Impact Melt Veins in the Central Uplift of the West Clearwater Lake Impact Structure, Northern Quebec, Canada.
Rebecca Wilks, University of Western Ontario, London, ON, Canada and Gordon R Osinski, University of Western Ontario, Earth Sciences, London, ON, Canada
Contact First Author: Rebecca Wilks; rebeccaaiellowilks@gmail.com
Previously Published Material: This material was part of a poster presentation at the Lunar and Planetary Science Conference in The Woodlands, Texas during the week of March 16-20.
English Abstract:
The West Clearwater Lake impact structure is a ~290 Ma impact structure located in Northern Quebec at 56°08′N 74°18′W, approximately 125 km east of Hudson Bay. Phaneritic plutonic target rocks of the Superior Province were impacted, resulting in a ~30 km diameter structure with a series of central islands. The process of impact cratering is still not fully understood, specifically, how the uplift of underlying rocks in the centre of large complex craters occurs. This study intends to investigate central uplifts; particularly impact melt veins and dykes observed in the uplifted target rocks of the West Clearwater Lake impact structure. Researchers have hypothesized that impact generated melt has played a role in the weakening of rocks in the crater floor, allowing for the central uplift process to occur. Melt is thought to lubricate faults, allowing for blocks to be more susceptible to displacement. Whether this melt is formed by the initial shock of the impact or due to frictional melting is unknown. The aim of this research is to better understand the formation processes of these melt veins and dykes.
We have used electron dispersive spectroscopy techniques and optical microscopy to analyze the chemical composition, petrography and mineral structure of three melt vein samples retrieved from the central islands in West Clearwater Lake. In order to determine the processes by which these melt veins formed, petrography and geochemistry data of both the host rock and melt veins have been acquired and used for comparative analysis. This will allow for a better understanding of the role of melt on central uplift formation on Earth and other planetary bodies.
