DROUGHT HISTORY OF SCOUT LAKE, SOUTHWESTERN YUKON TERRITORY, CANADA BASED ON STABLE ISOTOPE MEASUREMENTS

Here we present a 4,000-year history of drought from a small (<1 km2), shallow (7-m deep) closed basin lake in the southwestern Yukon Territory, Canada. Scout Lake contains 2-m of finely laminated sediment containing authigenic calcium carbonate representing the past 4,000 yr. The chronology is based on radiocarbon dates on terrestrial macrofossils and charcoal. This isolated lake basin is fed by a small catchment and is largely free of groundwater influence. The modern surface waters are enriched in D and 18O with respect to spring waters sampled in the watershed and the regional meteoric waterline suggesting that the lake is evaporatively enriched. Using isotope records from hydrologically-open lake systems in the area we reconstruct the timing, duration and frequency of droughts in this region.