# West African Margin 25,000 Year Leaf Wax Isotope Data and Precipitation Reconstruction #----------------------------------------------------------------------- # World Data Service for Paleoclimatology, Boulder # and # NOAA Paleoclimatology Program # National Centers for Environmental Information (NCEI) #----------------------------------------------------------------------- # Template Version 2.0 # NOTE: Please cite original publication, online resource and date accessed when using this data. # If there is no publication information, please cite Investigator, title, online resource and date accessed. # # Description/Documentation lines begin with # # Data lines have no # # # Online_Resource: http://www.ncdc.noaa.gov/paleo/study/21091 # Online_Resource: http://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/tierney2017/tierney2017gc68.txt # # Archive: Paleoceanography # # Parameter_Keywords: biomarkers #--------------------------------------- # Contribution_Date # Date: 2017-01-18 #--------------------------------------- # Title # Study_Name: West African Margin 25,000 Year Leaf Wax Isotope Data and Precipitation Reconstruction #--------------------------------------- # Investigators # Investigators: Tierney, J.; Pausata, F.; deMenocal, P. #--------------------------------------- # Description and Notes # Description: Leaf wax isotope (dD and d13C) and West African precipitation reconstruction from 4 West African Margin marine sediment cores. #--------------------------------------- # Publication # Authors: Jessica E. Tierney, Francesco S.R. Pausata, Peter B. deMenocal # Published_Date_or_Year: 2017-01-18 # Published_Title: Rainfall Regimes of the Green Sahara # Journal_Name: Science Advances # Volume: 3 # Edition: # Issue: 1 # Pages: # Report Number: e1601503 # DOI: 10.1126/sciadv.1601503 # Online_Resource: http://advances.sciencemag.org/content/3/1/e1601503 # Full_Citation: # Abstract: During the "Green Sahara" period (11,000 to 5000 years before the present), the Sahara desert received high amounts of rainfall, supporting diverse vegetation, permanent lakes, and human populations. Our knowledge of rainfall rates and the spatiotemporal extent of wet conditions has suffered from a lack of continuous sedimentary records. We present a quantitative reconstruction of western Saharan precipitation derived from leaf wax isotopes in marine sediments. Our data indicate that the Green Sahara extended to 31N and likely ended abruptly. We find evidence for a prolonged "pause" in Green Sahara conditions 8000 years ago, coincident with a temporary abandonment of occupational sites by Neolithic humans. The rainfall rates inferred from our data are best explained by strong vegetation and dust feedbacks; without these mechanisms, climate models systematically fail to reproduce the Green Sahara. This study suggests that accurate simulations of future climate change in the Sahara and Sahel will require improvements in our ability to simulate vegetation and dust feedbacks. #--------------------------------------- # Funding_Agency # Funding_Agency_Name: National Science Foundation # Grant: OCE-1203892, OCE-0402348 #--------------------------------------- # Funding_Agency # Funding_Agency_Name: David and Lucile Packard Foundation # Grant: #--------------------------------------- # Funding_Agency # Funding_Agency_Name: Swedish Research Council # Grant: Palaeo-constraints on Monsoon Evolution and Dynamics (PACMEDY) #--------------------------------------- # Site Information # Site_Name: OCE437-7 GC68 # Location: Ocean>Atlantic Ocean>North Atlantic Ocean # Country: # Northernmost_Latitude: 19.363 # Southernmost_Latitude: 19.363 # Easternmost_Longitude: -17.282 # Westernmost_Longitude: -17.282 # Elevation: -1396 #--------------------------------------- # Data_Collection # Collection_Name: Tierney2017GC68 # First_Year: 25044 # Last_Year: 1959 # Time_Unit: cal yr BP # Core_Length: # Notes: #--------------------------------------- # Chronology_Information # Chronology: # # depth_top depth_bottom mat.dated 14C.raw 14C.raw_err datemeth calib_curve delta-R delta-R_1sig calib.14C calib.14C_1sig calib_method rejected # 4 5 G. bulloides/mixed planktonic forams 2665 58.5 14C AMS Marine13 130 25 2238 76 OxCal 4.2 no # 18 19 G. bulloides/mixed planktonic forams 4685 61 14C AMS Marine13 130 25 4740 88 OxCal 4.2 no # 26 27 G. bulloides/mixed planktonic forams 5560 35 14C AMS Marine13 130 25 5800 56 OxCal 4.2 no # 40 41 G. bulloides/mixed planktonic forams 7360 70.5 14C AMS Marine13 130 25 7663 71 OxCal 4.2 no # 62 63 G. bulloides/mixed planktonic forams 8600 58.5 14C AMS Marine13 130 25 9131 88 OxCal 4.2 no # 81 82 G. bulloides/mixed planktonic forams 10910 45 14C AMS Marine13 130 25 12079 86 OxCal 4.2 no # 90 91 G. bulloides/mixed planktonic forams 10980 86 14C AMS Marine13 130 25 12427 97 OxCal 4.2 no # 120 121 G. bulloides/mixed planktonic forams 12465 61 14C AMS Marine13 130 25 13853 87 OxCal 4.2 no # 144 145 G. bulloides/mixed planktonic forams 13850 50 14C AMS Marine13 130 25 15962 95 OxCal 4.2 no # 150 151 G. bulloides/mixed planktonic forams 14050 121 14C AMS Marine13 130 25 16283 121 OxCal 4.2 no # 167 168 G. bulloides/mixed planktonic forams 14690 60 14C AMS Marine13 130 25 17291 109 OxCal 4.2 no # 197 198 G. bulloides/mixed planktonic forams 17270 80 14C AMS Marine13 130 25 20121 118 OxCal 4.2 no # 251 252 G. bulloides/mixed planktonic forams 20030 120 14C AMS Marine13 130 25 23439 170 OxCal 4.2 no # 302 303 G. bulloides/mixed planktonic forams 22530 100 14C AMS Marine13 130 25 26255 147 OxCal 4.2 no # #--------------------------------------- # Variables # Data variables follow that are preceded by "##" in columns one and two. # Variables list, one per line, shortname-tab-longname components (9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data) ## depth_cm depth in core,,,cm,,Paleoceanography,,,N ## age_BP age,,,year BP,,Paleoceanography,,,N ## dDwax hydrogen isotopic composition of higher plant leaf waxes (C30 n-acid),,,per mil vs. VSMOW,Annual,Paleoceanography,,compound-specific isotope ratio mass spectrometry,N ## dDwax_iv hydrogen isotopic composition of higher plant leaf waxes (C30 n-acid), corrected for ice volume contributions,,,per mil vs. VSMOW,Annual,Paleoceanography,,IV correction from scaling benthic stack (LR04) to LGM change of 1 per mil in d18O space,N ## d13Cwax carbon isotopic composition of higher plant leaf waxes (C30 n-acid),,,per mil vs. VPDB,Annual,Paleoceanography,,compound-specific isotope ratio mass spectrometry,N ## dDP inferred dD of precipitation, from dDwax and d13Cwax, median values,,,per mil vs. VSMOW,Annual,Paleoceanography,,Bayesian inference,N ## dDP_1s_lower 1-sigma lower bound on dDP,,,per mil vs. VSMOW,Annual,Paleoceanography,,Bayesian inference,N ## dDP_1s_upper 1-sigma upper bound on dDP,,,per mil vs. VSMOW,Annual,Paleoceanography,,Bayesian inference,N ## precip inferred annual precipitation rate from dDP, median values,,,mm/year,Annual,Paleoceanography,,Bayesian inference,N ## precip_1s_lower 1-sigma lower bound on precipitation rate,,,mm/year,Annual,Paleoceanography,,Bayesian inference,N ## precip_1s_upper 1-sigma upper bound on precipitation rate,,,mm/year,Annual,Paleoceanography,,Bayesian inference,N #------------------------ # Data # Data lines follow (have no #) # Data line format - tab-delimited text, variable short name as header # Missing Value: # depth_cm age_BP dDwax dDwax_iv d13Cwax dDP dDP_1s_lower dDP_1s_upper precip precip_1s_lower precip_1s_upper 0.5 1959 -136.9 -136.7 -24.39 -17.2 -20.7 -13.7 126 67 213 3.5 2172 -135.6 -135.5 -24.37 -15.9 -19.2 -12.5 103 51 186 5.5 2357 -136.6 -136.6 -24.17 -16.8 -20.3 -13.3 115 67 196 7.5 2723 -137.7 -137.8 -24.21 -18.2 -21.4 -14.6 151 84 249 9.5 3104 -137.7 -137.9 -24.15 -18.1 -21.6 -14.9 153 84 258 10.5 3291 -136.1 -136.3 -24.46 -16.9 -20.1 -13.5 128 67 209 11.5 3484 -134.8 -135.1 -24.93 -16.0 -19.2 -12.4 100 56 169 12.5 3674 -134.9 -135.2 -25.13 -16.1 -19.6 -12.8 105 59 184 13.5 3862 -138.8 -139.1 -24.36 -19.9 -23.2 -16.4 193 110 313 14.5 4052 -142.7 -143.0 -24.21 -24.2 -27.4 -20.9 404 253 644 15.5 4238 -141.5 -141.7 -24.47 -22.9 -26.3 -19.7 316 185 524 16.5 4428 -139.3 -139.5 -24.38 -20.4 -23.5 -17.1 203 121 335 17.5 4601 -140.4 -140.6 -24.83 -22.0 -25.6 -18.6 303 182 501 18.5 4740 -139.8 -140.0 -24.88 -21.5 -24.7 -18.1 258 147 428 19.5 4847 -140.6 -140.7 -24.67 -22.3 -25.4 -18.6 270 156 455 20.5 4979 -140.3 -140.4 -24.79 -21.8 -25.2 -18.6 278 160 478 21.5 5123 -142.4 -142.5 -24.67 -24.3 -27.6 -20.8 405 245 650 22.5 5268 -143.1 -143.3 -25.15 -25.6 -28.7 -22.1 513 292 839 25.5 5698 -142.1 -142.4 -24.83 -24.1 -27.4 -20.7 390 227 644 28.5 6028 -143.2 -143.6 -25.42 -26.1 -29.6 -22.9 554 342 910 31.5 6449 -146.6 -147.1 -25.55 -30.1 -33.4 -27.0 1109 674 1802 35.5 7015 -145.1 -145.6 -25.54 -28.4 -31.5 -25.2 826 486 1352 40.5 7663 -141.5 -142.2 -25.69 -24.7 -27.9 -21.7 466 265 777 45.5 7987 -137.9 -138.6 -26.91 -22.0 -25.1 -19.0 303 188 498 50.5 8330 -140.7 -141.4 -26.43 -24.6 -27.6 -21.5 449 277 727 55.5 8674 -139.7 -140.3 -26.58 -23.8 -26.7 -20.4 393 240 631 61.5 9071 -142.1 -142.7 -26.4 -26.1 -29.0 -23.1 549 341 886 65.5 9555 -144 -144.9 -26.7 -28.9 -31.9 -25.6 932 577 1561 70.5 10364 -143.4 -144.6 -26.73 -28.7 -31.9 -25.5 915 545 1485 72.5 10687 -142.7 -144.0 -26.47 -27.8 -30.6 -24.6 801 497 1271 74.5 11009 -144.7 -146.1 -25.86 -29.3 -32.6 -26.4 976 595 1591 76.5 11335 -142.8 -144.6 -26 -27.9 -31.0 -24.8 807 505 1275 79.5 11814 -141 -143.4 -24.98 -25.4 -28.9 -22.0 526 306 888 81.5 12079 -140.8 -143.5 -24.63 -25.2 -28.6 -21.6 466 262 806 83.5 12153 -142.2 -144.9 -25.11 -27.4 -30.7 -24.4 729 447 1155 85.5 12230 -135.3 -138.1 -24.46 -19.0 -22.4 -15.4 176 94 303 88.5 12348 -134.4 -137.3 -24.6 -17.8 -21.2 -14.6 140 80 245 91.5 12470 -139 -141.9 -24.76 -23.5 -26.8 -20.3 363 213 599 94.5 12606 -136.7 -139.7 -24.52 -20.7 -24.1 -17.2 216 129 356 97.5 12750 -134.9 -138.0 -25.04 -19.1 -22.7 -16.1 170 102 286 103.5 13040 -137.1 -140.3 -24.75 -21.6 -25.1 -18.3 271 167 432 105.5 13138 -136.2 -139.5 -24.59 -20.7 -24.0 -17.1 215 131 366 109.5 13333 -140.2 -143.7 -25.22 -26.1 -29.3 -22.7 582 338 951 112.5 13477 -138.7 -142.3 -24.71 -23.9 -27.4 -20.5 397 232 633 115.5 13623 -144.7 -148.4 -24.37 -30.4 -33.9 -26.9 1133 630 1960 118.5 13764 -146 -149.8 -24.64 -32.4 -35.5 -29.3 1581 915 2666 121.5 13929 -145.7 -149.6 -24.93 -32.5 -35.6 -29.3 1621 962 2646 123.5 14099 -147.6 -151.7 -24.46 -34.3 -37.6 -30.8 2126 1234 3377 125.5 14276 -144 -148.2 -24.85 -30.7 -34.0 -27.2 1181 707 1932 127.5 14455 -147.1 -151.5 -24.48 -34.1 -37.5 -30.7 2065 1232 3316 129.5 14635 -144.9 -149.4 -25.39 -32.6 -36.0 -29.5 1724 1037 2863 131.5 14818 -141.7 -146.4 -24.94 -28.8 -32.1 -25.4 862 513 1481 133.5 14997 -142.7 -147.5 -24.79 -30.0 -33.5 -26.8 1048 607 1808 138.5 15451 -133.5 -138.8 -24.63 -19.9 -23.2 -16.7 202 121 317 144.5 15962 -133 -138.8 -25.57 -20.8 -24.2 -17.6 231 130 389 149.5 16230 -134.6 -140.6 -25.09 -22.2 -25.6 -19.1 285 165 473 154.5 16518 -134.2 -140.3 -24.84 -21.8 -25.1 -18.5 278 154 469 165.5 17175 -136.7 -143.1 -24.83 -25.2 -28.3 -21.8 458 283 747 170.5 17551 -136.9 -143.5 -25 -25.6 -28.9 -22.5 544 331 861 175.5 18028 -132.6 -139.5 -24.49 -20.5 -23.7 -17.1 217 124 364 180.5 18511 -130.5 -137.3 -24.28 -17.6 -21.3 -14.1 130 73 225 186.5 19094 -130.1 -136.8 -24.18 -17.1 -20.7 -13.6 121 63 211 190.5 19479 -129.4 -136.2 -24.33 -16.5 -19.9 -13.2 114 64 195 195.5 19952 -129.6 -136.4 -24.47 -16.9 -20.2 -13.7 126 70 205 200.5 20298 -128.9 -135.6 -24.25 -15.9 -19.1 -12.3 96 54 162 205.5 20604 -128.8 -135.4 -24.05 -15.4 -18.8 -11.7 94 47 159 212.5 21032 -125.1 -131.6 -23.9 -10.9 -14.4 -7.3 44 23 76 220.5 21529 -126 -132.5 -23.91 -11.6 -15.4 -8.4 50 26 86 228.5 22024 -126.1 -132.5 -23.87 -11.9 -16.0 -8.3 53 27 96 236.5 22518 -127.8 -134.2 -23.59 -13.5 -17.0 -9.6 68 34 120 244.5 23011 -127 -133.3 -23.64 -12.6 -16.2 -9.0 57 30 103 252.5 23491 -127.3 -133.5 -23.67 -12.8 -16.3 -9.2 59 31 104 262.5 24037 -127.7 -133.8 -24.17 -13.6 -17.0 -10.0 69 32 122 270.5 24486 -126.9 -133.1 -24.06 -12.8 -15.8 -9.2 59 30 104 280.5 25044 -128.6 -134.7 -24.09 -14.8 -18.1 -11.3 79 40 141