Project Title: Topographic response to lateral changes in subduction polarity

Supervisor: Manuel Fernandez, Jaume Verges

Objectives: To test whether lateral change of subduction polarity can explain the evolution of the Westernmost Mediterranean and to estimate its topographic effects. This will involve the implementation of 2D petrological-geophysical models along transects crossing the east-Alboran and Algerian basins to i) unravel the crust and upper mantle structure with available seismic, petrological and potential field data that fit also the elevation; and ii) relate the differences between the margins of both transects to processes of subduction with opposed polarity and the retreating plates. These results will be compared also with 3D dynamic and analogue models.

Expected Results: Feasibility assessment of the proposed process based on subduction with lateral opposed polarities. Numerical and analogue models will provide knowledge of the primary processes acting in this complex setting where opposed subduction and slab retreat generate differentiated surface topography and crust and upper mantle structures. The application to the Westernmost Mediterranean will give important clues on the evolution of this complex region dominated by coeval extension and compression, asymmetric topography in the conjugate margins, orogenic and anorogenic volcanism, and opposed distribution of HP-LT metamorphism.

Academic secondment: UniRoma3, 3-6 months, analogue modelling. Geosciences Montpellier and Rennes, numerical modelling and field data. Industry secondment: STATOIL, 2 months, hydrocarbon exploration strategies in subduction settings.

Links to other projects: Testing topographic response to roll-back subduction processes in the upper plate (ESR1,4,6); Comparison with similar approaches in the Westernmost Mediterranean (ESR5,10)