Summary: Two lake-sediment cores from the western and central Canadian Arctic
were used to investigate late Holocene climate variability in the region.
Both cores were analyzed for pollen, organic matter, biogenic silica,
and magnetic susceptibility, and were dated using a combination of 210Pb
and 14C techniques. Core MB01, from southwestern Victoria Island,
provides a 2600-year-long record. Fossil pollen percentages, along with
other parameters, suggest the occurrence of a cold period around
2400 cal year BP (450 BC), followed by slightly warmer conditions
by 1800 cal year BP (150 AD), and a return to cooler conditions throughout
much of the last millennium. Core SL06, from southern Boothia Peninsula,
shows more subtle changes in pollen percentages over its 2500-year duration,
but an increase in Cyperaceae and decrease in Oxyria pollen around 1400
cal year BP (550 AD) are indicative of warmer conditions at that time.
Quantitative climate reconstructions from these pollen sequences were
compared to two other pollen-based climate records from the region
and indicate the presence of a widespread wet period ~1500 cal year BP
(450 AD), and a cool and dry Little Ice Age. In the reconstructions
based on pollen percentage data, the twentieth century summer temperature
and annual precipitation in the central and western Canadian Arctic were
comparable to that which occurred over the last 2500 years. However,
pollen-influx values increase in the most recent sediments, suggesting
high plant productivity during the late twentieth century.
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