Kepler Lake, Alaska 800 Year Multiproxy Sediment Data Gonyo, A.W.; Yu, Z.; Bebout, G.E. Gonyo, A.W. Yu, Z. Bebout, G.E. Arctic Little Ice Age (LIA) PAGES Arctic 2k earth science/paleoclimate/paleolimnology (calcium carbonate,sediment,null,weight percent,null,paleolimnology,null,loss on ignition,N,null) earth science/paleoclimate/paleolimnology (carbon/nitrogen,sediment,null,dimensionless,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (organic matter,sediment,null,weight percent,null,paleolimnology,null,loss on ignition,N,null) earth science/paleoclimate/paleolimnology (density,sediment,null,gram per cubic centimeter,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (delta 15N,organic matter,null,per mil AIR,null,paleolimnology,null,isotope ratio mass spectrometry,N,null) 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 18O,carbonate,null,per mil VPDB,null,paleolimnology,null,isotope ratio mass spectrometry,N,calcite) earth science/paleoclimate/paleolimnology (delta 13C,organic matter,null,per mil VPDB,null,paleolimnology,null,isotope ratio mass spectrometry,N,null) earth science/paleoclimate/paleolimnology (delta 13C,carbonate,null,per mil VPDB,null,paleolimnology,null,isotope ratio mass spectrometry,N,calcite) earth science/paleoclimate/paleolimnology (mineral matter,sediment,null,weight percent,null,paleolimnology,null,loss on ignition,N,null) earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology earth science/paleoclimate/paleolimnology (Kepler Lake>LATITUDE 61.5544>LONGITUDE -149.2119) Climate records during the last millennium are essential in placing recent anthropogenic-induced climate change into the context of natural climatic variability. However, detailed records are still sparse in Alaska, and these records would help elucidate climate patterns and possible forcing mechanisms. Here we present a multiple-proxy sedimentary record from Kepler Lake in south-central Alaska to reconstruct climatic and environmental changes over the last 800 years. Two short cores (85 and 101 cm long) from this groundwater-fed marl lake provide a detailed stable isotope and sediment lithological record with chronology based on four AMS 14C dates on terrestrial macrofossils and 210Pb analysis. The d18O values of inorganic calcite (CaCO3) range from -17.0 to -15.7 ‰, with the highest values during the period of 1450-1850 AD, coeval with the well-documented Little Ice Age (LIA) cold interval in Alaska. The high d18O values during the cold LIA are interpreted as reflecting shifts in atmospheric circulation. A weakening of the wintertime Aleutian low pressure system residing over the Gulf of Alaska during the LIA would have resulted in 18O-enriched winter precipitation as well as a colder and possibly drier winter climate in south-central Alaska. Also, elevated calcite contents of >80 % during the LIA reflect a lowering of lake level and/or enhanced seasonality (warmer summer and colder winter), as calcite precipitation in freshwater lakes is primarily a function of peak summer temperature and water depth. This interpretation is also supported by high d13C values, likely reflecting high aquatic productivity or increased residence times of the lake water during lower lake levels. The lower lake levels and warmer summers would have increased evaporative enrichment in 18O, also contributing to the high d18O values during the LIA. Our results indicate that changes in atmospheric circulation were an important component of climate change during the last millennium, exerting strong influence on regional climate in Alaska and the Arctic. STUDY NOTES: Multiproxy sediment data from Kepler Lake, south-central Alaska, for the past 800 years. Kepler Lake is a groundwater-fed marl lake. Paleoenvironmental proxies measured include stable isotopes, C/N ratios, Loss-on-ignition, and bulk sediment density. Kepler Lake, Alaska: 61°33'16"N, 149°12'43"W, 22m elevation. NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Gonyo, A.W. Investigator : Yu, Z. Investigator : Bebout, G.E. 2012-06-30 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/13077 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.xls https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.xls English https://www.ncdc.noaa.gov/paleo/study/13077 https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.txt https://www1.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.xls Gonyo, A.W., Z. Yu, and G.E. Bebout. 2012. Late Holocene change in climate and atmospheric circulation inferred from geochemical records at Kepler Lake, south-central Alaska. Journal of Paleolimnology, Vol. 48, No. 1, June 2012, pp. 55-67. DOI: 10.1007/s10933-012-9603-8 START YEAR: 1222 AD * END YEAR: 2007 AD -149.2119 61.5544 -149.2119 61.5544