The detrital zircon record of Proterozoic orogenic unroofing : case studies from Laurentia

Investigating sedimentary successions broadly contemporaneous with supercontinent amalgamation is critical to understanding sediment dispersal in response to convergent tectonics. At the heart of North America lies Laurentia, a complex of crustal fragments accreted during the broader assembly of the supercontinent Nuna. Sedimentary basins across Laurentia are hypothesised to have recorded the erosion of uplifting orogens in the aftermath of the supercontinent formation. This hypothesis is tested on three basins in the Northwest Territories and Nunavut, Canada (specifically the ~1.9 Ga Nonacho basin, ~1.9 Ga the East Arm basin, and the ~1.6 Ga Elu basin), which have thus far lacked stratigraphically complete geochronological analysis. The resilient detrital mineral zircon acts as a tracer from the source area to the sediment sink, and through its geochronology, the provenance of these three basins can be investigated. The results notably show that all three basins preserve material unroofed from orogenic topography related to the assembly of supercontinent Nuna. Using their detrital-zircon age spectra, the three basins can be compared to similarly aged successions across Laurentia to further our understanding of how sediment dispersal networks distributed the products of orogenic unroofing across an accreting supercontinent. By these means, this thesis provides a wealth of new geochronologic data for the Precambrian of Laurentia, which serves to test novel basin-evolution histories and regional correlative stratigraphic frameworks.