Crameri, F;
Lithgow-Bertelloni, C;
(2017)
Abrupt upper-plate tilting during slab-transition-zone collision.
Tectonophysics
10.1016/j.tecto.2017.09.013.
(In press).
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Abstract
The sinking remnant of a surface plate crosses and interacts with multiple boundaries in Earth's interior. Here, we specifically investigate the prominent dynamic interaction of the sinking plate portion with the upper-mantle transition zone and its corresponding surface elevation signal. We unravel, for the first time, that the collision of the sinking slab with the transition zone induces a sudden, dramatic downward tilt of the upper plate towards the subduction trench. Unraveling this crucial interaction was only possible thanks to state-of-the-art numerical modelling and post-processing. The new model that is introduced here to study the dynamically self-consistent temporal evolution of subduction features accurate subduction-zone topography, robust single-sided plate sinking, stronger plates close to laboratory values, an upper-mantle phase transition, and simple continents at a free surface. To distinguish the impact of the new physical model features, three different setups are used: the simplest model setup includes a basic high-viscosity lower mantle, the second adds a 660-km phase transition, and the third includes, additionally, a continental upper plate. Common to all models is the clear topographic signal upon slab-transition-zone interaction: the upper plate tilts abruptly towards the subduction trench by about 0.05° and over around 10. Ma. This dramatic increase in upper-plate tilt can be related to the slab-induced excitation of the high-viscosity lower mantle, which introduces a wider flow pattern. A large change in horizontal extent of inundation of up to 900. km is observed as a direct consequence of the upper-plate tilting. Such an abrupt variation in surface topography and inundation extent should be clearly visible in temporal records of large-scale surface elevation and might explain continental tilting as observed in Australia since the Eocene and North America during the Phanerozoic.
Type: | Article |
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Title: | Abrupt upper-plate tilting during slab-transition-zone collision |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1016/j.tecto.2017.09.013 |
Publisher version: | http://doi.org/10.1016/j.tecto.2017.09.013 |
Language: | English |
Additional information: | © 2017 Elsevier B.V. All rights reserved. This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions. |
Keywords: | Upper-Plate Tilt; Upper-Mantle Transition Zone; Subduction Dynamics; Surface Topography; Numerical Modelling |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
URI: | https://discovery.ucl.ac.uk/id/eprint/10036530 |
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