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

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...

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Bibliographic Details
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
Description
Summary: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.

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