Geophysical images of the deep crust; the Iapetus Suture

Previous work identified the Iapetus suture as a NW-dipping feature. New depth-migrated data interpretations agree well along 100 km of the strike of this structure in the N Irish Sea, and magnetotelluric stations in the area confirm a thin NW-dipping slab of high conductivity. A contour map of the (?)mylonitic suture trace can be constructed down to and through the Moho at 28 km depth, which suggests crustal stretching below the Solway basin. The zone shows good seismic reflection layering, high conductivity and an increase in P-wave velocity over its width. Crustal refraction experiments can be misleading: a combination of seismic reflection and geoelectric methods may be the best means of determining deep crustal structure.