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

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 (70degrees33.03' N and 141degrees52.08' 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 similar to 6800 and 10,400 C-14 yr B.P. (with an 800-yr ocean reservoir correction). The sediment is primarily silty clay with an average grain-size of 9 phi. The chronology is constrained by seven radiocarbon dates. The rate of sediment accumulation averaged 1.35 mm/yr. Stable isotopic data (delta(18)O and delta(13)C) were obtained on the polar planktonic foraminifera Neogloboquadrina pachyderma (s) and the benthic infaunal species Cassidulina neoteretis. A distinct low-delta(18)O event is captured in both the benthic and planktonic data at similar to 10,000 C-14 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 similar to 7800 C-14 yr B.P., possibly coincident with the northern hemisphere 8200 cal yr B.P. cold event. (C) 2003 University of Washington. All rights reserved.