The Zagros orogen in the Iranian Plateau is a natural laboratory in
which to investigate the tectonic evolution of the transition from
oceanic subduction to continental collision. However, where slab
detachment occurred and how slab detachment affects shallower
continental subduction remain poorly understood. The formation mechanism
of the post-collision magmatism is also unclear. Here, we construct a
high-resolution Pn-wave attenuation model for the uppermost mantle
beneath the Iranian Plateau and surrounding areas using a newly compiled
dataset. Weak Pn attenuation delineates the Arabian Plate front near the
Moho discontinuity, extending further toward the subduction direction in
the northwestern and southeastern parts, possibly due to the up-bending
and underplating of the Arabian lithosphere after the loss of slab pull.
The correlations among the surface Miocene-Quaternary volcanism and
strong Pn attenuation in the uppermost mantle suggest that
asthenospheric materials escaped from slab windows and further feed the
post-collision volcanoes.