Deep structure and geodynamics of the euro-arctic region
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| Опубліковано в: : | Геофизический журнал |
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| Дата: | 2010 |
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| Формат: | Стаття |
| Мова: | English |
| Опубліковано: |
Інститут геофізики ім. С.I. Субботіна НАН України
2010
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| Онлайн доступ: | https://nasplib.isofts.kiev.ua/handle/123456789/103078 |
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Deep structure and geodynamics of the euro-arctic region / N. Sharov // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 145-146. — Бібліогр.: 1 назв. — англ. |
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Sharov, N. 2016-06-13T15:42:08Z 2016-06-13T15:42:08Z 2010 Deep structure and geodynamics of the euro-arctic region / N. Sharov // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 145-146. — Бібліогр.: 1 назв. — англ. 0203-3100 https://nasplib.isofts.kiev.ua/handle/123456789/103078 en Інститут геофізики ім. С.I. Субботіна НАН України Геофизический журнал Deep structure and geodynamics of the euro-arctic region Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
| title |
Deep structure and geodynamics of the euro-arctic region |
| spellingShingle |
Deep structure and geodynamics of the euro-arctic region Sharov, N. |
| title_short |
Deep structure and geodynamics of the euro-arctic region |
| title_full |
Deep structure and geodynamics of the euro-arctic region |
| title_fullStr |
Deep structure and geodynamics of the euro-arctic region |
| title_full_unstemmed |
Deep structure and geodynamics of the euro-arctic region |
| title_sort |
deep structure and geodynamics of the euro-arctic region |
| author |
Sharov, N. |
| author_facet |
Sharov, N. |
| publishDate |
2010 |
| language |
English |
| container_title |
Геофизический журнал |
| publisher |
Інститут геофізики ім. С.I. Субботіна НАН України |
| format |
Article |
| issn |
0203-3100 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/103078 |
| citation_txt |
Deep structure and geodynamics of the euro-arctic region / N. Sharov // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 145-146. — Бібліогр.: 1 назв. — англ. |
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AT sharovn deepstructureandgeodynamicsoftheeuroarcticregion |
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2025-11-24T02:13:30Z |
| last_indexed |
2025-11-24T02:13:30Z |
| _version_ |
1850837879350099968 |
| fulltext |
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Deep structure and geodynamics of the euro-arctic region
N. Sharov, 2010
Institute of Geology, Karelian Res. Centre, RAS, Petrozavodsk, Russia
sharov@krc.karelia.ru
The Euro-Arctic region includes the Barents
Plate, the northern Baltic Shield, the northern Ti-
man-Pechera Plate and the northeastern Russian
Plate. In the west, the study region is bounded by
the Svalbard Archipelago, in the east by the Novaya
Zemlya Archipelago and in the north extends as far
as the latitude of the Franz Josef Land Archipelago.
In the region, the Kola Superdeep Borehole was
drilled to a depth of 12 km and over 450 000 linear
kilometres of seismic profiles were worked out, about
1/3 of which as a part of regional studies. Deep ho-
rizons were mapped, two- and three-dimensional
models of geological structures were developed and
deep faults were traced using the seismic method
[Lithospheric …, 2005]. Seismic data provided a
basis for interpretation by other geophysical me-
thods.
The basic characteristics of the lithospheric struc-
ture in the domain of transition from the passive
continental margin to the oceanic depression were
revealed by integrated interpretation of the data that
show the main pattern of the deep structure of the
Euro-Arctic region at its different levels. The conti-
nental parts of the platforms have an average crus-
tal thickness of 40—50 km, the upper and lower
crustal storeys having a commensurate thickness.
The plasticity level is at a depth of 20—25 km, and
usually corresponds to the lower crust surface.
Upper crust heterogeneities are compensated by
the mantle, in which either one layer with a velocity
of about 8.0—8.2 km/s or two complementary lay-
ers with velocities of 8.0—8.1 and 8.4 km/s are dis-
tinguished above the compensation level. Locally,
in palaeosuture zones the layering of the substrate
increases, and lenses with velocities of 7.6 km/s or
over 8.5 km/s appear in it. The consolidated crust
of the shelf is as thin as 15—25 km, in contrast to
oceans, where the maximum thickness of the con-
solidated crust is not more than10 km. Another cha-
racteristic of the shelf plate is a greater contribution
of the lower ("basaltic") layer to the consolidated
crust column up to the almost complete disappea-
rance of the upper crustal ("granitic") layer.
Available technical facilities and marine and
ground monitoring methods were used to form a
system of hodographs of refracted and deep reflec-
ted waves to examine the wave field structure over
a wide distance range and to study in detail the
geological structure of the earth crust and the up-
per mantle in the transition zone between the Baltic
Sea and the Barents Sea depression. At the Baltic
Shield-Barents Plate jointing the basement plunges
in stepwise manner. The sedimentary cover increas-
es in thickness to 15—20 km, and crustal thickness
decreases to 28—30 km. A layer with a velocity of
7.0 km/s was revealed in the thickest sedimentary
cover zone in the crystalline basement of the plate. A
lower-crustal layer with a velocity of 7.0—7.4 km/s was
detected locally on the Baltic Shield in rifting zones.
Therefore, its crust-mantle mixture, formed in tectono-
magmatic activation zones, can be interpreted.
New seismological data on the deep structure of
the eastern Baltic Shield have confirmed the cor-
rectness of the reconstruction of the deep structure
in which the earth crust of the modern continent
and shelf was chiefly formed in Archaean time, and
Proterozoic structural facies complexes played a
minor role. The structure of large Precambrian crustal
blocks has largely preserved to the present time,
and has only been modified in tectono-magmatic
activation zones of limited size.
Geological-geophysical interpretation of seismic
data on the Euro-Arctic region has revealed quite a
number of discrepancies in geohistorical models and
palaeoreconstructions, showing again that tectonics
and geodynamics are now at a crucial stage: sci-
entists search for a new paradigm to fit "plate-tec-
tonic" and "oscillation" concepts into a general-pur-
pose scheme.
In one group of models emphasis is placed on
the stability of continental lithospheric blocks over
billions of years, which does not prevent the perma-
nent manifestation of high-amplitude intracontinen-
tal movements in aulacogens and "isolated depres-
sions" without transformation of the continental crust
into oceanic. This group of models is based on con-
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ventional methods for interpretation of geological and
geophysical data and is consistent with the con-
cepts of an essential contribution of raid tectonics
to the platform history developed in the past few
years. In an alternative model of the destructive-ac-
cretionary history of the Barents-Pechera basin crust
a distinctive methodology, used to reveal an old
oceanic-type spreading belt buried at great depth
under a young plate cover, is especially valuable. If
these bold geophysical palaeoreconstructions are
supported by geochemical and petrological data,
then an integrated geological-geophysical metho-
dology of analysis of the evolution of continents will
be at a new, advanced level.
Lithospheric structure of the Russian part of the
Barents region / Eds. N. V. Sharov, F. P. Mitro-
References
fanov, M. L. Verba, C. Gillen — Petrozavodsk:
Karelian Res. Centre, RAS, 2005. — 318 p.
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