frequently in the upper parts of the slopes and mountain roots where
there are usually heavy deluvial block masses of serpentinites of brown sandy
loams and sit loams.
Steady
serpentinites are green grey or blue grey, have scaly, micrograting, acicular,
sheaf-like and radial fibrous structure. The texture is cryptocrystalline,
massive, sheeted or brecciated. The processes of talc formation and
carbonization considerably confined to the west endomorphosed part of the units
are highly developed in serpentinites.
In
the south-western part of the described region there is East-Barninskiy
serpentine belt. Serpentinite building up this belt can be traced in
north-north-eastern direction from the southern end of Karabash town to the
Olkhovka River, building up Bogorodskaya, Zavodskie and Krestovaya mountains.
Maximum belt width is marked in the southern region of Bogorodskaya mountain
(up to 600 m). The belt is built up with antigorytos difference of
serpentinites carbonated and talcose of various degrees.
Apart
from characterized belts separate tiny bodies of serpentinites metamorphosed in
various degrees are recorded.
The
complex of rocks of mafic and alkali structure intruded by the intrusions of
the first stage belongs to the second stage of Middle Upper Devonian intrusion
cycle. In most cases they are restricted to the western junctions of serpentine
belts. Massive intrusive bodies of gabbro and diorites are marked in the south-western
part of the region.
Hydrothermal
metasomatic rocks: numerous manifestations of intrusive and accompanying it
hydrothermal activity have determined development of metasomatic and
hydrothermal rocks of a complex structure, among which ore-bearing shale rocks are
mainly developed.
Ore-bearing
schists (hsz-gh): Hydrothermal metasomatic units which accompany the process of
sulphide salinity belong to this group. They are basically distributed in
deposits of upper volcanogenic formation of Soimanovsko-Sharabrinskiy block (D2e-gv)
building up north-north-eastern extension zone traced from the south boarder up
to Sharabrin stream. This zone consists of echelon folding with the range of a
few to tens meters. In its majority these rocks are rudaceous and middle
fragmentary calc-sinters of a dacitic, andesite-dacitic structure and
plagiogranites. Schist formations of tufaceous sandstones of a mixed and mafic
structure are less frequent as well as the formations of traprocks and other
mafic volcanogenic rocks.
In
the expansion of described schists we can observe the following regularity.
Central parts of schistic zones are formed by quartzite serictic or quartzite
chlorite seritic schists and marginal parts are formed by quartzite chlorite
schists.
Paleozoic
deposits are considerably topped off by sedentary deposits and deposits of
Quaternary period. In terms of genesis they can be divided into alluvial,
colluvial, eluvial, diluvial and technogenic mineral formations.
Alluvial
deposits (aQ): Alluvial deposits expanding along the valley of the Miass River
and the lower course of the Sak-Elga River are composed by sandy-pebbled
material. The expansion of pebble material is incoherent. Fragmentary material
is basically quartzite one. In the mass of terrigenous material interbed of
grey clay, clay loam and fine sandy loam can be observed. Thin decayed peat bog
(up to 40 cm) of a woody-fen type can be traced in microdepression. The width
of alluvium is from 3.2 m up to 17.7 m.
Colluvial
and proluvial deposits (proQ): On the steep slope of side-hills we can see
loosened rocks and debris which are of a colluvial deposit origin. Lithological
peculiarities of colluvium are entirely determined by the structure of enduring
Paleozoic rocks. Colluvium is introduced by block masses, breakstones as well
as clay with breakstones.
Colluvial
deposits are closely connected with proluvial deposits forming cones and
alluvial piedmont plains on the mountain slopes. They are characterized by
flattened blocks of Paleozoic rocks concrete-bound by silt loams and fine sandy
loams. The width of deposits is in direct relation with land forms and is not
balanced.
Eluvial
deposits (eMz): Eluvial deposits cover smooth hillsides and flat tops. The
width of covering is different: it can be up to 1-3 m. Eluvium is usually
represented by block masses, breakstone, rotted rocks and sand-clay aggregates.
At ultrabasites the width of eluvium is insignificant which is not more than
0.5; eluvium is formed by serpentinite chips which are
partially silicified and carbonated and enclosed in brown clay mixture. Eluvium
of carbon silicious schists is of 3 m and represented by brown, yellow and
green clay with chlorite lamels and quartzite rubbles.
Deluvial
deposits (dQ): Deluvial deposits are the products of eluvium sheet flood down
the slope and are characterized by some assortment of the material. They are
represented by brown, greyish brown, brownish grey clay loams, clay with
breakstones of bedding rocks and scree quartz debris. The width of deposits is
from 0.1 up to 12 m.