Late Holocene Paleoclimate Reconstruction in Debauchery Bay, Northwest Territories Canada using Particle Size Analysis and Geochemical Proxies

Climate variability significantly influences lacustrine systems, impacting physical, chemical, and biological components.This is particularly true of lakes situated in high-latitude northern environments, where the impact of a changing climate is particularly pronounced.Of additional concern in the Yellowknife, Northwest Territories area is the widespread contamination by arsenic associated with ore processing at the former Giant Mine, located just north of the community.In this study, high-resolution ITRAX X-ray Fluorescence (XRF) and particle size data obtained from a freeze core recovered from Debauchery Bay in Walsh Lake were analyzed to infer and quantify late Holocene changes within this lake system and their implications for the mobility and fate of arsenic in surface water environments.Through examination of proxy data preserved in an ~ 1000 -year freeze core, results suggest that arsenic sequestration in sediments has been linked with the presence of Fe(oxy) hydroxides in oxygenated shallow sedimentary environments.Climate variability associated with the Medieval Climate Anomaly and subsequent cooling associated with the Little Ice Age impacted sediment geochemistry, demonstrating climate controls on mobility and sequestration of trace metals in high-latitude lacustrine environments.In addition, significant periodicities of 5-8,11-14, 60, 100 -113, and 202 yr periods were observed in spectral and wavelet time series analysis results based on selected XRF elemental and robust End Member Mixing Analysis records.These frequencies are interpreted as corresponding to the combined impact of the North Atlantic Oscillation and Schwabe sunspot cycles, 30 -60 -yr Pacific Decadal Oscillation, 90-yr Gleissberg cycle and 205-yr Suess cycle.