# 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/tierney2017gc49.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 GC49 # Location: Ocean>Atlantic Ocean>North Atlantic Ocean # Country: # Northernmost_Latitude: 23.206 # Southernmost_Latitude: 23.206 # Easternmost_Longitude: -17.854 # Westernmost_Longitude: -17.854 # Elevation: -2303 #--------------------------------------- # Data_Collection # Collection_Name: Tierney2017GC49 # First_Year: 25119 # Last_Year: 1043 # 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 1415 64 14C AMS Marine13 130 25 848 71 OxCal 4.2 no # 20 21 G. bulloides/mixed planktonic forams 4530 70.5 14C AMS Marine13 130 25 4557 109 OxCal 4.2 no # 30 31 G. bulloides/mixed planktonic forams 6275 64 14C AMS Marine13 130 25 6572 83 OxCal 4.2 no # 40 41 G. bulloides/mixed planktonic forams 8045 64 14C AMS Marine13 130 25 8374 73 OxCal 4.2 no # 54 55 G. bulloides/mixed planktonic forams 9985 61 14C AMS Marine13 130 25 10754 97 OxCal 4.2 no # 77 78 G. bulloides/mixed planktonic forams 12120 330 14C AMS Marine13 130 25 12807 125 OxCal 4.2 no # 86 87 G. bulloides/mixed planktonic forams 11835 64 14C AMS Marine13 130 25 13224 69 OxCal 4.2 no # 108 109 G. bulloides/mixed planktonic forams 13125 50 14C AMS Marine13 130 25 14965 128 OxCal 4.2 no # 140 141 G. bulloides/mixed planktonic forams 15180 121 14C AMS Marine13 130 25 17835 198 OxCal 4.2 no # 201 203 G. bulloides/mixed planktonic forams 20460 110 14C AMS Marine13 130 25 23965 152 OxCal 4.2 no # 281 282 G. bulloides/mixed planktonic forams 27810 500 14C AMS Marine13 130 25 31385 485 OxCal 4.2 no # 330 331 G. bulloides/mixed planktonic forams 31500 1401 14C AMS Marine13 130 25 36459 996 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 5.5 1043 -128.5 -128.5 -25.52 -8.9 -12.3 -6.0 34 17 66 7.5 1480 -128.1 -128.0 -25.81 -8.9 -12.1 -5.7 33 15 63 9.5 1968 -131.2 -131.0 -25.71 -12.0 -15.3 -9.0 59 30 110 12.5 2702 -132.5 -132.6 -25.74 -14.0 -17.1 -10.6 82 38 157 14.5 3194 -136 -136.2 -25.48 -17.8 -21.0 -14.5 179 95 321 16.5 3683 -138.1 -138.4 -25.97 -20.8 -23.8 -17.5 287 156 550 18.5 4165 -142.4 -142.6 -25.44 -25.1 -28.4 -21.8 658 336 1300 19.5 4361 -138.1 -138.3 -25.89 -20.6 -23.5 -17.4 273 145 522 20.5 4557 -138.3 -138.5 -25.93 -20.8 -23.8 -17.8 299 171 542 21.5 4739 -141 -141.2 -25.79 -23.7 -26.6 -20.6 531 286 973 22.5 4921 -140.3 -140.4 -25.47 -22.3 -25.4 -19.3 409 219 792 24.5 5350 -138.6 -138.8 -25.58 -20.6 -24.0 -17.5 302 161 556 27.5 6003 -141 -141.4 -25.46 -23.5 -26.6 -20.5 520 285 954 30.5 6572 -145.7 -146.2 -25.69 -29.2 -32.3 -26.3 1430 736 2713 33.5 7084 -144 -144.6 -24.68 -26.4 -29.8 -23.0 848 437 1633 35.5 7473 -144.9 -145.5 -25.59 -28.6 -31.6 -25.4 1314 672 2542 38.5 8059 -138.9 -139.6 -24.91 -20.9 -24.0 -17.6 294 156 554 40.5 8374 -138.1 -138.8 -25.34 -20.5 -23.8 -17.2 288 159 535 44.5 9025 -141.9 -142.5 -25.07 -24.6 -27.7 -21.3 570 302 1099 47.5 9569 -140.1 -141.0 -25.08 -22.6 -25.9 -19.4 411 220 760 50.5 10110 -141 -142.1 -24.62 -23.7 -26.8 -20.3 515 266 1016 54.5 10754 -135.3 -136.7 -24.07 -16.8 -20.1 -13.3 142 72 263 58.5 11100 -134.5 -136.1 -24.34 -16.5 -19.7 -12.9 134 72 243 60.5 11281 -135.6 -137.4 -24.16 -17.6 -21.0 -14.1 166 90 304 62.5 11464 -135 -137.0 -24.07 -17.2 -20.3 -13.5 146 76 268 64.5 11647 -134 -136.2 -24.06 -16.1 -19.7 -13.0 125 68 243 66.5 11831 -130.5 -133.0 -24.27 -12.8 -16.2 -9.4 64 31 130 68.5 12013 -130.1 -132.8 -24.19 -12.2 -15.6 -9.1 60 31 117 71.5 12288 -126.5 -129.3 -24.28 -8.6 -11.9 -5.3 33 15 68 74.5 12557 -132.8 -135.8 -23.84 -15.4 -18.8 -12.1 106 54 200 77.5 12807 -135.9 -139.0 -24.2 -19.5 -22.9 -16.2 240 129 456 81.5 12998 -134.8 -138.0 -23.87 -17.9 -21.4 -14.6 183 97 341 84.5 13137 -132.2 -135.5 -23.81 -15.2 -18.8 -11.7 104 54 196 87.5 13293 -132.9 -136.4 -23.72 -15.8 -19.5 -12.6 126 67 238 90.5 13518 -136.3 -139.9 -23.73 -20.1 -23.3 -16.6 248 132 463 93.5 13760 -135.5 -139.3 -23.83 -19.4 -22.9 -16.1 230 127 423 96.5 14003 -135.7 -139.7 -23.49 -19.8 -23.1 -15.9 246 132 451 99.5 14246 -131.4 -135.7 -23.38 -15.0 -18.2 -11.4 89 46 176 102.5 14489 -132.6 -137.1 -23.69 -17.1 -20.3 -13.2 136 66 255 105.5 14728 -134.6 -139.2 -23.59 -19.2 -22.7 -15.7 225 117 436 108.5 14965 -128.7 -133.6 -23.8 -13.0 -16.5 -9.5 65 32 131 111.5 15209 -130.5 -135.6 -24.02 -15.3 -19.0 -12.4 115 57 225 119.5 15932 -126.1 -131.9 -24.59 -11.9 -15.1 -8.7 61 30 112 125.5 16484 -122.3 -128.5 -25.06 -8.5 -11.9 -5.2 30 15 57 131.5 17035 -127.2 -133.6 -24.95 -14.4 -17.6 -11.0 93 47 174 135.5 17400 -126.3 -132.9 -25.09 -13.7 -16.7 -10.5 83 43 152 139.5 17750 -125.6 -132.4 -24.84 -12.8 -16.1 -9.4 66 34 128 143.5 18113 -124.3 -131.2 -24.76 -11.4 -14.6 -8.1 52 25 97 146.5 18408 -126.7 -133.6 -24.48 -13.5 -17.0 -10.1 74 37 148 149.5 18708 -130.9 -137.7 -24.37 -18.1 -21.4 -14.9 194 103 369 153.5 19111 -129.1 -135.8 -23.99 -15.6 -19.0 -11.9 106 57 200 159.5 19713 -127 -133.8 -24.1 -13.6 -16.8 -10.2 80 37 144 164.5 20216 -130.4 -137.1 -23.9 -16.9 -20.4 -13.8 144 75 266 169.5 20722 -125.1 -131.7 -24.05 -11.3 -14.4 -7.7 49 24 97 174.5 21228 -122.5 -129.0 -23.57 -7.4 -11.1 -4.1 25 11 51 179.5 21730 -125.3 -131.7 -23.1 -10.0 -13.4 -6.3 40 18 82 184.5 22235 -122 -128.4 -23.18 -6.2 -10.0 -2.6 20 9 41 189.5 22738 -121.7 -128.1 -23.2 -6.1 -9.5 -2.6 19 9 42 194.5 23242 -123 -129.3 -23.25 -7.5 -10.9 -3.7 25 11 52 199.5 23733 -121.3 -127.5 -23.64 -5.8 -9.8 -2.5 18 8 38 204.5 24181 -123.1 -129.3 -23.47 -7.4 -11.1 -4.0 24 11 51 209.5 24646 -124.5 -130.7 -22.99 -8.6 -12.4 -5.1 33 15 65 214.5 25119 -122.2 -128.34 -22.87 -5.9 -9.5 -2.6 18 8 39