Contributions of rock magnetism and paleomagnetism to recent geophysical advances

The origin of natural remanent magnetization (NRM) in rocks is discussed both in terms of types and carriers of NRM. The importance of the concept of pseudo-single domain (PSD) grains as carriers of stable remanences is underscored. Recent advances in rock magnetism and paleomagnetism have helped to understand (a) continental motions which took place in the first 4 billion years of the earth's life, (b) fine details of field fluctuations both during "normal" times as well as during a geomagnetic field reversal, and (c) indicate the magnitudes of the fields present during the formation of the moon and of the early solar system.