INFERRING PAST CLIMATIC CHANGES IN CANADA USING PALEOLIMNOLOGICAL TECHNIQUES

Paleolimnological approaches have considerable potential for providing paleoclimate proxy data. Indicators such as diatom valves, chrysophyt e scales and cysts, and chironomid head capsules may provide both dire ct and indirect inferences of lakewater temperature and related variab les. For example, quantitative transfer functions are now available fo r certain regions that can infer lakewater temperature from chironomid s and diatoms. Meanwhile, the paleolimnological record from closed-bas in lakes in arid and semi-arid regions of western Canada can be used t o track past climatic/hydrologic changes, as transfer functions have b een developed for diatom, chrysophyte and chironomid indicators that c an provide quantitative inferences of past lakewater salinity. Other c limate-related variables that can be tracked include dissolved organic carbon concentrations that can be related to past changes in arctic t reeline, and past ice-cover in high-arctic regions.