Shock-induced remanent magnetisation in late Precambrian rocks from Lake Superior

Abstract

A POSSIBLE shock-induced remanent magnetisation, the direction of which yields a typical ‘Grenville’ pole position has been discovered from late Precambrian Keweenawan igneous rocks (about 1,100 Myr old) on the Slate Islands, situated in northern Lake Superior about 300 miles north-west of the Grenville Front.