Grant: Discovery Grants Program - Individual

NSERC 101 Summary It is not known whether the continents formed early in Earth's history, or alternatively grew steadily through time. Ocean crust is continuously formed and recycled into the deep mantle by plate tectonics. Plumes of anomalously hot rock are ejected from Earth's core-mantle boundary at 3000 km depth and erupt to form small volcanic islands like Hawaii or large ocean plateaus such as Iceland. By sampling rocks from ancient ocean islands and plateaus of various ages, preserved in the geological record, it will be possible to answer the question when continents were extracted from the mantle by plate tectonics. The significance of this research is that mineral resources form in continental crust of specific ages, so it is important to understand how and when the continents formed. A second part of the research will address the question of where Earth's oceans and atmosphere came from. Earth's primary ocean and atmosphere were lost during the giant meteorite impact event that created the Earth-Moon system. Our present oceans and atmosphere must have been acquired after that impact, possibly from volcanic gases, meteorites, or comets, each of which has distinct nitrogen-isotope signatures. Nitrogen from Earth's atmosphere is captured by microorganisms, and buried in sedimentary rocks as nitrogen rich hydrocarbon. By analyzing hydrocarbons for nitrogen-isotopes in ancient rocks of various ages it will be possible to answer the question of where Earth's ocean-atmosphere came from.