Physical Records of Impacts in the Early and Modern Solar System

The study of terrestrial meteorite impact craters and of impacted meteorites expands our understanding of cratered rocky surfaces throughout the solar system. Terrestrial craters uniquely expand upon data from remote imaging and planetary surface exploration by providing analogs for understanding the buried sub-surface portions of impact structures, while impacted meteorites provide examples of a much wider range of surface and subsurface impactite materials than we can directly sample thus far through solar system exploration.

This report examines three facets of the impact record preserved in terrestrial impact craters and in meteorites. First, it looks at the macroscopic structure of the Sutters Mill meteorite, a brecciated regolithic CM chondrite that preserves a three-dimensional record of the one of the most primitive known impact gardened surfaces in the solar system. The report details distinct lithologies preserved in the meteorite and the ways in which these lithologies reflect impact and alteration processes, with the intention of contextualizing and illuminating the wider body of recently published instrumental work on the stone by the current authors and others. Second, this dissertation presents a detailed analysis of the origin and nature of unique sub-spherical `round rocks’ commonly associated with the surface exposed sediments at the proposed Weaubleau impact structure, in west-central Missouri. Third, and finally, the dissertation looks at the nature of impact evidence for small impact pits and craters on earth. Unambiguously proving the impact origin of sub-kilometer terrestrial impact craters has presented significant historical challenges. A systematic analysis of field reports for all widely recognized sub-km terrestrial craters addresses both the nature of compelling evidence for impact origin for structures in this size range and the adequacy of the existing record of evidence for currently recognized structures.