CPSH Seminar Series: Simone Marchi, Southwest Research Institute
January 16, 2026
February 23, 2026 at 1:00pm CT
Location: Classroom 15.216B, Physics, Math and Astronomy Bldg.
UT Austin, Department of Astronomy
2515 Speedway, Stop C1400
Austin, Texas 78712-1205
Online: To join online contact Brandon Jones.
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Speaker: Simone Marchi, Southwest Research Institute
Host: Sean Gulick, Marc Hesse
Title: Earth’s wild years: The role of impact processes
Abstract: In the aftermath of the giant collision resulting in the formation of the Moon, about 4.5 billion years ago, the Earth experienced a protracted bombardment by leftover planetesimals. In this talk, I will present a bombardment model of the Hadean Earth (4.5-4.0 Ga) that has been calibrated using existing lunar and terrestrial data. This model shows that the near-surface of the Hadean Earth was widely reprocessed through mixing and burial by impact-generated melt. Further, I will discuss the effects of early collisions on the formation of impact-induced geochemical heterogeneities that could still persist in terrestrial mantle rocks. Finally, I will present a recent impact model for the Archean Earth (4.0-2.5 Ga), and discuss implications for the oxygenation history of Earth’s atmosphere.
Biography:
Dr. Simone Marchi’s research interests include the formation and evolution of terrestrial planets, the Moon and asteroids. He is associated with several space missions, including: NASA’s Dawn, Lucy, Psyche, and ESA’s Rosetta, BepiColombo, JUICE.
He has recently published a trade book, Colliding Worlds.
More details can be found here: http://www.boulder.swri.edu/~marchi/index.html