THE IAPETUS SUTURE ZONE IN ENGLAND, SCOTLAND AND EASTERN IRELAND - A RECONCILIATION OF GEOLOGICAL AND DEEP SEISMIC DATA

Deep seismic profiles in the Irish and North seas have successfully imaged crustal structure across the Iapetus suture zone. A problem with current interpretations is that the reflectors chosen as the suture project to the top of the basement well to the south of the Solway Line, the palaeontologically defined trace of the suture. We present a revised interpretation in which a reflectivity boundary common to all the profiles is identified as the leading edge of imbricated Avalonian crust, in effect the footwall of the suture zone. This projects to the surface close to the Solway Line, obviating the need to invoke northward backthrusting of the suture.