HR: 14:45h
AN: C13C-05    [Abstracts]
TI: An annually resolved 2500 yr long record of rain events in a polar desert
AU: * Francus, P
EM: pierre_francus@inrs-ete.uquebec.ca
AF: Institut national de la recherche scientifique, Centre Eau, Terre et Environnement 490 de la couronne, Qu‚bec, QC G1K 9A9 Canada
AU: * Francus, P
EM: pierre_francus@inrs-ete.uquebec.ca
AF: University of Massachusetts, Amherst, Dept. of Geosciences, Climate System Research Center 611 North Pleasant street, Amherst, MA 01003-9297 United States
AU: Bradley, R S
EM: rbradley@geo.umass.edu
AF: University of Massachusetts, Amherst, Dept. of Geosciences, Climate System Research Center 611 North Pleasant street, Amherst, MA 01003-9297 United States
AB: Varved sediments of Sawtooth lake, Nunavut Canada contain a ~2500 years long record of past environments. Sediment accumulation is mainly due to spring snowmelt that forms silty laminations grading into clay. However, coarser non-erosive sand beds frequently interrupt this regular sedimentation. Field observation and evidences from the analysis of the sediment, mainly from thin-sections, point out that these coarse beds are due to summer rain events. Results from the analysis of the occurrence of these events are presented. We investigate both short (interannual) and long (centennial) scale variability. We also investigate the possibility of geomorphic influences on the delivery of sediment to the lake basin. Our preliminary data reveal that the so-called medieval period might have been characterized by rainy summers in this part of the Arctic.
DE: 3344 Paleoclimatology
DE: 1815 Erosion and sedimentation
DE: 1845 Limnology
DE: 1894 Instruments and techniques
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting