TEMPERATURE CHANGES DURING THE LAST GLACIAL-INTERGLACIAL TRANSITION BASED ON OXYGEN ISOTOPE ANALYSES OF AUTHIGENIC LAKE CARBONATES FROM SPIRIT LAKE IN THE SOUTHERN YUKON TERRITORY

High-resolution paleoclimate records from subarctic sites provide valuable insight into global climate because the amplitude of temperature variations is greater than at lower latitudes. Oxygen isotope analysis of lake carbonates have been shown to be particularly useful in this regard owing to their sensitivity to both temperature and precipitation changes. Previous lake carbonate records from the Yukon Territory region exist, however, due to extensive ice cover associated with the Late Wisconsinan McConnell glaciation there are few lake records that extend back past 12,000 years. In this study we present an oxygen isotope record from an 11 meter core of authigenic lake carbonates in a subarctic lake which extends back past the Pleistocene-Holocene transition. Variations in the oxygen isotope composition of Spirit Lake carbonates are broadly correlated with ice core isotope records from both Canada and Greenland, suggesting that these lake carbonates are accurately recording regional climatic conditions. Results indicate that the southern Yukon Territory experienced a ~8-10°C temperature change during the last glacial-interglacial transition with the warmest Holocene temperatures occurring immediately following this transition. Several large amplitude temperature shifts are associated with this transition and are likely related to the Bølling-Allerød and Younger Dryas climate events. A high sedimentation rate throughout this period documents climate at a higher resolution than other climate proxies, resolving higher frequency climate signals. Thus a better understanding of climate dynamics during this transitional period is achieved. The oxygen isotope record from Spirit Lake carbonates represents an ideal proxy to enhance the climatic record of this subarctic region at a higher resolution than previously documented.