Loon Lake, Alaska 3000 Year Geochemical Data Chipman, M.L.; Hu, F.S. Chipman, M.L. Hu, F.S. earth science/paleoclimate/paleolimnology (age at sample end,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (depth at sample start,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/fire history|paleolimnology (charcoal,wet sediment,null,count,null,fire history|paleolimnology,null,null,N,> 120 um) earth science/paleoclimate/paleolimnology (volume magnetic susceptibility,sediment,null,dimensionless (SI system),null,paleolimnology,null,magnetic susceptibility measurement with single sample sensor,N,x10-6) earth science/paleoclimate/paleolimnology (strontium,sediment,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second) earth science/paleoclimate/paleolimnology (silicon,sediment,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second) earth science/paleoclimate/paleolimnology (calcium/strontium,sediment,null,dimensionless,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,ratio) earth science/paleoclimate/paleolimnology (iron,soil,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/fire history|paleolimnology (depth at sample start,null,null,centimeter,null,fire history|paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (calcium carbonate,sediment,null,percent,null,paleolimnology,null,loss on ignition,N,LOI at 950C x (100/44)) earth science/paleoclimate/paleolimnology (rubidium,soil,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/paleolimnology (silicon,soil,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/paleolimnology (calcium/strontium,soil,null,dimensionless,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/fire history|paleolimnology (depth at sample end,null,null,centimeter,null,fire history|paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (depth at sample end,null,null,centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (density,sediment,null,gram per cubic centimeter,null,paleolimnology,null,loss on ignition,N,Bulk Density LOI at 120C) earth science/paleoclimate/paleolimnology (mass magnetic susceptibility,sediment,null,cubic centimeter per gram,null,paleolimnology,null,magnetic susceptibility measurement with single sample sensor,N,null) earth science/paleoclimate/paleolimnology (iron,sediment,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second) earth science/paleoclimate/paleolimnology (sample identification,null,null,null,null,paleolimnology,null,null,C,Lake name) earth science/paleoclimate/paleolimnology (sample identification,null,null,null,null,paleolimnology,null,null,C,ID code for RTS feature) earth science/paleoclimate/fire history|paleolimnology (age at sample end,null,null,calendar year before present,null,fire history|paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (age at sample start,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (organic matter,sediment,null,percent,null,paleolimnology,null,loss on ignition,N,LOI at 550 C) earth science/paleoclimate/paleolimnology (rubidium,sediment,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second) earth science/paleoclimate/fire history|paleolimnology (age at sample start,null,null,calendar year before present,null,fire history|paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (potassium,sediment,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second) earth science/paleoclimate/paleolimnology (notes,null,null,null,null,paleolimnology,null,null,C,General sample location in RTS) earth science/paleoclimate/paleolimnology (notes,null,null,null,null,paleolimnology,null,null,C,Additonal sample description) earth science/paleoclimate/fire history|paleolimnology (volume,wet sediment,null,cubic centimeter,null,fire history|paleolimnology,null,null,N,used for charcoal counts) earth science/paleoclimate/paleolimnology (calcium,sediment,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second) earth science/paleoclimate/paleolimnology (titanium,sediment,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second) earth science/paleoclimate/paleolimnology (calcium/potassium,sediment,null,dimensionless,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,ratio) earth science/paleoclimate/paleolimnology (calcium,soil,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/paleolimnology (titanium,soil,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/paleolimnology (potassium,soil,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/paleolimnology (strontium,soil,null,count per second,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/paleolimnology (calcium/potassium,soil,null,dimensionless,null,paleolimnology,null,x-ray fluorescence spectroscopy,N,normalized counts per second; soil samples from shoreline retrogressive thaw slumps) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Loon Lake Alaska>LATITUDE 67.929269>LONGITUDE -161.966944) Amplified Arctic warming may facilitate novel tundra disturbance regimes, as suggested by recent increases in the rate and extent of thermoerosion and fires in some tundra areas. Thermoerosion and wildfire can exacerbate warming by releasing large permafrost carbon stocks, and interactions between disturbance regimes can lead to complex ecosystem feedbacks. We conducted geochemical and charcoal analyses of lake sediments from an Alaskan lake to identify thermoerosion and fire events over the past 3,000 years. Thermoerosion was inferred from lake sediments in the context of modern soil data from retrogressive thaw slumps (RTS). Magnetic susceptibility (MS), Ca:K, and Ca:Sr increased with depth in modern RTS soils and were higher on recently exposed than older slump surfaces. Peaks in bulk density, % CaCO3, Ca:K, Ca:Sr, and MS values in the sediments suggest at least 18 thermoerosion events in the Loon Lake watershed over the past 3,000 years. Charcoal analysis identifies 22 fires over the same period at this site. Temporal variability in these records suggests climate-driven responses of both thermoerosion and fire disturbance regimes, with fewer RTS episodes and fire events during the Little Ice Age than the Medieval Climate Anomaly. Moreover, RTS activity lagged behind catchment fires by 20-30 years (>90% confidence interval), implying that fires facilitated thermoerosion on decadal time scales, possibly because of prolonged active-layer deepening following fire and postfire proliferation of insulative shrub cover. These results highlight the potential for complex interactions between climate, vegetation, and tundra disturbance in response to ongoing warming. STUDY NOTES: Geochemical data from Loon Lake, Noatak National Preserve, Alaska. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Chipman, M.L. Investigator : Hu, F.S. 2018-01-04 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/23290 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018loi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018xrf.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018soilxrf.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018charcoal.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018ms.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018loi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018xrf.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018soilxrf.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018charcoal.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018ms.txt English https://www.ncdc.noaa.gov/paleo/study/23290 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018loi.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018xrf.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018soilxrf.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018charcoal.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/loon2018ms.txt Chipman, M.L. and Hu, F.S.2017Linkages Among Climate, Fire, and Thermoerosion in Alaskan Tundra Over the Past Three MillenniaJournal of Geophysical Research: Biogeosciences10.1002/2017JG004027http://onlinelibrary.wiley.com/doi/10.1002/2017JG004027/abstract START YEAR: 3003 cal yr BP * END YEAR: -64 cal yr BP -161.966944 67.929269 -161.966944 67.929269