As a result of recent deep reflection and refraction seismology the
crustal structure of the Western Alps is now quite well-defined.
However, this raises the question of what is present below the Moho,
such as a crustal eclogitic root. This study attempts to estimate the
volume of this eclogitic root on the basis of palinspastic
reconstructions. Even with a minimum estimate of the crustal material
involved in the subduction processes which took place during the Alpine
orogeny, a significant eclogitized crustal root must be present down to
depths of around 100 km below the Po plain. A maximum estimate suggests
that a large part of this root could now be recycled in the
asthenosphere.