The British Siluro-Devonian palaeofield, the Great Glen Fault and analytical methods in palaeomagnetism: comments on a paper by K.M.Storetvedt et al.

Late Silurian-early Devonian palaeomagnetic poles throughout the British Isles lie in a coherent group about 1°S and 314°E (A95 = 9.6°). The clustering of these poles, which are derived from 11 individual studies of Siluro-Devonian rocks of all the major tectonic elements of Britain, carries two important tectonic implications:

(1) the British sector of the Iapetus Ocean, recognizable from Ordovician poles, had closed by late Silurian times; and

(2) any postulated mega-shear, whether related to Acadian or Hercynian deformation, is below the limit of palaeomagnetic resolution.

The collective rejection of all Siluro-Devonian results by Storetvedt et al. (1990a, b) is demonstrated to be unfounded.