Lake Edward 1400 Year High Resolution Calcite Mg Data ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!! NAME OF DATA SET: Lake Edward 1400 Year High Resolution Calcite Mg Data LAST UPDATE: 3/2007 (Original receipt by WDC Paleo) CONTRIBUTOR: James Russell, Brown University IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2007-032 SUGGESTED DATA CITATION: Russell, J.M. and T.C. Johnson. 2007. Lake Edward 1400 Year High Resolution Calcite Mg Data. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2007-032. NOAA/NCDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Russell, J.M. and T.C. Johnson. 2007. Little Ice Age drought in equatorial Africa: Intertropical Convergence Zone migrations and El Niño–Southern Oscillation variability. Geology, Vol. 35, No. 1, pp. 21–24, January 2007. doi: 10.1130/G23125A.1 ABSTRACT: High-resolution analyses of the Mg concentration in authigenic calcite in five cores from Lake Edward provide a water balance history of central equatorial Africa spanning the past 1400 yr. A high ratio of Mg to Ca (%Mg) indicates strong droughts in central Africa during the Little Ice Age (A.D. 1400–1750), in contrast to records from Lake Naivasha, Kenya, which suggest a wet Little Ice Age. This spatial pattern in Africa likely arose due to coupled changes in the high latitudes, the position of the Intertropical Convergence Zone, and the El Niño–Southern Oscillation (ENSO) system. Our results further suggest that the patterns and variability of twentieth-century rainfall in central Africa have been unusually conducive to human welfare in the context of the past 1400 yr. GEOGRAPHIC REGION: East Africa PERIOD OF RECORD: 551 - 1974 AD FUNDING SOURCE: US National Science Foundation grant ATM-0314832. DESCRIPTION: Analyses of authigenic calcite %Mg spanning the past 1400 cal yr B.P. from Lake Edward, East African Rift Valley, Uganda/Democratic Republic of the Congo. Lake Edward: 0° 25'S, 29° 45' E, 917m elev, 117m max depth, ~2400km2. High resolution sampling at centimeter scale in four cores from relatively shallow water using X-ray diffraction, and centimeter-scale %Mg analyses in core Edw-4P. Age model derived from fifteen accelerator mass spectrometry (AMS) 14C ages obtained on terrestrial macrofossils from Edw-4P, correlated with AMS 14C and 210Pb-dated features in the %Mg data from other cores visually matched to Edw-4P. DATA: Ratio of Mg to Ca (%Mg) in Lake Edward calcite, Figure 3A, Russell and Johnson (2007). AgeAD %MgRaw 1974.0 16.29 1973.3 16.93 1972.5 16.26 1971.6 15.98 1970.5 16.48 1969.3 16.10 1968.0 16.82 1966.5 16.99 1965.0 16.51 1963.3 16.85 1961.5 16.10 1959.6 17.74 1957.6 17.79 1955.5 16.54 1953.2 17.18 1950.9 14.62 1948.5 15.68 1946.0 15.90 1943.4 16.76 1940.7 15.98 1937.9 16.43 1935.1 16.32 1932.1 16.40 1929.1 16.87 1926.0 16.71 1922.8 16.90 1919.5 16.62 1916.2 16.73 1912.8 16.71 1909.3 16.76 1905.8 16.79 1902.2 17.04 1898.5 16.35 1894.8 16.40 1891.0 16.12 1887.2 16.10 1883.3 15.98 1879.3 16.99 1875.3 17.71 1871.3 17.68 1867.2 18.71 1863.0 18.32 1858.8 18.85 1854.6 18.65 1850.3 17.96 1846.0 17.65 1841.7 17.15 1837.3 16.99 1832.9 17.15 1828.4 17.07 1824.0 16.60 1819.4 17.35 1814.9 16.26 1810.3 17.15 1805.7 16.51 1801.1 15.40 1796.5 16.10 1791.8 16.71 1787.1 17.60 1782.4 17.49 1777.7 17.43 1772.9 18.60 1768.2 18.90 1763.4 20.26 1758.6 20.32 1753.8 20.99 1749.0 20.15 1744.2 20.32 1739.4 19.74 1734.5 20.26 1729.7 21.07 1724.8 22.32 1720.0 22.77 1715.1 22.27 1710.3 21.71 1705.4 21.60 1700.5 21.01 1695.6 21.49 1690.8 21.43 1685.9 21.07 1681.0 20.15 1676.2 20.60 1671.3 20.43 1666.5 20.54 1661.6 20.15 1656.8 20.32 1651.9 20.76 1647.1 20.60 1642.2 19.60 1637.4 20.88 1632.6 20.51 1627.8 20.07 1623.0 19.85 1618.2 20.10 1613.5 20.74 1608.7 19.51 1604.0 20.82 1599.2 19.90 1594.5 20.38 1589.8 20.76 1585.1 19.90 1580.4 20.74 1575.8 21.46 1571.1 20.21 1566.5 19.82 1561.9 19.49 1557.3 19.60 1552.7 20.21 1548.1 20.65 1543.6 21.46 1539.0 21.40 1534.5 21.27 1530.0 21.04 1525.5 21.60 1521.1 20.79 1516.7 20.26 1512.2 20.74 1507.8 20.15 1503.5 19.63 1499.1 19.21 1494.8 19.38 1490.5 19.68 1486.2 17.93 1481.9 19.88 1477.6 19.74 1473.4 19.13 1469.2 19.24 1465.0 18.99 1460.8 18.99 1456.7 18.68 1452.6 19.35 1448.5 18.15 1444.4 18.51 1440.3 18.54 1436.3 18.49 1432.3 18.54 1428.3 17.51 1424.3 17.46 1420.4 17.37 1416.5 17.10 1412.6 16.93 1408.7 16.37 1404.9 17.46 1401.0 17.26 1397.2 17.35 1393.4 17.43 1389.7 17.54 1385.9 17.90 1382.2 16.87 1378.5 16.85 1374.8 16.82 1371.2 16.04 1367.6 17.71 1364.0 17.43 1360.4 17.71 1356.8 18.62 1353.3 18.93 1349.8 18.57 1346.3 17.43 1342.8 17.29 1339.3 16.90 1335.9 16.68 1332.5 16.87 1329.1 16.93 1325.7 16.82 1322.4 17.43 1319.0 17.93 1315.7 18.62 1312.4 19.07 1309.2 18.60 1305.9 19.65 1302.7 18.54 1299.5 19.65 1296.3 19.49 1293.1 19.13 1290.0 19.10 1286.8 20.01 1283.7 19.35 1280.6 18.10 1277.6 18.04 1274.5 17.90 1271.4 18.01 1268.4 17.82 1265.4 17.40 1262.4 17.71 1259.5 17.62 1256.5 16.85 1253.6 17.29 1250.6 16.96 1247.7 17.62 1244.8 17.68 1242.0 18.74 1239.1 17.99 1236.3 18.15 1233.4 19.04 1230.6 18.49 1227.8 19.54 1225.0 19.10 1222.3 19.13 1219.5 19.35 1216.8 20.74 1214.0 20.63 1211.3 19.54 1208.6 19.71 1205.9 21.27 1203.2 21.27 1200.6 19.79 1197.9 19.99 1195.3 20.24 1192.6 20.35 1190.0 20.18 1187.4 21.82 1184.8 22.38 1182.2 21.54 1179.6 21.35 1177.1 21.79 1174.5 20.43 1172.0 20.51 1169.4 20.15 1166.9 20.49 1164.4 20.43 1161.9 20.40 1159.3 20.60 1156.8 20.65 1154.4 20.32 1151.9 20.46 1149.4 20.79 1146.9 20.01 1144.5 19.76 1142.0 20.60 1139.6 19.79 1137.1 19.90 1134.7 20.10 1132.3 19.32 1129.9 18.85 1127.4 19.43 1125.0 20.04 1122.6 19.93 1120.2 19.18 1117.8 19.21 1115.4 18.26 1113.0 18.88 1110.7 19.26 1108.3 18.12 1105.9 20.74 1103.5 20.57 1101.2 20.90 1098.8 19.35 1096.4 19.21 1094.1 19.35 1091.7 18.96 1089.4 20.01 1087.0 20.49 1084.6 19.79 1082.3 20.15 1079.9 20.68 1077.6 20.49 1075.3 18.60 1072.9 18.32 1070.6 18.46 1068.2 18.54 1065.9 18.49 1063.5 18.24 1061.2 19.68 1058.9 20.93 1056.5 19.46 1054.2 20.40 1051.8 21.15 1049.5 19.76 1047.2 20.65 1044.8 20.07 1042.5 19.65 1040.1 19.88 1037.8 20.13 1035.4 19.65 1033.1 18.82 1030.7 18.71 1028.4 18.57 1026.0 17.82 1023.7 17.49 1021.3 16.65 1019.0 16.32 1016.6 16.87 1014.3 17.43 1011.9 17.24 1009.6 16.65 1007.2 17.71 1004.8 19.46 1002.5 18.82 1000.1 16.93 997.7 17.37 995.3 18.26 993.0 17.37 990.6 16.43 988.2 17.37 985.8 17.68 983.4 17.43 981.1 17.76 978.7 17.07 976.3 19.26 973.9 19.49 971.5 18.96 969.1 19.38 966.7 18.65 964.3 18.15 961.9 17.49 959.5 18.26 957.0 17.85 954.6 15.29 952.2 18.65 949.8 18.79 947.4 18.54 944.9 18.82 942.5 17.54 940.1 18.93 937.6 20.43 935.2 19.49 932.8 19.18 930.3 19.35 927.9 19.74 925.5 19.74 923.0 19.74 920.6 20.50 915.7 20.54 909.5 22.02 903.4 22.82 897.2 20.17 884.9 21.97 872.6 19.87 860.2 21.77 847.9 18.63 835.6 21.41 823.4 20.36 811.2 20.95 808.8 21.25 796.8 19.65 784.8 20.04 773.0 19.58 761.4 20.79 750.0 20.72 738.7 20.66 727.7 20.40 716.9 21.12 706.4 21.35 696.2 22.23 686.3 21.35 676.6 21.48 667.3 21.15 658.3 20.27 649.7 20.14 641.4 21.28 633.3 19.74 625.6 19.02 611.1 20.50 604.2 19.51 597.5 20.10 591.0 20.92 584.6 20.23 578.2 20.07 571.9 20.30 565.4 16.61 558.8 17.13 551.9 17.75