Kepler Lake, Alaska 800 Year Multiproxy Sediment Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: Please cite original reference when using these data, plus the data file URL and date accessed. NAME OF DATA SET: Kepler Lake, Alaska 800 Year Multiproxy Sediment Data LAST UPDATE: 6/2012 (Original receipt by WDC Paleo) CONTRIBUTORS: Gonyo, A.W., Z. Yu, and G.E. Bebout IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2012-092 WDC PALEO CONTRIBUTION SERIES CITATION: Gonyo, A.W., et al. 2012. Kepler Lake, Alaska 800 Year Multiproxy Sediment Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2012-092. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: 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 ABSTRACT: 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. GEOGRAPHIC REGION: Northwestern North America PERIOD OF RECORD: 800 YrBP - present FUNDING SOURCES: DATA FILE URLS: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.txt ftp://ftp.ncdc.noaa.gov/pub/data/paleo/paleolimnology/northamerica/usa/alaska/kepler2012.xls DESCRIPTION: 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. DATA: 1. Radiocarbon dates from Kepler Lake, Alaska (Gonyo et al. 2012. JOPL) Core Depth(cm) Material Dated AMSLab#* 14CdatesYrBP±SE CalibratedAge MedianDateAD SampleSize(mgC) 1 45-46 Leaf frags,BirchScales 42048 190 ± 15 1663 -1951 1775 0.18 1 54-55 Leaf fragments 42049 (-) 520 ± 20 Rejected Rejected 0.05 (modern carbon) 1 66-67 Leaf frags,BirchScales 42050 340 ± 20 1473 – 1635 1565 0.14 1 84-85 Leaf stem,BirchScales 42051 540 ± 20 1324 - 1431 1408 0.1 2 99-100 Birch seeds,BirchScales 54644 790 ± 15 1220 - 1267 1243 0.13 *Samples analyzed by the Keck Carbon Cycle Accelerator Mass Spectrometry Laboratory at the University of California Irvine **Calibrated by the program CALIB Rev 5.0.2 (Stuiver and Reimer, 1993) using INTCAL 04.14c data set (Reimer et al. 2004) 1b. 210Pb dates from Kepler Lake, Alaska (Gonyo et al. 2012. JOPL) Core Depth(cm) 210PbActivity(Dpm/g) 210PbAgeAD 1S Error(years) 1 0-1 2.52 Unable to Reach Background 1 1-2 2.43 " 1 2-3 2.13 " 1 3-4 1.62 " 1 4-5 1.86 " 1 6-7 1.48 " 1 8-9 1.14 " 1 11-12 2.1 " 1 13-14 1.66 " 1 15-16 2.68 " 2 0-1 3.9 2007.6 0 2 2-3 3.76 2002.6 0.7 2 5-6 3.46 1995.4 1.4 2 8-9 3.09 1986.9 3 2 11-12 2.91 1974.7 4.4 2 14-15 2.31 1958.8 9.2 2 19-20 1.41 1915.6 37.2 2 22-23 1.1 Estimated Background 0.985 dpm/g 2 24-25 0.96 2 29-30 0.9 2. Surface water and plant analysis results from Kepler Lake and other lakes in south-central Alaska (Gonyo et al. 2012. JOPL) WaterSampleLocation d18O(‰) d2H(‰) DIC 13C(‰) ModernOrganicSamples Modern Organic Matter d13C (‰) Kepler Lake -16.46 -131.19 Fern -31.99 Mirror Lake -13.19 -113.40 Algal Floating Mat -31.24 Edmonds Lake -13.29 -112.05 Equisetum -30.24 Matanuska Lake -12.68 -110.82 Chara Stalks -29.85 Echo Lake -14.33 -121.95 Poaceae -27.26 Spring above Kepler Lake -17.62 -137.63 Picea Bark -27.71 Canoe Lake -14.95 -126.13 Picea Twig -27.26 Irene Lake -12.97 -114.36 Picea Needle -28.94 Long Lake -13.44 -114.64 Poplar Bark -26.96 Judy Crofby's well -19.14 -147.16 Poplar Twig -29.77 Fish Lake -16.73 -135.22 Poplar Leaves -29.55 Long Lake (Mile 86) -13.99 -124.60 Betula Bark -28.48 Hundred Mile Lake -15.38 -138.62 Betula Twig -30.09 Matanuska Glacier State -18.93 -152.48 Betula Leaves -31.77 Birch Lake -13.81 -124.47 Wasilla Lake -7.64 -77.23 Anchorage rain water -13.94 -117.73 Kepler Lake, AK Boat Lau -16.76 -136.12 -9.47 Kepler Lake, AK Wetland -18.19 -144.65 -9.01 Kepler Lake, AK Rainwate -19.39 -166.69 Hamilton's Well, AK Outd -16.75 -129.91 3a. Core data analysis results from Kepler Lake, Alaska (Gonyo et al., 2012. JOPL) Core 1 LOI and calcite isotopes Loss on Ignition (%) of organic Matter, Silicates, and CaCO3 Core1(C1)TopDepth YearAD BulkDens LOI-org LOI-Silic LOI-CaCO3 d18OCalcite d13Ccalcite 0 2007 0.20 5.25 14.97 79.78 -16.79 -7.97 1 2002 -16.54 -8.00 2 1997 0.24 5.14 11.99 82.87 -16.68 -7.91 3 1992 0.25 4.15 10.37 85.48 -16.61 -8.07 4 1986 0.34 4.86 10.77 84.37 -16.57 -7.97 5 1981 0.43 4.20 12.20 83.60 -16.56 -8.02 6 1976 0.64 3.92 11.93 84.15 -16.59 -8.00 7 1971 0.57 3.96 12.06 83.98 -16.55 -7.99 8 1966 0.33 6.34 12.57 81.10 -16.60 -7.97 9 1961 0.44 3.76 12.23 84.01 -16.46 -7.97 10 1955 0.36 3.96 12.64 83.40 -16.52 -7.96 11 1950 0.37 3.87 12.90 83.23 -16.41 -7.95 12 1945 0.39 4.61 12.55 82.84 -16.62 -7.97 13 1940 0.34 4.47 13.46 82.07 -16.67 -8.07 14 1935 0.54 4.89 14.50 80.61 -16.90 -8.03 15 1930 0.22 4.73 14.34 80.93 -16.73 -8.15 16 1925 0.31 5.22 14.95 79.83 -16.70 -8.09 17 1919 0.30 4.47 12.84 82.69 -16.67 -8.03 18 1914 0.42 4.80 13.41 81.78 -16.64 -8.00 19 1909 0.37 4.34 13.11 82.55 -16.54 -8.03 20 1904 0.33 4.37 12.90 82.73 -16.61 -8.01 21 1899 0.29 3.88 12.59 83.52 -16.45 -7.97 22 1894 0.34 4.15 12.51 83.34 -16.58 -7.91 23 1888 0.54 4.18 12.67 83.15 -16.48 -7.96 24 1883 0.34 3.83 12.52 83.65 -16.69 -7.89 25 1878 0.43 4.18 13.37 82.46 -16.50 -7.85 26 1873 0.36 3.80 12.83 83.37 -16.68 -7.65 27 1868 0.43 3.83 11.35 84.81 -16.39 -7.42 28 1863 0.40 3.34 11.19 85.48 -16.62 -7.42 29 1857 0.38 3.87 11.41 84.72 -16.38 -7.03 30 1852 0.40 3.72 12.33 83.96 -16.47 -7.06 31 1847 0.46 3.86 11.67 84.47 -16.47 -7.09 32 1842 0.46 3.76 12.39 83.84 -16.41 -7.00 33 1837 0.51 3.76 12.52 83.72 -16.42 -7.17 34 1832 0.48 4.82 16.88 78.30 -16.33 -7.12 35 1827 0.49 4.35 15.84 79.80 -15.96 -7.01 36 1821 0.36 5.54 19.17 75.29 -16.29 -7.16 37 1816 0.43 4.25 16.58 79.17 -15.82 -7.01 38 1811 0.52 4.23 18.44 77.33 -15.75 -6.93 39 1806 0.48 4.63 17.70 77.67 -15.88 -7.01 40 1801 0.44 4.12 16.33 79.55 -15.85 -7.05 41 1796 0.65 3.14 12.56 84.29 -16.03 -7.31 42 1790 0.46 4.11 11.68 84.21 -15.92 -7.28 43 1785 0.50 3.85 11.79 84.37 -16.04 -7.36 44 1780 0.54 3.15 8.62 88.23 -16.18 -7.67 45 1775 0.50 3.35 9.52 87.12 -16.06 -7.87 46 1765 0.52 3.60 10.73 85.67 -16.10 -7.85 47 1755 0.53 3.68 11.31 85.02 -16.04 -7.20 48 1745 0.62 3.73 11.75 84.51 -16.20 -7.05 49 1735 0.60 3.78 12.33 83.89 -16.28 -7.34 50 1725 0.54 4.42 14.47 81.11 -16.70 -7.41 51 1715 0.56 4.78 14.57 80.65 -16.29 -6.83 52 1705 0.44 4.59 15.05 80.35 -16.16 -7.24 53 1695 0.62 4.70 15.71 79.59 -16.34 -7.22 54 1685 0.45 4.41 14.69 80.90 -16.19 -7.12 55 1675 0.53 4.27 11.20 84.53 -15.78 -6.88 56 1665 0.56 3.74 12.85 83.41 -16.04 -7.00 57 1655 0.49 3.94 13.63 82.43 -16.00 -7.43 58 1645 0.46 3.94 14.88 81.18 -16.14 -7.70 59 1635 0.49 4.11 15.02 80.86 -16.17 -7.79 60 1625 0.50 4.25 13.07 82.68 -16.03 -7.58 61 1615 0.53 3.61 13.04 83.35 -16.13 -7.76 62 1605 0.46 5.25 21.66 73.09 -16.03 -7.93 63 1595 0.46 5.58 26.04 68.38 -16.16 -8.44 64 1585 0.48 5.07 21.96 72.97 -15.92 -8.51 65 1575 0.43 6.42 18.93 74.65 -16.07 -8.44 66 1565 0.51 5.35 19.34 75.31 -15.95 -8.37 67 1556 0.50 5.51 18.13 76.36 -16.46 -8.66 68 1548 0.47 5.13 17.92 76.95 -16.46 -8.15 69 1539 0.44 4.81 17.24 77.94 -16.49 -8.08 70 1530 0.37 5.58 20.56 73.86 -16.19 -8.06 71 1521 0.43 5.88 20.78 73.34 -16.53 -8.38 72 1513 0.51 4.52 16.34 79.14 -16.25 -8.02 73 1504 0.48 4.75 20.03 75.21 -16.51 -8.52 74 1495 0.52 4.14 16.36 79.50 -16.17 -8.29 75 1487 0.62 4.35 18.15 77.50 -16.44 -8.45 76 1478 0.57 4.65 18.87 76.48 -16.15 -8.36 77 1469 0.57 4.75 20.17 75.08 -16.30 -8.93 78 1460 0.47 4.70 21.16 74.15 -16.51 -8.82 79 1452 0.50 5.08 17.65 77.28 -16.96 -8.49 80 1443 0.58 4.93 14.78 80.29 -16.96 -8.24 81 1434 0.65 3.90 11.33 84.78 -16.82 -8.49 82 1425 0.58 4.31 14.52 81.17 -16.67 -8.46 83 1417 0.55 3.86 14.83 81.32 -16.45 -7.98 84 1408 0.66 4.30 11.51 84.20 -16.78 -7.84 Core C1 Isotopes and C/N d13C and d15N of Organic matter, per mil TopDepth YearAD d13C-org d15N-org C/N 0 2007 -34.57 5.59 12.19 2 1997 -33.41 5.92 9.28 4 1986 -32.91 4.83 6.49 6 1976 -32.15 4.07 4.95 8 1966 -33.55 4.28 8.82 10 1955 -33.22 4.26 7.48 12 1945 -33.54 4.97 9.42 14 1935 -34.21 5.01 8.29 16 1925 -34.22 5.24 6.96 18 1914 -34.10 5.07 8.93 20 1904 -33.69 4.88 8.72 22 1894 -33.76 4.14 10.08 24 1883 -33.73 4.08 10.00 26 1873 -33.61 3.63 10.70 28 1863 -33.43 2.86 9.48 30 1852 -33.40 1.79 9.16 32 1842 -32.95 1.69 10.25 34 1832 -33.30 1.81 10.75 36 1821 -32.02 2.91 14.64 38 1811 -32.70 0.86 12.26 40 1801 -33.09 1.07 9.27 42 1790 -33.24 1.72 8.01 44 1780 -33.73 2.35 9.12 46 1765 -34.13 1.96 9.55 48 1745 -33.01 1.65 11.30 50 1725 -33.71 1.86 10.34 52 1705 -34.22 1.74 9.58 54 1685 -34.13 1.74 12.35 56 1665 -33.46 1.74 10.93 58 1645 -33.64 1.27 8.90 60 1625 -32.71 0.90 9.35 62 1605 -34.09 1.35 11.67 64 1585 -35.55 1.54 6.75 66 1565 -35.55 1.36 10.57 68 1548 -35.40 2.07 17.43 70 1530 -35.31 1.28 7.08 72 1513 -35.29 2.26 5.96 74 1495 -35.85 1.55 12.06 76 1478 -35.22 2.08 5.32 78 1460 -36.47 1.78 10.77 80 1443 -35.79 2.43 17.71 82 1425 -35.66 1.87 10.43 84 1408 -35.55 0.89 Core 2 LOI and calcite isotopes Loss on Ignition of organic Matter, Silicates, and CaCO3 TopDepthCm YearAD BulkDens LOI-org LOI-Silic LOI-CaCO3 d18OCalcite d13Ccalcite 0 2007 0.29 7.98 19.50 72.52 -16.53 -9.00 1 2005 0.30 8.46 21.36 70.18 -16.55 -8.69 2 2004 0.27 8.35 22.38 69.27 -16.55 -8.84 3 2002 0.22 8.65 26.02 65.33 -16.59 -9.11 4 2000 0.25 9.11 23.81 67.08 -16.56 -8.73 5 1998 0.29 9.11 23.54 67.35 -16.61 -8.52 6 1995 0.25 9.41 28.75 61.84 -16.57 -8.44 7 1992 0.25 9.14 28.87 61.98 -16.49 -8.58 8 1989 0.37 8.51 28.74 62.76 -16.10 -8.29 9 1986 0.31 8.31 26.39 65.30 -16.20 -8.61 10 1982 0.25 8.44 24.22 67.34 -16.21 -8.47 11 1978 0.27 7.86 23.31 68.83 -16.05 -8.40 12 1974 0.28 7.61 21.17 71.21 -16.01 -8.40 13 1970 0.40 7.02 19.38 73.60 -16.07 -8.29 14 1967 0.30 6.82 19.55 73.63 -15.99 -8.20 15 1964 0.31 6.39 19.29 74.33 -15.96 -8.22 16 1960 0.49 6.81 19.61 73.57 -15.97 -8.24 17 1957 0.38 6.80 19.09 74.11 -15.97 -8.11 18 1953 0.45 6.83 18.81 74.36 -15.89 -7.94 19 1948 0.38 5.64 14.20 80.16 -15.89 -7.92 20 1942 0.50 5.78 14.82 79.40 -15.89 -7.95 21 1936 0.57 5.03 12.66 82.32 -15.83 -7.87 22 1930 0.47 5.32 14.56 80.13 -15.80 -7.95 23 1925 0.54 5.30 14.22 80.48 -15.70 -7.65 24 1919 0.49 5.53 14.61 79.86 -15.69 -7.48 25 1913 0.50 5.78 16.16 78.06 -15.75 -7.47 26 1907 0.47 6.69 17.28 76.03 -15.80 -7.39 27 1902 0.50 5.99 16.32 77.69 -15.77 -7.21 28 1896 0.55 5.59 15.19 79.22 -15.78 -7.03 29 1890 0.49 6.02 16.31 77.66 -15.80 -6.83 30 1884 0.48 6.23 14.94 78.83 -15.92 -6.84 31 1879 0.41 6.65 14.30 79.05 -15.91 -6.71 32 1873 0.48 6.21 14.79 79.01 -15.94 -6.56 33 1867 0.57 5.91 14.80 79.28 -15.85 -6.61 34 1861 0.53 6.25 15.44 78.30 -15.97 -6.43 35 1856 0.40 6.57 15.04 78.40 -15.86 -6.47 36 1850 0.52 6.53 16.49 76.99 -15.79 -6.38 37 1844 0.49 6.72 16.11 77.17 -15.89 -6.53 38 1838 0.43 6.90 17.23 75.88 -15.85 -6.69 39 1833 0.50 6.51 14.38 79.11 -15.91 -6.56 40 1827 0.50 6.42 15.94 77.63 -15.79 -6.61 41 1821 0.49 6.58 18.75 74.67 -15.82 -6.60 42 1813 0.54 6.35 16.95 76.71 -15.76 -6.63 43 1805 0.52 6.49 17.12 76.38 -15.91 -6.81 44 1798 0.53 5.57 15.46 78.97 -15.78 -6.73 45 1790 0.58 5.34 13.88 80.78 -15.73 -6.50 46 1782 0.53 5.25 14.31 80.44 -15.64 -6.60 47 1774 0.53 5.32 15.10 79.59 -15.70 -6.74 48 1766 0.65 5.17 14.63 80.20 -15.65 -6.81 49 1759 0.59 5.12 13.87 81.01 -15.52 -6.54 50 1751 0.58 5.33 14.75 79.92 -15.66 -6.57 51 1743 0.62 5.28 15.15 79.57 -15.69 -6.98 52 1735 0.56 5.25 14.36 80.38 -15.62 -6.77 53 1727 0.56 5.62 19.04 75.33 -15.43 -6.50 54 1720 0.46 6.54 27.53 65.93 -15.14 -6.52 55 1712 0.60 5.62 18.07 76.31 -15.36 -7.06 56 1704 0.54 5.33 13.85 80.82 -15.38 -6.49 57 1696 0.58 5.12 13.80 81.08 -15.26 -6.11 58 1689 0.49 5.88 15.22 78.91 -15.63 -7.17 59 1681 0.57 5.61 13.50 80.90 -15.51 -6.95 60 1673 0.56 6.38 18.63 74.99 -15.20 -6.59 61 1665 0.52 6.23 18.14 75.63 -15.53 -7.30 62 1657 0.53 6.41 18.46 75.12 -15.87 -7.68 63 1650 0.49 6.30 18.05 75.65 -15.95 -7.63 64 1642 0.45 7.07 19.15 73.77 -16.13 -7.52 65 1634 0.50 6.74 18.40 74.87 -16.03 -7.69 66 1626 0.44 6.79 18.47 74.75 -15.72 -7.51 67 1618 0.51 6.64 18.62 74.74 -15.54 -7.29 68 1611 0.49 6.53 19.57 73.91 -15.64 -7.40 69 1603 0.42 8.43 27.95 63.61 -16.22 -8.76 70 1595 0.39 7.94 30.20 61.86 -15.80 -8.46 71 1585 0.42 7.84 27.88 64.28 -15.89 -8.69 72 1575 0.43 6.74 28.36 64.91 -15.85 -8.91 73 1565 0.46 7.35 30.65 62.01 -15.90 -9.32 74 1555 0.44 7.93 36.95 55.12 -15.67 -8.76 75 1545 0.50 8.14 28.18 63.68 -15.63 -8.26 76 1535 0.48 8.41 30.34 61.26 -16.05 -8.29 77 1525 0.44 7.72 27.18 65.10 -16.18 -8.53 78 1515 0.47 7.10 27.93 64.96 -16.16 -8.15 79 1505 0.42 6.97 31.30 61.74 -15.96 -8.35 80 1495 0.47 5.78 23.74 70.48 -15.95 -8.43 81 1489 0.45 5.74 25.29 68.98 -16.17 -8.73 82 1483 0.44 6.62 27.37 66.01 -16.15 -9.10 83 1477 0.44 7.03 31.27 61.70 -16.11 -9.60 84 1471 0.45 6.91 29.69 63.41 -16.02 -9.29 85 1465 0.41 7.43 31.50 61.07 -16.12 -8.39 86 1458 0.50 7.16 28.39 64.45 -16.40 -8.10 87 1452 0.53 6.39 24.95 68.66 -16.32 -8.02 88 1446 0.54 6.53 23.38 70.09 -16.71 -8.44 89 1440 0.51 6.61 22.35 71.05 -16.57 -8.51 90 1434 0.54 6.33 18.40 75.28 -16.29 -8.67 91 1413 0.54 6.00 19.15 74.85 -16.01 -8.81 92 1392 0.50 6.60 22.13 71.27 -16.10 -8.79 93 1370 0.44 6.82 20.46 72.72 -16.73 -9.05 94 1349 0.52 7.58 23.05 69.37 -17.35 -8.70 95 1328 0.48 7.36 28.04 64.60 -16.80 -8.66 96 1307 0.47 7.23 28.04 64.73 -16.46 -8.81 97 1285 0.46 7.68 31.45 60.87 -16.41 -8.88 98 1264 0.57 7.21 26.15 66.64 -16.39 -8.87 99 1243 0.61 7.38 31.04 61.59 -16.06 -8.72 100 1222 0.67 6.97 28.85 64.17 -15.86 -8.51 Core C2 Isotopes and C/N d13C and d15N of Organic matter, per mil TopDepth YearAD d13Corg d15Norg C/N 0 2007 -35.31 7.99 8.59 2 2004 -36.05 7.10 8.54 4 2000 -35.93 5.99 10.03 6 1995 -35.95 4.99 9.97 8 1989 -34.26 4.76 15.65 10 1982 -35.58 4.35 10.77 12 1974 -35.24 4.09 9.03 14 1967 -34.81 4.23 9.97 16 1960 -35.08 3.78 8.83 18 1953 -34.23 3.70 10.20 20 1942 -33.46 4.03 9.27 22 1930 -33.74 3.81 8.02 24 1919 -34.48 3.15 10.15 26 1907 -35.00 3.21 10.39 28 1896 -34.84 2.39 9.30