High Temperature Volcanism on Earth: Physical Volcanology, Mineralogy, and Geochemistry of Archean Komatiites

Komatiites are magnesium-rich magmas characterized by very high temperature (up to 1640°C vs. ~1200°C for modern basalts), very low viscosity (0.1-1 Pa·s), and a very large interval (460-160°C) between liquidus and solidus. As a consequence, they formed highly mobile flows capable of flowing long distances over gentle slopes that - if channelized - thermally and thermomechanically eroded wallrocks and substrates. This led to the formation of some of the world's richest nickel-copper-platinum group element deposits. The most magnesian examples formed only the Archean, marking a fundamentally different thermal structure in the Earth's mantle prior to 2.5 Ga. 

Dr. Lesher is a world renowned expert in komatiites and he will discuss how they can help shine help a light on the Early Earth in the remote past.

Speaker: Michael Lesher, Laurentian University, Sudbury