# 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/tierney2017gc27.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 GC27 # Location: Ocean>Atlantic Ocean>North Atlantic Ocean # Country: # Northernmost_Latitude: 30.88 # Southernmost_Latitude: 30.88 # Easternmost_Longitude: -10.63 # Westernmost_Longitude: -10.63 # Elevation: -1258 #--------------------------------------- # Data_Collection # Collection_Name: Tierney2017GC27 # First_Year: 28847 # Last_Year: 867 # Time_Unit: cal yr BP # Core_Length: # Notes: #--------------------------------------- # Chronology_Information # Chronology: # # depth_top depth_bottom MaterialDated 14C.raw 14C.raw_err datemeth calib_curve delta-R delta-R_1sig calib.14C calib.14C_1sig calib_method rejected # 0 1 G. bulloides/mixed planktonic forams 1035 64 14C AMS Marine13 130 25 523 58 OxCal 4.2 no # 4 5 G. bulloides/mixed planktonic forams 1790 61 14C AMS Marine13 130 25 1216 69 OxCal 4.2 no # 30 31 G. bulloides/mixed planktonic forams 5990 35 14C AMS Marine13 130 25 6277 49 OxCal 4.2 no # 60 61 G. bulloides/mixed planktonic forams 10390 130 14C AMS Marine13 130 25 11272 194 OxCal 4.2 no # 77 78 G. bulloides/mixed planktonic forams 12110 60 14C AMS Marine13 130 25 13439 79 OxCal 4.2 no # 92 93 G. bulloides/mixed planktonic forams 14800 94.5 14C AMS Marine13 130 25 17280 148 OxCal 4.2 no # 119 129 G. bulloides/mixed planktonic forams 17240 90 14C AMS Marine13 130 25 20197 134 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 2.5 867 -130.2 -130.2 -30.64 -16.6 -19.5 -13.6 129 72 222 5.5 1345 -135.3 -135.2 -31.13 -22.8 -25.7 -19.9 383 220 628 9.5 2133 -131.7 -131.6 -30.85 -18.6 -21.3 -15.6 184 103 299 11.5 2535 -131.9 -131.9 -30.33 -18.1 -21.2 -15.3 177 105 307 14.5 3141 -132.1 -132.3 -30.07 -18.3 -20.9 -15.7 171 101 284 17.5 3745 -132.3 -132.6 -30.1 -18.5 -21.4 -15.7 181 105 313 19.5 4148 -135.4 -135.6 -30.41 -22.4 -25.3 -19.6 355 216 588 20.5 4351 -134.8 -135.0 -30.17 -21.6 -24.4 -18.7 308 185 517 21.5 4551 -135.1 -135.3 -30.11 -21.7 -24.8 -18.7 303 176 501 22.5 4753 -135.4 -135.6 -30.4 -22.2 -25.3 -19.3 330 203 541 23.5 4954 -135 -135.1 -30.15 -21.6 -24.6 -18.5 308 188 496 24.5 5156 -139.7 -139.9 -30.02 -26.7 -29.6 -23.9 745 456 1235 26.5 5558 -136.4 -136.7 -30.01 -23.1 -26.0 -20.3 396 237 635 28.5 5958 -139.5 -139.9 -29.31 -25.9 -29.1 -23.5 656 388 1114 30.5 6277 -135.9 -136.3 -29.21 -21.9 -24.8 -19.0 316 190 540 32.5 6553 -141.5 -142.0 -29.29 -28.3 -31.3 -25.6 1000 601 1651 34.5 6894 -138 -138.5 -28.8 -24.0 -27.0 -21.3 456 279 758 36.5 7237 -145.1 -145.7 -28.66 -32.1 -34.9 -29.2 1767 1023 2913 39.5 7752 -145 -145.7 -28.92 -32.1 -35.0 -29.4 1870 1100 3065 42.5 8270 -145.1 -145.8 -28.45 -31.9 -34.7 -29.0 1593 932 2711 45.5 8785 -142.4 -143.0 -27.85 -27.8 -30.9 -24.9 933 545 1559 47.5 9129 -144.7 -145.3 -27.97 -30.9 -33.9 -28.1 1462 841 2488 49.5 9472 -146.3 -147.1 -28.27 -33.4 -36.1 -30.2 2132 1226 3411 51.5 9817 -136.8 -137.8 -28.49 -23.0 -25.9 -20.0 390 232 639 53.5 10159 -136.9 -138.1 -27.7 -22.1 -25.3 -19.5 346 210 577 55.5 10498 -133 -134.3 -27.98 -18.3 -21.5 -15.2 178 104 299 58.5 10995 -136.3 -137.7 -27.7 -21.9 -24.7 -18.9 315 190 535 59.5 11146 -130.5 -132.1 -28.1 -15.7 -18.9 -13.2 118 68 193 60.5 11272 -131 -132.8 -28.48 -17.2 -20.1 -14.3 139 79 240 61.5 11398 -127.4 -129.3 -27.92 -12.5 -15.7 -9.5 65 35 113 62.5 11529 -125.4 -127.5 -28.32 -11.2 -14.0 -8.0 53 26 92 63.5 11658 -129 -131.3 -28.17 -15.0 -18.1 -12.2 97 58 161 65.5 11919 -124.4 -127.0 -28.24 -10.1 -13.1 -7.4 47 26 78 67.5 12181 -129.2 -132.0 -28.9 -16.6 -19.5 -13.6 136 79 224 69.5 12444 -129.8 -132.7 -28.45 -17.0 -19.7 -14.0 143 86 235 73.5 12969 -125.7 -128.9 -28.57 -13.0 -15.9 -9.9 71 37 128 76.5 13345 -130.1 -133.6 -28.29 -17.9 -20.8 -15.1 167 93 269 78.5 13623 -128.3 -132.1 -28.4 -16.0 -19.1 -13.3 121 72 199 80.5 14146 -130.5 -134.7 -28.23 -19.2 -22.2 -16.4 204 120 338 81.5 14415 -133 -137.4 -27.98 -21.7 -24.9 -18.9 311 188 512 83.5 14955 -128.5 -133.4 -28.35 -17.6 -20.6 -14.9 166 95 281 85.5 15497 -126.1 -131.5 -28.33 -15.4 -18.6 -12.6 110 66 185 86.5 15769 -127.1 -132.8 -28.42 -17.2 -20.0 -14.0 144 81 234 89.5 16575 -125 -131.2 -28.67 -15.7 -18.4 -12.6 116 68 183 91.5 17086 -125.3 -131.8 -28.74 -16.3 -19.1 -13.4 126 73 210 93.5 17382 -125 -131.6 -28.54 -15.8 -19.0 -13.0 118 70 198 96.5 17695 -122.6 -129.4 -28.96 -13.7 -16.7 -10.8 80 48 132 99.5 18023 -122.1 -129.1 -28.91 -13.4 -16.2 -10.8 79 45 131 101.5 18244 -124.2 -131.1 -28.1 -14.7 -17.7 -12.0 96 59 156 104.5 18575 -120.7 -127.6 -28.31 -11.1 -14.0 -8.2 50 28 88 107.5 18908 -124.5 -131.3 -28.22 -15.0 -18.1 -11.9 97 55 167 111.5 19351 -118.6 -125.4 -28.04 -8.3 -11.2 -5.4 32 17 56 114.5 19681 -121.1 -127.9 -28.39 -11.6 -14.4 -8.7 59 34 95 117.5 20002 -121.9 -128.8 -28.38 -12.5 -15.4 -9.7 69 40 114 120.5 20332 -123.3 -130.1 -28.51 -14.2 -17.0 -11.3 91 52 148 126.5 21305 -121.5 -128.1 -28.29 -11.5 -14.5 -8.6 60 34 100 131.5 22142 -124.1 -130.6 -28.15 -14.3 -17.1 -11.4 90 52 148 136.5 22978 -120.9 -127.3 -28.39 -10.9 -13.8 -7.9 50 27 85 141.5 23817 -121.5 -127.9 -28.32 -11.2 -14.1 -8.5 54 30 93 146.5 24655 -120.4 -126.7 -28.15 -9.8 -13.0 -7.1 45 26 75 151.5 25494 -121.4 -127.6 -28.21 -11.1 -14.1 -8.0 51 27 89 156.5 26331 -121.1 -127.3 -28.27 -10.8 -13.5 -7.9 50 27 82 161.5 27171 -122.6 -128.8 -28.09 -12.3 -15.1 -9.3 63 34 105 166.5 28010 -121.3 -127.2 -28.39 -10.7 -13.7 -7.9 49 28 85 171.5 28847 -124.6 -130.3 -28.52 -14.2 -17.4 -11.4 92 52 154