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How does the Thermo-compositional Structure of the Australian Lithosphere Influence Strength Variations?тезисы доклада
- Авторы: Tesauro M., Kaban M.K., Petrunin A.G., Aitken A.
- Сборник: 27th General Assembly of the International Union of Geodesy and Geophysics : Programme
- Тезисы
- Год издания: 2019
- Место издания: IUGG Montréal
- Первая страница: 1445
- Последняя страница: 1445
- Аннотация: The results of the geophysical campaigns conducted in the Australian continent in the last decades revealed a complex lithospheric structure and tectonic history, occurred with the accretion of the Archean cratons in the west with the Phanerozoic provinces in the east. In this study, we construct a thermal model of the lithosphere based on the surface heat flow data and seismic tomography model AusREM. For this purpose, first we estimate distribution of the radiogenic heat production in the crust using an empirical relationship with seismic velocities and then, temperature variations assuming steady state conditions. In the upper mantle we discern temperature and compositional variations by applying an integrative technique, which jointly interprets seismic tomography and gravity data. The results show that both the Precambrian West and North Australian Cratons (WAC and NAC) possess thick and cool lithosphere that is depleted in composition (Mg#>90). Hotter and less dense lithosphere is found fringing the eastern and southeastern margin of the continent, resulting from the thermal perturbations of these regions in response to Mesozoic and Cenozoic events. We use the thermo-compositional model to construct two alternative models of the strength and effective elastic thickness of the lithosphere. The first model assumes a constant value of the strain rates, while in the second one, we used the values obtained from a mantle flow dynamic model. The results of the second model show larger variability of the rigidity of the plate within the cratonic areas, reflecting the long tectonic history of the Australian plate.
- Добавил в систему: Петрунин Алексей Геннадиевич