RICERCA ITALIANA     

Structural and magmatic constraints for the study of Central Mediterranean orogens

Università degli Studi di Napoli "Federico II"

Abstract

Magmatolgy, geophysics, brittle-ductile structural geology, are disciplines that must cooperate in geodynamics investigation. The four research groups have got togheter with such aim. The project plans to provide new data and intepretations for contributing to understand mechanism controlling the geodynamic evolution of Central Mediterranean convergence and subduction areas, by comparing fossil (exhumed) examples in key areas of the Alpine and Apennine chain, and in parts of Aegean West Anatolia chain.

The targets are:
- To estimate shortening and convergence rates
- To analize the relationships between sin- and post- compressive deformation in brittle and ductile context
- To reconstruct the relationship between past and present horizontal and vertical velocities
- To study the relationship between the velocity of subduction and the amount of associted magmatic products
- To study causes determining the depth of magma sources between 100 and 150 km
- To analyse the influence of inherited lithospheric variations on both structure of the oorogen and magma geochemistry
- To study the role played by different tectonic elements (sedimens, oceanic and continental crust, mantle) in the geochemical characterizing of orogenic and intraplate magma sources within subducting context.

The methods that the 4 RU (Napoli, Roma, Pisa, Milano) will use are:
- Structural geology mapping of brittle and >>>

Principal Investigator

Alberto INCORONATO Università degli Studi di NAPOLI "Federico II"

Research Objectives

The main aim of the project is to provide integrated contribution to the magmatic and structural studies of central Mediterranean orogens, in order to shed light into processes which govern the dynamics of subduction and collsion zones. This will be achieved by studying exhumed and active cases exposed in key areas of the Alpine and Apenninic chains, and comparing these cases to areas of the Aegean and Western Anatolia area. Modern geodynamic models require the integration of data and interpretation from different disciplines. The membres of the different RUs (Research Unit) have alredy carried out jointly multidisciplinary researches. Aware of the potential of such an approach, a research program bearing to still controversial geological models is proposed
One of the main reserach topics is to better define how the lateral thickness and compositional variations of the subducting lithosphere and the structural discontinuities inherited during the pre- and syn- subductive phases control the geometry of the accretionary wedge and the evolution of the collisional belt, and possibly influence the heterogeneities of the related magmatism.
As far as the Central and Southern Apennines (modern example of a subduction-collision zone) is concened it is proposed:
- to investigate the structure of the accrectionary prism in order to reconstruct depth and kinematic of the decollment planes;
- to characterize the deformation field and the relationship between >>>

Timescale

24 months

National and international background

Within the Central Mediterranean, the effects of subduction and collisional processes show a large spatial and temporal variability, which is documented in different orogenic segments built at the expenses of lithospheric blocks trapped in between Africa and Europe convergence. As a matter of fact, fossil subduction wedges are exhumed in the Alps and exist alongside with the peri-Adriatic active margins, where the transition between subduction and collision is younger or still ongoing and controls the present deformation and magmatic processes. An integrated investigation of subduction, collision and post-collision effects within fossil and active settings may provide important insights into the interaction between contraction and extension and on the magmatic evolution in different stages characterizing the evolution of laterally variable lithospheric segments.
During the last years the knowledge on subduction zones increased significantly thanks to a tight integration of several different sectors of the Earth Sciences, such as structural geology, basin analysis, petrology, seismology, geodesy and geodynamics. This multidisciplinary approach was fruitful also for the subductions in the Mediterranean area, for which we now have highly accurate tomographic snapshots of lithosphere and upper mantle (Piromallo and Morelli, 2003), and where an important contribution to the understanding of the geodynamic evolution can derive from an integrated investigation of accretion >>>