Grant: Discovery Grants Program - Individual

This research programme investigates the origin of the continental crust through studies carried out in Labrador, which contains some of the most vastly distributed and poorly known tracts of ancient rocks found in Canada. It will specifically address the problem of whether Earth's crust formed in large, episodic bursts of magma from deep within the mantle, or rather more continuous outpourings of magma as might be expected from the modern style of plate tectonics that we see on Earth today. Issues of crust formation are linked inextricably to processes promoting the development of early life; for example the existence of large stable land masses would have allowed terrestrial and shallow water platforms for early organisms. I will determine the age and isotopic composition of minerals that retain the memories of how and when the crust formed using instrumentation that drills out pieces of the minerals with a laser beam and transports them to a mass spectrometer for analysis. The work will be carried out at various locations in Labrador, around the world-class nickel-copper-cobalt ore deposit at Voisey's Bay, along the coast north of Nain, which contains wonderful three dimensional exposures of rocks, and at Mistastin Lake, which was formed by a meteor impact, bringing rocks to the surface that would not otherwise be accessible for study in this area. The minerals will be separated from a variety of types of ancient rocks, and from modern sediments eroded from the ancient rocks by glaciers and streams. Two of the minerals of interest, zircon and baddeleyite, are hard and not easily destroyed by erosion. The diversity of sampling locations and rock types will provide the best chance of providing a complete picture of the nature and characteristics of the magmatic events that formed the Labrador crust. The approach could be used as a template for similar studies of ancient crust formation elsewhere. This work has the potential to spur the interest of other academic researchers and mineral exploration companies to invest time and new resources in Labrador, which is vital for the sustainable development of this region.