The crustal structure and tectonic framework of the central Peru Margin, between lat 7° and 10°S were interpreted using mainly a 102 km long, multichannel seismic section and existing geologic and geophysical data in the region. Thrust faulting occurs in upper layer 2 basalts as the Nazca plate descends beneath the continental slope. This produces basaltic ridges (slabs) within the trench axis and at least 26 km landward beneath the overriding continental plate. Broken low-frequency reflectors within this diffracting subduction complex suggest that ophiolitic slivers of basalt are being incorporated into portions of it, forming a sediment-basalt melange.

Three prominent...