# 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/tierney2017gc37.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 GC37 # Location: Ocean>Atlantic Ocean>North Atlantic Ocean # Country: # Northernmost_Latitude: 26.816 # Southernmost_Latitude: 26.816 # Easternmost_Longitude: -15.118 # Westernmost_Longitude: -15.118 # Elevation: -2771 #--------------------------------------- # Data_Collection # Collection_Name: Tierney2017GC37 # First_Year: 24978 # Last_Year: 1250 # 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 1905 61 14C AMS Marine13 130 25 1344 71 OxCal 4.2 no # 14 15 G. bulloides/mixed planktonic forams 4100 1 14C AMS Marine13 130 25 3981 94 OxCal 4.2 no # 18 19 G. bulloides/mixed planktonic forams 4975 58.5 14C AMS Marine13 130 25 5121 98 OxCal 4.2 no # 28 29 G. bulloides/mixed planktonic forams 6335 35 14C AMS Marine13 130 25 6657 58 OxCal 4.2 no # 45 46 G. bulloides/mixed planktonic forams 9740 64 14C AMS Marine13 130 25 10448 96 OxCal 4.2 no # 57 58 G. bulloides/mixed planktonic forams 10495 50 14C AMS Marine13 130 25 11398 128 OxCal 4.2 no # 82 83 G. bulloides/mixed planktonic forams 14460 78 14C AMS Marine13 130 25 N/A N/A OxCal 4.2 yes # 119 120 G. bulloides/mixed planktonic forams 14080 60 14C AMS Marine13 130 25 16372 126 OxCal 4.2 no # 177 178 G. bulloides/mixed planktonic forams 20780 160 14C AMS Marine13 130 25 24275 205 OxCal 4.2 no # 297 298 G. bulloides/mixed planktonic forams 32870 420 14C AMS Marine13 130 25 36641 650 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 3.5 1250 -132 -131.9 -28.04 -15.8 -18.7 -12.9 137 78 239 5.5 1577 -125.6 -125.5 -28.19 -8.6 -11.5 -5.7 38 21 66 7.5 2095 -122.9 -122.7 -27.46 -4.5 -7.3 -1.6 18 9 32 9.5 2667 -133.4 -133.5 -27.32 -16.7 -19.6 -13.7 158 87 277 11.5 3238 -130.5 -130.7 -27.14 -13.4 -16.4 -10.5 89 49 158 12.5 3522 -133 -133.3 -27.08 -16.1 -19.0 -13.2 144 86 244 13.5 3752 -132.5 -132.8 -26.42 -14.9 -17.9 -12.0 107 61 188 14.5 3981 -134.6 -134.9 -26.4 -17.2 -19.9 -14.1 162 92 280 15.5 4267 -131.1 -131.3 -27.2 -14.2 -17.2 -11.0 95 54 168 16.5 4552 -129.8 -130.0 -26.95 -12.4 -15.3 -9.5 75 43 127 17.5 4837 -141 -141.1 -26.85 -24.9 -27.9 -21.9 691 374 1259 18.5 5121 -135.4 -135.5 -27 -18.7 -21.6 -15.8 226 132 409 19.5 5259 -136.9 -137.1 -27.3 -20.7 -23.7 -17.9 323 186 568 20.5 5396 -138.8 -139.0 -26.9 -22.5 -25.3 -19.6 443 243 809 21.5 5560 -143.5 -143.8 -26.81 -27.9 -30.9 -24.9 1248 648 2382 22.5 5723 -140.7 -141.0 -26.48 -24.4 -27.5 -21.3 635 349 1207 23.5 5890 -144.2 -144.6 -26.3 -28.0 -31.2 -25.4 1285 672 2442 25.5 6222 -137.4 -137.8 -26.62 -20.8 -23.8 -17.9 341 194 610 28.5 6657 -135.7 -136.2 -26.23 -18.8 -21.8 -15.9 227 128 392 30.5 7029 -141.6 -142.1 -26.18 -25.3 -28.2 -22.3 755 404 1420 33.5 7729 -143.9 -144.6 -26.19 -28.0 -31.2 -24.8 1170 622 2240 35.5 8197 -142.3 -143.0 -26.42 -26.6 -29.4 -23.6 927 500 1729 38.5 8900 -138.5 -139.1 -25.28 -20.8 -24.2 -17.6 325 183 603 41.5 9603 -133.7 -134.6 -25.43 -15.7 -19.0 -12.8 141 77 259 43.5 10058 -135.3 -136.4 -25.47 -18.1 -21.3 -15.0 205 113 372 48.5 10678 -139.3 -140.6 -25.83 -23.1 -26.4 -20.1 522 291 976 51.5 10929 -139 -140.4 -25.75 -22.9 -26.0 -19.9 492 265 937 54.5 11177 -135.1 -136.7 -25.15 -17.9 -21.2 -14.8 197 116 352 57.5 11398 -133.8 -135.7 -25.22 -17.1 -20.2 -13.7 173 91 309 60.5 11639 -131.1 -133.3 -25.08 -14.3 -17.4 -11.1 99 54 177 62.5 11799 -122.4 -124.9 -24.51 -3.9 -7.3 -0.2 15 7 31 64.5 11959 -122.7 -125.4 -24.83 -4.6 -8.2 -1.3 17 8 34 66.5 12121 -122.4 -125.2 -24.98 -4.6 -8.0 -1.5 17 9 34 69.5 12362 -120.8 -123.7 -24.81 -2.9 -6.2 0.2 13 6 25 71.5 12524 -123.7 -126.7 -24.41 -5.9 -9.2 -2.7 23 12 43 74.5 12767 -119.1 -122.2 -24.72 -1.1 -4.6 2.0 9 4 19 77.5 13010 -127.9 -131.1 -23.69 -10.1 -14.0 -6.8 48 25 92 82.5 13413 -126.1 -129.7 -23.68 -8.6 -12.0 -5.1 35 18 69 88.5 13900 -126.9 -130.9 -23.26 -9.4 -13.3 -5.9 43 21 83 94.5 14386 -124 -128.4 -23.14 -6.5 -10.5 -2.8 26 12 53 100.5 14872 -119.6 -124.4 -23.2 -1.9 -5.8 1.5 11 5 22 104.5 15196 -120.1 -125.2 -23.86 -3.7 -7.4 -0.1 16 8 32 108.5 15518 -121.8 -127.3 -23.3 -5.4 -9.2 -1.9 20 10 41 112.5 15839 -120.9 -126.7 -24.35 -6.0 -9.3 -2.6 22 11 41 116.5 16154 -121.4 -127.4 -25.86 -8.3 -11.4 -5.1 35 18 61 120.5 16491 -114 -120.2 -25.22 0.5 -2.9 4.0 7 3 14 124.5 17018 -115.2 -121.7 -24.83 -0.7 -4.1 2.9 9 4 17 128.5 17567 -115.2 -122.0 -24.75 -1.0 -4.2 2.2 9 4 19 132.5 18121 -116.6 -123.6 -24.94 -3.1 -6.1 0.2 14 7 26 136.5 18672 -119.1 -126.0 -24.15 -4.7 -8.0 -1.3 19 9 35 140.5 19225 -122.6 -129.4 -24.46 -9.1 -12.2 -5.7 39 20 71 144.5 19779 -118.4 -125.3 -24.29 -4.0 -7.3 -0.9 16 8 31 148.5 20330 -117.3 -124.1 -23.91 -2.3 -5.9 1.0 12 6 24 152.5 20883 -118.9 -125.5 -24.1 -4.2 -7.8 -1.0 16 8 32 156.5 21435 -120.3 -126.8 -23.77 -5.3 -8.7 -1.9 19 9 37 160.5 21989 -116.5 -123.0 -23.64 -0.8 -4.3 2.6 9 4 19 164.5 22538 -117.2 -123.6 -23.38 -1.6 -4.9 2.2 10 5 20 168.5 23090 -116.1 -122.5 -23.36 -0.2 -3.6 3.4 8 4 17 172.5 23633 -116.3 -122.6 -23.4 -0.3 -3.9 3.5 8 4 18 176.5 24155 -119.5 -125.7 -23.81 -3.9 -7.7 -0.7 16 8 32 180.5 24568 -117.1 -123.3 -24.12 -1.6 -5.3 1.7 11 5 22 184.5 24978 -114.9 -121.2 -24.25 0.6 -3.2 3.9 7 3 15