The deglacial to postglacial marine environments of SE Barrow Strait, Canadian Arctic Archipelago

• Published in: Boreas
• Main Authors: Pieńkowski, Anna J., England, John H., Furze, Mark F.A., Marret, Fabienne, Eynaud, Frédérique, Vilks, Gustav, Maclean, Brian, Blasco, Steve, Scourse, James D.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2011
• Subjects: Arctic; Barrow Strait; Canadian Arctic Archipelago; Arctic Archipelago; Foraminifera*; Ice Sheet; Planktonic foraminifera; Sea ice
• Online Access: http://dx.doi.org/10.1111/j.1502-3885.2011.00227.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1502-3885.2011.00227.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1502-3885.2011.00227.x

Core 86027‐144 (74°15.56′ N , 91°14.21′ W ) represents a rare, continuous record of L ate P leistocene to H olocene sediments from H igh A rctic C anada extending from the end of the L ast G laciation. Based on microfossils (dinocysts, non‐pollen palynomorphs, benthic and planktonic foraminifera), foraminiferal δ 18 O and δ 13 C , and sedimentology, seven palaeoenvironmental zones were identified. Zone I (>10.8 cal. ka BP ) records deglaciation, ice‐sheet destabilization, float‐off and subsequent break‐up. Zone II ( c. 10.8–10.4 cal. ka BP ) shows ice‐proximal to ice‐distal glaciomarine conditions, interrupted by pervasive land‐fast sea‐ice marked by a hiatus in coarse sediment deposition. Significant biological activity starts in Zone III (10.4–9.9 cal. ka BP ), where planktonic foraminifera ( N eogloboquadrina pachyderma ) suggest early oceanic throughflow. Surface waters flowed NW–SE however, the deep‐water origin remains unclear (potentially NW A rctic O cean or B affin B ay). Postglacial amelioration (open‐water season greater than present) in Zone IV (9.9–7.8 cal. ka BP ) perhaps corresponds to the regional ‘Holocene Thermal Maximum’ previously proposed. A transitional period (Zone V 7.8–6.7 cal. ka BP ) of rapid environmental change fluctuating on a scale not observed today is marked by increasing sea‐ice and reduced oceanic influence. This probably signals the exclusion of deeper A tlantic water owing to the glacio‐isostatic shallowing of inter‐island sills, coupled with generally cooling climate. Conditions analogous to those at present, with increased sea‐ice and modern microfossil assemblages, commence at c. 6.7 cal. ka BP (zones VI – VII ). Although climate ultimately forces long‐term environmental trends, core 86027‐144 data imply that regional dynamics, especially changes in sea‐level, exert a significant control on marine conditions throughout the C anadian A rctic A rchipelago.