Paleoclimate data from Melville Peninsula

Sediment cores were collected from two lakes in the vicinity of Sarcpa Lake (68.55 degN; -83.28 deg W), inland Melville Peninsula, for reconstructing Holocene paleoclimate. Proxy indicators were analyzed from each sites, including loss-on-ignition, magnetic susceptibility, biogenic silica, and pollen and diatom assemblages. Cores were dated using 210Pb and 14C; the chronologies confirm the retreat of glacial ice by 6000 yr BP. The proxies provide a ~6300 year record of post-glacial vegetation, limnological and climate change. Fossil pollen assemblages, pollen accumulations rates, and variations in sediment organic matter, indicate a period of regional Holocene warmth between 5300-3900 yr BP, followed by Neoglacial cooling, as well as a period of relative warmth between 1300-1000 yr BP, interpreted as evidence for the Medieval Warm Period. Diatom records corroborate warmer summers in the middle Holocene, and Neoglacial cooling. Variations in pollen abundances and accumulations during the 20th century, as well as novel diatom assemblages, suggest a response to anthropogenic warming that is unprecedented since deglaciation of the Peninsula. Comparisons of the timing and rates of multi-scale climate variations for Melville Peninsula with adjacent sites reveal a potential late Holocene shift in the boundary separating continental and maritime climate regions in the eastern Canadian Arctic.