Paleoclimate data from Melville Peninsula

• Main Authors: Finkelstein, Sarah, Adams, Jennifer K, John-Paul Iamonaco
• Format: Dataset
• Language: English
• Published: Canadian Cryospheric Information Network 2011
• Subjects: Algae; Hall Beach; Lake sediments; Melville Peninsula; Paleoclimatic reconstruction; Paleolimnology; Pollen; International Polar Year-Dynamic Inuit social strategies in changing environments a long term perspective; Arctic; Sarcpa Lake; Climate change; International Polar Year; inuit; Magnetic susceptibility
• Online Access: https://dx.doi.org/10.5443/10903; https://www.polardata.ca/pdcsearch/?doi_id=10903

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. : Purpose: Melville Peninsula is situated transitionally between two modern climate regimes and is an important region for archaeology of Thule sites. Thus, the goal of this project is to provide paleoenvironmental records for the periods preceding and during the Thule occupation. Paleoenvironmental indicators were selected to provide information on past temperatures, vegetation, seasonality, lake ice and aquatic ecosystems. : Summary: The sediment records obtained from two lakes on Melville Peninsula span the time period from about 6300 years ago to present day. These records were dated using radiocarbon dating, and confirm that glacial ice persisted on Melville Peninsula until about 6300 years ago. Several indicators were used to reconstruct past climates including the physical characteristics of the sediments, as well as biological remains of pollen grains and a group of algae (the diatoms). These indicators suggest that temperatures were warmer with longer growing seasons in the earlier part of the record, but after 3000 years ago, temperatures had cooled. The time period of Thule occupation is characterized by lower magnitude changes. Both the vegetation and aquatic indicators suggest large changes over the most recent century.