| Abstract | A marine sediment core from the east-central Canadian Arctic Archipelago (Core 86027-154; 74¡ 22.01'N 89¡ 51.26'W; 329m water depth), studied by a multiproxy approach [lithostratigraphy,
biogeochemistry, micropalaeontology (dinoflagellate cysts, other non-pollen palynomorphs, benthic and planktonic foraminifera, ostracods)], and encompassing 14 AMS 14C dates, provides valuable insights into regional deglacial to Holocene
palaeoenvironments. Six palaeoenvironmental zones are recognized, based on prominent changes in the litho- and biostratigraphy. The waterlain diamicton of Zone I records immediate deglaciation, being derived from lift-off and calving of previously
grounded glacial ice. Though deglacial timing is complicated by the sparsity of dating materials and the Portlandia Effect, age-depth model extrapolation places deglaciation at 11.54calkaBP. Zone II (11.5-11.0calkaBP) represents a distinct
progression from initially ice-proximal to increasingly ice-distal conditions, interrupted by an intervalofpervasive sea-ice (11.4-11.2calkaBP). Noteworthy biological activity commences in Zone III (11.0-9.7calkaBP) with a prominent signal of
planktonic foraminifera (Neogloboquadrina pachyderma). This likely signifies penetration of deeper, Atlantic-derived water through the central Canadian Arctic Archipelago upon deglaciation, facilitated by the greater, glacioisostatically-induced
water depths(+80m), and implies separation of Laurentide and Innuitian ice sheets by ~11.0calkaBP. Zone IV(9.7-7.2calkaBP) records ameliorated, biologically favourable conditions with reduced seasonalsea-iceaccompanied by high microfossil species
diversity and the presence of subpolar taxa. Zone V (7.2-6.5calkaBP) signals the exclusion of Atlantic-derived water, concomitant with increasing sea-ice, simultaneously representing the termination of the dynamic deglacial to early Holocene
environments (zones I-IV). Conditions similar to modern typified by uniform sediment characteristics, present-day microfossil assemblage structures, and sparse benthic foraminifera were established by 5.6calkaBP (Zone VI). |