Integrating precise U-Pb geochronology and paleomagnetism: breackup, drift and reassembly of Canada's cratonic elements

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Canada is a collage of crustal blocks and terranes that have come together over most of Earth's history, appearing quite different today than it did by the end of the first great interval of geological time (the Archean).  My research involves the use of high-precision uranium-lead (U-Pb) geochronology to understand the detailed growth and demise of the Earth's crust and how its component parts were gradually assembled. Canada is unique in that it preserves several very old blocks of crust (cratons), older than 2.5 (and locally >4.0) billion years old - each of which are crosscut by swarms of mafic magmas (diabase dykes) that intruded larger cratonic areas as the blocks began to rift and drift apart.  By 1.8 Ga (billion years ago), the resulting reassembled organization of cratonic blocks and their dykes were swept together into a new supercontinent (Laurentia). Precise dating of mafic dykes is useful because the age also records the time when the direction of the Earth's magnetic field was 'frozen in' and from this, the paleolatitude and orientation of the dyke and its host craton can be deduced. I propose to determine Paleoproterozoic continental reconstructions, mostly between 2.5-1.8 Ga,  involving selected Canadian Archean cratonic blocks (Superior, Slave and Nain provinces) by: (1) obtaining precise ages for mafic dyke swarms on the different cratonic blocks, and matching conjugate sets, where possible, (2) identifying the extent and geometry of these events on the blocks, and (3) establishing and comparing primary paleomagnetic poles for precisely-dated events on the different cratons (i.e. using the "key pole" method).  Once a more complete record is better understood for these three relatively well exposed blocks, more meaningful comparisons can be made with other cratons worldwide that may have been kindred ancient terranes during the late Archean. A program of craton-scale hafnium and neodymium isotopic studies of these Paleoproterozoic dyke swarms will assess the nature of hypothesized mantle plume sources for these Large Igneous Province magmas.