Palaeomagnetism of the Great Whin Sill

Abstract

The Great Whin Sill, which was intruded in Upper Carboniferous to Lower Permian times, has been sampled at 36 sites in Northumberland and Durham. It was found to be magnetically stable, the site mean direction of magnetization being 187°.8−4°.9 and the mean pole position lying in latitude 37°.3 N longitude 168°.9 E. The distribution of the mean directions of magnetization at these sites is not circular but oval, with the variation in the direction of the palaeomagnetic longitude about twice that in the direction of palaeomagnetic latitudes. However the poles calculated from the site mean directions of magnetization have a circular distribution, and this observation leads to proposal of a method of calculating the errors associated with the palaeomagnetic pole positions.