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Gold mining in
Chukotka from 1993 to 2004
The specific weight of the gold mining has always been playing one of
the main roles in the economy of the Chukotsky Autonomous Okrug. The
part of gold mining in the regional industry is about 44%.
Starting from the year 1992 and up to the year 2001 the annual total
amount of the recovered gold decreased from 15 tons to 5 tons. This
trend can be explained by such factors as poor social and economic
situation and reformation of the gold mining branch of the industry, as
well as this, such factors as primary mineral resources attenuation and
gold fields exploitation unfitness were also influential. Since the
year 2002 the value of the gold mining is kept on the level 4,4 – 4,9 a
year. It is important to notice that the value of the lode gold mining
is increasing mainly due to the Valounistoye and Dvoynoye mines
exploitation.
Gold mining in Chukotka from 1993 to 2004^
year 1993 1994
1995 1996 1997
1998
kg 13082,5 12489,6
9025,4 9237,6
9121,2 6071,4
year 1999 2000
2001 2002 2003
2004
kg 5107,7 6459,9
6408,8 4828,7
4668,3 4456,0
As analysis of the branch condition shows, stream-gold mining can be
done only by comparatively large enterprises with sufficient balance
funds. It was reported that by January 1, 2005 there were 156 acting
gold reconnaissance/mining licenses handed out on the territory of the
Chukotsky Autonomous Okrug (mostly in the stream-gold fields with
insignificant resources (average value – 300kg).
There are some possibilities and good preconditions for increasing the
level of precious metals mining in the Chukotsky Autonomous Okrug.
First of all, it is the presence of the lode gold fields. The
government of the Chukotsky Autonomous Okrug pays great attention to
the lode gold mining. In the last two years several investors were
found for the developing of two large fields: goldsulphide mine
Mayskoye and goldsilver mine Koupol, the exploitation of which is
considered by the government of the Chukotsky Autonomous Okrug to be
the main reason for the gold mining level increase.
On the territory of Mayskoye – one of the richest mines in Russia – the
development is performed by the Public Company «Gold Mineral
Company «Mayskoye», the affiliate of the structure Highland
Gold Mining. On the territory of Koupol mine, which can be classed
among the world-wide known facilities, the development is performed by
the joint Russia-Canada enterprise Closed Corporation «Chukotka
Geologic Mining Company». 25% of the company is a state property,
and 75% belongs to the Canadian Enterprise Bema Gold Corp. The license
possessors are already finishing preparing the technical and economical
foundation, and then the construction of the gold-extract plant is
going to start. It is planned to actuate the plants in 2007-2008.
The nearest outlooks for increasing the level of gold mining in the
region are also connected with the pickup in mining on the territories
of the acting mines «Valounistoye» and
«Karalveyem». On the whole, on the territories of the said
mines the level of mining (including the stream objects) may be
increased up to 30 tons.
Estimated volume of mining:
Characteristics 2005 2006
2007
Gold mining - total, tons 5-5.3
5,3-7,8 9,8-15,3
Silver mining - total, tons 7,2-10
10-30 30-52
The lode gold reserve fund is connected with the reconnaissance and
development of the new fields and forts on the territory of the
volcanogenic belt «Okhotsko-Chukotsky» (Central and
Southern Chukotka). Nowadays there are 6 ledges for geological
development on subsoil users’ account. All the ledges are profitable,
especially those which are situated in the area of Koupol, Valounistoye
and Mayskoye mines.
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Paleogeography And
Basin Development In The Circum-Arctic Region: Single-Grain U-Pb Dating
Of Detrital Zircon Populations From Triassic Sandstones In Ne Russia
And Comparison To Alaska And Canada
2004 Denver Annual Meeting (November 7–10, 2004) Paper No.
6-2 Presentation Time: 8:15 AM-8:30 AM
MILLER, Elizabeth, Geological and Environmental Sciences, Stanford
Univ, Stanford, CA 94305-2115, miller@pangea.stanford.edu, GEHRELS,
George, Geosciences, Univ of Arizona, Tucson, AZ 85721, AMATO, Jeffrey,
Geological Sciences, New Mexico State Univ, MSC 3AB, PO Box 30001, Las
Cruces, NM 88003, TORO, Jaime, Depart. of Geology & Geography, West
Virginia Univ, 425 White Hall, Morgantown, WV 26506, PROKOPIEV, Andrei,
Diamond and Precious Metal Geology Institute, Russian Academy of
Sciences, 39 Lenin Avenue, Yakutsk, 677891, Russia, MOORE, Thomas E.,
U.S. Geol. Survey, MS 901, 345 Middlefield Rd, Menlo Park, CA 94025,
GRANTZ, Arthur, US Geol Survey, 345 Middlefield Rd, Menlo Park, CA
94025-3561, and EMBRY, Ashton, Geol Survey of Canada, 3303 - 33rd
Street N.W, Calgary, AB T2L 2A7, Canada In order to test and explore
alternatives to existing models for the formation of the Amerasian
Basin of the Arctic, detrital zircon suites from 12 samples of Triassic
sandstone from the Circum Arctic region (100 grains each) were dated by
LA-ICPMS.
The Triassic represents the last major phase of deposition in the
Arctic region prior to the onset of Jurassic deformation and the
beginning of Cretaceous rifting and sea-floor spreading which formed
the Amerasian Basin and disrupted the original paleogeography of the
region. The samples dated provide key evidence for the reconstruction
of continental fragments dispersed during this rifting.
Samples from the Verkhoyansk thrust belt of Eastern Siberia are
characterized by strong Permo-Carboniferous (280-320 Ma), and
Cambro-Ordovician (439-540 Ma) peaks in the cumulative probability
plots. These match ages of granitoid batholiths in the Baikal Mountains
along the southern edge of the North Asia craton, and suggest that the
immense Carboniferous-Jurassic passive margin sedimentary prism of the
Verkhoyansk margin was sourced from the Baikal region with sediments
transported by a major river system flowing along the Vilyui rift
graben.
Samples from Chukotka, NE Arctic Russia, also show Permo-Carboniferous
peaks, as well as younger Permo-Triassic peaks (about 250 Ma). The
younger zircons could be derived from silicic magmas erupted during the
outpouring of basalt related to Siberian Trap LIP volcanism. Triassic
sandstones from Wrangel Island and westernmost Alaska (Lisburne Hills)
share both of these zircon age peaks. Samples from further east in
Alaska and Canada (Saddlerochit Mountains and Sverdrup Basin) do not.
The current most popular reconstruction of the Arctic Amerasian Basin
involves counter-clockwise rotation of Arctic Alaska and Chukotka away
from the Canadian Arctic margin. Although this satisfies many
constraints for the Alaska portion of the reconstruction, it places
Chukotka a great distance away from Siberia, with which is more clearly
linked depositionally based on both stratigraphic and detrital zircon
data. This discrepancy supports alternative models that involve
right-lateral slip of Chukotka from the northern Verkhoyansk along the
South Anyui suture and a more complex model for the internal
deformation of this part of the Arctic Alaska-Chukotka
microplate.
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Research in Chukotka, Russia
Scientists wishing to conduct scientific research in Chukotka (Russia)
are now able to call upon BASC for logistical support and for
assistance with obtaining all necessary local, regional and federal
(Russian) permits for their projects. With the active support of
Chukotka’s new Governor, the Honorable Roman Abramovich, and in
conjunction with the Chukotka Science Support Group (CSSG), BASC is
beginning to offer "one stop shopping" for science support in the
Chukotka Autonomous Okrug (equivalent to a state in the U.S.).
CSSG has been formed by two Chukotka-based Native organizations that
have provided logistical support to science projects in Chukotka for
the past decade. These organizations are the Naukan Production
Cooperative (headquarters in Lavrentiya) and the Yupik Eskimo Society
(headquarters in Provideniya). CSSG has been formed to work directly
with BASC in support of scientific projects in Chukotka. CSSG is funded
through BASC's Cooperative Agreement with the National Science
Foundation's Office of Polar Programs.
BASC and CSSG are currently facilitating several NSF projects in
Chukotka as well as a National Oceanic and Atmospheric Administration
(NOAA) research project and an Environmental Protection Agency
education project. In 2001, BASC's Executive Director, Glenn W.
Sheehan, toured CSSG facilities in Provideniya and Lavrentiya. While in
Russia, Dr. Sheehan met with Chukotka Governor Roman Abramovich to
discuss planned science activities in Chukotka.
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Volcanism and Exhumation of
Okhotsk-Chukotka
Arc Revealed by Detrital Fission-Track Ages of Zircon from the
Ukelayet Flysch, Kamchatka
Garver, J.I. * Department of Geology, Olin Center, Union College,
Schenectady, New York, USA,
Brandon, M.T. Geology and Geophysics, Yale University, New Haven,
Connecticut, USA
Soloviev, A.V., Inst. of the Lithosphere, RAS, Staromonetny per.
22, Moscow, Russia, 109180
Bullen, M.E. Department of Geology, Olin Center, Union College,
Schenectady,
New York, USA, (now at: Exxon, New Orleans, LA)
The Ukelayet Flysch represents forearc strata to the Okhotsk-Chukotka
continental arc build on the Eurasian mainland in the NW Pacific in the
Cretaceous to Early Tertiary.
The flysch belt is a 10-to-15-km-thick zone of deformed turbidites that
rest in the footwall to the Olutorsky collision zone. Fission-track
(FT) dating of detrital zircon from sandstones constrain the timing of
flysch deposition and exhumation of the source which was a continental
arc to the west.
The young populations of fission-track grain ages (P1) defines a FT
depositional age, which is the maximum age of unit.
Because all sandstones have colorless, euhedral zircons, ascribed to
active volcanism in the source, we infer that the FT depositional age
is close to the time of actual deposition.
FT depositional ages from 27 samples range from 88
(Cenomanian-Campanian) to 44 Ma (Middle Eocene), suggesting over 40 Myr
of continuous deposition as the FT peak ages are distributed throughout
this entire interval.
The nine youngest samples are Middle Eocene in age suggesting collision
and overthrusting of the Olutorsky terrane on the Vatyna thrust must
have occurred during or after this time.
In fact, these young FTGA results may actually date the timing of
collision because the flysch in the two areas where we obtained Middle
Eocene ages, is marked by local but significant occurrences of
olistostromes interpreted to be derived from upper plate rocks.
A second population (P2) of grain ages, represents progressive
exhumation of the basement to the Okhotsk-Chukotka Arc.
When compared to FT depositional age, P2 gets younger with time
suggesting progressive exhumation over 50 Myr at rates of ~120-400
m/Myr. This exhumation was maintained from ~90 to 44 Ma and it resulted
in the erosional removal of about 9 to 18 km of crustal material.
The change in exhumation rates at ~70 Ma may represent the shift in the
locus of volcanism from the Okhotsk-Chukotka Arc eastward.
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Tectonics of NE
Russia: Pivotal issues and uncertainties
Geological Institute, Pyzhevsky 7, Moscow, 119017 Russian Federation
The main feature of the tectonic setup of NE Russia is the existence
there of two contrasting tectonic grains: (1) Verkhoyansk-Chukotka
orogenic belt (VCOB) with a markedly mosaic tectonic style and
predominance of NW trends modified by the "Kolyma loop," and
(2) Koryak-Kamchatka orogenic belt (KKOB), with its typical NE-trending
linear features, conformable to the general tectonic grain of the
Circum-Pacific foldbelts.
Such sharp contrast in the tectonic grain can be explained as follows:
(i) evolution of the VCOB was dominated by collisional processes,
whereas, the KKOA provided the stage for accretionary ones;
(ii) the VCOB incorporates terranes with continental crust
(microcontinents);
(iii) the paleostructures of the VCOB were separated from the Pacific
by a convergent boundary, and their origin was not therefore related to
the motions of Pacific plates-as was the case with the terranes of the
KKOA.
The time of inception of the convergent boundary between Eurasia and NW
Pacific remains poorly constrained.
Reliable reconstructions become feasible starting only from as late as
the Late Jurassic.
There are two different approaches on the origin and evolution of South
Anyui suture (SAS):
(1) Late Mesozoic rift; and
(2) remnant after the closure of a Pacific re-entrant.
The multiplicity of the viewpoints is due to the insufficient knowledge
of the region and, primarily, to the lack of reliable data on (i) the
structures of the different segments of the SAS and its northern and
southern surroundings; (ii) age of the oceanic fragments; (iii) the
tectonic position and geodynamic settings of the ophiolites; (iv)
timing of the principal geologic events such as metamorphism,
island-arc volcanism, granite emplacement, collision, etc.; (v)
depositional environments and clastic sources of the Triassic -Early
Cretaceous sediments.
These white spots in our knowledge of the tectonic setup of the
Chukotka Peninsula prevent us from adopting or rejecting the popular
tectonic model viewing Chukotka as a microplate that split off Canada's
Arctic margin to eventually dock onto the North Asian continent.
In the KKOA, the pivotal issue is the original location of terranes,
their travel paths, and the timing and mode of their accretion.
This applies to the following terranes: (i) Ganychalan, including Early
Paleozoic ophiolites that have no counterparts anywhere in NE Asia and
that are likely fragments of oceanic lithosphere of the Pacific,
Iapetus, or the Paleo-Asian Ocean; and (ii) the terranes carrying Late
Paleozoic limestones and Tethyan faunas. Such units are common within
the northern Circum-Pacific accretionary complexes (Cache Creek terrane
in British Columbia, Akieshi terrane in Japan, etc.), and they are
critical to paleotectonic reconstructions; and (iii) the numerous and
diverse island arc terranes with both Tethyan and boreal faunas. It
should be investigated which island arc terranes provided convergent
boundaries to which plates, and by which Pacific plates these terranes
were transported. Supported by the Russian Foundation for Basic
Research (project 02-05-64217).
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Phanerozoic Tectonic
Evolution of the Chukotka-Arctic Alaska Block:
Problems of the Rotational Model
* Natal'in, B A (natalin@itu.edu.tr) , Istanbul Technical University,
Faculty of Mines, Ayazaga, Istanbul, 34469 Turkey
Correlation of tectonostratigraphic units across the Bering Strait
suggests that the northern Chukotka including most of the East Siberian
Shelf as well as the Brooks Range, Colville Basin, Beaufort Shelf, and
Seward Peninsula on the North American side represent a large
continental block.
The core of this block consists of the Neoproterozoic Bennett-Barrovia
block (BBB) that is overlain by the Ordovician-Devonian Novosibirsk
carbonate platform.
The basement of the block is exposed in the Chukotka Peninsula where
orthogneiss yielded Late Proterozoic (650 to 550 Ma) U-Pb ages. These
dates are comparable with the age of 699 Ma reported for granites in
the Wrangel island. Granites of the same age intrude metasedimentary
and metavolcanic rocks in the Hammond subterrane in northern Alaska.
In the western part of the BBB, geophysical data imply a presence of a
crystalline Precambrian basement at shallow depth beneath the
Novosibirsk Archipelago. Weak deformation and consistency of facies of
Ordovician-Devonian shelf and lagoon carbonates indicate that the BBB
evolved as a rigid structure. A similarity of the Ordovician fossils
with Siberia allows an inference about a close location of these two
continental entities.
The BBB forms a backbone of the Chukotka-Alaska block. Since the
early Paleozoic, it started to grow at the expense of
subduction-accretion.
Ordovician and Silurian oceanic and island arc rocks mark the northern
boundary of the BBB. This subduction boundary stopped its development
after the late Silurian-early Devonian collision of the BBB and the
North America craton. Subduction along the southern boundary of the BBB
is recorded by a Devonian-early Carboniferous magmatic arc (granites
yielding 360-398 Ma) and an extensional (backarc) basin. Perhaps, this
subduction was terminated by a middle Carboniferous collision.
The Triassic extension along the same boundary caused formation of the
South Anyui ocean and a wide passive continental margin exposed in the
northern Chukotka.
The early Cretaceous closure of the ocean was followed by longitudinal
shortening of the Chukotka-Arctic Alaska block as it is evident from
orogen-parallel strike-slip faults and oroclinal bending of structural
trends.
The Bering Sea orocline accounts for almost double shortening of the
original length of the Chukotka-Arctic Alaska block between the
Chukotka and Seaward peninsulas. This shortening caused thickening of
the crust and its extensional collapse that led to exhumation of
metamorphic complexes.
The reviewed tectonic structure and history impose constrains on
geometry of the Chukotka-Arctic Alaska block. In many tectonic models,
its counterclockwise rotation because of the opening of the Canada
Basin and the following collision with the mainland of Asia is
considered as the primary mechanism of the Cretaceous orogeny.
However, the present day length of the BBB stretching from the
Alaska-Canada border in the east to the Novosibirsk Archipelago in the
west contradicts to this simple scenario. The original length of the
BBB must be longer if the Cretaceous longitudinal shortening is
restored. To overcome the space problem it is suggested that in the
late Mesozoic the BBB moved right laterally along the North American
margin and that the opening of the Canada Basin is a consequence of
this giant strike-slip motion.
GP43C-05 14:40h
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Geology of Chukotka, Kolyma
and northern Yakutia
K: Koni Mugal volcanic belt; OB: Okhotsk block; OCVB: Okhotsk-Chukotka
Volcanic belt; SA: Southern Anui Suture zone Schematic tectonics of the
Magadan-Chukotka area.
Northeast Russia in a geological sense is located east of the Siberian
Craton. Politically it comprises the northeastern part of Yakutia,
Magadan Obast and Chukotka. The tectonic history of the area is rather
complex and not yet fully understood. The main geological units in the
area today are the following:
Verkhoyansk fold belt The Verkhoyansk fold belt is located in eastern
Yakutia and part of the Magadan oblast. It is situated between the
Siberian craton in the west and the Kolyma-Omolon superterrane. The
Verkhoyansk fold belt is composed of sediments, deposited along the
margins of the Siberian craton. It's age is Mississipian to early
cretaceous.
Kolyma-Omolon Superterrane This unit is situated in the central to
northern part of the Magadan oblast. The Kolyma-Omolon superterrane is
a jigsaw of several microcontinantal fragments, called blocks.
Examples of such blocks are the Omolon block in the southeast and the
Prikolyma block just west of the Omolon block, while the Omuliovka
block is located more to the southwest. All these blocks are covered by
paleozoic to cretaceous sediments. The individual blocks are separated
by late Paleozoic to Mesozoic fault and shear zones.
Chukotka terrane The Chukotka terrane is along the northern shore of
Chukotka, inlcuding Wrangell Island.
South Anui Suture zone The South Anui suture is located between the
Kolyma-Omolon superterrane and the Chukotka terrane. In fact the South
Anui Zone is the result of classic collision of continents, as can also
be seen in the Urals. In this case the collision between the Siberian
continent and the Chukotka terrane. Before the collision there was a
rift zone.
Okhotsk-Chukotka volcanic Belt (OCVB) The OCVB is of cretaceous age.
The OCVB is situated along the northern shore of the Sea of
Okhotsk and can be followed further northeast all the way to to
area of Anadyr at the Bering Strait. The belt has a length of
about 3200km and consist of volcanic and plutonic rocks. In cretaceous
times this belt was a subduction zone. Present day Kamchatka and the
sea of Okhotsk where pushed northwards and subducted under the
exsisting terranes.
Koni-Mugal volcanic belt The Koni-Mugal volcanic belt is situated
southeast of Magadan and south of the OCVB.
Okhotsk Block The Okhotsk block is situated southeast of the
Verkhoyansk fold belt. It is only a small structure.
references
New 40Ar/39Ar ages of Cretaceous continental volcanics from Central
Chukotka: implications for initiation and duration of volcanism within
the northern part of the Okhotsk Chukotka Volcanic Belt (northeastern
Russia), by V.O. Ispolatov et al, Journal of Geology, october 2003.
South Anyui suture, northeast Arctic Russia:Facts and problems, by S.D.
Sokolov et al, Geological Soc. of America Special Paper 360, 2002,
pp209-224 StatCounter - Free Web Tracker and Counter
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Sibneft Begins
Offshore Seismic Work in Chukotka's Anadyr Bay
Sibneft 7/19/2005
URL: http://www.rigzone.com/news/article.asp?a_id=23900
Sibneft has begun carrying out geophysical exploration work on the
Tumanskiy license block, located in the Anadyr Bay section of the
Bering Sea. The company plans to collect 3000 kilometers of seismic
data at the site. The data will shed light on the geology of subsurface
structures previously determined to be promising, thereby helping to
design a program of exploration drilling on the field for 2006.
Sibneft-Chukotka received a five-year geological exploration license
for the Tumanskiy block in November 2003. The block covers about 13,000
square kilometers in water that is 25 to 60 meters in depth. There are
five localized structures within the license area, with total
geological resources estimated to exceed 1 billion tons of oil
equivalent.
Geological work likewise continues at other Sibneft license sites in
the Chukotka region. At the Telekaiskoye oil and gas condensate field,
testing is underway on a well that, in 2004, produced industrial flows
of oil. Sibneft has also built geological models of the offshore
portion of the Anadyr oil & gas basin based on drilling and seismic
work carried out in the region, identifying several more promising
structures.
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exploration
history
ARCO has signed preliminary agreements with two
local
governments covering E&P in the Soviet Far East.
ARCO's protocols with regional councils of
Magadan and
the Chukotka Autonomous Area pave the way for ARCO to negotiate for
exclusive
rights for onshore and offshore E&D. Target areas will be
identified
in subsequent negotiations. The councils will help ARCO obtain required
legal approvals of the Soviet and Russian Federation governments. |
