Some Recent Studies of the Pre-History of the Earth's Magnetic Field

Abstract

In 1952 a study of the remanent magnetism of certain sedimentary rocks of the Triassic system in Britain was begun in the Physics Department of the University of Manchester. This work was transferred in 1953 to the Imperial College of Science, London, where it has been continued and extended. Measurements have now been made not only on Triassic rocks taken from a wide area of England, but also on certain older sediments of the Carboniferous and Devonian systems.
The results provide strong evidence for the hypothesis that the land mass which now constitutes Britain has rotated at some period in geological history relative to the geographic poles. This rotation, which amounts to between 30° and 35°, may have occurred during the late Triassic era, or at some subsequent time.
The measurements have already been described and discussed in detail elsewhere, (1) and the present communication will be confined to a brief summary of the findings and conclusions.