Takahula Lake, Alaska 8,000 Year Stable Isotope Data Clegg, B.F.; Hu, F.S. Clegg, B.F. Hu, F.S. earth science/paleoclimate/instrumental (collection date,null,null,null,null,instrumental,null,null,C,null) earth science/paleoclimate/paleolimnology (age at sample end,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/instrumental (longitude,null,null,degree east,null,instrumental,null,null,N,null) earth science/paleoclimate/paleolimnology (depth at sample start,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/instrumental (delta 18O,lake water,null,per mil VSMOW,null,instrumental,null,isotope ratio mass spectrometry,N,null) earth science/paleoclimate/paleolimnology (delta 18O,carbonate,null,per mil VPDB,null,paleolimnology,null,isotope ratio mass spectrometry,N,charophyte encrustation) earth science/paleoclimate/paleolimnology (calcium carbonate,null,null,gram per square centimeter per year,null,paleolimnology,null,loss on ignition,N,loss on ignition 950 degrees) earth science/paleoclimate/paleolimnology (depth at sample end,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (age,null,null,year Common Era,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (delta 13C,carbonate,null,per mil VPDB,null,paleolimnology,null,isotope ratio mass spectrometry,N,charophyte encrustation) earth science/paleoclimate/paleolimnology (age at sample start,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/instrumental (delta 2H,lake water,null,per mil VSMOW,null,instrumental,null,isotope ratio mass spectrometry,N,null) earth science/paleoclimate/instrumental (air temperature,null,null,degree Fahrenheit,null,instrumental,null,null,N,null) earth science/paleoclimate/instrumental (lake surface temperature,null,null,degree Fahrenheit,null,instrumental,null,null,N,null) earth science/paleoclimate/instrumental (notes,null,null,null,null,instrumental,null,null,C,null) earth science/paleoclimate/instrumental (latitude,null,null,degree north,null,instrumental,null,null,N,null) earth science/paleoclimate/paleolimnology (Takahula Lake>LATITUDE 67.35>LONGITUDE -153.67) Understanding the ecological and socio-economic impacts of climatic warming requires knowledge of associated changes in moisture balance. Reconstructions of Holocene moisture-balance variation offer indispensible baseline information against which recent changes can be evaluated. In Alaska, little is known about variations in moisture balance during the middle- and late- Holocene. We analyzed Chara-stem encrustations in the sediments of Takahula Lake, south-central Brooks Range, for oxygen and carbon isotope composition to infer climatic change over the past 8000 years. To help constrain climatic interpretations of the sediment d18O record, we also analyzed water samples from Takahula and other lakes in the region for oxygen and hydrogen isotope composition. Results show that winter precipitation dominates the water balance of these lakes and that post-input evaporation is a key control of lake-water isotope composition of Takahula Lake. Stratigraphic patterns in Chara-d18O, supplemented by those in d13C and sediment lithology, reveal distinct changes in effective moisture (precipitation minus evaporation) over the past 8000 years. Effective moisture was relatively high from 8000 to 5000 cal. BP, with marked fluctuations between 6800 and 5000 cal. BP. It then decreased to reach a minimum around 4000 cal. BP and increased with fluctuations from 4000 to ~2500 cal. BP, followed by a decreasing trend toward the present that was interrupted by a wet Little Ice Age (centered at 400 cal. BP). Aridity during the 20th century was among the highest of the entire 8000-year record. The Chara-d18O values around 5600 cal. BP and around 400 cal. BP are up to 5ŋ lower than at present and ~2.3ŋ lower than that of the modern input water to the lake. These exceptionally low values suggest that factors other than effective moisture must have contributed to the pronounced variations in the Takahula Lake d18O record. These factors probably include increased winter precipitation related to the position and strength of the Aleutian Low, decreased temperatures, as well as increased lake-ice cover and associated reductions in evaporation. At millennial timescales, the temporal patterns of moisture-balance shifts at Takahula Lake are broadly coherent with those inferred from previous paleoclimate records from the region. STUDY NOTES: Centennial resolution isotope and geochemical data for Takahula Lake, Alaska, for the past 8000 years, plus surface lake-water isotope data from other Brooks Range lakes. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Clegg, B.F. Investigator : Hu, F.S. 2010-01-01 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/8663 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/takahula2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/takahula2010.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/takahula2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/takahula2010.xls English https://www.ncdc.noaa.gov/paleo/study/8663 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/takahula2010.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/takahula2010.xls Clegg, B.F., Hu, F.S. 2010. An oxygen-isotope record of Holocene climate change in the south-central Brooks Range, Alaska. Quaternary Science Reviews, 29, 928-939. START YEAR: 8057 cal yr BP * END YEAR: -52 cal yr BP -153.67 67.35 -153.67 67.35