Holocene sediment dynamics and environmental changes across the Canadian Arctic Archipelago

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Over recent decades, marine and terrestrial Arctic environments have responded strongly to modern climate warming. This response includes the reduction of summer ice thickness and extent, the increase in permafrost thaw and river runoff, the alteration of ice-drift paths, and sea-level rise, as well as a strong intensification of ice mass loss of the ice caps on the Canadian Arctic Archipelago (CAA). Another consequence of such warming is the alteration of sediment dynamics, which is characterized by distinct spatial differences. To place these environmental changes in a long-term historical perspective and to provide a basis for future Arctic climate simulations, one needs to better understand the natural evolution of marine CAA through the Late Quaternary. Thus, sedimentary sequences extending beyond instrumental records could provide a critical link for examining how different climate settings may influence both the sedimentary regimes and the Arctic marine ecosystems in the future. Sediments with different mineral assemblages and geochemical signatures are delivered into the CAA mainly as suspended particulate matter and bedloads from several river systems, iceberg rafting and sediment laden meltwater plumes from tidewater glaciers, as well as from coastal erosion, which is subsequently dispersed by ocean currents and sea-ice rafting. Consequently, the detrital signatures preserved in the CAA sedimentary records may be used to reconstruct past variations in sediment dynamics related to Late Quaternary climate changes. Under this context, the overall objective of this research program is to use a powerful multiproxy approach combining grain-size, mineralogy, elemental geochemistry, and radiogenic isotope compositions from a set of sediment samples recovered in the CAA, in order to unravel sediment sources and transport processes and to determine the pathways of possible chemical contaminants, glacier fluctuations and environmental changes during the Holocene (last 11,700 years). This innovative research program will offer a unique opportunity to improve the spatial and temporal resolution of sedimentological, mineralogical and geochemical data available in the CAA and will also help to unravel the fundamental processes controlling the Holocene sediment dynamics and environmental changes in this important polar region. A better understanding of the natural baseline of sedimentary regimes and their variability in the past can help Canada's government (e.g., Transport Canada and Environment and Climate Change Canada) to develop adaptation and mitigation strategies for possible contaminant dispersal, geohazards and the future navigability of Canadian Arctic sea routes. Finally, this research program will offer a dynamic training environment for highly qualified personnel with access to expertise in different fields of marine geology and geochemistry, as well as to hands-on training in Arctic ship-based coring and sampling operations.