Cooling and drying in northeast Africa across the Pliocene

noaa-ocean-20145 Gulf of Aden DSDP Site 231 Pliocene to late Pleistocene Biomarker Data Liddy, H.M.; Feakins, S.J.; Tierney, J.E. Gulf of Aden DSDP Site 231 Pliocene to late Pleistocene Biomarker Data 2016-08-23 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/20145 Investigator H.M. Liddy Investigator S.J. Feakins Investigator J.E. Tierney earth science paleoclimate paleoceanography notes,null,null,null,null,paleoceanography,null,null,C,* indicates n-C30 data from Feakins et al. 2005 and Feakins et al. 2013 earth science paleoclimate paleoceanography delta 13C,C30 n-alkanoic acid,null,per mil VPDB,null,paleoceanography,null,null,N,leaf wax interpretation earth science paleoclimate paleoceanography delta 13C,C28 n-alkanoic acid,one standard deviation,per mil,null,paleoceanography,null,null,N,standard deviation of replicates; leaf wax interpretation earth science paleoclimate paleoceanography depth,null,null,meter,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography delta 13C,C30 n-alkanoic acid,one standard deviation,per mil,null,paleoceanography,null,null,N,standard deviation of replicates; leaf wax interpretation earth science paleoclimate paleoceanography delta 2H,C28 n-alkanoic acid,null,per mil VSMOW,null,paleoceanography,null,null,N,leaf wax interpretation earth science paleoclimate climate reconstructions|paleoceanography sea water temperature,glycerol dialkyl glycerol tetraether index,one standard deviation upper bound,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,using BAYSPAR subsurface calibration (Tierney and Tingley 2015); based on TEX86 earth science paleoclimate paleoceanography tetraether index of 86 carbon atoms,null,null,dimensionless,null,paleoceanography,null,null,N,null earth science paleoclimate climate reconstructions|paleoceanography sea water temperature,glycerol dialkyl glycerol tetraether index,one standard deviation lower bound,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,using BAYSPAR subsurface calibration (Tierney and Tingley 2015); based on TEX86 earth science paleoclimate paleoceanography delta 13C,C28 n-alkanoic acid,null,per mil VPDB,null,paleoceanography,null,null,N,leaf wax interpretation earth science paleoclimate paleoceanography delta 13C,C32 n-alkanoic acid,one standard deviation,per mil,null,paleoceanography,null,null,N,standard deviation of replicates; leaf wax interpretation earth science paleoclimate paleoceanography branched and isoprenoid tetraether index,null,null,dimensionless,null,paleoceanography,null,null,N,ratio of branched glycerol dialkyl gycerol tetraethers to aquatic isoprenoidal GDGT crenarchaeol earth science paleoclimate climate reconstructions|paleoceanography sea water temperature,glycerol dialkyl glycerol tetraether index,null,degree Celsius,null,climate reconstructions|paleoceanography,null,null,N,Mean calibrated subsurface ocean temperature from TEX86 using BAYSPAR subsurface calibration (Tierney and Tingley 2015) earth science paleoclimate paleoceanography age,null,null,million years ago,null,paleoceanography,null,null,N,null earth science paleoclimate paleoceanography delta 2H,C28 n-alkanoic acid,one standard deviation,per mil,null,paleoceanography,null,null,N,standard deviation of replicates; leaf wax interpretation earth science paleoclimate paleoceanography delta 13C,C32 n-alkanoic acid,null,per mil VPDB,null,paleoceanography,null,null,N,leaf wax interpretation earth science paleoclimate paleocean biomarkers earth science paleoclimate paleocean carbon isotopes geoscientificInformation 5249000 cal yr BP 2001000 cal yr BP Complete 11.89 11.89 48.25 48.25 -2152 -2152 Ocean Indian Ocean Arabian Sea DSDP 231>LATITUDE 11.89>LONGITUDE 48.25 None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. If there is no publication information, please cite investigator, title, online resource, and date accessed. The appearance of external links associated with a dataset does not constitute endorsement by the Department of Commerce/National Oceanic and Atmospheric Administration of external Web sites or the information, products or services contained therein. For other than authorized activities, the Department of Commerce/NOAA does not exercise any editorial control over the information you may find at these locations. These links are provided consistent with the stated purpose of this Department of Commerce/NOAA Web site. English DOC/NOAA/NESDIS/NCEI National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce https://www.ncdc.noaa.gov/data-access/paleoclimatology-data DATA Center Contact Bruce Bauer bruce.a.bauer@noaa.gov paleo@noaa.gov 303-497-6280 303-497-6513

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Boulder CO 80305-3328 USA online ASCII Hannah M. Liddy, Sarah J. Feakins, Jessica E. Tierney 2016 Cooling and drying in northeast Africa across the Pliocene Earth and Planetary Science Letters 449 430-438 10.1016/j.epsl.2016.05.005 http://www.sciencedirect.com/science/article/pii/S0012821X1630214X

Terrestrial records suggest that Northeast Africa experienced drying during the Pliocene; however, these records are often incomplete in time and space, and questions about this shift in climate remain. Here, we use marine sediments from Deep Sea Drilling Project (DSDP) Site 231 in the Gulf of Aden to generate a multi-proxy organic geochemical record of northeast African climate spanning 5.3-2 Ma. This new record provides a regional perspective on climate and serves as context for the fossil record of early hominin evolution. We measured leaf wax carbon (d13Cwax) and hydrogen (dDwax) isotopic composition and TEX86 (tetraether index of 86 carbons) to investigate past changes in vegetation, aridity, and ocean temperature, respectively. In the earliest Pliocene, we infer warm subsurface ocean temperatures from TEX86, semi-arid conditions on land and extensive C4 grasslands based on dDwax, d13Cwax and previously published pollen. After 5 Ma, ocean temperatures gradually cooled, and at 4.3 Ma there was a transition to arid conditions on land based on dDwax and pollen. Grasslands yielded to a mid Pliocene landscape of dry shrublands. This drying appears to be an atmospheric response to cooling ocean temperatures, which may reflect changes in tropical ocean circulation, the intensification of Indian Monsoon winds or perhaps other changes associated with Pliocene cooling. STUDY NOTES: Plio-Pleistocene records of leaf wax carbon and hydrogen isotopes from a marine sediment core from the Gulf of Aden are used to assess changes in vegetation and aridity across the Horn of Africa. During the same interval, Gulf of Aden TEX86 values reflects subsurface ocean temperatures, and BIT index values are used to assess the GDGT contribution from soils.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/liddy2016/liddy2016tex86.txt Data File; GDGT results (TEX86, BIT, SST) from DSDP Site 231 GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/liddy2016/liddy2016d2h.txt Data File; Plant wax hydrogen Isotope data from DSDP Site 231 GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/liddy2016/liddy2016d13c.txt Data File; Plant wax carbon isotope data from DSDP Site 231 USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11