Early to mid-Holocene Atlantic water influx and deglacial meltwater events, Beaufort Sea Slope, Arctic Ocean

• Published in: Quaternary Research
• Main Authors: Andrews, John T., Dunhill, Gita
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2004
• Subjects: Arctic; Arctic Ocean; Mackenzie River; Glacial Lake; Beaufort Sea; Foraminifera*; Mackenzie river; Neogloboquadrina pachyderma; North Atlantic; Planktonic foraminifera
• Online Access: http://dx.doi.org/10.1016/j.yqres.2003.08.003; http://api.elsevier.com/content/article/PII:S0033589403001352?httpAccept=text/xml; http://api.elsevier.com/content/article/PII:S0033589403001352?httpAccept=text/plain; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0033589400012709

Holocene high-resolution cores from the margin of the Arctic Ocean are rare. Core P189AR-P45 collected in 405-m water depth on the Beaufort Sea slope, west of the Mackenzie River delta (70°33.03′N and 141°52.08′W), is in close vertical proximity to the present-day upper limit of modified Atlantic water. The 5.11-m core spans the interval between ∼6800 and 10,400 14 C yr B.P. (with an 800-yr ocean reservoir correction). The sediment is primarily silty clay with an average grain-size of 9 φ. The chronology is constrained by seven radiocarbon dates. The rate of sediment accumulation averaged 1.35 mm/yr. Stable isotopic data (δ 18 O and δ 13 C) were obtained on the polar planktonic foraminifera Neogloboquadrina pachyderma (s) and the benthic infaunal species Cassidulina neoteretis . A distinct low-δ 18 O event is captured in both the benthic and planktonic data at ∼10,000 14 C yr B.P.—probably recording the glacial Lake Agassiz outburst flood associated with the North Atlantic preboreal cold event. The benthic foraminifera are dominated in the earliest Holocene by C. neoteretis , a species associated with modified Atlantic water masses. This species decreases toward the core top with a marked environmental reversal occurring ∼7800 14 C yr B.P. possibly coincident with the northern hemisphere 8200 cal yr B.P. cold event.