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O. P. Polyansky S. N. Korobeynikov V. G. Sverdlova A. V. Babichev V. V. Reverdatto 《Doklady Earth Sciences》2010,430(2):158-162
Computer simulation of subduction was performed using nonlinear equations of deformable solid mechanics encompassing all types
of nonlinearity: geometric, physical, and contact. This study presents a numerical model of subduction with allowance for
the gabbro-to-eclogite phase transition. The model rheology is a plastic compressible material (Mohr-Coulomb law for a deformed
rock material). It was shown that deep subduction can be modeled well with the selection of appropriate parameters of rock
plasticity providing the initial thickening in the subducting slab nose. 相似文献
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A. V. Babichev S. N. Korobeynikov O. P. Polyansky V. V. Reverdatto 《Doklady Earth Sciences》2014,455(1):327-330
The results of numerical mathematical modeling of rock deformations under compression are given. The numerical solutions are obtained using discretization of the equations of the solid mechanics with the finite element method. The model of an ideal elastic-plastic material with a Huber-Mises yield surface was used in the calculations. The layered medium structure is taken into account in modeling of the compression of layers of the lower/middle crust on a local scale. The natural folds in strongly deformed metamorphic sequences were reproduced by the mathematical deformation models. It is shown that folding in the lower part of the Earth’s crust is possible, when the yield stresses of the host rocks are approximately two orders of magnitude less than those of the hard layers. The effect of the boundary conditions and thickness of the compressed rocks on the folding is shown. 相似文献
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Polyansky O. P. Korobeynikov S. N. Babichev A. V. Reverdatto V. V. Sverdlova V. G. 《Doklady Earth Sciences》2009,429(1):1380-1384
A new point of view describing processes of partial melting and development of gravitational instability in a thickening crust
with increased thickness of the granite layer is suggested. Numeral experiments support the following main conclusions. The
critical volume of partially melted material should be formed for the beginning of flotation in a gravitational field. Due
to model estimations, the height of the melting area in the granite crust should be not less than 6–7 km. A mushroom-shaped
form of the floating body was observed in all models regardless of the thermal source size (fixed or variable width): the
high temperature channel (magma leader) and head body of the diapir are formed. The height of diapir floating depends on rheological
features of the surrounding crust: 10 times increase in the yield strength (from 1 to 10 MPa) while temperature decrease confines
the possible level of rising to a depth of 15–16 km. An elevation of about 750 m is formed in the day surface relief above
the axis part of the diapir. 相似文献
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Computer modeling of granite gneiss diapirism in the Earth’s crust: Controlling factors,duration, and temperature regime 总被引：1，自引：0，他引：1
This paper is devoted to the modeling the granite gneiss formation by means of diapiric upwelling. The natural examples of
granitic diapirism in the Precambrian granite-greenstone belts and complexes of metamorphic cores are described. A new approach
is proposed to describe the partial melting and development of gravity instability in the crustal granitic layer, which experienced
heat impact and melting during intrusion of basaltic melt. Rheology of partially melted material and surrounding medium is
regarded to be temperature-dependent, following either plasticity or creep (non-Newtonian viscosity) law. Modeling results
show that crustal rheology plays a significant role in the character of diapirism (shape of upwelling bodies, duration of
the process, and width of thermal aureole). The rates of upwelling within the crust behaving as elastoplastic body are orders
of magnitude higher (meters to tens meters per year) than those obtained for creep (viscous) liquid model (0.8 cm/yr). Modeling
results revealed that the limiting depth of upwelling of partially crystallized melt, with allowance for temperature dependence
of creep, corresponds to the isotherm of 400°C. 相似文献
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O.P. Polyansky A.V. Prokop'ev A.V. Babichev S.N. Korobeynikov V.V. Reverdatto 《Russian Geology and Geophysics》2013,54(2):121-137
Results of modeling of the formation of the Vilyui sedimentary basin are presented. We combine backstripping reconstructions of sedimentation and thermal regime during the subsidence with a numerical simulation based on the deformable solid mechanics. Lithological data and stratigraphic sections were used to “strip” the sedimentary beds successively and calculate the depth of the stratigraphic units during the sedimentation. It is the first time that the evolution of sedimentation which is nonuniform over the basin area has been analyzed for the Vilyui basin. The rift origin of the basin is proven. We estimate the spatial distribution of the parameters of crustal and mantle-lithosphere extension as well as expansion due to dike intrusion. According to the reconstructions, the type of subsidence curves for the sedimentary rocks of the basin depends on the tectonic regime of sedimentation in individual basins. The backstripping analysis revealed two stages of extension (sediments 4–5 km thick) and a foreland stage (sediments > 2 km thick). With the two-layered lithosphere model, we conclude that the subcrustal layer underwent predominant extension (by a factor of 1.2–2.0 vs. 1.1–1.4 in the crust). The goal of numerical experiments is to demonstrate that deep troughs can form in the continental crust under its finite extension. Unlike the oceanic rifting models, this modeling shows no complete destruction or rupture of the continental crust during the extension. The 2D numerical simulation shows the possibility of considerable basement subsidence near the central axis and explains why mafic dikes are concentrated on the basin periphery. 相似文献
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This paper reports the results of the numerical modeling of gravitationally instable processes in the lithospheric mantle
of ancient cratons. The gravitational instability is considered as a result of melting at the lithosphere base owing to its
local heating by anomalous mantle. Modeling was based on a finite element method in 2D formulation and took into account the
geological structure and thermomechanical parameters of the lithosphere of the Siberian platform. Numerical results revealed
the main tendencies in the mantle diapirisim of the mafic and ultramafic magma ascending through the “cold” high-viscosity
lithosphere. It was shown that the shape of diapiric magmatic bodies is controlled by realistic visco-elastic-plastic rheology
of lithosphere. The ascent of diapir in lithosphere was modeled for diverse regimes differing in duration, temperature field,
and upwelling depth. It was concluded that the ascent of melt through lithosphere to the crust-mantle boundary is mainly controlled
by rheology, and conditions of oscillatory diapirism with recurrent magma replenishments were modeled. Modeling results may
shed light on some features related to the trap magmatism of the Siberian igneous province. The duration and rate of magma
upwelling as well as the parameters of periodical magma upwelling were estimated and attempt was made to explain the high-velocity
seismic anomalies that were recorded in the subcrustal regions of the Siberian platform. 相似文献
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O. P. Polyansky S. N. Korobeynikov A. V. Babichev V. V. Reverdatto V. G. Sverdlova 《Izvestiya Physics of the Solid Earth》2014,50(6):839-852
The numerical model of mantle diapirism and active rifting is developed. The model describes the possibility of extension and thinning of the Earth’s crust under the action of a local 100-km long heat source in the sublithospheric mantle, which causes melting and rising of the magmatic diapir through the cratonic lithosphere. The model combines the mechanisms of the uplifting of the anomalously hot material due to its gravitational instability, underplating of magma beneath the continental crust, and its extension by the forces of the convective flows at the base of the plate. The obtained results shed light on some geological features of the joint formation of the large Vilyui igneous province and Vilyui sedimentary basin. 相似文献
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A.V. Babichev I.S. Novikov O.P. Polyansky S.N. Korobeynikov 《Russian Geology and Geophysics》2009,50(2):104-114
The Altai lithospheric structure has been generally understood due to available high-resolution digital models. As a further step in modeling, we have simulated the structure of southeastern Altai as interaction of eight blocks which comprise or surround the Chuya and Kurai basins, proceeding from the basic configuration of blocks and earthquake mechanisms. Should the stresses in the system remain invariable, the western periphery of the Kurai basin will deform to let the Uimen-Sumulta fault join the Chuya (western end of Tolbonur) fault and evolve further as a single shear zone. The best fit model was one with slip along a single border fault in the middle of the area between two rheologically different terranes. This setting corresponds to a fault boundary between the more plastic Gorny Altai and more rigid Teletskoe-Chulyshman domains, which is consistent with current crustal movements from GPS data. In addition to scientific significance, models of this kind have practical applications as they highlight areas of stress buildup prone to release in large earthquakes. The new approach was applied to simulate the stress and strain patterns of central and southeastern Gorny Altai, and the models were tested against available geomorphological and seismotectonic data. 相似文献
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