A leaf wax biomarker record of early Pleistocene hydroclimate from West Turkana, Kenya

QUATERNARY SCIENCE REVIEWS

卷:186

Article

Lupien, R. L.¹  Russell, J. M.¹  Feibel, C.²  Beck, C.^2,3  Castaneda, I.⁴  Deino, A.⁵  Cohen, A. S.⁶ 

[1] Brown Univ, Dept Earth Environm & Planetary Sci, 324 Brook St, Providence, RI 02906 USA

[2] Rutgers State Univ, Dept Earth & Planetary Sci, 610 Taylor Rd, Piscataway, NJ 08854 USA

[3] Hamilton Coll, Dept Geosci, 198 Coll Hill Rd, Clinton, NY 13323 USA

[4] Univ Massachusetts, Dept Geosci, 627 North Pleasant St, Amherst, MA 01002 USA

[5] Berkeley Geochronol Ctr, 2455 Ridge Rd, Berkeley, CA 94709 USA

[6] Univ Arizona, Dept Geosci, 1040 East 4th St, Tucson, AZ 85721 USA

关键词: Human evolution;    Paleoclimatology;    Pleistocene;    Continental biomarkers;    Organic geochemistry;    Hydrogen isotopes;    East Africa;    Turkana basin;   

DOI  :  10.1016/j.quascirev.2018.03.012

来源: Elsevier

【 摘 要 】

Climate is thought to play a critical role in human evolution; however, this hypothesis is difficult to test due to a lack of long, high-quality paleoclimate records from key hominin fossil locales. To address this issue, we analyzed organic geochemical indicators of climate in a drill core from West Turkana, Kenya that spans similar to 1.9-1.4 Ma, an interval that includes several important hominin evolutionary transitions. We analyzed the hydrogen isotopic composition of terrestrial plant waxes (delta D-wax)to reconstruct orbital-timescale changes in regional hydrology and their relationship with global climate forcings and the hominin fossil record. Our data indicate little change in the long-term mean hydroclimate during this interval, in contrast to inferred changes in the level of Lake Turkana, suggesting that lake level may be responding dominantly to deltaic progradation or tectonically-driven changes in basin configuration as opposed to hydroclimate. Time-series spectral analyses of the isotopic data reveal strong precession band (21 kyr) periodicity, indicating that regional hydroclimate was strongly affected by changes in insolation. We observe an interval of particularly high-amplitude hydrologic variation at similar to 1.7 Ma, which occurs during a time of high orbital eccentricity hence large changes in processionally-driven insolation amplitude. This interval overlaps with multiple hominin species turnovers, the appearance of new stone tool technology, and hominin dispersal out of Africa, supporting the notion that climate variability played an important role in hominin evolution. (C) 2018 Elsevier Ltd. All rights reserved.

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