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

Lapointe, François; Francus, Pierre; Lamoureux, Scott F.; Saïd, Mériem; Cuven, Stéphanie (2012). 1750 years of large rainfall events inferred from particle size at East Lake, Cape Bounty, Melville Island, Canada. Journal of Paleolimnology , vol. 48 . p. 159-173. DOI: 10.1007/s10933-012-9611-8.

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Résumé

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.

Type de document: Article
Mots-clés libres: Varves; Scanning electron microscope; Image analysis; Grain size; Paleoclimate; High-Arctic
Centre: Centre Eau Terre Environnement
Date de dépôt: 19 nov. 2020 21:13
Dernière modification: 19 nov. 2020 21:13
URI: http://espace.inrs.ca/id/eprint/10548

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