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Please join us for the first lecture in the COMPRES Keynote Lecture Series with:  

Dr. Peter Driscoll
Carnegie Institution for Science
on August 27, 2020 at 2pm EDT 

Zoom link: https://unm.zoom.us/j/99868073877?pwd=QWlVVjRUWWQ3eVpCNDkrOXZGOTRXdz09

Talk title and abstract:

Earth’s Inner Core Age and Paleomagnetic Expression

The age of Earth’s enigmatic inner core (IC) is unknown with estimates ranging from 500 Myr to the age of the Earth itself.  In this talk we review how the IC is thought to have formed and why such a range of age estimates persists.  Given its inaccessibility, we discuss how the nucleation and continual growth of the IC may have influenced convection in the outer core and its observable paleomagnetic expression at Earth’s surface.  We highlight numerical dynamo models driven by a whole-planet thermal evolution model that show the geodynamo could have transitioned from a multipolar to dipolar regime around 1.7 Ga, then to a weak-field dynamo around 1.0 Ga, and finally to a strong-field dipole following IC nucleation around 650 Ma that is maintained to the present day.  Recent paleomagnetic observations from the Neoproterozoic are consistent with a weak non-dipolar dynamo, supporting the possibility of a young IC.  Finally, we discuss several core material properties that are likely to have a first-order effect on the magnetic evolution of the Earth, including the magnitude and depth-dependence of the thermal conductivity.