Geophysical Journal | 2006 volume 28 5

Geomagnetic field in Phanerozoic and lower-mantle plumes

© Pecherskiy D.M.

Data about amplitude of variation of a geomagnetic field direction and geomagnetic reversal frequency for the last 350 million years are collected and generalized. As a result practically identical tendency to growth of amplitude of geomagnetic field direction variation with approaching to epicentres of recent plumes, Greenland, Deccan, Siberian superplumes and global magnetic anomalies is visible that testifies their equal nature, i.e. all these results are local excitation in the top part of a liquid core. At the same time there is no connection between plumes generation and geomagnetic reversals frequency that eradicates their different sources. "Backlog" plumes magmatic activity on a surface of the Earth from time of its formation at core-mantle boundary is time of plume rise up to a surface of the Earth, in all considered cases it keeps within one limits 20-50 million years. It is possible to explain protraction of time of "backlog" as a result of formation in the specified interval of time of a series of plumes (superplumes) approximately in one area of core-mantle boundary.

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