CGRG Bibliography of Canadian Geomorphology
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Author : Gilbert, R.; and Lamoureux, S.
Date : 2001.
Title : Sedimentary record of lakes across the northern Coast Mountains in response to spatial and temporal climatic influence.
Publication : Canadian Quaternary Association/ Association canadienne pour l'etude du Quaternaire, Annual Meeting 2001. Whitehorse, Yukon Territory, August 20 – 24, 2001.
Issue :
Page(s) :
Abstract
With the growing recognition of short-term fluctuations in climate driven by decadal oceanic oscillations, it is increasingly important to use long-term proxy data to assess changes beyond the instrumental record and to understand the response of the hydrologic, glacial and geomorphic systems to past and future climate forcing, including human-induced global warming. In this preliminary study of lakes across the Coast Mountains in Northern British Columbia, Yukon and southeastern Alaska, we set the stage for in-depth study of drainage basin and lacustrine processes, and application of lacustrine records to assessment of environmental change in the region. We have measured limnological data and collected surface sediment cores from Atlin Lake (including Torres Channel, Williston Bay and Llewellyn Inlet), Bennett Lake, and Chilkoot Lake. These three sites represent a transect from continental to maritime climate influence, with varying impact of glacial and hydrologic inputs. Our sampling was carried out in late July-early August 1999 during a period of high temperatures. All three lakes are thermally stratified and exhibit evidence of sediment transport via interflows and underflows. Subbottom sounding indicated varying sediment fills, but sites with high sediment influx (Chilkoot, Williston Bay, Llewellyn Inlet) showed evidence for substantial accumulation. Sediments from all sites were laminated and thin section analysis suggests that Chilkoot and the proximal sites in Atlin Lake are varved. These catchments derive most of their incoming sediment from glacial meltwater. In contrast, Bennett Lake showed decreased suspended sediment in the water column and faintly laminated sediments in the south arm, likely due to upstream sediment traps. In addition to these preliminary results, we plan to carry out detailed subbottom acoustic surveys, sediment coring, and lacustrine process studies to identify the nature of the environmental signal contained in the sediments.
Bibliography of Canadian Geomorphology