Holocene paleoclimate reconstruction from delta-oxygen-18 cellulose and response to solar forcing in eastern Canada: Evidence from Mer Bleue Bog, Ottawa, Ontario

This study is aimed to reconstruct the Holocene temperature history in eastern Canada derived from a 6m peat section at Mer Bleue Bog, near Ottawa, Ontario.;The results demonstrate that the delta18Ocel of Sphagnum can provide a reliable paleotemperature proxy in continental settings (e.g., Ottawa, Ontario). delta18O cel based paleotemperature reconstructions must take into account significant stable oxygen isotopic differences between cellulose from Sphagnum and other peatland plant macrofossils, whereas the offsets between delta 18Ocel of different Sphagnum species are statistically insignificant.;The delta18Ocel record obtained from the Mer Bleue Bog core correlates well with the instrumental temperature record, northern Hemisphere paleotemperature reconstructions and reconstructed solar activity records.;At the Mer Bleue Bog, solar activity fluctuations at the ∼80-year to 2500-year cycle bands recorded in peat color and X-ray density, and delta 18Ocel data appear to have a major influence on regional and global climate as are recorded in peat color and X-ray density, and isotope data throughout the Holocene. In particular the results suggest that 180-250 years "Suess" and ∼1300 years "Bond" cycles controlled long-term variability in temperature and peat sedimentation in eastern Canada. The Mer Bleue Bog delta18Ocel data correlate well with Atlantic ice-rafted debris, and European climate features such as the Little Ice Age and the Medieval Warm period, as well as pronounced northern Hemisphere cooling that is likely triggered by the Dalton solar minima from ∼1810-1820 A.D. and amplified by the Mount Tambora, Indonesia eruption of 1815.;Geochemical, image and time-series analysis methods such as oxygen isotope analysis of plant cellulose (delta18Ocel), digital peat sediment photographs and X-ray scans, have been used to extract high-resolution paleotemperature proxy records and to detect cycles and trends, which were compared with the instrumental temperature record, solar activity proxies, and northern Hemisphere paleoclimate reconstructions. A 30 cm peat section from Glen West Bog, Northern Ireland, spanning 2880 to 2500 cal. yr. B.P., was studied to test the validity of the methods and results for maritime climate settings.;Solar activity fluctuations at the ∼11-year and ∼250-year cycle-band in a ∼380 year record have a major influence on the North Atlantic climate as is recorded in sediment imaging and delta18Ocel data from Northern Ireland.