Carleton Lake, Northwest Territories 6000yr Chironomid-inferred Temperature Upiter, L.M.; Vermaire, J.C.; Patterson, R.T.; Crann, C.A.; Galloway, J.M.; Macumber, A.L.; Neville, L.A.; Swindles, G.T.; Falck, H.; Roe, H.M.; Pisaric, M. Upiter, L.M. Vermaire, J.C. Patterson, R.T. Crann, C.A. Galloway, J.M. Macumber, A.L. Neville, L.A. Swindles, G.T. Falck, H. Roe, H.M. Pisaric, M. Air Temperature Reconstruction Arctic earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface temperature,midge assemblage,unspecified margin of error,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,null,N,based on Porinchu et al (2009) transfer function) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface temperature,midge assemblage,unspecified margin of error,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,null,N,based on Barley et al (2006) transfer function) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (depth,null,null,centimeter,null,climate reconstructions|insect|paleolimnology,null,null,N,null) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,null,N,based on Porinchu et al (2009) transfer function) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (surface temperature,midge assemblage,null,degree Celsius,Jul,climate reconstructions|insect|paleolimnology,null,null,N,based on Barley et al (2006) transfer function) earth science/paleoclimate/climate reconstructions|insect|paleolimnology (age,null,null,calendar year before present,null,climate reconstructions|insect|paleolimnology,null,null,N,present defined as 2010 AD) earth science/paleoclimate/reconstructions (Carleton Lake>LATITUDE 64.2572>LONGITUDE -110.1008) We analyzed subfossil chironomids, sediment organic matter and sediment particle size data from a 1.11-m-long freeze core collected from Carleton Lake (unofficial name), located approximately 120 km north of the modern treeline. This well-dated core spans the last ca. 6,500 years. Two chironomid transfer functions were applied to infer mean July air temperatures. Our results indicated that the chironomid-inferred temperatures from this lake sediment record did not pass a significance test, suggesting that other factors in addition to temperature may have been important in structuring the chironomid community through time. Although not statistically significant, the chironomid-inferred temperatures from this site do follow a familiar pattern, with highest inferred temperatures occurring during the Holocene Thermal Maximum (~6-4 cal kyr BP), followed by a long-term cooling trend, which is reversed during the last 600 years. The largest change in the chironomid assemblage, which occurred between ca. 4,600 and 3,900 cal yr BP is possibly related to the well-documented northward advance and subsequent retreat of treeline in this region. STUDY NOTES: Fossil midges were processed following methods given in Walker (2001). Mean July air temperatures were estimated using two separate transfer function models developed by Barley et al. (2006) and Porinchu et al. (2009). NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Upiter, L.M. Investigator : Vermaire, J.C. Investigator : Patterson, R.T. Investigator : Crann, C.A. Investigator : Galloway, J.M. Investigator : Macumber, A.L. Investigator : Neville, L.A. Investigator : Swindles, G.T. Investigator : Falck, H. Investigator : Roe, H.M. Investigator : Pisaric, M. 2014-04-08 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/16296 https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/canada/nwt/carleton2014cit.txt https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/canada/nwt/carleton2014cit.txt English https://www.ncdc.noaa.gov/paleo/study/16296 https://www1.ncdc.noaa.gov/pub/data/paleo/insecta/chironomidae/northamerica/canada/nwt/carleton2014cit.txt Lindsay M. Upiter, Jesse C. Vermaire, R. Timothy Patterson, Carley A. Crann, Jennifer M. Galloway, Andrew L. Macumber, Lisa A. Neville, Graeme T. Swindles, Hendrik Falck, Helen M. Roe, Michael F. J. Pisaric2014Middle to late Holocene chironomid-inferred July temperatures for the central Northwest Territories, CanadaJournal of Paleolimnology10.1007/s10933-014-9775-5http://link.springer.com/article/10.1007/s10933-014-9775-5 Erin M. Barley, Ian R. Walker, Joshua Kurek, Les C. Cwynar, Rolf W. Mathewes, Konrad Gajewski, Bruce P. Finney 2006A northwest North American training set: distribution of freshwater midges in relation to air temperature and lake depthJournal of Paleolimnology363295-31410.1007/s10933-006-0014-6http://link.springer.com/article/10.1007/s10933-006-0014-6 David Porinchu, Nicolas Rolland, Katrina Moser2009Development of a chironomid-based air temperature inference model for the central Canadian ArcticJournal of Paleolimnology412349-36810.1007/s10933-008-9233-3http://link.springer.com/article/10.1007/s10933-008-9233-3 START YEAR: 5964 cal yr BP * END YEAR: -54 cal yr BP -110.1008 64.2572 -110.1008 64.2572