West Greenland Holocene Lake Sediment Data Axford, Y.; Losee, S.; Briner, J.P.; Francis, D.R.; Langdon, P.G.; Walker, I.R. Axford, Y. Losee, S. Briner, J.P. Francis, D.R. Langdon, P.G. Walker, I.R. earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,calibration data set: Eastern Canada Francis et al. 2006 and Eastern Canada Walker et al. 1997;reconstruction technique: Weighted averaging regression with tolerance downweighting) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Tanytarsus sp. no spur) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Micropsectra sp.) earth science/paleoclimate/paleolimnology (organic matter,sediment,null,weight percent,null,paleolimnology,null,loss on ignition,N,loss on ignition 550 degrees C for 2 hours) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Psectrocladius sordidellus) earth science/paleoclimate/insect|paleolimnology (age,null,null,calendar year before present,null,insect|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,weighted-averaging regression) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Paracladopelma sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Procladius sp.) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,anomalized,regression analysis,N,anomalized from modern; calibration data set: Eastern Canada Francis et al. 2006 and Eastern Canada Walker et al. 1997; weighted averaging regression with tolerance downweighting) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,calibration data set: Eastern Canada Francis et al. 2006 and Walker et al. 1997; weighted-averaging regression) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,calibration data set: Eastern Canada Francis et al. 2006 and Walker et al. 1997; Weighted averaging regression with tolerance downweighting) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Tanytarsini) earth science/paleoclimate/paleolimnology (biogenic silica,dry sediment,null,weight percent,null,paleolimnology,null,spectrophotometry,N,method of Mortlock and Froelich 1989 with 10% Na2CO3) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Chironomus larvula) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,regression analysis,N,calibration data set: Iceland Langdon et al. 2008; weighted-averaging partial least-squares regression) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,anomalized|averaged,null,N,"anomalized from modern, average of multiple reconstructions") earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Chironomus sp.) earth science/paleoclimate/paleolimnology (volume magnetic susceptibility,sediment,null,dimensionless (CGS system),null,paleolimnology,null,magnetic susceptibility measurement with point or surface sensor,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (age,null,null,calendar year before present,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Ablabesmyia sp.) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,anomalized,regression analysis,N,anomalized from modern; calibration data set: Eastern Canada Francis et al. 2006 and Eastern Canada Walker et al. 1997; weighted averaging regression) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface air temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,anomalized,regression analysis,N,anomalized from modern; calibration data set: Iceland Langdon et al. 2008; weighted averaging partial least-squares regression) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Orthocladiinae) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Dicrotendipes sp.) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Tanytarsus lugens type) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Corynoneura arctica) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,dimensionless,null,insect|paleolimnology,null,null,N,Oliveridia/Hydrobaenus) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Cricotopus sp. type P) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Arctopelopia sp.) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,dimensionless,null,insect|paleolimnology,null,null,N,Cricotopus/Orthocladius) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Heterotrissocladius grimshawi) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Tanypodinae) earth science/paleoclimate/insect|paleolimnology (identified midge,null,null,percent,null,insect|paleolimnology,null,null,N,Metriocnemus hygropetricus) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (North Lake>LATITUDE 69.2416>LONGITUDE -50.0272) (Pluto Lake>LATITUDE 69.1087>LONGITUDE -51.0305) (Iceboom Lake>LATITUDE 69.23535>LONGITUDE -50.0159) (Loon Lake GND>LATITUDE 69.05815>LONGITUDE -49.91605) (Fishtote Lake>LATITUDE 69.2281>LONGITUDE -50.9267) Predicting the response of the Greenland Ice Sheet to future climate change presents a major challenge to climate science. Paleoclimate data from Greenland can provide empirical constraints on past cryospheric responses to climate change, complementing insights from contemporary observations and from modeling. Here we examine sedimentary records from five lakes near Jakobshavn Isbrae in central West Greenland to investigate the timing and magnitude of major Holocene climate changes, for comparison with glacial geologic reconstructions from the region. A primary objective of this study is to constrain the timing and magnitude of maximum warmth during the early to middle Holocene positive anomaly in summer insolation. Temperature reconstructions from subfossil insect (chironomid) assemblages suggest that summer temperatures were warmer than present by at least 7.1 ka (the beginning of the North Lake record; ka = thousands of years before present), and that the warmest millennia of the Holocene occurred in the study area between 6 and 4 ka. Previous studies in the Jakobshavn region have found that the local Greenland Ice Sheet margin was most retracted behind its present position between 6 and 5 ka, and here we use chironomids to estimate that local summer temperatures were 2-3°C warmer than present during that time of minimum ice sheet extent. As summer insolation declined through the late Holocene, summer temperatures cooled and the local ice sheet margin expanded. Gradual, insolation-driven millennial-scale temperature trends in the study area were punctuated by several abrupt climate changes, including a major transient event recorded in all five lakes between 4.3 and 3.2 ka, which overlaps in timing with abrupt climate changes previously documented around the North Atlantic region and farther afield at ~4.2 ka. STUDY NOTES: Lake sediment proxy data from 5 Holocene lakes in West Greenland, located between Disko Bugt and the Greenland Ice Sheet near the coastal town of Ilulissat. Proxy data include Magnetic Susceptibility (MS), Loss-on-Ignition (LOI), Biogenic Silica, and chironomid assembledges. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Axford, Y. Investigator : Losee, S. Investigator : Briner, J.P. Investigator : Francis, D.R. Investigator : Langdon, P.G. Investigator : Walker, I.R. 2012-12-13 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/13664 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/loon2013.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013chiro.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/fishtote2013chiro.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/iceboom2013.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/fishtote2013loims.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013biosi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013loi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/pluto2013.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/loon2013.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013chiro.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/fishtote2013chiro.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/iceboom2013.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/fishtote2013loims.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013biosi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013loi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/pluto2013.txt English https://www.ncdc.noaa.gov/paleo/study/13664 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/loon2013.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013chiro.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/fishtote2013chiro.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/iceboom2013.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/fishtote2013loims.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013biosi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/north2013loi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/greenland/pluto2013.txt Yarrow Axford, Shanna Losee, Jason P. Briner, Donna R. Francis, Peter G. Langdon, and Ian R. Walker. 2013. Holocene temperature history at the western Greenland Ice Sheet margin reconstructed from lake sediments. Quaternary Science Reviews, Vol. 59, pp. 87-100, 3 January 2013. DOI: 10.1016/j.quascirev.2012.10.024 START YEAR: 10334 cal yr BP * END YEAR: -59 cal yr BP -51.0305 69.05815 -49.91605 69.2416