Evaluation of stress and strain rates in the lithosphere of Europe based on high resolution thermodynamic model coupled with mantle convection model.
Final Report Abstract
The development of modern earth sciences dictates extensive sharing of data and methods between different branches of geology, geophysics, earth system and other natural sciences as well as a joint interpretation of the results. This is also very important for solving so-called ill-posed problems, where it is impossible to get a unique solution basing only on one data set that is a common situation for most of the inverse problem in geophysics such as revealing of internal structure of the Earth using only gravity or magnetic fields data measured at the Earth’s surface. One of the main aims of our project was developing and further application such a cross-disciplinary methods, allowing for, in particular, to get more knowledge on the internal structure and stress state of the lithosphere and upper mantle in Europe and adjoining areas. In the course of the project we have developed a multi-disciplinary approach to create an integrative model combining global and regional dynamics of the Earth’s interiors coupled with ice-sheet and climate models. This approach gave us several surprising results. It was recognized that the tectonic history of North Atlantic region during last 100 Myr contributes to the present-day ice loss in Greenland, and as consequence, to the present and future climate. Analyzing the resulting thermal structure of the Greenland’s lithosphere, we also proposed a new track for the Iceland plume passage beneath Greenland, which is, among other things, important for plate reconstructions. Finally, we have introduced a map of alleged sub-glacier aquifers and zones of basal ice melting that is of a key importance for the further ice-sheet dynamics modeling. The results of the study have been published in Nature Geoscience and raised a wide response in media and scientific blogs all around the world. Following our approach, which combines gravity, topography, crustal structure, seismic tomography data and global mantle dynamics model, we have calculated the internal structure, stress state and convection patterns below North America and show that the deepest part of the cratonic root beneath the Superior Province has shifted about 850 km to the west–southwest relative to the centre of the craton. The result is surprising and even provocative since most of Archaean-aged cratonic roots are thought to be stable since their formation and too viscous to be affected by the mantle convection. The results have been published in Nature Geoscience with high response in media and scientific blogs. Basing on our global model, we calculate the stress state, principal stresses and directions for Europe and Arabian plate in several layers of the lithosphere and upper mantle. For the Arabia-Eurasia collision zone we found a subduction polarity reversal, which also contradicts the conventional view and might give a new insight into regional tectonics. The results for the European plate show change in principal stress orientations with depth in several regions of Europe (e.g. Alpine region and Pannonian basin). Since the data might be used as a proxy for seismic anisotropy, it is going to be used in our next project in the framework of DFG SPP2017 and AlpArray for better interpretation of new tomography data.
Publications
- (2015): Effects of the postperovskite phase change on the observed geoid. - Geophysical Research Letters, 42, 1, pp. 44-52
Shahraki, M., Schmeling, H., Kaban, M. K., Petrunin, A. G.
(See online at https://doi.org/10.1002/2014GL060255) - (2015): Cratonic root beneath North America shifted by basal drag from the convecting mantle. - Nature Geoscience, 8, 10, pp. 797-800
Kaban, M. K., Mooney, W., Petrunin, A. G.
(See online at https://doi.org/10.1038/NGEO2525) - (2016): Melting at the base of the Greenland Ice Sheet explained by Iceland hotspot history. - Nature Geoscience, 9, pp. 366-369
Rogozhina, I., Petrunin, A. G., Vaughan, A. P. M., Steinberger, B., Johnson, J. V., Kaban, M. K., Calov, R., Rickers, F., Thomas, M., Koulakov, I.
(See online at https://doi.org/10.1038/NGEO2689) - (2016): Seismic structure beneath the Gulf of Aqaba and adjacent areas based on the tomographic inversion of regional earthquake data. - Solid Earth, 7, 3, pp. 965-978
El Khrepy, S., Koulakov, I., Al-Arifi, N., Petrunin, A. G.
(See online at https://doi.org/10.5194/se-7-965-2016) - (2017): Strength and elastic thickness variations in the Arabian Plate: A combination of temperature, composition and strain rates of the lithosphere. - Tectonophysics
Tesauro, M., Kaban, M. K., Petrunin, A. G., El Khrepy, S., Al-Arifi, N.
(See online at https://doi.org/10.1016/j.tecto.2017.03.004) - (2017): Variations of the effective elastic thickness reveal tectonic fragmentation of the Antarctic lithosphere. - Tectonophysics
Chen, B., Haeger, C., Kaban, M. K., Petrunin, A. G.
(See online at https://doi.org/10.1016/j.tecto.2017.06.012)
