NGRIP, GRIP, and GISP2 Synchronization Match Points ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!! NAME OF DATA SET: NGRIP, GRIP, and GISP2 Synchronization Match Points LAST UPDATE: File released November 27, 2006, received by WDC Paleo 12/2006. Original file name: NGRIP_GRIP_GISP2_match_points_27nov2006 CONTRIBUTORS: S.O. Rasmussen, I.K. Seierstad, K.K. Andersen, M. Bigler, D. Dahl-Jensen, and S.J. Johnsen. Ice and Climate Research Group, Niels Bohr Institute, University of Copenhagen, Denmark. See complete list of data contributors in the reference list below. IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2006-120 SUGGESTED DATA CITATION: S.O. Rasmussen, I.K. Seierstad, K.K. Andersen, M. Bigler, D. Dahl-Jensen, and S.J. Johnsen, 2006. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2006-120 NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. Please cite the relevant papers from the list below depending on the time interval used. ORIGINAL REFERENCE: The matching of the threee cores and the transferal of the GICC05 time scale to the GRIP and GISP2 cores is described in the paper: S.O. Rasmussen, I.K. Seierstad, K.K. Andersen, M. Bigler, D. Dahl-Jensen, and S.J. Johnsen. 2008. Synchronization of the NGRIP, GRIP, and GISP2 ice cores across MIS 2 and palaeoclimatic implications. Quaternary Science Reviews, Vol. 27, p. 18-28. ABSTRACT: We here present a synchronization of the NGRIP, GRIP, and GISP2 ice cores based mainly on volcanic events over the period 14.9-32.45 ka b2k (before AD 2000), corresponding to Marine Isotope Stage 2 (MIS 2) and the end of MIS 3. The matching provides a basis for applying the recent NGRIP- based Greenland Ice Core Chronology 2005 (GICC05) time scale to the GRIP and GISP2 ice cores, thereby making it possible to compare the synchronized palaeoclimate profiles of the cores in detail and to identify relative accumulation differences between the cores. Based on the matching, a period of anomalous high accumulation rates in the GISP2 ice core is detected within the period 16.5-18.3 ka b2k. The d18O and [Ca2+] profiles of the three cores are presented on the common GICC05 time scale and generally show excellent agreement across the stadial-interstadial transitions and across the two characteristic dust events in Greenland Stadial 3. However, large differences between the d18O and [Ca2+] profiles of the three cores are seen in the same period as the 7-9% increase in the GISP2 accumulation rate. We conclude that changes of the atmospheric circulation are likely to have occurred in this period, altering the spatial gradients in Greenland and resulting in larger variations between the records. ADDITIONAL REFERENCE: The match points down to 1609.45 m NGRIP depth have been published in: S.O. Rasmussen, K.K. Andersen, A.M. Svensson, J.P. Steffensen, B.M. Vinther, H.B. Clausen, M.-L. Siggaard-Andersen, S.J. Johnsen, L.B. Larsen, D. Dahl-Jensen, M. Bigler, R. Röthlisberger, H. Fischer, K. Goto-Azuma, M.E. Hansson, and U. Ruth. 2006. A new Greenland ice core chronology for the last glacial termination Journ. Geophys. Res., vol. 111, D06102, doi:10.1029/2005JD006079 GEOGRAPHIC REGION: Greenland PERIOD OF RECORD: 11.7-32.44 ka b2k (years relative to A.D. 2000). FUNDING SOURCES: NGRIP is directed and organized by the Ice and Climate Research group, Niels Bohr Institute, University of Copenhagen. It is supported by funding agencies in Denmark (SNF), Belgium (FNRS-CFB), France (IPEV and INSU/CNRS), Germany (AWI), Iceland (RannIs), Japan (MEXT), Sweden (SPRS), Switzerland (SNF) and the USA (NSF, Office of Polar Programs). The construction of the GICC05 time scale, icluding the present work, was funded by the Carlsberg Foundation. DESCRIPTION: Match points used for synchronization of NGRIP, GRIP, and GISP2. The file contains the match points used for the transfer of the GICC05 time scale from NGRIP to GRIP and GISP2. The three cores have been matched using mainly volcanic markers. The uncertainty of the match point depths is discussed in the Quat. Sci. Res. paper referenced above. Synchronized data from the three cores can be obtained from www.icecores.dk or from IGBP PAGES/World Data Center for Paleoclimatology (*) The NGRIP1 core reaches down to a depth of 1372 m. The NGRIP2 core (drilled 20 meters away from the NGRIP1 core) reaches from surface to bedrock, but high-resolution measurements have only been carried out downwards from 1346 m. In the 26 m overlap zone, the cores are offset by 0.43 m on average, probably due to uncertainties in the logging procedure (see Schøtt Hvidberg et al., Ann. Glac. 35, 2002). Thus, the same features appear at larger depths in the NGRIP1 than in the NGRIP2 core. The first 5 match points are given as NGRIP1 depths, while the remaining depths are NGRIP2 depths. DATA: Column 1: NGRIP depth (m) SEE NOTE (*) ABOVE Column 2: GRIP depth (m) Column 3: GISP2 depth (m) 1228.64 1334.01 1392.61 1273.3 1380.35 1439.75 1296.12 1404.3 1463.71 1309.99 1418.7 1477.87 1341.28 1452.85 1511.41 1380.18 1496.02 1554.34 1409.84 1528.59 1586.99 1426.17 1547.1 1605.06 1457.67 1583.9 1639.79 1470.6 1598.9 1653.9 1473.84 1602.6 1657.4 1476.52 1605.75 1660.33 1479.68 1609.4 1663.8 1485.1 1615.65 1669.75 1487.44 1618.35 1672.48 1488.57 1619.74 1673.75 1491.36 1623.05 1676.85 1492.61 1624.5 1678.24 1495.68 1627.7 1681.28 1496.37 1628.44 1681.96 1501.83 1634.6 1687.75 1504.02 1637.1 1690.06 1506.1 1639.55 1692.32 1508.05 1641.7 1694.24 1517.98 1652.89 1704.44 1522.15 1657.5 1708.64 1524.8 1660.45 1711.24 1527.35 1663.35 1713.9 1529.02 1665.26 1715.71 1530.5 1667 1717.27 1531.75 1668.51 1718.68 1538.39 1676.25 1725.78 1545.65 1684.66 1733.62 1556.83 1697.69 1745.64 1563.08 1705.06 1752.47 1564.5 1706.65 1753.94 1567.56 1710.2 1757.26 1570.5 1713.74 1760.39 1577.6 1721.72 1767.97 1580.71 1725.4 1771.5 1587.62 1733.75 1779.16 1590.45 1736.75 1782.22 1595.1 1742.31 1787.43 1601.59 1749.88 1794.47 1604.93 1753.72 1798.16 1606.57 1755.5 1799.8 1607.45 1756.55 1800.73 1609.45 1758.71 1802.88 1610.8 1760.19 1804.23 1612 1761.46 1805.41 1614.72 1764.35 NaN 1619.57 1769.52 1812.91 1621.54 1771.62 NaN 1625.58 1775.82 1818.89 1627.96 1778.34 1821.27 1642.66 1793.37 1835.43 1645.83 1796.72 1838.6 1687.77 1840.78 1883.03 1688.68 NaN 1883.92 1692.63 1845.56 NaN 1693.68 1846.6 NaN NaN 1847.87 1890.11 1699.82 1852.61 1894.73 1705.79 NaN 1900.61 NaN 1863.67 1905.31 1714.18 1867.33 1908.76 1716.15 1869.39 1910.69 1719.13 1872.49 NaN 1721.32 1874.76 1915.73 1728.59 1882.23 1922.77 NaN 1892.18 1932.03 1770.81 1926.34 1963.66 1782.66 1939.26 NaN 1783.7 1940.37 NaN 1798.35 1955.95 1990.98 1802.27 1960.03 NaN 1814.92 NaN 2006.77 1820.39 1978.58 2012.06 1831.58 NaN 2022.79 1840.22 1997.83 2030.74 1843.68 2001.13 2033.89 NaN 2018.28 2049.96 1862.58 2018.92 2050.57 1864.02 2020.43 2051.97 1866.21 2022.53 2054.07 1866.87 2023.14 2054.62 1868.55 2024.82 NaN NaN 2025.98 2057.25 1870.39 2026.64 2057.85 1871.39 2027.53 NaN 1872.25 2028.27 2059.49 1880.01 2035.25 2066.16 1888.7 2043.41 2074.09 1889.86 2044.51 2075.17 1892.66 NaN 2077.4 1894.01 2048.24 NaN 1902.84 2055.99 2086.38 NaN 2057.36 2087.71 1916.8 2068.05 NaN 1918.95 2069.76 2099.52 1929.87 2079.37 2108.9 1931.05 2080.41 2109.92 1939.51 2087.83 2117.07 1939.94 2088.21 2117.4 1944.45 2092.24 2121.23 1946.54 2094.09 2123.05 1947.34 2094.83 2123.75 1947.94 2095.39 2124.27 1948.72 2096.11 2124.95 1949.23 2096.59 2125.4 1949.57 2096.92 2125.72 1950.07 NaN 2126.15 1950.45 2097.75 2126.51 1951.09 2098.33 2127.05