Scientific Focus

Peridotite Workshop 2005 [Lanzo, September 27-30, 2005]

       Structural and petrologic-geochemical records in the mantle lithosphere

    This Meeting is aimed to compare the up-to-date mineralogical, petrologic, geochemical and structural knowledge of mantle rocks brought to the surface during volcanic activity (peridotite xenoliths), exposed at the surface as a result of tectonic processes (orogenic and ophiolitic peridotite massifs) or sampled on the ocean floor (abyssal peridotites).
    These occurrences record very different magmatic, metamorphic and metasomatic imprints, which are peculiar of the different geodynamic settings of origin and testify for the complexity of the chemical-physical processes which accompany the dynamic evolution of the upper mantle.
Knowledge of the lithospheric upper mantle based on studies on orogenic and oceanic peridotites and mantle xenoliths has been greatly improved in the last decades. The significant improvement of the analytical tools and new methodological and conceptual approaches promoted significant deepening of present understanding of composition and evolution of the convective mantle, melt production in the asthenosphere and melt migration though the mantle lithosphere.

The focus of the symposium is to:

  1. constrain the variability within each mantle record;

  2. discuss the processes responsible of the observed variability;

  3. evaluate the control exerted by the geodynamic environment;

  4. promote combined geological, geophysical, petrologic and geochemical approaches to understand the mechanisms of the convective mantle dynamics resulting in compositional and isotopic heterogeneity of the different mantle sectors.

    Particular attention will be dedicated to the processes of depletion, refertilization, thermochemical and thermomechanical erosion of the lithospheric mantle, and of asthenosphere/lithosphere interaction that are produced by the diffuse and reactive percolation of asthenospheric melts through the mantle lithosphere. These processes lead to substantial modifications of the chemical composition and physical and rheological characteristics of the lithospheric mantle, at the different geodynamic settings. Recent researches demonstrate that most of the mineralogical and geochemical features of the mantle rocks sampled at lithospheric levels, i.e. xenoliths in basalts and kimberlites, orogenic and ophiolitic peridotite massifs, and abyssal peridotites, are the result of the interaction with melts migrating through the lithospheric mantle column.
    Accordingly, the Meeting is of particular interest for presenting results of petrologic, geochemical, geophysical, structural and isotopic researches on orogenic continental and ophiolitic peridotites, abyssal peridotites and mantle xenoliths in basaltic and kimberlitic volcanites.