# Lake Edward, East Africa Calcite Mg Data #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 4.0 # Encoding: UTF-8 # NOTE: Please cite original publication, NOAA Landing Page URL, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, study title, NOAA Landing Page URL, and date accessed. # # Description/Documentation lines begin with # # Data lines have no # # # NOAA_Landing_Page: https://www.ncei.noaa.gov/access/paleo-search/study/5453 # Landing_Page_Description: NOAA Landing Page of this file's parent study, which includes all study metadata. # # Study_Level_JSON_Metadata: https://www.ncei.noaa.gov/pub/data/metadata/published/paleo/json/noaa-lake-5453.json # Study_Level_JSON_Description: JSON metadata of this data file's parent study, which includes all study metadata. # # Data_Type: Paleolimnology # # Dataset_DOI: 10.25921/p4tq-3m10 # # Science_Keywords: #-------------------- # Resource_Links # # Data_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/paleolimnology/eastafrica/edward2003-noaa.txt # Data_Download_Description: NOAA Template File; Calcite Magnesium Data # #-------------------- # Contribution_Date # Date: 2006-10-01 #-------------------- # File_Last_Modified_Date # Date: 2024-06-06 #-------------------- # Title # Study_Name: Lake Edward, East Africa 5400 Year Calcite Mg Data #-------------------- # Investigators # Investigators: Russell, J.M.; Johnson, T.C.; Talbot, M.R. #-------------------- # Description_Notes_and_Keywords # Description: Stacked and detrended Mg in authigenic, inorganic calcite from AMS 14C dated cores 1P, 5M, and 6M 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. Mg percentage in calcite is used to reconstruct lacustrine paleohydrology and climate history. The Mg percentage in calcite rises during evaporative concentration of a lake because of increases in the [Mg2+]/[Ca2+] ratio in lake water. This ratio rises during evaporation because of (1) Ca loss by precipitation and sedimentation of endogenic calcite in the evaporating water body and (2) rising salinity that concentrates dissolved Mg. #-------------------- # Publication # Authors: Russell, J.M., T.C. Johnson, M.R. Talbot # Published_Date_or_Year: 2003 # Published_Title: A 725 yr cycle in the climate of central Africa during the late Holocene # Journal_Name: Geology # Volume: 31 # Edition: # Issue: 8 # Pages: 677-680 # Report_Number: # DOI: 10.1130/G19449.1 # Online_Resource: # Full_Citation: # Abstract: High-resolution analyses of the chemical and stable isotope composition of endogenic calcite from Lake Edward, an equatorial rift lake in central Africa, reveal large oscillations in African climate and moisture balance over the past 5400 yr. These oscillations indicate a series of droughts from 4900 to 400 yr B.P. that define a drought period of ~725 yr. This period may be correlated to variations in the Indian Ocean monsoons, as documented by similar periods in sea-surface salinity records from the northern Indian Ocean. The similarities in periodicity of the Lake Edward and Indian Ocean records may indicate that low-frequency variability within the Indian and Pacific Oceans dominates millennial-scale African moisture balance and the Holocene climate of the tropical Indian Ocean. #-------------------- # Funding_Agency # Funding_Agency_Name: US National Science Foundation # Grant: Graduate Research Fellowship Program, ATM-9805293, EAR-9421566 #-------------------- # Funding_Agency # Funding_Agency_Name: Research Council of Norway # Grant: 103408/730 #-------------------- # Site_Information # Site_Name: Lake Edward # Location: Eastern Africa # Northernmost_Latitude: -0.4167 # Southernmost_Latitude: -0.4167 # Easternmost_Longitude: 29.75 # Westernmost_Longitude: 29.75 # Elevation_m: 917 #-------------------- # Data_Collection # Collection_Name: Lake Edward Russell03 # First_Year: 5400 # Last_Year: 0 # Time_Unit: cal yr BP # Core_Length_m: # Parameter_Keywords: geochemistry # Notes: #-------------------- # Chronology_Information # Chronology: # #-------------------- # Variables # # PaST_Thesaurus_Download_Resource: https://www.ncei.noaa.gov/pub/data/paleo/PaST-thesaurus/SKOS/past-thesaurus-v1.0.rdf # PaST_Thesaurus_Download_Description: Paleoenvironmental Standard Terms (PaST) Thesaurus terms, definitions, and relationships in SKOS format. # # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-var components: what, material, error, units, seasonality, data type, detail, method, C or N for Character or Numeric data) # ## age_calBP age,,,calendar year before present,,paleolimnology,,,N, ## Mg_comp magnesium,calcite,,mole percent,,paleolimnology,composited,x-ray diffraction,N,3 core stack ## Mg_detrend magnesium,calcite,,mole percent,,paleolimnology,composited;detrended,x-ray diffraction,N,3 core stack detrended using second-order polynomial #-------------------- # Data: # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing_Values: age_calBP Mg_comp Mg_detrend 0 16.61 -1.7766 20 17.13 -1.3155 40 17.64 -0.8538 60 18.16 -0.3914 80 18.06 -0.5398 100 17.26 -1.3928 120 16.45 -2.2451 140 16.42 -2.3312 160 16.43 -2.3669 180 17.1 -1.7436 200 18.71 -0.1863 220 20.31 1.3718 240 20.2 1.218 260 19.88 0.8493 280 19.91 0.8334 300 20.56 1.4366 320 21.2 2.0405 340 20.8 1.594 360 20.19 0.9441 380 19.74 0.4563 400 19.65 0.3254 420 19.56 0.1951 440 19.23 -0.1788 460 18.83 -0.6181 480 18.68 -0.8017 500 19.26 -0.2621 520 19.83 0.278 540 19.69 0.0966 560 18.77 -0.857 580 17.85 -1.8099 600 19.16 -0.5314 620 20.57 0.8463 640 19.02 -0.7327 660 19.57 -0.2228 680 20.1 0.2813 700 20.83 0.9839 720 21.86 1.9802 740 22.85 2.94 760 23.27 3.3372 780 23.52 3.5621 800 23.65 3.6561 820 23.49 3.4745 840 23.32 3.2818 860 23.08 3.015 880 22.8 2.7062 900 22.33 2.2146 920 22.36 2.2274 940 18.67 -1.4888 960 18.1 -2.0735 980 19 -1.1928 1000 19.12 -1.0993 1020 19.48 -0.7575 1040 19.97 -0.286 1060 20.03 -0.2383 1080 20.34 0.0518 1100 20.65 0.3419 1120 21.48 1.1607 1140 22.04 1.7087 1160 21.55 1.1957 1180 21.51 1.1463 1200 21.33 0.9577 1220 21.15 0.7672 1240 21.4 1.0012 1260 20.71 0.3052 1280 20.3 -0.1202 1300 21.39 0.9622 1320 21.46 1.0229 1340 21.44 0.9979 1360 20.7 0.2444 1380 20.82 0.36 1400 21.47 1.0005 1420 21.66 1.1912 1440 21.81 1.3358 1460 22.09 1.614 1480 21.87 1.3853 1500 20.47 -0.0161 1520 19.36 -1.1303 1540 18.71 -1.7729 1560 18.06 -2.4238 1580 18.29 -2.1986 1600 18.41 -2.079 1620 18.48 -2.0059 1640 18.66 -1.8173 1660 19.17 -1.3098 1680 19.13 -1.3412 1700 19 -1.4723 1720 18.47 -1.998 1740 19.91 -0.5445 1760 20.6 0.1488 1780 20.66 0.2101 1800 21.37 0.9356 1820 22.19 1.7602 1840 23.03 2.6088 1860 23.59 3.1839 1880 22.96 2.5608 1900 21.39 1.0077 1920 19.93 -0.4411 1940 19.8 -0.5585 1960 19.65 -0.7003 1980 19.47 -0.864 2000 19.29 -1.0319 2020 18.93 -1.3774 2040 17.05 -3.2406 2060 17.13 -3.1383 2080 18.15 -2.1054 2100 17.31 -2.9211 2120 18.8 -1.4194 2140 18.87 -1.3249 2160 17.73 -2.4474 2180 17.85 -2.302 2200 18.35 -1.7791 2220 17.59 -2.5175 2240 16.21 -3.8795 2260 16.59 -3.4744 2280 16.72 -3.3153 2300 16.67 -3.348 2320 16.38 -3.6124 2340 16.23 -3.7333 2360 15.91 -4.0244 2380 15.75 -4.1589 2400 15.95 -3.9248 2420 16.65 -3.2017 2440 17.68 -2.1343 2460 18.51 -1.2764 2480 18.62 -1.1409 2500 18.51 -1.2162 2520 18.81 -0.8861 2540 19.26 -0.3969 2560 19.54 -0.0867 2580 20.08 0.4882 2600 20.61 1.0526 2620 21.32 1.8036 2640 22.55 3.0748 2660 21.7 2.2535 2680 21.16 1.7583 2700 20.99 1.6252 2720 20.22 0.8909 2740 20.78 1.4946 2760 20.21 0.9664 2780 19.22 0.0166 2800 19.08 -0.0779 2820 18.27 -0.8432 2840 18.47 -0.6077 2860 18.76 -0.2656 2880 18.45 -0.5325 2900 17.84 -1.0969 2920 18.47 -0.4254 2940 18.37 -0.476 2960 17.97 -0.8214 2980 17.89 -0.8571 3000 18.27 -0.4308 3020 18.6 -0.0482 3040 18.99 0.3903 3060 18.31 -0.239 3080 17.52 -0.9736 3100 17.5 -0.9441 3120 17.32 -1.068 3140 16.74 -1.5895 3160 16.66 -1.6201 3180 16.74 -1.4773 3200 16.34 -1.8297 3220 15.56 -2.5507 3240 15.61 -2.4441 3260 15.4 -2.5901 3280 15.63 -2.3053 3300 16.22 -1.6507 3320 17.1 -0.7099 3340 17.62 -0.13 3360 17.62 -0.0668 3380 19.1 1.4739 3400 19.46 1.8919 3420 19.22 1.7189 3440 19.2 1.7638 3460 18.92 1.5449 3480 20.94 3.6387 3500 21.35 4.11 3520 21.39 4.2209 3540 20.84 3.7317 3560 20.27 3.2341 3580 19.7 2.7371 3600 19.31 2.4105 3620 19.23 2.4084 3640 19.17 2.4151 3660 19.1 2.4223 3680 18.81 2.205 3700 18.03 1.4949 3720 17.23 0.7681 3740 16.43 0.042 3760 15.91 -0.398 3780 16.11 -0.1214 3800 16.35 0.1902 3820 16.58 0.5025 3840 16.82 0.8217 3860 17.08 1.1595 3880 17.34 1.499 3900 17.6 1.8391 3920 17.86 2.1785 3940 18.09 2.495 3960 18.32 2.804 3980 18.55 3.1137 4000 18.77 3.4171 4020 18.84 3.577 4040 18.86 3.6806 4060 18.88 3.7847 4080 18.82 3.8169 4100 18.51 3.5907 4120 18.17 3.3423 4140 17.84 3.0964 4160 17.55 2.897 4180 17.28 2.7177 4200 17.01 2.5391 4220 16.53 2.1476 4240 15.66 1.3728 4260 14.79 0.5909 4280 14 -0.1037 4300 13.88 -0.1305 4320 13.9 -0.0165 4340 13.92 0.0984 4360 14.03 0.3124 4380 14.24 0.6114 4400 14.44 0.9111 4420 14.44 1.0087 4440 13.71 0.3834 4460 12.92 -0.3054 4480 12.16 -0.9699 4500 11.95 -1.0761 4520 11.98 -0.9454 4540 12.01 -0.8141 4560 12.11 -0.6094 4580 12.34 -0.2731 4600 12.58 0.0664 4620 12.73 0.3223 4640 12.69 0.393 4660 12.65 0.4576 4680 12.77 0.682 4700 13.37 1.3912 4720 14 2.1343 4740 14.58 2.8192 4760 14.14 2.4892 4780 13.33 1.7923 4800 12.52 1.0961 4820 12.01 0.695 4840 11.95 0.7453 4860 11.89 0.8013 4880 11.82 0.8464 4900 10.68 -0.1816 4920 10.61 -0.1392 4940 10.53 -0.0965 4960 10.4 -0.1143 4980 10.12 -0.2781 5000 9.51 -0.7669 5020 8.8 -1.3609 5040 7.83 -2.2033 5060 6.87 -3.0458 5080 6.25 -3.5462 5100 6.08 -3.5898 5120 6.04 -3.5128 5140 5.99 -3.4351 5160 5.93 -3.3704 5180 5.82 -3.3577 5200 5.78 -3.2769 5220 5.73 -3.1955 5240 5.74 -3.059 5260 6.15 -2.5227 5280 6.64 -1.9053 5300 7.13 -1.2872 5320 7.62 -0.6692 5340 7.71 -0.452 5360 7.45 -0.5733 5380 7.2 -0.6939 5400 6.95 -0.8138