REGIONAL-SCALE TECTONIC EVOLUTION AND THE SEISMIC VELOCITY STRUCTURE OF THE LITHOSPHERE AND UPPER-MANTLE - THE MEDITERRANEAN REGION

We present a numerical modeling approach, designed for the verification of tectonic reconstructions and for a quantitative analysis of the seismic velocity structure of the lower lithosphere and upper mantle. In this forward modeling procedure we use published reconstructions of the tectonic evolution of a region to predict the thermal structure, from which we calculate physical quantities like P wave velocity, basin subsidence and basement heat flow. We show an application of this approach to two reconstructions of the late Mesozoic and Cenozoic evolution of the Mediterranean region. The resulting synthetic velocity models are tested against seismological models of the mantle structure, obtained independently by delay time tomography. Subsidence and heat flow predictions are compared with actual observations to further constrain the geological assumptions underlying the forward models. The mantle models predicted from reconstructions of the evolution of the Mediterranean region correlate with major features in the tomographic images. From our model results we conclude that the present distribution of seismic velocities in the Mediterranean region is largely determined by the tectonic evolution during at least the last 40 m.y. This means we can verify processes represented in different tectonic scenarios with the seismologically determined velocity structure. Seen from a different perspective, the model results contribute to understanding the causes of the velocity structure imaged by delay time tomography by showing how the tectonic evolution results in this structure.