Induced small-scale convection in the asthenosphere in continent-continent collision zones
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| Опубліковано в: : | Геофизический журнал |
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| Дата: | 2010 |
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| Формат: | Стаття |
| Мова: | Англійська |
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Інститут геофізики ім. С.I. Субботіна НАН України
2010
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| Назва журналу: | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| Цитувати: | Induced small-scale convection in the asthenosphere in continent-continent collision zones / E. Timoshkina, V. Mikhailov // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 184-185. — Бібліогр.: 3 назв. — англ. |
Репозитарії
Digital Library of Periodicals of National Academy of Sciences of Ukraine| _version_ | 1859970048169345024 |
|---|---|
| author | Timoshkina, E. Mikhailov, V. |
| author_facet | Timoshkina, E. Mikhailov, V. |
| citation_txt | Induced small-scale convection in the asthenosphere in continent-continent collision zones / E. Timoshkina, V. Mikhailov // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 184-185. — Бібліогр.: 3 назв. — англ. |
| collection | DSpace DC |
| container_title | Геофизический журнал |
| first_indexed | 2025-12-07T16:21:43Z |
| format | Article |
| fulltext |
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Induced small-scale convection in the asthenosphere
in continent-continent collision zones
E. Timoshkina, V. Mikhailov, 2010
Institute of Physics of the Earth, RAS, Moscow, Russia
tim@ifz.ru
mikh@ifz.ru
We investigated interaction of the lithosphere and
the asthenosphere in continent-continent collision
zone using a rheologically stratified model of the
Earth outer shell including sedimentary layer, the
lithosphere, the asthenosphere and uppermost part
of the mantle. [Mikhailov et al., 1996]. The litho-
sphere — asthenosphere boundary is a rheological
one and determined by position of specified isotherm.
Equation for the top of the model includes detailed
description of sedimentation and erosion. The model
is asymptotically matched to the model of mantle
convection what solves the problem of boundary
conditions at its lower boundary. The model per-
mits modelling of active extension and compres-
sion by mantle-induced or intraplate forces as well
as relaxation of mechanical and thermal disequilib-
rium arose at active tectonic stages.
Active tectonic deformations of the Earth’s outer
shell by external mantle-induced or intraplate forces
disturb thermal and mechanical equilibrium within
this shell. Our model demonstrates that these dis-
turbances lead to formation of small-scale convec-
tion within low-viscosity asthenosphere. This convec-
tion plays important role in restoration of thermal
and mechanical equilibrium in the Earth outer shell
and it style depends also on the surface (sedimen-
tation and erosion) processes. Small-scale con-
vection lasts over a long period of time after cessa-
tion of external tectonic forces, causing deforma-
tions in overlying lithosphere. In a continent-conti-
nent collision environment the small scale convec-
tion amplifies uplift of orogenic belts and causes
subsidence at their periphery. We consider the small
scale convection to be the main driving mechanisms
of foredeep basins formation [Mikhailov et al., 1999;
Timoshkina et al., 2010].
To illustrate this model we perform results of
detailed modelling of the Great Caucasus orogen
formation. To assign correctly initial conditions to
the beginning of compressional stage, we consid-
ered preceding stages including: 1) extension of con-
tinental lithosphere in the early Jurassic; 2) subse-
quent post-extensional subsidence; 3) compres-
sional (collisional) stage, when the system orogen
— foredeeps forms. Parameters of the lithosphere
and the asthenosphere and parameters of exten-
Distribution of temperature (gray scale), position of main boundaries in the lithosphere and sedimentary cover and small-scale
convection in the model of the Great Caucasus — North Caucasus foredeep formed in result of four compressional events
before beginning of the present-day compressional one. The right side of the symmetric figure is shown. The centre of the
orogen is at the left (x=0). The maximum length of arrows corresponds to 1.3 mm/year.
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sional — compressional processes were selected
to provide a result close to the Great Caucasus —
North Caucasus foredeeps, including topography,
deep structure, thermal regime, subsidence history,
gravity anomalies and so on.
The suggested model shows a good agreement
with the data on the foredeeps structure and evolu-
tion. In particular, it is able to explain thickness of
sediments in foredeep basins and their shape, for-
mation of foredeeps not only at the front but also at
the back of compressional thrust belts, uplift of a
foredeep during compression in the belt and rapid
subsidence after cessation of external compression.
Comparison of the numerical results with the ob-
served data on the North Caucasus foredeep permits
new interpretation of existing geological data [Timo-
shkina et al., 2010]. In particular, it is possible to con-
Mikhailov V. O., Myasnikov V. P., Timoshkina E. P. Dy-
namics of the Earth' outer shell evolution under
extension and compression // Izvestiya. Physics of
the Solid Earth. — 1996. — 32, ��6. — P. 496—502.
clude, that the system orogen — foredeep resulted
from at least five active compressional events sepa-
rated by periods of relatively weak tectonic activity.
The first compressional event took place before the
formation of the Maykopian series, i. e. 39.5 Ma, and
could be related to the closure of the Arabian Ocean
and subsequent beginning of the continent-continent
collision in the Lesser Caucasus. There is still no con-
sensus on when compression and orogeny in the
Caucasus region commenced, many researchers
estimate beginning of the compression by conside-
rably later date. The four further compressional events
can also be recognised — one of them being between
16.6 and 15.8 Ma, the others — between 14.3 and
13.7 Ma and between 7.0 and 5.2 Ma. These stages
coincide well with geological data. The present day
stage is also an active compression one.
References
Mikhailov V. O., Timoshkina E. P., Polino R. Foredeep
basins: the main features and model of forma-
tion // Tectonophysics. — 1999. — 308. —
P. 345—360.
Timoshkina E. P., Leonov Yu. G., Mikhailov V. O. For-
mation of orogen — foredeep system: geodynamic
model and its comparison to the North Caucasus
data // Geotectonics. — 2010. — ��5. — P. 1—20.
|
| id | nasplib_isofts_kiev_ua-123456789-103102 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 0203-3100 |
| language | English |
| last_indexed | 2025-12-07T16:21:43Z |
| publishDate | 2010 |
| publisher | Інститут геофізики ім. С.I. Субботіна НАН України |
| record_format | dspace |
| spelling | Timoshkina, E. Mikhailov, V. 2016-06-13T15:58:06Z 2016-06-13T15:58:06Z 2010 Induced small-scale convection in the asthenosphere in continent-continent collision zones / E. Timoshkina, V. Mikhailov // Геофизический журнал. — 2010. — Т. 32, № 4. — С. 184-185. — Бібліогр.: 3 назв. — англ. 0203-3100 https://nasplib.isofts.kiev.ua/handle/123456789/103102 en Інститут геофізики ім. С.I. Субботіна НАН України Геофизический журнал Induced small-scale convection in the asthenosphere in continent-continent collision zones Article published earlier |
| spellingShingle | Induced small-scale convection in the asthenosphere in continent-continent collision zones Timoshkina, E. Mikhailov, V. |
| title | Induced small-scale convection in the asthenosphere in continent-continent collision zones |
| title_full | Induced small-scale convection in the asthenosphere in continent-continent collision zones |
| title_fullStr | Induced small-scale convection in the asthenosphere in continent-continent collision zones |
| title_full_unstemmed | Induced small-scale convection in the asthenosphere in continent-continent collision zones |
| title_short | Induced small-scale convection in the asthenosphere in continent-continent collision zones |
| title_sort | induced small-scale convection in the asthenosphere in continent-continent collision zones |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/103102 |
| work_keys_str_mv | AT timoshkinae inducedsmallscaleconvectionintheasthenosphereincontinentcontinentcollisionzones AT mikhailovv inducedsmallscaleconvectionintheasthenosphereincontinentcontinentcollisionzones |