Stanford University
Headshot of Dr. Sarah Stewart, UC Davis

Geological Sciences Seminar: Dr. Sarah Stewart, UC Davis

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Faculty/Staff, Students, Alumni/Friends
Department of Geological Science

Large Impacts onto the Early Earth: Planetary Sterilization and Iron Delivery

Late accretion onto the Hadean Earth included large impacts that influenced early habitability, either by sterilizing the planet or alternatively catalyzing the origin of life by delivering iron required to create a reducing environment/atmosphere. Using 3D simulations of large cratering events, we find that globally reducing environments are relatively rare because most of the projectile iron is deposited in the crust and upper mantle, where it is not immediately available to reduce surface water and contribute to forming a reducing atmosphere. The hypothesis that life emerged in the aftermath of large impacts requires an efficient mechanism of harnessing the reducing power of iron sequestered in the crust/mantle, or an origin of life pathway that operates in more weakly-reducing post-impact environments that require smaller quantities of impact-delivered iron.


Dr. Sarah Stewart is a professor in the Department of Earth and Planetary Sciences at U. California, Davis. Stewart studies the origin and evolution of planets. She is a recipient of a MacArthur ‘genius prize’ for her work on planetary collisions and the discovery of synestias. At UC Davis, Stewart directs the Shock Compression Laboratory, which uses enormous cannons to explore the physics of planetary impacts. Stewart was also a featured speaker on for her work on the origin of the Moon.


For Zoom links and other info, please email Rey Garduño  


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