"Shocking Rocks on Earth and Beyond" by Professor John Spray

Professor John Spray is Director of the Planetary and Space Science Centre at the University of New Brunswick in Canada. He currently manages a research team of 6, comprising research scientists, engineers, postgraduate students, and staff. The team focusses on investigating planetary materials, frictional melting, impact cratering mechanics, the geology of the Moon and Mars, and processes associated with hypervelocity impact and shock effects. John received his BSc in Geology from Cardiff University, Wales, and his PhD in Earth Sciences from Cambridge University, England.

He held the Canada Research Chair in Extreme Deformation and Planetary Materials from 2006-2018. He is a co-investigator on the science teams for NASA’s Mars Science Laboratory (MSL) and the ESA’s ExoMars missions.

'Shocking Rocks on Earth and Beyond'

Abstract: Many geological processes are slow – taking hundreds, thousands, or millions of years to complete. This presentation considers “fast” geology and what can be planetary-scale catastrophic events occurring in seconds and minutes. The hypervelocity impact of asteroids and comets with Earth and other solid planetary bodies generates shock waves that pass through the target materials. Interaction of the shock wave with rock results in bulk and localized deformation and heating. We explore some of these effects as revealed in terrestrial impact structures: Vredefort (South Africa), Manicouagan and Steen River (Canada), as well as in meteorites. Shock can generate extreme pressures (10s of GPa) and temperatures (2000 °C or more) in very short times (typically less than 1 second), conditions normally realized deep inside planetary interiors.

This can result in the formation of unusual mineral species. Some of these shock-generated products are refractory and very tough, so may have potential use in materials science applications (e.g., aerospace and space engineering). Examples of new, shock-generated minerals will be presented from terrestrial and extraterrestrial materials, and we will discuss how they were discovered and how they may be of use to society for future applications in extreme environments.