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   Maps of the distribution of the flexural rigidity of the lithosphere and
   its effective elastic thickness for the Arctic zone of the Russian Federation

The elastic characteristics of the lithosphere are important parameters that determine the initiation and development of tectonic processes, the deformation of the lithosphere, and the propagation of seismicity
[Watts, 2001]. The flexural ridigity of the lithosphere (D) and the effective thickness of the elastic plate (Te) are usually used as such parameters.

These parameters correspond to a homogeneous infinite plate, which will deform under the influence of an external load in the same way as a real inhomogeneous lithosphere. They are related by the following relation:
                                               
where E = 100 GPa is Young's modulus, σ = 0.25 is Poisson's ratio.

Due to the elastic properties, the plates are able to withstand external loads. For example, volcanic islands (Hawaii, Iceland) create a load with their weight, as a result of which a deflection of the lithosphere is formed around them. This downward deflection results in formation of troughs of great depth around the volcanic islands. From the point of view of geodynamics, the shape of some large sedimentary basins may be due to a similar elastic bending.

Not the entire lithospheric plate is an effective medium for the propagation of elastic stresses. Only its upper part has the necessary rigidity. The lower part of the lithosphere, which is hotter, is usually called inelastic. The inelastic lithosphere is subject to solid-state creep processes, which result in relaxation of elastic stresses.

In this study, we used the same method for determining the elastic parameters of the lithosphere as in
[Kaban et al., 2018]. It is based on cross-spectral analysis of data on the gravity field and near-surface load. An important addition compared to previous works was the use of not only topography data as a surface load, but also the density inhomogeneities of the sedimentary cover. An improved model of these inhomogeneities was obtained in [Sidorov et al., 2021].

As a result, distribution maps of the flexural rigidity (in Nm) and effective thickness (in km) of the elastic lithosphere were built for the Arctic zone of the Russian Federation. These maps are supposed to be used to refine the thermal model of the lithosphere and study its dynamics, associated, in particular, with seismicity.

Maps of flexural rigidity and effective elastic thickness of the lithosphere were constructed for the entire Arctic zone of the Russian Federation. A detailed map of the effective elastic thickness with a spatial resolution of 10x10 km was also built for Northeastern Eurasia.

Mapping data is freely available

Data is have the following designations:
D-arctic.dat lithospheric flexural rigidity data file,
EET-arctic.dat lithosphere effective elastic thickness data file,
EET-NEA.dat data file of the detailed map of the effective elastic thickness map for Northeastern Eurasia,
lithosphere_format.ru.pdf - data format description.

Map 1

Map 2


Map 3

References

    Kaban, M. K., Chen, B., Tesauro, M., Petrunin, A. G., El Khrepy, S. & Al-Arifi, N. (2018). Reconsidering effective elastic thickness estimates by incorporating the effect of sediments: A case study for Europe. Geophysical Research Letters, 45 (18), 95239532. https://doi.org/10.1029/2018GL079732.

    Sidorov, R. V., Kaban, M. K., Soloviev, A. A., Petrunin, A. G., Gvishiani, A. D., Oshchenko, A. A., Popov, A. B. & Krasnoperov, R. I. (2021). Sedimentary basins of the eastern Asia Arctic zone: new details on their structure revealed by decompensative gravity anomalies. Solid Earth, 12(12), 2773-2788. https://doi.org/10.5194/se-12-2773-2021.

    Watts, A. B. (2001). Isostasy and Flexure of the Lithosphere. Cambridge University Press.

URL:   http://www.wdcb.ru/arctic_antarctic/arctic_rigidity.html

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