Larry Haskin Memorial Colloquium: Gordon Osinski

Impact craters as probes of planetary crusts

Gordon "Oz" Osinski

NSERC/MDA/CSA Industrial Research Chair in Planetary Geology, Depts. of Earth Sciences, Physics & Astronomy, University of Western Ontario

Abstract: In recent years, it has become widely accepted that impact cratering is one of, if not the, most fundamental geological processes in the Solar System. Indeed, impact craters are one of the most common geological landforms on the majority of rocky terrestrial planets, asteroids, and many of the rocky and icy moons of the inner and outer Solar System. It is also now apparent that impact events have profoundly affected the origin and evolution of Earth, including life itself, and producing benefits in the form of economic mineral and hydrocarbon deposits.

A unique result of the impact cratering process is that material is excavated or uplifted and exposed at the surface from various depths in target sequence. As such, impact craters provide probes of planetary crusts where drilling more than even a few metres will not be feasible for the foreseeable future. While this is relatively well known, there remains considerable confusion and even controversy with respect to the depth from which materials are derived in a particular impact setting. In this respect, impact craters on Earth provide the only ground truth data on which to base interpretations of remote planetary data and returned samples. This presentation will showcase some of the best preserved and exposed impact craters on Earth and how they can inform us about the origin of ejecta deposits and central uplift structures in so-called complex impact craters, and constraining their use as probes of planetary crusts.