[DLS] Jon Aurnou (UCLA)

“On Dynamo Action in Earth’s Basal Magma Ocean”

It is argued that the early geomagnetic field must have been maintained in a relatively thin molten silicate ocean situated just above Earth’s liquid metal core. Here, we carry out detailed numerical models of such a thin layer dynamo. When coupled to models of both Earth’s thermal evolution and rotating convective turbulence, we find the electrical conductivity of the basal magma ocean (BMO) fluid is too low for dynamo action to have occurred. This finding likely requiring alternative mechanisms for generating Earth’s ancient magnetic field, a result relevant to the interpretation of ancient paleomagnetic signatures, Earth’s global-scale dynamics, and long-term planetary evolution.

EAPS Department Lecture Series —

Weekly talks aimed to bring together the entire EAPS community, given by leading thinkers in the areas of geology, geophysics, geobiology, geochemistry, atmospheric science, oceanography, climatology, and planetary science. Runs concurrently with class 12.S501.

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