Huascarán Ice Core Data: Readme file --------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program --------------------------------------------------------------------- NOTE: PLEASE CITE ORIGINAL REFERENCE WHEN USING THIS DATA!!!!! NAME OF DATA SET: Huascarán Ice Core Data LAST UPDATE: 8/2013 (addition of annions data file). Original receipt by WDC Paleo 1/2001 CONTRIBUTOR: Lonnie G. Thompson, Byrd Polar Research Center of The Ohio State University IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2001-008 SUGGESTED DATA CITATION: Thompson, L.G., 2001, Huascarán Ice Core Data, IGBP PAGES/World Data Center A for Paleoclimatology Data Contribution Series #2001-008. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Thompson, L.G., E. Mosley-Thompson, M.E. Davis, P-N. Lin, K.A. Henderson, J. Cole-Dai, J.F. Bolzan and K-b. Liu. 1995. Late Glacial Stage and Holocene tropical ice core records from Huascarán, Peru. Science, 269, 46-50. GEOGRAPHIC REGION: South America, Peruvian Andes PERIOD OF RECORD: 19.5 KYrBP - present LIST OF FILES: Readme_Huascaran.txt (this file), ASCII text data files: age.txt Age-scale/averaging doc. all-mo.txt Linearized profiles 100yr. annualc.txt Cal. Annual avg for 100yr. annualt.txt Thermal Annual avg - 100yr. hs12-5m.txt 5m/.5m/every averages hs1layer.txt C1 layer depths/thickness hs2layer.txt C2 layer depths/thickness hs2-100a.txt Revised C2 100-yr averages. annions.txt decadal averages of major anions (Chloride, Nitrate, Sulfate) DESCRIPTION: General Information about the Huascarán Ice Cores Site Description and Analysis In July-August 1993, two ice cores to bedrock were recovered from the col between the north and south peaks of Nevado Huascarán, Peru (9øS, 77ø30'W, col elevation 6050 m) and were subsequently transported back to the cold room facility at the Byrd Polar Research Center (BPRC). Core 1 (HSC1, 160.40 m) was sectioned in the field into 2677 samples decreasing in thickness from 13 cm at the top to 3 cm at the base, which were then melted and poured into 2 or 4 oz. plastic (HDPE) bottles, and sealed with wax. Core 2 (HSC2, 166.08 m), drilled approximately 100 m from the HSC1 site, was returned frozen in 1 m sections. Ice motion vectors determined from stake movements from 1991-93 indicate that the drill sites are proximal to the divide between ice flow towards the east and west outlets of the col. Visible observations and borehole temperatures indicate that the glacier is 'polar' type, i.e., it remains frozen to the bed (Thompson et al., Science, v.269, 1995, p. 46-50). Each ice sample from HSC2 was prepared in a Class 100 clean room environment, and analyzed for major anion concentrations (Cl-, NO3-, and SO42-) on a Dionex 2010i ion chromatograph, d18O on a Finnigan Mat mass spectrometer (Craig, 1957), and for particulate concentration and size distribution using a Coulter TA-II particle counter (Thompson, OSU IPS Report 46, 1973). A complete d18O profile was also produced from the bottled samples from HSC1. Contamination during field preparation and transport of these samples precluded the development of a second complete record of particles and anion concentrations. For display purposes, variable averaging on the core depth scale was utilized to show the major large-scale events in the record without the confusion of the large annual variations superimposed upon the upper portion. Hence, for HSC2, 5-m integrated averages were calculated for between the surface and 140 meters depth and then 50-cm averages were generated between 140 and 160 meters. Between 160 and 166 meters, every sample value was plotted. A similar scheme was used for HSC1 (all values plotted for 155-160.4 m). These data are included in hs12-5m.txt in this data archive, and the graph can be seen in Thompson et al., 1995 (Fig. 3). Development of the time/depth relationship Tropical South American climate is marked by annual dry seasons (July-October) which were identifiable in the ice core record as elevated values in all relevant measurements. The nitrate (NO3-) record from the Huascarán ice core provided the most definitive seasonal marker, but the final time scale was constructed from a comparison of four major parameters (NO3-, d18O, dust and SO42-). Each annual maximum corresponds to the middle of the dry season, assumed to occur on the 1st of August. The rapid layer- thinning below 120 m limited annual resolution to the most recent 270 years. However, the high accumulation and strong preservation of seasonal cycles also made possible the subannual resolution of d18O variations for a period of at least 100 years (1894-1993). The accuracy of the time scale is of paramount importance in the development of relationships between ice core proxy data and tropical climate conditions. Several horizons in recent times were useful for confirming the layer counting as a reliable method, and indicate almost certain ages for the uppermost 50 years. In 1980, during the original reconnaissance expedition to Huascarán, a 10 m firn core was extracted and analyzed for d18O at BPRC (Thompson et al., JGR, v. 89d3, 1984, p. 4638-4646). Aside from minor accumulation variation and slight signal attenuation, the 1993 cores duplicated the earlier stable isotope profile over the common portion, and confirmed the layer counting to 1980 as absolute. Additionally, a magnitude 7.7 earthquake struck coastal Peru in May 1970, generating large mud flows following the collapse of a large portion of the Huascarán glacier from the north peak. The event was recognized in the ice core by a sharp two-year rise in particulates from the newly-created sediment source. A third time horizon was provided by the HSC2 36Cl profile (Synal et al., Glaciers From the Alps, Paul Scherrer Inst., 1997, p. 99-102), a substance produced by neutron activation during the explosion of atomic devices in the presence of a 35Cl source, such as sea water. An abrupt >100-fold rise in 36Cl concentration occurred at ~54 m depth, which dates (by layer counting) to 1951-53. This was in direct response to the October 31, 1952 U.S. 'Ivy' surface test of an experimental nuclear device on the Eniwetok Atoll in the Pacific Ocean (11øN, 162øE) (Carter and Moghissi, Health Physics, v. 33, 1977, p. 55-71). Finally, in both HSC1 and HSC2, the 1883 eruption of Krakatau, Indonesia (6øS, 105ø30'E) was identified by an anomalous sulfate concentration of ~400 ppb at 110 m depth, more than twice the level of any other local (within 10 m) event. A date of mid- year 1884 was thus considered to be an absolute time marker for both cores within the error of the time lag (less than one year). THERMAL YEAR (Aug.-Jul.) LAYER THICKNESSES Huascaran (1993) Core 2 Year Core Depth Layer Mean IED Bottom IED Layer Bottom (m) Thickness Density (m) Thickness 1993 - 0 0 1992 -93 3.36 3.36 0.346 1.528 1.528 1991 -92 5.27 1.91 0.491 2.606 1.078 1990 -91 7.97 2.70 0.547 4.302 1.696 1989 -90 9.85 1.88 0.608 5.580 1.278 1988 -89 12.30 2.45 0.642 7.343 1.763 1987 -88 13.79 1.49 0.681 8.464 1.121 1986 -87 15.50 1.71 0.703 9.794 1.330 1985 -86 17.06 1.56 0.728 11.047 1.253 1984 -85 18.56 1.50 0.750 12.287 1.240 1983 -84 20.38 1.82 0.771 13.837 1.550 1982 -83 21.98 1.60 0.796 15.241 1.404 1981 -82 23.35 1.37 0.818 16.473 1.232 1980 -81 24.74 1.39 0.836 17.750 1.277 1979 -80 25.56 0.82 0.854 18.515 0.765 1978 -79 26.85 1.29 0.863 19.735 1.220 1977 -78 27.86 1.01 0.877 20.704 0.969 1976 -77 28.61 0.75 0.888 21.430 0.726 1975 -76 29.65 1.04 0.894 22.446 1.016 1974 -75 30.67 1.02 0.903 23.451 1.005 1973 -74 31.55 0.88 0.910 24.324 0.873 1972 -73 32.70 1.15 0.915 25.471 1.147 1971 -72 33.98 1.28 0.920 26.751 1.280 1970 -71 35.38 1.40 0.920 28.151 1.400 1969 -70 36.62 1.24 0.920 29.391 1.240 1968 -69 37.89 1.27 0.920 30.661 1.270 1967 -68 39.15 1.26 0.920 31.921 1.260 1966 -67 40.85 1.70 0.920 33.621 1.700 1965 -66 41.78 0.93 0.920 34.551 0.930 1964 -65 42.80 1.02 0.920 35.571 1.020 1963 -64 43.81 1.01 0.920 36.581 1.010 1962 -63 44.54 0.73 0.920 37.311 0.730 1961 -62 45.79 1.25 0.920 38.561 1.250 1960 -61 47.26 1.47 0.920 40.031 1.470 1959 -60 48.42 1.16 0.920 41.191 1.160 1958 -59 49.52 1.10 0.920 42.291 1.100 1957 -58 50.38 0.86 0.920 43.151 0.860 1956 -57 51.11 0.73 0.920 43.881 0.730 1955 -56 51.83 0.72 0.920 44.601 0.720 1954 -55 52.80 0.97 0.920 45.571 0.970 1953 -54 53.65 0.85 0.920 46.421 0.850 1952 -53 54.44 0.79 0.920 47.211 0.790 1951 -52 55.19 0.75 0.920 47.961 0.750 1950 -51 55.93 0.74 0.920 48.701 0.740 1949 -50 56.55 0.62 0.920 49.321 0.620 1948 -49 57.24 0.69 0.920 50.011 0.690 1947 -48 57.92 0.68 0.920 50.691 0.680 1946 -47 58.64 0.72 0.920 51.411 0.720 1945 -46 59.44 0.80 0.920 52.211 0.800 1944 -45 60.37 0.93 0.920 53.141 0.930 1943 -44 61.27 0.90 0.920 54.041 0.900 1942 -43 62.26 0.99 0.920 55.031 0.990 1941 -42 63.69 1.43 0.920 56.461 1.430 1940 -41 64.72 1.03 0.920 57.491 1.030 1939 -40 65.51 0.79 0.920 58.281 0.790 1938 -39 66.39 0.88 0.920 59.161 0.880 1937 -38 67.41 1.02 0.920 60.181 1.020 1936 -37 68.41 1.00 0.920 61.181 1.000 1935 -36 69.10 0.69 0.920 61.871 0.690 1934 -35 69.86 0.76 0.920 62.631 0.760 1933 -34 70.62 0.76 0.920 63.391 0.760 1932 -33 71.44 0.82 0.920 64.211 0.820 1931 -32 72.08 0.64 0.920 64.851 0.640 1930 -31 73.03 0.95 0.920 65.801 0.950 1929 -30 73.88 0.85 0.920 66.651 0.850 1928 -29 74.72 0.84 0.920 67.491 0.840 1927 -28 75.37 0.65 0.920 68.141 0.650 1926 -27 76.34 0.97 0.920 69.111 0.970 1925 -26 77.57 1.23 0.920 70.341 1.230 1924 -25 78.52 0.95 0.920 71.291 0.950 1923 -24 79.76 1.24 0.920 72.531 1.240 1922 -23 81.23 1.47 0.920 74.001 1.470 1921 -22 82.08 0.85 0.920 74.851 0.850 1920 -21 82.96 0.88 0.920 75.731 0.880 1919 -20 83.82 0.86 0.920 76.591 0.860 1918 -19 84.67 0.85 0.920 77.441 0.850 1917 -18 85.66 0.99 0.920 78.431 0.990 1916 -17 86.72 1.06 0.920 79.491 1.060 1915 -16 87.89 1.17 0.920 80.661 1.170 1914 -15 88.57 0.68 0.920 81.341 0.680 1913 -14 89.28 0.71 0.920 82.051 0.710 1912 -13 90.07 0.79 0.920 82.841 0.790 1911 -12 90.96 0.89 0.920 83.731 0.890 1910 -11 91.82 0.86 0.920 84.591 0.860 1909 -10 92.73 0.91 0.920 85.501 0.910 1908 - 9 94.35 1.62 0.920 87.121 1.620 1907 - 8 95.43 1.08 0.920 88.201 1.080 1906 - 7 96.36 0.93 0.920 89.131 0.930 1905 - 6 97.11 0.75 0.920 89.881 0.750 1904 - 5 97.53 0.42 0.920 90.301 0.420 1903 - 4 98.02 0.49 0.920 90.791 0.490 1902 - 3 98.61 0.59 0.920 91.381 0.590 1901 - 2 99.25 0.64 0.920 92.021 0.640 1900 - 1 99.85 0.60 0.920 92.621 0.600 1899 - 0 100.66 0.81 0.920 93.431 0.810 1898 -99 101.45 0.79 0.920 94.221 0.790 1897 -98 102.12 0.67 0.920 94.891 0.670 1896 -97 103.00 0.88 0.920 95.771 0.880 1895 -96 103.92 0.92 0.920 96.691 0.920 1894 -95 104.55 0.63 0.920 97.321 0.630 1893 -94 105.33 0.78 0.920 98.101 0.780 1892 -93 106.10 0.77 0.920 98.871 0.770 1891 -92 106.80 0.70 0.920 99.571 0.700 1890 -91 107.33 0.53 0.920 100.101 0.530 1889 -90 107.98 0.65 0.920 100.751 0.650 1888 -89 108.35 0.37 0.920 101.121 0.370 1887 -88 109.02 0.67 0.920 101.791 0.670 1886 -87 109.41 0.39 0.920 102.181 0.390 1885 -86 109.85 0.44 0.920 102.621 0.440 1884 -85 110.28 0.43 0.920 103.051 0.430 1883 -84 110.61 0.33 0.920 103.381 0.330 1882 -83 111.02 0.41 0.920 103.791 0.410 1881 -82 111.20 0.18 0.920 103.971 0.180 1880 -81 111.60 0.40 0.920 104.371 0.400 1879 -80 111.80 0.20 0.920 104.571 0.200 1878 -79 112.15 0.35 0.920 104.921 0.350 1877 -78 112.40 0.25 0.920 105.171 0.250 1876 -77 112.69 0.29 0.920 105.461 0.290 1875 -76 112.90 0.21 0.920 105.671 0.210 1874 -75 113.16 0.26 0.920 105.931 0.260 1873 -74 113.37 0.21 0.920 106.141 0.210 1872 -73 113.52 0.15 0.920 106.291 0.150 1871 -72 113.66 0.14 0.920 106.431 0.140 1870 -71 113.82 0.16 0.920 106.591 0.160 1869 -70 113.98 0.16 0.920 106.751 0.160 1868 -69 114.13 0.15 0.920 106.901 0.150 1867 -68 114.32 0.19 0.920 107.091 0.190 1866 -67 114.48 0.16 0.920 107.251 0.160 1865 -66 114.68 0.20 0.920 107.451 0.200 1864 -65 114.85 0.17 0.920 107.621 0.170 1863 -64 115.07 0.22 0.920 107.841 0.220 1862 -63 115.20 0.13 0.920 107.971 0.130 1861 -62 115.35 0.15 0.920 108.121 0.150 1860 -61 115.48 0.13 0.920 108.251 0.130 1859 -60 115.610 0.13 0.920 108.381 0.130 1858 -59 115.720 0.11 0.920 108.491 0.110 1857 -58 115.805 0.09 0.920 108.576 0.085 1856 -57 115.920 0.11 0.920 108.691 0.115 1855 -56 116.030 0.11 0.920 108.801 0.110 1854 -55 116.140 0.11 0.920 108.911 0.110 1853 -54 116.285 0.14 0.920 109.056 0.145 1852 -53 116.420 0.14 0.920 109.191 0.135 1851 -52 116.510 0.09 0.920 109.281 0.090 1850 -51 116.650 0.14 0.920 109.421 0.140 1849 -50 116.810 0.16 0.920 109.581 0.160 1848 -49 116.895 0.08 0.920 109.666 0.085 1847 -48 116.995 0.10 0.920 109.766 0.100 1846 -47 117.075 0.08 0.920 109.846 0.080 1845 -46 117.190 0.11 0.920 109.961 0.115 1844 -45 117.270 0.08 0.920 110.041 0.080 1843 -44 117.365 0.09 0.920 110.136 0.095 1842 -43 117.480 0.12 0.920 110.251 0.115 1841 -42 117.550 0.07 0.920 110.321 0.070 1840 -41 117.630 0.08 0.920 110.401 0.080 1839 -40 117.745 0.12 0.920 110.516 0.115 1838 -39 117.870 0.13 0.920 110.641 0.125 1837 -38 117.985 0.11 0.920 110.756 0.115 1836 -37 118.040 0.06 0.920 110.811 0.055 1835 -36 118.130 0.09 0.920 110.901 0.090 1834 -35 118.185 0.06 0.920 110.956 0.055 1833 -34 118.260 0.08 0.920 111.031 0.075 1832 -33 118.320 0.06 0.920 111.091 0.060 1831 -32 118.405 0.09 0.920 111.176 0.085 1830 -31 118.490 0.08 0.920 111.261 0.085 1829 -30 118.580 0.09 0.920 111.351 0.090 1828 -29 118.645 0.06 0.920 111.416 0.065 1827 -28 118.730 0.09 0.920 111.501 0.085 1826 -27 118.805 0.08 0.920 111.576 0.075 1825 -26 118.850 0.04 0.920 111.621 0.045 1824 -25 118.890 0.04 0.920 111.661 0.040 1823 -24 118.940 0.05 0.920 111.711 0.050 1822 -23 119.000 0.06 0.920 111.771 0.060 1821 -22 119.065 0.06 0.920 111.836 0.065 1820 -21 119.120 0.06 0.920 111.891 0.055 1819 -20 119.165 0.05 0.920 111.936 0.045 1818 -19 119.230 0.06 0.920 112.001 0.065 1817 -18 119.260 0.03 0.920 112.031 0.030 1816 -17 119.345 0.08 0.920 112.116 0.085 1815 -16 119.425 0.08 0.920 112.196 0.080 1814 -15 119.515 0.09 0.920 112.286 0.090 1813 -14 119.585 0.07 0.920 112.356 0.070 1812 -13 119.675 0.09 0.920 112.446 0.090 1811 -12 119.750 0.08 0.920 112.521 0.075 1810 -11 119.840 0.09 0.920 112.611 0.090 1809 -10 119.915 0.075 0.920 112.686 0.075 1808 - 9 119.975 0.060 0.920 112.746 0.060 1807 - 8 120.040 0.065 0.920 112.811 0.065 1806 - 7 120.120 0.080 0.920 112.891 0.080 1805 - 6 120.175 0.055 0.920 112.946 0.055 1804 - 5 120.235 0.060 0.920 113.006 0.060 1803 - 4 120.280 0.045 0.920 113.051 0.045 1802 - 3 120.350 0.070 0.920 113.121 0.070 1801 - 2 120.430 0.080 0.920 113.201 0.080 1800 - 1 120.510 0.080 0.920 113.281 0.080 1799 - 0 120.565 0.055 0.920 113.336 0.055 1798 -99 120.610 0.045 0.920 113.381 0.045 1797 -98 120.700 0.090 0.920 113.471 0.090 1796 -97 120.760 0.060 0.920 113.531 0.060 1795 -96 120.805 0.045 0.920 113.576 0.045 1794 -95 120.890 0.085 0.920 113.661 0.085 1793 -94 121.000 0.110 0.920 113.771 0.110 1792 -93 121.085 0.085 0.920 113.856 0.085 1791 -92 121.180 0.095 0.920 113.951 0.095 1790 -91 121.220 0.040 0.920 113.991 0.040 1789 -90 121.285 0.065 0.920 114.056 0.065 1788 -89 121.330 0.045 0.920 114.101 0.045 1787 -88 121.390 0.060 0.920 114.161 0.060 1786 -87 121.470 0.080 0.920 114.241 0.080 1785 -86 121.565 0.095 0.920 114.336 0.095 1784 -85 121.665 0.100 0.920 114.436 0.100 1783 -84 121.725 0.060 0.920 114.496 0.060 1782 -83 121.790 0.065 0.920 114.561 0.065 1781 -82 121.860 0.070 0.920 114.631 0.070 1780 -81 121.920 0.060 0.920 114.691 0.060 1779 -80 122.010 0.090 0.920 114.781 0.090 1778 -79 122.065 0.055 0.920 114.836 0.055 1777 -78 122.100 0.035 0.920 114.871 0.035 1776 -77 122.160 0.060 0.920 114.931 0.060 1775 -76 122.215 0.055 0.920 114.986 0.055 1774 -75 122.285 0.070 0.920 115.056 0.070 1773 -74 122.375 0.090 0.920 115.146 0.090 1772 -73 122.430 0.055 0.920 115.201 0.055 1771 -72 122.510 0.080 0.920 115.281 0.080 1770 -71 122.575 0.065 0.920 115.346 0.065 1769 -70 122.625 0.050 0.920 115.396 0.050 1768 -69 122.670 0.045 0.920 115.441 0.045 1767 -68 122.710 0.040 0.920 115.481 0.040 1766 -67 122.760 0.050 0.920 115.531 0.050 1765 -66 122.810 0.050 0.920 115.581 0.050 1764 -65 122.875 0.065 0.920 115.646 0.065 1763 -64 122.940 0.065 0.920 115.711 0.065 1762 -63 122.990 0.050 0.920 115.761 0.050 1761 -62 123.035 0.045 0.920 115.806 0.045 1760 -61 123.075 0.040 0.920 115.846 0.040 1759 -60 123.130 0.055 0.920 115.901 0.055 1758 -59 123.175 0.045 0.920 115.946 0.045 1757 -58 123.225 0.050 0.920 115.996 0.050 1756 -57 123.285 0.060 0.920 116.056 0.060 1755 -56 123.325 0.040 0.920 116.096 0.040 1754 -55 123.400 0.075 0.920 116.171 0.075 1753 -54 123.480 0.080 0.920 116.251 0.080 1752 -53 123.585 0.105 0.920 116.356 0.105 1751 -52 123.645 0.060 0.920 116.416 0.060 1750 -51 123.670 0.025 0.920 116.441 0.025 1749 -50 123.710 0.040 0.920 116.481 0.040 1748 -49 123.770 0.060 0.920 116.541 0.060 1747 -48 123.805 0.035 0.920 116.576 0.035 1746 -47 123.855 0.050 0.920 116.626 0.050 1745 -46 123.920 0.065 0.920 116.691 0.065 1744 -45 123.950 0.030 0.920 116.721 0.030 1743 -44 124.025 0.075 0.920 116.796 0.075 1742 -43 124.075 0.050 0.920 116.846 0.050 1741 -42 124.120 0.045 0.920 116.891 0.045 1740 -41 124.170 0.050 0.920 116.941 0.050 1739 -40 124.210 0.040 0.920 116.981 0.040 1738 -39 124.250 0.040 0.920 117.021 0.040 1737 -38 124.330 0.080 0.920 117.101 0.080 1736 -37 124.390 0.060 0.920 117.161 0.060 1735 -36 124.465 0.075 0.920 117.236 0.075 1734 -35 124.535 0.070 0.920 117.306 0.070 1733 -34 124.580 0.045 0.920 117.351 0.045 1732 -33 124.620 0.040 0.920 117.391 0.040 1731 -32 124.665 0.045 0.920 117.436 0.045 1730 -31 124.715 0.050 0.920 117.486 0.050 1729 -30 124.775 0.060 0.920 117.546 0.060 1728 -29 124.840 0.065 0.920 117.611 0.065 1727 -28 124.875 0.035 0.920 117.646 0.035 1726 -27 124.925 0.050 0.920 117.696 0.050 1725 -26 125.000 0.075 0.920 117.771 0.075 1724 -25 125.037 0.037 0.920 117.808 0.037 1723 -24 125.074 0.037 0.920 117.845 0.037 1722 -23 125.111 0.037 0.920 117.882 0.037 1721 -22 125.147 0.036 0.920 117.918 0.036 1720 -21 125.182 0.035 0.920 117.953 0.035 1719 -20 125.216 0.034 0.920 117.987 0.034