CGRG Bibliography of Canadian Geomorphology
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Author : Francus, P.; Bradley, R.S.; and Abbott, M.B.
Date : 1999.
Title : Annually resolved past climate reconstruction from lacustrine varved sediments, Arctic, Canada.
Publication : 1999 Fall Meeting of the American Geophysical Union, December 13-17, 1999 , San Francisco, California (abstract).
Issue :
Page(s) :
Abstract
We intend to reconstruct and understand paleoclimate variability in the Canadian High Arctic using varved sediments from Sawtooth Lake (79ø 20' N, 83ø 51' W). Present day on-site meteorological, hydrological and sedimentological studies have been previously used to understand how the climatic signal is recorded in the varved sediments. The value of this has been demonstrated in our previous work, leading to more confidence in the underlying controls on sediment flux and varve formation in the lakes, linking meteorological data to varve thickness. Here, we present results obtained using an image analysis technique that provides multivariate quantified data for each varve. Backscattered electron microscope photographs of thin-sections are processed to produce black and white images, where white pixels represent the clay-rich sedimentary matrix and black pixels represent particles in the matrix: silt- or sand-sized, terrigenous or authigenic particles, diatoms or organic debris. Computer-assisted measurements of the size, shape, orientation and packing of the particles forming the varves allow their multivariate quantification. The data obtained on each single varve of the uppermost sections of the cores are then compared with meteorological and climatological data e.g. temperature, snow melt, wind, discharge. This comparison allows clarification of the climatic control on sediment fluxes to the lake and to build a model linking sediment to paleoclimate. This model will be used to infer paleoclimate with annual resolution for older period of time.
Bibliography of Canadian Geomorphology