Seven Mile Lake, Yukon 1000 Year Oxygen Isotope Data Anderson, L.; Finney, B.P.; Shapley, M.D. Anderson, L. Finney, B.P. Shapley, M.D. Little Ice Age (LIA) hydrology earth science/paleoclimate/paleolimnology (depth,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (delta 18O,carbonate,null,per mil VPDB,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (Seven Mile Lake>LATITUDE 62.17916>LONGITUDE -136.38323) A 1000-yr history of climate change in the central Yukon Territory, Canada, is inferred from sediment composition and isotope geochemistry from small, groundwater fed, Seven Mile Lake. Recent observations of lake-water d18O, lake level, river discharge, and climate variations, suggest that changes in regional effective moisture (precipitation minus evaporation) are reflected by the lake's hydrologic balance. The observations indicate that the lake is currently 18O-enriched by summer evaporation and that during years of increased precipitation, when groundwater inflow rates to the lake increase, lakewater d18O values decrease. Past lake-water d18O values are inferred from oxygen isotope ratios of fine-grained sedimentary endogenic carbonate. Variations in carbonate d18O, supplemented by those in carbonate and organic d13C, C/N ratios, and organic carbon, carbonate and biogenic silica accumulation rates, document changes in effective moisture at decadal time scales during the early Little Ice Age period to present. Results indicate that between ~AD 1000 and 1600, effective moisture was higher than today. A shift to more arid climate conditions occurred after ~AD 1650. The 19th and 20th centuries have been the driest of the past millennium. Temporal variations correspond with inferred shifts in summer evaporation from Marcella Lake d18O, a similarly small, stratified, alkaline lake located ~250 km to the southwest, suggesting that the combined reconstructions accurately document the regional paleoclimate of the east-central interior. Comparison with regional glacial activity suggests differing regional moisture patterns during early and late Little Ice Age advances. STUDY NOTES: High resolution sediment d18O data from Seven Mile Lake, Yukon covering the last 1000 years. Carbonate d18O ratios of 32um bulk sediment size fraction from continuous intervals of 0.5 cm from 0 to 55.5 cm depth. Intervals of low percent carbonate (and corresponding isotope data gaps) are interpreted as dry periods. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Anderson, L. Investigator : Finney, B.P. Investigator : Shapley, M.D. 2011-04-06 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/10750 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/yukon/seven-mile2011.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/yukon/seven-mile2011.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/yukon/seven-mile2011.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/yukon/seven-mile2011.txt English https://www.ncdc.noaa.gov/paleo/study/10750 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/yukon/seven-mile2011.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/canada/yukon/seven-mile2011.txt Anderson, L., B.P. Finney, and M.D. Shapley. 2011. Lake carbonate d18O records from the Yukon Territory, Canada: Little Ice Age moisture variability and patterns. Quaternary Science Reviews, Vol. 30, Issues 7-8, April 2011, pp. 887-898. doi:10.1016/j.quascirev.2011.01.005 START YEAR: 962 cal yr BP * END YEAR: -49 cal yr BP -136.38323 62.17916 -136.38323 62.17916