A palaeomagnetic study of Eocambrian tillites in Scotland

Two main components of magnetization of the mid-Dalradian Port Askaig formation can be isolated of which one, at least, appears to have been acquired at the time of formation of the deposits. The magnetization was acquired while the rocks were in low palaeolatitudes, less than 10°s., which, if the glacial ice-cap origin is correct, would support the concept of a worldwide glaciation in Eocambrian times. The second component of magnetization appears to have been added in Ordovician-Silurian times during metamorphism, by which time the region was in a latitude of some 40°s. Comparison with coeval results for Greenland and Norway suggests that the proto-Atlantic was small at this time, in contrast to a wide Tethys Ocean. Further studies in the North Atlantic region are required to confirm these preliminary findings.