The West Orkney Basin is a poorly studied Palaeozoic and Mesozoic rift basin that overlies a highly seismic-reflective Caledonian orogenic basement terrane. This study presents a novel approach of using 2D seismic data to map single intra-basement reflection packages and their relationship to overlying normal faults in the West Orkney Basin. It is demonstrated that the rift architecture of the West Orkney Basin is more linear with a prominence of relay zones relative to previous interpretations, and that rift structures form complex discordant and concordant relationships with pre-rift Caledonide basement structures. Restoration of basement fabrics to their pre-extensional geometry indicates that the reactivation of basement structures as normal faults has occurred only where the pre-extensional-dip of basement structures is greater than 30°. The relatively high density of relay zones mapped in the West Orkney Basin is proposed to be the result of the rift system forming a partially exploitative relationship with basement structure, where extension has been accommodated between segments that have or have not reactivated basement fabrics.

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