Spatial and interannual variations in sedimentation patterns recorded in nonglacial varved sediments from the Canadian High Arctic

Multiple cores taken throughout Nicolay Lake in the Canadian High Arctic co ntain laminated sediments that are interpreted as varved. Annual sediment a ccumulation during the last 197 years reveals three major patterns that hav e important implications for hydroclimatic reconstruction. Widespread sedim ent dispersal is evident during most years and contrasts with years when an omalous localized and bifurcating patterns of deposition occur. Localized d eposition is limited to the centre of the lake and is attributed to turbidi ty currents that originate on the delta foreslope. In contrast, a bifurcati ng pattern is produced when the river supplying the delta switches from one to two delta distributaries, resulting in altered proximal accumulation. P rincipal component analysis reveals additional accumulation anomalies that are sedimentologically indistinct, but constitute important sources of loca lized variance. The recognition and removal of anomalous deposition pattern s is critical for accurate reconstruction of sediment flux from the catchme nt, particularly in long records where geomorphic conditions may have chang ed. This study identifies potentially misleading depositional artifacts and a methodology to recognize similar depositional controls in other lakes.