1750 years of large rainfall events inferred from particle size at East Lake, Cape Bounty, Melville Island, Canada.

• Published in: Journal of Paleolimnology
• Main Authors: Lapointe, François, Francus, Pierre, Lamoureux, Scott F., Saïd, Mériem, Cuven, Stéphanie
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: 2012
• Subjects: Varves; Scanning electron microscope; Image analysis; Grain size; Paleoclimate; High-Arctic; Arctic; Canada; Cape Bounty; East Lake; Melville Island
• Online Access: https://espace.inrs.ca/id/eprint/10548/; https://doi.org/10.1007/s10933-012-9611-8

Annual grain-size variation was measured on the varved (annually laminated) lacustrine sediment from Cape Bounty East Lake using an innovative image analysis system. About 7100 images were acquired using a scanning electron microscope and processed to obtain measurement of particles from 2845 varves. Several particle-size distributions indices were calculated and can be linked to high-energy sedimentary facies. Moreover, the coarse grain size (98th percentile) of these high-energy facies is strongly correlated with summer rainfall (and also summer temperature) of instrumental data from nearby stations. Particle-size distributions show a similar trend through time, especially for the standard deviation and the 98th percentile. Climatic reconstruction suggests that Cape Bounty recently experienced an unprecedented increase of rainfall events since ~AD 1920. On the other hand, changes in varve thickness are weakly correlated with the particle-size distribution. Altogether, these results highlight the need to obtain annual grain-size data to identify a meteorological signal.