163-10 From Vesta with Shock: Refining the Record of Inner Solar System Collisions

Session: Impact Cratering Processes Across the Solar System: In Memory of Dr. Bevan M. French

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Past studies of the patterns and timing of impactor flux throughout the solar system have focused primarily on the lunar record; however, materials from other bodies should also preserve evidence of these broader trends. Asteroid Vesta provides an excellent opportunity to assess the impact flux through time in the inner solar system as the meteorites that originate from it, the howardites-eucrites-diogenites (HEDs) are abundant in modern collections. However, traditional shock classifications based on optical techniques have limited applications at shock levels below the maskelynite-threshold, which is not a common phase in the HEDs. In addition, the current shock classification framework does not account for the diverse mineralogies and compositions of achondrites, particularly olivine-poor basaltic meteorites like eucrites. Without such a framework, our ability to reconstruct the impact histories of these samples, their parent bodies, and the broader collisional evolution of the solar system remains incomplete, limiting our understanding of planetary processes and the role of impacts in planetary evolution.

It is therefore necessary to identify methods that allow the quantification of shock, particularly that occurring at the sub-maskelynite level, in these samples and link these shock stages with resetting events, in order to understand the distribution of impact flux with time within the inner solar system. By applying these methods, we can determine whether the timing of impact resetting on Vesta supports the Late Heavy Bombardment (LHB) hypothesis or indicates a more continuous impact history, refining our understanding of Solar System dynamical evolution.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10650

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