Paleogeographic and tectonic models of the Western Mediterranean

Recent advances in plate modelling and deep-earth visualisation software present excellent opportunities to integrate spatial and temporal data from several earth science disciplines. These tools can enhance our understanding of tectonic and palaeogeographic evolution, with clear applications to resource exploration.

We present a case-study of our geodynamic visualisation package, in which we integrate ‘traditional’ rigid tectonic elements alongside dynamically evolving plate boundaries, tectonic and thermal events and paleogeographic mapping. We focus on the Western Mediterranean, where our developed tectonic model is derived from potential field data, structural analysis, and crustal architecture interpretations. Our model forms the basis for interpretations of palaeogeography at key reconstruction ages throughout the Cenozoic evolution of the area.

Our crustal architecture interpretations illustrate the nature of the crust and its deformation since Variscan. Key components of the model include: Variscan age fold and thrust belts in Iberia, a Cenozoic oceanic domain (Algerian-Ligurian-Provencal Sea) bounded by a magma-poor continent-ocean transition domain, a relatively undeformed continental block (Corsica-Sardinia) and a large expanse of attenuated crust associated with the rapid roll-back of the Calabrian Arc. Our model is constrained by both structural interpretation of gravity and magnetic data and their derivatives and 2D gravity and magnetic modelling of crustal profiles to match the observed signature. The 2D crustal models confirm crustal thicknesses and density to aid the interpretation of crustal type, particularly in the continent-ocean transition where the geophysical signature can help to understand the role of magmatism, hyperextension, or mantle exhumation.

Our tectonic model comprises a rigid, kinematic terrane reconstruction showing the evolution of geologically unique terranes through time, and a dynamic plate reconstruction constrained by geodynamically modelled plate boundaries. Rigid terranes in the model show the detailed tectonic evolution of the Western Mediterranean by reconstructing fault-bounded blocks using Euler rotations derived from geological and geophysical observations. Dynamic elements of the model show a bigger picture tectonic evolution including long and short-lived plates bounded by active tectonic boundaries. Together these elements illustrate the full tectonic evolution including rigid blocks, deforming margins and palaeo-oceanic domains.

We also present an attributed catalogue of tectono-thermal events, which describe the location, age and duration of key events that have occurred through time; visualisation of these events aims to assist with understanding the thermo-tectonic evolution of potential resource exploration targets and geothermal prospectivity.   

Paleogeographic and landscape evolution models are built alongside the tectonic model allowing iterative refinement of the models. Palaeogeographic interpretations include gross depositional environments, the cause and timing of uplifted and eroding areas, and likely lithologies in depositional areas. We build digital elevation models for each stage which are constrained by palaeogeographies and drainage networks. This palaeogeographic module therefore illustrates source-to-sink relationships, which is key for exploration across a range of energy sectors.