Mantle plumes and magnetic reversals: A surprising link



The history of magnetic field reversals has been described as one of the best known, but least understood, geophysical records on Earth. In contrast, it is only recently that attempts have been made to quantify the history of mantle plume activity. Mantle plumes consist of large volumes of material from the lower mantle that occasionally rise, by buoyancy, from just above the core/mantle boundary.

There is no agreement on the cause of magnetic field reversals, nor on how processes above the core/mantle boundary might influence processes below in the outer core, or even if such influence is possible [Loper, 1992]. However, the suggestion by Larson and Olson ]1991[ that mantle plume activity controls magnetic reversal frequency follows a trail of thermodynamic logic that could shed light on these questions, and thus it is important to understand the basis of such a premise, and how it might be tested.