Geomagnetic secular variations during the last 25 000 years: an interpretation of data obtained from rapidly deposited sediments

Secular variations of geomagnetic declination and inclination recorded by lacustrine and cave sediments from North-west Europe, the Great Lakes region of North America and the Black Sea through the last 25 000 yr have a regional character and therefore cannot be attributed primarily to westward drift which is one of the main features associated with historic secular variations. A geomagnetic model in which the non-dipole field originates from stationary oscillating or pulsating sources situated in the outer core is favoured and the origin of geomagnetic excursions is discussed.