A tomographic inversion of local, regional, and teleseismic phase arrivals recorded by Spanish and Moroccan regional networks images significant P velocity anomalies beneath the Betics, Rif, and Alboran Sea. Evaluation of the resulting velocity model using bootstrap resampling, block shifting, and synthetic tests suggest that a robust high-velocity anomaly is located beneath southern Spain steeply dipping to the SE from depths of about 60 to 400 km. Below this depth the high-velocity anomaly becomes diffuse. A concentrated high-velocity anomaly in the 570 to 650-km layer, although probably poorly constrained, correlates well with the location of the few but significant deep earthquakes beneath southern Iberia. We interpret these high-velocity bodies to represent cold lithospheric material recycled into the upper mantle.
Previous tomographic studies have imaged a single high-velocity body beneath the Betics and Alboran
from about 200 to 650 km depth, but detailed synthetic and error tests that we performed suggest that the apparent
continuity of this high-velocity anomaly may be partially caused by smearing from shallower and deeper depths owing
to poor station coverage within the Alboran Sea. The high-velocity upper mantle body that we mapped is overlain
by a region of low-velocity uppermost mantle beneath the Betics. This velocity model together with recent results
from the latest Alboran ODP leg provide strong evidence that lithospheric delamination (in the sense of) played
an important role in the Neogene evolution of the Alboran region.