Antoniette Grima

“Understanding the mantle dynamics that sustain the NeoTethys subduction and the processes that govern plate dynamics throughout super continent break-up and accretion.”

PhD project title:

The NeoTethys subduction, a case for sustained lateral and vertical dynamic flow.

Antoniette Grima

Project description:

The NeoTethys subduction zone, presently limited to a narrow remnant ridge in the Eastern Mediterranean played a fundamental role in the break up of Pangea and in the continental reorganisation of much of present day Eurasia. Initiation of subduction is a matter of debate, however, subduction at this ridge has been consistent from 200Ma onwards with the destruction of the PaleoTethys, the MesoTethys and currently the Eastern Mediterranean crust, the latter potentially being the oldest oceanic crust on Earth.

While the plate dynamics related to the NeoTethys subduction are generally well constrained, the underlying mechanisms that produced and sustained the subduction process are not. The aim of this project is to understand the role of mantle dynamics and dynamic topography on the NeoTethys subduction zone from the Jurassic to present day, including the major plate reorganisations of the Mediterranean at 30 and 15Ma and its present day deformation. The project also seeks to find evidence or otherwise of a hypothesised Tethys Mantle Conveyor Belt, the presence of which could explain many of the Tethyan features spanning from the Himalayas to the Mediterranean over a period of 200 Myr.

This project will model mantle flow including past dynamic processes, while isolating vertical changes in the preserved field due to unrelated isostatic processes, to constrain dynamic topography. The components of mantle convection and drag will be analysed through the comparison of different tomographic models, these being constrained by seismic anisotropy and hence, very useful indicators of asthenosphere flow. Predictions will then be compared to plate reconstructions models and present day satellite-derived gravity and topography fields.

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