topoAtlas

Our group has been involved in this 4-year project (2007-2010) funded by the Spanish Government to better understand the processes forming the topography of the Gibraltar Arc and the Atlas Mountains and its interaction with the geodynamics of the Iberia-Africa tectonic-plate boundary. This study has integrated recent data of structural geology and sedimentary infill with quantitative models of compressional tectonic deformation, thermodynamics of the lithosphere and sediment transport. To that purpose, we used numerical modelling techniques to evaluate the relative importance of those processes and their interactions.

The Gibraltar Arc has been the scenario for the events leading to the Messinian Salinity Crisis in the Mediterranean, in which vertical tectonic motions have been seen as responsible for the isolation and desiccation of that sea. We have addressed quantitatively (through process numerical modeling) the inter

The Atlas chain, which reaches in Morocco an elevation above 4000 m and a width of 140 km, is an intraplate alpine chain characterized by a relatively small amount of tectonic shortening (< 25 km). Surprisingly, there is no relevant sedimentary foreland basin in the Atlas, in contrast with most compressional orogens. Recent geological and geophysical studies in this area suggest that these features are due to a buoyant force related to the thinning of the lithospheric mantle. The modelling of the present lithospjheric structure proposed in this project, based on potential fields (gravity, geoid), will permit to better know the nature of this thinning, based on the updated geophysical and field data and the present structure of the upper crust and the lithosphere.

The main outcomes of the project have been:

• We found a quantitative compatibility between the lifting of the Atlas and the Gibraltar Arc and the isolation of the Mediterranean during the Messinian (paper submitted). Details here.
• We found theoretical models and field evidence suggesting that the water entering the Mediterranean after the Messinian Salinity Crisis produced a >200 km long erosional channel of several hundred meters depth, and that this erosion triggered a remarkably rapid filling of the Mediterranean after the Messinian desiccation (Garcia-Castellanos et al., 2009, Nature).
• We have constrained the structure of the lithosphere beneath the Atlas and the Moroccan margin (Jimenez-Munt et al., 2009, Tectonics; Jiménez-Munt et al., 2011, JGR).

Project proposal (in spanish, english abstract).