UC Berkeley

Interactions between the core and the mantle arise when heat, mass, momentum, or charge is transferred across the core-mantle boundary (CMB). Each of these interactions has consequences for the dynamics and evolution of the Earth's interior. Thermal interactions are a result of changes in the magnitude or spatial pattern of heat flow across the CMB. These interactions evolve slowly on the timescale of convective overturn in the mantle (nominally 107-108 years). The style of convection in the core and the regeneration of the magnetic field can be dramatically altered by plausible changes in CMB heat flow. Electromagnetic and mechanical interactions occur on shorter timescales and may be responsible for observed fluctuations in the Earth's rotation rate over periods ranging from several decades to several days. More uncertain are chemical interactions, which result from the transfer of mass across the CMB. Differences in the oxidation state of the core and the mantle make chemical reactions between these two regions likely, yet the evidence for mass exchange remains controversial. We review recent advances in our understanding of core-mantle interactions. We also explore the role of core-mantle interactions in making internal processes detectable at the Earth's surface.