Reply to comment by Hillis et al. (2013)

Abstract

We agree that there is now convincing evidence which favours the idea that a region encompassing the British Isles is dynamically supported by convective circulation beneath the lithospheric plate. For example, the coincidence of a long wavelength (>800 km) free-air gravity anomaly with anomalously slow velocities beneath the lithospheric plate suggests that regional elevation of Northern Britain is maintained by a tongue of hot asthenosphere protruding away from Iceland (Jones et al. 2002a; Arrowsmith et al. 2005). These observations are corroborated by the crustal thickness measurements of Davis et al. (2012). The Icelandic plume initiated 62 Ma and there is excellent evidence in the Irminger and Icelandic basins that this plume has waxed and waned with different periodicities (Jones et al. 2002b; Poore et al. 2009). This transient activity has manifest itself in geochemical and earthquake records along the Reykjanes Ridge (Poore et al. 2011; Parnell-Turner et al. 2013), in the Neogene record of deep-water overflow across the Greenland-Scotland Ridge (Poore et al. 2006), and along the fringing continental margins where spectacular buried ephemeral landscapes have been encountered (Shaw-Champion et al. 2008; Rudge et al. 2008; Hartley et al. 2011). Around the British Isles, there is considerable onshore and offshore evidence favouring a history of transient and/or permanent vertical motions which may reflect Palaeogene and Neogene plume activity (White & Lovell 1997; Jones et al. 2001; Jones et al. 2002a; Al-Kindi et al. 2003; Jones & White 2003; Mackay et al. 2005). This regional pattern of epeirogeny is locally complicated by faulting and folding, which is often difficult to date with precision.